[libev/cgi] fix waitpid ECHILD errors in cgi with libev (fixes #2324)

git-svn-id: svn://svn.lighttpd.net/lighttpd/branches/lighttpd-1.4.x@2816 152afb58-edef-0310-8abb-c4023f1b3aa9

NEWS

@@ -15,6 +15,7 @@ NEWS
   * [ssl] add option to honor server cipher order (fixes #2364, BEAST attack)
   * [core] accept dots in ipv6 addresses in host header (fixes #2359)
   * [ssl] fix ssl connection aborts if files are larger than the MAX_WRITE_LIMIT (256kb)
+  * [libev/cgi] fix waitpid ECHILD errors in cgi with libev (fixes #2324)
 
 - 1.4.29 - 2011-07-03
   * Fix mod_proxy waiting for response even if content-length is 0 (fixes #2259)

src/mod_cgi.c

@@ -1288,6 +1288,15 @@ TRIGGER_FUNC(cgi_trigger) {
 #endif
 			break;
 		case -1:
+			if (errno == ECHILD) {
+				/* someone else called waitpid... remove the pid to stop looping the error each time */
+				log_error_write(srv, __FILE__, __LINE__, "s", "cgi child vanished, probably someone else called waitpid");
+
+				cgi_pid_del(srv, p, p->cgi_pid.ptr[ndx]);
+				ndx--;
+				continue;
+			}
+
 			log_error_write(srv, __FILE__, __LINE__, "ss", "waitpid failed: ", strerror(errno));
 
 			return HANDLER_ERROR;

src/server.c

@@ -1120,6 +1120,14 @@ int main (int argc, char **argv) {
 				"s", "fdevent_init failed");
 		return -1;
 	}
+
+	/* libev backend overwrites our SIGCHLD handler and calls waitpid on SIGCHLD; we want our own SIGCHLD handling. */
+#ifdef HAVE_SIGACTION
+	sigaction(SIGCHLD, &act, NULL);
+#elif defined(HAVE_SIGNAL)
+	signal(SIGCHLD,  signal_handler);
+#endif
+
 	/*
 	 * kqueue() is called here, select resets its internals,
 	 * all server sockets get their handlers