cd.c revision 100660 
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 * 3. All advertising materials mentioning features or use of this software
17 *    must display the following acknowledgement:
18 *	This product includes software developed by the University of
19 *	California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 *    may be used to endorse or promote products derived from this software
22 *    without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 */
36
37#ifndef lint
38#if 0
39static char sccsid[] = "@(#)cd.c	8.2 (Berkeley) 5/4/95";
40#endif
41#endif /* not lint */
42#include <sys/cdefs.h>
43__FBSDID("$FreeBSD: head/bin/sh/cd.c 100660 2002-07-25 09:46:31Z tjr $");
44
45#include <sys/types.h>
46#include <sys/stat.h>
47#include <stdlib.h>
48#include <string.h>
49#include <unistd.h>
50#include <errno.h>
51
52/*
53 * The cd and pwd commands.
54 */
55
56#include "shell.h"
57#include "var.h"
58#include "nodes.h"	/* for jobs.h */
59#include "jobs.h"
60#include "options.h"
61#include "output.h"
62#include "memalloc.h"
63#include "error.h"
64#include "exec.h"
65#include "redir.h"
66#include "mystring.h"
67#include "show.h"
68#include "cd.h"
69
70STATIC int cdlogical(char *);
71STATIC int cdphysical(char *);
72STATIC int docd(char *, int, int);
73STATIC char *getcomponent(void);
74STATIC int updatepwd(char *);
75
76char *curdir = NULL;		/* current working directory */
77char *prevdir;			/* previous working directory */
78STATIC char *cdcomppath;
79
80int
81cdcmd(int argc, char **argv)
82{
83	char *dest;
84	char *path;
85	char *p;
86	struct stat statb;
87	int ch, phys, print = 0;
88
89	optreset = 1; optind = 1; /* initialize getopt */
90	phys = 0;
91	while ((ch = getopt(argc, argv, "LP")) != -1) {
92		switch (ch) {
93		case 'L':
94			phys = 0;
95			break;
96		case 'P':
97			phys = 1;
98			break;
99		default:
100			error("unknown option: -%c", optopt);
101			break;
102		}
103	}
104	argc -= optind;
105	argv += optind;
106
107	if (argc > 1)
108		error("too many arguments");
109
110	if ((dest = *argv) == 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 == '/' || (path = bltinlookup("CDPATH", 1)) == NULL)
122		path = nullstr;
123	while ((p = padvance(&path, dest)) != NULL) {
124		if (stat(p, &statb) >= 0 && S_ISDIR(statb.st_mode)) {
125			if (!print) {
126				/*
127				 * XXX - rethink
128				 */
129				if (p[0] == '.' && p[1] == '/' && p[2] != '\0')
130					p += 2;
131				print = strcmp(p, dest);
132			}
133			if (docd(p, print, phys) >= 0)
134				return 0;
135		}
136	}
137	error("can't cd to %s", dest);
138	/*NOTREACHED*/
139	return 0;
140}
141
142
143/*
144 * Actually change the directory.  In an interactive shell, print the
145 * directory name if "print" is nonzero.
146 */
147STATIC int
148docd(char *dest, int print, int phys)
149{
150
151	TRACE(("docd(\"%s\", %d, %d) called\n", dest, print, phys));
152
153	/* If logical cd fails, fall back to physical. */
154	if ((phys || cdlogical(dest) < 0) && cdphysical(dest) < 0)
155		return (-1);
156
157	if (print && iflag && curdir)
158		out1fmt("%s\n", curdir);
159
160	return 0;
161}
162
163STATIC int
164cdlogical(char *dest)
165{
166	char *p;
167	char *q;
168	char *component;
169	struct stat statb;
170	int first;
171	int badstat;
172
173	/*
174	 *  Check each component of the path. If we find a symlink or
175	 *  something we can't stat, clear curdir to force a getcwd()
176	 *  next time we get the value of the current directory.
177	 */
178	badstat = 0;
179	cdcomppath = stalloc(strlen(dest) + 1);
180	scopy(dest, cdcomppath);
181	STARTSTACKSTR(p);
182	if (*dest == '/') {
183		STPUTC('/', p);
184		cdcomppath++;
185	}
186	first = 1;
187	while ((q = getcomponent()) != NULL) {
188		if (q[0] == '\0' || (q[0] == '.' && q[1] == '\0'))
189			continue;
190		if (! first)
191			STPUTC('/', p);
192		first = 0;
193		component = q;
194		while (*q)
195			STPUTC(*q++, p);
196		if (equal(component, ".."))
197			continue;
198		STACKSTRNUL(p);
199		if (lstat(stackblock(), &statb) < 0) {
200			badstat = 1;
201			break;
202		}
203	}
204
205	INTOFF;
206	if (updatepwd(badstat ? NULL : dest) < 0 || chdir(curdir) < 0) {
207		INTON;
208		return (-1);
209	}
210	INTON;
211	return (0);
212}
213
214STATIC int
215cdphysical(char *dest)
216{
217
218	INTOFF;
219	if (chdir(dest) < 0 || updatepwd(NULL) < 0) {
220		INTON;
221		return (-1);
222	}
223	INTON;
224	return (0);
225}
226
227/*
228 * Get the next component of the path name pointed to by cdcomppath.
229 * This routine overwrites the string pointed to by cdcomppath.
230 */
231STATIC char *
232getcomponent(void)
233{
234	char *p;
235	char *start;
236
237	if ((p = cdcomppath) == NULL)
238		return NULL;
239	start = cdcomppath;
240	while (*p != '/' && *p != '\0')
241		p++;
242	if (*p == '\0') {
243		cdcomppath = NULL;
244	} else {
245		*p++ = '\0';
246		cdcomppath = p;
247	}
248	return start;
249}
250
251
252/*
253 * Update curdir (the name of the current directory) in response to a
254 * cd command.  We also call hashcd to let the routines in exec.c know
255 * that the current directory has changed.
256 */
257STATIC int
258updatepwd(char *dir)
259{
260	char *new;
261	char *p;
262
263	hashcd();				/* update command hash table */
264
265	/*
266	 * If our argument is NULL, we don't know the current directory
267	 * any more because we traversed a symbolic link or something
268	 * we couldn't stat().
269	 */
270	if (dir == NULL || curdir == NULL)  {
271		if (prevdir)
272			ckfree(prevdir);
273		INTOFF;
274		prevdir = curdir;
275		curdir = NULL;
276		if (getpwd() == NULL) {
277			INTON;
278			return (-1);
279		}
280		setvar("PWD", curdir, VEXPORT);
281		setvar("OLDPWD", prevdir, VEXPORT);
282		INTON;
283		return (0);
284	}
285	cdcomppath = stalloc(strlen(dir) + 1);
286	scopy(dir, cdcomppath);
287	STARTSTACKSTR(new);
288	if (*dir != '/') {
289		p = curdir;
290		while (*p)
291			STPUTC(*p++, new);
292		if (p[-1] == '/')
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			while (*p)
301				STPUTC(*p++, new);
302		}
303	}
304	if (new == stackblock())
305		STPUTC('/', new);
306	STACKSTRNUL(new);
307	INTOFF;
308	if (prevdir)
309		ckfree(prevdir);
310	prevdir = curdir;
311	curdir = savestr(stackblock());
312	setvar("PWD", curdir, VEXPORT);
313	setvar("OLDPWD", prevdir, VEXPORT);
314	INTON;
315
316	return (0);
317}
318
319#define MAXPWD 256
320
321int
322pwdcmd(int argc, char **argv)
323{
324	char buf[MAXPWD];
325	int ch, phys;
326
327	optreset = 1; optind = 1; /* initialize getopt */
328	phys = 0;
329	while ((ch = getopt(argc, argv, "LP")) != -1) {
330		switch (ch) {
331		case 'L':
332			phys = 0;
333			break;
334		case 'P':
335			phys = 1;
336			break;
337		default:
338			error("unknown option: -%c", optopt);
339			break;
340		}
341	}
342	argc -= optind;
343	argv += optind;
344
345	if (argc != 0)
346		error("too many arguments");
347
348	if (!phys && getpwd()) {
349		out1str(curdir);
350		out1c('\n');
351	} else {
352		if (getcwd(buf, sizeof(buf)) == NULL)
353			error(".: %s", strerror(errno));
354		out1str(buf);
355		out1c('\n');
356	}
357
358	return 0;
359}
360
361/*
362 * Find out what the current directory is. If we already know the current
363 * directory, this routine returns immediately.
364 */
365char *
366getpwd(void)
367{
368	char buf[MAXPWD];
369
370	if (curdir)
371		return curdir;
372	if (getcwd(buf, sizeof(buf)) == NULL) {
373		char *pwd = getenv("PWD");
374		struct stat stdot, stpwd;
375
376		if (pwd && *pwd == '/' && stat(".", &stdot) != -1 &&
377		    stat(pwd, &stpwd) != -1 &&
378		    stdot.st_dev == stpwd.st_dev &&
379		    stdot.st_ino == stpwd.st_ino) {
380			curdir = savestr(pwd);
381			return curdir;
382		}
383		return NULL;
384	}
385	curdir = savestr(buf);
386
387	return curdir;
388}
389