e403efc2e82cf3a4d5d24e1b6e53869bfb9ec1e2
[asterisk/asterisk.git] / funcs / func_shell.c
1 /*
2  * Asterisk -- An open source telephony toolkit.
3  *
4  * Copyright (C) 2006-2012, Digium, Inc.
5  *
6  * See http://www.asterisk.org for more information about
7  * the Asterisk project. Please do not directly contact
8  * any of the maintainers of this project for assistance;
9  * the project provides a web site, mailing lists and IRC
10  * channels for your use.
11  *
12  * This program is free software, distributed under the terms of
13  * the GNU General Public License Version 2. See the LICENSE file
14  * at the top of the source tree.
15  */
16
17 /*! \file
18  *
19  * SHELL function to return the output generated by a command issued to the system shell.
20  *
21  * \note Inspiration and Guidance from Russell! Thank You!
22  *
23  * \author Brandon Kruse <bkruse@digium.com>
24  *
25  * \ingroup functions
26  */
27
28 /*** MODULEINFO
29         <support_level>core</support_level>
30  ***/
31
32 #include "asterisk.h"
33
34 ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
35
36 #include "asterisk/module.h"
37 #include "asterisk/channel.h"
38 #include "asterisk/pbx.h"
39 #include "asterisk/utils.h"
40 #include "asterisk/app.h"
41
42 static int shell_helper(struct ast_channel *chan, const char *cmd, char *data,
43                                          char *buf, size_t len)
44 {
45         int res = 0;
46
47         if (ast_strlen_zero(data)) {
48                 ast_log(LOG_WARNING, "Missing Argument!  Example:  Set(foo=${SHELL(echo \"bar\")})\n");
49                 return -1;
50         }
51
52         if (chan) {
53                 ast_autoservice_start(chan);
54         }
55
56         if (len >= 1) {
57                 FILE *ptr;
58                 char plbuff[4096];
59
60                 ptr = popen(data, "r");
61                 if (ptr) {
62                         while (fgets(plbuff, sizeof(plbuff), ptr)) {
63                                 strncat(buf, plbuff, len - strlen(buf) - 1);
64                         }
65                         pclose(ptr);
66                 } else {
67                         ast_log(LOG_WARNING, "Failed to execute shell command '%s'\n", data);
68                         res = -1;
69                 }
70         }
71
72         if (chan) {
73                 ast_autoservice_stop(chan);
74         }
75
76         return res;
77 }
78
79 /*** DOCUMENTATION
80         <function name="SHELL" language="en_US">
81                 <synopsis>
82                         Executes a command using the system shell and captures its output.
83                 </synopsis>
84                 <syntax>
85                         <parameter name="command" required="true">
86                                 <para>The command that the shell should execute.</para>
87                         </parameter>
88                 </syntax>
89                 <description>
90                         <para>Collects the output generated by a command executed by the system shell</para>
91                         <para>Example:  <literal>Set(foo=${SHELL(echo bar)})</literal></para>
92                         <note>
93                                 <para>The command supplied to this function will be executed by the
94                                 system's shell, typically specified in the SHELL environment variable. There
95                                 are many different system shells available with somewhat different behaviors,
96                                 so the output generated by this function may vary between platforms.</para>
97
98                                 <para>If <literal>live_dangerously</literal> in <literal>asterisk.conf</literal>
99                                 is set to <literal>no</literal>, this function can only be executed from the
100                                 dialplan, and not directly from external protocols.</para>
101                         </note>
102                 </description>
103
104         </function>
105  ***/
106 static struct ast_custom_function shell_function = {
107         .name = "SHELL",
108         .read = shell_helper,
109 };
110
111 static int unload_module(void)
112 {
113         return ast_custom_function_unregister(&shell_function);
114 }
115
116 static int load_module(void)
117 {
118         return ast_custom_function_register_escalating(&shell_function, AST_CFE_READ);
119 }
120
121 AST_MODULE_INFO_STANDARD(ASTERISK_GPL_KEY, "Collects the output generated by a command executed by the system shell");