1 /*
2 *
3 * Copyright 2015 gRPC authors.
4 *
5 * Licensed under the Apache License, Version 2.0 (the "License");
6 * you may not use this file except in compliance with the License.
7 * You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 *
17 */
18
19 #include <grpc/support/port_platform.h>
20
21 #include "src/core/lib/iomgr/port.h"
22
23 #ifdef GRPC_LINUX_EVENTFD
24
25 #include <errno.h>
26 #include <sys/eventfd.h>
27 #include <unistd.h>
28
29 #include <grpc/support/log.h>
30
31 #include "src/core/lib/iomgr/wakeup_fd_posix.h"
32 #include "src/core/lib/profiling/timers.h"
33
eventfd_create(grpc_wakeup_fd * fd_info)34 static grpc_error* eventfd_create(grpc_wakeup_fd* fd_info) {
35 int efd = eventfd(0, EFD_NONBLOCK | EFD_CLOEXEC);
36 if (efd < 0) {
37 return GRPC_OS_ERROR(errno, "eventfd");
38 }
39 fd_info->read_fd = efd;
40 fd_info->write_fd = -1;
41 return GRPC_ERROR_NONE;
42 }
43
eventfd_consume(grpc_wakeup_fd * fd_info)44 static grpc_error* eventfd_consume(grpc_wakeup_fd* fd_info) {
45 eventfd_t value;
46 int err;
47 do {
48 err = eventfd_read(fd_info->read_fd, &value);
49 } while (err < 0 && errno == EINTR);
50 if (err < 0 && errno != EAGAIN) {
51 return GRPC_OS_ERROR(errno, "eventfd_read");
52 }
53 return GRPC_ERROR_NONE;
54 }
55
eventfd_wakeup(grpc_wakeup_fd * fd_info)56 static grpc_error* eventfd_wakeup(grpc_wakeup_fd* fd_info) {
57 GPR_TIMER_SCOPE("eventfd_wakeup", 0);
58 int err;
59 do {
60 err = eventfd_write(fd_info->read_fd, 1);
61 } while (err < 0 && errno == EINTR);
62 if (err < 0) {
63 return GRPC_OS_ERROR(errno, "eventfd_write");
64 }
65 return GRPC_ERROR_NONE;
66 }
67
eventfd_destroy(grpc_wakeup_fd * fd_info)68 static void eventfd_destroy(grpc_wakeup_fd* fd_info) {
69 if (fd_info->read_fd != 0) close(fd_info->read_fd);
70 }
71
eventfd_check_availability(void)72 static int eventfd_check_availability(void) {
73 const int efd = eventfd(0, 0);
74 const int is_available = efd >= 0;
75 if (is_available) close(efd);
76 return is_available;
77 }
78
79 const grpc_wakeup_fd_vtable grpc_specialized_wakeup_fd_vtable = {
80 eventfd_create, eventfd_consume, eventfd_wakeup, eventfd_destroy,
81 eventfd_check_availability};
82
83 #endif /* GRPC_LINUX_EVENTFD */
84