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ngx_win32_select_module.c
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1 
2 /*
3  * Copyright (C) Igor Sysoev
4  * Copyright (C) Nginx, Inc.
5  */
6 
7 
8 #include <ngx_config.h>
9 #include <ngx_core.h>
10 #include <ngx_event.h>
11 
12 
13 static ngx_int_t ngx_select_init(ngx_cycle_t *cycle, ngx_msec_t timer);
14 static void ngx_select_done(ngx_cycle_t *cycle);
15 static ngx_int_t ngx_select_add_event(ngx_event_t *ev, ngx_int_t event,
16  ngx_uint_t flags);
17 static ngx_int_t ngx_select_del_event(ngx_event_t *ev, ngx_int_t event,
18  ngx_uint_t flags);
19 static ngx_int_t ngx_select_process_events(ngx_cycle_t *cycle, ngx_msec_t timer,
20  ngx_uint_t flags);
21 static void ngx_select_repair_fd_sets(ngx_cycle_t *cycle);
22 static char *ngx_select_init_conf(ngx_cycle_t *cycle, void *conf);
23 
24 
25 static fd_set master_read_fd_set;
26 static fd_set master_write_fd_set;
27 static fd_set work_read_fd_set;
28 static fd_set work_write_fd_set;
29 
30 static ngx_uint_t max_read;
31 static ngx_uint_t max_write;
32 static ngx_uint_t nevents;
33 
34 static ngx_event_t **event_index;
35 
36 
37 static ngx_str_t select_name = ngx_string("select");
38 
39 ngx_event_module_t ngx_select_module_ctx = {
40  &select_name,
41  NULL, /* create configuration */
42  ngx_select_init_conf, /* init configuration */
43 
44  {
45  ngx_select_add_event, /* add an event */
46  ngx_select_del_event, /* delete an event */
47  ngx_select_add_event, /* enable an event */
48  ngx_select_del_event, /* disable an event */
49  NULL, /* add an connection */
50  NULL, /* delete an connection */
51  NULL, /* process the changes */
52  ngx_select_process_events, /* process the events */
53  ngx_select_init, /* init the events */
54  ngx_select_done /* done the events */
55  }
56 
57 };
58 
59 ngx_module_t ngx_select_module = {
60  NGX_MODULE_V1,
61  &ngx_select_module_ctx, /* module context */
62  NULL, /* module directives */
63  NGX_EVENT_MODULE, /* module type */
64  NULL, /* init master */
65  NULL, /* init module */
66  NULL, /* init process */
67  NULL, /* init thread */
68  NULL, /* exit thread */
69  NULL, /* exit process */
70  NULL, /* exit master */
71  NGX_MODULE_V1_PADDING
72 };
73 
74 
75 static ngx_int_t
76 ngx_select_init(ngx_cycle_t *cycle, ngx_msec_t timer)
77 {
78  ngx_event_t **index;
79 
80  if (event_index == NULL) {
81  FD_ZERO(&master_read_fd_set);
82  FD_ZERO(&master_write_fd_set);
83  nevents = 0;
84  }
85 
86  if (ngx_process >= NGX_PROCESS_WORKER
87  || cycle->old_cycle == NULL
88  || cycle->old_cycle->connection_n < cycle->connection_n)
89  {
90  index = ngx_alloc(sizeof(ngx_event_t *) * 2 * cycle->connection_n,
91  cycle->log);
92  if (index == NULL) {
93  return NGX_ERROR;
94  }
95 
96  if (event_index) {
97  ngx_memcpy(index, event_index, sizeof(ngx_event_t *) * nevents);
98  ngx_free(event_index);
99  }
100 
101  event_index = index;
102  }
103 
104  ngx_io = ngx_os_io;
105 
106  ngx_event_actions = ngx_select_module_ctx.actions;
107 
108  ngx_event_flags = NGX_USE_LEVEL_EVENT;
109 
110  max_read = 0;
111  max_write = 0;
112 
113  return NGX_OK;
114 }
115 
116 
117 static void
118 ngx_select_done(ngx_cycle_t *cycle)
119 {
120  ngx_free(event_index);
121 
122  event_index = NULL;
123 }
124 
125 
126 static ngx_int_t
127 ngx_select_add_event(ngx_event_t *ev, ngx_int_t event, ngx_uint_t flags)
128 {
129  ngx_connection_t *c;
130 
131  c = ev->data;
132 
133  ngx_log_debug2(NGX_LOG_DEBUG_EVENT, ev->log, 0,
134  "select add event fd:%d ev:%i", c->fd, event);
135 
136  if (ev->index != NGX_INVALID_INDEX) {
137  ngx_log_error(NGX_LOG_ALERT, ev->log, 0,
138  "select event fd:%d ev:%i is already set", c->fd, event);
139  return NGX_OK;
140  }
141 
142  if ((event == NGX_READ_EVENT && ev->write)
143  || (event == NGX_WRITE_EVENT && !ev->write))
144  {
145  ngx_log_error(NGX_LOG_ALERT, ev->log, 0,
146  "invalid select %s event fd:%d ev:%i",
147  ev->write ? "write" : "read", c->fd, event);
148  return NGX_ERROR;
149  }
150 
151  if ((event == NGX_READ_EVENT) && (max_read >= FD_SETSIZE)
152  || (event == NGX_WRITE_EVENT) && (max_write >= FD_SETSIZE))
153  {
154  ngx_log_error(NGX_LOG_ERR, ev->log, 0,
155  "maximum number of descriptors "
156  "supported by select() is %d", FD_SETSIZE);
157  return NGX_ERROR;
158  }
159 
160  if (event == NGX_READ_EVENT) {
161  FD_SET(c->fd, &master_read_fd_set);
162  max_read++;
163 
164  } else if (event == NGX_WRITE_EVENT) {
165  FD_SET(c->fd, &master_write_fd_set);
166  max_write++;
167  }
168 
169  ev->active = 1;
170 
171  event_index[nevents] = ev;
172  ev->index = nevents;
173  nevents++;
174 
175  return NGX_OK;
176 }
177 
178 
179 static ngx_int_t
180 ngx_select_del_event(ngx_event_t *ev, ngx_int_t event, ngx_uint_t flags)
181 {
182  ngx_event_t *e;
183  ngx_connection_t *c;
184 
185  c = ev->data;
186 
187  ev->active = 0;
188 
189  if (ev->index == NGX_INVALID_INDEX) {
190  return NGX_OK;
191  }
192 
193  ngx_log_debug2(NGX_LOG_DEBUG_EVENT, ev->log, 0,
194  "select del event fd:%d ev:%i", c->fd, event);
195 
196  if (event == NGX_READ_EVENT) {
197  FD_CLR(c->fd, &master_read_fd_set);
198  max_read--;
199 
200  } else if (event == NGX_WRITE_EVENT) {
201  FD_CLR(c->fd, &master_write_fd_set);
202  max_write--;
203  }
204 
205  if (ev->index < --nevents) {
206  e = event_index[nevents];
207  event_index[ev->index] = e;
208  e->index = ev->index;
209  }
210 
211  ev->index = NGX_INVALID_INDEX;
212 
213  return NGX_OK;
214 }
215 
216 
217 static ngx_int_t
218 ngx_select_process_events(ngx_cycle_t *cycle, ngx_msec_t timer,
219  ngx_uint_t flags)
220 {
221  int ready, nready;
222  ngx_err_t err;
223  ngx_uint_t i, found;
224  ngx_event_t *ev, **queue;
225  struct timeval tv, *tp;
226  ngx_connection_t *c;
227 
228 #if (NGX_DEBUG)
229  if (cycle->log->log_level & NGX_LOG_DEBUG_ALL) {
230  for (i = 0; i < nevents; i++) {
231  ev = event_index[i];
232  c = ev->data;
233  ngx_log_debug2(NGX_LOG_DEBUG_EVENT, cycle->log, 0,
234  "select event: fd:%d wr:%d", c->fd, ev->write);
235  }
236  }
237 #endif
238 
239  if (timer == NGX_TIMER_INFINITE) {
240  tp = NULL;
241 
242  } else {
243  tv.tv_sec = (long) (timer / 1000);
244  tv.tv_usec = (long) ((timer % 1000) * 1000);
245  tp = &tv;
246  }
247 
248  ngx_log_debug1(NGX_LOG_DEBUG_EVENT, cycle->log, 0,
249  "select timer: %M", timer);
250 
251  work_read_fd_set = master_read_fd_set;
252  work_write_fd_set = master_write_fd_set;
253 
254  if (max_read || max_write) {
255  ready = select(0, &work_read_fd_set, &work_write_fd_set, NULL, tp);
256 
257  } else {
258 
259  /*
260  * Winsock select() requires that at least one descriptor set must be
261  * be non-null, and any non-null descriptor set must contain at least
262  * one handle to a socket. Otherwise select() returns WSAEINVAL.
263  */
264 
265  ngx_msleep(timer);
266 
267  ready = 0;
268  }
269 
270  err = (ready == -1) ? ngx_socket_errno : 0;
271 
272  if (flags & NGX_UPDATE_TIME) {
273  ngx_time_update();
274  }
275 
276  ngx_log_debug1(NGX_LOG_DEBUG_EVENT, cycle->log, 0,
277  "select ready %d", ready);
278 
279  if (err) {
280  ngx_log_error(NGX_LOG_ALERT, cycle->log, err, "select() failed");
281 
282  if (err == WSAENOTSOCK) {
283  ngx_select_repair_fd_sets(cycle);
284  }
285 
286  return NGX_ERROR;
287  }
288 
289  if (ready == 0) {
290  if (timer != NGX_TIMER_INFINITE) {
291  return NGX_OK;
292  }
293 
294  ngx_log_error(NGX_LOG_ALERT, cycle->log, 0,
295  "select() returned no events without timeout");
296  return NGX_ERROR;
297  }
298 
299  ngx_mutex_lock(ngx_posted_events_mutex);
300 
301  nready = 0;
302 
303  for (i = 0; i < nevents; i++) {
304  ev = event_index[i];
305  c = ev->data;
306  found = 0;
307 
308  if (ev->write) {
309  if (FD_ISSET(c->fd, &work_write_fd_set)) {
310  found = 1;
311  ngx_log_debug1(NGX_LOG_DEBUG_EVENT, cycle->log, 0,
312  "select write %d", c->fd);
313  }
314 
315  } else {
316  if (FD_ISSET(c->fd, &work_read_fd_set)) {
317  found = 1;
318  ngx_log_debug1(NGX_LOG_DEBUG_EVENT, cycle->log, 0,
319  "select read %d", c->fd);
320  }
321  }
322 
323  if (found) {
324  ev->ready = 1;
325 
326  queue = (ngx_event_t **) (ev->accept ? &ngx_posted_accept_events:
327  &ngx_posted_events);
328  ngx_locked_post_event(ev, queue);
329 
330  nready++;
331  }
332  }
333 
334  ngx_mutex_unlock(ngx_posted_events_mutex);
335 
336  if (ready != nready) {
337  ngx_log_error(NGX_LOG_ALERT, cycle->log, 0,
338  "select ready != events: %d:%d", ready, nready);
339 
340  ngx_select_repair_fd_sets(cycle);
341  }
342 
343  return NGX_OK;
344 }
345 
346 
347 static void
348 ngx_select_repair_fd_sets(ngx_cycle_t *cycle)
349 {
350  int n;
351  u_int i;
352  socklen_t len;
353  ngx_err_t err;
354  ngx_socket_t s;
355 
356  for (i = 0; i < master_read_fd_set.fd_count; i++) {
357 
358  s = master_read_fd_set.fd_array[i];
359  len = sizeof(int);
360 
361  if (getsockopt(s, SOL_SOCKET, SO_TYPE, (char *) &n, &len) == -1) {
362  err = ngx_socket_errno;
363 
364  ngx_log_error(NGX_LOG_ALERT, cycle->log, err,
365  "invalid descriptor #%d in read fd_set", s);
366 
367  FD_CLR(s, &master_read_fd_set);
368  }
369  }
370 
371  for (i = 0; i < master_write_fd_set.fd_count; i++) {
372 
373  s = master_write_fd_set.fd_array[i];
374  len = sizeof(int);
375 
376  if (getsockopt(s, SOL_SOCKET, SO_TYPE, (char *) &n, &len) == -1) {
377  err = ngx_socket_errno;
378 
379  ngx_log_error(NGX_LOG_ALERT, cycle->log, err,
380  "invalid descriptor #%d in write fd_set", s);
381 
382  FD_CLR(s, &master_write_fd_set);
383  }
384  }
385 }
386 
387 
388 static char *
389 ngx_select_init_conf(ngx_cycle_t *cycle, void *conf)
390 {
391  ngx_event_conf_t *ecf;
392 
393  ecf = ngx_event_get_conf(cycle->conf_ctx, ngx_event_core_module);
394 
395  if (ecf->use != ngx_select_module.ctx_index) {
396  return NGX_CONF_OK;
397  }
398 
399  return NGX_CONF_OK;
400 }
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