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 #include <sys/ioctl.h>
  37
  38 #include "asterisk/lock.h"
  39 #include "asterisk/file.h"
  40 #include "asterisk/channel.h"
  41 #include "asterisk/pbx.h"
  42 #include "asterisk/module.h"
  43 #include "asterisk/app.h"
  44 #include "asterisk/devicestate.h"
  45
  46 static const char app[] = "ChanIsAvail";
  47
  48 /*** DOCUMENTATION
  49         <application name="ChanIsAvail" language="en_US">
  50                 <synopsis>
  51                         Check channel availability
  52                 </synopsis>
  53                 <syntax>
  54                         <parameter name="Technology/Resource" required="true" argsep="&amp;">
  55                                 <argument name="Technology2/Resource2" multiple="true">
  56                                         <para>Optional extra devices to check</para>
  57                                         <para>If you need more than one enter them as
  58                                         Technology2/Resource2&amp;Technology3/Resource3&amp;.....</para>
  59                                 </argument>
  60                                 <para>Specification of the device(s) to check.  These must be in the format of
  61                                 <literal>Technology/Resource</literal>, where <replaceable>Technology</replaceable>
  62                                 represents a particular channel driver, and <replaceable>Resource</replaceable>
  63                                 represents a resource available to that particular channel driver.</para>
  64                         </parameter>
  65                         <parameter name="options" required="false">
  66                                 <optionlist>
  67                                         <option name="a">
  68                                                 <para>Check for all available channels, not only the first one</para>
  69                                         </option>
  70                                         <option name="s">
  71                                                 <para>Consider the channel unavailable if the channel is in use at all</para>
  72                                         </option>
  73                                         <option name="t" implies="s">
  74                                                 <para>Simply checks if specified channels exist in the channel list</para>
  75                                         </option>
  76                                 </optionlist>
  77                         </parameter>
  78                 </syntax>
  79                 <description>
  80                         <para>This application will check to see if any of the specified channels are available.</para>
  81                         <para>This application sets the following channel variables:</para>
  82                         <variablelist>
  83                                 <variable name="AVAILCHAN">
  84                                         <para>The name of the available channel, if one exists</para>
  85                                 </variable>
  86                                 <variable name="AVAILORIGCHAN">
  87                                         <para>The canonical channel name that was used to create the channel</para>
  88                                 </variable>
  89                                 <variable name="AVAILSTATUS">
  90                                         <para>The device state for the device</para>
  91                                 </variable>
  92                                 <variable name="AVAILCAUSECODE">
  93                                         <para>The cause code returned when requesting the channel</para>
  94                                 </variable>
  95                         </variablelist>
  96                 </description>
  97         </application>
  98  ***/
  99
 100 static int chanavail_exec(struct ast_channel *chan, const char *data)
 101 {
 102         int inuse=-1, option_state=0, string_compare=0, option_all_avail=0;
 103         int status;
 104         char *info, tmp[512], trychan[512], *peers, *tech, *number, *rest, *cur;
 105         struct ast_str *tmp_availchan = ast_str_alloca(2048);
 106         struct ast_str *tmp_availorig = ast_str_alloca(2048);
 107         struct ast_str *tmp_availstat = ast_str_alloca(2048);
 108         struct ast_str *tmp_availcause = ast_str_alloca(2048);
 109         struct ast_channel *tempchan;
 110         AST_DECLARE_APP_ARGS(args,
 111                 AST_APP_ARG(reqchans);
 112                 AST_APP_ARG(options);
 113         );
 114
 115         if (ast_strlen_zero(data)) {
 116                 ast_log(LOG_WARNING, "ChanIsAvail requires an argument (DAHDI/1&DAHDI/2)\n");
 117                 return -1;
 118         }
 119
 120         info = ast_strdupa(data);
 121
 122         AST_STANDARD_APP_ARGS(args, info);
 123
 124         if (args.options) {
 125                 if (strchr(args.options, 'a')) {
 126                         option_all_avail = 1;
 127                 }
 128                 if (strchr(args.options, 's')) {
 129                         option_state = 1;
 130                 }
 131                 if (strchr(args.options, 't')) {
 132                         string_compare = 1;
 133                 }
 134         }
 135         peers = args.reqchans;
 136         if (peers) {
 137                 cur = peers;
 138                 do {
 139                         /* remember where to start next time */
 140                         rest = strchr(cur, '&');
 141                         if (rest) {
 142                                 *rest = 0;
 143                                 rest++;
 144                         }
 145                         tech = cur;
 146                         number = strchr(tech, '/');
 147                         if (!number) {
 148                                 ast_log(LOG_WARNING, "ChanIsAvail argument takes format ([technology]/[device])\n");
 149                                 return -1;
 150                         }
 151                         *number = '\0';
 152                         number++;
 153
 154                         status = AST_DEVICE_UNKNOWN;
 155
 156                         if (string_compare) {
 157                                 /* ast_parse_device_state checks for "SIP/1234" as a channel name.
 158                                    ast_device_state will ask the SIP driver for the channel state. */
 159
 160                                 snprintf(trychan, sizeof(trychan), "%s/%s",cur,number);
 161                                 status = inuse = ast_parse_device_state(trychan);
 162                         } else if (option_state) {
 163                                 /* If the pbx says in use then don't bother trying further.
 164                                    This is to permit testing if someone's on a call, even if the
 165                                    channel can permit more calls (ie callwaiting, sip calls, etc).  */
 166
 167                                 snprintf(trychan, sizeof(trychan), "%s/%s",cur,number);
 168                                 status = inuse = ast_device_state(trychan);
 169                         }
 170                         snprintf(tmp, sizeof(tmp), "%d", status);
 171                         ast_str_append(&tmp_availstat, 0, "%s%s", ast_str_strlen(tmp_availstat) ? "&" : "", tmp);
 172                         if ((inuse <= 1) && (tempchan = ast_request(tech, ast_channel_nativeformats(chan), NULL, chan, number, &status))) {
 173                                         ast_str_append(&tmp_availchan, 0, "%s%s", ast_str_strlen(tmp_availchan) ? "&" : "", ast_channel_name(tempchan));
 174
 175                                         snprintf(tmp, sizeof(tmp), "%s/%s", tech, number);
 176                                         ast_str_append(&tmp_availorig, 0, "%s%s", ast_str_strlen(tmp_availorig) ? "&" : "", tmp);
 177
 178                                         snprintf(tmp, sizeof(tmp), "%d", status);
 179                                         ast_str_append(&tmp_availcause, 0, "%s%s", ast_str_strlen(tmp_availcause) ? "&" : "", tmp);
 180
 181                                         ast_hangup(tempchan);
 182                                         tempchan = NULL;
 183
 184                                         if (!option_all_avail) {
 185                                                 break;
 186                                         }
 187                         }
 188                         cur = rest;
 189                 } while (cur);
 190         }
 191
 192         pbx_builtin_setvar_helper(chan, "AVAILCHAN", ast_str_buffer(tmp_availchan));
 193         /* Store the originally used channel too */
 194         pbx_builtin_setvar_helper(chan, "AVAILORIGCHAN", ast_str_buffer(tmp_availorig));
 195         pbx_builtin_setvar_helper(chan, "AVAILSTATUS", ast_str_buffer(tmp_availstat));
 196         pbx_builtin_setvar_helper(chan, "AVAILCAUSECODE", ast_str_buffer(tmp_availcause));
 197
 198         return 0;
 199 }
 200
 201 static int unload_module(void)
 202 {
 203         return ast_unregister_application(app);
 204 }
 205
 206 static int load_module(void)
 207 {
 208         return ast_register_application_xml(app, chanavail_exec) ?
 209                 AST_MODULE_LOAD_DECLINE : AST_MODULE_LOAD_SUCCESS;
 210 }
 211
 212 AST_MODULE_INFO_STANDARD_EXTENDED(ASTERISK_GPL_KEY, "Check channel availability");
 213