1 /*
2 * Copyright (C) 2021 Huawei Device Co., Ltd.
3 * Licensed under the Apache License, Version 2.0 (the "License");
4 * you may not use this file except in compliance with the License.
5 * You may obtain a copy of the License at
6 *
7 * http://www.apache.org/licenses/LICENSE-2.0
8 *
9 * Unless required by applicable law or agreed to in writing, software
10 * distributed under the License is distributed on an "AS IS" BASIS,
11 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 * See the License for the specific language governing permissions and
13 * limitations under the License.
14 */
15
16 #include "platform/include/semaphore.h"
17 #include <fcntl.h>
18 #include <stdlib.h>
19 #include <unistd.h>
20 #include <sys/eventfd.h>
21 #include "platform/include/mutex.h"
22 #include "platform/include/platform_def.h"
23 #include "securec.h"
24
25 #if !defined(EFD_SEMAPHORE)
26 #define EFD_SEMAPHORE (1 << 0)
27 #endif
28
29 typedef struct Semaphore {
30 Mutex *mutex;
31 int fd;
32 } SemaphoreInternal;
33
SemaphoreCreate(uint32_t val)34 Semaphore *SemaphoreCreate(uint32_t val)
35 {
36 int efd = eventfd(val, EFD_SEMAPHORE);
37 if (efd == -1) {
38 LOG_ERROR("SemaphoreCreate: create eventfd failed, error no: %{public}d.", errno);
39 return NULL;
40 }
41
42 Mutex *mutex = MutexCreate();
43 if (mutex == NULL) {
44 close(efd);
45 LOG_ERROR("SemaphoreCreate: create Mutex failed.");
46 return NULL;
47 }
48
49 Semaphore *semaphore = (Semaphore *)malloc(sizeof(Semaphore));
50 if (semaphore == NULL) {
51 close(efd);
52 MutexDelete(mutex);
53 LOG_ERROR("SemaphoreCreate: create Semaphore failed.");
54 return NULL;
55 }
56 (void)memset_s(semaphore, sizeof(Semaphore), 0, sizeof(Semaphore));
57 semaphore->fd = efd;
58 semaphore->mutex = mutex;
59
60 return semaphore;
61 }
62
SemaphoreDelete(Semaphore * sem)63 void SemaphoreDelete(Semaphore *sem)
64 {
65 if (sem == NULL) {
66 return;
67 }
68
69 if (sem->fd != -1) {
70 close(sem->fd);
71 }
72
73 MutexDelete(sem->mutex);
74 free(sem);
75 }
76
SemaphoreWait(const Semaphore * sem)77 void SemaphoreWait(const Semaphore *sem)
78 {
79 ASSERT(sem);
80
81 eventfd_t val;
82 eventfd_read(sem->fd, &val);
83 }
84
SemaphoreTryWait(Semaphore * sem)85 int32_t SemaphoreTryWait(Semaphore *sem)
86 {
87 ASSERT(sem);
88
89 MutexLock(sem->mutex);
90 int flags = fcntl(sem->fd, F_GETFL);
91 if (flags == -1) {
92 goto ERROR;
93 }
94
95 if (fcntl(sem->fd, F_SETFL, flags | EFD_NONBLOCK) == -1) {
96 goto ERROR;
97 }
98
99 eventfd_t val;
100 if (eventfd_read(sem->fd, &val) == -1) {
101 goto ERROR;
102 }
103
104 if (fcntl(sem->fd, F_SETFL, flags) == -1) {
105 goto ERROR;
106 }
107
108 MutexUnlock(sem->mutex);
109 return 0;
110
111 ERROR:
112 MutexUnlock(sem->mutex);
113 return -1;
114 }
115
SemaphorePost(const Semaphore * sem)116 void SemaphorePost(const Semaphore *sem)
117 {
118 ASSERT(sem);
119
120 eventfd_write(sem->fd, 1);
121 }
122
SemaphoreTryPost(Semaphore * sem)123 int32_t SemaphoreTryPost(Semaphore *sem)
124 {
125 ASSERT(sem);
126
127 MutexLock(sem->mutex);
128 int flags = fcntl(sem->fd, F_GETFL);
129 if (flags == -1) {
130 goto ERROR;
131 }
132
133 if (fcntl(sem->fd, F_SETFL, flags | EFD_NONBLOCK) == -1) {
134 goto ERROR;
135 }
136
137 if (eventfd_write(sem->fd, 1) == -1) {
138 goto ERROR;
139 }
140
141 if (fcntl(sem->fd, F_SETFL, flags) == -1) {
142 goto ERROR;
143 }
144
145 MutexUnlock(sem->mutex);
146 return 0;
147
148 ERROR:
149 MutexUnlock(sem->mutex);
150 return -1;
151 }
152
SemaphoreGetfd(const Semaphore * sem)153 int SemaphoreGetfd(const Semaphore *sem)
154 {
155 ASSERT(sem);
156
157 return sem->fd;
158 }
159