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app_chanisavail.c

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00001 /*
00002 * Asterisk -- An open source telephony toolkit.
00003 *
00004 * Copyright (C) 1999 - 2005, Digium, Inc.
00005 *
00006 * Mark Spencer <markster@digium.com>
00007 * James Golovich <james@gnuinter.net>
00008 *
00009 * See http://www.asterisk.org for more information about
00010 * the Asterisk project. Please do not directly contact
00011 * any of the maintainers of this project for assistance;
00012 * the project provides a web site, mailing lists and IRC
00013 * channels for your use.
00014 *
00015 * This program is free software, distributed under the terms of
00016 * the GNU General Public License Version 2. See the LICENSE file
00017 * at the top of the source tree.
00018 */
00019 
00020 /*! \file
00021 * \brief Check if Channel is Available
00022 * 
00023  * \ingroup applications
00024  */
00025 
00026 #include <stdlib.h>
00027 #include <stdio.h>
00028 #include <string.h>
00029 #include <unistd.h>
00030 #include <errno.h>
00031 #include <sys/ioctl.h>
00032 
00033 #include "asterisk.h"
00034 
00035 ASTERISK_FILE_VERSION(__FILE__, "$Revision: 7221 $")
00036 
00037 #include "asterisk/lock.h"
00038 #include "asterisk/file.h"
00039 #include "asterisk/logger.h"
00040 #include "asterisk/channel.h"
00041 #include "asterisk/pbx.h"
00042 #include "asterisk/module.h"
00043 #include "asterisk/app.h"
00044 #include "asterisk/devicestate.h"
00045 #include "asterisk/options.h"
00046 
00047 static char *tdesc = "Check channel availability";
00048 
00049 static char *app = "ChanIsAvail";
00050 
00051 static char *synopsis = "Check channel availability";
00052 
00053 static char *descrip = 
00054 "  ChanIsAvail(Technology/resource[&Technology2/resource2...][|options]): \n"
00055 "This application will check to see if any of the specified channels are\n"
00056 "available. The following variables will be set by this application:\n"
00057 "  ${AVAILCHAN}     - the name of the available channel, if one exists\n"
00058 "  ${AVAILORIGCHAN} - the canonical channel name that was used to create the channel\n"
00059 "  ${AVAILSTATUS}   - the status code for the available channel\n"
00060 "  Options:\n"
00061 "    s - Consider the channel unavailable if the channel is in use at all\n"
00062 "    j - Support jumping to priority n+101 if no channel is available\n";
00063 
00064 STANDARD_LOCAL_USER;
00065 
00066 LOCAL_USER_DECL;
00067 
00068 static int chanavail_exec(struct ast_channel *chan, void *data)
00069 {
00070    int res=-1, inuse=-1, option_state=0, priority_jump=0;
00071    int status;
00072    struct localuser *u;
00073    char *info, tmp[512], trychan[512], *peers, *tech, *number, *rest, *cur, *options, *stringp;
00074    struct ast_channel *tempchan;
00075 
00076    if (ast_strlen_zero(data)) {
00077       ast_log(LOG_WARNING, "ChanIsAvail requires an argument (Zap/1&Zap/2)\n");
00078       return -1;
00079    }
00080 
00081    LOCAL_USER_ADD(u);
00082 
00083    info = ast_strdupa(data); 
00084    stringp = info;
00085    strsep(&stringp, "|");
00086    options = strsep(&stringp, "|");
00087    if (options) {
00088       if (strchr(options, 's'))
00089          option_state = 1;
00090       if (strchr(options, 'j'))
00091          priority_jump = 1;
00092    }
00093    peers = info;
00094    if (peers) {
00095       cur = peers;
00096       do {
00097          /* remember where to start next time */
00098          rest = strchr(cur, '&');
00099          if (rest) {
00100             *rest = 0;
00101             rest++;
00102          }
00103          tech = cur;
00104          number = strchr(tech, '/');
00105          if (!number) {
00106             ast_log(LOG_WARNING, "ChanIsAvail argument takes format ([technology]/[device])\n");
00107             LOCAL_USER_REMOVE(u);
00108             return -1;
00109          }
00110          *number = '\0';
00111          number++;
00112          
00113          if (option_state) {
00114             /* If the pbx says in use then don't bother trying further.
00115                This is to permit testing if someone's on a call, even if the 
00116                channel can permit more calls (ie callwaiting, sip calls, etc).  */
00117                                
00118             snprintf(trychan, sizeof(trychan), "%s/%s",cur,number);
00119             status = inuse = ast_device_state(trychan);
00120          }
00121          if ((inuse <= 1) && (tempchan = ast_request(tech, chan->nativeformats, number, &status))) {
00122                pbx_builtin_setvar_helper(chan, "AVAILCHAN", tempchan->name);
00123                /* Store the originally used channel too */
00124                snprintf(tmp, sizeof(tmp), "%s/%s", tech, number);
00125                pbx_builtin_setvar_helper(chan, "AVAILORIGCHAN", tmp);
00126                snprintf(tmp, sizeof(tmp), "%d", status);
00127                pbx_builtin_setvar_helper(chan, "AVAILSTATUS", tmp);
00128                ast_hangup(tempchan);
00129                tempchan = NULL;
00130                res = 1;
00131                break;
00132          } else {
00133             snprintf(tmp, sizeof(tmp), "%d", status);
00134             pbx_builtin_setvar_helper(chan, "AVAILSTATUS", tmp);
00135          }
00136          cur = rest;
00137       } while (cur);
00138    }
00139    if (res < 1) {
00140       pbx_builtin_setvar_helper(chan, "AVAILCHAN", "");
00141       pbx_builtin_setvar_helper(chan, "AVAILORIGCHAN", "");
00142       if (priority_jump || option_priority_jumping) {
00143          if (ast_goto_if_exists(chan, chan->context, chan->exten, chan->priority + 101)) {
00144             LOCAL_USER_REMOVE(u);
00145             return -1;
00146          }
00147       }
00148    }
00149 
00150    LOCAL_USER_REMOVE(u);
00151    return 0;
00152 }
00153 
00154 int unload_module(void)
00155 {
00156    int res = 0;
00157 
00158    res = ast_unregister_application(app);
00159 
00160    STANDARD_HANGUP_LOCALUSERS;
00161    
00162    return res;
00163 }
00164 
00165 int load_module(void)
00166 {
00167    return ast_register_application(app, chanavail_exec, synopsis, descrip);
00168 }
00169 
00170 char *description(void)
00171 {
00172    return tdesc;
00173 }
00174 
00175 int usecount(void)
00176 {
00177    int res;
00178    STANDARD_USECOUNT(res);
00179    return res;
00180 }
00181 
00182 char *key()
00183 {
00184    return ASTERISK_GPL_KEY;
00185 }

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