/* $OpenBSD$ */
/*
* 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 <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 *, const char *);
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(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,
const char *shellcmd)
{
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 (shellcmd != 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", base, 0, 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,
(void *)shellcmd);
/* 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", 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;
#ifdef NOKERNINFO
tio.c_lflag = NOKERNINFO;
#endif
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);
clear_signals(0);
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);
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, 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, arg);
}
/* Dispatch imsgs when in wait state (before MSG_READY). */
static void
client_dispatch_wait(struct imsg *imsg, const char *shellcmd)
{
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", 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");
clear_signals(0);
client_exec(data, shellcmd);
/* 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;
}
}
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