Make signal handler setup/teardown two common functions instead of six,

and reset SIGCHLD after fork to fix problems with some shells. From
Romain Francois.

Makefile

@@ -35,7 +35,7 @@ SRCS=	attributes.c cfg.c client.c clock.c \
 	layout-set.c layout-string.c layout.c log.c job.c \
 	mode-key.c names.c options.c paste.c procname.c \
 	resize.c screen-redraw.c screen-write.c screen.c session.c status.c \
-	server-fn.c server.c server-client.c server-window.c \
+	server-fn.c server.c server-client.c server-window.c signal.c \
 	tmux.c tty-keys.c tty-term.c tty.c utf8.c \
 	window-choose.c window-clock.c window-copy.c window.c \
 	xterm-keys.c xmalloc.c

client.c

@@ -172,35 +172,12 @@ client_update_event(void)
 __dead void
 client_main(void)
 {
-	struct event		ev_sigcont, ev_sigterm, ev_sigwinch;
-	struct sigaction	sigact;
-
 	logfile("client");
 
 	/* Note: event_init() has already been called. */
 
 	/* Set up signals. */
-	memset(&sigact, 0, sizeof sigact);
-	sigemptyset(&sigact.sa_mask);
-	sigact.sa_flags = SA_RESTART;
-	sigact.sa_handler = SIG_IGN;
-	if (sigaction(SIGINT, &sigact, NULL) != 0)
-		fatal("sigaction failed");
-	if (sigaction(SIGPIPE, &sigact, NULL) != 0)
-		fatal("sigaction failed");
-	if (sigaction(SIGUSR1, &sigact, NULL) != 0)
-		fatal("sigaction failed");
-	if (sigaction(SIGUSR2, &sigact, NULL) != 0)
-		fatal("sigaction failed");
-	if (sigaction(SIGTSTP, &sigact, NULL) != 0)
-		fatal("sigaction failed");
-
-	signal_set(&ev_sigcont, SIGCONT, client_signal, NULL);
-	signal_add(&ev_sigcont, NULL);
-	signal_set(&ev_sigterm, SIGTERM, client_signal, NULL);
-	signal_add(&ev_sigterm, NULL);
-	signal_set(&ev_sigwinch, SIGWINCH, client_signal, NULL);
-	signal_add(&ev_sigwinch, NULL);
+	set_signals(client_signal);
 
 	/*
 	 * imsg_read in the first client poll loop (before the terminal has

cmd-pipe-pane.c

@@ -91,7 +91,7 @@ cmd_pipe_pane_exec(struct cmd *self, struct cmd_ctx *ctx)
 	case 0:
 		/* Child process. */
 		close(pipe_fd[0]);
-		server_signal_clear();
+		clear_signals();
 
 		if (dup2(pipe_fd[1], STDIN_FILENO) == -1)
 			_exit(1);

job.c

@@ -149,7 +149,7 @@ job_run(struct job *job)
 	case -1:
 		return (-1);
 	case 0:		/* child */
-		server_signal_clear();
+		clear_signals();
 
 		environ_push(&global_environ);
 

server.c

@@ -49,9 +49,6 @@ struct clients	 dead_clients;
 int		 server_fd;
 int		 server_shutdown;
 struct event	 server_ev_accept;
-struct event	 server_ev_sigterm;
-struct event	 server_ev_sigusr1;
-struct event	 server_ev_sigchld;
 struct event	 server_ev_second;
 
 int		 server_create_socket(void);
@@ -134,6 +131,12 @@ server_start(char *path)
 	}
 	close(pair[0]);
 
+	/* event_init() was called by the parent, need to reinit. */
+	if (event_reinit(ev_base) != 0)
+		fatal("event_reinit failed");
+
+	clear_signals();
+
 	/*
 	 * Must daemonise before loading configuration as the PID changes so
 	 * $TMUX would be wrong for sessions created in the config file.
@@ -162,8 +165,6 @@ server_start(char *path)
 	log_debug("socket path %s", socket_path);
 	setproctitle("server (%s)", rpathbuf);
 
-	event_init();
-
 	server_fd = server_create_socket();
 	server_client_create(pair[1]);
 
@@ -202,7 +203,7 @@ server_start(char *path)
 	evtimer_set(&server_ev_second, server_second_callback, NULL);
 	evtimer_add(&server_ev_second, &tv);
 
-	server_signal_set();
+	set_signals(server_signal_callback);
 	server_loop();
 	exit(0);
 }
@@ -341,61 +342,6 @@ server_accept_callback(int fd, short events, unused void *data)
 	server_client_create(newfd);
 }
 
-/* Set up server signal handling. */
-void
-server_signal_set(void)
-{
-	struct sigaction	 sigact;
-
-	memset(&sigact, 0, sizeof sigact);
-	sigemptyset(&sigact.sa_mask);
-	sigact.sa_flags = SA_RESTART;
-	sigact.sa_handler = SIG_IGN;
-	if (sigaction(SIGINT, &sigact, NULL) != 0)
-		fatal("sigaction failed");
-	if (sigaction(SIGPIPE, &sigact, NULL) != 0)
-		fatal("sigaction failed");
-	if (sigaction(SIGUSR2, &sigact, NULL) != 0)
-		fatal("sigaction failed");
-	if (sigaction(SIGTSTP, &sigact, NULL) != 0)
-		fatal("sigaction failed");
-	if (sigaction(SIGHUP, &sigact, NULL) != 0)
-		fatal("sigaction failed");
-
-	signal_set(&server_ev_sigchld, SIGCHLD, server_signal_callback, NULL);
-	signal_add(&server_ev_sigchld, NULL);
-	signal_set(&server_ev_sigterm, SIGTERM, server_signal_callback, NULL);
-	signal_add(&server_ev_sigterm, NULL);
-	signal_set(&server_ev_sigusr1, SIGUSR1, server_signal_callback, NULL);
-	signal_add(&server_ev_sigusr1, NULL);
-}
-
-/* Destroy server signal events. */
-void
-server_signal_clear(void)
-{
-	struct sigaction	 sigact;
-
-	memset(&sigact, 0, sizeof sigact);
-	sigemptyset(&sigact.sa_mask);
-	sigact.sa_flags = SA_RESTART;
-	sigact.sa_handler = SIG_DFL;
-	if (sigaction(SIGINT, &sigact, NULL) != 0)
-		fatal("sigaction failed");
-	if (sigaction(SIGPIPE, &sigact, NULL) != 0)
-		fatal("sigaction failed");
-	if (sigaction(SIGUSR2, &sigact, NULL) != 0)
-		fatal("sigaction failed");
-	if (sigaction(SIGTSTP, &sigact, NULL) != 0)
-		fatal("sigaction failed");
-	if (sigaction(SIGHUP, &sigact, NULL) != 0)
-		fatal("sigaction failed");
-
-	signal_del(&server_ev_sigchld);
-	signal_del(&server_ev_sigterm);
-	signal_del(&server_ev_sigusr1);
-}
-
 /* Signal handler. */
 /* ARGSUSED */
 void

signal.c

@@ -0,0 +1,90 @@
+/* $OpenBSD$ */
+
+/*
+ * Copyright (c) 2007 Nicholas Marriott <nicm@users.sourceforge.net>
+ * Copyright (c) 2010 Romain Francoise <rfrancoise@debian.org>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF MIND, USE, DATA OR PROFITS, WHETHER
+ * IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
+ * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <sys/types.h>
+
+#include <signal.h>
+#include <string.h>
+
+#include "tmux.h"
+
+struct event	ev_sigchld;
+struct event	ev_sigcont;
+struct event	ev_sigterm;
+struct event	ev_sigusr1;
+struct event	ev_sigwinch;
+
+void
+set_signals(void(*handler)(int, short, void *))
+{
+	struct sigaction	sigact;
+
+	memset(&sigact, 0, sizeof sigact);
+	sigemptyset(&sigact.sa_mask);
+	sigact.sa_flags = SA_RESTART;
+	sigact.sa_handler = SIG_IGN;
+	if (sigaction(SIGINT, &sigact, NULL) != 0)
+		fatal("sigaction failed");
+	if (sigaction(SIGPIPE, &sigact, NULL) != 0)
+		fatal("sigaction failed");
+	if (sigaction(SIGUSR2, &sigact, NULL) != 0)
+		fatal("sigaction failed");
+	if (sigaction(SIGTSTP, &sigact, NULL) != 0)
+		fatal("sigaction failed");
+	if (sigaction(SIGHUP, &sigact, NULL) != 0)
+		fatal("sigaction failed");
+
+	signal_set(&ev_sigchld, SIGCHLD, handler, NULL);
+	signal_add(&ev_sigchld, NULL);
+	signal_set(&ev_sigcont, SIGCONT, handler, NULL);
+	signal_add(&ev_sigcont, NULL);
+	signal_set(&ev_sigterm, SIGTERM, handler, NULL);
+	signal_add(&ev_sigterm, NULL);
+	signal_set(&ev_sigusr1, SIGUSR1, handler, NULL);
+	signal_add(&ev_sigusr1, NULL);
+	signal_set(&ev_sigwinch, SIGWINCH, handler, NULL);
+	signal_add(&ev_sigwinch, NULL);
+}
+
+void
+clear_signals(void)
+{
+	struct sigaction	sigact;
+
+	memset(&sigact, 0, sizeof sigact);
+	sigemptyset(&sigact.sa_mask);
+	sigact.sa_flags = SA_RESTART;
+	sigact.sa_handler = SIG_DFL;
+	if (sigaction(SIGINT, &sigact, NULL) != 0)
+		fatal("sigaction failed");
+	if (sigaction(SIGPIPE, &sigact, NULL) != 0)
+		fatal("sigaction failed");
+	if (sigaction(SIGUSR2, &sigact, NULL) != 0)
+		fatal("sigaction failed");
+	if (sigaction(SIGTSTP, &sigact, NULL) != 0)
+		fatal("sigaction failed");
+	if (sigaction(SIGHUP, &sigact, NULL) != 0)
+		fatal("sigaction failed");
+
+	event_del(&ev_sigchld);
+	event_del(&ev_sigcont);
+	event_del(&ev_sigterm);
+	event_del(&ev_sigusr1);
+	event_del(&ev_sigwinch);
+}

tmux.c

@@ -18,6 +18,7 @@
 
 #include <sys/types.h>
 #include <sys/stat.h>
+#include <sys/wait.h>
 
 #include <errno.h>
 #include <event.h>
@@ -41,6 +42,8 @@ struct options	 global_s_options;	/* session options */
 struct options	 global_w_options;	/* window options */
 struct environ	 global_environ;
 
+struct event_base *ev_base;
+
 int		 debug_level;
 time_t		 start_time;
 char		*socket_path;
@@ -58,11 +61,8 @@ char 		*makesockpath(const char *);
 __dead void	 shell_exec(const char *, const char *);
 
 struct imsgbuf	*main_ibuf;
-struct event	 main_ev_sigterm;
 int	         main_exitval;
 
-void		 main_set_signals(void);
-void		 main_clear_signals(void);
 void		 main_signal(int, short, unused void *);
 void		 main_callback(int, short, void *);
 void		 main_dispatch(const char *);
@@ -238,7 +238,6 @@ main(int argc, char **argv)
 	struct keylist		*keylist;
 	struct env_data		 envdata;
 	struct msg_command_data	 cmddata;
-	struct sigaction	 sigact;
 	char			*s, *shellcmd, *path, *label, *home, *cause;
 	char			 cwd[MAXPATHLEN], **var;
 	void			*buf;
@@ -538,24 +537,22 @@ main(int argc, char **argv)
 		exit(1);
 	}
 
-	/* Catch SIGCHLD to avoid a zombie when starting the server. */
-	memset(&sigact, 0, sizeof sigact);
-	sigemptyset(&sigact.sa_mask);
-	sigact.sa_handler = SIG_IGN;
-	if (sigaction(SIGCHLD, &sigact, NULL) != 0)
-		fatal("sigaction failed");
+	/* Initialise the client socket/start the server. */
+	if ((main_ibuf = client_init(path, cmdflags, flags)) == NULL)
+		exit(1);
+	xfree(path);
+
+	ev_base = event_init();
+
+	set_signals(main_signal);
 
 	/* Initialise the client socket/start the server. */
 	if ((main_ibuf = client_init(path, cmdflags, flags)) == NULL)
 		exit(1);
 	xfree(path);
 
-	event_init();
-
 	imsg_compose(main_ibuf, msg, PROTOCOL_VERSION, -1, -1, buf, len);
 
-	main_set_signals();
-
 	events = EV_READ;
 	if (main_ibuf->w.queued > 0)
 		events |= EV_WRITE;
@@ -564,58 +561,11 @@ main(int argc, char **argv)
 	main_exitval = 0;
 	event_dispatch();
 
-	main_clear_signals();
+	clear_signals();
 
 	client_main();	/* doesn't return */
 }
 
-void
-main_set_signals(void)
-{
-	struct sigaction	sigact;
-
-	memset(&sigact, 0, sizeof sigact);
-	sigemptyset(&sigact.sa_mask);
-	sigact.sa_flags = SA_RESTART;
-	sigact.sa_handler = SIG_IGN;
-	if (sigaction(SIGINT, &sigact, NULL) != 0)
-		fatal("sigaction failed");
-	if (sigaction(SIGPIPE, &sigact, NULL) != 0)
-		fatal("sigaction failed");
-	if (sigaction(SIGUSR1, &sigact, NULL) != 0)
-		fatal("sigaction failed");
-	if (sigaction(SIGUSR2, &sigact, NULL) != 0)
-		fatal("sigaction failed");
-	if (sigaction(SIGTSTP, &sigact, NULL) != 0)
-		fatal("sigaction failed");
-
-	signal_set(&main_ev_sigterm, SIGTERM, main_signal, NULL);
-	signal_add(&main_ev_sigterm, NULL);
-}
-
-void
-main_clear_signals(void)
-{
-	struct sigaction	sigact;
-
-	memset(&sigact, 0, sizeof sigact);
-	sigemptyset(&sigact.sa_mask);
-	sigact.sa_flags = SA_RESTART;
-	sigact.sa_handler = SIG_DFL;
-	if (sigaction(SIGINT, &sigact, NULL) != 0)
-		fatal("sigaction failed");
-	if (sigaction(SIGPIPE, &sigact, NULL) != 0)
-		fatal("sigaction failed");
-	if (sigaction(SIGUSR1, &sigact, NULL) != 0)
-		fatal("sigaction failed");
-	if (sigaction(SIGUSR2, &sigact, NULL) != 0)
-		fatal("sigaction failed");
-	if (sigaction(SIGTSTP, &sigact, NULL) != 0)
-		fatal("sigaction failed");
-
-	event_del(&main_ev_sigterm);
-}
-
 /* ARGSUSED */
 void
 main_signal(int sig, unused short events, unused void *data)
@@ -623,6 +573,9 @@ main_signal(int sig, unused short events, unused void *data)
 	switch (sig) {
 	case SIGTERM:
 		exit(1);
+	case SIGCHLD:
+		waitpid(WAIT_ANY, NULL, WNOHANG);
+		break;
 	}
 }
 
@@ -701,7 +654,7 @@ main_dispatch(const char *shellcmd)
 			memcpy(&shelldata, imsg.data, sizeof shelldata);
 			shelldata.shell[(sizeof shelldata.shell) - 1] = '\0';
 
-			main_clear_signals();
+			clear_signals();
 
 			shell_exec(shelldata.shell, shellcmd);
 		default:

tmux.h

@@ -1253,6 +1253,7 @@ extern struct options global_options;
 extern struct options global_s_options;
 extern struct options global_w_options;
 extern struct environ global_environ;
+extern struct event_base *ev_base;
 extern char	*cfg_file;
 extern int	 debug_level;
 extern int	 be_quiet;
@@ -1583,8 +1584,6 @@ const char *key_string_lookup_key(int);
 extern struct clients clients;
 extern struct clients dead_clients;
 int	 server_start(char *);
-void	 server_signal_set(void);
-void	 server_signal_clear(void);
 void	 server_update_socket(void);
 
 /* server-client.c */
@@ -1900,6 +1899,10 @@ void		 window_choose_ready(struct window_pane *,
 void		 queue_window_name(struct window *);
 char		*default_window_name(struct window *);
 
+/* signal.c */
+void		 set_signals(void(*)(int, short, void *));
+void		 clear_signals(void);
+
 /* session.c */
 extern struct sessions sessions;
 extern struct sessions dead_sessions;

window.c

@@ -529,7 +529,7 @@ window_pane_spawn(struct window_pane *wp, const char *cmd, const char *shell,
 
 		environ_push(env);
 
-		server_signal_clear();
+		clear_signals();
 		log_close();
 
 		if (*wp->cmd != '\0') {