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https://github.com/tmux/tmux.git
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bae2701289
Stop accepting new clients for 1 second on EMFILE/ENFILE. Based on ongoing fixes to other daemons by Theo.
554 lines
12 KiB
C
554 lines
12 KiB
C
/* $Id$ */
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/*
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* Copyright (c) 2007 Nicholas Marriott <nicm@users.sourceforge.net>
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF MIND, USE, DATA OR PROFITS, WHETHER
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* IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
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* OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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#include <sys/types.h>
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#include <sys/ioctl.h>
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#include <sys/socket.h>
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#include <sys/stat.h>
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#include <sys/un.h>
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#include <sys/wait.h>
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#include <errno.h>
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#include <event.h>
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#include <fcntl.h>
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#include <signal.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <syslog.h>
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#include <termios.h>
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#include <time.h>
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#include <unistd.h>
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#include "tmux.h"
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/*
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* Main server functions.
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*/
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/* Client list. */
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struct clients clients;
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struct clients dead_clients;
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int server_fd;
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int server_shutdown;
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struct event server_ev_accept;
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struct event server_ev_second;
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struct paste_stack global_buffers;
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int server_create_socket(void);
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void server_loop(void);
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int server_should_shutdown(void);
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void server_send_shutdown(void);
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void server_clean_dead(void);
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void server_accept_callback(int, short, void *);
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void server_signal_callback(int, short, void *);
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void server_child_signal(void);
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void server_child_exited(pid_t, int);
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void server_child_stopped(pid_t, int);
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void server_second_callback(int, short, void *);
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void server_lock_server(void);
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void server_lock_sessions(void);
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/* Create server socket. */
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int
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server_create_socket(void)
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{
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struct sockaddr_un sa;
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size_t size;
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mode_t mask;
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int fd;
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memset(&sa, 0, sizeof sa);
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sa.sun_family = AF_UNIX;
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size = strlcpy(sa.sun_path, socket_path, sizeof sa.sun_path);
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if (size >= sizeof sa.sun_path) {
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errno = ENAMETOOLONG;
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fatal("socket failed");
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}
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unlink(sa.sun_path);
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if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1)
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fatal("socket failed");
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mask = umask(S_IXUSR|S_IXGRP|S_IRWXO);
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if (bind(fd, (struct sockaddr *) &sa, SUN_LEN(&sa)) == -1)
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fatal("bind failed");
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umask(mask);
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if (listen(fd, 16) == -1)
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fatal("listen failed");
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setblocking(fd, 0);
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server_update_socket();
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return (fd);
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}
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/* Fork new server. */
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int
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server_start(int lockfd, char *lockfile)
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{
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struct window_pane *wp;
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int pair[2];
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char *cause;
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struct timeval tv;
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u_int i;
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/* The first client is special and gets a socketpair; create it. */
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if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, pair) != 0)
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fatal("socketpair failed");
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switch (fork()) {
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case -1:
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fatal("fork failed");
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case 0:
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break;
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default:
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close(pair[1]);
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return (pair[0]);
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}
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close(pair[0]);
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/*
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* Must daemonise before loading configuration as the PID changes so
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* $TMUX would be wrong for sessions created in the config file.
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*/
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if (daemon(1, 0) != 0)
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fatal("daemon failed");
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/* event_init() was called in our parent, need to reinit. */
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if (event_reinit(ev_base) != 0)
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fatal("event_reinit failed");
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clear_signals(0);
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logfile("server");
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log_debug("server started, pid %ld", (long) getpid());
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ARRAY_INIT(&windows);
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RB_INIT(&all_window_panes);
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ARRAY_INIT(&clients);
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ARRAY_INIT(&dead_clients);
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RB_INIT(&sessions);
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RB_INIT(&dead_sessions);
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TAILQ_INIT(&session_groups);
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ARRAY_INIT(&global_buffers);
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mode_key_init_trees();
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key_bindings_init();
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utf8_build();
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start_time = time(NULL);
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log_debug("socket path %s", socket_path);
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#ifdef HAVE_SETPROCTITLE
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setproctitle("server (%s)", socket_path);
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#endif
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server_fd = server_create_socket();
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server_client_create(pair[1]);
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unlink(lockfile);
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xfree(lockfile);
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close(lockfd);
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if (access(SYSTEM_CFG, R_OK) == 0)
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load_cfg(SYSTEM_CFG, NULL, &cfg_causes);
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else if (errno != ENOENT) {
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cfg_add_cause(
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&cfg_causes, "%s: %s", strerror(errno), SYSTEM_CFG);
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}
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if (cfg_file != NULL)
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load_cfg(cfg_file, NULL, &cfg_causes);
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/*
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* If there is a session already, put the current window and pane into
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* more mode.
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*/
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if (!RB_EMPTY(&sessions) && !ARRAY_EMPTY(&cfg_causes)) {
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wp = RB_MIN(sessions, &sessions)->curw->window->active;
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window_pane_set_mode(wp, &window_copy_mode);
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window_copy_init_for_output(wp);
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for (i = 0; i < ARRAY_LENGTH(&cfg_causes); i++) {
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cause = ARRAY_ITEM(&cfg_causes, i);
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window_copy_add(wp, "%s", cause);
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xfree(cause);
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}
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ARRAY_FREE(&cfg_causes);
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}
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cfg_finished = 1;
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server_add_accept(0);
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memset(&tv, 0, sizeof tv);
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tv.tv_sec = 1;
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evtimer_set(&server_ev_second, server_second_callback, NULL);
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evtimer_add(&server_ev_second, &tv);
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set_signals(server_signal_callback);
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server_loop();
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exit(0);
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}
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/* Main server loop. */
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void
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server_loop(void)
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{
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while (!server_should_shutdown()) {
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event_loop(EVLOOP_ONCE);
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server_window_loop();
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server_client_loop();
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key_bindings_clean();
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server_clean_dead();
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}
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}
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/* Check if the server should be shutting down (no more clients or sessions). */
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int
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server_should_shutdown(void)
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{
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u_int i;
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if (!options_get_number(&global_options, "exit-unattached")) {
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if (!RB_EMPTY(&sessions))
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return (0);
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}
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for (i = 0; i < ARRAY_LENGTH(&clients); i++) {
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if (ARRAY_ITEM(&clients, i) != NULL)
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return (0);
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}
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return (1);
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}
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/* Shutdown the server by killing all clients and windows. */
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void
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server_send_shutdown(void)
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{
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struct client *c;
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struct session *s, *next_s;
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u_int i;
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for (i = 0; i < ARRAY_LENGTH(&clients); i++) {
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c = ARRAY_ITEM(&clients, i);
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if (c != NULL) {
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if (c->flags & (CLIENT_BAD|CLIENT_SUSPENDED))
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server_client_lost(c);
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else
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server_write_client(c, MSG_SHUTDOWN, NULL, 0);
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c->session = NULL;
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}
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}
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s = RB_MIN(sessions, &sessions);
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while (s != NULL) {
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next_s = RB_NEXT(sessions, &sessions, s);
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session_destroy(s);
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s = next_s;
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}
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}
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/* Free dead, unreferenced clients and sessions. */
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void
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server_clean_dead(void)
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{
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struct session *s, *next_s;
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struct client *c;
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u_int i;
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s = RB_MIN(sessions, &dead_sessions);
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while (s != NULL) {
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next_s = RB_NEXT(sessions, &dead_sessions, s);
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if (s->references == 0) {
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RB_REMOVE(sessions, &dead_sessions, s);
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xfree(s->name);
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xfree(s);
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}
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s = next_s;
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}
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for (i = 0; i < ARRAY_LENGTH(&dead_clients); i++) {
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c = ARRAY_ITEM(&dead_clients, i);
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if (c == NULL || c->references != 0)
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continue;
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ARRAY_SET(&dead_clients, i, NULL);
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xfree(c);
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}
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}
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/* Update socket execute permissions based on whether sessions are attached. */
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void
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server_update_socket(void)
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{
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struct session *s;
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static int last = -1;
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int n, mode;
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struct stat sb;
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n = 0;
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RB_FOREACH(s, sessions, &sessions) {
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if (!(s->flags & SESSION_UNATTACHED)) {
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n++;
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break;
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}
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}
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if (n != last) {
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last = n;
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if (stat(socket_path, &sb) != 0)
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return;
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mode = sb.st_mode;
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if (n != 0) {
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if (mode & S_IRUSR)
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mode |= S_IXUSR;
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if (mode & S_IRGRP)
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mode |= S_IXGRP;
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if (mode & S_IROTH)
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mode |= S_IXOTH;
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} else
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mode &= ~(S_IXUSR|S_IXGRP|S_IXOTH);
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chmod(socket_path, mode);
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}
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}
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/* Callback for server socket. */
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/* ARGSUSED */
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void
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server_accept_callback(int fd, short events, unused void *data)
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{
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struct sockaddr_storage sa;
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socklen_t slen = sizeof sa;
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int newfd;
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server_add_accept(0);
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if (!(events & EV_READ))
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return;
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newfd = accept(fd, (struct sockaddr *) &sa, &slen);
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if (newfd == -1) {
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if (errno == EAGAIN || errno == EINTR || errno == ECONNABORTED)
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return;
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if (errno == ENFILE || errno == EMFILE) {
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/* Delete and don't try again for 1 second. */
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server_add_accept(1);
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return;
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}
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fatal("accept failed");
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}
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if (server_shutdown) {
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close(newfd);
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return;
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}
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server_client_create(newfd);
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}
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/*
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* Add accept event. If timeout is nonzero, add as a timeout instead of a read
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* event - used to backoff when running out of file descriptors.
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*/
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void
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server_add_accept(int timeout)
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{
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struct timeval tv = { timeout, 0 };
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if (event_initialized(&server_ev_accept))
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event_del(&server_ev_accept);
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if (timeout == 0) {
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event_set(&server_ev_accept,
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server_fd, EV_READ, server_accept_callback, NULL);
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event_add(&server_ev_accept, NULL);
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} else {
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event_set(&server_ev_accept,
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server_fd, EV_TIMEOUT, server_accept_callback, NULL);
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event_add(&server_ev_accept, &tv);
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}
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}
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/* Signal handler. */
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/* ARGSUSED */
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void
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server_signal_callback(int sig, unused short events, unused void *data)
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{
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switch (sig) {
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case SIGTERM:
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server_shutdown = 1;
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server_send_shutdown();
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break;
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case SIGCHLD:
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server_child_signal();
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break;
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case SIGUSR1:
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event_del(&server_ev_accept);
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close(server_fd);
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server_fd = server_create_socket();
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server_add_accept(0);
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break;
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}
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}
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/* Handle SIGCHLD. */
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void
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server_child_signal(void)
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{
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int status;
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pid_t pid;
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for (;;) {
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switch (pid = waitpid(WAIT_ANY, &status, WNOHANG|WUNTRACED)) {
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case -1:
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if (errno == ECHILD)
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return;
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fatal("waitpid failed");
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case 0:
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return;
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}
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if (WIFSTOPPED(status))
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server_child_stopped(pid, status);
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else if (WIFEXITED(status) || WIFSIGNALED(status))
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server_child_exited(pid, status);
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}
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}
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/* Handle exited children. */
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void
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server_child_exited(pid_t pid, int status)
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{
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struct window *w;
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struct window_pane *wp;
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struct job *job;
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u_int i;
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for (i = 0; i < ARRAY_LENGTH(&windows); i++) {
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if ((w = ARRAY_ITEM(&windows, i)) == NULL)
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continue;
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TAILQ_FOREACH(wp, &w->panes, entry) {
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if (wp->pid == pid) {
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server_destroy_pane(wp);
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break;
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}
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}
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}
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LIST_FOREACH(job, &all_jobs, lentry) {
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if (pid == job->pid) {
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job_died(job, status); /* might free job */
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break;
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}
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}
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}
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/* Handle stopped children. */
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void
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server_child_stopped(pid_t pid, int status)
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{
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struct window *w;
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struct window_pane *wp;
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u_int i;
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if (WSTOPSIG(status) == SIGTTIN || WSTOPSIG(status) == SIGTTOU)
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return;
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for (i = 0; i < ARRAY_LENGTH(&windows); i++) {
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if ((w = ARRAY_ITEM(&windows, i)) == NULL)
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continue;
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TAILQ_FOREACH(wp, &w->panes, entry) {
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if (wp->pid == pid) {
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if (killpg(pid, SIGCONT) != 0)
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kill(pid, SIGCONT);
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}
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}
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}
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}
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/* Handle once-per-second timer events. */
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/* ARGSUSED */
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void
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server_second_callback(unused int fd, unused short events, unused void *arg)
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{
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struct window *w;
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struct window_pane *wp;
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struct timeval tv;
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u_int i;
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if (options_get_number(&global_s_options, "lock-server"))
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server_lock_server();
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else
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server_lock_sessions();
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for (i = 0; i < ARRAY_LENGTH(&windows); i++) {
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w = ARRAY_ITEM(&windows, i);
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if (w == NULL)
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continue;
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TAILQ_FOREACH(wp, &w->panes, entry) {
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if (wp->mode != NULL && wp->mode->timer != NULL)
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wp->mode->timer(wp);
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}
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}
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server_client_status_timer();
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evtimer_del(&server_ev_second);
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memset(&tv, 0, sizeof tv);
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tv.tv_sec = 1;
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evtimer_add(&server_ev_second, &tv);
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}
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/* Lock the server if ALL sessions have hit the time limit. */
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void
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server_lock_server(void)
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{
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struct session *s;
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int timeout;
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time_t t;
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t = time(NULL);
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RB_FOREACH(s, sessions, &sessions) {
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if (s->flags & SESSION_UNATTACHED)
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continue;
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timeout = options_get_number(&s->options, "lock-after-time");
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if (timeout <= 0 || t <= s->activity_time.tv_sec + timeout)
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return; /* not timed out */
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}
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server_lock();
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recalculate_sizes();
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}
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/* Lock any sessions which have timed out. */
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void
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server_lock_sessions(void)
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{
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struct session *s;
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int timeout;
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time_t t;
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t = time(NULL);
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RB_FOREACH(s, sessions, &sessions) {
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if (s->flags & SESSION_UNATTACHED)
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continue;
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timeout = options_get_number(&s->options, "lock-after-time");
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if (timeout > 0 && t > s->activity_time.tv_sec + timeout) {
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server_lock_session(s);
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recalculate_sizes();
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}
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}
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}
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