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_POSIX_WAKEUP_FD
24
25 #include <errno.h>
26 #include <string.h>
27 #include <unistd.h>
28
29 #include <grpc/support/log.h>
30
31 #include "src/core/lib/gprpp/crash.h"
32 #include "src/core/lib/gprpp/strerror.h"
33 #include "src/core/lib/iomgr/socket_utils_posix.h"
34 #include "src/core/lib/iomgr/wakeup_fd_pipe.h"
35 #include "src/core/lib/iomgr/wakeup_fd_posix.h"
36
pipe_init(grpc_wakeup_fd * fd_info)37 static grpc_error_handle pipe_init(grpc_wakeup_fd* fd_info) {
38 int pipefd[2];
39 int r = pipe(pipefd);
40 if (0 != r) {
41 gpr_log(GPR_ERROR, "pipe creation failed (%d): %s", errno,
42 grpc_core::StrError(errno).c_str());
43 return GRPC_OS_ERROR(errno, "pipe");
44 }
45 grpc_error_handle err;
46 err = grpc_set_socket_nonblocking(pipefd[0], 1);
47 if (!err.ok()) return err;
48 err = grpc_set_socket_nonblocking(pipefd[1], 1);
49 if (!err.ok()) return err;
50 fd_info->read_fd = pipefd[0];
51 fd_info->write_fd = pipefd[1];
52 return absl::OkStatus();
53 }
54
pipe_consume(grpc_wakeup_fd * fd_info)55 static grpc_error_handle pipe_consume(grpc_wakeup_fd* fd_info) {
56 char buf[128];
57 ssize_t r;
58
59 for (;;) {
60 r = read(fd_info->read_fd, buf, sizeof(buf));
61 if (r > 0) continue;
62 if (r == 0) return absl::OkStatus();
63 switch (errno) {
64 case EAGAIN:
65 return absl::OkStatus();
66 case EINTR:
67 continue;
68 default:
69 return GRPC_OS_ERROR(errno, "read");
70 }
71 }
72 }
73
pipe_wakeup(grpc_wakeup_fd * fd_info)74 static grpc_error_handle pipe_wakeup(grpc_wakeup_fd* fd_info) {
75 char c = 0;
76 while (write(fd_info->write_fd, &c, 1) != 1 && errno == EINTR) {
77 }
78 return absl::OkStatus();
79 }
80
pipe_destroy(grpc_wakeup_fd * fd_info)81 static void pipe_destroy(grpc_wakeup_fd* fd_info) {
82 if (fd_info->read_fd != 0) close(fd_info->read_fd);
83 if (fd_info->write_fd != 0) close(fd_info->write_fd);
84 }
85
pipe_check_availability(void)86 static int pipe_check_availability(void) {
87 grpc_wakeup_fd fd;
88 fd.read_fd = fd.write_fd = -1;
89
90 if (pipe_init(&fd) == absl::OkStatus()) {
91 pipe_destroy(&fd);
92 return 1;
93 } else {
94 return 0;
95 }
96 }
97
98 const grpc_wakeup_fd_vtable grpc_pipe_wakeup_fd_vtable = {
99 pipe_init, pipe_consume, pipe_wakeup, pipe_destroy,
100 pipe_check_availability};
101
102 #endif // GPR_POSIX_WAKUP_FD
103