Wed Jan 8 2020 09:49:39

Asterisk developer's documentation


app_chanisavail.c
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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: 359486 $")
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;
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 
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, chan->nativeformats, chan, number, &status))) {
175  ast_str_append(&tmp_availchan, 0, "%s%s", ast_str_strlen(tmp_availchan) ? "&" : "", tempchan->name);
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 {
212 }
213 
214 AST_MODULE_INFO_STANDARD(ASTERISK_GPL_KEY, "Check channel availability");
static const char app[]
int ast_hangup(struct ast_channel *chan)
Hang up a channel.
Definition: channel.c:2804
Main Channel structure associated with a channel.
Definition: channel.h:742
ast_device_state
Device States.
Definition: devicestate.h:51
#define AST_MODULE_INFO_STANDARD(keystr, desc)
Definition: module.h:396
Asterisk locking-related definitions:
Asterisk main include file. File version handling, generic pbx functions.
Device state management.
#define LOG_WARNING
Definition: logger.h:144
char * ast_str_buffer(const struct ast_str *buf)
Returns the string buffer within the ast_str buf.
Definition: strings.h:497
static int unload_module(void)
#define AST_DECLARE_APP_ARGS(name, arglist)
Declare a structure to hold an application&#39;s arguments.
Definition: app.h:572
enum ast_device_state ast_parse_device_state(const char *device)
Search the Channels by Name.
Definition: devicestate.c:271
int ast_str_append(struct ast_str **buf, ssize_t max_len, const char *fmt,...)
Append to a thread local dynamic string.
Definition: strings.h:900
format_t nativeformats
Definition: channel.h:852
#define ast_str_alloca(init_len)
Definition: strings.h:608
Generic File Format Support. Should be included by clients of the file handling routines. File service providers should instead include mod_format.h.
static int load_module(void)
int ast_unregister_application(const char *app)
Unregister an application.
Definition: pbx.c:7705
Number structure.
Definition: app_followme.c:109
General Asterisk PBX channel definitions.
static struct ao2_container * peers
Definition: chan_iax2.c:885
static int chanavail_exec(struct ast_channel *chan, const char *data)
static force_inline int attribute_pure ast_strlen_zero(const char *s)
Definition: strings.h:63
Core PBX routines and definitions.
#define ast_strdupa(s)
duplicate a string in memory from the stack
Definition: utils.h:663
The descriptor of a dynamic string XXX storage will be optimized later if needed We use the ts field ...
Definition: strings.h:364
static struct @350 args
const ast_string_field name
Definition: channel.h:787
void ast_log(int level, const char *file, int line, const char *function, const char *fmt,...)
Used for sending a log message This is the standard logger function. Probably the only way you will i...
Definition: logger.c:1207
int pbx_builtin_setvar_helper(struct ast_channel *chan, const char *name, const char *value)
Add a variable to the channel variable stack, removing the most recently set value for the same name...
Definition: pbx.c:10546
size_t ast_str_strlen(const struct ast_str *buf)
Returns the current length of the string stored within buf.
Definition: strings.h:471
Application convenience functions, designed to give consistent look and feel to Asterisk apps...
#define AST_APP_ARG(name)
Define an application argument.
Definition: app.h:555
#define AST_STANDARD_APP_ARGS(args, parse)
Performs the &#39;standard&#39; argument separation process for an application.
Definition: app.h:604
#define ASTERISK_GPL_KEY
The text the key() function should return.
Definition: module.h:38
Asterisk module definitions.
struct ast_channel * ast_request(const char *type, format_t format, const struct ast_channel *requestor, void *data, int *status)
Requests a channel.
Definition: channel.c:5695
#define ast_register_application_xml(app, execute)
Register an application using XML documentation.
Definition: module.h:437
jack_status_t status
Definition: app_jack.c:143
#define ASTERISK_FILE_VERSION(file, version)
Register/unregister a source code file with the core.
Definition: asterisk.h:180