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GCC Code Coverage Report

Directory:	./		Exec	Total	Coverage
File:	usr.bin/tmux/client.c	Lines:	0	343	0.0 %
Date:	2017-11-13	Branches:	0	212	0.0 %


/* $OpenBSD: client.c,v 1.123 2017/07/14 18:49:07 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/file.h>
#include <sys/socket.h>
#include <sys/stat.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 int		 client_flags;
static struct event	 client_stdin;
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_exitreason = CLIENT_EXIT_NONE;
static int		 client_exitval;
static enum msgtype	 client_exittype;
static const char	*client_exitsession;
static const char	*client_execshell;
static const char	*client_execcmd;
static int		 client_attached;

static __dead void	 client_exec(const char *,const char *);
static int		 client_get_lock(char *);
static int		 client_connect(struct event_base *, const char *, int);
static void		 client_send_identify(const char *, const char *);
static void		 client_stdin_callback(int, short, void *);
static void		 client_write(int, const char *, size_t);
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, int start_server)
{
	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 (!start_server)
			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, 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 ("lost server");
	case CLIENT_EXIT_EXITED:
		return ("exited");
	case CLIENT_EXIT_SERVER_EXITED:
		return ("server exited");
	}
	return ("unknown reason");
}

/* Client main loop. */
int
client_main(struct event_base *base, int argc, char **argv, int flags)
{
	struct cmd		*cmd;
	struct cmd_list		*cmdlist;
	struct msg_command_data	*data;
	int			 cmdflags, fd, i;
	const char		*ttynam, *cwd;
	pid_t			 ppid;
	enum msgtype		 msg;
	char			*cause, path[PATH_MAX];
	struct termios		 tio, saved_tio;
	size_t			 size;

	/* Ignore SIGCHLD now or daemon() in the server will leave a zombie. */
	signal(SIGCHLD, SIG_IGN);

	/* Save the flags. */
	client_flags = flags;

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

		/*
		 * It sucks parsing the command string twice (in client and
		 * later in server) but it is necessary to get the start server
		 * flag.
		 */
		cmdlist = cmd_list_parse(argc, argv, NULL, 0, &cause);
		if (cmdlist != NULL) {
			TAILQ_FOREACH(cmd, &cmdlist->list, qentry) {
				if (cmd->entry->flags & CMD_STARTSERVER)
					cmdflags |= CMD_STARTSERVER;
			}
			cmd_list_free(cmdlist);
		}
	}

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

	/* Initialize the client socket and start the server. */
	fd = client_connect(base, socket_path, cmdflags & CMD_STARTSERVER);
	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 = getcwd(path, sizeof path)) == NULL) {
		if ((cwd = find_home()) == NULL)
			cwd = "/";
	}
	if ((ttynam = ttyname(STDIN_FILENO)) == NULL)
		ttynam = "";

	/*
	 * 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 unix sendfd proc exec tty flock rpath cpath wpath", NULL) != 0)
		fatal("pledge failed");

	/* 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);

	/* Create stdin handler. */
	setblocking(STDIN_FILENO, 0);
	event_set(&client_stdin, STDIN_FILENO, EV_READ|EV_PERSIST,
	    client_stdin_callback, NULL);
	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, cwd);

	/* 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;
		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);
	}

	/* 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_CONTROLCONTROL) {
		if (client_exitreason != CLIENT_EXIT_NONE)
			printf("%%exit %s\n", client_exit_message());
		else
			printf("%%exit\n");
		printf("\033\\");
		tcsetattr(STDOUT_FILENO, TCSAFLUSH, &saved_tio);
	} else if (client_exitreason != CLIENT_EXIT_NONE)
		fprintf(stderr, "%s\n", client_exit_message());
	setblocking(STDIN_FILENO, 1);
	return (client_exitval);
}

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

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

	if ((s = getenv("TERM")) == NULL)
		s = "";
	proc_send(client_peer, MSG_IDENTIFY_TERM, -1, s, strlen(s) + 1);

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

	if ((fd = dup(STDIN_FILENO)) == -1)
		fatal("dup failed");
	proc_send(client_peer, MSG_IDENTIFY_STDIN, 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);
}

/* Callback for client stdin read events. */
static void
client_stdin_callback(__unused int fd, __unused short events,
    __unused void *arg)
{
	struct msg_stdin_data	data;

	data.size = read(STDIN_FILENO, data.data, sizeof data.data);
	if (data.size < 0 && (errno == EINTR || errno == EAGAIN))
		return;

	proc_send(client_peer, MSG_STDIN, -1, &data, sizeof data);
	if (data.size <= 0)
		event_del(&client_stdin);
}

/* Force write to file descriptor. */
static void
client_write(int fd, const char *data, size_t size)
{
	ssize_t	used;

	while (size != 0) {
		used = write(fd, data, size);
		if (used == -1) {
			if (errno == EINTR || errno == EAGAIN)
				continue;
			break;
		}
		data += used;
		size -= used;
	}
}

/* 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;

	if (sig == SIGCHLD)
		waitpid(WAIT_ANY, &status, WNOHANG);
	else if (!client_attached) {
		if (sig == SIGTERM)
			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:
			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);
			break;
		}
	}
}

/* Callback for client read events. */
static void
client_dispatch(struct imsg *imsg, __unused void *arg)
{
	if (imsg == NULL) {
		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);
}

/* Dispatch imsgs when in wait state (before MSG_READY). */
static void
client_dispatch_wait(struct imsg *imsg)
{
	char			*data;
	ssize_t			 datalen;
	struct msg_stdout_data	 stdoutdata;
	struct msg_stderr_data	 stderrdata;
	int			 retval;
	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 unix proc exec tty flock rpath cpath wpath", 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:
		if (datalen != sizeof retval && datalen != 0)
			fatalx("bad MSG_EXIT size");
		if (datalen == sizeof retval) {
			memcpy(&retval, data, sizeof retval);
			client_exitval = retval;
		}
		proc_exit(client_proc);
		break;
	case MSG_READY:
		if (datalen != 0)
			fatalx("bad MSG_READY size");

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

		event_add(&client_stdin, NULL);
		break;
	case MSG_STDOUT:
		if (datalen != sizeof stdoutdata)
			fatalx("bad MSG_STDOUT size");
		memcpy(&stdoutdata, data, sizeof stdoutdata);

		client_write(STDOUT_FILENO, stdoutdata.data,
		    stdoutdata.size);
		break;
	case MSG_STDERR:
		if (datalen != sizeof stderrdata)
			fatalx("bad MSG_STDERR size");
		memcpy(&stderrdata, data, sizeof stderrdata);

		client_write(STDERR_FILENO, stderrdata.data,
		    stderrdata.size);
		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_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;
	}
}

/* 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_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:
		if (datalen != 0 && datalen != sizeof (int))
			fatalx("bad MSG_EXIT size");

		proc_send(client_peer, MSG_EXITING, -1, NULL, 0);
		client_exitreason = CLIENT_EXIT_EXITED;
		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");
		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;
	}
}


Generated by: GCOVR (Version 3.3)

Line	Branch	Exec	Source
1			/* $OpenBSD: client.c,v 1.123 2017/07/14 18:49:07 nicm Exp $ */
2
3			/*
4			* Copyright (c) 2007 Nicholas Marriott <nicholas.marriott@gmail.com>
5			*
6			* Permission to use, copy, modify, and distribute this software for any
7			* purpose with or without fee is hereby granted, provided that the above
8			* copyright notice and this permission notice appear in all copies.
9			*
10			* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11			* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12			* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13			* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14			* WHATSOEVER RESULTING FROM LOSS OF MIND, USE, DATA OR PROFITS, WHETHER
15			* IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
16			* OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17			*/
18
19			#include <sys/types.h>
20			#include <sys/file.h>
21			#include <sys/socket.h>
22			#include <sys/stat.h>
23			#include <sys/un.h>
24			#include <sys/wait.h>
25
26			#include <errno.h>
27			#include <event.h>
28			#include <fcntl.h>
29			#include <imsg.h>
30			#include <signal.h>
31			#include <stdlib.h>
32			#include <string.h>
33			#include <unistd.h>
34
35			#include "tmux.h"
36
37			static struct tmuxproc *client_proc;
38			static struct tmuxpeer *client_peer;
39			static int client_flags;
40			static struct event client_stdin;
41			static enum {
42			CLIENT_EXIT_NONE,
43			CLIENT_EXIT_DETACHED,
44			CLIENT_EXIT_DETACHED_HUP,
45			CLIENT_EXIT_LOST_TTY,
46			CLIENT_EXIT_TERMINATED,
47			CLIENT_EXIT_LOST_SERVER,
48			CLIENT_EXIT_EXITED,
49			CLIENT_EXIT_SERVER_EXITED,
50			} client_exitreason = CLIENT_EXIT_NONE;
51			static int client_exitval;
52			static enum msgtype client_exittype;
53			static const char *client_exitsession;
54			static const char *client_execshell;
55			static const char *client_execcmd;
56			static int client_attached;
57
58			static __dead void client_exec(const char ,const char );
59			static int client_get_lock(char *);
60			static int client_connect(struct event_base , const char , int);
61			static void client_send_identify(const char , const char );
62			static void client_stdin_callback(int, short, void *);
63			static void client_write(int, const char *, size_t);
64			static void client_signal(int);
65			static void client_dispatch(struct imsg , void );
66			static void client_dispatch_attached(struct imsg *);
67			static void client_dispatch_wait(struct imsg *);
68			static const char *client_exit_message(void);
69
70			/*
71			* Get server create lock. If already held then server start is happening in
72			* another client, so block until the lock is released and return -2 to
73			* retry. Return -1 on failure to continue and start the server anyway.
74			*/
75			static int
76			client_get_lock(char *lockfile)
77			{
78			int lockfd;
79
80			log_debug("lock file is %s", lockfile);
81
82			if ((lockfd = open(lockfile, O_WRONLY\|O_CREAT, 0600)) == -1) {
83			log_debug("open failed: %s", strerror(errno));
84			return (-1);
85			}
86
87			if (flock(lockfd, LOCK_EX\|LOCK_NB) == -1) {
88			log_debug("flock failed: %s", strerror(errno));
89			if (errno != EAGAIN)
90			return (lockfd);
91			while (flock(lockfd, LOCK_EX) == -1 && errno == EINTR)
92			/* nothing */;
93			close(lockfd);
94			return (-2);
95			}
96			log_debug("flock succeeded");
97
98			return (lockfd);
99			}
100
101			/* Connect client to server. */
102			static int
103			client_connect(struct event_base base, const char path, int start_server)
104			{
105			struct sockaddr_un sa;
106			size_t size;
107			int fd, lockfd = -1, locked = 0;
108			char *lockfile = NULL;
109
110			memset(&sa, 0, sizeof sa);
111			sa.sun_family = AF_UNIX;
112			size = strlcpy(sa.sun_path, path, sizeof sa.sun_path);
113			if (size >= sizeof sa.sun_path) {
114			errno = ENAMETOOLONG;
115			return (-1);
116			}
117			log_debug("socket is %s", path);
118
119			retry:
120			if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1)
121			return (-1);
122
123			log_debug("trying connect");
124			if (connect(fd, (struct sockaddr *)&sa, sizeof sa) == -1) {
125			log_debug("connect failed: %s", strerror(errno));
126			if (errno != ECONNREFUSED && errno != ENOENT)
127			goto failed;
128			if (!start_server)
129			goto failed;
130			close(fd);
131
132			if (!locked) {
133			xasprintf(&lockfile, "%s.lock", path);
134			if ((lockfd = client_get_lock(lockfile)) < 0) {
135			log_debug("didn't get lock (%d)", lockfd);
136
137			free(lockfile);
138			lockfile = NULL;
139
140			if (lockfd == -2)
141			goto retry;
142			}
143			log_debug("got lock (%d)", lockfd);
144
145			/*
146			* Always retry at least once, even if we got the lock,
147			* because another client could have taken the lock,
148			* started the server and released the lock between our
149			* connect() and flock().
150			*/
151			locked = 1;
152			goto retry;
153			}
154
155			if (lockfd >= 0 && unlink(path) != 0 && errno != ENOENT) {
156			free(lockfile);
157			close(lockfd);
158			return (-1);
159			}
160			fd = server_start(client_proc, base, lockfd, lockfile);
161			}
162
163			if (locked && lockfd >= 0) {
164			free(lockfile);
165			close(lockfd);
166			}
167			setblocking(fd, 0);
168			return (fd);
169
170			failed:
171			if (locked) {
172			free(lockfile);
173			close(lockfd);
174			}
175			close(fd);
176			return (-1);
177			}
178
179			/* Get exit string from reason number. */
180			const char *
181			client_exit_message(void)
182			{
183			static char msg[256];
184
185			switch (client_exitreason) {
186			case CLIENT_EXIT_NONE:
187			break;
188			case CLIENT_EXIT_DETACHED:
189			if (client_exitsession != NULL) {
190			xsnprintf(msg, sizeof msg, "detached "
191			"(from session %s)", client_exitsession);
192			return (msg);
193			}
194			return ("detached");
195			case CLIENT_EXIT_DETACHED_HUP:
196			if (client_exitsession != NULL) {
197			xsnprintf(msg, sizeof msg, "detached and SIGHUP "
198			"(from session %s)", client_exitsession);
199			return (msg);
200			}
201			return ("detached and SIGHUP");
202			case CLIENT_EXIT_LOST_TTY:
203			return ("lost tty");
204			case CLIENT_EXIT_TERMINATED:
205			return ("terminated");
206			case CLIENT_EXIT_LOST_SERVER:
207			return ("lost server");
208			case CLIENT_EXIT_EXITED:
209			return ("exited");
210			case CLIENT_EXIT_SERVER_EXITED:
211			return ("server exited");
212			}
213			return ("unknown reason");
214			}
215
216			/* Client main loop. */
217			int
218			client_main(struct event_base base, int argc, char *argv, int flags)
219			{
220			struct cmd *cmd;
221			struct cmd_list *cmdlist;
222			struct msg_command_data *data;
223			int cmdflags, fd, i;
224			const char ttynam, cwd;
225			pid_t ppid;
226			enum msgtype msg;
227			char *cause, path[PATH_MAX];
228			struct termios tio, saved_tio;
229			size_t size;
230
231			/* Ignore SIGCHLD now or daemon() in the server will leave a zombie. */
232			signal(SIGCHLD, SIG_IGN);
233
234			/* Save the flags. */
235			client_flags = flags;
236
237			/* Set up the initial command. */
238			cmdflags = 0;
239			if (shell_command != NULL) {
240			msg = MSG_SHELL;
241			cmdflags = CMD_STARTSERVER;
242			} else if (argc == 0) {
243			msg = MSG_COMMAND;
244			cmdflags = CMD_STARTSERVER;
245			} else {
246			msg = MSG_COMMAND;
247
248			/*
249			* It sucks parsing the command string twice (in client and
250			* later in server) but it is necessary to get the start server
251			* flag.
252			*/
253			cmdlist = cmd_list_parse(argc, argv, NULL, 0, &cause);
254			if (cmdlist != NULL) {
255			TAILQ_FOREACH(cmd, &cmdlist->list, qentry) {
256			if (cmd->entry->flags & CMD_STARTSERVER)
257			cmdflags \|= CMD_STARTSERVER;
258			}
259			cmd_list_free(cmdlist);
260			}
261			}
262
263			/* Create client process structure (starts logging). */
264			client_proc = proc_start("client");
265			proc_set_signals(client_proc, client_signal);
266
267			/* Initialize the client socket and start the server. */
268			fd = client_connect(base, socket_path, cmdflags & CMD_STARTSERVER);
269			if (fd == -1) {
270			if (errno == ECONNREFUSED) {
271			fprintf(stderr, "no server running on %s\n",
272			socket_path);
273			} else {
274			fprintf(stderr, "error connecting to %s (%s)\n",
275			socket_path, strerror(errno));
276			}
277			return (1);
278			}
279			client_peer = proc_add_peer(client_proc, fd, client_dispatch, NULL);
280
281			/* Save these before pledge(). */
282			if ((cwd = getcwd(path, sizeof path)) == NULL) {
283			if ((cwd = find_home()) == NULL)
284			cwd = "/";
285			}
286			if ((ttynam = ttyname(STDIN_FILENO)) == NULL)
287			ttynam = "";
288
289			/*
290			* Drop privileges for client. "proc exec" is needed for -c and for
291			* locking (which uses system(3)).
292			*
293			* "tty" is needed to restore termios(4) and also for some reason -CC
294			* does not work properly without it (input is not recognised).
295			*
296			* "sendfd" is dropped later in client_dispatch_wait().
297			*/
298			if (pledge("stdio unix sendfd proc exec tty flock rpath cpath wpath", NULL) != 0)
299			fatal("pledge failed");
300
301			/* Free stuff that is not used in the client. */
302			if (ptm_fd != -1)
303			close(ptm_fd);
304			options_free(global_options);
305			options_free(global_s_options);
306			options_free(global_w_options);
307			environ_free(global_environ);
308
309			/* Create stdin handler. */
310			setblocking(STDIN_FILENO, 0);
311			event_set(&client_stdin, STDIN_FILENO, EV_READ\|EV_PERSIST,
312			client_stdin_callback, NULL);
313			if (client_flags & CLIENT_CONTROLCONTROL) {
314			if (tcgetattr(STDIN_FILENO, &saved_tio) != 0) {
315			fprintf(stderr, "tcgetattr failed: %s\n",
316			strerror(errno));
317			return (1);
318			}
319			cfmakeraw(&tio);
320			tio.c_iflag = ICRNL\|IXANY;
321			tio.c_oflag = OPOST\|ONLCR;
322			tio.c_lflag = NOKERNINFO;
323			tio.c_cflag = CREAD\|CS8\|HUPCL;
324			tio.c_cc[VMIN] = 1;
325			tio.c_cc[VTIME] = 0;
326			cfsetispeed(&tio, cfgetispeed(&saved_tio));
327			cfsetospeed(&tio, cfgetospeed(&saved_tio));
328			tcsetattr(STDIN_FILENO, TCSANOW, &tio);
329			}
330
331			/* Send identify messages. */
332			client_send_identify(ttynam, cwd);
333
334			/* Send first command. */
335			if (msg == MSG_COMMAND) {
336			/* How big is the command? */
337			size = 0;
338			for (i = 0; i < argc; i++)
339			size += strlen(argv[i]) + 1;
340			data = xmalloc((sizeof *data) + size);
341
342			/* Prepare command for server. */
343			data->argc = argc;
344			if (cmd_pack_argv(argc, argv, (char *)(data + 1), size) != 0) {
345			fprintf(stderr, "command too long\n");
346			free(data);
347			return (1);
348			}
349			size += sizeof *data;
350
351			/* Send the command. */
352			if (proc_send(client_peer, msg, -1, data, size) != 0) {
353			fprintf(stderr, "failed to send command\n");
354			free(data);
355			return (1);
356			}
357			free(data);
358			} else if (msg == MSG_SHELL)
359			proc_send(client_peer, msg, -1, NULL, 0);
360
361			/* Start main loop. */
362			proc_loop(client_proc, NULL);
363
364			/* Run command if user requested exec, instead of exiting. */
365			if (client_exittype == MSG_EXEC) {
366			if (client_flags & CLIENT_CONTROLCONTROL)
367			tcsetattr(STDOUT_FILENO, TCSAFLUSH, &saved_tio);
368			client_exec(client_execshell, client_execcmd);
369			}
370
371			/* Print the exit message, if any, and exit. */
372			if (client_attached) {
373			if (client_exitreason != CLIENT_EXIT_NONE)
374			printf("[%s]\n", client_exit_message());
375
376			ppid = getppid();
377			if (client_exittype == MSG_DETACHKILL && ppid > 1)
378			kill(ppid, SIGHUP);
379			} else if (client_flags & CLIENT_CONTROLCONTROL) {
380			if (client_exitreason != CLIENT_EXIT_NONE)
381			printf("%%exit %s\n", client_exit_message());
382			else
383			printf("%%exit\n");
384			printf("\033\\");
385			tcsetattr(STDOUT_FILENO, TCSAFLUSH, &saved_tio);
386			} else if (client_exitreason != CLIENT_EXIT_NONE)
387			fprintf(stderr, "%s\n", client_exit_message());
388			setblocking(STDIN_FILENO, 1);
389			return (client_exitval);
390			}
391
392			/* Send identify messages to server. */
393			static void
394			client_send_identify(const char ttynam, const char cwd)
395			{
396			const char *s;
397			char **ss;
398			size_t sslen;
399			int fd, flags = client_flags;
400			pid_t pid;
401
402			proc_send(client_peer, MSG_IDENTIFY_FLAGS, -1, &flags, sizeof flags);
403
404			if ((s = getenv("TERM")) == NULL)
405			s = "";
406			proc_send(client_peer, MSG_IDENTIFY_TERM, -1, s, strlen(s) + 1);
407
408			proc_send(client_peer, MSG_IDENTIFY_TTYNAME, -1, ttynam,
409			strlen(ttynam) + 1);
410			proc_send(client_peer, MSG_IDENTIFY_CWD, -1, cwd, strlen(cwd) + 1);
411
412			if ((fd = dup(STDIN_FILENO)) == -1)
413			fatal("dup failed");
414			proc_send(client_peer, MSG_IDENTIFY_STDIN, fd, NULL, 0);
415
416			pid = getpid();
417			proc_send(client_peer, MSG_IDENTIFY_CLIENTPID, -1, &pid, sizeof pid);
418
419			for (ss = environ; *ss != NULL; ss++) {
420			sslen = strlen(*ss) + 1;
421			if (sslen > MAX_IMSGSIZE - IMSG_HEADER_SIZE)
422			continue;
423			proc_send(client_peer, MSG_IDENTIFY_ENVIRON, -1, *ss, sslen);
424			}
425
426			proc_send(client_peer, MSG_IDENTIFY_DONE, -1, NULL, 0);
427			}
428
429			/* Callback for client stdin read events. */
430			static void
431			client_stdin_callback(__unused int fd, __unused short events,
432			__unused void *arg)
433			{
434			struct msg_stdin_data data;
435
436			data.size = read(STDIN_FILENO, data.data, sizeof data.data);
437			if (data.size < 0 && (errno == EINTR \|\| errno == EAGAIN))
438			return;
439
440			proc_send(client_peer, MSG_STDIN, -1, &data, sizeof data);
441			if (data.size <= 0)
442			event_del(&client_stdin);
443			}
444
445			/* Force write to file descriptor. */
446			static void
447			client_write(int fd, const char *data, size_t size)
448			{
449			ssize_t used;
450
451			while (size != 0) {
452			used = write(fd, data, size);
453			if (used == -1) {
454			if (errno == EINTR \|\| errno == EAGAIN)
455			continue;
456			break;
457			}
458			data += used;
459			size -= used;
460			}
461			}
462
463			/* Run command in shell; used for -c. */
464			static __dead void
465			client_exec(const char shell, const char shellcmd)
466			{
467			const char name, ptr;
468			char *argv0;
469
470			log_debug("shell %s, command %s", shell, shellcmd);
471
472			ptr = strrchr(shell, '/');
473			if (ptr != NULL && *(ptr + 1) != '\0')
474			name = ptr + 1;
475			else
476			name = shell;
477			if (client_flags & CLIENT_LOGIN)
478			xasprintf(&argv0, "-%s", name);
479			else
480			xasprintf(&argv0, "%s", name);
481			setenv("SHELL", shell, 1);
482
483			proc_clear_signals(client_proc, 1);
484
485			setblocking(STDIN_FILENO, 1);
486			setblocking(STDOUT_FILENO, 1);
487			setblocking(STDERR_FILENO, 1);
488			closefrom(STDERR_FILENO + 1);
489
490			execl(shell, argv0, "-c", shellcmd, (char *) NULL);
491			fatal("execl failed");
492			}
493
494			/* Callback to handle signals in the client. */
495			static void
496			client_signal(int sig)
497			{
498			struct sigaction sigact;
499			int status;
500
501			if (sig == SIGCHLD)
502			waitpid(WAIT_ANY, &status, WNOHANG);
503			else if (!client_attached) {
504			if (sig == SIGTERM)
505			proc_exit(client_proc);
506			} else {
507			switch (sig) {
508			case SIGHUP:
509			client_exitreason = CLIENT_EXIT_LOST_TTY;
510			client_exitval = 1;
511			proc_send(client_peer, MSG_EXITING, -1, NULL, 0);
512			break;
513			case SIGTERM:
514			client_exitreason = CLIENT_EXIT_TERMINATED;
515			client_exitval = 1;
516			proc_send(client_peer, MSG_EXITING, -1, NULL, 0);
517			break;
518			case SIGWINCH:
519			proc_send(client_peer, MSG_RESIZE, -1, NULL, 0);
520			break;
521			case SIGCONT:
522			memset(&sigact, 0, sizeof sigact);
523			sigemptyset(&sigact.sa_mask);
524			sigact.sa_flags = SA_RESTART;
525			sigact.sa_handler = SIG_IGN;
526			if (sigaction(SIGTSTP, &sigact, NULL) != 0)
527			fatal("sigaction failed");
528			proc_send(client_peer, MSG_WAKEUP, -1, NULL, 0);
529			break;
530			}
531			}
532			}
533
534			/* Callback for client read events. */
535			static void
536			client_dispatch(struct imsg imsg, __unused void arg)
537			{
538			if (imsg == NULL) {
539			client_exitreason = CLIENT_EXIT_LOST_SERVER;
540			client_exitval = 1;
541			proc_exit(client_proc);
542			return;
543			}
544
545			if (client_attached)
546			client_dispatch_attached(imsg);
547			else
548			client_dispatch_wait(imsg);
549			}
550
551			/* Dispatch imsgs when in wait state (before MSG_READY). */
552			static void
553			client_dispatch_wait(struct imsg *imsg)
554			{
555			char *data;
556			ssize_t datalen;
557			struct msg_stdout_data stdoutdata;
558			struct msg_stderr_data stderrdata;
559			int retval;
560			static int pledge_applied;
561
562			/*
563			* "sendfd" is no longer required once all of the identify messages
564			* have been sent. We know the server won't send us anything until that
565			* point (because we don't ask it to), so we can drop "sendfd" once we
566			* get the first message from the server.
567			*/
568			if (!pledge_applied) {
569			if (pledge("stdio unix proc exec tty flock rpath cpath wpath", NULL) != 0)
570			fatal("pledge failed");
571			pledge_applied = 1;
572			};
573
574			data = imsg->data;
575			datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
576
577			switch (imsg->hdr.type) {
578			case MSG_EXIT:
579			case MSG_SHUTDOWN:
580			if (datalen != sizeof retval && datalen != 0)
581			fatalx("bad MSG_EXIT size");
582			if (datalen == sizeof retval) {
583			memcpy(&retval, data, sizeof retval);
584			client_exitval = retval;
585			}
586			proc_exit(client_proc);
587			break;
588			case MSG_READY:
589			if (datalen != 0)
590			fatalx("bad MSG_READY size");
591
592			event_del(&client_stdin);
593			client_attached = 1;
594			proc_send(client_peer, MSG_RESIZE, -1, NULL, 0);
595			break;
596			case MSG_STDIN:
597			if (datalen != 0)
598			fatalx("bad MSG_STDIN size");
599
600			event_add(&client_stdin, NULL);
601			break;
602			case MSG_STDOUT:
603			if (datalen != sizeof stdoutdata)
604			fatalx("bad MSG_STDOUT size");
605			memcpy(&stdoutdata, data, sizeof stdoutdata);
606
607			client_write(STDOUT_FILENO, stdoutdata.data,
608			stdoutdata.size);
609			break;
610			case MSG_STDERR:
611			if (datalen != sizeof stderrdata)
612			fatalx("bad MSG_STDERR size");
613			memcpy(&stderrdata, data, sizeof stderrdata);
614
615			client_write(STDERR_FILENO, stderrdata.data,
616			stderrdata.size);
617			break;
618			case MSG_VERSION:
619			if (datalen != 0)
620			fatalx("bad MSG_VERSION size");
621
622			fprintf(stderr, "protocol version mismatch "
623			"(client %d, server %u)\n", PROTOCOL_VERSION,
624			imsg->hdr.peerid & 0xff);
625			client_exitval = 1;
626			proc_exit(client_proc);
627			break;
628			case MSG_SHELL:
629			if (datalen == 0 \|\| data[datalen - 1] != '\0')
630			fatalx("bad MSG_SHELL string");
631
632			client_exec(data, shell_command);
633			/* NOTREACHED */
634			case MSG_DETACH:
635			case MSG_DETACHKILL:
636			proc_send(client_peer, MSG_EXITING, -1, NULL, 0);
637			break;
638			case MSG_EXITED:
639			proc_exit(client_proc);
640			break;
641			}
642			}
643
644			/* Dispatch imsgs in attached state (after MSG_READY). */
645			static void
646			client_dispatch_attached(struct imsg *imsg)
647			{
648			struct sigaction sigact;
649			char *data;
650			ssize_t datalen;
651
652			data = imsg->data;
653			datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
654
655			switch (imsg->hdr.type) {
656			case MSG_DETACH:
657			case MSG_DETACHKILL:
658			if (datalen == 0 \|\| data[datalen - 1] != '\0')
659			fatalx("bad MSG_DETACH string");
660
661			client_exitsession = xstrdup(data);
662			client_exittype = imsg->hdr.type;
663			if (imsg->hdr.type == MSG_DETACHKILL)
664			client_exitreason = CLIENT_EXIT_DETACHED_HUP;
665			else
666			client_exitreason = CLIENT_EXIT_DETACHED;
667			proc_send(client_peer, MSG_EXITING, -1, NULL, 0);
668			break;
669			case MSG_EXEC:
670			if (datalen == 0 \|\| data[datalen - 1] != '\0' \|\|
671			strlen(data) + 1 == (size_t)datalen)
672			fatalx("bad MSG_EXEC string");
673			client_execcmd = xstrdup(data);
674			client_execshell = xstrdup(data + strlen(data) + 1);
675
676			client_exittype = imsg->hdr.type;
677			proc_send(client_peer, MSG_EXITING, -1, NULL, 0);
678			break;
679			case MSG_EXIT:
680			if (datalen != 0 && datalen != sizeof (int))
681			fatalx("bad MSG_EXIT size");
682
683			proc_send(client_peer, MSG_EXITING, -1, NULL, 0);
684			client_exitreason = CLIENT_EXIT_EXITED;
685			break;
686			case MSG_EXITED:
687			if (datalen != 0)
688			fatalx("bad MSG_EXITED size");
689
690			proc_exit(client_proc);
691			break;
692			case MSG_SHUTDOWN:
693			if (datalen != 0)
694			fatalx("bad MSG_SHUTDOWN size");
695
696			proc_send(client_peer, MSG_EXITING, -1, NULL, 0);
697			client_exitreason = CLIENT_EXIT_SERVER_EXITED;
698			client_exitval = 1;
699			break;
700			case MSG_SUSPEND:
701			if (datalen != 0)
702			fatalx("bad MSG_SUSPEND size");
703
704			memset(&sigact, 0, sizeof sigact);
705			sigemptyset(&sigact.sa_mask);
706			sigact.sa_flags = SA_RESTART;
707			sigact.sa_handler = SIG_DFL;
708			if (sigaction(SIGTSTP, &sigact, NULL) != 0)
709			fatal("sigaction failed");
710			kill(getpid(), SIGTSTP);
711			break;
712			case MSG_LOCK:
713			if (datalen == 0 \|\| data[datalen - 1] != '\0')
714			fatalx("bad MSG_LOCK string");
715
716			system(data);
717			proc_send(client_peer, MSG_UNLOCK, -1, NULL, 0);
718			break;
719			}
720			}