diff options
Diffstat (limited to 'libpthread/nptl/pthread_mutex_init.c')
| -rw-r--r-- | libpthread/nptl/pthread_mutex_init.c | 141 |
1 files changed, 141 insertions, 0 deletions
diff --git a/libpthread/nptl/pthread_mutex_init.c b/libpthread/nptl/pthread_mutex_init.c new file mode 100644 index 000000000..dd6e6d6fe --- /dev/null +++ b/libpthread/nptl/pthread_mutex_init.c @@ -0,0 +1,141 @@ +/* Copyright (C) 2002, 2003, 2004, 2005, 2006, 2007 + Free Software Foundation, Inc. + This file is part of the GNU C Library. + Contributed by Ulrich Drepper <drepper@redhat.com>, 2002. + + 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, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA + 02111-1307 USA. */ + +#include <assert.h> +#include <errno.h> +#include <string.h> +#include <bits/kernel-features.h> +#include "pthreadP.h" + +static const struct pthread_mutexattr default_attr = + { + /* Default is a normal mutex, not shared between processes. */ + .mutexkind = PTHREAD_MUTEX_NORMAL + }; + + +#ifndef __ASSUME_FUTEX_LOCK_PI +static int tpi_supported; +#endif + + +int +__pthread_mutex_init ( + pthread_mutex_t *mutex, + const pthread_mutexattr_t *mutexattr) +{ + const struct pthread_mutexattr *imutexattr; + + assert (sizeof (pthread_mutex_t) <= __SIZEOF_PTHREAD_MUTEX_T); + + imutexattr = (const struct pthread_mutexattr *) mutexattr ?: &default_attr; + + /* Sanity checks. */ + switch (__builtin_expect (imutexattr->mutexkind + & PTHREAD_MUTEXATTR_PROTOCOL_MASK, + PTHREAD_PRIO_NONE + << PTHREAD_MUTEXATTR_PROTOCOL_SHIFT)) + { + case PTHREAD_PRIO_NONE << PTHREAD_MUTEXATTR_PROTOCOL_SHIFT: + break; + + case PTHREAD_PRIO_INHERIT << PTHREAD_MUTEXATTR_PROTOCOL_SHIFT: +#ifndef __ASSUME_FUTEX_LOCK_PI + if (__builtin_expect (tpi_supported == 0, 0)) + { + int lock = 0; + INTERNAL_SYSCALL_DECL (err); + int ret = INTERNAL_SYSCALL (futex, err, 4, &lock, FUTEX_UNLOCK_PI, + 0, 0); + assert (INTERNAL_SYSCALL_ERROR_P (ret, err)); + tpi_supported = INTERNAL_SYSCALL_ERRNO (ret, err) == ENOSYS ? -1 : 1; + } + if (__builtin_expect (tpi_supported < 0, 0)) + return ENOTSUP; +#endif + break; + + default: + /* XXX: For now we don't support robust priority protected mutexes. */ + if (imutexattr->mutexkind & PTHREAD_MUTEXATTR_FLAG_ROBUST) + return ENOTSUP; + break; + } + + /* Clear the whole variable. */ + memset (mutex, '\0', __SIZEOF_PTHREAD_MUTEX_T); + + /* Copy the values from the attribute. */ + mutex->__data.__kind = imutexattr->mutexkind & ~PTHREAD_MUTEXATTR_FLAG_BITS; + + if ((imutexattr->mutexkind & PTHREAD_MUTEXATTR_FLAG_ROBUST) != 0) + { +#ifndef __ASSUME_SET_ROBUST_LIST + if ((imutexattr->mutexkind & PTHREAD_MUTEXATTR_FLAG_PSHARED) != 0 + && __set_robust_list_avail < 0) + return ENOTSUP; +#endif + + mutex->__data.__kind |= PTHREAD_MUTEX_ROBUST_NORMAL_NP; + } + + switch (imutexattr->mutexkind & PTHREAD_MUTEXATTR_PROTOCOL_MASK) + { + case PTHREAD_PRIO_INHERIT << PTHREAD_MUTEXATTR_PROTOCOL_SHIFT: + mutex->__data.__kind |= PTHREAD_MUTEX_PRIO_INHERIT_NP; + break; + + case PTHREAD_PRIO_PROTECT << PTHREAD_MUTEXATTR_PROTOCOL_SHIFT: + mutex->__data.__kind |= PTHREAD_MUTEX_PRIO_PROTECT_NP; + + int ceiling = (imutexattr->mutexkind + & PTHREAD_MUTEXATTR_PRIO_CEILING_MASK) + >> PTHREAD_MUTEXATTR_PRIO_CEILING_SHIFT; + if (! ceiling) + { + if (__sched_fifo_min_prio == -1) + __init_sched_fifo_prio (); + if (ceiling < __sched_fifo_min_prio) + ceiling = __sched_fifo_min_prio; + } + mutex->__data.__lock = ceiling << PTHREAD_MUTEX_PRIO_CEILING_SHIFT; + break; + + default: + break; + } + + /* The kernel when waking robust mutexes on exit never uses + FUTEX_PRIVATE_FLAG FUTEX_WAKE. */ + if ((imutexattr->mutexkind & (PTHREAD_MUTEXATTR_FLAG_PSHARED + | PTHREAD_MUTEXATTR_FLAG_ROBUST)) != 0) + mutex->__data.__kind |= PTHREAD_MUTEX_PSHARED_BIT; + + /* Default values: mutex not used yet. */ + // mutex->__count = 0; already done by memset + // mutex->__owner = 0; already done by memset + // mutex->__nusers = 0; already done by memset + // mutex->__spins = 0; already done by memset + // mutex->__next = NULL; already done by memset + + return 0; +} +strong_alias (__pthread_mutex_init, pthread_mutex_init) +INTDEF(__pthread_mutex_init) |