[PATCHv3 0/13] credential helpers

[PATCHv3 0/13] credential helpers

[Jeff King]

Here's the latest re-roll of the credential helpers series. I think this
one is probably ready to go to 'next'.

It's rebased on the latest tip of 'master' (applying it to an older
commit will get you a minor textual conflict in strbuf.c). It
incorporates the erase-safety we discussed, fixes a few commit message
typos, and tweaks the test scripts to make testing the external OS X
helper a little easier.

  [01/13]: test-lib: add test_config_global variant
  [02/13]: t5550: fix typo
  [03/13]: introduce credentials API
  [04/13]: credential: add function for parsing url components
  [05/13]: http: use credential API to get passwords
  [06/13]: credential: apply helper config
  [07/13]: credential: add credential.*.username
  [08/13]: credential: make relevance of http path configurable
  [09/13]: docs: end-user documentation for the credential subsystem
  [10/13]: credentials: add "cache" helper
  [11/13]: strbuf: add strbuf_add*_urlencode
  [12/13]: credentials: add "store" helper
  [13/13]: t: add test harness for external credential helpers

-Peff

[PATCHv3 01/13] test-lib: add test_config_global variant

[Jeff King]

The point of test_config is to simultaneously set a config
variable and register its cleanup handler, like:

  test_config core.foo bar

However, it stupidly assumes that $1 contained the name of
the variable, which means it won't work for:

  test_config --global core.foo bar

We could try to parse the command-line ourselves and figure
out which parts need to be fed to test_unconfig. But since
this is likely the most common variant, it's much simpler
and less error-prone to simply add a new function.

Signed-off-by: Jeff King <peff@peff.net>
---
 t/test-lib.sh |    5 +++++
 1 files changed, 5 insertions(+), 0 deletions(-)

diff --git a/t/test-lib.sh b/t/test-lib.sh
index bdd9513..160479b 100644
--- a/t/test-lib.sh
+++ b/t/test-lib.sh
@@ -379,6 +379,11 @@ test_config () {
 	git config "$@"
 }
 
+test_config_global () {
+	test_when_finished "test_unconfig --global '$1'" &&
+	git config --global "$@"
+}
+
 # Use test_set_prereq to tell that a particular prerequisite is available.
 # The prerequisite can later be checked for in two ways:
 #
-- 
1.7.8.rc2.40.gaf387

[PATCHv3 02/13] t5550: fix typo

[Jeff King]

This didn't have an impact, because it was just setting up
an "expect" file that happened to be identical to the one in
the test before it.

Signed-off-by: Jeff King <peff@peff.net>
---
 t/t5550-http-fetch.sh |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/t/t5550-http-fetch.sh b/t/t5550-http-fetch.sh
index 311a33c..3d6e871 100755
--- a/t/t5550-http-fetch.sh
+++ b/t/t5550-http-fetch.sh
@@ -66,7 +66,7 @@ test_expect_success 'cloning password-protected repository can fail' '
 
 test_expect_success 'http auth can use user/pass in URL' '
 	>askpass-query &&
-	echo wrong >askpass-reponse &&
+	echo wrong >askpass-response &&
 	git clone "$HTTPD_URL_USER_PASS/auth/repo.git" clone-auth-none &&
 	test_cmp askpass-expect-none askpass-query
 '
-- 
1.7.8.rc2.40.gaf387

[PATCHv3 03/13] introduce credentials API

[Jeff King]

There are a few places in git that need to get a username
and password credential from the user; the most notable one
is HTTP authentication for smart-http pushing.

Right now the only choices for providing credentials are to
put them plaintext into your ~/.netrc, or to have git prompt
you (either on the terminal or via an askpass program). The
former is not very secure, and the latter is not very
convenient.

Unfortunately, there is no "always best" solution for
password management. The details will depend on the tradeoff
you want between security and convenience, as well as how
git can integrate with other security systems (e.g., many
operating systems provide a keychain or password wallet for
single sign-on).

This patch provides an abstract notion of credentials as a
data item, and provides three basic operations:

  - fill (i.e., acquire from external storage or from the
    user)

  - approve (mark a credential as "working" for further
    storage)

  - reject (mark a credential as "not working", so it can
    be removed from storage)

These operations can be backed by external helper processes
that interact with system- or user-specific secure storage.

Signed-off-by: Jeff King <peff@peff.net>
---
 .gitignore                                  |    1 +
 Documentation/technical/api-credentials.txt |  241 +++++++++++++++++++++++++++
 Makefile                                    |    3 +
 credential.c                                |  234 ++++++++++++++++++++++++++
 credential.h                                |   28 +++
 t/lib-credential.sh                         |   33 ++++
 t/t0300-credentials.sh                      |  195 ++++++++++++++++++++++
 test-credential.c                           |   38 +++++
 8 files changed, 773 insertions(+), 0 deletions(-)
 create mode 100644 Documentation/technical/api-credentials.txt
 create mode 100644 credential.c
 create mode 100644 credential.h
 create mode 100755 t/lib-credential.sh
 create mode 100755 t/t0300-credentials.sh
 create mode 100644 test-credential.c

diff --git a/.gitignore b/.gitignore
index 8572c8c..7d2fefc 100644
--- a/.gitignore
+++ b/.gitignore
@@ -167,6 +167,7 @@
 /gitweb/static/gitweb.js
 /gitweb/static/gitweb.min.*
 /test-chmtime
+/test-credential
 /test-ctype
 /test-date
 /test-delta
diff --git a/Documentation/technical/api-credentials.txt b/Documentation/technical/api-credentials.txt
new file mode 100644
index 0000000..f624aef
--- /dev/null
+++ b/Documentation/technical/api-credentials.txt
@@ -0,0 +1,241 @@
+credentials API
+===============
+
+The credentials API provides an abstracted way of gathering username and
+password credentials from the user (even though credentials in the wider
+world can take many forms, in this document the word "credential" always
+refers to a username and password pair).
+
+Data Structures
+---------------
+
+`struct credential`::
+
+	This struct represents a single username/password combination
+	along with any associated context. All string fields should be
+	heap-allocated (or NULL if they are not known or not applicable).
+	The meaning of the individual context fields is the same as
+	their counterparts in the helper protocol; see the section below
+	for a description of each field.
++
+The `helpers` member of the struct is a `string_list` of helpers.  Each
+string specifies an external helper which will be run, in order, to
+either acquire or store credentials. See the section on credential
+helpers below.
++
+This struct should always be initialized with `CREDENTIAL_INIT` or
+`credential_init`.
+
+
+Functions
+---------
+
+`credential_init`::
+
+	Initialize a credential structure, setting all fields to empty.
+
+`credential_clear`::
+
+	Free any resources associated with the credential structure,
+	returning it to a pristine initialized state.
+
+`credential_fill`::
+
+	Instruct the credential subsystem to fill the username and
+	password fields of the passed credential struct by first
+	consulting helpers, then asking the user. After this function
+	returns, the username and password fields of the credential are
+	guaranteed to be non-NULL. If an error occurs, the function will
+	die().
+
+`credential_reject`::
+
+	Inform the credential subsystem that the provided credentials
+	have been rejected. This will cause the credential subsystem to
+	notify any helpers of the rejection (which allows them, for
+	example, to purge the invalid credentials from storage).  It
+	will also free() the username and password fields of the
+	credential and set them to NULL (readying the credential for
+	another call to `credential_fill`). Any errors from helpers are
+	ignored.
+
+`credential_approve`::
+
+	Inform the credential subsystem that the provided credentials
+	were successfully used for authentication.  This will cause the
+	credential subsystem to notify any helpers of the approval, so
+	that they may store the result to be used again.  Any errors
+	from helpers are ignored.
+
+Example
+-------
+
+The example below shows how the functions of the credential API could be
+used to login to a fictitious "foo" service on a remote host:
+
+-----------------------------------------------------------------------
+int foo_login(struct foo_connection *f)
+{
+	int status;
+	/*
+	 * Create a credential with some context; we don't yet know the
+	 * username or password.
+	 */
+
+	struct credential c = CREDENTIAL_INIT;
+	c.protocol = xstrdup("foo");
+	c.host = xstrdup(f->hostname);
+
+	/*
+	 * Fill in the username and password fields by contacting
+	 * helpers and/or asking the user. The function will die if it
+	 * fails.
+	 */
+	credential_fill(&c);
+
+	/*
+	 * Otherwise, we have a username and password. Try to use it.
+	 */
+	status = send_foo_login(f, c.username, c.password);
+	switch (status) {
+	case FOO_OK:
+		/* It worked. Store the credential for later use. */
+		credential_accept(&c);
+		break;
+	case FOO_BAD_LOGIN:
+		/* Erase the credential from storage so we don't try it
+		 * again. */
+		credential_reject(&c);
+		break;
+	default:
+		/*
+		 * Some other error occured. We don't know if the
+		 * credential is good or bad, so report nothing to the
+		 * credential subsystem.
+		 */
+	}
+
+	/* Free any associated resources. */
+	credential_clear(&c);
+
+	return status;
+}
+-----------------------------------------------------------------------
+
+
+Credential Helpers
+------------------
+
+Credential helpers are programs executed by git to fetch or save
+credentials from and to long-term storage (where "long-term" is simply
+longer than a single git process; e.g., credentials may be stored
+in-memory for a few minutes, or indefinitely on disk).
+
+Each helper is specified by a single string. The string is transformed
+by git into a command to be executed using these rules:
+
+  1. If the helper string begins with "!", it is considered a shell
+     snippet, and everything after the "!" becomes the command.
+
+  2. Otherwise, if the helper string begins with an absolute path, the
+     verbatim helper string becomes the command.
+
+  3. Otherwise, the string "git credential-" is prepended to the helper
+     string, and the result becomes the command.
+
+The resulting command then has an "operation" argument appended to it
+(see below for details), and the result is executed by the shell.
+
+Here are some example specifications:
+
+----------------------------------------------------
+# run "git credential-foo"
+foo
+
+# same as above, but pass an argument to the helper
+foo --bar=baz
+
+# the arguments are parsed by the shell, so use shell
+# quoting if necessary
+foo --bar="whitespace arg"
+
+# you can also use an absolute path, which will not use the git wrapper
+/path/to/my/helper --with-arguments
+
+# or you can specify your own shell snippet
+!f() { echo "password=`cat $HOME/.secret`"; }; f
+----------------------------------------------------
+
+Generally speaking, rule (3) above is the simplest for users to specify.
+Authors of credential helpers should make an effort to assist their
+users by naming their program "git-credential-$NAME", and putting it in
+the $PATH or $GIT_EXEC_PATH during installation, which will allow a user
+to enable it with `git config credential.helper $NAME`.
+
+When a helper is executed, it will have one "operation" argument
+appended to its command line, which is one of:
+
+`get`::
+
+	Return a matching credential, if any exists.
+
+`store`::
+
+	Store the credential, if applicable to the helper.
+
+`erase`::
+
+	Remove a matching credential, if any, from the helper's storage.
+
+The details of the credential will be provided on the helper's stdin
+stream. The credential is split into a set of named attributes.
+Attributes are provided to the helper, one per line. Each attribute is
+specified by a key-value pair, separated by an `=` (equals) sign,
+followed by a newline. The key may contain any bytes except `=`,
+newline, or NUL. The value may contain any bytes except newline or NUL.
+In both cases, all bytes are treated as-is (i.e., there is no quoting,
+and one cannot transmit a value with newline or NUL in it). The list of
+attributes is terminated by a blank line or end-of-file.
+
+Git will send the following attributes (but may not send all of
+them for a given credential; for example, a `host` attribute makes no
+sense when dealing with a non-network protocol):
+
+`protocol`::
+
+	The protocol over which the credential will be used (e.g.,
+	`https`).
+
+`host`::
+
+	The remote hostname for a network credential.
+
+`path`::
+
+	The path with which the credential will be used. E.g., for
+	accessing a remote https repository, this will be the
+	repository's path on the server.
+
+`username`::
+
+	The credential's username, if we already have one (e.g., from a
+	URL, from the user, or from a previously run helper).
+
+`password`::
+
+	The credential's password, if we are asking it to be stored.
+
+For a `get` operation, the helper should produce a list of attributes
+on stdout in the same format. A helper is free to produce a subset, or
+even no values at all if it has nothing useful to provide. Any provided
+attributes will overwrite those already known about by git.
+
+For a `store` or `erase` operation, the helper's output is ignored.
+If it fails to perform the requested operation, it may complain to
+stderr to inform the user. If it does not support the requested
+operation (e.g., a read-only store), it should silently ignore the
+request.
+
+If a helper receives any other operation, it should silently ignore the
+request. This leaves room for future operations to be added (older
+helpers will just ignore the new requests).
diff --git a/Makefile b/Makefile
index ed82320..d69f1dd 100644
--- a/Makefile
+++ b/Makefile
@@ -431,6 +431,7 @@ PROGRAM_OBJS += sh-i18n--envsubst.o
 PROGRAMS += $(patsubst %.o,git-%$X,$(PROGRAM_OBJS))
 
 TEST_PROGRAMS_NEED_X += test-chmtime
+TEST_PROGRAMS_NEED_X += test-credential
 TEST_PROGRAMS_NEED_X += test-ctype
 TEST_PROGRAMS_NEED_X += test-date
 TEST_PROGRAMS_NEED_X += test-delta
@@ -525,6 +526,7 @@ LIB_H += compat/win32/poll.h
 LIB_H += compat/win32/dirent.h
 LIB_H += connected.h
 LIB_H += convert.h
+LIB_H += credential.h
 LIB_H += csum-file.h
 LIB_H += decorate.h
 LIB_H += delta.h
@@ -611,6 +613,7 @@ LIB_OBJS += connect.o
 LIB_OBJS += connected.o
 LIB_OBJS += convert.o
 LIB_OBJS += copy.o
+LIB_OBJS += credential.o
 LIB_OBJS += csum-file.o
 LIB_OBJS += ctype.o
 LIB_OBJS += date.o
diff --git a/credential.c b/credential.c
new file mode 100644
index 0000000..86397f3
--- /dev/null
+++ b/credential.c
@@ -0,0 +1,234 @@
+#include "cache.h"
+#include "credential.h"
+#include "string-list.h"
+#include "run-command.h"
+
+void credential_init(struct credential *c)
+{
+	memset(c, 0, sizeof(*c));
+	c->helpers.strdup_strings = 1;
+}
+
+void credential_clear(struct credential *c)
+{
+	free(c->protocol);
+	free(c->host);
+	free(c->path);
+	free(c->username);
+	free(c->password);
+	string_list_clear(&c->helpers, 0);
+
+	credential_init(c);
+}
+
+static void credential_describe(struct credential *c, struct strbuf *out)
+{
+	if (!c->protocol)
+		return;
+	strbuf_addf(out, "%s://", c->protocol);
+	if (c->username && *c->username)
+		strbuf_addf(out, "%s@", c->username);
+	if (c->host)
+		strbuf_addstr(out, c->host);
+	if (c->path)
+		strbuf_addf(out, "/%s", c->path);
+}
+
+static char *credential_ask_one(const char *what, struct credential *c)
+{
+	struct strbuf desc = STRBUF_INIT;
+	struct strbuf prompt = STRBUF_INIT;
+	char *r;
+
+	credential_describe(c, &desc);
+	if (desc.len)
+		strbuf_addf(&prompt, "%s for '%s': ", what, desc.buf);
+	else
+		strbuf_addf(&prompt, "%s: ", what);
+
+	/* FIXME: for usernames, we should do something less magical that
+	 * actually echoes the characters. However, we need to read from
+	 * /dev/tty and not stdio, which is not portable (but getpass will do
+	 * it for us). http.c uses the same workaround. */
+	r = git_getpass(prompt.buf);
+
+	strbuf_release(&desc);
+	strbuf_release(&prompt);
+	return xstrdup(r);
+}
+
+static void credential_getpass(struct credential *c)
+{
+	if (!c->username)
+		c->username = credential_ask_one("Username", c);
+	if (!c->password)
+		c->password = credential_ask_one("Password", c);
+}
+
+int credential_read(struct credential *c, FILE *fp)
+{
+	struct strbuf line = STRBUF_INIT;
+
+	while (strbuf_getline(&line, fp, '\n') != EOF) {
+		char *key = line.buf;
+		char *value = strchr(key, '=');
+
+		if (!line.len)
+			break;
+
+		if (!value) {
+			warning("invalid credential line: %s", key);
+			strbuf_release(&line);
+			return -1;
+		}
+		*value++ = '\0';
+
+		if (!strcmp(key, "username")) {
+			free(c->username);
+			c->username = xstrdup(value);
+		} else if (!strcmp(key, "password")) {
+			free(c->password);
+			c->password = xstrdup(value);
+		} else if (!strcmp(key, "protocol")) {
+			free(c->protocol);
+			c->protocol = xstrdup(value);
+		} else if (!strcmp(key, "host")) {
+			free(c->host);
+			c->host = xstrdup(value);
+		} else if (!strcmp(key, "path")) {
+			free(c->path);
+			c->path = xstrdup(value);
+		}
+		/*
+		 * Ignore other lines; we don't know what they mean, but
+		 * this future-proofs us when later versions of git do
+		 * learn new lines, and the helpers are updated to match.
+		 */
+	}
+
+	strbuf_release(&line);
+	return 0;
+}
+
+static void credential_write_item(FILE *fp, const char *key, const char *value)
+{
+	if (!value)
+		return;
+	fprintf(fp, "%s=%s\n", key, value);
+}
+
+static void credential_write(const struct credential *c, FILE *fp)
+{
+	credential_write_item(fp, "protocol", c->protocol);
+	credential_write_item(fp, "host", c->host);
+	credential_write_item(fp, "path", c->path);
+	credential_write_item(fp, "username", c->username);
+	credential_write_item(fp, "password", c->password);
+}
+
+static int run_credential_helper(struct credential *c,
+				 const char *cmd,
+				 int want_output)
+{
+	struct child_process helper;
+	const char *argv[] = { NULL, NULL };
+	FILE *fp;
+
+	memset(&helper, 0, sizeof(helper));
+	argv[0] = cmd;
+	helper.argv = argv;
+	helper.use_shell = 1;
+	helper.in = -1;
+	if (want_output)
+		helper.out = -1;
+	else
+		helper.no_stdout = 1;
+
+	if (start_command(&helper) < 0)
+		return -1;
+
+	fp = xfdopen(helper.in, "w");
+	credential_write(c, fp);
+	fclose(fp);
+
+	if (want_output) {
+		int r;
+		fp = xfdopen(helper.out, "r");
+		r = credential_read(c, fp);
+		fclose(fp);
+		if (r < 0) {
+			finish_command(&helper);
+			return -1;
+		}
+	}
+
+	if (finish_command(&helper))
+		return -1;
+	return 0;
+}
+
+static int credential_do(struct credential *c, const char *helper,
+			 const char *operation)
+{
+	struct strbuf cmd = STRBUF_INIT;
+	int r;
+
+	if (helper[0] == '!')
+		strbuf_addstr(&cmd, helper + 1);
+	else if (is_absolute_path(helper))
+		strbuf_addstr(&cmd, helper);
+	else
+		strbuf_addf(&cmd, "git credential-%s", helper);
+
+	strbuf_addf(&cmd, " %s", operation);
+	r = run_credential_helper(c, cmd.buf, !strcmp(operation, "get"));
+
+	strbuf_release(&cmd);
+	return r;
+}
+
+void credential_fill(struct credential *c)
+{
+	int i;
+
+	if (c->username && c->password)
+		return;
+
+	for (i = 0; i < c->helpers.nr; i++) {
+		credential_do(c, c->helpers.items[i].string, "get");
+		if (c->username && c->password)
+			return;
+	}
+
+	credential_getpass(c);
+	if (!c->username && !c->password)
+		die("unable to get password from user");
+}
+
+void credential_approve(struct credential *c)
+{
+	int i;
+
+	if (c->approved)
+		return;
+	if (!c->username || !c->password)
+		return;
+
+	for (i = 0; i < c->helpers.nr; i++)
+		credential_do(c, c->helpers.items[i].string, "store");
+	c->approved = 1;
+}
+
+void credential_reject(struct credential *c)
+{
+	int i;
+
+	for (i = 0; i < c->helpers.nr; i++)
+		credential_do(c, c->helpers.items[i].string, "erase");
+
+	free(c->username);
+	c->username = NULL;
+	free(c->password);
+	c->password = NULL;
+	c->approved = 0;
+}
diff --git a/credential.h b/credential.h
new file mode 100644
index 0000000..2ea7d49
--- /dev/null
+++ b/credential.h
@@ -0,0 +1,28 @@
+#ifndef CREDENTIAL_H
+#define CREDENTIAL_H
+
+#include "string-list.h"
+
+struct credential {
+	struct string_list helpers;
+	unsigned approved:1;
+
+	char *username;
+	char *password;
+	char *protocol;
+	char *host;
+	char *path;
+};
+
+#define CREDENTIAL_INIT { STRING_LIST_INIT_DUP }
+
+void credential_init(struct credential *);
+void credential_clear(struct credential *);
+
+void credential_fill(struct credential *);
+void credential_approve(struct credential *);
+void credential_reject(struct credential *);
+
+int credential_read(struct credential *, FILE *);
+
+#endif /* CREDENTIAL_H */
diff --git a/t/lib-credential.sh b/t/lib-credential.sh
new file mode 100755
index 0000000..54ae1f4
--- /dev/null
+++ b/t/lib-credential.sh
@@ -0,0 +1,33 @@
+#!/bin/sh
+
+# Try a set of credential helpers; the expected stdin,
+# stdout and stderr should be provided on stdin,
+# separated by "--".
+check() {
+	read_chunk >stdin &&
+	read_chunk >expect-stdout &&
+	read_chunk >expect-stderr &&
+	test-credential "$@" <stdin >stdout 2>stderr &&
+	test_cmp expect-stdout stdout &&
+	test_cmp expect-stderr stderr
+}
+
+read_chunk() {
+	while read line; do
+		case "$line" in
+		--) break ;;
+		*) echo "$line" ;;
+		esac
+	done
+}
+
+
+cat >askpass <<\EOF
+#!/bin/sh
+echo >&2 askpass: $*
+what=`echo $1 | cut -d" " -f1 | tr A-Z a-z | tr -cd a-z`
+echo "askpass-$what"
+EOF
+chmod +x askpass
+GIT_ASKPASS="$PWD/askpass"
+export GIT_ASKPASS
diff --git a/t/t0300-credentials.sh b/t/t0300-credentials.sh
new file mode 100755
index 0000000..81a455f
--- /dev/null
+++ b/t/t0300-credentials.sh
@@ -0,0 +1,195 @@
+#!/bin/sh
+
+test_description='basic credential helper tests'
+. ./test-lib.sh
+. "$TEST_DIRECTORY"/lib-credential.sh
+
+test_expect_success 'setup helper scripts' '
+	cat >dump <<-\EOF &&
+	whoami=`echo $0 | sed s/.*git-credential-//`
+	echo >&2 "$whoami: $*"
+	while IFS== read key value; do
+		echo >&2 "$whoami: $key=$value"
+		eval "$key=$value"
+	done
+	EOF
+
+	cat >git-credential-useless <<-\EOF &&
+	#!/bin/sh
+	. ./dump
+	exit 0
+	EOF
+	chmod +x git-credential-useless &&
+
+	cat >git-credential-verbatim <<-\EOF &&
+	#!/bin/sh
+	user=$1; shift
+	pass=$1; shift
+	. ./dump
+	test -z "$user" || echo username=$user
+	test -z "$pass" || echo password=$pass
+	EOF
+	chmod +x git-credential-verbatim &&
+
+	PATH="$PWD:$PATH"
+'
+
+test_expect_success 'credential_fill invokes helper' '
+	check fill "verbatim foo bar" <<-\EOF
+	--
+	username=foo
+	password=bar
+	--
+	verbatim: get
+	EOF
+'
+
+test_expect_success 'credential_fill invokes multiple helpers' '
+	check fill useless "verbatim foo bar" <<-\EOF
+	--
+	username=foo
+	password=bar
+	--
+	useless: get
+	verbatim: get
+	EOF
+'
+
+test_expect_success 'credential_fill stops when we get a full response' '
+	check fill "verbatim one two" "verbatim three four" <<-\EOF
+	--
+	username=one
+	password=two
+	--
+	verbatim: get
+	EOF
+'
+
+test_expect_success 'credential_fill continues through partial response' '
+	check fill "verbatim one \"\"" "verbatim two three" <<-\EOF
+	--
+	username=two
+	password=three
+	--
+	verbatim: get
+	verbatim: get
+	verbatim: username=one
+	EOF
+'
+
+test_expect_success 'credential_fill passes along metadata' '
+	check fill "verbatim one two" <<-\EOF
+	protocol=ftp
+	host=example.com
+	path=foo.git
+	--
+	username=one
+	password=two
+	--
+	verbatim: get
+	verbatim: protocol=ftp
+	verbatim: host=example.com
+	verbatim: path=foo.git
+	EOF
+'
+
+test_expect_success 'credential_approve calls all helpers' '
+	check approve useless "verbatim one two" <<-\EOF
+	username=foo
+	password=bar
+	--
+	--
+	useless: store
+	useless: username=foo
+	useless: password=bar
+	verbatim: store
+	verbatim: username=foo
+	verbatim: password=bar
+	EOF
+'
+
+test_expect_success 'do not bother storing password-less credential' '
+	check approve useless <<-\EOF
+	username=foo
+	--
+	--
+	EOF
+'
+
+
+test_expect_success 'credential_reject calls all helpers' '
+	check reject useless "verbatim one two" <<-\EOF
+	username=foo
+	password=bar
+	--
+	--
+	useless: erase
+	useless: username=foo
+	useless: password=bar
+	verbatim: erase
+	verbatim: username=foo
+	verbatim: password=bar
+	EOF
+'
+
+test_expect_success 'usernames can be preserved' '
+	check fill "verbatim \"\" three" <<-\EOF
+	username=one
+	--
+	username=one
+	password=three
+	--
+	verbatim: get
+	verbatim: username=one
+	EOF
+'
+
+test_expect_success 'usernames can be overridden' '
+	check fill "verbatim two three" <<-\EOF
+	username=one
+	--
+	username=two
+	password=three
+	--
+	verbatim: get
+	verbatim: username=one
+	EOF
+'
+
+test_expect_success 'do not bother completing already-full credential' '
+	check fill "verbatim three four" <<-\EOF
+	username=one
+	password=two
+	--
+	username=one
+	password=two
+	--
+	EOF
+'
+
+# We can't test the basic terminal password prompt here because
+# getpass() tries too hard to find the real terminal. But if our
+# askpass helper is run, we know the internal getpass is working.
+test_expect_success 'empty helper list falls back to internal getpass' '
+	check fill <<-\EOF
+	--
+	username=askpass-username
+	password=askpass-password
+	--
+	askpass: Username:
+	askpass: Password:
+	EOF
+'
+
+test_expect_success 'internal getpass does not ask for known username' '
+	check fill <<-\EOF
+	username=foo
+	--
+	username=foo
+	password=askpass-password
+	--
+	askpass: Password:
+	EOF
+'
+
+test_done
diff --git a/test-credential.c b/test-credential.c
new file mode 100644
index 0000000..dee200e
--- /dev/null
+++ b/test-credential.c
@@ -0,0 +1,38 @@
+#include "cache.h"
+#include "credential.h"
+#include "string-list.h"
+
+static const char usage_msg[] =
+"test-credential <fill|approve|reject> [helper...]";
+
+int main(int argc, const char **argv)
+{
+	const char *op;
+	struct credential c = CREDENTIAL_INIT;
+	int i;
+
+	op = argv[1];
+	if (!op)
+		usage(usage_msg);
+	for (i = 2; i < argc; i++)
+		string_list_append(&c.helpers, argv[i]);
+
+	if (credential_read(&c, stdin) < 0)
+		die("unable to read credential from stdin");
+
+	if (!strcmp(op, "fill")) {
+		credential_fill(&c);
+		if (c.username)
+			printf("username=%s\n", c.username);
+		if (c.password)
+			printf("password=%s\n", c.password);
+	}
+	else if (!strcmp(op, "approve"))
+		credential_approve(&c);
+	else if (!strcmp(op, "reject"))
+		credential_reject(&c);
+	else
+		usage(usage_msg);
+
+	return 0;
+}
-- 
1.7.8.rc2.40.gaf387

Re: [PATCHv3 03/13] introduce credentials API

[Jakub Narebski]

Jeff King <peff@peff.net> writes:

> There are a few places in git that need to get a username
> and password credential from the user; the most notable one
> is HTTP authentication for smart-http pushing.

A question: does it work also for access via SSH, either without
public key set up (i.e. 'keyboard-interactive'), or with encrypted
private key without ssh-agent set up?

It would probably require URL i.e. ssh://git.example.com/srv/scm/repo.git
or git+ssh://git.example.com/srv/scm/repo.git and not scp-like
address i.e. user@git.example.com:/srv/scm/repo.git, isn't it?

-- 
Jakub Narębski

Re: [PATCHv3 03/13] introduce credentials API

[Jeff King]

On Sat, Dec 10, 2011 at 03:43:01AM -0800, Jakub Narebski wrote:

> Jeff King <peff@peff.net> writes:
> 
> > There are a few places in git that need to get a username
> > and password credential from the user; the most notable one
> > is HTTP authentication for smart-http pushing.
> 
> A question: does it work also for access via SSH, either without
> public key set up (i.e. 'keyboard-interactive'), or with encrypted
> private key without ssh-agent set up?

No. ssh handles its own password querying, and contacts the user
directly via the terminal. And there's not much point in using a
password helper with ssh; if you don't want to type your password, set
up a key and use ssh-agent.

> It would probably require URL i.e. ssh://git.example.com/srv/scm/repo.git
> or git+ssh://git.example.com/srv/scm/repo.git and not scp-like
> address i.e. user@git.example.com:/srv/scm/repo.git, isn't it?

It's not a matter of recognizing the URL; it's that we hand off the
authentication problem to ssh, which takes care of it entirely itself.

-Peff

[PATCHv3 04/13] credential: add function for parsing url components

[Jeff King]

All of the components of a credential struct can be found in
a URL.  For example, the URL:

  http://foo:bar@example.com/repo.git

contains:

  protocol=http
  host=example.com
  path=repo.git
  username=foo
  password=bar

We want to be able to turn URLs into broken-down credential
structs so that we know two things:

  1. Which parts of the username/password we still need

  2. What the context of the request is (for prompting or
     as a key for storing credentials).

This code is based on http_auth_init in http.c, but needed a
few modifications in order to get all of the components that
the credential object is interested in.

Once the http code is switched over to the credential API,
then http_auth_init can just go away.

Signed-off-by: Jeff King <peff@peff.net>
---
 Documentation/technical/api-credentials.txt |    4 ++
 credential.c                                |   52 +++++++++++++++++++++++++++
 credential.h                                |    1 +
 3 files changed, 57 insertions(+), 0 deletions(-)

diff --git a/Documentation/technical/api-credentials.txt b/Documentation/technical/api-credentials.txt
index f624aef..21ca6a2 100644
--- a/Documentation/technical/api-credentials.txt
+++ b/Documentation/technical/api-credentials.txt
@@ -67,6 +67,10 @@ Functions
 	that they may store the result to be used again.  Any errors
 	from helpers are ignored.
 
+`credential_from_url`::
+
+	Parse a URL into broken-down credential fields.
+
 Example
 -------
 
diff --git a/credential.c b/credential.c
index 86397f3..c349b9a 100644
--- a/credential.c
+++ b/credential.c
@@ -2,6 +2,7 @@
 #include "credential.h"
 #include "string-list.h"
 #include "run-command.h"
+#include "url.h"
 
 void credential_init(struct credential *c)
 {
@@ -232,3 +233,54 @@ void credential_reject(struct credential *c)
 	c->password = NULL;
 	c->approved = 0;
 }
+
+void credential_from_url(struct credential *c, const char *url)
+{
+	const char *at, *colon, *cp, *slash, *host, *proto_end;
+
+	credential_clear(c);
+
+	/*
+	 * Match one of:
+	 *   (1) proto://<host>/...
+	 *   (2) proto://<user>@<host>/...
+	 *   (3) proto://<user>:<pass>@<host>/...
+	 */
+	proto_end = strstr(url, "://");
+	if (!proto_end)
+		return;
+	cp = proto_end + 3;
+	at = strchr(cp, '@');
+	colon = strchr(cp, ':');
+	slash = strchrnul(cp, '/');
+
+	if (!at || slash <= at) {
+		/* Case (1) */
+		host = cp;
+	}
+	else if (!colon || at <= colon) {
+		/* Case (2) */
+		c->username = url_decode_mem(cp, at - cp);
+		host = at + 1;
+	} else {
+		/* Case (3) */
+		c->username = url_decode_mem(cp, colon - cp);
+		c->password = url_decode_mem(colon + 1, at - (colon + 1));
+		host = at + 1;
+	}
+
+	if (proto_end - url > 0)
+		c->protocol = xmemdupz(url, proto_end - url);
+	if (slash - host > 0)
+		c->host = url_decode_mem(host, slash - host);
+	/* Trim leading and trailing slashes from path */
+	while (*slash == '/')
+		slash++;
+	if (*slash) {
+		char *p;
+		c->path = url_decode(slash);
+		p = c->path + strlen(c->path) - 1;
+		while (p > c->path && *p == '/')
+			*p-- = '\0';
+	}
+}
diff --git a/credential.h b/credential.h
index 2ea7d49..8a6d162 100644
--- a/credential.h
+++ b/credential.h
@@ -24,5 +24,6 @@ struct credential {
 void credential_reject(struct credential *);
 
 int credential_read(struct credential *, FILE *);
+void credential_from_url(struct credential *, const char *url);
 
 #endif /* CREDENTIAL_H */
-- 
1.7.8.rc2.40.gaf387

[PATCHv3 05/13] http: use credential API to get passwords

[Jeff King]

This patch converts the http code to use the new credential
API, both for http authentication as well as for getting
certificate passwords.

Most of the code change is simply variable naming (the
passwords are now contained inside the credential struct)
or deletion of obsolete code (the credential code handles
URL parsing and prompting for us).

The behavior should be the same, with one exception: the
credential code will prompt with a description based on the
credential components. Therefore, the old prompt of:

  Username for 'example.com':
  Password for 'example.com':

now looks like:

  Username for 'https://example.com/repo.git':
  Password for 'https://user@example.com/repo.git':

Note that we include more information in each line,
specifically:

  1. We now include the protocol. While more noisy, this is
     an important part of knowing what you are accessing
     (especially if you care about http vs https).

  2. We include the username in the password prompt. This is
     not a big deal when you have just been prompted for it,
     but the username may also come from the remote's URL
     (and after future patches, from configuration or
     credential helpers).  In that case, it's a nice
     reminder of the user for which you're giving the
     password.

  3. We include the path component of the URL. In many
     cases, the user won't care about this and it's simply
     noise (i.e., they'll use the same credential for a
     whole site). However, that is part of a larger
     question, which is whether path components should be
     part of credential context, both for prompting and for
     lookup by storage helpers. That issue will be addressed
     as a whole in a future patch.

Similarly, for unlocking certificates, we used to say:

  Certificate Password for 'example.com':

and we now say:

  Password for 'cert:///path/to/certificate':

Showing the path to the client certificate makes more sense,
as that is what you are unlocking, not "example.com".

Signed-off-by: Jeff King <peff@peff.net>
---
 http.c                |  113 +++++++++++--------------------------------------
 t/t5550-http-fetch.sh |   38 ++++++++++++-----
 2 files changed, 52 insertions(+), 99 deletions(-)

diff --git a/http.c b/http.c
index 44fcc4d..8e72664 100644
--- a/http.c
+++ b/http.c
@@ -3,6 +3,7 @@
 #include "sideband.h"
 #include "run-command.h"
 #include "url.h"
+#include "credential.h"
 
 int active_requests;
 int http_is_verbose;
@@ -41,7 +42,7 @@
 static int curl_ftp_no_epsv;
 static const char *curl_http_proxy;
 static const char *curl_cookie_file;
-static char *user_name, *user_pass, *description;
+static struct credential http_auth = CREDENTIAL_INIT;
 static const char *user_agent;
 
 #if LIBCURL_VERSION_NUM >= 0x071700
@@ -52,7 +53,7 @@
 #define CURLOPT_KEYPASSWD CURLOPT_SSLCERTPASSWD
 #endif
 
-static char *ssl_cert_password;
+static struct credential cert_auth = CREDENTIAL_INIT;
 static int ssl_cert_password_required;
 
 static struct curl_slist *pragma_header;
@@ -136,27 +137,6 @@ static void process_curl_messages(void)
 }
 #endif
 
-static char *git_getpass_with_description(const char *what, const char *desc)
-{
-	struct strbuf prompt = STRBUF_INIT;
-	char *r;
-
-	if (desc)
-		strbuf_addf(&prompt, "%s for '%s': ", what, desc);
-	else
-		strbuf_addf(&prompt, "%s: ", what);
-	/*
-	 * NEEDSWORK: for usernames, we should do something less magical that
-	 * actually echoes the characters. However, we need to read from
-	 * /dev/tty and not stdio, which is not portable (but getpass will do
-	 * it for us). http.c uses the same workaround.
-	 */
-	r = git_getpass(prompt.buf);
-
-	strbuf_release(&prompt);
-	return xstrdup(r);
-}
-
 static int http_options(const char *var, const char *value, void *cb)
 {
 	if (!strcmp("http.sslverify", var)) {
@@ -229,11 +209,11 @@ static int http_options(const char *var, const char *value, void *cb)
 
 static void init_curl_http_auth(CURL *result)
 {
-	if (user_name) {
+	if (http_auth.username) {
 		struct strbuf up = STRBUF_INIT;
-		if (!user_pass)
-			user_pass = xstrdup(git_getpass_with_description("Password", description));
-		strbuf_addf(&up, "%s:%s", user_name, user_pass);
+		credential_fill(&http_auth);
+		strbuf_addf(&up, "%s:%s",
+			    http_auth.username, http_auth.password);
 		curl_easy_setopt(result, CURLOPT_USERPWD,
 				 strbuf_detach(&up, NULL));
 	}
@@ -241,18 +221,14 @@ static void init_curl_http_auth(CURL *result)
 
 static int has_cert_password(void)
 {
-	if (ssl_cert_password != NULL)
-		return 1;
 	if (ssl_cert == NULL || ssl_cert_password_required != 1)
 		return 0;
-	/* Only prompt the user once. */
-	ssl_cert_password_required = -1;
-	ssl_cert_password = git_getpass_with_description("Certificate Password", description);
-	if (ssl_cert_password != NULL) {
-		ssl_cert_password = xstrdup(ssl_cert_password);
-		return 1;
-	} else
-		return 0;
+	if (!cert_auth.password) {
+		cert_auth.protocol = xstrdup("cert");
+		cert_auth.path = xstrdup(ssl_cert);
+		credential_fill(&cert_auth);
+	}
+	return 1;
 }
 
 static CURL *get_curl_handle(void)
@@ -279,7 +255,7 @@ static int has_cert_password(void)
 	if (ssl_cert != NULL)
 		curl_easy_setopt(result, CURLOPT_SSLCERT, ssl_cert);
 	if (has_cert_password())
-		curl_easy_setopt(result, CURLOPT_KEYPASSWD, ssl_cert_password);
+		curl_easy_setopt(result, CURLOPT_KEYPASSWD, cert_auth.password);
 #if LIBCURL_VERSION_NUM >= 0x070903
 	if (ssl_key != NULL)
 		curl_easy_setopt(result, CURLOPT_SSLKEY, ssl_key);
@@ -321,42 +297,6 @@ static int has_cert_password(void)
 	return result;
 }
 
-static void http_auth_init(const char *url)
-{
-	const char *at, *colon, *cp, *slash, *host;
-
-	cp = strstr(url, "://");
-	if (!cp)
-		return;
-
-	/*
-	 * Ok, the URL looks like "proto://something".  Which one?
-	 * "proto://<user>:<pass>@<host>/...",
-	 * "proto://<user>@<host>/...", or just
-	 * "proto://<host>/..."?
-	 */
-	cp += 3;
-	at = strchr(cp, '@');
-	colon = strchr(cp, ':');
-	slash = strchrnul(cp, '/');
-	if (!at || slash <= at) {
-		/* No credentials, but we may have to ask for some later */
-		host = cp;
-	}
-	else if (!colon || at <= colon) {
-		/* Only username */
-		user_name = url_decode_mem(cp, at - cp);
-		user_pass = NULL;
-		host = at + 1;
-	} else {
-		user_name = url_decode_mem(cp, colon - cp);
-		user_pass = url_decode_mem(colon + 1, at - (colon + 1));
-		host = at + 1;
-	}
-
-	description = url_decode_mem(host, slash - host);
-}
-
 static void set_from_env(const char **var, const char *envname)
 {
 	const char *val = getenv(envname);
@@ -429,7 +369,7 @@ void http_init(struct remote *remote, const char *url)
 		curl_ftp_no_epsv = 1;
 
 	if (url) {
-		http_auth_init(url);
+		credential_from_url(&http_auth, url);
 		if (!ssl_cert_password_required &&
 		    getenv("GIT_SSL_CERT_PASSWORD_PROTECTED") &&
 		    !prefixcmp(url, "https://"))
@@ -478,10 +418,10 @@ void http_cleanup(void)
 		curl_http_proxy = NULL;
 	}
 
-	if (ssl_cert_password != NULL) {
-		memset(ssl_cert_password, 0, strlen(ssl_cert_password));
-		free(ssl_cert_password);
-		ssl_cert_password = NULL;
+	if (cert_auth.password != NULL) {
+		memset(cert_auth.password, 0, strlen(cert_auth.password));
+		free(cert_auth.password);
+		cert_auth.password = NULL;
 	}
 	ssl_cert_password_required = 0;
 }
@@ -837,17 +777,11 @@ static int http_request(const char *url, void *result, int target, int options)
 		else if (missing_target(&results))
 			ret = HTTP_MISSING_TARGET;
 		else if (results.http_code == 401) {
-			if (user_name && user_pass) {
+			if (http_auth.username && http_auth.password) {
+				credential_reject(&http_auth);
 				ret = HTTP_NOAUTH;
 			} else {
-				/*
-				 * git_getpass is needed here because its very likely stdin/stdout are
-				 * pipes to our parent process.  So we instead need to use /dev/tty,
-				 * but that is non-portable.  Using git_getpass() can at least be stubbed
-				 * on other platforms with a different implementation if/when necessary.
-				 */
-				if (!user_name)
-					user_name = xstrdup(git_getpass_with_description("Username", description));
+				credential_fill(&http_auth);
 				init_curl_http_auth(slot->curl);
 				ret = HTTP_REAUTH;
 			}
@@ -866,6 +800,9 @@ static int http_request(const char *url, void *result, int target, int options)
 	curl_slist_free_all(headers);
 	strbuf_release(&buf);
 
+	if (ret == HTTP_OK)
+		credential_approve(&http_auth);
+
 	return ret;
 }
 
diff --git a/t/t5550-http-fetch.sh b/t/t5550-http-fetch.sh
index 3d6e871..398a2d2 100755
--- a/t/t5550-http-fetch.sh
+++ b/t/t5550-http-fetch.sh
@@ -49,40 +49,56 @@ test_expect_success 'setup askpass helpers' '
 	EOF
 	chmod +x askpass &&
 	GIT_ASKPASS="$PWD/askpass" &&
-	export GIT_ASKPASS &&
-	>askpass-expect-none &&
-	echo "askpass: Password for '\''$HTTPD_DEST'\'': " >askpass-expect-pass &&
-	{ echo "askpass: Username for '\''$HTTPD_DEST'\'': " &&
-	  cat askpass-expect-pass
-	} >askpass-expect-both
-'
+	export GIT_ASKPASS
+'
+
+expect_askpass() {
+	dest=$HTTPD_DEST/auth/repo.git
+	{
+		case "$1" in
+		none)
+			;;
+		pass)
+			echo "askpass: Password for 'http://$2@$dest': "
+			;;
+		both)
+			echo "askpass: Username for 'http://$dest': "
+			echo "askpass: Password for 'http://$2@$dest': "
+			;;
+		*)
+			false
+			;;
+		esac
+	} >askpass-expect &&
+	test_cmp askpass-expect askpass-query
+}
 
 test_expect_success 'cloning password-protected repository can fail' '
 	>askpass-query &&
 	echo wrong >askpass-response &&
 	test_must_fail git clone "$HTTPD_URL/auth/repo.git" clone-auth-fail &&
-	test_cmp askpass-expect-both askpass-query
+	expect_askpass both wrong
 '
 
 test_expect_success 'http auth can use user/pass in URL' '
 	>askpass-query &&
 	echo wrong >askpass-response &&
 	git clone "$HTTPD_URL_USER_PASS/auth/repo.git" clone-auth-none &&
-	test_cmp askpass-expect-none askpass-query
+	expect_askpass none
 '
 
 test_expect_success 'http auth can use just user in URL' '
 	>askpass-query &&
 	echo user@host >askpass-response &&
 	git clone "$HTTPD_URL_USER/auth/repo.git" clone-auth-pass &&
-	test_cmp askpass-expect-pass askpass-query
+	expect_askpass pass user@host
 '
 
 test_expect_success 'http auth can request both user and pass' '
 	>askpass-query &&
 	echo user@host >askpass-response &&
 	git clone "$HTTPD_URL/auth/repo.git" clone-auth-both &&
-	test_cmp askpass-expect-both askpass-query
+	expect_askpass both user@host
 '
 
 test_expect_success 'fetch changes via http' '
-- 
1.7.8.rc2.40.gaf387

[PATCHv3 06/13] credential: apply helper config

[Jeff King]

The functionality for credential storage helpers is already
there; we just need to give the users a way to turn it on.
This patch provides a "credential.helper" configuration
variable which allows the user to provide one or more helper
strings.

Rather than simply matching credential.helper, we will also
compare URLs in subsection headings to the current context.
This means you can apply configuration to a subset of
credentials. For example:

  [credential "https://example.com"]
	helper = foo

would match a request for "https://example.com/foo.git", but
not one for "https://kernel.org/foo.git".

This is overkill for the "helper" variable, since users are
unlikely to want different helpers for different sites (and
since helpers run arbitrary code, they could do the matching
themselves anyway).

However, future patches will add new config variables where
this extra feature will be more useful.

Signed-off-by: Jeff King <peff@peff.net>
---
 credential.c           |   61 ++++++++++++++++++++++++++++++++++++++++++++++++
 credential.h           |    5 +++-
 t/t0300-credentials.sh |   42 +++++++++++++++++++++++++++++++++
 t/t5550-http-fetch.sh  |   12 +++++++++
 4 files changed, 119 insertions(+), 1 deletions(-)

diff --git a/credential.c b/credential.c
index c349b9a..96be1c2 100644
--- a/credential.c
+++ b/credential.c
@@ -22,6 +22,61 @@ void credential_clear(struct credential *c)
 	credential_init(c);
 }
 
+int credential_match(const struct credential *want,
+		     const struct credential *have)
+{
+#define CHECK(x) (!want->x || (have->x && !strcmp(want->x, have->x)))
+	return CHECK(protocol) &&
+	       CHECK(host) &&
+	       CHECK(path) &&
+	       CHECK(username);
+#undef CHECK
+}
+
+static int credential_config_callback(const char *var, const char *value,
+				      void *data)
+{
+	struct credential *c = data;
+	const char *key, *dot;
+
+	key = skip_prefix(var, "credential.");
+	if (!key)
+		return 0;
+
+	if (!value)
+		return config_error_nonbool(var);
+
+	dot = strrchr(key, '.');
+	if (dot) {
+		struct credential want = CREDENTIAL_INIT;
+		char *url = xmemdupz(key, dot - key);
+		int matched;
+
+		credential_from_url(&want, url);
+		matched = credential_match(&want, c);
+
+		credential_clear(&want);
+		free(url);
+
+		if (!matched)
+			return 0;
+		key = dot + 1;
+	}
+
+	if (!strcmp(key, "helper"))
+		string_list_append(&c->helpers, value);
+
+	return 0;
+}
+
+static void credential_apply_config(struct credential *c)
+{
+	if (c->configured)
+		return;
+	git_config(credential_config_callback, c);
+	c->configured = 1;
+}
+
 static void credential_describe(struct credential *c, struct strbuf *out)
 {
 	if (!c->protocol)
@@ -195,6 +250,8 @@ void credential_fill(struct credential *c)
 	if (c->username && c->password)
 		return;
 
+	credential_apply_config(c);
+
 	for (i = 0; i < c->helpers.nr; i++) {
 		credential_do(c, c->helpers.items[i].string, "get");
 		if (c->username && c->password)
@@ -215,6 +272,8 @@ void credential_approve(struct credential *c)
 	if (!c->username || !c->password)
 		return;
 
+	credential_apply_config(c);
+
 	for (i = 0; i < c->helpers.nr; i++)
 		credential_do(c, c->helpers.items[i].string, "store");
 	c->approved = 1;
@@ -224,6 +283,8 @@ void credential_reject(struct credential *c)
 {
 	int i;
 
+	credential_apply_config(c);
+
 	for (i = 0; i < c->helpers.nr; i++)
 		credential_do(c, c->helpers.items[i].string, "erase");
 
diff --git a/credential.h b/credential.h
index 8a6d162..e504272 100644
--- a/credential.h
+++ b/credential.h
@@ -5,7 +5,8 @@
 
 struct credential {
 	struct string_list helpers;
-	unsigned approved:1;
+	unsigned approved:1,
+		 configured:1;
 
 	char *username;
 	char *password;
@@ -25,5 +26,7 @@ struct credential {
 
 int credential_read(struct credential *, FILE *);
 void credential_from_url(struct credential *, const char *url);
+int credential_match(const struct credential *have,
+		     const struct credential *want);
 
 #endif /* CREDENTIAL_H */
diff --git a/t/t0300-credentials.sh b/t/t0300-credentials.sh
index 81a455f..42d0f5b 100755
--- a/t/t0300-credentials.sh
+++ b/t/t0300-credentials.sh
@@ -192,4 +192,46 @@ test_expect_success 'internal getpass does not ask for known username' '
 	EOF
 '
 
+HELPER="!f() {
+		cat >/dev/null
+		echo username=foo
+		echo password=bar
+	}; f"
+test_expect_success 'respect configured credentials' '
+	test_config credential.helper "$HELPER" &&
+	check fill <<-\EOF
+	--
+	username=foo
+	password=bar
+	--
+	EOF
+'
+
+test_expect_success 'match configured credential' '
+	test_config credential.https://example.com.helper "$HELPER" &&
+	check fill <<-\EOF
+	protocol=https
+	host=example.com
+	path=repo.git
+	--
+	username=foo
+	password=bar
+	--
+	EOF
+'
+
+test_expect_success 'do not match configured credential' '
+	test_config credential.https://foo.helper "$HELPER" &&
+	check fill <<-\EOF
+	protocol=https
+	host=bar
+	--
+	username=askpass-username
+	password=askpass-password
+	--
+	askpass: Username for '\''https://bar'\'':
+	askpass: Password for '\''https://askpass-username@bar'\'':
+	EOF
+'
+
 test_done
diff --git a/t/t5550-http-fetch.sh b/t/t5550-http-fetch.sh
index 398a2d2..c59908f 100755
--- a/t/t5550-http-fetch.sh
+++ b/t/t5550-http-fetch.sh
@@ -101,6 +101,18 @@ test_expect_success 'http auth can request both user and pass' '
 	expect_askpass both user@host
 '
 
+test_expect_success 'http auth respects credential helper config' '
+	test_config_global credential.helper "!f() {
+		cat >/dev/null
+		echo username=user@host
+		echo password=user@host
+	}; f" &&
+	>askpass-query &&
+	echo wrong >askpass-response &&
+	git clone "$HTTPD_URL/auth/repo.git" clone-auth-helper &&
+	expect_askpass none
+'
+
 test_expect_success 'fetch changes via http' '
 	echo content >>file &&
 	git commit -a -m two &&
-- 
1.7.8.rc2.40.gaf387

[PATCHv3 07/13] credential: add credential.*.username

[Jeff King]

Credential helpers can help users avoid having to type their
username and password over and over. However, some users may
not want a helper for their password, or they may be running
a helper which caches for a short time. In this case, it is
convenient to provide the non-secret username portion of
their credential via config.

Signed-off-by: Jeff King <peff@peff.net>
---
 credential.c           |    4 ++++
 t/t0300-credentials.sh |   13 +++++++++++++
 t/t5550-http-fetch.sh  |   16 ++++++++++++++++
 3 files changed, 33 insertions(+), 0 deletions(-)

diff --git a/credential.c b/credential.c
index 96be1c2..3c17ea1 100644
--- a/credential.c
+++ b/credential.c
@@ -65,6 +65,10 @@ static int credential_config_callback(const char *var, const char *value,
 
 	if (!strcmp(key, "helper"))
 		string_list_append(&c->helpers, value);
+	else if (!strcmp(key, "username")) {
+		if (!c->username)
+			c->username = xstrdup(value);
+	}
 
 	return 0;
 }
diff --git a/t/t0300-credentials.sh b/t/t0300-credentials.sh
index 42d0f5b..53e94bc 100755
--- a/t/t0300-credentials.sh
+++ b/t/t0300-credentials.sh
@@ -234,4 +234,17 @@ test_expect_success 'do not match configured credential' '
 	EOF
 '
 
+test_expect_success 'pull username from config' '
+	test_config credential.https://example.com.username foo &&
+	check fill <<-\EOF
+	protocol=https
+	host=example.com
+	--
+	username=foo
+	password=askpass-password
+	--
+	askpass: Password for '\''https://foo@example.com'\'':
+	EOF
+'
+
 test_done
diff --git a/t/t5550-http-fetch.sh b/t/t5550-http-fetch.sh
index c59908f..3262f90 100755
--- a/t/t5550-http-fetch.sh
+++ b/t/t5550-http-fetch.sh
@@ -113,6 +113,22 @@ test_expect_success 'http auth respects credential helper config' '
 	expect_askpass none
 '
 
+test_expect_success 'http auth can get username from config' '
+	test_config_global "credential.$HTTPD_URL.username" user@host &&
+	>askpass-query &&
+	echo user@host >askpass-response &&
+	git clone "$HTTPD_URL/auth/repo.git" clone-auth-user &&
+	expect_askpass pass user@host
+'
+
+test_expect_success 'configured username does not override URL' '
+	test_config_global "credential.$HTTPD_URL.username" wrong &&
+	>askpass-query &&
+	echo user@host >askpass-response &&
+	git clone "$HTTPD_URL_USER/auth/repo.git" clone-auth-user2 &&
+	expect_askpass pass user@host
+'
+
 test_expect_success 'fetch changes via http' '
 	echo content >>file &&
 	git commit -a -m two &&
-- 
1.7.8.rc2.40.gaf387

[PATCHv3 08/13] credential: make relevance of http path configurable

[Jeff King]

When parsing a URL into a credential struct, we carefully
record each part of the URL, including the path on the
remote host, and use the result as part of the credential
context.

This had two practical implications:

  1. Credential helpers which store a credential for later
     access are likely to use the "path" portion as part of
     the storage key. That means that a request to

       https://example.com/foo.git

     would not use the same credential that was stored in an
     earlier request for:

       https://example.com/bar.git

  2. The prompt shown to the user includes all relevant
     context, including the path.

In most cases, however, users will have a single password
per host. The behavior in (1) will be inconvenient, and the
prompt in (2) will be overly long.

This patch introduces a config option to toggle the
relevance of http paths. When turned on, we use the path as
before. When turned off, we drop the path component from the
context: helpers don't see it, and it does not appear in the
prompt.

This is nothing you couldn't do with a clever credential
helper at the start of your stack, like:

  [credential "http://"]
	helper = "!f() { grep -v ^path= ; }; f"
	helper = your_real_helper

But doing this:

  [credential]
	useHttpPath = false

is way easier and more readable. Furthermore, since most
users will want the "off" behavior, that is the new default.
Users who want it "on" can set the variable (either for all
credentials, or just for a subset using
credential.*.useHttpPath).

Signed-off-by: Jeff King <peff@peff.net>
---
 credential.c           |   14 ++++++++++++++
 credential.h           |    3 ++-
 t/t0300-credentials.sh |   29 +++++++++++++++++++++++++++++
 t/t5550-http-fetch.sh  |    2 +-
 4 files changed, 46 insertions(+), 2 deletions(-)

diff --git a/credential.c b/credential.c
index 3c17ea1..a17eafe 100644
--- a/credential.c
+++ b/credential.c
@@ -69,16 +69,30 @@ static int credential_config_callback(const char *var, const char *value,
 		if (!c->username)
 			c->username = xstrdup(value);
 	}
+	else if (!strcmp(key, "usehttppath"))
+		c->use_http_path = git_config_bool(var, value);
 
 	return 0;
 }
 
+static int proto_is_http(const char *s)
+{
+	if (!s)
+		return 0;
+	return !strcmp(s, "https") || !strcmp(s, "http");
+}
+
 static void credential_apply_config(struct credential *c)
 {
 	if (c->configured)
 		return;
 	git_config(credential_config_callback, c);
 	c->configured = 1;
+
+	if (!c->use_http_path && proto_is_http(c->protocol)) {
+		free(c->path);
+		c->path = NULL;
+	}
 }
 
 static void credential_describe(struct credential *c, struct strbuf *out)
diff --git a/credential.h b/credential.h
index e504272..96ea41b 100644
--- a/credential.h
+++ b/credential.h
@@ -6,7 +6,8 @@
 struct credential {
 	struct string_list helpers;
 	unsigned approved:1,
-		 configured:1;
+		 configured:1,
+		 use_http_path:1;
 
 	char *username;
 	char *password;
diff --git a/t/t0300-credentials.sh b/t/t0300-credentials.sh
index 53e94bc..885af8f 100755
--- a/t/t0300-credentials.sh
+++ b/t/t0300-credentials.sh
@@ -247,4 +247,33 @@ test_expect_success 'pull username from config' '
 	EOF
 '
 
+test_expect_success 'http paths can be part of context' '
+	check fill "verbatim foo bar" <<-\EOF &&
+	protocol=https
+	host=example.com
+	path=foo.git
+	--
+	username=foo
+	password=bar
+	--
+	verbatim: get
+	verbatim: protocol=https
+	verbatim: host=example.com
+	EOF
+	test_config credential.https://example.com.useHttpPath true &&
+	check fill "verbatim foo bar" <<-\EOF
+	protocol=https
+	host=example.com
+	path=foo.git
+	--
+	username=foo
+	password=bar
+	--
+	verbatim: get
+	verbatim: protocol=https
+	verbatim: host=example.com
+	verbatim: path=foo.git
+	EOF
+'
+
 test_done
diff --git a/t/t5550-http-fetch.sh b/t/t5550-http-fetch.sh
index 3262f90..95a133d 100755
--- a/t/t5550-http-fetch.sh
+++ b/t/t5550-http-fetch.sh
@@ -53,7 +53,7 @@ test_expect_success 'setup askpass helpers' '
 '
 
 expect_askpass() {
-	dest=$HTTPD_DEST/auth/repo.git
+	dest=$HTTPD_DEST
 	{
 		case "$1" in
 		none)
-- 
1.7.8.rc2.40.gaf387

Re: [PATCHv3 08/13] credential: make relevance of http path configurable

[Jakub Narebski]

Jeff King <peff@peff.net> writes:

[...]
> This is nothing you couldn't do with a clever credential
> helper at the start of your stack, like:
> 
>   [credential "http://"]
> 	helper = "!f() { grep -v ^path= ; }; f"
> 	helper = your_real_helper
> 
> But doing this:
> 
>   [credential]
> 	useHttpPath = false

Shouldn't this be 'usePath' or 'usePathComponent' or 'useRepositoryPath',
etc.?  Because if^W when remote helper for Subversion is complete, you
could have svn://svnserve.example.com/path/to/repo as an URL... which
would be not HTTP(S). 

-- 
Jakub Narębski

Re: [PATCHv3 08/13] credential: make relevance of http path configurable

[Jeff King]

On Sat, Dec 10, 2011 at 03:50:11AM -0800, Jakub Narebski wrote:

> > This is nothing you couldn't do with a clever credential
> > helper at the start of your stack, like:
> > 
> >   [credential "http://"]
> > 	helper = "!f() { grep -v ^path= ; }; f"
> > 	helper = your_real_helper
> > 
> > But doing this:
> > 
> >   [credential]
> > 	useHttpPath = false
> 
> Shouldn't this be 'usePath' or 'usePathComponent' or 'useRepositoryPath',
> etc.?  Because if^W when remote helper for Subversion is complete, you
> could have svn://svnserve.example.com/path/to/repo as an URL... which
> would be not HTTP(S).

It must be per-protocol, because paths will be relevant for some
protocols (e.g., unlocking certificates in the local filesystem).
So if anything, it would be "useNetworkPath" or something, if we wanted
to unify svn and http. But it would also be OK to have a separate flag
for http and svn, which is more flexible (and most users aren't going to
set it at all, so they won't notice).

-Peff

[PATCHv3 09/13] docs: end-user documentation for the credential subsystem

[Jeff King]

The credential API and helper format is already defined in
technical/api-credentials.txt.  This presents the end-user
view.

Signed-off-by: Jeff King <peff@peff.net>
---
 Documentation/Makefile           |    1 +
 Documentation/config.txt         |   23 +++++
 Documentation/gitcredentials.txt |  171 ++++++++++++++++++++++++++++++++++++++
 3 files changed, 195 insertions(+), 0 deletions(-)
 create mode 100644 Documentation/gitcredentials.txt

diff --git a/Documentation/Makefile b/Documentation/Makefile
index 304b31e..116f175 100644
--- a/Documentation/Makefile
+++ b/Documentation/Makefile
@@ -7,6 +7,7 @@ MAN5_TXT=gitattributes.txt gitignore.txt gitmodules.txt githooks.txt \
 MAN7_TXT=gitcli.txt gittutorial.txt gittutorial-2.txt \
 	gitcvs-migration.txt gitcore-tutorial.txt gitglossary.txt \
 	gitdiffcore.txt gitnamespaces.txt gitrevisions.txt gitworkflows.txt
+MAN7_TXT += gitcredentials.txt
 
 MAN_TXT = $(MAN1_TXT) $(MAN5_TXT) $(MAN7_TXT)
 MAN_XML=$(patsubst %.txt,%.xml,$(MAN_TXT))
diff --git a/Documentation/config.txt b/Documentation/config.txt
index 8a7d2d4..c6630c7 100644
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -834,6 +834,29 @@ commit.template::
 	"{tilde}/" is expanded to the value of `$HOME` and "{tilde}user/" to the
 	specified user's home directory.
 
+credential.helper::
+	Specify an external helper to be called when a username or
+	password credential is needed; the helper may consult external
+	storage to avoid prompting the user for the credentials. See
+	linkgit:gitcredentials[7] for details.
+
+credential.useHttpPath::
+	When acquiring credentials, consider the "path" component of an http
+	or https URL to be important. Defaults to false. See
+	linkgit:gitcredentials[7] for more information.
+
+credential.username::
+	If no username is set for a network authentication, use this username
+	by default. See credential.<context>.* below, and
+	linkgit:gitcredentials[7].
+
+credential.<url>.*::
+	Any of the credential.* options above can be applied selectively to
+	some credentials. For example "credential.https://example.com.username"
+	would set the default username only for https connections to
+	example.com. See linkgit:gitcredentials[7] for details on how URLs are
+	matched.
+
 include::diff-config.txt[]
 
 difftool.<tool>.path::
diff --git a/Documentation/gitcredentials.txt b/Documentation/gitcredentials.txt
new file mode 100644
index 0000000..07f6596
--- /dev/null
+++ b/Documentation/gitcredentials.txt
@@ -0,0 +1,171 @@
+gitcredentials(7)
+=================
+
+NAME
+----
+gitcredentials - providing usernames and passwords to git
+
+SYNOPSIS
+--------
+------------------
+git config credential.https://example.com.username myusername
+git config credential.helper "$helper $options"
+------------------
+
+DESCRIPTION
+-----------
+
+Git will sometimes need credentials from the user in order to perform
+operations; for example, it may need to ask for a username and password
+in order to access a remote repository over HTTP. This manual describes
+the mechanisms git uses to request these credentials, as well as some
+features to avoid inputting these credentials repeatedly.
+
+REQUESTING CREDENTIALS
+----------------------
+
+Without any credential helpers defined, git will try the following
+strategies to ask the user for usernames and passwords:
+
+1. If the `GIT_ASKPASS` environment variable is set, the program
+   specified by the variable is invoked. A suitable prompt is provided
+   to the program on the command line, and the user's input is read
+   from its standard output.
+
+2. Otherwise, if the `core.askpass` configuration variable is set, its
+   value is used as above.
+
+3. Otherwise, if the `SSH_ASKPASS` environment variable is set, its
+   value is used as above.
+
+4. Otherwise, the user is prompted on the terminal.
+
+AVOIDING REPETITION
+-------------------
+
+It can be cumbersome to input the same credentials over and over.  Git
+provides two methods to reduce this annoyance:
+
+1. Static configuration of usernames for a given authentication context.
+
+2. Credential helpers to cache or store passwords, or to interact with
+   a system password wallet or keychain.
+
+The first is simple and appropriate if you do not have secure storage available
+for a password. It is generally configured by adding this to your config:
+
+---------------------------------------
+[credential "https://example.com"]
+	username = me
+---------------------------------------
+
+Credential helpers, on the other hand, are external programs from which git can
+request both usernames and passwords; they typically interface with secure
+storage provided by the OS or other programs.
+
+To use a helper, you must first select one to use.  Git does not yet
+include any credential helpers, but you may have third-party helpers
+installed; search for `credential-*` in the output of `git help -a`, and
+consult the documentation of individual helpers.  Once you have selected
+a helper, you can tell git to use it by putting its name into the
+credential.helper variable.
+
+1. Find a helper.
++
+-------------------------------------------
+$ git help -a | grep credential-
+credential-foo
+-------------------------------------------
+
+2. Read its description.
++
+-------------------------------------------
+$ git help credential-foo
+-------------------------------------------
+
+3. Tell git to use it.
++
+-------------------------------------------
+$ git config --global credential.helper foo
+-------------------------------------------
+
+If there are multiple instances of the `credential.helper` configuration
+variable, each helper will be tried in turn, and may provide a username,
+password, or nothing. Once git has acquired both a username and a
+password, no more helpers will be tried.
+
+
+CREDENTIAL CONTEXTS
+-------------------
+
+Git considers each credential to have a context defined by a URL. This context
+is used to look up context-specific configuration, and is passed to any
+helpers, which may use it as an index into secure storage.
+
+For instance, imagine we are accessing `https://example.com/foo.git`. When git
+looks into a config file to see if a section matches this context, it will
+consider the two a match if the context is a more-specific subset of the
+pattern in the config file. For example, if you have this in your config file:
+
+--------------------------------------
+[credential "https://example.com"]
+	username = foo
+--------------------------------------
+
+then we will match: both protocols are the same, both hosts are the same, and
+the "pattern" URL does not care about the path component at all. However, this
+context would not match:
+
+--------------------------------------
+[credential "https://kernel.org"]
+	username = foo
+--------------------------------------
+
+because the hostnames differ. Nor would it match `foo.example.com`; git
+compares hostnames exactly, without considering whether two hosts are part of
+the same domain. Likewise, a config entry for `http://example.com` would not
+match: git compares the protocols exactly.
+
+
+CONFIGURATION OPTIONS
+---------------------
+
+Options for a credential context can be configured either in
+`credential.\*` (which applies to all credentials), or
+`credential.<url>.\*`, where <url> matches the context as described
+above.
+
+The following options are available in either location:
+
+helper::
+
+	The name of an external credential helper, and any associated options.
+	If the helper name is not an absolute path, then the string `git
+	credential-` is prepended. The resulting string is executed by the
+	shell (so, for example, setting this to `foo --option=bar` will execute
+	`git credential-foo --option=bar` via the shell. See the manual of
+	specific helpers for examples of their use.
+
+username::
+
+	A default username, if one is not provided in the URL.
+
+useHttpPath::
+
+	By default, git does not consider the "path" component of an http URL
+	to be worth matching via external helpers. This means that a credential
+	stored for `https://example.com/foo.git` will also be used for
+	`https://example.com/bar.git`. If you do want to distinguish these
+	cases, set this option to `true`.
+
+
+CUSTOM HELPERS
+--------------
+
+You can write your own custom helpers to interface with any system in
+which you keep credentials. See the documentation for git's
+link:technical/api-credentials.html[credentials API] for details.
+
+GIT
+---
+Part of the linkgit:git[1] suite
-- 
1.7.8.rc2.40.gaf387

[PATCHv3 10/13] credentials: add "cache" helper

[Jeff King]

If you access repositories over smart-http using http
authentication, then it can be annoying to have git ask you
for your password repeatedly. We cache credentials in
memory, of course, but git is composed of many small
programs. Having to input your password for each one can be
frustrating.

This patch introduces a credential helper that will cache
passwords in memory for a short period of time.

Signed-off-by: Jeff King <peff@peff.net>
---
Since the previous round, the tests have been tweaked to remove the use
of the "ftp" protocol. While this worked just fine for our cache and
store helpers, git doesn't actually generate protocol lines like that,
and some helpers may not understand it (e.g., the OS X helper has to
convert the protocol strings into numeric constants, and doesn't bother
converting things that git doesn't generate). And we use the same
battery of tests for the internal helpers as for external ones.

 .gitignore                                     |    2 +
 Documentation/git-credential-cache--daemon.txt |   26 +++
 Documentation/git-credential-cache.txt         |   77 +++++++
 Documentation/gitcredentials.txt               |   17 +-
 Makefile                                       |    3 +
 credential-cache--daemon.c                     |  269 ++++++++++++++++++++++++
 credential-cache.c                             |  120 +++++++++++
 git-compat-util.h                              |    1 +
 t/lib-credential.sh                            |  221 +++++++++++++++++++
 t/t0301-credential-cache.sh                    |   18 ++
 unix-socket.c                                  |   56 +++++
 unix-socket.h                                  |    7 +
 12 files changed, 812 insertions(+), 5 deletions(-)
 create mode 100644 Documentation/git-credential-cache--daemon.txt
 create mode 100644 Documentation/git-credential-cache.txt
 create mode 100644 credential-cache--daemon.c
 create mode 100644 credential-cache.c
 create mode 100755 t/t0301-credential-cache.sh
 create mode 100644 unix-socket.c
 create mode 100644 unix-socket.h

diff --git a/.gitignore b/.gitignore
index 7d2fefc..a6b0bd4 100644
--- a/.gitignore
+++ b/.gitignore
@@ -30,6 +30,8 @@
 /git-commit-tree
 /git-config
 /git-count-objects
+/git-credential-cache
+/git-credential-cache--daemon
 /git-cvsexportcommit
 /git-cvsimport
 /git-cvsserver
diff --git a/Documentation/git-credential-cache--daemon.txt b/Documentation/git-credential-cache--daemon.txt
new file mode 100644
index 0000000..11edc5a
--- /dev/null
+++ b/Documentation/git-credential-cache--daemon.txt
@@ -0,0 +1,26 @@
+git-credential-cache--daemon(1)
+===============================
+
+NAME
+----
+git-credential-cache--daemon - temporarily store user credentials in memory
+
+SYNOPSIS
+--------
+[verse]
+git credential-cache--daemon <socket>
+
+DESCRIPTION
+-----------
+
+NOTE: You probably don't want to invoke this command yourself; it is
+started automatically when you use linkgit:git-credential-cache[1].
+
+This command listens on the Unix domain socket specified by `<socket>`
+for `git-credential-cache` clients. Clients may store and retrieve
+credentials. Each credential is held for a timeout specified by the
+client; once no credentials are held, the daemon exits.
+
+GIT
+---
+Part of the linkgit:git[1] suite
diff --git a/Documentation/git-credential-cache.txt b/Documentation/git-credential-cache.txt
new file mode 100644
index 0000000..f3d09c5
--- /dev/null
+++ b/Documentation/git-credential-cache.txt
@@ -0,0 +1,77 @@
+git-credential-cache(1)
+=======================
+
+NAME
+----
+git-credential-cache - helper to temporarily store passwords in memory
+
+SYNOPSIS
+--------
+-----------------------------
+git config credential.helper 'cache [options]'
+-----------------------------
+
+DESCRIPTION
+-----------
+
+This command caches credentials in memory for use by future git
+programs. The stored credentials never touch the disk, and are forgotten
+after a configurable timeout.  The cache is accessible over a Unix
+domain socket, restricted to the current user by filesystem permissions.
+
+You probably don't want to invoke this command directly; it is meant to
+be used as a credential helper by other parts of git. See
+linkgit:gitcredentials[7] or `EXAMPLES` below.
+
+OPTIONS
+-------
+
+--timeout <seconds>::
+
+	Number of seconds to cache credentials (default: 900).
+
+--socket <path>::
+
+	Use `<path>` to contact a running cache daemon (or start a new
+	cache daemon if one is not started). Defaults to
+	`~/.git-credential-cache/socket`. If your home directory is on a
+	network-mounted filesystem, you may need to change this to a
+	local filesystem.
+
+CONTROLLING THE DAEMON
+----------------------
+
+If you would like the daemon to exit early, forgetting all cached
+credentials before their timeout, you can issue an `exit` action:
+
+--------------------------------------
+git credential-cache exit
+--------------------------------------
+
+EXAMPLES
+--------
+
+The point of this helper is to reduce the number of times you must type
+your username or password. For example:
+
+------------------------------------
+$ git config credential.helper cache
+$ git push http://example.com/repo.git
+Username: <type your username>
+Password: <type your password>
+
+[work for 5 more minutes]
+$ git push http://example.com/repo.git
+[your credentials are used automatically]
+------------------------------------
+
+You can provide options via the credential.helper configuration
+variable (this example drops the cache time to 5 minutes):
+
+-------------------------------------------------------
+$ git config credential.helper 'cache --timeout=300'
+-------------------------------------------------------
+
+GIT
+---
+Part of the linkgit:git[1] suite
diff --git a/Documentation/gitcredentials.txt b/Documentation/gitcredentials.txt
index 07f6596..4e3f860 100644
--- a/Documentation/gitcredentials.txt
+++ b/Documentation/gitcredentials.txt
@@ -63,11 +63,18 @@ Credential helpers, on the other hand, are external programs from which git can
 request both usernames and passwords; they typically interface with secure
 storage provided by the OS or other programs.
 
-To use a helper, you must first select one to use.  Git does not yet
-include any credential helpers, but you may have third-party helpers
-installed; search for `credential-*` in the output of `git help -a`, and
-consult the documentation of individual helpers.  Once you have selected
-a helper, you can tell git to use it by putting its name into the
+To use a helper, you must first select one to use. Git currently
+includes the following helpers:
+
+cache::
+
+	Cache credentials in memory for a short period of time. See
+	linkgit:git-credential-cache[1] for details.
+
+You may also have third-party helpers installed; search for
+`credential-*` in the output of `git help -a`, and consult the
+documentation of individual helpers.  Once you have selected a helper,
+you can tell git to use it by putting its name into the
 credential.helper variable.
 
 1. Find a helper.
diff --git a/Makefile b/Makefile
index d69f1dd..7ad2fe3 100644
--- a/Makefile
+++ b/Makefile
@@ -427,6 +427,8 @@ PROGRAM_OBJS += show-index.o
 PROGRAM_OBJS += upload-pack.o
 PROGRAM_OBJS += http-backend.o
 PROGRAM_OBJS += sh-i18n--envsubst.o
+PROGRAM_OBJS += credential-cache.o
+PROGRAM_OBJS += credential-cache--daemon.o
 
 PROGRAMS += $(patsubst %.o,git-%$X,$(PROGRAM_OBJS))
 
@@ -702,6 +704,7 @@ LIB_OBJS += transport-helper.o
 LIB_OBJS += tree-diff.o
 LIB_OBJS += tree.o
 LIB_OBJS += tree-walk.o
+LIB_OBJS += unix-socket.o
 LIB_OBJS += unpack-trees.o
 LIB_OBJS += url.o
 LIB_OBJS += usage.o
diff --git a/credential-cache--daemon.c b/credential-cache--daemon.c
new file mode 100644
index 0000000..390f194
--- /dev/null
+++ b/credential-cache--daemon.c
@@ -0,0 +1,269 @@
+#include "cache.h"
+#include "credential.h"
+#include "unix-socket.h"
+#include "sigchain.h"
+
+static const char *socket_path;
+
+static void cleanup_socket(void)
+{
+	if (socket_path)
+		unlink(socket_path);
+}
+
+static void cleanup_socket_on_signal(int sig)
+{
+	cleanup_socket();
+	sigchain_pop(sig);
+	raise(sig);
+}
+
+struct credential_cache_entry {
+	struct credential item;
+	unsigned long expiration;
+};
+static struct credential_cache_entry *entries;
+static int entries_nr;
+static int entries_alloc;
+
+static void cache_credential(struct credential *c, int timeout)
+{
+	struct credential_cache_entry *e;
+
+	ALLOC_GROW(entries, entries_nr + 1, entries_alloc);
+	e = &entries[entries_nr++];
+
+	/* take ownership of pointers */
+	memcpy(&e->item, c, sizeof(*c));
+	memset(c, 0, sizeof(*c));
+	e->expiration = time(NULL) + timeout;
+}
+
+static struct credential_cache_entry *lookup_credential(const struct credential *c)
+{
+	int i;
+	for (i = 0; i < entries_nr; i++) {
+		struct credential *e = &entries[i].item;
+		if (credential_match(c, e))
+			return &entries[i];
+	}
+	return NULL;
+}
+
+static void remove_credential(const struct credential *c)
+{
+	struct credential_cache_entry *e;
+
+	e = lookup_credential(c);
+	if (e)
+		e->expiration = 0;
+}
+
+static int check_expirations(void)
+{
+	static unsigned long wait_for_entry_until;
+	int i = 0;
+	unsigned long now = time(NULL);
+	unsigned long next = (unsigned long)-1;
+
+	/*
+	 * Initially give the client 30 seconds to actually contact us
+	 * and store a credential before we decide there's no point in
+	 * keeping the daemon around.
+	 */
+	if (!wait_for_entry_until)
+		wait_for_entry_until = now + 30;
+
+	while (i < entries_nr) {
+		if (entries[i].expiration <= now) {
+			entries_nr--;
+			credential_clear(&entries[i].item);
+			if (i != entries_nr)
+				memcpy(&entries[i], &entries[entries_nr], sizeof(*entries));
+			/*
+			 * Stick around 30 seconds in case a new credential
+			 * shows up (e.g., because we just removed a failed
+			 * one, and we will soon get the correct one).
+			 */
+			wait_for_entry_until = now + 30;
+		}
+		else {
+			if (entries[i].expiration < next)
+				next = entries[i].expiration;
+			i++;
+		}
+	}
+
+	if (!entries_nr) {
+		if (wait_for_entry_until <= now)
+			return 0;
+		next = wait_for_entry_until;
+	}
+
+	return next - now;
+}
+
+static int read_request(FILE *fh, struct credential *c,
+			struct strbuf *action, int *timeout) {
+	static struct strbuf item = STRBUF_INIT;
+	const char *p;
+
+	strbuf_getline(&item, fh, '\n');
+	p = skip_prefix(item.buf, "action=");
+	if (!p)
+		return error("client sent bogus action line: %s", item.buf);
+	strbuf_addstr(action, p);
+
+	strbuf_getline(&item, fh, '\n');
+	p = skip_prefix(item.buf, "timeout=");
+	if (!p)
+		return error("client sent bogus timeout line: %s", item.buf);
+	*timeout = atoi(p);
+
+	if (credential_read(c, fh) < 0)
+		return -1;
+	return 0;
+}
+
+static void serve_one_client(FILE *in, FILE *out)
+{
+	struct credential c = CREDENTIAL_INIT;
+	struct strbuf action = STRBUF_INIT;
+	int timeout = -1;
+
+	if (read_request(in, &c, &action, &timeout) < 0)
+		/* ignore error */ ;
+	else if (!strcmp(action.buf, "get")) {
+		struct credential_cache_entry *e = lookup_credential(&c);
+		if (e) {
+			fprintf(out, "username=%s\n", e->item.username);
+			fprintf(out, "password=%s\n", e->item.password);
+		}
+	}
+	else if (!strcmp(action.buf, "exit"))
+		exit(0);
+	else if (!strcmp(action.buf, "erase"))
+		remove_credential(&c);
+	else if (!strcmp(action.buf, "store")) {
+		if (timeout < 0)
+			warning("cache client didn't specify a timeout");
+		else if (!c.username || !c.password)
+			warning("cache client gave us a partial credential");
+		else {
+			remove_credential(&c);
+			cache_credential(&c, timeout);
+		}
+	}
+	else
+		warning("cache client sent unknown action: %s", action.buf);
+
+	credential_clear(&c);
+	strbuf_release(&action);
+}
+
+static int serve_cache_loop(int fd)
+{
+	struct pollfd pfd;
+	unsigned long wakeup;
+
+	wakeup = check_expirations();
+	if (!wakeup)
+		return 0;
+
+	pfd.fd = fd;
+	pfd.events = POLLIN;
+	if (poll(&pfd, 1, 1000 * wakeup) < 0) {
+		if (errno != EINTR)
+			die_errno("poll failed");
+		return 1;
+	}
+
+	if (pfd.revents & POLLIN) {
+		int client, client2;
+		FILE *in, *out;
+
+		client = accept(fd, NULL, NULL);
+		if (client < 0) {
+			warning("accept failed: %s", strerror(errno));
+			return 1;
+		}
+		client2 = dup(client);
+		if (client2 < 0) {
+			warning("dup failed: %s", strerror(errno));
+			close(client);
+			return 1;
+		}
+
+		in = xfdopen(client, "r");
+		out = xfdopen(client2, "w");
+		serve_one_client(in, out);
+		fclose(in);
+		fclose(out);
+	}
+	return 1;
+}
+
+static void serve_cache(const char *socket_path)
+{
+	int fd;
+
+	fd = unix_stream_listen(socket_path);
+	if (fd < 0)
+		die_errno("unable to bind to '%s'", socket_path);
+
+	printf("ok\n");
+	fclose(stdout);
+
+	while (serve_cache_loop(fd))
+		; /* nothing */
+
+	close(fd);
+	unlink(socket_path);
+}
+
+static const char permissions_advice[] =
+"The permissions on your socket directory are too loose; other\n"
+"users may be able to read your cached credentials. Consider running:\n"
+"\n"
+"	chmod 0700 %s";
+static void check_socket_directory(const char *path)
+{
+	struct stat st;
+	char *path_copy = xstrdup(path);
+	char *dir = dirname(path_copy);
+
+	if (!stat(dir, &st)) {
+		if (st.st_mode & 077)
+			die(permissions_advice, dir);
+		free(path_copy);
+		return;
+	}
+
+	/*
+	 * We must be sure to create the directory with the correct mode,
+	 * not just chmod it after the fact; otherwise, there is a race
+	 * condition in which somebody can chdir to it, sleep, then try to open
+	 * our protected socket.
+	 */
+	if (safe_create_leading_directories_const(dir) < 0)
+		die_errno("unable to create directories for '%s'", dir);
+	if (mkdir(dir, 0700) < 0)
+		die_errno("unable to mkdir '%s'", dir);
+	free(path_copy);
+}
+
+int main(int argc, const char **argv)
+{
+	socket_path = argv[1];
+
+	if (!socket_path)
+		die("usage: git-credential-cache--daemon <socket_path>");
+	check_socket_directory(socket_path);
+
+	atexit(cleanup_socket);
+	sigchain_push_common(cleanup_socket_on_signal);
+
+	serve_cache(socket_path);
+
+	return 0;
+}
diff --git a/credential-cache.c b/credential-cache.c
new file mode 100644
index 0000000..dc98372
--- /dev/null
+++ b/credential-cache.c
@@ -0,0 +1,120 @@
+#include "cache.h"
+#include "credential.h"
+#include "string-list.h"
+#include "parse-options.h"
+#include "unix-socket.h"
+#include "run-command.h"
+
+#define FLAG_SPAWN 0x1
+#define FLAG_RELAY 0x2
+
+static int send_request(const char *socket, const struct strbuf *out)
+{
+	int got_data = 0;
+	int fd = unix_stream_connect(socket);
+
+	if (fd < 0)
+		return -1;
+
+	if (write_in_full(fd, out->buf, out->len) < 0)
+		die_errno("unable to write to cache daemon");
+	shutdown(fd, SHUT_WR);
+
+	while (1) {
+		char in[1024];
+		int r;
+
+		r = read_in_full(fd, in, sizeof(in));
+		if (r == 0)
+			break;
+		if (r < 0)
+			die_errno("read error from cache daemon");
+		write_or_die(1, in, r);
+		got_data = 1;
+	}
+	return got_data;
+}
+
+static void spawn_daemon(const char *socket)
+{
+	struct child_process daemon;
+	const char *argv[] = { NULL, NULL, NULL };
+	char buf[128];
+	int r;
+
+	memset(&daemon, 0, sizeof(daemon));
+	argv[0] = "git-credential-cache--daemon";
+	argv[1] = socket;
+	daemon.argv = argv;
+	daemon.no_stdin = 1;
+	daemon.out = -1;
+
+	if (start_command(&daemon))
+		die_errno("unable to start cache daemon");
+	r = read_in_full(daemon.out, buf, sizeof(buf));
+	if (r < 0)
+		die_errno("unable to read result code from cache daemon");
+	if (r != 3 || memcmp(buf, "ok\n", 3))
+		die("cache daemon did not start: %.*s", r, buf);
+	close(daemon.out);
+}
+
+static void do_cache(const char *socket, const char *action, int timeout,
+		     int flags)
+{
+	struct strbuf buf = STRBUF_INIT;
+
+	strbuf_addf(&buf, "action=%s\n", action);
+	strbuf_addf(&buf, "timeout=%d\n", timeout);
+	if (flags & FLAG_RELAY) {
+		if (strbuf_read(&buf, 0, 0) < 0)
+			die_errno("unable to relay credential");
+	}
+
+	if (!send_request(socket, &buf))
+		return;
+	if (flags & FLAG_SPAWN) {
+		spawn_daemon(socket);
+		send_request(socket, &buf);
+	}
+	strbuf_release(&buf);
+}
+
+int main(int argc, const char **argv)
+{
+	char *socket_path = NULL;
+	int timeout = 900;
+	const char *op;
+	const char * const usage[] = {
+		"git credential-cache [options] <action>",
+		NULL
+	};
+	struct option options[] = {
+		OPT_INTEGER(0, "timeout", &timeout,
+			    "number of seconds to cache credentials"),
+		OPT_STRING(0, "socket", &socket_path, "path",
+			   "path of cache-daemon socket"),
+		OPT_END()
+	};
+
+	argc = parse_options(argc, argv, NULL, options, usage, 0);
+	if (!argc)
+		usage_with_options(usage, options);
+	op = argv[0];
+
+	if (!socket_path)
+		socket_path = expand_user_path("~/.git-credential-cache/socket");
+	if (!socket_path)
+		die("unable to find a suitable socket path; use --socket");
+
+	if (!strcmp(op, "exit"))
+		do_cache(socket_path, op, timeout, 0);
+	else if (!strcmp(op, "get") || !strcmp(op, "erase"))
+		do_cache(socket_path, op, timeout, FLAG_RELAY);
+	else if (!strcmp(op, "store"))
+		do_cache(socket_path, op, timeout, FLAG_RELAY|FLAG_SPAWN);
+	else
+		; /* ignore unknown operation */
+
+	return 0;
+}
diff --git a/git-compat-util.h b/git-compat-util.h
index 77062ed..8f3972c 100644
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -135,6 +135,7 @@
 #include <arpa/inet.h>
 #include <netdb.h>
 #include <pwd.h>
+#include <sys/un.h>
 #ifndef NO_INTTYPES_H
 #include <inttypes.h>
 #else
diff --git a/t/lib-credential.sh b/t/lib-credential.sh
index 54ae1f4..4a37cd7 100755
--- a/t/lib-credential.sh
+++ b/t/lib-credential.sh
@@ -21,6 +21,227 @@ read_chunk() {
 	done
 }
 
+# Clear any residual data from previous tests. We only
+# need this when testing third-party helpers which read and
+# write outside of our trash-directory sandbox.
+#
+# Don't bother checking for success here, as it is
+# outside the scope of tests and represents a best effort to
+# clean up after ourselves.
+helper_test_clean() {
+	reject $1 https example.com store-user
+	reject $1 https example.com user1
+	reject $1 https example.com user2
+	reject $1 http path.tld user
+	reject $1 https timeout.tld user
+}
+
+reject() {
+	(
+		echo protocol=$2
+		echo host=$3
+		echo username=$4
+	) | test-credential reject $1
+}
+
+helper_test() {
+	HELPER=$1
+
+	test_expect_success "helper ($HELPER) has no existing data" '
+		check fill $HELPER <<-\EOF
+		protocol=https
+		host=example.com
+		--
+		username=askpass-username
+		password=askpass-password
+		--
+		askpass: Username for '\''https://example.com'\'':
+		askpass: Password for '\''https://askpass-username@example.com'\'':
+		EOF
+	'
+
+	test_expect_success "helper ($HELPER) stores password" '
+		check approve $HELPER <<-\EOF
+		protocol=https
+		host=example.com
+		username=store-user
+		password=store-pass
+		EOF
+	'
+
+	test_expect_success "helper ($HELPER) can retrieve password" '
+		check fill $HELPER <<-\EOF
+		protocol=https
+		host=example.com
+		--
+		username=store-user
+		password=store-pass
+		--
+		EOF
+	'
+
+	test_expect_success "helper ($HELPER) requires matching protocol" '
+		check fill $HELPER <<-\EOF
+		protocol=http
+		host=example.com
+		--
+		username=askpass-username
+		password=askpass-password
+		--
+		askpass: Username for '\''http://example.com'\'':
+		askpass: Password for '\''http://askpass-username@example.com'\'':
+		EOF
+	'
+
+	test_expect_success "helper ($HELPER) requires matching host" '
+		check fill $HELPER <<-\EOF
+		protocol=https
+		host=other.tld
+		--
+		username=askpass-username
+		password=askpass-password
+		--
+		askpass: Username for '\''https://other.tld'\'':
+		askpass: Password for '\''https://askpass-username@other.tld'\'':
+		EOF
+	'
+
+	test_expect_success "helper ($HELPER) requires matching username" '
+		check fill $HELPER <<-\EOF
+		protocol=https
+		host=example.com
+		username=other
+		--
+		username=other
+		password=askpass-password
+		--
+		askpass: Password for '\''https://other@example.com'\'':
+		EOF
+	'
+
+	test_expect_success "helper ($HELPER) requires matching path" '
+		test_config credential.usehttppath true &&
+		check approve $HELPER <<-\EOF &&
+		protocol=http
+		host=path.tld
+		path=foo.git
+		username=user
+		password=pass
+		EOF
+		check fill $HELPER <<-\EOF
+		protocol=http
+		host=path.tld
+		path=bar.git
+		--
+		username=askpass-username
+		password=askpass-password
+		--
+		askpass: Username for '\''http://path.tld/bar.git'\'':
+		askpass: Password for '\''http://askpass-username@path.tld/bar.git'\'':
+		EOF
+	'
+
+	test_expect_success "helper ($HELPER) can forget host" '
+		check reject $HELPER <<-\EOF &&
+		protocol=https
+		host=example.com
+		EOF
+		check fill $HELPER <<-\EOF
+		protocol=https
+		host=example.com
+		--
+		username=askpass-username
+		password=askpass-password
+		--
+		askpass: Username for '\''https://example.com'\'':
+		askpass: Password for '\''https://askpass-username@example.com'\'':
+		EOF
+	'
+
+	test_expect_success "helper ($HELPER) can store multiple users" '
+		check approve $HELPER <<-\EOF &&
+		protocol=https
+		host=example.com
+		username=user1
+		password=pass1
+		EOF
+		check approve $HELPER <<-\EOF &&
+		protocol=https
+		host=example.com
+		username=user2
+		password=pass2
+		EOF
+		check fill $HELPER <<-\EOF &&
+		protocol=https
+		host=example.com
+		username=user1
+		--
+		username=user1
+		password=pass1
+		EOF
+		check fill $HELPER <<-\EOF
+		protocol=https
+		host=example.com
+		username=user2
+		--
+		username=user2
+		password=pass2
+		EOF
+	'
+
+	test_expect_success "helper ($HELPER) can forget user" '
+		check reject $HELPER <<-\EOF &&
+		protocol=https
+		host=example.com
+		username=user1
+		EOF
+		check fill $HELPER <<-\EOF
+		protocol=https
+		host=example.com
+		username=user1
+		--
+		username=user1
+		password=askpass-password
+		--
+		askpass: Password for '\''https://user1@example.com'\'':
+		EOF
+	'
+
+	test_expect_success "helper ($HELPER) remembers other user" '
+		check fill $HELPER <<-\EOF
+		protocol=https
+		host=example.com
+		username=user2
+		--
+		username=user2
+		password=pass2
+		EOF
+	'
+}
+
+helper_test_timeout() {
+	HELPER="$*"
+
+	test_expect_success "helper ($HELPER) times out" '
+		check approve "$HELPER" <<-\EOF &&
+		protocol=https
+		host=timeout.tld
+		username=user
+		password=pass
+		EOF
+		sleep 2 &&
+		check fill "$HELPER" <<-\EOF
+		protocol=https
+		host=timeout.tld
+		--
+		username=askpass-username
+		password=askpass-password
+		--
+		askpass: Username for '\''https://timeout.tld'\'':
+		askpass: Password for '\''https://askpass-username@timeout.tld'\'':
+		EOF
+	'
+}
 
 cat >askpass <<\EOF
 #!/bin/sh
diff --git a/t/t0301-credential-cache.sh b/t/t0301-credential-cache.sh
new file mode 100755
index 0000000..3a65f99
--- /dev/null
+++ b/t/t0301-credential-cache.sh
@@ -0,0 +1,18 @@
+#!/bin/sh
+
+test_description='credential-cache tests'
+. ./test-lib.sh
+. "$TEST_DIRECTORY"/lib-credential.sh
+
+# don't leave a stale daemon running
+trap 'code=$?; git credential-cache exit; (exit $code); die' EXIT
+
+helper_test cache
+helper_test_timeout cache --timeout=1
+
+# we can't rely on our "trap" above working after test_done,
+# as test_done will delete the trash directory containing
+# our socket, leaving us with no way to access the daemon.
+git credential-cache exit
+
+test_done
diff --git a/unix-socket.c b/unix-socket.c
new file mode 100644
index 0000000..84b1509
--- /dev/null
+++ b/unix-socket.c
@@ -0,0 +1,56 @@
+#include "cache.h"
+#include "unix-socket.h"
+
+static int unix_stream_socket(void)
+{
+	int fd = socket(AF_UNIX, SOCK_STREAM, 0);
+	if (fd < 0)
+		die_errno("unable to create socket");
+	return fd;
+}
+
+static void unix_sockaddr_init(struct sockaddr_un *sa, const char *path)
+{
+	int size = strlen(path) + 1;
+	if (size > sizeof(sa->sun_path))
+		die("socket path is too long to fit in sockaddr");
+	memset(sa, 0, sizeof(*sa));
+	sa->sun_family = AF_UNIX;
+	memcpy(sa->sun_path, path, size);
+}
+
+int unix_stream_connect(const char *path)
+{
+	int fd;
+	struct sockaddr_un sa;
+
+	unix_sockaddr_init(&sa, path);
+	fd = unix_stream_socket();
+	if (connect(fd, (struct sockaddr *)&sa, sizeof(sa)) < 0) {
+		close(fd);
+		return -1;
+	}
+	return fd;
+}
+
+int unix_stream_listen(const char *path)
+{
+	int fd;
+	struct sockaddr_un sa;
+
+	unix_sockaddr_init(&sa, path);
+	fd = unix_stream_socket();
+
+	unlink(path);
+	if (bind(fd, (struct sockaddr *)&sa, sizeof(sa)) < 0) {
+		close(fd);
+		return -1;
+	}
+
+	if (listen(fd, 5) < 0) {
+		close(fd);
+		return -1;
+	}
+
+	return fd;
+}
diff --git a/unix-socket.h b/unix-socket.h
new file mode 100644
index 0000000..e271aee
--- /dev/null
+++ b/unix-socket.h
@@ -0,0 +1,7 @@
+#ifndef UNIX_SOCKET_H
+#define UNIX_SOCKET_H
+
+int unix_stream_connect(const char *path);
+int unix_stream_listen(const char *path);
+
+#endif /* UNIX_SOCKET_H */
-- 
1.7.8.rc2.40.gaf387

Re: [PATCHv3 10/13] credentials: add "cache" helper

[Jonathan Nieder]

Hi,

Jeff King wrote:

> This patch introduces a credential helper that will cache
> passwords in memory for a short period of time.
>
> Signed-off-by: Jeff King <peff@peff.net>
[...]
> t/t0301-credential-cache.sh                    |   18 ++

This test is failing for me:

	expecting success: 
			check fill $HELPER <<-\EOF
			protocol=https
			host=example.com
			--
			username=askpass-username
			password=askpass-password
			--
			askpass: Username for 'https://example.com':
			askpass: Password for 'https://askpass-username@example.com':
			EOF

	--- expect-stderr       2012-01-10 00:07:02.398365248 +0000
	+++ stderr      2012-01-10 00:07:02.418364996 +0000
	@@ -1,2 +1,3 @@
	+fatal: socket path is too long to fit in sockaddr
	 askpass: Username for 'https://example.com':
	 askpass: Password for 'https://askpass-username@example.com':
	not ok - 1 helper (cache) has no existing data

I didn't notice until recently because typically the cwd is short.
The sun_path[] array on this machine is 108 bytes; POSIX informs me
that some platforms make it as small as 96 bytes and there's no
guaranteed lower limit.  The machines[*] triggering it were running
tests in a chroot, hence the long path.

So you should be able to reproduce this with

	longpath=foo/bar; # > 6 chars
	longpath=$longpath/$longpath/$longpath/$longpath; # > 24
	longpath=$longpath/$longpath/$longpath/$longpath; # > 96
	longpath=/tmp/$longpath/$longpath
	mkdir -p $longpath
	sh t0301-credential-cache.sh --root=$longpath

Ideas?
---
[*] https://buildd.debian.org/status/logs.php?pkg=git&ver=1%3A1.7.9~rc0-1

 credential-cache.c |   18 +++++++++++++-----
 1 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/credential-cache.c b/credential-cache.c
index dc98372e..fd9304e6 100644
--- a/credential-cache.c
+++ b/credential-cache.c
@@ -82,7 +82,7 @@ static void do_cache(const char *socket, const char *action, int timeout,
 
 int main(int argc, const char **argv)
 {
-	char *socket_path = NULL;
+	const char *socket_path = NULL;
 	int timeout = 900;
 	const char *op;
 	const char * const usage[] = {
@@ -102,10 +102,18 @@ int main(int argc, const char **argv)
 		usage_with_options(usage, options);
 	op = argv[0];
 
-	if (!socket_path)
-		socket_path = expand_user_path("~/.git-credential-cache/socket");
-	if (!socket_path)
-		die("unable to find a suitable socket path; use --socket");
+	if (!socket_path) {
+		char *home = expand_user_path("~");
+		if (!home)
+			die("unable to find a suitable socket path; use --socket");
+
+		if (!chdir(home))
+			socket_path = ".git-credential-cache/socket";
+		else if (errno == ENOENT && !strcmp(op, "exit"))
+			return 0;
+		else
+			die("cannot enter home directory");
+	}
 
 	if (!strcmp(op, "exit"))
 		do_cache(socket_path, op, timeout, 0);
-- 
1.7.8.2

Re: [PATCHv3 10/13] credentials: add "cache" helper

[Jeff King]

On Mon, Jan 09, 2012 at 07:50:38PM -0600, Jonathan Nieder wrote:

> 	--- expect-stderr       2012-01-10 00:07:02.398365248 +0000
> 	+++ stderr      2012-01-10 00:07:02.418364996 +0000
> 	@@ -1,2 +1,3 @@
> 	+fatal: socket path is too long to fit in sockaddr
> 	 askpass: Username for 'https://example.com':
> 	 askpass: Password for 'https://askpass-username@example.com':
> 	not ok - 1 helper (cache) has no existing data
> 
> I didn't notice until recently because typically the cwd is short.
> The sun_path[] array on this machine is 108 bytes; POSIX informs me
> that some platforms make it as small as 96 bytes and there's no
> guaranteed lower limit.  The machines[*] triggering it were running
> tests in a chroot, hence the long path.

Ugh. Some days I really love working on Unix systems. And then some days
you run across junk like this.

Presumably Linux has kept to 108 to avoid breaking older programs.  So
it's not as if we can assume it will be changed soon, or just write this
off as a limitation for old crappy systems.

Googling around, I've seen some indication that you can simply
over-allocate the sockaddr_un and pass a longer length to connect.
However that just seems to yield EINVAL on Linux (and even if it did
work on Linux, I'd be surprised if it worked everywhere).

Which really leaves us with only one option: chdir and bind to a
relative path, as you did below.

> -	if (!socket_path)
> -		socket_path = expand_user_path("~/.git-credential-cache/socket");
> -	if (!socket_path)
> -		die("unable to find a suitable socket path; use --socket");
> +	if (!socket_path) {
> +		char *home = expand_user_path("~");
> +		if (!home)
> +			die("unable to find a suitable socket path; use --socket");
> +
> +		if (!chdir(home))
> +			socket_path = ".git-credential-cache/socket";
> +		else if (errno == ENOENT && !strcmp(op, "exit"))
> +			return 0;
> +		else
> +			die("cannot enter home directory");
> +	}

I think this is the right approach, but the wrong place to do it. Your
patch only helps people using the default path (so passing
--socket=$longpath would still be broken). And we'd need a similar fix
for the binding side in credential-cache--daemon.

Here's a patch which passes your $longpath test.

-- >8 --
Subject: [PATCH] unix-socket: handle long socket pathnames

On many systems, the sockaddr_un.sun_path field is quite
small. Even on Linux, it is only 108 characters. A user of
the credential-cache daemon can easily surpass this,
especially if their home directory is in a deep directory
tree (since the default location expands ~/.git-credentials).

We can hack around this in the unix-socket.[ch] code by
doing a chdir() to the enclosing directory, feeding the
relative basename to the socket functions, and then
restoring the working directory.

This introduces several new possible error cases for
creating a socket, including an irrecoverable one in the
case that we can't restore the working directory. In the
case of the credential-cache code, we could perhaps get away
with simply chdir()-ing to the socket directory and never
coming back. However, I'd rather do it at the lower level
for a few reasons:

  1. It keeps the hackery behind an opaque interface instead
     of polluting the main program logic.

  2. A hack in credential-cache won't help any unix-socket
     users who come along later.

  3. The chdir trickery isn't that likely to fail (basically
     it's only a problem if your cwd is missing or goes away
     while you're running).  And because we only enable the
     hack when we get a too-long name, it can only fail in
     cases that would have failed under the previous code
     anyway.

Signed-off-by: Jeff King <peff@peff.net>
---
 unix-socket.c |   74 +++++++++++++++++++++++++++++++++++++++++++++++++++++----
 1 files changed, 69 insertions(+), 5 deletions(-)

diff --git a/unix-socket.c b/unix-socket.c
index 84b1509..664782a 100644
--- a/unix-socket.c
+++ b/unix-socket.c
@@ -9,27 +9,86 @@ static int unix_stream_socket(void)
 	return fd;
 }
 
-static void unix_sockaddr_init(struct sockaddr_un *sa, const char *path)
+static int chdir_len(const char *orig, int len)
+{
+	char *path = xmemdupz(orig, len);
+	int r = chdir(path);
+	free(path);
+	return r;
+}
+
+struct unix_sockaddr_context {
+	char orig_dir[PATH_MAX];
+};
+
+static void unix_sockaddr_cleanup(struct unix_sockaddr_context *ctx)
+{
+	if (!ctx->orig_dir[0])
+		return;
+	/*
+	 * If we fail, we can't just return an error, since we have
+	 * moved the cwd of the whole process, which could confuse calling
+	 * code.  We are better off to just die.
+	 */
+	if (chdir(ctx->orig_dir) < 0)
+		die("unable to restore original working directory");
+}
+
+static int unix_sockaddr_init(struct sockaddr_un *sa, const char *path,
+			      struct unix_sockaddr_context *ctx)
 {
 	int size = strlen(path) + 1;
-	if (size > sizeof(sa->sun_path))
-		die("socket path is too long to fit in sockaddr");
+
+	ctx->orig_dir[0] = '\0';
+	if (size > sizeof(sa->sun_path)) {
+		const char *slash = find_last_dir_sep(path);
+		const char *dir;
+		int dir_len;
+
+		if (!slash) {
+			errno = ENAMETOOLONG;
+			return -1;
+		}
+
+		dir = path;
+		dir_len = slash - path;
+
+		path = slash + 1;
+		size = strlen(path) + 1;
+		if (size > sizeof(sa->sun_path)) {
+			errno = ENAMETOOLONG;
+			return -1;
+		}
+
+		if (!getcwd(ctx->orig_dir, sizeof(ctx->orig_dir))) {
+			errno = ENAMETOOLONG;
+			return -1;
+		}
+		if (chdir_len(dir, dir_len) < 0)
+			return -1;
+	}
+
 	memset(sa, 0, sizeof(*sa));
 	sa->sun_family = AF_UNIX;
 	memcpy(sa->sun_path, path, size);
+	return 0;
 }
 
 int unix_stream_connect(const char *path)
 {
 	int fd;
 	struct sockaddr_un sa;
+	struct unix_sockaddr_context ctx;
 
-	unix_sockaddr_init(&sa, path);
+	if (unix_sockaddr_init(&sa, path, &ctx) < 0)
+		return -1;
 	fd = unix_stream_socket();
 	if (connect(fd, (struct sockaddr *)&sa, sizeof(sa)) < 0) {
+		unix_sockaddr_cleanup(&ctx);
 		close(fd);
 		return -1;
 	}
+	unix_sockaddr_cleanup(&ctx);
 	return fd;
 }
 
@@ -37,20 +96,25 @@ int unix_stream_listen(const char *path)
 {
 	int fd;
 	struct sockaddr_un sa;
+	struct unix_sockaddr_context ctx;
 
-	unix_sockaddr_init(&sa, path);
+	if (unix_sockaddr_init(&sa, path, &ctx) < 0)
+		return -1;
 	fd = unix_stream_socket();
 
 	unlink(path);
 	if (bind(fd, (struct sockaddr *)&sa, sizeof(sa)) < 0) {
+		unix_sockaddr_cleanup(&ctx);
 		close(fd);
 		return -1;
 	}
 
 	if (listen(fd, 5) < 0) {
+		unix_sockaddr_cleanup(&ctx);
 		close(fd);
 		return -1;
 	}
 
+	unix_sockaddr_cleanup(&ctx);
 	return fd;
 }
-- 
1.7.9.rc0.33.g15ced5

Re: [PATCHv3 10/13] credentials: add "cache" helper

[Jeff King]

On Mon, Jan 09, 2012 at 11:44:30PM -0500, Jeff King wrote:

> Subject: [PATCH] unix-socket: handle long socket pathnames

And I think this should go on top. You were lucky enough that I used a
die() in the original code for your condition (because I thought it was
a "this could never happen, right?" condition). Had it simply returned
an error, the cache-daemon would have silently failed to do anything,
which would have been much more confusing for you. :)

We probably should have done this as part of Clemens' 98c2924, but I
didn't think of it then (but the same reasoning applies to both
patches).

-- >8 --
Subject: [PATCH] credential-cache: report more daemon connection errors

Originally, this code remained relatively silent when we
failed to connect to the cache. The idea was that it was
simply a cache, and we didn't want to bother the user with
temporary failures (the worst case is that we would simply
ask their password again).

However, if you have a configuration failure or other
problem, it is helpful for the daemon to report those
problems. Git will happily ignore the failed error code, but
the extra information to stderr can help the user diagnose
the problem.

Signed-off-by: Jeff King <peff@peff.net>
---
 credential-cache.c |   10 +++++++---
 1 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/credential-cache.c b/credential-cache.c
index b15a9a7..1933018 100644
--- a/credential-cache.c
+++ b/credential-cache.c
@@ -71,10 +71,14 @@ static void do_cache(const char *socket, const char *action, int timeout,
 			die_errno("unable to relay credential");
 	}
 
-	if (send_request(socket, &buf) < 0 && (flags & FLAG_SPAWN)) {
-		spawn_daemon(socket);
-		if (send_request(socket, &buf) < 0)
+	if (send_request(socket, &buf) < 0) {
+		if (errno != ENOENT)
 			die_errno("unable to connect to cache daemon");
+		if (flags & FLAG_SPAWN) {
+			spawn_daemon(socket);
+			if (send_request(socket, &buf) < 0)
+				die_errno("unable to connect to cache daemon");
+		}
 	}
 	strbuf_release(&buf);
 }
-- 
1.7.9.rc0.33.g15ced5

Re: [PATCHv3 10/13] credentials: add "cache" helper

[Junio C Hamano]

Thanks, these look sane.

Will queue both to 'next' aiming for 'master' before 1.7.9-rc1.

Re: [PATCHv3 10/13] credentials: add "cache" helper

[Jeff King]

On Mon, Jan 09, 2012 at 11:57:33PM -0500, Jeff King wrote:

> Subject: [PATCH] credential-cache: report more daemon connection errors
> 
> Originally, this code remained relatively silent when we
> failed to connect to the cache. The idea was that it was
> simply a cache, and we didn't want to bother the user with
> temporary failures (the worst case is that we would simply
> ask their password again).
> 
> However, if you have a configuration failure or other
> problem, it is helpful for the daemon to report those
> problems. Git will happily ignore the failed error code, but
> the extra information to stderr can help the user diagnose
> the problem.

This actually has a minor regression, fixed below.

-- >8 --
Subject: [PATCH] credential-cache: ignore "connection refused" errors

The credential-cache helper will try to connect to its
daemon over a unix socket. Originally, a failure to do so
was silently ignored, and we would either give up (if
performing a "get" or "erase" operation), or spawn a new
daemon (for a "store" operation).

But since 8ec6c8d, we try to report more errors. We detect a
missing daemon by checking for ENOENT on our connection
attempt.  If the daemon is missing, we continue as before
(giving up or spawning a new daemon). For any other error,
we die and report the problem.

However, checking for ENOENT is not sufficient for a missing
daemon. We might also get ECONNREFUSED if a dead daemon
process left a stale socket. This generally shouldn't
happen, as the daemon cleans up after itself, but the daemon
may not always be given a chance to do so (e.g., power loss,
"kill -9").

The resulting state is annoying not just because the helper
outputs an extra useless message, but because it actually
blocks the helper from spawning a new daemon to replace the
stale socket.

Fix it by checking for ECONNREFUSED.

Signed-off-by: Jeff King <peff@peff.net>
---
If we really want to go belt-and-suspenders, the logic should perhaps be
changed to:

  if (send_request(socket, &buf < 0) {
          /* if we're starting a new one, who cares why it didn't work */
          if (flags & FLAG_SPAWN) {
                  spawn_daemon(socket);
                  if (send_request(socket, &buf) < 0)
                          die_errno("unable to connect to spawned daemon");
          }
          /* otherwise, report any non-minor errors */
          else if(errno != ENOENT && errno != ECONNREFUSED)
                  die_errno("unable to connect to cache daemon");
          /* otherwise we are just missing the daemon, and we can ignore */
  }

but that implies there is some condition besides ENOENT and ECONNREFUSED
where actually starting a new daemon (which will try to unlink whatever
is there now!) would be a good idea. I'd rather be conservative and
see if anybody reports a real-world case.

 credential-cache.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/credential-cache.c b/credential-cache.c
index 1933018..9a03792 100644
--- a/credential-cache.c
+++ b/credential-cache.c
@@ -72,7 +72,7 @@ static void do_cache(const char *socket, const char *action, int timeout,
 	}
 
 	if (send_request(socket, &buf) < 0) {
-		if (errno != ENOENT)
+		if (errno != ENOENT && errno != ECONNREFUSED)
 			die_errno("unable to connect to cache daemon");
 		if (flags & FLAG_SPAWN) {
 			spawn_daemon(socket);
-- 
1.7.9.rc0.33.gd3c17

Re: [PATCHv3 10/13] credentials: add "cache" helper

[Junio C Hamano]

Thanks, really appreciated.

Re: [PATCHv3 10/13] credentials: add "cache" helper

[Jonathan Nieder]

Jeff King wrote:

>   2. A hack in credential-cache won't help any unix-socket
>      users who come along later.
>
>   3. The chdir trickery isn't that likely to fail (basically
>      it's only a problem if your cwd is missing or goes away
>      while you're running).  And because we only enable the
>      hack when we get a too-long name, it can only fail in
>      cases that would have failed under the previous code
>      anyway.
>
> Signed-off-by: Jeff King <peff@peff.net>

A part of me worries that this assumption (3), and the additional
assumption that nothing running concurrently cares about the cwd,
might come back to bite us when the future (2) arrives.  But I don't
see a better approach.

Follow-on ideas: on platforms that support it, it would be nice to use

	ctx->orig_dirfd = open(".", O_RDONLY);
	if (ctx->orig_dirfd < 0)
		... error handling ...
	...
	if (ctx->orig_dirfd >= 0) {
		if (fchdir(ctx->orig_dirfd))
			die_errno("unable to restore original working directory");
		close(ctx->orig_dirfd);
	}

> --- a/unix-socket.c
> +++ b/unix-socket.c
> @@ -9,27 +9,86 @@ static int unix_stream_socket(void)
[...]
> +		dir = path;
> +		dir_len = slash - path;
[...]
> +		if (chdir_len(dir, dir_len) < 0)
> +			return -1;

Could avoid some complication by eliminating the dir_len var.

		if (chdir_len(dir, slash - dir))
			return -1;

Neither seems worth holding up the patch, so
Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>

Re: [PATCHv3 10/13] credentials: add "cache" helper

[Jeff King]

On Tue, Jan 10, 2012 at 11:44:21AM -0600, Jonathan Nieder wrote:

> Jeff King wrote:
> 
> >   2. A hack in credential-cache won't help any unix-socket
> >      users who come along later.
> >
> >   3. The chdir trickery isn't that likely to fail (basically
> >      it's only a problem if your cwd is missing or goes away
> >      while you're running).  And because we only enable the
> >      hack when we get a too-long name, it can only fail in
> >      cases that would have failed under the previous code
> >      anyway.
> >
> > Signed-off-by: Jeff King <peff@peff.net>
> 
> A part of me worries that this assumption (3), and the additional
> assumption that nothing running concurrently cares about the cwd,
> might come back to bite us when the future (2) arrives.  But I don't
> see a better approach.

The problem is that when future (2) arrives, a credential-cache specific
hack won't be helping it at all. :)

To be honest, I don't really expect a lot of future unix-socket users.
It's not portable, and most of our IPC happens over pipes. The design of
the cache daemon is very specific in requiring a true
many-clients-to-one-server model, but also caring deeply about access
controls (making TCP sockets less good[1]).

[1] One could in theory do a loopback TCP socket and provide a random
    token read from an access-controlled file. But that ends up a lot
    more complicated and introduces new attack surfaces. Which is a bad
    thing for security-sensitive code like this.

> Follow-on ideas: on platforms that support it, it would be nice to use
> 
> 	ctx->orig_dirfd = open(".", O_RDONLY);
> 	if (ctx->orig_dirfd < 0)
> 		... error handling ...
> 	...
> 	if (ctx->orig_dirfd >= 0) {
> 		if (fchdir(ctx->orig_dirfd))
> 			die_errno("unable to restore original working directory");
> 		close(ctx->orig_dirfd);
> 	}

Yeah, I started by using fchdir, but noticed that we don't use it
anywhere else and didn't want to create a portability problem. It does
fix the "somebody deleted your cwd while you were gone from it" problem.
But if you have no cwd at all, the open call will still fail.

Still, it would be slightly more robust. I wonder how portable fchdir
is in practice (I guess we could always fall back to the getcwd code
path). Do you want to prepare a patch on top?

> [...]
> > +		dir = path;
> > +		dir_len = slash - path;
> [...]
> > +		if (chdir_len(dir, dir_len) < 0)
> > +			return -1;
> 
> Could avoid some complication by eliminating the dir_len var.
> 
> 		if (chdir_len(dir, slash - dir))
> 			return -1;

Ah, yeah. Originally I had written it so that "slash" didn't survive
untouched to there, but in the current code, that would work.

Junio, if you haven't merged it to next yet, it might be worth squashing
in the patch below. Otherwise I wouldn't worry about it.

> Neither seems worth holding up the patch, so
> Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>

Thanks for the review (and for, as usual, a well-written bug report).

---
diff --git a/unix-socket.c b/unix-socket.c
index 91ed9dc..e8f19c6 100644
--- a/unix-socket.c
+++ b/unix-socket.c
@@ -43,7 +43,6 @@ static int unix_sockaddr_init(struct sockaddr_un *sa, const char *path,
 	if (size > sizeof(sa->sun_path)) {
 		const char *slash = find_last_dir_sep(path);
 		const char *dir;
-		int dir_len;
 
 		if (!slash) {
 			errno = ENAMETOOLONG;
@@ -51,8 +50,6 @@ static int unix_sockaddr_init(struct sockaddr_un *sa, const char *path,
 		}
 
 		dir = path;
-		dir_len = slash - path;
-
 		path = slash + 1;
 		size = strlen(path) + 1;
 		if (size > sizeof(sa->sun_path)) {
@@ -64,7 +61,7 @@ static int unix_sockaddr_init(struct sockaddr_un *sa, const char *path,
 			errno = ENAMETOOLONG;
 			return -1;
 		}
-		if (chdir_len(dir, dir_len) < 0)
+		if (chdir_len(dir, slash - dir) < 0)
 			return -1;
 	}
 

Re: [PATCHv3 10/13] credentials: add "cache" helper

[Jonathan Nieder]

Jeff King wrote:

> Still, it would be slightly more robust. I wonder how portable fchdir
> is in practice (I guess we could always fall back to the getcwd code
> path). Do you want to prepare a patch on top?

I've been wanting to get around to doing something similar for setup.c
for a while.  I'm happy enough to forget about it for now. ;-)

Thanks again for the fix.  Here's another quick nit.

-- >8 --
Subject: unix-socket: do not let close() or chdir() clobber errno during cleanup

unix_stream_connect and unix_stream_listen return -1 on error, with
errno set by the failing underlying call to allow the caller to write
a useful diagnosis.

Unfortunately the error path involves a few system calls itself, such
as close(), that can themselves touch errno.

This is not as worrisome as it might sound.  If close() fails, this
just means substituting one meaningful error message for another,
which is perfectly fine.  However, when the call _succeeds_, it is
allowed to (and sometimes might) clobber errno along the way with some
undefined value, so it is good higiene to save errno and restore it
immediately before returning to the caller.  Do so.

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 unix-socket.c |   39 ++++++++++++++++++++++-----------------
 1 files changed, 22 insertions(+), 17 deletions(-)

diff --git a/unix-socket.c b/unix-socket.c
index 7d8bec61..01f119f9 100644
--- a/unix-socket.c
+++ b/unix-socket.c
@@ -73,25 +73,29 @@ static int unix_sockaddr_init(struct sockaddr_un *sa, const char *path,
 
 int unix_stream_connect(const char *path)
 {
-	int fd;
+	int fd, saved_errno;
 	struct sockaddr_un sa;
 	struct unix_sockaddr_context ctx;
 
 	if (unix_sockaddr_init(&sa, path, &ctx) < 0)
 		return -1;
 	fd = unix_stream_socket();
-	if (connect(fd, (struct sockaddr *)&sa, sizeof(sa)) < 0) {
-		unix_sockaddr_cleanup(&ctx);
-		close(fd);
-		return -1;
-	}
+	if (connect(fd, (struct sockaddr *)&sa, sizeof(sa)) < 0)
+		goto fail;
 	unix_sockaddr_cleanup(&ctx);
 	return fd;
+
+fail:
+	saved_errno = errno;
+	unix_sockaddr_cleanup(&ctx);
+	close(fd);
+	errno = saved_errno;
+	return -1;
 }
 
 int unix_stream_listen(const char *path)
 {
-	int fd;
+	int fd, saved_errno;
 	struct sockaddr_un sa;
 	struct unix_sockaddr_context ctx;
 
@@ -100,18 +104,19 @@ int unix_stream_listen(const char *path)
 	fd = unix_stream_socket();
 
 	unlink(path);
-	if (bind(fd, (struct sockaddr *)&sa, sizeof(sa)) < 0) {
-		unix_sockaddr_cleanup(&ctx);
-		close(fd);
-		return -1;
-	}
+	if (bind(fd, (struct sockaddr *)&sa, sizeof(sa)) < 0)
+		goto fail;
 
-	if (listen(fd, 5) < 0) {
-		unix_sockaddr_cleanup(&ctx);
-		close(fd);
-		return -1;
-	}
+	if (listen(fd, 5) < 0)
+		goto fail;
 
 	unix_sockaddr_cleanup(&ctx);
 	return fd;
+
+fail:
+	saved_errno = errno;
+	unix_sockaddr_cleanup(&ctx);
+	close(fd);
+	errno = saved_errno;
+	return -1;
 }
-- 
1.7.8.3

Re: [PATCHv3 10/13] credentials: add "cache" helper

[Jeff King]

On Wed, Jan 11, 2012 at 05:50:10PM -0600, Jonathan Nieder wrote:

> Thanks again for the fix.  Here's another quick nit.

My favorite form for nits to come in: a patch.

> -- >8 --
> Subject: unix-socket: do not let close() or chdir() clobber errno during cleanup
> [...]

Looks good to me. Thanks.

-Peff

[PATCHv3 11/13] strbuf: add strbuf_add*_urlencode

[Jeff King]

This just follows the rfc3986 rules for percent-encoding
url data into a strbuf.

Signed-off-by: Jeff King <peff@peff.net>
---
 strbuf.c |   37 +++++++++++++++++++++++++++++++++++++
 strbuf.h |    5 +++++
 2 files changed, 42 insertions(+), 0 deletions(-)

diff --git a/strbuf.c b/strbuf.c
index a849705..ff0b96b 100644
--- a/strbuf.c
+++ b/strbuf.c
@@ -411,3 +411,40 @@ void strbuf_add_lines(struct strbuf *out, const char *prefix,
 	}
 	strbuf_complete_line(out);
 }
+
+static int is_rfc3986_reserved(char ch)
+{
+	switch (ch) {
+		case '!': case '*': case '\'': case '(': case ')': case ';':
+		case ':': case '@': case '&': case '=': case '+': case '$':
+		case ',': case '/': case '?': case '#': case '[': case ']':
+			return 1;
+	}
+	return 0;
+}
+
+static int is_rfc3986_unreserved(char ch)
+{
+	return isalnum(ch) ||
+		ch == '-' || ch == '_' || ch == '.' || ch == '~';
+}
+
+void strbuf_add_urlencode(struct strbuf *sb, const char *s, size_t len,
+			  int reserved)
+{
+	strbuf_grow(sb, len);
+	while (len--) {
+		char ch = *s++;
+		if (is_rfc3986_unreserved(ch) ||
+		    (!reserved && is_rfc3986_reserved(ch)))
+			strbuf_addch(sb, ch);
+		else
+			strbuf_addf(sb, "%%%02x", ch);
+	}
+}
+
+void strbuf_addstr_urlencode(struct strbuf *sb, const char *s,
+			     int reserved)
+{
+	strbuf_add_urlencode(sb, s, strlen(s), reserved);
+}
diff --git a/strbuf.h b/strbuf.h
index 08fc13d..fbf059f 100644
--- a/strbuf.h
+++ b/strbuf.h
@@ -123,4 +123,9 @@ static inline void strbuf_complete_line(struct strbuf *sb)
 extern int strbuf_branchname(struct strbuf *sb, const char *name);
 extern int strbuf_check_branch_ref(struct strbuf *sb, const char *name);
 
+extern void strbuf_add_urlencode(struct strbuf *, const char *, size_t,
+				 int reserved);
+extern void strbuf_addstr_urlencode(struct strbuf *, const char *,
+				    int reserved);
+
 #endif /* STRBUF_H */
-- 
1.7.8.rc2.40.gaf387

Re: [PATCHv3 11/13] strbuf: add strbuf_add*_urlencode

[Jakub Narebski]

Jeff King <peff@peff.net> writes:

> +void strbuf_add_urlencode(struct strbuf *sb, const char *s, size_t len,
> +			  int reserved)
> +{
> +	strbuf_grow(sb, len);

What is this `reserved` flag for, and when should one use it?
It would be nice to have a short comment...

BTW. was it meant to be aligned like this?

> +void strbuf_add_urlencode(struct strbuf *sb, const char *s, size_t len,
> +			     int reserved)


-- 
Jakub Narębski

Re: [PATCHv3 11/13] strbuf: add strbuf_add*_urlencode

[Jeff King]

On Sat, Dec 10, 2011 at 03:57:59AM -0800, Jakub Narebski wrote:

> Jeff King <peff@peff.net> writes:
> 
> > +void strbuf_add_urlencode(struct strbuf *sb, const char *s, size_t len,
> > +			  int reserved)
> > +{
> > +	strbuf_grow(sb, len);
> 
> What is this `reserved` flag for, and when should one use it?
> It would be nice to have a short comment...

It indicates whether one should encode rfc3986 reserved characters. You
want to use it when encoding the host, username, and password portions
of a URL (i.e., before the "/"), but not the path (since you don't want
to encode all of the slashes). If you were breaking down the path more
(e.g., into a "query" and "fragment" portion), you would care about more
specific quoting there, but we don't; we treat everything after the
slash as an opaque blob of path.

Patch to the strbuf api documentation is below. I think it should be
squashed into patch 12/13.

> BTW. was it meant to be aligned like this?
> 
> > +void strbuf_add_urlencode(struct strbuf *sb, const char *s, size_t len,
> > +			     int reserved)

It is aligned correctly. When you ident by tabs, the "+" of the diff
gets soaked in the first tabstop, so it is off-by-one with respect to
non-tabbed input (it is off even more in the quoted section above,
because "> > +" gets soaked into the first tabstop). You can see your
version above also is misaligned when I quote it. :)

If you apply the diff, the result is as you expected.

-Peff

---
diff --git a/Documentation/technical/api-strbuf.txt b/Documentation/technical/api-strbuf.txt
index afe2759..e1ab6c5 100644
--- a/Documentation/technical/api-strbuf.txt
+++ b/Documentation/technical/api-strbuf.txt
@@ -270,3 +270,14 @@ same behaviour as well.
 	third argument can be used to set the environment which the editor is
 	run in. If the buffer is NULL the editor is launched as usual but the
 	file's contents are not read into the buffer upon completion.
+
+`strbuf_add_urlencode`::
+
+	Copy data to the end of the buffer, percent-encoding it as per
+	rfc3986. If the reserved flag is non-zero, then characters in
+	the rfc3986 reserved list are percent-encoded; otherwise, they
+	are copied literally. Characters in the rfc3986 unreserved list
+	are always copied literally. All other characters are
+	percent-encoded. Typically, one would use the reserved flag for
+	the host and user-info sections of a URL, but leave special
+	characters in the path untouched.

[PATCHv3 12/13] credentials: add "store" helper

[Jeff King]

This is like "cache", except that we actually put the
credentials on disk. This can be terribly insecure, of
course, but we do what we can to protect them by filesystem
permissions, and we warn the user in the documentation.

This is not unlike using .netrc to store entries, but it's a
little more user-friendly. Instead of putting credentials in
place ahead of time, we transparently store them after
prompting the user for them once.

Signed-off-by: Jeff King <peff@peff.net>
---
This version has the "don't erase everything" protection we discussed.

 .gitignore                             |    1 +
 Documentation/git-credential-store.txt |   75 +++++++++++++++
 Documentation/gitcredentials.txt       |    5 +
 Makefile                               |    1 +
 credential-store.c                     |  157 ++++++++++++++++++++++++++++++++
 t/t0302-credential-store.sh            |    9 ++
 6 files changed, 248 insertions(+), 0 deletions(-)
 create mode 100644 Documentation/git-credential-store.txt
 create mode 100644 credential-store.c
 create mode 100755 t/t0302-credential-store.sh

diff --git a/.gitignore b/.gitignore
index a6b0bd4..2b7a3f9 100644
--- a/.gitignore
+++ b/.gitignore
@@ -32,6 +32,7 @@
 /git-count-objects
 /git-credential-cache
 /git-credential-cache--daemon
+/git-credential-store
 /git-cvsexportcommit
 /git-cvsimport
 /git-cvsserver
diff --git a/Documentation/git-credential-store.txt b/Documentation/git-credential-store.txt
new file mode 100644
index 0000000..3109346
--- /dev/null
+++ b/Documentation/git-credential-store.txt
@@ -0,0 +1,75 @@
+git-credential-store(1)
+=======================
+
+NAME
+----
+git-credential-store - helper to store credentials on disk
+
+SYNOPSIS
+--------
+-------------------
+git config credential.helper 'store [options]'
+-------------------
+
+DESCRIPTION
+-----------
+
+NOTE: Using this helper will store your passwords unencrypted on disk,
+protected only by filesystem permissions. If this is not an acceptable
+security tradeoff, try linkgit:git-credential-cache[1], or find a helper
+that integrates with secure storage provided by your operating system.
+
+This command stores credentials indefinitely on disk for use by future
+git programs.
+
+You probably don't want to invoke this command directly; it is meant to
+be used as a credential helper by other parts of git. See
+linkgit:gitcredentials[7] or `EXAMPLES` below.
+
+OPTIONS
+-------
+
+--store=<path>::
+
+	Use `<path>` to store credentials. The file will have its
+	filesystem permissions set to prevent other users on the system
+	from reading it, but will not be encrypted or otherwise
+	protected. Defaults to `~/.git-credentials`.
+
+EXAMPLES
+--------
+
+The point of this helper is to reduce the number of times you must type
+your username or password. For example:
+
+------------------------------------------
+$ git config credential.helper store
+$ git push http://example.com/repo.git
+Username: <type your username>
+Password: <type your password>
+
+[several days later]
+$ git push http://example.com/repo.git
+[your credentials are used automatically]
+------------------------------------------
+
+STORAGE FORMAT
+--------------
+
+The `.git-credentials` file is stored in plaintext. Each credential is
+stored on its own line as a URL like:
+
+------------------------------
+https://user:pass@example.com
+------------------------------
+
+When git needs authentication for a particular URL context,
+credential-store will consider that context a pattern to match against
+each entry in the credentials file.  If the protocol, hostname, and
+username (if we already have one) match, then the password is returned
+to git. See the discussion of configuration in linkgit:gitcredentials[7]
+for more information.
+
+GIT
+---
+Part of the linkgit:git[1] suite
diff --git a/Documentation/gitcredentials.txt b/Documentation/gitcredentials.txt
index 4e3f860..066f825 100644
--- a/Documentation/gitcredentials.txt
+++ b/Documentation/gitcredentials.txt
@@ -71,6 +71,11 @@ cache::
 	Cache credentials in memory for a short period of time. See
 	linkgit:git-credential-cache[1] for details.
 
+store::
+
+	Store credentials indefinitely on disk. See
+	linkgit:git-credential-store[1] for details.
+
 You may also have third-party helpers installed; search for
 `credential-*` in the output of `git help -a`, and consult the
 documentation of individual helpers.  Once you have selected a helper,
diff --git a/Makefile b/Makefile
index 7ad2fe3..b144f1a 100644
--- a/Makefile
+++ b/Makefile
@@ -429,6 +429,7 @@ PROGRAM_OBJS += http-backend.o
 PROGRAM_OBJS += sh-i18n--envsubst.o
 PROGRAM_OBJS += credential-cache.o
 PROGRAM_OBJS += credential-cache--daemon.o
+PROGRAM_OBJS += credential-store.o
 
 PROGRAMS += $(patsubst %.o,git-%$X,$(PROGRAM_OBJS))
 
diff --git a/credential-store.c b/credential-store.c
new file mode 100644
index 0000000..26f7589
--- /dev/null
+++ b/credential-store.c
@@ -0,0 +1,157 @@
+#include "cache.h"
+#include "credential.h"
+#include "string-list.h"
+#include "parse-options.h"
+
+static struct lock_file credential_lock;
+
+static void parse_credential_file(const char *fn,
+				  struct credential *c,
+				  void (*match_cb)(struct credential *),
+				  void (*other_cb)(struct strbuf *))
+{
+	FILE *fh;
+	struct strbuf line = STRBUF_INIT;
+	struct credential entry = CREDENTIAL_INIT;
+
+	fh = fopen(fn, "r");
+	if (!fh) {
+		if (errno != ENOENT)
+			die_errno("unable to open %s", fn);
+		return;
+	}
+
+	while (strbuf_getline(&line, fh, '\n') != EOF) {
+		credential_from_url(&entry, line.buf);
+		if (entry.username && entry.password &&
+		    credential_match(c, &entry)) {
+			if (match_cb) {
+				match_cb(&entry);
+				break;
+			}
+		}
+		else if (other_cb)
+			other_cb(&line);
+	}
+
+	credential_clear(&entry);
+	strbuf_release(&line);
+	fclose(fh);
+}
+
+static void print_entry(struct credential *c)
+{
+	printf("username=%s\n", c->username);
+	printf("password=%s\n", c->password);
+}
+
+static void print_line(struct strbuf *buf)
+{
+	strbuf_addch(buf, '\n');
+	write_or_die(credential_lock.fd, buf->buf, buf->len);
+}
+
+static void rewrite_credential_file(const char *fn, struct credential *c,
+				    struct strbuf *extra)
+{
+	if (hold_lock_file_for_update(&credential_lock, fn, 0) < 0)
+		die_errno("unable to get credential storage lock");
+	if (extra)
+		print_line(extra);
+	parse_credential_file(fn, c, NULL, print_line);
+	if (commit_lock_file(&credential_lock) < 0)
+		die_errno("unable to commit credential store");
+}
+
+static void store_credential(const char *fn, struct credential *c)
+{
+	struct strbuf buf = STRBUF_INIT;
+
+	/*
+	 * Sanity check that what we are storing is actually sensible.
+	 * In particular, we can't make a URL without a protocol field.
+	 * Without either a host or pathname (depending on the scheme),
+	 * we have no primary key. And without a username and password,
+	 * we are not actually storing a credential.
+	 */
+	if (!c->protocol || !(c->host || c->path) ||
+	    !c->username || !c->password)
+		return;
+
+	strbuf_addf(&buf, "%s://", c->protocol);
+	strbuf_addstr_urlencode(&buf, c->username, 1);
+	strbuf_addch(&buf, ':');
+	strbuf_addstr_urlencode(&buf, c->password, 1);
+	strbuf_addch(&buf, '@');
+	if (c->host)
+		strbuf_addstr_urlencode(&buf, c->host, 1);
+	if (c->path) {
+		strbuf_addch(&buf, '/');
+		strbuf_addstr_urlencode(&buf, c->path, 0);
+	}
+
+	rewrite_credential_file(fn, c, &buf);
+	strbuf_release(&buf);
+}
+
+static void remove_credential(const char *fn, struct credential *c)
+{
+	/*
+	 * Sanity check that we actually have something to match
+	 * against. The input we get is a restrictive pattern,
+	 * so technically a blank credential means "erase everything".
+	 * But it is too easy to accidentally send this, since it is equivalent
+	 * to empty input. So explicitly disallow it, and require that the
+	 * pattern have some actual content to match.
+	 */
+	if (c->protocol || c->host || c->path || c->username)
+		rewrite_credential_file(fn, c, NULL);
+}
+
+static int lookup_credential(const char *fn, struct credential *c)
+{
+	parse_credential_file(fn, c, print_entry, NULL);
+	return c->username && c->password;
+}
+
+int main(int argc, const char **argv)
+{
+	const char * const usage[] = {
+		"git credential-store [options] <action>",
+		NULL
+	};
+	const char *op;
+	struct credential c = CREDENTIAL_INIT;
+	char *file = NULL;
+	struct option options[] = {
+		OPT_STRING(0, "file", &file, "path",
+			   "fetch and store credentials in <path>"),
+		OPT_END()
+	};
+
+	umask(077);
+
+	argc = parse_options(argc, argv, NULL, options, usage, 0);
+	if (argc != 1)
+		usage_with_options(usage, options);
+	op = argv[0];
+
+	if (!file)
+		file = expand_user_path("~/.git-credentials");
+	if (!file)
+		die("unable to set up default path; use --file");
+
+	if (credential_read(&c, stdin) < 0)
+		die("unable to read credential");
+
+	if (!strcmp(op, "get"))
+		lookup_credential(file, &c);
+	else if (!strcmp(op, "erase"))
+		remove_credential(file, &c);
+	else if (!strcmp(op, "store"))
+		store_credential(file, &c);
+	else
+		; /* Ignore unknown operation. */
+
+	return 0;
+}
diff --git a/t/t0302-credential-store.sh b/t/t0302-credential-store.sh
new file mode 100755
index 0000000..f61b40c
--- /dev/null
+++ b/t/t0302-credential-store.sh
@@ -0,0 +1,9 @@
+#!/bin/sh
+
+test_description='credential-store tests'
+. ./test-lib.sh
+. "$TEST_DIRECTORY"/lib-credential.sh
+
+helper_test store
+
+test_done
-- 
1.7.8.rc2.40.gaf387

[PATCHv3 13/13] t: add test harness for external credential helpers

[Jeff King]

We already have tests for the internal helpers, but it's
nice to give authors of external tools an easy way to
sanity-check their helpers.

If you have written the "git-credential-foo" helper, you can
do so with:

  GIT_TEST_CREDENTIAL_HELPER=foo \
  make t0303-credential-external.sh

This assumes that your helper is capable of both storing and
retrieving credentials (some helpers may be read-only, and
they will fail these tests).

If your helper supports time-based expiration with a
configurable timeout, you can test that feature like this:

  GIT_TEST_CREDENTIAL_HELPER_TIMEOUT="foo --timeout=1" \
  make t0303-credential-external.sh

Signed-off-by: Jeff King <peff@peff.net>
---
This version adds GIT_TEST_CREDENTIAL_HELPER_SETUP, which is an
unfortunate hack needed for the OS X helper (I'll post that patch in a
few minutes).

 t/t0303-credential-external.sh |   39 +++++++++++++++++++++++++++++++++++++++
 1 files changed, 39 insertions(+), 0 deletions(-)
 create mode 100755 t/t0303-credential-external.sh

diff --git a/t/t0303-credential-external.sh b/t/t0303-credential-external.sh
new file mode 100755
index 0000000..267f4c8
--- /dev/null
+++ b/t/t0303-credential-external.sh
@@ -0,0 +1,39 @@
+#!/bin/sh
+
+test_description='external credential helper tests'
+. ./test-lib.sh
+. "$TEST_DIRECTORY"/lib-credential.sh
+
+pre_test() {
+	test -z "$GIT_TEST_CREDENTIAL_HELPER_SETUP" ||
+	eval "$GIT_TEST_CREDENTIAL_HELPER_SETUP"
+
+	# clean before the test in case there is cruft left
+	# over from a previous run that would impact results
+	helper_test_clean "$GIT_TEST_CREDENTIAL_HELPER"
+}
+
+post_test() {
+	# clean afterwards so that we are good citizens
+	# and don't leave cruft in the helper's storage, which
+	# might be long-term system storage
+	helper_test_clean "$GIT_TEST_CREDENTIAL_HELPER"
+}
+
+if test -z "$GIT_TEST_CREDENTIAL_HELPER"; then
+	say "# skipping external helper tests (set GIT_TEST_CREDENTIAL_HELPER)"
+else
+	pre_test
+	helper_test "$GIT_TEST_CREDENTIAL_HELPER"
+	post_test
+fi
+
+if test -z "$GIT_TEST_CREDENTIAL_HELPER_TIMEOUT"; then
+	say "# skipping external helper timeout tests"
+else
+	pre_test
+	helper_test_timeout "$GIT_TEST_CREDENTIAL_HELPER_TIMEOUT"
+	post_test
+fi
+
+test_done
-- 
1.7.8.rc2.40.gaf387

[PATCHv2 0/9] echo characters in username prompt

[Jeff King]

On Sat, Dec 10, 2011 at 05:28:27AM -0500, Jeff King wrote:

> Here's the latest re-roll of the credential helpers series. I think this
> one is probably ready to go to 'next'.

And here's the prompt/terminal refactoring to go on top of it. This
isn't as well reviewed as the main credential series, but I think it's
reasonably solid.

Since the last round, I fixed the bone-head NO_DEV_TTY/HAVE_DEV_TTY
mixup that Jakub pointed out. And I split the "Linux has /dev/tty" patch
out so I could test to make sure it isn't accidentally turned on until
we actually enable it.

I also tested it on OS X, and it works fine there.

  [1/9]: imap-send: avoid buffer overflow
  [2/9]: imap-send: don't check return value of git_getpass
  [3/9]: move git_getpass to its own source file
  [4/9]: refactor git_getpass into generic prompt function
  [5/9]: add generic terminal prompt function
  [6/9]: prompt: use git_terminal_prompt
  [7/9]: credential: use git_prompt instead of git_getpass
  [8/9]: Makefile: linux has /dev/tty
  [9/9]: Makefile: OS X has /dev/tty

-Peff

[PATCHv2 1/9] imap-send: avoid buffer overflow

[Jeff King]

We format the password prompt in an 80-character static
buffer. It contains the remote host and username, so it's
unlikely to overflow (or be exploitable by a remote
attacker), but there's no reason not to be careful and use
a strbuf.

Signed-off-by: Jeff King <peff@peff.net>
---
 imap-send.c |    7 ++++---
 1 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/imap-send.c b/imap-send.c
index e1ad1a4..4c1e897 100644
--- a/imap-send.c
+++ b/imap-send.c
@@ -1209,9 +1209,10 @@ static int auth_cram_md5(struct imap_store *ctx, struct imap_cmd *cmd, const cha
 			goto bail;
 		}
 		if (!srvc->pass) {
-			char prompt[80];
-			sprintf(prompt, "Password (%s@%s): ", srvc->user, srvc->host);
-			arg = git_getpass(prompt);
+			struct strbuf prompt = STRBUF_INIT;
+			strbuf_addf(&prompt, "Password (%s@%s): ", srvc->user, srvc->host);
+			arg = git_getpass(prompt.buf);
+			strbuf_release(&prompt);
 			if (!arg) {
 				perror("getpass");
 				exit(1);
-- 
1.7.8.rc2.40.gaf387

[PATCHv2 2/9] imap-send: don't check return value of git_getpass

[Jeff King]

git_getpass will always die() if we weren't able to get
input, so there's no point looking for NULL.

Signed-off-by: Jeff King <peff@peff.net>
---
 imap-send.c |    4 ----
 1 files changed, 0 insertions(+), 4 deletions(-)

diff --git a/imap-send.c b/imap-send.c
index 4c1e897..227253e 100644
--- a/imap-send.c
+++ b/imap-send.c
@@ -1213,10 +1213,6 @@ static int auth_cram_md5(struct imap_store *ctx, struct imap_cmd *cmd, const cha
 			strbuf_addf(&prompt, "Password (%s@%s): ", srvc->user, srvc->host);
 			arg = git_getpass(prompt.buf);
 			strbuf_release(&prompt);
-			if (!arg) {
-				perror("getpass");
-				exit(1);
-			}
 			if (!*arg) {
 				fprintf(stderr, "Skipping account %s@%s, no password\n", srvc->user, srvc->host);
 				goto bail;
-- 
1.7.8.rc2.40.gaf387

[PATCHv2 3/9] move git_getpass to its own source file

[Jeff King]

This is currently in connect.c, but really has nothing to
do with the git protocol itself. Let's make a new source
file all about prompting the user, which will make it
cleaner to refactor.

Signed-off-by: Jeff King <peff@peff.net>
---
 Makefile     |    2 ++
 cache.h      |    1 -
 connect.c    |   44 --------------------------------------------
 credential.c |    1 +
 imap-send.c  |    1 +
 prompt.c     |   48 ++++++++++++++++++++++++++++++++++++++++++++++++
 prompt.h     |    6 ++++++
 7 files changed, 58 insertions(+), 45 deletions(-)
 create mode 100644 prompt.c
 create mode 100644 prompt.h

diff --git a/Makefile b/Makefile
index b144f1a..5201bea 100644
--- a/Makefile
+++ b/Makefile
@@ -565,6 +565,7 @@ LIB_H += parse-options.h
 LIB_H += patch-ids.h
 LIB_H += pkt-line.h
 LIB_H += progress.h
+LIB_H += prompt.h
 LIB_H += quote.h
 LIB_H += reflog-walk.h
 LIB_H += refs.h
@@ -672,6 +673,7 @@ LIB_OBJS += pkt-line.o
 LIB_OBJS += preload-index.o
 LIB_OBJS += pretty.o
 LIB_OBJS += progress.o
+LIB_OBJS += prompt.o
 LIB_OBJS += quote.o
 LIB_OBJS += reachable.o
 LIB_OBJS += read-cache.o
diff --git a/cache.h b/cache.h
index 8c98d05..bb26c2f 100644
--- a/cache.h
+++ b/cache.h
@@ -1025,7 +1025,6 @@ struct ref {
 extern struct ref *find_ref_by_name(const struct ref *list, const char *name);
 
 #define CONNECT_VERBOSE       (1u << 0)
-extern char *git_getpass(const char *prompt);
 extern struct child_process *git_connect(int fd[2], const char *url, const char *prog, int flags);
 extern int finish_connect(struct child_process *conn);
 extern int git_connection_is_socket(struct child_process *conn);
diff --git a/connect.c b/connect.c
index 51990fa..519e527 100644
--- a/connect.c
+++ b/connect.c
@@ -619,47 +619,3 @@ int finish_connect(struct child_process *conn)
 	free(conn);
 	return code;
 }
-
-char *git_getpass(const char *prompt)
-{
-	const char *askpass;
-	struct child_process pass;
-	const char *args[3];
-	static struct strbuf buffer = STRBUF_INIT;
-
-	askpass = getenv("GIT_ASKPASS");
-	if (!askpass)
-		askpass = askpass_program;
-	if (!askpass)
-		askpass = getenv("SSH_ASKPASS");
-	if (!askpass || !(*askpass)) {
-		char *result = getpass(prompt);
-		if (!result)
-			die_errno("Could not read password");
-		return result;
-	}
-
-	args[0] = askpass;
-	args[1]	= prompt;
-	args[2] = NULL;
-
-	memset(&pass, 0, sizeof(pass));
-	pass.argv = args;
-	pass.out = -1;
-
-	if (start_command(&pass))
-		exit(1);
-
-	strbuf_reset(&buffer);
-	if (strbuf_read(&buffer, pass.out, 20) < 0)
-		die("failed to read password from %s\n", askpass);
-
-	close(pass.out);
-
-	if (finish_command(&pass))
-		exit(1);
-
-	strbuf_setlen(&buffer, strcspn(buffer.buf, "\r\n"));
-
-	return buffer.buf;
-}
diff --git a/credential.c b/credential.c
index a17eafe..fbb7231 100644
--- a/credential.c
+++ b/credential.c
@@ -3,6 +3,7 @@
 #include "string-list.h"
 #include "run-command.h"
 #include "url.h"
+#include "prompt.h"
 
 void credential_init(struct credential *c)
 {
diff --git a/imap-send.c b/imap-send.c
index 227253e..43588e8 100644
--- a/imap-send.c
+++ b/imap-send.c
@@ -25,6 +25,7 @@
 #include "cache.h"
 #include "exec_cmd.h"
 #include "run-command.h"
+#include "prompt.h"
 #ifdef NO_OPENSSL
 typedef void *SSL;
 #else
diff --git a/prompt.c b/prompt.c
new file mode 100644
index 0000000..42a1c9f
--- /dev/null
+++ b/prompt.c
@@ -0,0 +1,48 @@
+#include "cache.h"
+#include "run-command.h"
+#include "strbuf.h"
+#include "prompt.h"
+
+char *git_getpass(const char *prompt)
+{
+	const char *askpass;
+	struct child_process pass;
+	const char *args[3];
+	static struct strbuf buffer = STRBUF_INIT;
+
+	askpass = getenv("GIT_ASKPASS");
+	if (!askpass)
+		askpass = askpass_program;
+	if (!askpass)
+		askpass = getenv("SSH_ASKPASS");
+	if (!askpass || !(*askpass)) {
+		char *result = getpass(prompt);
+		if (!result)
+			die_errno("Could not read password");
+		return result;
+	}
+
+	args[0] = askpass;
+	args[1]	= prompt;
+	args[2] = NULL;
+
+	memset(&pass, 0, sizeof(pass));
+	pass.argv = args;
+	pass.out = -1;
+
+	if (start_command(&pass))
+		exit(1);
+
+	strbuf_reset(&buffer);
+	if (strbuf_read(&buffer, pass.out, 20) < 0)
+		die("failed to read password from %s\n", askpass);
+
+	close(pass.out);
+
+	if (finish_command(&pass))
+		exit(1);
+
+	strbuf_setlen(&buffer, strcspn(buffer.buf, "\r\n"));
+
+	return buffer.buf;
+}
diff --git a/prompt.h b/prompt.h
new file mode 100644
index 0000000..0fd7bd9
--- /dev/null
+++ b/prompt.h
@@ -0,0 +1,6 @@
+#ifndef PROMPT_H
+#define PROMPT_H
+
+char *git_getpass(const char *prompt);
+
+#endif /* PROMPT_H */
-- 
1.7.8.rc2.40.gaf387

[PATCHv2 4/9] refactor git_getpass into generic prompt function

[Jeff King]

This will allow callers to specify more options (e.g.,
leaving echo on). The original git_getpass becomes a slim
wrapper around the new function.

Signed-off-by: Jeff King <peff@peff.net>
---
 prompt.c |   46 ++++++++++++++++++++++++++++++----------------
 prompt.h |    3 +++
 2 files changed, 33 insertions(+), 16 deletions(-)

diff --git a/prompt.c b/prompt.c
index 42a1c9f..2002644 100644
--- a/prompt.c
+++ b/prompt.c
@@ -3,26 +3,13 @@
 #include "strbuf.h"
 #include "prompt.h"
 
-char *git_getpass(const char *prompt)
+static char *do_askpass(const char *cmd, const char *prompt)
 {
-	const char *askpass;
 	struct child_process pass;
 	const char *args[3];
 	static struct strbuf buffer = STRBUF_INIT;
 
-	askpass = getenv("GIT_ASKPASS");
-	if (!askpass)
-		askpass = askpass_program;
-	if (!askpass)
-		askpass = getenv("SSH_ASKPASS");
-	if (!askpass || !(*askpass)) {
-		char *result = getpass(prompt);
-		if (!result)
-			die_errno("Could not read password");
-		return result;
-	}
-
-	args[0] = askpass;
+	args[0] = cmd;
 	args[1]	= prompt;
 	args[2] = NULL;
 
@@ -35,7 +22,7 @@
 
 	strbuf_reset(&buffer);
 	if (strbuf_read(&buffer, pass.out, 20) < 0)
-		die("failed to read password from %s\n", askpass);
+		die("failed to get '%s' from %s\n", prompt, cmd);
 
 	close(pass.out);
 
@@ -46,3 +33,30 @@
 
 	return buffer.buf;
 }
+
+char *git_prompt(const char *prompt, int flags)
+{
+	char *r;
+
+	if (flags & PROMPT_ASKPASS) {
+		const char *askpass;
+
+		askpass = getenv("GIT_ASKPASS");
+		if (!askpass)
+			askpass = askpass_program;
+		if (!askpass)
+			askpass = getenv("SSH_ASKPASS");
+		if (askpass && *askpass)
+			return do_askpass(askpass, prompt);
+	}
+
+	r = getpass(prompt);
+	if (!r)
+		die_errno("could not read '%s'", prompt);
+	return r;
+}
+
+char *git_getpass(const char *prompt)
+{
+	return git_prompt(prompt, PROMPT_ASKPASS);
+}
diff --git a/prompt.h b/prompt.h
index 0fd7bd9..9ab85a7 100644
--- a/prompt.h
+++ b/prompt.h
@@ -1,6 +1,9 @@
 #ifndef PROMPT_H
 #define PROMPT_H
 
+#define PROMPT_ASKPASS (1<<0)
+
+char *git_prompt(const char *prompt, int flags);
 char *git_getpass(const char *prompt);
 
 #endif /* PROMPT_H */
-- 
1.7.8.rc2.40.gaf387

[PATCHv2 5/9] add generic terminal prompt function

[Jeff King]

When we need to prompt the user for input interactively, we
want to access their terminal directly. We can't rely on
stdio because it may be connected to pipes or files, rather
than the terminal. Instead, we use "getpass()", because it
abstracts the idea of prompting and reading from the
terminal.  However, it has some problems:

  1. It never echoes the typed characters, which makes it OK
     for passwords but annoying for other input (like usernames).

  2. Some implementations of getpass() have an extremely
     small input buffer (e.g., Solaris 8 is reported to
     support only 8 characters).

  3. Some implementations of getpass() will fall back to
     reading from stdin (e.g., glibc). We explicitly don't
     want this, because our stdin may be connected to a pipe
     speaking a particular protocol, and reading will
     disrupt the protocol flow (e.g., the remote-curl
     helper).

  4. Some implementations of getpass() turn off signals, so
     that hitting "^C" on the terminal does not break out of
     the password prompt. This can be a mild annoyance.

Instead, let's provide an abstract "git_terminal_prompt"
function that addresses these concerns. This patch includes
an implementation based on /dev/tty, enabled by setting
HAVE_DEV_TTY. The fallback is to use getpass() as before.

Signed-off-by: Jeff King <peff@peff.net>
---
 Makefile          |    9 ++++++
 compat/terminal.c |   81 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 compat/terminal.h |    6 ++++
 3 files changed, 96 insertions(+), 0 deletions(-)
 create mode 100644 compat/terminal.c
 create mode 100644 compat/terminal.h

diff --git a/Makefile b/Makefile
index 5201bea..4ef6ba5 100644
--- a/Makefile
+++ b/Makefile
@@ -227,6 +227,9 @@ all::
 #
 # Define NO_REGEX if you have no or inferior regex support in your C library.
 #
+# Define HAVE_DEV_TTY if your system can open /dev/tty to interact with the
+# user.
+#
 # Define GETTEXT_POISON if you are debugging the choice of strings marked
 # for translation.  In a GETTEXT_POISON build, you can turn all strings marked
 # for translation into gibberish by setting the GIT_GETTEXT_POISON variable
@@ -523,6 +526,7 @@ LIB_H += compat/bswap.h
 LIB_H += compat/cygwin.h
 LIB_H += compat/mingw.h
 LIB_H += compat/obstack.h
+LIB_H += compat/terminal.h
 LIB_H += compat/win32/pthread.h
 LIB_H += compat/win32/syslog.h
 LIB_H += compat/win32/poll.h
@@ -612,6 +616,7 @@ LIB_OBJS += color.o
 LIB_OBJS += combine-diff.o
 LIB_OBJS += commit.o
 LIB_OBJS += compat/obstack.o
+LIB_OBJS += compat/terminal.o
 LIB_OBJS += config.o
 LIB_OBJS += connect.o
 LIB_OBJS += connected.o
@@ -1642,6 +1647,10 @@ ifdef HAVE_PATHS_H
 	BASIC_CFLAGS += -DHAVE_PATHS_H
 endif
 
+ifdef HAVE_DEV_TTY
+	BASIC_CFLAGS += -DHAVE_DEV_TTY
+endif
+
 ifdef DIR_HAS_BSD_GROUP_SEMANTICS
 	COMPAT_CFLAGS += -DDIR_HAS_BSD_GROUP_SEMANTICS
 endif
diff --git a/compat/terminal.c b/compat/terminal.c
new file mode 100644
index 0000000..6d16c8f
--- /dev/null
+++ b/compat/terminal.c
@@ -0,0 +1,81 @@
+#include "git-compat-util.h"
+#include "compat/terminal.h"
+#include "sigchain.h"
+#include "strbuf.h"
+
+#ifdef HAVE_DEV_TTY
+
+static int term_fd = -1;
+static struct termios old_term;
+
+static void restore_term(void)
+{
+	if (term_fd < 0)
+		return;
+
+	tcsetattr(term_fd, TCSAFLUSH, &old_term);
+	term_fd = -1;
+}
+
+static void restore_term_on_signal(int sig)
+{
+	restore_term();
+	sigchain_pop(sig);
+	raise(sig);
+}
+
+char *git_terminal_prompt(const char *prompt, int echo)
+{
+	static struct strbuf buf = STRBUF_INIT;
+	int r;
+	FILE *fh;
+
+	fh = fopen("/dev/tty", "w+");
+	if (!fh)
+		return NULL;
+
+	if (!echo) {
+		struct termios t;
+
+		if (tcgetattr(fileno(fh), &t) < 0) {
+			fclose(fh);
+			return NULL;
+		}
+
+		old_term = t;
+		term_fd = fileno(fh);
+		sigchain_push_common(restore_term_on_signal);
+
+		t.c_lflag &= ~ECHO;
+		if (tcsetattr(fileno(fh), TCSAFLUSH, &t) < 0) {
+			term_fd = -1;
+			fclose(fh);
+			return NULL;
+		}
+	}
+
+	fputs(prompt, fh);
+	fflush(fh);
+
+	r = strbuf_getline(&buf, fh, '\n');
+	if (!echo) {
+		putc('\n', fh);
+		fflush(fh);
+	}
+
+	restore_term();
+	fclose(fh);
+
+	if (r == EOF)
+		return NULL;
+	return buf.buf;
+}
+
+#else
+
+char *git_terminal_prompt(const char *prompt, int echo)
+{
+	return getpass(prompt);
+}
+
+#endif
diff --git a/compat/terminal.h b/compat/terminal.h
new file mode 100644
index 0000000..97db7cd
--- /dev/null
+++ b/compat/terminal.h
@@ -0,0 +1,6 @@
+#ifndef COMPAT_TERMINAL_H
+#define COMPAT_TERMINAL_H
+
+char *git_terminal_prompt(const char *prompt, int echo);
+
+#endif /* COMPAT_TERMINAL_H */
-- 
1.7.8.rc2.40.gaf387

Re: [PATCHv2 5/9] add generic terminal prompt function

[Pete Wyckoff]

peff@peff.net wrote on Sat, 10 Dec 2011 05:41 -0500:
> +static struct termios old_term;
> +
> +static void restore_term(void)
> +{
> +	if (term_fd < 0)
> +		return;
> +
> +	tcsetattr(term_fd, TCSAFLUSH, &old_term);
> +	term_fd = -1;
> +}

Restores from static old_term.

> +char *git_terminal_prompt(const char *prompt, int echo)
> +{
> +	static struct strbuf buf = STRBUF_INIT;
> +	int r;
> +	FILE *fh;
> +
> +	fh = fopen("/dev/tty", "w+");
> +	if (!fh)
> +		return NULL;
> +
> +	if (!echo) {
> +		struct termios t;
> +
> +		if (tcgetattr(fileno(fh), &t) < 0) {
> +			fclose(fh);
> +			return NULL;
> +		}
> +
> +		old_term = t;

Which is only saved if echo is true.

> +		term_fd = fileno(fh);
> +		sigchain_push_common(restore_term_on_signal);
> +
> +		t.c_lflag &= ~ECHO;
> +		if (tcsetattr(fileno(fh), TCSAFLUSH, &t) < 0) {
> +			term_fd = -1;
> +			fclose(fh);
> +			return NULL;
> +		}
> +	}
> +
> +	fputs(prompt, fh);
> +	fflush(fh);
> +
> +	r = strbuf_getline(&buf, fh, '\n');
> +	if (!echo) {
> +		putc('\n', fh);
> +		fflush(fh);
> +	}
> +
> +	restore_term();

Perhaps this line should go in !echo.

And why no sigchain_pop() for the signal handler?

		-- Pete

Re: [PATCHv2 5/9] add generic terminal prompt function

[Jeff King]

On Thu, Dec 15, 2011 at 07:48:51AM -0500, Pete Wyckoff wrote:

> peff@peff.net wrote on Sat, 10 Dec 2011 05:41 -0500:
> > +static struct termios old_term;
> > +
> > +static void restore_term(void)
> > +{
> > +	if (term_fd < 0)
> > +		return;
> > +
> > +	tcsetattr(term_fd, TCSAFLUSH, &old_term);
> > +	term_fd = -1;
> > +}
> 
> Restores from static old_term.

Right. But note that it is protected by term_fd being set.

> > +char *git_terminal_prompt(const char *prompt, int echo)
> > +{
> > +	static struct strbuf buf = STRBUF_INIT;
> > +	int r;
> > +	FILE *fh;
> > +
> > +	fh = fopen("/dev/tty", "w+");
> > +	if (!fh)
> > +		return NULL;
> > +
> > +	if (!echo) {
> > +		struct termios t;
> > +
> > +		if (tcgetattr(fileno(fh), &t) < 0) {
> > +			fclose(fh);
> > +			return NULL;
> > +		}
> > +
> > +		old_term = t;
> 
> Which is only saved if echo is true.

Yes, but just below:

> > +		term_fd = fileno(fh);
> > +		sigchain_push_common(restore_term_on_signal);

We set up term_fd, and then:

> > +		t.c_lflag &= ~ECHO;
> > +		if (tcsetattr(fileno(fh), TCSAFLUSH, &t) < 0) {
> > +			term_fd = -1;
> > +			fclose(fh);
> > +			return NULL;
> > +		}

On error, disable it again.

> > +	}
> > +
> > +	fputs(prompt, fh);
> > +	fflush(fh);
> > +
> > +	r = strbuf_getline(&buf, fh, '\n');
> > +	if (!echo) {
> > +		putc('\n', fh);
> > +		fflush(fh);
> > +	}
> > +
> > +	restore_term();
> 
> Perhaps this line should go in !echo.

It could, but it's a no-op as-is, as term_fd will be -1.

I agree it might be a little more obvious to put it there (I think what
happened is my initial revision did not look at "echo" ever again, and
then that conditional was added later when I realized that the "!echo"
case needed us to print the newline manually).

> And why no sigchain_pop() for the signal handler?

Because I used sigchain_push_common, which has no pop_common analog. But
it's OK, because calling restore_term sets term_fd to -1, making further
calls a no-op. So leaving the handler in place is fine.

Another option would be to add sigchain_pop_common, which pops the
same signals from push_common.

-Peff

Re: [PATCHv2 5/9] add generic terminal prompt function

[Pete Wyckoff]

peff@peff.net wrote on Thu, 15 Dec 2011 08:39 -0500:
> I agree it might be a little more obvious to put it there (I think what
> happened is my initial revision did not look at "echo" ever again, and
> then that conditional was added later when I realized that the "!echo"
> case needed us to print the newline manually).
> 
> > And why no sigchain_pop() for the signal handler?
> 
> Because I used sigchain_push_common, which has no pop_common analog. But
> it's OK, because calling restore_term sets term_fd to -1, making further
> calls a no-op. So leaving the handler in place is fine.
> 
> Another option would be to add sigchain_pop_common, which pops the
> same signals from push_common.

Thanks for the detailed explanation.  It was indeed the lack of
symmetry that set me off.  I missed the term_fd check for both.

		-- Pete

[PATCHv2 6/9] prompt: use git_terminal_prompt

[Jeff King]

Our custom implementation of git_terminal_prompt has many
advantages over regular getpass(), as described in the prior
commit.

This also lets us implement a PROMPT_ECHO flag for callers
who want it.

Signed-off-by: Jeff King <peff@peff.net>
---
 prompt.c |    3 ++-
 prompt.h |    1 +
 2 files changed, 3 insertions(+), 1 deletions(-)

diff --git a/prompt.c b/prompt.c
index 2002644..72ab9de 100644
--- a/prompt.c
+++ b/prompt.c
@@ -2,6 +2,7 @@
 #include "run-command.h"
 #include "strbuf.h"
 #include "prompt.h"
+#include "compat/terminal.h"
 
 static char *do_askpass(const char *cmd, const char *prompt)
 {
@@ -50,7 +51,7 @@
 			return do_askpass(askpass, prompt);
 	}
 
-	r = getpass(prompt);
+	r = git_terminal_prompt(prompt, flags & PROMPT_ECHO);
 	if (!r)
 		die_errno("could not read '%s'", prompt);
 	return r;
diff --git a/prompt.h b/prompt.h
index 9ab85a7..04f321a 100644
--- a/prompt.h
+++ b/prompt.h
@@ -2,6 +2,7 @@
 #define PROMPT_H
 
 #define PROMPT_ASKPASS (1<<0)
+#define PROMPT_ECHO    (1<<1)
 
 char *git_prompt(const char *prompt, int flags);
 char *git_getpass(const char *prompt);
-- 
1.7.8.rc2.40.gaf387

[PATCHv2 7/9] credential: use git_prompt instead of git_getpass

[Jeff King]

We use git_getpass to retrieve the username and password
from the terminal. However, git_getpass will not echo the
username as the user types. We can fix this by using the
more generic git_prompt, which underlies git_getpass but
lets us specify an "echo" option.

Signed-off-by: Jeff King <peff@peff.net>
---
 credential.c |   15 +++++++--------
 1 files changed, 7 insertions(+), 8 deletions(-)

diff --git a/credential.c b/credential.c
index fbb7231..62d1c56 100644
--- a/credential.c
+++ b/credential.c
@@ -109,7 +109,8 @@ static void credential_describe(struct credential *c, struct strbuf *out)
 		strbuf_addf(out, "/%s", c->path);
 }
 
-static char *credential_ask_one(const char *what, struct credential *c)
+static char *credential_ask_one(const char *what, struct credential *c,
+				int flags)
 {
 	struct strbuf desc = STRBUF_INIT;
 	struct strbuf prompt = STRBUF_INIT;
@@ -121,11 +122,7 @@ static void credential_describe(struct credential *c, struct strbuf *out)
 	else
 		strbuf_addf(&prompt, "%s: ", what);
 
-	/* FIXME: for usernames, we should do something less magical that
-	 * actually echoes the characters. However, we need to read from
-	 * /dev/tty and not stdio, which is not portable (but getpass will do
-	 * it for us). http.c uses the same workaround. */
-	r = git_getpass(prompt.buf);
+	r = git_prompt(prompt.buf, flags);
 
 	strbuf_release(&desc);
 	strbuf_release(&prompt);
@@ -135,9 +132,11 @@ static void credential_describe(struct credential *c, struct strbuf *out)
 static void credential_getpass(struct credential *c)
 {
 	if (!c->username)
-		c->username = credential_ask_one("Username", c);
+		c->username = credential_ask_one("Username", c,
+						 PROMPT_ASKPASS|PROMPT_ECHO);
 	if (!c->password)
-		c->password = credential_ask_one("Password", c);
+		c->password = credential_ask_one("Password", c,
+						 PROMPT_ASKPASS);
 }
 
 int credential_read(struct credential *c, FILE *fp)
-- 
1.7.8.rc2.40.gaf387

[PATCHv2 8/9] Makefile: linux has /dev/tty

[Jeff King]

Therefore we can turn on our custom prompt function instead
of relying on getpass.

Signed-off-by: Jeff King <peff@peff.net>
---
 Makefile |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/Makefile b/Makefile
index 4ef6ba5..198fc9b 100644
--- a/Makefile
+++ b/Makefile
@@ -841,6 +841,7 @@ ifeq ($(uname_S),Linux)
 	NO_STRLCPY = YesPlease
 	NO_MKSTEMPS = YesPlease
 	HAVE_PATHS_H = YesPlease
+	HAVE_DEV_TTY = YesPlease
 endif
 ifeq ($(uname_S),GNU/kFreeBSD)
 	NO_STRLCPY = YesPlease
-- 
1.7.8.rc2.40.gaf387

[PATCHv2 9/9] Makefile: OS X has /dev/tty

[Jeff King]

We can use our enhanced getpass(). Tested by me.

Signed-off-by: Jeff King <peff@peff.net>
---
 Makefile |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/Makefile b/Makefile
index 198fc9b..1b3f5f0 100644
--- a/Makefile
+++ b/Makefile
@@ -902,6 +902,7 @@ ifeq ($(uname_S),Darwin)
 	endif
 	NO_MEMMEM = YesPlease
 	USE_ST_TIMESPEC = YesPlease
+	HAVE_DEV_TTY = YesPlease
 endif
 ifeq ($(uname_S),SunOS)
 	NEEDS_SOCKET = YesPlease
-- 
1.7.8.rc2.40.gaf387

[PATCH 1/2] Makefile: Windows lacks /dev/tty

[Johannes Sixt]

Signed-off-by: Johannes Sixt <j6t@kdbg.org>
---
These two patches go on top of jk/credentials.

 Makefile |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/Makefile b/Makefile
index 2c506b3..5b7f6a8 100644
--- a/Makefile
+++ b/Makefile
@@ -1139,6 +1139,7 @@ ifeq ($(uname_S),Windows)
 	NO_CURL = YesPlease
 	NO_PYTHON = YesPlease
 	BLK_SHA1 = YesPlease
+	NO_DEV_TTY = YesPlease
 	NO_POSIX_GOODIES = UnfortunatelyYes
 	NATIVE_CRLF = YesPlease
 
@@ -1232,6 +1233,7 @@ ifneq (,$(findstring MINGW,$(uname_S)))
 	ETAGS_TARGET = ETAGS
 	NO_INET_PTON = YesPlease
 	NO_INET_NTOP = YesPlease
+	NO_DEV_TTY = YesPlease
 	NO_POSIX_GOODIES = UnfortunatelyYes
 	COMPAT_CFLAGS += -D__USE_MINGW_ACCESS -DNOGDI -Icompat -Icompat/win32
 	COMPAT_CFLAGS += -DSTRIP_EXTENSION=\".exe\"
-- 
1.7.8.216.g2e426

[PATCH 2/2] Makefile: optionally exclude code that needs Unix sockets

[Johannes Sixt]

Introduce a configuration option NO_UNIX_SOCKETS to exclude code that
depends on Unix sockets and use it in MSVC and MinGW builds.

Notice that unix-socket.h was missing from LIB_H before; fix that, too.

Signed-off-by: Johannes Sixt <j6t@kdbg.org>
---
All or most of the tests introduced by the series fail on Windows.
What is the preferred way to exclude them? Mark the all with a
prerequisite? Or exit early at the beginning of the test file?

 Makefile |   13 ++++++++++---
 1 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/Makefile b/Makefile
index 5b7f6a8..77c85db 100644
--- a/Makefile
+++ b/Makefile
@@ -143,6 +143,8 @@ all::
 #
 # Define NO_IPV6 if you lack IPv6 support and getaddrinfo().
 #
+# Define NO_UNIX_SOCKETS if your system does not offer unix sockets.
+#
 # Define NO_SOCKADDR_STORAGE if your platform does not have struct
 # sockaddr_storage.
 #
@@ -430,8 +432,6 @@ PROGRAM_OBJS += show-index.o
 PROGRAM_OBJS += upload-pack.o
 PROGRAM_OBJS += http-backend.o
 PROGRAM_OBJS += sh-i18n--envsubst.o
-PROGRAM_OBJS += credential-cache.o
-PROGRAM_OBJS += credential-cache--daemon.o
 PROGRAM_OBJS += credential-store.o
 
 PROGRAMS += $(patsubst %.o,git-%$X,$(PROGRAM_OBJS))
@@ -709,7 +709,6 @@ LIB_OBJS += transport-helper.o
 LIB_OBJS += tree-diff.o
 LIB_OBJS += tree.o
 LIB_OBJS += tree-walk.o
-LIB_OBJS += unix-socket.o
 LIB_OBJS += unpack-trees.o
 LIB_OBJS += url.o
 LIB_OBJS += usage.o
@@ -1112,6 +1111,7 @@ ifeq ($(uname_S),Windows)
 	NO_SYS_POLL_H = YesPlease
 	NO_SYMLINK_HEAD = YesPlease
 	NO_IPV6 = YesPlease
+	NO_UNIX_SOCKETS = YesPlease
 	NO_SETENV = YesPlease
 	NO_UNSETENV = YesPlease
 	NO_STRCASESTR = YesPlease
@@ -1206,6 +1206,7 @@ ifneq (,$(findstring MINGW,$(uname_S)))
 	NO_LIBGEN_H = YesPlease
 	NO_SYS_POLL_H = YesPlease
 	NO_SYMLINK_HEAD = YesPlease
+	NO_UNIX_SOCKETS = YesPlease
 	NO_SETENV = YesPlease
 	NO_UNSETENV = YesPlease
 	NO_STRCASESTR = YesPlease
@@ -1584,6 +1585,12 @@ ifdef NO_INET_PTON
 	LIB_OBJS += compat/inet_pton.o
 	BASIC_CFLAGS += -DNO_INET_PTON
 endif
+ifndef NO_UNIX_SOCKETS
+	LIB_OBJS += unix-socket.o
+	LIB_H += unix-socket.h
+	PROGRAM_OBJS += credential-cache.o
+	PROGRAM_OBJS += credential-cache--daemon.o
+endif
 
 ifdef NO_ICONV
 	BASIC_CFLAGS += -DNO_ICONV
-- 
1.7.8.216.g2e426

Re: [PATCH 2/2] Makefile: optionally exclude code that needs Unix sockets

[Jeff King]

On Mon, Dec 12, 2011 at 10:12:56PM +0100, Johannes Sixt wrote:

> Introduce a configuration option NO_UNIX_SOCKETS to exclude code that
> depends on Unix sockets and use it in MSVC and MinGW builds.

Makes sense, thanks.

> Notice that unix-socket.h was missing from LIB_H before; fix that, too.

Oops, thanks.

> All or most of the tests introduced by the series fail on Windows.
> What is the preferred way to exclude them? Mark the all with a
> prerequisite? Or exit early at the beginning of the test file?

The cache daemon is the only thing that uses sockets. I would suggest
just exiting early from its script (patch below).

The rest of the tests should pass under Windows. If they don't, then
they should be fixed (I'm happy to work on that, with the limitation
that I don't actually have a Windows box, and if at all possible I'd
like to keep it that way).

In theory we should also disable the documentation for credential-cache.
But that means surgery not only to Documentation/Makefile, but figuring
out how to pass the flags down to the actual asciidoc process (since
gitcredentials(7) mentions it in the text). Certainly possible, but I
don't know if it's worth the effort or not.

---
diff --git a/Makefile b/Makefile
index e3ee884..6e7e190 100644
--- a/Makefile
+++ b/Makefile
@@ -2220,6 +2220,7 @@ ifdef GIT_TEST_CMP_USE_COPIED_CONTEXT
 	@echo GIT_TEST_CMP_USE_COPIED_CONTEXT=YesPlease >>$@
 endif
 	@echo GETTEXT_POISON=\''$(subst ','\'',$(subst ','\'',$(GETTEXT_POISON)))'\' >>$@
+	@echo NO_UNIX_SOCKETS=\''$(subst ','\'',$(subst ','\'',$(NO_UNIX_SOCKETS)))'\' >>$@
 
 ### Detect Tck/Tk interpreter path changes
 ifndef NO_TCLTK
diff --git a/t/t0301-credential-cache.sh b/t/t0301-credential-cache.sh
index 3a65f99..82c8411 100755
--- a/t/t0301-credential-cache.sh
+++ b/t/t0301-credential-cache.sh
@@ -4,6 +4,11 @@ test_description='credential-cache tests'
 . ./test-lib.sh
 . "$TEST_DIRECTORY"/lib-credential.sh
 
+test -z "$NO_UNIX_SOCKETS" || {
+	skip_all='skipping credential-cache tests, unix sockets not available'
+	test_done
+}
+
 # don't leave a stale daemon running
 trap 'code=$?; git credential-cache exit; (exit $code); die' EXIT
 

Re: [PATCH 2/2] Makefile: optionally exclude code that needs Unix sockets

[Junio C Hamano]

Jeff King <peff@peff.net> writes:

> In theory we should also disable the documentation for credential-cache.
> But that means surgery not only to Documentation/Makefile, but figuring
> out how to pass the flags down to the actual asciidoc process (since
> gitcredentials(7) mentions it in the text). Certainly possible, but I
> don't know if it's worth the effort or not.

I do not think it matters that much. We've been shipping documentation for
stuff like remote archiver and daemon without conditional compilation, no?

Re: [PATCH 2/2] Makefile: optionally exclude code that needs Unix sockets

[Jeff King]

On Mon, Dec 12, 2011 at 03:31:44PM -0800, Junio C Hamano wrote:

> > In theory we should also disable the documentation for credential-cache.
> > But that means surgery not only to Documentation/Makefile, but figuring
> > out how to pass the flags down to the actual asciidoc process (since
> > gitcredentials(7) mentions it in the text). Certainly possible, but I
> > don't know if it's worth the effort or not.
> 
> I do not think it matters that much. We've been shipping documentation for
> stuff like remote archiver and daemon without conditional compilation, no?

True. Let's not worry about it, then.

> I'll queue a single patch that is a squash between 2/2 and Peff's test
> updates between "credentials: add "cache" helper" and "strbuf: add
> strbuf_add*_urlencode" in the series.

That's perfect. Thanks.

-Peff

Re: [PATCH 2/2] Makefile: optionally exclude code that needs Unix sockets

[Junio C Hamano]

I'll queue a single patch that is a squash between 2/2 and Peff's test
updates between "credentials: add "cache" helper" and "strbuf: add
strbuf_add*_urlencode" in the series.

Thanks.

Re: [PATCH 2/2] Makefile: optionally exclude code that needs Unix sockets

[Johannes Sixt]

Am 13.12.2011 01:45, schrieb Junio C Hamano:
> I'll queue a single patch that is a squash between 2/2 and Peff's test
> updates between "credentials: add "cache" helper" and "strbuf: add
> strbuf_add*_urlencode" in the series.

Thanks. The resulting series builds fine on Windows and passes/skips the
new tests in the expected manner.

-- Hannes

Re: [PATCH 2/2] Makefile: optionally exclude code that needs Unix sockets

[Junio C Hamano]

Johannes Sixt <j6t@kdbg.org> writes:

> Am 13.12.2011 01:45, schrieb Junio C Hamano:
>> I'll queue a single patch that is a squash between 2/2 and Peff's test
>> updates between "credentials: add "cache" helper" and "strbuf: add
>> strbuf_add*_urlencode" in the series.
>
> Thanks. The resulting series builds fine on Windows and passes/skips the
> new tests in the expected manner.

Thanks. Let's advance the topic forward then.

Re: [PATCH 1/2] Makefile: Windows lacks /dev/tty

[Jeff King]

On Mon, Dec 12, 2011 at 10:10:03PM +0100, Johannes Sixt wrote:

> diff --git a/Makefile b/Makefile
> index 2c506b3..5b7f6a8 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -1139,6 +1139,7 @@ ifeq ($(uname_S),Windows)
>  	NO_CURL = YesPlease
>  	NO_PYTHON = YesPlease
>  	BLK_SHA1 = YesPlease
> +	NO_DEV_TTY = YesPlease
>  	NO_POSIX_GOODIES = UnfortunatelyYes
>  	NATIVE_CRLF = YesPlease
>  
> @@ -1232,6 +1233,7 @@ ifneq (,$(findstring MINGW,$(uname_S)))
>  	ETAGS_TARGET = ETAGS
>  	NO_INET_PTON = YesPlease
>  	NO_INET_NTOP = YesPlease
> +	NO_DEV_TTY = YesPlease
>  	NO_POSIX_GOODIES = UnfortunatelyYes
>  	COMPAT_CFLAGS += -D__USE_MINGW_ACCESS -DNOGDI -Icompat -Icompat/win32
>  	COMPAT_CFLAGS += -DSTRIP_EXTENSION=\".exe\"

Unless I've bungled something, these should be no-ops, shouldn't they?
The most recent version of the prompt series has platforms opting into
the replacement with HAVE_DEV_TTY.

-Peff

Re: [PATCH 1/2] Makefile: Windows lacks /dev/tty

[Johannes Sixt]

Am 12.12.2011 22:18, schrieb Jeff King:
> The most recent version of the prompt series has platforms opting into
> the replacement with HAVE_DEV_TTY.

I see. Obviously, I've tested an earlier iteration. This patch can be
dropped then.

-- Hannes

[PATCH 1/1] contrib: add credential helper for OS X Keychain

[Jeff King]

On Sat, Dec 10, 2011 at 05:28:27AM -0500, Jeff King wrote:

> Here's the latest re-roll of the credential helpers series. I think this
> one is probably ready to go to 'next'.
> 
> It's rebased on the latest tip of 'master' (applying it to an older
> commit will get you a minor textual conflict in strbuf.c). It
> incorporates the erase-safety we discussed, fixes a few commit message
> typos, and tweaks the test scripts to make testing the external OS X
> helper a little easier.

And here is that helper.

-- >8 --
Subject: [PATCH] contrib: add credential helper for OS X Keychain

With this installed in your $PATH, you can store
git-over-http passwords in your keychain by doing:

  git config credential.helper osxkeychain

The code is based in large part on the work of Jay Soffian,
who wrote the helper originally for the initial, unpublished
version of the credential helper protocol.

This version will pass t0303 if you do:

  GIT_TEST_CREDENTIAL_HELPER=osxkeychain \
  GIT_TEST_CREDENTIAL_HELPER_SETUP="export HOME=$HOME" \
  ./t0303-credential-external.sh

The "HOME" setup is unfortunately necessary. The test
scripts set HOME to the trash directory, but this causes the
keychain API to complain.

Signed-off-by: Jeff King <peff@peff.net>
---
I tried clever workarounds for the HOME thing, like running "security
create-keychain" in the trash directory. But if I try to create the
"login" keychain, it says it's already there! So it's like we're in a
weird limbo where we both have and do not have access to the keychains.

I'm not too concerned with the hackishness of my solution, though; this
isn't even a part of the regular test scripts, but just a thing you can
do manually to test the helper from contrib.

Many thanks to Jay for the initial version; even though this version is
quite chopped-up, having somebody else provide a nice example of how to
use the SecKeychain functions made it much easier. I tried to trim the
code down to the bare essentials to glue our input into the SecKeychain
API, and to show good practices for other helpers to follow.

I dropped the python version, as it is redundant and I didn't feel like
porting it to the new interface. It could be added on top if somebody
feels like converting it as an exercise. :)

 contrib/credential/osxkeychain/.gitignore          |    1 +
 contrib/credential/osxkeychain/Makefile            |   14 ++
 .../osxkeychain/git-credential-osxkeychain.c       |  173 ++++++++++++++++++++
 3 files changed, 188 insertions(+), 0 deletions(-)
 create mode 100644 contrib/credential/osxkeychain/.gitignore
 create mode 100644 contrib/credential/osxkeychain/Makefile
 create mode 100644 contrib/credential/osxkeychain/git-credential-osxkeychain.c

diff --git a/contrib/credential/osxkeychain/.gitignore b/contrib/credential/osxkeychain/.gitignore
new file mode 100644
index 0000000..6c5b702
--- /dev/null
+++ b/contrib/credential/osxkeychain/.gitignore
@@ -0,0 +1 @@
+git-credential-osxkeychain
diff --git a/contrib/credential/osxkeychain/Makefile b/contrib/credential/osxkeychain/Makefile
new file mode 100644
index 0000000..75c07f8
--- /dev/null
+++ b/contrib/credential/osxkeychain/Makefile
@@ -0,0 +1,14 @@
+all:: git-credential-osxkeychain
+
+CC = gcc
+RM = rm -f
+CFLAGS = -g -Wall
+
+git-credential-osxkeychain: git-credential-osxkeychain.o
+	$(CC) -o $@ $< -Wl,-framework -Wl,Security
+
+git-credential-osxkeychain.o: git-credential-osxkeychain.c
+	$(CC) -c $(CFLAGS) $<
+
+clean:
+	$(RM) git-credential-osxkeychain git-credential-osxkeychain.o
diff --git a/contrib/credential/osxkeychain/git-credential-osxkeychain.c b/contrib/credential/osxkeychain/git-credential-osxkeychain.c
new file mode 100644
index 0000000..6beed12
--- /dev/null
+++ b/contrib/credential/osxkeychain/git-credential-osxkeychain.c
@@ -0,0 +1,173 @@
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <Security/Security.h>
+
+static SecProtocolType protocol;
+static char *host;
+static char *path;
+static char *username;
+static char *password;
+static UInt16 port;
+
+static void die(const char *err, ...)
+{
+	char msg[4096];
+	va_list params;
+	va_start(params, err);
+	vsnprintf(msg, sizeof(msg), err, params);
+	fprintf(stderr, "%s\n", msg);
+	va_end(params);
+	exit(1);
+}
+
+static void *xstrdup(const char *s1)
+{
+	void *ret = strdup(s1);
+	if (!ret)
+		die("Out of memory");
+	return ret;
+}
+
+#define KEYCHAIN_ITEM(x) (x ? strlen(x) : 0), x
+#define KEYCHAIN_ARGS \
+	NULL, /* default keychain */ \
+	KEYCHAIN_ITEM(host), \
+	0, NULL, /* account domain */ \
+	KEYCHAIN_ITEM(username), \
+	KEYCHAIN_ITEM(path), \
+	port, \
+	protocol, \
+	kSecAuthenticationTypeDefault
+
+static void write_item(const char *what, const char *buf, int len)
+{
+	printf("%s=", what);
+	fwrite(buf, 1, len, stdout);
+	putchar('\n');
+}
+
+static void find_username_in_item(SecKeychainItemRef item)
+{
+	SecKeychainAttributeList list;
+	SecKeychainAttribute attr;
+
+	list.count = 1;
+	list.attr = &attr;
+	attr.tag = kSecAccountItemAttr;
+
+	if (SecKeychainItemCopyContent(item, NULL, &list, NULL, NULL))
+		return;
+
+	write_item("username", attr.data, attr.length);
+	SecKeychainItemFreeContent(&list, NULL);
+}
+
+static void find_internet_password(void)
+{
+	void *buf;
+	UInt32 len;
+	SecKeychainItemRef item;
+
+	if (SecKeychainFindInternetPassword(KEYCHAIN_ARGS, &len, &buf, &item))
+		return;
+
+	write_item("password", buf, len);
+	if (!username)
+		find_username_in_item(item);
+
+	SecKeychainItemFreeContent(NULL, buf);
+}
+
+static void delete_internet_password(void)
+{
+	SecKeychainItemRef item;
+
+	/*
+	 * Require at least a protocol and host for removal, which is what git
+	 * will give us; if you want to do something more fancy, use the
+	 * Keychain manager.
+	 */
+	if (!protocol || !host)
+		return;
+
+	if (SecKeychainFindInternetPassword(KEYCHAIN_ARGS, 0, NULL, &item))
+		return;
+
+	SecKeychainItemDelete(item);
+}
+
+static void add_internet_password(void)
+{
+	/* Only store complete credentials */
+	if (!protocol || !host || !username || !password)
+		return;
+
+	if (SecKeychainAddInternetPassword(
+	      KEYCHAIN_ARGS,
+	      KEYCHAIN_ITEM(password),
+	      NULL))
+		return;
+}
+
+static void read_credential(void)
+{
+	char buf[1024];
+
+	while (fgets(buf, sizeof(buf), stdin)) {
+		char *v;
+
+		if (!strcmp(buf, "\n"))
+			break;
+		buf[strlen(buf)-1] = '\0';
+
+		v = strchr(buf, '=');
+		if (!v)
+			die("bad input: %s", buf);
+		*v++ = '\0';
+
+		if (!strcmp(buf, "protocol")) {
+			if (!strcmp(v, "https"))
+				protocol = kSecProtocolTypeHTTPS;
+			else if (!strcmp(v, "http"))
+				protocol = kSecProtocolTypeHTTP;
+			else /* we don't yet handle other protocols */
+				exit(0);
+		}
+		else if (!strcmp(buf, "host")) {
+			char *colon = strchr(v, ':');
+			if (colon) {
+				*colon++ = '\0';
+				port = atoi(colon);
+			}
+			host = xstrdup(v);
+		}
+		else if (!strcmp(buf, "path"))
+			path = xstrdup(v);
+		else if (!strcmp(buf, "username"))
+			username = xstrdup(v);
+		else if (!strcmp(buf, "password"))
+			password = xstrdup(v);
+	}
+}
+
+int main(int argc, const char **argv)
+{
+	const char *usage =
+		"Usage: git credential-osxkeychain <get|store|erase>";
+
+	if (!argv[1])
+		die(usage);
+
+	read_credential();
+
+	if (!strcmp(argv[1], "get"))
+		find_internet_password();
+	else if (!strcmp(argv[1], "store"))
+		add_internet_password();
+	else if (!strcmp(argv[1], "erase"))
+		delete_internet_password();
+	/* otherwise, ignore unknown action */
+
+	return 0;
+}
-- 
1.7.8.rc2.40.gaf387