asterisk/apps/app_system.c

195 lines
5.3 KiB
C

/*
* Asterisk -- An open source telephony toolkit.
*
* Copyright (C) 1999 - 2005, Digium, Inc.
*
* Mark Spencer <markster@digium.com>
*
* See http://www.asterisk.org for more information about
* the Asterisk project. Please do not directly contact
* any of the maintainers of this project for assistance;
* the project provides a web site, mailing lists and IRC
* channels for your use.
*
* This program is free software, distributed under the terms of
* the GNU General Public License Version 2. See the LICENSE file
* at the top of the source tree.
*/
/*! \file
*
* \brief Execute arbitrary system commands
*
* \author Mark Spencer <markster@digium.com>
*
* \ingroup applications
*/
/*** MODULEINFO
<support_level>core</support_level>
***/
#include "asterisk.h"
#include "asterisk/pbx.h"
#include "asterisk/module.h"
#include "asterisk/app.h"
#include "asterisk/channel.h" /* autoservice */
#include "asterisk/strings.h"
#include "asterisk/threadstorage.h"
/*** DOCUMENTATION
<application name="System" language="en_US">
<synopsis>
Execute a system command.
</synopsis>
<syntax>
<parameter name="command" required="true">
<para>Command to execute</para>
<warning><para>Do not use untrusted strings such as <variable>CALLERID(num)</variable>
or <variable>CALLERID(name)</variable> as part of the command parameters. You
risk a command injection attack executing arbitrary commands if the untrusted
strings aren't filtered to remove dangerous characters. See function
<variable>FILTER()</variable>.</para></warning>
</parameter>
</syntax>
<description>
<para>Executes a command by using system(). If the command
fails, the console should report a fallthrough.</para>
<para>Result of execution is returned in the <variable>SYSTEMSTATUS</variable> channel variable:</para>
<variablelist>
<variable name="SYSTEMSTATUS">
<value name="FAILURE">
Could not execute the specified command.
</value>
<value name="SUCCESS">
Specified command successfully executed.
</value>
</variable>
</variablelist>
</description>
</application>
<application name="TrySystem" language="en_US">
<synopsis>
Try executing a system command.
</synopsis>
<syntax>
<parameter name="command" required="true">
<para>Command to execute</para>
<warning><para>Do not use untrusted strings such as <variable>CALLERID(num)</variable>
or <variable>CALLERID(name)</variable> as part of the command parameters. You
risk a command injection attack executing arbitrary commands if the untrusted
strings aren't filtered to remove dangerous characters. See function
<variable>FILTER()</variable>.</para></warning>
</parameter>
</syntax>
<description>
<para>Executes a command by using system().</para>
<para>Result of execution is returned in the <variable>SYSTEMSTATUS</variable> channel variable:</para>
<variablelist>
<variable name="SYSTEMSTATUS">
<value name="FAILURE">
Could not execute the specified command.
</value>
<value name="SUCCESS">
Specified command successfully executed.
</value>
<value name="APPERROR">
Specified command successfully executed, but returned error code.
</value>
</variable>
</variablelist>
</description>
</application>
***/
AST_THREADSTORAGE(buf_buf);
static char *app = "System";
static char *app2 = "TrySystem";
static char *chanvar = "SYSTEMSTATUS";
static int system_exec_helper(struct ast_channel *chan, const char *data, int failmode)
{
int res = 0;
struct ast_str *buf = ast_str_thread_get(&buf_buf, 16);
char *cbuf;
if (ast_strlen_zero(data)) {
ast_log(LOG_WARNING, "System requires an argument(command)\n");
pbx_builtin_setvar_helper(chan, chanvar, "FAILURE");
return failmode;
}
ast_autoservice_start(chan);
/* Do our thing here */
ast_str_get_encoded_str(&buf, 0, (char *) data);
cbuf = ast_str_buffer(buf);
if (strchr("\"'", cbuf[0]) && cbuf[ast_str_strlen(buf) - 1] == cbuf[0]) {
cbuf[ast_str_strlen(buf) - 1] = '\0';
cbuf++;
ast_log(LOG_NOTICE, "It is not necessary to quote the argument to the System application.\n");
}
res = ast_safe_system(cbuf);
if ((res < 0) && (errno != ECHILD)) {
ast_log(LOG_WARNING, "Unable to execute '%s'\n", (char *)data);
pbx_builtin_setvar_helper(chan, chanvar, "FAILURE");
res = failmode;
} else if (res == 127) {
ast_log(LOG_WARNING, "Unable to execute '%s'\n", (char *)data);
pbx_builtin_setvar_helper(chan, chanvar, "FAILURE");
res = failmode;
} else {
if (res < 0)
res = 0;
if (res != 0)
pbx_builtin_setvar_helper(chan, chanvar, "APPERROR");
else
pbx_builtin_setvar_helper(chan, chanvar, "SUCCESS");
res = 0;
}
ast_autoservice_stop(chan);
return res;
}
static int system_exec(struct ast_channel *chan, const char *data)
{
return system_exec_helper(chan, data, -1);
}
static int trysystem_exec(struct ast_channel *chan, const char *data)
{
return system_exec_helper(chan, data, 0);
}
static int unload_module(void)
{
int res;
res = ast_unregister_application(app);
res |= ast_unregister_application(app2);
return res;
}
static int load_module(void)
{
int res;
res = ast_register_application_xml(app2, trysystem_exec);
res |= ast_register_application_xml(app, system_exec);
return res;
}
AST_MODULE_INFO_STANDARD(ASTERISK_GPL_KEY, "Generic System() application");