cd.c revision 297749 
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 297749 2016-04-09 14:09:14Z jilles $");
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
186	/*
187	 *  Check each component of the path. If we find a symlink or
188	 *  something we can't stat, clear curdir to force a getcwd()
189	 *  next time we get the value of the current directory.
190	 */
191	badstat = 0;
192	cdcomppath = stsavestr(dest);
193	STARTSTACKSTR(p);
194	if (*dest == '/') {
195		STPUTC('/', p);
196		cdcomppath++;
197	}
198	first = 1;
199	while ((q = getcomponent()) != NULL) {
200		if (q[0] == '\0' || (q[0] == '.' && q[1] == '\0'))
201			continue;
202		if (! first)
203			STPUTC('/', p);
204		first = 0;
205		component = q;
206		STPUTS(q, p);
207		if (equal(component, ".."))
208			continue;
209		STACKSTRNUL(p);
210		if (lstat(stackblock(), &statb) < 0) {
211			badstat = 1;
212			break;
213		}
214	}
215
216	INTOFF;
217	if ((p = findcwd(badstat ? NULL : dest)) == NULL || chdir(p) < 0) {
218		INTON;
219		return (-1);
220	}
221	updatepwd(p);
222	INTON;
223	return (0);
224}
225
226static int
227cdphysical(char *dest)
228{
229	char *p;
230	int rc = 0;
231
232	INTOFF;
233	if (chdir(dest) < 0) {
234		INTON;
235		return (-1);
236	}
237	p = findcwd(NULL);
238	if (p == NULL) {
239		warning("warning: failed to get name of current directory");
240		rc = 1;
241	}
242	updatepwd(p);
243	INTON;
244	return (rc);
245}
246
247/*
248 * Get the next component of the path name pointed to by cdcomppath.
249 * This routine overwrites the string pointed to by cdcomppath.
250 */
251static char *
252getcomponent(void)
253{
254	char *p;
255	char *start;
256
257	if ((p = cdcomppath) == NULL)
258		return NULL;
259	start = cdcomppath;
260	while (*p != '/' && *p != '\0')
261		p++;
262	if (*p == '\0') {
263		cdcomppath = NULL;
264	} else {
265		*p++ = '\0';
266		cdcomppath = p;
267	}
268	return start;
269}
270
271
272static char *
273findcwd(char *dir)
274{
275	char *new;
276	char *p;
277
278	/*
279	 * If our argument is NULL, we don't know the current directory
280	 * any more because we traversed a symbolic link or something
281	 * we couldn't stat().
282	 */
283	if (dir == NULL || curdir == NULL)
284		return getpwd2();
285	cdcomppath = stsavestr(dir);
286	STARTSTACKSTR(new);
287	if (*dir != '/') {
288		STPUTS(curdir, new);
289		if (STTOPC(new) == '/')
290			STUNPUTC(new);
291	}
292	while ((p = getcomponent()) != NULL) {
293		if (equal(p, "..")) {
294			while (new > stackblock() && (STUNPUTC(new), *new) != '/');
295		} else if (*p != '\0' && ! equal(p, ".")) {
296			STPUTC('/', new);
297			STPUTS(p, new);
298		}
299	}
300	if (new == stackblock())
301		STPUTC('/', new);
302	STACKSTRNUL(new);
303	return stackblock();
304}
305
306/*
307 * Update curdir (the name of the current directory) in response to a
308 * cd command.  We also call hashcd to let the routines in exec.c know
309 * that the current directory has changed.
310 */
311static void
312updatepwd(char *dir)
313{
314	hashcd();				/* update command hash table */
315
316	if (prevdir)
317		ckfree(prevdir);
318	prevdir = curdir;
319	curdir = dir ? savestr(dir) : NULL;
320	setvar("PWD", curdir, VEXPORT);
321	setvar("OLDPWD", prevdir, VEXPORT);
322}
323
324int
325pwdcmd(int argc __unused, char **argv __unused)
326{
327	char *p;
328	int ch, phys;
329
330	phys = Pflag;
331	while ((ch = nextopt("LP")) != '\0') {
332		switch (ch) {
333		case 'L':
334			phys = 0;
335			break;
336		case 'P':
337			phys = 1;
338			break;
339		}
340	}
341
342	if (*argptr != NULL)
343		error("too many arguments");
344
345	if (!phys && getpwd()) {
346		out1str(curdir);
347		out1c('\n');
348	} else {
349		if ((p = getpwd2()) == NULL)
350			error(".: %s", strerror(errno));
351		out1str(p);
352		out1c('\n');
353	}
354
355	return 0;
356}
357
358/*
359 * Get the current directory and cache the result in curdir.
360 */
361static char *
362getpwd(void)
363{
364	char *p;
365
366	if (curdir)
367		return curdir;
368
369	p = getpwd2();
370	if (p != NULL)
371		curdir = savestr(p);
372
373	return curdir;
374}
375
376#define MAXPWD 256
377
378/*
379 * Return the current directory.
380 */
381static char *
382getpwd2(void)
383{
384	char *pwd;
385	int i;
386
387	for (i = MAXPWD;; i *= 2) {
388		pwd = stalloc(i);
389		if (getcwd(pwd, i) != NULL)
390			return pwd;
391		stunalloc(pwd);
392		if (errno != ERANGE)
393			break;
394	}
395
396	return NULL;
397}
398
399/*
400 * Initialize PWD in a new shell.
401 * If the shell is interactive, we need to warn if this fails.
402 */
403void
404pwd_init(int warn)
405{
406	char *pwd;
407	struct stat stdot, stpwd;
408
409	pwd = lookupvar("PWD");
410	if (pwd && *pwd == '/' && stat(".", &stdot) != -1 &&
411	    stat(pwd, &stpwd) != -1 &&
412	    stdot.st_dev == stpwd.st_dev &&
413	    stdot.st_ino == stpwd.st_ino) {
414		if (curdir)
415			ckfree(curdir);
416		curdir = savestr(pwd);
417	}
418	if (getpwd() == NULL && warn)
419		out2fmt_flush("sh: cannot determine working directory\n");
420	setvar("PWD", curdir, VEXPORT);
421}
422