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_SOCKET_EV
24
25 #include "src/core/lib/iomgr/ev_posix.h"
26
27 #include <string.h>
28
29 #include <grpc/support/alloc.h>
30 #include <grpc/support/log.h>
31 #include <grpc/support/string_util.h>
32
33 #include "src/core/lib/debug/trace.h"
34 #include "src/core/lib/gpr/useful.h"
35 #include "src/core/lib/gprpp/global_config.h"
36 #include "src/core/lib/iomgr/ev_epoll1_linux.h"
37 #include "src/core/lib/iomgr/ev_epollex_linux.h"
38 #include "src/core/lib/iomgr/ev_poll_posix.h"
39 #include "src/core/lib/iomgr/internal_errqueue.h"
40
41 GPR_GLOBAL_CONFIG_DEFINE_STRING(
42 grpc_poll_strategy, "all",
43 "Declares which polling engines to try when starting gRPC. "
44 "This is a comma-separated list of engines, which are tried in priority "
45 "order first -> last.")
46
47 grpc_core::DebugOnlyTraceFlag grpc_polling_trace(
48 false, "polling"); /* Disabled by default */
49
50 /* Traces fd create/close operations */
51 grpc_core::DebugOnlyTraceFlag grpc_fd_trace(false, "fd_trace");
52 grpc_core::DebugOnlyTraceFlag grpc_trace_fd_refcount(false, "fd_refcount");
53 grpc_core::DebugOnlyTraceFlag grpc_polling_api_trace(false, "polling_api");
54
55 // Polling API trace only enabled in debug builds
56 #ifndef NDEBUG
57 #define GRPC_POLLING_API_TRACE(format, ...) \
58 if (GRPC_TRACE_FLAG_ENABLED(grpc_polling_api_trace)) { \
59 gpr_log(GPR_INFO, "(polling-api) " format, __VA_ARGS__); \
60 }
61 #else
62 #define GRPC_POLLING_API_TRACE(...)
63 #endif // NDEBUG
64
65 /** Default poll() function - a pointer so that it can be overridden by some
66 * tests */
67 #ifndef GPR_AIX
68 grpc_poll_function_type grpc_poll_function = poll;
69 #else
aix_poll(struct pollfd fds[],nfds_t nfds,int timeout)70 int aix_poll(struct pollfd fds[], nfds_t nfds, int timeout) {
71 return poll(fds, nfds, timeout);
72 }
73 grpc_poll_function_type grpc_poll_function = aix_poll;
74 #endif // GPR_AIX
75
76 grpc_wakeup_fd grpc_global_wakeup_fd;
77
78 static const grpc_event_engine_vtable* g_event_engine = nullptr;
79 static const char* g_poll_strategy_name = nullptr;
80
81 typedef const grpc_event_engine_vtable* (*event_engine_factory_fn)(
82 bool explicit_request);
83
84 typedef struct {
85 const char* name;
86 event_engine_factory_fn factory;
87 } event_engine_factory;
88
89 namespace {
90
91 grpc_poll_function_type real_poll_function;
92
dummy_poll(struct pollfd fds[],nfds_t nfds,int timeout)93 int dummy_poll(struct pollfd fds[], nfds_t nfds, int timeout) {
94 if (timeout == 0) {
95 return real_poll_function(fds, nfds, 0);
96 } else {
97 gpr_log(GPR_ERROR, "Attempted a blocking poll when declared non-polling.");
98 GPR_ASSERT(false);
99 return -1;
100 }
101 }
102
init_non_polling(bool explicit_request)103 const grpc_event_engine_vtable* init_non_polling(bool explicit_request) {
104 if (!explicit_request) {
105 return nullptr;
106 }
107 // return the simplest engine as a dummy but also override the poller
108 auto ret = grpc_init_poll_posix(explicit_request);
109 real_poll_function = grpc_poll_function;
110 grpc_poll_function = dummy_poll;
111
112 return ret;
113 }
114 } // namespace
115
116 #define ENGINE_HEAD_CUSTOM "head_custom"
117 #define ENGINE_TAIL_CUSTOM "tail_custom"
118
119 // The global array of event-engine factories. Each entry is a pair with a name
120 // and an event-engine generator function (nullptr if there is no generator
121 // registered for this name). The middle entries are the engines predefined by
122 // open-source gRPC. The head entries represent an opportunity for specific
123 // high-priority custom pollers to be added by the initializer plugins of
124 // custom-built gRPC libraries. The tail entries represent the same, but for
125 // low-priority custom pollers. The actual poller selected is either the first
126 // available one in the list if no specific poller is requested, or the first
127 // specific poller that is requested by name in the GRPC_POLL_STRATEGY
128 // environment variable if that variable is set (which should be a
129 // comma-separated list of one or more event engine names)
130 static event_engine_factory g_factories[] = {
131 {ENGINE_HEAD_CUSTOM, nullptr}, {ENGINE_HEAD_CUSTOM, nullptr},
132 {ENGINE_HEAD_CUSTOM, nullptr}, {ENGINE_HEAD_CUSTOM, nullptr},
133 {"epollex", grpc_init_epollex_linux}, {"epoll1", grpc_init_epoll1_linux},
134 {"poll", grpc_init_poll_posix}, {"none", init_non_polling},
135 {ENGINE_TAIL_CUSTOM, nullptr}, {ENGINE_TAIL_CUSTOM, nullptr},
136 {ENGINE_TAIL_CUSTOM, nullptr}, {ENGINE_TAIL_CUSTOM, nullptr},
137 };
138
add(const char * beg,const char * end,char *** ss,size_t * ns)139 static void add(const char* beg, const char* end, char*** ss, size_t* ns) {
140 size_t n = *ns;
141 size_t np = n + 1;
142 char* s;
143 size_t len;
144 GPR_ASSERT(end >= beg);
145 len = static_cast<size_t>(end - beg);
146 s = static_cast<char*>(gpr_malloc(len + 1));
147 memcpy(s, beg, len);
148 s[len] = 0;
149 *ss = static_cast<char**>(gpr_realloc(*ss, sizeof(char**) * np));
150 (*ss)[n] = s;
151 *ns = np;
152 }
153
split(const char * s,char *** ss,size_t * ns)154 static void split(const char* s, char*** ss, size_t* ns) {
155 const char* c = strchr(s, ',');
156 if (c == nullptr) {
157 add(s, s + strlen(s), ss, ns);
158 } else {
159 add(s, c, ss, ns);
160 split(c + 1, ss, ns);
161 }
162 }
163
is(const char * want,const char * have)164 static bool is(const char* want, const char* have) {
165 return 0 == strcmp(want, "all") || 0 == strcmp(want, have);
166 }
167
try_engine(const char * engine)168 static void try_engine(const char* engine) {
169 for (size_t i = 0; i < GPR_ARRAY_SIZE(g_factories); i++) {
170 if (g_factories[i].factory != nullptr && is(engine, g_factories[i].name)) {
171 if ((g_event_engine = g_factories[i].factory(
172 0 == strcmp(engine, g_factories[i].name)))) {
173 g_poll_strategy_name = g_factories[i].name;
174 gpr_log(GPR_DEBUG, "Using polling engine: %s", g_factories[i].name);
175 return;
176 }
177 }
178 }
179 }
180
181 /* Call this before calling grpc_event_engine_init() */
grpc_register_event_engine_factory(const char * name,event_engine_factory_fn factory,bool add_at_head)182 void grpc_register_event_engine_factory(const char* name,
183 event_engine_factory_fn factory,
184 bool add_at_head) {
185 const char* custom_match =
186 add_at_head ? ENGINE_HEAD_CUSTOM : ENGINE_TAIL_CUSTOM;
187
188 // Overwrite an existing registration if already registered
189 for (size_t i = 0; i < GPR_ARRAY_SIZE(g_factories); i++) {
190 if (0 == strcmp(name, g_factories[i].name)) {
191 g_factories[i].factory = factory;
192 return;
193 }
194 }
195
196 // Otherwise fill in an available custom slot
197 for (size_t i = 0; i < GPR_ARRAY_SIZE(g_factories); i++) {
198 if (0 == strcmp(g_factories[i].name, custom_match)) {
199 g_factories[i].name = name;
200 g_factories[i].factory = factory;
201 return;
202 }
203 }
204
205 // Otherwise fail
206 GPR_ASSERT(false);
207 }
208
209 /*If grpc_event_engine_init() has been called, returns the poll_strategy_name.
210 * Otherwise, returns nullptr. */
grpc_get_poll_strategy_name()211 const char* grpc_get_poll_strategy_name() { return g_poll_strategy_name; }
212
grpc_event_engine_init(void)213 void grpc_event_engine_init(void) {
214 grpc_core::UniquePtr<char> value = GPR_GLOBAL_CONFIG_GET(grpc_poll_strategy);
215
216 char** strings = nullptr;
217 size_t nstrings = 0;
218 split(value.get(), &strings, &nstrings);
219
220 for (size_t i = 0; g_event_engine == nullptr && i < nstrings; i++) {
221 try_engine(strings[i]);
222 }
223
224 for (size_t i = 0; i < nstrings; i++) {
225 gpr_free(strings[i]);
226 }
227 gpr_free(strings);
228
229 if (g_event_engine == nullptr) {
230 gpr_log(GPR_ERROR, "No event engine could be initialized from %s",
231 value.get());
232 abort();
233 }
234 }
235
grpc_event_engine_shutdown(void)236 void grpc_event_engine_shutdown(void) {
237 g_event_engine->shutdown_engine();
238 g_event_engine = nullptr;
239 }
240
grpc_event_engine_can_track_errors(void)241 bool grpc_event_engine_can_track_errors(void) {
242 /* Only track errors if platform supports errqueue. */
243 if (grpc_core::kernel_supports_errqueue()) {
244 return g_event_engine->can_track_err;
245 }
246 return false;
247 }
248
grpc_event_engine_run_in_background(void)249 bool grpc_event_engine_run_in_background(void) {
250 // g_event_engine is nullptr when using a custom iomgr.
251 return g_event_engine != nullptr && g_event_engine->run_in_background;
252 }
253
grpc_fd_create(int fd,const char * name,bool track_err)254 grpc_fd* grpc_fd_create(int fd, const char* name, bool track_err) {
255 GRPC_POLLING_API_TRACE("fd_create(%d, %s, %d)", fd, name, track_err);
256 GRPC_FD_TRACE("fd_create(%d, %s, %d)", fd, name, track_err);
257 return g_event_engine->fd_create(
258 fd, name, track_err && grpc_event_engine_can_track_errors());
259 }
260
grpc_fd_wrapped_fd(grpc_fd * fd)261 int grpc_fd_wrapped_fd(grpc_fd* fd) {
262 return g_event_engine->fd_wrapped_fd(fd);
263 }
264
grpc_fd_orphan(grpc_fd * fd,grpc_closure * on_done,int * release_fd,const char * reason)265 void grpc_fd_orphan(grpc_fd* fd, grpc_closure* on_done, int* release_fd,
266 const char* reason) {
267 GRPC_POLLING_API_TRACE("fd_orphan(%d, %p, %p, %s)", grpc_fd_wrapped_fd(fd),
268 on_done, release_fd, reason);
269 GRPC_FD_TRACE("grpc_fd_orphan, fd:%d closed", grpc_fd_wrapped_fd(fd));
270
271 g_event_engine->fd_orphan(fd, on_done, release_fd, reason);
272 }
273
grpc_fd_shutdown(grpc_fd * fd,grpc_error * why)274 void grpc_fd_shutdown(grpc_fd* fd, grpc_error* why) {
275 GRPC_POLLING_API_TRACE("fd_shutdown(%d)", grpc_fd_wrapped_fd(fd));
276 GRPC_FD_TRACE("fd_shutdown(%d)", grpc_fd_wrapped_fd(fd));
277 g_event_engine->fd_shutdown(fd, why);
278 }
279
grpc_fd_is_shutdown(grpc_fd * fd)280 bool grpc_fd_is_shutdown(grpc_fd* fd) {
281 return g_event_engine->fd_is_shutdown(fd);
282 }
283
grpc_fd_notify_on_read(grpc_fd * fd,grpc_closure * closure)284 void grpc_fd_notify_on_read(grpc_fd* fd, grpc_closure* closure) {
285 g_event_engine->fd_notify_on_read(fd, closure);
286 }
287
grpc_fd_notify_on_write(grpc_fd * fd,grpc_closure * closure)288 void grpc_fd_notify_on_write(grpc_fd* fd, grpc_closure* closure) {
289 g_event_engine->fd_notify_on_write(fd, closure);
290 }
291
grpc_fd_notify_on_error(grpc_fd * fd,grpc_closure * closure)292 void grpc_fd_notify_on_error(grpc_fd* fd, grpc_closure* closure) {
293 g_event_engine->fd_notify_on_error(fd, closure);
294 }
295
grpc_fd_set_readable(grpc_fd * fd)296 void grpc_fd_set_readable(grpc_fd* fd) { g_event_engine->fd_set_readable(fd); }
297
grpc_fd_set_writable(grpc_fd * fd)298 void grpc_fd_set_writable(grpc_fd* fd) { g_event_engine->fd_set_writable(fd); }
299
grpc_fd_set_error(grpc_fd * fd)300 void grpc_fd_set_error(grpc_fd* fd) { g_event_engine->fd_set_error(fd); }
301
pollset_size(void)302 static size_t pollset_size(void) { return g_event_engine->pollset_size; }
303
pollset_init(grpc_pollset * pollset,gpr_mu ** mu)304 static void pollset_init(grpc_pollset* pollset, gpr_mu** mu) {
305 GRPC_POLLING_API_TRACE("pollset_init(%p)", pollset);
306 g_event_engine->pollset_init(pollset, mu);
307 }
308
pollset_shutdown(grpc_pollset * pollset,grpc_closure * closure)309 static void pollset_shutdown(grpc_pollset* pollset, grpc_closure* closure) {
310 GRPC_POLLING_API_TRACE("pollset_shutdown(%p)", pollset);
311 g_event_engine->pollset_shutdown(pollset, closure);
312 }
313
pollset_destroy(grpc_pollset * pollset)314 static void pollset_destroy(grpc_pollset* pollset) {
315 GRPC_POLLING_API_TRACE("pollset_destroy(%p)", pollset);
316 g_event_engine->pollset_destroy(pollset);
317 }
318
pollset_work(grpc_pollset * pollset,grpc_pollset_worker ** worker,grpc_millis deadline)319 static grpc_error* pollset_work(grpc_pollset* pollset,
320 grpc_pollset_worker** worker,
321 grpc_millis deadline) {
322 GRPC_POLLING_API_TRACE("pollset_work(%p, %" PRId64 ") begin", pollset,
323 deadline);
324 grpc_error* err = g_event_engine->pollset_work(pollset, worker, deadline);
325 GRPC_POLLING_API_TRACE("pollset_work(%p, %" PRId64 ") end", pollset,
326 deadline);
327 return err;
328 }
329
pollset_kick(grpc_pollset * pollset,grpc_pollset_worker * specific_worker)330 static grpc_error* pollset_kick(grpc_pollset* pollset,
331 grpc_pollset_worker* specific_worker) {
332 GRPC_POLLING_API_TRACE("pollset_kick(%p, %p)", pollset, specific_worker);
333 return g_event_engine->pollset_kick(pollset, specific_worker);
334 }
335
grpc_pollset_add_fd(grpc_pollset * pollset,struct grpc_fd * fd)336 void grpc_pollset_add_fd(grpc_pollset* pollset, struct grpc_fd* fd) {
337 GRPC_POLLING_API_TRACE("pollset_add_fd(%p, %d)", pollset,
338 grpc_fd_wrapped_fd(fd));
339 g_event_engine->pollset_add_fd(pollset, fd);
340 }
341
pollset_global_init()342 void pollset_global_init() {}
pollset_global_shutdown()343 void pollset_global_shutdown() {}
344
345 grpc_pollset_vtable grpc_posix_pollset_vtable = {
346 pollset_global_init, pollset_global_shutdown,
347 pollset_init, pollset_shutdown,
348 pollset_destroy, pollset_work,
349 pollset_kick, pollset_size};
350
pollset_set_create(void)351 static grpc_pollset_set* pollset_set_create(void) {
352 grpc_pollset_set* pss = g_event_engine->pollset_set_create();
353 GRPC_POLLING_API_TRACE("pollset_set_create(%p)", pss);
354 return pss;
355 }
356
pollset_set_destroy(grpc_pollset_set * pollset_set)357 static void pollset_set_destroy(grpc_pollset_set* pollset_set) {
358 GRPC_POLLING_API_TRACE("pollset_set_destroy(%p)", pollset_set);
359 g_event_engine->pollset_set_destroy(pollset_set);
360 }
361
pollset_set_add_pollset(grpc_pollset_set * pollset_set,grpc_pollset * pollset)362 static void pollset_set_add_pollset(grpc_pollset_set* pollset_set,
363 grpc_pollset* pollset) {
364 GRPC_POLLING_API_TRACE("pollset_set_add_pollset(%p, %p)", pollset_set,
365 pollset);
366 g_event_engine->pollset_set_add_pollset(pollset_set, pollset);
367 }
368
pollset_set_del_pollset(grpc_pollset_set * pollset_set,grpc_pollset * pollset)369 static void pollset_set_del_pollset(grpc_pollset_set* pollset_set,
370 grpc_pollset* pollset) {
371 GRPC_POLLING_API_TRACE("pollset_set_del_pollset(%p, %p)", pollset_set,
372 pollset);
373 g_event_engine->pollset_set_del_pollset(pollset_set, pollset);
374 }
375
pollset_set_add_pollset_set(grpc_pollset_set * bag,grpc_pollset_set * item)376 static void pollset_set_add_pollset_set(grpc_pollset_set* bag,
377 grpc_pollset_set* item) {
378 GRPC_POLLING_API_TRACE("pollset_set_add_pollset_set(%p, %p)", bag, item);
379 g_event_engine->pollset_set_add_pollset_set(bag, item);
380 }
381
pollset_set_del_pollset_set(grpc_pollset_set * bag,grpc_pollset_set * item)382 static void pollset_set_del_pollset_set(grpc_pollset_set* bag,
383 grpc_pollset_set* item) {
384 GRPC_POLLING_API_TRACE("pollset_set_del_pollset_set(%p, %p)", bag, item);
385 g_event_engine->pollset_set_del_pollset_set(bag, item);
386 }
387
388 grpc_pollset_set_vtable grpc_posix_pollset_set_vtable = {
389 pollset_set_create, pollset_set_destroy,
390 pollset_set_add_pollset, pollset_set_del_pollset,
391 pollset_set_add_pollset_set, pollset_set_del_pollset_set};
392
grpc_pollset_set_add_fd(grpc_pollset_set * pollset_set,grpc_fd * fd)393 void grpc_pollset_set_add_fd(grpc_pollset_set* pollset_set, grpc_fd* fd) {
394 GRPC_POLLING_API_TRACE("pollset_set_add_fd(%p, %d)", pollset_set,
395 grpc_fd_wrapped_fd(fd));
396 g_event_engine->pollset_set_add_fd(pollset_set, fd);
397 }
398
grpc_pollset_set_del_fd(grpc_pollset_set * pollset_set,grpc_fd * fd)399 void grpc_pollset_set_del_fd(grpc_pollset_set* pollset_set, grpc_fd* fd) {
400 GRPC_POLLING_API_TRACE("pollset_set_del_fd(%p, %d)", pollset_set,
401 grpc_fd_wrapped_fd(fd));
402 g_event_engine->pollset_set_del_fd(pollset_set, fd);
403 }
404
grpc_is_any_background_poller_thread(void)405 bool grpc_is_any_background_poller_thread(void) {
406 return g_event_engine->is_any_background_poller_thread();
407 }
408
grpc_add_closure_to_background_poller(grpc_closure * closure,grpc_error * error)409 bool grpc_add_closure_to_background_poller(grpc_closure* closure,
410 grpc_error* error) {
411 return g_event_engine->add_closure_to_background_poller(closure, error);
412 }
413
grpc_shutdown_background_closure(void)414 void grpc_shutdown_background_closure(void) {
415 g_event_engine->shutdown_background_closure();
416 }
417
418 #endif // GRPC_POSIX_SOCKET_EV
419