Annotation of src/lib/libc/gen/getcwd.c, Revision 1.17
1.17 ! sommerfe 1: /* $NetBSD: getcwd.c,v 1.16 1999/03/26 04:04:13 sommerfe 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
1.17 ! sommerfe 44: __RCSID("$NetBSD: getcwd.c,v 1.16 1999/03/26 04:04:13 sommerfe 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:
52: #include <dirent.h>
1.1 cgd 53: #include <errno.h>
1.8 perry 54: #include <fcntl.h>
1.1 cgd 55: #include <stdio.h>
56: #include <stdlib.h>
57: #include <string.h>
58: #include <unistd.h>
1.17 ! sommerfe 59:
! 60: #include "extern.h"
1.7 jtc 61:
62: #ifdef __weak_alias
63: __weak_alias(getcwd,_getcwd);
1.9 perry 64: __weak_alias(realpath,_realpath);
1.7 jtc 65: #endif
1.1 cgd 66:
67: #define ISDOT(dp) \
68: (dp->d_name[0] == '.' && (dp->d_name[1] == '\0' || \
1.6 christos 69: (dp->d_name[1] == '.' && dp->d_name[2] == '\0')))
1.1 cgd 70:
1.8 perry 71:
1.15 christos 72: #if defined(__SVR4) || defined(__svr4__)
73: #define d_fileno d_ino
74: #endif
75:
1.8 perry 76: /*
77: * char *realpath(const char *path, char resolved_path[MAXPATHLEN]);
78: *
79: * Find the real name of path, by removing all ".", ".." and symlink
80: * components. Returns (resolved) on success, or (NULL) on failure,
81: * in which case the path which caused trouble is left in (resolved).
82: */
83: char *
84: realpath(path, resolved)
85: const char *path;
86: char *resolved;
87: {
88: struct stat sb;
89: int fd, n, rootd, serrno;
90: char *p, *q, wbuf[MAXPATHLEN];
91:
92: /* Save the starting point. */
93: if ((fd = open(".", O_RDONLY)) < 0) {
94: (void)strcpy(resolved, ".");
95: return (NULL);
96: }
97:
98: /*
99: * Find the dirname and basename from the path to be resolved.
100: * Change directory to the dirname component.
101: * lstat the basename part.
102: * if it is a symlink, read in the value and loop.
103: * if it is a directory, then change to that directory.
104: * get the current directory name and append the basename.
105: */
106: (void)strncpy(resolved, path, MAXPATHLEN - 1);
107: resolved[MAXPATHLEN - 1] = '\0';
108: loop:
109: q = strrchr(resolved, '/');
110: if (q != NULL) {
111: p = q + 1;
112: if (q == resolved)
113: q = "/";
114: else {
115: do {
116: --q;
117: } while (q > resolved && *q == '/');
118: q[1] = '\0';
119: q = resolved;
120: }
121: if (chdir(q) < 0)
122: goto err1;
123: } else
124: p = resolved;
125:
126: /* Deal with the last component. */
127: if (lstat(p, &sb) == 0) {
128: if (S_ISLNK(sb.st_mode)) {
129: n = readlink(p, resolved, MAXPATHLEN);
130: if (n < 0)
131: goto err1;
132: resolved[n] = '\0';
133: goto loop;
134: }
135: if (S_ISDIR(sb.st_mode)) {
136: if (chdir(p) < 0)
137: goto err1;
138: p = "";
139: }
140: }
141:
142: /*
143: * Save the last component name and get the full pathname of
144: * the current directory.
145: */
1.9 perry 146: (void)strncpy(wbuf, p, (sizeof(wbuf) - 1));
1.8 perry 147:
148: /*
149: * Call the inernal internal version of getcwd which
150: * does a physical search rather than using the $PWD short-cut
151: */
1.12 lukem 152: if (getcwd(resolved, MAXPATHLEN) == 0)
1.8 perry 153: goto err1;
154:
155: /*
156: * Join the two strings together, ensuring that the right thing
157: * happens if the last component is empty, or the dirname is root.
158: */
159: if (resolved[0] == '/' && resolved[1] == '\0')
160: rootd = 1;
161: else
162: rootd = 0;
163:
164: if (*wbuf) {
165: if (strlen(resolved) + strlen(wbuf) + rootd + 1 > MAXPATHLEN) {
166: errno = ENAMETOOLONG;
167: goto err1;
168: }
169: if (rootd == 0)
1.9 perry 170: (void)strcat(resolved, "/"); /* XXX: strcat is safe */
171: (void)strcat(resolved, wbuf); /* XXX: strcat is safe */
1.8 perry 172: }
173:
174: /* Go back to where we came from. */
175: if (fchdir(fd) < 0) {
176: serrno = errno;
177: goto err2;
178: }
179:
180: /* It's okay if the close fails, what's an fd more or less? */
181: (void)close(fd);
182: return (resolved);
183:
184: err1: serrno = errno;
185: (void)fchdir(fd);
186: err2: (void)close(fd);
187: errno = serrno;
188: return (NULL);
189: }
190:
1.16 sommerfe 191: #ifdef OLD_GETCWD
192:
1.12 lukem 193: char *
194: getcwd(pt, size)
1.8 perry 195: char *pt;
196: size_t size;
197: {
1.10 perry 198: struct dirent *dp;
199: DIR *dir;
200: dev_t dev;
201: ino_t ino;
202: int first;
203: char *bpt, *bup;
1.1 cgd 204: struct stat s;
205: dev_t root_dev;
206: ino_t root_ino;
207: size_t ptsize, upsize;
208: int save_errno;
209: char *ept, *eup, *up;
1.15 christos 210: size_t dlen;
1.1 cgd 211:
212: /*
213: * If no buffer specified by the user, allocate one as necessary.
214: * If a buffer is specified, the size has to be non-zero. The path
215: * is built from the end of the buffer backwards.
216: */
217: if (pt) {
218: ptsize = 0;
219: if (!size) {
220: errno = EINVAL;
1.4 cgd 221: return (NULL);
1.1 cgd 222: }
223: ept = pt + size;
224: } else {
1.4 cgd 225: if ((pt = malloc(ptsize = 1024 - 4)) == NULL)
226: return (NULL);
1.1 cgd 227: ept = pt + ptsize;
228: }
229: bpt = ept - 1;
230: *bpt = '\0';
231:
232: /*
233: * Allocate bytes (1024 - malloc space) for the string of "../"'s.
234: * Should always be enough (it's 340 levels). If it's not, allocate
1.8 perry 235: * as necessary. Special case the first stat, it's ".", not "..".
1.1 cgd 236: */
1.4 cgd 237: if ((up = malloc(upsize = 1024 - 4)) == NULL)
1.1 cgd 238: goto err;
239: eup = up + MAXPATHLEN;
240: bup = up;
241: up[0] = '.';
242: up[1] = '\0';
243:
244: /* Save root values, so know when to stop. */
245: if (stat("/", &s))
246: goto err;
247: root_dev = s.st_dev;
248: root_ino = s.st_ino;
249:
250: errno = 0; /* XXX readdir has no error return. */
251:
252: for (first = 1;; first = 0) {
253: /* Stat the current level. */
254: if (lstat(up, &s))
255: goto err;
256:
257: /* Save current node values. */
258: ino = s.st_ino;
259: dev = s.st_dev;
260:
261: /* Check for reaching root. */
262: if (root_dev == dev && root_ino == ino) {
263: *--bpt = '/';
264: /*
265: * It's unclear that it's a requirement to copy the
266: * path to the beginning of the buffer, but it's always
267: * been that way and stuff would probably break.
268: */
1.14 perry 269: memmove(pt, bpt, (size_t)(ept - bpt));
1.1 cgd 270: free(up);
1.4 cgd 271: return (pt);
1.1 cgd 272: }
273:
274: /*
275: * Build pointer to the parent directory, allocating memory
276: * as necessary. Max length is 3 for "../", the largest
277: * possible component name, plus a trailing NULL.
278: */
279: if (bup + 3 + MAXNAMLEN + 1 >= eup) {
1.4 cgd 280: if ((up = realloc(up, upsize *= 2)) == NULL)
1.1 cgd 281: goto err;
1.4 cgd 282: bup = up;
1.1 cgd 283: eup = up + upsize;
284: }
285: *bup++ = '.';
286: *bup++ = '.';
287: *bup = '\0';
288:
289: /* Open and stat parent directory. */
290: if (!(dir = opendir(up)) || fstat(dirfd(dir), &s))
291: goto err;
292:
293: /* Add trailing slash for next directory. */
294: *bup++ = '/';
295:
296: /*
297: * If it's a mount point, have to stat each element because
298: * the inode number in the directory is for the entry in the
299: * parent directory, not the inode number of the mounted file.
300: */
301: save_errno = 0;
302: if (s.st_dev == dev) {
303: for (;;) {
304: if (!(dp = readdir(dir)))
305: goto notfound;
1.15 christos 306: if (dp->d_fileno == ino) {
307: #if defined(__SVR4) || defined(__svr4__)
308: dlen = strlen(dp->d_name);
309: #else
310: dlen = dp->d_namlen;
311: #endif
1.1 cgd 312: break;
1.15 christos 313: }
1.1 cgd 314: }
315: } else
316: for (;;) {
317: if (!(dp = readdir(dir)))
318: goto notfound;
319: if (ISDOT(dp))
320: continue;
1.15 christos 321: #if defined(__SVR4) || defined(__svr4__)
322: dlen = strlen(dp->d_name);
323: #else
324: dlen = dp->d_namlen;
325: #endif
326: memmove(bup, dp->d_name, dlen + 1);
1.1 cgd 327:
328: /* Save the first error for later. */
329: if (lstat(up, &s)) {
330: if (!save_errno)
331: save_errno = errno;
332: errno = 0;
333: continue;
334: }
335: if (s.st_dev == dev && s.st_ino == ino)
336: break;
337: }
338:
339: /*
340: * Check for length of the current name, preceding slash,
341: * leading slash.
342: */
1.15 christos 343: if (bpt - pt <= dlen + (first ? 1 : 2)) {
1.1 cgd 344: size_t len, off;
345:
346: if (!ptsize) {
347: errno = ERANGE;
348: goto err;
349: }
350: off = bpt - pt;
351: len = ept - bpt;
1.4 cgd 352: if ((pt = realloc(pt, ptsize *= 2)) == NULL)
1.1 cgd 353: goto err;
354: bpt = pt + off;
355: ept = pt + ptsize;
1.14 perry 356: memmove(ept - len, bpt, len);
1.1 cgd 357: bpt = ept - len;
358: }
359: if (!first)
360: *--bpt = '/';
1.15 christos 361: bpt -= dlen;
362: memmove(bpt, dp->d_name, dlen);
1.1 cgd 363: (void)closedir(dir);
364:
365: /* Truncate any file name. */
366: *bup = '\0';
367: }
368:
369: notfound:
370: /*
371: * If readdir set errno, use it, not any saved error; otherwise,
372: * didn't find the current directory in its parent directory, set
373: * errno to ENOENT.
374: */
375: if (!errno)
376: errno = save_errno ? save_errno : ENOENT;
377: /* FALLTHROUGH */
378: err:
379: if (ptsize)
380: free(pt);
381: free(up);
1.4 cgd 382: return (NULL);
1.1 cgd 383: }
1.16 sommerfe 384:
385: #else /* New getcwd */
386:
387: char *
388: getcwd(pt, size)
389: char *pt;
390: size_t size;
391: {
392: int ptsize, bufsize, len;
393:
394: /*
395: * If no buffer specified by the user, allocate one as necessary.
396: * If a buffer is specified, the size has to be non-zero. The path
397: * is built from the end of the buffer backwards.
398: */
399: if (pt) {
400: ptsize = 0;
401: if (!size) {
402: errno = EINVAL;
403: return (NULL);
404: }
405: bufsize = size;
406: } else {
407: if ((pt = malloc(ptsize = 1024 - 4)) == NULL)
408: return (NULL);
409: bufsize = ptsize;
410: }
411: do {
412: len = __getcwd(pt, bufsize);
413: if ((len < 0) && (size == 0) && (errno == ERANGE)) {
414: if ((pt = realloc(pt, ptsize *= 2)) == NULL)
415: return NULL;
416: bufsize = ptsize;
417: continue;
418: }
419: } while (0);
420: if (len < 0)
421: return NULL;
422: else
423: return pt;
424: }
425:
426: #endif
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