Annotation of src/lib/libc/gen/getcwd.c, Revision 1.46.2.2
1.46.2.2! bouyer 1: /* $NetBSD: getcwd.c,v 1.49 2011/02/16 20:20:25 tron 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
1.46.2.2! bouyer 40: __RCSID("$NetBSD: getcwd.c,v 1.49 2011/02/16 20:20:25 tron 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
1.46.2.1 bouyer 57: __weak_alias(getcwd,_sys_getcwd)
58: __weak_alias(_getcwd,_sys_getcwd)
1.24 mycroft 59: __weak_alias(realpath,_realpath)
1.46.2.1 bouyer 60:
1.46.2.2! bouyer 61: #if !defined(lint)
1.46.2.1 bouyer 62: #undef getcwd
63: #define getcwd _sys_getcwd
1.46.2.2! bouyer 64: #if !defined(_FORTIFY_SOURCE)
! 65: char *_sys_getcwd(char *, size_t);
1.46.2.1 bouyer 66: #endif
67:
1.7 jtc 68: #endif
1.46.2.2! bouyer 69: #endif
1.1 cgd 70:
1.8 perry 71: /*
1.36 enami 72: * char *realpath(const char *path, char resolved[MAXPATHLEN]);
1.8 perry 73: *
74: * Find the real name of path, by removing all ".", ".." and symlink
75: * components. Returns (resolved) on success, or (NULL) on failure,
76: * in which case the path which caused trouble is left in (resolved).
77: */
78: char *
1.36 enami 79: realpath(const char *path, char *resolved)
1.8 perry 80: {
81: struct stat sb;
1.40 elad 82: int idx = 0, n, nlnk = 0;
1.36 enami 83: const char *q;
84: char *p, wbuf[2][MAXPATHLEN];
85: size_t len;
1.22 lukem 86:
87: _DIAGASSERT(resolved != NULL);
1.8 perry 88:
1.46 dholland 89: /* POSIX sez we must test for this */
90: if (path == NULL) {
91: errno = EINVAL;
92: return NULL;
93: }
94:
1.36 enami 95: /*
96: * Build real path one by one with paying an attention to .,
97: * .. and symbolic link.
98: */
99:
100: /*
101: * `p' is where we'll put a new component with prepending
102: * a delimiter.
103: */
104: p = resolved;
105:
106: if (*path == 0) {
107: *p = 0;
108: errno = ENOENT;
1.8 perry 109: return (NULL);
110: }
111:
1.36 enami 112: /* If relative path, start from current working directory. */
113: if (*path != '/') {
1.43 christos 114: /* check for resolved pointer to appease coverity */
115: if (resolved && getcwd(resolved, MAXPATHLEN) == NULL) {
1.36 enami 116: p[0] = '.';
117: p[1] = 0;
118: return (NULL);
119: }
120: len = strlen(resolved);
121: if (len > 1)
122: p += len;
1.31 itojun 123: }
1.36 enami 124:
1.8 perry 125: loop:
1.36 enami 126: /* Skip any slash. */
127: while (*path == '/')
128: path++;
129:
130: if (*path == 0) {
131: if (p == resolved)
132: *p++ = '/';
133: *p = 0;
134: return (resolved);
135: }
136:
137: /* Find the end of this component. */
138: q = path;
139: do
140: q++;
141: while (*q != '/' && *q != 0);
142:
143: /* Test . or .. */
144: if (path[0] == '.') {
145: if (q - path == 1) {
146: path = q;
1.8 perry 147: goto loop;
148: }
1.36 enami 149: if (path[1] == '.' && q - path == 2) {
150: /* Trim the last component. */
151: if (p != resolved)
152: while (*--p != '/')
153: ;
154: path = q;
155: goto loop;
1.8 perry 156: }
157: }
158:
1.36 enami 159: /* Append this component. */
160: if (p - resolved + 1 + q - path + 1 > MAXPATHLEN) {
1.31 itojun 161: errno = ENAMETOOLONG;
1.36 enami 162: if (p == resolved)
163: *p++ = '/';
164: *p = 0;
165: return (NULL);
1.31 itojun 166: }
1.36 enami 167: p[0] = '/';
168: memcpy(&p[1], path,
169: /* LINTED We know q > path. */
170: q - path);
171: p[1 + q - path] = 0;
1.8 perry 172:
173: /*
1.36 enami 174: * If this component is a symlink, toss it and prepend link
175: * target to unresolved path.
176: */
177: if (lstat(resolved, &sb) == -1) {
178: return (NULL);
179: }
180: if (S_ISLNK(sb.st_mode)) {
181: if (nlnk++ >= MAXSYMLINKS) {
182: errno = ELOOP;
183: return (NULL);
184: }
185: n = readlink(resolved, wbuf[idx], sizeof(wbuf[0]) - 1);
186: if (n < 0)
187: return (NULL);
188: if (n == 0) {
189: errno = ENOENT;
190: return (NULL);
191: }
1.8 perry 192:
1.36 enami 193: /* Append unresolved path to link target and switch to it. */
194: if (n + (len = strlen(q)) + 1 > sizeof(wbuf[0])) {
1.8 perry 195: errno = ENAMETOOLONG;
1.36 enami 196: return (NULL);
1.31 itojun 197: }
1.36 enami 198: memcpy(&wbuf[idx][n], q, len + 1);
199: path = wbuf[idx];
200: idx ^= 1;
201:
202: /* If absolute symlink, start from root. */
203: if (*path == '/')
204: p = resolved;
205: goto loop;
1.8 perry 206: }
1.38 enami 207: if (*q == '/' && !S_ISDIR(sb.st_mode)) {
208: errno = ENOTDIR;
209: return (NULL);
210: }
1.8 perry 211:
1.36 enami 212: /* Advance both resolved and unresolved path. */
213: p += 1 + q - path;
214: path = q;
215: goto loop;
1.8 perry 216: }
217:
1.16 sommerfe 218: char *
1.35 enami 219: getcwd(char *pt, size_t size)
1.16 sommerfe 220: {
1.35 enami 221: char *npt;
222:
1.16 sommerfe 223: /*
1.35 enami 224: * If a buffer is specified, the size has to be non-zero.
1.16 sommerfe 225: */
1.35 enami 226: if (pt != NULL) {
227: if (size == 0) {
228: /* __getcwd(pt, 0) results ERANGE. */
1.16 sommerfe 229: errno = EINVAL;
230: return (NULL);
231: }
1.35 enami 232: if (__getcwd(pt, size) >= 0)
233: return (pt);
234: return (NULL);
1.16 sommerfe 235: }
1.35 enami 236:
237: /*
238: * If no buffer specified by the user, allocate one as necessary.
239: */
240: size = 1024 >> 1;
241: do {
242: if ((npt = realloc(pt, size <<= 1)) == NULL)
243: break;
244: pt = npt;
245: if (__getcwd(pt, size) >= 0)
246: return (pt);
247: } while (size <= MAXPATHLEN * 4 && errno == ERANGE);
248:
249: free(pt);
250: return (NULL);
1.16 sommerfe 251: }
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