tmux/server.c
nicm dceb6a15d0 Add a -D flag to ask tmux not to daemonize, useful both for running a
debugger (lldb does not have follow-fork-mode) and for running with a
managed supervisor init system. GitHub issue 2190.
2020-05-16 16:07:55 +00:00

531 lines
11 KiB
C

/* $OpenBSD$ */
/*
* 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/ioctl.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 <paths.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <termios.h>
#include <time.h>
#include <unistd.h>
#include "tmux.h"
/*
* Main server functions.
*/
struct clients clients;
struct tmuxproc *server_proc;
static int server_fd = -1;
static int server_client_flags;
static int server_exit;
static struct event server_ev_accept;
struct cmd_find_state marked_pane;
static u_int message_next;
struct message_list message_log;
static int server_loop(void);
static void server_send_exit(void);
static void server_accept(int, short, void *);
static void server_signal(int);
static void server_child_signal(void);
static void server_child_exited(pid_t, int);
static void server_child_stopped(pid_t, int);
/* Set marked pane. */
void
server_set_marked(struct session *s, struct winlink *wl, struct window_pane *wp)
{
cmd_find_clear_state(&marked_pane, 0);
marked_pane.s = s;
marked_pane.wl = wl;
marked_pane.w = wl->window;
marked_pane.wp = wp;
}
/* Clear marked pane. */
void
server_clear_marked(void)
{
cmd_find_clear_state(&marked_pane, 0);
}
/* Is this the marked pane? */
int
server_is_marked(struct session *s, struct winlink *wl, struct window_pane *wp)
{
if (s == NULL || wl == NULL || wp == NULL)
return (0);
if (marked_pane.s != s || marked_pane.wl != wl)
return (0);
if (marked_pane.wp != wp)
return (0);
return (server_check_marked());
}
/* Check if the marked pane is still valid. */
int
server_check_marked(void)
{
return (cmd_find_valid_state(&marked_pane));
}
/* Create server socket. */
static int
server_create_socket(int flags, char **cause)
{
struct sockaddr_un sa;
size_t size;
mode_t mask;
int fd, saved_errno;
memset(&sa, 0, sizeof sa);
sa.sun_family = AF_UNIX;
size = strlcpy(sa.sun_path, socket_path, sizeof sa.sun_path);
if (size >= sizeof sa.sun_path) {
errno = ENAMETOOLONG;
goto fail;
}
unlink(sa.sun_path);
if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1)
goto fail;
if (flags & CLIENT_DEFAULTSOCKET)
mask = umask(S_IXUSR|S_IXGRP|S_IRWXO);
else
mask = umask(S_IXUSR|S_IRWXG|S_IRWXO);
if (bind(fd, (struct sockaddr *)&sa, sizeof sa) == -1) {
saved_errno = errno;
close(fd);
errno = saved_errno;
goto fail;
}
umask(mask);
if (listen(fd, 128) == -1) {
saved_errno = errno;
close(fd);
errno = saved_errno;
goto fail;
}
setblocking(fd, 0);
return (fd);
fail:
if (cause != NULL) {
xasprintf(cause, "error creating %s (%s)", socket_path,
strerror(errno));
}
return (-1);
}
/* Fork new server. */
int
server_start(struct tmuxproc *client, int flags, struct event_base *base,
int lockfd, char *lockfile)
{
int pair[2];
sigset_t set, oldset;
struct client *c;
char *cause = NULL;
sigfillset(&set);
sigprocmask(SIG_BLOCK, &set, &oldset);
if (~flags & CLIENT_NOFORK) {
if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, pair) != 0)
fatal("socketpair failed");
switch (fork()) {
case -1:
fatal("fork failed");
case 0:
break;
default:
sigprocmask(SIG_SETMASK, &oldset, NULL);
close(pair[1]);
return (pair[0]);
}
close(pair[0]);
if (daemon(1, 0) != 0)
fatal("daemon failed");
}
server_client_flags = flags;
proc_clear_signals(client, 0);
if (event_reinit(base) != 0)
fatalx("event_reinit failed");
server_proc = proc_start("server");
proc_set_signals(server_proc, server_signal);
sigprocmask(SIG_SETMASK, &oldset, NULL);
if (log_get_level() > 1)
tty_create_log();
if (pledge("stdio rpath wpath cpath fattr unix getpw recvfd proc exec "
"tty ps", NULL) != 0)
fatal("pledge failed");
RB_INIT(&windows);
RB_INIT(&all_window_panes);
TAILQ_INIT(&clients);
RB_INIT(&sessions);
key_bindings_init();
TAILQ_INIT(&message_log);
gettimeofday(&start_time, NULL);
server_fd = server_create_socket(flags, &cause);
if (server_fd != -1)
server_update_socket();
if (~flags & CLIENT_NOFORK)
c = server_client_create(pair[1]);
else
options_set_number(global_options, "exit-empty", 0);
if (lockfd >= 0) {
unlink(lockfile);
free(lockfile);
close(lockfd);
}
if (cause != NULL) {
cmdq_append(c, cmdq_get_error(cause));
free(cause);
c->flags |= CLIENT_EXIT;
}
server_add_accept(0);
proc_loop(server_proc, server_loop);
job_kill_all();
status_prompt_save_history();
exit(0);
}
/* Server loop callback. */
static int
server_loop(void)
{
struct client *c;
u_int items;
do {
items = cmdq_next(NULL);
TAILQ_FOREACH(c, &clients, entry) {
if (c->flags & CLIENT_IDENTIFIED)
items += cmdq_next(c);
}
} while (items != 0);
server_client_loop();
if (!options_get_number(global_options, "exit-empty") && !server_exit)
return (0);
if (!options_get_number(global_options, "exit-unattached")) {
if (!RB_EMPTY(&sessions))
return (0);
}
TAILQ_FOREACH(c, &clients, entry) {
if (c->session != NULL)
return (0);
}
/*
* No attached clients therefore want to exit - flush any waiting
* clients but don't actually exit until they've gone.
*/
cmd_wait_for_flush();
if (!TAILQ_EMPTY(&clients))
return (0);
if (job_still_running())
return (0);
return (1);
}
/* Exit the server by killing all clients and windows. */
static void
server_send_exit(void)
{
struct client *c, *c1;
struct session *s, *s1;
cmd_wait_for_flush();
TAILQ_FOREACH_SAFE(c, &clients, entry, c1) {
if (c->flags & CLIENT_SUSPENDED)
server_client_lost(c);
else {
if (c->flags & CLIENT_ATTACHED)
notify_client("client-detached", c);
proc_send(c->peer, MSG_SHUTDOWN, -1, NULL, 0);
}
c->session = NULL;
}
RB_FOREACH_SAFE(s, sessions, &sessions, s1)
session_destroy(s, 1, __func__);
}
/* Update socket execute permissions based on whether sessions are attached. */
void
server_update_socket(void)
{
struct session *s;
static int last = -1;
int n, mode;
struct stat sb;
n = 0;
RB_FOREACH(s, sessions, &sessions) {
if (s->attached != 0) {
n++;
break;
}
}
if (n != last) {
last = n;
if (stat(socket_path, &sb) != 0)
return;
mode = sb.st_mode & ACCESSPERMS;
if (n != 0) {
if (mode & S_IRUSR)
mode |= S_IXUSR;
if (mode & S_IRGRP)
mode |= S_IXGRP;
if (mode & S_IROTH)
mode |= S_IXOTH;
} else
mode &= ~(S_IXUSR|S_IXGRP|S_IXOTH);
chmod(socket_path, mode);
}
}
/* Callback for server socket. */
static void
server_accept(int fd, short events, __unused void *data)
{
struct sockaddr_storage sa;
socklen_t slen = sizeof sa;
int newfd;
server_add_accept(0);
if (!(events & EV_READ))
return;
newfd = accept(fd, (struct sockaddr *) &sa, &slen);
if (newfd == -1) {
if (errno == EAGAIN || errno == EINTR || errno == ECONNABORTED)
return;
if (errno == ENFILE || errno == EMFILE) {
/* Delete and don't try again for 1 second. */
server_add_accept(1);
return;
}
fatal("accept failed");
}
if (server_exit) {
close(newfd);
return;
}
server_client_create(newfd);
}
/*
* Add accept event. If timeout is nonzero, add as a timeout instead of a read
* event - used to backoff when running out of file descriptors.
*/
void
server_add_accept(int timeout)
{
struct timeval tv = { timeout, 0 };
if (server_fd == -1)
return;
if (event_initialized(&server_ev_accept))
event_del(&server_ev_accept);
if (timeout == 0) {
event_set(&server_ev_accept, server_fd, EV_READ, server_accept,
NULL);
event_add(&server_ev_accept, NULL);
} else {
event_set(&server_ev_accept, server_fd, EV_TIMEOUT,
server_accept, NULL);
event_add(&server_ev_accept, &tv);
}
}
/* Signal handler. */
static void
server_signal(int sig)
{
int fd;
log_debug("%s: %s", __func__, strsignal(sig));
switch (sig) {
case SIGINT:
case SIGTERM:
server_exit = 1;
server_send_exit();
break;
case SIGCHLD:
server_child_signal();
break;
case SIGUSR1:
event_del(&server_ev_accept);
fd = server_create_socket(server_client_flags, NULL);
if (fd != -1) {
close(server_fd);
server_fd = fd;
server_update_socket();
}
server_add_accept(0);
break;
case SIGUSR2:
proc_toggle_log(server_proc);
break;
}
}
/* Handle SIGCHLD. */
static void
server_child_signal(void)
{
int status;
pid_t pid;
for (;;) {
switch (pid = waitpid(WAIT_ANY, &status, WNOHANG|WUNTRACED)) {
case -1:
if (errno == ECHILD)
return;
fatal("waitpid failed");
case 0:
return;
}
if (WIFSTOPPED(status))
server_child_stopped(pid, status);
else if (WIFEXITED(status) || WIFSIGNALED(status))
server_child_exited(pid, status);
}
}
/* Handle exited children. */
static void
server_child_exited(pid_t pid, int status)
{
struct window *w, *w1;
struct window_pane *wp;
RB_FOREACH_SAFE(w, windows, &windows, w1) {
TAILQ_FOREACH(wp, &w->panes, entry) {
if (wp->pid == pid) {
wp->status = status;
wp->flags |= PANE_STATUSREADY;
log_debug("%%%u exited", wp->id);
wp->flags |= PANE_EXITED;
if (window_pane_destroy_ready(wp))
server_destroy_pane(wp, 1);
break;
}
}
}
job_check_died(pid, status);
}
/* Handle stopped children. */
static void
server_child_stopped(pid_t pid, int status)
{
struct window *w;
struct window_pane *wp;
if (WSTOPSIG(status) == SIGTTIN || WSTOPSIG(status) == SIGTTOU)
return;
RB_FOREACH(w, windows, &windows) {
TAILQ_FOREACH(wp, &w->panes, entry) {
if (wp->pid == pid) {
if (killpg(pid, SIGCONT) != 0)
kill(pid, SIGCONT);
}
}
}
job_check_died(pid, status);
}
/* Add to message log. */
void
server_add_message(const char *fmt, ...)
{
struct message_entry *msg, *msg1;
char *s;
va_list ap;
u_int limit;
va_start(ap, fmt);
xvasprintf(&s, fmt, ap);
va_end(ap);
log_debug("message: %s", s);
msg = xcalloc(1, sizeof *msg);
gettimeofday(&msg->msg_time, NULL);
msg->msg_num = message_next++;
msg->msg = s;
TAILQ_INSERT_TAIL(&message_log, msg, entry);
limit = options_get_number(global_options, "message-limit");
TAILQ_FOREACH_SAFE(msg, &message_log, entry, msg1) {
if (msg->msg_num + limit >= message_next)
break;
free(msg->msg);
TAILQ_REMOVE(&message_log, msg, entry);
free(msg);
}
}