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Asterisk developer's documentation


devicestate.c

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00001 /*
00002  * Asterisk -- An open source telephony toolkit.
00003  *
00004  * Copyright (C) 1999 - 2008, Digium, Inc.
00005  *
00006  * Mark Spencer <markster@digium.com>
00007  * Russell Bryant <russell@digium.com>
00008  *
00009  * See http://www.asterisk.org for more information about
00010  * the Asterisk project. Please do not directly contact
00011  * any of the maintainers of this project for assistance;
00012  * the project provides a web site, mailing lists and IRC
00013  * channels for your use.
00014  *
00015  * This program is free software, distributed under the terms of
00016  * the GNU General Public License Version 2. See the LICENSE file
00017  * at the top of the source tree.
00018  */
00019 
00020 /*! \file
00021  *
00022  * \brief Device state management
00023  *
00024  * \author Mark Spencer <markster@digium.com> 
00025  * \author Russell Bryant <russell@digium.com>
00026  *
00027  * \arg \ref AstExtState
00028  */
00029 
00030 /*! \page AstExtState Extension and device states in Asterisk
00031  *
00032  * (Note that these descriptions of device states and extension
00033  * states have not been updated to the way things work
00034  * in Asterisk 1.6.)
00035  *
00036  * Asterisk has an internal system that reports states
00037  * for an extension. By using the dialplan priority -1,
00038  * also called a \b hint, a connection can be made from an
00039  * extension to one or many devices. The state of the extension
00040  * now depends on the combined state of the devices.
00041  *
00042  * The device state is basically based on the current calls.
00043  * If the devicestate engine can find a call from or to the
00044  * device, it's in use.
00045  * 
00046  * Some channel drivers implement a callback function for 
00047  * a better level of reporting device states. The SIP channel
00048  * has a complicated system for this, which is improved 
00049  * by adding call limits to the configuration.
00050  * 
00051  * Functions that want to check the status of an extension
00052  * register themself as a \b watcher.
00053  * Watchers in this system can subscribe either to all extensions
00054  * or just a specific extensions.
00055  *
00056  * For non-device related states, there's an API called
00057  * devicestate providers. This is an extendible system for
00058  * delivering state information from outside sources or
00059  * functions within Asterisk. Currently we have providers
00060  * for app_meetme.c - the conference bridge - and call
00061  * parking (metermaids).
00062  *
00063  * There are manly three subscribers to extension states 
00064  * within Asterisk:
00065  * - AMI, the manager interface
00066  * - app_queue.c - the Queue dialplan application
00067  * - SIP subscriptions, a.k.a. "blinking lamps" or 
00068  *   "buddy lists"
00069  *
00070  * The CLI command "show hints" show last known state
00071  *
00072  * \note None of these handle user states, like an IM presence
00073  * system. res_jabber.c can subscribe and watch such states
00074  * in jabber/xmpp based systems.
00075  *
00076  * \section AstDevStateArch Architecture for devicestates
00077  *
00078  * When a channel driver or asterisk app changes state for 
00079  * a watched object, it alerts the core. The core queues
00080  * a change. When the change is processed, there's a query
00081  * sent to the channel driver/provider if there's a function
00082  * to handle that, otherwise a channel walk is issued to find
00083  * a channel that involves the object.
00084  * 
00085  * The changes are queued and processed by a separate thread.
00086  * This thread calls the watchers subscribing to status 
00087  * changes for the object. For manager, this results 
00088  * in events. For SIP, NOTIFY requests.
00089  *
00090  * - Device states
00091  *    \arg \ref devicestate.c 
00092  *    \arg \ref devicestate.h 
00093  *
00094  * \section AstExtStateArch Architecture for extension states
00095  * 
00096  * Hints are connected to extension. If an extension changes state
00097  * it checks the hint devices. If there is a hint, the callbacks into
00098  * device states are checked. The aggregated state is set for the hint
00099  * and reported back.
00100  *
00101  * - Extension states
00102  *    \arg \ref AstENUM ast_extension_states
00103  *    \arg \ref pbx.c 
00104  *    \arg \ref pbx.h 
00105  * - Structures
00106  *    - \ref ast_state_cb struct.  Callbacks for watchers
00107  *    - Callback ast_state_cb_type
00108  *    - \ref ast_hint struct.
00109  *    - Functions
00110  *    - ast_extension_state_add()
00111  *    - ast_extension_state_del()
00112  *    - ast_get_hint()
00113  * 
00114  */
00115 
00116 #include "asterisk.h"
00117 
00118 ASTERISK_FILE_VERSION(__FILE__, "$Revision: 294500 $")
00119 
00120 #include "asterisk/_private.h"
00121 #include "asterisk/channel.h"
00122 #include "asterisk/utils.h"
00123 #include "asterisk/lock.h"
00124 #include "asterisk/linkedlists.h"
00125 #include "asterisk/devicestate.h"
00126 #include "asterisk/pbx.h"
00127 #include "asterisk/app.h"
00128 #include "asterisk/event.h"
00129 
00130 /*! \brief Device state strings for printing */
00131 static const char *devstatestring[][2] = {
00132    { /* 0 AST_DEVICE_UNKNOWN */     "Unknown",     "UNKNOWN"     }, /*!< Valid, but unknown state */
00133    { /* 1 AST_DEVICE_NOT_INUSE */   "Not in use",  "NOT_INUSE"   }, /*!< Not used */
00134    { /* 2 AST_DEVICE IN USE */      "In use",      "INUSE"       }, /*!< In use */
00135    { /* 3 AST_DEVICE_BUSY */        "Busy",        "BUSY"        }, /*!< Busy */
00136    { /* 4 AST_DEVICE_INVALID */     "Invalid",     "INVALID"     }, /*!< Invalid - not known to Asterisk */
00137    { /* 5 AST_DEVICE_UNAVAILABLE */ "Unavailable", "UNAVAILABLE" }, /*!< Unavailable (not registered) */
00138    { /* 6 AST_DEVICE_RINGING */     "Ringing",     "RINGING"     }, /*!< Ring, ring, ring */
00139    { /* 7 AST_DEVICE_RINGINUSE */   "Ring+Inuse",  "RINGINUSE"   }, /*!< Ring and in use */
00140    { /* 8 AST_DEVICE_ONHOLD */      "On Hold",      "ONHOLD"      }, /*!< On Hold */
00141 };
00142 
00143 /*!\brief Mapping for channel states to device states */
00144 static const struct chan2dev {
00145    enum ast_channel_state chan;
00146    enum ast_device_state dev;
00147 } chan2dev[] = {
00148    { AST_STATE_DOWN,            AST_DEVICE_NOT_INUSE },
00149    { AST_STATE_RESERVED,        AST_DEVICE_INUSE },
00150    { AST_STATE_OFFHOOK,         AST_DEVICE_INUSE },
00151    { AST_STATE_DIALING,         AST_DEVICE_INUSE },
00152    { AST_STATE_RING,            AST_DEVICE_INUSE },
00153    { AST_STATE_RINGING,         AST_DEVICE_RINGING },
00154    { AST_STATE_UP,              AST_DEVICE_INUSE },
00155    { AST_STATE_BUSY,            AST_DEVICE_BUSY },
00156    { AST_STATE_DIALING_OFFHOOK, AST_DEVICE_INUSE },
00157    { AST_STATE_PRERING,         AST_DEVICE_RINGING },
00158    { -100,                      -100 },
00159 };
00160 
00161 /*! \brief  A device state provider (not a channel) */
00162 struct devstate_prov {
00163    char label[40];
00164    ast_devstate_prov_cb_type callback;
00165    AST_RWLIST_ENTRY(devstate_prov) list;
00166 };
00167 
00168 /*! \brief A list of providers */
00169 static AST_RWLIST_HEAD_STATIC(devstate_provs, devstate_prov);
00170 
00171 struct state_change {
00172    AST_LIST_ENTRY(state_change) list;
00173    char device[1];
00174 };
00175 
00176 /*! \brief The state change queue. State changes are queued
00177    for processing by a separate thread */
00178 static AST_LIST_HEAD_STATIC(state_changes, state_change);
00179 
00180 /*! \brief The device state change notification thread */
00181 static pthread_t change_thread = AST_PTHREADT_NULL;
00182 
00183 /*! \brief Flag for the queue */
00184 static ast_cond_t change_pending;
00185 
00186 struct devstate_change {
00187    AST_LIST_ENTRY(devstate_change) entry;
00188    uint32_t state;
00189    struct ast_eid eid;
00190    char device[1];
00191 };
00192 
00193 struct {
00194    pthread_t thread;
00195    struct ast_event_sub *event_sub;
00196    ast_cond_t cond;
00197    ast_mutex_t lock;
00198    AST_LIST_HEAD_NOLOCK(, devstate_change) devstate_change_q;
00199    unsigned int enabled:1;
00200 } devstate_collector = {
00201    .thread = AST_PTHREADT_NULL,
00202    .enabled = 0,
00203 };
00204 
00205 /* Forward declarations */
00206 static int getproviderstate(const char *provider, const char *address);
00207 
00208 /*! \brief Find devicestate as text message for output */
00209 const char *ast_devstate2str(enum ast_device_state devstate) 
00210 {
00211    return devstatestring[devstate][0];
00212 }
00213 
00214 /* Deprecated interface (not prefixed with ast_) */
00215 const char *devstate2str(enum ast_device_state devstate) 
00216 {
00217    return devstatestring[devstate][0];
00218 }
00219 
00220 enum ast_device_state ast_state_chan2dev(enum ast_channel_state chanstate)
00221 {
00222    int i;
00223    chanstate &= 0xFFFF;
00224    for (i = 0; chan2dev[i].chan != -100; i++) {
00225       if (chan2dev[i].chan == chanstate) {
00226          return chan2dev[i].dev;
00227       }
00228    }
00229    return AST_DEVICE_UNKNOWN;
00230 }
00231 
00232 /* Parseable */
00233 const char *ast_devstate_str(enum ast_device_state state)
00234 {
00235    return devstatestring[state][1];
00236 }
00237 
00238 enum ast_device_state ast_devstate_val(const char *val)
00239 {
00240    if (!strcasecmp(val, "NOT_INUSE"))
00241       return AST_DEVICE_NOT_INUSE;
00242    else if (!strcasecmp(val, "INUSE"))
00243       return AST_DEVICE_INUSE;
00244    else if (!strcasecmp(val, "BUSY"))
00245       return AST_DEVICE_BUSY;
00246    else if (!strcasecmp(val, "INVALID"))
00247       return AST_DEVICE_INVALID;
00248    else if (!strcasecmp(val, "UNAVAILABLE"))
00249       return AST_DEVICE_UNAVAILABLE;
00250    else if (!strcasecmp(val, "RINGING"))
00251       return AST_DEVICE_RINGING;
00252    else if (!strcasecmp(val, "RINGINUSE"))
00253       return AST_DEVICE_RINGINUSE;
00254    else if (!strcasecmp(val, "ONHOLD"))
00255       return AST_DEVICE_ONHOLD;
00256 
00257    return AST_DEVICE_UNKNOWN;
00258 }
00259 
00260 /*! \brief Find out if device is active in a call or not 
00261    \note find channels with the device's name in it
00262    This function is only used for channels that does not implement 
00263    devicestate natively
00264 */
00265 enum ast_device_state ast_parse_device_state(const char *device)
00266 {
00267    struct ast_channel *chan;
00268    char match[AST_CHANNEL_NAME];
00269    enum ast_device_state res;
00270 
00271    ast_copy_string(match, device, sizeof(match)-1);
00272    strcat(match, "-");
00273    chan = ast_get_channel_by_name_prefix_locked(match, strlen(match));
00274 
00275    if (!chan)
00276       return AST_DEVICE_UNKNOWN;
00277 
00278    if (chan->_state == AST_STATE_RINGING)
00279       res = AST_DEVICE_RINGING;
00280    else
00281       res = AST_DEVICE_INUSE;
00282    
00283    ast_channel_unlock(chan);
00284 
00285    return res;
00286 }
00287 
00288 static enum ast_device_state devstate_cached(const char *device)
00289 {
00290    enum ast_device_state res = AST_DEVICE_UNKNOWN;
00291    struct ast_event *event;
00292 
00293    event = ast_event_get_cached(AST_EVENT_DEVICE_STATE,
00294       AST_EVENT_IE_DEVICE, AST_EVENT_IE_PLTYPE_STR, device,
00295       AST_EVENT_IE_END);
00296 
00297    if (!event)
00298       return res;
00299 
00300    res = ast_event_get_ie_uint(event, AST_EVENT_IE_STATE);
00301 
00302    ast_event_destroy(event);
00303 
00304    return res;
00305 }
00306 
00307 /*! \brief Check device state through channel specific function or generic function */
00308 static enum ast_device_state _ast_device_state(const char *device, int check_cache)
00309 {
00310    char *buf;
00311    char *number;
00312    const struct ast_channel_tech *chan_tech;
00313    enum ast_device_state res;
00314    /*! \brief Channel driver that provides device state */
00315    char *tech;
00316    /*! \brief Another provider of device state */
00317    char *provider = NULL;
00318 
00319    /* If the last known state is cached, just return that */
00320    if (check_cache) {
00321       res = devstate_cached(device);
00322       if (res != AST_DEVICE_UNKNOWN) {
00323          return res;
00324       }
00325    }
00326 
00327    buf = ast_strdupa(device);
00328    tech = strsep(&buf, "/");
00329    if (!(number = buf)) {
00330       provider = strsep(&tech, ":");
00331       if (!tech) {
00332          return AST_DEVICE_INVALID;
00333       }
00334       /* We have a provider */
00335       number = tech;
00336       tech = NULL;
00337    }
00338 
00339    if (provider)  {
00340       ast_debug(3, "Checking if I can find provider for \"%s\" - number: %s\n", provider, number);
00341       return getproviderstate(provider, number);
00342    }
00343 
00344    ast_debug(4, "No provider found, checking channel drivers for %s - %s\n", tech, number);
00345 
00346    if (!(chan_tech = ast_get_channel_tech(tech)))
00347       return AST_DEVICE_INVALID;
00348 
00349    if (!(chan_tech->devicestate)) /* Does the channel driver support device state notification? */
00350       return ast_parse_device_state(device); /* No, try the generic function */
00351 
00352    res = chan_tech->devicestate(number);
00353 
00354    if (res != AST_DEVICE_UNKNOWN)
00355       return res;
00356 
00357    res = ast_parse_device_state(device);
00358 
00359    return res;
00360 }
00361 
00362 enum ast_device_state ast_device_state(const char *device)
00363 {
00364    /* This function is called from elsewhere in the code to find out the
00365     * current state of a device.  Check the cache, first. */
00366 
00367    return _ast_device_state(device, 1);
00368 }
00369 
00370 /*! \brief Add device state provider */
00371 int ast_devstate_prov_add(const char *label, ast_devstate_prov_cb_type callback)
00372 {
00373    struct devstate_prov *devprov;
00374 
00375    if (!callback || !(devprov = ast_calloc(1, sizeof(*devprov))))
00376       return -1;
00377 
00378    devprov->callback = callback;
00379    ast_copy_string(devprov->label, label, sizeof(devprov->label));
00380 
00381    AST_RWLIST_WRLOCK(&devstate_provs);
00382    AST_RWLIST_INSERT_HEAD(&devstate_provs, devprov, list);
00383    AST_RWLIST_UNLOCK(&devstate_provs);
00384 
00385    return 0;
00386 }
00387 
00388 /*! \brief Remove device state provider */
00389 int ast_devstate_prov_del(const char *label)
00390 {
00391    struct devstate_prov *devcb;
00392    int res = -1;
00393 
00394    AST_RWLIST_WRLOCK(&devstate_provs);
00395    AST_RWLIST_TRAVERSE_SAFE_BEGIN(&devstate_provs, devcb, list) {
00396       if (!strcasecmp(devcb->label, label)) {
00397          AST_RWLIST_REMOVE_CURRENT(list);
00398          ast_free(devcb);
00399          res = 0;
00400          break;
00401       }
00402    }
00403    AST_RWLIST_TRAVERSE_SAFE_END;
00404    AST_RWLIST_UNLOCK(&devstate_provs);
00405 
00406    return res;
00407 }
00408 
00409 /*! \brief Get provider device state */
00410 static int getproviderstate(const char *provider, const char *address)
00411 {
00412    struct devstate_prov *devprov;
00413    int res = AST_DEVICE_INVALID;
00414 
00415    AST_RWLIST_RDLOCK(&devstate_provs);
00416    AST_RWLIST_TRAVERSE(&devstate_provs, devprov, list) {
00417       ast_debug(5, "Checking provider %s with %s\n", devprov->label, provider);
00418 
00419       if (!strcasecmp(devprov->label, provider)) {
00420          res = devprov->callback(address);
00421          break;
00422       }
00423    }
00424    AST_RWLIST_UNLOCK(&devstate_provs);
00425 
00426    return res;
00427 }
00428 
00429 static void devstate_event(const char *device, enum ast_device_state state)
00430 {
00431    struct ast_event *event;
00432    enum ast_event_type event_type;
00433 
00434    if (devstate_collector.enabled) {
00435       /* Distributed device state is enabled, so this state change is a change
00436        * for a single server, not the real state. */
00437       event_type = AST_EVENT_DEVICE_STATE_CHANGE;
00438    } else {
00439       event_type = AST_EVENT_DEVICE_STATE;
00440    }
00441 
00442    ast_debug(3, "device '%s' state '%d'\n", device, state);
00443 
00444    if (!(event = ast_event_new(event_type,
00445          AST_EVENT_IE_DEVICE, AST_EVENT_IE_PLTYPE_STR, device,
00446          AST_EVENT_IE_STATE, AST_EVENT_IE_PLTYPE_UINT, state,
00447          AST_EVENT_IE_END))) {
00448       return;
00449    }
00450 
00451    ast_event_queue_and_cache(event);
00452 }
00453 
00454 /*! Called by the state change thread to find out what the state is, and then
00455  *  to queue up the state change event */
00456 static void do_state_change(const char *device)
00457 {
00458    enum ast_device_state state;
00459 
00460    state = _ast_device_state(device, 0);
00461 
00462    ast_debug(3, "Changing state for %s - state %d (%s)\n", device, state, ast_devstate2str(state));
00463 
00464    devstate_event(device, state);
00465 }
00466 
00467 int ast_devstate_changed_literal(enum ast_device_state state, const char *device)
00468 {
00469    struct state_change *change;
00470 
00471    /* 
00472     * If we know the state change (how nice of the caller of this function!)
00473     * then we can just generate a device state event. 
00474     *
00475     * Otherwise, we do the following:
00476     *   - Queue an event up to another thread that the state has changed
00477     *   - In the processing thread, it calls the callback provided by the
00478     *     device state provider (which may or may not be a channel driver)
00479     *     to determine the state.
00480     *   - If the device state provider does not know the state, or this is
00481     *     for a channel and the channel driver does not implement a device
00482     *     state callback, then we will look through the channel list to
00483     *     see if we can determine a state based on active calls.
00484     *   - Once a state has been determined, a device state event is generated.
00485     */
00486 
00487    if (state != AST_DEVICE_UNKNOWN) {
00488       devstate_event(device, state);
00489    } else if (change_thread == AST_PTHREADT_NULL || !(change = ast_calloc(1, sizeof(*change) + strlen(device)))) {
00490       /* we could not allocate a change struct, or */
00491       /* there is no background thread, so process the change now */
00492       do_state_change(device);
00493    } else {
00494       /* queue the change */
00495       strcpy(change->device, device);
00496       AST_LIST_LOCK(&state_changes);
00497       AST_LIST_INSERT_TAIL(&state_changes, change, list);
00498       ast_cond_signal(&change_pending);
00499       AST_LIST_UNLOCK(&state_changes);
00500    }
00501 
00502    return 1;
00503 }
00504 
00505 int ast_device_state_changed_literal(const char *dev)
00506 {
00507    return ast_devstate_changed_literal(AST_DEVICE_UNKNOWN, dev);
00508 }
00509 
00510 int ast_devstate_changed(enum ast_device_state state, const char *fmt, ...) 
00511 {
00512    char buf[AST_MAX_EXTENSION];
00513    va_list ap;
00514 
00515    va_start(ap, fmt);
00516    vsnprintf(buf, sizeof(buf), fmt, ap);
00517    va_end(ap);
00518 
00519    return ast_devstate_changed_literal(state, buf);
00520 }
00521 
00522 int ast_device_state_changed(const char *fmt, ...) 
00523 {
00524    char buf[AST_MAX_EXTENSION];
00525    va_list ap;
00526 
00527    va_start(ap, fmt);
00528    vsnprintf(buf, sizeof(buf), fmt, ap);
00529    va_end(ap);
00530 
00531    return ast_devstate_changed_literal(AST_DEVICE_UNKNOWN, buf);
00532 }
00533 
00534 /*! \brief Go through the dev state change queue and update changes in the dev state thread */
00535 static void *do_devstate_changes(void *data)
00536 {
00537    struct state_change *next, *current;
00538 
00539    for (;;) {
00540       /* This basically pops off any state change entries, resets the list back to NULL, unlocks, and processes each state change */
00541       AST_LIST_LOCK(&state_changes);
00542       if (AST_LIST_EMPTY(&state_changes))
00543          ast_cond_wait(&change_pending, &state_changes.lock);
00544       next = AST_LIST_FIRST(&state_changes);
00545       AST_LIST_HEAD_INIT_NOLOCK(&state_changes);
00546       AST_LIST_UNLOCK(&state_changes);
00547 
00548       /* Process each state change */
00549       while ((current = next)) {
00550          next = AST_LIST_NEXT(current, list);
00551          do_state_change(current->device);
00552          ast_free(current);
00553       }
00554    }
00555 
00556    return NULL;
00557 }
00558 
00559 static void destroy_devstate_change(struct devstate_change *sc)
00560 {
00561    ast_free(sc);
00562 }
00563 
00564 #define MAX_SERVERS 64
00565 struct change_collection {
00566    struct devstate_change states[MAX_SERVERS];
00567    size_t num_states;
00568 };
00569 
00570 static void devstate_cache_cb(const struct ast_event *event, void *data)
00571 {
00572    struct change_collection *collection = data;
00573    int i;
00574    const struct ast_eid *eid;
00575 
00576    if (collection->num_states == ARRAY_LEN(collection->states)) {
00577       ast_log(LOG_ERROR, "More per-server state values than we have room for (MAX_SERVERS is %d)\n",
00578          MAX_SERVERS);
00579       return;
00580    }
00581 
00582    if (!(eid = ast_event_get_ie_raw(event, AST_EVENT_IE_EID))) {
00583       ast_log(LOG_ERROR, "Device state change event with no EID\n");
00584       return;
00585    }
00586 
00587    i = collection->num_states;
00588 
00589    collection->states[i].state = ast_event_get_ie_uint(event, AST_EVENT_IE_STATE);
00590    collection->states[i].eid = *eid;
00591 
00592    collection->num_states++;
00593 }
00594 
00595 static void process_collection(const char *device, struct change_collection *collection)
00596 {
00597    int i;
00598    struct ast_devstate_aggregate agg;
00599    enum ast_device_state state;
00600    struct ast_event *event;
00601 
00602    ast_devstate_aggregate_init(&agg);
00603 
00604    for (i = 0; i < collection->num_states; i++) {
00605       ast_debug(1, "Adding per-server state of '%s' for '%s'\n", 
00606          ast_devstate2str(collection->states[i].state), device);
00607       ast_devstate_aggregate_add(&agg, collection->states[i].state);
00608    }
00609 
00610    state = ast_devstate_aggregate_result(&agg);
00611 
00612    ast_debug(1, "Aggregate devstate result is '%s' for '%s'\n",
00613       ast_devstate2str(state), device);
00614 
00615    event = ast_event_get_cached(AST_EVENT_DEVICE_STATE,
00616       AST_EVENT_IE_DEVICE, AST_EVENT_IE_PLTYPE_STR, device,
00617       AST_EVENT_IE_END);
00618    
00619    if (event) {
00620       enum ast_device_state old_state;
00621 
00622       old_state = ast_event_get_ie_uint(event, AST_EVENT_IE_STATE);
00623       
00624       ast_event_destroy(event);
00625 
00626       if (state == old_state) {
00627          /* No change since last reported device state */
00628          ast_debug(1, "Aggregate state for device '%s' has not changed from '%s'\n",
00629             device, ast_devstate2str(state));
00630          return;
00631       }
00632    }
00633 
00634    ast_debug(1, "Aggregate state for device '%s' has changed to '%s'\n",
00635       device, ast_devstate2str(state));
00636 
00637    event = ast_event_new(AST_EVENT_DEVICE_STATE,
00638       AST_EVENT_IE_DEVICE, AST_EVENT_IE_PLTYPE_STR, device,
00639       AST_EVENT_IE_STATE, AST_EVENT_IE_PLTYPE_UINT, state,
00640       AST_EVENT_IE_END);
00641 
00642    if (!event) {
00643       return;
00644    }
00645 
00646    ast_event_queue_and_cache(event);
00647 }
00648 
00649 static void handle_devstate_change(struct devstate_change *sc)
00650 {
00651    struct ast_event_sub *tmp_sub;
00652    struct change_collection collection = {
00653       .num_states = 0,
00654    };
00655 
00656    ast_debug(1, "Processing device state change for '%s'\n", sc->device);
00657 
00658    if (!(tmp_sub = ast_event_subscribe_new(AST_EVENT_DEVICE_STATE_CHANGE, devstate_cache_cb, &collection))) {
00659       ast_log(LOG_ERROR, "Failed to create subscription\n");
00660       return;
00661    }
00662 
00663    if (ast_event_sub_append_ie_str(tmp_sub, AST_EVENT_IE_DEVICE, sc->device)) {
00664       ast_log(LOG_ERROR, "Failed to append device IE\n");
00665       ast_event_sub_destroy(tmp_sub);
00666       return;
00667    }
00668 
00669    /* Populate the collection of device states from the cache */
00670    ast_event_dump_cache(tmp_sub);
00671 
00672    process_collection(sc->device, &collection);
00673 
00674    ast_event_sub_destroy(tmp_sub);
00675 }
00676 
00677 static void *run_devstate_collector(void *data)
00678 {
00679    for (;;) {
00680       struct devstate_change *sc;
00681 
00682       ast_mutex_lock(&devstate_collector.lock);
00683       while (!(sc = AST_LIST_REMOVE_HEAD(&devstate_collector.devstate_change_q, entry)))
00684          ast_cond_wait(&devstate_collector.cond, &devstate_collector.lock);
00685       ast_mutex_unlock(&devstate_collector.lock);
00686 
00687       handle_devstate_change(sc);
00688 
00689       destroy_devstate_change(sc);
00690    }
00691 
00692    return NULL;
00693 }
00694 
00695 static void devstate_change_collector_cb(const struct ast_event *event, void *data)
00696 {
00697    struct devstate_change *sc;
00698    const char *device;
00699    const struct ast_eid *eid;
00700    uint32_t state;
00701 
00702    device = ast_event_get_ie_str(event, AST_EVENT_IE_DEVICE);
00703    eid = ast_event_get_ie_raw(event, AST_EVENT_IE_EID);
00704    state = ast_event_get_ie_uint(event, AST_EVENT_IE_STATE);
00705 
00706    if (ast_strlen_zero(device) || !eid) {
00707       ast_log(LOG_ERROR, "Invalid device state change event received\n");
00708       return;
00709    }
00710 
00711    if (!(sc = ast_calloc(1, sizeof(*sc) + strlen(device))))
00712       return;
00713 
00714    strcpy(sc->device, device);
00715    sc->eid = *eid;
00716    sc->state = state;
00717 
00718    ast_mutex_lock(&devstate_collector.lock);
00719    AST_LIST_INSERT_TAIL(&devstate_collector.devstate_change_q, sc, entry);
00720    ast_cond_signal(&devstate_collector.cond);
00721    ast_mutex_unlock(&devstate_collector.lock);
00722 }
00723 
00724 /*! \brief Initialize the device state engine in separate thread */
00725 int ast_device_state_engine_init(void)
00726 {
00727    ast_cond_init(&change_pending, NULL);
00728    if (ast_pthread_create_background(&change_thread, NULL, do_devstate_changes, NULL) < 0) {
00729       ast_log(LOG_ERROR, "Unable to start device state change thread.\n");
00730       return -1;
00731    }
00732 
00733    return 0;
00734 }
00735 
00736 void ast_devstate_aggregate_init(struct ast_devstate_aggregate *agg)
00737 {
00738    memset(agg, 0, sizeof(*agg));
00739 
00740    agg->all_unknown = 1;
00741    agg->all_unavail = 1;
00742    agg->all_busy = 1;
00743    agg->all_free = 1;
00744 }
00745 
00746 void ast_devstate_aggregate_add(struct ast_devstate_aggregate *agg, enum ast_device_state state)
00747 {
00748    switch (state) {
00749    case AST_DEVICE_NOT_INUSE:
00750       agg->all_unknown = 0;
00751       agg->all_unavail = 0;
00752       agg->all_busy = 0;
00753       break;
00754    case AST_DEVICE_INUSE:
00755       agg->in_use = 1;
00756       agg->all_unavail = 0;
00757       agg->all_free = 0;
00758       agg->all_unknown = 0;
00759       break;
00760    case AST_DEVICE_RINGING:
00761       agg->ring = 1;
00762       agg->all_unavail = 0;
00763       agg->all_free = 0;
00764       agg->all_unknown = 0;
00765       break;
00766    case AST_DEVICE_RINGINUSE:
00767       agg->in_use = 1;
00768       agg->ring = 1;
00769       agg->all_unavail = 0;
00770       agg->all_free = 0;
00771       agg->all_unknown = 0;
00772       break;
00773    case AST_DEVICE_ONHOLD:
00774       agg->all_unknown = 0;
00775       agg->all_unavail = 0;
00776       agg->all_free = 0;
00777       agg->on_hold = 1;
00778       break;
00779    case AST_DEVICE_BUSY:
00780       agg->all_unknown = 0;
00781       agg->all_unavail = 0;
00782       agg->all_free = 0;
00783       agg->busy = 1;
00784       agg->in_use = 1;
00785       break;
00786    case AST_DEVICE_UNAVAILABLE:
00787       agg->all_unknown = 0;
00788    case AST_DEVICE_INVALID:
00789       agg->all_busy = 0;
00790       agg->all_free = 0;
00791       break;
00792    case AST_DEVICE_UNKNOWN:
00793       agg->all_busy = 0;
00794       agg->all_free = 0;
00795       break;
00796    case AST_DEVICE_TOTAL: /* not a device state, included for completeness. */
00797       break;
00798    }
00799 }
00800 
00801 
00802 enum ast_device_state ast_devstate_aggregate_result(struct ast_devstate_aggregate *agg)
00803 {
00804    if (agg->all_free)
00805       return AST_DEVICE_NOT_INUSE;
00806    if ((agg->in_use || agg->on_hold) && agg->ring)
00807       return AST_DEVICE_RINGINUSE;
00808    if (agg->ring)
00809       return AST_DEVICE_RINGING;
00810    if (agg->busy)
00811       return AST_DEVICE_BUSY;
00812    if (agg->in_use)
00813       return AST_DEVICE_INUSE;
00814    if (agg->on_hold)
00815       return AST_DEVICE_ONHOLD;
00816    if (agg->all_busy)
00817       return AST_DEVICE_BUSY;
00818    if (agg->all_unknown)
00819       return AST_DEVICE_UNKNOWN;
00820    if (agg->all_unavail)
00821       return AST_DEVICE_UNAVAILABLE;
00822 
00823    return AST_DEVICE_NOT_INUSE;
00824 }
00825 
00826 int ast_enable_distributed_devstate(void)
00827 {
00828    if (devstate_collector.enabled) {
00829       return 0;
00830    }
00831 
00832    devstate_collector.event_sub = ast_event_subscribe(AST_EVENT_DEVICE_STATE_CHANGE,
00833       devstate_change_collector_cb, NULL, AST_EVENT_IE_END);
00834 
00835    if (!devstate_collector.event_sub) {
00836       ast_log(LOG_ERROR, "Failed to create subscription for the device state change collector\n");
00837       return -1;
00838    }
00839 
00840    ast_mutex_init(&devstate_collector.lock);
00841    ast_cond_init(&devstate_collector.cond, NULL);
00842    if (ast_pthread_create_background(&devstate_collector.thread, NULL, run_devstate_collector, NULL) < 0) {
00843       ast_log(LOG_ERROR, "Unable to start device state collector thread.\n");
00844       return -1;
00845    }
00846 
00847    devstate_collector.enabled = 1;
00848 
00849    return 0;
00850 }