Annotation of src/lib/libc/gen/getcwd.c, Revision 1.45
1.45 ! christos 1: /* $NetBSD: getcwd.c,v 1.44 2007/06/03 17:39:26 christos 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
1.45 ! christos 40: __RCSID("$NetBSD: getcwd.c,v 1.44 2007/06/03 17:39:26 christos 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 != '/') {
1.43 christos 99: /* check for resolved pointer to appease coverity */
100: if (resolved && getcwd(resolved, MAXPATHLEN) == NULL) {
1.36 enami 101: p[0] = '.';
102: p[1] = 0;
103: return (NULL);
104: }
105: len = strlen(resolved);
106: if (len > 1)
107: p += len;
1.31 itojun 108: }
1.36 enami 109:
1.8 perry 110: loop:
1.36 enami 111: /* Skip any slash. */
112: while (*path == '/')
113: path++;
114:
115: if (*path == 0) {
116: if (p == resolved)
117: *p++ = '/';
118: *p = 0;
119: return (resolved);
120: }
121:
122: /* Find the end of this component. */
123: q = path;
124: do
125: q++;
126: while (*q != '/' && *q != 0);
127:
128: /* Test . or .. */
129: if (path[0] == '.') {
130: if (q - path == 1) {
131: path = q;
1.8 perry 132: goto loop;
133: }
1.36 enami 134: if (path[1] == '.' && q - path == 2) {
135: /* Trim the last component. */
136: if (p != resolved)
137: while (*--p != '/')
138: ;
139: path = q;
140: goto loop;
1.8 perry 141: }
142: }
143:
1.36 enami 144: /* Append this component. */
145: if (p - resolved + 1 + q - path + 1 > MAXPATHLEN) {
1.31 itojun 146: errno = ENAMETOOLONG;
1.36 enami 147: if (p == resolved)
148: *p++ = '/';
149: *p = 0;
150: return (NULL);
1.31 itojun 151: }
1.36 enami 152: p[0] = '/';
153: memcpy(&p[1], path,
154: /* LINTED We know q > path. */
155: q - path);
156: p[1 + q - path] = 0;
1.8 perry 157:
158: /*
1.36 enami 159: * If this component is a symlink, toss it and prepend link
160: * target to unresolved path.
161: */
162: if (lstat(resolved, &sb) == -1) {
163: return (NULL);
164: }
165: if (S_ISLNK(sb.st_mode)) {
166: if (nlnk++ >= MAXSYMLINKS) {
167: errno = ELOOP;
168: return (NULL);
169: }
170: n = readlink(resolved, wbuf[idx], sizeof(wbuf[0]) - 1);
171: if (n < 0)
172: return (NULL);
173: if (n == 0) {
174: errno = ENOENT;
175: return (NULL);
176: }
1.8 perry 177:
1.36 enami 178: /* Append unresolved path to link target and switch to it. */
179: if (n + (len = strlen(q)) + 1 > sizeof(wbuf[0])) {
1.8 perry 180: errno = ENAMETOOLONG;
1.36 enami 181: return (NULL);
1.31 itojun 182: }
1.36 enami 183: memcpy(&wbuf[idx][n], q, len + 1);
184: path = wbuf[idx];
185: idx ^= 1;
186:
187: /* If absolute symlink, start from root. */
188: if (*path == '/')
189: p = resolved;
190: goto loop;
1.8 perry 191: }
1.38 enami 192: if (*q == '/' && !S_ISDIR(sb.st_mode)) {
193: errno = ENOTDIR;
194: return (NULL);
195: }
1.8 perry 196:
1.36 enami 197: /* Advance both resolved and unresolved path. */
198: p += 1 + q - path;
199: path = q;
200: goto loop;
1.8 perry 201: }
202:
1.44 christos 203:
1.45 ! christos 204: #if defined(_FORTIFY_SOURCE) && !defined(__lint__)
1.44 christos 205: #undef getcwd
206: #define getcwd _getcwd
207: #endif
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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