1 /* $NetBSD: getcwd.c,v 1.53 2012/06/21 23:29:23 enami Exp $ */ 2 3 /* 4 * Copyright (c) 1989, 1991, 1993, 1995 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * Jan-Simon Pendry. 9 * 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. 18 * 3. Neither the name of the University nor the names of its contributors 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 35 #include <sys/cdefs.h> 36 #if defined(LIBC_SCCS) && !defined(lint) 37 #if 0 38 static char sccsid[] = "@(#)getcwd.c 8.5 (Berkeley) 2/7/95"; 39 #else 40 __RCSID("$NetBSD: getcwd.c,v 1.53 2012/06/21 23:29:23 enami Exp $"); 41 #endif 42 #endif /* LIBC_SCCS and not lint */ 43 44 #include "namespace.h" 45 #include <sys/param.h> 46 #include <sys/stat.h> 47 48 #include <assert.h> 49 #include <errno.h> 50 #include <stdlib.h> 51 #include <string.h> 52 #include <unistd.h> 53 #include <ssp/ssp.h> 54 55 #include "extern.h" 56 57 #ifdef __weak_alias 58 __weak_alias(getcwd,_getcwd) 59 __weak_alias(_sys_getcwd,_getcwd) 60 __weak_alias(realpath,_realpath) 61 #endif 62 63 /* 64 * char *realpath(const char *path, char *resolved); 65 * 66 * Find the real name of path, by removing all ".", ".." and symlink 67 * components. Returns (resolved) on success, or (NULL) on failure, 68 * in which case the path which caused trouble is left in (resolved). 69 */ 70 char * 71 realpath(const char * __restrict path, char * __restrict resolved) 72 { 73 struct stat sb; 74 int idx = 0, nlnk = 0; 75 const char *q; 76 char *p, wbuf[2][MAXPATHLEN], *fres; 77 size_t len; 78 ssize_t n; 79 80 /* POSIX sez we must test for this */ 81 if (path == NULL) { 82 errno = EINVAL; 83 return NULL; 84 } 85 86 if (resolved == NULL) { 87 fres = resolved = malloc(MAXPATHLEN); 88 if (resolved == NULL) 89 return NULL; 90 } else 91 fres = NULL; 92 93 94 /* 95 * Build real path one by one with paying an attention to ., 96 * .. and symbolic link. 97 */ 98 99 /* 100 * `p' is where we'll put a new component with prepending 101 * a delimiter. 102 */ 103 p = resolved; 104 105 if (*path == '\0') { 106 *p = '\0'; 107 errno = ENOENT; 108 goto out; 109 } 110 111 /* If relative path, start from current working directory. */ 112 if (*path != '/') { 113 /* check for resolved pointer to appease coverity */ 114 if (resolved && getcwd(resolved, MAXPATHLEN) == NULL) { 115 p[0] = '.'; 116 p[1] = '\0'; 117 goto out; 118 } 119 len = strlen(resolved); 120 if (len > 1) 121 p += len; 122 } 123 124 loop: 125 /* Skip any slash. */ 126 while (*path == '/') 127 path++; 128 129 if (*path == '\0') { 130 if (p == resolved) 131 *p++ = '/'; 132 *p = '\0'; 133 return resolved; 134 } 135 136 /* Find the end of this component. */ 137 q = path; 138 do 139 q++; 140 while (*q != '/' && *q != '\0'); 141 142 /* Test . or .. */ 143 if (path[0] == '.') { 144 if (q - path == 1) { 145 path = q; 146 goto loop; 147 } 148 if (path[1] == '.' && q - path == 2) { 149 /* Trim the last component. */ 150 if (p != resolved) 151 while (*--p != '/') 152 continue; 153 path = q; 154 goto loop; 155 } 156 } 157 158 /* Append this component. */ 159 if (p - resolved + 1 + q - path + 1 > MAXPATHLEN) { 160 errno = ENAMETOOLONG; 161 if (p == resolved) 162 *p++ = '/'; 163 *p = '\0'; 164 goto out; 165 } 166 p[0] = '/'; 167 memcpy(&p[1], path, 168 /* LINTED We know q > path. */ 169 q - path); 170 p[1 + q - path] = '\0'; 171 172 /* 173 * If this component is a symlink, toss it and prepend link 174 * target to unresolved path. 175 */ 176 if (lstat(resolved, &sb) == -1) 177 goto out; 178 179 if (S_ISLNK(sb.st_mode)) { 180 if (nlnk++ >= MAXSYMLINKS) { 181 errno = ELOOP; 182 goto out; 183 } 184 n = readlink(resolved, wbuf[idx], sizeof(wbuf[0]) - 1); 185 if (n < 0) 186 goto out; 187 if (n == 0) { 188 errno = ENOENT; 189 goto out; 190 } 191 192 /* Append unresolved path to link target and switch to it. */ 193 if (n + (len = strlen(q)) + 1 > sizeof(wbuf[0])) { 194 errno = ENAMETOOLONG; 195 goto out; 196 } 197 memcpy(&wbuf[idx][n], q, len + 1); 198 path = wbuf[idx]; 199 idx ^= 1; 200 201 /* If absolute symlink, start from root. */ 202 if (*path == '/') 203 p = resolved; 204 goto loop; 205 } 206 if (*q == '/' && !S_ISDIR(sb.st_mode)) { 207 errno = ENOTDIR; 208 goto out; 209 } 210 211 /* Advance both resolved and unresolved path. */ 212 p += 1 + q - path; 213 path = q; 214 goto loop; 215 out: 216 free(fres); 217 return NULL; 218 } 219 220 char * 221 __ssp_real(getcwd)(char *pt, size_t size) 222 { 223 char *npt; 224 225 /* 226 * If a buffer is specified, the size has to be non-zero. 227 */ 228 if (pt != NULL) { 229 if (size == 0) { 230 /* __getcwd(pt, 0) results ERANGE. */ 231 errno = EINVAL; 232 return (NULL); 233 } 234 if (__getcwd(pt, size) >= 0) 235 return (pt); 236 return (NULL); 237 } 238 239 /* 240 * If no buffer specified by the user, allocate one as necessary. 241 */ 242 size = 1024 >> 1; 243 do { 244 if ((npt = realloc(pt, size <<= 1)) == NULL) 245 break; 246 pt = npt; 247 if (__getcwd(pt, size) >= 0) 248 return (pt); 249 } while (size <= MAXPATHLEN * 4 && errno == ERANGE); 250 251 free(pt); 252 return (NULL); 253 } 254
Indexes created Mon Sep 29 15:09:53 GMT 2025