ext/pcntl pcntl_signal_get_handler update.

The situation varies from platform to another, thus taking in
account the complexity of it.

Close GH-13902

NEWS

@@ -125,6 +125,8 @@ PHP                                                                        NEWS
 - PCNTL:
   . Added pcntl_setns for Linux. (David Carlier)
   . Added pcntl_getaffinity/pcntl_setaffinity. (David Carlier)
+  . Updated pcntl_get_signal_handler signal id upper limit to be
+    more in line with platforms limits. (David Carlier)
 
 - PCRE:
   . Upgrade bundled pcre2lib to version 10.43. (nielsdos)

ext/pcntl/pcntl.c

@@ -692,8 +692,17 @@ PHP_FUNCTION(pcntl_signal_get_handler)
 		Z_PARAM_LONG(signo)
 	ZEND_PARSE_PARAMETERS_END();
 
-	if (signo < 1 || signo > 32) {
-		zend_argument_value_error(1, "must be between 1 and 32");
+	// note: max signal on mac is SIGUSR2 (31), no real time signals.
+	int sigmax = NSIG - 1;
+#if defined(SIGRTMAX)
+	// oddily enough, NSIG on freebsd reports only 32 whereas SIGRTMIN starts at 65.
+	if (sigmax < SIGRTMAX) {
+		sigmax = SIGRTMAX;
+	}
+#endif
+
+	if (signo < 1 || signo > sigmax) {
+		zend_argument_value_error(1, "must be between 1 and %d", sigmax);
 		RETURN_THROWS();
 	}