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