Using the Set dialplan application does not actually
delete channel or global variables. Instead the
variables are set to an empty value.
This change adds two dialplan functions,
GLOBAL_DELETE and DELETE which can be used to
delete global and channel variables instead
of just setting them to empty.
There is also no ability within the dialplan to
determine if a global or channel variable has
actually been set or not.
This change also adds two dialplan functions,
GLOBAL_EXISTS and VARIABLE_EXISTS which can be
used to determine if a global or channel variable
has been set or not.
Resolves: #289
UserNote: Four new dialplan functions have been added.
GLOBAL_DELETE and DELETE have been added which allows
the deletion of global and channel variables.
GLOBAL_EXISTS and VARIABLE_EXISTS have been added
which checks whether a global or channel variable has
been set.
(cherry picked from commit abe4f62554
)
403 lines
10 KiB
C
403 lines
10 KiB
C
/*
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* Asterisk -- An open source telephony toolkit.
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*
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* Copyright (C) 1999 - 2006, Digium, Inc.
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* Portions Copyright (C) 2005, Anthony Minessale II
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*
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* See http://www.asterisk.org for more information about
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* the Asterisk project. Please do not directly contact
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* any of the maintainers of this project for assistance;
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* the project provides a web site, mailing lists and IRC
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* channels for your use.
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*
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* This program is free software, distributed under the terms of
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* the GNU General Public License Version 2. See the LICENSE file
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* at the top of the source tree.
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*/
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/*! \file
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*
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* \brief Conditional logic dialplan functions
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*
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* \author Anthony Minessale II
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*
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* \ingroup functions
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*/
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/*** MODULEINFO
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<support_level>core</support_level>
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***/
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#include "asterisk.h"
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#include "asterisk/module.h"
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#include "asterisk/channel.h"
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#include "asterisk/pbx.h"
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#include "asterisk/utils.h"
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#include "asterisk/app.h"
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/*** DOCUMENTATION
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<function name="ISNULL" language="en_US">
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<synopsis>
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Check if a value is NULL.
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</synopsis>
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<syntax>
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<parameter name="data" required="true" />
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</syntax>
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<description>
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<para>Returns <literal>1</literal> if NULL or <literal>0</literal> otherwise.</para>
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</description>
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</function>
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<function name="SET" language="en_US">
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<synopsis>
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SET assigns a value to a channel variable.
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</synopsis>
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<syntax argsep="=">
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<parameter name="varname" required="true" />
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<parameter name="value" />
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</syntax>
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<description>
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</description>
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</function>
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<function name="EXISTS" language="en_US">
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<synopsis>
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Test the existence of a value.
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</synopsis>
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<syntax>
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<parameter name="data" required="true" />
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</syntax>
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<description>
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<para>Returns <literal>1</literal> if exists, <literal>0</literal> otherwise.</para>
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</description>
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</function>
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<function name="IF" language="en_US">
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<synopsis>
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Check for an expression.
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</synopsis>
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<syntax argsep="?">
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<parameter name="expression" required="true" />
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<parameter name="retvalue" argsep=":" required="true">
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<argument name="true" />
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<argument name="false" />
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</parameter>
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</syntax>
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<description>
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<para>Returns the data following <literal>?</literal> if true, else the data following <literal>:</literal></para>
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</description>
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</function>
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<function name="IFTIME" language="en_US">
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<synopsis>
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Temporal Conditional.
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</synopsis>
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<syntax argsep="?">
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<parameter name="timespec" required="true" />
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<parameter name="retvalue" required="true" argsep=":">
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<argument name="true" />
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<argument name="false" />
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</parameter>
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</syntax>
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<description>
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<para>Returns the data following <literal>?</literal> if true, else the data following <literal>:</literal></para>
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</description>
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</function>
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<function name="IMPORT" language="en_US">
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<synopsis>
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Retrieve the value of a variable from another channel.
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</synopsis>
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<syntax>
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<parameter name="channel" required="true" />
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<parameter name="variable" required="true" />
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</syntax>
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<description>
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</description>
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</function>
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<function name="DELETE" language="en_US">
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<synopsis>
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Deletes a specified channel variable.
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</synopsis>
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<syntax>
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<parameter name="varname" required="true">
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<para>Channel variable name</para>
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</parameter>
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</syntax>
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<description>
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<para>Delete the channel variable specified in <replaceable>varname</replaceable>.
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Will succeed if the channel variable exists or not.</para>
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</description>
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<see-also>
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<ref type="function">GLOBAL_DELETE</ref>
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</see-also>
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</function>
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<function name="VARIABLE_EXISTS" language="en_US">
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<synopsis>
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Check if a dialplan variable exists or not.
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</synopsis>
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<syntax>
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<parameter name="varname" required="true">
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<para>Channel variable name</para>
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</parameter>
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</syntax>
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<description>
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<para>Returns <literal>1</literal> if channel variable exists or <literal>0</literal> otherwise.</para>
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</description>
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<see-also>
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<ref type="function">GLOBAL_EXISTS</ref>
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</see-also>
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</function>
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***/
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static int isnull(struct ast_channel *chan, const char *cmd, char *data,
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char *buf, size_t len)
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{
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strcpy(buf, data && *data ? "0" : "1");
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return 0;
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}
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static int exists(struct ast_channel *chan, const char *cmd, char *data, char *buf,
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size_t len)
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{
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strcpy(buf, data && *data ? "1" : "0");
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return 0;
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}
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static int iftime(struct ast_channel *chan, const char *cmd, char *data, char *buf,
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size_t len)
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{
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struct ast_timing timing;
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char *expr;
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char *iftrue;
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char *iffalse;
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data = ast_strip_quoted(data, "\"", "\"");
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expr = strsep(&data, "?");
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iftrue = strsep(&data, ":");
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iffalse = data;
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if (ast_strlen_zero(expr) || !(iftrue || iffalse)) {
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ast_log(LOG_WARNING,
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"Syntax IFTIME(<timespec>?[<true>][:<false>])\n");
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return -1;
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}
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if (!ast_build_timing(&timing, expr)) {
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ast_log(LOG_WARNING, "Invalid Time Spec.\n");
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ast_destroy_timing(&timing);
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return -1;
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}
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if (iftrue)
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iftrue = ast_strip_quoted(iftrue, "\"", "\"");
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if (iffalse)
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iffalse = ast_strip_quoted(iffalse, "\"", "\"");
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ast_copy_string(buf, ast_check_timing(&timing) ? S_OR(iftrue, "") : S_OR(iffalse, ""), len);
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ast_destroy_timing(&timing);
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return 0;
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}
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static int acf_if(struct ast_channel *chan, const char *cmd, char *data, char *buf,
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size_t len)
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{
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AST_DECLARE_APP_ARGS(args1,
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AST_APP_ARG(expr);
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AST_APP_ARG(remainder);
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);
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AST_DECLARE_APP_ARGS(args2,
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AST_APP_ARG(iftrue);
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AST_APP_ARG(iffalse);
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);
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args2.iftrue = args2.iffalse = NULL; /* you have to set these, because if there is nothing after the '?',
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then args1.remainder will be NULL, not a pointer to a null string, and
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then any garbage in args2.iffalse will not be cleared, and you'll crash.
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-- and if you mod the ast_app_separate_args func instead, you'll really
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mess things up badly, because the rest of everything depends on null args
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for non-specified stuff. */
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AST_NONSTANDARD_APP_ARGS(args1, data, '?');
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AST_NONSTANDARD_APP_ARGS(args2, args1.remainder, ':');
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if (ast_strlen_zero(args1.expr) || !(args2.iftrue || args2.iffalse)) {
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ast_debug(1, "<expr>='%s', <true>='%s', and <false>='%s'\n", args1.expr, args2.iftrue, args2.iffalse);
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return -1;
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}
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args1.expr = ast_strip(args1.expr);
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if (args2.iftrue)
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args2.iftrue = ast_strip(args2.iftrue);
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if (args2.iffalse)
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args2.iffalse = ast_strip(args2.iffalse);
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ast_copy_string(buf, pbx_checkcondition(args1.expr) ? (S_OR(args2.iftrue, "")) : (S_OR(args2.iffalse, "")), len);
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return 0;
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}
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static int set(struct ast_channel *chan, const char *cmd, char *data, char *buf,
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size_t len)
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{
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char *varname;
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char *val;
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varname = strsep(&data, "=");
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val = data;
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if (ast_strlen_zero(varname) || !val) {
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ast_log(LOG_WARNING, "Syntax SET(<varname>=[<value>])\n");
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return -1;
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}
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varname = ast_strip(varname);
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val = ast_strip(val);
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pbx_builtin_setvar_helper(chan, varname, val);
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ast_copy_string(buf, val, len);
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return 0;
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}
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static int set2(struct ast_channel *chan, const char *cmd, char *data, struct ast_str **str, ssize_t len)
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{
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if (len > -1) {
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ast_str_make_space(str, len == 0 ? strlen(data) : len);
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}
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return set(chan, cmd, data, ast_str_buffer(*str), ast_str_size(*str));
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}
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static int import_helper(struct ast_channel *chan, const char *cmd, char *data, char *buf, struct ast_str **str, ssize_t len)
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{
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AST_DECLARE_APP_ARGS(args,
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AST_APP_ARG(channel);
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AST_APP_ARG(varname);
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);
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AST_STANDARD_APP_ARGS(args, data);
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if (buf) {
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*buf = '\0';
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}
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if (!ast_strlen_zero(args.varname)) {
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struct ast_channel *chan2;
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if ((chan2 = ast_channel_get_by_name(args.channel))) {
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char *s = ast_alloca(strlen(args.varname) + 4);
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sprintf(s, "${%s}", args.varname);
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ast_channel_lock(chan2);
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if (buf) {
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pbx_substitute_variables_helper(chan2, s, buf, len);
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} else {
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ast_str_substitute_variables(str, len, chan2, s);
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}
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ast_channel_unlock(chan2);
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chan2 = ast_channel_unref(chan2);
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}
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}
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return 0;
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}
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static int import_read(struct ast_channel *chan, const char *cmd, char *data, char *buf, size_t len)
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{
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return import_helper(chan, cmd, data, buf, NULL, len);
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}
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static int import_read2(struct ast_channel *chan, const char *cmd, char *data, struct ast_str **str, ssize_t len)
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{
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return import_helper(chan, cmd, data, NULL, str, len);
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}
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static int delete_write(struct ast_channel *chan, const char *cmd, char *data, const char *value)
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{
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pbx_builtin_setvar_helper(chan, data, NULL);
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return 0;
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}
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static int variable_exists_read(struct ast_channel *chan, const char *cmd, char *data,
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char *buf, size_t len)
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{
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const char *var = pbx_builtin_getvar_helper(chan, data);
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strcpy(buf, var ? "1" : "0");
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return 0;
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}
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static struct ast_custom_function isnull_function = {
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.name = "ISNULL",
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.read = isnull,
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.read_max = 2,
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};
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static struct ast_custom_function set_function = {
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.name = "SET",
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.read = set,
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.read2 = set2,
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};
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static struct ast_custom_function exists_function = {
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.name = "EXISTS",
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.read = exists,
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.read_max = 2,
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};
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static struct ast_custom_function if_function = {
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.name = "IF",
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.read = acf_if,
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};
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static struct ast_custom_function if_time_function = {
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.name = "IFTIME",
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.read = iftime,
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};
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static struct ast_custom_function import_function = {
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.name = "IMPORT",
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.read = import_read,
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.read2 = import_read2,
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};
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static struct ast_custom_function delete_function = {
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.name = "DELETE",
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.write = delete_write,
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};
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static struct ast_custom_function variable_exists_function = {
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.name = "VARIABLE_EXISTS",
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.read = variable_exists_read,
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};
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static int unload_module(void)
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{
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int res = 0;
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res |= ast_custom_function_unregister(&isnull_function);
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res |= ast_custom_function_unregister(&set_function);
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res |= ast_custom_function_unregister(&exists_function);
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res |= ast_custom_function_unregister(&if_function);
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res |= ast_custom_function_unregister(&if_time_function);
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res |= ast_custom_function_unregister(&import_function);
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res |= ast_custom_function_unregister(&delete_function);
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res |= ast_custom_function_unregister(&variable_exists_function);
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return res;
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}
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static int load_module(void)
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{
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int res = 0;
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res |= ast_custom_function_register(&isnull_function);
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res |= ast_custom_function_register(&set_function);
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res |= ast_custom_function_register(&exists_function);
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res |= ast_custom_function_register(&if_function);
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res |= ast_custom_function_register(&if_time_function);
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res |= ast_custom_function_register(&import_function);
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res |= ast_custom_function_register(&delete_function);
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res |= ast_custom_function_register(&variable_exists_function);
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return res;
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}
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AST_MODULE_INFO_STANDARD(ASTERISK_GPL_KEY, "Logical dialplan functions");
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