* [LTP] [PATCH] new testcase: kmsg01
@ 2013-06-11 13:47 Jan Stancek
2013-06-17 15:13 ` chrubis
0 siblings, 1 reply; 3+ messages in thread
From: Jan Stancek @ 2013-06-11 13:47 UTC (permalink / raw)
To: ltp-list
Test /dev/kmsg based on kernel doc: Documentation/ABI/testing/dev-kmsg
- read() blocks
- non-blocking read() fails with EAGAIN
- partial read fails (buffer smaller than message)
- can write to /dev/kmsg and message seqno grows
- first read() after open() returns same message
- if messages get overwritten, read() returns -EPIPE
- device supports SEEK_SET, SEEK_END, SEEK_DATA
Signed-off-by: Jan Stancek <jstancek@redhat.com>
---
runtest/logging | 1 +
testcases/kernel/logging/.gitignore | 1 +
testcases/kernel/logging/Makefile | 22 ++
testcases/kernel/logging/kmsg/Makefile | 22 ++
testcases/kernel/logging/kmsg/kmsg01.c | 513 ++++++++++++++++++++++++++++++++
5 files changed, 559 insertions(+), 0 deletions(-)
create mode 100644 runtest/logging
create mode 100644 testcases/kernel/logging/.gitignore
create mode 100644 testcases/kernel/logging/Makefile
create mode 100644 testcases/kernel/logging/kmsg/Makefile
create mode 100644 testcases/kernel/logging/kmsg/kmsg01.c
diff --git a/runtest/logging b/runtest/logging
new file mode 100644
index 0000000..47a667e
--- /dev/null
+++ b/runtest/logging
@@ -0,0 +1 @@
+kmsg01 kmsg01
diff --git a/testcases/kernel/logging/.gitignore b/testcases/kernel/logging/.gitignore
new file mode 100644
index 0000000..4236df0
--- /dev/null
+++ b/testcases/kernel/logging/.gitignore
@@ -0,0 +1 @@
+/kmsg/kmsg01
diff --git a/testcases/kernel/logging/Makefile b/testcases/kernel/logging/Makefile
new file mode 100644
index 0000000..bd32f70
--- /dev/null
+++ b/testcases/kernel/logging/Makefile
@@ -0,0 +1,22 @@
+#
+# Copyright (C) 2013 Linux Test Project
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
+# the GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+#
+
+top_srcdir ?= ../../..
+
+include $(top_srcdir)/include/mk/env_pre.mk
+include $(top_srcdir)/include/mk/generic_trunk_target.mk
diff --git a/testcases/kernel/logging/kmsg/Makefile b/testcases/kernel/logging/kmsg/Makefile
new file mode 100644
index 0000000..67b29d6
--- /dev/null
+++ b/testcases/kernel/logging/kmsg/Makefile
@@ -0,0 +1,22 @@
+#
+# Copyright (C) 2013 Linux Test Project
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
+# the GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+#
+
+top_srcdir ?= ../../../..
+
+include $(top_srcdir)/include/mk/testcases.mk
+include $(top_srcdir)/include/mk/generic_leaf_target.mk
diff --git a/testcases/kernel/logging/kmsg/kmsg01.c b/testcases/kernel/logging/kmsg/kmsg01.c
new file mode 100644
index 0000000..c4082c7
--- /dev/null
+++ b/testcases/kernel/logging/kmsg/kmsg01.c
@@ -0,0 +1,513 @@
+/*
+ * Copyright (C) 2013 Linux Test Project
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of version 2 of the GNU General Public
+ * License as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it would be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * Further, this software is distributed without any warranty that it
+ * is free of the rightful claim of any third person regarding
+ * infringement or the like. Any license provided herein, whether
+ * implied or otherwise, applies only to this software file. Patent
+ * licenses, if any, provided herein do not apply to combinations of
+ * this program with other software, or any other product whatsoever.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+/*
+ * Test /dev/kmsg based on kernel doc: Documentation/ABI/testing/dev-kmsg
+ * - read() blocks
+ * - non-blocking read() fails with EAGAIN
+ * - partial read fails (buffer smaller than message)
+ * - can write to /dev/kmsg and message seqno grows
+ * - first read() after open() returns same message
+ * - if messages get overwritten, read() returns -EPIPE
+ * - device supports SEEK_SET, SEEK_END, SEEK_DATA
+ */
+#define _GNU_SOURCE
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/syscall.h>
+#include <sys/wait.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include "config.h"
+#include "test.h"
+#include "usctest.h"
+#include "safe_macros.h"
+#include "linux_syscall_numbers.h"
+
+#define MSG_PREFIX "LTP KMSG "
+#define MAX_MSGSIZE 4096
+#define NUM_READ_MSGS 3
+#define NUM_OVERWRITE_MSGS 1024
+#define READ_TIMEOUT 5
+
+char *TCID = "kmsg01";
+static void setup(void);
+static void cleanup(void);
+
+/*
+ * inject_msg - write message to /dev/kmsg
+ * @msg: null-terminated message to inject, should end with \n
+ *
+ * RETURNS:
+ * 0 on success
+ * -1 on failure, errno reflects write() errno
+ */
+static int inject_msg(const char *msg)
+{
+ int f;
+ f = open("/dev/kmsg", O_RDWR);
+ if (f < 0)
+ tst_brkm(TBROK | TERRNO, cleanup, "failed to open /dev/kmsg");
+ TEST(write(f, msg, strlen(msg)));
+ close(f);
+ errno = TEST_ERRNO;
+ return TEST_RETURN;
+}
+
+/*
+ * find_msg - find message in kernel ring buffer
+ * @fd: fd to use, if < 0 function opens /dev/kmsg itself
+ * @text_to_find: substring to look for in messages
+ * @buf: buf to store found message
+ * @bufsize: size of 'buf'
+ * @first: 1 - return first matching message
+ * 0 - return last matching message
+ * RETURNS:
+ * 0 on success
+ * -1 on failure
+ */
+static int find_msg(int fd, const char *text_to_find, char *buf, int bufsize,
+ int first)
+{
+ int f, msg_found = 0;
+ char *msg;
+
+ msg = SAFE_MALLOC(cleanup, bufsize);
+ if (fd < 0) {
+ f = open("/dev/kmsg", O_RDONLY | O_NONBLOCK);
+ if (f < 0)
+ tst_brkm(TBROK, cleanup, "failed to open /dev/kmsg");
+ } else {
+ f = fd;
+ }
+
+ while (1) {
+ TEST(read(f, msg, bufsize));
+ if (TEST_RETURN < 0) {
+ if (TEST_ERRNO == EAGAIN)
+ /* there are no more messages */
+ break;
+ else
+ tst_brkm(TBROK|TTERRNO, cleanup,
+ "failed to read /dev/kmsg");
+ } else if (TEST_RETURN < bufsize) {
+ /* lines from kmsg are not NULL terminated */
+ msg[TEST_RETURN] = '\0';
+ if (strstr(msg, text_to_find) != NULL) {
+ memcpy(buf, msg, TEST_RETURN+1);
+ msg_found = 1;
+ if (first)
+ break;
+ }
+ }
+ };
+ free(msg);
+ if (fd < 0)
+ close(f);
+
+ if (msg_found)
+ return 0;
+ else
+ return -1;
+}
+
+static int get_msg_fields(const char *msg, unsigned long *prio,
+ unsigned long *seqno)
+{
+ unsigned long s, p;
+ if (sscanf(msg, "%lu,%lu,", &p, &s) == 2) {
+ if (prio)
+ *prio = p;
+ if (seqno)
+ *seqno = s;
+ return 0;
+ } else {
+ return 1;
+ }
+}
+
+/*
+ * timed_read - if possible reads from fd or times out
+ * @fd: fd to read from
+ * @timeout_sec: timeout in seconds
+ *
+ * RETURNS:
+ * read bytes on successful read
+ * -1 on read() error, errno reflects read() errno
+ * -2 on timeout
+ */
+static int timed_read(int fd, int timeout_sec)
+{
+ int ret, tmp;
+ struct timeval timeout;
+ fd_set read_fds;
+
+ FD_ZERO(&read_fds);
+ FD_SET(fd, &read_fds);
+ timeout.tv_sec = timeout_sec;
+ timeout.tv_usec = 0;
+
+ ret = select(fd + 1, &read_fds, 0, 0, &timeout);
+ switch (ret) {
+ case -1:
+ tst_brkm(TBROK|TERRNO, cleanup, "select failed");
+ case 0:
+ /* select timed out */
+ return -2;
+ }
+
+ ret = read(fd, &tmp, 1);
+ return ret;
+}
+
+/*
+ * timed_read_file - reads file until it reaches end of file,
+ * read fails or times out.
+ * @fd: fd to read from
+ * @timeout_sec: timeout in seconds for every read attempt
+ *
+ * RETURNS:
+ * 0 on read reaching eof
+ * -1 on read error, errno reflects read() errno
+ * -2 on timeout
+ */
+static int timed_read_file(int fd, int timeout_sec)
+{
+ int child, status;
+ int pipefd[2];
+ char msg[MAX_MSGSIZE];
+
+ if (pipe(pipefd) != 0)
+ tst_brkm(TBROK|TERRNO, cleanup, "pipe failed");
+
+ child = fork();
+ switch (child) {
+ case -1:
+ tst_brkm(TBROK|TERRNO, cleanup, "failed to fork");
+ case 0:
+ /* child does all the reading and keeps writing to
+ * pipe to let parent know that it didn't block */
+ close(pipefd[0]);
+ do {
+ write(pipefd[1], "", 1);
+ TEST(read(fd, msg, MAX_MSGSIZE));
+ } while (TEST_RETURN > 0);
+
+ close(pipefd[1]);
+ if (TEST_RETURN == -1)
+ exit(TEST_ERRNO);
+ exit(0);
+ }
+ close(pipefd[1]);
+
+ /* parent reads pipe until it reaches eof or until read times out */
+ do {
+ TEST(timed_read(pipefd[0], timeout_sec));
+ } while (TEST_RETURN > 0);
+ close(pipefd[0]);
+
+ if (TEST_RETURN == -2)
+ /* child is blocked, kill it */
+ kill(child, SIGTERM);
+ if (waitpid(child, &status, 0) == -1)
+ tst_brkm(TBROK | TERRNO, cleanup, "waitpid");
+ if (WIFEXITED(status)) {
+ if (WEXITSTATUS(status) == 0) {
+ return 0;
+ } else {
+ errno = WEXITSTATUS(status);
+ return -1;
+ }
+ }
+ return -2;
+}
+
+static void test_read_nonblock(void)
+{
+ int fd;
+
+ tst_resm(TINFO, "TEST: nonblock read");
+ fd = open("/dev/kmsg", O_RDWR | O_NONBLOCK);
+ if (fd < 0)
+ tst_brkm(TBROK|TERRNO, cleanup, "failed to open /dev/kmsg");
+
+ TEST(timed_read_file(fd, READ_TIMEOUT));
+ if (TEST_RETURN == -1 && TEST_ERRNO == EAGAIN)
+ tst_resm(TPASS, "non-block read returned EAGAIN");
+ else
+ tst_resm(TFAIL|TTERRNO, "non-block read returned: %ld",
+ TEST_RETURN);
+ close(fd);
+}
+
+static void test_read_block(void)
+{
+ int fd;
+
+ tst_resm(TINFO, "TEST: blocking read");
+ fd = open("/dev/kmsg", O_RDWR);
+ if (fd < 0)
+ tst_brkm(TBROK|TERRNO, cleanup, "failed to open /dev/kmsg");
+
+ TEST(timed_read_file(fd, READ_TIMEOUT));
+ if (TEST_RETURN == -2)
+ tst_resm(TPASS, "read blocked");
+ else
+ tst_resm(TFAIL|TTERRNO, "read returned: %ld", TEST_RETURN);
+ close(fd);
+}
+
+static void test_partial_read(void)
+{
+ char msg[MAX_MSGSIZE];
+ int fd;
+
+ tst_resm(TINFO, "TEST: partial read");
+ fd = open("/dev/kmsg", O_RDWR);
+ if (fd < 0)
+ tst_brkm(TBROK|TERRNO, cleanup, "failed to open /dev/kmsg");
+
+ TEST(read(fd, msg, 1));
+ if (TEST_RETURN < 0)
+ tst_resm(TPASS|TTERRNO, "read failed as expected");
+ else
+ tst_resm(TFAIL, "read returned: %ld", TEST_RETURN);
+ close(fd);
+}
+
+static void test_inject(void)
+{
+ char imsg[MAX_MSGSIZE], imsg_prefixed[MAX_MSGSIZE];
+ char tmp[MAX_MSGSIZE];
+ unsigned long prefix, seqno, seqno_last = 0;
+ int i, facility, prio;
+
+ tst_resm(TINFO, "TEST: injected messages appear in /dev/kmsg");
+
+ /* test all combinations of prio 0-7, facility 0-15 */
+ for (i = 0; i < 127; i++) {
+ prio = (i & 7);
+ facility = (i >> 3);
+ sprintf(imsg, MSG_PREFIX"TEST MESSAGE %ld prio: %d, "
+ "facility: %d\n", random(), prio, facility);
+ sprintf(imsg_prefixed, "<%d>%s", i, imsg);
+
+ if (inject_msg(imsg_prefixed) == -1) {
+ tst_resm(TFAIL|TERRNO, "inject failed");
+ return;
+ }
+
+ /* check that message appears in log */
+ if (find_msg(-1, imsg, tmp, sizeof(tmp), 0) == -1) {
+ tst_resm(TFAIL, "failed to find: %s", imsg);
+ return;
+ }
+
+ /* check that facility is not 0 (LOG_KERN). */
+ if (get_msg_fields(tmp, &prefix, &seqno) != 0) {
+ tst_resm(TFAIL, "failed to parse seqid: %s", tmp);
+ return;
+ }
+ if (prefix >> 3 == 0) {
+ tst_resm(TFAIL, "facility 0 found: %s", tmp);
+ return;
+ }
+
+ /* check that seq. number grows */
+ if (seqno > seqno_last) {
+ seqno_last = seqno;
+ } else {
+ tst_resm(TFAIL, "seqno doesn't grow: %lu, "
+ "last: %lu", seqno, seqno_last);
+ return;
+ }
+ }
+
+ tst_resm(TPASS, "injected messages found in log");
+ tst_resm(TPASS, "sequence numbers grow as expected");
+}
+
+static void test_read_returns_first_message(void)
+{
+ char msg[NUM_READ_MSGS][MAX_MSGSIZE];
+ int msgs_match = 1;
+ int i;
+
+ tst_resm(TINFO, "TEST: mult. readers will get same first message");
+ for (i = 0; i < NUM_READ_MSGS; i++) {
+ if (find_msg(-1, "", msg[i], MAX_MSGSIZE, 1) != 0)
+ tst_resm(TFAIL, "failed to find any message");
+ }
+
+ for (i = 0; i < NUM_READ_MSGS-1; i++)
+ if (strlen(msg[i]) > 0 && strcmp(msg[i], msg[i+1]) != 0)
+ msgs_match = 0;
+ if (msgs_match)
+ tst_resm(TPASS, "all readers got same message on first read");
+ else
+ tst_resm(TFAIL, "readers got different messages");
+}
+
+static void test_messages_overwritten(void)
+{
+ int i, fd;
+ char msg[MAX_MSGSIZE];
+ unsigned long first_seqno, seqno;
+ char filler_str[] = MSG_PREFIX"FILLER MESSAGE TO OVERWRITE OTHERS\n";
+
+ tst_resm(TINFO, "TEST: read returns EPIPE when messages get "
+ "overwritten");
+
+ fd = open("/dev/kmsg", O_RDWR);
+ if (fd < 0)
+ tst_brkm(TBROK|TERRNO, cleanup, "failed to open /dev/kmsg");
+
+ if (find_msg(-1, "", msg, MAX_MSGSIZE, 1) == 0
+ && get_msg_fields(msg, NULL, &first_seqno) == 0) {
+ tst_resm(TINFO, "first seqno: %lu", first_seqno);
+ } else {
+ tst_brkm(TBROK, cleanup, "failed to get first seq. number");
+ }
+
+ while (1) {
+ if (find_msg(-1, "", msg, MAX_MSGSIZE, 1) != 0
+ || get_msg_fields(msg, NULL, &seqno) != 0) {
+ tst_resm(TFAIL, "failed to get first seq. number");
+ break;
+ }
+ if (first_seqno != seqno) {
+ /* first message was overwritten */
+ tst_resm(TINFO, "first seqno now: %lu", seqno);
+ break;
+ }
+ for (i = 0; i < NUM_OVERWRITE_MSGS; i++) {
+ if (inject_msg(filler_str) == -1)
+ tst_brkm(TBROK|TERRNO, cleanup,
+ "failed write to /dev/kmsg");
+ }
+ }
+
+ TEST(read(fd, msg, sizeof(msg)));
+ if (TEST_RETURN == -1 && TEST_ERRNO == EPIPE)
+ tst_resm(TPASS, "read failed with EPIPE as expected");
+ else
+ tst_resm(TFAIL|TTERRNO, "read returned: %ld", TEST_RETURN);
+ close(fd);
+}
+
+static void test_seek(void)
+{
+ int fd;
+ char msg[MAX_MSGSIZE], msg2[MAX_MSGSIZE];
+
+ tst_resm(TINFO, "TEST: seek");
+ fd = open("/dev/kmsg", O_RDWR | O_NONBLOCK);
+ if (fd < 0)
+ tst_brkm(TBROK|TERRNO, cleanup, "failed to open /dev/kmsg");
+
+ /* read() after SEEK_SET 0 returns same (first) message */
+ TEST(read(fd, msg, sizeof(msg)));
+ if (TEST_RETURN == -1)
+ tst_brkm(TBROK|TTERRNO, cleanup, "failed to read /dev/kmsg");
+ msg[TEST_RETURN] = '\0';
+
+ if (lseek(fd, 0, SEEK_SET) == -1)
+ tst_resm(TFAIL|TERRNO, "SEEK_SET 0 failed");
+
+ TEST(read(fd, msg2, sizeof(msg2)));
+ if (TEST_RETURN == -1)
+ tst_brkm(TBROK|TTERRNO, cleanup, "failed to read /dev/kmsg");
+ msg2[TEST_RETURN] = '\0';
+
+ if (strcmp(msg, msg2) != 0)
+ tst_resm(TFAIL, "SEEK_SET 0\nmsg1: %s\n, msg2: %s", msg, msg2);
+ else
+ tst_resm(TPASS, "SEEK_SET 0");
+
+ /* messages after SEEK_END 0 shouldn't contain MSG_PREFIX */
+ if (lseek(fd, 0, SEEK_END) == -1)
+ tst_resm(TFAIL|TERRNO, "lseek SEEK_END 0 failed");
+ if (find_msg(fd, MSG_PREFIX, msg, sizeof(msg), 0) != 0)
+ tst_resm(TPASS, "SEEK_END 0");
+ else
+ tst_resm(TFAIL, "SEEK_END 0 found: %s", msg);
+
+#ifdef SEEK_DATA
+ /* messages after SEEK_DATA 0 shouldn't contain MSG_PREFIX */
+ if (__NR_syslog != __LTP__NR_INVALID_SYSCALL) {
+ /* clear ring buffer */
+ if (syscall(__NR_syslog, 5, NULL, 0) == -1)
+ tst_brkm(TBROK|TERRNO, cleanup, "syslog clear failed");
+ if (lseek(fd, 0, SEEK_DATA) == -1)
+ tst_resm(TFAIL|TERRNO, "lseek SEEK_DATA 0 failed");
+ if (find_msg(fd, MSG_PREFIX, msg, sizeof(msg), 0) != 0)
+ tst_resm(TPASS, "SEEK_DATA 0");
+ else
+ tst_resm(TFAIL, "SEEK_DATA 0 found: %s", msg);
+ }
+#endif
+ close(fd);
+}
+
+int main(int argc, char *argv[])
+{
+ int lc;
+ char *msg;
+
+ msg = parse_opts(argc, argv, NULL, NULL);
+ if (msg != NULL)
+ tst_brkm(TBROK, tst_exit, "OPTION PARSING ERROR - %s", msg);
+
+ setup();
+ for (lc = 0; TEST_LOOPING(lc); lc++) {
+ /* run test_inject first so log isn't empty for other tests */
+ test_inject();
+ test_read_nonblock();
+ test_read_block();
+ test_partial_read();
+ test_read_returns_first_message();
+ test_messages_overwritten();
+ test_seek();
+ }
+ cleanup();
+ tst_exit();
+}
+
+static void setup(void)
+{
+ tst_require_root(NULL);
+ if (tst_kvercmp(3, 5, 0) < 0)
+ tst_brkm(TCONF, NULL, "This test requires kernel"
+ " >= 3.5.0");
+ srand(getpid());
+ TEST_PAUSE;
+}
+
+static void cleanup(void)
+{
+ TEST_CLEANUP;
+}
--
1.7.1
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^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [LTP] [PATCH] new testcase: kmsg01
2013-06-11 13:47 [LTP] [PATCH] new testcase: kmsg01 Jan Stancek
@ 2013-06-17 15:13 ` chrubis
[not found] ` <790434361.3815720.1371483737505.JavaMail.root@redhat.com>
0 siblings, 1 reply; 3+ messages in thread
From: chrubis @ 2013-06-17 15:13 UTC (permalink / raw)
To: Jan Stancek; +Cc: ltp-list
Hi!
> diff --git a/runtest/logging b/runtest/logging
> new file mode 100644
> index 0000000..47a667e
> --- /dev/null
> +++ b/runtest/logging
> @@ -0,0 +1 @@
> +kmsg01 kmsg01
I don't think that adding a bunch of new runtest files with one entry is
good way to go. What about adding a kernel runtest file (kernel_misc or
so) and put all the kernel tests that does not match more general group
there?
> --- /dev/null
> +++ b/testcases/kernel/logging/kmsg/kmsg01.c
> @@ -0,0 +1,513 @@
> +/*
> + * Copyright (C) 2013 Linux Test Project
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of version 2 of the GNU General Public
> + * License as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it would be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
> + *
> + * Further, this software is distributed without any warranty that it
> + * is free of the rightful claim of any third person regarding
> + * infringement or the like. Any license provided herein, whether
> + * implied or otherwise, applies only to this software file. Patent
> + * licenses, if any, provided herein do not apply to combinations of
> + * this program with other software, or any other product whatsoever.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write the Free Software
> + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
> + * 02110-1301, USA.
> + */
> +/*
> + * Test /dev/kmsg based on kernel doc: Documentation/ABI/testing/dev-kmsg
> + * - read() blocks
> + * - non-blocking read() fails with EAGAIN
> + * - partial read fails (buffer smaller than message)
> + * - can write to /dev/kmsg and message seqno grows
> + * - first read() after open() returns same message
> + * - if messages get overwritten, read() returns -EPIPE
> + * - device supports SEEK_SET, SEEK_END, SEEK_DATA
> + */
> +#define _GNU_SOURCE
> +#include <sys/types.h>
> +#include <sys/stat.h>
> +#include <sys/syscall.h>
> +#include <sys/wait.h>
> +#include <errno.h>
> +#include <fcntl.h>
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <string.h>
> +#include <unistd.h>
> +#include "config.h"
> +#include "test.h"
> +#include "usctest.h"
> +#include "safe_macros.h"
> +#include "linux_syscall_numbers.h"
> +
> +#define MSG_PREFIX "LTP KMSG "
Perhaps we should include exact test name in the prefix so it's clear
which test created them.
Something as "LTP kmsg01 "
> +#define MAX_MSGSIZE 4096
> +#define NUM_READ_MSGS 3
> +#define NUM_OVERWRITE_MSGS 1024
> +#define READ_TIMEOUT 5
> +
> +char *TCID = "kmsg01";
> +static void setup(void);
> +static void cleanup(void);
> +
> +/*
> + * inject_msg - write message to /dev/kmsg
> + * @msg: null-terminated message to inject, should end with \n
> + *
> + * RETURNS:
> + * 0 on success
> + * -1 on failure, errno reflects write() errno
> + */
> +static int inject_msg(const char *msg)
> +{
> + int f;
> + f = open("/dev/kmsg", O_RDWR);
> + if (f < 0)
> + tst_brkm(TBROK | TERRNO, cleanup, "failed to open /dev/kmsg");
> + TEST(write(f, msg, strlen(msg)));
> + close(f);
SAFE_CLOSE() ?
> + errno = TEST_ERRNO;
> + return TEST_RETURN;
> +}
> +
> +/*
> + * find_msg - find message in kernel ring buffer
> + * @fd: fd to use, if < 0 function opens /dev/kmsg itself
> + * @text_to_find: substring to look for in messages
> + * @buf: buf to store found message
> + * @bufsize: size of 'buf'
> + * @first: 1 - return first matching message
> + * 0 - return last matching message
> + * RETURNS:
> + * 0 on success
> + * -1 on failure
> + */
> +static int find_msg(int fd, const char *text_to_find, char *buf, int bufsize,
> + int first)
> +{
> + int f, msg_found = 0;
> + char *msg;
> +
> + msg = SAFE_MALLOC(cleanup, bufsize);
Is the bufsize expected to be too large to be declared on stack as
msg[bufsize] ?
> + if (fd < 0) {
> + f = open("/dev/kmsg", O_RDONLY | O_NONBLOCK);
> + if (f < 0)
> + tst_brkm(TBROK, cleanup, "failed to open /dev/kmsg");
> + } else {
> + f = fd;
> + }
> +
> + while (1) {
> + TEST(read(f, msg, bufsize));
> + if (TEST_RETURN < 0) {
> + if (TEST_ERRNO == EAGAIN)
> + /* there are no more messages */
> + break;
> + else
> + tst_brkm(TBROK|TTERRNO, cleanup,
> + "failed to read /dev/kmsg");
> + } else if (TEST_RETURN < bufsize) {
> + /* lines from kmsg are not NULL terminated */
> + msg[TEST_RETURN] = '\0';
> + if (strstr(msg, text_to_find) != NULL) {
> + memcpy(buf, msg, TEST_RETURN+1);
> + msg_found = 1;
> + if (first)
> + break;
> + }
> + }
> + };
> + free(msg);
> + if (fd < 0)
> + close(f);
> +
> + if (msg_found)
> + return 0;
> + else
> + return -1;
> +}
> +
> +static int get_msg_fields(const char *msg, unsigned long *prio,
> + unsigned long *seqno)
> +{
> + unsigned long s, p;
> + if (sscanf(msg, "%lu,%lu,", &p, &s) == 2) {
> + if (prio)
> + *prio = p;
> + if (seqno)
> + *seqno = s;
> + return 0;
> + } else {
> + return 1;
> + }
> +}
> +
> +/*
> + * timed_read - if possible reads from fd or times out
> + * @fd: fd to read from
> + * @timeout_sec: timeout in seconds
> + *
> + * RETURNS:
> + * read bytes on successful read
> + * -1 on read() error, errno reflects read() errno
> + * -2 on timeout
> + */
> +static int timed_read(int fd, int timeout_sec)
> +{
> + int ret, tmp;
> + struct timeval timeout;
> + fd_set read_fds;
> +
> + FD_ZERO(&read_fds);
> + FD_SET(fd, &read_fds);
> + timeout.tv_sec = timeout_sec;
> + timeout.tv_usec = 0;
> +
> + ret = select(fd + 1, &read_fds, 0, 0, &timeout);
> + switch (ret) {
> + case -1:
> + tst_brkm(TBROK|TERRNO, cleanup, "select failed");
> + case 0:
> + /* select timed out */
> + return -2;
> + }
> +
> + ret = read(fd, &tmp, 1);
> + return ret;
return read(fd, &tmp, 1) ? :)
> +}
> +
> +/*
> + * timed_read_file - reads file until it reaches end of file,
> + * read fails or times out.
> + * @fd: fd to read from
> + * @timeout_sec: timeout in seconds for every read attempt
> + *
> + * RETURNS:
> + * 0 on read reaching eof
> + * -1 on read error, errno reflects read() errno
> + * -2 on timeout
> + */
> +static int timed_read_file(int fd, int timeout_sec)
> +{
> + int child, status;
> + int pipefd[2];
> + char msg[MAX_MSGSIZE];
> +
> + if (pipe(pipefd) != 0)
> + tst_brkm(TBROK|TERRNO, cleanup, "pipe failed");
> +
> + child = fork();
> + switch (child) {
> + case -1:
> + tst_brkm(TBROK|TERRNO, cleanup, "failed to fork");
> + case 0:
> + /* child does all the reading and keeps writing to
> + * pipe to let parent know that it didn't block */
> + close(pipefd[0]);
> + do {
> + write(pipefd[1], "", 1);
> + TEST(read(fd, msg, MAX_MSGSIZE));
> + } while (TEST_RETURN > 0);
> +
> + close(pipefd[1]);
> + if (TEST_RETURN == -1)
> + exit(TEST_ERRNO);
> + exit(0);
> + }
> + close(pipefd[1]);
> +
> + /* parent reads pipe until it reaches eof or until read times out */
> + do {
> + TEST(timed_read(pipefd[0], timeout_sec));
> + } while (TEST_RETURN > 0);
> + close(pipefd[0]);
> +
> + if (TEST_RETURN == -2)
> + /* child is blocked, kill it */
> + kill(child, SIGTERM);
I would put the comment above the if, so that the one line block
underneath has really one line.
> + if (waitpid(child, &status, 0) == -1)
> + tst_brkm(TBROK | TERRNO, cleanup, "waitpid");
> + if (WIFEXITED(status)) {
> + if (WEXITSTATUS(status) == 0) {
> + return 0;
> + } else {
> + errno = WEXITSTATUS(status);
> + return -1;
> + }
> + }
> + return -2;
> +}
...
> +static void test_read_returns_first_message(void)
> +{
> + char msg[NUM_READ_MSGS][MAX_MSGSIZE];
> + int msgs_match = 1;
> + int i;
> +
> + tst_resm(TINFO, "TEST: mult. readers will get same first message");
> + for (i = 0; i < NUM_READ_MSGS; i++) {
> + if (find_msg(-1, "", msg[i], MAX_MSGSIZE, 1) != 0)
> + tst_resm(TFAIL, "failed to find any message");
> + }
> +
> + for (i = 0; i < NUM_READ_MSGS-1; i++)
> + if (strlen(msg[i]) > 0 && strcmp(msg[i], msg[i+1]) != 0)
> + msgs_match = 0;
> + if (msgs_match)
> + tst_resm(TPASS, "all readers got same message on first read");
> + else
> + tst_resm(TFAIL, "readers got different messages");
Is here a chance that the log would be overwritten by a kernel writing
urelated message? We do fill the log with a bunch of messages (126)
before this test, how much of the kernel log is filled by this? Looking
in the kernel .config I have LOG_BUF_SHIFT=18 which is 256KB which
should be large enough, but it could be set as low as 12 which is 4KB.
> +}
> +
> +static void test_messages_overwritten(void)
> +{
> + int i, fd;
> + char msg[MAX_MSGSIZE];
> + unsigned long first_seqno, seqno;
> + char filler_str[] = MSG_PREFIX"FILLER MESSAGE TO OVERWRITE OTHERS\n";
> +
> + tst_resm(TINFO, "TEST: read returns EPIPE when messages get "
> + "overwritten");
> +
> + fd = open("/dev/kmsg", O_RDWR);
> + if (fd < 0)
> + tst_brkm(TBROK|TERRNO, cleanup, "failed to open /dev/kmsg");
> +
> + if (find_msg(-1, "", msg, MAX_MSGSIZE, 1) == 0
> + && get_msg_fields(msg, NULL, &first_seqno) == 0) {
> + tst_resm(TINFO, "first seqno: %lu", first_seqno);
> + } else {
> + tst_brkm(TBROK, cleanup, "failed to get first seq. number");
> + }
> +
> + while (1) {
> + if (find_msg(-1, "", msg, MAX_MSGSIZE, 1) != 0
> + || get_msg_fields(msg, NULL, &seqno) != 0) {
> + tst_resm(TFAIL, "failed to get first seq. number");
> + break;
> + }
> + if (first_seqno != seqno) {
> + /* first message was overwritten */
> + tst_resm(TINFO, "first seqno now: %lu", seqno);
> + break;
> + }
> + for (i = 0; i < NUM_OVERWRITE_MSGS; i++) {
> + if (inject_msg(filler_str) == -1)
> + tst_brkm(TBROK|TERRNO, cleanup,
> + "failed write to /dev/kmsg");
> + }
> + }
> +
> + TEST(read(fd, msg, sizeof(msg)));
> + if (TEST_RETURN == -1 && TEST_ERRNO == EPIPE)
> + tst_resm(TPASS, "read failed with EPIPE as expected");
> + else
> + tst_resm(TFAIL|TTERRNO, "read returned: %ld", TEST_RETURN);
> + close(fd);
> +}
> +
> +static void test_seek(void)
> +{
> + int fd;
> + char msg[MAX_MSGSIZE], msg2[MAX_MSGSIZE];
> +
> + tst_resm(TINFO, "TEST: seek");
> + fd = open("/dev/kmsg", O_RDWR | O_NONBLOCK);
> + if (fd < 0)
> + tst_brkm(TBROK|TERRNO, cleanup, "failed to open /dev/kmsg");
> +
> + /* read() after SEEK_SET 0 returns same (first) message */
> + TEST(read(fd, msg, sizeof(msg)));
> + if (TEST_RETURN == -1)
> + tst_brkm(TBROK|TTERRNO, cleanup, "failed to read /dev/kmsg");
> + msg[TEST_RETURN] = '\0';
> +
> + if (lseek(fd, 0, SEEK_SET) == -1)
> + tst_resm(TFAIL|TERRNO, "SEEK_SET 0 failed");
> +
> + TEST(read(fd, msg2, sizeof(msg2)));
> + if (TEST_RETURN == -1)
> + tst_brkm(TBROK|TTERRNO, cleanup, "failed to read /dev/kmsg");
> + msg2[TEST_RETURN] = '\0';
> +
> + if (strcmp(msg, msg2) != 0)
> + tst_resm(TFAIL, "SEEK_SET 0\nmsg1: %s\n, msg2: %s", msg, msg2);
> + else
> + tst_resm(TPASS, "SEEK_SET 0");
> +
> + /* messages after SEEK_END 0 shouldn't contain MSG_PREFIX */
> + if (lseek(fd, 0, SEEK_END) == -1)
> + tst_resm(TFAIL|TERRNO, "lseek SEEK_END 0 failed");
> + if (find_msg(fd, MSG_PREFIX, msg, sizeof(msg), 0) != 0)
> + tst_resm(TPASS, "SEEK_END 0");
> + else
> + tst_resm(TFAIL, "SEEK_END 0 found: %s", msg);
> +
> +#ifdef SEEK_DATA
> + /* messages after SEEK_DATA 0 shouldn't contain MSG_PREFIX */
> + if (__NR_syslog != __LTP__NR_INVALID_SYSCALL) {
What about we add ltp_syscall_defined() or similar so that we don't have
to use the double underscore internal indentificator in test code?
Or use the ltp_syscall() that does that automatically and exits the test
with TCONF if not available.
> + /* clear ring buffer */
> + if (syscall(__NR_syslog, 5, NULL, 0) == -1)
> + tst_brkm(TBROK|TERRNO, cleanup, "syslog clear failed");
> + if (lseek(fd, 0, SEEK_DATA) == -1)
> + tst_resm(TFAIL|TERRNO, "lseek SEEK_DATA 0 failed");
> + if (find_msg(fd, MSG_PREFIX, msg, sizeof(msg), 0) != 0)
> + tst_resm(TPASS, "SEEK_DATA 0");
> + else
> + tst_resm(TFAIL, "SEEK_DATA 0 found: %s", msg);
> + }
> +#endif
> + close(fd);
> +}
> +
> +int main(int argc, char *argv[])
> +{
> + int lc;
> + char *msg;
> +
> + msg = parse_opts(argc, argv, NULL, NULL);
> + if (msg != NULL)
> + tst_brkm(TBROK, tst_exit, "OPTION PARSING ERROR - %s", msg);
> +
> + setup();
> + for (lc = 0; TEST_LOOPING(lc); lc++) {
> + /* run test_inject first so log isn't empty for other tests */
> + test_inject();
> + test_read_nonblock();
> + test_read_block();
> + test_partial_read();
> + test_read_returns_first_message();
> + test_messages_overwritten();
> + test_seek();
> + }
> + cleanup();
> + tst_exit();
> +}
> +
> +static void setup(void)
> +{
> + tst_require_root(NULL);
> + if (tst_kvercmp(3, 5, 0) < 0)
> + tst_brkm(TCONF, NULL, "This test requires kernel"
> + " >= 3.5.0");
> + srand(getpid());
> + TEST_PAUSE;
> +}
> +
> +static void cleanup(void)
> +{
> + TEST_CLEANUP;
> +}
--
Cyril Hrubis
chrubis@suse.cz
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^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [LTP] [PATCH] new testcase: kmsg01
[not found] ` <790434361.3815720.1371483737505.JavaMail.root@redhat.com>
@ 2013-06-17 16:21 ` chrubis
0 siblings, 0 replies; 3+ messages in thread
From: chrubis @ 2013-06-17 16:21 UTC (permalink / raw)
To: Jan Stancek; +Cc: ltp-list
Hi!
> > > +static void test_read_returns_first_message(void)
> > > +{
> > > + char msg[NUM_READ_MSGS][MAX_MSGSIZE];
> > > + int msgs_match = 1;
> > > + int i;
> > > +
> > > + tst_resm(TINFO, "TEST: mult. readers will get same first message");
> > > + for (i = 0; i < NUM_READ_MSGS; i++) {
> > > + if (find_msg(-1, "", msg[i], MAX_MSGSIZE, 1) != 0)
> > > + tst_resm(TFAIL, "failed to find any message");
> > > + }
> > > +
> > > + for (i = 0; i < NUM_READ_MSGS-1; i++)
> > > + if (strlen(msg[i]) > 0 && strcmp(msg[i], msg[i+1]) != 0)
> > > + msgs_match = 0;
> > > + if (msgs_match)
> > > + tst_resm(TPASS, "all readers got same message on first read");
> > > + else
> > > + tst_resm(TFAIL, "readers got different messages");
> >
> > Is here a chance that the log would be overwritten by a kernel writing
> > urelated message? We do fill the log with a bunch of messages (126)
> > before this test, how much of the kernel log is filled by this? Looking
> > in the kernel .config I have LOG_BUF_SHIFT=18 which is 256KB which
> > should be large enough, but it could be set as low as 12 which is 4KB.
>
> It is. Let's open extra fd, which we attempt to read only at the end.
> If reads fails with EPIPE we know that first message was overwritten.
> If that happens we can retry for NUM_READ_RETRY and repeat the test.
> If we get EPIPE in each attempt we can report TWARN.
>
Souns good.
--
Cyril Hrubis
chrubis@suse.cz
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^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2013-06-17 16:19 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2013-06-11 13:47 [LTP] [PATCH] new testcase: kmsg01 Jan Stancek
2013-06-17 15:13 ` chrubis
[not found] ` <790434361.3815720.1371483737505.JavaMail.root@redhat.com>
2013-06-17 16:21 ` chrubis
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