Annotation of src/usr.bin/tmux/spawn.c, Revision 1.15
1.15 ! nicm 1: /* $OpenBSD: spawn.c,v 1.14 2020/01/28 10:21:21 nicm Exp $ */
1.1 nicm 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 <paths.h>
23: #include <signal.h>
24: #include <stdlib.h>
25: #include <string.h>
26: #include <unistd.h>
27: #include <util.h>
28:
29: #include "tmux.h"
30:
31: /*
32: * Set up the environment and create a new window and pane or a new pane.
33: *
34: * We need to set up the following items:
35: *
36: * - history limit, comes from the session;
37: *
38: * - base index, comes from the session;
39: *
40: * - current working directory, may be specified - if it isn't it comes from
41: * either the client or the session;
42: *
43: * - PATH variable, comes from the client if any, otherwise from the session
44: * environment;
45: *
46: * - shell, comes from default-shell;
47: *
48: * - termios, comes from the session;
49: *
50: * - remaining environment, comes from the session.
51: */
52:
53: static void
54: spawn_log(const char *from, struct spawn_context *sc)
55: {
56: struct session *s = sc->s;
57: struct winlink *wl = sc->wl;
58: struct window_pane *wp0 = sc->wp0;
59: char tmp[128];
60: const char *name;
61:
62: log_debug("%s: %s, flags=%#x", from, sc->item->name, sc->flags);
63:
64: if (wl != NULL && wp0 != NULL)
65: xsnprintf(tmp, sizeof tmp, "wl=%d wp0=%%%u", wl->idx, wp0->id);
66: else if (wl != NULL)
67: xsnprintf(tmp, sizeof tmp, "wl=%d wp0=none", wl->idx);
68: else if (wp0 != NULL)
69: xsnprintf(tmp, sizeof tmp, "wl=none wp0=%%%u", wp0->id);
70: else
71: xsnprintf(tmp, sizeof tmp, "wl=none wp0=none");
72: log_debug("%s: s=$%u %s idx=%d", from, s->id, tmp, sc->idx);
73:
74: name = sc->name;
75: if (name == NULL)
76: name = "none";
77: log_debug("%s: name=%s", from, name);
78: }
79:
80: struct winlink *
81: spawn_window(struct spawn_context *sc, char **cause)
82: {
1.13 nicm 83: struct cmdq_item *item = sc->item;
84: struct client *c = item->client;
1.1 nicm 85: struct session *s = sc->s;
86: struct window *w;
87: struct window_pane *wp;
88: struct winlink *wl;
89: int idx = sc->idx;
1.12 nicm 90: u_int sx, sy, xpixel, ypixel;
1.1 nicm 91:
92: spawn_log(__func__, sc);
93:
94: /*
95: * If the window already exists, we are respawning, so destroy all the
96: * panes except one.
97: */
98: if (sc->flags & SPAWN_RESPAWN) {
99: w = sc->wl->window;
100: if (~sc->flags & SPAWN_KILL) {
101: TAILQ_FOREACH(wp, &w->panes, entry) {
102: if (wp->fd != -1)
103: break;
104: }
105: if (wp != NULL) {
106: xasprintf(cause, "window %s:%d still active",
107: s->name, sc->wl->idx);
108: return (NULL);
109: }
110: }
111:
112: sc->wp0 = TAILQ_FIRST(&w->panes);
113: TAILQ_REMOVE(&w->panes, sc->wp0, entry);
114:
115: layout_free(w);
116: window_destroy_panes(w);
117:
118: TAILQ_INSERT_HEAD(&w->panes, sc->wp0, entry);
119: window_pane_resize(sc->wp0, w->sx, w->sy);
120:
121: layout_init(w, sc->wp0);
122: window_set_active_pane(w, sc->wp0, 0);
123: }
124:
125: /*
126: * Otherwise we have no window so we will need to create one. First
127: * check if the given index already exists and destroy it if so.
128: */
129: if ((~sc->flags & SPAWN_RESPAWN) && idx != -1) {
130: wl = winlink_find_by_index(&s->windows, idx);
131: if (wl != NULL && (~sc->flags & SPAWN_KILL)) {
132: xasprintf(cause, "index %d in use", idx);
133: return (NULL);
134: }
135: if (wl != NULL) {
136: /*
137: * Can't use session_detach as it will destroy session
138: * if this makes it empty.
139: */
140: wl->flags &= ~WINLINK_ALERTFLAGS;
141: notify_session_window("window-unlinked", s, wl->window);
142: winlink_stack_remove(&s->lastw, wl);
143: winlink_remove(&s->windows, wl);
144:
145: if (s->curw == wl) {
146: s->curw = NULL;
147: sc->flags &= ~SPAWN_DETACHED;
148: }
149: }
150: }
151:
152: /* Then create a window if needed. */
153: if (~sc->flags & SPAWN_RESPAWN) {
154: if (idx == -1)
155: idx = -1 - options_get_number(s->options, "base-index");
156: if ((sc->wl = winlink_add(&s->windows, idx)) == NULL) {
157: xasprintf(cause, "couldn't add window %d", idx);
158: return (NULL);
159: }
1.12 nicm 160: default_window_size(sc->c, s, NULL, &sx, &sy, &xpixel, &ypixel,
161: -1);
162: if ((w = window_create(sx, sy, xpixel, ypixel)) == NULL) {
1.1 nicm 163: winlink_remove(&s->windows, sc->wl);
164: xasprintf(cause, "couldn't create window %d", idx);
165: return (NULL);
166: }
1.5 nicm 167: if (s->curw == NULL)
168: s->curw = sc->wl;
1.1 nicm 169: sc->wl->session = s;
1.8 nicm 170: w->latest = sc->c;
1.1 nicm 171: winlink_set_window(sc->wl, w);
172: } else
173: w = NULL;
174: sc->flags |= SPAWN_NONOTIFY;
175:
176: /* Spawn the pane. */
177: wp = spawn_pane(sc, cause);
178: if (wp == NULL) {
1.6 nicm 179: if (~sc->flags & SPAWN_RESPAWN)
1.1 nicm 180: winlink_remove(&s->windows, sc->wl);
181: return (NULL);
182: }
183:
184: /* Set the name of the new window. */
185: if (~sc->flags & SPAWN_RESPAWN) {
186: if (sc->name != NULL) {
1.13 nicm 187: w->name = format_single(item, sc->name, c, s, NULL,
188: NULL);
1.1 nicm 189: options_set_number(w->options, "automatic-rename", 0);
190: } else
191: w->name = xstrdup(default_window_name(w));
192: }
193:
194: /* Switch to the new window if required. */
195: if (~sc->flags & SPAWN_DETACHED)
196: session_select(s, sc->wl->idx);
197:
198: /* Fire notification if new window. */
199: if (~sc->flags & SPAWN_RESPAWN)
200: notify_session_window("window-linked", s, w);
201:
202: session_group_synchronize_from(s);
203: return (sc->wl);
204: }
205:
206: struct window_pane *
207: spawn_pane(struct spawn_context *sc, char **cause)
208: {
209: struct cmdq_item *item = sc->item;
210: struct client *c = item->client;
211: struct session *s = sc->s;
212: struct window *w = sc->wl->window;
213: struct window_pane *new_wp;
214: struct environ *child;
215: struct environ_entry *ee;
216: char **argv, *cp, **argvp, *argv0, *cwd;
217: const char *cmd, *tmp;
218: int argc;
219: u_int idx;
220: struct termios now;
221: u_int hlimit;
222: struct winsize ws;
223: sigset_t set, oldset;
1.11 nicm 224: key_code key;
1.1 nicm 225:
226: spawn_log(__func__, sc);
227:
228: /*
1.14 nicm 229: * Work out the current working directory. If respawning, use
230: * the pane's stored one unless specified.
231: */
232: if (sc->cwd != NULL)
1.15 ! nicm 233: cwd = format_single(item, sc->cwd, c, item->target.s, NULL, NULL);
1.14 nicm 234: else if (~sc->flags & SPAWN_RESPAWN)
1.15 ! nicm 235: cwd = xstrdup(server_client_get_cwd(c, item->target.s));
1.14 nicm 236: else
237: cwd = NULL;
238:
239: /*
1.1 nicm 240: * If we are respawning then get rid of the old process. Otherwise
241: * either create a new cell or assign to the one we are given.
242: */
243: hlimit = options_get_number(s->options, "history-limit");
244: if (sc->flags & SPAWN_RESPAWN) {
245: if (sc->wp0->fd != -1 && (~sc->flags & SPAWN_KILL)) {
246: window_pane_index(sc->wp0, &idx);
247: xasprintf(cause, "pane %s:%d.%u still active",
248: s->name, sc->wl->idx, idx);
1.14 nicm 249: free(cwd);
1.1 nicm 250: return (NULL);
251: }
252: if (sc->wp0->fd != -1) {
253: bufferevent_free(sc->wp0->event);
254: close(sc->wp0->fd);
255: }
256: window_pane_reset_mode_all(sc->wp0);
257: screen_reinit(&sc->wp0->base);
258: input_init(sc->wp0);
259: new_wp = sc->wp0;
260: new_wp->flags &= ~(PANE_STATUSREADY|PANE_STATUSDRAWN);
261: } else if (sc->lc == NULL) {
262: new_wp = window_add_pane(w, NULL, hlimit, sc->flags);
263: layout_init(w, new_wp);
264: } else {
265: new_wp = window_add_pane(w, sc->wp0, hlimit, sc->flags);
266: layout_assign_pane(sc->lc, new_wp);
267: }
268:
269: /*
1.14 nicm 270: * Now we have a pane with nothing running in it ready for the new process.
271: * Work out the command and arguments and store the working directory.
1.1 nicm 272: */
1.10 nicm 273: if (sc->argc == 0 && (~sc->flags & SPAWN_RESPAWN)) {
1.1 nicm 274: cmd = options_get_string(s->options, "default-command");
275: if (cmd != NULL && *cmd != '\0') {
276: argc = 1;
277: argv = (char **)&cmd;
278: } else {
279: argc = 0;
280: argv = NULL;
281: }
282: } else {
283: argc = sc->argc;
284: argv = sc->argv;
285: }
1.14 nicm 286: if (cwd != NULL) {
287: free(new_wp->cwd);
288: new_wp->cwd = cwd;
289: }
1.1 nicm 290:
291: /*
292: * Replace the stored arguments if there are new ones. If not, the
293: * existing ones will be used (they will only exist for respawn).
294: */
295: if (argc > 0) {
296: cmd_free_argv(new_wp->argc, new_wp->argv);
297: new_wp->argc = argc;
298: new_wp->argv = cmd_copy_argv(argc, argv);
299: }
300:
301: /* Create an environment for this pane. */
302: child = environ_for_session(s, 0);
1.2 nicm 303: if (sc->environ != NULL)
304: environ_copy(sc->environ, child);
1.1 nicm 305: environ_set(child, "TMUX_PANE", "%%%u", new_wp->id);
306:
307: /*
308: * Then the PATH environment variable. The session one is replaced from
309: * the client if there is one because otherwise running "tmux new
310: * myprogram" wouldn't work if myprogram isn't in the session's path.
311: */
312: if (c != NULL && c->session == NULL) { /* only unattached clients */
313: ee = environ_find(c->environ, "PATH");
314: if (ee != NULL)
315: environ_set(child, "PATH", "%s", ee->value);
316: }
317: if (environ_find(child, "PATH") == NULL)
318: environ_set(child, "%s", _PATH_DEFPATH);
319:
320: /* Then the shell. If respawning, use the old one. */
321: if (~sc->flags & SPAWN_RESPAWN) {
322: tmp = options_get_string(s->options, "default-shell");
323: if (*tmp == '\0' || areshell(tmp))
324: tmp = _PATH_BSHELL;
325: free(new_wp->shell);
326: new_wp->shell = xstrdup(tmp);
327: }
328: environ_set(child, "SHELL", "%s", new_wp->shell);
329:
330: /* Log the arguments we are going to use. */
331: log_debug("%s: shell=%s", __func__, new_wp->shell);
332: if (new_wp->argc != 0) {
333: cp = cmd_stringify_argv(new_wp->argc, new_wp->argv);
334: log_debug("%s: cmd=%s", __func__, cp);
335: free(cp);
336: }
337: if (cwd != NULL)
338: log_debug("%s: cwd=%s", __func__, cwd);
1.4 nicm 339: cmd_log_argv(new_wp->argc, new_wp->argv, "%s", __func__);
1.1 nicm 340: environ_log(child, "%s: environment ", __func__);
341:
342: /* Initialize the window size. */
343: memset(&ws, 0, sizeof ws);
344: ws.ws_col = screen_size_x(&new_wp->base);
345: ws.ws_row = screen_size_y(&new_wp->base);
1.12 nicm 346: ws.ws_xpixel = w->xpixel * ws.ws_col;
347: ws.ws_ypixel = w->ypixel * ws.ws_row;
1.1 nicm 348:
349: /* Block signals until fork has completed. */
350: sigfillset(&set);
351: sigprocmask(SIG_BLOCK, &set, &oldset);
1.7 nicm 352:
353: /* If the command is empty, don't fork a child process. */
354: if (sc->flags & SPAWN_EMPTY) {
355: new_wp->flags |= PANE_EMPTY;
356: new_wp->base.mode &= ~MODE_CURSOR;
357: new_wp->base.mode |= MODE_CRLF;
358: goto complete;
359: }
1.1 nicm 360:
361: /* Fork the new process. */
362: new_wp->pid = fdforkpty(ptm_fd, &new_wp->fd, new_wp->tty, NULL, &ws);
363: if (new_wp->pid == -1) {
364: xasprintf(cause, "fork failed: %s", strerror(errno));
365: new_wp->fd = -1;
366: if (~sc->flags & SPAWN_RESPAWN) {
367: layout_close_pane(new_wp);
368: window_remove_pane(w, new_wp);
369: }
370: sigprocmask(SIG_SETMASK, &oldset, NULL);
371: return (NULL);
372: }
373:
374: /* In the parent process, everything is done now. */
1.3 nicm 375: if (new_wp->pid != 0)
376: goto complete;
1.1 nicm 377:
378: /*
379: * Child process. Change to the working directory or home if that
380: * fails.
381: */
382: if (chdir(new_wp->cwd) != 0) {
383: if ((tmp = find_home()) == NULL || chdir(tmp) != 0)
384: chdir("/");
385: }
386:
387: /*
388: * Update terminal escape characters from the session if available and
1.11 nicm 389: * force VERASE to tmux's backspace.
1.1 nicm 390: */
391: if (tcgetattr(STDIN_FILENO, &now) != 0)
392: _exit(1);
393: if (s->tio != NULL)
394: memcpy(now.c_cc, s->tio->c_cc, sizeof now.c_cc);
1.11 nicm 395: key = options_get_number(global_options, "backspace");
396: if (key >= 0x7f)
397: now.c_cc[VERASE] = '\177';
398: else
399: now.c_cc[VERASE] = key;
1.1 nicm 400: if (tcsetattr(STDIN_FILENO, TCSANOW, &now) != 0)
401: _exit(1);
402:
403: /* Clean up file descriptors and signals and update the environment. */
404: closefrom(STDERR_FILENO + 1);
405: proc_clear_signals(server_proc, 1);
406: sigprocmask(SIG_SETMASK, &oldset, NULL);
407: log_close();
408: environ_push(child);
409:
410: /*
411: * If given multiple arguments, use execvp(). Copy the arguments to
412: * ensure they end in a NULL.
413: */
414: if (new_wp->argc != 0 && new_wp->argc != 1) {
415: argvp = cmd_copy_argv(new_wp->argc, new_wp->argv);
416: execvp(argvp[0], argvp);
417: _exit(1);
418: }
419:
420: /*
421: * If one argument, pass it to $SHELL -c. Otherwise create a login
422: * shell.
423: */
424: cp = strrchr(new_wp->shell, '/');
425: if (new_wp->argc == 1) {
426: tmp = new_wp->argv[0];
427: if (cp != NULL && cp[1] != '\0')
428: xasprintf(&argv0, "%s", cp + 1);
429: else
430: xasprintf(&argv0, "%s", new_wp->shell);
431: execl(new_wp->shell, argv0, "-c", tmp, (char *)NULL);
432: _exit(1);
433: }
434: if (cp != NULL && cp[1] != '\0')
435: xasprintf(&argv0, "-%s", cp + 1);
436: else
437: xasprintf(&argv0, "-%s", new_wp->shell);
438: execl(new_wp->shell, argv0, (char *)NULL);
439: _exit(1);
1.3 nicm 440:
441: complete:
442: new_wp->pipe_off = 0;
443: new_wp->flags &= ~PANE_EXITED;
444:
445: sigprocmask(SIG_SETMASK, &oldset, NULL);
446: window_pane_set_event(new_wp);
447:
448: if (sc->flags & SPAWN_RESPAWN)
449: return (new_wp);
450: if ((~sc->flags & SPAWN_DETACHED) || w->active == NULL) {
451: if (sc->flags & SPAWN_NONOTIFY)
452: window_set_active_pane(w, new_wp, 0);
453: else
454: window_set_active_pane(w, new_wp, 1);
455: }
456: if (~sc->flags & SPAWN_NONOTIFY)
457: notify_window("window-layout-changed", w);
458: return (new_wp);
1.1 nicm 459: }