source3/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         if (te->event_ctx != NULL) {
  67                 DLIST_REMOVE(te->event_ctx->timed_events, te);
  68         }
  69         return 0;
  70 }
  71
  72 /****************************************************************************
  73  Add te by time.
  74 ****************************************************************************/
  75
  76 static void add_event_by_time(struct timed_event *te)
  77 {
  78         struct event_context *ctx = te->event_ctx;
  79         struct timed_event *last_te, *cur_te;
  80
  81         /* Keep the list ordered by time. We must preserve this. */
  82         last_te = NULL;
  83         for (cur_te = ctx->timed_events; cur_te; cur_te = cur_te->next) {
  84                 /* if the new event comes before the current one break */
  85                 if (!timeval_is_zero(&cur_te->when) &&
  86                                 timeval_compare(&te->when, &cur_te->when) < 0) {
  87                         break;
  88                 }
  89                 last_te = cur_te;
  90         }
  91
  92         DLIST_ADD_AFTER(ctx->timed_events, te, last_te);
  93 }
  94
  95 /****************************************************************************
  96  Schedule a function for future calling, cancel with TALLOC_FREE().
  97  It's the responsibility of the handler to call TALLOC_FREE() on the event
  98  handed to it.
  99 ****************************************************************************/
 100
 101 struct timed_event *event_add_timed(struct event_context *event_ctx,
 102                                 TALLOC_CTX *mem_ctx,
 103                                 struct timeval when,
 104                                 const char *event_name,
 105                                 void (*handler)(struct event_context *event_ctx,
 106                                                 struct timed_event *te,
 107                                                 const struct timeval *now,
 108                                                 void *private_data),
 109                                 void *private_data)
 110 {
 111         struct timed_event *te;
 112
 113         te = TALLOC_P(mem_ctx, struct timed_event);
 114         if (te == NULL) {
 115                 DEBUG(0, ("talloc failed\n"));
 116                 return NULL;
 117         }
 118
 119         te->event_ctx = event_ctx;
 120         te->when = when;
 121         te->event_name = event_name;
 122         te->handler = handler;
 123         te->private_data = private_data;
 124
 125         add_event_by_time(te);
 126
 127         talloc_set_destructor(te, timed_event_destructor);
 128
 129         DEBUG(10, ("Added timed event \"%s\": %lx\n", event_name,
 130                         (unsigned long)te));
 131         return te;
 132 }
 133
 134 static int fd_event_destructor(struct fd_event *fde)
 135 {
 136         if (fde->event_ctx != NULL) {
 137                 DLIST_REMOVE(fde->event_ctx->fd_events, fde);
 138         }
 139         return 0;
 140 }
 141
 142 struct fd_event *event_add_fd(struct event_context *event_ctx,
 143                               TALLOC_CTX *mem_ctx,
 144                               int fd, uint16_t flags,
 145                               void (*handler)(struct event_context *event_ctx,
 146                                               struct fd_event *event,
 147                                               uint16 flags,
 148                                               void *private_data),
 149                               void *private_data)
 150 {
 151         struct fd_event *fde;
 152
 153         if (!(fde = TALLOC_P(mem_ctx, struct fd_event))) {
 154                 return NULL;
 155         }
 156
 157         fde->event_ctx = event_ctx;
 158         fde->fd = fd;
 159         fde->flags = flags;
 160         fde->handler = handler;
 161         fde->private_data = private_data;
 162
 163         DLIST_ADD(event_ctx->fd_events, fde);
 164
 165         talloc_set_destructor(fde, fd_event_destructor);
 166         return fde;
 167 }
 168
 169 void event_fd_set_writeable(struct fd_event *fde)
 170 {
 171         fde->flags |= EVENT_FD_WRITE;
 172 }
 173
 174 void event_fd_set_not_writeable(struct fd_event *fde)
 175 {
 176         fde->flags &= ~EVENT_FD_WRITE;
 177 }
 178
 179 void event_fd_set_readable(struct fd_event *fde)
 180 {
 181         fde->flags |= EVENT_FD_READ;
 182 }
 183
 184 void event_fd_set_not_readable(struct fd_event *fde)
 185 {
 186         fde->flags &= ~EVENT_FD_READ;
 187 }
 188
 189 /*
 190  * Return if there's something in the queue
 191  */
 192
 193 bool event_add_to_select_args(struct event_context *event_ctx,
 194                               const struct timeval *now,
 195                               fd_set *read_fds, fd_set *write_fds,
 196                               struct timeval *timeout, int *maxfd)
 197 {
 198         struct fd_event *fde;
 199         struct timeval diff;
 200         bool ret = False;
 201
 202         for (fde = event_ctx->fd_events; fde; fde = fde->next) {
 203                 if (fde->flags & EVENT_FD_READ) {
 204                         FD_SET(fde->fd, read_fds);
 205                         ret = True;
 206                 }
 207                 if (fde->flags & EVENT_FD_WRITE) {
 208                         FD_SET(fde->fd, write_fds);
 209                         ret = True;
 210                 }
 211
 212                 if ((fde->flags & (EVENT_FD_READ|EVENT_FD_WRITE))
 213                     && (fde->fd > *maxfd)) {
 214                         *maxfd = fde->fd;
 215                 }
 216         }
 217
 218         if (event_ctx->timed_events == NULL) {
 219                 return ret;
 220         }
 221
 222         diff = timeval_until(now, &event_ctx->timed_events->when);
 223         *timeout = timeval_min(timeout, &diff);
 224
 225         return True;
 226 }
 227
 228 bool events_pending(struct event_context *event_ctx)
 229 {
 230         struct fd_event *fde;
 231
 232         if (event_ctx->timed_events != NULL) {
 233                 return True;
 234         }
 235         for (fde = event_ctx->fd_events; fde; fde = fde->next) {
 236                 if (fde->flags & (EVENT_FD_READ|EVENT_FD_WRITE)) {
 237                         return True;
 238                 }
 239         }
 240         return False;
 241 }
 242
 243 bool run_events(struct event_context *event_ctx,
 244                 int selrtn, fd_set *read_fds, fd_set *write_fds)
 245 {
 246         bool fired = False;
 247         struct fd_event *fde, *next;
 248
 249         /* Run all events that are pending, not just one (as we
 250            did previously. */
 251
 252         while (event_ctx->timed_events) {
 253                 struct timeval now;
 254                 GetTimeOfDay(&now);
 255
 256                 if (timeval_compare(
 257                             &now, &event_ctx->timed_events->when) < 0) {
 258                         /* Nothing to do yet */
 259                         DEBUG(11, ("run_events: Nothing to do\n"));
 260                         break;
 261                 }
 262
 263                 DEBUG(10, ("Running event \"%s\" %lx\n",
 264                            event_ctx->timed_events->event_name,
 265                            (unsigned long)event_ctx->timed_events));
 266
 267                 event_ctx->timed_events->handler(
 268                         event_ctx,
 269                         event_ctx->timed_events, &now,
 270                         event_ctx->timed_events->private_data);
 271
 272                 fired = True;
 273         }
 274
 275         if (fired) {
 276                 /*
 277                  * We might have changed the socket status during the timed
 278                  * events, return to run select again.
 279                  */
 280                 return True;
 281         }
 282
 283         if (selrtn == 0) {
 284                 /*
 285                  * No fd ready
 286                  */
 287                 return fired;
 288         }
 289
 290         for (fde = event_ctx->fd_events; fde; fde = next) {
 291                 uint16 flags = 0;
 292
 293                 next = fde->next;
 294                 if (FD_ISSET(fde->fd, read_fds)) flags |= EVENT_FD_READ;
 295                 if (FD_ISSET(fde->fd, write_fds)) flags |= EVENT_FD_WRITE;
 296
 297                 if (flags & fde->flags) {
 298                         fde->handler(event_ctx, fde, flags, fde->private_data);
 299                         fired = True;
 300                 }
 301         }
 302
 303         return fired;
 304 }
 305
 306
 307 struct timeval *get_timed_events_timeout(struct event_context *event_ctx,
 308                                          struct timeval *to_ret)
 309 {
 310         struct timeval now;
 311
 312         if (event_ctx->timed_events == NULL) {
 313                 return NULL;
 314         }
 315
 316         now = timeval_current();
 317         *to_ret = timeval_until(&now, &event_ctx->timed_events->when);
 318
 319         DEBUG(10, ("timed_events_timeout: %d/%d\n", (int)to_ret->tv_sec,
 320                 (int)to_ret->tv_usec));
 321
 322         return to_ret;
 323 }
 324
 325 int event_loop_once(struct event_context *ev)
 326 {
 327         struct timeval now, to;
 328         fd_set r_fds, w_fds;
 329         int maxfd = 0;
 330         int ret;
 331
 332         FD_ZERO(&r_fds);
 333         FD_ZERO(&w_fds);
 334
 335         to.tv_sec = 9999;       /* Max timeout */
 336         to.tv_usec = 0;
 337
 338         GetTimeOfDay(&now);
 339
 340         if (!event_add_to_select_args(ev, &now, &r_fds, &w_fds, &to, &maxfd)) {
 341                 return -1;
 342         }
 343
 344         if (timeval_is_zero(&to)) {
 345                 run_events(ev, 0, NULL, NULL);
 346                 return 0;
 347         }
 348
 349         ret = sys_select(maxfd+1, &r_fds, &w_fds, NULL, &to);
 350
 351         if (ret == -1 && errno != EINTR) {
 352                 return -1;
 353         }
 354
 355         run_events(ev, ret, &r_fds, &w_fds);
 356         return 0;
 357 }
 358
 359 static int event_context_destructor(struct event_context *ev)
 360 {
 361         while (ev->fd_events != NULL) {
 362                 ev->fd_events->event_ctx = NULL;
 363                 DLIST_REMOVE(ev->fd_events, ev->fd_events);
 364         }
 365         while (ev->timed_events != NULL) {
 366                 ev->timed_events->event_ctx = NULL;
 367                 DLIST_REMOVE(ev->timed_events, ev->timed_events);
 368         }
 369         return 0;
 370 }
 371
 372 struct event_context *event_context_init(TALLOC_CTX *mem_ctx)
 373 {
 374         struct event_context *result;
 375
 376         result = TALLOC_ZERO_P(mem_ctx, struct event_context);
 377         if (result == NULL) {
 378                 return NULL;
 379         }
 380
 381         talloc_set_destructor(result, event_context_destructor);
 382         return result;
 383 }
 384
 385 int set_event_dispatch_time(struct event_context *event_ctx,
 386                             const char *event_name, struct timeval when)
 387 {
 388         struct timed_event *te;
 389
 390         for (te = event_ctx->timed_events; te; te = te->next) {
 391                 if (strcmp(event_name, te->event_name) == 0) {
 392                         DLIST_REMOVE(event_ctx->timed_events, te);
 393                         te->when = when;
 394                         add_event_by_time(te);
 395                         return 1;
 396                 }
 397         }
 398         return 0;
 399 }
 400
 401 /* Returns 1 if event was found and cancelled, 0 otherwise. */
 402
 403 int cancel_named_event(struct event_context *event_ctx,
 404                        const char *event_name)
 405 {
 406         struct timed_event *te;
 407
 408         for (te = event_ctx->timed_events; te; te = te->next) {
 409                 if (strcmp(event_name, te->event_name) == 0) {
 410                         TALLOC_FREE(te);
 411                         return 1;
 412                 }
 413         }
 414         return 0;
 415 }
 416
 417 void dump_event_list(struct event_context *event_ctx)
 418 {
 419         struct timed_event *te;
 420         struct fd_event *fe;
 421         struct timeval evt, now;
 422
 423         if (!event_ctx) {
 424                 return;
 425         }
 426
 427         now = timeval_current();
 428
 429         DEBUG(10,("dump_event_list:\n"));
 430
 431         for (te = event_ctx->timed_events; te; te = te->next) {
 432
 433                 evt = timeval_until(&now, &te->when);
 434
 435                 DEBUGADD(10,("Timed Event \"%s\" %lx handled in %d seconds (at %s)\n",
 436                            te->event_name,
 437                            (unsigned long)te,
 438                            (int)evt.tv_sec,
 439                            http_timestring(te->when.tv_sec)));
 440         }
 441
 442         for (fe = event_ctx->fd_events; fe; fe = fe->next) {
 443
 444                 DEBUGADD(10,("FD Event %d %lx, flags: 0x%04x\n",
 445                            fe->fd,
 446                            (unsigned long)fe,
 447                            fe->flags));
 448         }
 449 }