1 /* $NetBSD: old_getcwd.c,v 1.2 2002/02/21 07:38:20 itojun 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. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the University of 21 * California, Berkeley and its contributors. 22 * 4. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 */ 38 39 /* 40 * This file copied from NetBSD's src/lib/libc/gen/getcwd.c 1.15, and edited 41 * to remove namespace stuff and the unused realpath function. 42 */ 43 44 45 #include <sys/cdefs.h> 46 #if defined(LIBC_SCCS) && !defined(lint) 47 #if 0 48 static char sccsid[] = "@(#)getcwd.c 8.5 (Berkeley) 2/7/95"; 49 #else 50 __RCSID("$NetBSD: old_getcwd.c,v 1.2 2002/02/21 07:38:20 itojun Exp $"); 51 #endif 52 #endif /* LIBC_SCCS and not lint */ 53 54 #include <sys/param.h> 55 #include <sys/stat.h> 56 57 #include <dirent.h> 58 #include <errno.h> 59 #include <fcntl.h> 60 #include <stdio.h> 61 #include <stdlib.h> 62 #include <string.h> 63 #include <unistd.h> 64 65 #include "getcwd.h" 66 67 #define ISDOT(dp) \ 68 (dp->d_name[0] == '.' && (dp->d_name[1] == '\0' || \ 69 (dp->d_name[1] == '.' && dp->d_name[2] == '\0'))) 70 71 72 #if defined(__SVR4) || defined(__svr4__) 73 #define d_fileno d_ino 74 #endif 75 76 char * 77 old_getcwd(pt, size) 78 char *pt; 79 size_t size; 80 { 81 struct dirent *dp; 82 DIR *dir; 83 dev_t dev; 84 ino_t ino; 85 int first; 86 char *bpt, *bup; 87 struct stat s; 88 dev_t root_dev; 89 ino_t root_ino; 90 size_t ptsize, upsize; 91 int save_errno; 92 char *ept, *eup, *up; 93 size_t dlen; 94 95 /* 96 * If no buffer specified by the user, allocate one as necessary. 97 * If a buffer is specified, the size has to be non-zero. The path 98 * is built from the end of the buffer backwards. 99 */ 100 if (pt) { 101 ptsize = 0; 102 if (!size) { 103 errno = EINVAL; 104 return (NULL); 105 } 106 ept = pt + size; 107 } else { 108 if ((pt = malloc(ptsize = 1024 - 4)) == NULL) 109 return (NULL); 110 ept = pt + ptsize; 111 } 112 bpt = ept - 1; 113 *bpt = '\0'; 114 115 /* 116 * Allocate bytes (1024 - malloc space) for the string of "../"'s. 117 * Should always be enough (it's 340 levels). If it's not, allocate 118 * as necessary. Special case the first stat, it's ".", not "..". 119 */ 120 if ((up = malloc(upsize = 1024 - 4)) == NULL) 121 goto err; 122 eup = up + MAXPATHLEN; 123 bup = up; 124 up[0] = '.'; 125 up[1] = '\0'; 126 127 /* Save root values, so know when to stop. */ 128 if (stat("/", &s)) 129 goto err; 130 root_dev = s.st_dev; 131 root_ino = s.st_ino; 132 133 errno = 0; /* XXX readdir has no error return. */ 134 135 for (first = 1;; first = 0) { 136 /* Stat the current level. */ 137 if (lstat(up, &s)) 138 goto err; 139 140 /* Save current node values. */ 141 ino = s.st_ino; 142 dev = s.st_dev; 143 144 /* Check for reaching root. */ 145 if (root_dev == dev && root_ino == ino) { 146 *--bpt = '/'; 147 /* 148 * It's unclear that it's a requirement to copy the 149 * path to the beginning of the buffer, but it's always 150 * been that way and stuff would probably break. 151 */ 152 memmove(pt, bpt, (size_t)(ept - bpt)); 153 free(up); 154 return (pt); 155 } 156 157 /* 158 * Build pointer to the parent directory, allocating memory 159 * as necessary. Max length is 3 for "../", the largest 160 * possible component name, plus a trailing NULL. 161 */ 162 if (bup + 3 + MAXNAMLEN + 1 >= eup) { 163 if ((up = realloc(up, upsize *= 2)) == NULL) 164 goto err; 165 bup = up; 166 eup = up + upsize; 167 } 168 *bup++ = '.'; 169 *bup++ = '.'; 170 *bup = '\0'; 171 172 /* Open and stat parent directory. */ 173 if (!(dir = opendir(up)) || fstat(dirfd(dir), &s)) 174 goto err; 175 176 /* Add trailing slash for next directory. */ 177 *bup++ = '/'; 178 179 /* 180 * If it's a mount point, have to stat each element because 181 * the inode number in the directory is for the entry in the 182 * parent directory, not the inode number of the mounted file. 183 */ 184 save_errno = 0; 185 if (s.st_dev == dev) { 186 for (;;) { 187 if (!(dp = readdir(dir))) 188 goto notfound; 189 if (dp->d_fileno == ino) { 190 #if defined(__SVR4) || defined(__svr4__) 191 dlen = strlen(dp->d_name); 192 #else 193 dlen = dp->d_namlen; 194 #endif 195 break; 196 } 197 } 198 } else 199 for (;;) { 200 if (!(dp = readdir(dir))) 201 goto notfound; 202 if (ISDOT(dp)) 203 continue; 204 #if defined(__SVR4) || defined(__svr4__) 205 dlen = strlen(dp->d_name); 206 #else 207 dlen = dp->d_namlen; 208 #endif 209 memmove(bup, dp->d_name, dlen + 1); 210 211 /* Save the first error for later. */ 212 if (lstat(up, &s)) { 213 if (!save_errno) 214 save_errno = errno; 215 errno = 0; 216 continue; 217 } 218 if (s.st_dev == dev && s.st_ino == ino) 219 break; 220 } 221 222 /* 223 * Check for length of the current name, preceding slash, 224 * leading slash. 225 */ 226 if (bpt - pt <= dlen + (first ? 1 : 2)) { 227 size_t len, off; 228 229 if (!ptsize) { 230 errno = ERANGE; 231 goto err; 232 } 233 off = bpt - pt; 234 len = ept - bpt; 235 if ((pt = realloc(pt, ptsize *= 2)) == NULL) 236 goto err; 237 bpt = pt + off; 238 ept = pt + ptsize; 239 memmove(ept - len, bpt, len); 240 bpt = ept - len; 241 } 242 if (!first) 243 *--bpt = '/'; 244 bpt -= dlen; 245 memmove(bpt, dp->d_name, dlen); 246 (void)closedir(dir); 247 248 /* Truncate any file name. */ 249 *bup = '\0'; 250 } 251 252 notfound: 253 /* 254 * If readdir set errno, use it, not any saved error; otherwise, 255 * didn't find the current directory in its parent directory, set 256 * errno to ENOENT. 257 */ 258 if (!errno) 259 errno = save_errno ? save_errno : ENOENT; 260 /* FALLTHROUGH */ 261 err: 262 if (ptsize) 263 free(pt); 264 free(up); 265 return (NULL); 266 } 267