rt: Set shm_open as a non cancellation point (BZ #18243)

This patch changes shm_open to not act as a cancellation point.
Cancellation is disable at start and reenable in function exit.
It fixes BZ #18243.

Tested on x86_64 and i686.

	[BZ #18243]
	* rt/Makefile (test): Add tst-shm-cancel.
	* rt/tst-shm-cancel.c: New file.
	* sysdeps/posix/shm_open.c: Disable asynchronous cancellation.
This commit is contained in:
Adhemerval Zanella 2016-08-22 10:31:42 -03:00
parent 47677f2edc
commit fbc994921b
4 changed files with 143 additions and 1 deletions

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@ -1,5 +1,10 @@
2016-09-15 Adhemerval Zanella <adhemerval.zanella@linaro.org> 2016-09-15 Adhemerval Zanella <adhemerval.zanella@linaro.org>
[BZ #18243]
* rt/Makefile (test): Add tst-shm-cancel.
* rt/tst-shm-cancel.c: New file.
* sysdeps/posix/shm_open.c: Disable asynchronous cancellation.
[BZ #18243] [BZ #18243]
* nptl/pthreadP.h (__pthread_testcancel): Add prototype and hidden_proto. * nptl/pthreadP.h (__pthread_testcancel): Add prototype and hidden_proto.
* nptl/pthread_testcancel.c (pthread_cancel): Add internal aliais * nptl/pthread_testcancel.c (pthread_cancel): Add internal aliais

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@ -53,7 +53,7 @@ tests := tst-shm tst-clock tst-clock_nanosleep tst-timer tst-timer2 \
tst-timer3 tst-timer4 tst-timer5 \ tst-timer3 tst-timer4 tst-timer5 \
tst-cpuclock1 tst-cpuclock2 \ tst-cpuclock1 tst-cpuclock2 \
tst-cputimer1 tst-cputimer2 tst-cputimer3 \ tst-cputimer1 tst-cputimer2 tst-cputimer3 \
tst-clock2 tst-clock2 tst-shm-cancel
extra-libs := librt extra-libs := librt
extra-libs-others := $(extra-libs) extra-libs-others := $(extra-libs)

130
rt/tst-shm-cancel.c Normal file
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@ -0,0 +1,130 @@
/* Test for shm_open cancellation handling: BZ #18243.
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 <pthread.h>
#include <sys/mman.h>
#include <semaphore.h>
#include <stdio.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include <stdlib.h>
static sem_t sem; /* Use to sync with thread start. */
static const char shm_name[] = "/glibc-shm_open-cancel";
static void
remove_shm (int status, void *arg)
{
shm_unlink (shm_name);
}
static void *
tf (void *arg)
{
pthread_setcancelstate (PTHREAD_CANCEL_DISABLE, 0);
if (sem_wait (&sem) != 0)
{
printf ("error: sem_wait failed: %m");
exit (1);
}
if (pthread_setcancelstate (PTHREAD_CANCEL_ENABLE, 0) != 0)
{
printf ("error: pthread_setcancelstate failed: %m");
exit (1);
}
/* Neither sem_unlink or sem_open should act on thread cancellation. */
shm_unlink (shm_name);
on_exit (remove_shm, NULL);
int fd = shm_open (shm_name, O_CREAT, 0600);
if (fd == -1)
{
int exit_code;
if (errno == ENOSYS || errno == EACCES)
exit_code = 77;
else
exit_code = 1;
exit (exit_code);
}
if (pthread_setcancelstate (PTHREAD_CANCEL_DISABLE, 0) != 0)
{
printf ("error: pthread_setcancelstate failed: %m");
exit (1);
}
if (close (fd) != 0)
{
printf ("error: pthread_setcancelstate failed: %m");
exit (1);
}
return NULL;
}
static int
do_test (void)
{
pthread_t td;
if (sem_init (&sem, 0, 0))
{
printf ("error: sem_init failed: %m\n");
exit (1);
}
if (pthread_create (&td, NULL, tf, NULL) != 0)
{
printf ("error: pthread_create failed: %m\n");
exit (1);
}
if (pthread_cancel (td) != 0)
{
printf ("error: pthread_cancel failed: %m\n");
exit (1);
}
if (sem_post (&sem) != 0)
{
printf ("error: sem_post failed: %m\n");
exit (1);
}
void *r;
if (pthread_join (td, &r) != 0)
{
printf ("error: pthread_join failed: %m\n");
exit (1);
}
if (r == PTHREAD_CANCELED)
{
puts ("error: pthread_join returned PTHREAD_CANCELED");
exit (1);
}
return 0;
}
#define TEST_FUNCTION do_test ()
#include <test-skeleton.c>

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@ -40,6 +40,11 @@ shm_open (const char *name, int oflag, mode_t mode)
# ifdef O_CLOEXEC # ifdef O_CLOEXEC
oflag |= O_CLOEXEC; oflag |= O_CLOEXEC;
# endif # endif
/* Disable asynchronous cancellation. */
int state;
pthread_setcancelstate (PTHREAD_CANCEL_DISABLE, &state);
int fd = open (shm_name, oflag, mode); int fd = open (shm_name, oflag, mode);
if (fd == -1 && __glibc_unlikely (errno == EISDIR)) if (fd == -1 && __glibc_unlikely (errno == EISDIR))
/* It might be better to fold this error with EINVAL since /* It might be better to fold this error with EINVAL since
@ -70,6 +75,8 @@ shm_open (const char *name, int oflag, mode_t mode)
} }
# endif # endif
pthread_setcancelstate (state, NULL);
return fd; return fd;
} }