res_agi: Evaluate dialplan functions and variables in agi exec if enabled

Agi commnad exec can now evaluate dialplan functions and
variables if variable AGIEXECFULL is set to yes. this can
be useful when executing Playback or Read from agi.

ASTERISK-30058 #close

Change-Id: I669991f540496e7bddd096fec82b52c083036832

doc/CHANGES-staging/res_agi.txt

@@ -0,0 +1,5 @@
+Subject: res_agi
+
+Agi command 'exec' can now be enabled
+to evaluate dialplan functions and variables
+by setting the variable AGIEXECFULL to yes.

res/res_agi.c

@@ -296,6 +296,9 @@
 			<replaceable>options</replaceable>.</para>
 			<para>Returns whatever the <replaceable>application</replaceable> returns, or
 			<literal>-2</literal> on failure to find <replaceable>application</replaceable>.</para>
+			<note>
+				<para>exec does not evaluate dialplan functions and variables unless it is explicitly enabled by setting the <variable>AGIEXECFULL</variable> variable to <literal>yes</literal>.</para>
+			</note>
 		</description>
 		<see-also>
 			<ref type="application">AGI</ref>
@@ -3121,6 +3124,9 @@ static int handle_exec(struct ast_channel *chan, AGI *agi, int argc, const char
 {
 	int res, workaround;
 	struct ast_app *app_to_exec;
+	const char *agi_exec_full_str;
+	int agi_exec_full;
+	struct ast_str *data_with_var = NULL;
 
 	if (argc < 2)
 		return RESULT_SHOWUSAGE;
@@ -3132,8 +3138,21 @@ static int handle_exec(struct ast_channel *chan, AGI *agi, int argc, const char
 		if (!(workaround = ast_test_flag(ast_channel_flags(chan), AST_FLAG_DISABLE_WORKAROUNDS))) {
 			ast_set_flag(ast_channel_flags(chan), AST_FLAG_DISABLE_WORKAROUNDS);
 		}
+		agi_exec_full_str = pbx_builtin_getvar_helper(chan, "AGIEXECFULL");
+		agi_exec_full = ast_true(agi_exec_full_str);
 		ast_channel_unlock(chan);
-		res = pbx_exec(chan, app_to_exec, argc == 2 ? "" : argv[2]);
+
+		if (agi_exec_full) {
+			if ((data_with_var = ast_str_create(16))) {
+				ast_str_substitute_variables(&data_with_var, 0, chan, argv[2]);
+				res = pbx_exec(chan, app_to_exec, argc == 2 ? "" : ast_str_buffer(data_with_var));
+				ast_free(data_with_var);
+			} else {
+				res = -2;
+			}
+		} else {
+			res = pbx_exec(chan, app_to_exec, argc == 2 ? "" : argv[2]);
+		}
 		if (!workaround) {
 			ast_channel_clear_flag(chan, AST_FLAG_DISABLE_WORKAROUNDS);
 		}