Annotation of src/lib/libc/gen/getcwd.c, Revision 1.25.2.1
1.25.2.1! grant 1: /* $NetBSD: getcwd.c,v 1.25 2002/04/16 19:08:43 groo 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
1.25.2.1! grant 44: __RCSID("$NetBSD: getcwd.c,v 1.25 2002/04/16 19:08:43 groo 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) {
98: (void)strcpy(resolved, ".");
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: */
110: (void)strncpy(resolved, path, MAXPATHLEN - 1);
111: resolved[MAXPATHLEN - 1] = '\0';
112: loop:
113: q = strrchr(resolved, '/');
114: if (q != NULL) {
115: p = q + 1;
116: if (q == resolved)
117: q = "/";
118: else {
119: do {
120: --q;
121: } while (q > resolved && *q == '/');
122: q[1] = '\0';
123: q = resolved;
124: }
125: if (chdir(q) < 0)
126: goto err1;
127: } else
128: p = resolved;
129:
130: /* Deal with the last component. */
131: if (lstat(p, &sb) == 0) {
132: if (S_ISLNK(sb.st_mode)) {
1.21 fvdl 133: if (nlnk++ >= MAXSYMLINKS) {
134: errno = ELOOP;
135: goto err1;
136: }
1.8 perry 137: n = readlink(p, resolved, MAXPATHLEN);
138: if (n < 0)
139: goto err1;
140: resolved[n] = '\0';
141: goto loop;
142: }
143: if (S_ISDIR(sb.st_mode)) {
144: if (chdir(p) < 0)
145: goto err1;
146: p = "";
147: }
148: }
149:
150: /*
151: * Save the last component name and get the full pathname of
152: * the current directory.
153: */
1.25 groo 154: (void)strlcpy(wbuf, p, sizeof(wbuf));
1.8 perry 155:
156: /*
157: * Call the inernal internal version of getcwd which
158: * does a physical search rather than using the $PWD short-cut
159: */
1.12 lukem 160: if (getcwd(resolved, MAXPATHLEN) == 0)
1.8 perry 161: goto err1;
162:
163: /*
164: * Join the two strings together, ensuring that the right thing
165: * happens if the last component is empty, or the dirname is root.
166: */
167: if (resolved[0] == '/' && resolved[1] == '\0')
168: rootd = 1;
169: else
170: rootd = 0;
171:
172: if (*wbuf) {
1.25.2.1! grant 173: if (strlen(resolved) + strlen(wbuf) + (rootd ? 0 : 1) + 1 >
! 174: MAXPATHLEN) {
1.8 perry 175: errno = ENAMETOOLONG;
176: goto err1;
177: }
178: if (rootd == 0)
1.9 perry 179: (void)strcat(resolved, "/"); /* XXX: strcat is safe */
180: (void)strcat(resolved, wbuf); /* XXX: strcat is safe */
1.8 perry 181: }
182:
183: /* Go back to where we came from. */
184: if (fchdir(fd) < 0) {
185: serrno = errno;
186: goto err2;
187: }
188:
189: /* It's okay if the close fails, what's an fd more or less? */
190: (void)close(fd);
191: return (resolved);
192:
193: err1: serrno = errno;
194: (void)fchdir(fd);
195: err2: (void)close(fd);
196: errno = serrno;
197: return (NULL);
198: }
199:
1.16 sommerfe 200: #ifdef OLD_GETCWD
201:
1.12 lukem 202: char *
203: getcwd(pt, size)
1.8 perry 204: char *pt;
205: size_t size;
206: {
1.10 perry 207: struct dirent *dp;
208: DIR *dir;
209: dev_t dev;
210: ino_t ino;
211: int first;
212: char *bpt, *bup;
1.1 cgd 213: struct stat s;
214: dev_t root_dev;
215: ino_t root_ino;
216: size_t ptsize, upsize;
217: int save_errno;
218: char *ept, *eup, *up;
1.15 christos 219: size_t dlen;
1.1 cgd 220:
221: /*
222: * If no buffer specified by the user, allocate one as necessary.
223: * If a buffer is specified, the size has to be non-zero. The path
224: * is built from the end of the buffer backwards.
225: */
226: if (pt) {
227: ptsize = 0;
228: if (!size) {
229: errno = EINVAL;
1.4 cgd 230: return (NULL);
1.1 cgd 231: }
232: ept = pt + size;
233: } else {
1.4 cgd 234: if ((pt = malloc(ptsize = 1024 - 4)) == NULL)
235: return (NULL);
1.1 cgd 236: ept = pt + ptsize;
237: }
238: bpt = ept - 1;
239: *bpt = '\0';
240:
241: /*
242: * Allocate bytes (1024 - malloc space) for the string of "../"'s.
243: * Should always be enough (it's 340 levels). If it's not, allocate
1.8 perry 244: * as necessary. Special case the first stat, it's ".", not "..".
1.1 cgd 245: */
1.4 cgd 246: if ((up = malloc(upsize = 1024 - 4)) == NULL)
1.1 cgd 247: goto err;
248: eup = up + MAXPATHLEN;
249: bup = up;
250: up[0] = '.';
251: up[1] = '\0';
252:
253: /* Save root values, so know when to stop. */
254: if (stat("/", &s))
255: goto err;
256: root_dev = s.st_dev;
257: root_ino = s.st_ino;
258:
259: errno = 0; /* XXX readdir has no error return. */
260:
261: for (first = 1;; first = 0) {
262: /* Stat the current level. */
263: if (lstat(up, &s))
264: goto err;
265:
266: /* Save current node values. */
267: ino = s.st_ino;
268: dev = s.st_dev;
269:
270: /* Check for reaching root. */
271: if (root_dev == dev && root_ino == ino) {
272: *--bpt = '/';
273: /*
274: * It's unclear that it's a requirement to copy the
275: * path to the beginning of the buffer, but it's always
276: * been that way and stuff would probably break.
277: */
1.14 perry 278: memmove(pt, bpt, (size_t)(ept - bpt));
1.1 cgd 279: free(up);
1.4 cgd 280: return (pt);
1.1 cgd 281: }
282:
283: /*
284: * Build pointer to the parent directory, allocating memory
285: * as necessary. Max length is 3 for "../", the largest
286: * possible component name, plus a trailing NULL.
287: */
288: if (bup + 3 + MAXNAMLEN + 1 >= eup) {
1.4 cgd 289: if ((up = realloc(up, upsize *= 2)) == NULL)
1.1 cgd 290: goto err;
1.4 cgd 291: bup = up;
1.1 cgd 292: eup = up + upsize;
293: }
294: *bup++ = '.';
295: *bup++ = '.';
296: *bup = '\0';
297:
298: /* Open and stat parent directory. */
299: if (!(dir = opendir(up)) || fstat(dirfd(dir), &s))
300: goto err;
301:
302: /* Add trailing slash for next directory. */
303: *bup++ = '/';
304:
305: /*
306: * If it's a mount point, have to stat each element because
307: * the inode number in the directory is for the entry in the
308: * parent directory, not the inode number of the mounted file.
309: */
310: save_errno = 0;
311: if (s.st_dev == dev) {
312: for (;;) {
313: if (!(dp = readdir(dir)))
314: goto notfound;
1.15 christos 315: if (dp->d_fileno == ino) {
1.19 christos 316: #if defined(__SVR4) || defined(__svr4__) || defined(__linux__)
1.15 christos 317: dlen = strlen(dp->d_name);
318: #else
319: dlen = dp->d_namlen;
320: #endif
1.1 cgd 321: break;
1.15 christos 322: }
1.1 cgd 323: }
324: } else
325: for (;;) {
326: if (!(dp = readdir(dir)))
327: goto notfound;
328: if (ISDOT(dp))
329: continue;
1.19 christos 330: #if defined(__SVR4) || defined(__svr4__) || defined(__linux__)
1.15 christos 331: dlen = strlen(dp->d_name);
332: #else
333: dlen = dp->d_namlen;
334: #endif
335: memmove(bup, dp->d_name, dlen + 1);
1.1 cgd 336:
337: /* Save the first error for later. */
338: if (lstat(up, &s)) {
339: if (!save_errno)
340: save_errno = errno;
341: errno = 0;
342: continue;
343: }
344: if (s.st_dev == dev && s.st_ino == ino)
345: break;
346: }
347:
348: /*
349: * Check for length of the current name, preceding slash,
350: * leading slash.
351: */
1.15 christos 352: if (bpt - pt <= dlen + (first ? 1 : 2)) {
1.1 cgd 353: size_t len, off;
354:
355: if (!ptsize) {
356: errno = ERANGE;
357: goto err;
358: }
359: off = bpt - pt;
360: len = ept - bpt;
1.4 cgd 361: if ((pt = realloc(pt, ptsize *= 2)) == NULL)
1.1 cgd 362: goto err;
363: bpt = pt + off;
364: ept = pt + ptsize;
1.14 perry 365: memmove(ept - len, bpt, len);
1.1 cgd 366: bpt = ept - len;
367: }
368: if (!first)
369: *--bpt = '/';
1.15 christos 370: bpt -= dlen;
371: memmove(bpt, dp->d_name, dlen);
1.1 cgd 372: (void)closedir(dir);
373:
374: /* Truncate any file name. */
375: *bup = '\0';
376: }
377:
378: notfound:
379: /*
380: * If readdir set errno, use it, not any saved error; otherwise,
381: * didn't find the current directory in its parent directory, set
382: * errno to ENOENT.
383: */
384: if (!errno)
385: errno = save_errno ? save_errno : ENOENT;
386: /* FALLTHROUGH */
387: err:
388: if (ptsize)
389: free(pt);
390: free(up);
1.4 cgd 391: return (NULL);
1.1 cgd 392: }
1.16 sommerfe 393:
394: #else /* New getcwd */
395:
396: char *
397: getcwd(pt, size)
398: char *pt;
399: size_t size;
400: {
1.18 christos 401: size_t ptsize, bufsize;
402: int len;
1.16 sommerfe 403:
404: /*
405: * If no buffer specified by the user, allocate one as necessary.
406: * If a buffer is specified, the size has to be non-zero. The path
407: * is built from the end of the buffer backwards.
408: */
409: if (pt) {
410: ptsize = 0;
411: if (!size) {
412: errno = EINVAL;
413: return (NULL);
414: }
415: bufsize = size;
416: } else {
417: if ((pt = malloc(ptsize = 1024 - 4)) == NULL)
418: return (NULL);
419: bufsize = ptsize;
420: }
1.18 christos 421: for (;;) {
1.16 sommerfe 422: len = __getcwd(pt, bufsize);
423: if ((len < 0) && (size == 0) && (errno == ERANGE)) {
1.20 sommerfe 424: if (ptsize > (MAXPATHLEN*4))
425: return NULL;
1.16 sommerfe 426: if ((pt = realloc(pt, ptsize *= 2)) == NULL)
427: return NULL;
428: bufsize = ptsize;
429: continue;
430: }
1.18 christos 431: break;
432: }
1.16 sommerfe 433: if (len < 0)
434: return NULL;
435: else
436: return pt;
437: }
438:
439: #endif
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