xref: /openbsd-src/usr.bin/tmux/tmux.c (revision 04924df597e93aa6f9f08a588d1cff7dabdc8ef8)
1 /* $OpenBSD: tmux.c,v 1.52 2009/10/25 21:11:21 nicm Exp $ */
2 
3 /*
4  * Copyright (c) 2007 Nicholas Marriott <nicm@users.sourceforge.net>
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 #include <sys/stat.h>
21 
22 #include <errno.h>
23 #include <paths.h>
24 #include <pwd.h>
25 #include <signal.h>
26 #include <stdlib.h>
27 #include <string.h>
28 #include <syslog.h>
29 #include <unistd.h>
30 
31 #include "tmux.h"
32 
33 #ifdef DEBUG
34 const char	*malloc_options = "AFGJPX";
35 #endif
36 
37 volatile sig_atomic_t sigwinch;
38 volatile sig_atomic_t sigterm;
39 volatile sig_atomic_t sigcont;
40 volatile sig_atomic_t sigchld;
41 volatile sig_atomic_t sigusr1;
42 volatile sig_atomic_t sigusr2;
43 
44 char		*cfg_file;
45 struct options	 global_s_options;	/* session options */
46 struct options	 global_w_options;	/* window options */
47 struct environ	 global_environ;
48 
49 int		 debug_level;
50 int		 be_quiet;
51 time_t		 start_time;
52 char		*socket_path;
53 int		 login_shell;
54 
55 __dead void	 usage(void);
56 void	 	 fill_session(struct msg_command_data *);
57 char 		*makesockpath(const char *);
58 int		 dispatch_imsg(struct imsgbuf *, const char *, int *);
59 __dead void	 shell_exec(const char *, const char *);
60 
61 __dead void
62 usage(void)
63 {
64 	fprintf(stderr,
65 	    "usage: %s [-28lquv] [-c shell-command] [-f file] [-L socket-name]\n"
66 	    "            [-S socket-path] [command [flags]]\n",
67 	    __progname);
68 	exit(1);
69 }
70 
71 void
72 logfile(const char *name)
73 {
74 	char	*path;
75 
76 	log_close();
77 	if (debug_level > 0) {
78 		xasprintf(&path, "tmux-%s-%ld.log", name, (long) getpid());
79 		log_open_file(debug_level, path);
80 		xfree(path);
81 	}
82 }
83 
84 void
85 sighandler(int sig)
86 {
87 	int	saved_errno;
88 
89 	saved_errno = errno;
90 	switch (sig) {
91 	case SIGWINCH:
92 		sigwinch = 1;
93 		break;
94 	case SIGTERM:
95 		sigterm = 1;
96 		break;
97 	case SIGCHLD:
98 		sigchld = 1;
99 		break;
100 	case SIGCONT:
101 		sigcont = 1;
102 		break;
103 	case SIGUSR1:
104 		sigusr1 = 1;
105 		break;
106 	case SIGUSR2:
107 		sigusr2 = 1;
108 		break;
109 	}
110 	errno = saved_errno;
111 }
112 
113 void
114 siginit(void)
115 {
116 	struct sigaction	 act;
117 
118 	memset(&act, 0, sizeof act);
119 	sigemptyset(&act.sa_mask);
120 	act.sa_flags = SA_RESTART;
121 
122 	act.sa_handler = SIG_IGN;
123 	if (sigaction(SIGPIPE, &act, NULL) != 0)
124 		fatal("sigaction failed");
125 	if (sigaction(SIGINT, &act, NULL) != 0)
126 		fatal("sigaction failed");
127 	if (sigaction(SIGTSTP, &act, NULL) != 0)
128 		fatal("sigaction failed");
129 	if (sigaction(SIGQUIT, &act, NULL) != 0)
130 		fatal("sigaction failed");
131 
132 	act.sa_handler = sighandler;
133 	if (sigaction(SIGWINCH, &act, NULL) != 0)
134 		fatal("sigaction failed");
135 	if (sigaction(SIGTERM, &act, NULL) != 0)
136 		fatal("sigaction failed");
137 	if (sigaction(SIGCHLD, &act, NULL) != 0)
138 		fatal("sigaction failed");
139 	if (sigaction(SIGUSR1, &act, NULL) != 0)
140 		fatal("sigaction failed");
141 	if (sigaction(SIGUSR2, &act, NULL) != 0)
142 		fatal("sigaction failed");
143 }
144 
145 void
146 sigreset(void)
147 {
148 	struct sigaction act;
149 
150 	memset(&act, 0, sizeof act);
151 	sigemptyset(&act.sa_mask);
152 
153 	act.sa_handler = SIG_DFL;
154 	if (sigaction(SIGPIPE, &act, NULL) != 0)
155 		fatal("sigaction failed");
156 	if (sigaction(SIGUSR1, &act, NULL) != 0)
157 		fatal("sigaction failed");
158 	if (sigaction(SIGUSR2, &act, NULL) != 0)
159 		fatal("sigaction failed");
160 	if (sigaction(SIGINT, &act, NULL) != 0)
161 		fatal("sigaction failed");
162 	if (sigaction(SIGTSTP, &act, NULL) != 0)
163 		fatal("sigaction failed");
164 	if (sigaction(SIGQUIT, &act, NULL) != 0)
165 		fatal("sigaction failed");
166 	if (sigaction(SIGWINCH, &act, NULL) != 0)
167 		fatal("sigaction failed");
168 	if (sigaction(SIGTERM, &act, NULL) != 0)
169 		fatal("sigaction failed");
170 	if (sigaction(SIGCHLD, &act, NULL) != 0)
171 		fatal("sigaction failed");
172 }
173 
174 const char *
175 getshell(void)
176 {
177 	struct passwd	*pw;
178 	const char	*shell;
179 
180 	shell = getenv("SHELL");
181 	if (checkshell(shell))
182 		return (shell);
183 
184 	pw = getpwuid(getuid());
185 	if (pw != NULL && checkshell(pw->pw_shell))
186 		return (pw->pw_shell);
187 
188 	return (_PATH_BSHELL);
189 }
190 
191 int
192 checkshell(const char *shell)
193 {
194 	if (shell == NULL || *shell == '\0' || areshell(shell))
195 		return (0);
196 	if (access(shell, X_OK) != 0)
197 		return (0);
198 	return (1);
199 }
200 
201 int
202 areshell(const char *shell)
203 {
204 	const char	*progname, *ptr;
205 
206 	if ((ptr = strrchr(shell, '/')) != NULL)
207 		ptr++;
208 	else
209 		ptr = shell;
210 	progname = __progname;
211 	if (*progname == '-')
212 		progname++;
213 	if (strcmp(ptr, progname) == 0)
214 		return (1);
215 	return (0);
216 }
217 
218 void
219 fill_session(struct msg_command_data *data)
220 {
221 	char		*env, *ptr1, *ptr2, buf[256];
222 	size_t		 len;
223 	const char	*errstr;
224 	long long	 ll;
225 
226 	data->pid = -1;
227 	if ((env = getenv("TMUX")) == NULL)
228 		return;
229 
230 	if ((ptr2 = strrchr(env, ',')) == NULL || ptr2 == env)
231 		return;
232 	for (ptr1 = ptr2 - 1; ptr1 > env && *ptr1 != ','; ptr1--)
233 		;
234 	if (*ptr1 != ',')
235 		return;
236 	ptr1++;
237 	ptr2++;
238 
239 	len = ptr2 - ptr1 - 1;
240 	if (len > (sizeof buf) - 1)
241 		return;
242 	memcpy(buf, ptr1, len);
243 	buf[len] = '\0';
244 
245 	ll = strtonum(buf, 0, LONG_MAX, &errstr);
246 	if (errstr != NULL)
247 		return;
248 	data->pid = ll;
249 
250 	ll = strtonum(ptr2, 0, UINT_MAX, &errstr);
251 	if (errstr != NULL)
252 		return;
253 	data->idx = ll;
254 }
255 
256 char *
257 makesockpath(const char *label)
258 {
259 	char		base[MAXPATHLEN], *path;
260 	struct stat	sb;
261 	u_int		uid;
262 
263 	uid = getuid();
264 	xsnprintf(base, MAXPATHLEN, "%s/tmux-%d", _PATH_TMP, uid);
265 
266 	if (mkdir(base, S_IRWXU) != 0 && errno != EEXIST)
267 		return (NULL);
268 
269 	if (lstat(base, &sb) != 0)
270 		return (NULL);
271 	if (!S_ISDIR(sb.st_mode)) {
272 		errno = ENOTDIR;
273 		return (NULL);
274 	}
275 	if (sb.st_uid != uid || (sb.st_mode & (S_IRWXG|S_IRWXO)) != 0) {
276 		errno = EACCES;
277 		return (NULL);
278 	}
279 
280 	xasprintf(&path, "%s/%s", base, label);
281 	return (path);
282 }
283 
284 int
285 main(int argc, char **argv)
286 {
287 	struct cmd_list		*cmdlist;
288  	struct cmd		*cmd;
289 	struct pollfd		 pfd;
290 	enum msgtype		 msg;
291 	struct passwd		*pw;
292 	struct options		*so, *wo;
293 	struct keylist		*keylist;
294 	struct imsgbuf		*ibuf;
295 	struct msg_command_data	 cmddata;
296 	char			*s, *shellcmd, *path, *label, *home, *cause;
297 	char			 cwd[MAXPATHLEN], **var;
298 	void			*buf;
299 	size_t			 len;
300 	int	 		 nfds, retcode, opt, flags, cmdflags = 0;
301 
302 	flags = 0;
303 	shellcmd = label = path = NULL;
304 	login_shell = (**argv == '-');
305 	while ((opt = getopt(argc, argv, "28c:df:lL:qS:uUv")) != -1) {
306 		switch (opt) {
307 		case '2':
308 			flags |= IDENTIFY_256COLOURS;
309 			flags &= ~IDENTIFY_88COLOURS;
310 			break;
311 		case '8':
312 			flags |= IDENTIFY_88COLOURS;
313 			flags &= ~IDENTIFY_256COLOURS;
314 			break;
315 		case 'c':
316 			if (shellcmd != NULL)
317 				xfree(shellcmd);
318 			shellcmd = xstrdup(optarg);
319 			break;
320 		case 'f':
321 			if (cfg_file != NULL)
322 				xfree(cfg_file);
323 			cfg_file = xstrdup(optarg);
324 			break;
325 		case 'l':
326 			login_shell = 1;
327 			break;
328 		case 'L':
329 			if (label != NULL)
330 				xfree(label);
331 			label = xstrdup(optarg);
332 			break;
333 		case 'q':
334 			be_quiet = 1;
335 			break;
336 		case 'S':
337 			if (path != NULL)
338 				xfree(path);
339 			path = xstrdup(optarg);
340 			break;
341 		case 'u':
342 			flags |= IDENTIFY_UTF8;
343 			break;
344 		case 'v':
345 			debug_level++;
346 			break;
347                 default:
348 			usage();
349                 }
350         }
351 	argc -= optind;
352 	argv += optind;
353 
354 	if (shellcmd != NULL && argc != 0)
355 		usage();
356 
357 	log_open_tty(debug_level);
358 	siginit();
359 
360 	if (!(flags & IDENTIFY_UTF8)) {
361 		/*
362 		 * If the user has set whichever of LC_ALL, LC_CTYPE or LANG
363 		 * exist (in that order) to contain UTF-8, it is a safe
364 		 * assumption that either they are using a UTF-8 terminal, or
365 		 * if not they know that output from UTF-8-capable programs may
366 		 * be wrong.
367 		 */
368 		if ((s = getenv("LC_ALL")) == NULL) {
369 			if ((s = getenv("LC_CTYPE")) == NULL)
370 				s = getenv("LANG");
371 		}
372 		if (s != NULL && (strcasestr(s, "UTF-8") != NULL ||
373 		    strcasestr(s, "UTF8") != NULL))
374 			flags |= IDENTIFY_UTF8;
375 	}
376 
377 	environ_init(&global_environ);
378  	for (var = environ; *var != NULL; var++)
379 		environ_put(&global_environ, *var);
380 
381 	options_init(&global_s_options, NULL);
382 	so = &global_s_options;
383 	options_set_number(so, "base-index", 0);
384 	options_set_number(so, "bell-action", BELL_ANY);
385 	options_set_number(so, "buffer-limit", 9);
386 	options_set_string(so, "default-command", "%s", "");
387 	options_set_string(so, "default-shell", "%s", getshell());
388 	options_set_string(so, "default-terminal", "screen");
389 	options_set_number(so, "display-panes-colour", 4);
390 	options_set_number(so, "display-panes-time", 1000);
391 	options_set_number(so, "display-time", 750);
392 	options_set_number(so, "history-limit", 2000);
393 	options_set_number(so, "lock-after-time", 0);
394 	options_set_string(so, "lock-command", "lock -np");
395 	options_set_number(so, "lock-server", 1);
396 	options_set_number(so, "message-attr", 0);
397 	options_set_number(so, "message-bg", 3);
398 	options_set_number(so, "message-fg", 0);
399 	options_set_number(so, "mouse-select-pane", 0);
400 	options_set_number(so, "repeat-time", 500);
401 	options_set_number(so, "set-remain-on-exit", 0);
402 	options_set_number(so, "set-titles", 0);
403 	options_set_string(so, "set-titles-string", "#S:#I:#W - \"#T\"");
404 	options_set_number(so, "status", 1);
405 	options_set_number(so, "status-attr", 0);
406 	options_set_number(so, "status-bg", 2);
407 	options_set_number(so, "status-fg", 0);
408 	options_set_number(so, "status-interval", 15);
409 	options_set_number(so, "status-justify", 0);
410 	options_set_number(so, "status-keys", MODEKEY_EMACS);
411 	options_set_string(so, "status-left", "[#S]");
412 	options_set_number(so, "status-left-attr", 0);
413 	options_set_number(so, "status-left-bg", 8);
414 	options_set_number(so, "status-left-fg", 8);
415 	options_set_number(so, "status-left-length", 10);
416 	options_set_string(so, "status-right", "\"#22T\" %%H:%%M %%d-%%b-%%y");
417 	options_set_number(so, "status-right-attr", 0);
418 	options_set_number(so, "status-right-bg", 8);
419 	options_set_number(so, "status-right-fg", 8);
420 	options_set_number(so, "status-right-length", 40);
421 	options_set_string(so, "terminal-overrides",
422 	    "*88col*:colors=88,*256col*:colors=256");
423 	options_set_string(so, "update-environment", "DISPLAY "
424 	    "WINDOWID SSH_ASKPASS SSH_AUTH_SOCK SSH_AGENT_PID SSH_CONNECTION");
425 	options_set_number(so, "visual-activity", 0);
426 	options_set_number(so, "visual-bell", 0);
427 	options_set_number(so, "visual-content", 0);
428 
429 	keylist = xmalloc(sizeof *keylist);
430 	ARRAY_INIT(keylist);
431 	ARRAY_ADD(keylist, '\002');
432 	options_set_data(so, "prefix", keylist, xfree);
433 
434 	options_init(&global_w_options, NULL);
435 	wo = &global_w_options;
436 	options_set_number(wo, "aggressive-resize", 0);
437 	options_set_number(wo, "automatic-rename", 1);
438 	options_set_number(wo, "clock-mode-colour", 4);
439 	options_set_number(wo, "clock-mode-style", 1);
440 	options_set_number(wo, "force-height", 0);
441 	options_set_number(wo, "force-width", 0);
442 	options_set_number(wo, "main-pane-height", 24);
443 	options_set_number(wo, "main-pane-width", 81);
444 	options_set_number(wo, "mode-attr", 0);
445 	options_set_number(wo, "mode-bg", 3);
446 	options_set_number(wo, "mode-fg", 0);
447 	options_set_number(wo, "mode-keys", MODEKEY_EMACS);
448 	options_set_number(wo, "mode-mouse", 0);
449 	options_set_number(wo, "monitor-activity", 0);
450 	options_set_string(wo, "monitor-content", "%s", "");
451 	options_set_number(wo, "window-status-attr", 0);
452 	options_set_number(wo, "window-status-bg", 8);
453 	options_set_number(wo, "window-status-current-attr", 0);
454 	options_set_number(wo, "window-status-current-bg", 8);
455 	options_set_number(wo, "window-status-current-fg", 8);
456 	options_set_number(wo, "window-status-fg", 8);
457 	options_set_number(wo, "xterm-keys", 0);
458  	options_set_number(wo, "remain-on-exit", 0);
459 	options_set_number(wo, "synchronize-panes", 0);
460 
461  	if (flags & IDENTIFY_UTF8) {
462 		options_set_number(so, "status-utf8", 1);
463 		options_set_number(wo, "utf8", 1);
464 	} else {
465 		options_set_number(so, "status-utf8", 0);
466 		options_set_number(wo, "utf8", 0);
467 	}
468 
469 	if (getcwd(cwd, sizeof cwd) == NULL) {
470 		pw = getpwuid(getuid());
471 		if (pw->pw_dir != NULL && *pw->pw_dir != '\0')
472 			strlcpy(cwd, pw->pw_dir, sizeof cwd);
473 		else
474 			strlcpy(cwd, "/", sizeof cwd);
475 	}
476 	options_set_string(so, "default-path", "%s", cwd);
477 
478 	if (cfg_file == NULL) {
479 		home = getenv("HOME");
480 		if (home == NULL || *home == '\0') {
481 			pw = getpwuid(getuid());
482 			if (pw != NULL)
483 				home = pw->pw_dir;
484 		}
485 		xasprintf(&cfg_file, "%s/%s", home, DEFAULT_CFG);
486 		if (access(cfg_file, R_OK) != 0) {
487 			xfree(cfg_file);
488 			cfg_file = NULL;
489 		}
490 	} else {
491 		if (access(cfg_file, R_OK) != 0) {
492 			log_warn("%s", cfg_file);
493 			exit(1);
494 		}
495 	}
496 
497 	if (label == NULL)
498 		label = xstrdup("default");
499 	if (path == NULL && (path = makesockpath(label)) == NULL) {
500 		log_warn("can't create socket");
501 		exit(1);
502 	}
503 	xfree(label);
504 
505 	if (shellcmd != NULL) {
506 		msg = MSG_SHELL;
507 		buf = NULL;
508 		len = 0;
509 	} else {
510 		fill_session(&cmddata);
511 
512 		cmddata.argc = argc;
513 		if (cmd_pack_argv(
514 		    argc, argv, cmddata.argv, sizeof cmddata.argv) != 0) {
515 			log_warnx("command too long");
516 			exit(1);
517 		}
518 
519 		msg = MSG_COMMAND;
520 		buf = &cmddata;
521 		len = sizeof cmddata;
522 	}
523 
524 	if (shellcmd != NULL)
525 		cmdflags |= CMD_STARTSERVER;
526 	else if (argc == 0)	/* new-session is the default */
527 		cmdflags |= CMD_STARTSERVER|CMD_SENDENVIRON;
528 	else {
529 		/*
530 		 * It sucks parsing the command string twice (in client and
531 		 * later in server) but it is necessary to get the start server
532 		 * flag.
533 		 */
534 		if ((cmdlist = cmd_list_parse(argc, argv, &cause)) == NULL) {
535 			log_warnx("%s", cause);
536 			exit(1);
537 		}
538 		cmdflags &= ~CMD_STARTSERVER;
539 		TAILQ_FOREACH(cmd, cmdlist, qentry) {
540 			if (cmd->entry->flags & CMD_STARTSERVER)
541 				cmdflags |= CMD_STARTSERVER;
542 			if (cmd->entry->flags & CMD_SENDENVIRON)
543 				cmdflags |= CMD_SENDENVIRON;
544 		}
545 		cmd_list_free(cmdlist);
546 	}
547 
548 	if ((ibuf = client_init(path, cmdflags, flags)) == NULL)
549 		exit(1);
550 	xfree(path);
551 
552  	imsg_compose(ibuf, msg, PROTOCOL_VERSION, -1, -1, buf, len);
553 
554 	retcode = 0;
555 	for (;;) {
556 		pfd.fd = ibuf->fd;
557 		pfd.events = POLLIN;
558 		if (ibuf->w.queued != 0)
559 			pfd.events |= POLLOUT;
560 
561 		if ((nfds = poll(&pfd, 1, INFTIM)) == -1) {
562 			if (errno == EAGAIN || errno == EINTR)
563 				continue;
564 			fatal("poll failed");
565 		}
566 		if (nfds == 0)
567 			continue;
568 
569 		if (pfd.revents & (POLLERR|POLLHUP|POLLNVAL))
570 			fatalx("socket error");
571 
572                 if (pfd.revents & POLLIN) {
573 			if (dispatch_imsg(ibuf, shellcmd, &retcode) != 0)
574 				break;
575 		}
576 
577 		if (pfd.revents & POLLOUT) {
578 			if (msgbuf_write(&ibuf->w) < 0)
579 				fatalx("msgbuf_write failed");
580 		}
581 	}
582 
583 	options_free(&global_s_options);
584 	options_free(&global_w_options);
585 
586 	return (retcode);
587 }
588 
589 int
590 dispatch_imsg(struct imsgbuf *ibuf, const char *shellcmd, int *retcode)
591 {
592 	struct imsg		imsg;
593 	ssize_t			n, datalen;
594 	struct msg_print_data	printdata;
595 	struct msg_shell_data	shelldata;
596 
597         if ((n = imsg_read(ibuf)) == -1 || n == 0)
598 		fatalx("imsg_read failed");
599 
600 	for (;;) {
601 		if ((n = imsg_get(ibuf, &imsg)) == -1)
602 			fatalx("imsg_get failed");
603 		if (n == 0)
604 			return (0);
605 		datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
606 
607 		switch (imsg.hdr.type) {
608 		case MSG_EXIT:
609 		case MSG_SHUTDOWN:
610 			if (datalen != 0)
611 				fatalx("bad MSG_EXIT size");
612 
613 			return (-1);
614 		case MSG_ERROR:
615 			*retcode = 1;
616 			/* FALLTHROUGH */
617 		case MSG_PRINT:
618 			if (datalen != sizeof printdata)
619 				fatalx("bad MSG_PRINT size");
620 			memcpy(&printdata, imsg.data, sizeof printdata);
621 			printdata.msg[(sizeof printdata.msg) - 1] = '\0';
622 
623 			log_info("%s", printdata.msg);
624 			break;
625 		case MSG_READY:
626 			if (datalen != 0)
627 				fatalx("bad MSG_READY size");
628 
629 			client_main();	/* doesn't return */
630 		case MSG_VERSION:
631 			if (datalen != 0)
632 				fatalx("bad MSG_VERSION size");
633 
634 			log_warnx("protocol version mismatch (client %u, "
635 			    "server %u)", PROTOCOL_VERSION, imsg.hdr.peerid);
636 			*retcode = 1;
637 			return (-1);
638 		case MSG_SHELL:
639 			if (datalen != sizeof shelldata)
640 				fatalx("bad MSG_SHELL size");
641 			memcpy(&shelldata, imsg.data, sizeof shelldata);
642 			shelldata.shell[(sizeof shelldata.shell) - 1] = '\0';
643 
644 			shell_exec(shelldata.shell, shellcmd);
645 		default:
646 			fatalx("unexpected message");
647 		}
648 
649 		imsg_free(&imsg);
650 	}
651 }
652 
653 __dead void
654 shell_exec(const char *shell, const char *shellcmd)
655 {
656 	const char	*shellname, *ptr;
657 	char		*argv0;
658 
659 	sigreset();
660 
661 	ptr = strrchr(shell, '/');
662 	if (ptr != NULL && *(ptr + 1) != '\0')
663 		shellname = ptr + 1;
664 	else
665 		shellname = shell;
666 	if (login_shell)
667 		xasprintf(&argv0, "-%s", shellname);
668 	else
669 		xasprintf(&argv0, "%s", shellname);
670 	setenv("SHELL", shell, 1);
671 
672 	execl(shell, argv0, "-c", shellcmd, (char *) NULL);
673 	fatal("execl failed");
674 }
675