endless recursion loop protection to go with new recursive variable expansion feature

src/include/switch_channel.h

@@ -593,8 +593,8 @@ SWITCH_DECLARE(void) switch_channel_event_set_extended_data(_In_ switch_channel_
   \return the original string if no expansion takes place otherwise a new string that must be freed
   \note it's necessary to test if the return val is the same as the input and free the string if it is not.
 */
-SWITCH_DECLARE(char *) switch_channel_expand_variables_check(switch_channel_t *channel, const char *in, switch_event_t *var_list, switch_event_t *api_list);
-#define switch_channel_expand_variables(_channel, _in) switch_channel_expand_variables_check(_channel, _in, NULL, NULL)
+SWITCH_DECLARE(char *) switch_channel_expand_variables_check(switch_channel_t *channel, const char *in, switch_event_t *var_list, switch_event_t *api_list, uint32_t recur);
+#define switch_channel_expand_variables(_channel, _in) switch_channel_expand_variables_check(_channel, _in, NULL, NULL, 0)
 
 
 SWITCH_DECLARE(char *) switch_channel_build_param_string(_In_ switch_channel_t *channel, _In_opt_ switch_caller_profile_t *caller_profile,

src/include/switch_event.h

@@ -330,8 +330,8 @@ SWITCH_DECLARE(switch_status_t) switch_event_add_body(switch_event_t *event, con
 
 SWITCH_DECLARE(switch_status_t) switch_event_set_body(switch_event_t *event, const char *body);
 
-SWITCH_DECLARE(char *) switch_event_expand_headers_check(switch_event_t *event, const char *in, switch_event_t *var_list, switch_event_t *api_list);
-#define switch_event_expand_headers(_event, _in) switch_event_expand_headers_check(_event, _in, NULL, NULL)
+SWITCH_DECLARE(char *) switch_event_expand_headers_check(switch_event_t *event, const char *in, switch_event_t *var_list, switch_event_t *api_list, uint32_t recur);
+#define switch_event_expand_headers(_event, _in) switch_event_expand_headers_check(_event, _in, NULL, NULL, 0)
 
 SWITCH_DECLARE(switch_status_t) switch_event_create_pres_in_detailed(_In_z_ char *file, _In_z_ char *func, _In_ int line,
 																	 _In_z_ const char *proto, _In_z_ const char *login,

src/switch_channel.c

@@ -3345,7 +3345,7 @@ SWITCH_DECLARE(switch_status_t) switch_channel_perform_answer(switch_channel_t *
 	memset(c, 0, olen - cpos);\
 	}}                           \
 
-SWITCH_DECLARE(char *) switch_channel_expand_variables_check(switch_channel_t *channel, const char *in, switch_event_t *var_list, switch_event_t *api_list)
+SWITCH_DECLARE(char *) switch_channel_expand_variables_check(switch_channel_t *channel, const char *in, switch_event_t *var_list, switch_event_t *api_list, uint32_t recur)
 {
 	char *p, *c = NULL;
 	char *data, *indup, *endof_indup;
@@ -3354,6 +3354,10 @@ SWITCH_DECLARE(char *) switch_channel_expand_variables_check(switch_channel_t *c
 	char *func_val = NULL, *sb = NULL;
 	int nv = 0;
 
+	if (recur > 100) {
+		return (char *) in;
+	}
+
 	if (zstr(in)) {
 		return (char *) in;
 	}
@@ -3483,7 +3487,7 @@ SWITCH_DECLARE(char *) switch_channel_expand_variables_check(switch_channel_t *c
 					char *ptr;
 					int idx = -1;
 					
-					if ((expanded = switch_channel_expand_variables_check(channel, (char *) vname, var_list, api_list)) == vname) {
+					if ((expanded = switch_channel_expand_variables_check(channel, (char *) vname, var_list, api_list, recur+1)) == vname) {
 						expanded = NULL;
 					} else {
 						vname = expanded;
@@ -3508,7 +3512,7 @@ SWITCH_DECLARE(char *) switch_channel_expand_variables_check(switch_channel_t *c
 							sub_val = "INVALID";
 						}
 
-						if ((expanded_sub_val = switch_channel_expand_variables(channel, sub_val)) == sub_val) {
+						if ((expanded_sub_val = switch_channel_expand_variables_check(channel, sub_val, var_list, api_list, recur+1)) == sub_val) {
 							expanded_sub_val = NULL;
 						} else {
 							sub_val = expanded_sub_val;
@@ -3547,13 +3551,13 @@ SWITCH_DECLARE(char *) switch_channel_expand_variables_check(switch_channel_t *c
 					if (stream.data) {
 						char *expanded_vname = NULL;
 						
-						if ((expanded_vname = switch_channel_expand_variables_check(channel, (char *) vname, var_list, api_list)) == vname) {
+						if ((expanded_vname = switch_channel_expand_variables_check(channel, (char *) vname, var_list, api_list, recur+1)) == vname) {
 							expanded_vname = NULL;
 						} else {
 							vname = expanded_vname;
 						}
 
-						if ((expanded = switch_channel_expand_variables_check(channel, vval, var_list, api_list)) == vval) {
+						if ((expanded = switch_channel_expand_variables_check(channel, vval, var_list, api_list, recur+1)) == vval) {
 							expanded = NULL;
 						} else {
 							vval = expanded;

src/switch_event.c

@@ -1992,7 +1992,7 @@ if ((dp = realloc(data, olen))) {\
     memset(c, 0, olen - cpos);\
  }}                           \
 
-SWITCH_DECLARE(char *) switch_event_expand_headers_check(switch_event_t *event, const char *in, switch_event_t *var_list, switch_event_t *api_list)
+SWITCH_DECLARE(char *) switch_event_expand_headers_check(switch_event_t *event, const char *in, switch_event_t *var_list, switch_event_t *api_list, uint32_t recur)
 {
 	char *p, *c = NULL;
 	char *data, *indup, *endof_indup;
@@ -2003,6 +2003,10 @@ SWITCH_DECLARE(char *) switch_event_expand_headers_check(switch_event_t *event,
 	int nv = 0;
 	char *gvar = NULL, *sb = NULL;
 
+	if (recur > 100) {
+		return (char *) in;
+	}
+
 	if (zstr(in)) {
 		return (char *) in;
 	}
@@ -2132,7 +2136,7 @@ SWITCH_DECLARE(char *) switch_event_expand_headers_check(switch_event_t *event,
 					char *ptr;
 					int idx = -1;
 					
-					if ((expanded = switch_event_expand_headers_check(event, (char *) vname, var_list, api_list)) == vname) {
+					if ((expanded = switch_event_expand_headers_check(event, (char *) vname, var_list, api_list, recur+1)) == vname) {
 						expanded = NULL;
 					} else {
 						vname = expanded;
@@ -2162,7 +2166,7 @@ SWITCH_DECLARE(char *) switch_event_expand_headers_check(switch_event_t *event,
 						}
 
 
-						if ((expanded_sub_val = switch_event_expand_headers(event, sub_val)) == sub_val) {
+						if ((expanded_sub_val = switch_event_expand_headers_check(event, sub_val, var_list, api_list, recur+1)) == sub_val) {
 							expanded_sub_val = NULL;
 						} else {
 							sub_val = expanded_sub_val;
@@ -2198,13 +2202,13 @@ SWITCH_DECLARE(char *) switch_event_expand_headers_check(switch_event_t *event,
 					if (stream.data) {
 						char *expanded_vname = NULL;
 
-						if ((expanded_vname = switch_event_expand_headers_check(event, (char *) vname, var_list, api_list)) == vname) {
+						if ((expanded_vname = switch_event_expand_headers_check(event, (char *) vname, var_list, api_list, recur+1)) == vname) {
 							expanded_vname = NULL;
 						} else {
 							vname = expanded_vname;
 						}
 
-						if ((expanded = switch_event_expand_headers_check(event, vval, var_list, api_list)) == vval) {
+						if ((expanded = switch_event_expand_headers_check(event, vval, var_list, api_list, recur+1)) == vval) {
 							expanded = NULL;
 						} else {
 							vval = expanded;