Annotation of src/lib/libc/gen/getcwd.c, Revision 1.21
1.21 ! fvdl 1: /* $NetBSD: getcwd.c,v 1.20 1999/07/11 18:01:46 sommerfeld 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
1.21 ! fvdl 44: __RCSID("$NetBSD: getcwd.c,v 1.20 1999/07/11 18:01:46 sommerfeld 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;
1.21 ! fvdl 89: int fd, n, rootd, serrno, nlnk = 0;
1.8 perry 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)) {
1.21 ! fvdl 129: if (nlnk++ >= MAXSYMLINKS) {
! 130: errno = ELOOP;
! 131: goto err1;
! 132: }
1.8 perry 133: n = readlink(p, resolved, MAXPATHLEN);
134: if (n < 0)
135: goto err1;
136: resolved[n] = '\0';
137: goto loop;
138: }
139: if (S_ISDIR(sb.st_mode)) {
140: if (chdir(p) < 0)
141: goto err1;
142: p = "";
143: }
144: }
145:
146: /*
147: * Save the last component name and get the full pathname of
148: * the current directory.
149: */
1.9 perry 150: (void)strncpy(wbuf, p, (sizeof(wbuf) - 1));
1.8 perry 151:
152: /*
153: * Call the inernal internal version of getcwd which
154: * does a physical search rather than using the $PWD short-cut
155: */
1.12 lukem 156: if (getcwd(resolved, MAXPATHLEN) == 0)
1.8 perry 157: goto err1;
158:
159: /*
160: * Join the two strings together, ensuring that the right thing
161: * happens if the last component is empty, or the dirname is root.
162: */
163: if (resolved[0] == '/' && resolved[1] == '\0')
164: rootd = 1;
165: else
166: rootd = 0;
167:
168: if (*wbuf) {
169: if (strlen(resolved) + strlen(wbuf) + rootd + 1 > MAXPATHLEN) {
170: errno = ENAMETOOLONG;
171: goto err1;
172: }
173: if (rootd == 0)
1.9 perry 174: (void)strcat(resolved, "/"); /* XXX: strcat is safe */
175: (void)strcat(resolved, wbuf); /* XXX: strcat is safe */
1.8 perry 176: }
177:
178: /* Go back to where we came from. */
179: if (fchdir(fd) < 0) {
180: serrno = errno;
181: goto err2;
182: }
183:
184: /* It's okay if the close fails, what's an fd more or less? */
185: (void)close(fd);
186: return (resolved);
187:
188: err1: serrno = errno;
189: (void)fchdir(fd);
190: err2: (void)close(fd);
191: errno = serrno;
192: return (NULL);
193: }
194:
1.16 sommerfe 195: #ifdef OLD_GETCWD
196:
1.12 lukem 197: char *
198: getcwd(pt, size)
1.8 perry 199: char *pt;
200: size_t size;
201: {
1.10 perry 202: struct dirent *dp;
203: DIR *dir;
204: dev_t dev;
205: ino_t ino;
206: int first;
207: char *bpt, *bup;
1.1 cgd 208: struct stat s;
209: dev_t root_dev;
210: ino_t root_ino;
211: size_t ptsize, upsize;
212: int save_errno;
213: char *ept, *eup, *up;
1.15 christos 214: size_t dlen;
1.1 cgd 215:
216: /*
217: * If no buffer specified by the user, allocate one as necessary.
218: * If a buffer is specified, the size has to be non-zero. The path
219: * is built from the end of the buffer backwards.
220: */
221: if (pt) {
222: ptsize = 0;
223: if (!size) {
224: errno = EINVAL;
1.4 cgd 225: return (NULL);
1.1 cgd 226: }
227: ept = pt + size;
228: } else {
1.4 cgd 229: if ((pt = malloc(ptsize = 1024 - 4)) == NULL)
230: return (NULL);
1.1 cgd 231: ept = pt + ptsize;
232: }
233: bpt = ept - 1;
234: *bpt = '\0';
235:
236: /*
237: * Allocate bytes (1024 - malloc space) for the string of "../"'s.
238: * Should always be enough (it's 340 levels). If it's not, allocate
1.8 perry 239: * as necessary. Special case the first stat, it's ".", not "..".
1.1 cgd 240: */
1.4 cgd 241: if ((up = malloc(upsize = 1024 - 4)) == NULL)
1.1 cgd 242: goto err;
243: eup = up + MAXPATHLEN;
244: bup = up;
245: up[0] = '.';
246: up[1] = '\0';
247:
248: /* Save root values, so know when to stop. */
249: if (stat("/", &s))
250: goto err;
251: root_dev = s.st_dev;
252: root_ino = s.st_ino;
253:
254: errno = 0; /* XXX readdir has no error return. */
255:
256: for (first = 1;; first = 0) {
257: /* Stat the current level. */
258: if (lstat(up, &s))
259: goto err;
260:
261: /* Save current node values. */
262: ino = s.st_ino;
263: dev = s.st_dev;
264:
265: /* Check for reaching root. */
266: if (root_dev == dev && root_ino == ino) {
267: *--bpt = '/';
268: /*
269: * It's unclear that it's a requirement to copy the
270: * path to the beginning of the buffer, but it's always
271: * been that way and stuff would probably break.
272: */
1.14 perry 273: memmove(pt, bpt, (size_t)(ept - bpt));
1.1 cgd 274: free(up);
1.4 cgd 275: return (pt);
1.1 cgd 276: }
277:
278: /*
279: * Build pointer to the parent directory, allocating memory
280: * as necessary. Max length is 3 for "../", the largest
281: * possible component name, plus a trailing NULL.
282: */
283: if (bup + 3 + MAXNAMLEN + 1 >= eup) {
1.4 cgd 284: if ((up = realloc(up, upsize *= 2)) == NULL)
1.1 cgd 285: goto err;
1.4 cgd 286: bup = up;
1.1 cgd 287: eup = up + upsize;
288: }
289: *bup++ = '.';
290: *bup++ = '.';
291: *bup = '\0';
292:
293: /* Open and stat parent directory. */
294: if (!(dir = opendir(up)) || fstat(dirfd(dir), &s))
295: goto err;
296:
297: /* Add trailing slash for next directory. */
298: *bup++ = '/';
299:
300: /*
301: * If it's a mount point, have to stat each element because
302: * the inode number in the directory is for the entry in the
303: * parent directory, not the inode number of the mounted file.
304: */
305: save_errno = 0;
306: if (s.st_dev == dev) {
307: for (;;) {
308: if (!(dp = readdir(dir)))
309: goto notfound;
1.15 christos 310: if (dp->d_fileno == ino) {
1.19 christos 311: #if defined(__SVR4) || defined(__svr4__) || defined(__linux__)
1.15 christos 312: dlen = strlen(dp->d_name);
313: #else
314: dlen = dp->d_namlen;
315: #endif
1.1 cgd 316: break;
1.15 christos 317: }
1.1 cgd 318: }
319: } else
320: for (;;) {
321: if (!(dp = readdir(dir)))
322: goto notfound;
323: if (ISDOT(dp))
324: continue;
1.19 christos 325: #if defined(__SVR4) || defined(__svr4__) || defined(__linux__)
1.15 christos 326: dlen = strlen(dp->d_name);
327: #else
328: dlen = dp->d_namlen;
329: #endif
330: memmove(bup, dp->d_name, dlen + 1);
1.1 cgd 331:
332: /* Save the first error for later. */
333: if (lstat(up, &s)) {
334: if (!save_errno)
335: save_errno = errno;
336: errno = 0;
337: continue;
338: }
339: if (s.st_dev == dev && s.st_ino == ino)
340: break;
341: }
342:
343: /*
344: * Check for length of the current name, preceding slash,
345: * leading slash.
346: */
1.15 christos 347: if (bpt - pt <= dlen + (first ? 1 : 2)) {
1.1 cgd 348: size_t len, off;
349:
350: if (!ptsize) {
351: errno = ERANGE;
352: goto err;
353: }
354: off = bpt - pt;
355: len = ept - bpt;
1.4 cgd 356: if ((pt = realloc(pt, ptsize *= 2)) == NULL)
1.1 cgd 357: goto err;
358: bpt = pt + off;
359: ept = pt + ptsize;
1.14 perry 360: memmove(ept - len, bpt, len);
1.1 cgd 361: bpt = ept - len;
362: }
363: if (!first)
364: *--bpt = '/';
1.15 christos 365: bpt -= dlen;
366: memmove(bpt, dp->d_name, dlen);
1.1 cgd 367: (void)closedir(dir);
368:
369: /* Truncate any file name. */
370: *bup = '\0';
371: }
372:
373: notfound:
374: /*
375: * If readdir set errno, use it, not any saved error; otherwise,
376: * didn't find the current directory in its parent directory, set
377: * errno to ENOENT.
378: */
379: if (!errno)
380: errno = save_errno ? save_errno : ENOENT;
381: /* FALLTHROUGH */
382: err:
383: if (ptsize)
384: free(pt);
385: free(up);
1.4 cgd 386: return (NULL);
1.1 cgd 387: }
1.16 sommerfe 388:
389: #else /* New getcwd */
390:
391: char *
392: getcwd(pt, size)
393: char *pt;
394: size_t size;
395: {
1.18 christos 396: size_t ptsize, bufsize;
397: int len;
1.16 sommerfe 398:
399: /*
400: * If no buffer specified by the user, allocate one as necessary.
401: * If a buffer is specified, the size has to be non-zero. The path
402: * is built from the end of the buffer backwards.
403: */
404: if (pt) {
405: ptsize = 0;
406: if (!size) {
407: errno = EINVAL;
408: return (NULL);
409: }
410: bufsize = size;
411: } else {
412: if ((pt = malloc(ptsize = 1024 - 4)) == NULL)
413: return (NULL);
414: bufsize = ptsize;
415: }
1.18 christos 416: for (;;) {
1.16 sommerfe 417: len = __getcwd(pt, bufsize);
418: if ((len < 0) && (size == 0) && (errno == ERANGE)) {
1.20 sommerfe 419: if (ptsize > (MAXPATHLEN*4))
420: return NULL;
1.16 sommerfe 421: if ((pt = realloc(pt, ptsize *= 2)) == NULL)
422: return NULL;
423: bufsize = ptsize;
424: continue;
425: }
1.18 christos 426: break;
427: }
1.16 sommerfe 428: if (len < 0)
429: return NULL;
430: else
431: return pt;
432: }
433:
434: #endif
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