Annotation of src/lib/libc/gen/getcwd.c, Revision 1.31
1.31 ! itojun 1: /* $NetBSD: getcwd.c,v 1.30 2003/08/03 04:14:00 itojun Exp $ */
1.4 cgd 2:
1.1 cgd 3: /*
1.8 perry 4: * Copyright (c) 1989, 1991, 1993, 1995
1.4 cgd 5: * The Regents of the University of California. All rights reserved.
1.1 cgd 6: *
1.8 perry 7: * This code is derived from software contributed to Berkeley by
8: * Jan-Simon Pendry.
9: *
1.1 cgd 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. All advertising materials mentioning features or use of this software
19: * must display the following acknowledgement:
20: * This product includes software developed by the University of
21: * California, Berkeley and its contributors.
22: * 4. Neither the name of the University nor the names of its contributors
23: * may be used to endorse or promote products derived from this software
24: * without specific prior written permission.
25: *
26: * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29: * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36: * SUCH DAMAGE.
37: */
38:
1.6 christos 39: #include <sys/cdefs.h>
1.1 cgd 40: #if defined(LIBC_SCCS) && !defined(lint)
1.4 cgd 41: #if 0
1.8 perry 42: static char sccsid[] = "@(#)getcwd.c 8.5 (Berkeley) 2/7/95";
1.4 cgd 43: #else
1.31 ! itojun 44: __RCSID("$NetBSD: getcwd.c,v 1.30 2003/08/03 04:14:00 itojun Exp $");
1.4 cgd 45: #endif
1.1 cgd 46: #endif /* LIBC_SCCS and not lint */
47:
1.7 jtc 48: #include "namespace.h"
1.1 cgd 49: #include <sys/param.h>
50: #include <sys/stat.h>
1.8 perry 51:
1.22 lukem 52: #include <assert.h>
1.8 perry 53: #include <dirent.h>
1.1 cgd 54: #include <errno.h>
1.8 perry 55: #include <fcntl.h>
1.1 cgd 56: #include <stdio.h>
57: #include <stdlib.h>
58: #include <string.h>
59: #include <unistd.h>
1.17 sommerfe 60:
61: #include "extern.h"
1.7 jtc 62:
63: #ifdef __weak_alias
1.24 mycroft 64: __weak_alias(getcwd,_getcwd)
65: __weak_alias(realpath,_realpath)
1.7 jtc 66: #endif
1.1 cgd 67:
68: #define ISDOT(dp) \
69: (dp->d_name[0] == '.' && (dp->d_name[1] == '\0' || \
1.6 christos 70: (dp->d_name[1] == '.' && dp->d_name[2] == '\0')))
1.1 cgd 71:
1.8 perry 72:
1.15 christos 73: #if defined(__SVR4) || defined(__svr4__)
74: #define d_fileno d_ino
75: #endif
76:
1.8 perry 77: /*
78: * char *realpath(const char *path, char resolved_path[MAXPATHLEN]);
79: *
80: * Find the real name of path, by removing all ".", ".." and symlink
81: * components. Returns (resolved) on success, or (NULL) on failure,
82: * in which case the path which caused trouble is left in (resolved).
83: */
84: char *
85: realpath(path, resolved)
86: const char *path;
87: char *resolved;
88: {
89: struct stat sb;
1.21 fvdl 90: int fd, n, rootd, serrno, nlnk = 0;
1.8 perry 91: char *p, *q, wbuf[MAXPATHLEN];
1.22 lukem 92:
93: _DIAGASSERT(path != NULL);
94: _DIAGASSERT(resolved != NULL);
1.8 perry 95:
96: /* Save the starting point. */
97: if ((fd = open(".", O_RDONLY)) < 0) {
1.28 itojun 98: (void)strlcpy(resolved, ".", MAXPATHLEN);
1.8 perry 99: return (NULL);
100: }
101:
102: /*
103: * Find the dirname and basename from the path to be resolved.
104: * Change directory to the dirname component.
105: * lstat the basename part.
106: * if it is a symlink, read in the value and loop.
107: * if it is a directory, then change to that directory.
108: * get the current directory name and append the basename.
109: */
1.31 ! itojun 110: if (strlcpy(resolved, path, MAXPATHLEN) >= MAXPATHLEN) {
! 111: errno = ENAMETOOLONG;
! 112: goto err1;
! 113: }
1.8 perry 114: loop:
115: q = strrchr(resolved, '/');
116: if (q != NULL) {
117: p = q + 1;
118: if (q == resolved)
119: q = "/";
120: else {
121: do {
122: --q;
123: } while (q > resolved && *q == '/');
124: q[1] = '\0';
125: q = resolved;
126: }
127: if (chdir(q) < 0)
128: goto err1;
129: } else
130: p = resolved;
131:
132: /* Deal with the last component. */
133: if (lstat(p, &sb) == 0) {
134: if (S_ISLNK(sb.st_mode)) {
1.21 fvdl 135: if (nlnk++ >= MAXSYMLINKS) {
136: errno = ELOOP;
137: goto err1;
138: }
1.26 provos 139: n = readlink(p, resolved, MAXPATHLEN-1);
1.8 perry 140: if (n < 0)
141: goto err1;
142: resolved[n] = '\0';
143: goto loop;
144: }
145: if (S_ISDIR(sb.st_mode)) {
146: if (chdir(p) < 0)
147: goto err1;
148: p = "";
149: }
150: }
151:
152: /*
153: * Save the last component name and get the full pathname of
154: * the current directory.
155: */
1.31 ! itojun 156: if (strlcpy(wbuf, p, sizeof(wbuf)) >= sizeof(wbuf)) {
! 157: errno = ENAMETOOLONG;
! 158: goto err1;
! 159: }
1.8 perry 160:
161: /*
162: * Call the inernal internal version of getcwd which
163: * does a physical search rather than using the $PWD short-cut
164: */
1.12 lukem 165: if (getcwd(resolved, MAXPATHLEN) == 0)
1.8 perry 166: goto err1;
167:
168: /*
169: * Join the two strings together, ensuring that the right thing
170: * happens if the last component is empty, or the dirname is root.
171: */
172: if (resolved[0] == '/' && resolved[1] == '\0')
173: rootd = 1;
174: else
175: rootd = 0;
176:
177: if (*wbuf) {
1.29 itojun 178: if (strlen(resolved) + strlen(wbuf) + (rootd ? 0 : 1) + 1 >
179: MAXPATHLEN) {
1.8 perry 180: errno = ENAMETOOLONG;
181: goto err1;
182: }
183: if (rootd == 0)
1.31 ! itojun 184: if (strlcat(resolved, "/", MAXPATHLEN) >= MAXPATHLEN) {
! 185: errno = ENAMETOOLONG;
! 186: goto err1;
! 187: }
! 188: if (strlcat(resolved, wbuf, MAXPATHLEN) >= MAXPATHLEN) {
! 189: errno = ENAMETOOLONG;
! 190: goto err1;
! 191: }
1.8 perry 192: }
193:
194: /* Go back to where we came from. */
195: if (fchdir(fd) < 0) {
196: serrno = errno;
197: goto err2;
198: }
199:
200: /* It's okay if the close fails, what's an fd more or less? */
201: (void)close(fd);
202: return (resolved);
203:
204: err1: serrno = errno;
205: (void)fchdir(fd);
206: err2: (void)close(fd);
207: errno = serrno;
208: return (NULL);
209: }
210:
1.16 sommerfe 211: #ifdef OLD_GETCWD
212:
1.12 lukem 213: char *
214: getcwd(pt, size)
1.8 perry 215: char *pt;
216: size_t size;
217: {
1.10 perry 218: struct dirent *dp;
219: DIR *dir;
220: dev_t dev;
221: ino_t ino;
222: int first;
223: char *bpt, *bup;
1.1 cgd 224: struct stat s;
225: dev_t root_dev;
226: ino_t root_ino;
227: size_t ptsize, upsize;
228: int save_errno;
229: char *ept, *eup, *up;
1.15 christos 230: size_t dlen;
1.1 cgd 231:
232: /*
233: * If no buffer specified by the user, allocate one as necessary.
234: * If a buffer is specified, the size has to be non-zero. The path
235: * is built from the end of the buffer backwards.
236: */
237: if (pt) {
238: ptsize = 0;
239: if (!size) {
240: errno = EINVAL;
1.4 cgd 241: return (NULL);
1.1 cgd 242: }
243: ept = pt + size;
244: } else {
1.4 cgd 245: if ((pt = malloc(ptsize = 1024 - 4)) == NULL)
246: return (NULL);
1.1 cgd 247: ept = pt + ptsize;
248: }
249: bpt = ept - 1;
250: *bpt = '\0';
251:
252: /*
253: * Allocate bytes (1024 - malloc space) for the string of "../"'s.
254: * Should always be enough (it's 340 levels). If it's not, allocate
1.8 perry 255: * as necessary. Special case the first stat, it's ".", not "..".
1.1 cgd 256: */
1.4 cgd 257: if ((up = malloc(upsize = 1024 - 4)) == NULL)
1.1 cgd 258: goto err;
259: eup = up + MAXPATHLEN;
260: bup = up;
261: up[0] = '.';
262: up[1] = '\0';
263:
264: /* Save root values, so know when to stop. */
265: if (stat("/", &s))
266: goto err;
267: root_dev = s.st_dev;
268: root_ino = s.st_ino;
269:
270: errno = 0; /* XXX readdir has no error return. */
271:
272: for (first = 1;; first = 0) {
273: /* Stat the current level. */
274: if (lstat(up, &s))
275: goto err;
276:
277: /* Save current node values. */
278: ino = s.st_ino;
279: dev = s.st_dev;
280:
281: /* Check for reaching root. */
282: if (root_dev == dev && root_ino == ino) {
283: *--bpt = '/';
284: /*
285: * It's unclear that it's a requirement to copy the
286: * path to the beginning of the buffer, but it's always
287: * been that way and stuff would probably break.
288: */
1.14 perry 289: memmove(pt, bpt, (size_t)(ept - bpt));
1.1 cgd 290: free(up);
1.4 cgd 291: return (pt);
1.1 cgd 292: }
293:
294: /*
295: * Build pointer to the parent directory, allocating memory
296: * as necessary. Max length is 3 for "../", the largest
297: * possible component name, plus a trailing NULL.
298: */
299: if (bup + 3 + MAXNAMLEN + 1 >= eup) {
1.4 cgd 300: if ((up = realloc(up, upsize *= 2)) == NULL)
1.1 cgd 301: goto err;
1.4 cgd 302: bup = up;
1.1 cgd 303: eup = up + upsize;
304: }
305: *bup++ = '.';
306: *bup++ = '.';
307: *bup = '\0';
308:
309: /* Open and stat parent directory. */
310: if (!(dir = opendir(up)) || fstat(dirfd(dir), &s))
311: goto err;
312:
313: /* Add trailing slash for next directory. */
314: *bup++ = '/';
315:
316: /*
317: * If it's a mount point, have to stat each element because
318: * the inode number in the directory is for the entry in the
319: * parent directory, not the inode number of the mounted file.
320: */
321: save_errno = 0;
322: if (s.st_dev == dev) {
323: for (;;) {
324: if (!(dp = readdir(dir)))
325: goto notfound;
1.15 christos 326: if (dp->d_fileno == ino) {
1.19 christos 327: #if defined(__SVR4) || defined(__svr4__) || defined(__linux__)
1.15 christos 328: dlen = strlen(dp->d_name);
329: #else
330: dlen = dp->d_namlen;
331: #endif
1.1 cgd 332: break;
1.15 christos 333: }
1.1 cgd 334: }
335: } else
336: for (;;) {
337: if (!(dp = readdir(dir)))
338: goto notfound;
339: if (ISDOT(dp))
340: continue;
1.19 christos 341: #if defined(__SVR4) || defined(__svr4__) || defined(__linux__)
1.15 christos 342: dlen = strlen(dp->d_name);
343: #else
344: dlen = dp->d_namlen;
345: #endif
346: memmove(bup, dp->d_name, dlen + 1);
1.1 cgd 347:
348: /* Save the first error for later. */
349: if (lstat(up, &s)) {
350: if (!save_errno)
351: save_errno = errno;
352: errno = 0;
353: continue;
354: }
355: if (s.st_dev == dev && s.st_ino == ino)
356: break;
357: }
358:
359: /*
360: * Check for length of the current name, preceding slash,
361: * leading slash.
362: */
1.15 christos 363: if (bpt - pt <= dlen + (first ? 1 : 2)) {
1.1 cgd 364: size_t len, off;
365:
366: if (!ptsize) {
367: errno = ERANGE;
368: goto err;
369: }
370: off = bpt - pt;
371: len = ept - bpt;
1.4 cgd 372: if ((pt = realloc(pt, ptsize *= 2)) == NULL)
1.1 cgd 373: goto err;
374: bpt = pt + off;
375: ept = pt + ptsize;
1.14 perry 376: memmove(ept - len, bpt, len);
1.1 cgd 377: bpt = ept - len;
378: }
379: if (!first)
380: *--bpt = '/';
1.15 christos 381: bpt -= dlen;
382: memmove(bpt, dp->d_name, dlen);
1.1 cgd 383: (void)closedir(dir);
384:
385: /* Truncate any file name. */
386: *bup = '\0';
387: }
388:
389: notfound:
390: /*
391: * If readdir set errno, use it, not any saved error; otherwise,
392: * didn't find the current directory in its parent directory, set
393: * errno to ENOENT.
394: */
395: if (!errno)
396: errno = save_errno ? save_errno : ENOENT;
397: /* FALLTHROUGH */
398: err:
399: if (ptsize)
400: free(pt);
401: free(up);
1.4 cgd 402: return (NULL);
1.1 cgd 403: }
1.16 sommerfe 404:
405: #else /* New getcwd */
406:
407: char *
408: getcwd(pt, size)
409: char *pt;
410: size_t size;
411: {
1.18 christos 412: size_t ptsize, bufsize;
413: int len;
1.16 sommerfe 414:
415: /*
416: * If no buffer specified by the user, allocate one as necessary.
417: * If a buffer is specified, the size has to be non-zero. The path
418: * is built from the end of the buffer backwards.
419: */
420: if (pt) {
421: ptsize = 0;
422: if (!size) {
423: errno = EINVAL;
424: return (NULL);
425: }
426: bufsize = size;
427: } else {
428: if ((pt = malloc(ptsize = 1024 - 4)) == NULL)
429: return (NULL);
430: bufsize = ptsize;
431: }
1.18 christos 432: for (;;) {
1.16 sommerfe 433: len = __getcwd(pt, bufsize);
434: if ((len < 0) && (size == 0) && (errno == ERANGE)) {
1.20 sommerfe 435: if (ptsize > (MAXPATHLEN*4))
436: return NULL;
1.16 sommerfe 437: if ((pt = realloc(pt, ptsize *= 2)) == NULL)
438: return NULL;
439: bufsize = ptsize;
440: continue;
441: }
1.18 christos 442: break;
443: }
1.16 sommerfe 444: if (len < 0)
445: return NULL;
446: else
447: return pt;
448: }
449:
450: #endif
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