Return to client.c CVS log

Up to [local] / src / usr.bin / tmux

It should no longer be necessary to ignore SIGCHLD because it is now
blocked around daemon(), and doing so causes trouble with newer libevent
(it cannot restore the original handler). Reported by Azat Khuzhin in
GitHub issue 3626.

/* $OpenBSD: client.c,v 1.161 2023/07/10 12:00:08 nicm Exp $ */

/*
 * Copyright (c) 2007 Nicholas Marriott <nicholas.marriott@gmail.com>
 *
 * 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 <sys/socket.h>
#include <sys/uio.h>
#include <sys/un.h>
#include <sys/wait.h>

#include <errno.h>
#include <event.h>
#include <fcntl.h>
#include <imsg.h>
#include <signal.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "tmux.h"

static struct tmuxproc	*client_proc;
static struct tmuxpeer	*client_peer;
static uint64_t		 client_flags;
static int		 client_suspended;
static enum {
	CLIENT_EXIT_NONE,
	CLIENT_EXIT_DETACHED,
	CLIENT_EXIT_DETACHED_HUP,
	CLIENT_EXIT_LOST_TTY,
	CLIENT_EXIT_TERMINATED,
	CLIENT_EXIT_LOST_SERVER,
	CLIENT_EXIT_EXITED,
	CLIENT_EXIT_SERVER_EXITED,
	CLIENT_EXIT_MESSAGE_PROVIDED
} client_exitreason = CLIENT_EXIT_NONE;
static int		 client_exitflag;
static int		 client_exitval;
static enum msgtype	 client_exittype;
static const char	*client_exitsession;
static char		*client_exitmessage;
static const char	*client_execshell;
static const char	*client_execcmd;
static int		 client_attached;
static struct client_files client_files = RB_INITIALIZER(&client_files);

static __dead void	 client_exec(const char *,const char *);
static int		 client_get_lock(char *);
static int		 client_connect(struct event_base *, const char *,
			     uint64_t);
static void		 client_send_identify(const char *, const char *,
			     char **, u_int, const char *, int);
static void		 client_signal(int);
static void		 client_dispatch(struct imsg *, void *);
static void		 client_dispatch_attached(struct imsg *);
static void		 client_dispatch_wait(struct imsg *);
static const char	*client_exit_message(void);

/*
 * Get server create lock. If already held then server start is happening in
 * another client, so block until the lock is released and return -2 to
 * retry. Return -1 on failure to continue and start the server anyway.
 */
static int
client_get_lock(char *lockfile)
{
	int lockfd;

	log_debug("lock file is %s", lockfile);

	if ((lockfd = open(lockfile, O_WRONLY|O_CREAT, 0600)) == -1) {
		log_debug("open failed: %s", strerror(errno));
		return (-1);
	}

	if (flock(lockfd, LOCK_EX|LOCK_NB) == -1) {
		log_debug("flock failed: %s", strerror(errno));
		if (errno != EAGAIN)
			return (lockfd);
		while (flock(lockfd, LOCK_EX) == -1 && errno == EINTR)
			/* nothing */;
		close(lockfd);
		return (-2);
	}
	log_debug("flock succeeded");

	return (lockfd);
}

/* Connect client to server. */
static int
client_connect(struct event_base *base, const char *path, uint64_t flags)
{
	struct sockaddr_un	sa;
	size_t			size;
	int			fd, lockfd = -1, locked = 0;
	char		       *lockfile = NULL;

	memset(&sa, 0, sizeof sa);
	sa.sun_family = AF_UNIX;
	size = strlcpy(sa.sun_path, path, sizeof sa.sun_path);
	if (size >= sizeof sa.sun_path) {
		errno = ENAMETOOLONG;
		return (-1);
	}
	log_debug("socket is %s", path);

retry:
	if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1)
		return (-1);

	log_debug("trying connect");
	if (connect(fd, (struct sockaddr *)&sa, sizeof sa) == -1) {
		log_debug("connect failed: %s", strerror(errno));
		if (errno != ECONNREFUSED && errno != ENOENT)
			goto failed;
		if (flags & CLIENT_NOSTARTSERVER)
			goto failed;
		if (~flags & CLIENT_STARTSERVER)
			goto failed;
		close(fd);

		if (!locked) {
			xasprintf(&lockfile, "%s.lock", path);
			if ((lockfd = client_get_lock(lockfile)) < 0) {
				log_debug("didn't get lock (%d)", lockfd);

				free(lockfile);
				lockfile = NULL;

				if (lockfd == -2)
					goto retry;
			}
			log_debug("got lock (%d)", lockfd);

			/*
			 * Always retry at least once, even if we got the lock,
			 * because another client could have taken the lock,
			 * started the server and released the lock between our
			 * connect() and flock().
			 */
			locked = 1;
			goto retry;
		}

		if (lockfd >= 0 && unlink(path) != 0 && errno != ENOENT) {
			free(lockfile);
			close(lockfd);
			return (-1);
		}
		fd = server_start(client_proc, flags, base, lockfd, lockfile);
	}

	if (locked && lockfd >= 0) {
		free(lockfile);
		close(lockfd);
	}
	setblocking(fd, 0);
	return (fd);

failed:
	if (locked) {
		free(lockfile);
		close(lockfd);
	}
	close(fd);
	return (-1);
}

/* Get exit string from reason number. */
const char *
client_exit_message(void)
{
	static char msg[256];

	switch (client_exitreason) {
	case CLIENT_EXIT_NONE:
		break;
	case CLIENT_EXIT_DETACHED:
		if (client_exitsession != NULL) {
			xsnprintf(msg, sizeof msg, "detached "
			    "(from session %s)", client_exitsession);
			return (msg);
		}
		return ("detached");
	case CLIENT_EXIT_DETACHED_HUP:
		if (client_exitsession != NULL) {
			xsnprintf(msg, sizeof msg, "detached and SIGHUP "
			    "(from session %s)", client_exitsession);
			return (msg);
		}
		return ("detached and SIGHUP");
	case CLIENT_EXIT_LOST_TTY:
		return ("lost tty");
	case CLIENT_EXIT_TERMINATED:
		return ("terminated");
	case CLIENT_EXIT_LOST_SERVER:
		return ("server exited unexpectedly");
	case CLIENT_EXIT_EXITED:
		return ("exited");
	case CLIENT_EXIT_SERVER_EXITED:
		return ("server exited");
	case CLIENT_EXIT_MESSAGE_PROVIDED:
		return (client_exitmessage);
	}
	return ("unknown reason");
}

/* Exit if all streams flushed. */
static void
client_exit(void)
{
	if (!file_write_left(&client_files))
		proc_exit(client_proc);
}

/* Client main loop. */
int
client_main(struct event_base *base, int argc, char **argv, uint64_t flags,
    int feat)
{
	struct cmd_parse_result	*pr;
	struct msg_command	*data;
	int			 fd, i;
	const char		*ttynam, *termname, *cwd;
	pid_t			 ppid;
	enum msgtype		 msg;
	struct termios		 tio, saved_tio;
	size_t			 size, linesize = 0;
	ssize_t			 linelen;
	char			*line = NULL, **caps = NULL, *cause;
	u_int			 ncaps = 0;
	struct args_value	*values;

	/* Set up the initial command. */
	if (shell_command != NULL) {
		msg = MSG_SHELL;
		flags |= CLIENT_STARTSERVER;
	} else if (argc == 0) {
		msg = MSG_COMMAND;
		flags |= CLIENT_STARTSERVER;
	} else {
		msg = MSG_COMMAND;

		/*
		 * It's annoying parsing the command string twice (in client
		 * and later in server) but it is necessary to get the start
		 * server flag.
		 */
		values = args_from_vector(argc, argv);
		pr = cmd_parse_from_arguments(values, argc, NULL);
		if (pr->status == CMD_PARSE_SUCCESS) {
			if (cmd_list_any_have(pr->cmdlist, CMD_STARTSERVER))
				flags |= CLIENT_STARTSERVER;
			cmd_list_free(pr->cmdlist);
		} else
			free(pr->error);
		args_free_values(values, argc);
		free(values);
	}

	/* Create client process structure (starts logging). */
	client_proc = proc_start("client");
	proc_set_signals(client_proc, client_signal);

	/* Save the flags. */
	client_flags = flags;
	log_debug("flags are %#llx", (unsigned long long)client_flags);

	/* Initialize the client socket and start the server. */
	fd = client_connect(base, socket_path, client_flags);
	if (fd == -1) {
		if (errno == ECONNREFUSED) {
			fprintf(stderr, "no server running on %s\n",
			    socket_path);
		} else {
			fprintf(stderr, "error connecting to %s (%s)\n",
			    socket_path, strerror(errno));
		}
		return (1);
	}
	client_peer = proc_add_peer(client_proc, fd, client_dispatch, NULL);

	/* Save these before pledge(). */
	if ((cwd = find_cwd()) == NULL && (cwd = find_home()) == NULL)
		cwd = "/";
	if ((ttynam = ttyname(STDIN_FILENO)) == NULL)
		ttynam = "";
	if ((termname = getenv("TERM")) == NULL)
		termname = "";

	/*
	 * Drop privileges for client. "proc exec" is needed for -c and for
	 * locking (which uses system(3)).
	 *
	 * "tty" is needed to restore termios(4) and also for some reason -CC
	 * does not work properly without it (input is not recognised).
	 *
	 * "sendfd" is dropped later in client_dispatch_wait().
	 */
	if (pledge(
	    "stdio rpath wpath cpath unix sendfd proc exec tty",
	    NULL) != 0)
		fatal("pledge failed");

	/* Load terminfo entry if any. */
	if (isatty(STDIN_FILENO) &&
	    *termname != '\0' &&
	    tty_term_read_list(termname, STDIN_FILENO, &caps, &ncaps,
	    &cause) != 0) {
		fprintf(stderr, "%s\n", cause);
		free(cause);
		return (1);
	}

	/* Free stuff that is not used in the client. */
	if (ptm_fd != -1)
		close(ptm_fd);
	options_free(global_options);
	options_free(global_s_options);
	options_free(global_w_options);
	environ_free(global_environ);

	/* Set up control mode. */
	if (client_flags & CLIENT_CONTROLCONTROL) {
		if (tcgetattr(STDIN_FILENO, &saved_tio) != 0) {
			fprintf(stderr, "tcgetattr failed: %s\n",
			    strerror(errno));
			return (1);
		}
		cfmakeraw(&tio);
		tio.c_iflag = ICRNL|IXANY;
		tio.c_oflag = OPOST|ONLCR;
		tio.c_lflag = NOKERNINFO;
		tio.c_cflag = CREAD|CS8|HUPCL;
		tio.c_cc[VMIN] = 1;
		tio.c_cc[VTIME] = 0;
		cfsetispeed(&tio, cfgetispeed(&saved_tio));
		cfsetospeed(&tio, cfgetospeed(&saved_tio));
		tcsetattr(STDIN_FILENO, TCSANOW, &tio);
	}

	/* Send identify messages. */
	client_send_identify(ttynam, termname, caps, ncaps, cwd, feat);
	tty_term_free_list(caps, ncaps);
	proc_flush_peer(client_peer);

	/* Send first command. */
	if (msg == MSG_COMMAND) {
		/* How big is the command? */
		size = 0;
		for (i = 0; i < argc; i++)
			size += strlen(argv[i]) + 1;
		if (size > MAX_IMSGSIZE - (sizeof *data)) {
			fprintf(stderr, "command too long\n");
			return (1);
		}
		data = xmalloc((sizeof *data) + size);

		/* Prepare command for server. */
		data->argc = argc;
		if (cmd_pack_argv(argc, argv, (char *)(data + 1), size) != 0) {
			fprintf(stderr, "command too long\n");
			free(data);
			return (1);
		}
		size += sizeof *data;

		/* Send the command. */
		if (proc_send(client_peer, msg, -1, data, size) != 0) {
			fprintf(stderr, "failed to send command\n");
			free(data);
			return (1);
		}
		free(data);
	} else if (msg == MSG_SHELL)
		proc_send(client_peer, msg, -1, NULL, 0);

	/* Start main loop. */
	proc_loop(client_proc, NULL);

	/* Run command if user requested exec, instead of exiting. */
	if (client_exittype == MSG_EXEC) {
		if (client_flags & CLIENT_CONTROLCONTROL)
			tcsetattr(STDOUT_FILENO, TCSAFLUSH, &saved_tio);
		client_exec(client_execshell, client_execcmd);
	}

	/* Restore streams to blocking. */
	setblocking(STDIN_FILENO, 1);
	setblocking(STDOUT_FILENO, 1);
	setblocking(STDERR_FILENO, 1);

	/* Print the exit message, if any, and exit. */
	if (client_attached) {
		if (client_exitreason != CLIENT_EXIT_NONE)
			printf("[%s]\n", client_exit_message());

		ppid = getppid();
		if (client_exittype == MSG_DETACHKILL && ppid > 1)
			kill(ppid, SIGHUP);
	} else if (client_flags & CLIENT_CONTROL) {
		if (client_exitreason != CLIENT_EXIT_NONE)
			printf("%%exit %s\n", client_exit_message());
		else
			printf("%%exit\n");
		fflush(stdout);
		if (client_flags & CLIENT_CONTROL_WAITEXIT) {
			setvbuf(stdin, NULL, _IOLBF, 0);
			for (;;) {
				linelen = getline(&line, &linesize, stdin);
				if (linelen <= 1)
					break;
			}
			free(line);
		}
		if (client_flags & CLIENT_CONTROLCONTROL) {
			printf("\033\\");
			fflush(stdout);
			tcsetattr(STDOUT_FILENO, TCSAFLUSH, &saved_tio);
		}
	} else if (client_exitreason != CLIENT_EXIT_NONE)
		fprintf(stderr, "%s\n", client_exit_message());
	return (client_exitval);
}

/* Send identify messages to server. */
static void
client_send_identify(const char *ttynam, const char *termname, char **caps,
    u_int ncaps, const char *cwd, int feat)
{
	char	**ss;
	size_t	  sslen;
	int	  fd, flags = client_flags;
	pid_t	  pid;
	u_int	  i;

	proc_send(client_peer, MSG_IDENTIFY_FLAGS, -1, &flags, sizeof flags);
	proc_send(client_peer, MSG_IDENTIFY_LONGFLAGS, -1, &client_flags,
	    sizeof client_flags);

	proc_send(client_peer, MSG_IDENTIFY_TERM, -1, termname,
	    strlen(termname) + 1);
	proc_send(client_peer, MSG_IDENTIFY_FEATURES, -1, &feat, sizeof feat);

	proc_send(client_peer, MSG_IDENTIFY_TTYNAME, -1, ttynam,
	    strlen(ttynam) + 1);
	proc_send(client_peer, MSG_IDENTIFY_CWD, -1, cwd, strlen(cwd) + 1);

	for (i = 0; i < ncaps; i++) {
		proc_send(client_peer, MSG_IDENTIFY_TERMINFO, -1,
		    caps[i], strlen(caps[i]) + 1);
	}

	if ((fd = dup(STDIN_FILENO)) == -1)
		fatal("dup failed");
	proc_send(client_peer, MSG_IDENTIFY_STDIN, fd, NULL, 0);
	if ((fd = dup(STDOUT_FILENO)) == -1)
		fatal("dup failed");
	proc_send(client_peer, MSG_IDENTIFY_STDOUT, fd, NULL, 0);

	pid = getpid();
	proc_send(client_peer, MSG_IDENTIFY_CLIENTPID, -1, &pid, sizeof pid);

	for (ss = environ; *ss != NULL; ss++) {
		sslen = strlen(*ss) + 1;
		if (sslen > MAX_IMSGSIZE - IMSG_HEADER_SIZE)
			continue;
		proc_send(client_peer, MSG_IDENTIFY_ENVIRON, -1, *ss, sslen);
	}

	proc_send(client_peer, MSG_IDENTIFY_DONE, -1, NULL, 0);
}

/* Run command in shell; used for -c. */
static __dead void
client_exec(const char *shell, const char *shellcmd)
{
	const char	*name, *ptr;
	char		*argv0;

	log_debug("shell %s, command %s", shell, shellcmd);

	ptr = strrchr(shell, '/');
	if (ptr != NULL && *(ptr + 1) != '\0')
		name = ptr + 1;
	else
		name = shell;
	if (client_flags & CLIENT_LOGIN)
		xasprintf(&argv0, "-%s", name);
	else
		xasprintf(&argv0, "%s", name);
	setenv("SHELL", shell, 1);

	proc_clear_signals(client_proc, 1);

	setblocking(STDIN_FILENO, 1);
	setblocking(STDOUT_FILENO, 1);
	setblocking(STDERR_FILENO, 1);
	closefrom(STDERR_FILENO + 1);

	execl(shell, argv0, "-c", shellcmd, (char *) NULL);
	fatal("execl failed");
}

/* Callback to handle signals in the client. */
static void
client_signal(int sig)
{
	struct sigaction sigact;
	int		 status;
	pid_t		 pid;

	log_debug("%s: %s", __func__, strsignal(sig));
	if (sig == SIGCHLD) {
		for (;;) {
			pid = waitpid(WAIT_ANY, &status, WNOHANG);
			if (pid == 0)
				break;
			if (pid == -1) {
				if (errno == ECHILD)
					break;
				log_debug("waitpid failed: %s",
				    strerror(errno));
			}
		}
	} else if (!client_attached) {
		if (sig == SIGTERM || sig == SIGHUP)
			proc_exit(client_proc);
	} else {
		switch (sig) {
		case SIGHUP:
			client_exitreason = CLIENT_EXIT_LOST_TTY;
			client_exitval = 1;
			proc_send(client_peer, MSG_EXITING, -1, NULL, 0);
			break;
		case SIGTERM:
			if (!client_suspended)
				client_exitreason = CLIENT_EXIT_TERMINATED;
			client_exitval = 1;
			proc_send(client_peer, MSG_EXITING, -1, NULL, 0);
			break;
		case SIGWINCH:
			proc_send(client_peer, MSG_RESIZE, -1, NULL, 0);
			break;
		case SIGCONT:
			memset(&sigact, 0, sizeof sigact);
			sigemptyset(&sigact.sa_mask);
			sigact.sa_flags = SA_RESTART;
			sigact.sa_handler = SIG_IGN;
			if (sigaction(SIGTSTP, &sigact, NULL) != 0)
				fatal("sigaction failed");
			proc_send(client_peer, MSG_WAKEUP, -1, NULL, 0);
			client_suspended = 0;
			break;
		}
	}
}

/* Callback for file write error or close. */
static void
client_file_check_cb(__unused struct client *c, __unused const char *path,
    __unused int error, __unused int closed, __unused struct evbuffer *buffer,
    __unused void *data)
{
	if (client_exitflag)
		client_exit();
}

/* Callback for client read events. */
static void
client_dispatch(struct imsg *imsg, __unused void *arg)
{
	if (imsg == NULL) {
		if (!client_exitflag) {
			client_exitreason = CLIENT_EXIT_LOST_SERVER;
			client_exitval = 1;
		}
		proc_exit(client_proc);
		return;
	}

	if (client_attached)
		client_dispatch_attached(imsg);
	else
		client_dispatch_wait(imsg);
}

/* Process an exit message. */
static void
client_dispatch_exit_message(char *data, size_t datalen)
{
	int	retval;

	if (datalen < sizeof retval && datalen != 0)
		fatalx("bad MSG_EXIT size");

	if (datalen >= sizeof retval) {
		memcpy(&retval, data, sizeof retval);
		client_exitval = retval;
	}

	if (datalen > sizeof retval) {
		datalen -= sizeof retval;
		data += sizeof retval;

		client_exitmessage = xmalloc(datalen);
		memcpy(client_exitmessage, data, datalen);
		client_exitmessage[datalen - 1] = '\0';

		client_exitreason = CLIENT_EXIT_MESSAGE_PROVIDED;
	}
}

/* Dispatch imsgs when in wait state (before MSG_READY). */
static void
client_dispatch_wait(struct imsg *imsg)
{
	char		*data;
	ssize_t		 datalen;
	static int	 pledge_applied;

	/*
	 * "sendfd" is no longer required once all of the identify messages
	 * have been sent. We know the server won't send us anything until that
	 * point (because we don't ask it to), so we can drop "sendfd" once we
	 * get the first message from the server.
	 */
	if (!pledge_applied) {
		if (pledge(
		    "stdio rpath wpath cpath unix proc exec tty",
		    NULL) != 0)
			fatal("pledge failed");
		pledge_applied = 1;
	}

	data = imsg->data;
	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;

	switch (imsg->hdr.type) {
	case MSG_EXIT:
	case MSG_SHUTDOWN:
		client_dispatch_exit_message(data, datalen);
		client_exitflag = 1;
		client_exit();
		break;
	case MSG_READY:
		if (datalen != 0)
			fatalx("bad MSG_READY size");

		client_attached = 1;
		proc_send(client_peer, MSG_RESIZE, -1, NULL, 0);
		break;
	case MSG_VERSION:
		if (datalen != 0)
			fatalx("bad MSG_VERSION size");

		fprintf(stderr, "protocol version mismatch "
		    "(client %d, server %u)\n", PROTOCOL_VERSION,
		    imsg->hdr.peerid & 0xff);
		client_exitval = 1;
		proc_exit(client_proc);
		break;
	case MSG_FLAGS:
		if (datalen != sizeof client_flags)
			fatalx("bad MSG_FLAGS string");

		memcpy(&client_flags, data, sizeof client_flags);
		log_debug("new flags are %#llx",
		    (unsigned long long)client_flags);
		break;
	case MSG_SHELL:
		if (datalen == 0 || data[datalen - 1] != '\0')
			fatalx("bad MSG_SHELL string");

		client_exec(data, shell_command);
		/* NOTREACHED */
	case MSG_DETACH:
	case MSG_DETACHKILL:
		proc_send(client_peer, MSG_EXITING, -1, NULL, 0);
		break;
	case MSG_EXITED:
		proc_exit(client_proc);
		break;
	case MSG_READ_OPEN:
		file_read_open(&client_files, client_peer, imsg, 1,
		    !(client_flags & CLIENT_CONTROL), client_file_check_cb,
		    NULL);
		break;
	case MSG_READ_CANCEL:
		file_read_cancel(&client_files, imsg);
		break;
	case MSG_WRITE_OPEN:
		file_write_open(&client_files, client_peer, imsg, 1,
		    !(client_flags & CLIENT_CONTROL), client_file_check_cb,
		    NULL);
		break;
	case MSG_WRITE:
		file_write_data(&client_files, imsg);
		break;
	case MSG_WRITE_CLOSE:
		file_write_close(&client_files, imsg);
		break;
	case MSG_OLDSTDERR:
	case MSG_OLDSTDIN:
	case MSG_OLDSTDOUT:
		fprintf(stderr, "server version is too old for client\n");
		proc_exit(client_proc);
		break;
	}
}

/* Dispatch imsgs in attached state (after MSG_READY). */
static void
client_dispatch_attached(struct imsg *imsg)
{
	struct sigaction	 sigact;
	char			*data;
	ssize_t			 datalen;

	data = imsg->data;
	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;

	switch (imsg->hdr.type) {
	case MSG_FLAGS:
		if (datalen != sizeof client_flags)
			fatalx("bad MSG_FLAGS string");

		memcpy(&client_flags, data, sizeof client_flags);
		log_debug("new flags are %#llx",
		    (unsigned long long)client_flags);
		break;
	case MSG_DETACH:
	case MSG_DETACHKILL:
		if (datalen == 0 || data[datalen - 1] != '\0')
			fatalx("bad MSG_DETACH string");

		client_exitsession = xstrdup(data);
		client_exittype = imsg->hdr.type;
		if (imsg->hdr.type == MSG_DETACHKILL)
			client_exitreason = CLIENT_EXIT_DETACHED_HUP;
		else
			client_exitreason = CLIENT_EXIT_DETACHED;
		proc_send(client_peer, MSG_EXITING, -1, NULL, 0);
		break;
	case MSG_EXEC:
		if (datalen == 0 || data[datalen - 1] != '\0' ||
		    strlen(data) + 1 == (size_t)datalen)
			fatalx("bad MSG_EXEC string");
		client_execcmd = xstrdup(data);
		client_execshell = xstrdup(data + strlen(data) + 1);

		client_exittype = imsg->hdr.type;
		proc_send(client_peer, MSG_EXITING, -1, NULL, 0);
		break;
	case MSG_EXIT:
		client_dispatch_exit_message(data, datalen);
		if (client_exitreason == CLIENT_EXIT_NONE)
			client_exitreason = CLIENT_EXIT_EXITED;
		proc_send(client_peer, MSG_EXITING, -1, NULL, 0);
		break;
	case MSG_EXITED:
		if (datalen != 0)
			fatalx("bad MSG_EXITED size");

		proc_exit(client_proc);
		break;
	case MSG_SHUTDOWN:
		if (datalen != 0)
			fatalx("bad MSG_SHUTDOWN size");

		proc_send(client_peer, MSG_EXITING, -1, NULL, 0);
		client_exitreason = CLIENT_EXIT_SERVER_EXITED;
		client_exitval = 1;
		break;
	case MSG_SUSPEND:
		if (datalen != 0)
			fatalx("bad MSG_SUSPEND size");

		memset(&sigact, 0, sizeof sigact);
		sigemptyset(&sigact.sa_mask);
		sigact.sa_flags = SA_RESTART;
		sigact.sa_handler = SIG_DFL;
		if (sigaction(SIGTSTP, &sigact, NULL) != 0)
			fatal("sigaction failed");
		client_suspended = 1;
		kill(getpid(), SIGTSTP);
		break;
	case MSG_LOCK:
		if (datalen == 0 || data[datalen - 1] != '\0')
			fatalx("bad MSG_LOCK string");

		system(data);
		proc_send(client_peer, MSG_UNLOCK, -1, NULL, 0);
		break;
	}
}