1 /* $OpenBSD$ */ 2 3 /* 4 * Copyright (c) 2019 Nicholas Marriott <nicholas.marriott@gmail.com> 5 * 6 * Permission to use, copy, modify, and distribute this software for any 7 * purpose with or without fee is hereby granted, provided that the above 8 * copyright notice and this permission notice appear in all copies. 9 * 10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 14 * WHATSOEVER RESULTING FROM LOSS OF MIND, USE, DATA OR PROFITS, WHETHER 15 * IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING 16 * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 17 */ 18 19 #include <sys/types.h> 20 21 #include <errno.h> 22 #include <signal.h> 23 #include <stdlib.h> 24 #include <string.h> 25 #include <unistd.h> 26 27 #include "tmux.h" 28 29 /* 30 * Set up the environment and create a new window and pane or a new pane. 31 * 32 * We need to set up the following items: 33 * 34 * - history limit, comes from the session; 35 * 36 * - base index, comes from the session; 37 * 38 * - current working directory, may be specified - if it isn't it comes from 39 * either the client or the session; 40 * 41 * - PATH variable, comes from the client if any, otherwise from the session 42 * environment; 43 * 44 * - shell, comes from default-shell; 45 * 46 * - termios, comes from the session; 47 * 48 * - remaining environment, comes from the session. 49 */ 50 51 static void 52 spawn_log(const char *from, struct spawn_context *sc) 53 { 54 struct session *s = sc->s; 55 struct winlink *wl = sc->wl; 56 struct window_pane *wp0 = sc->wp0; 57 const char *name = cmdq_get_name(sc->item); 58 char tmp[128]; 59 60 log_debug("%s: %s, flags=%#x", from, name, sc->flags); 61 62 if (wl != NULL && wp0 != NULL) 63 xsnprintf(tmp, sizeof tmp, "wl=%d wp0=%%%u", wl->idx, wp0->id); 64 else if (wl != NULL) 65 xsnprintf(tmp, sizeof tmp, "wl=%d wp0=none", wl->idx); 66 else if (wp0 != NULL) 67 xsnprintf(tmp, sizeof tmp, "wl=none wp0=%%%u", wp0->id); 68 else 69 xsnprintf(tmp, sizeof tmp, "wl=none wp0=none"); 70 log_debug("%s: s=$%u %s idx=%d", from, s->id, tmp, sc->idx); 71 log_debug("%s: name=%s", from, sc->name == NULL ? "none" : sc->name); 72 } 73 74 struct winlink * 75 spawn_window(struct spawn_context *sc, char **cause) 76 { 77 struct cmdq_item *item = sc->item; 78 struct client *c = cmdq_get_client(item); 79 struct session *s = sc->s; 80 struct window *w; 81 struct window_pane *wp; 82 struct winlink *wl; 83 int idx = sc->idx; 84 u_int sx, sy, xpixel, ypixel; 85 86 spawn_log(__func__, sc); 87 88 /* 89 * If the window already exists, we are respawning, so destroy all the 90 * panes except one. 91 */ 92 if (sc->flags & SPAWN_RESPAWN) { 93 w = sc->wl->window; 94 if (~sc->flags & SPAWN_KILL) { 95 TAILQ_FOREACH(wp, &w->panes, entry) { 96 if (wp->fd != -1) 97 break; 98 } 99 if (wp != NULL) { 100 xasprintf(cause, "window %s:%d still active", 101 s->name, sc->wl->idx); 102 return (NULL); 103 } 104 } 105 106 sc->wp0 = TAILQ_FIRST(&w->panes); 107 TAILQ_REMOVE(&w->panes, sc->wp0, entry); 108 109 layout_free(w); 110 window_destroy_panes(w); 111 112 TAILQ_INSERT_HEAD(&w->panes, sc->wp0, entry); 113 window_pane_resize(sc->wp0, w->sx, w->sy); 114 115 layout_init(w, sc->wp0); 116 w->active = NULL; 117 window_set_active_pane(w, sc->wp0, 0); 118 } 119 120 /* 121 * Otherwise we have no window so we will need to create one. First 122 * check if the given index already exists and destroy it if so. 123 */ 124 if ((~sc->flags & SPAWN_RESPAWN) && idx != -1) { 125 wl = winlink_find_by_index(&s->windows, idx); 126 if (wl != NULL && (~sc->flags & SPAWN_KILL)) { 127 xasprintf(cause, "index %d in use", idx); 128 return (NULL); 129 } 130 if (wl != NULL) { 131 /* 132 * Can't use session_detach as it will destroy session 133 * if this makes it empty. 134 */ 135 wl->flags &= ~WINLINK_ALERTFLAGS; 136 notify_session_window("window-unlinked", s, wl->window); 137 winlink_stack_remove(&s->lastw, wl); 138 winlink_remove(&s->windows, wl); 139 140 if (s->curw == wl) { 141 s->curw = NULL; 142 sc->flags &= ~SPAWN_DETACHED; 143 } 144 } 145 } 146 147 /* Then create a window if needed. */ 148 if (~sc->flags & SPAWN_RESPAWN) { 149 if (idx == -1) 150 idx = -1 - options_get_number(s->options, "base-index"); 151 if ((sc->wl = winlink_add(&s->windows, idx)) == NULL) { 152 xasprintf(cause, "couldn't add window %d", idx); 153 return (NULL); 154 } 155 default_window_size(sc->tc, s, NULL, &sx, &sy, &xpixel, &ypixel, 156 -1); 157 if ((w = window_create(sx, sy, xpixel, ypixel)) == NULL) { 158 winlink_remove(&s->windows, sc->wl); 159 xasprintf(cause, "couldn't create window %d", idx); 160 return (NULL); 161 } 162 if (s->curw == NULL) 163 s->curw = sc->wl; 164 sc->wl->session = s; 165 w->latest = sc->tc; 166 winlink_set_window(sc->wl, w); 167 } else 168 w = NULL; 169 sc->flags |= SPAWN_NONOTIFY; 170 171 /* Spawn the pane. */ 172 wp = spawn_pane(sc, cause); 173 if (wp == NULL) { 174 if (~sc->flags & SPAWN_RESPAWN) 175 winlink_remove(&s->windows, sc->wl); 176 return (NULL); 177 } 178 179 /* Set the name of the new window. */ 180 if (~sc->flags & SPAWN_RESPAWN) { 181 free(w->name); 182 if (sc->name != NULL) { 183 w->name = format_single(item, sc->name, c, s, NULL, 184 NULL); 185 options_set_number(w->options, "automatic-rename", 0); 186 } else 187 w->name = default_window_name(w); 188 } 189 190 /* Switch to the new window if required. */ 191 if (~sc->flags & SPAWN_DETACHED) 192 session_select(s, sc->wl->idx); 193 194 /* Fire notification if new window. */ 195 if (~sc->flags & SPAWN_RESPAWN) 196 notify_session_window("window-linked", s, w); 197 198 session_group_synchronize_from(s); 199 return (sc->wl); 200 } 201 202 struct window_pane * 203 spawn_pane(struct spawn_context *sc, char **cause) 204 { 205 struct cmdq_item *item = sc->item; 206 struct cmd_find_state *target = cmdq_get_target(item); 207 struct client *c = cmdq_get_client(item); 208 struct session *s = sc->s; 209 struct window *w = sc->wl->window; 210 struct window_pane *new_wp; 211 struct environ *child; 212 struct environ_entry *ee; 213 char **argv, *cp, **argvp, *argv0, *cwd, *new_cwd; 214 const char *cmd, *tmp; 215 int argc; 216 u_int idx; 217 struct termios now; 218 u_int hlimit; 219 struct winsize ws; 220 sigset_t set, oldset; 221 key_code key; 222 223 spawn_log(__func__, sc); 224 225 /* 226 * Work out the current working directory. If respawning, use 227 * the pane's stored one unless specified. 228 */ 229 if (sc->cwd != NULL) { 230 cwd = format_single(item, sc->cwd, c, target->s, NULL, NULL); 231 if (*cwd != '/') { 232 xasprintf(&new_cwd, "%s/%s", server_client_get_cwd(c, 233 target->s), cwd); 234 free(cwd); 235 cwd = new_cwd; 236 } 237 } else if (~sc->flags & SPAWN_RESPAWN) 238 cwd = xstrdup(server_client_get_cwd(c, target->s)); 239 else 240 cwd = NULL; 241 242 /* 243 * If we are respawning then get rid of the old process. Otherwise 244 * either create a new cell or assign to the one we are given. 245 */ 246 hlimit = options_get_number(s->options, "history-limit"); 247 if (sc->flags & SPAWN_RESPAWN) { 248 if (sc->wp0->fd != -1 && (~sc->flags & SPAWN_KILL)) { 249 window_pane_index(sc->wp0, &idx); 250 xasprintf(cause, "pane %s:%d.%u still active", 251 s->name, sc->wl->idx, idx); 252 free(cwd); 253 return (NULL); 254 } 255 if (sc->wp0->fd != -1) { 256 bufferevent_free(sc->wp0->event); 257 close(sc->wp0->fd); 258 } 259 window_pane_reset_mode_all(sc->wp0); 260 screen_reinit(&sc->wp0->base); 261 input_free(sc->wp0->ictx); 262 sc->wp0->ictx = NULL; 263 new_wp = sc->wp0; 264 new_wp->flags &= ~(PANE_STATUSREADY|PANE_STATUSDRAWN); 265 } else if (sc->lc == NULL) { 266 new_wp = window_add_pane(w, NULL, hlimit, sc->flags); 267 layout_init(w, new_wp); 268 } else { 269 new_wp = window_add_pane(w, sc->wp0, hlimit, sc->flags); 270 if (sc->flags & SPAWN_ZOOM) 271 layout_assign_pane(sc->lc, new_wp, 1); 272 else 273 layout_assign_pane(sc->lc, new_wp, 0); 274 } 275 276 /* 277 * Now we have a pane with nothing running in it ready for the new 278 * process. Work out the command and arguments and store the working 279 * directory. 280 */ 281 if (sc->argc == 0 && (~sc->flags & SPAWN_RESPAWN)) { 282 cmd = options_get_string(s->options, "default-command"); 283 if (cmd != NULL && *cmd != '\0') { 284 argc = 1; 285 argv = __UNCONST(&cmd); 286 } else { 287 argc = 0; 288 argv = NULL; 289 } 290 } else { 291 argc = sc->argc; 292 argv = sc->argv; 293 } 294 if (cwd != NULL) { 295 free(new_wp->cwd); 296 new_wp->cwd = cwd; 297 } 298 299 /* 300 * Replace the stored arguments if there are new ones. If not, the 301 * existing ones will be used (they will only exist for respawn). 302 */ 303 if (argc > 0) { 304 cmd_free_argv(new_wp->argc, new_wp->argv); 305 new_wp->argc = argc; 306 new_wp->argv = cmd_copy_argv(argc, argv); 307 } 308 309 /* Create an environment for this pane. */ 310 child = environ_for_session(s, 0); 311 if (sc->environ != NULL) 312 environ_copy(sc->environ, child); 313 environ_set(child, "TMUX_PANE", 0, "%%%u", new_wp->id); 314 315 /* 316 * Then the PATH environment variable. The session one is replaced from 317 * the client if there is one because otherwise running "tmux new 318 * myprogram" wouldn't work if myprogram isn't in the session's path. 319 */ 320 if (c != NULL && c->session == NULL) { /* only unattached clients */ 321 ee = environ_find(c->environ, "PATH"); 322 if (ee != NULL) 323 environ_set(child, "PATH", 0, "%s", ee->value); 324 } 325 if (environ_find(child, "PATH") == NULL) 326 environ_set(child, "PATH", 0, "%s", _PATH_DEFPATH); 327 328 /* Then the shell. If respawning, use the old one. */ 329 if (~sc->flags & SPAWN_RESPAWN) { 330 tmp = options_get_string(s->options, "default-shell"); 331 if (!checkshell(tmp)) 332 tmp = _PATH_BSHELL; 333 free(new_wp->shell); 334 new_wp->shell = xstrdup(tmp); 335 } 336 environ_set(child, "SHELL", 0, "%s", new_wp->shell); 337 338 /* Log the arguments we are going to use. */ 339 log_debug("%s: shell=%s", __func__, new_wp->shell); 340 if (new_wp->argc != 0) { 341 cp = cmd_stringify_argv(new_wp->argc, new_wp->argv); 342 log_debug("%s: cmd=%s", __func__, cp); 343 free(cp); 344 } 345 log_debug("%s: cwd=%s", __func__, new_wp->cwd); 346 cmd_log_argv(new_wp->argc, new_wp->argv, "%s", __func__); 347 environ_log(child, "%s: environment ", __func__); 348 349 /* Initialize the window size. */ 350 memset(&ws, 0, sizeof ws); 351 ws.ws_col = screen_size_x(&new_wp->base); 352 ws.ws_row = screen_size_y(&new_wp->base); 353 ws.ws_xpixel = w->xpixel * ws.ws_col; 354 ws.ws_ypixel = w->ypixel * ws.ws_row; 355 356 /* Block signals until fork has completed. */ 357 sigfillset(&set); 358 sigprocmask(SIG_BLOCK, &set, &oldset); 359 360 /* If the command is empty, don't fork a child process. */ 361 if (sc->flags & SPAWN_EMPTY) { 362 new_wp->flags |= PANE_EMPTY; 363 new_wp->base.mode &= ~MODE_CURSOR; 364 new_wp->base.mode |= MODE_CRLF; 365 goto complete; 366 } 367 368 /* Fork the new process. */ 369 new_wp->pid = fdforkpty(ptm_fd, &new_wp->fd, new_wp->tty, NULL, &ws); 370 if (new_wp->pid == -1) { 371 xasprintf(cause, "fork failed: %s", strerror(errno)); 372 new_wp->fd = -1; 373 if (~sc->flags & SPAWN_RESPAWN) { 374 server_client_remove_pane(new_wp); 375 layout_close_pane(new_wp); 376 window_remove_pane(w, new_wp); 377 } 378 sigprocmask(SIG_SETMASK, &oldset, NULL); 379 environ_free(child); 380 return (NULL); 381 } 382 383 /* In the parent process, everything is done now. */ 384 if (new_wp->pid != 0) { 385 #if defined(HAVE_SYSTEMD) && defined(ENABLE_CGROUPS) 386 /* 387 * Move the child process into a new cgroup for systemd-oomd 388 * isolation. 389 */ 390 if (systemd_move_pid_to_new_cgroup(new_wp->pid, cause) < 0) { 391 log_debug("%s: moving pane to new cgroup failed: %s", 392 __func__, *cause); 393 free (*cause); 394 } 395 #endif 396 goto complete; 397 } 398 399 /* 400 * Child process. Change to the working directory or home if that 401 * fails. 402 */ 403 if (chdir(new_wp->cwd) == 0) 404 environ_set(child, "PWD", 0, "%s", new_wp->cwd); 405 else if ((tmp = find_home()) != NULL && chdir(tmp) == 0) 406 environ_set(child, "PWD", 0, "%s", tmp); 407 else if (chdir("/") == 0) 408 environ_set(child, "PWD", 0, "/"); 409 else 410 fatal("chdir failed"); 411 412 /* 413 * Update terminal escape characters from the session if available and 414 * force VERASE to tmux's backspace. 415 */ 416 if (tcgetattr(STDIN_FILENO, &now) != 0) 417 _exit(1); 418 if (s->tio != NULL) 419 memcpy(now.c_cc, s->tio->c_cc, sizeof now.c_cc); 420 key = options_get_number(global_options, "backspace"); 421 if (key >= 0x7f) 422 now.c_cc[VERASE] = '\177'; 423 else 424 now.c_cc[VERASE] = key; 425 #ifdef IUTF8 426 now.c_iflag |= IUTF8; 427 #endif 428 if (tcsetattr(STDIN_FILENO, TCSANOW, &now) != 0) 429 _exit(1); 430 431 /* Clean up file descriptors and signals and update the environment. */ 432 proc_clear_signals(server_proc, 1); 433 closefrom(STDERR_FILENO + 1); 434 sigprocmask(SIG_SETMASK, &oldset, NULL); 435 log_close(); 436 environ_push(child); 437 438 /* 439 * If given multiple arguments, use execvp(). Copy the arguments to 440 * ensure they end in a NULL. 441 */ 442 if (new_wp->argc != 0 && new_wp->argc != 1) { 443 argvp = cmd_copy_argv(new_wp->argc, new_wp->argv); 444 execvp(argvp[0], argvp); 445 _exit(1); 446 } 447 448 /* 449 * If one argument, pass it to $SHELL -c. Otherwise create a login 450 * shell. 451 */ 452 cp = strrchr(new_wp->shell, '/'); 453 if (new_wp->argc == 1) { 454 tmp = new_wp->argv[0]; 455 if (cp != NULL && cp[1] != '\0') 456 xasprintf(&argv0, "%s", cp + 1); 457 else 458 xasprintf(&argv0, "%s", new_wp->shell); 459 execl(new_wp->shell, argv0, "-c", tmp, (char *)NULL); 460 _exit(1); 461 } 462 if (cp != NULL && cp[1] != '\0') 463 xasprintf(&argv0, "-%s", cp + 1); 464 else 465 xasprintf(&argv0, "-%s", new_wp->shell); 466 execl(new_wp->shell, argv0, (char *)NULL); 467 _exit(1); 468 469 complete: 470 #ifdef HAVE_UTEMPTER 471 if (~new_wp->flags & PANE_EMPTY) { 472 xasprintf(&cp, "tmux(%lu).%%%u", (long)getpid(), new_wp->id); 473 utempter_add_record(new_wp->fd, cp); 474 kill(getpid(), SIGCHLD); 475 free(cp); 476 } 477 #endif 478 479 new_wp->flags &= ~PANE_EXITED; 480 481 sigprocmask(SIG_SETMASK, &oldset, NULL); 482 window_pane_set_event(new_wp); 483 484 environ_free(child); 485 486 if (sc->flags & SPAWN_RESPAWN) 487 return (new_wp); 488 if ((~sc->flags & SPAWN_DETACHED) || w->active == NULL) { 489 if (sc->flags & SPAWN_NONOTIFY) 490 window_set_active_pane(w, new_wp, 0); 491 else 492 window_set_active_pane(w, new_wp, 1); 493 } 494 if (~sc->flags & SPAWN_NONOTIFY) 495 notify_window("window-layout-changed", w); 496 return (new_wp); 497 } 498