1 /*
2 * Copyright 2019 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #include "reactive_semaphore.h"
18
19 #include <error.h>
20 #include <string.h>
21 #include <sys/eventfd.h>
22 #include <unistd.h>
23
24 #include <functional>
25
26 #include "os/linux_generic/linux.h"
27 #include "os/log.h"
28
29 namespace bluetooth {
30 namespace os {
31
ReactiveSemaphore(unsigned int value)32 ReactiveSemaphore::ReactiveSemaphore(unsigned int value) : fd_(eventfd(value, EFD_SEMAPHORE | EFD_NONBLOCK)) {
33 ASSERT(fd_ != -1);
34 }
35
~ReactiveSemaphore()36 ReactiveSemaphore::~ReactiveSemaphore() {
37 int close_status;
38 RUN_NO_INTR(close_status = close(fd_));
39 ASSERT_LOG(close_status != -1, "close failed: %s", strerror(errno));
40 }
41
Decrease()42 void ReactiveSemaphore::Decrease() {
43 uint64_t val = 0;
44 auto read_result = eventfd_read(fd_, &val);
45 ASSERT_LOG(read_result != -1, "decrease failed: %s", strerror(errno));
46 }
47
Increase()48 void ReactiveSemaphore::Increase() {
49 uint64_t val = 1;
50 auto write_result = eventfd_write(fd_, val);
51 ASSERT_LOG(write_result != -1, "increase failed: %s", strerror(errno));
52 }
53
GetFd()54 int ReactiveSemaphore::GetFd() {
55 return fd_;
56 }
57
58 } // namespace os
59 } // namespace bluetooth
60