main/devicestate.c

   1 /*
   2  * Asterisk -- An open source telephony toolkit.
   3  *
   4  * Copyright (C) 1999 - 2006, Digium, Inc.
   5  *
   6  * Mark Spencer <markster@digium.com>
   7  *
   8  * See http://www.asterisk.org for more information about
   9  * the Asterisk project. Please do not directly contact
  10  * any of the maintainers of this project for assistance;
  11  * the project provides a web site, mailing lists and IRC
  12  * channels for your use.
  13  *
  14  * This program is free software, distributed under the terms of
  15  * the GNU General Public License Version 2. See the LICENSE file
  16  * at the top of the source tree.
  17  */
  18
  19 /*! \file
  20  *
  21  * \brief Device state management
  22  *
  23  * \author Mark Spencer <markster@digium.com>
  24  */
  25
  26 #include "asterisk.h"
  27
  28 ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
  29
  30 #include <sys/types.h>
  31 #include <unistd.h>
  32 #include <stdlib.h>
  33 #include <string.h>
  34 #include <stdio.h>
  35
  36 #include "asterisk/channel.h"
  37 #include "asterisk/utils.h"
  38 #include "asterisk/lock.h"
  39 #include "asterisk/linkedlists.h"
  40 #include "asterisk/logger.h"
  41 #include "asterisk/devicestate.h"
  42 #include "asterisk/pbx.h"
  43 #include "asterisk/app.h"
  44 #include "asterisk/options.h"
  45
  46 /*! \brief Device state strings for printing */
  47 static const char *devstatestring[] = {
  48         /* 0 AST_DEVICE_UNKNOWN */      "Unknown",      /*!< Valid, but unknown state */
  49         /* 1 AST_DEVICE_NOT_INUSE */    "Not in use",   /*!< Not used */
  50         /* 2 AST_DEVICE IN USE */       "In use",       /*!< In use */
  51         /* 3 AST_DEVICE_BUSY */         "Busy",         /*!< Busy */
  52         /* 4 AST_DEVICE_INVALID */      "Invalid",      /*!< Invalid - not known to Asterisk */
  53         /* 5 AST_DEVICE_UNAVAILABLE */  "Unavailable",  /*!< Unavailable (not registred) */
  54         /* 6 AST_DEVICE_RINGING */      "Ringing",      /*!< Ring, ring, ring */
  55         /* 7 AST_DEVICE_RINGINUSE */    "Ring+Inuse",   /*!< Ring and in use */
  56         /* 8 AST_DEVICE_ONHOLD */       "On Hold"       /*!< On Hold */
  57 };
  58
  59 /*! \brief  A device state provider (not a channel) */
  60 struct devstate_prov {
  61         char label[40];
  62         ast_devstate_prov_cb_type callback;
  63         AST_LIST_ENTRY(devstate_prov) list;
  64 };
  65
  66 /*! \brief A list of providers */
  67 static AST_LIST_HEAD_STATIC(devstate_provs, devstate_prov);
  68
  69 /*! \brief  A device state watcher (callback) */
  70 struct devstate_cb {
  71         void *data;
  72         ast_devstate_cb_type callback;
  73         AST_LIST_ENTRY(devstate_cb) list;
  74 };
  75
  76 /*! \brief A device state watcher list */
  77 static AST_LIST_HEAD_STATIC(devstate_cbs, devstate_cb);
  78
  79 struct state_change {
  80         AST_LIST_ENTRY(state_change) list;
  81         char device[1];
  82 };
  83
  84 /*! \brief The state change queue. State changes are queued
  85         for processing by a separate thread */
  86 static AST_LIST_HEAD_STATIC(state_changes, state_change);
  87
  88 /*! \brief The device state change notification thread */
  89 static pthread_t change_thread = AST_PTHREADT_NULL;
  90
  91 /*! \brief Flag for the queue */
  92 static ast_cond_t change_pending;
  93
  94 /* Forward declarations */
  95 static int getproviderstate(const char *provider, const char *address);
  96
  97 /*! \brief Find devicestate as text message for output */
  98 const char *devstate2str(int devstate)
  99 {
 100         return devstatestring[devstate];
 101 }
 102
 103 /*! \brief Find out if device is active in a call or not
 104         \note find channels with the device's name in it
 105         This function is only used for channels that does not implement
 106         devicestate natively
 107 */
 108 int ast_parse_device_state(const char *device)
 109 {
 110         struct ast_channel *chan;
 111         char match[AST_CHANNEL_NAME];
 112         int res;
 113
 114         ast_copy_string(match, device, sizeof(match)-1);
 115         strcat(match, "-");
 116         chan = ast_get_channel_by_name_prefix_locked(match, strlen(match));
 117
 118         if (!chan)
 119                 return AST_DEVICE_UNKNOWN;
 120
 121         if (chan->_state == AST_STATE_RINGING)
 122                 res = AST_DEVICE_RINGING;
 123         else
 124                 res = AST_DEVICE_INUSE;
 125
 126         ast_channel_unlock(chan);
 127
 128         return res;
 129 }
 130
 131 /*! \brief Check device state through channel specific function or generic function */
 132 int ast_device_state(const char *device)
 133 {
 134         char *buf;
 135         char *number;
 136         const struct ast_channel_tech *chan_tech;
 137         int res = 0;
 138         /*! \brief Channel driver that provides device state */
 139         char *tech;
 140         /*! \brief Another provider of device state */
 141         char *provider = NULL;
 142
 143         buf = ast_strdupa(device);
 144         tech = strsep(&buf, "/");
 145         number = buf;
 146         if (!number) {
 147                 provider = strsep(&tech, ":");
 148                 if (!provider)
 149                         return AST_DEVICE_INVALID;
 150                 /* We have a provider */
 151                 number = tech;
 152                 tech = NULL;
 153         }
 154
 155         if (provider)  {
 156                 if(option_debug > 2)
 157                         ast_log(LOG_DEBUG, "Checking if I can find provider for \"%s\" - number: %s\n", provider, number);
 158                 return getproviderstate(provider, number);
 159         }
 160         if (option_debug > 3)
 161                 ast_log(LOG_DEBUG, "No provider found, checking channel drivers for %s - %s\n", tech, number);
 162
 163         chan_tech = ast_get_channel_tech(tech);
 164         if (!chan_tech)
 165                 return AST_DEVICE_INVALID;
 166
 167         if (!chan_tech->devicestate)    /* Does the channel driver support device state notification? */
 168                 return ast_parse_device_state(device);  /* No, try the generic function */
 169         else {
 170                 res = chan_tech->devicestate(number);   /* Ask the channel driver for device state */
 171                 if (res == AST_DEVICE_UNKNOWN) {
 172                         res = ast_parse_device_state(device);
 173                         /* at this point we know the device exists, but the channel driver
 174                            could not give us a state; if there is no channel state available,
 175                            it must be 'not in use'
 176                         */
 177                         if (res == AST_DEVICE_UNKNOWN)
 178                                 res = AST_DEVICE_NOT_INUSE;
 179                         return res;
 180                 } else
 181                         return res;
 182         }
 183 }
 184
 185 /*! \brief Add device state provider */
 186 int ast_devstate_prov_add(const char *label, ast_devstate_prov_cb_type callback)
 187 {
 188         struct devstate_prov *devprov;
 189
 190         if (!callback || !(devprov = ast_calloc(1, sizeof(*devprov))))
 191                 return -1;
 192
 193         devprov->callback = callback;
 194         ast_copy_string(devprov->label, label, sizeof(devprov->label));
 195
 196         AST_LIST_LOCK(&devstate_provs);
 197         AST_LIST_INSERT_HEAD(&devstate_provs, devprov, list);
 198         AST_LIST_UNLOCK(&devstate_provs);
 199
 200         return 0;
 201 }
 202
 203 /*! \brief Remove device state provider */
 204 void ast_devstate_prov_del(const char *label)
 205 {
 206         struct devstate_prov *devcb;
 207
 208         AST_LIST_LOCK(&devstate_provs);
 209         AST_LIST_TRAVERSE_SAFE_BEGIN(&devstate_provs, devcb, list) {
 210                 if (!strcasecmp(devcb->label, label)) {
 211                         AST_LIST_REMOVE_CURRENT(&devstate_provs, list);
 212                         free(devcb);
 213                         break;
 214                 }
 215         }
 216         AST_LIST_TRAVERSE_SAFE_END;
 217         AST_LIST_UNLOCK(&devstate_provs);
 218 }
 219
 220 /*! \brief Get provider device state */
 221 static int getproviderstate(const char *provider, const char *address)
 222 {
 223         struct devstate_prov *devprov;
 224         int res = AST_DEVICE_INVALID;
 225
 226
 227         AST_LIST_LOCK(&devstate_provs);
 228         AST_LIST_TRAVERSE_SAFE_BEGIN(&devstate_provs, devprov, list) {
 229                 if(option_debug > 4)
 230                         ast_log(LOG_DEBUG, "Checking provider %s with %s\n", devprov->label, provider);
 231
 232                 if (!strcasecmp(devprov->label, provider)) {
 233                         res = devprov->callback(address);
 234                         break;
 235                 }
 236         }
 237         AST_LIST_TRAVERSE_SAFE_END;
 238         AST_LIST_UNLOCK(&devstate_provs);
 239         return res;
 240 }
 241
 242 /*! \brief Add device state watcher */
 243 int ast_devstate_add(ast_devstate_cb_type callback, void *data)
 244 {
 245         struct devstate_cb *devcb;
 246
 247         if (!callback || !(devcb = ast_calloc(1, sizeof(*devcb))))
 248                 return -1;
 249
 250         devcb->data = data;
 251         devcb->callback = callback;
 252
 253         AST_LIST_LOCK(&devstate_cbs);
 254         AST_LIST_INSERT_HEAD(&devstate_cbs, devcb, list);
 255         AST_LIST_UNLOCK(&devstate_cbs);
 256
 257         return 0;
 258 }
 259
 260 /*! \brief Remove device state watcher */
 261 void ast_devstate_del(ast_devstate_cb_type callback, void *data)
 262 {
 263         struct devstate_cb *devcb;
 264
 265         AST_LIST_LOCK(&devstate_cbs);
 266         AST_LIST_TRAVERSE_SAFE_BEGIN(&devstate_cbs, devcb, list) {
 267                 if ((devcb->callback == callback) && (devcb->data == data)) {
 268                         AST_LIST_REMOVE_CURRENT(&devstate_cbs, list);
 269                         free(devcb);
 270                         break;
 271                 }
 272         }
 273         AST_LIST_TRAVERSE_SAFE_END;
 274         AST_LIST_UNLOCK(&devstate_cbs);
 275 }
 276
 277 /*! \brief Notify callback watchers of change, and notify PBX core for hint updates
 278         Normally executed within a separate thread
 279 */
 280 static void do_state_change(const char *device)
 281 {
 282         int state;
 283         struct devstate_cb *devcb;
 284
 285         state = ast_device_state(device);
 286         if (option_debug > 2)
 287                 ast_log(LOG_DEBUG, "Changing state for %s - state %d (%s)\n", device, state, devstate2str(state));
 288
 289         AST_LIST_LOCK(&devstate_cbs);
 290         AST_LIST_TRAVERSE(&devstate_cbs, devcb, list)
 291                 devcb->callback(device, state, devcb->data);
 292         AST_LIST_UNLOCK(&devstate_cbs);
 293
 294         ast_hint_state_changed(device);
 295 }
 296
 297 static int __ast_device_state_changed_literal(char *buf, int norecurse)
 298 {
 299         char *device;
 300         struct state_change *change;
 301         char *tmp = NULL;
 302
 303         if (option_debug > 2)
 304                 ast_log(LOG_DEBUG, "Notification of state change to be queued on device/channel %s\n", buf);
 305
 306         device = buf;
 307
 308         if (change_thread == AST_PTHREADT_NULL || !(change = ast_calloc(1, sizeof(*change) + strlen(device)))) {
 309                 /* we could not allocate a change struct, or */
 310                 /* there is no background thread, so process the change now */
 311                 do_state_change(device);
 312         } else {
 313                 /* queue the change */
 314                 strcpy(change->device, device);
 315                 AST_LIST_LOCK(&state_changes);
 316                 AST_LIST_INSERT_TAIL(&state_changes, change, list);
 317                 if (AST_LIST_FIRST(&state_changes) == change)
 318                         /* the list was empty, signal the thread */
 319                         ast_cond_signal(&change_pending);
 320                 AST_LIST_UNLOCK(&state_changes);
 321         }
 322
 323         /* The problem with this API is that a device may be called with the unique
 324          * identifier appended or not, but it's separated from the channel name
 325          * with a '-', which is also a legitimate character in a channel name.  So,
 326          * we have to force both names to get their names checked for state changes
 327          * to ensure that the right one gets notified.  Not a huge performance hit,
 328          * but it might could be fixed by an enterprising programmer in trunk.
 329          */
 330         if (!norecurse && (tmp = strrchr(device, '-'))) {
 331                 *tmp = '\0';
 332                 __ast_device_state_changed_literal(device, 1);
 333         }
 334
 335         return 1;
 336 }
 337
 338 int ast_device_state_changed_literal(const char *dev)
 339 {
 340         char *buf;
 341         buf = ast_strdupa(dev);
 342         return __ast_device_state_changed_literal(buf, 0);
 343 }
 344
 345 /*! \brief Accept change notification, add it to change queue */
 346 int ast_device_state_changed(const char *fmt, ...)
 347 {
 348         char buf[AST_MAX_EXTENSION];
 349         va_list ap;
 350
 351         va_start(ap, fmt);
 352         vsnprintf(buf, sizeof(buf), fmt, ap);
 353         va_end(ap);
 354         return __ast_device_state_changed_literal(buf, 0);
 355 }
 356
 357 /*! \brief Go through the dev state change queue and update changes in the dev state thread */
 358 static void *do_devstate_changes(void *data)
 359 {
 360         struct state_change *cur;
 361
 362         AST_LIST_LOCK(&state_changes);
 363         for(;;) {
 364                 /* the list lock will _always_ be held at this point in the loop */
 365                 cur = AST_LIST_REMOVE_HEAD(&state_changes, list);
 366                 if (cur) {
 367                         /* we got an entry, so unlock the list while we process it */
 368                         AST_LIST_UNLOCK(&state_changes);
 369                         do_state_change(cur->device);
 370                         free(cur);
 371                         AST_LIST_LOCK(&state_changes);
 372                 } else {
 373                         /* there was no entry, so atomically unlock the list and wait for
 374                            the condition to be signalled (returns with the lock held) */
 375                         ast_cond_wait(&change_pending, &state_changes.lock);
 376                 }
 377         }
 378
 379         return NULL;
 380 }
 381
 382 /*! \brief Initialize the device state engine in separate thread */
 383 int ast_device_state_engine_init(void)
 384 {
 385         ast_cond_init(&change_pending, NULL);
 386         if (ast_pthread_create_background(&change_thread, NULL, do_devstate_changes, NULL) < 0) {
 387                 ast_log(LOG_ERROR, "Unable to start device state change thread.\n");
 388                 return -1;
 389         }
 390
 391         return 0;
 392 }