From: Adhemerval Zanella Date: Mon, 22 Aug 2016 13:31:42 +0000 (-0300) Subject: rt: Set shm_open as a non cancellation point (BZ #18243) X-Git-Tag: glibc-2.25~530 X-Git-Url: https://sourceware.org/git/?a=commitdiff_plain;h=fbc994921b459d57b681a926780933a20745edf5;p=glibc.git 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. --- diff --git a/ChangeLog b/ChangeLog index 6225e195f1..99af3a7096 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,5 +1,10 @@ 2016-09-15 Adhemerval Zanella + [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] * nptl/pthreadP.h (__pthread_testcancel): Add prototype and hidden_proto. * nptl/pthread_testcancel.c (pthread_cancel): Add internal aliais diff --git a/rt/Makefile b/rt/Makefile index cfa68379c5..7593b11652 100644 --- a/rt/Makefile +++ b/rt/Makefile @@ -53,7 +53,7 @@ tests := tst-shm tst-clock tst-clock_nanosleep tst-timer tst-timer2 \ tst-timer3 tst-timer4 tst-timer5 \ tst-cpuclock1 tst-cpuclock2 \ tst-cputimer1 tst-cputimer2 tst-cputimer3 \ - tst-clock2 + tst-clock2 tst-shm-cancel extra-libs := librt extra-libs-others := $(extra-libs) diff --git a/rt/tst-shm-cancel.c b/rt/tst-shm-cancel.c new file mode 100644 index 0000000000..43d9ee540d --- /dev/null +++ b/rt/tst-shm-cancel.c @@ -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 + . */ + +#include +#include +#include +#include +#include +#include +#include +#include + +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 diff --git a/sysdeps/posix/shm_open.c b/sysdeps/posix/shm_open.c index f2961620b4..0182e7baf5 100644 --- a/sysdeps/posix/shm_open.c +++ b/sysdeps/posix/shm_open.c @@ -40,6 +40,11 @@ shm_open (const char *name, int oflag, mode_t mode) # ifdef O_CLOEXEC oflag |= O_CLOEXEC; # endif + + /* Disable asynchronous cancellation. */ + int state; + pthread_setcancelstate (PTHREAD_CANCEL_DISABLE, &state); + int fd = open (shm_name, oflag, mode); if (fd == -1 && __glibc_unlikely (errno == EISDIR)) /* 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 + pthread_setcancelstate (state, NULL); + return fd; }