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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 <grpc/grpc.h>
22 
23 #include "src/core/lib/iomgr/port.h"
24 
25 #ifdef GRPC_POSIX_SOCKET_EV
26 
27 #include <string.h>
28 
29 #include "absl/strings/str_format.h"
30 #include "absl/strings/str_split.h"
31 
32 #include <grpc/support/alloc.h>
33 #include <grpc/support/log.h>
34 #include <grpc/support/string_util.h>
35 
36 #include "src/core/lib/config/config_vars.h"
37 #include "src/core/lib/debug/trace.h"
38 #include "src/core/lib/gpr/useful.h"
39 #include "src/core/lib/gprpp/crash.h"
40 #include "src/core/lib/iomgr/ev_epoll1_linux.h"
41 #include "src/core/lib/iomgr/ev_poll_posix.h"
42 #include "src/core/lib/iomgr/ev_posix.h"
43 #include "src/core/lib/iomgr/internal_errqueue.h"
44 
45 grpc_core::DebugOnlyTraceFlag grpc_polling_trace(
46     false, "polling");  // Disabled by default
47 
48 // Traces fd create/close operations
49 grpc_core::DebugOnlyTraceFlag grpc_fd_trace(false, "fd_trace");
50 grpc_core::DebugOnlyTraceFlag grpc_trace_fd_refcount(false, "fd_refcount");
51 grpc_core::DebugOnlyTraceFlag grpc_polling_api_trace(false, "polling_api");
52 
53 // Polling API trace only enabled in debug builds
54 #ifndef NDEBUG
55 #define GRPC_POLLING_API_TRACE(format, ...)                  \
56   if (GRPC_TRACE_FLAG_ENABLED(grpc_polling_api_trace)) {     \
57     gpr_log(GPR_INFO, "(polling-api) " format, __VA_ARGS__); \
58   }
59 #else
60 #define GRPC_POLLING_API_TRACE(...)
61 #endif  // NDEBUG
62 
63 /// Default poll() function - a pointer so that it can be overridden by some
64 /// tests
65 #ifndef GPR_AIX
66 grpc_poll_function_type grpc_poll_function = poll;
67 #else
aix_poll(struct pollfd fds[],nfds_t nfds,int timeout)68 int aix_poll(struct pollfd fds[], nfds_t nfds, int timeout) {
69   return poll(fds, nfds, timeout);
70 }
71 grpc_poll_function_type grpc_poll_function = aix_poll;
72 #endif  // GPR_AIX
73 
74 grpc_wakeup_fd grpc_global_wakeup_fd;
75 
76 static const grpc_event_engine_vtable* g_event_engine = nullptr;
77 static gpr_once g_choose_engine = GPR_ONCE_INIT;
78 
79 // The global array of event-engine factories. Each entry is a pair with a name
80 // and an event-engine generator function (nullptr if there is no generator
81 // registered for this name). The middle entries are the engines predefined by
82 // open-source gRPC. The head entries represent an opportunity for specific
83 // high-priority custom pollers to be added by the initializer plugins of
84 // custom-built gRPC libraries. The tail entries represent the same, but for
85 // low-priority custom pollers. The actual poller selected is either the first
86 // available one in the list if no specific poller is requested, or the first
87 // specific poller that is requested by name in the GRPC_POLL_STRATEGY
88 // environment variable if that variable is set (which should be a
89 // comma-separated list of one or more event engine names)
90 static const grpc_event_engine_vtable* g_vtables[] = {
91     nullptr,
92     nullptr,
93     nullptr,
94     nullptr,
95     &grpc_ev_epoll1_posix,
96     &grpc_ev_poll_posix,
97     &grpc_ev_none_posix,
98     nullptr,
99     nullptr,
100     nullptr,
101     nullptr,
102 };
103 
is(absl::string_view want,absl::string_view have)104 static bool is(absl::string_view want, absl::string_view have) {
105   return want == "all" || want == have;
106 }
107 
try_engine(absl::string_view engine)108 static void try_engine(absl::string_view engine) {
109   for (size_t i = 0; i < GPR_ARRAY_SIZE(g_vtables); i++) {
110     if (g_vtables[i] != nullptr && is(engine, g_vtables[i]->name) &&
111         g_vtables[i]->check_engine_available(engine == g_vtables[i]->name)) {
112       g_event_engine = g_vtables[i];
113       gpr_log(GPR_DEBUG, "Using polling engine: %s", g_event_engine->name);
114       return;
115     }
116   }
117 }
118 
119 // Call this before calling grpc_event_engine_init()
grpc_register_event_engine_factory(const grpc_event_engine_vtable * vtable,bool add_at_head)120 void grpc_register_event_engine_factory(const grpc_event_engine_vtable* vtable,
121                                         bool add_at_head) {
122   const grpc_event_engine_vtable** first_null = nullptr;
123   const grpc_event_engine_vtable** last_null = nullptr;
124 
125   // Overwrite an existing registration if already registered
126   for (size_t i = 0; i < GPR_ARRAY_SIZE(g_vtables); i++) {
127     if (g_vtables[i] == nullptr) {
128       if (first_null == nullptr) first_null = &g_vtables[i];
129       last_null = &g_vtables[i];
130     } else if (0 == strcmp(g_vtables[i]->name, vtable->name)) {
131       g_vtables[i] = vtable;
132       return;
133     }
134   }
135 
136   *(add_at_head ? first_null : last_null) = vtable;
137 }
138 
139 // If grpc_event_engine_init() has been called, returns the poll_strategy_name.
140 //  Otherwise, returns nullptr.
grpc_get_poll_strategy_name()141 const char* grpc_get_poll_strategy_name() { return g_event_engine->name; }
142 
grpc_event_engine_init(void)143 void grpc_event_engine_init(void) {
144   gpr_once_init(&g_choose_engine, []() {
145     auto value = grpc_core::ConfigVars::Get().PollStrategy();
146     for (auto trial : absl::StrSplit(value, ',')) {
147       try_engine(trial);
148       if (g_event_engine != nullptr) return;
149     }
150 
151     if (g_event_engine == nullptr) {
152       grpc_core::Crash(
153           absl::StrFormat("No event engine could be initialized from %s",
154                           std::string(value).c_str()));
155     }
156   });
157   g_event_engine->init_engine();
158 }
159 
grpc_event_engine_shutdown(void)160 void grpc_event_engine_shutdown(void) { g_event_engine->shutdown_engine(); }
161 
grpc_event_engine_can_track_errors(void)162 bool grpc_event_engine_can_track_errors(void) {
163   // Only track errors if platform supports errqueue.
164   return grpc_core::KernelSupportsErrqueue() && g_event_engine->can_track_err;
165 }
166 
grpc_event_engine_run_in_background(void)167 bool grpc_event_engine_run_in_background(void) {
168   // g_event_engine is nullptr when using a custom iomgr.
169   return g_event_engine != nullptr && g_event_engine->run_in_background;
170 }
171 
grpc_fd_create(int fd,const char * name,bool track_err)172 grpc_fd* grpc_fd_create(int fd, const char* name, bool track_err) {
173   GRPC_POLLING_API_TRACE("fd_create(%d, %s, %d)", fd, name, track_err);
174   GRPC_FD_TRACE("fd_create(%d, %s, %d)", fd, name, track_err);
175   return g_event_engine->fd_create(
176       fd, name, track_err && grpc_event_engine_can_track_errors());
177 }
178 
grpc_fd_wrapped_fd(grpc_fd * fd)179 int grpc_fd_wrapped_fd(grpc_fd* fd) {
180   return g_event_engine->fd_wrapped_fd(fd);
181 }
182 
grpc_fd_orphan(grpc_fd * fd,grpc_closure * on_done,int * release_fd,const char * reason)183 void grpc_fd_orphan(grpc_fd* fd, grpc_closure* on_done, int* release_fd,
184                     const char* reason) {
185   GRPC_POLLING_API_TRACE("fd_orphan(%d, %p, %p, %s)", grpc_fd_wrapped_fd(fd),
186                          on_done, release_fd, reason);
187   GRPC_FD_TRACE("grpc_fd_orphan, fd:%d closed", grpc_fd_wrapped_fd(fd));
188 
189   g_event_engine->fd_orphan(fd, on_done, release_fd, reason);
190 }
191 
grpc_fd_set_pre_allocated(grpc_fd * fd)192 void grpc_fd_set_pre_allocated(grpc_fd* fd) {
193   GRPC_POLLING_API_TRACE("fd_set_pre_allocated(%d)", grpc_fd_wrapped_fd(fd));
194   GRPC_FD_TRACE("fd_set_pre_allocated(%d)", grpc_fd_wrapped_fd(fd));
195   g_event_engine->fd_set_pre_allocated(fd);
196 }
197 
grpc_fd_shutdown(grpc_fd * fd,grpc_error_handle why)198 void grpc_fd_shutdown(grpc_fd* fd, grpc_error_handle why) {
199   GRPC_POLLING_API_TRACE("fd_shutdown(%d)", grpc_fd_wrapped_fd(fd));
200   GRPC_FD_TRACE("fd_shutdown(%d)", grpc_fd_wrapped_fd(fd));
201   g_event_engine->fd_shutdown(fd, why);
202 }
203 
grpc_fd_is_shutdown(grpc_fd * fd)204 bool grpc_fd_is_shutdown(grpc_fd* fd) {
205   return g_event_engine->fd_is_shutdown(fd);
206 }
207 
grpc_fd_notify_on_read(grpc_fd * fd,grpc_closure * closure)208 void grpc_fd_notify_on_read(grpc_fd* fd, grpc_closure* closure) {
209   g_event_engine->fd_notify_on_read(fd, closure);
210 }
211 
grpc_fd_notify_on_write(grpc_fd * fd,grpc_closure * closure)212 void grpc_fd_notify_on_write(grpc_fd* fd, grpc_closure* closure) {
213   g_event_engine->fd_notify_on_write(fd, closure);
214 }
215 
grpc_fd_notify_on_error(grpc_fd * fd,grpc_closure * closure)216 void grpc_fd_notify_on_error(grpc_fd* fd, grpc_closure* closure) {
217   g_event_engine->fd_notify_on_error(fd, closure);
218 }
219 
grpc_fd_set_readable(grpc_fd * fd)220 void grpc_fd_set_readable(grpc_fd* fd) { g_event_engine->fd_set_readable(fd); }
221 
grpc_fd_set_writable(grpc_fd * fd)222 void grpc_fd_set_writable(grpc_fd* fd) { g_event_engine->fd_set_writable(fd); }
223 
grpc_fd_set_error(grpc_fd * fd)224 void grpc_fd_set_error(grpc_fd* fd) { g_event_engine->fd_set_error(fd); }
225 
pollset_size(void)226 static size_t pollset_size(void) { return g_event_engine->pollset_size; }
227 
pollset_init(grpc_pollset * pollset,gpr_mu ** mu)228 static void pollset_init(grpc_pollset* pollset, gpr_mu** mu) {
229   GRPC_POLLING_API_TRACE("pollset_init(%p)", pollset);
230   g_event_engine->pollset_init(pollset, mu);
231 }
232 
pollset_shutdown(grpc_pollset * pollset,grpc_closure * closure)233 static void pollset_shutdown(grpc_pollset* pollset, grpc_closure* closure) {
234   GRPC_POLLING_API_TRACE("pollset_shutdown(%p)", pollset);
235   g_event_engine->pollset_shutdown(pollset, closure);
236 }
237 
pollset_destroy(grpc_pollset * pollset)238 static void pollset_destroy(grpc_pollset* pollset) {
239   GRPC_POLLING_API_TRACE("pollset_destroy(%p)", pollset);
240   g_event_engine->pollset_destroy(pollset);
241 }
242 
pollset_work(grpc_pollset * pollset,grpc_pollset_worker ** worker,grpc_core::Timestamp deadline)243 static grpc_error_handle pollset_work(grpc_pollset* pollset,
244                                       grpc_pollset_worker** worker,
245                                       grpc_core::Timestamp deadline) {
246   GRPC_POLLING_API_TRACE("pollset_work(%p, %" PRId64 ") begin", pollset,
247                          deadline.milliseconds_after_process_epoch());
248   grpc_error_handle err =
249       g_event_engine->pollset_work(pollset, worker, deadline);
250   GRPC_POLLING_API_TRACE("pollset_work(%p, %" PRId64 ") end", pollset,
251                          deadline.milliseconds_after_process_epoch());
252   return err;
253 }
254 
pollset_kick(grpc_pollset * pollset,grpc_pollset_worker * specific_worker)255 static grpc_error_handle pollset_kick(grpc_pollset* pollset,
256                                       grpc_pollset_worker* specific_worker) {
257   GRPC_POLLING_API_TRACE("pollset_kick(%p, %p)", pollset, specific_worker);
258   return g_event_engine->pollset_kick(pollset, specific_worker);
259 }
260 
grpc_pollset_add_fd(grpc_pollset * pollset,struct grpc_fd * fd)261 void grpc_pollset_add_fd(grpc_pollset* pollset, struct grpc_fd* fd) {
262   GRPC_POLLING_API_TRACE("pollset_add_fd(%p, %d)", pollset,
263                          grpc_fd_wrapped_fd(fd));
264   g_event_engine->pollset_add_fd(pollset, fd);
265 }
266 
pollset_global_init()267 void pollset_global_init() {}
pollset_global_shutdown()268 void pollset_global_shutdown() {}
269 
270 grpc_pollset_vtable grpc_posix_pollset_vtable = {
271     pollset_global_init, pollset_global_shutdown,
272     pollset_init,        pollset_shutdown,
273     pollset_destroy,     pollset_work,
274     pollset_kick,        pollset_size};
275 
pollset_set_create(void)276 static grpc_pollset_set* pollset_set_create(void) {
277   grpc_pollset_set* pss = g_event_engine->pollset_set_create();
278   GRPC_POLLING_API_TRACE("pollset_set_create(%p)", pss);
279   return pss;
280 }
281 
pollset_set_destroy(grpc_pollset_set * pollset_set)282 static void pollset_set_destroy(grpc_pollset_set* pollset_set) {
283   GRPC_POLLING_API_TRACE("pollset_set_destroy(%p)", pollset_set);
284   g_event_engine->pollset_set_destroy(pollset_set);
285 }
286 
pollset_set_add_pollset(grpc_pollset_set * pollset_set,grpc_pollset * pollset)287 static void pollset_set_add_pollset(grpc_pollset_set* pollset_set,
288                                     grpc_pollset* pollset) {
289   GRPC_POLLING_API_TRACE("pollset_set_add_pollset(%p, %p)", pollset_set,
290                          pollset);
291   g_event_engine->pollset_set_add_pollset(pollset_set, pollset);
292 }
293 
pollset_set_del_pollset(grpc_pollset_set * pollset_set,grpc_pollset * pollset)294 static void pollset_set_del_pollset(grpc_pollset_set* pollset_set,
295                                     grpc_pollset* pollset) {
296   GRPC_POLLING_API_TRACE("pollset_set_del_pollset(%p, %p)", pollset_set,
297                          pollset);
298   g_event_engine->pollset_set_del_pollset(pollset_set, pollset);
299 }
300 
pollset_set_add_pollset_set(grpc_pollset_set * bag,grpc_pollset_set * item)301 static void pollset_set_add_pollset_set(grpc_pollset_set* bag,
302                                         grpc_pollset_set* item) {
303   GRPC_POLLING_API_TRACE("pollset_set_add_pollset_set(%p, %p)", bag, item);
304   g_event_engine->pollset_set_add_pollset_set(bag, item);
305 }
306 
pollset_set_del_pollset_set(grpc_pollset_set * bag,grpc_pollset_set * item)307 static void pollset_set_del_pollset_set(grpc_pollset_set* bag,
308                                         grpc_pollset_set* item) {
309   GRPC_POLLING_API_TRACE("pollset_set_del_pollset_set(%p, %p)", bag, item);
310   g_event_engine->pollset_set_del_pollset_set(bag, item);
311 }
312 
313 grpc_pollset_set_vtable grpc_posix_pollset_set_vtable = {
314     pollset_set_create,          pollset_set_destroy,
315     pollset_set_add_pollset,     pollset_set_del_pollset,
316     pollset_set_add_pollset_set, pollset_set_del_pollset_set};
317 
grpc_pollset_set_add_fd(grpc_pollset_set * pollset_set,grpc_fd * fd)318 void grpc_pollset_set_add_fd(grpc_pollset_set* pollset_set, grpc_fd* fd) {
319   GRPC_POLLING_API_TRACE("pollset_set_add_fd(%p, %d)", pollset_set,
320                          grpc_fd_wrapped_fd(fd));
321   g_event_engine->pollset_set_add_fd(pollset_set, fd);
322 }
323 
grpc_pollset_set_del_fd(grpc_pollset_set * pollset_set,grpc_fd * fd)324 void grpc_pollset_set_del_fd(grpc_pollset_set* pollset_set, grpc_fd* fd) {
325   GRPC_POLLING_API_TRACE("pollset_set_del_fd(%p, %d)", pollset_set,
326                          grpc_fd_wrapped_fd(fd));
327   g_event_engine->pollset_set_del_fd(pollset_set, fd);
328 }
329 
grpc_is_any_background_poller_thread(void)330 bool grpc_is_any_background_poller_thread(void) {
331   return g_event_engine->is_any_background_poller_thread();
332 }
333 
grpc_add_closure_to_background_poller(grpc_closure * closure,grpc_error_handle error)334 bool grpc_add_closure_to_background_poller(grpc_closure* closure,
335                                            grpc_error_handle error) {
336   return g_event_engine->add_closure_to_background_poller(closure, error);
337 }
338 
grpc_shutdown_background_closure(void)339 void grpc_shutdown_background_closure(void) {
340   g_event_engine->shutdown_background_closure();
341 }
342 
343 #endif  // GRPC_POSIX_SOCKET_EV
344