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/******************************************************************************
*
* Copyright (C) 2014 Google, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
******************************************************************************/
#define LOG_TAG "bt_osi_semaphore"
#include <assert.h>
#include <errno.h>
#include <fcntl.h>
#include <malloc.h>
#include <string.h>
#include <sys/eventfd.h>
#include "osi/include/allocator.h"
#include "osi/include/osi.h"
#include "osi/include/log.h"
#include "osi/include/semaphore.h"
#if !defined(EFD_SEMAPHORE)
# define EFD_SEMAPHORE (1 << 0)
#endif
struct semaphore_t {
int fd;
};
semaphore_t *semaphore_new(unsigned int value) {
semaphore_t *ret = osi_malloc(sizeof(semaphore_t));
if (ret) {
ret->fd = eventfd(value, EFD_SEMAPHORE);
if (ret->fd == INVALID_FD) {
LOG_ERROR("%s unable to allocate semaphore: %s", __func__, strerror(errno));
osi_free(ret);
ret = NULL;
}
}
return ret;
}
void semaphore_free(semaphore_t *semaphore) {
if (!semaphore)
return;
if (semaphore->fd != INVALID_FD)
close(semaphore->fd);
osi_free(semaphore);
}
void semaphore_wait(semaphore_t *semaphore) {
assert(semaphore != NULL);
assert(semaphore->fd != INVALID_FD);
uint64_t value;
if (eventfd_read(semaphore->fd, &value) == -1)
LOG_ERROR("%s unable to wait on semaphore: %s", __func__, strerror(errno));
}
bool semaphore_try_wait(semaphore_t *semaphore) {
assert(semaphore != NULL);
assert(semaphore->fd != INVALID_FD);
int flags = TEMP_FAILURE_RETRY(fcntl(semaphore->fd, F_GETFL));
if (flags == -1) {
LOG_ERROR("%s unable to get flags for semaphore fd: %s", __func__, strerror(errno));
return false;
}
if (TEMP_FAILURE_RETRY(fcntl(semaphore->fd, F_SETFL, flags | O_NONBLOCK)) == -1) {
LOG_ERROR("%s unable to set O_NONBLOCK for semaphore fd: %s", __func__, strerror(errno));
return false;
}
eventfd_t value;
if (eventfd_read(semaphore->fd, &value) == -1)
return false;
if (TEMP_FAILURE_RETRY(fcntl(semaphore->fd, F_SETFL, flags)) == -1)
LOG_ERROR("%s unable to resetore flags for semaphore fd: %s", __func__, strerror(errno));
return true;
}
void semaphore_post(semaphore_t *semaphore) {
assert(semaphore != NULL);
assert(semaphore->fd != INVALID_FD);
if (eventfd_write(semaphore->fd, 1ULL) == -1)
LOG_ERROR("%s unable to post to semaphore: %s", __func__, strerror(errno));
}
int semaphore_get_fd(const semaphore_t *semaphore) {
assert(semaphore != NULL);
assert(semaphore->fd != INVALID_FD);
return semaphore->fd;
}
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