Annotation of src/lib/libc/gen/getcwd.c, Revision 1.41
1.41 ! elad 1: /* $NetBSD: getcwd.c,v 1.40 2005/08/13 21:16:58 elad 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.
1.32 agc 18: * 3. Neither the name of the University nor the names of its contributors
1.1 cgd 19: * may be used to endorse or promote products derived from this software
20: * without specific prior written permission.
21: *
22: * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25: * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32: * SUCH DAMAGE.
33: */
34:
1.6 christos 35: #include <sys/cdefs.h>
1.1 cgd 36: #if defined(LIBC_SCCS) && !defined(lint)
1.4 cgd 37: #if 0
1.8 perry 38: static char sccsid[] = "@(#)getcwd.c 8.5 (Berkeley) 2/7/95";
1.4 cgd 39: #else
1.41 ! elad 40: __RCSID("$NetBSD: getcwd.c,v 1.40 2005/08/13 21:16:58 elad Exp $");
1.4 cgd 41: #endif
1.1 cgd 42: #endif /* LIBC_SCCS and not lint */
43:
1.7 jtc 44: #include "namespace.h"
1.1 cgd 45: #include <sys/param.h>
46: #include <sys/stat.h>
1.8 perry 47:
1.22 lukem 48: #include <assert.h>
1.1 cgd 49: #include <errno.h>
50: #include <stdlib.h>
51: #include <string.h>
52: #include <unistd.h>
1.17 sommerfe 53:
54: #include "extern.h"
1.7 jtc 55:
56: #ifdef __weak_alias
1.24 mycroft 57: __weak_alias(getcwd,_getcwd)
58: __weak_alias(realpath,_realpath)
1.7 jtc 59: #endif
1.1 cgd 60:
1.8 perry 61: /*
1.36 enami 62: * char *realpath(const char *path, char resolved[MAXPATHLEN]);
1.8 perry 63: *
64: * Find the real name of path, by removing all ".", ".." and symlink
65: * components. Returns (resolved) on success, or (NULL) on failure,
66: * in which case the path which caused trouble is left in (resolved).
67: */
68: char *
1.36 enami 69: realpath(const char *path, char *resolved)
1.8 perry 70: {
71: struct stat sb;
1.40 elad 72: int idx = 0, n, nlnk = 0;
1.36 enami 73: const char *q;
74: char *p, wbuf[2][MAXPATHLEN];
75: size_t len;
1.22 lukem 76:
77: _DIAGASSERT(path != NULL);
78: _DIAGASSERT(resolved != NULL);
1.8 perry 79:
1.36 enami 80: /*
81: * Build real path one by one with paying an attention to .,
82: * .. and symbolic link.
83: */
84:
85: /*
86: * `p' is where we'll put a new component with prepending
87: * a delimiter.
88: */
89: p = resolved;
90:
91: if (*path == 0) {
92: *p = 0;
93: errno = ENOENT;
1.8 perry 94: return (NULL);
95: }
96:
1.36 enami 97: /* If relative path, start from current working directory. */
98: if (*path != '/') {
99: if (getcwd(resolved, MAXPATHLEN) == NULL) {
100: p[0] = '.';
101: p[1] = 0;
102: return (NULL);
103: }
104: len = strlen(resolved);
105: if (len > 1)
106: p += len;
1.31 itojun 107: }
1.36 enami 108:
1.8 perry 109: loop:
1.36 enami 110: /* Skip any slash. */
111: while (*path == '/')
112: path++;
113:
114: if (*path == 0) {
115: if (p == resolved)
116: *p++ = '/';
117: *p = 0;
118: return (resolved);
119: }
120:
121: /* Find the end of this component. */
122: q = path;
123: do
124: q++;
125: while (*q != '/' && *q != 0);
126:
127: /* Test . or .. */
128: if (path[0] == '.') {
129: if (q - path == 1) {
130: path = q;
1.8 perry 131: goto loop;
132: }
1.36 enami 133: if (path[1] == '.' && q - path == 2) {
134: /* Trim the last component. */
135: if (p != resolved)
136: while (*--p != '/')
137: ;
138: path = q;
139: goto loop;
1.8 perry 140: }
141: }
142:
1.36 enami 143: /* Append this component. */
144: if (p - resolved + 1 + q - path + 1 > MAXPATHLEN) {
1.31 itojun 145: errno = ENAMETOOLONG;
1.36 enami 146: if (p == resolved)
147: *p++ = '/';
148: *p = 0;
149: return (NULL);
1.31 itojun 150: }
1.36 enami 151: p[0] = '/';
152: memcpy(&p[1], path,
153: /* LINTED We know q > path. */
154: q - path);
155: p[1 + q - path] = 0;
1.8 perry 156:
157: /*
1.36 enami 158: * If this component is a symlink, toss it and prepend link
159: * target to unresolved path.
160: */
161: if (lstat(resolved, &sb) == -1) {
1.41 ! elad 162: /* Allow nonexistent component if this is the last one. */
! 163: while (*q == '/')
! 164: q++;
! 165:
! 166: if (*q == 0 && errno == ENOENT)
! 167: return (resolved);
! 168:
1.36 enami 169: return (NULL);
170: }
171: if (S_ISLNK(sb.st_mode)) {
172: if (nlnk++ >= MAXSYMLINKS) {
173: errno = ELOOP;
174: return (NULL);
175: }
176: n = readlink(resolved, wbuf[idx], sizeof(wbuf[0]) - 1);
177: if (n < 0)
178: return (NULL);
179: if (n == 0) {
180: errno = ENOENT;
181: return (NULL);
182: }
1.8 perry 183:
1.36 enami 184: /* Append unresolved path to link target and switch to it. */
185: if (n + (len = strlen(q)) + 1 > sizeof(wbuf[0])) {
1.8 perry 186: errno = ENAMETOOLONG;
1.36 enami 187: return (NULL);
1.31 itojun 188: }
1.36 enami 189: memcpy(&wbuf[idx][n], q, len + 1);
190: path = wbuf[idx];
191: idx ^= 1;
192:
193: /* If absolute symlink, start from root. */
194: if (*path == '/')
195: p = resolved;
196: goto loop;
1.8 perry 197: }
1.38 enami 198: if (*q == '/' && !S_ISDIR(sb.st_mode)) {
199: errno = ENOTDIR;
200: return (NULL);
201: }
1.8 perry 202:
1.36 enami 203: /* Advance both resolved and unresolved path. */
204: p += 1 + q - path;
205: path = q;
206: goto loop;
1.8 perry 207: }
208:
1.16 sommerfe 209: char *
1.35 enami 210: getcwd(char *pt, size_t size)
1.16 sommerfe 211: {
1.35 enami 212: char *npt;
213:
1.16 sommerfe 214: /*
1.35 enami 215: * If a buffer is specified, the size has to be non-zero.
1.16 sommerfe 216: */
1.35 enami 217: if (pt != NULL) {
218: if (size == 0) {
219: /* __getcwd(pt, 0) results ERANGE. */
1.16 sommerfe 220: errno = EINVAL;
221: return (NULL);
222: }
1.35 enami 223: if (__getcwd(pt, size) >= 0)
224: return (pt);
225: return (NULL);
1.16 sommerfe 226: }
1.35 enami 227:
228: /*
229: * If no buffer specified by the user, allocate one as necessary.
230: */
231: size = 1024 >> 1;
232: do {
233: if ((npt = realloc(pt, size <<= 1)) == NULL)
234: break;
235: pt = npt;
236: if (__getcwd(pt, size) >= 0)
237: return (pt);
238: } while (size <= MAXPATHLEN * 4 && errno == ERANGE);
239:
240: free(pt);
241: return (NULL);
1.16 sommerfe 242: }
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