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source: kBuild/trunk/src/ash/cd.c@ 1158

Last change on this file since 1158 was 843, checked in by bird, 18 years ago

HAVE_SYS_CDEFS_H

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1/* $NetBSD: cd.c,v 1.34 2003/11/14 20:00:28 dsl Exp $ */
2
3/*-
4 * Copyright (c) 1991, 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * This code is derived from software contributed to Berkeley by
8 * Kenneth Almquist.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. Neither the name of the University nor the names of its contributors
19 * may be used to endorse or promote products derived from this software
20 * without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 */
34
35#ifdef HAVE_SYS_CDEFS_H
36#include <sys/cdefs.h>
37#endif
38#ifndef lint
39#if 0
40static char sccsid[] = "@(#)cd.c 8.2 (Berkeley) 5/4/95";
41#else
42__RCSID("$NetBSD: cd.c,v 1.34 2003/11/14 20:00:28 dsl Exp $");
43#endif
44#endif /* not lint */
45
46#include <sys/types.h>
47#include <sys/stat.h>
48#include <stdlib.h>
49#include <string.h>
50#include <unistd.h>
51#include <errno.h>
52
53/*
54 * The cd and pwd commands.
55 */
56
57#include "shell.h"
58#include "var.h"
59#include "nodes.h" /* for jobs.h */
60#include "jobs.h"
61#include "options.h"
62#include "output.h"
63#include "memalloc.h"
64#include "error.h"
65#include "exec.h"
66#include "redir.h"
67#include "mystring.h"
68#include "show.h"
69#include "cd.h"
70
71STATIC int docd(char *, int);
72STATIC char *getcomponent(void);
73STATIC void updatepwd(char *);
74STATIC void find_curdir(int noerror);
75
76char *curdir = NULL; /* current working directory */
77char *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, *d;
86 struct stat statb;
87 int print = cdprint; /* set -cdprint to enable */
88
89 nextopt(nullstr);
90
91 /*
92 * Try (quite hard) to have 'curdir' defined, nothing has set
93 * it on entry to the shell, but we want 'cd fred; cd -' to work.
94 */
95 getpwd(1);
96 dest = *argptr;
97 if (dest == NULL) {
98 dest = bltinlookup("HOME", 1);
99 if (dest == NULL)
100 error("HOME not set");
101 } else {
102 if (argptr[1]) {
103 /* Do 'ksh' style substitution */
104 if (!curdir)
105 error("PWD not set");
106 p = strstr(curdir, dest);
107 if (!p)
108 error("bad substitution");
109 d = stalloc(strlen(curdir) + strlen(argptr[1]) + 1);
110 memcpy(d, curdir, p - curdir);
111 strcpy(d + (p - curdir), argptr[1]);
112 strcat(d, p + strlen(dest));
113 dest = d;
114 print = 1;
115 }
116 }
117
118 if (dest[0] == '-' && dest[1] == '\0') {
119 dest = prevdir ? prevdir : curdir;
120 print = 1;
121 }
122 if (*dest == '\0')
123 dest = ".";
124 if (IS_ROOT(dest) || (path = bltinlookup("CDPATH", 1)) == NULL)
125 path = nullstr;
126 while ((p = padvance(&path, dest)) != NULL) {
127 if (stat(p, &statb) >= 0 && S_ISDIR(statb.st_mode)) {
128 if (!print) {
129 /*
130 * XXX - rethink
131 */
132 if (p[0] == '.' && p[1] == '/' && p[2] != '\0')
133 p += 2;
134 print = strcmp(p, dest);
135 }
136 if (docd(p, print) >= 0)
137 return 0;
138
139 }
140 }
141 error("can't cd to %s", dest);
142 /* NOTREACHED */
143}
144
145
146/*
147 * Actually do the chdir. In an interactive shell, print the
148 * directory name if "print" is nonzero.
149 */
150
151STATIC int
152docd(char *dest, int print)
153{
154 char *p;
155 char *q;
156 char *component;
157 struct stat statb;
158 int first;
159 int badstat;
160
161 TRACE(("docd(\"%s\", %d) called\n", dest, print));
162
163 /*
164 * Check each component of the path. If we find a symlink or
165 * something we can't stat, clear curdir to force a getcwd()
166 * next time we get the value of the current directory.
167 */
168 badstat = 0;
169 cdcomppath = stalloc(strlen(dest) + 1);
170 scopy(dest, cdcomppath);
171 STARTSTACKSTR(p);
172 if (IS_ROOT(dest)) {
173 STPUTC('/', p);
174 cdcomppath++;
175 }
176 first = 1;
177 while ((q = getcomponent()) != NULL) {
178 if (q[0] == '\0' || (q[0] == '.' && q[1] == '\0'))
179 continue;
180 if (! first)
181 STPUTC('/', p);
182 first = 0;
183 component = q;
184 while (*q)
185 STPUTC(*q++, p);
186 if (equal(component, ".."))
187 continue;
188 STACKSTRNUL(p);
189 if ((lstat(stackblock(), &statb) < 0)
190 || (S_ISLNK(statb.st_mode))) {
191 /* print = 1; */
192 badstat = 1;
193 break;
194 }
195 }
196
197 INTOFF;
198 if (chdir(dest) < 0) {
199 INTON;
200 return -1;
201 }
202 updatepwd(badstat ? NULL : dest);
203 INTON;
204 if (print && iflag && curdir)
205 out1fmt("%s\n", curdir);
206 return 0;
207}
208
209
210/*
211 * Get the next component of the path name pointed to by cdcomppath.
212 * This routine overwrites the string pointed to by cdcomppath.
213 */
214
215STATIC char *
216getcomponent()
217{
218 char *p;
219 char *start;
220
221 if ((p = cdcomppath) == NULL)
222 return NULL;
223 start = cdcomppath;
224 while (*p != '/' && *p != '\0')
225 p++;
226 if (*p == '\0') {
227 cdcomppath = NULL;
228 } else {
229 *p++ = '\0';
230 cdcomppath = p;
231 }
232 return start;
233}
234
235
236
237/*
238 * Update curdir (the name of the current directory) in response to a
239 * cd command. We also call hashcd to let the routines in exec.c know
240 * that the current directory has changed.
241 */
242
243STATIC void
244updatepwd(char *dir)
245{
246 char *new;
247 char *p;
248
249 hashcd(); /* update command hash table */
250
251 /*
252 * If our argument is NULL, we don't know the current directory
253 * any more because we traversed a symbolic link or something
254 * we couldn't stat().
255 */
256 if (dir == NULL || curdir == NULL) {
257 if (prevdir)
258 ckfree(prevdir);
259 INTOFF;
260 prevdir = curdir;
261 curdir = NULL;
262 getpwd(1);
263 INTON;
264 if (curdir)
265 setvar("PWD", curdir, VEXPORT);
266 else
267 unsetvar("PWD", 0);
268 return;
269 }
270 cdcomppath = stalloc(strlen(dir) + 1);
271 scopy(dir, cdcomppath);
272 STARTSTACKSTR(new);
273 if (!IS_ROOT(dir)) {
274 p = curdir;
275 while (*p)
276 STPUTC(*p++, new);
277 if (p[-1] == '/')
278 STUNPUTC(new);
279 }
280 while ((p = getcomponent()) != NULL) {
281 if (equal(p, "..")) {
282 while (new > stackblock() && (STUNPUTC(new), *new) != '/');
283 } else if (*p != '\0' && ! equal(p, ".")) {
284 STPUTC('/', new);
285 while (*p)
286 STPUTC(*p++, new);
287 }
288 }
289 if (new == stackblock())
290 STPUTC('/', new);
291 STACKSTRNUL(new);
292 INTOFF;
293 if (prevdir)
294 ckfree(prevdir);
295 prevdir = curdir;
296 curdir = savestr(stackblock());
297 setvar("PWD", curdir, VEXPORT);
298 INTON;
299}
300
301/*
302 * Posix says the default should be 'pwd -L' (as below), however
303 * the 'cd' command (above) does something much nearer to the
304 * posix 'cd -P' (not the posix default of 'cd -L').
305 * If 'cd' is changed to support -P/L then the default here
306 * needs to be revisited if the historic behaviour is to be kept.
307 */
308
309int
310pwdcmd(int argc, char **argv)
311{
312 int i;
313 char opt = 'L';
314
315 while ((i = nextopt("LP")) != '\0')
316 opt = i;
317 if (*argptr)
318 error("unexpected argument");
319
320 if (opt == 'L')
321 getpwd(0);
322 else
323 find_curdir(0);
324
325 setvar("PWD", curdir, VEXPORT);
326 out1str(curdir);
327 out1c('\n');
328 return 0;
329}
330
331
332
333
334#define MAXPWD 256
335
336/*
337 * Find out what the current directory is. If we already know the current
338 * directory, this routine returns immediately.
339 */
340void
341getpwd(int noerror)
342{
343 char *pwd;
344 struct stat stdot, stpwd;
345 static int first = 1;
346
347 if (curdir)
348 return;
349
350 if (first) {
351 first = 0;
352 pwd = getenv("PWD");
353 if (pwd && IS_ROOT(pwd) && stat(".", &stdot) != -1 &&
354 stat(pwd, &stpwd) != -1 &&
355 stdot.st_dev == stpwd.st_dev &&
356 stdot.st_ino == stpwd.st_ino) {
357 curdir = savestr(pwd);
358 return;
359 }
360 }
361
362 find_curdir(noerror);
363
364 return;
365}
366
367STATIC void
368find_curdir(int noerror)
369{
370 int i;
371 char *pwd;
372
373 /*
374 * Things are a bit complicated here; we could have just used
375 * getcwd, but traditionally getcwd is implemented using popen
376 * to /bin/pwd. This creates a problem for us, since we cannot
377 * keep track of the job if it is being ran behind our backs.
378 * So we re-implement getcwd(), and we suppress interrupts
379 * throughout the process. This is not completely safe, since
380 * the user can still break out of it by killing the pwd program.
381 * We still try to use getcwd for systems that we know have a
382 * c implementation of getcwd, that does not open a pipe to
383 * /bin/pwd.
384 */
385#if defined(__NetBSD__) || defined(__SVR4) || defined(__INNOTEK_LIBC__)
386
387 for (i = MAXPWD;; i *= 2) {
388 pwd = stalloc(i);
389 if (getcwd(pwd, i) != NULL) {
390 curdir = savestr(pwd);
391 return;
392 }
393 stunalloc(pwd);
394 if (errno == ERANGE)
395 continue;
396 if (!noerror)
397 error("getcwd() failed: %s", strerror(errno));
398 return;
399 }
400#else
401 {
402 char *p;
403 int status;
404 struct job *jp;
405 int pip[2];
406
407 pwd = stalloc(MAXPWD);
408 INTOFF;
409 if (pipe(pip) < 0)
410 error("Pipe call failed");
411 jp = makejob((union node *)NULL, 1);
412 if (forkshell(jp, (union node *)NULL, FORK_NOJOB) == 0) {
413 (void) close(pip[0]);
414 if (pip[1] != 1) {
415 close(1);
416 copyfd(pip[1], 1);
417 close(pip[1]);
418 }
419 (void) execl("/bin/pwd", "pwd", (char *)0);
420 error("Cannot exec /bin/pwd");
421 }
422 (void) close(pip[1]);
423 pip[1] = -1;
424 p = pwd;
425 while ((i = read(pip[0], p, pwd + MAXPWD - p)) > 0
426 || (i == -1 && errno == EINTR)) {
427 if (i > 0)
428 p += i;
429 }
430 (void) close(pip[0]);
431 pip[0] = -1;
432 status = waitforjob(jp);
433 if (status != 0)
434 error((char *)0);
435 if (i < 0 || p == pwd || p[-1] != '\n') {
436 if (noerror) {
437 INTON;
438 return;
439 }
440 error("pwd command failed");
441 }
442 p[-1] = '\0';
443 INTON;
444 curdir = savestr(pwd);
445 return;
446 }
447#endif
448}
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