cd.c revision 159551 
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 159551 2006-06-12 21:06:00Z stefanf $");
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					print = strcmp(p + 2, dest);
128				else
129					print = strcmp(p, dest);
130			}
131			if (docd(p, print, phys) >= 0)
132				return 0;
133		}
134	}
135	error("can't cd to %s", dest);
136	/*NOTREACHED*/
137	return 0;
138}
139
140
141/*
142 * Actually change the directory.  In an interactive shell, print the
143 * directory name if "print" is nonzero.
144 */
145STATIC int
146docd(char *dest, int print, int phys)
147{
148
149	TRACE(("docd(\"%s\", %d, %d) called\n", dest, print, phys));
150
151	/* If logical cd fails, fall back to physical. */
152	if ((phys || cdlogical(dest) < 0) && cdphysical(dest) < 0)
153		return (-1);
154
155	if (print && iflag && curdir)
156		out1fmt("%s\n", curdir);
157
158	return 0;
159}
160
161STATIC int
162cdlogical(char *dest)
163{
164	char *p;
165	char *q;
166	char *component;
167	struct stat statb;
168	int first;
169	int badstat;
170
171	/*
172	 *  Check each component of the path. If we find a symlink or
173	 *  something we can't stat, clear curdir to force a getcwd()
174	 *  next time we get the value of the current directory.
175	 */
176	badstat = 0;
177	cdcomppath = stalloc(strlen(dest) + 1);
178	scopy(dest, cdcomppath);
179	STARTSTACKSTR(p);
180	if (*dest == '/') {
181		STPUTC('/', p);
182		cdcomppath++;
183	}
184	first = 1;
185	while ((q = getcomponent()) != NULL) {
186		if (q[0] == '\0' || (q[0] == '.' && q[1] == '\0'))
187			continue;
188		if (! first)
189			STPUTC('/', p);
190		first = 0;
191		component = q;
192		while (*q)
193			STPUTC(*q++, p);
194		if (equal(component, ".."))
195			continue;
196		STACKSTRNUL(p);
197		if (lstat(stackblock(), &statb) < 0) {
198			badstat = 1;
199			break;
200		}
201	}
202
203	INTOFF;
204	if (updatepwd(badstat ? NULL : dest) < 0 || chdir(curdir) < 0) {
205		INTON;
206		return (-1);
207	}
208	INTON;
209	return (0);
210}
211
212STATIC int
213cdphysical(char *dest)
214{
215
216	INTOFF;
217	if (chdir(dest) < 0 || updatepwd(NULL) < 0) {
218		INTON;
219		return (-1);
220	}
221	INTON;
222	return (0);
223}
224
225/*
226 * Get the next component of the path name pointed to by cdcomppath.
227 * This routine overwrites the string pointed to by cdcomppath.
228 */
229STATIC char *
230getcomponent(void)
231{
232	char *p;
233	char *start;
234
235	if ((p = cdcomppath) == NULL)
236		return NULL;
237	start = cdcomppath;
238	while (*p != '/' && *p != '\0')
239		p++;
240	if (*p == '\0') {
241		cdcomppath = NULL;
242	} else {
243		*p++ = '\0';
244		cdcomppath = p;
245	}
246	return start;
247}
248
249
250/*
251 * Update curdir (the name of the current directory) in response to a
252 * cd command.  We also call hashcd to let the routines in exec.c know
253 * that the current directory has changed.
254 */
255STATIC int
256updatepwd(char *dir)
257{
258	char *new;
259	char *p;
260
261	hashcd();				/* update command hash table */
262
263	/*
264	 * If our argument is NULL, we don't know the current directory
265	 * any more because we traversed a symbolic link or something
266	 * we couldn't stat().
267	 */
268	if (dir == NULL || curdir == NULL)  {
269		if (prevdir)
270			ckfree(prevdir);
271		INTOFF;
272		prevdir = curdir;
273		curdir = NULL;
274		if (getpwd() == NULL) {
275			INTON;
276			return (-1);
277		}
278		setvar("PWD", curdir, VEXPORT);
279		setvar("OLDPWD", prevdir, VEXPORT);
280		INTON;
281		return (0);
282	}
283	cdcomppath = stalloc(strlen(dir) + 1);
284	scopy(dir, cdcomppath);
285	STARTSTACKSTR(new);
286	if (*dir != '/') {
287		p = curdir;
288		while (*p)
289			STPUTC(*p++, new);
290		if (p[-1] == '/')
291			STUNPUTC(new);
292	}
293	while ((p = getcomponent()) != NULL) {
294		if (equal(p, "..")) {
295			while (new > stackblock() && (STUNPUTC(new), *new) != '/');
296		} else if (*p != '\0' && ! equal(p, ".")) {
297			STPUTC('/', new);
298			while (*p)
299				STPUTC(*p++, new);
300		}
301	}
302	if (new == stackblock())
303		STPUTC('/', new);
304	STACKSTRNUL(new);
305	INTOFF;
306	if (prevdir)
307		ckfree(prevdir);
308	prevdir = curdir;
309	curdir = savestr(stackblock());
310	setvar("PWD", curdir, VEXPORT);
311	setvar("OLDPWD", prevdir, VEXPORT);
312	INTON;
313
314	return (0);
315}
316
317int
318pwdcmd(int argc, char **argv)
319{
320	char buf[PATH_MAX];
321	int ch, phys;
322
323	optreset = 1; optind = 1; opterr = 0; /* initialize getopt */
324	phys = Pflag;
325	while ((ch = getopt(argc, argv, "LP")) != -1) {
326		switch (ch) {
327		case 'L':
328			phys = 0;
329			break;
330		case 'P':
331			phys = 1;
332			break;
333		default:
334			error("unknown option: -%c", optopt);
335			break;
336		}
337	}
338	argc -= optind;
339	argv += optind;
340
341	if (argc != 0)
342		error("too many arguments");
343
344	if (!phys && getpwd()) {
345		out1str(curdir);
346		out1c('\n');
347	} else {
348		if (getcwd(buf, sizeof(buf)) == NULL)
349			error(".: %s", strerror(errno));
350		out1str(buf);
351		out1c('\n');
352	}
353
354	return 0;
355}
356
357/*
358 * Find out what the current directory is. If we already know the current
359 * directory, this routine returns immediately.
360 */
361char *
362getpwd(void)
363{
364	char buf[PATH_MAX];
365
366	if (curdir)
367		return curdir;
368	if (getcwd(buf, sizeof(buf)) == NULL) {
369		char *pwd = getenv("PWD");
370		struct stat stdot, stpwd;
371
372		if (pwd && *pwd == '/' && stat(".", &stdot) != -1 &&
373		    stat(pwd, &stpwd) != -1 &&
374		    stdot.st_dev == stpwd.st_dev &&
375		    stdot.st_ino == stpwd.st_ino) {
376			curdir = savestr(pwd);
377			return curdir;
378		}
379		return NULL;
380	}
381	curdir = savestr(buf);
382
383	return curdir;
384}
385