apps/app_chanisavail.c

   1 /*
   2 * Asterisk -- An open source telephony toolkit.
   3 *
   4 * Copyright (C) 1999 - 2005, Digium, Inc.
   5 *
   6 * Mark Spencer <markster@digium.com>
   7 * James Golovich <james@gnuinter.net>
   8 *
   9 * See http://www.asterisk.org for more information about
  10 * the Asterisk project. Please do not directly contact
  11 * any of the maintainers of this project for assistance;
  12 * the project provides a web site, mailing lists and IRC
  13 * channels for your use.
  14 *
  15 * This program is free software, distributed under the terms of
  16 * the GNU General Public License Version 2. See the LICENSE file
  17 * at the top of the source tree.
  18 */
  19
  20 /*! \file
  21  *
  22  * \brief Check if Channel is Available
  23  *
  24  * \author Mark Spencer <markster@digium.com>
  25  * \author James Golovich <james@gnuinter.net>
  26
  27  * \ingroup applications
  28  */
  29
  30 #include "asterisk.h"
  31
  32 ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
  33
  34 #include <sys/ioctl.h>
  35
  36 #include "asterisk/lock.h"
  37 #include "asterisk/file.h"
  38 #include "asterisk/channel.h"
  39 #include "asterisk/pbx.h"
  40 #include "asterisk/module.h"
  41 #include "asterisk/app.h"
  42 #include "asterisk/devicestate.h"
  43
  44 static const char app[] = "ChanIsAvail";
  45
  46 /*** DOCUMENTATION
  47         <application name="ChanIsAvail" language="en_US">
  48                 <synopsis>
  49                         Check channel availability
  50                 </synopsis>
  51                 <syntax>
  52                         <parameter name="Technology/Resource" required="true" argsep="&amp;">
  53                                 <argument name="Technology2/Resource2" multiple="true">
  54                                         <para>Optional extra devices to check</para>
  55                                         <para>If you need more then one enter them as
  56                                         Technology2/Resource2&amp;Technology3/Resourse3&amp;.....</para>
  57                                 </argument>
  58                                 <para>Specification of the device(s) to check.  These must be in the format of
  59                                 <literal>Technology/Resource</literal>, where <replaceable>Technology</replaceable>
  60                                 represents a particular channel driver, and <replaceable>Resource</replaceable>
  61                                 represents a resource available to that particular channel driver.</para>
  62                         </parameter>
  63                         <parameter name="options" required="false">
  64                                 <optionlist>
  65                                         <option name="a">
  66                                                 <para>Check for all available channels, not only the first one</para>
  67                                         </option>
  68                                         <option name="s">
  69                                                 <para>Consider the channel unavailable if the channel is in use at all</para>
  70                                         </option>
  71                                         <option name="t" implies="s">
  72                                                 <para>Simply checks if specified channels exist in the channel list</para>
  73                                         </option>
  74                                 </optionlist>
  75                         </parameter>
  76                 </syntax>
  77                 <description>
  78                         <para>This application will check to see if any of the specified channels are available.</para>
  79                         <para>This application sets the following channel variables:</para>
  80                         <variablelist>
  81                                 <variable name="AVAILCHAN">
  82                                         <para>The name of the available channel, if one exists</para>
  83                                 </variable>
  84                                 <variable name="AVAILORIGCHAN">
  85                                         <para>The canonical channel name that was used to create the channel</para>
  86                                 </variable>
  87                                 <variable name="AVAILSTATUS">
  88                                         <para>The status code for the available channel</para>
  89                                 </variable>
  90                         </variablelist>
  91                 </description>
  92         </application>
  93  ***/
  94
  95 static int chanavail_exec(struct ast_channel *chan, const char *data)
  96 {
  97         int inuse=-1, option_state=0, string_compare=0, option_all_avail=0;
  98         int status;
  99         char *info, tmp[512], trychan[512], *peers, *tech, *number, *rest, *cur;
 100         struct ast_str *tmp_availchan = ast_str_alloca(2048);
 101         struct ast_str *tmp_availorig = ast_str_alloca(2048);
 102         struct ast_str *tmp_availstat = ast_str_alloca(2048);
 103         struct ast_channel *tempchan;
 104         AST_DECLARE_APP_ARGS(args,
 105                 AST_APP_ARG(reqchans);
 106                 AST_APP_ARG(options);
 107         );
 108
 109         if (ast_strlen_zero(data)) {
 110                 ast_log(LOG_WARNING, "ChanIsAvail requires an argument (DAHDI/1&DAHDI/2)\n");
 111                 return -1;
 112         }
 113
 114         info = ast_strdupa(data);
 115
 116         AST_STANDARD_APP_ARGS(args, info);
 117
 118         if (args.options) {
 119                 if (strchr(args.options, 'a')) {
 120                         option_all_avail = 1;
 121                 }
 122                 if (strchr(args.options, 's')) {
 123                         option_state = 1;
 124                 }
 125                 if (strchr(args.options, 't')) {
 126                         string_compare = 1;
 127                 }
 128         }
 129         peers = args.reqchans;
 130         if (peers) {
 131                 cur = peers;
 132                 do {
 133                         /* remember where to start next time */
 134                         rest = strchr(cur, '&');
 135                         if (rest) {
 136                                 *rest = 0;
 137                                 rest++;
 138                         }
 139                         tech = cur;
 140                         number = strchr(tech, '/');
 141                         if (!number) {
 142                                 ast_log(LOG_WARNING, "ChanIsAvail argument takes format ([technology]/[device])\n");
 143                                 return -1;
 144                         }
 145                         *number = '\0';
 146                         number++;
 147
 148                         if (string_compare) {
 149                                 /* ast_parse_device_state checks for "SIP/1234" as a channel name.
 150                                    ast_device_state will ask the SIP driver for the channel state. */
 151
 152                                 snprintf(trychan, sizeof(trychan), "%s/%s",cur,number);
 153                                 status = inuse = ast_parse_device_state(trychan);
 154                         } else if (option_state) {
 155                                 /* If the pbx says in use then don't bother trying further.
 156                                    This is to permit testing if someone's on a call, even if the
 157                                    channel can permit more calls (ie callwaiting, sip calls, etc).  */
 158
 159                                 snprintf(trychan, sizeof(trychan), "%s/%s",cur,number);
 160                                 status = inuse = ast_device_state(trychan);
 161                         }
 162                         if ((inuse <= 1) && (tempchan = ast_request(tech, chan->nativeformats, chan, number, &status))) {
 163                                         ast_str_append(&tmp_availchan, 0, "%s%s", ast_str_strlen(tmp_availchan) ? "&" : "", tempchan->name);
 164
 165                                         snprintf(tmp, sizeof(tmp), "%s/%s", tech, number);
 166                                         ast_str_append(&tmp_availorig, 0, "%s%s", ast_str_strlen(tmp_availorig) ? "&" : "", tmp);
 167
 168                                         snprintf(tmp, sizeof(tmp), "%d", status);
 169                                         ast_str_append(&tmp_availstat, 0, "%s%s", ast_str_strlen(tmp_availstat) ? "&" : "", tmp);
 170
 171                                         ast_hangup(tempchan);
 172                                         tempchan = NULL;
 173
 174                                         if (!option_all_avail) {
 175                                                 break;
 176                                         }
 177                         } else {
 178                                 snprintf(tmp, sizeof(tmp), "%d", status);
 179                                 ast_str_append(&tmp_availstat, 0, "%s%s", ast_str_strlen(tmp_availstat) ? "&" : "", tmp);
 180                         }
 181                         cur = rest;
 182                 } while (cur);
 183         }
 184
 185         pbx_builtin_setvar_helper(chan, "AVAILCHAN", ast_str_buffer(tmp_availchan));
 186         /* Store the originally used channel too */
 187         pbx_builtin_setvar_helper(chan, "AVAILORIGCHAN", ast_str_buffer(tmp_availorig));
 188         pbx_builtin_setvar_helper(chan, "AVAILSTATUS", ast_str_buffer(tmp_availstat));
 189
 190         return 0;
 191 }
 192
 193 static int unload_module(void)
 194 {
 195         return ast_unregister_application(app);
 196 }
 197
 198 static int load_module(void)
 199 {
 200         return ast_register_application_xml(app, chanavail_exec) ?
 201                 AST_MODULE_LOAD_DECLINE : AST_MODULE_LOAD_SUCCESS;
 202 }
 203
 204 AST_MODULE_INFO_STANDARD(ASTERISK_GPL_KEY, "Check channel availability");