lib/pollfd.c

   1 /*
   2  * libwebsockets - small server side websockets and web server implementation
   3  *
   4  * Copyright (C) 2010-2015 Andy Green <andy@warmcat.com>
   5  *
   6  *  This library is free software; you can redistribute it and/or
   7  *  modify it under the terms of the GNU Lesser General Public
   8  *  License as published by the Free Software Foundation:
   9  *  version 2.1 of the License.
  10  *
  11  *  This library is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  *  Lesser General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU Lesser General Public
  17  *  License along with this library; if not, write to the Free Software
  18  *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
  19  *  MA  02110-1301  USA
  20  */
  21
  22 #include "private-libwebsockets.h"
  23
  24 int
  25 _lws_change_pollfd(struct lws *wsi, int _and, int _or, struct lws_pollargs *pa)
  26 {
  27         struct lws_context_per_thread *pt;
  28         struct lws_context *context;
  29         int ret = 0, pa_events = 1;
  30         struct lws_pollfd *pfd;
  31         int sampled_tid, tid;
  32
  33         if (!wsi || wsi->position_in_fds_table < 0)
  34                 return 0;
  35
  36         context = wsi->context;
  37         pt = &context->pt[(int)wsi->tsi];
  38         assert(wsi->position_in_fds_table >= 0 &&
  39                wsi->position_in_fds_table < pt->fds_count);
  40
  41         pfd = &pt->fds[wsi->position_in_fds_table];
  42         pa->fd = wsi->sock;
  43         pa->prev_events = pfd->events;
  44         pa->events = pfd->events = (pfd->events & ~_and) | _or;
  45
  46         //lwsl_notice("%s: wsi %p, posin %d. from %d -> %d\n", __func__, wsi, wsi->position_in_fds_table, pa->prev_events, pa->events);
  47
  48
  49         if (wsi->http2_substream)
  50                 return 0;
  51
  52         if (wsi->vhost->protocols[0].callback(wsi, LWS_CALLBACK_CHANGE_MODE_POLL_FD,
  53                                            wsi->user_space, (void *)pa, 0)) {
  54                 ret = -1;
  55                 goto bail;
  56         }
  57
  58         if (_and & LWS_POLLIN) {
  59                 lws_libev_io(wsi, LWS_EV_STOP | LWS_EV_READ);
  60                 lws_libuv_io(wsi, LWS_EV_STOP | LWS_EV_READ);
  61         }
  62         if (_or & LWS_POLLIN) {
  63                 lws_libev_io(wsi, LWS_EV_START | LWS_EV_READ);
  64                 lws_libuv_io(wsi, LWS_EV_START | LWS_EV_READ);
  65         }
  66         if (_and & LWS_POLLOUT) {
  67                 lws_libev_io(wsi, LWS_EV_STOP | LWS_EV_WRITE);
  68                 lws_libuv_io(wsi, LWS_EV_STOP | LWS_EV_WRITE);
  69         }
  70         if (_or & LWS_POLLOUT) {
  71                 lws_libev_io(wsi, LWS_EV_START | LWS_EV_WRITE);
  72                 lws_libuv_io(wsi, LWS_EV_START | LWS_EV_WRITE);
  73         }
  74
  75         /*
  76          * if we changed something in this pollfd...
  77          *   ... and we're running in a different thread context
  78          *     than the service thread...
  79          *       ... and the service thread is waiting ...
  80          *         then cancel it to force a restart with our changed events
  81          */
  82 #if LWS_POSIX
  83         pa_events = pa->prev_events != pa->events;
  84 #endif
  85
  86         if (pa_events) {
  87
  88                 if (lws_plat_change_pollfd(context, wsi, pfd)) {
  89                         lwsl_info("%s failed\n", __func__);
  90                         ret = -1;
  91                         goto bail;
  92                 }
  93
  94                 sampled_tid = context->service_tid;
  95                 if (sampled_tid) {
  96                         tid = wsi->vhost->protocols[0].callback(wsi,
  97                                      LWS_CALLBACK_GET_THREAD_ID, NULL, NULL, 0);
  98                         if (tid == -1) {
  99                                 ret = -1;
 100                                 goto bail;
 101                         }
 102                         if (tid != sampled_tid)
 103                                 lws_cancel_service_pt(wsi);
 104                 }
 105         }
 106 bail:
 107         return ret;
 108 }
 109
 110 #ifndef LWS_NO_SERVER
 111 static void
 112 lws_accept_modulation(struct lws_context_per_thread *pt, int allow)
 113 {
 114 // multithread listen seems broken
 115 #if 0
 116         struct lws_vhost *vh = context->vhost_list;
 117         struct lws_pollargs pa1;
 118
 119         while (vh) {
 120                 if (allow)
 121                         _lws_change_pollfd(pt->wsi_listening,
 122                                            0, LWS_POLLIN, &pa1);
 123                 else
 124                         _lws_change_pollfd(pt->wsi_listening,
 125                                            LWS_POLLIN, 0, &pa1);
 126                 vh = vh->vhost_next;
 127         }
 128 #endif
 129 }
 130 #endif
 131
 132 int
 133 insert_wsi_socket_into_fds(struct lws_context *context, struct lws *wsi)
 134 {
 135         struct lws_pollargs pa = { wsi->sock, LWS_POLLIN, 0 };
 136         struct lws_context_per_thread *pt = &context->pt[(int)wsi->tsi];
 137         int ret = 0;
 138
 139
 140         lwsl_debug("%s: %p: tsi=%d, sock=%d, pos-in-fds=%d\n",
 141                   __func__, wsi, wsi->tsi, wsi->sock, pt->fds_count);
 142
 143         if ((unsigned int)pt->fds_count >= context->fd_limit_per_thread) {
 144                 lwsl_err("Too many fds (%d vs %d)\n", context->max_fds,
 145                                 context->fd_limit_per_thread    );
 146                 return 1;
 147         }
 148
 149 #if !defined(_WIN32) && !defined(MBED_OPERATORS) && !defined(LWS_WITH_ESP8266)
 150         if (wsi->sock >= context->max_fds) {
 151                 lwsl_err("Socket fd %d is too high (%d)\n",
 152                          wsi->sock, context->max_fds);
 153                 return 1;
 154         }
 155 #endif
 156
 157         assert(wsi);
 158         assert(wsi->vhost);
 159         assert(lws_socket_is_valid(wsi->sock));
 160
 161         if (wsi->vhost->protocols[0].callback(wsi, LWS_CALLBACK_LOCK_POLL,
 162                                            wsi->user_space, (void *) &pa, 1))
 163                 return -1;
 164
 165         lws_pt_lock(pt);
 166         pt->count_conns++;
 167         insert_wsi(context, wsi);
 168 #if defined(LWS_WITH_ESP8266)
 169         if (wsi->position_in_fds_table == -1)
 170 #endif
 171                 wsi->position_in_fds_table = pt->fds_count;
 172
 173         // lwsl_notice("%s: %p: setting posinfds %d\n", __func__, wsi, wsi->position_in_fds_table);
 174
 175         pt->fds[wsi->position_in_fds_table].fd = wsi->sock;
 176 #if LWS_POSIX
 177         pt->fds[wsi->position_in_fds_table].events = LWS_POLLIN;
 178 #else
 179         pt->fds[wsi->position_in_fds_table].events = 0; // LWS_POLLIN;
 180 #endif
 181         pa.events = pt->fds[pt->fds_count].events;
 182
 183         lws_plat_insert_socket_into_fds(context, wsi);
 184
 185         /* external POLL support via protocol 0 */
 186         if (wsi->vhost->protocols[0].callback(wsi, LWS_CALLBACK_ADD_POLL_FD,
 187                                            wsi->user_space, (void *) &pa, 0))
 188                 ret =  -1;
 189 #ifndef LWS_NO_SERVER
 190         /* if no more room, defeat accepts on this thread */
 191         if ((unsigned int)pt->fds_count == context->fd_limit_per_thread - 1)
 192                 lws_accept_modulation(pt, 0);
 193 #endif
 194         lws_pt_unlock(pt);
 195
 196         if (wsi->vhost->protocols[0].callback(wsi, LWS_CALLBACK_UNLOCK_POLL,
 197                                            wsi->user_space, (void *)&pa, 1))
 198                 ret = -1;
 199
 200         return ret;
 201 }
 202
 203 int
 204 remove_wsi_socket_from_fds(struct lws *wsi)
 205 {
 206         struct lws_context *context = wsi->context;
 207         struct lws_pollargs pa = { wsi->sock, 0, 0 };
 208 #if !defined(LWS_WITH_ESP8266)
 209         struct lws_context_per_thread *pt = &context->pt[(int)wsi->tsi];
 210         struct lws *end_wsi;
 211         int v;
 212 #endif
 213         int m, ret = 0;
 214
 215 #if !defined(_WIN32) && !defined(MBED_OPERATORS) && !defined(LWS_WITH_ESP8266)
 216         if (wsi->sock > context->max_fds) {
 217                 lwsl_err("fd %d too high (%d)\n", wsi->sock, context->max_fds);
 218                 return 1;
 219         }
 220 #endif
 221
 222         if (wsi->vhost->protocols[0].callback(wsi, LWS_CALLBACK_LOCK_POLL,
 223                                            wsi->user_space, (void *)&pa, 1))
 224                 return -1;
 225
 226         /*
 227          * detach ourselves from vh protocol list if we're on one
 228          * A -> B -> C
 229          * A -> C , or, B -> C, or A -> B
 230          */
 231         lwsl_info("%s: removing same prot wsi %p\n", __func__, wsi);
 232         if (wsi->same_vh_protocol_prev) {
 233                 assert (*(wsi->same_vh_protocol_prev) == wsi);
 234                 lwsl_info("have prev %p, setting him to our next %p\n",
 235                          wsi->same_vh_protocol_prev,
 236                          wsi->same_vh_protocol_next);
 237
 238                 /* guy who pointed to us should point to our next */
 239                 *(wsi->same_vh_protocol_prev) = wsi->same_vh_protocol_next;
 240         } //else
 241                 //lwsl_err("null wsi->prev\n");
 242         /* our next should point back to our prev */
 243         if (wsi->same_vh_protocol_next) {
 244                 wsi->same_vh_protocol_next->same_vh_protocol_prev =
 245                                 wsi->same_vh_protocol_prev;
 246         } //else
 247                 //lwsl_err("null wsi->next\n");
 248
 249         wsi->same_vh_protocol_prev = NULL;
 250         wsi->same_vh_protocol_next = NULL;
 251
 252         /* the guy who is to be deleted's slot index in pt->fds */
 253         m = wsi->position_in_fds_table;
 254
 255 #if !defined(LWS_WITH_ESP8266)
 256         lws_libev_io(wsi, LWS_EV_STOP | LWS_EV_READ | LWS_EV_WRITE | LWS_EV_PREPARE_DELETION);
 257         lws_libuv_io(wsi, LWS_EV_STOP | LWS_EV_READ | LWS_EV_WRITE | LWS_EV_PREPARE_DELETION);
 258
 259         lws_pt_lock(pt);
 260
 261         lwsl_debug("%s: wsi=%p, sock=%d, fds pos=%d, end guy pos=%d, endfd=%d\n",
 262                   __func__, wsi, wsi->sock, wsi->position_in_fds_table,
 263                   pt->fds_count, pt->fds[pt->fds_count].fd);
 264
 265         /* have the last guy take up the now vacant slot */
 266         pt->fds[m] = pt->fds[pt->fds_count - 1];
 267 #endif
 268         /* this decrements pt->fds_count */
 269         lws_plat_delete_socket_from_fds(context, wsi, m);
 270 #if !defined(LWS_WITH_ESP8266)
 271         v = (int) pt->fds[m].fd;
 272         /* end guy's "position in fds table" is now the deletion guy's old one */
 273         end_wsi = wsi_from_fd(context, v);
 274         if (!end_wsi) {
 275                 lwsl_err("no wsi found for sock fd %d at pos %d, pt->fds_count=%d\n", (int)pt->fds[m].fd, m, pt->fds_count);
 276                 assert(0);
 277         } else
 278                 end_wsi->position_in_fds_table = m;
 279
 280         /* deletion guy's lws_lookup entry needs nuking */
 281         delete_from_fd(context, wsi->sock);
 282         /* removed wsi has no position any more */
 283         wsi->position_in_fds_table = -1;
 284
 285         /* remove also from external POLL support via protocol 0 */
 286         if (lws_socket_is_valid(wsi->sock))
 287                 if (wsi->vhost->protocols[0].callback(wsi, LWS_CALLBACK_DEL_POLL_FD,
 288                                                    wsi->user_space, (void *) &pa, 0))
 289                         ret = -1;
 290 #ifndef LWS_NO_SERVER
 291         if (!context->being_destroyed)
 292                 /* if this made some room, accept connects on this thread */
 293                 if ((unsigned int)pt->fds_count < context->fd_limit_per_thread - 1)
 294                         lws_accept_modulation(pt, 1);
 295 #endif
 296         lws_pt_unlock(pt);
 297
 298         if (wsi->vhost->protocols[0].callback(wsi, LWS_CALLBACK_UNLOCK_POLL,
 299                                            wsi->user_space, (void *) &pa, 1))
 300                 ret = -1;
 301 #endif
 302         return ret;
 303 }
 304
 305 int
 306 lws_change_pollfd(struct lws *wsi, int _and, int _or)
 307 {
 308         struct lws_context_per_thread *pt;
 309         struct lws_context *context;
 310         struct lws_pollargs pa;
 311         int ret = 0;
 312
 313         if (!wsi || !wsi->protocol || wsi->position_in_fds_table < 0)
 314                 return 1;
 315
 316         context = lws_get_context(wsi);
 317         if (!context)
 318                 return 1;
 319
 320         if (wsi->vhost->protocols[0].callback(wsi, LWS_CALLBACK_LOCK_POLL,
 321                                            wsi->user_space,  (void *) &pa, 0))
 322                 return -1;
 323
 324         pt = &context->pt[(int)wsi->tsi];
 325
 326         lws_pt_lock(pt);
 327         ret = _lws_change_pollfd(wsi, _and, _or, &pa);
 328         lws_pt_unlock(pt);
 329         if (wsi->vhost->protocols[0].callback(wsi, LWS_CALLBACK_UNLOCK_POLL,
 330                                            wsi->user_space, (void *) &pa, 0))
 331                 ret = -1;
 332
 333         return ret;
 334 }
 335
 336 LWS_VISIBLE int
 337 lws_callback_on_writable(struct lws *wsi)
 338 {
 339 #ifdef LWS_USE_HTTP2
 340         struct lws *network_wsi, *wsi2;
 341         int already;
 342 #endif
 343
 344         if (wsi->state == LWSS_SHUTDOWN)
 345                 return 0;
 346
 347         if (wsi->socket_is_permanently_unusable)
 348                 return 0;
 349
 350 #ifdef LWS_USE_HTTP2
 351         lwsl_info("%s: %p\n", __func__, wsi);
 352
 353         if (wsi->mode != LWSCM_HTTP2_SERVING)
 354                 goto network_sock;
 355
 356         if (wsi->u.http2.requested_POLLOUT) {
 357                 lwsl_info("already pending writable\n");
 358                 return 1;
 359         }
 360
 361         if (wsi->u.http2.tx_credit <= 0) {
 362                 /*
 363                  * other side is not able to cope with us sending
 364                  * anything so no matter if we have POLLOUT on our side.
 365                  *
 366                  * Delay waiting for our POLLOUT until peer indicates he has
 367                  * space for more using tx window command in http2 layer
 368                  */
 369                 lwsl_info("%s: %p: waiting_tx_credit (%d)\n", __func__, wsi,
 370                           wsi->u.http2.tx_credit);
 371                 wsi->u.http2.waiting_tx_credit = 1;
 372                 return 0;
 373         }
 374
 375         network_wsi = lws_http2_get_network_wsi(wsi);
 376         already = network_wsi->u.http2.requested_POLLOUT;
 377
 378         /* mark everybody above him as requesting pollout */
 379
 380         wsi2 = wsi;
 381         while (wsi2) {
 382                 wsi2->u.http2.requested_POLLOUT = 1;
 383                 lwsl_info("mark %p pending writable\n", wsi2);
 384                 wsi2 = wsi2->u.http2.parent_wsi;
 385         }
 386
 387         /* for network action, act only on the network wsi */
 388
 389         wsi = network_wsi;
 390         if (already)
 391                 return 1;
 392 network_sock:
 393 #endif
 394
 395         if (lws_ext_cb_active(wsi, LWS_EXT_CB_REQUEST_ON_WRITEABLE, NULL, 0))
 396                 return 1;
 397
 398         if (wsi->position_in_fds_table < 0) {
 399                 lwsl_err("%s: failed to find socket %d\n", __func__, wsi->sock);
 400                 return -1;
 401         }
 402
 403         if (lws_change_pollfd(wsi, 0, LWS_POLLOUT))
 404                 return -1;
 405
 406         return 1;
 407 }
 408
 409 LWS_VISIBLE int
 410 lws_callback_on_writable_all_protocol_vhost(const struct lws_vhost *vhost,
 411                                       const struct lws_protocols *protocol)
 412 {
 413         struct lws *wsi;
 414
 415         if (protocol < vhost->protocols ||
 416             protocol >= (vhost->protocols + vhost->count_protocols)) {
 417
 418                 lwsl_err("%s: protocol %p is not from vhost %p (%p - %p)\n",
 419                         __func__, protocol, vhost->protocols, vhost,
 420                         (vhost->protocols + vhost->count_protocols));
 421
 422                 return -1;
 423         }
 424
 425         wsi = vhost->same_vh_protocol_list[protocol - vhost->protocols];
 426         //lwsl_notice("%s: protocol %p, start wsi %p\n", __func__, protocol, wsi);
 427         while (wsi) {
 428                 //lwsl_notice("%s: protocol %p, this wsi %p (wsi->protocol=%p)\n",
 429                 //              __func__, protocol, wsi, wsi->protocol);
 430                 assert(wsi->protocol == protocol);
 431                 assert(*wsi->same_vh_protocol_prev == wsi);
 432                 if (wsi->same_vh_protocol_next) {
 433                 //      lwsl_err("my next says %p\n", wsi->same_vh_protocol_next);
 434                 //      lwsl_err("my next's prev says %p\n",
 435                 //              wsi->same_vh_protocol_next->same_vh_protocol_prev);
 436                         assert(wsi->same_vh_protocol_next->same_vh_protocol_prev == &wsi->same_vh_protocol_next);
 437                 }
 438                 //lwsl_notice("  apv: %p\n", wsi);
 439                 lws_callback_on_writable(wsi);
 440                 wsi = wsi->same_vh_protocol_next;
 441         }
 442
 443         return 0;
 444 }
 445
 446 LWS_VISIBLE int
 447 lws_callback_on_writable_all_protocol(const struct lws_context *context,
 448                                       const struct lws_protocols *protocol)
 449 {
 450         struct lws_vhost *vhost = context->vhost_list;
 451         int n;
 452
 453         while (vhost) {
 454                 for (n = 0; n < vhost->count_protocols; n++)
 455                         if (protocol->callback ==
 456                             vhost->protocols[n].callback &&
 457                             !strcmp(protocol->name, vhost->protocols[n].name))
 458                                 break;
 459                 if (n != vhost->count_protocols)
 460                         lws_callback_on_writable_all_protocol_vhost(
 461                                 vhost, &vhost->protocols[n]);
 462
 463                 vhost = vhost->vhost_next;
 464         }
 465
 466         return 0;
 467 }