source/lib/events.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    Timed event library.
   4    Copyright (C) Andrew Tridgell 1992-1998
   5    Copyright (C) Volker Lendecke 2005
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  19 */
  20
  21 #include "includes.h"
  22
  23 struct timed_event {
  24         struct timed_event *next, *prev;
  25         struct event_context *event_ctx;
  26         struct timeval when;
  27         const char *event_name;
  28         void (*handler)(struct event_context *event_ctx,
  29                         struct timed_event *te,
  30                         const struct timeval *now,
  31                         void *private_data);
  32         void *private_data;
  33 };
  34
  35 struct fd_event {
  36         struct fd_event *prev, *next;
  37         struct event_context *event_ctx;
  38         int fd;
  39         uint16_t flags; /* see EVENT_FD_* flags */
  40         void (*handler)(struct event_context *event_ctx,
  41                         struct fd_event *event,
  42                         uint16 flags,
  43                         void *private_data);
  44         void *private_data;
  45 };
  46
  47 #define EVENT_FD_WRITEABLE(fde) \
  48         event_set_fd_flags(fde, event_get_fd_flags(fde) | EVENT_FD_WRITE)
  49 #define EVENT_FD_READABLE(fde) \
  50         event_set_fd_flags(fde, event_get_fd_flags(fde) | EVENT_FD_READ)
  51
  52 #define EVENT_FD_NOT_WRITEABLE(fde) \
  53         event_set_fd_flags(fde, event_get_fd_flags(fde) & ~EVENT_FD_WRITE)
  54 #define EVENT_FD_NOT_READABLE(fde) \
  55         event_set_fd_flags(fde, event_get_fd_flags(fde) & ~EVENT_FD_READ)
  56
  57 struct event_context {
  58         struct timed_event *timed_events;
  59         struct fd_event *fd_events;
  60 };
  61
  62 static int timed_event_destructor(struct timed_event *te)
  63 {
  64         DEBUG(10, ("Destroying timed event %lx \"%s\"\n", (unsigned long)te,
  65                 te->event_name));
  66         DLIST_REMOVE(te->event_ctx->timed_events, te);
  67         return 0;
  68 }
  69
  70 /****************************************************************************
  71  Add te by time.
  72 ****************************************************************************/
  73
  74 static void add_event_by_time(struct timed_event *te)
  75 {
  76         struct event_context *ctx = te->event_ctx;
  77         struct timed_event *last_te, *cur_te;
  78
  79         /* Keep the list ordered by time. We must preserve this. */
  80         last_te = NULL;
  81         for (cur_te = ctx->timed_events; cur_te; cur_te = cur_te->next) {
  82                 /* if the new event comes before the current one break */
  83                 if (!timeval_is_zero(&cur_te->when) &&
  84                                 timeval_compare(&te->when, &cur_te->when) < 0) {
  85                         break;
  86                 }
  87                 last_te = cur_te;
  88         }
  89
  90         DLIST_ADD_AFTER(ctx->timed_events, te, last_te);
  91 }
  92
  93 /****************************************************************************
  94  Schedule a function for future calling, cancel with TALLOC_FREE().
  95  It's the responsibility of the handler to call TALLOC_FREE() on the event
  96  handed to it.
  97 ****************************************************************************/
  98
  99 struct timed_event *event_add_timed(struct event_context *event_ctx,
 100                                 TALLOC_CTX *mem_ctx,
 101                                 struct timeval when,
 102                                 const char *event_name,
 103                                 void (*handler)(struct event_context *event_ctx,
 104                                                 struct timed_event *te,
 105                                                 const struct timeval *now,
 106                                                 void *private_data),
 107                                 void *private_data)
 108 {
 109         struct timed_event *te;
 110
 111         te = TALLOC_P(mem_ctx, struct timed_event);
 112         if (te == NULL) {
 113                 DEBUG(0, ("talloc failed\n"));
 114                 return NULL;
 115         }
 116
 117         te->event_ctx = event_ctx;
 118         te->when = when;
 119         te->event_name = event_name;
 120         te->handler = handler;
 121         te->private_data = private_data;
 122
 123         add_event_by_time(te);
 124
 125         talloc_set_destructor(te, timed_event_destructor);
 126
 127         DEBUG(10, ("Added timed event \"%s\": %lx\n", event_name,
 128                         (unsigned long)te));
 129         return te;
 130 }
 131
 132 static int fd_event_destructor(struct fd_event *fde)
 133 {
 134         struct event_context *event_ctx = fde->event_ctx;
 135
 136         DLIST_REMOVE(event_ctx->fd_events, fde);
 137         return 0;
 138 }
 139
 140 struct fd_event *event_add_fd(struct event_context *event_ctx,
 141                               TALLOC_CTX *mem_ctx,
 142                               int fd, uint16_t flags,
 143                               void (*handler)(struct event_context *event_ctx,
 144                                               struct fd_event *event,
 145                                               uint16 flags,
 146                                               void *private_data),
 147                               void *private_data)
 148 {
 149         struct fd_event *fde;
 150
 151         if (!(fde = TALLOC_P(mem_ctx, struct fd_event))) {
 152                 return NULL;
 153         }
 154
 155         fde->event_ctx = event_ctx;
 156         fde->fd = fd;
 157         fde->flags = flags;
 158         fde->handler = handler;
 159         fde->private_data = private_data;
 160
 161         DLIST_ADD(event_ctx->fd_events, fde);
 162
 163         talloc_set_destructor(fde, fd_event_destructor);
 164         return fde;
 165 }
 166
 167 void event_fd_set_writeable(struct fd_event *fde)
 168 {
 169         fde->flags |= EVENT_FD_WRITE;
 170 }
 171
 172 void event_fd_set_not_writeable(struct fd_event *fde)
 173 {
 174         fde->flags &= ~EVENT_FD_WRITE;
 175 }
 176
 177 void event_fd_set_readable(struct fd_event *fde)
 178 {
 179         fde->flags |= EVENT_FD_READ;
 180 }
 181
 182 void event_fd_set_not_readable(struct fd_event *fde)
 183 {
 184         fde->flags &= ~EVENT_FD_READ;
 185 }
 186
 187 /*
 188  * Return if there's something in the queue
 189  */
 190
 191 bool event_add_to_select_args(struct event_context *event_ctx,
 192                               const struct timeval *now,
 193                               fd_set *read_fds, fd_set *write_fds,
 194                               struct timeval *timeout, int *maxfd)
 195 {
 196         struct fd_event *fde;
 197         struct timeval diff;
 198         bool ret = False;
 199
 200         for (fde = event_ctx->fd_events; fde; fde = fde->next) {
 201                 if (fde->flags & EVENT_FD_READ) {
 202                         FD_SET(fde->fd, read_fds);
 203                         ret = True;
 204                 }
 205                 if (fde->flags & EVENT_FD_WRITE) {
 206                         FD_SET(fde->fd, write_fds);
 207                         ret = True;
 208                 }
 209
 210                 if ((fde->flags & (EVENT_FD_READ|EVENT_FD_WRITE))
 211                     && (fde->fd > *maxfd)) {
 212                         *maxfd = fde->fd;
 213                 }
 214         }
 215
 216         if (event_ctx->timed_events == NULL) {
 217                 return ret;
 218         }
 219
 220         diff = timeval_until(now, &event_ctx->timed_events->when);
 221         *timeout = timeval_min(timeout, &diff);
 222
 223         return True;
 224 }
 225
 226 bool events_pending(struct event_context *event_ctx)
 227 {
 228         struct fd_event *fde;
 229
 230         if (event_ctx->timed_events != NULL) {
 231                 return True;
 232         }
 233         for (fde = event_ctx->fd_events; fde; fde = fde->next) {
 234                 if (fde->flags & (EVENT_FD_READ|EVENT_FD_WRITE)) {
 235                         return True;
 236                 }
 237         }
 238         return False;
 239 }
 240
 241 bool run_events(struct event_context *event_ctx,
 242                 int selrtn, fd_set *read_fds, fd_set *write_fds)
 243 {
 244         bool fired = False;
 245         struct fd_event *fde, *next;
 246
 247         /* Run all events that are pending, not just one (as we
 248            did previously. */
 249
 250         while (event_ctx->timed_events) {
 251                 struct timeval now;
 252                 GetTimeOfDay(&now);
 253
 254                 if (timeval_compare(
 255                             &now, &event_ctx->timed_events->when) < 0) {
 256                         /* Nothing to do yet */
 257                         DEBUG(11, ("run_events: Nothing to do\n"));
 258                         break;
 259                 }
 260
 261                 DEBUG(10, ("Running event \"%s\" %lx\n",
 262                            event_ctx->timed_events->event_name,
 263                            (unsigned long)event_ctx->timed_events));
 264
 265                 event_ctx->timed_events->handler(
 266                         event_ctx,
 267                         event_ctx->timed_events, &now,
 268                         event_ctx->timed_events->private_data);
 269
 270                 fired = True;
 271         }
 272
 273         if (fired) {
 274                 /*
 275                  * We might have changed the socket status during the timed
 276                  * events, return to run select again.
 277                  */
 278                 return True;
 279         }
 280
 281         if (selrtn == 0) {
 282                 /*
 283                  * No fd ready
 284                  */
 285                 return fired;
 286         }
 287
 288         for (fde = event_ctx->fd_events; fde; fde = next) {
 289                 uint16 flags = 0;
 290
 291                 next = fde->next;
 292                 if (FD_ISSET(fde->fd, read_fds)) flags |= EVENT_FD_READ;
 293                 if (FD_ISSET(fde->fd, write_fds)) flags |= EVENT_FD_WRITE;
 294
 295                 if (flags) {
 296                         fde->handler(event_ctx, fde, flags, fde->private_data);
 297                         fired = True;
 298                 }
 299         }
 300
 301         return fired;
 302 }
 303
 304
 305 struct timeval *get_timed_events_timeout(struct event_context *event_ctx,
 306                                          struct timeval *to_ret)
 307 {
 308         struct timeval now;
 309
 310         if (event_ctx->timed_events == NULL) {
 311                 return NULL;
 312         }
 313
 314         now = timeval_current();
 315         *to_ret = timeval_until(&now, &event_ctx->timed_events->when);
 316
 317         DEBUG(10, ("timed_events_timeout: %d/%d\n", (int)to_ret->tv_sec,
 318                 (int)to_ret->tv_usec));
 319
 320         return to_ret;
 321 }
 322
 323 int event_loop_once(struct event_context *ev)
 324 {
 325         struct timeval now, to;
 326         fd_set r_fds, w_fds;
 327         int maxfd = 0;
 328         int ret;
 329
 330         FD_ZERO(&r_fds);
 331         FD_ZERO(&w_fds);
 332
 333         to.tv_sec = 9999;       /* Max timeout */
 334         to.tv_usec = 0;
 335
 336         GetTimeOfDay(&now);
 337
 338         if (!event_add_to_select_args(ev, &now, &r_fds, &w_fds, &to, &maxfd)) {
 339                 return -1;
 340         }
 341
 342         if (timeval_is_zero(&to)) {
 343                 run_events(ev, 0, NULL, NULL);
 344                 return 0;
 345         }
 346
 347         ret = sys_select(maxfd, &r_fds, &w_fds, NULL, &to);
 348
 349         if (ret == -1 && errno != EINTR) {
 350                 return -1;
 351         }
 352
 353         run_events(ev, ret, &r_fds, &w_fds);
 354         return 0;
 355 }
 356
 357 struct event_context *event_context_init(TALLOC_CTX *mem_ctx)
 358 {
 359         return TALLOC_ZERO_P(NULL, struct event_context);
 360 }
 361
 362 int set_event_dispatch_time(struct event_context *event_ctx,
 363                             const char *event_name, struct timeval when)
 364 {
 365         struct timed_event *te;
 366
 367         for (te = event_ctx->timed_events; te; te = te->next) {
 368                 if (strcmp(event_name, te->event_name) == 0) {
 369                         DLIST_REMOVE(event_ctx->timed_events, te);
 370                         te->when = when;
 371                         add_event_by_time(te);
 372                         return 1;
 373                 }
 374         }
 375         return 0;
 376 }
 377
 378 /* Returns 1 if event was found and cancelled, 0 otherwise. */
 379
 380 int cancel_named_event(struct event_context *event_ctx,
 381                        const char *event_name)
 382 {
 383         struct timed_event *te;
 384
 385         for (te = event_ctx->timed_events; te; te = te->next) {
 386                 if (strcmp(event_name, te->event_name) == 0) {
 387                         TALLOC_FREE(te);
 388                         return 1;
 389                 }
 390         }
 391         return 0;
 392 }
 393
 394 void dump_event_list(struct event_context *event_ctx)
 395 {
 396         struct timed_event *te;
 397         struct fd_event *fe;
 398         struct timeval evt, now;
 399
 400         if (!event_ctx) {
 401                 return;
 402         }
 403
 404         now = timeval_current();
 405
 406         DEBUG(10,("dump_event_list:\n"));
 407
 408         for (te = event_ctx->timed_events; te; te = te->next) {
 409
 410                 evt = timeval_until(&now, &te->when);
 411
 412                 DEBUGADD(10,("Timed Event \"%s\" %lx handled in %d seconds (at %s)\n",
 413                            te->event_name,
 414                            (unsigned long)te,
 415                            (int)evt.tv_sec,
 416                            http_timestring(te->when.tv_sec)));
 417         }
 418
 419         for (fe = event_ctx->fd_events; fe; fe = fe->next) {
 420
 421                 DEBUGADD(10,("FD Event %d %lx, flags: 0x%04x\n",
 422                            fe->fd,
 423                            (unsigned long)fe,
 424                            fe->flags));
 425         }
 426 }