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. 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("$FreeBSD$");
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(char **);
72static char *findcwd(char *);
73static void updatepwd(char *);
74static char *getpwd(void);
75static char *getpwd2(void);
76
77static char *curdir = NULL;	/* current working directory */
78
79int
80cdcmd(int argc __unused, char **argv __unused)
81{
82	const char *dest;
83	const char *path;
84	char *p;
85	struct stat statb;
86	int ch, phys, print = 0, getcwderr = 0;
87	int rc;
88	int errno1 = ENOENT;
89
90	phys = Pflag;
91	while ((ch = nextopt("eLP")) != '\0') {
92		switch (ch) {
93		case 'e':
94			getcwderr = 1;
95			break;
96		case 'L':
97			phys = 0;
98			break;
99		case 'P':
100			phys = 1;
101			break;
102		}
103	}
104
105	if (*argptr != NULL && argptr[1] != NULL)
106		error("too many arguments");
107
108	if ((dest = *argptr) == NULL && (dest = bltinlookup("HOME", 1)) == NULL)
109		error("HOME not set");
110	if (*dest == '\0')
111		dest = ".";
112	if (dest[0] == '-' && dest[1] == '\0') {
113		dest = bltinlookup("OLDPWD", 1);
114		if (dest == NULL)
115			error("OLDPWD not set");
116		print = 1;
117	}
118	if (dest[0] == '/' ||
119	    (dest[0] == '.' && (dest[1] == '/' || dest[1] == '\0')) ||
120	    (dest[0] == '.' && dest[1] == '.' && (dest[2] == '/' || dest[2] == '\0')) ||
121	    (path = bltinlookup("CDPATH", 1)) == NULL)
122		path = "";
123	while ((p = padvance(&path, NULL, dest)) != NULL) {
124		if (stat(p, &statb) < 0) {
125			if (errno != ENOENT)
126				errno1 = errno;
127		} else if (!S_ISDIR(statb.st_mode))
128			errno1 = ENOTDIR;
129		else {
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		 * Ignore write errors to preserve the invariant that the
171		 * current directory is changed iff the exit status is 0
172		 * (or 1 if -e was given and the full pathname could not be
173		 * determined).
174		 */
175		flushout(out1);
176		outclearerror(out1);
177	}
178
179	return (rc);
180}
181
182static int
183cdlogical(char *dest)
184{
185	char *p;
186	char *q;
187	char *component;
188	char *path;
189	struct stat statb;
190	int first;
191	int badstat;
192
193	/*
194	 *  Check each component of the path. If we find a symlink or
195	 *  something we can't stat, clear curdir to force a getcwd()
196	 *  next time we get the value of the current directory.
197	 */
198	badstat = 0;
199	path = stsavestr(dest);
200	STARTSTACKSTR(p);
201	if (*dest == '/') {
202		STPUTC('/', p);
203		path++;
204	}
205	first = 1;
206	while ((q = getcomponent(&path)) != NULL) {
207		if (q[0] == '\0' || (q[0] == '.' && q[1] == '\0'))
208			continue;
209		if (! first)
210			STPUTC('/', p);
211		first = 0;
212		component = q;
213		STPUTS(q, p);
214		if (equal(component, ".."))
215			continue;
216		STACKSTRNUL(p);
217		if (lstat(stackblock(), &statb) < 0) {
218			badstat = 1;
219			break;
220		}
221	}
222
223	INTOFF;
224	if ((p = findcwd(badstat ? NULL : dest)) == NULL || chdir(p) < 0) {
225		INTON;
226		return (-1);
227	}
228	updatepwd(p);
229	INTON;
230	return (0);
231}
232
233static int
234cdphysical(char *dest)
235{
236	char *p;
237	int rc = 0;
238
239	INTOFF;
240	if (chdir(dest) < 0) {
241		INTON;
242		return (-1);
243	}
244	p = findcwd(NULL);
245	if (p == NULL) {
246		warning("warning: failed to get name of current directory");
247		rc = 1;
248	}
249	updatepwd(p);
250	INTON;
251	return (rc);
252}
253
254/*
255 * Get the next component of the path name pointed to by *path.
256 * This routine overwrites *path and the string pointed to by it.
257 */
258static char *
259getcomponent(char **path)
260{
261	char *p;
262	char *start;
263
264	if ((p = *path) == NULL)
265		return NULL;
266	start = *path;
267	while (*p != '/' && *p != '\0')
268		p++;
269	if (*p == '\0') {
270		*path = NULL;
271	} else {
272		*p++ = '\0';
273		*path = p;
274	}
275	return start;
276}
277
278
279static char *
280findcwd(char *dir)
281{
282	char *new;
283	char *p;
284	char *path;
285
286	/*
287	 * If our argument is NULL, we don't know the current directory
288	 * any more because we traversed a symbolic link or something
289	 * we couldn't stat().
290	 */
291	if (dir == NULL || curdir == NULL)
292		return getpwd2();
293	path = stsavestr(dir);
294	STARTSTACKSTR(new);
295	if (*dir != '/') {
296		STPUTS(curdir, new);
297		if (STTOPC(new) == '/')
298			STUNPUTC(new);
299	}
300	while ((p = getcomponent(&path)) != NULL) {
301		if (equal(p, "..")) {
302			while (new > stackblock() && (STUNPUTC(new), *new) != '/');
303		} else if (*p != '\0' && ! equal(p, ".")) {
304			STPUTC('/', new);
305			STPUTS(p, new);
306		}
307	}
308	if (new == stackblock())
309		STPUTC('/', new);
310	STACKSTRNUL(new);
311	return stackblock();
312}
313
314/*
315 * Update curdir (the name of the current directory) in response to a
316 * cd command.  We also call hashcd to let the routines in exec.c know
317 * that the current directory has changed.
318 */
319static void
320updatepwd(char *dir)
321{
322	char *prevdir;
323
324	hashcd();				/* update command hash table */
325
326	setvar("PWD", dir, VEXPORT);
327	setvar("OLDPWD", curdir, VEXPORT);
328	prevdir = curdir;
329	curdir = dir ? savestr(dir) : NULL;
330	ckfree(prevdir);
331}
332
333int
334pwdcmd(int argc __unused, char **argv __unused)
335{
336	char *p;
337	int ch, phys;
338
339	phys = Pflag;
340	while ((ch = nextopt("LP")) != '\0') {
341		switch (ch) {
342		case 'L':
343			phys = 0;
344			break;
345		case 'P':
346			phys = 1;
347			break;
348		}
349	}
350
351	if (*argptr != NULL)
352		error("too many arguments");
353
354	if (!phys && getpwd()) {
355		out1str(curdir);
356		out1c('\n');
357	} else {
358		if ((p = getpwd2()) == NULL)
359			error(".: %s", strerror(errno));
360		out1str(p);
361		out1c('\n');
362	}
363
364	return 0;
365}
366
367/*
368 * Get the current directory and cache the result in curdir.
369 */
370static char *
371getpwd(void)
372{
373	char *p;
374
375	if (curdir)
376		return curdir;
377
378	p = getpwd2();
379	if (p != NULL) {
380		INTOFF;
381		curdir = savestr(p);
382		INTON;
383	}
384
385	return curdir;
386}
387
388#define MAXPWD 256
389
390/*
391 * Return the current directory.
392 */
393static char *
394getpwd2(void)
395{
396	char *pwd;
397	int i;
398
399	for (i = MAXPWD;; i *= 2) {
400		pwd = stalloc(i);
401		if (getcwd(pwd, i) != NULL)
402			return pwd;
403		stunalloc(pwd);
404		if (errno != ERANGE)
405			break;
406	}
407
408	return NULL;
409}
410
411/*
412 * Initialize PWD in a new shell.
413 * If the shell is interactive, we need to warn if this fails.
414 */
415void
416pwd_init(int warn)
417{
418	char *pwd;
419	struct stat stdot, stpwd;
420
421	pwd = lookupvar("PWD");
422	if (pwd && *pwd == '/' && stat(".", &stdot) != -1 &&
423	    stat(pwd, &stpwd) != -1 &&
424	    stdot.st_dev == stpwd.st_dev &&
425	    stdot.st_ino == stpwd.st_ino) {
426		if (curdir)
427			ckfree(curdir);
428		curdir = savestr(pwd);
429	}
430	if (getpwd() == NULL && warn)
431		out2fmt_flush("sh: cannot determine working directory\n");
432	setvar("PWD", curdir, VEXPORT);
433}
434