1 // Copyright 2022 The gRPC Authors
2 //
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 #include <grpc/support/port_platform.h>
16
17 #include <utility>
18
19 #include "absl/strings/str_cat.h"
20 #include "absl/strings/string_view.h"
21
22 #include "src/core/lib/gprpp/crash.h" // IWYU pragma: keep
23 #include "src/core/lib/iomgr/port.h"
24
25 #ifdef GRPC_LINUX_EVENTFD
26
27 #include <errno.h>
28 #include <sys/eventfd.h>
29 #include <unistd.h>
30
31 #include "src/core/lib/event_engine/posix_engine/wakeup_fd_posix.h"
32 #endif
33
34 #include "src/core/lib/event_engine/posix_engine/wakeup_fd_eventfd.h"
35 #include "src/core/lib/gprpp/strerror.h"
36
37 namespace grpc_event_engine {
38 namespace experimental {
39
40 #ifdef GRPC_LINUX_EVENTFD
41
Init()42 absl::Status EventFdWakeupFd::Init() {
43 int read_fd = eventfd(0, EFD_NONBLOCK | EFD_CLOEXEC);
44 int write_fd = -1;
45 if (read_fd < 0) {
46 return absl::Status(absl::StatusCode::kInternal,
47 absl::StrCat("eventfd: ", grpc_core::StrError(errno)));
48 }
49 SetWakeupFds(read_fd, write_fd);
50 return absl::OkStatus();
51 }
52
ConsumeWakeup()53 absl::Status EventFdWakeupFd::ConsumeWakeup() {
54 eventfd_t value;
55 int err;
56 do {
57 err = eventfd_read(ReadFd(), &value);
58 } while (err < 0 && errno == EINTR);
59 if (err < 0 && errno != EAGAIN) {
60 return absl::Status(
61 absl::StatusCode::kInternal,
62 absl::StrCat("eventfd_read: ", grpc_core::StrError(errno)));
63 }
64 return absl::OkStatus();
65 }
66
Wakeup()67 absl::Status EventFdWakeupFd::Wakeup() {
68 int err;
69 do {
70 err = eventfd_write(ReadFd(), 1);
71 } while (err < 0 && errno == EINTR);
72 if (err < 0) {
73 return absl::Status(
74 absl::StatusCode::kInternal,
75 absl::StrCat("eventfd_write: ", grpc_core::StrError(errno)));
76 }
77 return absl::OkStatus();
78 }
79
~EventFdWakeupFd()80 EventFdWakeupFd::~EventFdWakeupFd() {
81 if (ReadFd() != 0) {
82 close(ReadFd());
83 }
84 }
85
IsSupported()86 bool EventFdWakeupFd::IsSupported() {
87 EventFdWakeupFd event_fd_wakeup_fd;
88 return event_fd_wakeup_fd.Init().ok();
89 }
90
91 absl::StatusOr<std::unique_ptr<WakeupFd>>
CreateEventFdWakeupFd()92 EventFdWakeupFd::CreateEventFdWakeupFd() {
93 static bool kIsEventFdWakeupFdSupported = EventFdWakeupFd::IsSupported();
94 if (kIsEventFdWakeupFdSupported) {
95 auto event_fd_wakeup_fd = std::make_unique<EventFdWakeupFd>();
96 auto status = event_fd_wakeup_fd->Init();
97 if (status.ok()) {
98 return std::unique_ptr<WakeupFd>(std::move(event_fd_wakeup_fd));
99 }
100 return status;
101 }
102 return absl::NotFoundError("Eventfd wakeup fd is not supported");
103 }
104
105 #else // GRPC_LINUX_EVENTFD
106
107 #include "src/core/lib/gprpp/crash.h"
108
109 absl::Status EventFdWakeupFd::Init() { grpc_core::Crash("unimplemented"); }
110
111 absl::Status EventFdWakeupFd::ConsumeWakeup() {
112 grpc_core::Crash("unimplemented");
113 }
114
115 absl::Status EventFdWakeupFd::Wakeup() { grpc_core::Crash("unimplemented"); }
116
117 bool EventFdWakeupFd::IsSupported() { return false; }
118
119 absl::StatusOr<std::unique_ptr<WakeupFd>>
120 EventFdWakeupFd::CreateEventFdWakeupFd() {
121 return absl::NotFoundError("Eventfd wakeup fd is not supported");
122 }
123
124 #endif // GRPC_LINUX_EVENTFD
125
126 } // namespace experimental
127 } // namespace grpc_event_engine
128