1 /* 2 * Copyright (c) 1989, 1991, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 */ 26 27 #include "includes.h" 28 29 #if !defined(HAVE_GETCWD) 30 31 #if defined(LIBC_SCCS) && !defined(lint) 32 static char rcsid[] = "$OpenBSD: getcwd.c,v 1.6 2000/07/19 15:25:13 deraadt Exp $"; 33 #endif /* LIBC_SCCS and not lint */ 34 35 #include <sys/param.h> 36 #include <sys/stat.h> 37 #include <errno.h> 38 #include <dirent.h> 39 #include <sys/dir.h> 40 #include <stdio.h> 41 #include <stdlib.h> 42 #include <string.h> 43 #include "includes.h" 44 45 #define ISDOT(dp) \ 46 (dp->d_name[0] == '.' && (dp->d_name[1] == '\0' || \ 47 (dp->d_name[1] == '.' && dp->d_name[2] == '\0'))) 48 49 char * 50 getcwd(char *pt,size_t size) 51 { 52 register struct dirent *dp; 53 register DIR *dir = NULL; 54 register dev_t dev; 55 register ino_t ino; 56 register int first; 57 register char *bpt, *bup; 58 struct stat s; 59 dev_t root_dev; 60 ino_t root_ino; 61 size_t ptsize, upsize; 62 int save_errno; 63 char *ept, *eup, *up; 64 65 /* 66 * If no buffer specified by the user, allocate one as necessary. 67 * If a buffer is specified, the size has to be non-zero. The path 68 * is built from the end of the buffer backwards. 69 */ 70 if (pt) { 71 ptsize = 0; 72 if (!size) { 73 errno = EINVAL; 74 return (NULL); 75 } 76 ept = pt + size; 77 } else { 78 if ((pt = malloc(ptsize = 1024 - 4)) == NULL) 79 return (NULL); 80 ept = pt + ptsize; 81 } 82 bpt = ept - 1; 83 *bpt = '\0'; 84 85 /* 86 * Allocate bytes (1024 - malloc space) for the string of "../"'s. 87 * Should always be enough (it's 340 levels). If it's not, allocate 88 * as necessary. Special * case the first stat, it's ".", not "..". 89 */ 90 if ((up = malloc(upsize = 1024 - 4)) == NULL) 91 goto err; 92 eup = up + MAXPATHLEN; 93 bup = up; 94 up[0] = '.'; 95 up[1] = '\0'; 96 97 /* Save root values, so know when to stop. */ 98 if (stat("/", &s)) 99 goto err; 100 root_dev = s.st_dev; 101 root_ino = s.st_ino; 102 103 errno = 0; /* XXX readdir has no error return. */ 104 105 for (first = 1;; first = 0) { 106 /* Stat the current level. */ 107 if (lstat(up, &s)) 108 goto err; 109 110 /* Save current node values. */ 111 ino = s.st_ino; 112 dev = s.st_dev; 113 114 /* Check for reaching root. */ 115 if (root_dev == dev && root_ino == ino) { 116 *--bpt = '/'; 117 /* 118 * It's unclear that it's a requirement to copy the 119 * path to the beginning of the buffer, but it's always 120 * been that way and stuff would probably break. 121 */ 122 memmove(pt, bpt, ept - bpt); 123 free(up); 124 return (pt); 125 } 126 127 /* 128 * Build pointer to the parent directory, allocating memory 129 * as necessary. Max length is 3 for "../", the largest 130 * possible component name, plus a trailing NULL. 131 */ 132 if (bup + 3 + MAXNAMLEN + 1 >= eup) { 133 char *nup; 134 135 if ((nup = realloc(up, upsize *= 2)) == NULL) 136 goto err; 137 up = nup; 138 bup = up; 139 eup = up + upsize; 140 } 141 *bup++ = '.'; 142 *bup++ = '.'; 143 *bup = '\0'; 144 145 /* Open and stat parent directory. 146 * RACE?? - replaced fstat(dirfd(dir), &s) w/ lstat(up,&s) 147 */ 148 if (!(dir = opendir(up)) || lstat(up,&s)) 149 goto err; 150 151 /* Add trailing slash for next directory. */ 152 *bup++ = '/'; 153 154 /* 155 * If it's a mount point, have to stat each element because 156 * the inode number in the directory is for the entry in the 157 * parent directory, not the inode number of the mounted file. 158 */ 159 save_errno = 0; 160 if (s.st_dev == dev) { 161 for (;;) { 162 if (!(dp = readdir(dir))) 163 goto notfound; 164 if (dp->d_fileno == ino) 165 break; 166 } 167 } else 168 for (;;) { 169 if (!(dp = readdir(dir))) 170 goto notfound; 171 if (ISDOT(dp)) 172 continue; 173 memmove(bup, dp->d_name, dp->d_namlen + 1); 174 175 /* Save the first error for later. */ 176 if (lstat(up, &s)) { 177 if (!save_errno) 178 save_errno = errno; 179 errno = 0; 180 continue; 181 } 182 if (s.st_dev == dev && s.st_ino == ino) 183 break; 184 } 185 186 /* 187 * Check for length of the current name, preceding slash, 188 * leading slash. 189 */ 190 if (bpt - pt < dp->d_namlen + (first ? 1 : 2)) { 191 size_t len, off; 192 char *npt; 193 194 if (!ptsize) { 195 errno = ERANGE; 196 goto err; 197 } 198 off = bpt - pt; 199 len = ept - bpt; 200 if ((npt = realloc(pt, ptsize *= 2)) == NULL) 201 goto err; 202 pt = npt; 203 bpt = pt + off; 204 ept = pt + ptsize; 205 memmove(ept - len, bpt, len); 206 bpt = ept - len; 207 } 208 if (!first) 209 *--bpt = '/'; 210 bpt -= dp->d_namlen; 211 memmove(bpt, dp->d_name, dp->d_namlen); 212 (void)closedir(dir); 213 214 /* Truncate any file name. */ 215 *bup = '\0'; 216 } 217 218 notfound: 219 /* 220 * If readdir set errno, use it, not any saved error; otherwise, 221 * didn't find the current directory in its parent directory, set 222 * errno to ENOENT. 223 */ 224 if (!errno) 225 errno = save_errno ? save_errno : ENOENT; 226 /* FALLTHROUGH */ 227 err: 228 if (ptsize) 229 free(pt); 230 if (up) 231 free(up); 232 if (dir) 233 (void)closedir(dir); 234 return (NULL); 235 } 236 237 #endif /* !defined(HAVE_GETCWD) */ 238 239 #pragma ident "%Z%%M% %I% %E% SMI" 240