From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on dcvr.yhbt.net X-Spam-Level: X-Spam-ASN: AS31976 209.132.180.0/23 X-Spam-Status: No, score=-5.2 required=3.0 tests=AWL,BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD shortcircuit=no autolearn=ham autolearn_force=no version=3.4.0 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by dcvr.yhbt.net (Postfix) with ESMTP id 8FF05203C1 for ; Thu, 14 Jul 2016 21:50:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751380AbcGNVt4 (ORCPT ); Thu, 14 Jul 2016 17:49:56 -0400 Received: from mail-pa0-f44.google.com ([209.85.220.44]:34461 "EHLO mail-pa0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751348AbcGNVtz (ORCPT ); Thu, 14 Jul 2016 17:49:55 -0400 Received: by mail-pa0-f44.google.com with SMTP id fi15so32219583pac.1 for ; Thu, 14 Jul 2016 14:49:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20120113; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=OPlGDdB/EJw+HcGDSwRY8u6HstYeVUiUx3Fnl1sVIwY=; b=FXhuZCInhpCqi5pxprEGeWzekULiUvFJPgFTBzIyjP2VT2lGKjYLzMc2nuGNudcC7a HN8GcgilXN+1z7Vmer+fTjITWuaHXoO47u5DD9q6ZZCLEPzgr+zFgisy22efhaG58EnB s/bi+H/yctouIPwcHroewG1lUWITcyGRpI2OOZ4gsh+lgM9t0aqFdDRxL/gR6ck1FUoq No23r7KqmvD74OoRu2OeOsE4LzVxgFQj0WaUqK1wN/cJa3oiNmNLKRnBenochu2Lazsg AhzxhBrUC7HlB5xs8a6O0ap5cde0RhEyrApr8PCSNr9Onu9/BSXD8ZnZdTbozqFH0Vwg I+sw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=OPlGDdB/EJw+HcGDSwRY8u6HstYeVUiUx3Fnl1sVIwY=; b=DTQW6GFyg/Z0TBX9aRkBKhAWJ25B8YBMW7N23H4YttnmOfG5ctKJmTn7qs0J4Sqi0U 0mP2ESedO1kjqpMlR8jpA01DuBXrk1VyiqxyuDifoSMGU2iJykhF+1964fu+6j7m3bNL x8/lMGK7msRsH2pxp7BnjPEc422jiSYQ4OZwVatGCCiRQZgihxY+PSjixVEGm8Yh10+s Q3teu2Z2k4XjxokqnvJaoc6lPcr4ncSDiMPUvjb3WTVDyAUKoIv9+pFVFi3bdeejd4BD vJtKOKqBmGrWPX2eS7+dXUjNQaJaj+VKx0rsEL3Kk6LZKR8j+oEqF8IFmFgwyPEoO5Dk WgUw== X-Gm-Message-State: ALyK8tIpzgghYnMIB+Jqwr3AUzr72EPG1mJfd6Of8xtU2F4RwI1Ux1eX7oe/xyNzo56TA3ib X-Received: by 10.66.11.234 with SMTP id t10mr26077875pab.66.1468532993809; Thu, 14 Jul 2016 14:49:53 -0700 (PDT) Received: from localhost ([2620:0:1000:5b10:c041:4809:7eab:7652]) by smtp.gmail.com with ESMTPSA id z1sm6963510pab.19.2016.07.14.14.49.53 (version=TLS1_2 cipher=AES128-SHA bits=128/128); Thu, 14 Jul 2016 14:49:53 -0700 (PDT) From: Stefan Beller To: git@vger.kernel.org, gitster@pobox.com Cc: dwwang@google.com, e@80x24.org, peff@peff.net, dennis@kaarsemaker.net, jrnieder@gmail.com, Stefan Beller Subject: [PATCH 1/4] push options: {pre,post}-receive hook learns about push options Date: Thu, 14 Jul 2016 14:49:45 -0700 Message-Id: <20160714214948.27432-2-sbeller@google.com> X-Mailer: git-send-email 2.9.0.247.gf748855.dirty In-Reply-To: <20160714214948.27432-1-sbeller@google.com> References: <20160714214948.27432-1-sbeller@google.com> Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org The environment variable GIT_PUSH_OPTION_COUNT is set to the number of push options sent, and GIT_PUSH_OPTION_{0,1,..} is set to the transmitted option. The code is not executed as the push options are set to NULL, nor is the new capability advertised. There was some discussion back and forth how to present these push options to the user as there are some ways to do it: Keep all options in one environment variable ============================================ + easiest way to implement in Git - This would make things hard to parse correctly in the hook. Put the options in files instead, filenames are in GIT_PUSH_OPTION_FILES ====================================== + After a discussion about environment variables and shells, we may not want to put user data into an environment variable (see [1] for example). + We could transmit binaries, i.e. we're not bound to C strings as we are when using environment variables to the user. + Maybe easier to parse than constructing environment variable names GIT_PUSH_OPTION_{0,1,..} yourself - cleanup of the temporary files is hard to do reliably - we have race conditions with multiple clients pushing, hence we'd need to use mkstemp. That's not too bad, but still. Use environment variables, but restrict to key/value pairs ========================================================== (When the user pushes a push option `foo=bar`, we'd GIT_PUSH_OPTION_foo=bar) + very easy to parse for a simple model of push options - it's not sufficient for more elaborate models, e.g. it doesn't allow doubles (e.g. cc=reviewer@email) Present the options in different environment variables ====================================================== (This is implemented) * harder to parse as a user, but we have a sample hook for that. - doesn't allow binary files + allows the same option twice, i.e. is not restrictive about options, except for binary files. + doesn't clutter a remote directory with (possibly stale) temporary files As we first want to focus on getting simple strings to work reliably, we go with the last option for now. If we want to do transmission of binaries later, we can just attach a 'side-channel', e.g. "any push option that contains a '\0' is put into a file instead of the environment variable and we'd have new GIT_PUSH_OPTION_FILES, GIT_PUSH_OPTION_FILENAME_{0,1,..} environment variables". We limit the push options for now * to not exceed an arbitrary count, and * to not exceed an arbitrary size. This serves two purposes: * DoS protection (i.e. one connection can add no more than 32kB now) * We need to figure out how to handle large (>64kB). Jeff wrote: > Yes, but people are also happy when they can use a flexible and > standardized tool to do a thing. I'd be more frustrated when I found out > that Git's data-pushing protocol has arbitrary limitations (like, say, I > can't push a data item larger than a single 64K pkt-line), which would > easily just work with something like HTTP POSTs. So to keep a way open in the future to deal with large pay loads, the size is restricted for now. [1] 'Shellshock' https://lwn.net/Articles/614218/ Signed-off-by: Stefan Beller --- Documentation/githooks.txt | 18 ++++++++++++++ builtin/receive-pack.c | 47 +++++++++++++++++++++++++++---------- templates/hooks--pre-receive.sample | 24 +++++++++++++++++++ 3 files changed, 76 insertions(+), 13 deletions(-) create mode 100644 templates/hooks--pre-receive.sample diff --git a/Documentation/githooks.txt b/Documentation/githooks.txt index d82e912..9565dc3 100644 --- a/Documentation/githooks.txt +++ b/Documentation/githooks.txt @@ -247,6 +247,15 @@ Both standard output and standard error output are forwarded to 'git send-pack' on the other end, so you can simply `echo` messages for the user. +The number of push options given on the command line of +`git push --push-option=...` can be read from the environment +variable `GIT_PUSH_OPTION_COUNT`, and the options themselves are +found in `GIT_PUSH_OPTION_0`, `GIT_PUSH_OPTION_1`,... +If it is negotiated to not use the push options phase, the +environment variables will not be set. If the client selects +to use push options, but doesn't transmit any, the count variable +will be set to zero, `GIT_PUSH_OPTION_COUNT=0`. + [[update]] update ~~~~~~ @@ -322,6 +331,15 @@ a sample script `post-receive-email` provided in the `contrib/hooks` directory in Git distribution, which implements sending commit emails. +The number of push options given on the command line of +`git push --push-option=...` can be read from the environment +variable `GIT_PUSH_OPTION_COUNT`, and the options themselves are +found in `GIT_PUSH_OPTION_0`, `GIT_PUSH_OPTION_1`,... +If it is negotiated to not use the push options phase, the +environment variables will not be set. If the client selects +to use push options, but doesn't transmit any, the count variable +will be set to zero, `GIT_PUSH_OPTION_COUNT=0`. + [[post-update]] post-update ~~~~~~~~~~~ diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c index 15c323a..6cdd2c6 100644 --- a/builtin/receive-pack.c +++ b/builtin/receive-pack.c @@ -550,8 +550,16 @@ static void prepare_push_cert_sha1(struct child_process *proc) } } +struct receive_hook_feed_state { + struct command *cmd; + int skip_broken; + struct strbuf buf; + const struct string_list *push_options; +}; + typedef int (*feed_fn)(void *, const char **, size_t *); -static int run_and_feed_hook(const char *hook_name, feed_fn feed, void *feed_state) +static int run_and_feed_hook(const char *hook_name, feed_fn feed, + struct receive_hook_feed_state *feed_state) { struct child_process proc = CHILD_PROCESS_INIT; struct async muxer; @@ -567,6 +575,16 @@ static int run_and_feed_hook(const char *hook_name, feed_fn feed, void *feed_sta proc.argv = argv; proc.in = -1; proc.stdout_to_stderr = 1; + if (feed_state->push_options) { + int i; + for (i = 0; i < feed_state->push_options->nr; i++) + argv_array_pushf(&proc.env_array, + "GIT_PUSH_OPTION_%d=%s", i, + feed_state->push_options->items[i].string); + argv_array_pushf(&proc.env_array, "GIT_PUSH_OPTION_COUNT=%d", + feed_state->push_options->nr); + } else + argv_array_pushf(&proc.env_array, "GIT_PUSH_OPTION_COUNT"); if (use_sideband) { memset(&muxer, 0, sizeof(muxer)); @@ -606,12 +624,6 @@ static int run_and_feed_hook(const char *hook_name, feed_fn feed, void *feed_sta return finish_command(&proc); } -struct receive_hook_feed_state { - struct command *cmd; - int skip_broken; - struct strbuf buf; -}; - static int feed_receive_hook(void *state_, const char **bufp, size_t *sizep) { struct receive_hook_feed_state *state = state_; @@ -634,8 +646,10 @@ static int feed_receive_hook(void *state_, const char **bufp, size_t *sizep) return 0; } -static int run_receive_hook(struct command *commands, const char *hook_name, - int skip_broken) +static int run_receive_hook(struct command *commands, + const char *hook_name, + int skip_broken, + const struct string_list *push_options) { struct receive_hook_feed_state state; int status; @@ -646,6 +660,7 @@ static int run_receive_hook(struct command *commands, const char *hook_name, if (feed_receive_hook(&state, NULL, NULL)) return 0; state.cmd = commands; + state.push_options = push_options; status = run_and_feed_hook(hook_name, feed_receive_hook, &state); strbuf_release(&state.buf); return status; @@ -1316,7 +1331,8 @@ cleanup: static void execute_commands(struct command *commands, const char *unpacker_error, - struct shallow_info *si) + struct shallow_info *si, + const struct string_list *push_options) { struct command *cmd; unsigned char sha1[20]; @@ -1335,7 +1351,7 @@ static void execute_commands(struct command *commands, reject_updates_to_hidden(commands); - if (run_receive_hook(commands, "pre-receive", 0)) { + if (run_receive_hook(commands, "pre-receive", 0, push_options)) { for (cmd = commands; cmd; cmd = cmd->next) { if (!cmd->error_string) cmd->error_string = "pre-receive hook declined"; @@ -1756,6 +1772,7 @@ int cmd_receive_pack(int argc, const char **argv, const char *prefix) if ((commands = read_head_info(&shallow)) != NULL) { const char *unpack_status = NULL; + struct string_list push_options = STRING_LIST_INIT_DUP; prepare_shallow_info(&si, &shallow); if (!si.nr_ours && !si.nr_theirs) @@ -1764,13 +1781,17 @@ int cmd_receive_pack(int argc, const char **argv, const char *prefix) unpack_status = unpack_with_sideband(&si); update_shallow_info(commands, &si, &ref); } - execute_commands(commands, unpack_status, &si); + execute_commands(commands, unpack_status, &si, + &push_options); if (pack_lockfile) unlink_or_warn(pack_lockfile); if (report_status) report(commands, unpack_status); - run_receive_hook(commands, "post-receive", 1); + run_receive_hook(commands, "post-receive", 1, + &push_options); run_update_post_hook(commands); + if (push_options.nr) + string_list_clear(&push_options, 0); if (auto_gc) { const char *argv_gc_auto[] = { "gc", "--auto", "--quiet", NULL, diff --git a/templates/hooks--pre-receive.sample b/templates/hooks--pre-receive.sample new file mode 100644 index 0000000..a1fd29e --- /dev/null +++ b/templates/hooks--pre-receive.sample @@ -0,0 +1,24 @@ +#!/bin/sh +# +# An example hook script to make use of push options. +# The example simply echoes all push options that start with 'echoback=' +# and rejects all pushes when the "reject" push option is used. +# +# To enable this hook, rename this file to "pre-receive". + +if test -n "$GIT_PUSH_OPTION_COUNT" +then + i=0 + while test "$i" -lt "$GIT_PUSH_OPTION_COUNT" + do + eval "value=\$GIT_PUSH_OPTION_$i" + case "$value" in + echoback=*) + echo "echo from the pre-receive-hook: ${value#*=}" >&2 + ;; + reject) + exit 1 + esac + i=$((i + 1)) + done +fi -- 2.9.0.247.gf748855.dirty