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nptl: Set sem_open as a non cancellation point (BZ #15765) 

This patch changes sem_open to not act as a cancellation point.
Cancellation is disable at start and reenable in function exit.
It fixes BZ #15765.

Tested on x86_64 and i686.

	[BZ #15765]
	* nptl/Makefile (tests): Add tst-sem16.
	* nptl/tst-sem16.c: New file.
	* nptl/sem_open.c (sem_open): Disable asynchronous cancellation.
This commit is contained in:
Adhemerval Zanella 2016-08-20 11:23:08 -03:00
parent 980d25d53e
commit 91dd866ff1
4 changed files with 157 additions and 5 deletions
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5
ChangeLog
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@ -1,5 +1,10 @@
2016-09-15 Adhemerval Zanella <adhemerval.zanella@linaro.org>
[BZ #15765]
* nptl/Makefile (tests): Add tst-sem16.
* nptl/tst-sem16.c: New file.
* nptl/sem_open.c (sem_open): Disable asynchronous cancellation.
* nptl/sem_open.c (sem_open): Init pad value to 0.
* sysdeps/sparc/sparc32/sem_open.c: Remove file.
* sysdeps/sparc/sparc32/sparcv9/sem_open.c: Likewise.

2
nptl/Makefile
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@ -246,7 +246,7 @@ tests = tst-typesizes \
tst-key1 tst-key2 tst-key3 tst-key4 \
tst-sem1 tst-sem2 tst-sem3 tst-sem4 tst-sem5 tst-sem6 tst-sem7 \
tst-sem8 tst-sem9 tst-sem10 tst-sem11 tst-sem12 tst-sem13 tst-sem14 \
tst-sem15 \
tst-sem15 tst-sem16 \
tst-barrier1 tst-barrier2 tst-barrier3 tst-barrier4 tst-barrier5 \
tst-align tst-align3 \
tst-basic1 tst-basic2 tst-basic3 tst-basic4 tst-basic5 tst-basic6 \

25
nptl/sem_open.c
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@ -31,7 +31,7 @@
#include "semaphoreP.h"
#include <shm-directory.h>
#include <futex-internal.h>
#include <libc-lock.h>
/* Comparison function for search of existing mapping. */
int
@ -153,6 +153,13 @@ sem_open (const char *name, int oflag, ...)
/* Create the name of the final file in local variable SHM_NAME. */
SHM_GET_NAME (EINVAL, SEM_FAILED, SEM_SHM_PREFIX);
/* Disable asynchronous cancellation. */
#ifdef __libc_ptf_call
int state;
__libc_ptf_call (__pthread_setcancelstate,
(PTHREAD_CANCEL_DISABLE, &state), 0);
#endif
/* If the semaphore object has to exist simply open it. */
if ((oflag & O_CREAT) == 0 || (oflag & O_EXCL) == 0)
{
@ -193,7 +200,8 @@ sem_open (const char *name, int oflag, ...)
if (value > SEM_VALUE_MAX)
{
__set_errno (EINVAL);
return SEM_FAILED;
result = SEM_FAILED;
goto out;
}
/* Create the initial file content. */
@ -233,7 +241,10 @@ sem_open (const char *name, int oflag, ...)
mode cannot later be set since then we cannot apply the
file create mask. */
if (__mktemp (tmpfname) == NULL)
return SEM_FAILED;
{
result = SEM_FAILED;
goto out;
}
/* Open the file. Make sure we do not overwrite anything. */
fd = __libc_open (tmpfname, O_RDWR | O_CREAT | O_EXCL, mode);
@ -247,7 +258,8 @@ sem_open (const char *name, int oflag, ...)
__set_errno (EAGAIN);
}
return SEM_FAILED;
result = SEM_FAILED;
goto out;
}
/* We got a file. */
@ -308,5 +320,10 @@ sem_open (const char *name, int oflag, ...)
errno = save;
}
out:
#ifdef __libc_ptf_call
__libc_ptf_call (__pthread_setcancelstate, (state, NULL), 0);
#endif
return result;
}

130
nptl/tst-sem16.c Normal file
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@ -0,0 +1,130 @@
/* Test for sem_open cancellation handling: BZ #15765.
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 pipe_name[] = "/glibc-tst-sem16";
static void
remove_sem (int status, void *arg)
{
sem_unlink (arg);
}
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. */
sem_unlink (pipe_name);
on_exit (remove_sem, (void *) pipe_name);
sem_t *s = sem_open (pipe_name, O_CREAT, 0600, 1);
if (s == SEM_FAILED)
{
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 (sem_close (s) != 0)
{
printf ("error: sem_close 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>