Annotation of src/lib/libc/gen/getcwd.c, Revision 1.48
1.48 ! christos 1: /* $NetBSD: getcwd.c,v 1.47 2011/01/20 02:57:00 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
1.48 ! christos 40: __RCSID("$NetBSD: getcwd.c,v 1.47 2011/01/20 02:57:00 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
1.47 christos 57: __weak_alias(getcwd,_sys_getcwd)
58: __weak_alias(_getcwd,_sys_getcwd)
1.24 mycroft 59: __weak_alias(realpath,_realpath)
1.47 christos 60:
61: #undef getcwd
62: #define getcwd _sys_getcwd
1.48 ! christos 63: #if !defined(_FORTIFY_SOURCE)
! 64: char *_sys_getcwd(char *, size_t);
1.47 christos 65: #endif
66:
1.7 jtc 67: #endif
1.1 cgd 68:
1.8 perry 69: /*
1.36 enami 70: * char *realpath(const char *path, char resolved[MAXPATHLEN]);
1.8 perry 71: *
72: * Find the real name of path, by removing all ".", ".." and symlink
73: * components. Returns (resolved) on success, or (NULL) on failure,
74: * in which case the path which caused trouble is left in (resolved).
75: */
76: char *
1.36 enami 77: realpath(const char *path, char *resolved)
1.8 perry 78: {
79: struct stat sb;
1.40 elad 80: int idx = 0, n, nlnk = 0;
1.36 enami 81: const char *q;
82: char *p, wbuf[2][MAXPATHLEN];
83: size_t len;
1.22 lukem 84:
85: _DIAGASSERT(resolved != NULL);
1.8 perry 86:
1.46 dholland 87: /* POSIX sez we must test for this */
88: if (path == NULL) {
89: errno = EINVAL;
90: return NULL;
91: }
92:
1.36 enami 93: /*
94: * Build real path one by one with paying an attention to .,
95: * .. and symbolic link.
96: */
97:
98: /*
99: * `p' is where we'll put a new component with prepending
100: * a delimiter.
101: */
102: p = resolved;
103:
104: if (*path == 0) {
105: *p = 0;
106: errno = ENOENT;
1.8 perry 107: return (NULL);
108: }
109:
1.36 enami 110: /* If relative path, start from current working directory. */
111: if (*path != '/') {
1.43 christos 112: /* check for resolved pointer to appease coverity */
113: if (resolved && getcwd(resolved, MAXPATHLEN) == NULL) {
1.36 enami 114: p[0] = '.';
115: p[1] = 0;
116: return (NULL);
117: }
118: len = strlen(resolved);
119: if (len > 1)
120: p += len;
1.31 itojun 121: }
1.36 enami 122:
1.8 perry 123: loop:
1.36 enami 124: /* Skip any slash. */
125: while (*path == '/')
126: path++;
127:
128: if (*path == 0) {
129: if (p == resolved)
130: *p++ = '/';
131: *p = 0;
132: return (resolved);
133: }
134:
135: /* Find the end of this component. */
136: q = path;
137: do
138: q++;
139: while (*q != '/' && *q != 0);
140:
141: /* Test . or .. */
142: if (path[0] == '.') {
143: if (q - path == 1) {
144: path = q;
1.8 perry 145: goto loop;
146: }
1.36 enami 147: if (path[1] == '.' && q - path == 2) {
148: /* Trim the last component. */
149: if (p != resolved)
150: while (*--p != '/')
151: ;
152: path = q;
153: goto loop;
1.8 perry 154: }
155: }
156:
1.36 enami 157: /* Append this component. */
158: if (p - resolved + 1 + q - path + 1 > MAXPATHLEN) {
1.31 itojun 159: errno = ENAMETOOLONG;
1.36 enami 160: if (p == resolved)
161: *p++ = '/';
162: *p = 0;
163: return (NULL);
1.31 itojun 164: }
1.36 enami 165: p[0] = '/';
166: memcpy(&p[1], path,
167: /* LINTED We know q > path. */
168: q - path);
169: p[1 + q - path] = 0;
1.8 perry 170:
171: /*
1.36 enami 172: * If this component is a symlink, toss it and prepend link
173: * target to unresolved path.
174: */
175: if (lstat(resolved, &sb) == -1) {
176: return (NULL);
177: }
178: if (S_ISLNK(sb.st_mode)) {
179: if (nlnk++ >= MAXSYMLINKS) {
180: errno = ELOOP;
181: return (NULL);
182: }
183: n = readlink(resolved, wbuf[idx], sizeof(wbuf[0]) - 1);
184: if (n < 0)
185: return (NULL);
186: if (n == 0) {
187: errno = ENOENT;
188: return (NULL);
189: }
1.8 perry 190:
1.36 enami 191: /* Append unresolved path to link target and switch to it. */
192: if (n + (len = strlen(q)) + 1 > sizeof(wbuf[0])) {
1.8 perry 193: errno = ENAMETOOLONG;
1.36 enami 194: return (NULL);
1.31 itojun 195: }
1.36 enami 196: memcpy(&wbuf[idx][n], q, len + 1);
197: path = wbuf[idx];
198: idx ^= 1;
199:
200: /* If absolute symlink, start from root. */
201: if (*path == '/')
202: p = resolved;
203: goto loop;
1.8 perry 204: }
1.38 enami 205: if (*q == '/' && !S_ISDIR(sb.st_mode)) {
206: errno = ENOTDIR;
207: return (NULL);
208: }
1.8 perry 209:
1.36 enami 210: /* Advance both resolved and unresolved path. */
211: p += 1 + q - path;
212: path = q;
213: goto loop;
1.8 perry 214: }
215:
1.16 sommerfe 216: char *
1.35 enami 217: getcwd(char *pt, size_t size)
1.16 sommerfe 218: {
1.35 enami 219: char *npt;
220:
1.16 sommerfe 221: /*
1.35 enami 222: * If a buffer is specified, the size has to be non-zero.
1.16 sommerfe 223: */
1.35 enami 224: if (pt != NULL) {
225: if (size == 0) {
226: /* __getcwd(pt, 0) results ERANGE. */
1.16 sommerfe 227: errno = EINVAL;
228: return (NULL);
229: }
1.35 enami 230: if (__getcwd(pt, size) >= 0)
231: return (pt);
232: return (NULL);
1.16 sommerfe 233: }
1.35 enami 234:
235: /*
236: * If no buffer specified by the user, allocate one as necessary.
237: */
238: size = 1024 >> 1;
239: do {
240: if ((npt = realloc(pt, size <<= 1)) == NULL)
241: break;
242: pt = npt;
243: if (__getcwd(pt, size) >= 0)
244: return (pt);
245: } while (size <= MAXPATHLEN * 4 && errno == ERANGE);
246:
247: free(pt);
248: return (NULL);
1.16 sommerfe 249: }
CVSweb <webmaster@jp.NetBSD.org>