Fri Jul 24 00:41:18 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 310 of file autoservice.c.

References as_cond, and ast_cond_init().

Referenced by main().

00311 {
00312    ast_cond_init(&as_cond, NULL);
00313 }

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 184 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_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(), play_message_in_bridged_call(), shell_helper(), sla_station_exec(), smdi_msg_retrieve_read(), system_exec_helper(), try_calling(), and trylock_read().

00185 {
00186    int res = 0;
00187    struct asent *as;
00188 
00189    AST_LIST_LOCK(&aslist);
00190    AST_LIST_TRAVERSE(&aslist, as, list) {
00191       if (as->chan == chan) {
00192          as->use_count++;
00193          break;
00194       }
00195    }
00196    AST_LIST_UNLOCK(&aslist);
00197 
00198    if (as) {
00199       /* Entry exists, autoservice is already handling this channel */
00200       return 0;
00201    }
00202 
00203    if (!(as = ast_calloc(1, sizeof(*as))))
00204       return -1;
00205    
00206    /* New entry created */
00207    as->chan = chan;
00208    as->use_count = 1;
00209 
00210    ast_channel_lock(chan);
00211    as->orig_end_dtmf_flag = ast_test_flag(chan, AST_FLAG_END_DTMF_ONLY) ? 1 : 0;
00212    if (!as->orig_end_dtmf_flag)
00213       ast_set_flag(chan, AST_FLAG_END_DTMF_ONLY);
00214    ast_channel_unlock(chan);
00215 
00216    AST_LIST_LOCK(&aslist);
00217 
00218    if (AST_LIST_EMPTY(&aslist) && asthread != AST_PTHREADT_NULL) {
00219       ast_cond_signal(&as_cond);
00220    }
00221 
00222    AST_LIST_INSERT_HEAD(&aslist, as, list);
00223 
00224    if (asthread == AST_PTHREADT_NULL) { /* need start the thread */
00225       if (ast_pthread_create_background(&asthread, NULL, autoservice_run, NULL)) {
00226          ast_log(LOG_WARNING, "Unable to create autoservice thread :(\n");
00227          /* There will only be a single member in the list at this point,
00228             the one we just added. */
00229          AST_LIST_REMOVE(&aslist, as, list);
00230          free(as);
00231          asthread = AST_PTHREADT_NULL;
00232          res = -1;
00233       } else {
00234          pthread_kill(asthread, SIGURG);
00235       }
00236    }
00237 
00238    AST_LIST_UNLOCK(&aslist);
00239 
00240    return res;
00241 }

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 243 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(), 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(), play_message_in_bridged_call(), shell_helper(), sla_station_exec(), smdi_msg_retrieve_read(), system_exec_helper(), try_calling(), and trylock_read().

00244 {
00245    int res = -1;
00246    struct asent *as, *removed = NULL;
00247    struct ast_frame *f;
00248    int chan_list_state;
00249 
00250    AST_LIST_LOCK(&aslist);
00251 
00252    /* Save the autoservice channel list state.  We _must_ verify that the channel
00253     * list has been rebuilt before we return.  Because, after we return, the channel
00254     * could get destroyed and we don't want our poor autoservice thread to step on
00255     * it after its gone! */
00256    chan_list_state = as_chan_list_state;
00257 
00258    /* Find the entry, but do not free it because it still can be in the
00259       autoservice thread array */
00260    AST_LIST_TRAVERSE_SAFE_BEGIN(&aslist, as, list) {  
00261       if (as->chan == chan) {
00262          as->use_count--;
00263          if (as->use_count < 1) {
00264             AST_LIST_REMOVE_CURRENT(list);
00265             removed = as;
00266          }
00267          break;
00268       }
00269    }
00270    AST_LIST_TRAVERSE_SAFE_END;
00271 
00272    if (removed && asthread != AST_PTHREADT_NULL) {
00273       pthread_kill(asthread, SIGURG);
00274    }
00275 
00276    AST_LIST_UNLOCK(&aslist);
00277 
00278    if (!removed) {
00279       return 0;
00280    }
00281 
00282    /* Wait while autoservice thread rebuilds its list. */
00283    while (chan_list_state == as_chan_list_state) {
00284       usleep(1000);
00285    }
00286 
00287    /* Now autoservice thread should have no references to our entry
00288       and we can safely destroy it */
00289 
00290    if (!chan->_softhangup) {
00291       res = 0;
00292    }
00293 
00294    if (!as->orig_end_dtmf_flag) {
00295       ast_clear_flag(chan, AST_FLAG_END_DTMF_ONLY);
00296    }
00297 
00298    ast_channel_lock(chan);
00299    while ((f = AST_LIST_REMOVE_HEAD(&as->deferred_frames, frame_list))) {
00300       ast_queue_frame_head(chan, f);
00301       ast_frfree(f);
00302    }
00303    ast_channel_unlock(chan);
00304 
00305    free(as);
00306 
00307    return res;
00308 }

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_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 ((dup_f = ast_frdup(defer_frame))) {
00167                AST_LIST_INSERT_HEAD(&ents[i]->deferred_frames, dup_f, frame_list);
00168             }
00169             
00170             break;
00171          }
00172       }
00173 
00174       if (f) {
00175          ast_frfree(f);
00176       }
00177    }
00178 
00179    asthread = AST_PTHREADT_NULL;
00180 
00181    return NULL;
00182 }


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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