cd.c revision 222292 
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 222292 2011-05-25 21:38:16Z 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
67static int cdlogical(char *);
68static int cdphysical(char *);
69static int docd(char *, int, int);
70static char *getcomponent(void);
71static char *findcwd(char *);
72static void updatepwd(char *);
73static char *getpwd(void);
74static char *getpwd2(void);
75
76static char *curdir = NULL;	/* current working directory */
77static char *prevdir;		/* previous working directory */
78static char *cdcomppath;
79
80int
81cdcmd(int argc, char **argv)
82{
83	const char *dest;
84	const char *path;
85	char *p;
86	struct stat statb;
87	int ch, phys, print = 0, getcwderr = 0;
88	int rc;
89	int errno1 = ENOENT;
90
91	optreset = 1; optind = 1; opterr = 0; /* initialize getopt */
92	phys = Pflag;
93	while ((ch = getopt(argc, argv, "eLP")) != -1) {
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		default:
105			error("unknown option: -%c", optopt);
106			break;
107		}
108	}
109	argc -= optind;
110	argv += optind;
111
112	if (argc > 1)
113		error("too many arguments");
114
115	if ((dest = *argv) == NULL && (dest = bltinlookup("HOME", 1)) == NULL)
116		error("HOME not set");
117	if (*dest == '\0')
118		dest = ".";
119	if (dest[0] == '-' && dest[1] == '\0') {
120		dest = prevdir ? prevdir : curdir;
121		if (dest)
122			print = 1;
123		else
124			dest = ".";
125	}
126	if (*dest == '/' || (path = bltinlookup("CDPATH", 1)) == NULL)
127		path = nullstr;
128	while ((p = padvance(&path, dest)) != NULL) {
129		if (stat(p, &statb) >= 0 && S_ISDIR(statb.st_mode)) {
130			if (!print) {
131				/*
132				 * XXX - rethink
133				 */
134				if (p[0] == '.' && p[1] == '/' && p[2] != '\0')
135					print = strcmp(p + 2, dest);
136				else
137					print = strcmp(p, dest);
138			}
139			rc = docd(p, print, phys);
140			if (rc >= 0)
141				return getcwderr ? rc : 0;
142			if (errno != ENOENT)
143				errno1 = errno;
144		}
145	}
146	error("%s: %s", dest, strerror(errno1));
147	/*NOTREACHED*/
148	return 0;
149}
150
151
152/*
153 * Actually change the directory.  In an interactive shell, print the
154 * directory name if "print" is nonzero.
155 */
156static int
157docd(char *dest, int print, int phys)
158{
159	int rc;
160
161	TRACE(("docd(\"%s\", %d, %d) called\n", dest, print, phys));
162
163	/* If logical cd fails, fall back to physical. */
164	if ((phys || (rc = cdlogical(dest)) < 0) && (rc = cdphysical(dest)) < 0)
165		return (-1);
166
167	if (print && iflag && curdir)
168		out1fmt("%s\n", curdir);
169
170	return (rc);
171}
172
173static int
174cdlogical(char *dest)
175{
176	char *p;
177	char *q;
178	char *component;
179	struct stat statb;
180	int first;
181	int badstat;
182
183	/*
184	 *  Check each component of the path. If we find a symlink or
185	 *  something we can't stat, clear curdir to force a getcwd()
186	 *  next time we get the value of the current directory.
187	 */
188	badstat = 0;
189	cdcomppath = stalloc(strlen(dest) + 1);
190	scopy(dest, cdcomppath);
191	STARTSTACKSTR(p);
192	if (*dest == '/') {
193		STPUTC('/', p);
194		cdcomppath++;
195	}
196	first = 1;
197	while ((q = getcomponent()) != NULL) {
198		if (q[0] == '\0' || (q[0] == '.' && q[1] == '\0'))
199			continue;
200		if (! first)
201			STPUTC('/', p);
202		first = 0;
203		component = q;
204		STPUTS(q, p);
205		if (equal(component, ".."))
206			continue;
207		STACKSTRNUL(p);
208		if (lstat(stackblock(), &statb) < 0) {
209			badstat = 1;
210			break;
211		}
212	}
213
214	INTOFF;
215	if ((p = findcwd(badstat ? NULL : dest)) == NULL || chdir(p) < 0) {
216		INTON;
217		return (-1);
218	}
219	updatepwd(p);
220	INTON;
221	return (0);
222}
223
224static int
225cdphysical(char *dest)
226{
227	char *p;
228	int rc = 0;
229
230	INTOFF;
231	if (chdir(dest) < 0) {
232		INTON;
233		return (-1);
234	}
235	p = findcwd(NULL);
236	if (p == NULL) {
237		warning("warning: failed to get name of current directory");
238		rc = 1;
239	}
240	updatepwd(p);
241	INTON;
242	return (rc);
243}
244
245/*
246 * Get the next component of the path name pointed to by cdcomppath.
247 * This routine overwrites the string pointed to by cdcomppath.
248 */
249static char *
250getcomponent(void)
251{
252	char *p;
253	char *start;
254
255	if ((p = cdcomppath) == NULL)
256		return NULL;
257	start = cdcomppath;
258	while (*p != '/' && *p != '\0')
259		p++;
260	if (*p == '\0') {
261		cdcomppath = NULL;
262	} else {
263		*p++ = '\0';
264		cdcomppath = p;
265	}
266	return start;
267}
268
269
270static char *
271findcwd(char *dir)
272{
273	char *new;
274	char *p;
275
276	/*
277	 * If our argument is NULL, we don't know the current directory
278	 * any more because we traversed a symbolic link or something
279	 * we couldn't stat().
280	 */
281	if (dir == NULL || curdir == NULL)
282		return getpwd2();
283	cdcomppath = stalloc(strlen(dir) + 1);
284	scopy(dir, cdcomppath);
285	STARTSTACKSTR(new);
286	if (*dir != '/') {
287		STPUTS(curdir, new);
288		if (STTOPC(new) == '/')
289			STUNPUTC(new);
290	}
291	while ((p = getcomponent()) != NULL) {
292		if (equal(p, "..")) {
293			while (new > stackblock() && (STUNPUTC(new), *new) != '/');
294		} else if (*p != '\0' && ! equal(p, ".")) {
295			STPUTC('/', new);
296			STPUTS(p, new);
297		}
298	}
299	if (new == stackblock())
300		STPUTC('/', new);
301	STACKSTRNUL(new);
302	return stackblock();
303}
304
305/*
306 * Update curdir (the name of the current directory) in response to a
307 * cd command.  We also call hashcd to let the routines in exec.c know
308 * that the current directory has changed.
309 */
310static void
311updatepwd(char *dir)
312{
313	hashcd();				/* update command hash table */
314
315	if (prevdir)
316		ckfree(prevdir);
317	prevdir = curdir;
318	curdir = dir ? savestr(dir) : NULL;
319	setvar("PWD", curdir, VEXPORT);
320	setvar("OLDPWD", prevdir, VEXPORT);
321}
322
323int
324pwdcmd(int argc, char **argv)
325{
326	char *p;
327	int ch, phys;
328
329	optreset = 1; optind = 1; opterr = 0; /* initialize getopt */
330	phys = Pflag;
331	while ((ch = getopt(argc, argv, "LP")) != -1) {
332		switch (ch) {
333		case 'L':
334			phys = 0;
335			break;
336		case 'P':
337			phys = 1;
338			break;
339		default:
340			error("unknown option: -%c", optopt);
341			break;
342		}
343	}
344	argc -= optind;
345	argv += optind;
346
347	if (argc != 0)
348		error("too many arguments");
349
350	if (!phys && getpwd()) {
351		out1str(curdir);
352		out1c('\n');
353	} else {
354		if ((p = getpwd2()) == NULL)
355			error(".: %s", strerror(errno));
356		out1str(p);
357		out1c('\n');
358	}
359
360	return 0;
361}
362
363/*
364 * Get the current directory and cache the result in curdir.
365 */
366static char *
367getpwd(void)
368{
369	char *p;
370
371	if (curdir)
372		return curdir;
373
374	p = getpwd2();
375	if (p != NULL)
376		curdir = savestr(p);
377
378	return curdir;
379}
380
381#define MAXPWD 256
382
383/*
384 * Return the current directory.
385 */
386static char *
387getpwd2(void)
388{
389	char *pwd;
390	int i;
391
392	for (i = MAXPWD;; i *= 2) {
393		pwd = stalloc(i);
394		if (getcwd(pwd, i) != NULL)
395			return pwd;
396		stunalloc(pwd);
397		if (errno != ERANGE)
398			break;
399	}
400
401	return NULL;
402}
403
404/*
405 * Initialize PWD in a new shell.
406 * If the shell is interactive, we need to warn if this fails.
407 */
408void
409pwd_init(int warn)
410{
411	char *pwd;
412	struct stat stdot, stpwd;
413
414	pwd = lookupvar("PWD");
415	if (pwd && *pwd == '/' && stat(".", &stdot) != -1 &&
416	    stat(pwd, &stpwd) != -1 &&
417	    stdot.st_dev == stpwd.st_dev &&
418	    stdot.st_ino == stpwd.st_ino) {
419		if (curdir)
420			ckfree(curdir);
421		curdir = savestr(pwd);
422	}
423	if (getpwd() == NULL && warn)
424		out2fmt_flush("sh: cannot determine working directory\n");
425	setvar("PWD", curdir, VEXPORT);
426}
427