Annotation of src/lib/libc/gen/getcwd.c, Revision 1.24.6.1
1.24.6.1! nathanw 1: /* $NetBSD$ */
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
1.24.6.1! nathanw 44: __RCSID("$NetBSD$");
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: */
1.24.6.1! nathanw 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) {
173: if (strlen(resolved) + strlen(wbuf) + rootd + 1 > MAXPATHLEN) {
174: errno = ENAMETOOLONG;
175: goto err1;
176: }
177: if (rootd == 0)
1.9 perry 178: (void)strcat(resolved, "/"); /* XXX: strcat is safe */
179: (void)strcat(resolved, wbuf); /* XXX: strcat is safe */
1.8 perry 180: }
181:
182: /* Go back to where we came from. */
183: if (fchdir(fd) < 0) {
184: serrno = errno;
185: goto err2;
186: }
187:
188: /* It's okay if the close fails, what's an fd more or less? */
189: (void)close(fd);
190: return (resolved);
191:
192: err1: serrno = errno;
193: (void)fchdir(fd);
194: err2: (void)close(fd);
195: errno = serrno;
196: return (NULL);
197: }
198:
1.16 sommerfe 199: #ifdef OLD_GETCWD
200:
1.12 lukem 201: char *
202: getcwd(pt, size)
1.8 perry 203: char *pt;
204: size_t size;
205: {
1.10 perry 206: struct dirent *dp;
207: DIR *dir;
208: dev_t dev;
209: ino_t ino;
210: int first;
211: char *bpt, *bup;
1.1 cgd 212: struct stat s;
213: dev_t root_dev;
214: ino_t root_ino;
215: size_t ptsize, upsize;
216: int save_errno;
217: char *ept, *eup, *up;
1.15 christos 218: size_t dlen;
1.1 cgd 219:
220: /*
221: * If no buffer specified by the user, allocate one as necessary.
222: * If a buffer is specified, the size has to be non-zero. The path
223: * is built from the end of the buffer backwards.
224: */
225: if (pt) {
226: ptsize = 0;
227: if (!size) {
228: errno = EINVAL;
1.4 cgd 229: return (NULL);
1.1 cgd 230: }
231: ept = pt + size;
232: } else {
1.4 cgd 233: if ((pt = malloc(ptsize = 1024 - 4)) == NULL)
234: return (NULL);
1.1 cgd 235: ept = pt + ptsize;
236: }
237: bpt = ept - 1;
238: *bpt = '\0';
239:
240: /*
241: * Allocate bytes (1024 - malloc space) for the string of "../"'s.
242: * Should always be enough (it's 340 levels). If it's not, allocate
1.8 perry 243: * as necessary. Special case the first stat, it's ".", not "..".
1.1 cgd 244: */
1.4 cgd 245: if ((up = malloc(upsize = 1024 - 4)) == NULL)
1.1 cgd 246: goto err;
247: eup = up + MAXPATHLEN;
248: bup = up;
249: up[0] = '.';
250: up[1] = '\0';
251:
252: /* Save root values, so know when to stop. */
253: if (stat("/", &s))
254: goto err;
255: root_dev = s.st_dev;
256: root_ino = s.st_ino;
257:
258: errno = 0; /* XXX readdir has no error return. */
259:
260: for (first = 1;; first = 0) {
261: /* Stat the current level. */
262: if (lstat(up, &s))
263: goto err;
264:
265: /* Save current node values. */
266: ino = s.st_ino;
267: dev = s.st_dev;
268:
269: /* Check for reaching root. */
270: if (root_dev == dev && root_ino == ino) {
271: *--bpt = '/';
272: /*
273: * It's unclear that it's a requirement to copy the
274: * path to the beginning of the buffer, but it's always
275: * been that way and stuff would probably break.
276: */
1.14 perry 277: memmove(pt, bpt, (size_t)(ept - bpt));
1.1 cgd 278: free(up);
1.4 cgd 279: return (pt);
1.1 cgd 280: }
281:
282: /*
283: * Build pointer to the parent directory, allocating memory
284: * as necessary. Max length is 3 for "../", the largest
285: * possible component name, plus a trailing NULL.
286: */
287: if (bup + 3 + MAXNAMLEN + 1 >= eup) {
1.4 cgd 288: if ((up = realloc(up, upsize *= 2)) == NULL)
1.1 cgd 289: goto err;
1.4 cgd 290: bup = up;
1.1 cgd 291: eup = up + upsize;
292: }
293: *bup++ = '.';
294: *bup++ = '.';
295: *bup = '\0';
296:
297: /* Open and stat parent directory. */
298: if (!(dir = opendir(up)) || fstat(dirfd(dir), &s))
299: goto err;
300:
301: /* Add trailing slash for next directory. */
302: *bup++ = '/';
303:
304: /*
305: * If it's a mount point, have to stat each element because
306: * the inode number in the directory is for the entry in the
307: * parent directory, not the inode number of the mounted file.
308: */
309: save_errno = 0;
310: if (s.st_dev == dev) {
311: for (;;) {
312: if (!(dp = readdir(dir)))
313: goto notfound;
1.15 christos 314: if (dp->d_fileno == ino) {
1.19 christos 315: #if defined(__SVR4) || defined(__svr4__) || defined(__linux__)
1.15 christos 316: dlen = strlen(dp->d_name);
317: #else
318: dlen = dp->d_namlen;
319: #endif
1.1 cgd 320: break;
1.15 christos 321: }
1.1 cgd 322: }
323: } else
324: for (;;) {
325: if (!(dp = readdir(dir)))
326: goto notfound;
327: if (ISDOT(dp))
328: continue;
1.19 christos 329: #if defined(__SVR4) || defined(__svr4__) || defined(__linux__)
1.15 christos 330: dlen = strlen(dp->d_name);
331: #else
332: dlen = dp->d_namlen;
333: #endif
334: memmove(bup, dp->d_name, dlen + 1);
1.1 cgd 335:
336: /* Save the first error for later. */
337: if (lstat(up, &s)) {
338: if (!save_errno)
339: save_errno = errno;
340: errno = 0;
341: continue;
342: }
343: if (s.st_dev == dev && s.st_ino == ino)
344: break;
345: }
346:
347: /*
348: * Check for length of the current name, preceding slash,
349: * leading slash.
350: */
1.15 christos 351: if (bpt - pt <= dlen + (first ? 1 : 2)) {
1.1 cgd 352: size_t len, off;
353:
354: if (!ptsize) {
355: errno = ERANGE;
356: goto err;
357: }
358: off = bpt - pt;
359: len = ept - bpt;
1.4 cgd 360: if ((pt = realloc(pt, ptsize *= 2)) == NULL)
1.1 cgd 361: goto err;
362: bpt = pt + off;
363: ept = pt + ptsize;
1.14 perry 364: memmove(ept - len, bpt, len);
1.1 cgd 365: bpt = ept - len;
366: }
367: if (!first)
368: *--bpt = '/';
1.15 christos 369: bpt -= dlen;
370: memmove(bpt, dp->d_name, dlen);
1.1 cgd 371: (void)closedir(dir);
372:
373: /* Truncate any file name. */
374: *bup = '\0';
375: }
376:
377: notfound:
378: /*
379: * If readdir set errno, use it, not any saved error; otherwise,
380: * didn't find the current directory in its parent directory, set
381: * errno to ENOENT.
382: */
383: if (!errno)
384: errno = save_errno ? save_errno : ENOENT;
385: /* FALLTHROUGH */
386: err:
387: if (ptsize)
388: free(pt);
389: free(up);
1.4 cgd 390: return (NULL);
1.1 cgd 391: }
1.16 sommerfe 392:
393: #else /* New getcwd */
394:
395: char *
396: getcwd(pt, size)
397: char *pt;
398: size_t size;
399: {
1.18 christos 400: size_t ptsize, bufsize;
401: int len;
1.16 sommerfe 402:
403: /*
404: * If no buffer specified by the user, allocate one as necessary.
405: * If a buffer is specified, the size has to be non-zero. The path
406: * is built from the end of the buffer backwards.
407: */
408: if (pt) {
409: ptsize = 0;
410: if (!size) {
411: errno = EINVAL;
412: return (NULL);
413: }
414: bufsize = size;
415: } else {
416: if ((pt = malloc(ptsize = 1024 - 4)) == NULL)
417: return (NULL);
418: bufsize = ptsize;
419: }
1.18 christos 420: for (;;) {
1.16 sommerfe 421: len = __getcwd(pt, bufsize);
422: if ((len < 0) && (size == 0) && (errno == ERANGE)) {
1.20 sommerfe 423: if (ptsize > (MAXPATHLEN*4))
424: return NULL;
1.16 sommerfe 425: if ((pt = realloc(pt, ptsize *= 2)) == NULL)
426: return NULL;
427: bufsize = ptsize;
428: continue;
429: }
1.18 christos 430: break;
431: }
1.16 sommerfe 432: if (len < 0)
433: return NULL;
434: else
435: return pt;
436: }
437:
438: #endif
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