Annotation of embedaddon/strongswan/src/libstrongswan/threading/semaphore.c, revision 1.1
1.1 ! misho 1: /*
! 2: * Copyright (C) 2011 Tobias Brunner
! 3: * HSR Hochschule fuer Technik Rapperswil
! 4: *
! 5: * This program is free software; you can redistribute it and/or modify it
! 6: * under the terms of the GNU General Public License as published by the
! 7: * Free Software Foundation; either version 2 of the License, or (at your
! 8: * option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>.
! 9: *
! 10: * This program is distributed in the hope that it will be useful, but
! 11: * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
! 12: * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
! 13: * for more details.
! 14: */
! 15:
! 16: #include <library.h>
! 17:
! 18: #if defined(HAVE_CLOCK_GETTIME) && \
! 19: (defined(HAVE_CONDATTR_CLOCK_MONOTONIC) || \
! 20: defined(HAVE_PTHREAD_COND_TIMEDWAIT_MONOTONIC))
! 21: /* if we use MONOTONIC times, we can't use POSIX_SEMAPHORES since they use
! 22: * times based on CLOCK_REALTIME */
! 23: #undef HAVE_SEM_TIMEDWAIT
! 24: #endif /* HAVE_CLOCK_GETTIME && ... */
! 25:
! 26: #ifdef HAVE_SEM_TIMEDWAIT
! 27: #include <semaphore.h>
! 28: #else /* !HAVE_SEM_TIMEDWAIT */
! 29: #include <threading/thread.h>
! 30: #include <threading/condvar.h>
! 31: #endif /* HAVE_SEM_TIMEDWAIT */
! 32:
! 33: #include "semaphore.h"
! 34:
! 35: typedef struct private_semaphore_t private_semaphore_t;
! 36:
! 37: /**
! 38: * private data of a semaphore
! 39: */
! 40: struct private_semaphore_t {
! 41: /**
! 42: * public interface
! 43: */
! 44: semaphore_t public;
! 45:
! 46: #ifdef HAVE_SEM_TIMEDWAIT
! 47: /**
! 48: * wrapped POSIX semaphore object
! 49: */
! 50: sem_t sem;
! 51: #else /* !HAVE_SEM_TIMEDWAIT */
! 52:
! 53: /**
! 54: * Mutex to lock count variable
! 55: */
! 56: mutex_t *mutex;
! 57:
! 58: /**
! 59: * Condvar to signal count increase
! 60: */
! 61: condvar_t *cond;
! 62:
! 63: /**
! 64: * Semaphore count value
! 65: */
! 66: u_int count;
! 67: #endif /* HAVE_SEM_TIMEDWAIT */
! 68: };
! 69:
! 70: METHOD(semaphore_t, wait_, void,
! 71: private_semaphore_t *this)
! 72: {
! 73: #ifdef HAVE_SEM_TIMEDWAIT
! 74: sem_wait(&this->sem);
! 75: #else /* !HAVE_SEM_TIMEDWAIT */
! 76: this->mutex->lock(this->mutex);
! 77: thread_cleanup_push((void*)this->mutex->unlock, this->mutex);
! 78: while (this->count == 0)
! 79: {
! 80: this->cond->wait(this->cond, this->mutex);
! 81: }
! 82: this->count--;
! 83: thread_cleanup_pop(TRUE);
! 84: #endif /* HAVE_SEM_TIMEDWAIT */
! 85: }
! 86:
! 87: METHOD(semaphore_t, timed_wait_abs, bool,
! 88: private_semaphore_t *this, timeval_t tv)
! 89: {
! 90: #ifdef HAVE_SEM_TIMEDWAIT
! 91: timespec_t ts;
! 92:
! 93: ts.tv_sec = tv.tv_sec;
! 94: ts.tv_nsec = tv.tv_usec * 1000;
! 95:
! 96: /* there are errors other than ETIMEDOUT possible, but we consider them
! 97: * all as timeout */
! 98: return sem_timedwait(&this->sem, &ts) == -1;
! 99: #else /* !HAVE_SEM_TIMEDWAIT */
! 100: this->mutex->lock(this->mutex);
! 101: thread_cleanup_push((void*)this->mutex->unlock, this->mutex);
! 102: while (this->count == 0)
! 103: {
! 104: if (this->cond->timed_wait_abs(this->cond, this->mutex, tv))
! 105: {
! 106: thread_cleanup_pop(TRUE);
! 107: return TRUE;
! 108: }
! 109: }
! 110: this->count--;
! 111: thread_cleanup_pop(TRUE);
! 112: return FALSE;
! 113: #endif /* HAVE_SEM_TIMEDWAIT */
! 114: }
! 115:
! 116: METHOD(semaphore_t, timed_wait, bool,
! 117: private_semaphore_t *this, u_int timeout)
! 118: {
! 119: timeval_t tv, add;
! 120:
! 121: add.tv_sec = timeout / 1000;
! 122: add.tv_usec = (timeout % 1000) * 1000;
! 123:
! 124: time_monotonic(&tv);
! 125: timeradd(&tv, &add, &tv);
! 126:
! 127: return timed_wait_abs(this, tv);
! 128: }
! 129:
! 130: METHOD(semaphore_t, post, void,
! 131: private_semaphore_t *this)
! 132: {
! 133: #ifdef HAVE_SEM_TIMEDWAIT
! 134: sem_post(&this->sem);
! 135: #else /* !HAVE_SEM_TIMEDWAIT */
! 136: this->mutex->lock(this->mutex);
! 137: this->count++;
! 138: this->mutex->unlock(this->mutex);
! 139: this->cond->signal(this->cond);
! 140: #endif /* HAVE_SEM_TIMEDWAIT */
! 141: }
! 142:
! 143: METHOD(semaphore_t, destroy, void,
! 144: private_semaphore_t *this)
! 145: {
! 146: #ifdef HAVE_SEM_TIMEDWAIT
! 147: sem_destroy(&this->sem);
! 148: #else /* !HAVE_SEM_TIMEDWAIT */
! 149: this->cond->destroy(this->cond);
! 150: this->mutex->destroy(this->mutex);
! 151: #endif /* HAVE_SEM_TIMEDWAIT */
! 152: free(this);
! 153: }
! 154:
! 155: /*
! 156: * Described in header
! 157: */
! 158: semaphore_t *semaphore_create(u_int value)
! 159: {
! 160: private_semaphore_t *this;
! 161:
! 162: INIT(this,
! 163: .public = {
! 164: .wait = _wait_,
! 165: .timed_wait = _timed_wait,
! 166: .timed_wait_abs = _timed_wait_abs,
! 167: .post = _post,
! 168: .destroy = _destroy,
! 169: },
! 170: );
! 171:
! 172: #ifdef HAVE_SEM_TIMEDWAIT
! 173: sem_init(&this->sem, 0, value);
! 174: #else /* !HAVE_SEM_TIMEDWAIT */
! 175: this->mutex = mutex_create(MUTEX_TYPE_DEFAULT);
! 176: this->cond = condvar_create(CONDVAR_TYPE_DEFAULT);
! 177: this->count = value;
! 178: #endif /* HAVE_SEM_TIMEDWAIT */
! 179:
! 180: return &this->public;
! 181: }
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