/* $OpenBSD: server.c,v 1.214 2026/07/10 13:38:45 nicm Exp $ */

/*

 * 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 <fcntl.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 uint64_t    server_client_flags;

static int     server_exit;

static struct event  server_ev_accept;

static struct event  server_ev_tidy;

struct cmd_find_state  marked_pane;

static u_int     message_next;

struct message_list  message_log;

time_t       current_time;

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;

  if (wl != NULL)

    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. */

int

server_create_socket(uint64_t 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);

}

/* Tidy up every hour. */

static void

server_tidy_event(__unused int fd, __unused short events, __unused void *data)

{

    struct timeval  tv = { .tv_sec = 3600 };

    uint64_t    t = get_timer();

    format_tidy_jobs();

#ifdef HAVE_MALLOC_TRIM

    malloc_trim(0);

#endif

    log_debug("%s: took %llu milliseconds", __func__,

        (unsigned long long)(get_timer() - t));

    evtimer_add(&server_ev_tidy, &tv);

}

/* Fork new server. */

int

server_start(struct tmuxproc *client, uint64_t flags, struct event_base *base,

    int lockfd, char *lockfile)

{

  int    fd;

  sigset_t   set, oldset;

  struct client *c = NULL;

  char    *cause = NULL;

  struct timeval   tv = { .tv_sec = 3600 };

  sigfillset(&set);

  sigprocmask(SIG_BLOCK, &set, &oldset);

  if (~flags & CLIENT_NOFORK) {

    if (proc_fork_and_daemon(&fd) != 0) {

      sigprocmask(SIG_SETMASK, &oldset, NULL);

      return (fd);

    }

  }

  proc_clear_signals(client, 0);

  server_client_flags = flags;

  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");

  input_key_build();

  utf8_update_width_cache();

  RB_INIT(&windows);

  RB_INIT(&all_window_panes);

  TAILQ_INIT(&clients);

  RB_INIT(&sessions);

  key_bindings_init();

  control_build_events();

  hooks_build_events();

  TAILQ_INIT(&message_log);

  gettimeofday(&start_time, NULL);

#ifdef HAVE_SYSTEMD

  server_fd = systemd_create_socket(flags, &cause);

#else

  server_fd = server_create_socket(flags, &cause);

#endif

  if (server_fd != -1)

    server_update_socket();

  if (~flags & CLIENT_NOFORK)

    c = server_client_create(fd);

  else

    options_set_number(global_options, "exit-empty", 0);

  if (lockfd >= 0) {

    unlink(lockfile);

    free(lockfile);

    close(lockfd);

  }

  if (cause != NULL) {

    if (c != NULL) {

      c->exit_message = cause;

      c->flags |= CLIENT_EXIT;

    } else {

      fprintf(stderr, "%s\n", cause);

      exit(1);

    }

  }

  evtimer_set(&server_ev_tidy, server_tidy_event, NULL);

  evtimer_add(&server_ev_tidy, &tv);

  server_acl_init();

  server_add_accept(0);

  proc_loop(server_proc, server_loop);

  job_kill_all();

  prompt_save_history();

  exit(0);

}

/* Server loop callback. */

static int

server_loop(void)

{

  struct client *c;

  u_int    items;

  current_time = time(NULL);

  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 {

      c->flags |= CLIENT_EXIT;

      c->exit_type = CLIENT_EXIT_SHUTDOWN;

    }

    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;

  struct client   *c;

  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;

  }

  c = server_client_create(newfd);

  if (!server_acl_join(c)) {

    c->exit_message = xstrdup("access not allowed");

    c->flags |= CLIENT_EXIT;

  }

}

/*

 * 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;

        window_pane_wait_finish(wp);

        spawn_editor_finish(wp);

        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);

  }

}