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 #include <tevent_internal.h>
  23 #include "../lib/util/select.h"
  24
  25 /*
  26  * Return if there's something in the queue
  27  */
  28
  29 bool event_add_to_select_args(struct tevent_context *ev,
  30                               fd_set *read_fds, fd_set *write_fds,
  31                               struct timeval *timeout, int *maxfd)
  32 {
  33         struct timeval now;
  34         struct tevent_fd *fde;
  35         struct timeval diff;
  36         bool ret = false;
  37
  38         for (fde = ev->fd_events; fde; fde = fde->next) {
  39                 if (fde->flags & EVENT_FD_READ) {
  40                         FD_SET(fde->fd, read_fds);
  41                         ret = true;
  42                 }
  43                 if (fde->flags & EVENT_FD_WRITE) {
  44                         FD_SET(fde->fd, write_fds);
  45                         ret = true;
  46                 }
  47
  48                 if ((fde->flags & (EVENT_FD_READ|EVENT_FD_WRITE))
  49                     && (fde->fd > *maxfd)) {
  50                         *maxfd = fde->fd;
  51                 }
  52         }
  53
  54         if (ev->immediate_events != NULL) {
  55                 *timeout = timeval_zero();
  56                 return true;
  57         }
  58
  59         if (ev->timer_events == NULL) {
  60                 return ret;
  61         }
  62
  63         now = timeval_current();
  64         diff = timeval_until(&now, &ev->timer_events->next_event);
  65         *timeout = timeval_min(timeout, &diff);
  66
  67         return true;
  68 }
  69
  70 bool run_events(struct tevent_context *ev,
  71                 int selrtn, fd_set *read_fds, fd_set *write_fds)
  72 {
  73         struct tevent_fd *fde;
  74         struct timeval now;
  75
  76         if (ev->signal_events &&
  77             tevent_common_check_signal(ev)) {
  78                 return true;
  79         }
  80
  81         if (ev->immediate_events &&
  82             tevent_common_loop_immediate(ev)) {
  83                 return true;
  84         }
  85
  86         GetTimeOfDay(&now);
  87
  88         if ((ev->timer_events != NULL)
  89             && (timeval_compare(&now, &ev->timer_events->next_event) >= 0)) {
  90                 /* this older events system did not auto-free timed
  91                    events on running them, and had a race condition
  92                    where the event could be called twice if the
  93                    talloc_free of the te happened after the callback
  94                    made a call which invoked the event loop. To avoid
  95                    this while still allowing old code which frees the
  96                    te, we need to create a temporary context which
  97                    will be used to ensure the te is freed. We also
  98                    remove the te from the timed event list before we
  99                    call the handler, to ensure we can't loop */
 100
 101                 struct tevent_timer *te = ev->timer_events;
 102                 TALLOC_CTX *tmp_ctx = talloc_new(ev);
 103
 104                 DEBUG(10, ("Running timed event \"%s\" %p\n",
 105                            ev->timer_events->handler_name, ev->timer_events));
 106
 107                 DLIST_REMOVE(ev->timer_events, te);
 108                 talloc_steal(tmp_ctx, te);
 109
 110                 te->handler(ev, te, now, te->private_data);
 111
 112                 talloc_free(tmp_ctx);
 113                 return true;
 114         }
 115
 116         if (selrtn <= 0) {
 117                 /*
 118                  * No fd ready
 119                  */
 120                 return false;
 121         }
 122
 123         for (fde = ev->fd_events; fde; fde = fde->next) {
 124                 uint16 flags = 0;
 125
 126                 if (FD_ISSET(fde->fd, read_fds)) flags |= EVENT_FD_READ;
 127                 if (FD_ISSET(fde->fd, write_fds)) flags |= EVENT_FD_WRITE;
 128
 129                 if (flags & fde->flags) {
 130                         fde->handler(ev, fde, flags, fde->private_data);
 131                         return true;
 132                 }
 133         }
 134
 135         return false;
 136 }
 137
 138
 139 struct timeval *get_timed_events_timeout(struct tevent_context *ev,
 140                                          struct timeval *to_ret)
 141 {
 142         struct timeval now;
 143
 144         if ((ev->timer_events == NULL) && (ev->immediate_events == NULL)) {
 145                 return NULL;
 146         }
 147         if (ev->immediate_events != NULL) {
 148                 *to_ret = timeval_zero();
 149                 return to_ret;
 150         }
 151
 152         now = timeval_current();
 153         *to_ret = timeval_until(&now, &ev->timer_events->next_event);
 154
 155         DEBUG(10, ("timed_events_timeout: %d/%d\n", (int)to_ret->tv_sec,
 156                 (int)to_ret->tv_usec));
 157
 158         return to_ret;
 159 }
 160
 161 static int s3_event_loop_once(struct tevent_context *ev, const char *location)
 162 {
 163         struct timeval to;
 164         fd_set r_fds, w_fds;
 165         int maxfd = 0;
 166         int ret;
 167
 168         FD_ZERO(&r_fds);
 169         FD_ZERO(&w_fds);
 170
 171         to.tv_sec = 9999;       /* Max timeout */
 172         to.tv_usec = 0;
 173
 174         if (run_events(ev, 0, NULL, NULL)) {
 175                 return 0;
 176         }
 177
 178         if (!event_add_to_select_args(ev, &r_fds, &w_fds, &to, &maxfd)) {
 179                 return -1;
 180         }
 181
 182         ret = sys_select(maxfd+1, &r_fds, &w_fds, NULL, &to);
 183
 184         if (ret == -1 && errno != EINTR) {
 185                 tevent_debug(ev, TEVENT_DEBUG_FATAL,
 186                              "sys_select() failed: %d:%s\n",
 187                              errno, strerror(errno));
 188                 return -1;
 189         }
 190
 191         run_events(ev, ret, &r_fds, &w_fds);
 192         return 0;
 193 }
 194
 195 static int s3_event_context_init(struct tevent_context *ev)
 196 {
 197         return 0;
 198 }
 199
 200 void dump_event_list(struct tevent_context *ev)
 201 {
 202         struct tevent_timer *te;
 203         struct tevent_fd *fe;
 204         struct timeval evt, now;
 205
 206         if (!ev) {
 207                 return;
 208         }
 209
 210         now = timeval_current();
 211
 212         DEBUG(10,("dump_event_list:\n"));
 213
 214         for (te = ev->timer_events; te; te = te->next) {
 215
 216                 evt = timeval_until(&now, &te->next_event);
 217
 218                 DEBUGADD(10,("Timed Event \"%s\" %p handled in %d seconds (at %s)\n",
 219                            te->handler_name,
 220                            te,
 221                            (int)evt.tv_sec,
 222                            http_timestring(talloc_tos(), te->next_event.tv_sec)));
 223         }
 224
 225         for (fe = ev->fd_events; fe; fe = fe->next) {
 226
 227                 DEBUGADD(10,("FD Event %d %p, flags: 0x%04x\n",
 228                            fe->fd,
 229                            fe,
 230                            fe->flags));
 231         }
 232 }
 233
 234 static const struct tevent_ops s3_event_ops = {
 235         .context_init           = s3_event_context_init,
 236         .add_fd                 = tevent_common_add_fd,
 237         .set_fd_close_fn        = tevent_common_fd_set_close_fn,
 238         .get_fd_flags           = tevent_common_fd_get_flags,
 239         .set_fd_flags           = tevent_common_fd_set_flags,
 240         .add_timer              = tevent_common_add_timer,
 241         .schedule_immediate     = tevent_common_schedule_immediate,
 242         .add_signal             = tevent_common_add_signal,
 243         .loop_once              = s3_event_loop_once,
 244         .loop_wait              = tevent_common_loop_wait,
 245 };
 246
 247 static bool s3_tevent_init(void)
 248 {
 249         static bool initialized;
 250         if (initialized) {
 251                 return true;
 252         }
 253         initialized = tevent_register_backend("s3", &s3_event_ops);
 254         tevent_set_default_backend("s3");
 255         return initialized;
 256 }
 257
 258 /*
 259   this is used to catch debug messages from events
 260 */
 261 static void s3_event_debug(void *context, enum tevent_debug_level level,
 262                            const char *fmt, va_list ap)  PRINTF_ATTRIBUTE(3,0);
 263
 264 static void s3_event_debug(void *context, enum tevent_debug_level level,
 265                            const char *fmt, va_list ap)
 266 {
 267         int samba_level = -1;
 268         char *s = NULL;
 269         switch (level) {
 270         case TEVENT_DEBUG_FATAL:
 271                 samba_level = 0;
 272                 break;
 273         case TEVENT_DEBUG_ERROR:
 274                 samba_level = 1;
 275                 break;
 276         case TEVENT_DEBUG_WARNING:
 277                 samba_level = 2;
 278                 break;
 279         case TEVENT_DEBUG_TRACE:
 280                 samba_level = 11;
 281                 break;
 282
 283         };
 284         if (vasprintf(&s, fmt, ap) == -1) {
 285                 return;
 286         }
 287         DEBUG(samba_level, ("s3_event: %s", s));
 288         free(s);
 289 }
 290
 291 struct tevent_context *s3_tevent_context_init(TALLOC_CTX *mem_ctx)
 292 {
 293         struct tevent_context *ev;
 294
 295         s3_tevent_init();
 296
 297         ev = tevent_context_init_byname(mem_ctx, "s3");
 298         if (ev) {
 299                 tevent_set_debug(ev, s3_event_debug, NULL);
 300         }
 301
 302         return ev;
 303 }
 304