diff options
Diffstat (limited to 'src/libstrongswan/threading/semaphore.c')
| -rw-r--r-- | src/libstrongswan/threading/semaphore.c | 179 |
1 files changed, 179 insertions, 0 deletions
diff --git a/src/libstrongswan/threading/semaphore.c b/src/libstrongswan/threading/semaphore.c new file mode 100644 index 000000000..b785ff944 --- /dev/null +++ b/src/libstrongswan/threading/semaphore.c @@ -0,0 +1,179 @@ +/* + * Copyright (C) 2011 Tobias Brunner + * Hochschule fuer Technik Rapperswil + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License as published by the + * Free Software Foundation; either version 2 of the License, or (at your + * option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>. + * + * This program 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 General Public License + * for more details. + */ + +#include <library.h> + +#if defined(HAVE_CLOCK_GETTIME) && \ + (defined(HAVE_CONDATTR_CLOCK_MONOTONIC) || \ + defined(HAVE_PTHREAD_COND_TIMEDWAIT_MONOTONIC)) +/* if we use MONOTONIC times, we can't use POSIX_SEMAPHORES since they use + * times based on CLOCK_REALTIME */ +#undef HAVE_SEM_TIMEDWAIT +#endif /* HAVE_CLOCK_GETTIME && ... */ + +#ifdef HAVE_SEM_TIMEDWAIT +#include <semaphore.h> +#else /* !HAVE_SEM_TIMEDWAIT */ +#include <threading/condvar.h> +#endif /* HAVE_SEM_TIMEDWAIT */ + +#include "semaphore.h" + +typedef struct private_semaphore_t private_semaphore_t; + +/** + * private data of a semaphore + */ +struct private_semaphore_t { + /** + * public interface + */ + semaphore_t public; + +#ifdef HAVE_SEM_TIMEDWAIT + /** + * wrapped POSIX semaphore object + */ + sem_t sem; +#else /* !HAVE_SEM_TIMEDWAIT */ + + /** + * Mutex to lock count variable + */ + mutex_t *mutex; + + /** + * Condvar to signal count increase + */ + condvar_t *cond; + + /** + * Semaphore count value + */ + u_int count; +#endif /* HAVE_SEM_TIMEDWAIT */ +}; + +METHOD(semaphore_t, wait_, void, + private_semaphore_t *this) +{ +#ifdef HAVE_SEM_TIMEDWAIT + sem_wait(&this->sem); +#else /* !HAVE_SEM_TIMEDWAIT */ + this->mutex->lock(this->mutex); + while (this->count == 0) + { + this->cond->wait(this->cond, this->mutex); + } + this->count--; + this->mutex->unlock(this->mutex); +#endif /* HAVE_SEM_TIMEDWAIT */ +} + +METHOD(semaphore_t, timed_wait_abs, bool, + private_semaphore_t *this, timeval_t tv) +{ +#ifdef HAVE_SEM_TIMEDWAIT + timespec_t ts; + + ts.tv_sec = tv.tv_sec; + ts.tv_nsec = tv.tv_usec * 1000; + + /* there are errors other than ETIMEDOUT possible, but we consider them + * all as timeout */ + return sem_timedwait(&this->sem, &ts) == -1; +#else /* !HAVE_SEM_TIMEDWAIT */ + this->mutex->lock(this->mutex); + while (this->count == 0) + { + if (this->cond->timed_wait_abs(this->cond, this->mutex, tv)) + { + this->mutex->unlock(this->mutex); + return TRUE; + } + } + this->count--; + this->mutex->unlock(this->mutex); + return FALSE; +#endif /* HAVE_SEM_TIMEDWAIT */ +} + +METHOD(semaphore_t, timed_wait, bool, + private_semaphore_t *this, u_int timeout) +{ + timeval_t tv, add; + + add.tv_sec = timeout / 1000; + add.tv_usec = (timeout % 1000) * 1000; + + time_monotonic(&tv); + timeradd(&tv, &add, &tv); + + return timed_wait_abs(this, tv); +} + +METHOD(semaphore_t, post, void, + private_semaphore_t *this) +{ +#ifdef HAVE_SEM_TIMEDWAIT + sem_post(&this->sem); +#else /* !HAVE_SEM_TIMEDWAIT */ + this->mutex->lock(this->mutex); + this->count++; + this->mutex->unlock(this->mutex); + this->cond->signal(this->cond); +#endif /* HAVE_SEM_TIMEDWAIT */ +} + +METHOD(semaphore_t, destroy, void, + private_semaphore_t *this) +{ +#ifdef HAVE_SEM_TIMEDWAIT + sem_destroy(&this->sem); +#else /* !HAVE_SEM_TIMEDWAIT */ + this->cond->destroy(this->cond); + this->mutex->destroy(this->mutex); +#endif /* HAVE_SEM_TIMEDWAIT */ + free(this); +} + +/* + * Described in header + */ +semaphore_t *semaphore_create(u_int value) +{ + private_semaphore_t *this; + + INIT(this, + .public = { + .wait = _wait_, + .timed_wait = _timed_wait, + .timed_wait_abs = _timed_wait_abs, + .post = _post, + .destroy = _destroy, + }, + ); + +#ifdef HAVE_SEM_TIMEDWAIT + sem_init(&this->sem, 0, value); +#else /* !HAVE_SEM_TIMEDWAIT */ + this->mutex = mutex_create(MUTEX_TYPE_DEFAULT); + this->cond = condvar_create(CONDVAR_TYPE_DEFAULT); + this->count = value; +#endif /* HAVE_SEM_TIMEDWAIT */ + + return &this->public; +} + |