Annotation of src/lib/libc/gen/getcwd.c, Revision 1.28
1.28 ! itojun 1: /* $NetBSD: getcwd.c,v 1.27 2002/11/17 01:51:24 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
1.28 ! itojun 44: __RCSID("$NetBSD: getcwd.c,v 1.27 2002/11/17 01:51:24 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: */
1.27 itojun 110: (void)strlcpy(resolved, path, MAXPATHLEN);
1.8 perry 111: loop:
112: q = strrchr(resolved, '/');
113: if (q != NULL) {
114: p = q + 1;
115: if (q == resolved)
116: q = "/";
117: else {
118: do {
119: --q;
120: } while (q > resolved && *q == '/');
121: q[1] = '\0';
122: q = resolved;
123: }
124: if (chdir(q) < 0)
125: goto err1;
126: } else
127: p = resolved;
128:
129: /* Deal with the last component. */
130: if (lstat(p, &sb) == 0) {
131: if (S_ISLNK(sb.st_mode)) {
1.21 fvdl 132: if (nlnk++ >= MAXSYMLINKS) {
133: errno = ELOOP;
134: goto err1;
135: }
1.26 provos 136: n = readlink(p, resolved, MAXPATHLEN-1);
1.8 perry 137: if (n < 0)
138: goto err1;
139: resolved[n] = '\0';
140: goto loop;
141: }
142: if (S_ISDIR(sb.st_mode)) {
143: if (chdir(p) < 0)
144: goto err1;
145: p = "";
146: }
147: }
148:
149: /*
150: * Save the last component name and get the full pathname of
151: * the current directory.
152: */
1.25 groo 153: (void)strlcpy(wbuf, p, sizeof(wbuf));
1.8 perry 154:
155: /*
156: * Call the inernal internal version of getcwd which
157: * does a physical search rather than using the $PWD short-cut
158: */
1.12 lukem 159: if (getcwd(resolved, MAXPATHLEN) == 0)
1.8 perry 160: goto err1;
161:
162: /*
163: * Join the two strings together, ensuring that the right thing
164: * happens if the last component is empty, or the dirname is root.
165: */
166: if (resolved[0] == '/' && resolved[1] == '\0')
167: rootd = 1;
168: else
169: rootd = 0;
170:
171: if (*wbuf) {
172: if (strlen(resolved) + strlen(wbuf) + rootd + 1 > MAXPATHLEN) {
173: errno = ENAMETOOLONG;
174: goto err1;
175: }
176: if (rootd == 0)
1.9 perry 177: (void)strcat(resolved, "/"); /* XXX: strcat is safe */
178: (void)strcat(resolved, wbuf); /* XXX: strcat is safe */
1.8 perry 179: }
180:
181: /* Go back to where we came from. */
182: if (fchdir(fd) < 0) {
183: serrno = errno;
184: goto err2;
185: }
186:
187: /* It's okay if the close fails, what's an fd more or less? */
188: (void)close(fd);
189: return (resolved);
190:
191: err1: serrno = errno;
192: (void)fchdir(fd);
193: err2: (void)close(fd);
194: errno = serrno;
195: return (NULL);
196: }
197:
1.16 sommerfe 198: #ifdef OLD_GETCWD
199:
1.12 lukem 200: char *
201: getcwd(pt, size)
1.8 perry 202: char *pt;
203: size_t size;
204: {
1.10 perry 205: struct dirent *dp;
206: DIR *dir;
207: dev_t dev;
208: ino_t ino;
209: int first;
210: char *bpt, *bup;
1.1 cgd 211: struct stat s;
212: dev_t root_dev;
213: ino_t root_ino;
214: size_t ptsize, upsize;
215: int save_errno;
216: char *ept, *eup, *up;
1.15 christos 217: size_t dlen;
1.1 cgd 218:
219: /*
220: * If no buffer specified by the user, allocate one as necessary.
221: * If a buffer is specified, the size has to be non-zero. The path
222: * is built from the end of the buffer backwards.
223: */
224: if (pt) {
225: ptsize = 0;
226: if (!size) {
227: errno = EINVAL;
1.4 cgd 228: return (NULL);
1.1 cgd 229: }
230: ept = pt + size;
231: } else {
1.4 cgd 232: if ((pt = malloc(ptsize = 1024 - 4)) == NULL)
233: return (NULL);
1.1 cgd 234: ept = pt + ptsize;
235: }
236: bpt = ept - 1;
237: *bpt = '\0';
238:
239: /*
240: * Allocate bytes (1024 - malloc space) for the string of "../"'s.
241: * Should always be enough (it's 340 levels). If it's not, allocate
1.8 perry 242: * as necessary. Special case the first stat, it's ".", not "..".
1.1 cgd 243: */
1.4 cgd 244: if ((up = malloc(upsize = 1024 - 4)) == NULL)
1.1 cgd 245: goto err;
246: eup = up + MAXPATHLEN;
247: bup = up;
248: up[0] = '.';
249: up[1] = '\0';
250:
251: /* Save root values, so know when to stop. */
252: if (stat("/", &s))
253: goto err;
254: root_dev = s.st_dev;
255: root_ino = s.st_ino;
256:
257: errno = 0; /* XXX readdir has no error return. */
258:
259: for (first = 1;; first = 0) {
260: /* Stat the current level. */
261: if (lstat(up, &s))
262: goto err;
263:
264: /* Save current node values. */
265: ino = s.st_ino;
266: dev = s.st_dev;
267:
268: /* Check for reaching root. */
269: if (root_dev == dev && root_ino == ino) {
270: *--bpt = '/';
271: /*
272: * It's unclear that it's a requirement to copy the
273: * path to the beginning of the buffer, but it's always
274: * been that way and stuff would probably break.
275: */
1.14 perry 276: memmove(pt, bpt, (size_t)(ept - bpt));
1.1 cgd 277: free(up);
1.4 cgd 278: return (pt);
1.1 cgd 279: }
280:
281: /*
282: * Build pointer to the parent directory, allocating memory
283: * as necessary. Max length is 3 for "../", the largest
284: * possible component name, plus a trailing NULL.
285: */
286: if (bup + 3 + MAXNAMLEN + 1 >= eup) {
1.4 cgd 287: if ((up = realloc(up, upsize *= 2)) == NULL)
1.1 cgd 288: goto err;
1.4 cgd 289: bup = up;
1.1 cgd 290: eup = up + upsize;
291: }
292: *bup++ = '.';
293: *bup++ = '.';
294: *bup = '\0';
295:
296: /* Open and stat parent directory. */
297: if (!(dir = opendir(up)) || fstat(dirfd(dir), &s))
298: goto err;
299:
300: /* Add trailing slash for next directory. */
301: *bup++ = '/';
302:
303: /*
304: * If it's a mount point, have to stat each element because
305: * the inode number in the directory is for the entry in the
306: * parent directory, not the inode number of the mounted file.
307: */
308: save_errno = 0;
309: if (s.st_dev == dev) {
310: for (;;) {
311: if (!(dp = readdir(dir)))
312: goto notfound;
1.15 christos 313: if (dp->d_fileno == ino) {
1.19 christos 314: #if defined(__SVR4) || defined(__svr4__) || defined(__linux__)
1.15 christos 315: dlen = strlen(dp->d_name);
316: #else
317: dlen = dp->d_namlen;
318: #endif
1.1 cgd 319: break;
1.15 christos 320: }
1.1 cgd 321: }
322: } else
323: for (;;) {
324: if (!(dp = readdir(dir)))
325: goto notfound;
326: if (ISDOT(dp))
327: continue;
1.19 christos 328: #if defined(__SVR4) || defined(__svr4__) || defined(__linux__)
1.15 christos 329: dlen = strlen(dp->d_name);
330: #else
331: dlen = dp->d_namlen;
332: #endif
333: memmove(bup, dp->d_name, dlen + 1);
1.1 cgd 334:
335: /* Save the first error for later. */
336: if (lstat(up, &s)) {
337: if (!save_errno)
338: save_errno = errno;
339: errno = 0;
340: continue;
341: }
342: if (s.st_dev == dev && s.st_ino == ino)
343: break;
344: }
345:
346: /*
347: * Check for length of the current name, preceding slash,
348: * leading slash.
349: */
1.15 christos 350: if (bpt - pt <= dlen + (first ? 1 : 2)) {
1.1 cgd 351: size_t len, off;
352:
353: if (!ptsize) {
354: errno = ERANGE;
355: goto err;
356: }
357: off = bpt - pt;
358: len = ept - bpt;
1.4 cgd 359: if ((pt = realloc(pt, ptsize *= 2)) == NULL)
1.1 cgd 360: goto err;
361: bpt = pt + off;
362: ept = pt + ptsize;
1.14 perry 363: memmove(ept - len, bpt, len);
1.1 cgd 364: bpt = ept - len;
365: }
366: if (!first)
367: *--bpt = '/';
1.15 christos 368: bpt -= dlen;
369: memmove(bpt, dp->d_name, dlen);
1.1 cgd 370: (void)closedir(dir);
371:
372: /* Truncate any file name. */
373: *bup = '\0';
374: }
375:
376: notfound:
377: /*
378: * If readdir set errno, use it, not any saved error; otherwise,
379: * didn't find the current directory in its parent directory, set
380: * errno to ENOENT.
381: */
382: if (!errno)
383: errno = save_errno ? save_errno : ENOENT;
384: /* FALLTHROUGH */
385: err:
386: if (ptsize)
387: free(pt);
388: free(up);
1.4 cgd 389: return (NULL);
1.1 cgd 390: }
1.16 sommerfe 391:
392: #else /* New getcwd */
393:
394: char *
395: getcwd(pt, size)
396: char *pt;
397: size_t size;
398: {
1.18 christos 399: size_t ptsize, bufsize;
400: int len;
1.16 sommerfe 401:
402: /*
403: * If no buffer specified by the user, allocate one as necessary.
404: * If a buffer is specified, the size has to be non-zero. The path
405: * is built from the end of the buffer backwards.
406: */
407: if (pt) {
408: ptsize = 0;
409: if (!size) {
410: errno = EINVAL;
411: return (NULL);
412: }
413: bufsize = size;
414: } else {
415: if ((pt = malloc(ptsize = 1024 - 4)) == NULL)
416: return (NULL);
417: bufsize = ptsize;
418: }
1.18 christos 419: for (;;) {
1.16 sommerfe 420: len = __getcwd(pt, bufsize);
421: if ((len < 0) && (size == 0) && (errno == ERANGE)) {
1.20 sommerfe 422: if (ptsize > (MAXPATHLEN*4))
423: return NULL;
1.16 sommerfe 424: if ((pt = realloc(pt, ptsize *= 2)) == NULL)
425: return NULL;
426: bufsize = ptsize;
427: continue;
428: }
1.18 christos 429: break;
430: }
1.16 sommerfe 431: if (len < 0)
432: return NULL;
433: else
434: return pt;
435: }
436:
437: #endif
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