Annotation of src/lib/libc/gen/getcwd.c, Revision 1.36
1.36 ! enami 1: /* $NetBSD: getcwd.c,v 1.35 2005/01/23 01:00:51 enami 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
1.36 ! enami 40: __RCSID("$NetBSD: getcwd.c,v 1.35 2005/01/23 01:00:51 enami 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;
1.36 ! enami 72: int idx = 0, n, nlnk = 0, serrno = errno;
! 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) {
! 162: /* Allow nonexistent component if this is the last one. */
! 163: if (*q == 0 && errno == ENOENT) {
! 164: errno = serrno;
! 165: return (resolved);
! 166: }
! 167: return (NULL);
! 168: }
! 169: if (S_ISLNK(sb.st_mode)) {
! 170: if (nlnk++ >= MAXSYMLINKS) {
! 171: errno = ELOOP;
! 172: return (NULL);
! 173: }
! 174: n = readlink(resolved, wbuf[idx], sizeof(wbuf[0]) - 1);
! 175: if (n < 0)
! 176: return (NULL);
! 177: if (n == 0) {
! 178: errno = ENOENT;
! 179: return (NULL);
! 180: }
1.8 perry 181:
1.36 ! enami 182: /* Append unresolved path to link target and switch to it. */
! 183: if (n + (len = strlen(q)) + 1 > sizeof(wbuf[0])) {
1.8 perry 184: errno = ENAMETOOLONG;
1.36 ! enami 185: return (NULL);
1.31 itojun 186: }
1.36 ! enami 187: memcpy(&wbuf[idx][n], q, len + 1);
! 188: path = wbuf[idx];
! 189: idx ^= 1;
! 190:
! 191: /* If absolute symlink, start from root. */
! 192: if (*path == '/')
! 193: p = resolved;
! 194: goto loop;
1.8 perry 195: }
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:
1.16 sommerfe 203: char *
1.35 enami 204: getcwd(char *pt, size_t size)
1.16 sommerfe 205: {
1.35 enami 206: char *npt;
207:
1.16 sommerfe 208: /*
1.35 enami 209: * If a buffer is specified, the size has to be non-zero.
1.16 sommerfe 210: */
1.35 enami 211: if (pt != NULL) {
212: if (size == 0) {
213: /* __getcwd(pt, 0) results ERANGE. */
1.16 sommerfe 214: errno = EINVAL;
215: return (NULL);
216: }
1.35 enami 217: if (__getcwd(pt, size) >= 0)
218: return (pt);
219: return (NULL);
1.16 sommerfe 220: }
1.35 enami 221:
222: /*
223: * If no buffer specified by the user, allocate one as necessary.
224: */
225: size = 1024 >> 1;
226: do {
227: if ((npt = realloc(pt, size <<= 1)) == NULL)
228: break;
229: pt = npt;
230: if (__getcwd(pt, size) >= 0)
231: return (pt);
232: } while (size <= MAXPATHLEN * 4 && errno == ERANGE);
233:
234: free(pt);
235: return (NULL);
1.16 sommerfe 236: }
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