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[asterisk/asterisk.git] / 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 char *app = "ChanIsAvail";
45
46 static char *synopsis = "Check channel availability";
47
48 static char *descrip =
49 "  ChanIsAvail(Technology/resource[&Technology2/resource2...][,options]): \n"
50 "This application will check to see if any of the specified channels are\n"
51 "available.\n"
52 "  Options:\n"
53 "    s - Consider the channel unavailable if the channel is in use at all.\n"
54 "    t - Simply checks if specified channels exist in the channel list\n"
55 "        (implies option s).\n"
56 "This application sets the following channel variable upon completion:\n"
57 "  AVAILCHAN     - the name of the available channel, if one exists\n"
58 "  AVAILORIGCHAN - the canonical channel name that was used to create the channel\n"
59 "  AVAILSTATUS   - the status code for the available channel\n";
60
61
62 static int chanavail_exec(struct ast_channel *chan, void *data)
63 {
64         int res=-1, inuse=-1, option_state=0, string_compare=0;
65         int status;
66         char *info, tmp[512], trychan[512], *peers, *tech, *number, *rest, *cur;
67         struct ast_channel *tempchan;
68         AST_DECLARE_APP_ARGS(args,
69                 AST_APP_ARG(reqchans);
70                 AST_APP_ARG(options);
71         );
72
73         if (ast_strlen_zero(data)) {
74                 ast_log(LOG_WARNING, "ChanIsAvail requires an argument (Zap/1&Zap/2)\n");
75                 return -1;
76         }
77
78         info = ast_strdupa(data);
79
80         AST_STANDARD_APP_ARGS(args, info);
81
82         if (args.options) {
83                 if (strchr(args.options, 's'))
84                         option_state = 1;
85                 if (strchr(args.options, 't'))
86                         string_compare = 1;
87         }
88         peers = args.reqchans;
89         if (peers) {
90                 cur = peers;
91                 do {
92                         /* remember where to start next time */
93                         rest = strchr(cur, '&');
94                         if (rest) {
95                                 *rest = 0;
96                                 rest++;
97                         }
98                         tech = cur;
99                         number = strchr(tech, '/');
100                         if (!number) {
101                                 ast_log(LOG_WARNING, "ChanIsAvail argument takes format ([technology]/[device])\n");
102                                 return -1;
103                         }
104                         *number = '\0';
105                         number++;
106                         
107                         if (string_compare) {
108                                 /* ast_parse_device_state checks for "SIP/1234" as a channel name.
109                                    ast_device_state will ask the SIP driver for the channel state. */
110
111                                 snprintf(trychan, sizeof(trychan), "%s/%s",cur,number);
112                                 status = inuse = ast_parse_device_state(trychan);
113                         } else if (option_state) {
114                                 /* If the pbx says in use then don't bother trying further.
115                                    This is to permit testing if someone's on a call, even if the
116                                    channel can permit more calls (ie callwaiting, sip calls, etc).  */
117
118                                 snprintf(trychan, sizeof(trychan), "%s/%s",cur,number);
119                                 status = inuse = ast_device_state(trychan);
120                         }
121                         if ((inuse <= 1) && (tempchan = ast_request(tech, chan->nativeformats, number, &status))) {
122                                         pbx_builtin_setvar_helper(chan, "AVAILCHAN", tempchan->name);
123                                         /* Store the originally used channel too */
124                                         snprintf(tmp, sizeof(tmp), "%s/%s", tech, number);
125                                         pbx_builtin_setvar_helper(chan, "AVAILORIGCHAN", tmp);
126                                         snprintf(tmp, sizeof(tmp), "%d", status);
127                                         pbx_builtin_setvar_helper(chan, "AVAILSTATUS", tmp);
128                                         ast_hangup(tempchan);
129                                         tempchan = NULL;
130                                         res = 1;
131                                         break;
132                         } else {
133                                 snprintf(tmp, sizeof(tmp), "%d", status);
134                                 pbx_builtin_setvar_helper(chan, "AVAILSTATUS", tmp);
135                         }
136                         cur = rest;
137                 } while (cur);
138         }
139         if (res < 1) {
140                 pbx_builtin_setvar_helper(chan, "AVAILCHAN", "");
141                 pbx_builtin_setvar_helper(chan, "AVAILORIGCHAN", "");
142         }
143
144         return 0;
145 }
146
147 static int unload_module(void)
148 {
149         return ast_unregister_application(app);
150 }
151
152 static int load_module(void)
153 {
154         return ast_register_application(app, chanavail_exec, synopsis, descrip);
155 }
156
157 AST_MODULE_INFO_STANDARD(ASTERISK_GPL_KEY, "Check channel availability");