diff options
Diffstat (limited to 'nptl/sysdeps/unix/sysv/linux/sem_wait.c')
| -rw-r--r-- | nptl/sysdeps/unix/sysv/linux/sem_wait.c | 69 |
1 files changed, 62 insertions, 7 deletions
diff --git a/nptl/sysdeps/unix/sysv/linux/sem_wait.c b/nptl/sysdeps/unix/sysv/linux/sem_wait.c index e6733e88a3..12f3f16c2d 100644 --- a/nptl/sysdeps/unix/sysv/linux/sem_wait.c +++ b/nptl/sysdeps/unix/sysv/linux/sem_wait.c @@ -1,5 +1,5 @@ /* sem_wait -- wait on a semaphore. Generic futex-using version. - Copyright (C) 2003 Free Software Foundation, Inc. + Copyright (C) 2003, 2007 Free Software Foundation, Inc. This file is part of the GNU C Library. Contributed by Paul Mackerras <paulus@au.ibm.com>, 2003. @@ -28,12 +28,69 @@ #include <shlib-compat.h> +void +attribute_hidden +__sem_wait_cleanup (void *arg) +{ + struct new_sem *isem = (struct new_sem *) arg; + + atomic_decrement (&isem->nwaiters); +} + + int __new_sem_wait (sem_t *sem) { - /* First check for cancellation. */ - CANCELLATION_P (THREAD_SELF); + struct new_sem *isem = (struct new_sem *) sem; + int err; + + if (atomic_decrement_if_positive (&isem->value) > 0) + return 0; + + atomic_increment (&isem->nwaiters); + pthread_cleanup_push (__sem_wait_cleanup, isem); + + while (1) + { + /* Enable asynchronous cancellation. Required by the standard. */ + int oldtype = __pthread_enable_asynccancel (); + + err = lll_futex_wait (&isem->value, 0, + // XYZ check mutex flag + LLL_SHARED); + + /* Disable asynchronous cancellation. */ + __pthread_disable_asynccancel (oldtype); + + if (err != 0 && err != -EWOULDBLOCK) + { + __set_errno (-err); + err = -1; + break; + } + + if (atomic_decrement_if_positive (&isem->value) > 0) + { + err = 0; + break; + } + } + + pthread_cleanup_pop (0); + + atomic_decrement (&isem->nwaiters); + + return err; +} +versioned_symbol (libpthread, __new_sem_wait, sem_wait, GLIBC_2_1); + + +#if SHLIB_COMPAT (libpthread, GLIBC_2_0, GLIBC_2_1) +int +attribute_compat_text_section +__old_sem_wait (sem_t *sem) +{ int *futex = (int *) sem; int err; @@ -45,7 +102,8 @@ __new_sem_wait (sem_t *sem) /* Enable asynchronous cancellation. Required by the standard. */ int oldtype = __pthread_enable_asynccancel (); - err = lll_futex_wait (futex, 0); + /* Always assume the semaphore is shared. */ + err = lll_futex_wait (futex, 0, LLL_SHARED); /* Disable asynchronous cancellation. */ __pthread_disable_asynccancel (oldtype); @@ -56,8 +114,5 @@ __new_sem_wait (sem_t *sem) return -1; } -versioned_symbol (libpthread, __new_sem_wait, sem_wait, GLIBC_2_1); -#if SHLIB_COMPAT (libpthread, GLIBC_2_0, GLIBC_2_1) -strong_alias (__new_sem_wait, __old_sem_wait) compat_symbol (libpthread, __old_sem_wait, sem_wait, GLIBC_2_0); #endif |