Thu Jul 9 13:40:53 2009

Asterisk developer's documentation


autoservice.c File Reference

Automatic channel service routines. More...

#include "asterisk.h"
#include <sys/time.h>
#include <signal.h>
#include "asterisk/_private.h"
#include "asterisk/pbx.h"
#include "asterisk/frame.h"
#include "asterisk/sched.h"
#include "asterisk/channel.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 50 of file autoservice.c.

Referenced by autoservice_run().


Function Documentation

void ast_autoservice_init ( void   ) 

Provided by autoservice.c

Definition at line 317 of file autoservice.c.

References as_cond, and ast_cond_init().

Referenced by main().

00318 {
00319    ast_cond_init(&as_cond, NULL);
00320 }

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 191 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_atxfer(), builtin_automixmonitor(), builtin_automonitor(), builtin_blindtransfer(), conf_play(), dial_exec_full(), feature_exec_app(), function_realtime_read(), function_realtime_readdestroy(), function_realtime_store(), function_realtime_write(), lock_read(), lua_autoservice_start(), lua_get_variable_value(), lua_pbx_exec(), lua_set_variable(), lua_set_variable_value(), osplookup_exec(), pbx_find_extension(), shell_helper(), sla_station_exec(), smdi_msg_retrieve_read(), system_exec_helper(), and trylock_read().

00192 {
00193    int res = 0;
00194    struct asent *as;
00195 
00196    AST_LIST_LOCK(&aslist);
00197    AST_LIST_TRAVERSE(&aslist, as, list) {
00198       if (as->chan == chan) {
00199          as->use_count++;
00200          break;
00201       }
00202    }
00203    AST_LIST_UNLOCK(&aslist);
00204 
00205    if (as) {
00206       /* Entry exists, autoservice is already handling this channel */
00207       return 0;
00208    }
00209 
00210    if (!(as = ast_calloc(1, sizeof(*as))))
00211       return -1;
00212    
00213    /* New entry created */
00214    as->chan = chan;
00215    as->use_count = 1;
00216 
00217    ast_channel_lock(chan);
00218    as->orig_end_dtmf_flag = ast_test_flag(chan, AST_FLAG_END_DTMF_ONLY) ? 1 : 0;
00219    if (!as->orig_end_dtmf_flag)
00220       ast_set_flag(chan, AST_FLAG_END_DTMF_ONLY);
00221    ast_channel_unlock(chan);
00222 
00223    AST_LIST_LOCK(&aslist);
00224 
00225    if (AST_LIST_EMPTY(&aslist) && asthread != AST_PTHREADT_NULL) {
00226       ast_cond_signal(&as_cond);
00227    }
00228 
00229    AST_LIST_INSERT_HEAD(&aslist, as, list);
00230 
00231    if (asthread == AST_PTHREADT_NULL) { /* need start the thread */
00232       if (ast_pthread_create_background(&asthread, NULL, autoservice_run, NULL)) {
00233          ast_log(LOG_WARNING, "Unable to create autoservice thread :(\n");
00234          /* There will only be a single member in the list at this point,
00235             the one we just added. */
00236          AST_LIST_REMOVE(&aslist, as, list);
00237          free(as);
00238          asthread = AST_PTHREADT_NULL;
00239          res = -1;
00240       } else {
00241          pthread_kill(asthread, SIGURG);
00242       }
00243    }
00244 
00245    AST_LIST_UNLOCK(&aslist);
00246 
00247    return res;
00248 }

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 250 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_write(), array(), ast_dtmf_stream(), ast_get_srv(), ast_get_txt(), ast_hangup(), bridge_playfile(), builtin_atxfer(), builtin_automixmonitor(), builtin_automonitor(), conf_play(), dial_exec_full(), feature_exec_app(), finishup(), function_realtime_read(), function_realtime_readdestroy(), function_realtime_store(), function_realtime_write(), lock_read(), lua_autoservice_stop(), lua_get_variable_value(), lua_pbx_exec(), lua_set_variable(), lua_set_variable_value(), osplookup_exec(), pbx_find_extension(), shell_helper(), sla_station_exec(), smdi_msg_retrieve_read(), system_exec_helper(), and trylock_read().

00251 {
00252    int res = -1;
00253    struct asent *as, *removed = NULL;
00254    struct ast_frame *f;
00255    int chan_list_state;
00256 
00257    AST_LIST_LOCK(&aslist);
00258 
00259    /* Save the autoservice channel list state.  We _must_ verify that the channel
00260     * list has been rebuilt before we return.  Because, after we return, the channel
00261     * could get destroyed and we don't want our poor autoservice thread to step on
00262     * it after its gone! */
00263    chan_list_state = as_chan_list_state;
00264 
00265    /* Find the entry, but do not free it because it still can be in the
00266       autoservice thread array */
00267    AST_LIST_TRAVERSE_SAFE_BEGIN(&aslist, as, list) {  
00268       if (as->chan == chan) {
00269          as->use_count--;
00270          if (as->use_count < 1) {
00271             AST_LIST_REMOVE_CURRENT(list);
00272             removed = as;
00273          }
00274          break;
00275       }
00276    }
00277    AST_LIST_TRAVERSE_SAFE_END;
00278 
00279    if (removed && asthread != AST_PTHREADT_NULL) {
00280       pthread_kill(asthread, SIGURG);
00281    }
00282 
00283    AST_LIST_UNLOCK(&aslist);
00284 
00285    if (!removed) {
00286       return 0;
00287    }
00288 
00289    /* Wait while autoservice thread rebuilds its list. */
00290    while (chan_list_state == as_chan_list_state) {
00291       usleep(1000);
00292    }
00293 
00294    /* Now autoservice thread should have no references to our entry
00295       and we can safely destroy it */
00296 
00297    if (!chan->_softhangup) {
00298       res = 0;
00299    }
00300 
00301    if (!as->orig_end_dtmf_flag) {
00302       ast_clear_flag(chan, AST_FLAG_END_DTMF_ONLY);
00303    }
00304 
00305    ast_channel_lock(chan);
00306    while ((f = AST_LIST_REMOVE_HEAD(&as->deferred_frames, frame_list))) {
00307       ast_queue_frame_head(chan, f);
00308       ast_frfree(f);
00309    }
00310    ast_channel_unlock(chan);
00311 
00312    free(as);
00313 
00314    return res;
00315 }

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

Definition at line 73 of file autoservice.c.

References ast_check_hangup(), 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, MAX_AUTOMONS, and ast_frame::subclass.

Referenced by ast_autoservice_start().

00074 {
00075    for (;;) {
00076       struct ast_channel *mons[MAX_AUTOMONS];
00077       struct asent *ents[MAX_AUTOMONS];
00078       struct ast_channel *chan;
00079       struct asent *as;
00080       int i, x = 0, ms = 50;
00081       struct ast_frame *f = NULL;
00082       struct ast_frame *defer_frame = NULL;
00083 
00084       AST_LIST_LOCK(&aslist);
00085 
00086       /* At this point, we know that no channels that have been removed are going
00087        * to get used again. */
00088       as_chan_list_state++;
00089 
00090       if (AST_LIST_EMPTY(&aslist)) {
00091          ast_cond_wait(&as_cond, &aslist.lock);
00092       }
00093 
00094       AST_LIST_TRAVERSE(&aslist, as, list) {
00095          if (!ast_check_hangup(as->chan)) {
00096             if (x < MAX_AUTOMONS) {
00097                ents[x] = as;
00098                mons[x++] = as->chan;
00099             } else {
00100                ast_log(LOG_WARNING, "Exceeded maximum number of automatic monitoring events.  Fix autoservice.c\n");
00101             }
00102          }
00103       }
00104 
00105       AST_LIST_UNLOCK(&aslist);
00106 
00107       if (!x) {
00108          continue;
00109       }
00110 
00111       chan = ast_waitfor_n(mons, x, &ms);
00112       if (!chan) {
00113          continue;
00114       }
00115 
00116       f = ast_read(chan);
00117    
00118       if (!f) {
00119          struct ast_frame hangup_frame = { 0, };
00120          /* No frame means the channel has been hung up.
00121           * A hangup frame needs to be queued here as ast_waitfor() may
00122           * never return again for the condition to be detected outside
00123           * of autoservice.  So, we'll leave a HANGUP queued up so the
00124           * thread in charge of this channel will know. */
00125 
00126          hangup_frame.frametype = AST_FRAME_CONTROL;
00127          hangup_frame.subclass = AST_CONTROL_HANGUP;
00128 
00129          defer_frame = &hangup_frame;
00130       } else {
00131 
00132          /* Do not add a default entry in this switch statement.  Each new
00133           * frame type should be addressed directly as to whether it should
00134           * be queued up or not. */
00135 
00136          switch (f->frametype) {
00137          /* Save these frames */
00138          case AST_FRAME_DTMF_END:
00139          case AST_FRAME_CONTROL:
00140          case AST_FRAME_TEXT:
00141          case AST_FRAME_IMAGE:
00142          case AST_FRAME_HTML:
00143             defer_frame = f;
00144             break;
00145 
00146          /* Throw these frames away */
00147          case AST_FRAME_DTMF_BEGIN:
00148          case AST_FRAME_VOICE:
00149          case AST_FRAME_VIDEO:
00150          case AST_FRAME_NULL:
00151          case AST_FRAME_IAX:
00152          case AST_FRAME_CNG:
00153          case AST_FRAME_MODEM:
00154             break;
00155          }
00156       }
00157 
00158       if (defer_frame) {
00159          for (i = 0; i < x; i++) {
00160             struct ast_frame *dup_f;
00161             
00162             if (mons[i] != chan) {
00163                continue;
00164             }
00165             
00166             if (defer_frame != f) {
00167                if ((dup_f = ast_frdup(defer_frame))) {
00168                   AST_LIST_INSERT_HEAD(&ents[i]->deferred_frames, dup_f, frame_list);
00169                }
00170             } else {
00171                if ((dup_f = ast_frisolate(defer_frame))) {
00172                   if (dup_f != defer_frame) {
00173                      ast_frfree(defer_frame);
00174                   }
00175                   AST_LIST_INSERT_HEAD(&ents[i]->deferred_frames, dup_f, frame_list);
00176                }
00177             }
00178             
00179             break;
00180          }
00181       } else if (f) {
00182          ast_frfree(f);
00183       }
00184    }
00185 
00186    asthread = AST_PTHREADT_NULL;
00187 
00188    return NULL;
00189 }


Variable Documentation

int as_chan_list_state [static]

Definition at line 71 of file autoservice.c.

Referenced by ast_autoservice_stop().

ast_cond_t as_cond [static]

Definition at line 67 of file autoservice.c.

Referenced by ast_autoservice_init(), and ast_autoservice_start().

pthread_t asthread = AST_PTHREADT_NULL [static]

Definition at line 69 of file autoservice.c.

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


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