/* $OpenBSD: tmux.c,v 1.225 2026/09/25 13:44:49 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/stat.h>

#include <sys/utsname.h>

#include <errno.h>

#include <fcntl.h>

#include <langinfo.h>

#include <locale.h>

#include <pwd.h>

#include <signal.h>

#include <stdlib.h>

#include <string.h>

#include <time.h>

#include <unistd.h>

#include "tmux.h"

struct options  *global_options;  /* server options */

struct options  *global_s_options;  /* session options */

struct options  *global_w_options;  /* window options */

struct environ  *global_environ;

struct timeval   start_time;

const char  *socket_path;

int    ptm_fd = -1;

const char  *shell_command;

static __dead void   usage(int);

static char   *make_label(const char *, char **);

static int     areshell(const char *);

static const char *getshell(void);

#ifdef ASAN

__attribute__((used)) const char *__asan_default_options(void);

__attribute__((used)) const char *

__asan_default_options(void)

{

  return (

      "abort_on_error=1:"

      "halt_on_error=1:"

      "detect_leaks=0:"

      "detect_stack_use_after_return=1:"

      "strict_string_checks=1:"

      "check_initialization_order=1:"

      "log_path=/tmp/tmux-asan:"

      "log_exe_name=1"

  );

}

#endif

static __dead void

usage(int status)

{

  fprintf(status ? stderr : stdout,

      "usage: %s [-2CDhlNuVv] [-c shell-command] [-f file] [-L socket-name]\n"

      "            [-S socket-path] [-T features] [command [flags]]\n",

      getprogname());

  exit(status);

}

static const char *

getshell(void)

{

  struct passwd *pw;

  const char  *shell;

  shell = getenv("SHELL");

  if (checkshell(shell))

    return (shell);

  pw = getpwuid(getuid());

  if (pw != NULL && checkshell(pw->pw_shell))

    return (pw->pw_shell);

  return (_PATH_BSHELL);

}

int

checkshell(const char *shell)

{

  if (shell == NULL || *shell != '/')

    return (0);

  if (areshell(shell))

    return (0);

  if (access(shell, X_OK) != 0)

    return (0);

  return (1);

}

static int

areshell(const char *shell)

{

  const char  *progname, *ptr;

  if ((ptr = strrchr(shell, '/')) != NULL)

    ptr++;

  else

    ptr = shell;

  progname = getprogname();

  if (*progname == '-')

    progname++;

  if (strcmp(ptr, progname) == 0)

    return (1);

  return (0);

}

static char *

expand_path(const char *path, const char *home)

{

  char      *expanded, *name;

  const char    *end;

  struct environ_entry  *value;

  if (strncmp(path, "~/", 2) == 0) {

    if (home == NULL)

      return (NULL);

    xasprintf(&expanded, "%s%s", home, path + 1);

    return (expanded);

  }

  if (*path == '$') {

    end = strchr(path, '/');

    if (end == NULL)

      name = xstrdup(path + 1);

    else

      name = xstrndup(path + 1, end - path - 1);

    value = environ_find(global_environ, name);

    free(name);

    if (value == NULL)

      return (NULL);

    if (end == NULL)

      end = "";

    xasprintf(&expanded, "%s%s", value->value, end);

    return (expanded);

  }

  return (xstrdup(path));

}

static void

expand_paths(const char *s, char ***paths, u_int *n, int no_realpath)

{

  const char  *home = find_home();

  char    *copy, *next, *tmp, resolved[PATH_MAX], *expanded;

  char    *path;

  u_int    i;

  *paths = NULL;

  *n = 0;

  copy = tmp = xstrdup(s);

  while ((next = strsep(&tmp, ":")) != NULL) {

    expanded = expand_path(next, home);

    if (expanded == NULL) {

      log_debug("%s: invalid path: %s", __func__, next);

      continue;

    }

    if (no_realpath)

      path = expanded;

    else {

      if (realpath(expanded, resolved) == NULL) {

        log_debug("%s: realpath(\"%s\") failed: %s",

            __func__, expanded, strerror(errno));

        free(expanded);

        continue;

      }

      path = xstrdup(resolved);

      free(expanded);

    }

    for (i = 0; i < *n; i++) {

      if (strcmp(path, (*paths)[i]) == 0)

        break;

    }

    if (i != *n) {

      log_debug("%s: duplicate path: %s", __func__, path);

      free(path);

      continue;

    }

    *paths = xreallocarray(*paths, (*n) + 1, sizeof *paths);

    (*paths)[(*n)++] = path;

  }

  free(copy);

}

static int

check_socket_path(const char *path, char **cause)

{

  char  *copy, *next, *tmp;

  if (*path != '/') {

    xasprintf(cause, "socket directory %s is not an absolute path",

        path);

    return (0);

  }

  copy = tmp = xstrdup(path);

  while ((next = strsep(&tmp, "/")) != NULL) {

    if (strcmp(next, "..") == 0) {

      xasprintf(cause, "socket directory %s contains ..",

          path);

      free(copy);

      return (0);

    }

  }

  free(copy);

  return (1);

}

static char *

make_label(const char *label, char **cause)

{

  char    **paths, *path = NULL, *base, resolved[PATH_MAX];

  u_int     i, n;

  struct stat   sb;

  uid_t     uid;

  *cause = NULL;

  if (label == NULL)

    label = "default";

  uid = getuid();

  /*

   * An unset variable has already been dropped and an empty one is

   * skipped, but anything else must be an existing absolute path with no

   * ".." or it is an error.

   */

  expand_paths(TMUX_SOCK, &paths, &n, 1);

  for (i = 0; i < n; i++) {

    if (*paths[i] == '\0')

      continue;

    if (!check_socket_path(paths[i], cause))

      break;

    if (realpath(paths[i], resolved) == NULL) {

      xasprintf(cause,

          "couldn't resolve socket directory %s (%s)",

          paths[i], strerror(errno));

      break;

    }

    path = xstrdup(resolved);

    break;

  }

  for (i = 0; i < n; i++)

    free(paths[i]);

  free(paths);

  if (path == NULL) {

    if (*cause == NULL)

      xasprintf(cause, "no suitable socket path");

    return (NULL);

  }

  xasprintf(&base, "%s/tmux-%ld", path, (long)uid);

  free(path);

  if (mkdir(base, S_IRWXU) != 0 && errno != EEXIST) {

    xasprintf(cause, "couldn't create directory %s (%s)", base,

        strerror(errno));

    goto fail;

  }

  if (lstat(base, &sb) != 0) {

    xasprintf(cause, "couldn't read directory %s (%s)", base,

        strerror(errno));

    goto fail;

  }

  if (!S_ISDIR(sb.st_mode)) {

    xasprintf(cause, "%s is not a directory", base);

    goto fail;

  }

  if (sb.st_uid != uid || (sb.st_mode & TMUX_SOCK_PERM) != 0) {

    xasprintf(cause, "directory %s has unsafe permissions", base);

    goto fail;

  }

  xasprintf(&path, "%s/%s", base, label);

  free(base);

  return (path);

fail:

  free(base);

  return (NULL);

}

char *

shell_argv0(const char *shell, int is_login)

{

  const char  *slash, *name;

  char    *argv0;

  slash = strrchr(shell, '/');

  if (slash != NULL && slash[1] != '\0')

    name = slash + 1;

  else

    name = shell;

  if (is_login)

    xasprintf(&argv0, "-%s", name);

  else

    xasprintf(&argv0, "%s", name);

  return (argv0);

}

void

setblocking(int fd, int state)

{

  int mode;

  if ((mode = fcntl(fd, F_GETFL)) != -1) {

    if (!state)

      mode |= O_NONBLOCK;

    else

      mode &= ~O_NONBLOCK;

    fcntl(fd, F_SETFL, mode);

  }

}

uint64_t

get_timer(void)

{

  struct timespec ts;

  /*

   * We want a timestamp in milliseconds suitable for time measurement,

   * so prefer the monotonic clock.

   */

  if (clock_gettime(CLOCK_MONOTONIC, &ts) != 0)

    clock_gettime(CLOCK_REALTIME, &ts);

  return ((ts.tv_sec * 1000ULL) + (ts.tv_nsec / 1000000ULL));

}

char *

clean_name(const char *name, int untrusted)

{

  char  *copy, *cp, *new_name;

  if (!utf8_isvalid(name))

    return (NULL);

  copy = xstrdup(name);

  for (cp = copy; *cp != '\0'; cp++) {

    if (untrusted && cp[0] == '#' && cp[1] == '(')

      *cp = '_';

  }

  utf8_stravis(&new_name, copy, VIS_OCTAL|VIS_CSTYLE|VIS_TAB|VIS_NL);

  free(copy);

  return (new_name);

}

int

check_name(const char *name)

{

  if (!utf8_isvalid(name))

    return (0);

  return (1);

}

const char *

sig2name(int signo)

{

     static char  s[11];

#ifdef HAVE_SYS_SIGNAME

     if (signo > 0 && signo < NSIG)

       return (sys_signame[signo]);

#endif

     xsnprintf(s, sizeof s, "%d", signo);

     return (s);

}

const char *

find_cwd(void)

{

  char     resolved1[PATH_MAX], resolved2[PATH_MAX];

  static char  cwd[PATH_MAX];

  const char  *pwd;

  if (getcwd(cwd, sizeof cwd) == NULL)

    return (NULL);

  if ((pwd = getenv("PWD")) == NULL || *pwd == '\0')

    return (cwd);

  /*

   * We want to use PWD so that symbolic links are maintained,

   * but only if it matches the actual working directory.

   */

  if (realpath(pwd, resolved1) == NULL)

    return (cwd);

  if (realpath(cwd, resolved2) == NULL)

    return (cwd);

  if (strcmp(resolved1, resolved2) != 0)

    return (cwd);

  return (pwd);

}

const char *

find_home(void)

{

  struct passwd   *pw;

  static const char *home;

  if (home != NULL)

    return (home);

  home = getenv("HOME");

  if (home == NULL || *home == '\0') {

    pw = getpwuid(getuid());

    if (pw != NULL)

      home = xstrdup(pw->pw_dir);

    else

      home = NULL;

  }

  return (home);

}

const char *

getversion(void)

{

  return (TMUX_VERSION);

}

int

main(int argc, char **argv)

{

  char          *path = NULL, *label = NULL;

  char          *cause, **var;

  const char        *s, *cwd;

  int          opt, keys, feat = 0, fflag = 0;

  uint64_t         flags = 0;

  const struct options_table_entry  *oe;

  u_int          i;

  if (setlocale(LC_CTYPE, "en_US.UTF-8") == NULL &&

      setlocale(LC_CTYPE, "C.UTF-8") == NULL) {

    if (setlocale(LC_CTYPE, "") == NULL)

      errx(1, "invalid LC_ALL, LC_CTYPE or LANG");

    s = nl_langinfo(CODESET);

    if (strcasecmp(s, "UTF-8") != 0 && strcasecmp(s, "UTF8") != 0)

      errx(1, "need UTF-8 locale (LC_CTYPE) but have %s", s);

  }

  setlocale(LC_TIME, "");

  tzset();

  if (**argv == '-')

    flags = CLIENT_LOGIN;

  global_environ = environ_create();

  for (var = environ; *var != NULL; var++)

    environ_put(global_environ, *var, 0);

  if ((cwd = find_cwd()) != NULL)

    environ_set(global_environ, "PWD", 0, "%s", cwd);

  expand_paths(TMUX_CONF, &cfg_files, &cfg_nfiles, 1);

  while ((opt = getopt(argc, argv, "2c:CDdf:hlL:NqS:T:uUvV")) != -1) {

    switch (opt) {

    case '2':

      tty_parse_features("256", ":,", &feat, NULL);

      break;

    case 'c':

      shell_command = optarg;

      break;

    case 'D':

      flags |= CLIENT_NOFORK;

      break;

    case 'C':

      if (flags & CLIENT_CONTROL)

        flags |= CLIENT_CONTROLCONTROL;

      else

        flags |= CLIENT_CONTROL;

      break;

    case 'f':

      if (!fflag) {

        fflag = 1;

        for (i = 0; i < cfg_nfiles; i++)

          free(cfg_files[i]);

        cfg_nfiles = 0;

      }

      cfg_files = xreallocarray(cfg_files, cfg_nfiles + 1,

          sizeof *cfg_files);

      cfg_files[cfg_nfiles++] = xstrdup(optarg);

      cfg_quiet = 0;

      break;

    case 'h':

      usage(0);

    case 'V':

      printf("tmux %s\n", getversion());

      exit(0);

    case 'l':

      flags |= CLIENT_LOGIN;

      break;

    case 'L':

      free(label);

      label = xstrdup(optarg);

      break;

    case 'N':

      flags |= CLIENT_NOSTARTSERVER;

      break;

    case 'q':

      break;

    case 'S':

      free(path);

      path = xstrdup(optarg);

      break;

    case 'T':

      tty_parse_features(optarg, ":,", &feat, NULL);

      break;

    case 'u':

      flags |= CLIENT_UTF8;

      break;

    case 'v':

      log_add_level();

      break;

    default:

      usage(1);

    }

  }

  argc -= optind;

  argv += optind;

  if (shell_command != NULL && argc != 0)

    usage(1);

  if ((flags & CLIENT_NOFORK) && argc != 0)

    usage(1);

  if ((ptm_fd = getptmfd()) == -1)

    err(1, "getptmfd");

  if (pledge("stdio rpath wpath cpath flock fattr unix getpw sendfd "

      "recvfd proc exec tty ps", NULL) != 0)

    err(1, "pledge");

  /*

   * tmux is a UTF-8 terminal, so if TMUX is set, assume UTF-8.

   * Otherwise, if the user has set LC_ALL, LC_CTYPE or LANG to contain

   * UTF-8, it is a safe assumption that either they are using a UTF-8

   * terminal, or if not they know that output from UTF-8-capable

   * programs may be wrong.

   */

  if (getenv("TMUX") != NULL)

    flags |= CLIENT_UTF8;

  else {

    s = getenv("LC_ALL");

    if (s == NULL || *s == '\0')

      s = getenv("LC_CTYPE");

    if (s == NULL || *s == '\0')

      s = getenv("LANG");

    if (s == NULL || *s == '\0')

      s = "";

    if (strcasestr(s, "UTF-8") != NULL ||

        strcasestr(s, "UTF8") != NULL)

      flags |= CLIENT_UTF8;

  }

  global_options = options_create(NULL);

  global_s_options = options_create(NULL);

  global_w_options = options_create(NULL);

  for (oe = options_table; oe->name != NULL; oe++) {

    if (oe->scope & OPTIONS_TABLE_SERVER)

      options_default(global_options, oe);

    if (oe->scope & OPTIONS_TABLE_SESSION)

      options_default(global_s_options, oe);

    if (oe->scope & OPTIONS_TABLE_WINDOW)

      options_default(global_w_options, oe);

  }

  /*

   * The default shell comes from SHELL or from the user's passwd entry

   * if available.

   */

  options_set_string(global_s_options, "default-shell", 0, "%s",

      getshell());

  /* Override keys to vi if VISUAL or EDITOR are set. */

  if ((s = getenv("VISUAL")) != NULL || (s = getenv("EDITOR")) != NULL) {

    options_set_string(global_options, "editor", 0, "%s", s);

    if (strrchr(s, '/') != NULL)

      s = strrchr(s, '/') + 1;

    if (strstr(s, "vi") != NULL)

      keys = MODEKEY_VI;

    else

      keys = MODEKEY_EMACS;

    options_set_number(global_s_options, "status-keys", keys);

    options_set_number(global_w_options, "mode-keys", keys);

  }

  /*

   * If socket is specified on the command-line with -S or -L, it is

   * used. Otherwise, $TMUX is checked and if that fails "default" is

   * used.

   */

  if (path == NULL && label == NULL) {

    s = getenv("TMUX");

    if (s != NULL && *s != '\0' && *s != ',') {

      path = xstrdup(s);

      path[strcspn(path, ",")] = '\0';

    }

  }

  if (path == NULL) {

    if ((path = make_label(label, &cause)) == NULL) {

      if (cause != NULL) {

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

        free(cause);

      }

      exit(1);

    }

    flags |= CLIENT_DEFAULTSOCKET;

  }

  socket_path = path;

  free(label);

  /* Pass control to the client. */

  exit(client_main(osdep_event_init(), argc, argv, flags, feat));

}