Tue Nov 16 17:07:36 2010

Asterisk developer's documentation


autoservice.c File Reference

Automatic channel service routines. More...

#include "asterisk.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/time.h>
#include <signal.h>
#include <errno.h>
#include <unistd.h>
#include "asterisk/pbx.h"
#include "asterisk/frame.h"
#include "asterisk/sched.h"
#include "asterisk/options.h"
#include "asterisk/channel.h"
#include "asterisk/logger.h"
#include "asterisk/file.h"
#include "asterisk/translate.h"
#include "asterisk/manager.h"
#include "asterisk/chanvars.h"
#include "asterisk/linkedlists.h"
#include "asterisk/indications.h"
#include "asterisk/lock.h"
#include "asterisk/utils.h"

Go to the source code of this file.

Data Structures

struct  asent
struct  aslist

Defines

#define MAX_AUTOMONS   1500

Functions

void ast_autoservice_init (void)
int ast_autoservice_start (struct ast_channel *chan)
 Automatically service a channel for us...
int ast_autoservice_stop (struct ast_channel *chan)
 Stop servicing a channel for us...
static void * autoservice_run (void *ign)

Variables

static int as_chan_list_state
static ast_cond_t as_cond
static pthread_t asthread = AST_PTHREADT_NULL


Detailed Description

Automatic channel service routines.

Author:
Mark Spencer <markster@digium.com>

Russell Bryant <russell@digium.com>

Definition in file autoservice.c.


Define Documentation

#define MAX_AUTOMONS   1500

Definition at line 55 of file autoservice.c.

Referenced by autoservice_run().


Function Documentation

void ast_autoservice_init ( void   ) 

Provided by astobj2.c Provided by autoservice.c

Definition at line 324 of file autoservice.c.

References as_cond, and ast_cond_init().

Referenced by main().

00325 {
00326    ast_cond_init(&as_cond, NULL);
00327 }

int ast_autoservice_start ( struct ast_channel chan  ) 

Automatically service a channel for us...

Return values:
0 success
-1 failure, or the channel is already being autoserviced

Definition at line 197 of file autoservice.c.

References as_cond, ast_calloc, ast_channel_lock, ast_channel_unlock, ast_cond_signal(), AST_FLAG_END_DTMF_ONLY, AST_LIST_EMPTY, AST_LIST_INSERT_HEAD, AST_LIST_LOCK, AST_LIST_REMOVE, AST_LIST_TRAVERSE, AST_LIST_UNLOCK, ast_log(), ast_pthread_create_background, AST_PTHREADT_NULL, ast_set_flag, ast_test_flag, asthread, autoservice_run(), asent::chan, free, asent::list, LOG_WARNING, and asent::use_count.

Referenced by _macro_exec(), acf_curl_exec(), acf_odbc_read(), acf_odbc_write(), ast_dtmf_stream(), ast_get_enum(), ast_get_srv(), ast_get_txt(), bridge_playfile(), builtin_automonitor(), builtin_blindtransfer(), conf_play(), do_atxfer(), feature_exec_app(), function_realtime_read(), function_realtime_write(), osplookup_exec(), sla_station_exec(), smdi_msg_retrieve_read(), and system_exec_helper().

00198 {
00199    int res = 0;
00200    struct asent *as;
00201 
00202    /* Check if the channel already has autoservice */
00203    AST_LIST_LOCK(&aslist);
00204    AST_LIST_TRAVERSE(&aslist, as, list) {
00205       if (as->chan == chan) {
00206          as->use_count++;
00207          break;
00208       }
00209    }
00210    AST_LIST_UNLOCK(&aslist);
00211 
00212    if (as) {
00213       /* Entry exists, autoservice is already handling this channel */
00214       return 0;
00215    }
00216 
00217    if (!(as = ast_calloc(1, sizeof(*as))))
00218       return -1;
00219    
00220    /* New entry created */
00221    as->chan = chan;
00222    as->use_count = 1;
00223 
00224    ast_channel_lock(chan);
00225    as->orig_end_dtmf_flag = ast_test_flag(chan, AST_FLAG_END_DTMF_ONLY) ? 1 : 0;
00226    if (!as->orig_end_dtmf_flag)
00227       ast_set_flag(chan, AST_FLAG_END_DTMF_ONLY);
00228    ast_channel_unlock(chan);
00229 
00230    AST_LIST_LOCK(&aslist);
00231 
00232    if (AST_LIST_EMPTY(&aslist) && asthread != AST_PTHREADT_NULL) {
00233       ast_cond_signal(&as_cond);
00234    }
00235 
00236    AST_LIST_INSERT_HEAD(&aslist, as, list);
00237 
00238    if (asthread == AST_PTHREADT_NULL) { /* need start the thread */
00239       if (ast_pthread_create_background(&asthread, NULL, autoservice_run, NULL)) {
00240          ast_log(LOG_WARNING, "Unable to create autoservice thread :(\n");
00241          /* There will only be a single member in the list at this point,
00242             the one we just added. */
00243          AST_LIST_REMOVE(&aslist, as, list);
00244          free(as);
00245          asthread = AST_PTHREADT_NULL;
00246          res = -1;
00247       } else {
00248          pthread_kill(asthread, SIGURG);
00249       }
00250    }
00251 
00252    AST_LIST_UNLOCK(&aslist);
00253 
00254    return res;
00255 }

int ast_autoservice_stop ( struct ast_channel chan  ) 

Stop servicing a channel for us...

Note:
if chan is locked prior to calling ast_autoservice_stop, it is likely that there will be a deadlock between the thread that calls ast_autoservice_stop and the autoservice thread. It is important that chan is not locked prior to this call
Return values:
0 success
-1 error, or the channel has been hungup

Definition at line 257 of file autoservice.c.

References ast_channel::_softhangup, as_chan_list_state, ast_channel_lock, ast_channel_unlock, ast_clear_flag, AST_FLAG_END_DTMF_ONLY, ast_frfree, AST_LIST_LOCK, AST_LIST_REMOVE_CURRENT, AST_LIST_REMOVE_HEAD, AST_LIST_TRAVERSE_SAFE_BEGIN, AST_LIST_TRAVERSE_SAFE_END, AST_LIST_UNLOCK, AST_PTHREADT_NULL, ast_queue_frame_head(), asthread, asent::chan, asent::deferred_frames, f, ast_frame::frame_list, free, asent::list, asent::orig_end_dtmf_flag, and asent::use_count.

Referenced by _macro_exec(), acf_curl_exec(), acf_odbc_read(), acf_odbc_write(), ast_dtmf_stream(), ast_get_srv(), ast_get_txt(), ast_hangup(), bridge_playfile(), builtin_automonitor(), conf_play(), do_atxfer(), feature_exec_app(), finishup(), function_realtime_read(), function_realtime_write(), osplookup_exec(), sla_station_exec(), smdi_msg_retrieve_read(), and system_exec_helper().

00258 {
00259    int res = -1;
00260    struct asent *as, *removed = NULL;
00261    struct ast_frame *f;
00262    int chan_list_state;
00263 
00264    AST_LIST_LOCK(&aslist);
00265 
00266    /* Save the autoservice channel list state.  We _must_ verify that the channel
00267     * list has been rebuilt before we return.  Because, after we return, the channel
00268     * could get destroyed and we don't want our poor autoservice thread to step on
00269     * it after its gone! */
00270    chan_list_state = as_chan_list_state;
00271 
00272    /* Find the entry, but do not free it because it still can be in the
00273       autoservice thread array */
00274    AST_LIST_TRAVERSE_SAFE_BEGIN(&aslist, as, list) {  
00275       if (as->chan == chan) {
00276          as->use_count--;
00277          if (as->use_count < 1) {
00278             AST_LIST_REMOVE_CURRENT(&aslist, list);
00279             removed = as;
00280          }
00281          break;
00282       }
00283    }
00284    AST_LIST_TRAVERSE_SAFE_END
00285 
00286    if (removed && asthread != AST_PTHREADT_NULL) {
00287       pthread_kill(asthread, SIGURG);
00288    }
00289 
00290    AST_LIST_UNLOCK(&aslist);
00291 
00292    if (!removed) {
00293       return 0;
00294    }
00295 
00296    /* Wait while autoservice thread rebuilds its list. */
00297    while (chan_list_state == as_chan_list_state) {
00298       usleep(1000);
00299    }
00300 
00301    /* Now autoservice thread should have no references to our entry
00302       and we can safely destroy it */
00303 
00304    if (!chan->_softhangup) {
00305       res = 0;
00306    }
00307 
00308    if (!as->orig_end_dtmf_flag) {
00309       ast_clear_flag(chan, AST_FLAG_END_DTMF_ONLY);
00310    }
00311 
00312    ast_channel_lock(chan);
00313    while ((f = AST_LIST_REMOVE_HEAD(&as->deferred_frames, frame_list))) {
00314       ast_queue_frame_head(chan, f);
00315       ast_frfree(f);
00316    }
00317    ast_channel_unlock(chan);
00318 
00319    free(as);
00320 
00321    return res;
00322 }

static void* autoservice_run ( void *  ign  )  [static]

Definition at line 78 of file autoservice.c.

References ast_channel::_softhangup, ast_cond_wait(), AST_CONTROL_HANGUP, AST_FRAME_CNG, AST_FRAME_CONTROL, AST_FRAME_DTMF_BEGIN, AST_FRAME_DTMF_END, AST_FRAME_HTML, AST_FRAME_IAX, AST_FRAME_IMAGE, AST_FRAME_MODEM, AST_FRAME_NULL, AST_FRAME_TEXT, AST_FRAME_VIDEO, AST_FRAME_VOICE, ast_frdup(), ast_frfree, ast_frisolate(), AST_LIST_EMPTY, AST_LIST_INSERT_HEAD, AST_LIST_LOCK, AST_LIST_TRAVERSE, AST_LIST_UNLOCK, ast_log(), ast_read(), ast_waitfor_n(), asthread, asent::chan, asent::deferred_frames, f, ast_frame::frame_list, ast_frame::frametype, LOG_WARNING, and MAX_AUTOMONS.

Referenced by ast_autoservice_start().

00079 {
00080    struct ast_frame hangup_frame = {
00081       .frametype = AST_FRAME_CONTROL,
00082       .subclass = AST_CONTROL_HANGUP,
00083    };
00084 
00085    for (;;) {
00086       struct ast_channel *mons[MAX_AUTOMONS];
00087       struct asent *ents[MAX_AUTOMONS];
00088       struct ast_channel *chan;
00089       struct asent *as;
00090       int i, x = 0, ms = 50;
00091       struct ast_frame *f = NULL;
00092       struct ast_frame *defer_frame = NULL;
00093 
00094       AST_LIST_LOCK(&aslist);
00095 
00096       /* At this point, we know that no channels that have been removed are going
00097        * to get used again. */
00098       as_chan_list_state++;
00099 
00100       if (AST_LIST_EMPTY(&aslist)) {
00101          ast_cond_wait(&as_cond, &aslist.lock);
00102       }
00103 
00104       AST_LIST_TRAVERSE(&aslist, as, list) {
00105          if (!as->chan->_softhangup) {
00106             if (x < MAX_AUTOMONS) {
00107                ents[x] = as;
00108                mons[x++] = as->chan;
00109             } else {
00110                ast_log(LOG_WARNING, "Exceeded maximum number of automatic monitoring events.  Fix autoservice.c\n");
00111             }
00112          }
00113       }
00114 
00115       AST_LIST_UNLOCK(&aslist);
00116 
00117       if (!x) {
00118          continue;
00119       }
00120 
00121       chan = ast_waitfor_n(mons, x, &ms);
00122       if (!chan) {
00123          continue;
00124       }
00125 
00126       f = ast_read(chan);
00127 
00128       if (!f) {
00129          /* No frame means the channel has been hung up.
00130           * A hangup frame needs to be queued here as ast_waitfor() may
00131           * never return again for the condition to be detected outside
00132           * of autoservice.  So, we'll leave a HANGUP queued up so the
00133           * thread in charge of this channel will know. */
00134 
00135          defer_frame = &hangup_frame;
00136       } else {
00137 
00138          /* Do not add a default entry in this switch statement.  Each new
00139           * frame type should be addressed directly as to whether it should
00140           * be queued up or not. */
00141 
00142          switch (f->frametype) {
00143          /* Save these frames */
00144          case AST_FRAME_DTMF_END:
00145          case AST_FRAME_CONTROL:
00146          case AST_FRAME_TEXT:
00147          case AST_FRAME_IMAGE:
00148          case AST_FRAME_HTML:
00149             defer_frame = f;
00150             break;
00151 
00152          /* Throw these frames away */
00153          case AST_FRAME_DTMF_BEGIN:
00154          case AST_FRAME_VOICE:
00155          case AST_FRAME_VIDEO:
00156          case AST_FRAME_NULL:
00157          case AST_FRAME_IAX:
00158          case AST_FRAME_CNG:
00159          case AST_FRAME_MODEM:
00160             break;
00161          }
00162       }
00163 
00164       if (defer_frame) {
00165          for (i = 0; i < x; i++) {
00166             struct ast_frame *dup_f;
00167             
00168             if (mons[i] != chan) {
00169                continue;
00170             }
00171             
00172             if (defer_frame != f) {
00173                if ((dup_f = ast_frdup(defer_frame))) {
00174                   AST_LIST_INSERT_HEAD(&ents[i]->deferred_frames, dup_f, frame_list);
00175                }
00176             } else {
00177                if ((dup_f = ast_frisolate(defer_frame))) {
00178                   if (dup_f != defer_frame) {
00179                      ast_frfree(defer_frame);
00180                   }
00181                   AST_LIST_INSERT_HEAD(&ents[i]->deferred_frames, dup_f, frame_list);
00182                }
00183             }
00184             
00185             break;
00186          }
00187       } else if (f) {
00188          ast_frfree(f);
00189       }
00190    }
00191 
00192    asthread = AST_PTHREADT_NULL;
00193 
00194    return NULL;
00195 }


Variable Documentation

int as_chan_list_state [static]

Definition at line 76 of file autoservice.c.

Referenced by ast_autoservice_stop().

ast_cond_t as_cond [static]

Definition at line 72 of file autoservice.c.

Referenced by ast_autoservice_init(), and ast_autoservice_start().

pthread_t asthread = AST_PTHREADT_NULL [static]

Definition at line 74 of file autoservice.c.

Referenced by ast_autoservice_start(), ast_autoservice_stop(), and autoservice_run().


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