cd.c revision 127958 
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: head/bin/sh/cd.c 127958 2004-04-06 20:06:54Z markm $");
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
67STATIC int cdlogical(char *);
68STATIC int cdphysical(char *);
69STATIC int docd(char *, int, int);
70STATIC char *getcomponent(void);
71STATIC int updatepwd(char *);
72
73STATIC char *curdir = NULL;	/* current working directory */
74STATIC char *prevdir;		/* previous working directory */
75STATIC char *cdcomppath;
76
77int
78cdcmd(int argc, char **argv)
79{
80	char *dest;
81	char *path;
82	char *p;
83	struct stat statb;
84	int ch, phys, print = 0;
85
86	optreset = 1; optind = 1; opterr = 0; /* initialize getopt */
87	phys = Pflag;
88	while ((ch = getopt(argc, argv, "LP")) != -1) {
89		switch (ch) {
90		case 'L':
91			phys = 0;
92			break;
93		case 'P':
94			phys = 1;
95			break;
96		default:
97			error("unknown option: -%c", optopt);
98			break;
99		}
100	}
101	argc -= optind;
102	argv += optind;
103
104	if (argc > 1)
105		error("too many arguments");
106
107	if ((dest = *argv) == NULL && (dest = bltinlookup("HOME", 1)) == NULL)
108		error("HOME not set");
109	if (*dest == '\0')
110		dest = ".";
111	if (dest[0] == '-' && dest[1] == '\0') {
112		dest = prevdir ? prevdir : curdir;
113		if (dest)
114			print = 1;
115		else
116			dest = ".";
117	}
118	if (*dest == '/' || (path = bltinlookup("CDPATH", 1)) == NULL)
119		path = nullstr;
120	while ((p = padvance(&path, dest)) != NULL) {
121		if (stat(p, &statb) >= 0 && S_ISDIR(statb.st_mode)) {
122			if (!print) {
123				/*
124				 * XXX - rethink
125				 */
126				if (p[0] == '.' && p[1] == '/' && p[2] != '\0')
127					p += 2;
128				print = strcmp(p, dest);
129			}
130			if (docd(p, print, phys) >= 0)
131				return 0;
132		}
133	}
134	error("can't cd to %s", dest);
135	/*NOTREACHED*/
136	return 0;
137}
138
139
140/*
141 * Actually change the directory.  In an interactive shell, print the
142 * directory name if "print" is nonzero.
143 */
144STATIC int
145docd(char *dest, int print, int phys)
146{
147
148	TRACE(("docd(\"%s\", %d, %d) called\n", dest, print, phys));
149
150	/* If logical cd fails, fall back to physical. */
151	if ((phys || cdlogical(dest) < 0) && cdphysical(dest) < 0)
152		return (-1);
153
154	if (print && iflag && curdir)
155		out1fmt("%s\n", curdir);
156
157	return 0;
158}
159
160STATIC int
161cdlogical(char *dest)
162{
163	char *p;
164	char *q;
165	char *component;
166	struct stat statb;
167	int first;
168	int badstat;
169
170	/*
171	 *  Check each component of the path. If we find a symlink or
172	 *  something we can't stat, clear curdir to force a getcwd()
173	 *  next time we get the value of the current directory.
174	 */
175	badstat = 0;
176	cdcomppath = stalloc(strlen(dest) + 1);
177	scopy(dest, cdcomppath);
178	STARTSTACKSTR(p);
179	if (*dest == '/') {
180		STPUTC('/', p);
181		cdcomppath++;
182	}
183	first = 1;
184	while ((q = getcomponent()) != NULL) {
185		if (q[0] == '\0' || (q[0] == '.' && q[1] == '\0'))
186			continue;
187		if (! first)
188			STPUTC('/', p);
189		first = 0;
190		component = q;
191		while (*q)
192			STPUTC(*q++, p);
193		if (equal(component, ".."))
194			continue;
195		STACKSTRNUL(p);
196		if (lstat(stackblock(), &statb) < 0) {
197			badstat = 1;
198			break;
199		}
200	}
201
202	INTOFF;
203	if (updatepwd(badstat ? NULL : dest) < 0 || chdir(curdir) < 0) {
204		INTON;
205		return (-1);
206	}
207	INTON;
208	return (0);
209}
210
211STATIC int
212cdphysical(char *dest)
213{
214
215	INTOFF;
216	if (chdir(dest) < 0 || updatepwd(NULL) < 0) {
217		INTON;
218		return (-1);
219	}
220	INTON;
221	return (0);
222}
223
224/*
225 * Get the next component of the path name pointed to by cdcomppath.
226 * This routine overwrites the string pointed to by cdcomppath.
227 */
228STATIC char *
229getcomponent(void)
230{
231	char *p;
232	char *start;
233
234	if ((p = cdcomppath) == NULL)
235		return NULL;
236	start = cdcomppath;
237	while (*p != '/' && *p != '\0')
238		p++;
239	if (*p == '\0') {
240		cdcomppath = NULL;
241	} else {
242		*p++ = '\0';
243		cdcomppath = p;
244	}
245	return start;
246}
247
248
249/*
250 * Update curdir (the name of the current directory) in response to a
251 * cd command.  We also call hashcd to let the routines in exec.c know
252 * that the current directory has changed.
253 */
254STATIC int
255updatepwd(char *dir)
256{
257	char *new;
258	char *p;
259
260	hashcd();				/* update command hash table */
261
262	/*
263	 * If our argument is NULL, we don't know the current directory
264	 * any more because we traversed a symbolic link or something
265	 * we couldn't stat().
266	 */
267	if (dir == NULL || curdir == NULL)  {
268		if (prevdir)
269			ckfree(prevdir);
270		INTOFF;
271		prevdir = curdir;
272		curdir = NULL;
273		if (getpwd() == NULL) {
274			INTON;
275			return (-1);
276		}
277		setvar("PWD", curdir, VEXPORT);
278		setvar("OLDPWD", prevdir, VEXPORT);
279		INTON;
280		return (0);
281	}
282	cdcomppath = stalloc(strlen(dir) + 1);
283	scopy(dir, cdcomppath);
284	STARTSTACKSTR(new);
285	if (*dir != '/') {
286		p = curdir;
287		while (*p)
288			STPUTC(*p++, new);
289		if (p[-1] == '/')
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			while (*p)
298				STPUTC(*p++, new);
299		}
300	}
301	if (new == stackblock())
302		STPUTC('/', new);
303	STACKSTRNUL(new);
304	INTOFF;
305	if (prevdir)
306		ckfree(prevdir);
307	prevdir = curdir;
308	curdir = savestr(stackblock());
309	setvar("PWD", curdir, VEXPORT);
310	setvar("OLDPWD", prevdir, VEXPORT);
311	INTON;
312
313	return (0);
314}
315
316int
317pwdcmd(int argc, char **argv)
318{
319	char buf[PATH_MAX];
320	int ch, phys;
321
322	optreset = 1; optind = 1; opterr = 0; /* initialize getopt */
323	phys = Pflag;
324	while ((ch = getopt(argc, argv, "LP")) != -1) {
325		switch (ch) {
326		case 'L':
327			phys = 0;
328			break;
329		case 'P':
330			phys = 1;
331			break;
332		default:
333			error("unknown option: -%c", optopt);
334			break;
335		}
336	}
337	argc -= optind;
338	argv += optind;
339
340	if (argc != 0)
341		error("too many arguments");
342
343	if (!phys && getpwd()) {
344		out1str(curdir);
345		out1c('\n');
346	} else {
347		if (getcwd(buf, sizeof(buf)) == NULL)
348			error(".: %s", strerror(errno));
349		out1str(buf);
350		out1c('\n');
351	}
352
353	return 0;
354}
355
356/*
357 * Find out what the current directory is. If we already know the current
358 * directory, this routine returns immediately.
359 */
360char *
361getpwd(void)
362{
363	char buf[PATH_MAX];
364
365	if (curdir)
366		return curdir;
367	if (getcwd(buf, sizeof(buf)) == NULL) {
368		char *pwd = getenv("PWD");
369		struct stat stdot, stpwd;
370
371		if (pwd && *pwd == '/' && stat(".", &stdot) != -1 &&
372		    stat(pwd, &stpwd) != -1 &&
373		    stdot.st_dev == stpwd.st_dev &&
374		    stdot.st_ino == stpwd.st_ino) {
375			curdir = savestr(pwd);
376			return curdir;
377		}
378		return NULL;
379	}
380	curdir = savestr(buf);
381
382	return curdir;
383}
384