tmux/server.c

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/* $OpenBSD$ */
/*
* Copyright (c) 2007 Nicholas Marriott <nicm@users.sourceforge.net>
*
* 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 <fcntl.h>
#include <paths.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include <termios.h>
#include <time.h>
#include <unistd.h>
#include "tmux.h"
/*
* Main server functions.
*/
/* Client list. */
struct clients clients;
struct clients dead_clients;
/* Mapping of a pollfd to an fd independent of its position in the array. */
struct poll_item {
int fd;
int events;
void (*fn)(int, int, void *);
void *data;
RB_ENTRY(poll_item) entry;
};
RB_HEAD(poll_items, poll_item) poll_items;
int server_poll_cmp(struct poll_item *, struct poll_item *);
struct poll_item*server_poll_lookup(int);
void server_poll_add(int, int, void (*)(int, int, void *), void *);
struct pollfd *server_poll_flatten(int *);
void server_poll_dispatch(struct pollfd *, int);
void server_poll_reset(void);
RB_PROTOTYPE(poll_items, poll_item, entry, server_poll_cmp);
RB_GENERATE(poll_items, poll_item, entry, server_poll_cmp);
int server_create_socket(void);
void server_callback(int, int, void *);
int server_main(int);
void server_shutdown(void);
int server_should_shutdown(void);
void server_child_signal(void);
void server_fill_windows(void);
void server_fill_clients(void);
void server_fill_jobs(void);
void server_clean_dead(void);
void server_second_timers(void);
void server_lock_server(void);
void server_lock_sessions(void);
int server_update_socket(void);
int
server_poll_cmp(struct poll_item *pitem1, struct poll_item *pitem2)
{
return (pitem1->fd - pitem2->fd);
}
void
server_poll_add(int fd, int events, void (*fn)(int, int, void *), void *data)
{
struct poll_item *pitem;
pitem = xmalloc(sizeof *pitem);
pitem->fd = fd;
pitem->events = events;
pitem->fn = fn;
pitem->data = data;
RB_INSERT(poll_items, &poll_items, pitem);
}
struct poll_item *
server_poll_lookup(int fd)
{
struct poll_item pitem;
pitem.fd = fd;
return (RB_FIND(poll_items, &poll_items, &pitem));
}
struct pollfd *
server_poll_flatten(int *nfds)
{
struct poll_item *pitem;
struct pollfd *pfds;
pfds = NULL;
*nfds = 0;
RB_FOREACH(pitem, poll_items, &poll_items) {
pfds = xrealloc(pfds, (*nfds) + 1, sizeof *pfds);
pfds[*nfds].fd = pitem->fd;
pfds[*nfds].events = pitem->events;
(*nfds)++;
}
return (pfds);
}
void
server_poll_dispatch(struct pollfd *pfds, int nfds)
{
struct poll_item *pitem;
struct pollfd *pfd;
while (nfds > 0) {
pfd = &pfds[--nfds];
if (pfd->revents != 0) {
pitem = server_poll_lookup(pfd->fd);
pitem->fn(pitem->fd, pfd->revents, pitem->data);
}
}
xfree(pfds);
}
void
server_poll_reset(void)
{
struct poll_item *pitem;
while (!RB_EMPTY(&poll_items)) {
pitem = RB_ROOT(&poll_items);
RB_REMOVE(poll_items, &poll_items, pitem);
xfree(pitem);
}
}
/* Create server socket. */
int
server_create_socket(void)
{
struct sockaddr_un sa;
size_t size;
mode_t mask;
int fd, mode;
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;
fatal("socket failed");
}
unlink(sa.sun_path);
if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1)
fatal("socket failed");
mask = umask(S_IXUSR|S_IRWXG|S_IRWXO);
if (bind(fd, (struct sockaddr *) &sa, SUN_LEN(&sa)) == -1)
fatal("bind failed");
umask(mask);
if (listen(fd, 16) == -1)
fatal("listen failed");
if ((mode = fcntl(fd, F_GETFL)) == -1)
fatal("fcntl failed");
if (fcntl(fd, F_SETFL, mode|O_NONBLOCK) == -1)
fatal("fcntl failed");
if (fcntl(fd, F_SETFD, FD_CLOEXEC) == -1)
fatal("fcntl failed");
return (fd);
}
/* Callback for server socket. */
void
server_callback(int fd, int events, unused void *data)
{
struct sockaddr_storage sa;
socklen_t slen = sizeof sa;
int newfd;
if (events & (POLLERR|POLLNVAL|POLLHUP))
fatalx("lost server socket");
if (!(events & POLLIN))
return;
newfd = accept(fd, (struct sockaddr *) &sa, &slen);
if (newfd == -1) {
if (errno == EAGAIN || errno == EINTR || errno == ECONNABORTED)
return;
fatal("accept failed");
}
if (sigterm) {
close(newfd);
return;
}
server_client_create(newfd);
}
/* Fork new server. */
int
server_start(char *path)
{
struct client *c;
int pair[2], srv_fd;
char *cause;
char rpathbuf[MAXPATHLEN];
/* The first client is special and gets a socketpair; create it. */
if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, pair) != 0)
fatal("socketpair failed");
switch (fork()) {
case -1:
fatal("fork failed");
case 0:
break;
default:
close(pair[1]);
return (pair[0]);
}
close(pair[0]);
/*
* Must daemonise before loading configuration as the PID changes so
* $TMUX would be wrong for sessions created in the config file.
*/
if (daemon(1, 0) != 0)
fatal("daemon failed");
logfile("server");
log_debug("server started, pid %ld", (long) getpid());
ARRAY_INIT(&windows);
ARRAY_INIT(&clients);
ARRAY_INIT(&dead_clients);
ARRAY_INIT(&sessions);
ARRAY_INIT(&dead_sessions);
TAILQ_INIT(&session_groups);
mode_key_init_trees();
key_bindings_init();
utf8_build();
start_time = time(NULL);
socket_path = path;
if (realpath(socket_path, rpathbuf) == NULL)
strlcpy(rpathbuf, socket_path, sizeof rpathbuf);
log_debug("socket path %s", socket_path);
setproctitle("server (%s)", rpathbuf);
srv_fd = server_create_socket();
server_client_create(pair[1]);
if (access(SYSTEM_CFG, R_OK) != 0) {
if (errno != ENOENT) {
xasprintf(
&cause, "%s: %s", strerror(errno), SYSTEM_CFG);
goto error;
}
} else if (load_cfg(SYSTEM_CFG, NULL, &cause) != 0)
goto error;
if (cfg_file != NULL && load_cfg(cfg_file, NULL, &cause) != 0)
goto error;
exit(server_main(srv_fd));
error:
/* Write the error and shutdown the server. */
c = ARRAY_FIRST(&clients);
server_write_error(c, cause);
xfree(cause);
sigterm = 1;
server_shutdown();
exit(server_main(srv_fd));
}
/* Main server loop. */
int
server_main(int srv_fd)
{
struct pollfd *pfds;
int nfds, xtimeout;
u_int i;
time_t now, last;
siginit();
log_debug("server socket is %d", srv_fd);
last = time(NULL);
pfds = NULL;
for (;;) {
/* If sigterm, kill all windows and clients. */
if (sigterm)
server_shutdown();
/* Stop if no sessions or clients left. */
if (server_should_shutdown())
break;
/* Handle child exit. */
if (sigchld) {
server_child_signal();
sigchld = 0;
}
/* Recreate socket on SIGUSR1. */
if (sigusr1) {
close(srv_fd);
srv_fd = server_create_socket();
sigusr1 = 0;
}
/* Initialise pollfd array and add server socket. */
server_poll_reset();
server_poll_add(srv_fd, POLLIN, server_callback, NULL);
/* Fill window and client sockets. */
server_fill_jobs();
server_fill_windows();
server_fill_clients();
/* Update socket permissions. */
xtimeout = INFTIM;
if (server_update_socket() != 0)
xtimeout = POLL_TIMEOUT;
/* Do the poll. */
pfds = server_poll_flatten(&nfds);
if (poll(pfds, nfds, xtimeout) == -1) {
if (errno == EAGAIN || errno == EINTR)
continue;
fatal("poll failed");
}
server_poll_dispatch(pfds, nfds);
/* Call second-based timers. */
now = time(NULL);
if (now != last) {
last = now;
server_second_timers();
}
/* Run once-per-loop events. */
server_job_loop();
server_window_loop();
server_client_loop();
/* Collect any unset key bindings. */
key_bindings_clean();
/* Collect dead clients and sessions. */
server_clean_dead();
}
server_poll_reset();
for (i = 0; i < ARRAY_LENGTH(&sessions); i++) {
if (ARRAY_ITEM(&sessions, i) != NULL)
session_destroy(ARRAY_ITEM(&sessions, i));
}
ARRAY_FREE(&sessions);
for (i = 0; i < ARRAY_LENGTH(&clients); i++) {
if (ARRAY_ITEM(&clients, i) != NULL)
server_client_lost(ARRAY_ITEM(&clients, i));
}
ARRAY_FREE(&clients);
mode_key_free_trees();
key_bindings_free();
close(srv_fd);
unlink(socket_path);
xfree(socket_path);
options_free(&global_s_options);
options_free(&global_w_options);
return (0);
}
/* Kill all clients. */
void
server_shutdown(void)
{
struct session *s;
struct client *c;
u_int i, j;
for (i = 0; i < ARRAY_LENGTH(&clients); i++) {
c = ARRAY_ITEM(&clients, i);
if (c != NULL) {
if (c->flags & (CLIENT_BAD|CLIENT_SUSPENDED))
server_client_lost(c);
else
server_write_client(c, MSG_SHUTDOWN, NULL, 0);
}
}
for (i = 0; i < ARRAY_LENGTH(&sessions); i++) {
s = ARRAY_ITEM(&sessions, i);
for (j = 0; j < ARRAY_LENGTH(&clients); j++) {
c = ARRAY_ITEM(&clients, j);
if (c != NULL && c->session == s) {
s = NULL;
break;
}
}
if (s != NULL)
session_destroy(s);
}
}
/* Check if the server should be shutting down (no more clients or windows). */
int
server_should_shutdown(void)
{
u_int i;
for (i = 0; i < ARRAY_LENGTH(&sessions); i++) {
if (ARRAY_ITEM(&sessions, i) != NULL)
return (0);
}
for (i = 0; i < ARRAY_LENGTH(&clients); i++) {
if (ARRAY_ITEM(&clients, i) != NULL)
return (0);
}
return (1);
}
/* Handle SIGCHLD. */
void
server_child_signal(void)
{
struct window *w;
struct window_pane *wp;
struct job *job;
int status;
pid_t pid;
u_int i;
for (;;) {
switch (pid = waitpid(WAIT_ANY, &status, WNOHANG|WUNTRACED)) {
case -1:
if (errno == ECHILD)
return;
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fatal("waitpid failed");
case 0:
return;
}
if (!WIFSTOPPED(status)) {
SLIST_FOREACH(job, &all_jobs, lentry) {
if (pid == job->pid) {
job->pid = -1;
job->status = status;
}
}
continue;
}
if (WSTOPSIG(status) == SIGTTIN || WSTOPSIG(status) == SIGTTOU)
continue;
for (i = 0; i < ARRAY_LENGTH(&windows); i++) {
w = ARRAY_ITEM(&windows, i);
if (w == NULL)
continue;
TAILQ_FOREACH(wp, &w->panes, entry) {
if (wp->pid == pid) {
if (killpg(pid, SIGCONT) != 0)
kill(pid, SIGCONT);
}
}
}
}
}
/* Fill window pollfds. */
void
server_fill_windows(void)
{
struct window *w;
struct window_pane *wp;
u_int i;
int events;
for (i = 0; i < ARRAY_LENGTH(&windows); i++) {
w = ARRAY_ITEM(&windows, i);
if (w == NULL)
continue;
TAILQ_FOREACH(wp, &w->panes, entry) {
if (wp->fd == -1)
continue;
events = POLLIN;
if (BUFFER_USED(wp->out) > 0)
events |= POLLOUT;
server_poll_add(
wp->fd, events, server_window_callback, wp);
if (wp->pipe_fd == -1)
continue;
events = 0;
if (BUFFER_USED(wp->pipe_buf) > 0)
events |= POLLOUT;
server_poll_add(
wp->pipe_fd, events, server_window_callback, wp);
}
}
}
/* Fill client pollfds. */
void
server_fill_clients(void)
{
struct client *c;
u_int i;
int events;
for (i = 0; i < ARRAY_LENGTH(&clients); i++) {
c = ARRAY_ITEM(&clients, i);
if (c != NULL) {
events = 0;
if (!(c->flags & CLIENT_BAD))
events |= POLLIN;
if (c->ibuf.w.queued > 0)
events |= POLLOUT;
server_poll_add(
c->ibuf.fd, events, server_client_callback, c);
}
if (c != NULL && !(c->flags & CLIENT_SUSPENDED) &&
c->tty.fd != -1 && c->session != NULL) {
events = POLLIN;
if (BUFFER_USED(c->tty.out) > 0)
events |= POLLOUT;
server_poll_add(
c->tty.fd, events, server_client_callback, c);
}
}
}
/* Fill in job fds. */
void
server_fill_jobs(void)
{
struct job *job;
SLIST_FOREACH(job, &all_jobs, lentry) {
if (job->fd == -1)
continue;
server_poll_add(job->fd, POLLIN, server_job_callback, job);
}
}
/* Free dead, unreferenced clients and sessions. */
void
server_clean_dead(void)
{
struct session *s;
struct client *c;
u_int i;
for (i = 0; i < ARRAY_LENGTH(&dead_sessions); i++) {
s = ARRAY_ITEM(&dead_sessions, i);
if (s == NULL || s->references != 0)
continue;
ARRAY_SET(&dead_sessions, i, NULL);
xfree(s);
}
for (i = 0; i < ARRAY_LENGTH(&dead_clients); i++) {
c = ARRAY_ITEM(&dead_clients, i);
if (c == NULL || c->references != 0)
continue;
ARRAY_SET(&dead_clients, i, NULL);
xfree(c);
}
}
/* Call any once-per-second timers. */
void
server_second_timers(void)
{
struct window *w;
struct window_pane *wp;
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u_int i;
if (options_get_number(&global_s_options, "lock-server"))
server_lock_server();
else
server_lock_sessions();
for (i = 0; i < ARRAY_LENGTH(&windows); i++) {
w = ARRAY_ITEM(&windows, i);
if (w == NULL)
continue;
TAILQ_FOREACH(wp, &w->panes, entry) {
if (wp->mode != NULL && wp->mode->timer != NULL)
wp->mode->timer(wp);
}
}
}
/* Lock the server if ALL sessions have hit the time limit. */
void
server_lock_server(void)
{
struct session *s;
u_int i;
int timeout;
time_t t;
t = time(NULL);
for (i = 0; i < ARRAY_LENGTH(&sessions); i++) {
if ((s = ARRAY_ITEM(&sessions, i)) == NULL)
continue;
if (s->flags & SESSION_UNATTACHED) {
s->activity = time(NULL);
continue;
}
timeout = options_get_number(&s->options, "lock-after-time");
if (timeout <= 0 || t <= s->activity + timeout)
return; /* not timed out */
}
server_lock();
recalculate_sizes();
}
/* Lock any sessions which have timed out. */
void
server_lock_sessions(void)
{
struct session *s;
u_int i;
int timeout;
time_t t;
t = time(NULL);
for (i = 0; i < ARRAY_LENGTH(&sessions); i++) {
if ((s = ARRAY_ITEM(&sessions, i)) == NULL)
continue;
if (s->flags & SESSION_UNATTACHED) {
s->activity = time(NULL);
continue;
}
timeout = options_get_number(&s->options, "lock-after-time");
if (timeout > 0 && t > s->activity + timeout) {
server_lock_session(s);
recalculate_sizes();
}
}
}
/* Update socket execute permissions based on whether sessions are attached. */
int
server_update_socket(void)
{
struct session *s;
u_int i;
static int last = -1;
int n;
n = 0;
for (i = 0; i < ARRAY_LENGTH(&sessions); i++) {
s = ARRAY_ITEM(&sessions, i);
if (s != NULL && !(s->flags & SESSION_UNATTACHED)) {
n++;
break;
}
}
if (n != last) {
last = n;
if (n != 0)
chmod(socket_path, S_IRWXU);
else
chmod(socket_path, S_IRUSR|S_IWUSR);
}
return (n);
}