[core] lighttpd -1 handles single request on stdin socket (fixes #1584)

(e.g. when called from xinetd)

Note: lighttpd is designed as a high performance, long-running server,
not a one-shot executable.  This one-shot mode of operation has not been
tuned for performance.  lighttpd server start-up and initialization aims
for correctness, not speed.  If using this one-shot mode as part of fork
and exec from xinetd, then performance is already not of high concern.

x-ref:
  "support for xinetd"
  https://redmine.lighttpd.net/issues/1584

doc/lighttpd.8

@@ -42,6 +42,9 @@ Do not daemonize (go into background). The default is to daemonize.
 \fB\-i\ \fP \fIsecs\fP
 Trigger daemon graceful shutdown after \fIsecs\fP of inactivity.
 .TP 8
+\fB\-1\fP
+Process single (one) request on stdin socket, then exit.
+.TP 8
 \fB\-v\fP
 Show version and exit.
 .TP 8

src/connections.c

@@ -894,6 +894,11 @@ connection *connection_accept(server *srv, server_socket *srv_socket) {
 		}
 		return NULL;
 	} else {
+		return connection_accepted(srv, srv_socket, &cnt_addr, cnt);
+	}
+}
+
+connection *connection_accepted(server *srv, server_socket *srv_socket, sock_addr *cnt_addr, int cnt) {
 		connection *con;
 
 		srv->cur_fds++;
@@ -917,7 +922,7 @@ connection *connection_accept(server *srv, server_socket *srv_socket) {
 		connection_set_state(srv, con, CON_STATE_REQUEST_START);
 
 		con->connection_start = srv->cur_ts;
-		con->dst_addr = cnt_addr;
+		con->dst_addr = *cnt_addr;
 		buffer_copy_string(con->dst_addr_buf, inet_ntop_cache_get_ip(srv, &(con->dst_addr)));
 		con->srv_socket = srv_socket;
 
@@ -947,7 +952,6 @@ connection *connection_accept(server *srv, server_socket *srv_socket) {
 		}
 #endif
 		return con;
-	}
 }
 
 

src/connections.h

@@ -10,6 +10,7 @@ int connection_reset(server *srv, connection *con);
 void connections_free(server *srv);
 
 connection * connection_accept(server *srv, server_socket *srv_sock);
+connection * connection_accepted(server *srv, server_socket *srv_socket, sock_addr *cnt_addr, int cnt);
 
 int connection_set_state(server *srv, connection *con, connection_state_t state);
 const char * connection_get_state(connection_state_t state);

src/network.c

@@ -334,6 +334,13 @@ static int network_server_init(server *srv, buffer *host_token, specific_config
 		goto error_free_socket;
 	}
 
+	if (srv->sockets_disabled) { /* lighttpd -1 (one-shot mode) */
+#ifdef USE_OPENSSL
+		if (s->ssl_enabled) srv_socket->ssl_ctx = s->ssl_ctx;
+#endif
+		goto srv_sockets_append;
+	}
+
 #ifdef HAVE_SYS_UN_H
 	if (AF_UNIX == srv_socket->addr.plain.sa_family) {
 		/* check if the socket exists and try to connect to it. */
@@ -455,6 +462,7 @@ static int network_server_init(server *srv, buffer *host_token, specific_config
 #endif
 	}
 
+srv_sockets_append:
 	srv_socket->is_ssl = s->ssl_enabled;
 
 	if (srv->srv_sockets.size == 0) {
@@ -1026,6 +1034,8 @@ int network_register_fdevents(server *srv) {
 		return -1;
 	}
 
+	if (srv->sockets_disabled) return 0; /* lighttpd -1 (one-shot mode) */
+
 	/* register fdevents after reset */
 	for (i = 0; i < srv->srv_sockets.used; i++) {
 		server_socket *srv_socket = srv->srv_sockets.ptr[i];

src/server.c

@@ -424,6 +424,110 @@ static void remove_pid_file(server *srv, int *pid_fd) {
 	}
 }
 
+
+static server_socket * server_oneshot_getsock(server *srv, sock_addr *cnt_addr) {
+	server_socket *srv_socket, *srv_socket_wild = NULL;
+	size_t i;
+	for (i = 0; i < srv->srv_sockets.used; ++i) {
+		srv_socket = srv->srv_sockets.ptr[i];
+		if (cnt_addr->plain.sa_family != srv_socket->addr.plain.sa_family) continue;
+		switch (cnt_addr->plain.sa_family) {
+		case AF_INET:
+			if (srv_socket->addr.ipv4.sin_port != cnt_addr->ipv4.sin_port) continue;
+			if (srv_socket->addr.ipv4.sin_addr.s_addr == cnt_addr->ipv4.sin_addr.s_addr) {
+				return srv_socket;
+			}
+			if (srv_socket->addr.ipv4.sin_addr.s_addr == htonl(INADDR_ANY)) {
+				srv_socket_wild = srv_socket;
+			}
+			continue;
+		#ifdef HAVE_IPV6
+		case AF_INET6:
+			if (srv_socket->addr.ipv6.sin6_port != cnt_addr->ipv6.sin6_port) continue;
+			if (0 == memcmp(&srv_socket->addr.ipv6.sin6_addr, &cnt_addr->ipv6.sin6_addr, sizeof(struct in6_addr))) {
+				return srv_socket;
+			}
+			if (0 == memcmp(&srv_socket->addr.ipv6.sin6_addr, &in6addr_any, sizeof(struct in6_addr))) {
+				srv_socket_wild = srv_socket;
+			}
+			continue;
+		#endif
+		#ifdef HAVE_SYS_UN_H
+		case AF_UNIX:
+			if (0 == strcmp(srv_socket->addr.un.sun_path, cnt_addr->un.sun_path)) {
+				return srv_socket;
+			}
+			continue;
+		#endif
+		default: continue;
+		}
+	}
+
+	if (NULL != srv_socket_wild) {
+		return srv_socket_wild;
+	} else if (srv->srv_sockets.used) {
+		return srv->srv_sockets.ptr[0];
+	} else {
+		log_error_write(srv, __FILE__, __LINE__, "s", "no sockets configured");
+		return NULL;
+	}
+}
+
+
+static int server_oneshot_init(server *srv, int fd) {
+	/* Note: does not work with netcat due to requirement that fd be socket.
+	 * STDOUT_FILENO was not saved earlier in startup, and that is to where
+	 * netcat expects output to be sent.  Since lighttpd expects connections
+	 * to be sockets, con->fd is where output is sent; separate fds are not
+	 * stored for input and output, but netcat has different fds for stdin
+	 * and * stdout.  To support netcat, would additionally need to avoid
+	 * S_ISSOCK(), getsockname(), and getpeername() below, reconstructing
+	 * addresses from environment variables:
+	 *   NCAT_LOCAL_ADDR   NCAT_LOCAL_PORT
+	 *   NCAT_REMOTE_ADDR  NCAT_REMOTE_PORT
+	 *   NCAT_PROTO
+	 */
+	connection *con;
+	server_socket *srv_socket;
+	sock_addr cnt_addr;
+	socklen_t cnt_len;
+	struct stat st;
+
+	if (0 != fstat(fd, &st)) {
+		log_error_write(srv, __FILE__, __LINE__, "ss", "fstat:", strerror(errno));
+		return 0;
+	}
+
+	if (!S_ISSOCK(st.st_mode)) {
+		/* require that fd is a socket
+		 * (modules might expect STDIN_FILENO and STDOUT_FILENO opened to /dev/null) */
+		log_error_write(srv, __FILE__, __LINE__, "s", "lighttpd -1 stdin is not a socket");
+		return 0;
+	}
+
+	cnt_len = sizeof(cnt_addr);
+	if (0 != getsockname(fd, (struct sockaddr *)&cnt_addr, &cnt_len)) {
+		log_error_write(srv, __FILE__, __LINE__, "ss", "getsockname:", strerror(errno));
+		return 0;
+	}
+
+	srv_socket = server_oneshot_getsock(srv, &cnt_addr);
+	if (NULL == srv_socket) return 0;
+
+	cnt_len = sizeof(cnt_addr);
+	if (0 != getpeername(fd, (struct sockaddr *)&cnt_addr, &cnt_len)) {
+		log_error_write(srv, __FILE__, __LINE__, "ss", "getpeername:", strerror(errno));
+		return 0;
+	}
+
+	con = connection_accepted(srv, srv_socket, &cnt_addr, fd);
+	if (NULL == con) return 0;
+
+	connection_state_machine(srv, con);
+	return 1;
+}
+
+
 static void show_version (void) {
 #ifdef USE_OPENSSL
 # define TEXT_SSL " (ssl)"
@@ -600,6 +704,7 @@ static void show_help (void) {
 " -f <name>  filename of the config-file\n" \
 " -m <name>  module directory (default: "LIBRARY_DIR")\n" \
 " -i <secs>  graceful shutdown after <secs> of inactivity\n" \
+" -1         process single (one) request on stdin socket, then exit\n" \
 " -p         print the parsed config-file in internal form, and exit\n" \
 " -t         test the config-file, and exit\n" \
 " -D         don't go to background (default: go to background)\n" \
@@ -633,6 +738,7 @@ int main (int argc, char **argv) {
 #ifdef HAVE_FORK
 	int parent_pipe_fd = -1;
 #endif
+	int oneshot_fd = 0;
 
 #ifdef USE_ALARM
 	struct itimerval interval;
@@ -662,7 +768,7 @@ int main (int argc, char **argv) {
 	srv->srvconf.dont_daemonize = 0;
 	srv->srvconf.preflight_check = 0;
 
-	while(-1 != (o = getopt(argc, argv, "f:m:i:hvVDpt"))) {
+	while(-1 != (o = getopt(argc, argv, "f:m:i:hvVD1pt"))) {
 		switch(o) {
 		case 'f':
 			if (srv->config_storage) {
@@ -694,6 +800,7 @@ int main (int argc, char **argv) {
 		}
 		case 'p': print_config = 1; break;
 		case 't': ++test_config; break;
+		case '1': oneshot_fd = dup(STDIN_FILENO); break;
 		case 'D': srv->srvconf.dont_daemonize = 1; break;
 		case 'v': show_version(); server_free(srv); return 0;
 		case 'V': show_features(); server_free(srv); return 0;
@@ -740,6 +847,24 @@ int main (int argc, char **argv) {
 		return 0;
 	}
 
+	if (oneshot_fd) {
+		if (oneshot_fd <= STDERR_FILENO) {
+			log_error_write(srv, __FILE__, __LINE__, "s",
+					"Invalid fds at startup with lighttpd -1");
+			server_free(srv);
+			return -1;
+		}
+		graceful_shutdown = 1;
+		srv->sockets_disabled = 1;
+		srv->srvconf.dont_daemonize = 1;
+		buffer_reset(srv->srvconf.pid_file);
+		if (srv->srvconf.max_worker) {
+			srv->srvconf.max_worker = 0;
+			log_error_write(srv, __FILE__, __LINE__, "s",
+					"server one-shot command line option disables server.max-worker config file option.");
+		}
+	}
+
 	/* close stdin and stdout, as they are not needed */
 	openDevNull(STDIN_FILENO);
 	openDevNull(STDOUT_FILENO);
@@ -1344,12 +1469,17 @@ int main (int argc, char **argv) {
 
 	for (i = 0; i < srv->srv_sockets.used; i++) {
 		server_socket *srv_socket = srv->srv_sockets.ptr[i];
+		if (srv->sockets_disabled) continue; /* lighttpd -1 (one-shot mode) */
 		if (-1 == fdevent_fcntl_set(srv->ev, srv_socket->fd)) {
 			log_error_write(srv, __FILE__, __LINE__, "ss", "fcntl failed:", strerror(errno));
 			return -1;
 		}
 	}
 
+	if (oneshot_fd && !server_oneshot_init(srv, oneshot_fd)) {
+		close(oneshot_fd);
+	}
+
 	/* main-loop */
 	while (!srv_shutdown) {
 		int n;