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 /*** MODULEINFO
  31         <support_level>extended</support_level>
  32  ***/
  33
  34 #include "asterisk.h"
  35
  36 ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
  37
  38 #include <sys/ioctl.h>
  39
  40 #include "asterisk/lock.h"
  41 #include "asterisk/file.h"
  42 #include "asterisk/channel.h"
  43 #include "asterisk/pbx.h"
  44 #include "asterisk/module.h"
  45 #include "asterisk/app.h"
  46 #include "asterisk/devicestate.h"
  47
  48 static const char app[] = "ChanIsAvail";
  49
  50 /*** DOCUMENTATION
  51         <application name="ChanIsAvail" language="en_US">
  52                 <synopsis>
  53                         Check channel availability
  54                 </synopsis>
  55                 <syntax>
  56                         <parameter name="Technology/Resource" required="true" argsep="&amp;">
  57                                 <argument name="Technology2/Resource2" multiple="true">
  58                                         <para>Optional extra devices to check</para>
  59                                         <para>If you need more then one enter them as
  60                                         Technology2/Resource2&amp;Technology3/Resourse3&amp;.....</para>
  61                                 </argument>
  62                                 <para>Specification of the device(s) to check.  These must be in the format of
  63                                 <literal>Technology/Resource</literal>, where <replaceable>Technology</replaceable>
  64                                 represents a particular channel driver, and <replaceable>Resource</replaceable>
  65                                 represents a resource available to that particular channel driver.</para>
  66                         </parameter>
  67                         <parameter name="options" required="false">
  68                                 <optionlist>
  69                                         <option name="a">
  70                                                 <para>Check for all available channels, not only the first one</para>
  71                                         </option>
  72                                         <option name="s">
  73                                                 <para>Consider the channel unavailable if the channel is in use at all</para>
  74                                         </option>
  75                                         <option name="t" implies="s">
  76                                                 <para>Simply checks if specified channels exist in the channel list</para>
  77                                         </option>
  78                                 </optionlist>
  79                         </parameter>
  80                 </syntax>
  81                 <description>
  82                         <para>This application will check to see if any of the specified channels are available.</para>
  83                         <para>This application sets the following channel variables:</para>
  84                         <variablelist>
  85                                 <variable name="AVAILCHAN">
  86                                         <para>The name of the available channel, if one exists</para>
  87                                 </variable>
  88                                 <variable name="AVAILORIGCHAN">
  89                                         <para>The canonical channel name that was used to create the channel</para>
  90                                 </variable>
  91                                 <variable name="AVAILSTATUS">
  92                                         <para>The device state for the device</para>
  93                                 </variable>
  94                                 <variable name="AVAILCAUSECODE">
  95                                         <para>The cause code returned when requesting the channel</para>
  96                                 </variable>
  97                         </variablelist>
  98                 </description>
  99         </application>
 100  ***/
 101
 102 static int chanavail_exec(struct ast_channel *chan, const char *data)
 103 {
 104         int inuse=-1, option_state=0, string_compare=0, option_all_avail=0;
 105         int status;
 106         char *info, tmp[512], trychan[512], *peers, *tech, *number, *rest, *cur;
 107         struct ast_str *tmp_availchan = ast_str_alloca(2048);
 108         struct ast_str *tmp_availorig = ast_str_alloca(2048);
 109         struct ast_str *tmp_availstat = ast_str_alloca(2048);
 110         struct ast_str *tmp_availcause = ast_str_alloca(2048);
 111         struct ast_channel *tempchan;
 112         AST_DECLARE_APP_ARGS(args,
 113                 AST_APP_ARG(reqchans);
 114                 AST_APP_ARG(options);
 115         );
 116
 117         if (ast_strlen_zero(data)) {
 118                 ast_log(LOG_WARNING, "ChanIsAvail requires an argument (DAHDI/1&DAHDI/2)\n");
 119                 return -1;
 120         }
 121
 122         info = ast_strdupa(data);
 123
 124         AST_STANDARD_APP_ARGS(args, info);
 125
 126         if (args.options) {
 127                 if (strchr(args.options, 'a')) {
 128                         option_all_avail = 1;
 129                 }
 130                 if (strchr(args.options, 's')) {
 131                         option_state = 1;
 132                 }
 133                 if (strchr(args.options, 't')) {
 134                         string_compare = 1;
 135                 }
 136         }
 137         peers = args.reqchans;
 138         if (peers) {
 139                 cur = peers;
 140                 do {
 141                         /* remember where to start next time */
 142                         rest = strchr(cur, '&');
 143                         if (rest) {
 144                                 *rest = 0;
 145                                 rest++;
 146                         }
 147                         tech = cur;
 148                         number = strchr(tech, '/');
 149                         if (!number) {
 150                                 ast_log(LOG_WARNING, "ChanIsAvail argument takes format ([technology]/[device])\n");
 151                                 return -1;
 152                         }
 153                         *number = '\0';
 154                         number++;
 155
 156                         status = AST_DEVICE_UNKNOWN;
 157
 158                         if (string_compare) {
 159                                 /* ast_parse_device_state checks for "SIP/1234" as a channel name.
 160                                    ast_device_state will ask the SIP driver for the channel state. */
 161
 162                                 snprintf(trychan, sizeof(trychan), "%s/%s",cur,number);
 163                                 status = inuse = ast_parse_device_state(trychan);
 164                         } else if (option_state) {
 165                                 /* If the pbx says in use then don't bother trying further.
 166                                    This is to permit testing if someone's on a call, even if the
 167                                    channel can permit more calls (ie callwaiting, sip calls, etc).  */
 168
 169                                 snprintf(trychan, sizeof(trychan), "%s/%s",cur,number);
 170                                 status = inuse = ast_device_state(trychan);
 171                         }
 172                         snprintf(tmp, sizeof(tmp), "%d", status);
 173                         ast_str_append(&tmp_availstat, 0, "%s%s", ast_str_strlen(tmp_availstat) ? "&" : "", tmp);
 174                         if ((inuse <= 1) && (tempchan = ast_request(tech, ast_channel_nativeformats(chan), chan, number, &status))) {
 175                                         ast_str_append(&tmp_availchan, 0, "%s%s", ast_str_strlen(tmp_availchan) ? "&" : "", ast_channel_name(tempchan));
 176
 177                                         snprintf(tmp, sizeof(tmp), "%s/%s", tech, number);
 178                                         ast_str_append(&tmp_availorig, 0, "%s%s", ast_str_strlen(tmp_availorig) ? "&" : "", tmp);
 179
 180                                         snprintf(tmp, sizeof(tmp), "%d", status);
 181                                         ast_str_append(&tmp_availcause, 0, "%s%s", ast_str_strlen(tmp_availcause) ? "&" : "", tmp);
 182
 183                                         ast_hangup(tempchan);
 184                                         tempchan = NULL;
 185
 186                                         if (!option_all_avail) {
 187                                                 break;
 188                                         }
 189                         }
 190                         cur = rest;
 191                 } while (cur);
 192         }
 193
 194         pbx_builtin_setvar_helper(chan, "AVAILCHAN", ast_str_buffer(tmp_availchan));
 195         /* Store the originally used channel too */
 196         pbx_builtin_setvar_helper(chan, "AVAILORIGCHAN", ast_str_buffer(tmp_availorig));
 197         pbx_builtin_setvar_helper(chan, "AVAILSTATUS", ast_str_buffer(tmp_availstat));
 198         pbx_builtin_setvar_helper(chan, "AVAILCAUSECODE", ast_str_buffer(tmp_availcause));
 199
 200         return 0;
 201 }
 202
 203 static int unload_module(void)
 204 {
 205         return ast_unregister_application(app);
 206 }
 207
 208 static int load_module(void)
 209 {
 210         return ast_register_application_xml(app, chanavail_exec) ?
 211                 AST_MODULE_LOAD_DECLINE : AST_MODULE_LOAD_SUCCESS;
 212 }
 213
 214 AST_MODULE_INFO_STANDARD(ASTERISK_GPL_KEY, "Check channel availability");