Do not continue to send data to suspended/locked clients or there will

[tmux-openbsd.git] / server.c

/* $OpenBSD$ */

/*
 * 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 <event.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;

int              server_fd;
int              server_shutdown;
struct event     server_ev_accept;
struct event     server_ev_second;

struct paste_stack global_buffers;

int              server_create_socket(void);
void             server_loop(void);
int              server_should_shutdown(void);
void             server_send_shutdown(void);
void             server_clean_dead(void);
void             server_accept_callback(int, short, void *);
void             server_signal_callback(int, short, void *);
void             server_child_signal(void);
void             server_child_exited(pid_t, int);
void             server_child_stopped(pid_t, int);
void             server_second_callback(int, short, void *);
void             server_lock_server(void);
void             server_lock_sessions(void);

/* Create server socket. */
int
server_create_socket(void)
{
        struct sockaddr_un      sa;
        size_t                  size;
        mode_t                  mask;
        int                     fd;

        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_IXGRP|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");
        setblocking(fd, 0);

        server_update_socket();

        return (fd);
}

/* Fork new server. */
int
server_start(void)
{
        struct window_pane      *wp;
        int                      pair[2];
        char                    *cause;
        struct timeval           tv;
        u_int                    i;

        /* 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");

        /* event_init() was called in our parent, need to reinit. */
        if (event_reinit(ev_base) != 0)
                fatal("event_reinit failed");
        clear_signals(0);

        logfile("server");
        log_debug("server started, pid %ld", (long) getpid());

        ARRAY_INIT(&windows);
        RB_INIT(&all_window_panes);
        ARRAY_INIT(&clients);
        ARRAY_INIT(&dead_clients);
        RB_INIT(&sessions);
        RB_INIT(&dead_sessions);
        TAILQ_INIT(&session_groups);
        ARRAY_INIT(&global_buffers);
        mode_key_init_trees();
        key_bindings_init();
        utf8_build();

        start_time = time(NULL);
        log_debug("socket path %s", socket_path);
        setproctitle("server (%s)", socket_path);

        server_fd = server_create_socket();
        server_client_create(pair[1]);

        if (access(SYSTEM_CFG, R_OK) == 0)
                load_cfg(SYSTEM_CFG, NULL, &cfg_causes);
        else if (errno != ENOENT) {
                cfg_add_cause(
                    &cfg_causes, "%s: %s", strerror(errno), SYSTEM_CFG);
        }
        if (cfg_file != NULL)
                load_cfg(cfg_file, NULL, &cfg_causes);

        /*
         * If there is a session already, put the current window and pane into
         * more mode.
         */
        if (!RB_EMPTY(&sessions) && !ARRAY_EMPTY(&cfg_causes)) {
                wp = RB_MIN(sessions, &sessions)->curw->window->active;
                window_pane_set_mode(wp, &window_copy_mode);
                window_copy_init_for_output(wp);
                for (i = 0; i < ARRAY_LENGTH(&cfg_causes); i++) {
                        cause = ARRAY_ITEM(&cfg_causes, i);
                        window_copy_add(wp, "%s", cause);
                        xfree(cause);
                }
                ARRAY_FREE(&cfg_causes);
        }
        cfg_finished = 1;

        event_set(&server_ev_accept,
            server_fd, EV_READ|EV_PERSIST, server_accept_callback, NULL);
        event_add(&server_ev_accept, NULL);

        memset(&tv, 0, sizeof tv);
        tv.tv_sec = 1;
        evtimer_set(&server_ev_second, server_second_callback, NULL);
        evtimer_add(&server_ev_second, &tv);

        set_signals(server_signal_callback);
        server_loop();
        exit(0);
}

/* Main server loop. */
void
server_loop(void)
{
        while (!server_should_shutdown()) {
                event_loop(EVLOOP_ONCE);

                server_window_loop();
                server_client_loop();

                key_bindings_clean();
                server_clean_dead();
        }
}

/* Check if the server should be shutting down (no more clients or sessions). */
int
server_should_shutdown(void)
{
        u_int   i;

        if (!options_get_number(&global_options, "exit-unattached")) {
                if (!RB_EMPTY(&sessions))
                        return (0);
        }
        for (i = 0; i < ARRAY_LENGTH(&clients); i++) {
                if (ARRAY_ITEM(&clients, i) != NULL)
                        return (0);
        }
        return (1);
}

/* Shutdown the server by killing all clients and windows. */
void
server_send_shutdown(void)
{
        struct client   *c;
        struct session  *s, *next_s;
        u_int            i;

        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);
                        c->session = NULL;
                }
        }

        s = RB_MIN(sessions, &sessions);
        while (s != NULL) {
                next_s = RB_NEXT(sessions, &sessions, s);
                session_destroy(s);
                s = next_s;
        }
}

/* Free dead, unreferenced clients and sessions. */
void
server_clean_dead(void)
{
        struct session  *s, *next_s;
        struct client   *c;
        u_int            i;

        s = RB_MIN(sessions, &dead_sessions);
        while (s != NULL) {
                next_s = RB_NEXT(sessions, &dead_sessions, s);
                if (s->references == 0) {
                        RB_REMOVE(sessions, &dead_sessions, s);
                        xfree(s->name);
                        xfree(s);
                }
                s = next_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);
        }
}

/* 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->flags & SESSION_UNATTACHED)) {
                        n++;
                        break;
                }
        }

        if (n != last) {
                last = n;

                if (stat(socket_path, &sb) != 0)
                        return;
                mode = sb.st_mode;
                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. */
/* ARGSUSED */
void
server_accept_callback(int fd, short events, unused void *data)
{
        struct sockaddr_storage sa;
        socklen_t               slen = sizeof sa;
        int                     newfd;

        if (!(events & EV_READ))
                return;

        newfd = accept(fd, (struct sockaddr *) &sa, &slen);
        if (newfd == -1) {
                if (errno == EAGAIN || errno == EINTR || errno == ECONNABORTED)
                        return;
                fatal("accept failed");
        }
        if (server_shutdown) {
                close(newfd);
                return;
        }
        server_client_create(newfd);
}

/* Signal handler. */
/* ARGSUSED */
void
server_signal_callback(int sig, unused short events, unused void *data)
{
        switch (sig) {
        case SIGTERM:
                server_shutdown = 1;
                server_send_shutdown();
                break;
        case SIGCHLD:
                server_child_signal();
                break;
        case SIGUSR1:
                event_del(&server_ev_accept);
                close(server_fd);
                server_fd = server_create_socket();
                event_set(&server_ev_accept, server_fd,
                    EV_READ|EV_PERSIST, server_accept_callback, NULL);
                event_add(&server_ev_accept, NULL);
                break;
        }
}

/* Handle SIGCHLD. */
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. */
void
server_child_exited(pid_t pid, int status)
{
        struct window           *w;
        struct window_pane      *wp;
        struct job              *job;
        u_int                    i;

        for (i = 0; i < ARRAY_LENGTH(&windows); i++) {
                if ((w = ARRAY_ITEM(&windows, i)) == NULL)
                        continue;
                TAILQ_FOREACH(wp, &w->panes, entry) {
                        if (wp->pid == pid) {
                                server_destroy_pane(wp);
                                break;
                        }
                }
        }

        LIST_FOREACH(job, &all_jobs, lentry) {
                if (pid == job->pid) {
                        job_died(job, status);  /* might free job */
                        break;
                }
        }
}

/* Handle stopped children. */
void
server_child_stopped(pid_t pid, int status)
{
        struct window           *w;
        struct window_pane      *wp;
        u_int                    i;

        if (WSTOPSIG(status) == SIGTTIN || WSTOPSIG(status) == SIGTTOU)
                return;

        for (i = 0; i < ARRAY_LENGTH(&windows); i++) {
                if ((w = ARRAY_ITEM(&windows, i)) == NULL)
                        continue;
                TAILQ_FOREACH(wp, &w->panes, entry) {
                        if (wp->pid == pid) {
                                if (killpg(pid, SIGCONT) != 0)
                                        kill(pid, SIGCONT);
                        }
                }
        }
}

/* Handle once-per-second timer events. */
/* ARGSUSED */
void
server_second_callback(unused int fd, unused short events, unused void *arg)
{
        struct window           *w;
        struct window_pane      *wp;
        struct timeval           tv;
        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);
                }
        }

        server_client_status_timer();

        evtimer_del(&server_ev_second);
        memset(&tv, 0, sizeof tv);
        tv.tv_sec = 1;
        evtimer_add(&server_ev_second, &tv);
}

/* Lock the server if ALL sessions have hit the time limit. */
void
server_lock_server(void)
{
        struct session  *s;
        int              timeout;
        time_t           t;

        t = time(NULL);
        RB_FOREACH(s, sessions, &sessions) {
                if (s->flags & SESSION_UNATTACHED)
                        continue;
                timeout = options_get_number(&s->options, "lock-after-time");
                if (timeout <= 0 || t <= s->activity_time.tv_sec + timeout)
                        return; /* not timed out */
        }

        server_lock();
        recalculate_sizes();
}

/* Lock any sessions which have timed out. */
void
server_lock_sessions(void)
{
        struct session  *s;
        int              timeout;
        time_t           t;

        t = time(NULL);
        RB_FOREACH(s, sessions, &sessions) {
                if (s->flags & SESSION_UNATTACHED)
                        continue;
                timeout = options_get_number(&s->options, "lock-after-time");
                if (timeout > 0 && t > s->activity_time.tv_sec + timeout) {
                        server_lock_session(s);
                        recalculate_sizes();
                }
        }
}