tmux.c revision 1.196 
1/* $OpenBSD: tmux.c,v 1.196 2020/04/09 15:35:27 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 <stdlib.h>
32#include <string.h>
33#include <time.h>
34#include <unistd.h>
35#include <util.h>
36
37#include "tmux.h"
38
39struct options	*global_options;	/* server options */
40struct options	*global_s_options;	/* session options */
41struct options	*global_w_options;	/* window options */
42struct environ	*global_environ;
43
44struct timeval	 start_time;
45const char	*socket_path;
46int		 ptm_fd = -1;
47const char	*shell_command;
48
49static __dead void	 usage(void);
50static char		*make_label(const char *, char **);
51
52static int		 areshell(const char *);
53static const char	*getshell(void);
54
55static __dead void
56usage(void)
57{
58	fprintf(stderr,
59	    "usage: %s [-2CluvV] [-c shell-command] [-f file] [-L socket-name]\n"
60	    "            [-S socket-path] [command [flags]]\n",
61	    getprogname());
62	exit(1);
63}
64
65static const char *
66getshell(void)
67{
68	struct passwd	*pw;
69	const char	*shell;
70
71	shell = getenv("SHELL");
72	if (checkshell(shell))
73		return (shell);
74
75	pw = getpwuid(getuid());
76	if (pw != NULL && checkshell(pw->pw_shell))
77		return (pw->pw_shell);
78
79	return (_PATH_BSHELL);
80}
81
82int
83checkshell(const char *shell)
84{
85	if (shell == NULL || *shell != '/')
86		return (0);
87	if (areshell(shell))
88		return (0);
89	if (access(shell, X_OK) != 0)
90		return (0);
91	return (1);
92}
93
94static int
95areshell(const char *shell)
96{
97	const char	*progname, *ptr;
98
99	if ((ptr = strrchr(shell, '/')) != NULL)
100		ptr++;
101	else
102		ptr = shell;
103	progname = getprogname();
104	if (*progname == '-')
105		progname++;
106	if (strcmp(ptr, progname) == 0)
107		return (1);
108	return (0);
109}
110
111static char *
112make_label(const char *label, char **cause)
113{
114	char		*base, resolved[PATH_MAX], *path, *s;
115	struct stat	 sb;
116	uid_t		 uid;
117
118	*cause = NULL;
119
120	if (label == NULL)
121		label = "default";
122	uid = getuid();
123
124	if ((s = getenv("TMUX_TMPDIR")) != NULL && *s != '\0')
125		xasprintf(&base, "%s/tmux-%ld", s, (long)uid);
126	else
127		xasprintf(&base, "%s/tmux-%ld", _PATH_TMP, (long)uid);
128	if (realpath(base, resolved) == NULL &&
129	    strlcpy(resolved, base, sizeof resolved) >= sizeof resolved) {
130		errno = ERANGE;
131		free(base);
132		goto fail;
133	}
134	free(base);
135
136	if (mkdir(resolved, S_IRWXU) != 0 && errno != EEXIST)
137		goto fail;
138	if (lstat(resolved, &sb) != 0)
139		goto fail;
140	if (!S_ISDIR(sb.st_mode)) {
141		errno = ENOTDIR;
142		goto fail;
143	}
144	if (sb.st_uid != uid || (sb.st_mode & S_IRWXO) != 0) {
145		errno = EACCES;
146		goto fail;
147	}
148	xasprintf(&path, "%s/%s", resolved, label);
149	return (path);
150
151fail:
152	xasprintf(cause, "error creating %s (%s)", resolved, strerror(errno));
153	return (NULL);
154}
155
156void
157setblocking(int fd, int state)
158{
159	int mode;
160
161	if ((mode = fcntl(fd, F_GETFL)) != -1) {
162		if (!state)
163			mode |= O_NONBLOCK;
164		else
165			mode &= ~O_NONBLOCK;
166		fcntl(fd, F_SETFL, mode);
167	}
168}
169
170const char *
171find_cwd(void)
172{
173	char		 resolved1[PATH_MAX], resolved2[PATH_MAX];
174	static char	 cwd[PATH_MAX];
175	const char	*pwd;
176
177	if (getcwd(cwd, sizeof cwd) == NULL)
178		return (NULL);
179	if ((pwd = getenv("PWD")) == NULL || *pwd == '\0')
180		return (cwd);
181
182	/*
183	 * We want to use PWD so that symbolic links are maintained,
184	 * but only if it matches the actual working directory.
185	 */
186	if (realpath(pwd, resolved1) == NULL)
187		return (cwd);
188	if (realpath(cwd, resolved2) == NULL)
189		return (cwd);
190	if (strcmp(resolved1, resolved2) != 0)
191		return (cwd);
192	return (pwd);
193}
194
195const char *
196find_home(void)
197{
198	struct passwd		*pw;
199	static const char	*home;
200
201	if (home != NULL)
202		return (home);
203
204	home = getenv("HOME");
205	if (home == NULL || *home == '\0') {
206		pw = getpwuid(getuid());
207		if (pw != NULL)
208			home = pw->pw_dir;
209		else
210			home = NULL;
211	}
212
213	return (home);
214}
215
216const char *
217getversion(void)
218{
219	static char	*version;
220	struct utsname	 u;
221
222	if (version == NULL) {
223		if (uname(&u) < 0)
224			fatalx("uname failed");
225		xasprintf(&version, "openbsd-%s", u.release);
226	}
227	return (version);
228}
229
230int
231main(int argc, char **argv)
232{
233	char					*path, *label, *cause, **var;
234	const char				*s, *shell, *cwd;
235	int					 opt, flags, keys;
236	const struct options_table_entry	*oe;
237
238	if (setlocale(LC_CTYPE, "en_US.UTF-8") == NULL &&
239	    setlocale(LC_CTYPE, "C.UTF-8") == NULL) {
240		if (setlocale(LC_CTYPE, "") == NULL)
241			errx(1, "invalid LC_ALL, LC_CTYPE or LANG");
242		s = nl_langinfo(CODESET);
243		if (strcasecmp(s, "UTF-8") != 0 && strcasecmp(s, "UTF8") != 0)
244			errx(1, "need UTF-8 locale (LC_CTYPE) but have %s", s);
245	}
246
247	setlocale(LC_TIME, "");
248	tzset();
249
250	if (**argv == '-')
251		flags = CLIENT_LOGIN;
252	else
253		flags = 0;
254
255	label = path = NULL;
256	while ((opt = getopt(argc, argv, "2c:Cdf:lL:qS:uUvV")) != -1) {
257		switch (opt) {
258		case '2':
259			flags |= CLIENT_256COLOURS;
260			break;
261		case 'c':
262			shell_command = optarg;
263			break;
264		case 'C':
265			if (flags & CLIENT_CONTROL)
266				flags |= CLIENT_CONTROLCONTROL;
267			else
268				flags |= CLIENT_CONTROL;
269			break;
270		case 'f':
271			set_cfg_file(optarg);
272			break;
273 		case 'V':
274			printf("%s %s\n", getprogname(), getversion());
275 			exit(0);
276		case 'l':
277			flags |= CLIENT_LOGIN;
278			break;
279		case 'L':
280			free(label);
281			label = xstrdup(optarg);
282			break;
283		case 'q':
284			break;
285		case 'S':
286			free(path);
287			path = xstrdup(optarg);
288			break;
289		case 'u':
290			flags |= CLIENT_UTF8;
291			break;
292		case 'v':
293			log_add_level();
294			break;
295		default:
296			usage();
297		}
298	}
299	argc -= optind;
300	argv += optind;
301
302	if (shell_command != NULL && argc != 0)
303		usage();
304
305	if ((ptm_fd = getptmfd()) == -1)
306		err(1, "getptmfd");
307	if (pledge("stdio rpath wpath cpath flock fattr unix getpw sendfd "
308	    "recvfd proc exec tty ps", NULL) != 0)
309		err(1, "pledge");
310
311	/*
312	 * tmux is a UTF-8 terminal, so if TMUX is set, assume UTF-8.
313	 * Otherwise, if the user has set LC_ALL, LC_CTYPE or LANG to contain
314	 * UTF-8, it is a safe assumption that either they are using a UTF-8
315	 * terminal, or if not they know that output from UTF-8-capable
316	 * programs may be wrong.
317	 */
318	if (getenv("TMUX") != NULL)
319		flags |= CLIENT_UTF8;
320	else {
321		s = getenv("LC_ALL");
322		if (s == NULL || *s == '\0')
323			s = getenv("LC_CTYPE");
324		if (s == NULL || *s == '\0')
325			s = getenv("LANG");
326		if (s == NULL || *s == '\0')
327			s = "";
328		if (strcasestr(s, "UTF-8") != NULL ||
329		    strcasestr(s, "UTF8") != NULL)
330			flags |= CLIENT_UTF8;
331	}
332
333	global_environ = environ_create();
334	for (var = environ; *var != NULL; var++)
335		environ_put(global_environ, *var, 0);
336	if ((cwd = find_cwd()) != NULL)
337		environ_set(global_environ, "PWD", 0, "%s", cwd);
338
339	global_options = options_create(NULL);
340	global_s_options = options_create(NULL);
341	global_w_options = options_create(NULL);
342	for (oe = options_table; oe->name != NULL; oe++) {
343		if (oe->scope & OPTIONS_TABLE_SERVER)
344			options_default(global_options, oe);
345		if (oe->scope & OPTIONS_TABLE_SESSION)
346			options_default(global_s_options, oe);
347		if (oe->scope & OPTIONS_TABLE_WINDOW)
348			options_default(global_w_options, oe);
349	}
350
351	/*
352	 * The default shell comes from SHELL or from the user's passwd entry
353	 * if available.
354	 */
355	shell = getshell();
356	options_set_string(global_s_options, "default-shell", 0, "%s", shell);
357
358	/* Override keys to vi if VISUAL or EDITOR are set. */
359	if ((s = getenv("VISUAL")) != NULL || (s = getenv("EDITOR")) != NULL) {
360		if (strrchr(s, '/') != NULL)
361			s = strrchr(s, '/') + 1;
362		if (strstr(s, "vi") != NULL)
363			keys = MODEKEY_VI;
364		else
365			keys = MODEKEY_EMACS;
366		options_set_number(global_s_options, "status-keys", keys);
367		options_set_number(global_w_options, "mode-keys", keys);
368	}
369
370	/*
371	 * If socket is specified on the command-line with -S or -L, it is
372	 * used. Otherwise, $TMUX is checked and if that fails "default" is
373	 * used.
374	 */
375	if (path == NULL && label == NULL) {
376		s = getenv("TMUX");
377		if (s != NULL && *s != '\0' && *s != ',') {
378			path = xstrdup(s);
379			path[strcspn(path, ",")] = '\0';
380		}
381	}
382	if (path == NULL) {
383		if ((path = make_label(label, &cause)) == NULL) {
384			if (cause != NULL) {
385				fprintf(stderr, "%s\n", cause);
386				free(cause);
387			}
388			exit(1);
389		}
390		flags |= CLIENT_DEFAULTSOCKET;
391	}
392	socket_path = path;
393	free(label);
394
395	/* Pass control to the client. */
396	exit(client_main(event_init(), argc, argv, flags));
397}
398