cd.c revision 262951 
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
35static char sccsid[] = "@(#)cd.c	8.2 (Berkeley) 5/4/95";
36#endif
37#endif /* not lint */
38#include <sys/cdefs.h>
39__FBSDID("$FreeBSD: stable/10/bin/sh/cd.c 262951 2014-03-09 17:04:31Z jmmv $");
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
68static int cdlogical(char *);
69static int cdphysical(char *);
70static int docd(char *, int, int);
71static char *getcomponent(void);
72static char *findcwd(char *);
73static void updatepwd(char *);
74static char *getpwd(void);
75static char *getpwd2(void);
76
77static char *curdir = NULL;	/* current working directory */
78static char *prevdir;		/* previous working directory */
79static char *cdcomppath;
80
81int
82cdcmd(int argc __unused, char **argv __unused)
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	phys = Pflag;
93	while ((ch = nextopt("eLP")) != '\0') {
94		switch (ch) {
95		case 'e':
96			getcwderr = 1;
97			break;
98		case 'L':
99			phys = 0;
100			break;
101		case 'P':
102			phys = 1;
103			break;
104		}
105	}
106
107	if (*argptr != NULL && argptr[1] != NULL)
108		error("too many arguments");
109
110	if ((dest = *argptr) == NULL && (dest = bltinlookup("HOME", 1)) == NULL)
111		error("HOME not set");
112	if (*dest == '\0')
113		dest = ".";
114	if (dest[0] == '-' && dest[1] == '\0') {
115		dest = prevdir ? prevdir : curdir;
116		if (dest)
117			print = 1;
118		else
119			dest = ".";
120	}
121	if (dest[0] == '/' ||
122	    (dest[0] == '.' && (dest[1] == '/' || dest[1] == '\0')) ||
123	    (dest[0] == '.' && dest[1] == '.' && (dest[2] == '/' || dest[2] == '\0')) ||
124	    (path = bltinlookup("CDPATH", 1)) == NULL)
125		path = nullstr;
126	while ((p = padvance(&path, dest)) != NULL) {
127		if (stat(p, &statb) < 0) {
128			if (errno != ENOENT)
129				errno1 = errno;
130		} else if (!S_ISDIR(statb.st_mode))
131			errno1 = ENOTDIR;
132		else {
133			if (!print) {
134				/*
135				 * XXX - rethink
136				 */
137				if (p[0] == '.' && p[1] == '/' && p[2] != '\0')
138					print = strcmp(p + 2, dest);
139				else
140					print = strcmp(p, dest);
141			}
142			rc = docd(p, print, phys);
143			if (rc >= 0)
144				return getcwderr ? rc : 0;
145			if (errno != ENOENT)
146				errno1 = errno;
147		}
148	}
149	error("%s: %s", dest, strerror(errno1));
150	/*NOTREACHED*/
151	return 0;
152}
153
154
155/*
156 * Actually change the directory.  In an interactive shell, print the
157 * directory name if "print" is nonzero.
158 */
159static int
160docd(char *dest, int print, int phys)
161{
162	int rc;
163
164	TRACE(("docd(\"%s\", %d, %d) called\n", dest, print, phys));
165
166	/* If logical cd fails, fall back to physical. */
167	if ((phys || (rc = cdlogical(dest)) < 0) && (rc = cdphysical(dest)) < 0)
168		return (-1);
169
170	if (print && iflag && curdir)
171		out1fmt("%s\n", curdir);
172
173	return (rc);
174}
175
176static int
177cdlogical(char *dest)
178{
179	char *p;
180	char *q;
181	char *component;
182	struct stat statb;
183	int first;
184	int badstat;
185	size_t len;
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	len = strlen(dest);
194	cdcomppath = stalloc(len + 1);
195	memcpy(cdcomppath, dest, len + 1);
196	STARTSTACKSTR(p);
197	if (*dest == '/') {
198		STPUTC('/', p);
199		cdcomppath++;
200	}
201	first = 1;
202	while ((q = getcomponent()) != NULL) {
203		if (q[0] == '\0' || (q[0] == '.' && q[1] == '\0'))
204			continue;
205		if (! first)
206			STPUTC('/', p);
207		first = 0;
208		component = q;
209		STPUTS(q, p);
210		if (equal(component, ".."))
211			continue;
212		STACKSTRNUL(p);
213		if (lstat(stackblock(), &statb) < 0) {
214			badstat = 1;
215			break;
216		}
217	}
218
219	INTOFF;
220	if ((p = findcwd(badstat ? NULL : dest)) == NULL || chdir(p) < 0) {
221		INTON;
222		return (-1);
223	}
224	updatepwd(p);
225	INTON;
226	return (0);
227}
228
229static int
230cdphysical(char *dest)
231{
232	char *p;
233	int rc = 0;
234
235	INTOFF;
236	if (chdir(dest) < 0) {
237		INTON;
238		return (-1);
239	}
240	p = findcwd(NULL);
241	if (p == NULL) {
242		warning("warning: failed to get name of current directory");
243		rc = 1;
244	}
245	updatepwd(p);
246	INTON;
247	return (rc);
248}
249
250/*
251 * Get the next component of the path name pointed to by cdcomppath.
252 * This routine overwrites the string pointed to by cdcomppath.
253 */
254static char *
255getcomponent(void)
256{
257	char *p;
258	char *start;
259
260	if ((p = cdcomppath) == NULL)
261		return NULL;
262	start = cdcomppath;
263	while (*p != '/' && *p != '\0')
264		p++;
265	if (*p == '\0') {
266		cdcomppath = NULL;
267	} else {
268		*p++ = '\0';
269		cdcomppath = p;
270	}
271	return start;
272}
273
274
275static char *
276findcwd(char *dir)
277{
278	char *new;
279	char *p;
280	size_t len;
281
282	/*
283	 * If our argument is NULL, we don't know the current directory
284	 * any more because we traversed a symbolic link or something
285	 * we couldn't stat().
286	 */
287	if (dir == NULL || curdir == NULL)
288		return getpwd2();
289	len = strlen(dir);
290	cdcomppath = stalloc(len + 1);
291	memcpy(cdcomppath, dir, len + 1);
292	STARTSTACKSTR(new);
293	if (*dir != '/') {
294		STPUTS(curdir, new);
295		if (STTOPC(new) == '/')
296			STUNPUTC(new);
297	}
298	while ((p = getcomponent()) != NULL) {
299		if (equal(p, "..")) {
300			while (new > stackblock() && (STUNPUTC(new), *new) != '/');
301		} else if (*p != '\0' && ! equal(p, ".")) {
302			STPUTC('/', new);
303			STPUTS(p, new);
304		}
305	}
306	if (new == stackblock())
307		STPUTC('/', new);
308	STACKSTRNUL(new);
309	return stackblock();
310}
311
312/*
313 * Update curdir (the name of the current directory) in response to a
314 * cd command.  We also call hashcd to let the routines in exec.c know
315 * that the current directory has changed.
316 */
317static void
318updatepwd(char *dir)
319{
320	hashcd();				/* update command hash table */
321
322	if (prevdir)
323		ckfree(prevdir);
324	prevdir = curdir;
325	curdir = dir ? savestr(dir) : NULL;
326	setvar("PWD", curdir, VEXPORT);
327	setvar("OLDPWD", prevdir, VEXPORT);
328}
329
330int
331pwdcmd(int argc __unused, char **argv __unused)
332{
333	char *p;
334	int ch, phys;
335
336	phys = Pflag;
337	while ((ch = nextopt("LP")) != '\0') {
338		switch (ch) {
339		case 'L':
340			phys = 0;
341			break;
342		case 'P':
343			phys = 1;
344			break;
345		}
346	}
347
348	if (*argptr != NULL)
349		error("too many arguments");
350
351	if (!phys && getpwd()) {
352		out1str(curdir);
353		out1c('\n');
354	} else {
355		if ((p = getpwd2()) == NULL)
356			error(".: %s", strerror(errno));
357		out1str(p);
358		out1c('\n');
359	}
360
361	return 0;
362}
363
364/*
365 * Get the current directory and cache the result in curdir.
366 */
367static char *
368getpwd(void)
369{
370	char *p;
371
372	if (curdir)
373		return curdir;
374
375	p = getpwd2();
376	if (p != NULL)
377		curdir = savestr(p);
378
379	return curdir;
380}
381
382#define MAXPWD 256
383
384/*
385 * Return the current directory.
386 */
387static char *
388getpwd2(void)
389{
390	char *pwd;
391	int i;
392
393	for (i = MAXPWD;; i *= 2) {
394		pwd = stalloc(i);
395		if (getcwd(pwd, i) != NULL)
396			return pwd;
397		stunalloc(pwd);
398		if (errno != ERANGE)
399			break;
400	}
401
402	return NULL;
403}
404
405/*
406 * Initialize PWD in a new shell.
407 * If the shell is interactive, we need to warn if this fails.
408 */
409void
410pwd_init(int warn)
411{
412	char *pwd;
413	struct stat stdot, stpwd;
414
415	pwd = lookupvar("PWD");
416	if (pwd && *pwd == '/' && stat(".", &stdot) != -1 &&
417	    stat(pwd, &stpwd) != -1 &&
418	    stdot.st_dev == stpwd.st_dev &&
419	    stdot.st_ino == stpwd.st_ino) {
420		if (curdir)
421			ckfree(curdir);
422		curdir = savestr(pwd);
423	}
424	if (getpwd() == NULL && warn)
425		out2fmt_flush("sh: cannot determine working directory\n");
426	setvar("PWD", curdir, VEXPORT);
427}
428