xref: /freebsd/bin/sh/cd.c (revision 6472ac3d8a86336899b6cfb789a4cd9897e3fab5)
1 /*-
2  * Copyright (c) 1991, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * This code is derived from software contributed to Berkeley by
6  * Kenneth Almquist.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  * 4. Neither the name of the University nor the names of its contributors
17  *    may be used to endorse or promote products derived from this software
18  *    without specific prior written permission.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30  * SUCH DAMAGE.
31  */
32 
33 #ifndef lint
34 #if 0
35 static char sccsid[] = "@(#)cd.c	8.2 (Berkeley) 5/4/95";
36 #endif
37 #endif /* not lint */
38 #include <sys/cdefs.h>
39 __FBSDID("$FreeBSD$");
40 
41 #include <sys/types.h>
42 #include <sys/stat.h>
43 #include <stdlib.h>
44 #include <string.h>
45 #include <unistd.h>
46 #include <errno.h>
47 #include <limits.h>
48 
49 /*
50  * The cd and pwd commands.
51  */
52 
53 #include "shell.h"
54 #include "var.h"
55 #include "nodes.h"	/* for jobs.h */
56 #include "jobs.h"
57 #include "options.h"
58 #include "output.h"
59 #include "memalloc.h"
60 #include "error.h"
61 #include "exec.h"
62 #include "redir.h"
63 #include "mystring.h"
64 #include "show.h"
65 #include "cd.h"
66 #include "builtins.h"
67 
68 static int cdlogical(char *);
69 static int cdphysical(char *);
70 static int docd(char *, int, int);
71 static char *getcomponent(void);
72 static char *findcwd(char *);
73 static void updatepwd(char *);
74 static char *getpwd(void);
75 static char *getpwd2(void);
76 
77 static char *curdir = NULL;	/* current working directory */
78 static char *prevdir;		/* previous working directory */
79 static char *cdcomppath;
80 
81 int
82 cdcmd(int argc, char **argv)
83 {
84 	const char *dest;
85 	const char *path;
86 	char *p;
87 	struct stat statb;
88 	int ch, phys, print = 0, getcwderr = 0;
89 	int rc;
90 	int errno1 = ENOENT;
91 
92 	optreset = 1; optind = 1; opterr = 0; /* initialize getopt */
93 	phys = Pflag;
94 	while ((ch = getopt(argc, argv, "eLP")) != -1) {
95 		switch (ch) {
96 		case 'e':
97 			getcwderr = 1;
98 			break;
99 		case 'L':
100 			phys = 0;
101 			break;
102 		case 'P':
103 			phys = 1;
104 			break;
105 		default:
106 			error("unknown option: -%c", optopt);
107 			break;
108 		}
109 	}
110 	argc -= optind;
111 	argv += optind;
112 
113 	if (argc > 1)
114 		error("too many arguments");
115 
116 	if ((dest = *argv) == NULL && (dest = bltinlookup("HOME", 1)) == NULL)
117 		error("HOME not set");
118 	if (*dest == '\0')
119 		dest = ".";
120 	if (dest[0] == '-' && dest[1] == '\0') {
121 		dest = prevdir ? prevdir : curdir;
122 		if (dest)
123 			print = 1;
124 		else
125 			dest = ".";
126 	}
127 	if (dest[0] == '/' ||
128 	    (dest[0] == '.' && (dest[1] == '/' || dest[1] == '\0')) ||
129 	    (dest[0] == '.' && dest[1] == '.' && (dest[2] == '/' || dest[2] == '\0')) ||
130 	    (path = bltinlookup("CDPATH", 1)) == NULL)
131 		path = nullstr;
132 	while ((p = padvance(&path, dest)) != NULL) {
133 		if (stat(p, &statb) >= 0 && S_ISDIR(statb.st_mode)) {
134 			if (!print) {
135 				/*
136 				 * XXX - rethink
137 				 */
138 				if (p[0] == '.' && p[1] == '/' && p[2] != '\0')
139 					print = strcmp(p + 2, dest);
140 				else
141 					print = strcmp(p, dest);
142 			}
143 			rc = docd(p, print, phys);
144 			if (rc >= 0)
145 				return getcwderr ? rc : 0;
146 			if (errno != ENOENT)
147 				errno1 = errno;
148 		}
149 	}
150 	error("%s: %s", dest, strerror(errno1));
151 	/*NOTREACHED*/
152 	return 0;
153 }
154 
155 
156 /*
157  * Actually change the directory.  In an interactive shell, print the
158  * directory name if "print" is nonzero.
159  */
160 static int
161 docd(char *dest, int print, int phys)
162 {
163 	int rc;
164 
165 	TRACE(("docd(\"%s\", %d, %d) called\n", dest, print, phys));
166 
167 	/* If logical cd fails, fall back to physical. */
168 	if ((phys || (rc = cdlogical(dest)) < 0) && (rc = cdphysical(dest)) < 0)
169 		return (-1);
170 
171 	if (print && iflag && curdir)
172 		out1fmt("%s\n", curdir);
173 
174 	return (rc);
175 }
176 
177 static int
178 cdlogical(char *dest)
179 {
180 	char *p;
181 	char *q;
182 	char *component;
183 	struct stat statb;
184 	int first;
185 	int badstat;
186 
187 	/*
188 	 *  Check each component of the path. If we find a symlink or
189 	 *  something we can't stat, clear curdir to force a getcwd()
190 	 *  next time we get the value of the current directory.
191 	 */
192 	badstat = 0;
193 	cdcomppath = stalloc(strlen(dest) + 1);
194 	scopy(dest, cdcomppath);
195 	STARTSTACKSTR(p);
196 	if (*dest == '/') {
197 		STPUTC('/', p);
198 		cdcomppath++;
199 	}
200 	first = 1;
201 	while ((q = getcomponent()) != NULL) {
202 		if (q[0] == '\0' || (q[0] == '.' && q[1] == '\0'))
203 			continue;
204 		if (! first)
205 			STPUTC('/', p);
206 		first = 0;
207 		component = q;
208 		STPUTS(q, p);
209 		if (equal(component, ".."))
210 			continue;
211 		STACKSTRNUL(p);
212 		if (lstat(stackblock(), &statb) < 0) {
213 			badstat = 1;
214 			break;
215 		}
216 	}
217 
218 	INTOFF;
219 	if ((p = findcwd(badstat ? NULL : dest)) == NULL || chdir(p) < 0) {
220 		INTON;
221 		return (-1);
222 	}
223 	updatepwd(p);
224 	INTON;
225 	return (0);
226 }
227 
228 static int
229 cdphysical(char *dest)
230 {
231 	char *p;
232 	int rc = 0;
233 
234 	INTOFF;
235 	if (chdir(dest) < 0) {
236 		INTON;
237 		return (-1);
238 	}
239 	p = findcwd(NULL);
240 	if (p == NULL) {
241 		warning("warning: failed to get name of current directory");
242 		rc = 1;
243 	}
244 	updatepwd(p);
245 	INTON;
246 	return (rc);
247 }
248 
249 /*
250  * Get the next component of the path name pointed to by cdcomppath.
251  * This routine overwrites the string pointed to by cdcomppath.
252  */
253 static char *
254 getcomponent(void)
255 {
256 	char *p;
257 	char *start;
258 
259 	if ((p = cdcomppath) == NULL)
260 		return NULL;
261 	start = cdcomppath;
262 	while (*p != '/' && *p != '\0')
263 		p++;
264 	if (*p == '\0') {
265 		cdcomppath = NULL;
266 	} else {
267 		*p++ = '\0';
268 		cdcomppath = p;
269 	}
270 	return start;
271 }
272 
273 
274 static char *
275 findcwd(char *dir)
276 {
277 	char *new;
278 	char *p;
279 
280 	/*
281 	 * If our argument is NULL, we don't know the current directory
282 	 * any more because we traversed a symbolic link or something
283 	 * we couldn't stat().
284 	 */
285 	if (dir == NULL || curdir == NULL)
286 		return getpwd2();
287 	cdcomppath = stalloc(strlen(dir) + 1);
288 	scopy(dir, cdcomppath);
289 	STARTSTACKSTR(new);
290 	if (*dir != '/') {
291 		STPUTS(curdir, new);
292 		if (STTOPC(new) == '/')
293 			STUNPUTC(new);
294 	}
295 	while ((p = getcomponent()) != NULL) {
296 		if (equal(p, "..")) {
297 			while (new > stackblock() && (STUNPUTC(new), *new) != '/');
298 		} else if (*p != '\0' && ! equal(p, ".")) {
299 			STPUTC('/', new);
300 			STPUTS(p, new);
301 		}
302 	}
303 	if (new == stackblock())
304 		STPUTC('/', new);
305 	STACKSTRNUL(new);
306 	return stackblock();
307 }
308 
309 /*
310  * Update curdir (the name of the current directory) in response to a
311  * cd command.  We also call hashcd to let the routines in exec.c know
312  * that the current directory has changed.
313  */
314 static void
315 updatepwd(char *dir)
316 {
317 	hashcd();				/* update command hash table */
318 
319 	if (prevdir)
320 		ckfree(prevdir);
321 	prevdir = curdir;
322 	curdir = dir ? savestr(dir) : NULL;
323 	setvar("PWD", curdir, VEXPORT);
324 	setvar("OLDPWD", prevdir, VEXPORT);
325 }
326 
327 int
328 pwdcmd(int argc, char **argv)
329 {
330 	char *p;
331 	int ch, phys;
332 
333 	optreset = 1; optind = 1; opterr = 0; /* initialize getopt */
334 	phys = Pflag;
335 	while ((ch = getopt(argc, argv, "LP")) != -1) {
336 		switch (ch) {
337 		case 'L':
338 			phys = 0;
339 			break;
340 		case 'P':
341 			phys = 1;
342 			break;
343 		default:
344 			error("unknown option: -%c", optopt);
345 			break;
346 		}
347 	}
348 	argc -= optind;
349 	argv += optind;
350 
351 	if (argc != 0)
352 		error("too many arguments");
353 
354 	if (!phys && getpwd()) {
355 		out1str(curdir);
356 		out1c('\n');
357 	} else {
358 		if ((p = getpwd2()) == NULL)
359 			error(".: %s", strerror(errno));
360 		out1str(p);
361 		out1c('\n');
362 	}
363 
364 	return 0;
365 }
366 
367 /*
368  * Get the current directory and cache the result in curdir.
369  */
370 static char *
371 getpwd(void)
372 {
373 	char *p;
374 
375 	if (curdir)
376 		return curdir;
377 
378 	p = getpwd2();
379 	if (p != NULL)
380 		curdir = savestr(p);
381 
382 	return curdir;
383 }
384 
385 #define MAXPWD 256
386 
387 /*
388  * Return the current directory.
389  */
390 static char *
391 getpwd2(void)
392 {
393 	char *pwd;
394 	int i;
395 
396 	for (i = MAXPWD;; i *= 2) {
397 		pwd = stalloc(i);
398 		if (getcwd(pwd, i) != NULL)
399 			return pwd;
400 		stunalloc(pwd);
401 		if (errno != ERANGE)
402 			break;
403 	}
404 
405 	return NULL;
406 }
407 
408 /*
409  * Initialize PWD in a new shell.
410  * If the shell is interactive, we need to warn if this fails.
411  */
412 void
413 pwd_init(int warn)
414 {
415 	char *pwd;
416 	struct stat stdot, stpwd;
417 
418 	pwd = lookupvar("PWD");
419 	if (pwd && *pwd == '/' && stat(".", &stdot) != -1 &&
420 	    stat(pwd, &stpwd) != -1 &&
421 	    stdot.st_dev == stpwd.st_dev &&
422 	    stdot.st_ino == stpwd.st_ino) {
423 		if (curdir)
424 			ckfree(curdir);
425 		curdir = savestr(pwd);
426 	}
427 	if (getpwd() == NULL && warn)
428 		out2fmt_flush("sh: cannot determine working directory\n");
429 	setvar("PWD", curdir, VEXPORT);
430 }
431