posix: Correctly enable/disable cancellation on Linux posix_spawn

This patch correctly enable and disable asynchronous cancellation on
Linux posix_spawn.  Current code invert the logic by enabling and
disabling instead.  It also adds a new test to check if posix_spawn
is not a cancellation entrypoint.

Checked on x86_64, i686, powerpc64le, and aarch64.

	* nptl/Makefile (tests): Add tst-exec5.
	* nptl/tst-exec5.c: New file.
	* sysdeps/unix/sysv/linux/spawni.c (__spawni): Correctly enable and disable
	asynchronous cancellation.
This commit is contained in:
Adhemerval Zanella 2016-09-14 14:07:20 -03:00
parent aea5c83461
commit 706e6749de
4 changed files with 188 additions and 3 deletions

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@ -1,3 +1,10 @@
2016-09-20 Adhemerval Zanella <adhemerval.zanella@linaro.org>
* nptl/Makefile (tests): Add tst-exec5.
* nptl/tst-exec5.c: New file.
* sysdeps/unix/sysv/linux/spawni.c (__spawni): Correctly enable and disable
asynchronous cancellation.
2016-09-20 Samuel Thibault <samuel.thibault@ens-lyon.org> 2016-09-20 Samuel Thibault <samuel.thibault@ens-lyon.org>
* hurd/exc2signal.c: #include <hurd/signal.h> * hurd/exc2signal.c: #include <hurd/signal.h>

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@ -273,7 +273,7 @@ tests = tst-typesizes \
tst-flock1 tst-flock2 \ tst-flock1 tst-flock2 \
tst-signal1 tst-signal2 tst-signal3 tst-signal4 tst-signal5 \ tst-signal1 tst-signal2 tst-signal3 tst-signal4 tst-signal5 \
tst-signal6 tst-signal7 \ tst-signal6 tst-signal7 \
tst-exec1 tst-exec2 tst-exec3 tst-exec4 \ tst-exec1 tst-exec2 tst-exec3 tst-exec4 tst-exec5 \
tst-exit1 tst-exit2 tst-exit3 \ tst-exit1 tst-exit2 tst-exit3 \
tst-stdio1 tst-stdio2 \ tst-stdio1 tst-stdio2 \
tst-stack1 tst-stack2 tst-stack3 tst-stack4 tst-pthread-getattr \ tst-stack1 tst-stack2 tst-stack3 tst-stack4 tst-pthread-getattr \

176
nptl/tst-exec5.c Normal file
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@ -0,0 +1,176 @@
/* Check if posix_spawn does not act as a cancellation entrypoint.
Copyright (C) 2016 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <errno.h>
#include <paths.h>
#include <pthread.h>
#include <signal.h>
#include <spawn.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/wait.h>
static int do_test (void);
#define TEST_FUNCTION do_test ()
#include <test-skeleton.c>
static pthread_barrier_t b;
static pid_t pid;
static int pipefd[2];
static void *
tf (void *arg)
{
xpthread_barrier_wait (&b);
posix_spawn_file_actions_t a;
if (posix_spawn_file_actions_init (&a) != 0)
{
puts ("error: spawn_file_actions_init failed");
exit (1);
}
if (posix_spawn_file_actions_adddup2 (&a, pipefd[1], STDOUT_FILENO) != 0)
{
puts ("error: spawn_file_actions_adddup2 failed");
exit (1);
}
if (posix_spawn_file_actions_addclose (&a, pipefd[0]) != 0)
{
puts ("error: spawn_file_actions_addclose");
exit (1);
}
char *argv[] = { (char *) _PATH_BSHELL, (char *) "-c", (char *) "echo $$",
NULL };
if (posix_spawn (&pid, _PATH_BSHELL, &a, NULL, argv, NULL) != 0)
{
puts ("error: spawn failed");
exit (1);
}
return NULL;
}
static int
do_test (void)
{
/* The test basically pipe a 'echo $$' created by a thread with a
cancellation pending. It then checks if the thread is not cancelled,
the process is created and if the output is the expected one. */
if (pipe (pipefd) != 0)
{
puts ("error: pipe failed");
exit (1);
}
/* Not interested in knowing when the pipe is closed. */
if (sigignore (SIGPIPE) != 0)
{
puts ("error: sigignore failed");
exit (1);
}
/* To synchronize with the thread. */
if (pthread_barrier_init (&b, NULL, 2) != 0)
{
puts ("error: pthread_barrier_init failed");
exit (1);
}
pthread_t th = xpthread_create (NULL, &tf, NULL);
if (pthread_cancel (th) != 0)
{
puts ("error: pthread_cancel failed");
return 1;
}
xpthread_barrier_wait (&b);
if (xpthread_join (th) == PTHREAD_CANCELED)
{
puts ("error: thread cancelled");
exit (1);
}
close (pipefd[1]);
/* The global 'pid' should be set by thread posix_spawn calling. Check
below if it was executed correctly and with expected output. */
char buf[64];
ssize_t n;
bool seen_pid = false;
while (TEMP_FAILURE_RETRY ((n = read (pipefd[0], buf, sizeof (buf)))) > 0)
{
/* We only expect to read the PID. */
char *endp;
long int rpid = strtol (buf, &endp, 10);
if (*endp != '\n')
{
printf ("error: didn't parse whole line: \"%s\"\n", buf);
exit (1);
}
if (endp == buf)
{
puts ("error: read empty line");
exit (1);
}
if (rpid != pid)
{
printf ("error: found \"%s\", expected PID %ld\n", buf,
(long int) pid);
exit (1);
}
if (seen_pid)
{
puts ("error: found more than one PID line");
exit (1);
}
seen_pid = true;
}
close (pipefd[0]);
int status;
int err = waitpid (pid, &status, 0);
if (err != pid)
{
puts ("errnor: waitpid failed");
exit (1);
}
if (!seen_pid)
{
puts ("error: didn't get PID");
exit (1);
}
return 0;
}

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@ -340,7 +340,9 @@ __spawnix (pid_t * pid, const char *file,
} }
/* Disable asynchronous cancellation. */ /* Disable asynchronous cancellation. */
int cs = LIBC_CANCEL_ASYNC (); int state;
__libc_ptf_call (__pthread_setcancelstate,
(PTHREAD_CANCEL_DISABLE, &state), 0);
args.file = file; args.file = file;
args.exec = exec; args.exec = exec;
@ -386,7 +388,7 @@ __spawnix (pid_t * pid, const char *file,
__sigprocmask (SIG_SETMASK, &args.oldmask, 0); __sigprocmask (SIG_SETMASK, &args.oldmask, 0);
LIBC_CANCEL_RESET (cs); __libc_ptf_call (__pthread_setcancelstate, (state, NULL), 0);
return ec; return ec;
} }