fixes ast_transfer stall until hangup if called with a channel that doesn't support...

[asterisk/asterisk.git] / main / channel.c

/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 1999 - 2006, Digium, Inc.
 *
 * Mark Spencer <markster@digium.com>
 *
 * See http://www.asterisk.org for more information about
 * the Asterisk project. Please do not directly contact
 * any of the maintainers of this project for assistance;
 * the project provides a web site, mailing lists and IRC
 * channels for your use.
 *
 * This program is free software, distributed under the terms of
 * the GNU General Public License Version 2. See the LICENSE file
 * at the top of the source tree.
 */

/*! \file
 *
 * \brief Channel Management
 *
 * \author Mark Spencer <markster@digium.com>
 */

#include "asterisk.h"

ASTERISK_FILE_VERSION(__FILE__, "$Revision$")

#include "asterisk/_private.h"

#include <sys/time.h>
#include <signal.h>
#include <math.h>

#include "asterisk/paths.h"     /* use ast_config_AST_SYSTEM_NAME */

#include "asterisk/pbx.h"
#include "asterisk/frame.h"
#include "asterisk/sched.h"
#include "asterisk/channel.h"
#include "asterisk/musiconhold.h"
#include "asterisk/say.h"
#include "asterisk/file.h"
#include "asterisk/cli.h"
#include "asterisk/translate.h"
#include "asterisk/manager.h"
#include "asterisk/cel.h"
#include "asterisk/chanvars.h"
#include "asterisk/linkedlists.h"
#include "asterisk/indications.h"
#include "asterisk/monitor.h"
#include "asterisk/causes.h"
#include "asterisk/callerid.h"
#include "asterisk/utils.h"
#include "asterisk/lock.h"
#include "asterisk/app.h"
#include "asterisk/transcap.h"
#include "asterisk/devicestate.h"
#include "asterisk/sha1.h"
#include "asterisk/threadstorage.h"
#include "asterisk/slinfactory.h"
#include "asterisk/audiohook.h"
#include "asterisk/timing.h"
#include "asterisk/autochan.h"
#include "asterisk/stringfields.h"

#ifdef HAVE_EPOLL
#include <sys/epoll.h>
#endif

struct ast_epoll_data {
        struct ast_channel *chan;
        int which;
};

/* uncomment if you have problems with 'monitoring' synchronized files */
#if 0
#define MONITOR_CONSTANT_DELAY
#define MONITOR_DELAY   150 * 8         /*!< 150 ms of MONITORING DELAY */
#endif

/*! \brief Prevent new channel allocation if shutting down. */
static int shutting_down;

static int uniqueint;

unsigned long global_fin, global_fout;

AST_THREADSTORAGE(state2str_threadbuf);
#define STATE2STR_BUFSIZE   32

/*! Default amount of time to use when emulating a digit as a begin and end 
 *  100ms */
#define AST_DEFAULT_EMULATE_DTMF_DURATION 100

/*! Minimum allowed digit length - 80ms */
#define AST_MIN_DTMF_DURATION 80

/*! Minimum amount of time between the end of the last digit and the beginning 
 *  of a new one - 45ms */
#define AST_MIN_DTMF_GAP 45

/*! \brief List of channel drivers */
struct chanlist {
        const struct ast_channel_tech *tech;
        AST_LIST_ENTRY(chanlist) list;
};

#ifdef CHANNEL_TRACE
/*! \brief Structure to hold channel context backtrace data */
struct ast_chan_trace_data {
        int enabled;
        AST_LIST_HEAD_NOLOCK(, ast_chan_trace) trace;
};

/*! \brief Structure to save contexts where an ast_chan has been into */
struct ast_chan_trace {
        char context[AST_MAX_CONTEXT];
        char exten[AST_MAX_EXTENSION];
        int priority;
        AST_LIST_ENTRY(ast_chan_trace) entry;
};
#endif

/*! \brief the list of registered channel types */
static AST_RWLIST_HEAD_STATIC(backends, chanlist);

#ifdef LOW_MEMORY
#define NUM_CHANNEL_BUCKETS 61
#else
#define NUM_CHANNEL_BUCKETS 1567
#endif

/*! \brief All active channels on the system */
static struct ao2_container *channels;

/*! \brief map AST_CAUSE's to readable string representations 
 *
 * \ref causes.h
*/
static const struct {
        int cause;
        const char *name;
        const char *desc;
} causes[] = {
        { AST_CAUSE_UNALLOCATED, "UNALLOCATED", "Unallocated (unassigned) number" },
        { AST_CAUSE_NO_ROUTE_TRANSIT_NET, "NO_ROUTE_TRANSIT_NET", "No route to specified transmit network" },
        { AST_CAUSE_NO_ROUTE_DESTINATION, "NO_ROUTE_DESTINATION", "No route to destination" },
        { AST_CAUSE_CHANNEL_UNACCEPTABLE, "CHANNEL_UNACCEPTABLE", "Channel unacceptable" },
        { AST_CAUSE_CALL_AWARDED_DELIVERED, "CALL_AWARDED_DELIVERED", "Call awarded and being delivered in an established channel" },
        { AST_CAUSE_NORMAL_CLEARING, "NORMAL_CLEARING", "Normal Clearing" },
        { AST_CAUSE_USER_BUSY, "USER_BUSY", "User busy" },
        { AST_CAUSE_NO_USER_RESPONSE, "NO_USER_RESPONSE", "No user responding" },
        { AST_CAUSE_NO_ANSWER, "NO_ANSWER", "User alerting, no answer" },
        { AST_CAUSE_CALL_REJECTED, "CALL_REJECTED", "Call Rejected" },
        { AST_CAUSE_NUMBER_CHANGED, "NUMBER_CHANGED", "Number changed" },
        { AST_CAUSE_DESTINATION_OUT_OF_ORDER, "DESTINATION_OUT_OF_ORDER", "Destination out of order" },
        { AST_CAUSE_INVALID_NUMBER_FORMAT, "INVALID_NUMBER_FORMAT", "Invalid number format" },
        { AST_CAUSE_FACILITY_REJECTED, "FACILITY_REJECTED", "Facility rejected" },
        { AST_CAUSE_RESPONSE_TO_STATUS_ENQUIRY, "RESPONSE_TO_STATUS_ENQUIRY", "Response to STATus ENQuiry" },
        { AST_CAUSE_NORMAL_UNSPECIFIED, "NORMAL_UNSPECIFIED", "Normal, unspecified" },
        { AST_CAUSE_NORMAL_CIRCUIT_CONGESTION, "NORMAL_CIRCUIT_CONGESTION", "Circuit/channel congestion" },
        { AST_CAUSE_NETWORK_OUT_OF_ORDER, "NETWORK_OUT_OF_ORDER", "Network out of order" },
        { AST_CAUSE_NORMAL_TEMPORARY_FAILURE, "NORMAL_TEMPORARY_FAILURE", "Temporary failure" },
        { AST_CAUSE_SWITCH_CONGESTION, "SWITCH_CONGESTION", "Switching equipment congestion" },
        { AST_CAUSE_ACCESS_INFO_DISCARDED, "ACCESS_INFO_DISCARDED", "Access information discarded" },
        { AST_CAUSE_REQUESTED_CHAN_UNAVAIL, "REQUESTED_CHAN_UNAVAIL", "Requested channel not available" },
        { AST_CAUSE_PRE_EMPTED, "PRE_EMPTED", "Pre-empted" },
        { AST_CAUSE_FACILITY_NOT_SUBSCRIBED, "FACILITY_NOT_SUBSCRIBED", "Facility not subscribed" },
        { AST_CAUSE_OUTGOING_CALL_BARRED, "OUTGOING_CALL_BARRED", "Outgoing call barred" },
        { AST_CAUSE_INCOMING_CALL_BARRED, "INCOMING_CALL_BARRED", "Incoming call barred" },
        { AST_CAUSE_BEARERCAPABILITY_NOTAUTH, "BEARERCAPABILITY_NOTAUTH", "Bearer capability not authorized" },
        { AST_CAUSE_BEARERCAPABILITY_NOTAVAIL, "BEARERCAPABILITY_NOTAVAIL", "Bearer capability not available" },
        { AST_CAUSE_BEARERCAPABILITY_NOTIMPL, "BEARERCAPABILITY_NOTIMPL", "Bearer capability not implemented" },
        { AST_CAUSE_CHAN_NOT_IMPLEMENTED, "CHAN_NOT_IMPLEMENTED", "Channel not implemented" },
        { AST_CAUSE_FACILITY_NOT_IMPLEMENTED, "FACILITY_NOT_IMPLEMENTED", "Facility not implemented" },
        { AST_CAUSE_INVALID_CALL_REFERENCE, "INVALID_CALL_REFERENCE", "Invalid call reference value" },
        { AST_CAUSE_INCOMPATIBLE_DESTINATION, "INCOMPATIBLE_DESTINATION", "Incompatible destination" },
        { AST_CAUSE_INVALID_MSG_UNSPECIFIED, "INVALID_MSG_UNSPECIFIED", "Invalid message unspecified" },
        { AST_CAUSE_MANDATORY_IE_MISSING, "MANDATORY_IE_MISSING", "Mandatory information element is missing" },
        { AST_CAUSE_MESSAGE_TYPE_NONEXIST, "MESSAGE_TYPE_NONEXIST", "Message type nonexist." },
        { AST_CAUSE_WRONG_MESSAGE, "WRONG_MESSAGE", "Wrong message" },
        { AST_CAUSE_IE_NONEXIST, "IE_NONEXIST", "Info. element nonexist or not implemented" },
        { AST_CAUSE_INVALID_IE_CONTENTS, "INVALID_IE_CONTENTS", "Invalid information element contents" },
        { AST_CAUSE_WRONG_CALL_STATE, "WRONG_CALL_STATE", "Message not compatible with call state" },
        { AST_CAUSE_RECOVERY_ON_TIMER_EXPIRE, "RECOVERY_ON_TIMER_EXPIRE", "Recover on timer expiry" },
        { AST_CAUSE_MANDATORY_IE_LENGTH_ERROR, "MANDATORY_IE_LENGTH_ERROR", "Mandatory IE length error" },
        { AST_CAUSE_PROTOCOL_ERROR, "PROTOCOL_ERROR", "Protocol error, unspecified" },
        { AST_CAUSE_INTERWORKING, "INTERWORKING", "Interworking, unspecified" },
};

struct ast_variable *ast_channeltype_list(void)
{
        struct chanlist *cl;
        struct ast_variable *var = NULL, *prev = NULL;

        AST_RWLIST_RDLOCK(&backends);
        AST_RWLIST_TRAVERSE(&backends, cl, list) {
                if (prev)  {
                        if ((prev->next = ast_variable_new(cl->tech->type, cl->tech->description, "")))
                                prev = prev->next;
                } else {
                        var = ast_variable_new(cl->tech->type, cl->tech->description, "");
                        prev = var;
                }
        }
        AST_RWLIST_UNLOCK(&backends);

        return var;
}

/*! \brief Show channel types - CLI command */
static char *handle_cli_core_show_channeltypes(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
{
#define FORMAT  "%-10.10s  %-40.40s %-12.12s %-12.12s %-12.12s\n"
        struct chanlist *cl;
        int count_chan = 0;

        switch (cmd) {
        case CLI_INIT:
                e->command = "core show channeltypes";
                e->usage =
                        "Usage: core show channeltypes\n"
                        "       Lists available channel types registered in your\n"
                        "       Asterisk server.\n";
                return NULL;
        case CLI_GENERATE:
                return NULL;
        }

        if (a->argc != 3)
                return CLI_SHOWUSAGE;

        ast_cli(a->fd, FORMAT, "Type", "Description",       "Devicestate", "Indications", "Transfer");
        ast_cli(a->fd, FORMAT, "----------", "-----------", "-----------", "-----------", "--------");

        AST_RWLIST_RDLOCK(&backends);
        AST_RWLIST_TRAVERSE(&backends, cl, list) {
                ast_cli(a->fd, FORMAT, cl->tech->type, cl->tech->description,
                        (cl->tech->devicestate) ? "yes" : "no",
                        (cl->tech->indicate) ? "yes" : "no",
                        (cl->tech->transfer) ? "yes" : "no");
                count_chan++;
        }
        AST_RWLIST_UNLOCK(&backends);

        ast_cli(a->fd, "----------\n%d channel drivers registered.\n", count_chan);

        return CLI_SUCCESS;

#undef FORMAT
}

static char *complete_channeltypes(struct ast_cli_args *a)
{
        struct chanlist *cl;
        int which = 0;
        int wordlen;
        char *ret = NULL;

        if (a->pos != 3)
                return NULL;

        wordlen = strlen(a->word);

        AST_RWLIST_RDLOCK(&backends);
        AST_RWLIST_TRAVERSE(&backends, cl, list) {
                if (!strncasecmp(a->word, cl->tech->type, wordlen) && ++which > a->n) {
                        ret = ast_strdup(cl->tech->type);
                        break;
                }
        }
        AST_RWLIST_UNLOCK(&backends);
        
        return ret;
}

/*! \brief Show details about a channel driver - CLI command */
static char *handle_cli_core_show_channeltype(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
{
        struct chanlist *cl = NULL;
        char buf[512];

        switch (cmd) {
        case CLI_INIT:
                e->command = "core show channeltype";
                e->usage =
                        "Usage: core show channeltype <name>\n"
                        "       Show details about the specified channel type, <name>.\n";
                return NULL;
        case CLI_GENERATE:
                return complete_channeltypes(a);
        }

        if (a->argc != 4)
                return CLI_SHOWUSAGE;
        
        AST_RWLIST_RDLOCK(&backends);

        AST_RWLIST_TRAVERSE(&backends, cl, list) {
                if (!strncasecmp(cl->tech->type, a->argv[3], strlen(cl->tech->type)))
                        break;
        }


        if (!cl) {
                ast_cli(a->fd, "\n%s is not a registered channel driver.\n", a->argv[3]);
                AST_RWLIST_UNLOCK(&backends);
                return CLI_FAILURE;
        }

        ast_cli(a->fd,
                "-- Info about channel driver: %s --\n"
                "  Device State: %s\n"
                "    Indication: %s\n"
                "     Transfer : %s\n"
                "  Capabilities: %s\n"
                "   Digit Begin: %s\n"
                "     Digit End: %s\n"
                "    Send HTML : %s\n"
                " Image Support: %s\n"
                "  Text Support: %s\n",
                cl->tech->type,
                (cl->tech->devicestate) ? "yes" : "no",
                (cl->tech->indicate) ? "yes" : "no",
                (cl->tech->transfer) ? "yes" : "no",
                ast_getformatname_multiple(buf, sizeof(buf), (cl->tech->capabilities) ? cl->tech->capabilities : -1),
                (cl->tech->send_digit_begin) ? "yes" : "no",
                (cl->tech->send_digit_end) ? "yes" : "no",
                (cl->tech->send_html) ? "yes" : "no",
                (cl->tech->send_image) ? "yes" : "no",
                (cl->tech->send_text) ? "yes" : "no"
                
        );

        AST_RWLIST_UNLOCK(&backends);

        return CLI_SUCCESS;
}

static struct ast_cli_entry cli_channel[] = {
        AST_CLI_DEFINE(handle_cli_core_show_channeltypes, "List available channel types"),
        AST_CLI_DEFINE(handle_cli_core_show_channeltype,  "Give more details on that channel type")
};

#ifdef CHANNEL_TRACE
/*! \brief Destructor for the channel trace datastore */
static void ast_chan_trace_destroy_cb(void *data)
{
        struct ast_chan_trace *trace;
        struct ast_chan_trace_data *traced = data;
        while ((trace = AST_LIST_REMOVE_HEAD(&traced->trace, entry))) {
                ast_free(trace);
        }
        ast_free(traced);
}

/*! \brief Datastore to put the linked list of ast_chan_trace and trace status */
static const struct ast_datastore_info ast_chan_trace_datastore_info = {
        .type = "ChanTrace",
        .destroy = ast_chan_trace_destroy_cb
};

/*! \brief Put the channel backtrace in a string */
int ast_channel_trace_serialize(struct ast_channel *chan, struct ast_str **buf)
{
        int total = 0;
        struct ast_chan_trace *trace;
        struct ast_chan_trace_data *traced;
        struct ast_datastore *store;

        ast_channel_lock(chan);
        store = ast_channel_datastore_find(chan, &ast_chan_trace_datastore_info, NULL);
        if (!store) {
                ast_channel_unlock(chan);
                return total;
        }
        traced = store->data;
        ast_str_reset(*buf);
        AST_LIST_TRAVERSE(&traced->trace, trace, entry) {
                if (ast_str_append(buf, 0, "[%d] => %s, %s, %d\n", total, trace->context, trace->exten, trace->priority) < 0) {
                        ast_log(LOG_ERROR, "Data Buffer Size Exceeded!\n");
                        total = -1;
                        break;
                }
                total++;
        }
        ast_channel_unlock(chan);
        return total;
}

/* !\brief Whether or not context tracing is enabled */
int ast_channel_trace_is_enabled(struct ast_channel *chan)
{
        struct ast_datastore *store = ast_channel_datastore_find(chan, &ast_chan_trace_datastore_info, NULL);
        if (!store)
                return 0;
        return ((struct ast_chan_trace_data *)store->data)->enabled;
}

/*! \brief Update the context backtrace data if tracing is enabled */
static int ast_channel_trace_data_update(struct ast_channel *chan, struct ast_chan_trace_data *traced)
{
        struct ast_chan_trace *trace;
        if (!traced->enabled)
                return 0;
        /* If the last saved context does not match the current one
           OR we have not saved any context so far, then save the current context */
        if ((!AST_LIST_EMPTY(&traced->trace) && strcasecmp(AST_LIST_FIRST(&traced->trace)->context, chan->context)) || 
            (AST_LIST_EMPTY(&traced->trace))) {
                /* Just do some debug logging */
                if (AST_LIST_EMPTY(&traced->trace))
                        ast_log(LOG_DEBUG, "Setting initial trace context to %s\n", chan->context);
                else
                        ast_log(LOG_DEBUG, "Changing trace context from %s to %s\n", AST_LIST_FIRST(&traced->trace)->context, chan->context);
                /* alloc or bail out */
                trace = ast_malloc(sizeof(*trace));
                if (!trace) 
                        return -1;
                /* save the current location and store it in the trace list */
                ast_copy_string(trace->context, chan->context, sizeof(trace->context));
                ast_copy_string(trace->exten, chan->exten, sizeof(trace->exten));
                trace->priority = chan->priority;
                AST_LIST_INSERT_HEAD(&traced->trace, trace, entry);
        }
        return 0;
}

/*! \brief Update the context backtrace if tracing is enabled */
int ast_channel_trace_update(struct ast_channel *chan)
{
        struct ast_datastore *store = ast_channel_datastore_find(chan, &ast_chan_trace_datastore_info, NULL);
        if (!store)
                return 0;
        return ast_channel_trace_data_update(chan, store->data);
}

/*! \brief Enable context tracing in the channel */
int ast_channel_trace_enable(struct ast_channel *chan)
{
        struct ast_datastore *store = ast_channel_datastore_find(chan, &ast_chan_trace_datastore_info, NULL);
        struct ast_chan_trace_data *traced;
        if (!store) {
                store = ast_datastore_alloc(&ast_chan_trace_datastore_info, "ChanTrace");
                if (!store) 
                        return -1;
                traced = ast_calloc(1, sizeof(*traced));
                if (!traced) {
                        ast_datastore_free(store);
                        return -1;
                }       
                store->data = traced;
                AST_LIST_HEAD_INIT_NOLOCK(&traced->trace);
                ast_channel_datastore_add(chan, store);
        }       
        ((struct ast_chan_trace_data *)store->data)->enabled = 1;
        ast_channel_trace_data_update(chan, store->data);
        return 0;
}

/*! \brief Disable context tracing in the channel */
int ast_channel_trace_disable(struct ast_channel *chan)
{
        struct ast_datastore *store = ast_channel_datastore_find(chan, &ast_chan_trace_datastore_info, NULL);
        if (!store)
                return 0;
        ((struct ast_chan_trace_data *)store->data)->enabled = 0;
        return 0;
}
#endif /* CHANNEL_TRACE */

/*! \brief Checks to see if a channel is needing hang up */
int ast_check_hangup(struct ast_channel *chan)
{
        if (chan->_softhangup)          /* yes if soft hangup flag set */
                return 1;
        if (ast_tvzero(chan->whentohangup))     /* no if no hangup scheduled */
                return 0;
        if (ast_tvdiff_ms(chan->whentohangup, ast_tvnow()) > 0)         /* no if hangup time has not come yet. */
                return 0;
        chan->_softhangup |= AST_SOFTHANGUP_TIMEOUT;    /* record event */
        return 1;
}

int ast_check_hangup_locked(struct ast_channel *chan)
{
        int res;
        ast_channel_lock(chan);
        res = ast_check_hangup(chan);
        ast_channel_unlock(chan);
        return res;
}

static int ast_channel_softhangup_cb(void *obj, void *arg, int flags)
{
        struct ast_channel *chan = obj;

        ast_softhangup(chan, AST_SOFTHANGUP_SHUTDOWN);

        return 0;
}

void ast_begin_shutdown(int hangup)
{
        shutting_down = 1;

        if (hangup) {
                ao2_callback(channels, OBJ_NODATA | OBJ_MULTIPLE, ast_channel_softhangup_cb, NULL);
        }
}

/*! \brief returns number of active/allocated channels */
int ast_active_channels(void)
{
        return channels ? ao2_container_count(channels) : 0;
}

/*! \brief Cancel a shutdown in progress */
void ast_cancel_shutdown(void)
{
        shutting_down = 0;
}

/*! \brief Returns non-zero if Asterisk is being shut down */
int ast_shutting_down(void)
{
        return shutting_down;
}

/*! \brief Set when to hangup channel */
void ast_channel_setwhentohangup_tv(struct ast_channel *chan, struct timeval offset)
{
        chan->whentohangup = ast_tvzero(offset) ? offset : ast_tvadd(offset, ast_tvnow());
        ast_queue_frame(chan, &ast_null_frame);
        return;
}

void ast_channel_setwhentohangup(struct ast_channel *chan, time_t offset)
{
        struct timeval when = { offset, };
        ast_channel_setwhentohangup_tv(chan, when);
}

/*! \brief Compare a offset with when to hangup channel */
int ast_channel_cmpwhentohangup_tv(struct ast_channel *chan, struct timeval offset)
{
        struct timeval whentohangup;

        if (ast_tvzero(chan->whentohangup))
                return ast_tvzero(offset) ? 0 : -1;

        if (ast_tvzero(offset))
                return 1;

        whentohangup = ast_tvadd(offset, ast_tvnow());

        return ast_tvdiff_ms(whentohangup, chan->whentohangup);
}

int ast_channel_cmpwhentohangup(struct ast_channel *chan, time_t offset)
{
        struct timeval when = { offset, };
        return ast_channel_cmpwhentohangup_tv(chan, when);
}

/*! \brief Register a new telephony channel in Asterisk */
int ast_channel_register(const struct ast_channel_tech *tech)
{
        struct chanlist *chan;

        AST_RWLIST_WRLOCK(&backends);

        AST_RWLIST_TRAVERSE(&backends, chan, list) {
                if (!strcasecmp(tech->type, chan->tech->type)) {
                        ast_log(LOG_WARNING, "Already have a handler for type '%s'\n", tech->type);
                        AST_RWLIST_UNLOCK(&backends);
                        return -1;
                }
        }
        
        if (!(chan = ast_calloc(1, sizeof(*chan)))) {
                AST_RWLIST_UNLOCK(&backends);
                return -1;
        }
        chan->tech = tech;
        AST_RWLIST_INSERT_HEAD(&backends, chan, list);

        ast_debug(1, "Registered handler for '%s' (%s)\n", chan->tech->type, chan->tech->description);

        ast_verb(2, "Registered channel type '%s' (%s)\n", chan->tech->type, chan->tech->description);

        AST_RWLIST_UNLOCK(&backends);

        return 0;
}

/*! \brief Unregister channel driver */
void ast_channel_unregister(const struct ast_channel_tech *tech)
{
        struct chanlist *chan;

        ast_debug(1, "Unregistering channel type '%s'\n", tech->type);

        AST_RWLIST_WRLOCK(&backends);

        AST_RWLIST_TRAVERSE_SAFE_BEGIN(&backends, chan, list) {
                if (chan->tech == tech) {
                        AST_LIST_REMOVE_CURRENT(list);
                        ast_free(chan);
                        ast_verb(2, "Unregistered channel type '%s'\n", tech->type);
                        break;  
                }
        }
        AST_LIST_TRAVERSE_SAFE_END;

        AST_RWLIST_UNLOCK(&backends);
}

/*! \brief Get handle to channel driver based on name */
const struct ast_channel_tech *ast_get_channel_tech(const char *name)
{
        struct chanlist *chanls;
        const struct ast_channel_tech *ret = NULL;

        AST_RWLIST_RDLOCK(&backends);

        AST_RWLIST_TRAVERSE(&backends, chanls, list) {
                if (!strcasecmp(name, chanls->tech->type)) {
                        ret = chanls->tech;
                        break;
                }
        }

        AST_RWLIST_UNLOCK(&backends);
        
        return ret;
}

/*! \brief Gives the string form of a given hangup cause */
const char *ast_cause2str(int cause)
{
        int x;

        for (x = 0; x < ARRAY_LEN(causes); x++) {
                if (causes[x].cause == cause)
                        return causes[x].desc;
        }

        return "Unknown";
}

/*! \brief Convert a symbolic hangup cause to number */
int ast_str2cause(const char *name)
{
        int x;

        for (x = 0; x < ARRAY_LEN(causes); x++)
                if (!strncasecmp(causes[x].name, name, strlen(causes[x].name)))
                        return causes[x].cause;

        return -1;
}

/*! \brief Gives the string form of a given channel state.
        \note This function is not reentrant.
 */
const char *ast_state2str(enum ast_channel_state state)
{
        char *buf;

        switch (state) {
        case AST_STATE_DOWN:
                return "Down";
        case AST_STATE_RESERVED:
                return "Rsrvd";
        case AST_STATE_OFFHOOK:
                return "OffHook";
        case AST_STATE_DIALING:
                return "Dialing";
        case AST_STATE_RING:
                return "Ring";
        case AST_STATE_RINGING:
                return "Ringing";
        case AST_STATE_UP:
                return "Up";
        case AST_STATE_BUSY:
                return "Busy";
        case AST_STATE_DIALING_OFFHOOK:
                return "Dialing Offhook";
        case AST_STATE_PRERING:
                return "Pre-ring";
        default:
                if (!(buf = ast_threadstorage_get(&state2str_threadbuf, STATE2STR_BUFSIZE)))
                        return "Unknown";
                snprintf(buf, STATE2STR_BUFSIZE, "Unknown (%d)", state);
                return buf;
        }
}

/*! \brief Gives the string form of a given transfer capability */
char *ast_transfercapability2str(int transfercapability)
{
        switch (transfercapability) {
        case AST_TRANS_CAP_SPEECH:
                return "SPEECH";
        case AST_TRANS_CAP_DIGITAL:
                return "DIGITAL";
        case AST_TRANS_CAP_RESTRICTED_DIGITAL:
                return "RESTRICTED_DIGITAL";
        case AST_TRANS_CAP_3_1K_AUDIO:
                return "3K1AUDIO";
        case AST_TRANS_CAP_DIGITAL_W_TONES:
                return "DIGITAL_W_TONES";
        case AST_TRANS_CAP_VIDEO:
                return "VIDEO";
        default:
                return "UNKNOWN";
        }
}

/*! \brief Pick the best audio codec */
format_t ast_best_codec(format_t fmts)
{
        /* This just our opinion, expressed in code.  We are asked to choose
           the best codec to use, given no information */
        int x;
        static const format_t prefs[] =
        {
                /*! Okay, ulaw is used by all telephony equipment, so start with it */
                AST_FORMAT_ULAW,
                /*! Unless of course, you're a silly European, so then prefer ALAW */
                AST_FORMAT_ALAW,
                AST_FORMAT_SIREN14,
                AST_FORMAT_SIREN7,
                AST_FORMAT_TESTLAW,
                /*! G.722 is better then all below, but not as common as the above... so give ulaw and alaw priority */
                AST_FORMAT_G722,
                /*! Okay, well, signed linear is easy to translate into other stuff */
                AST_FORMAT_SLINEAR16,
                AST_FORMAT_SLINEAR,
                /*! G.726 is standard ADPCM, in RFC3551 packing order */
                AST_FORMAT_G726,
                /*! G.726 is standard ADPCM, in AAL2 packing order */
                AST_FORMAT_G726_AAL2,
                /*! ADPCM has great sound quality and is still pretty easy to translate */
                AST_FORMAT_ADPCM,
                /*! Okay, we're down to vocoders now, so pick GSM because it's small and easier to
                    translate and sounds pretty good */
                AST_FORMAT_GSM,
                /*! iLBC is not too bad */
                AST_FORMAT_ILBC,
                /*! Speex is free, but computationally more expensive than GSM */
                AST_FORMAT_SPEEX,
                /*! Ick, LPC10 sounds terrible, but at least we have code for it, if you're tacky enough
                    to use it */
                AST_FORMAT_LPC10,
                /*! G.729a is faster than 723 and slightly less expensive */
                AST_FORMAT_G729A,
                /*! Down to G.723.1 which is proprietary but at least designed for voice */
                AST_FORMAT_G723_1,
        };
        char buf[512];

        /* Strip out video */
        fmts &= AST_FORMAT_AUDIO_MASK;
        
        /* Find the first preferred codec in the format given */
        for (x = 0; x < ARRAY_LEN(prefs); x++) {
                if (fmts & prefs[x])
                        return prefs[x];
        }

        ast_log(LOG_WARNING, "Don't know any of %s formats\n", ast_getformatname_multiple(buf, sizeof(buf), fmts));

        return 0;
}

static const struct ast_channel_tech null_tech = {
        .type = "NULL",
        .description = "Null channel (should not see this)",
};

static void ast_channel_destructor(void *obj);
static void ast_dummy_channel_destructor(void *obj);

/*! \brief Create a new channel structure */
static struct ast_channel * attribute_malloc __attribute__((format(printf, 13, 0)))
__ast_channel_alloc_ap(int needqueue, int state, const char *cid_num, const char *cid_name,
                       const char *acctcode, const char *exten, const char *context,
                       const char *linkedid, const int amaflag, const char *file, int line,
                       const char *function, const char *name_fmt, va_list ap1, va_list ap2)
{
        struct ast_channel *tmp;
        int x;
        int flags;
        struct varshead *headp;

        /* If shutting down, don't allocate any new channels */
        if (shutting_down) {
                ast_log(LOG_WARNING, "Channel allocation failed: Refusing due to active shutdown\n");
                return NULL;
        }

#if defined(REF_DEBUG)
        if (!(tmp = __ao2_alloc_debug(sizeof(*tmp), ast_channel_destructor, "", file, line, function, 1))) {
                return NULL;
        }
#elif defined(__AST_DEBUG_MALLOC)
        if (!(tmp = __ao2_alloc_debug(sizeof(*tmp), ast_channel_destructor, "", file, line, function, 0))) {
                return NULL;
        }
#else
        if (!(tmp = ao2_alloc(sizeof(*tmp), ast_channel_destructor))) {
                return NULL;
        }
#endif

        if (!(tmp->sched = sched_context_create())) {
                ast_log(LOG_WARNING, "Channel allocation failed: Unable to create schedule context\n");
                return ast_channel_unref(tmp);
        }
        
        if ((ast_string_field_init(tmp, 128))) {
                return ast_channel_unref(tmp);
        }

        if (cid_name) {
                if (!(tmp->cid.cid_name = ast_strdup(cid_name))) {
                        return ast_channel_unref(tmp);
                }
        }
        if (cid_num) {
                if (!(tmp->cid.cid_num = ast_strdup(cid_num))) {
                        return ast_channel_unref(tmp);
                }
        }

#ifdef HAVE_EPOLL
        tmp->epfd = epoll_create(25);
#endif

        for (x = 0; x < AST_MAX_FDS; x++) {
                tmp->fds[x] = -1;
#ifdef HAVE_EPOLL
                tmp->epfd_data[x] = NULL;
#endif
        }

        if ((tmp->timer = ast_timer_open())) {
                needqueue = 0;
                tmp->timingfd = ast_timer_fd(tmp->timer);
        } else {
                tmp->timingfd = -1;
        }

        if (needqueue) {
                if (pipe(tmp->alertpipe)) {
                        ast_log(LOG_WARNING, "Channel allocation failed: Can't create alert pipe! Try increasing max file descriptors with ulimit -n\n");
alertpipe_failed:
                        if (tmp->timer) {
                                ast_timer_close(tmp->timer);
                        }

                        sched_context_destroy(tmp->sched);
                        ast_string_field_free_memory(tmp);
                        ast_free(tmp->cid.cid_name);
                        ast_free(tmp->cid.cid_num);
                        ast_free(tmp);
                        return NULL;
                } else {
                        flags = fcntl(tmp->alertpipe[0], F_GETFL);
                        if (fcntl(tmp->alertpipe[0], F_SETFL, flags | O_NONBLOCK) < 0) {
                                ast_log(LOG_WARNING, "Channel allocation failed: Unable to set alertpipe nonblocking! (%d: %s)\n", errno, strerror(errno));
                                close(tmp->alertpipe[0]);
                                close(tmp->alertpipe[1]);
                                goto alertpipe_failed;
                        }
                        flags = fcntl(tmp->alertpipe[1], F_GETFL);
                        if (fcntl(tmp->alertpipe[1], F_SETFL, flags | O_NONBLOCK) < 0) {
                                ast_log(LOG_WARNING, "Channel allocation failed: Unable to set alertpipe nonblocking! (%d: %s)\n", errno, strerror(errno));
                                close(tmp->alertpipe[0]);
                                close(tmp->alertpipe[1]);
                                goto alertpipe_failed;
                        }
                }
        } else  /* Make sure we've got it done right if they don't */
                tmp->alertpipe[0] = tmp->alertpipe[1] = -1;

        /* Always watch the alertpipe */
        ast_channel_set_fd(tmp, AST_ALERT_FD, tmp->alertpipe[0]);
        /* And timing pipe */
        ast_channel_set_fd(tmp, AST_TIMING_FD, tmp->timingfd);
        ast_string_field_set(tmp, name, "**Unknown**");

        /* Initial state */
        tmp->_state = state;

        tmp->streamid = -1;
        
        tmp->fin = global_fin;
        tmp->fout = global_fout;

        if (ast_strlen_zero(ast_config_AST_SYSTEM_NAME)) {
                ast_string_field_build(tmp, uniqueid, "%li.%d", (long) time(NULL), 
                                       ast_atomic_fetchadd_int(&uniqueint, 1));
        } else {
                ast_string_field_build(tmp, uniqueid, "%s-%li.%d", ast_config_AST_SYSTEM_NAME, 
                                       (long) time(NULL), ast_atomic_fetchadd_int(&uniqueint, 1));
        }

        if (!ast_strlen_zero(linkedid)) {
                ast_string_field_set(tmp, linkedid, linkedid);
        }
        else {
                ast_string_field_set(tmp, linkedid, tmp->uniqueid);
        }

        if (!ast_strlen_zero(name_fmt)) {
                /* Almost every channel is calling this function, and setting the name via the ast_string_field_build() call.
                 * And they all use slightly different formats for their name string.
                 * This means, to set the name here, we have to accept variable args, and call the string_field_build from here.
                 * This means, that the stringfields must have a routine that takes the va_lists directly, and 
                 * uses them to build the string, instead of forming the va_lists internally from the vararg ... list.
                 * This new function was written so this can be accomplished.
                 */
                ast_string_field_build_va(tmp, name, name_fmt, ap1, ap2);
        }

        /* Reminder for the future: under what conditions do we NOT want to track cdrs on channels? */

        /* These 4 variables need to be set up for the cdr_init() to work right */
        if (amaflag)
                tmp->amaflags = amaflag;
        else
                tmp->amaflags = ast_default_amaflags;
        
        if (!ast_strlen_zero(acctcode))
                ast_string_field_set(tmp, accountcode, acctcode);
        else
                ast_string_field_set(tmp, accountcode, ast_default_accountcode);
                
        if (!ast_strlen_zero(context))
                ast_copy_string(tmp->context, context, sizeof(tmp->context));
        else
                strcpy(tmp->context, "default");

        if (!ast_strlen_zero(exten))
                ast_copy_string(tmp->exten, exten, sizeof(tmp->exten));
        else
                strcpy(tmp->exten, "s");

        tmp->priority = 1;

        tmp->cdr = ast_cdr_alloc();
        ast_cdr_init(tmp->cdr, tmp);
        ast_cdr_start(tmp->cdr);

        ast_cel_report_event(tmp, AST_CEL_CHANNEL_START, NULL, NULL, NULL);

        headp = &tmp->varshead;
        AST_LIST_HEAD_INIT_NOLOCK(headp);
        
        AST_LIST_HEAD_INIT_NOLOCK(&tmp->datastores);

        AST_LIST_HEAD_INIT_NOLOCK(&tmp->autochans);
        
        ast_string_field_set(tmp, language, defaultlanguage);

        tmp->tech = &null_tech;

        ao2_link(channels, tmp);

        /*\!note
         * and now, since the channel structure is built, and has its name, let's
         * call the manager event generator with this Newchannel event. This is the
         * proper and correct place to make this call, but you sure do have to pass
         * a lot of data into this func to do it here!
         */
        if (!ast_strlen_zero(name_fmt)) {
                ast_manager_event(tmp, EVENT_FLAG_CALL, "Newchannel",
                        "Channel: %s\r\n"
                        "ChannelState: %d\r\n"
                        "ChannelStateDesc: %s\r\n"
                        "CallerIDNum: %s\r\n"
                        "CallerIDName: %s\r\n"
                        "AccountCode: %s\r\n"
                        "Exten: %s\r\n"
                        "Context: %s\r\n"
                        "Uniqueid: %s\r\n",
                        tmp->name, 
                        state, 
                        ast_state2str(state),
                        S_OR(cid_num, ""),
                        S_OR(cid_name, ""),
                        tmp->accountcode,
                        S_OR(exten, ""),
                        S_OR(context, ""),
                        tmp->uniqueid);
        }

        return tmp;
}

struct ast_channel *__ast_channel_alloc(int needqueue, int state, const char *cid_num,
                                        const char *cid_name, const char *acctcode,
                                        const char *exten, const char *context,
                                        const char *linkedid, const int amaflag,
                                        const char *file, int line, const char *function,
                                        const char *name_fmt, ...)
{
        va_list ap1, ap2;
        struct ast_channel *result;

        va_start(ap1, name_fmt);
        va_start(ap2, name_fmt);
        result = __ast_channel_alloc_ap(needqueue, state, cid_num, cid_name, acctcode, exten, context,
                                        linkedid, amaflag, file, line, function, name_fmt, ap1, ap2);
        va_end(ap1);
        va_end(ap2);

        return result;
}

/* only do the minimum amount of work needed here to make a channel
 * structure that can be used to expand channel vars */
#if defined(REF_DEBUG) || defined(__AST_DEBUG_MALLOC)
struct ast_channel *__ast_dummy_channel_alloc(const char *file, int line, const char *function)
#else
struct ast_channel *ast_dummy_channel_alloc(void)
#endif
{
        struct ast_channel *tmp;
        struct varshead *headp;

#if defined(REF_DEBUG)
        if (!(tmp = __ao2_alloc_debug(sizeof(*tmp), ast_dummy_channel_destructor, "dummy channel", file, line, function, 1))) {
                return NULL;
        }
#elif defined(__AST_DEBUG_MALLOC)
        if (!(tmp = __ao2_alloc_debug(sizeof(*tmp), ast_dummy_channel_destructor, "dummy channel", file, line, function, 0))) {
                return NULL;
        }
#else
        if (!(tmp = ao2_alloc(sizeof(*tmp), ast_dummy_channel_destructor))) {
                return NULL;
        }
#endif

        if ((ast_string_field_init(tmp, 128))) {
                ast_channel_unref(tmp);
                return NULL;
        }

        headp = &tmp->varshead;
        AST_LIST_HEAD_INIT_NOLOCK(headp);

        return tmp;
}

static int __ast_queue_frame(struct ast_channel *chan, struct ast_frame *fin, int head, struct ast_frame *after)
{
        struct ast_frame *f;
        struct ast_frame *cur;
        int blah = 1;
        unsigned int new_frames = 0;
        unsigned int new_voice_frames = 0;
        unsigned int queued_frames = 0;
        unsigned int queued_voice_frames = 0;
        AST_LIST_HEAD_NOLOCK(, ast_frame) frames;

        ast_channel_lock(chan);

        /* See if the last frame on the queue is a hangup, if so don't queue anything */
        if ((cur = AST_LIST_LAST(&chan->readq)) &&
            (cur->frametype == AST_FRAME_CONTROL) &&
            (cur->subclass.integer == AST_CONTROL_HANGUP)) {
                ast_channel_unlock(chan);
                return 0;
        }

        /* Build copies of all the frames and count them */
        AST_LIST_HEAD_INIT_NOLOCK(&frames);
        for (cur = fin; cur; cur = AST_LIST_NEXT(cur, frame_list)) {
                if (!(f = ast_frdup(cur))) {
                        ast_frfree(AST_LIST_FIRST(&frames));
                        ast_channel_unlock(chan);
                        return -1;
                }

                AST_LIST_INSERT_TAIL(&frames, f, frame_list);
                new_frames++;
                if (f->frametype == AST_FRAME_VOICE) {
                        new_voice_frames++;
                }
        }

        /* Count how many frames exist on the queue */
        AST_LIST_TRAVERSE(&chan->readq, cur, frame_list) {
                queued_frames++;
                if (cur->frametype == AST_FRAME_VOICE) {
                        queued_voice_frames++;
                }
        }

        if ((queued_frames + new_frames) > 128) {
                ast_log(LOG_WARNING, "Exceptionally long queue length queuing to %s\n", chan->name);
                while ((f = AST_LIST_REMOVE_HEAD(&frames, frame_list))) {
                        ast_frfree(f);
                }
                ast_channel_unlock(chan);
                return 0;
        }

        if ((queued_voice_frames + new_voice_frames) > 96) {
                ast_log(LOG_WARNING, "Exceptionally long voice queue length queuing to %s\n", chan->name);
                while ((f = AST_LIST_REMOVE_HEAD(&frames, frame_list))) {
                        ast_frfree(f);
                }
                ast_channel_unlock(chan);
                return 0;
        }

        if (after) {
                AST_LIST_INSERT_LIST_AFTER(&chan->readq, &frames, after, frame_list);
        } else {
                if (head) {
                        AST_LIST_APPEND_LIST(&frames, &chan->readq, frame_list);
                        AST_LIST_HEAD_INIT_NOLOCK(&chan->readq);
                }
                AST_LIST_APPEND_LIST(&chan->readq, &frames, frame_list);
        }

        if (chan->alertpipe[1] > -1) {
                if (write(chan->alertpipe[1], &blah, new_frames * sizeof(blah)) != (new_frames * sizeof(blah))) {
                        ast_log(LOG_WARNING, "Unable to write to alert pipe on %s (qlen = %d): %s!\n",
                                chan->name, queued_frames, strerror(errno));
                }
        } else if (chan->timingfd > -1) {
                ast_timer_enable_continuous(chan->timer);
        } else if (ast_test_flag(chan, AST_FLAG_BLOCKING)) {
                pthread_kill(chan->blocker, SIGURG);
        }

        ast_channel_unlock(chan);

        return 0;
}

int ast_queue_frame(struct ast_channel *chan, struct ast_frame *fin)
{
        return __ast_queue_frame(chan, fin, 0, NULL);
}

int ast_queue_frame_head(struct ast_channel *chan, struct ast_frame *fin)
{
        return __ast_queue_frame(chan, fin, 1, NULL);
}

/*! \brief Queue a hangup frame for channel */
int ast_queue_hangup(struct ast_channel *chan)
{
        struct ast_frame f = { AST_FRAME_CONTROL, .subclass.integer = AST_CONTROL_HANGUP };
        /* Yeah, let's not change a lock-critical value without locking */
        if (!ast_channel_trylock(chan)) {
                chan->_softhangup |= AST_SOFTHANGUP_DEV;
                ast_channel_unlock(chan);
        }
        return ast_queue_frame(chan, &f);
}

/*! \brief Queue a hangup frame for channel */
int ast_queue_hangup_with_cause(struct ast_channel *chan, int cause)
{
        struct ast_frame f = { AST_FRAME_CONTROL, .subclass.integer = AST_CONTROL_HANGUP };

        if (cause >= 0)
                f.data.uint32 = cause;

        /* Yeah, let's not change a lock-critical value without locking */
        if (!ast_channel_trylock(chan)) {
                chan->_softhangup |= AST_SOFTHANGUP_DEV;
                if (cause < 0)
                        f.data.uint32 = chan->hangupcause;

                ast_channel_unlock(chan);
        }

        return ast_queue_frame(chan, &f);
}

/*! \brief Queue a control frame */
int ast_queue_control(struct ast_channel *chan, enum ast_control_frame_type control)
{
        struct ast_frame f = { AST_FRAME_CONTROL, .subclass.integer = control };
        return ast_queue_frame(chan, &f);
}

/*! \brief Queue a control frame with payload */
int ast_queue_control_data(struct ast_channel *chan, enum ast_control_frame_type control,
                           const void *data, size_t datalen)
{
        struct ast_frame f = { AST_FRAME_CONTROL, .subclass.integer = control, .data.ptr = (void *) data, .datalen = datalen };
        return ast_queue_frame(chan, &f);
}

/*! \brief Set defer DTMF flag on channel */
int ast_channel_defer_dtmf(struct ast_channel *chan)
{
        int pre = 0;

        if (chan) {
                pre = ast_test_flag(chan, AST_FLAG_DEFER_DTMF);
                ast_set_flag(chan, AST_FLAG_DEFER_DTMF);
        }
        return pre;
}

/*! \brief Unset defer DTMF flag on channel */
void ast_channel_undefer_dtmf(struct ast_channel *chan)
{
        if (chan)
                ast_clear_flag(chan, AST_FLAG_DEFER_DTMF);
}

struct ast_channel *ast_channel_callback(ao2_callback_data_fn *cb_fn, void *arg,
                void *data, int ao2_flags)
{
        return ao2_callback_data(channels, ao2_flags, cb_fn, arg, data);
}

struct ast_channel_iterator {
        /* storage for non-dynamically allocated iterator */
        struct ao2_iterator simple_iterator;
        /* pointer to the actual iterator (simple_iterator or a dynamically
         * allocated iterator)
         */
        struct ao2_iterator *active_iterator;
};

struct ast_channel_iterator *ast_channel_iterator_destroy(struct ast_channel_iterator *i)
{
        ao2_iterator_destroy(i->active_iterator);
        ast_free(i);

        return NULL;
}

static struct ast_channel_iterator *channel_iterator_search(const char *name,
                                                            size_t name_len, const char *exten,
                                                            const char *context)
{
        struct ast_channel_iterator *i;
        struct ast_channel tmp_chan = {
                .name = name,
                /* This is sort of a hack.  Basically, we're using an arbitrary field
                 * in ast_channel to pass the name_len for a prefix match.  If this
                 * gets changed, then the compare callback must be changed, too. */
                .rings = name_len,
        };

        if (!(i = ast_calloc(1, sizeof(*i)))) {
                return NULL;
        }

        if (exten) {
                ast_copy_string(tmp_chan.exten, exten, sizeof(tmp_chan.exten));
        }

        if (context) {
                ast_copy_string(tmp_chan.context, context, sizeof(tmp_chan.context));
        }

        if (!(i->active_iterator = ao2_find(channels, &tmp_chan,
                                            OBJ_MULTIPLE | ((!ast_strlen_zero(name) && (name_len == 0)) ? OBJ_POINTER : 0)))) {
                    ast_free(i);
                    return NULL;
        }

        return i;
}

struct ast_channel_iterator *ast_channel_iterator_by_exten_new(const char *exten, const char *context)
{
        return channel_iterator_search(NULL, 0, exten, context);
}

struct ast_channel_iterator *ast_channel_iterator_by_name_new(const char *name, size_t name_len)
{
        return channel_iterator_search(name, name_len, NULL, NULL);
}

struct ast_channel_iterator *ast_channel_iterator_all_new(void)
{
        struct ast_channel_iterator *i;

        if (!(i = ast_calloc(1, sizeof(*i)))) {
                return NULL;
        }

        i->simple_iterator = ao2_iterator_init(channels, 0);
        i->active_iterator = &i->simple_iterator;

        return i;
}

struct ast_channel *ast_channel_iterator_next(struct ast_channel_iterator *i)
{
        return ao2_iterator_next(i->active_iterator);
}

static int ast_channel_cmp_cb(void *obj, void *arg, int flags)
{
        struct ast_channel *chan = obj, *cmp_args = arg;
        size_t name_len;
        int ret = CMP_MATCH;

        /* This is sort of a hack.  Basically, we're using an arbitrary field
         * in ast_channel to pass the name_len for a prefix match.  If this
         * gets changed, then the uses of ao2_find() must be changed, too. */
        name_len = cmp_args->rings;

        ast_channel_lock(chan);

        if (!ast_strlen_zero(cmp_args->name)) { /* match by name */
                if ((!name_len && strcasecmp(chan->name, cmp_args->name)) ||
                                (name_len && strncasecmp(chan->name, cmp_args->name, name_len))) {
                        ret = 0; /* name match failed */
                }
        } else if (!ast_strlen_zero(cmp_args->exten)) {
                if (cmp_args->context && strcasecmp(chan->context, cmp_args->context) &&
                                strcasecmp(chan->macrocontext, cmp_args->context)) {
                        ret = 0; /* context match failed */
                }
                if (ret && strcasecmp(chan->exten, cmp_args->exten) &&
                                strcasecmp(chan->macroexten, cmp_args->exten)) {
                        ret = 0; /* exten match failed */
                }
        } else if (!ast_strlen_zero(cmp_args->uniqueid)) {
                if ((!name_len && strcasecmp(chan->uniqueid, cmp_args->uniqueid)) ||
                                (name_len && strncasecmp(chan->uniqueid, cmp_args->uniqueid, name_len))) {
                        ret = 0; /* uniqueid match failed */
                }
        } else {
                ret = 0;
        }

        ast_channel_unlock(chan);

        return ret;
}

static struct ast_channel *ast_channel_get_full(const char *name, size_t name_len,
                                                const char *exten, const char *context)
{
        struct ast_channel tmp_chan = {
                .name = name,
                /* This is sort of a hack.  Basically, we're using an arbitrary field
                 * in ast_channel to pass the name_len for a prefix match.  If this
                 * gets changed, then the compare callback must be changed, too. */
                .rings = name_len,
        };
        struct ast_channel *chan;

        if (exten) {
                ast_copy_string(tmp_chan.exten, exten, sizeof(tmp_chan.exten));
        }

        if (context) {
                ast_copy_string(tmp_chan.context, context, sizeof(tmp_chan.context));
        }

        if ((chan = ao2_find(channels, &tmp_chan,
                             (!ast_strlen_zero(name) && (name_len == 0)) ? OBJ_POINTER : 0))) {
                return chan;
        }

        if (!name) {
                return NULL;
        }

        /* If name was specified, but the result was NULL, 
         * try a search on uniqueid, instead. */

        {
                struct ast_channel tmp_chan2 = {
                        .uniqueid = name,
                        .rings = name_len,
                };

                return ao2_find(channels, &tmp_chan2, 0);
        }
}

struct ast_channel *ast_channel_get_by_name(const char *name)
{
        return ast_channel_get_full(name, 0, NULL, NULL);
}

struct ast_channel *ast_channel_get_by_name_prefix(const char *name, size_t name_len)
{
        return ast_channel_get_full(name, name_len, NULL, NULL);
}

struct ast_channel *ast_channel_get_by_exten(const char *exten, const char *context)
{
        return ast_channel_get_full(NULL, 0, exten, context);
}

/*! \brief Wait, look for hangups and condition arg */
int ast_safe_sleep_conditional(struct ast_channel *chan, int ms, int (*cond)(void*), void *data)
{
        struct ast_frame *f;

        while (ms > 0) {
                if (cond && ((*cond)(data) == 0))
                        return 0;
                ms = ast_waitfor(chan, ms);
                if (ms < 0)
                        return -1;
                if (ms > 0) {
                        f = ast_read(chan);
                        if (!f)
                                return -1;
                        ast_frfree(f);
                }
        }
        return 0;
}

/*! \brief Wait, look for hangups */
int ast_safe_sleep(struct ast_channel *chan, int ms)
{
        return ast_safe_sleep_conditional(chan, ms, NULL, NULL);
}

static void free_cid(struct ast_callerid *cid)
{
        if (cid->cid_dnid)
                ast_free(cid->cid_dnid);
        if (cid->cid_num)
                ast_free(cid->cid_num); 
        if (cid->cid_name)
                ast_free(cid->cid_name);        
        if (cid->cid_ani)
                ast_free(cid->cid_ani);
        if (cid->cid_rdnis)
                ast_free(cid->cid_rdnis);
        cid->cid_dnid = cid->cid_num = cid->cid_name = cid->cid_ani = cid->cid_rdnis = NULL;
        ast_party_subaddress_free(&cid->subaddress);
        ast_party_subaddress_free(&cid->dialed_subaddress);
}

struct ast_channel *ast_channel_release(struct ast_channel *chan)
{
        /* Safe, even if already unlinked. */
        ao2_unlink(channels, chan);
        return ast_channel_unref(chan);
}

void ast_party_subaddress_init(struct ast_party_subaddress *init)
{
        init->str = NULL;
        init->type = 0;
        init->odd_even_indicator = 0;
        init->valid = 0;
}

void ast_party_subaddress_copy(struct ast_party_subaddress *dest, const struct ast_party_subaddress *src)
{
        if (dest == src) {
                /* Don't copy to self */
                return;
        }

        if (dest->str) {
                ast_free(dest->str);
        }
        dest->str = ast_strdup(src->str);
        dest->type = src->type;
        dest->odd_even_indicator = src->odd_even_indicator;
        dest->valid = src->valid;
}

void ast_party_subaddress_set_init(struct ast_party_subaddress *init, const struct ast_party_subaddress *guide)
{
        init->str = NULL;
        init->type = guide->type;
        init->odd_even_indicator = guide->odd_even_indicator;
        init->valid = guide->valid;
}

void ast_party_subaddress_set(struct ast_party_subaddress *dest, const struct ast_party_subaddress *src)
{
        if (dest == src) {
                /* Don't set to self */
                return;
        }

        if (src->str && src->str != dest->str) {
                if (dest->str) {
                        ast_free(dest->str);
                }
                dest->str = ast_strdup(src->str);
        }

        dest->type = src->type;
        dest->odd_even_indicator = src->odd_even_indicator;
        dest->valid = src->valid;
}

void ast_party_subaddress_free(struct ast_party_subaddress *doomed)
{
        if (doomed->str) {
                ast_free(doomed->str);
                doomed->str = NULL;
        }
}

/*!
 * \internal
 * \brief Initialize the given party id structure.
 *
 * \param init Party id structure to initialize.
 *
 * \return Nothing
 */
static void ast_party_id_init(struct ast_party_id *init)
{
        init->number = NULL;
        init->name = NULL;
        init->number_type = 0;  /* Unknown */
        init->number_presentation = AST_PRES_ALLOWED_USER_NUMBER_NOT_SCREENED;
        ast_party_subaddress_init(&init->subaddress);
}

/*!
 * \internal
 * \brief Copy the source party id information to the destination party id.
 *
 * \param dest Destination party id
 * \param src Source party id
 *
 * \return Nothing
 */
static void ast_party_id_copy(struct ast_party_id *dest, const struct ast_party_id *src)
{
        if (dest == src) {
                /* Don't copy to self */
                return;
        }

        if (dest->number) {
                ast_free(dest->number);
        }
        dest->number = ast_strdup(src->number);

        if (dest->name) {
                ast_free(dest->name);
        }
        dest->name = ast_strdup(src->name);

        dest->number_type = src->number_type;
        dest->number_presentation = src->number_presentation;
        ast_party_subaddress_copy(&dest->subaddress, &src->subaddress);
}

/*!
 * \internal
 * \brief Initialize the given party id structure using the given guide
 * for a set update operation.
 *
 * \details
 * The initialization is needed to allow a set operation to know if a
 * value needs to be updated.  Simple integers need the guide's original
 * value in case the set operation is not trying to set a new value.
 * String values are simply set to NULL pointers if they are not going
 * to be updated.
 *
 * \param init Party id structure to initialize.
 * \param guide Source party id to use as a guide in initializing.
 *
 * \return Nothing
 */
static void ast_party_id_set_init(struct ast_party_id *init, const struct ast_party_id *guide)
{
        init->number = NULL;
        init->name = NULL;
        init->number_type = guide->number_type;
        init->number_presentation = guide->number_presentation;
        ast_party_subaddress_set_init(&init->subaddress, &guide->subaddress);
}

/*!
 * \internal
 * \brief Set the source party id information into the destination party id.
 *
 * \param dest Destination party id
 * \param src Source party id
 *
 * \return Nothing
 */
static void ast_party_id_set(struct ast_party_id *dest, const struct ast_party_id *src)
{
        if (dest == src) {
                /* Don't set to self */
                return;
        }

        if (src->name && src->name != dest->name) {
                if (dest->name) {
                        ast_free(dest->name);
                }
                dest->name = ast_strdup(src->name);
        }

        if (src->number && src->number != dest->number) {
                if (dest->number) {
                        ast_free(dest->number);
                }
                dest->number = ast_strdup(src->number);
        }

        dest->number_type = src->number_type;
        dest->number_presentation = src->number_presentation;
        ast_party_subaddress_set(&dest->subaddress, &src->subaddress);
}

/*!
 * \internal
 * \brief Destroy the party id contents
 *
 * \param doomed The party id to destroy.
 *
 * \return Nothing
 */
static void ast_party_id_free(struct ast_party_id *doomed)
{
        if (doomed->number) {
                ast_free(doomed->number);
                doomed->number = NULL;
        }

        if (doomed->name) {
                ast_free(doomed->name);
                doomed->name = NULL;
        }
        ast_party_subaddress_free(&doomed->subaddress);
}

void ast_party_caller_init(struct ast_party_caller *init)
{
        ast_party_id_init(&init->id);
        init->ani = NULL;
        init->ani2 = 0;
}

void ast_party_caller_copy(struct ast_callerid *dest, const struct ast_callerid *src)
{
        if (dest == src) {
                /* Don't copy to self */
                return;
        }

#if 1
        /* Copy caller-id specific information ONLY from struct ast_callerid */
        if (dest->cid_num)
        {
                ast_free(dest->cid_num);
        }
        dest->cid_num = ast_strdup(src->cid_num);

        if (dest->cid_name)
        {
                ast_free(dest->cid_name);
        }
        dest->cid_name = ast_strdup(src->cid_name);

        dest->cid_ton = src->cid_ton;
        dest->cid_pres = src->cid_pres;


        if (dest->cid_ani)
        {
                ast_free(dest->cid_ani);
        }
        dest->cid_ani = ast_strdup(src->cid_ani);

        dest->cid_ani2 = src->cid_ani2;

        ast_party_subaddress_copy(&dest->subaddress, &src->subaddress);

#else

        /* The src and dest parameter types will become struct ast_party_caller ptrs. */
        /* This is future code */

        ast_party_id_copy(&dest->id, &src->id);

        if (dest->ani) {
                ast_free(dest->ani);
        }
        dest->ani = ast_strdup(src->ani);

        dest->ani2 = src->ani2;
#endif
}

void ast_party_connected_line_init(struct ast_party_connected_line *init)
{
        ast_party_id_init(&init->id);
        init->ani = NULL;
        init->ani2 = 0;
        init->source = AST_CONNECTED_LINE_UPDATE_SOURCE_UNKNOWN;
}

void ast_party_connected_line_copy(struct ast_party_connected_line *dest, const struct ast_party_connected_line *src)
{
        if (dest == src) {
                /* Don't copy to self */
                return;
        }

        ast_party_id_copy(&dest->id, &src->id);

        if (dest->ani) {
                ast_free(dest->ani);
        }
        dest->ani = ast_strdup(src->ani);

        dest->ani2 = src->ani2;
        dest->source = src->source;
}

void ast_party_connected_line_set_init(struct ast_party_connected_line *init, const struct ast_party_connected_line *guide)
{
        ast_party_id_set_init(&init->id, &guide->id);
        init->ani = NULL;
        init->ani2 = guide->ani2;
        init->source = guide->source;
}

void ast_party_connected_line_set(struct ast_party_connected_line *dest, const struct ast_party_connected_line *src)
{
        ast_party_id_set(&dest->id, &src->id);

        if (src->ani && src->ani != dest->ani) {
                if (dest->ani) {
                        ast_free(dest->ani);
                }
                dest->ani = ast_strdup(src->ani);
        }

        dest->ani2 = src->ani2;
        dest->source = src->source;
}

void ast_party_connected_line_collect_caller(struct ast_party_connected_line *connected, struct ast_callerid *cid)
{
        connected->id.number = cid->cid_num;
        connected->id.name = cid->cid_name;
        connected->id.number_type = cid->cid_ton;
        connected->id.number_presentation = cid->cid_pres;
        connected->id.subaddress = cid->subaddress;

        connected->ani = cid->cid_ani;
        connected->ani2 = cid->cid_ani2;
        connected->source = AST_CONNECTED_LINE_UPDATE_SOURCE_UNKNOWN;
}

void ast_party_connected_line_free(struct ast_party_connected_line *doomed)
{
        ast_party_id_free(&doomed->id);

        if (doomed->ani) {
                ast_free(doomed->ani);
                doomed->ani = NULL;
        }
}

void ast_party_redirecting_copy(struct ast_party_redirecting *dest, const struct ast_party_redirecting *src)
{
        if (dest == src) {
                /* Don't copy to self */
                return;
        }

        ast_party_id_copy(&dest->from, &src->from);
        ast_party_id_copy(&dest->to, &src->to);
        dest->count = src->count;
        dest->reason = src->reason;
}

void ast_party_redirecting_set_init(struct ast_party_redirecting *init, const struct ast_party_redirecting *guide)
{
        ast_party_id_set_init(&init->from, &guide->from);
        ast_party_id_set_init(&init->to, &guide->to);
        init->count = guide->count;
        init->reason = guide->reason;
}

void ast_party_redirecting_free(struct ast_party_redirecting *doomed)
{
        ast_party_id_free(&doomed->from);
        ast_party_id_free(&doomed->to);
}

/*! \brief Free a channel structure */
static void ast_channel_destructor(void *obj)
{
        struct ast_channel *chan = obj;
        int fd;
#ifdef HAVE_EPOLL
        int i;
#endif
        struct ast_var_t *vardata;
        struct ast_frame *f;
        struct varshead *headp;
        struct ast_datastore *datastore = NULL;
        char name[AST_CHANNEL_NAME], *dashptr;

        headp = &chan->varshead;

        ast_cel_report_event(chan, AST_CEL_CHANNEL_END, NULL, NULL, NULL);
        ast_cel_check_retire_linkedid(chan);

        /* Get rid of each of the data stores on the channel */
        while ((datastore = AST_LIST_REMOVE_HEAD(&chan->datastores, entry)))
                /* Free the data store */
                ast_datastore_free(datastore);

        /* Lock and unlock the channel just to be sure nobody has it locked still
           due to a reference that was stored in a datastore. (i.e. app_chanspy) */
        ast_channel_lock(chan);
        ast_channel_unlock(chan);

        if (chan->tech_pvt) {
                ast_log(LOG_WARNING, "Channel '%s' may not have been hung up properly\n", chan->name);
                ast_free(chan->tech_pvt);
        }

        if (chan->sched)
                sched_context_destroy(chan->sched);

        ast_copy_string(name, chan->name, sizeof(name));
        if ((dashptr = strrchr(name, '-'))) {
                *dashptr = '\0';
        }

        /* Stop monitoring */
        if (chan->monitor)
                chan->monitor->stop( chan, 0 );

        /* If there is native format music-on-hold state, free it */
        if (chan->music_state)
                ast_moh_cleanup(chan);

        /* Free translators */
        if (chan->readtrans)
                ast_translator_free_path(chan->readtrans);
        if (chan->writetrans)
                ast_translator_free_path(chan->writetrans);
        if (chan->pbx)
                ast_log(LOG_WARNING, "PBX may not have been terminated properly on '%s'\n", chan->name);

        free_cid(&chan->cid);
        ast_party_connected_line_free(&chan->connected);
        ast_party_redirecting_free(&chan->redirecting);

        /* Close pipes if appropriate */
        if ((fd = chan->alertpipe[0]) > -1)
                close(fd);
        if ((fd = chan->alertpipe[1]) > -1)
                close(fd);
        if (chan->timer) {
                ast_timer_close(chan->timer);
        }
#ifdef HAVE_EPOLL
        for (i = 0; i < AST_MAX_FDS; i++) {
                if (chan->epfd_data[i])
                        free(chan->epfd_data[i]);
        }
        close(chan->epfd);
#endif
        while ((f = AST_LIST_REMOVE_HEAD(&chan->readq, frame_list)))
                ast_frfree(f);
        
        /* loop over the variables list, freeing all data and deleting list items */
        /* no need to lock the list, as the channel is already locked */
        
        while ((vardata = AST_LIST_REMOVE_HEAD(headp, entries)))
                ast_var_delete(vardata);

        ast_app_group_discard(chan);

        /* Destroy the jitterbuffer */
        ast_jb_destroy(chan);

        if (chan->cdr) {
                ast_cdr_discard(chan->cdr);
                chan->cdr = NULL;
        }

        if (chan->zone) {
                chan->zone = ast_tone_zone_unref(chan->zone);
        }

        ast_string_field_free_memory(chan);

        /* Queue an unknown state, because, while we know that this particular
         * instance is dead, we don't know the state of all other possible
         * instances. */
        ast_devstate_changed_literal(AST_DEVICE_UNKNOWN, name);
}

/*! \brief Free a dummy channel structure */
static void ast_dummy_channel_destructor(void *obj)
{
        struct ast_channel *chan = obj;
        struct ast_var_t *vardata;
        struct varshead *headp;

        headp = &chan->varshead;

        free_cid(&chan->cid);

        /* loop over the variables list, freeing all data and deleting list items */
        /* no need to lock the list, as the channel is already locked */
        while ((vardata = AST_LIST_REMOVE_HEAD(headp, entries)))
                ast_var_delete(vardata);

        if (chan->cdr) {
                ast_cdr_discard(chan->cdr);
                chan->cdr = NULL;
        }

        ast_string_field_free_memory(chan);
}

struct ast_datastore *ast_channel_datastore_alloc(const struct ast_datastore_info *info, const char *uid)
{
        return ast_datastore_alloc(info, uid);
}

int ast_channel_datastore_free(struct ast_datastore *datastore)
{
        return ast_datastore_free(datastore);
}

int ast_channel_datastore_inherit(struct ast_channel *from, struct ast_channel *to)
{
        struct ast_datastore *datastore = NULL, *datastore2;

        AST_LIST_TRAVERSE(&from->datastores, datastore, entry) {
                if (datastore->inheritance > 0) {
                        datastore2 = ast_datastore_alloc(datastore->info, datastore->uid);
                        if (datastore2) {
                                datastore2->data = datastore->info->duplicate ? datastore->info->duplicate(datastore->data) : NULL;
                                datastore2->inheritance = datastore->inheritance == DATASTORE_INHERIT_FOREVER ? DATASTORE_INHERIT_FOREVER : datastore->inheritance - 1;
                                AST_LIST_INSERT_TAIL(&to->datastores, datastore2, entry);
                        }
                }
        }
        return 0;
}

int ast_channel_datastore_add(struct ast_channel *chan, struct ast_datastore *datastore)
{
        int res = 0;

        AST_LIST_INSERT_HEAD(&chan->datastores, datastore, entry);

        return res;
}

int ast_channel_datastore_remove(struct ast_channel *chan, struct ast_datastore *datastore)
{
        return AST_LIST_REMOVE(&chan->datastores, datastore, entry) ? 0 : -1;
}

struct ast_datastore *ast_channel_datastore_find(struct ast_channel *chan, const struct ast_datastore_info *info, const char *uid)
{
        struct ast_datastore *datastore = NULL;
        
        if (info == NULL)
                return NULL;

        AST_LIST_TRAVERSE_SAFE_BEGIN(&chan->datastores, datastore, entry) {
                if (datastore->info != info) {
                        continue;
                }

                if (uid == NULL) {
                        /* matched by type only */
                        break;
                }

                if ((datastore->uid != NULL) && !strcasecmp(uid, datastore->uid)) {
                        /* Matched by type AND uid */
                        break;
                }
        }
        AST_LIST_TRAVERSE_SAFE_END;

        return datastore;
}

/*! Set the file descriptor on the channel */
void ast_channel_set_fd(struct ast_channel *chan, int which, int fd)
{
#ifdef HAVE_EPOLL
        struct epoll_event ev;
        struct ast_epoll_data *aed = NULL;

        if (chan->fds[which] > -1) {
                epoll_ctl(chan->epfd, EPOLL_CTL_DEL, chan->fds[which], &ev);
                aed = chan->epfd_data[which];
        }

        /* If this new fd is valid, add it to the epoll */
        if (fd > -1) {
                if (!aed && (!(aed = ast_calloc(1, sizeof(*aed)))))
                        return;
                
                chan->epfd_data[which] = aed;
                aed->chan = chan;
                aed->which = which;
                
                ev.events = EPOLLIN | EPOLLPRI | EPOLLERR | EPOLLHUP;
                ev.data.ptr = aed;
                epoll_ctl(chan->epfd, EPOLL_CTL_ADD, fd, &ev);
        } else if (aed) {
                /* We don't have to keep around this epoll data structure now */
                free(aed);
                chan->epfd_data[which] = NULL;
        }
#endif
        chan->fds[which] = fd;
        return;
}

/*! Add a channel to an optimized waitfor */
void ast_poll_channel_add(struct ast_channel *chan0, struct ast_channel *chan1)
{
#ifdef HAVE_EPOLL
        struct epoll_event ev;
        int i = 0;

        if (chan0->epfd == -1)
                return;

        /* Iterate through the file descriptors on chan1, adding them to chan0 */
        for (i = 0; i < AST_MAX_FDS; i++) {
                if (chan1->fds[i] == -1)
                        continue;
                ev.events = EPOLLIN | EPOLLPRI | EPOLLERR | EPOLLHUP;
                ev.data.ptr = chan1->epfd_data[i];
                epoll_ctl(chan0->epfd, EPOLL_CTL_ADD, chan1->fds[i], &ev);
        }

#endif
        return;
}

/*! Delete a channel from an optimized waitfor */
void ast_poll_channel_del(struct ast_channel *chan0, struct ast_channel *chan1)
{
#ifdef HAVE_EPOLL
        struct epoll_event ev;
        int i = 0;

        if (chan0->epfd == -1)
                return;

        for (i = 0; i < AST_MAX_FDS; i++) {
                if (chan1->fds[i] == -1)
                        continue;
                epoll_ctl(chan0->epfd, EPOLL_CTL_DEL, chan1->fds[i], &ev);
        }

#endif
        return;
}

/*! \brief Softly hangup a channel, don't lock */
int ast_softhangup_nolock(struct ast_channel *chan, int cause)
{
        ast_debug(1, "Soft-Hanging up channel '%s'\n", chan->name);
        /* Inform channel driver that we need to be hung up, if it cares */
        chan->_softhangup |= cause;
        ast_queue_frame(chan, &ast_null_frame);
        /* Interrupt any poll call or such */
        if (ast_test_flag(chan, AST_FLAG_BLOCKING))
                pthread_kill(chan->blocker, SIGURG);
        return 0;
}

/*! \brief Softly hangup a channel, lock */
int ast_softhangup(struct ast_channel *chan, int cause)
{
        int res;

        ast_channel_lock(chan);
        res = ast_softhangup_nolock(chan, cause);
        ast_channel_unlock(chan);

        return res;
}

static void free_translation(struct ast_channel *clonechan)
{
        if (clonechan->writetrans)
                ast_translator_free_path(clonechan->writetrans);
        if (clonechan->readtrans)
                ast_translator_free_path(clonechan->readtrans);
        clonechan->writetrans = NULL;
        clonechan->readtrans = NULL;
        clonechan->rawwriteformat = clonechan->nativeformats;
        clonechan->rawreadformat = clonechan->nativeformats;
}

void ast_set_hangupsource(struct ast_channel *chan, const char *source, int force)
{
        struct ast_channel *bridge;

        ast_channel_lock(chan);
        if (force || ast_strlen_zero(chan->hangupsource)) {
                ast_string_field_set(chan, hangupsource, source);
        }
        bridge = ast_bridged_channel(chan);
        ast_channel_unlock(chan);

        if (bridge && (force || ast_strlen_zero(bridge->hangupsource))) {
                ast_channel_lock(bridge);
                ast_string_field_set(chan, hangupsource, source);
                ast_channel_unlock(bridge);
        }
}

/*! \brief Hangup a channel */
int ast_hangup(struct ast_channel *chan)
{
        int res = 0;
        char extra_str[64]; /* used for cel logging below */

        /* Don't actually hang up a channel that will masquerade as someone else, or
           if someone is going to masquerade as us */
        ast_channel_lock(chan);

        if (chan->audiohooks) {
                ast_audiohook_detach_list(chan->audiohooks);
                chan->audiohooks = NULL;
        }

        ast_autoservice_stop(chan);

        if (chan->masq) {
                ast_channel_unlock(chan);
                if (ast_do_masquerade(chan)) {
                        ast_log(LOG_WARNING, "Failed to perform masquerade\n");
                }
                ast_channel_lock(chan);
        }

        if (chan->masq) {
                ast_log(LOG_WARNING, "%s getting hung up, but someone is trying to masq into us?!?\n", chan->name);
                ast_channel_unlock(chan);
                return 0;
        }
        /* If this channel is one which will be masqueraded into something,
           mark it as a zombie already, so we know to free it later */
        if (chan->masqr) {
                ast_set_flag(chan, AST_FLAG_ZOMBIE);
                ast_channel_unlock(chan);
                return 0;
        }
        ast_channel_unlock(chan);

        ao2_unlink(channels, chan);

        ast_channel_lock(chan);
        free_translation(chan);
        /* Close audio stream */
        if (chan->stream) {
                ast_closestream(chan->stream);
                chan->stream = NULL;
        }
        /* Close video stream */
        if (chan->vstream) {
                ast_closestream(chan->vstream);
                chan->vstream = NULL;
        }
        if (chan->sched) {
                sched_context_destroy(chan->sched);
                chan->sched = NULL;
        }

        if (chan->generatordata)        /* Clear any tone stuff remaining */
                if (chan->generator && chan->generator->release)
                        chan->generator->release(chan, chan->generatordata);
        chan->generatordata = NULL;
        chan->generator = NULL;

        snprintf(extra_str, sizeof(extra_str), "%d,%s,%s", chan->hangupcause, chan->hangupsource, S_OR(pbx_builtin_getvar_helper(chan, "DIALSTATUS"), ""));
        ast_cel_report_event(chan, AST_CEL_HANGUP, NULL, extra_str, NULL);

        if (ast_test_flag(chan, AST_FLAG_BLOCKING)) {
                ast_log(LOG_WARNING, "Hard hangup called by thread %ld on %s, while fd "
                                        "is blocked by thread %ld in procedure %s!  Expect a failure\n",
                                        (long)pthread_self(), chan->name, (long)chan->blocker, chan->blockproc);
                ast_assert(ast_test_flag(chan, AST_FLAG_BLOCKING) == 0);
        }
        if (!ast_test_flag(chan, AST_FLAG_ZOMBIE)) {
                ast_debug(1, "Hanging up channel '%s'\n", chan->name);
                if (chan->tech->hangup)
                        res = chan->tech->hangup(chan);
        } else {
                ast_debug(1, "Hanging up zombie '%s'\n", chan->name);
        }
                        
        ast_channel_unlock(chan);
        ast_manager_event(chan, EVENT_FLAG_CALL, "Hangup",
                        "Channel: %s\r\n"
                        "Uniqueid: %s\r\n"
                        "CallerIDNum: %s\r\n"
                        "CallerIDName: %s\r\n"
                        "Cause: %d\r\n"
                        "Cause-txt: %s\r\n",
                        chan->name,
                        chan->uniqueid,
                        S_OR(chan->cid.cid_num, "<unknown>"),
                        S_OR(chan->cid.cid_name, "<unknown>"),
                        chan->hangupcause,
                        ast_cause2str(chan->hangupcause)
                        );

        if (chan->cdr && !ast_test_flag(chan->cdr, AST_CDR_FLAG_BRIDGED) && 
                !ast_test_flag(chan->cdr, AST_CDR_FLAG_POST_DISABLED) && 
            (chan->cdr->disposition != AST_CDR_NULL || ast_test_flag(chan->cdr, AST_CDR_FLAG_DIALED))) {
                ast_channel_lock(chan);
                        
                ast_cdr_end(chan->cdr);
                ast_cdr_detach(chan->cdr);
                chan->cdr = NULL;
                ast_channel_unlock(chan);
        }

        chan = ast_channel_release(chan);

        return res;
}

int ast_raw_answer(struct ast_channel *chan, int cdr_answer)
{
        int res = 0;

        ast_channel_lock(chan);

        /* You can't answer an outbound call */
        if (ast_test_flag(chan, AST_FLAG_OUTGOING)) {
                ast_channel_unlock(chan);
                return 0;
        }

        /* Stop if we're a zombie or need a soft hangup */
        if (ast_test_flag(chan, AST_FLAG_ZOMBIE) || ast_check_hangup(chan)) {
                ast_channel_unlock(chan);
                return -1;
        }

        ast_channel_unlock(chan);

        switch (chan->_state) {
        case AST_STATE_RINGING:
        case AST_STATE_RING:
                ast_channel_lock(chan);
                if (chan->tech->answer) {
                        res = chan->tech->answer(chan);
                }
                ast_setstate(chan, AST_STATE_UP);
                if (cdr_answer) {
                        ast_cdr_answer(chan->cdr);
                }
                ast_cel_report_event(chan, AST_CEL_ANSWER, NULL, NULL, NULL);
                ast_channel_unlock(chan);
                break;
        case AST_STATE_UP:
                ast_cel_report_event(chan, AST_CEL_ANSWER, NULL, NULL, NULL);
                /* Calling ast_cdr_answer when it it has previously been called
                 * is essentially a no-op, so it is safe.
                 */
                if (cdr_answer) {
                        ast_cdr_answer(chan->cdr);
                }
                break;
        default:
                break;
        }

        ast_indicate(chan, -1);
        chan->visible_indication = 0;

        return res;
}

int __ast_answer(struct ast_channel *chan, unsigned int delay, int cdr_answer)
{
        int res = 0;
        enum ast_channel_state old_state;

        old_state = chan->_state;
        if ((res = ast_raw_answer(chan, cdr_answer))) {
                return res;
        }

        switch (old_state) {
        case AST_STATE_RINGING:
        case AST_STATE_RING:
                /* wait for media to start flowing, but don't wait any longer
                 * than 'delay' or 500 milliseconds, whichever is longer
                 */
                do {
                        AST_LIST_HEAD_NOLOCK(, ast_frame) frames;
                        struct ast_frame *cur, *new;
                        int ms = MAX(delay, 500);
                        unsigned int done = 0;

                        AST_LIST_HEAD_INIT_NOLOCK(&frames);

                        for (;;) {
                                ms = ast_waitfor(chan, ms);
                                if (ms < 0) {
                                        ast_log(LOG_WARNING, "Error condition occurred when polling channel %s for a voice frame: %s\n", chan->name, strerror(errno));
                                        res = -1;
                                        break;
                                }
                                if (ms == 0) {
                                        ast_debug(2, "Didn't receive a media frame from %s within %d ms of answering. Continuing anyway\n", chan->name, MAX(delay, 500));
                                        break;
                                }
                                cur = ast_read(chan);
                                if (!cur || ((cur->frametype == AST_FRAME_CONTROL) &&
                                             (cur->subclass.integer == AST_CONTROL_HANGUP))) {
                                        if (cur) {
                                                ast_frfree(cur);
                                        }
                                        res = -1;
                                        ast_debug(2, "Hangup of channel %s detected in answer routine\n", chan->name);
                                        break;
                                }

                                if ((new = ast_frisolate(cur)) != cur) {
                                        ast_frfree(cur);
                                }

                                AST_LIST_INSERT_HEAD(&frames, new, frame_list);

                                /* if a specific delay period was requested, continue
                                 * until that delay has passed. don't stop just because
                                 * incoming media has arrived.
                                 */
                                if (delay) {
                                        continue;
                                }

                                switch (new->frametype) {
                                        /* all of these frametypes qualify as 'media' */
                                case AST_FRAME_VOICE:
                                case AST_FRAME_VIDEO:
                                case AST_FRAME_TEXT:
                                case AST_FRAME_DTMF_BEGIN:
                                case AST_FRAME_DTMF_END:
                                case AST_FRAME_IMAGE:
                                case AST_FRAME_HTML:
                                case AST_FRAME_MODEM:
                                        done = 1;
                                        break;
                                case AST_FRAME_CONTROL:
                                case AST_FRAME_IAX:
                                case AST_FRAME_NULL:
                                case AST_FRAME_CNG:
                                        break;
                                }

                                if (done) {
                                        break;
                                }
                        }

                        if (res == 0) {
                                ast_channel_lock(chan);
                                while ((cur = AST_LIST_REMOVE_HEAD(&frames, frame_list))) {
                                        ast_queue_frame_head(chan, cur);
                                        ast_frfree(cur);
                                }
                                ast_channel_unlock(chan);
                        }
                } while (0);
                break;
        default:
                break;
        }

        return res;
}

int ast_answer(struct ast_channel *chan)
{
        return __ast_answer(chan, 0, 1);
}

void ast_deactivate_generator(struct ast_channel *chan)
{
        ast_channel_lock(chan);
        if (chan->generatordata) {
                if (chan->generator && chan->generator->release)
                        chan->generator->release(chan, chan->generatordata);
                chan->generatordata = NULL;
                chan->generator = NULL;
                ast_channel_set_fd(chan, AST_GENERATOR_FD, -1);
                ast_clear_flag(chan, AST_FLAG_WRITE_INT);
                ast_settimeout(chan, 0, NULL, NULL);
        }
        ast_channel_unlock(chan);
}

static int generator_force(const void *data)
{
        /* Called if generator doesn't have data */
        void *tmp;
        int res;
        int (*generate)(struct ast_channel *chan, void *tmp, int datalen, int samples) = NULL;
        struct ast_channel *chan = (struct ast_channel *)data;

        ast_channel_lock(chan);
        tmp = chan->generatordata;
        chan->generatordata = NULL;
        if (chan->generator)
                generate = chan->generator->generate;
        ast_channel_unlock(chan);

        if (!tmp || !generate)
                return 0;

        res = generate(chan, tmp, 0, ast_format_rate(chan->writeformat & AST_FORMAT_AUDIO_MASK) / 50);

        chan->generatordata = tmp;

        if (res) {
                ast_debug(1, "Auto-deactivating generator\n");
                ast_deactivate_generator(chan);
        }

        return 0;
}

int ast_activate_generator(struct ast_channel *chan, struct ast_generator *gen, void *params)
{
        int res = 0;

        ast_channel_lock(chan);

        if (chan->generatordata) {
                if (chan->generator && chan->generator->release)
                        chan->generator->release(chan, chan->generatordata);
                chan->generatordata = NULL;
        }

        ast_prod(chan);
        if (gen->alloc && !(chan->generatordata = gen->alloc(chan, params))) {
                res = -1;
        }
        
        if (!res) {
                ast_settimeout(chan, 50, generator_force, chan);
                chan->generator = gen;
        }

        ast_channel_unlock(chan);

        return res;
}

/*! \brief Wait for x amount of time on a file descriptor to have input.  */
int ast_waitfor_n_fd(int *fds, int n, int *ms, int *exception)
{
        int winner = -1;
        ast_waitfor_nandfds(NULL, 0, fds, n, exception, &winner, ms);
        return winner;
}

/*! \brief Wait for x amount of time on a file descriptor to have input.  */
#ifdef HAVE_EPOLL
static struct ast_channel *ast_waitfor_nandfds_classic(struct ast_channel **c, int n, int *fds, int nfds,
                                        int *exception, int *outfd, int *ms)
#else
struct ast_channel *ast_waitfor_nandfds(struct ast_channel **c, int n, int *fds, int nfds,
                                        int *exception, int *outfd, int *ms)
#endif
{
        struct timeval start = { 0 , 0 };
        struct pollfd *pfds = NULL;
        int res;
        long rms;
        int x, y, max;
        int sz;
        struct timeval now = { 0, 0 };
        struct timeval whentohangup = { 0, 0 }, diff;
        struct ast_channel *winner = NULL;
        struct fdmap {
                int chan;
                int fdno;
        } *fdmap = NULL;

        if ((sz = n * AST_MAX_FDS + nfds)) {
                pfds = alloca(sizeof(*pfds) * sz);
                fdmap = alloca(sizeof(*fdmap) * sz);
        }

        if (outfd)
                *outfd = -99999;
        if (exception)
                *exception = 0;
        
        /* Perform any pending masquerades */
        for (x = 0; x < n; x++) {
                if (c[x]->masq && ast_do_masquerade(c[x])) {
                        ast_log(LOG_WARNING, "Masquerade failed\n");
                        *ms = -1;
                        return NULL;
                }

                ast_channel_lock(c[x]);
                if (!ast_tvzero(c[x]->whentohangup)) {
                        if (ast_tvzero(whentohangup))
                                now = ast_tvnow();
                        diff = ast_tvsub(c[x]->whentohangup, now);
                        if (diff.tv_sec < 0 || ast_tvzero(diff)) {
                                /* Should already be hungup */
                                c[x]->_softhangup |= AST_SOFTHANGUP_TIMEOUT;
                                ast_channel_unlock(c[x]);
                                return c[x];
                        }
                        if (ast_tvzero(whentohangup) || ast_tvcmp(diff, whentohangup) < 0)
                                whentohangup = diff;
                }
                ast_channel_unlock(c[x]);
        }
        /* Wait full interval */
        rms = *ms;
        if (!ast_tvzero(whentohangup)) {
                rms = whentohangup.tv_sec * 1000 + whentohangup.tv_usec / 1000;              /* timeout in milliseconds */
                if (*ms >= 0 && *ms < rms)              /* original *ms still smaller */
                        rms =  *ms;
        }
        /*
         * Build the pollfd array, putting the channels' fds first,
         * followed by individual fds. Order is important because
         * individual fd's must have priority over channel fds.
         */
        max = 0;
        for (x = 0; x < n; x++) {
                for (y = 0; y < AST_MAX_FDS; y++) {
                        fdmap[max].fdno = y;  /* fd y is linked to this pfds */
                        fdmap[max].chan = x;  /* channel x is linked to this pfds */
                        max += ast_add_fd(&pfds[max], c[x]->fds[y]);
                }
                CHECK_BLOCKING(c[x]);
        }
        /* Add the individual fds */
        for (x = 0; x < nfds; x++) {
                fdmap[max].chan = -1;
                max += ast_add_fd(&pfds[max], fds[x]);
        }

        if (*ms > 0)
                start = ast_tvnow();
        
        if (sizeof(int) == 4) { /* XXX fix timeout > 600000 on linux x86-32 */
                do {
                        int kbrms = rms;
                        if (kbrms > 600000)
                                kbrms = 600000;
                        res = ast_poll(pfds, max, kbrms);
                        if (!res)
                                rms -= kbrms;
                } while (!res && (rms > 0));
        } else {
                res = ast_poll(pfds, max, rms);
        }
        for (x = 0; x < n; x++)
                ast_clear_flag(c[x], AST_FLAG_BLOCKING);
        if (res < 0) { /* Simulate a timeout if we were interrupted */
                if (errno != EINTR)
                        *ms = -1;
                return NULL;
        }
        if (!ast_tvzero(whentohangup)) {   /* if we have a timeout, check who expired */
                now = ast_tvnow();
                for (x = 0; x < n; x++) {
                        if (!ast_tvzero(c[x]->whentohangup) && ast_tvcmp(c[x]->whentohangup, now) <= 0) {
                                c[x]->_softhangup |= AST_SOFTHANGUP_TIMEOUT;
                                if (winner == NULL)
                                        winner = c[x];
                        }
                }
        }
        if (res == 0) { /* no fd ready, reset timeout and done */
                *ms = 0;        /* XXX use 0 since we may not have an exact timeout. */
                return winner;
        }
        /*
         * Then check if any channel or fd has a pending event.
         * Remember to check channels first and fds last, as they
         * must have priority on setting 'winner'
         */
        for (x = 0; x < max; x++) {
                res = pfds[x].revents;
                if (res == 0)
                        continue;
                if (fdmap[x].chan >= 0) {       /* this is a channel */
                        winner = c[fdmap[x].chan];      /* override previous winners */
                        if (res & POLLPRI)
                                ast_set_flag(winner, AST_FLAG_EXCEPTION);
                        else
                                ast_clear_flag(winner, AST_FLAG_EXCEPTION);
                        winner->fdno = fdmap[x].fdno;
                } else {                        /* this is an fd */
                        if (outfd)
                                *outfd = pfds[x].fd;
                        if (exception)
                                *exception = (res & POLLPRI) ? -1 : 0;
                        winner = NULL;
                }
        }
        if (*ms > 0) {
                *ms -= ast_tvdiff_ms(ast_tvnow(), start);
                if (*ms < 0)
                        *ms = 0;
        }
        return winner;
}

#ifdef HAVE_EPOLL
static struct ast_channel *ast_waitfor_nandfds_simple(struct ast_channel *chan, int *ms)
{
        struct timeval start = { 0 , 0 };
        int res = 0;
        struct epoll_event ev[1];
        long diff, rms = *ms;
        struct ast_channel *winner = NULL;
        struct ast_epoll_data *aed = NULL;


        /* See if this channel needs to be masqueraded */
        if (chan->masq && ast_do_masquerade(chan)) {
                ast_log(LOG_WARNING, "Failed to perform masquerade on %s\n", chan->name);
                *ms = -1;
                return NULL;
        }

        ast_channel_lock(chan);
        /* Figure out their timeout */
        if (!ast_tvzero(chan->whentohangup)) {
                if ((diff = ast_tvdiff_ms(chan->whentohangup, ast_tvnow())) < 0) {
                        /* They should already be hungup! */
                        chan->_softhangup |= AST_SOFTHANGUP_TIMEOUT;
                        ast_channel_unlock(chan);
                        return NULL;
                }
                /* If this value is smaller then the current one... make it priority */
                if (rms > diff)
                        rms = diff;
        }

        ast_channel_unlock(chan);

        /* Time to make this channel block... */
        CHECK_BLOCKING(chan);

        if (*ms > 0)
                start = ast_tvnow();

        /* We don't have to add any file descriptors... they are already added, we just have to wait! */
        res = epoll_wait(chan->epfd, ev, 1, rms);

        /* Stop blocking */
        ast_clear_flag(chan, AST_FLAG_BLOCKING);

        /* Simulate a timeout if we were interrupted */
        if (res < 0) {
                if (errno != EINTR)
                        *ms = -1;
                return NULL;
        }

        /* If this channel has a timeout see if it expired */
        if (!ast_tvzero(chan->whentohangup)) {
                if (ast_tvdiff_ms(ast_tvnow(), chan->whentohangup) >= 0) {
                        chan->_softhangup |= AST_SOFTHANGUP_TIMEOUT;
                        winner = chan;
                }
        }

        /* No fd ready, reset timeout and be done for now */
        if (!res) {
                *ms = 0;
                return winner;
        }

        /* See what events are pending */
        aed = ev[0].data.ptr;
        chan->fdno = aed->which;
        if (ev[0].events & EPOLLPRI)
                ast_set_flag(chan, AST_FLAG_EXCEPTION);
        else
                ast_clear_flag(chan, AST_FLAG_EXCEPTION);

        if (*ms > 0) {
                *ms -= ast_tvdiff_ms(ast_tvnow(), start);
                if (*ms < 0)
                        *ms = 0;
        }

        return chan;
}

static struct ast_channel *ast_waitfor_nandfds_complex(struct ast_channel **c, int n, int *ms)
{
        struct timeval start = { 0 , 0 };
        int res = 0, i;
        struct epoll_event ev[25] = { { 0, } };
        struct timeval now = { 0, 0 };
        long whentohangup = 0, diff = 0, rms = *ms;
        struct ast_channel *winner = NULL;

        for (i = 0; i < n; i++) {
                if (c[i]->masq && ast_do_masquerade(c[i])) {
                        ast_log(LOG_WARNING, "Masquerade failed\n");
                        *ms = -1;
                        return NULL;
                }

                ast_channel_lock(c[i]);
                if (!ast_tvzero(c[i]->whentohangup)) {
                        if (whentohangup == 0)
                                now = ast_tvnow();
                        if ((diff = ast_tvdiff_ms(c[i]->whentohangup, now)) < 0) {
                                c[i]->_softhangup |= AST_SOFTHANGUP_TIMEOUT;
                                ast_channel_unlock(c[i]);
                                return c[i];
                        }
                        if (!whentohangup || whentohangup > diff)
                                whentohangup = diff;
                }
                ast_channel_unlock(c[i]);
                CHECK_BLOCKING(c[i]);
        }

        rms = *ms;
        if (whentohangup) {
                rms = whentohangup;
                if (*ms >= 0 && *ms < rms)
                        rms = *ms;
        }

        if (*ms > 0)
                start = ast_tvnow();

        res = epoll_wait(c[0]->epfd, ev, 25, rms);

        for (i = 0; i < n; i++)
                ast_clear_flag(c[i], AST_FLAG_BLOCKING);

        if (res < 0) {
                if (errno != EINTR)
                        *ms = -1;
                return NULL;
        }

        if (whentohangup) {
                now = ast_tvnow();
                for (i = 0; i < n; i++) {
                        if (!ast_tvzero(c[i]->whentohangup) && ast_tvdiff_ms(now, c[i]->whentohangup) >= 0) {
                                c[i]->_softhangup |= AST_SOFTHANGUP_TIMEOUT;
                                if (!winner)
                                        winner = c[i];
                        }
                }
        }

        if (!res) {
                *ms = 0;
                return winner;
        }

        for (i = 0; i < res; i++) {
                struct ast_epoll_data *aed = ev[i].data.ptr;

                if (!ev[i].events || !aed)
                        continue;

                winner = aed->chan;
                if (ev[i].events & EPOLLPRI)
                        ast_set_flag(winner, AST_FLAG_EXCEPTION);
                else
                        ast_clear_flag(winner, AST_FLAG_EXCEPTION);
                winner->fdno = aed->which;
        }

        if (*ms > 0) {
                *ms -= ast_tvdiff_ms(ast_tvnow(), start);
                if (*ms < 0)
                        *ms = 0;
        }

        return winner;
}

struct ast_channel *ast_waitfor_nandfds(struct ast_channel **c, int n, int *fds, int nfds,
                                        int *exception, int *outfd, int *ms)
{
        /* Clear all provided values in one place. */
        if (outfd)
                *outfd = -99999;
        if (exception)
                *exception = 0;

        /* If no epoll file descriptor is available resort to classic nandfds */
        if (!n || nfds || c[0]->epfd == -1)
                return ast_waitfor_nandfds_classic(c, n, fds, nfds, exception, outfd, ms);
        else if (!nfds && n == 1)
                return ast_waitfor_nandfds_simple(c[0], ms);
        else
                return ast_waitfor_nandfds_complex(c, n, ms);
}
#endif

struct ast_channel *ast_waitfor_n(struct ast_channel **c, int n, int *ms)
{
        return ast_waitfor_nandfds(c, n, NULL, 0, NULL, NULL, ms);
}

int ast_waitfor(struct ast_channel *c, int ms)
{
        int oldms = ms; /* -1 if no timeout */

        ast_waitfor_nandfds(&c, 1, NULL, 0, NULL, NULL, &ms);
        if ((ms < 0) && (oldms < 0))
                ms = 0;
        return ms;
}

/* XXX never to be called with ms = -1 */
int ast_waitfordigit(struct ast_channel *c, int ms)
{
        return ast_waitfordigit_full(c, ms, -1, -1);
}

int ast_settimeout(struct ast_channel *c, unsigned int rate, int (*func)(const void *data), void *data)
{
        int res;
        unsigned int real_rate = rate, max_rate;

        ast_channel_lock(c);

        if (c->timingfd == -1) {
                ast_channel_unlock(c);
                return -1;
        }

        if (!func) {
                rate = 0;
                data = NULL;
        }

        if (rate && rate > (max_rate = ast_timer_get_max_rate(c->timer))) {
                real_rate = max_rate;
        }

        ast_debug(1, "Scheduling timer at (%u requested / %u actual) timer ticks per second\n", rate, real_rate);

        res = ast_timer_set_rate(c->timer, real_rate);

        c->timingfunc = func;
        c->timingdata = data;

        ast_channel_unlock(c);

        return res;
}

int ast_waitfordigit_full(struct ast_channel *c, int ms, int audiofd, int cmdfd)
{
        /* Stop if we're a zombie or need a soft hangup */
        if (ast_test_flag(c, AST_FLAG_ZOMBIE) || ast_check_hangup(c))
                return -1;

        /* Only look for the end of DTMF, don't bother with the beginning and don't emulate things */
        ast_set_flag(c, AST_FLAG_END_DTMF_ONLY);

        /* Wait for a digit, no more than ms milliseconds total. */
        
        while (ms) {
                struct ast_channel *rchan;
                int outfd=-1;

                errno = 0;
                rchan = ast_waitfor_nandfds(&c, 1, &cmdfd, (cmdfd > -1) ? 1 : 0, NULL, &outfd, &ms);
                
                if (!rchan && outfd < 0 && ms) {
                        if (errno == 0 || errno == EINTR)
                                continue;
                        ast_log(LOG_WARNING, "Wait failed (%s)\n", strerror(errno));
                        ast_clear_flag(c, AST_FLAG_END_DTMF_ONLY);
                        return -1;
                } else if (outfd > -1) {
                        /* The FD we were watching has something waiting */
                        ast_log(LOG_WARNING, "The FD we were waiting for has something waiting. Waitfordigit returning numeric 1\n");
                        ast_clear_flag(c, AST_FLAG_END_DTMF_ONLY);
                        return 1;
                } else if (rchan) {
                        int res;
                        struct ast_frame *f = ast_read(c);
                        if (!f)
                                return -1;

                        switch (f->frametype) {
                        case AST_FRAME_DTMF_BEGIN:
                                break;
                        case AST_FRAME_DTMF_END:
                                res = f->subclass.integer;
                                ast_frfree(f);
                                ast_clear_flag(c, AST_FLAG_END_DTMF_ONLY);
                                return res;
                        case AST_FRAME_CONTROL:
                                switch (f->subclass.integer) {
                                case AST_CONTROL_HANGUP:
                                        ast_frfree(f);
                                        ast_clear_flag(c, AST_FLAG_END_DTMF_ONLY);
                                        return -1;
                                case AST_CONTROL_RINGING:
                                case AST_CONTROL_ANSWER:
                                case AST_CONTROL_SRCUPDATE:
                                case AST_CONTROL_CONNECTED_LINE:
                                case AST_CONTROL_REDIRECTING:
                                        /* Unimportant */
                                        break;
                                default:
                                        ast_log(LOG_WARNING, "Unexpected control subclass '%d'\n", f->subclass.integer);
                                        break;
                                }
                                break;
                        case AST_FRAME_VOICE:
                                /* Write audio if appropriate */
                                if (audiofd > -1) {
                                        if (write(audiofd, f->data.ptr, f->datalen) < 0) {
                                                ast_log(LOG_WARNING, "write() failed: %s\n", strerror(errno));
                                        }
                                }
                        default:
                                /* Ignore */
                                break;
                        }
                        ast_frfree(f);
                }
        }

        ast_clear_flag(c, AST_FLAG_END_DTMF_ONLY);

        return 0; /* Time is up */
}

static void send_dtmf_event(struct ast_channel *chan, const char *direction, const char digit, const char *begin, const char *end)
{
        ast_manager_event(chan, EVENT_FLAG_DTMF,
                        "DTMF",
                        "Channel: %s\r\n"
                        "Uniqueid: %s\r\n"
                        "Digit: %c\r\n"
                        "Direction: %s\r\n"
                        "Begin: %s\r\n"
                        "End: %s\r\n",
                        chan->name, chan->uniqueid, digit, direction, begin, end);
}

static void ast_read_generator_actions(struct ast_channel *chan, struct ast_frame *f)
{
        if (chan->generator && chan->generator->generate && chan->generatordata &&  !ast_internal_timing_enabled(chan)) {
                void *tmp = chan->generatordata;
                int (*generate)(struct ast_channel *chan, void *tmp, int datalen, int samples) = chan->generator->generate;
                int res;
                int samples;

                if (chan->timingfunc) {
                        ast_debug(1, "Generator got voice, switching to phase locked mode\n");
                        ast_settimeout(chan, 0, NULL, NULL);
                }

                chan->generatordata = NULL;     /* reset, to let writes go through */

                if (f->subclass.codec != chan->writeformat) {
                        float factor;
                        factor = ((float) ast_format_rate(chan->writeformat)) / ((float) ast_format_rate(f->subclass.codec));
                        samples = (int) ( ((float) f->samples) * factor );
                } else {
                        samples = f->samples;
                }
                
                /* This unlock is here based on two assumptions that hold true at this point in the
                 * code. 1) this function is only called from within __ast_read() and 2) all generators
                 * call ast_write() in their generate callback.
                 *
                 * The reason this is added is so that when ast_write is called, the lock that occurs 
                 * there will not recursively lock the channel. Doing this will cause intended deadlock 
                 * avoidance not to work in deeper functions
                 */
                ast_channel_unlock(chan);
                res = generate(chan, tmp, f->datalen, samples);
                ast_channel_lock(chan);
                chan->generatordata = tmp;
                if (res) {
                        ast_debug(1, "Auto-deactivating generator\n");
                        ast_deactivate_generator(chan);
                }

        } else if (f->frametype == AST_FRAME_CNG) {
                if (chan->generator && !chan->timingfunc && (chan->timingfd > -1)) {
                        ast_debug(1, "Generator got CNG, switching to timed mode\n");
                        ast_settimeout(chan, 50, generator_force, chan);
                }
        }
}

static inline void queue_dtmf_readq(struct ast_channel *chan, struct ast_frame *f)
{
        struct ast_frame *fr = &chan->dtmff;

        fr->frametype = AST_FRAME_DTMF_END;
        fr->subclass.integer = f->subclass.integer;
        fr->len = f->len;

        /* The only time this function will be called is for a frame that just came
         * out of the channel driver.  So, we want to stick it on the tail of the
         * readq. */

        ast_queue_frame(chan, fr);
}

/*!
 * \brief Determine whether or not we should ignore DTMF in the readq
 */
static inline int should_skip_dtmf(struct ast_channel *chan)
{
        if (ast_test_flag(chan, AST_FLAG_DEFER_DTMF | AST_FLAG_EMULATE_DTMF)) {
                /* We're in the middle of emulating a digit, or DTMF has been
                 * explicitly deferred.  Skip this digit, then. */
                return 1;
        }
                        
        if (!ast_tvzero(chan->dtmf_tv) && 
                        ast_tvdiff_ms(ast_tvnow(), chan->dtmf_tv) < AST_MIN_DTMF_GAP) {
                /* We're not in the middle of a digit, but it hasn't been long enough
                 * since the last digit, so we'll have to skip DTMF for now. */
                return 1;
        }

        return 0;
}

static struct ast_frame *__ast_read(struct ast_channel *chan, int dropaudio)
{
        struct ast_frame *f = NULL;     /* the return value */
        int blah;
        int prestate;
        int cause = 0;

        /* this function is very long so make sure there is only one return
         * point at the end (there are only two exceptions to this).
         */

        if (chan->masq) {
                if (ast_do_masquerade(chan))
                        ast_log(LOG_WARNING, "Failed to perform masquerade\n");
                else
                        f =  &ast_null_frame;
                return f;
        }

        /* if here, no masq has happened, lock the channel and proceed */
        ast_channel_lock(chan);

        /* Stop if we're a zombie or need a soft hangup */
        if (ast_test_flag(chan, AST_FLAG_ZOMBIE) || ast_check_hangup(chan)) {
                if (chan->generator)
                        ast_deactivate_generator(chan);
                goto done;
        }

#ifdef AST_DEVMODE
        /* 
         * The ast_waitfor() code records which of the channel's file descriptors reported that
         * data is available.  In theory, ast_read() should only be called after ast_waitfor()
         * reports that a channel has data available for reading.  However, there still may be
         * some edge cases throughout the code where ast_read() is called improperly.  This can
         * potentially cause problems, so if this is a developer build, make a lot of noise if
         * this happens so that it can be addressed. 
         */
        if (chan->fdno == -1) {
                ast_log(LOG_ERROR, "ast_read() called with no recorded file descriptor.\n");
        }
#endif

        prestate = chan->_state;

        /* Read and ignore anything on the alertpipe, but read only
           one sizeof(blah) per frame that we send from it */
        if (chan->alertpipe[0] > -1) {
                int flags = fcntl(chan->alertpipe[0], F_GETFL);
                /* For some odd reason, the alertpipe occasionally loses nonblocking status,
                 * which immediately causes a deadlock scenario.  Detect and prevent this. */
                if ((flags & O_NONBLOCK) == 0) {
                        ast_log(LOG_ERROR, "Alertpipe on channel %s lost O_NONBLOCK?!!\n", chan->name);
                        if (fcntl(chan->alertpipe[0], F_SETFL, flags | O_NONBLOCK) < 0) {
                                ast_log(LOG_WARNING, "Unable to set alertpipe nonblocking! (%d: %s)\n", errno, strerror(errno));
                                f = &ast_null_frame;
                                goto done;
                        }
                }
                if (read(chan->alertpipe[0], &blah, sizeof(blah)) < 0) {
                        if (errno != EINTR && errno != EAGAIN)
                                ast_log(LOG_WARNING, "read() failed: %s\n", strerror(errno));
                }
        }

        if (chan->timingfd > -1 && chan->fdno == AST_TIMING_FD) {
                enum ast_timer_event res;

                ast_clear_flag(chan, AST_FLAG_EXCEPTION);

                res = ast_timer_get_event(chan->timer);

                switch (res) {
                case AST_TIMING_EVENT_EXPIRED:
                        ast_timer_ack(chan->timer, 1);

                        if (chan->timingfunc) {
                                /* save a copy of func/data before unlocking the channel */
                                int (*func)(const void *) = chan->timingfunc;
                                void *data = chan->timingdata;
                                chan->fdno = -1;
                                ast_channel_unlock(chan);
                                func(data);
                        } else {
                                ast_timer_set_rate(chan->timer, 0);
                                chan->fdno = -1;
                                ast_channel_unlock(chan);
                        }

                        /* cannot 'goto done' because the channel is already unlocked */
                        return &ast_null_frame;

                case AST_TIMING_EVENT_CONTINUOUS:
                        if (AST_LIST_EMPTY(&chan->readq) || 
                                !AST_LIST_NEXT(AST_LIST_FIRST(&chan->readq), frame_list)) {
                                ast_timer_disable_continuous(chan->timer);
                        }
                        break;
                }

        } else if (chan->fds[AST_GENERATOR_FD] > -1 && chan->fdno == AST_GENERATOR_FD) {
                /* if the AST_GENERATOR_FD is set, call the generator with args
                 * set to -1 so it can do whatever it needs to.
                 */
                void *tmp = chan->generatordata;
                chan->generatordata = NULL;     /* reset to let ast_write get through */
                chan->generator->generate(chan, tmp, -1, -1);
                chan->generatordata = tmp;
                f = &ast_null_frame;
                chan->fdno = -1;
                goto done;
        }

        /* Check for pending read queue */
        if (!AST_LIST_EMPTY(&chan->readq)) {
                int skip_dtmf = should_skip_dtmf(chan);

                AST_LIST_TRAVERSE_SAFE_BEGIN(&chan->readq, f, frame_list) {
                        /* We have to be picky about which frame we pull off of the readq because
                         * there are cases where we want to leave DTMF frames on the queue until
                         * some later time. */

                        if ( (f->frametype == AST_FRAME_DTMF_BEGIN || f->frametype == AST_FRAME_DTMF_END) && skip_dtmf) {
                                continue;
                        }

                        AST_LIST_REMOVE_CURRENT(frame_list);
                        break;
                }
                AST_LIST_TRAVERSE_SAFE_END;
                
                if (!f) {
                        /* There were no acceptable frames on the readq. */
                        f = &ast_null_frame;
                        if (chan->alertpipe[0] > -1) {
                                int poke = 0;
                                /* Restore the state of the alertpipe since we aren't ready for any
                                 * of the frames in the readq. */
                                if (write(chan->alertpipe[1], &poke, sizeof(poke)) != sizeof(poke)) {
                                        ast_log(LOG_ERROR, "Failed to write to alertpipe: %s\n", strerror(errno));
                                }
                        }
                }

                /* Interpret hangup and return NULL */
                /* XXX why not the same for frames from the channel ? */
                if (f->frametype == AST_FRAME_CONTROL && f->subclass.integer == AST_CONTROL_HANGUP) {
                        cause = f->data.uint32;
                        ast_frfree(f);
                        f = NULL;
                }
        } else {
                chan->blocker = pthread_self();
                if (ast_test_flag(chan, AST_FLAG_EXCEPTION)) {
                        if (chan->tech->exception)
                                f = chan->tech->exception(chan);
                        else {
                                ast_log(LOG_WARNING, "Exception flag set on '%s', but no exception handler\n", chan->name);
                                f = &ast_null_frame;
                        }
                        /* Clear the exception flag */
                        ast_clear_flag(chan, AST_FLAG_EXCEPTION);
                } else if (chan->tech->read)
                        f = chan->tech->read(chan);
                else
                        ast_log(LOG_WARNING, "No read routine on channel %s\n", chan->name);
        }

        /*
         * Reset the recorded file descriptor that triggered this read so that we can
         * easily detect when ast_read() is called without properly using ast_waitfor().
         */
        chan->fdno = -1;

        if (f) {
                struct ast_frame *readq_tail = AST_LIST_LAST(&chan->readq);

                /* if the channel driver returned more than one frame, stuff the excess
                   into the readq for the next ast_read call
                */
                if (AST_LIST_NEXT(f, frame_list)) {
                        ast_queue_frame(chan, AST_LIST_NEXT(f, frame_list));
                        ast_frfree(AST_LIST_NEXT(f, frame_list));
                        AST_LIST_NEXT(f, frame_list) = NULL;
                }

                switch (f->frametype) {
                case AST_FRAME_CONTROL:
                        if (f->subclass.integer == AST_CONTROL_ANSWER) {
                                if (!ast_test_flag(chan, AST_FLAG_OUTGOING)) {
                                        ast_debug(1, "Ignoring answer on an inbound call!\n");
                                        ast_frfree(f);
                                        f = &ast_null_frame;
                                } else if (prestate == AST_STATE_UP) {
                                        ast_debug(1, "Dropping duplicate answer!\n");
                                        ast_frfree(f);
                                        f = &ast_null_frame;
                                } else {
                                        /* Answer the CDR */
                                        ast_setstate(chan, AST_STATE_UP);
                                        /* removed a call to ast_cdr_answer(chan->cdr) from here. */
                                        ast_cel_report_event(chan, AST_CEL_ANSWER, NULL, NULL, NULL);
                                }
                        }
                        break;
                case AST_FRAME_DTMF_END:
                        send_dtmf_event(chan, "Received", f->subclass.integer, "No", "Yes");
                        ast_log(LOG_DTMF, "DTMF end '%c' received on %s, duration %ld ms\n", f->subclass.integer, chan->name, f->len);
                        /* Queue it up if DTMF is deferred, or if DTMF emulation is forced. */
                        if (ast_test_flag(chan, AST_FLAG_DEFER_DTMF) || ast_test_flag(chan, AST_FLAG_EMULATE_DTMF)) {
                                queue_dtmf_readq(chan, f);
                                ast_frfree(f);
                                f = &ast_null_frame;
                        } else if (!ast_test_flag(chan, AST_FLAG_IN_DTMF | AST_FLAG_END_DTMF_ONLY)) {