tmux.c revision 1.212 
1/* $OpenBSD: tmux.c,v 1.212 2024/05/15 09:59:12 nicm Exp $ */
2
3/*
4 * Copyright (c) 2007 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#include <sys/stat.h>
21#include <sys/utsname.h>
22
23#include <err.h>
24#include <errno.h>
25#include <event.h>
26#include <fcntl.h>
27#include <langinfo.h>
28#include <locale.h>
29#include <paths.h>
30#include <pwd.h>
31#include <signal.h>
32#include <stdlib.h>
33#include <string.h>
34#include <time.h>
35#include <unistd.h>
36#include <util.h>
37
38#include "tmux.h"
39
40struct options	*global_options;	/* server options */
41struct options	*global_s_options;	/* session options */
42struct options	*global_w_options;	/* window options */
43struct environ	*global_environ;
44
45struct timeval	 start_time;
46const char	*socket_path;
47int		 ptm_fd = -1;
48const char	*shell_command;
49
50static __dead void	 usage(void);
51static char		*make_label(const char *, char **);
52
53static int		 areshell(const char *);
54static const char	*getshell(void);
55
56static __dead void
57usage(void)
58{
59	fprintf(stderr,
60	    "usage: %s [-2CDlNuVv] [-c shell-command] [-f file] [-L socket-name]\n"
61	    "            [-S socket-path] [-T features] [command [flags]]\n",
62	    getprogname());
63	exit(1);
64}
65
66static const char *
67getshell(void)
68{
69	struct passwd	*pw;
70	const char	*shell;
71
72	shell = getenv("SHELL");
73	if (checkshell(shell))
74		return (shell);
75
76	pw = getpwuid(getuid());
77	if (pw != NULL && checkshell(pw->pw_shell))
78		return (pw->pw_shell);
79
80	return (_PATH_BSHELL);
81}
82
83int
84checkshell(const char *shell)
85{
86	if (shell == NULL || *shell != '/')
87		return (0);
88	if (areshell(shell))
89		return (0);
90	if (access(shell, X_OK) != 0)
91		return (0);
92	return (1);
93}
94
95static int
96areshell(const char *shell)
97{
98	const char	*progname, *ptr;
99
100	if ((ptr = strrchr(shell, '/')) != NULL)
101		ptr++;
102	else
103		ptr = shell;
104	progname = getprogname();
105	if (*progname == '-')
106		progname++;
107	if (strcmp(ptr, progname) == 0)
108		return (1);
109	return (0);
110}
111
112static char *
113expand_path(const char *path, const char *home)
114{
115	char			*expanded, *name;
116	const char		*end;
117	struct environ_entry	*value;
118
119	if (strncmp(path, "~/", 2) == 0) {
120		if (home == NULL)
121			return (NULL);
122		xasprintf(&expanded, "%s%s", home, path + 1);
123		return (expanded);
124	}
125
126	if (*path == '$') {
127		end = strchr(path, '/');
128		if (end == NULL)
129			name = xstrdup(path + 1);
130		else
131			name = xstrndup(path + 1, end - path - 1);
132		value = environ_find(global_environ, name);
133		free(name);
134		if (value == NULL)
135			return (NULL);
136		if (end == NULL)
137			end = "";
138		xasprintf(&expanded, "%s%s", value->value, end);
139		return (expanded);
140	}
141
142	return (xstrdup(path));
143}
144
145static void
146expand_paths(const char *s, char ***paths, u_int *n, int ignore_errors)
147{
148	const char	*home = find_home();
149	char		*copy, *next, *tmp, resolved[PATH_MAX], *expanded;
150	char		*path;
151	u_int		 i;
152
153	*paths = NULL;
154	*n = 0;
155
156	copy = tmp = xstrdup(s);
157	while ((next = strsep(&tmp, ":")) != NULL) {
158		expanded = expand_path(next, home);
159		if (expanded == NULL) {
160			log_debug("%s: invalid path: %s", __func__, next);
161			continue;
162		}
163		if (realpath(expanded, resolved) == NULL) {
164			log_debug("%s: realpath(\"%s\") failed: %s", __func__,
165			    expanded, strerror(errno));
166			if (ignore_errors) {
167				free(expanded);
168				continue;
169			}
170			path = expanded;
171		} else {
172			path = xstrdup(resolved);
173			free(expanded);
174		}
175		for (i = 0; i < *n; i++) {
176			if (strcmp(path, (*paths)[i]) == 0)
177				break;
178		}
179		if (i != *n) {
180			log_debug("%s: duplicate path: %s", __func__, path);
181			free(path);
182			continue;
183		}
184		*paths = xreallocarray(*paths, (*n) + 1, sizeof *paths);
185		(*paths)[(*n)++] = path;
186	}
187	free(copy);
188}
189
190static char *
191make_label(const char *label, char **cause)
192{
193	char		**paths, *path, *base;
194	u_int		  i, n;
195	struct stat	  sb;
196	uid_t		  uid;
197
198	*cause = NULL;
199	if (label == NULL)
200		label = "default";
201	uid = getuid();
202
203	expand_paths(TMUX_SOCK, &paths, &n, 1);
204	if (n == 0) {
205		xasprintf(cause, "no suitable socket path");
206		return (NULL);
207	}
208	path = paths[0]; /* can only have one socket! */
209	for (i = 1; i < n; i++)
210		free(paths[i]);
211	free(paths);
212
213	xasprintf(&base, "%s/tmux-%ld", path, (long)uid);
214	free(path);
215	if (mkdir(base, S_IRWXU) != 0 && errno != EEXIST) {
216		xasprintf(cause, "couldn't create directory %s (%s)", base,
217		    strerror(errno));
218		goto fail;
219	}
220	if (lstat(base, &sb) != 0) {
221		xasprintf(cause, "couldn't read directory %s (%s)", base,
222		    strerror(errno));
223		goto fail;
224	}
225	if (!S_ISDIR(sb.st_mode)) {
226		xasprintf(cause, "%s is not a directory", base);
227		goto fail;
228	}
229	if (sb.st_uid != uid || (sb.st_mode & S_IRWXO) != 0) {
230		xasprintf(cause, "directory %s has unsafe permissions", base);
231		goto fail;
232	}
233	xasprintf(&path, "%s/%s", base, label);
234	free(base);
235	return (path);
236
237fail:
238	free(base);
239	return (NULL);
240}
241
242char *
243shell_argv0(const char *shell, int is_login)
244{
245	const char	*slash, *name;
246	char		*argv0;
247
248	slash = strrchr(shell, '/');
249	if (slash != NULL && slash[1] != '\0')
250		name = slash + 1;
251	else
252		name = shell;
253	if (is_login)
254		xasprintf(&argv0, "-%s", name);
255	else
256		xasprintf(&argv0, "%s", name);
257	return (argv0);
258}
259
260void
261setblocking(int fd, int state)
262{
263	int mode;
264
265	if ((mode = fcntl(fd, F_GETFL)) != -1) {
266		if (!state)
267			mode |= O_NONBLOCK;
268		else
269			mode &= ~O_NONBLOCK;
270		fcntl(fd, F_SETFL, mode);
271	}
272}
273
274uint64_t
275get_timer(void)
276{
277	struct timespec	ts;
278
279	/*
280	 * We want a timestamp in milliseconds suitable for time measurement,
281	 * so prefer the monotonic clock.
282	 */
283	if (clock_gettime(CLOCK_MONOTONIC, &ts) != 0)
284		clock_gettime(CLOCK_REALTIME, &ts);
285	return ((ts.tv_sec * 1000ULL) + (ts.tv_nsec / 1000000ULL));
286}
287
288const char *
289sig2name(int signo)
290{
291     static char	s[11];
292
293     if (signo > 0 && signo < NSIG)
294	     return (sys_signame[signo]);
295     xsnprintf(s, sizeof s, "%d", signo);
296     return (s);
297}
298
299const char *
300find_cwd(void)
301{
302	char		 resolved1[PATH_MAX], resolved2[PATH_MAX];
303	static char	 cwd[PATH_MAX];
304	const char	*pwd;
305
306	if (getcwd(cwd, sizeof cwd) == NULL)
307		return (NULL);
308	if ((pwd = getenv("PWD")) == NULL || *pwd == '\0')
309		return (cwd);
310
311	/*
312	 * We want to use PWD so that symbolic links are maintained,
313	 * but only if it matches the actual working directory.
314	 */
315	if (realpath(pwd, resolved1) == NULL)
316		return (cwd);
317	if (realpath(cwd, resolved2) == NULL)
318		return (cwd);
319	if (strcmp(resolved1, resolved2) != 0)
320		return (cwd);
321	return (pwd);
322}
323
324const char *
325find_home(void)
326{
327	struct passwd		*pw;
328	static const char	*home;
329
330	if (home != NULL)
331		return (home);
332
333	home = getenv("HOME");
334	if (home == NULL || *home == '\0') {
335		pw = getpwuid(getuid());
336		if (pw != NULL)
337			home = pw->pw_dir;
338		else
339			home = NULL;
340	}
341
342	return (home);
343}
344
345const char *
346getversion(void)
347{
348	static char	*version;
349	struct utsname	 u;
350
351	if (version == NULL) {
352		if (uname(&u) < 0)
353			fatalx("uname failed");
354		xasprintf(&version, "openbsd-%s", u.release);
355	}
356	return (version);
357}
358
359int
360main(int argc, char **argv)
361{
362	char					*path = NULL, *label = NULL;
363	char					*cause, **var;
364	const char				*s, *cwd;
365	int					 opt, keys, feat = 0, fflag = 0;
366	uint64_t				 flags = 0;
367	const struct options_table_entry	*oe;
368	u_int					 i;
369
370	if (setlocale(LC_CTYPE, "en_US.UTF-8") == NULL &&
371	    setlocale(LC_CTYPE, "C.UTF-8") == NULL) {
372		if (setlocale(LC_CTYPE, "") == NULL)
373			errx(1, "invalid LC_ALL, LC_CTYPE or LANG");
374		s = nl_langinfo(CODESET);
375		if (strcasecmp(s, "UTF-8") != 0 && strcasecmp(s, "UTF8") != 0)
376			errx(1, "need UTF-8 locale (LC_CTYPE) but have %s", s);
377	}
378
379	setlocale(LC_TIME, "");
380	tzset();
381
382	if (**argv == '-')
383		flags = CLIENT_LOGIN;
384
385	global_environ = environ_create();
386	for (var = environ; *var != NULL; var++)
387		environ_put(global_environ, *var, 0);
388	if ((cwd = find_cwd()) != NULL)
389		environ_set(global_environ, "PWD", 0, "%s", cwd);
390	expand_paths(TMUX_CONF, &cfg_files, &cfg_nfiles, 1);
391
392	while ((opt = getopt(argc, argv, "2c:CDdf:lL:NqS:T:uUvV")) != -1) {
393		switch (opt) {
394		case '2':
395			tty_add_features(&feat, "256", ":,");
396			break;
397		case 'c':
398			shell_command = optarg;
399			break;
400		case 'D':
401			flags |= CLIENT_NOFORK;
402			break;
403		case 'C':
404			if (flags & CLIENT_CONTROL)
405				flags |= CLIENT_CONTROLCONTROL;
406			else
407				flags |= CLIENT_CONTROL;
408			break;
409		case 'f':
410			if (!fflag) {
411				fflag = 1;
412				for (i = 0; i < cfg_nfiles; i++)
413					free(cfg_files[i]);
414				cfg_nfiles = 0;
415			}
416			cfg_files = xreallocarray(cfg_files, cfg_nfiles + 1,
417			    sizeof *cfg_files);
418			cfg_files[cfg_nfiles++] = xstrdup(optarg);
419			cfg_quiet = 0;
420			break;
421 		case 'V':
422			printf("tmux %s\n", getversion());
423 			exit(0);
424		case 'l':
425			flags |= CLIENT_LOGIN;
426			break;
427		case 'L':
428			free(label);
429			label = xstrdup(optarg);
430			break;
431		case 'N':
432			flags |= CLIENT_NOSTARTSERVER;
433			break;
434		case 'q':
435			break;
436		case 'S':
437			free(path);
438			path = xstrdup(optarg);
439			break;
440		case 'T':
441			tty_add_features(&feat, optarg, ":,");
442			break;
443		case 'u':
444			flags |= CLIENT_UTF8;
445			break;
446		case 'v':
447			log_add_level();
448			break;
449		default:
450			usage();
451		}
452	}
453	argc -= optind;
454	argv += optind;
455
456	if (shell_command != NULL && argc != 0)
457		usage();
458	if ((flags & CLIENT_NOFORK) && argc != 0)
459		usage();
460
461	if ((ptm_fd = getptmfd()) == -1)
462		err(1, "getptmfd");
463	if (pledge("stdio rpath wpath cpath flock fattr unix getpw sendfd "
464	    "recvfd proc exec tty ps", NULL) != 0)
465		err(1, "pledge");
466
467	/*
468	 * tmux is a UTF-8 terminal, so if TMUX is set, assume UTF-8.
469	 * Otherwise, if the user has set LC_ALL, LC_CTYPE or LANG to contain
470	 * UTF-8, it is a safe assumption that either they are using a UTF-8
471	 * terminal, or if not they know that output from UTF-8-capable
472	 * programs may be wrong.
473	 */
474	if (getenv("TMUX") != NULL)
475		flags |= CLIENT_UTF8;
476	else {
477		s = getenv("LC_ALL");
478		if (s == NULL || *s == '\0')
479			s = getenv("LC_CTYPE");
480		if (s == NULL || *s == '\0')
481			s = getenv("LANG");
482		if (s == NULL || *s == '\0')
483			s = "";
484		if (strcasestr(s, "UTF-8") != NULL ||
485		    strcasestr(s, "UTF8") != NULL)
486			flags |= CLIENT_UTF8;
487	}
488
489	global_options = options_create(NULL);
490	global_s_options = options_create(NULL);
491	global_w_options = options_create(NULL);
492	for (oe = options_table; oe->name != NULL; oe++) {
493		if (oe->scope & OPTIONS_TABLE_SERVER)
494			options_default(global_options, oe);
495		if (oe->scope & OPTIONS_TABLE_SESSION)
496			options_default(global_s_options, oe);
497		if (oe->scope & OPTIONS_TABLE_WINDOW)
498			options_default(global_w_options, oe);
499	}
500
501	/*
502	 * The default shell comes from SHELL or from the user's passwd entry
503	 * if available.
504	 */
505	options_set_string(global_s_options, "default-shell", 0, "%s",
506	    getshell());
507
508	/* Override keys to vi if VISUAL or EDITOR are set. */
509	if ((s = getenv("VISUAL")) != NULL || (s = getenv("EDITOR")) != NULL) {
510		options_set_string(global_options, "editor", 0, "%s", s);
511		if (strrchr(s, '/') != NULL)
512			s = strrchr(s, '/') + 1;
513		if (strstr(s, "vi") != NULL)
514			keys = MODEKEY_VI;
515		else
516			keys = MODEKEY_EMACS;
517		options_set_number(global_s_options, "status-keys", keys);
518		options_set_number(global_w_options, "mode-keys", keys);
519	}
520
521	/*
522	 * If socket is specified on the command-line with -S or -L, it is
523	 * used. Otherwise, $TMUX is checked and if that fails "default" is
524	 * used.
525	 */
526	if (path == NULL && label == NULL) {
527		s = getenv("TMUX");
528		if (s != NULL && *s != '\0' && *s != ',') {
529			path = xstrdup(s);
530			path[strcspn(path, ",")] = '\0';
531		}
532	}
533	if (path == NULL) {
534		if ((path = make_label(label, &cause)) == NULL) {
535			if (cause != NULL) {
536				fprintf(stderr, "%s\n", cause);
537				free(cause);
538			}
539			exit(1);
540		}
541		flags |= CLIENT_DEFAULTSOCKET;
542	}
543	socket_path = path;
544	free(label);
545
546	/* Pass control to the client. */
547	exit(client_main(event_init(), argc, argv, flags, feat));
548}
549