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 char tmp[128]; 58 const char *name; 59 60 log_debug("%s: %s, flags=%#x", from, sc->item->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 72 name = sc->name; 73 if (name == NULL) 74 name = "none"; 75 log_debug("%s: name=%s", from, name); 76 } 77 78 struct winlink * 79 spawn_window(struct spawn_context *sc, char **cause) 80 { 81 struct cmdq_item *item = sc->item; 82 struct client *c = item->client; 83 struct session *s = sc->s; 84 struct window *w; 85 struct window_pane *wp; 86 struct winlink *wl; 87 int idx = sc->idx; 88 u_int sx, sy, xpixel, ypixel; 89 90 spawn_log(__func__, sc); 91 92 /* 93 * If the window already exists, we are respawning, so destroy all the 94 * panes except one. 95 */ 96 if (sc->flags & SPAWN_RESPAWN) { 97 w = sc->wl->window; 98 if (~sc->flags & SPAWN_KILL) { 99 TAILQ_FOREACH(wp, &w->panes, entry) { 100 if (wp->fd != -1) 101 break; 102 } 103 if (wp != NULL) { 104 xasprintf(cause, "window %s:%d still active", 105 s->name, sc->wl->idx); 106 return (NULL); 107 } 108 } 109 110 sc->wp0 = TAILQ_FIRST(&w->panes); 111 TAILQ_REMOVE(&w->panes, sc->wp0, entry); 112 113 layout_free(w); 114 window_destroy_panes(w); 115 116 TAILQ_INSERT_HEAD(&w->panes, sc->wp0, entry); 117 window_pane_resize(sc->wp0, w->sx, w->sy); 118 119 layout_init(w, sc->wp0); 120 window_set_active_pane(w, sc->wp0, 0); 121 } 122 123 /* 124 * Otherwise we have no window so we will need to create one. First 125 * check if the given index already exists and destroy it if so. 126 */ 127 if ((~sc->flags & SPAWN_RESPAWN) && idx != -1) { 128 wl = winlink_find_by_index(&s->windows, idx); 129 if (wl != NULL && (~sc->flags & SPAWN_KILL)) { 130 xasprintf(cause, "index %d in use", idx); 131 return (NULL); 132 } 133 if (wl != NULL) { 134 /* 135 * Can't use session_detach as it will destroy session 136 * if this makes it empty. 137 */ 138 wl->flags &= ~WINLINK_ALERTFLAGS; 139 notify_session_window("window-unlinked", s, wl->window); 140 winlink_stack_remove(&s->lastw, wl); 141 winlink_remove(&s->windows, wl); 142 143 if (s->curw == wl) { 144 s->curw = NULL; 145 sc->flags &= ~SPAWN_DETACHED; 146 } 147 } 148 } 149 150 /* Then create a window if needed. */ 151 if (~sc->flags & SPAWN_RESPAWN) { 152 if (idx == -1) 153 idx = -1 - options_get_number(s->options, "base-index"); 154 if ((sc->wl = winlink_add(&s->windows, idx)) == NULL) { 155 xasprintf(cause, "couldn't add window %d", idx); 156 return (NULL); 157 } 158 default_window_size(sc->c, s, NULL, &sx, &sy, &xpixel, &ypixel, 159 -1); 160 if ((w = window_create(sx, sy, xpixel, ypixel)) == NULL) { 161 winlink_remove(&s->windows, sc->wl); 162 xasprintf(cause, "couldn't create window %d", idx); 163 return (NULL); 164 } 165 if (s->curw == NULL) 166 s->curw = sc->wl; 167 sc->wl->session = s; 168 w->latest = sc->c; 169 winlink_set_window(sc->wl, w); 170 } else 171 w = NULL; 172 sc->flags |= SPAWN_NONOTIFY; 173 174 /* Spawn the pane. */ 175 wp = spawn_pane(sc, cause); 176 if (wp == NULL) { 177 if (~sc->flags & SPAWN_RESPAWN) 178 winlink_remove(&s->windows, sc->wl); 179 return (NULL); 180 } 181 182 /* Set the name of the new window. */ 183 if (~sc->flags & SPAWN_RESPAWN) { 184 if (sc->name != NULL) { 185 w->name = format_single(item, sc->name, c, s, NULL, 186 NULL); 187 options_set_number(w->options, "automatic-rename", 0); 188 } else 189 w->name = xstrdup(default_window_name(w)); 190 } 191 192 /* Switch to the new window if required. */ 193 if (~sc->flags & SPAWN_DETACHED) 194 session_select(s, sc->wl->idx); 195 196 /* Fire notification if new window. */ 197 if (~sc->flags & SPAWN_RESPAWN) 198 notify_session_window("window-linked", s, w); 199 200 session_group_synchronize_from(s); 201 return (sc->wl); 202 } 203 204 struct window_pane * 205 spawn_pane(struct spawn_context *sc, char **cause) 206 { 207 struct cmdq_item *item = sc->item; 208 struct client *c = item->client; 209 struct session *s = sc->s; 210 struct window *w = sc->wl->window; 211 struct window_pane *new_wp; 212 struct environ *child; 213 struct environ_entry *ee; 214 char **argv, *cp, **argvp, *argv0, *cwd; 215 const char *cmd, *tmp; 216 int argc; 217 u_int idx; 218 struct termios now; 219 u_int hlimit; 220 struct winsize ws; 221 sigset_t set, oldset; 222 key_code key; 223 224 spawn_log(__func__, sc); 225 226 /* 227 * Work out the current working directory. If respawning, use 228 * the pane's stored one unless specified. 229 */ 230 if (sc->cwd != NULL) 231 cwd = format_single(item, sc->cwd, c, item->target.s, NULL, NULL); 232 else if (~sc->flags & SPAWN_RESPAWN) 233 cwd = xstrdup(server_client_get_cwd(c, item->target.s)); 234 else 235 cwd = NULL; 236 237 /* 238 * If we are respawning then get rid of the old process. Otherwise 239 * either create a new cell or assign to the one we are given. 240 */ 241 hlimit = options_get_number(s->options, "history-limit"); 242 if (sc->flags & SPAWN_RESPAWN) { 243 if (sc->wp0->fd != -1 && (~sc->flags & SPAWN_KILL)) { 244 window_pane_index(sc->wp0, &idx); 245 xasprintf(cause, "pane %s:%d.%u still active", 246 s->name, sc->wl->idx, idx); 247 free(cwd); 248 return (NULL); 249 } 250 if (sc->wp0->fd != -1) { 251 bufferevent_free(sc->wp0->event); 252 close(sc->wp0->fd); 253 } 254 window_pane_reset_mode_all(sc->wp0); 255 screen_reinit(&sc->wp0->base); 256 input_init(sc->wp0); 257 new_wp = sc->wp0; 258 new_wp->flags &= ~(PANE_STATUSREADY|PANE_STATUSDRAWN); 259 } else if (sc->lc == NULL) { 260 new_wp = window_add_pane(w, NULL, hlimit, sc->flags); 261 layout_init(w, new_wp); 262 } else { 263 new_wp = window_add_pane(w, sc->wp0, hlimit, sc->flags); 264 layout_assign_pane(sc->lc, new_wp); 265 } 266 267 /* 268 * Now we have a pane with nothing running in it ready for the new process. 269 * Work out the command and arguments and store the working directory. 270 */ 271 if (sc->argc == 0 && (~sc->flags & SPAWN_RESPAWN)) { 272 cmd = options_get_string(s->options, "default-command"); 273 if (cmd != NULL && *cmd != '\0') { 274 argc = 1; 275 argv = __UNCONST(&cmd); 276 } else { 277 argc = 0; 278 argv = NULL; 279 } 280 } else { 281 argc = sc->argc; 282 argv = sc->argv; 283 } 284 if (cwd != NULL) { 285 free(new_wp->cwd); 286 new_wp->cwd = cwd; 287 } 288 289 /* 290 * Replace the stored arguments if there are new ones. If not, the 291 * existing ones will be used (they will only exist for respawn). 292 */ 293 if (argc > 0) { 294 cmd_free_argv(new_wp->argc, new_wp->argv); 295 new_wp->argc = argc; 296 new_wp->argv = cmd_copy_argv(argc, argv); 297 } 298 299 /* Create an environment for this pane. */ 300 child = environ_for_session(s, 0); 301 if (sc->environ != NULL) 302 environ_copy(sc->environ, child); 303 environ_set(child, "TMUX_PANE", "%%%u", new_wp->id); 304 305 /* 306 * Then the PATH environment variable. The session one is replaced from 307 * the client if there is one because otherwise running "tmux new 308 * myprogram" wouldn't work if myprogram isn't in the session's path. 309 */ 310 if (c != NULL && c->session == NULL) { /* only unattached clients */ 311 ee = environ_find(c->environ, "PATH"); 312 if (ee != NULL) 313 environ_set(child, "PATH", "%s", ee->value); 314 } 315 if (environ_find(child, "PATH") == NULL) 316 environ_set(child, "%s", _PATH_DEFPATH); 317 318 /* Then the shell. If respawning, use the old one. */ 319 if (~sc->flags & SPAWN_RESPAWN) { 320 tmp = options_get_string(s->options, "default-shell"); 321 if (*tmp == '\0' || areshell(tmp)) 322 tmp = _PATH_BSHELL; 323 free(new_wp->shell); 324 new_wp->shell = xstrdup(tmp); 325 } 326 environ_set(child, "SHELL", "%s", new_wp->shell); 327 328 /* Log the arguments we are going to use. */ 329 log_debug("%s: shell=%s", __func__, new_wp->shell); 330 if (new_wp->argc != 0) { 331 cp = cmd_stringify_argv(new_wp->argc, new_wp->argv); 332 log_debug("%s: cmd=%s", __func__, cp); 333 free(cp); 334 } 335 if (cwd != NULL) 336 log_debug("%s: cwd=%s", __func__, cwd); 337 cmd_log_argv(new_wp->argc, new_wp->argv, "%s", __func__); 338 environ_log(child, "%s: environment ", __func__); 339 340 /* Initialize the window size. */ 341 memset(&ws, 0, sizeof ws); 342 ws.ws_col = screen_size_x(&new_wp->base); 343 ws.ws_row = screen_size_y(&new_wp->base); 344 ws.ws_xpixel = w->xpixel * ws.ws_col; 345 ws.ws_ypixel = w->ypixel * ws.ws_row; 346 347 /* Block signals until fork has completed. */ 348 sigfillset(&set); 349 sigprocmask(SIG_BLOCK, &set, &oldset); 350 351 /* If the command is empty, don't fork a child process. */ 352 if (sc->flags & SPAWN_EMPTY) { 353 new_wp->flags |= PANE_EMPTY; 354 new_wp->base.mode &= ~MODE_CURSOR; 355 new_wp->base.mode |= MODE_CRLF; 356 goto complete; 357 } 358 359 /* Fork the new process. */ 360 new_wp->pid = fdforkpty(ptm_fd, &new_wp->fd, new_wp->tty, NULL, &ws); 361 if (new_wp->pid == -1) { 362 xasprintf(cause, "fork failed: %s", strerror(errno)); 363 new_wp->fd = -1; 364 if (~sc->flags & SPAWN_RESPAWN) { 365 layout_close_pane(new_wp); 366 window_remove_pane(w, new_wp); 367 } 368 sigprocmask(SIG_SETMASK, &oldset, NULL); 369 return (NULL); 370 } 371 372 /* In the parent process, everything is done now. */ 373 if (new_wp->pid != 0) 374 goto complete; 375 376 /* 377 * Child process. Change to the working directory or home if that 378 * fails. 379 */ 380 if (chdir(new_wp->cwd) != 0) { 381 if ((tmp = find_home()) == NULL || chdir(tmp) != 0) 382 chdir("/"); 383 } 384 385 /* 386 * Update terminal escape characters from the session if available and 387 * force VERASE to tmux's backspace. 388 */ 389 if (tcgetattr(STDIN_FILENO, &now) != 0) 390 _exit(1); 391 if (s->tio != NULL) 392 memcpy(now.c_cc, s->tio->c_cc, sizeof now.c_cc); 393 key = options_get_number(global_options, "backspace"); 394 if (key >= 0x7f) 395 now.c_cc[VERASE] = '\177'; 396 else 397 now.c_cc[VERASE] = key; 398 if (tcsetattr(STDIN_FILENO, TCSANOW, &now) != 0) 399 _exit(1); 400 401 /* Clean up file descriptors and signals and update the environment. */ 402 closefrom(STDERR_FILENO + 1); 403 proc_clear_signals(server_proc, 1); 404 sigprocmask(SIG_SETMASK, &oldset, NULL); 405 log_close(); 406 environ_push(child); 407 408 /* 409 * If given multiple arguments, use execvp(). Copy the arguments to 410 * ensure they end in a NULL. 411 */ 412 if (new_wp->argc != 0 && new_wp->argc != 1) { 413 argvp = cmd_copy_argv(new_wp->argc, new_wp->argv); 414 execvp(argvp[0], argvp); 415 _exit(1); 416 } 417 418 /* 419 * If one argument, pass it to $SHELL -c. Otherwise create a login 420 * shell. 421 */ 422 cp = strrchr(new_wp->shell, '/'); 423 if (new_wp->argc == 1) { 424 tmp = new_wp->argv[0]; 425 if (cp != NULL && cp[1] != '\0') 426 xasprintf(&argv0, "%s", cp + 1); 427 else 428 xasprintf(&argv0, "%s", new_wp->shell); 429 execl(new_wp->shell, argv0, "-c", tmp, (char *)NULL); 430 _exit(1); 431 } 432 if (cp != NULL && cp[1] != '\0') 433 xasprintf(&argv0, "-%s", cp + 1); 434 else 435 xasprintf(&argv0, "-%s", new_wp->shell); 436 execl(new_wp->shell, argv0, (char *)NULL); 437 _exit(1); 438 439 complete: 440 #ifdef HAVE_UTEMPTER 441 if (~new_wp->flags & PANE_EMPTY) { 442 xasprintf(&cp, "tmux(%lu).%%%u", (long)getpid(), new_wp->id); 443 utempter_add_record(new_wp->fd, cp); 444 kill(getpid(), SIGCHLD); 445 free(cp); 446 } 447 #endif 448 449 new_wp->pipe_off = 0; 450 new_wp->flags &= ~PANE_EXITED; 451 452 sigprocmask(SIG_SETMASK, &oldset, NULL); 453 window_pane_set_event(new_wp); 454 455 if (sc->flags & SPAWN_RESPAWN) 456 return (new_wp); 457 if ((~sc->flags & SPAWN_DETACHED) || w->active == NULL) { 458 if (sc->flags & SPAWN_NONOTIFY) 459 window_set_active_pane(w, new_wp, 0); 460 else 461 window_set_active_pane(w, new_wp, 1); 462 } 463 if (~sc->flags & SPAWN_NONOTIFY) 464 notify_window("window-layout-changed", w); 465 return (new_wp); 466 } 467