nginx/src/event/modules/ngx_select_module.c

   1
   2 /*
   3  * Copyright (C) Igor Sysoev
   4  */
   5
   6
   7 #include <ngx_config.h>
   8 #include <ngx_core.h>
   9 #include <ngx_event.h>
  10
  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 char *ngx_select_init_conf(ngx_cycle_t *cycle, void *conf);
  22
  23
  24 static fd_set         master_read_fd_set;
  25 static fd_set         master_write_fd_set;
  26 static fd_set         work_read_fd_set;
  27 static fd_set         work_write_fd_set;
  28
  29 #if (NGX_WIN32)
  30 static ngx_uint_t     max_read;
  31 static ngx_uint_t     max_write;
  32 #else
  33 static ngx_int_t      max_fd;
  34 #endif
  35
  36 static ngx_uint_t     nevents;
  37
  38 static ngx_event_t  **event_index;
  39
  40
  41 static ngx_str_t    select_name = ngx_string("select");
  42
  43 ngx_event_module_t  ngx_select_module_ctx = {
  44     &select_name,
  45     NULL,                                  /* create configuration */
  46     ngx_select_init_conf,                  /* init configuration */
  47
  48     {
  49         ngx_select_add_event,              /* add an event */
  50         ngx_select_del_event,              /* delete an event */
  51         ngx_select_add_event,              /* enable an event */
  52         ngx_select_del_event,              /* disable an event */
  53         NULL,                              /* add an connection */
  54         NULL,                              /* delete an connection */
  55         NULL,                              /* process the changes */
  56         ngx_select_process_events,         /* process the events */
  57         ngx_select_init,                   /* init the events */
  58         ngx_select_done                    /* done the events */
  59     }
  60
  61 };
  62
  63 ngx_module_t  ngx_select_module = {
  64     NGX_MODULE_V1,
  65     &ngx_select_module_ctx,                /* module context */
  66     NULL,                                  /* module directives */
  67     NGX_EVENT_MODULE,                      /* module type */
  68     NULL,                                  /* init master */
  69     NULL,                                  /* init module */
  70     NULL,                                  /* init process */
  71     NULL,                                  /* init thread */
  72     NULL,                                  /* exit thread */
  73     NULL,                                  /* exit process */
  74     NULL,                                  /* exit master */
  75     NGX_MODULE_V1_PADDING
  76 };
  77
  78
  79 static ngx_int_t
  80 ngx_select_init(ngx_cycle_t *cycle, ngx_msec_t timer)
  81 {
  82     ngx_event_t  **index;
  83
  84     if (event_index == NULL) {
  85         FD_ZERO(&master_read_fd_set);
  86         FD_ZERO(&master_write_fd_set);
  87         nevents = 0;
  88     }
  89
  90     if (ngx_process == NGX_PROCESS_WORKER
  91         || cycle->old_cycle == NULL
  92         || cycle->old_cycle->connection_n < cycle->connection_n)
  93     {
  94         index = ngx_alloc(sizeof(ngx_event_t *) * 2 * cycle->connection_n,
  95                           cycle->log);
  96         if (index == NULL) {
  97             return NGX_ERROR;
  98         }
  99
 100         if (event_index) {
 101             ngx_memcpy(index, event_index, sizeof(ngx_event_t *) * nevents);
 102             ngx_free(event_index);
 103         }
 104
 105         event_index = index;
 106     }
 107
 108     ngx_io = ngx_os_io;
 109
 110     ngx_event_actions = ngx_select_module_ctx.actions;
 111
 112     ngx_event_flags = NGX_USE_LEVEL_EVENT;
 113
 114 #if (NGX_WIN32)
 115     max_read = max_write = 0;
 116 #else
 117     max_fd = -1;
 118 #endif
 119
 120     return NGX_OK;
 121 }
 122
 123
 124 static void
 125 ngx_select_done(ngx_cycle_t *cycle)
 126 {
 127     ngx_free(event_index);
 128
 129     event_index = NULL;
 130 }
 131
 132
 133 static ngx_int_t
 134 ngx_select_add_event(ngx_event_t *ev, ngx_int_t event, ngx_uint_t flags)
 135 {
 136     ngx_connection_t  *c;
 137
 138     c = ev->data;
 139
 140     ngx_log_debug2(NGX_LOG_DEBUG_EVENT, ev->log, 0,
 141                    "select add event fd:%d ev:%i", c->fd, event);
 142
 143     if (ev->index != NGX_INVALID_INDEX) {
 144         ngx_log_error(NGX_LOG_ALERT, ev->log, 0,
 145                       "select event fd:%d ev:%i is already set", c->fd, event);
 146         return NGX_OK;
 147     }
 148
 149 #if (NGX_WIN32)
 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 #else
 170
 171     if (event == NGX_READ_EVENT) {
 172         FD_SET(c->fd, &master_read_fd_set);
 173
 174     } else if (event == NGX_WRITE_EVENT) {
 175         FD_SET(c->fd, &master_write_fd_set);
 176     }
 177
 178     if (max_fd != -1 && max_fd < c->fd) {
 179         max_fd = c->fd;
 180     }
 181
 182 #endif
 183
 184     ev->active = 1;
 185
 186     event_index[nevents] = ev;
 187     ev->index = nevents;
 188     nevents++;
 189
 190     return NGX_OK;
 191 }
 192
 193
 194 static ngx_int_t
 195 ngx_select_del_event(ngx_event_t *ev, ngx_int_t event, ngx_uint_t flags)
 196 {
 197     ngx_connection_t  *c;
 198
 199     c = ev->data;
 200
 201     ev->active = 0;
 202
 203     if (ev->index == NGX_INVALID_INDEX) {
 204         return NGX_OK;
 205     }
 206
 207     ngx_log_debug2(NGX_LOG_DEBUG_EVENT, ev->log, 0,
 208                    "select del event fd:%d ev:%i", c->fd, event);
 209
 210 #if (NGX_WIN32)
 211
 212     if (event == NGX_READ_EVENT) {
 213         FD_CLR(c->fd, &master_read_fd_set);
 214         max_read--;
 215
 216     } else if (event == NGX_WRITE_EVENT) {
 217         FD_CLR(c->fd, &master_write_fd_set);
 218         max_write--;
 219     }
 220
 221 #else
 222
 223     if (event == NGX_READ_EVENT) {
 224         FD_CLR(c->fd, &master_read_fd_set);
 225
 226     } else if (event == NGX_WRITE_EVENT) {
 227         FD_CLR(c->fd, &master_write_fd_set);
 228     }
 229
 230     if (max_fd == c->fd) {
 231         max_fd = -1;
 232     }
 233
 234 #endif
 235
 236     if (ev->index < --nevents) {
 237         event_index[ev->index] = event_index[nevents];
 238         event_index[ev->index]->index = ev->index;
 239     }
 240
 241     ev->index = NGX_INVALID_INDEX;
 242
 243     return NGX_OK;
 244 }
 245
 246
 247 static ngx_int_t
 248 ngx_select_process_events(ngx_cycle_t *cycle, ngx_msec_t timer,
 249     ngx_uint_t flags)
 250 {
 251     int                 ready, nready;
 252     ngx_uint_t          i, found;
 253     ngx_err_t           err;
 254     ngx_event_t        *ev, **queue;
 255     ngx_connection_t   *c;
 256     struct timeval      tv, *tp;
 257
 258 #if !(NGX_WIN32)
 259
 260     if (max_fd == -1) {
 261         for (i = 0; i < nevents; i++) {
 262             c = event_index[i]->data;
 263             if (max_fd < c->fd) {
 264                 max_fd = c->fd;
 265             }
 266         }
 267
 268         ngx_log_debug1(NGX_LOG_DEBUG_EVENT, cycle->log, 0,
 269                        "change max_fd: %d", max_fd);
 270     }
 271
 272 #endif
 273
 274 #if (NGX_DEBUG)
 275     if (cycle->log->log_level & NGX_LOG_DEBUG_ALL) {
 276         for (i = 0; i < nevents; i++) {
 277             ev = event_index[i];
 278             c = ev->data;
 279             ngx_log_debug2(NGX_LOG_DEBUG_EVENT, cycle->log, 0,
 280                            "select event: fd:%d wr:%d", c->fd, ev->write);
 281         }
 282
 283 #if !(NGX_WIN32)
 284         ngx_log_debug1(NGX_LOG_DEBUG_EVENT, cycle->log, 0,
 285                        "max_fd: %d", max_fd);
 286 #endif
 287     }
 288 #endif
 289
 290     if (timer == NGX_TIMER_INFINITE) {
 291         tp = NULL;
 292
 293     } else {
 294         tv.tv_sec = (long) (timer / 1000);
 295         tv.tv_usec = (long) ((timer % 1000) * 1000);
 296         tp = &tv;
 297     }
 298
 299     ngx_log_debug1(NGX_LOG_DEBUG_EVENT, cycle->log, 0,
 300                    "select timer: %M", timer);
 301
 302     work_read_fd_set = master_read_fd_set;
 303     work_write_fd_set = master_write_fd_set;
 304
 305 #if 1
 306     ngx_log_debug1(NGX_LOG_DEBUG_EVENT, cycle->log, 0,
 307                    /*
 308                     * (void *) disables "dereferencing type-punned
 309                     * pointer will break strict-aliasing rules
 310                     */
 311                    "select read fd_set: %08Xd",
 312                    *(int *) (void *) &work_read_fd_set);
 313 #endif
 314
 315 #if (NGX_WIN32)
 316
 317     ready = select(0, &work_read_fd_set, &work_write_fd_set, NULL, tp);
 318
 319 #else
 320
 321     ready = select(max_fd + 1, &work_read_fd_set, &work_write_fd_set, NULL, tp);
 322
 323 #endif
 324
 325     if (ready == -1) {
 326         err = ngx_socket_errno;
 327     } else {
 328         err = 0;
 329     }
 330
 331     if (flags & NGX_UPDATE_TIME) {
 332         ngx_time_update(0, 0);
 333     }
 334
 335     ngx_log_debug1(NGX_LOG_DEBUG_EVENT, cycle->log, 0,
 336                    "select ready %d", ready);
 337
 338 #if (NGX_WIN32)
 339
 340     if (err) {
 341         ngx_log_error(NGX_LOG_ALERT, cycle->log, err, "select() failed");
 342         return NGX_ERROR;
 343     }
 344
 345 #else
 346
 347     if (err) {
 348         ngx_uint_t  level;
 349
 350         if (err == NGX_EINTR) {
 351
 352             if (ngx_event_timer_alarm) {
 353                 ngx_event_timer_alarm = 0;
 354                 return NGX_OK;
 355             }
 356
 357             level = NGX_LOG_INFO;
 358
 359         } else {
 360             level = NGX_LOG_ALERT;
 361         }
 362
 363         ngx_log_error(level, cycle->log, err, "select() failed");
 364         return NGX_ERROR;
 365     }
 366
 367 #endif
 368
 369     if (ready == 0) {
 370         if (timer != NGX_TIMER_INFINITE) {
 371             return NGX_OK;
 372         }
 373
 374         ngx_log_error(NGX_LOG_ALERT, cycle->log, 0,
 375                       "select() returned no events without timeout");
 376         return NGX_ERROR;
 377     }
 378
 379     ngx_mutex_lock(ngx_posted_events_mutex);
 380
 381     nready = 0;
 382
 383     for (i = 0; i < nevents; i++) {
 384         ev = event_index[i];
 385         c = ev->data;
 386         found = 0;
 387
 388         if (ev->write) {
 389             if (FD_ISSET(c->fd, &work_write_fd_set)) {
 390                 found = 1;
 391                 ngx_log_debug1(NGX_LOG_DEBUG_EVENT, cycle->log, 0,
 392                                "select write %d", c->fd);
 393             }
 394
 395         } else {
 396             if (FD_ISSET(c->fd, &work_read_fd_set)) {
 397                 found = 1;
 398                 ngx_log_debug1(NGX_LOG_DEBUG_EVENT, cycle->log, 0,
 399                                "select read %d", c->fd);
 400             }
 401         }
 402
 403         if (found) {
 404             ev->ready = 1;
 405
 406             queue = (ngx_event_t **) (ev->accept ? &ngx_posted_accept_events:
 407                                                    &ngx_posted_events);
 408             ngx_locked_post_event(ev, queue);
 409
 410             nready++;
 411         }
 412     }
 413
 414     ngx_mutex_unlock(ngx_posted_events_mutex);
 415
 416     if (ready != nready) {
 417         ngx_log_error(NGX_LOG_ALERT, cycle->log, 0, "select ready != events");
 418     }
 419
 420     return NGX_OK;
 421 }
 422
 423
 424 static char *
 425 ngx_select_init_conf(ngx_cycle_t *cycle, void *conf)
 426 {
 427     ngx_event_conf_t  *ecf;
 428
 429     ecf = ngx_event_get_conf(cycle->conf_ctx, ngx_event_core_module);
 430
 431     if (ecf->use != ngx_select_module.ctx_index) {
 432         return NGX_CONF_OK;
 433     }
 434
 435     /* disable warning: the default FD_SETSIZE is 1024U in FreeBSD 5.x */
 436
 437 #if !(NGX_WIN32)
 438
 439     if (cycle->connection_n > FD_SETSIZE) {
 440         ngx_log_error(NGX_LOG_EMERG, cycle->log, 0,
 441                       "the maximum number of files "
 442                       "supported by select() is %ud", FD_SETSIZE);
 443         return NGX_CONF_ERROR;
 444     }
 445
 446 #endif
 447
 448 #if (NGX_THREADS) && !(NGX_WIN32)
 449
 450     ngx_log_error(NGX_LOG_EMERG, cycle->log, 0,
 451                   "select() is not supported in the threaded mode");
 452     return NGX_CONF_ERROR;
 453
 454 #else
 455
 456     return NGX_CONF_OK;
 457
 458 #endif
 459 }