cfgutils: Add support for large diffs in ts_usec_delta()

This patch reworks the 5th parameter as a string output variable, thus
avoiding issues related to integer overflows when the time diffs get
larger (e.g. differences of 35+ minutes, which are not uncommon).

Note: NOT backwards-compatible

modules/cfgutils/cfgutils.c

@@ -106,8 +106,8 @@ mi_response_t *mi_check_hash(const mi_params_t *params,
 static int pv_get_random_val(struct sip_msg *msg, pv_param_t *param,
 		pv_value_t *res);
 
-static int ts_usec_delta(struct sip_msg *msg, int *t1s,
-		int *t1u, int *t2s, int *t2u, pv_spec_t *_res);
+static int ts_usec_delta(struct sip_msg *msg, int *t1s, int *t1u,
+		int *t2s, int *t2u, pv_spec_t *pv_delta_str, pv_spec_t *pv_delta_int);
 int check_time_rec(struct sip_msg *_, char *time_rec, unsigned int *ptime);
 
 #ifdef HAVE_TIMER_FD
@@ -182,7 +182,8 @@ static const cmd_export_t cmds[]={
 		{CMD_PARAM_INT, 0, 0},
 		{CMD_PARAM_INT, 0, 0},
 		{CMD_PARAM_INT, 0, 0},
-		{CMD_PARAM_VAR, fixup_check_pv_setf, 0}, {0,0,0}},
+		{CMD_PARAM_VAR|CMD_PARAM_OPT, fixup_check_pv_setf, 0},
+		{CMD_PARAM_VAR|CMD_PARAM_OPT, fixup_check_pv_setf, 0}, {0,0,0}},
 		REQUEST_ROUTE|FAILURE_ROUTE|ONREPLY_ROUTE|BRANCH_ROUTE|LOCAL_ROUTE|
 		STARTUP_ROUTE|TIMER_ROUTE|EVENT_ROUTE},
 	{"get_static_lock",(cmd_function)get_static_lock, {
@@ -307,8 +308,8 @@ struct module_exports exports = {
 
 static int fixup_check_pv_setf(void **param)
 {
-	if (((pv_spec_t*)*param)->setf == 0) {
-		LM_ERR("invalid pvar\n");
+	if (!pv_is_w(((pv_spec_t*)*param))) {
+		LM_ERR("invalid pvar: must be writable\n");
 		return E_SCRIPT;
 	}
 
@@ -824,18 +825,44 @@ static int pv_sel_weight(struct sip_msg* msg, pv_spec_t *pv_name)
 	return -1;
 }
 
-static int ts_usec_delta(struct sip_msg *msg, int *t1s,
-		int *t1u, int *t2s, int *t2u, pv_spec_t *_res)
+static int ts_usec_delta(struct sip_msg *msg, int *t1s, int *t1u,
+		int *t2s, int *t2u, pv_spec_t *pv_delta_str, pv_spec_t *pv_delta_int)
 {
-	pv_value_t res;
+	pv_value_t val;
+	long long diff;
 
-	res.ri = abs(1000000 * (*t1s - *t2s) + *t1u - *t2u);
-	res.flags = PV_TYPE_INT;
+	diff = llabs(1000000LL * (*t1s - *t2s) + *t1u - *t2u);
 
-	if (pv_set_value(msg, _res, 0, &res)) {
-		LM_ERR("cannot store result value\n");
-		return -1;
+	if (pv_delta_str) {
+		char diff_buf[20 + 1];
+
+		val.rs.s = diff_buf;
+		val.rs.len = sprintf(diff_buf, "%lld", diff);
+		val.flags = PV_VAL_STR;
+
+		if (pv_set_value(msg, pv_delta_str, 0, &val) != 0) {
+			LM_ERR("failed to set the 'delta_str' output variable\n");
+			return -1;
+		}
+	}
+
+	if (pv_delta_int) {
+		if (diff > INT_MAX) {
+			LM_ERR("diff is too large to store in 'delta_int' (%lld us), "
+			       "use the 'delta_str' output variable instead!\n", diff);
+			return -1;
+		}
+
+		val.rs = STR_NULL;
+		val.ri = (int)diff;
+		val.flags = PV_VAL_INT|PV_TYPE_INT;
+
+		if (pv_set_value(msg, pv_delta_int, 0, &val)) {
+			LM_ERR("failed to set the 'delta_int' output variable\n");
+			return -1;
+		}
 	}
+
 	return 1;
 }
 

modules/cfgutils/doc/cfgutils_admin.xml

@@ -473,12 +473,18 @@ $var(next_gw_idx) = set_select_weight($avp(gw_success_rates));
 	</section>
 	<section id="func_ts_usec_delta" xreflabel="ts_usec_delta()">
 		<title>
-			<function moreinfo="none">ts_usec_delta(t1_sec, t1_usec, t2_sec, t2_usec, delta)</function>
+			<function moreinfo="none">ts_usec_delta(t1_sec, t1_usec, t2_sec, t2_usec, [delta_str], [delta_int])</function>
 		</title>
 		<para>
-			This function returns the difference between two timestamps, specified
-			in seconds and microseconds. The result is returned in the last
-			parameter, expressed in microseconds.
+			This function returns the absolute difference between the two given
+			timestamps. The result is expressed as <emphasis>microseconds</emphasis>
+			and can be returned as either string or integer.
+		</para>
+		<para>
+			<emphasis role='bold'>WARNING:</emphasis> when using
+			<emphasis>delta_int</emphasis>, the function will return error code
+			<emphasis role='bold'>-1</emphasis> in case the difference overflows
+			the signed integer holder! (i.e. a diff of ~35 minutes or more)
 		</para>
 		<para>
 			This function can be used from REQUEST_ROUTE, ONREPLY_ROUTE, 
@@ -488,7 +494,7 @@ $var(next_gw_idx) = set_select_weight($avp(gw_success_rates));
 			<title><function>ts_usec_delta</function> usage</title>
 			<programlisting format="linespecific">
 ...
-ts_usec_delta($var(t1s), 300, 10, $var(t2ms), $var(result));
+ts_usec_delta($var(t1s), 300, 10, $var(t2us), $var(diff_str));
 ...
 			</programlisting>
 		</example>