main/autoservice.c

   1 /*
   2  * Asterisk -- An open source telephony toolkit.
   3  *
   4  * Copyright (C) 1999 - 2008, Digium, Inc.
   5  *
   6  * Mark Spencer <markster@digium.com>
   7  * Russell Bryant <russell@digium.com>
   8  *
   9  * See http://www.asterisk.org for more information about
  10  * the Asterisk project. Please do not directly contact
  11  * any of the maintainers of this project for assistance;
  12  * the project provides a web site, mailing lists and IRC
  13  * channels for your use.
  14  *
  15  * This program is free software, distributed under the terms of
  16  * the GNU General Public License Version 2. See the LICENSE file
  17  * at the top of the source tree.
  18  */
  19
  20 /*! \file
  21  *
  22  * \brief Automatic channel service routines
  23  *
  24  * \author Mark Spencer <markster@digium.com>
  25  * \author Russell Bryant <russell@digium.com>
  26  */
  27
  28 #include "asterisk.h"
  29
  30 ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
  31
  32 #include <stdio.h>
  33 #include <stdlib.h>
  34 #include <string.h>
  35 #include <sys/time.h>
  36 #include <signal.h>
  37 #include <errno.h>
  38 #include <unistd.h>
  39
  40 #include "asterisk/pbx.h"
  41 #include "asterisk/frame.h"
  42 #include "asterisk/sched.h"
  43 #include "asterisk/options.h"
  44 #include "asterisk/channel.h"
  45 #include "asterisk/logger.h"
  46 #include "asterisk/file.h"
  47 #include "asterisk/translate.h"
  48 #include "asterisk/manager.h"
  49 #include "asterisk/chanvars.h"
  50 #include "asterisk/linkedlists.h"
  51 #include "asterisk/indications.h"
  52 #include "asterisk/lock.h"
  53 #include "asterisk/utils.h"
  54
  55 #define MAX_AUTOMONS 1500
  56
  57 struct asent {
  58         struct ast_channel *chan;
  59         /*! This gets incremented each time autoservice gets started on the same
  60          *  channel.  It will ensure that it doesn't actually get stopped until
  61          *  it gets stopped for the last time. */
  62         unsigned int use_count;
  63         unsigned int orig_end_dtmf_flag:1;
  64         AST_LIST_HEAD_NOLOCK(, ast_frame) dtmf_frames;
  65         AST_LIST_ENTRY(asent) list;
  66 };
  67
  68 static AST_LIST_HEAD_STATIC(aslist, asent);
  69 static ast_cond_t as_cond;
  70
  71 static pthread_t asthread = AST_PTHREADT_NULL;
  72
  73 static int as_chan_list_state;
  74
  75 static void defer_frame(struct ast_channel *chan, struct ast_frame *f)
  76 {
  77         struct ast_frame *dup_f;
  78         struct asent *as;
  79
  80         AST_LIST_LOCK(&aslist);
  81         AST_LIST_TRAVERSE(&aslist, as, list) {
  82                 if (as->chan != chan)
  83                         continue;
  84                 if ((dup_f = ast_frdup(f)))
  85                         AST_LIST_INSERT_TAIL(&as->dtmf_frames, dup_f, frame_list);
  86         }
  87         AST_LIST_UNLOCK(&aslist);
  88 }
  89
  90 static void *autoservice_run(void *ign)
  91 {
  92         for (;;) {
  93                 struct ast_channel *mons[MAX_AUTOMONS];
  94                 struct ast_channel *chan;
  95                 struct asent *as;
  96                 int x = 0, ms = 500;
  97
  98                 AST_LIST_LOCK(&aslist);
  99
 100                 /* At this point, we know that no channels that have been removed are going
 101                  * to get used again. */
 102                 as_chan_list_state++;
 103
 104                 if (AST_LIST_EMPTY(&aslist))
 105                         ast_cond_wait(&as_cond, &aslist.lock);
 106
 107                 AST_LIST_TRAVERSE(&aslist, as, list) {
 108                         if (!as->chan->_softhangup) {
 109                                 if (x < MAX_AUTOMONS)
 110                                         mons[x++] = as->chan;
 111                                 else
 112                                         ast_log(LOG_WARNING, "Exceeded maximum number of automatic monitoring events.  Fix autoservice.c\n");
 113                         }
 114                 }
 115
 116                 AST_LIST_UNLOCK(&aslist);
 117
 118                 chan = ast_waitfor_n(mons, x, &ms);
 119                 if (chan) {
 120                         struct ast_frame *f = ast_read(chan);
 121
 122                         if (!f) {
 123                                 struct ast_frame hangup_frame = { 0, };
 124                                 /* No frame means the channel has been hung up.
 125                                  * A hangup frame needs to be queued here as ast_waitfor() may
 126                                  * never return again for the condition to be detected outside
 127                                  * of autoservice.  So, we'll leave a HANGUP queued up so the
 128                                  * thread in charge of this channel will know. */
 129
 130                                 hangup_frame.frametype = AST_FRAME_CONTROL;
 131                                 hangup_frame.subclass = AST_CONTROL_HANGUP;
 132
 133                                 defer_frame(chan, &hangup_frame);
 134
 135                                 continue;
 136                         }
 137
 138                         /* Do not add a default entry in this switch statement.  Each new
 139                          * frame type should be addressed directly as to whether it should
 140                          * be queued up or not. */
 141                         switch (f->frametype) {
 142                         /* Save these frames */
 143                         case AST_FRAME_DTMF_END:
 144                         case AST_FRAME_CONTROL:
 145                         case AST_FRAME_TEXT:
 146                         case AST_FRAME_IMAGE:
 147                         case AST_FRAME_HTML:
 148                                 defer_frame(chan, f);
 149                                 break;
 150
 151                         /* Throw these frames away */
 152                         case AST_FRAME_DTMF_BEGIN:
 153                         case AST_FRAME_VOICE:
 154                         case AST_FRAME_VIDEO:
 155                         case AST_FRAME_NULL:
 156                         case AST_FRAME_IAX:
 157                         case AST_FRAME_CNG:
 158                         case AST_FRAME_MODEM:
 159                                 break;
 160                         }
 161
 162                         if (f)
 163                                 ast_frfree(f);
 164                 }
 165         }
 166         asthread = AST_PTHREADT_NULL;
 167         return NULL;
 168 }
 169
 170 int ast_autoservice_start(struct ast_channel *chan)
 171 {
 172         int res = 0;
 173         struct asent *as;
 174
 175         /* Check if the channel already has autoservice */
 176         AST_LIST_LOCK(&aslist);
 177         AST_LIST_TRAVERSE(&aslist, as, list) {
 178                 if (as->chan == chan) {
 179                         as->use_count++;
 180                         break;
 181                 }
 182         }
 183         AST_LIST_UNLOCK(&aslist);
 184
 185         if (as) {
 186                 /* Entry exists, autoservice is already handling this channel */
 187                 return 0;
 188         }
 189
 190         if (!(as = ast_calloc(1, sizeof(*as))))
 191                 return -1;
 192
 193         /* New entry created */
 194         as->chan = chan;
 195         as->use_count = 1;
 196
 197         ast_channel_lock(chan);
 198         as->orig_end_dtmf_flag = ast_test_flag(chan, AST_FLAG_END_DTMF_ONLY) ? 1 : 0;
 199         if (!as->orig_end_dtmf_flag)
 200                 ast_set_flag(chan, AST_FLAG_END_DTMF_ONLY);
 201         ast_channel_unlock(chan);
 202
 203         AST_LIST_LOCK(&aslist);
 204         if (AST_LIST_EMPTY(&aslist))
 205                 ast_cond_signal(&as_cond);
 206         AST_LIST_INSERT_HEAD(&aslist, as, list);
 207         AST_LIST_UNLOCK(&aslist);
 208
 209         if (asthread == AST_PTHREADT_NULL) { /* need start the thread */
 210                 if (ast_pthread_create_background(&asthread, NULL, autoservice_run, NULL)) {
 211                         ast_log(LOG_WARNING, "Unable to create autoservice thread :(\n");
 212                         /* There will only be a single member in the list at this point,
 213                            the one we just added. */
 214                         AST_LIST_LOCK(&aslist);
 215                         AST_LIST_REMOVE(&aslist, as, list);
 216                         AST_LIST_UNLOCK(&aslist);
 217                         free(as);
 218                         res = -1;
 219                 } else
 220                         pthread_kill(asthread, SIGURG);
 221         }
 222
 223         return res;
 224 }
 225
 226 int ast_autoservice_stop(struct ast_channel *chan)
 227 {
 228         int res = -1;
 229         struct asent *as;
 230         AST_LIST_HEAD_NOLOCK(, ast_frame) dtmf_frames;
 231         struct ast_frame *f;
 232         int removed = 0;
 233         int orig_end_dtmf_flag = 0;
 234         int chan_list_state;
 235
 236         AST_LIST_HEAD_INIT_NOLOCK(&dtmf_frames);
 237
 238         AST_LIST_LOCK(&aslist);
 239
 240         /* Save the autoservice channel list state.  We _must_ verify that the channel
 241          * list has been rebuilt before we return.  Because, after we return, the channel
 242          * could get destroyed and we don't want our poor autoservice thread to step on
 243          * it after its gone! */
 244         chan_list_state = as_chan_list_state;
 245
 246         AST_LIST_TRAVERSE_SAFE_BEGIN(&aslist, as, list) {
 247                 if (as->chan == chan) {
 248                         as->use_count--;
 249                         if (as->use_count)
 250                                 break;
 251                         AST_LIST_REMOVE_CURRENT(&aslist, list);
 252                         AST_LIST_APPEND_LIST(&dtmf_frames, &as->dtmf_frames, frame_list);
 253                         orig_end_dtmf_flag = as->orig_end_dtmf_flag;
 254                         free(as);
 255                         removed = 1;
 256                         if (!chan->_softhangup)
 257                                 res = 0;
 258                         break;
 259                 }
 260         }
 261         AST_LIST_TRAVERSE_SAFE_END
 262
 263         if (removed && asthread != AST_PTHREADT_NULL)
 264                 pthread_kill(asthread, SIGURG);
 265
 266         AST_LIST_UNLOCK(&aslist);
 267
 268         if (!removed)
 269                 return 0;
 270
 271         if (!orig_end_dtmf_flag)
 272                 ast_clear_flag(chan, AST_FLAG_END_DTMF_ONLY);
 273
 274         /* Wait for it to un-block */
 275         while (ast_test_flag(chan, AST_FLAG_BLOCKING))
 276                 usleep(1000);
 277
 278         while ((f = AST_LIST_REMOVE_HEAD(&dtmf_frames, frame_list))) {
 279                 ast_queue_frame(chan, f);
 280                 ast_frfree(f);
 281         }
 282
 283         while (chan_list_state == as_chan_list_state)
 284                 usleep(1000);
 285
 286         return res;
 287 }
 288
 289 void ast_autoservice_init(void)
 290 {
 291         ast_cond_init(&as_cond, NULL);
 292 }