1/*- 2 * See the file LICENSE for redistribution information. 3 * 4 * Copyright (c) 1996,2008 Oracle. All rights reserved. 5 */ 6/* 7 * Copyright (c) 1989, 1991, 1993 8 * The Regents of the University of California. All rights reserved. 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 * $Id: getcwd.c,v 12.10 2008/01/08 20:58:07 bostic Exp $ 35 */ 36 37#include "db_config.h" 38 39#include "db_int.h" 40 41#ifdef HAVE_SYSTEM_INCLUDE_FILES 42#if HAVE_DIRENT_H 43# include <dirent.h> 44# define NAMLEN(dirent) strlen((dirent)->d_name) 45#else 46# define dirent direct 47# define NAMLEN(dirent) (dirent)->d_namlen 48# if HAVE_SYS_NDIR_H 49# include <sys/ndir.h> 50# endif 51# if HAVE_SYS_DIR_H 52# include <sys/dir.h> 53# endif 54# if HAVE_NDIR_H 55# include <ndir.h> 56# endif 57#endif 58#endif 59 60#define ISDOT(dp) \ 61 (dp->d_name[0] == '.' && (dp->d_name[1] == '\0' || \ 62 (dp->d_name[1] == '.' && dp->d_name[2] == '\0'))) 63 64#ifndef dirfd 65#define dirfd(dirp) ((dirp)->dd_fd) 66#endif 67 68/* 69 * getcwd -- 70 * Get the current working directory. 71 * 72 * PUBLIC: #ifndef HAVE_GETCWD 73 * PUBLIC: char *getcwd __P((char *, size_t)); 74 * PUBLIC: #endif 75 */ 76char * 77getcwd(pt, size) 78 char *pt; 79 size_t size; 80{ 81 register struct dirent *dp; 82 register DIR *dir; 83 register dev_t dev; 84 register ino_t ino; 85 register int first; 86 register char *bpt, *bup; 87 struct stat s; 88 dev_t root_dev; 89 ino_t root_ino; 90 size_t ptsize, upsize; 91 int ret, save_errno; 92 char *ept, *eup, *up; 93 94 /* 95 * If no buffer specified by the user, allocate one as necessary. 96 * If a buffer is specified, the size has to be non-zero. The path 97 * is built from the end of the buffer backwards. 98 */ 99 if (pt) { 100 ptsize = 0; 101 if (!size) { 102 __os_set_errno(EINVAL); 103 return (NULL); 104 } 105 if (size == 1) { 106 __os_set_errno(ERANGE); 107 return (NULL); 108 } 109 ept = pt + size; 110 } else { 111 if ((ret = 112 __os_malloc(NULL, ptsize = 1024 - 4, &pt)) != 0) { 113 __os_set_errno(ret); 114 return (NULL); 115 } 116 ept = pt + ptsize; 117 } 118 bpt = ept - 1; 119 *bpt = '\0'; 120 121 /* 122 * Allocate bytes (1024 - malloc space) for the string of "../"'s. 123 * Should always be enough (it's 340 levels). If it's not, allocate 124 * as necessary. Special case the first stat, it's ".", not "..". 125 */ 126 if ((ret = __os_malloc(NULL, upsize = 1024 - 4, &up)) != 0) 127 goto err; 128 eup = up + 1024; 129 bup = up; 130 up[0] = '.'; 131 up[1] = '\0'; 132 133 /* Save root values, so know when to stop. */ 134 if (stat("/", &s)) 135 goto err; 136 root_dev = s.st_dev; 137 root_ino = s.st_ino; 138 139 __os_set_errno(0); /* XXX readdir has no error return. */ 140 141 for (first = 1;; first = 0) { 142 /* Stat the current level. */ 143 if (lstat(up, &s)) 144 goto err; 145 146 /* Save current node values. */ 147 ino = s.st_ino; 148 dev = s.st_dev; 149 150 /* Check for reaching root. */ 151 if (root_dev == dev && root_ino == ino) { 152 *--bpt = PATH_SEPARATOR[0]; 153 /* 154 * It's unclear that it's a requirement to copy the 155 * path to the beginning of the buffer, but it's always 156 * been that way and stuff would probably break. 157 */ 158 bcopy(bpt, pt, ept - bpt); 159 __os_free(NULL, up); 160 return (pt); 161 } 162 163 /* 164 * Build pointer to the parent directory, allocating memory 165 * as necessary. Max length is 3 for "../", the largest 166 * possible component name, plus a trailing NULL. 167 */ 168 if (bup + 3 + MAXNAMLEN + 1 >= eup) { 169 if (__os_realloc(NULL, upsize *= 2, &up) != 0) 170 goto err; 171 bup = up; 172 eup = up + upsize; 173 } 174 *bup++ = '.'; 175 *bup++ = '.'; 176 *bup = '\0'; 177 178 /* Open and stat parent directory. */ 179 if (!(dir = opendir(up)) || fstat(dirfd(dir), &s)) 180 goto err; 181 182 /* Add trailing slash for next directory. */ 183 *bup++ = PATH_SEPARATOR[0]; 184 185 /* 186 * If it's a mount point, have to stat each element because 187 * the inode number in the directory is for the entry in the 188 * parent directory, not the inode number of the mounted file. 189 */ 190 save_errno = 0; 191 if (s.st_dev == dev) { 192 for (;;) { 193 if (!(dp = readdir(dir))) 194 goto notfound; 195 if (dp->d_fileno == ino) 196 break; 197 } 198 } else 199 for (;;) { 200 if (!(dp = readdir(dir))) 201 goto notfound; 202 if (ISDOT(dp)) 203 continue; 204 bcopy(dp->d_name, bup, dp->d_namlen + 1); 205 206 /* Save the first error for later. */ 207 if (lstat(up, &s)) { 208 if (save_errno == 0) 209 save_errno = __os_get_errno(); 210 __os_set_errno(0); 211 continue; 212 } 213 if (s.st_dev == dev && s.st_ino == ino) 214 break; 215 } 216 217 /* 218 * Check for length of the current name, preceding slash, 219 * leading slash. 220 */ 221 if (bpt - pt < dp->d_namlen + (first ? 1 : 2)) { 222 size_t len, off; 223 224 if (!ptsize) { 225 __os_set_errno(ERANGE); 226 goto err; 227 } 228 off = bpt - pt; 229 len = ept - bpt; 230 if (__os_realloc(NULL, ptsize *= 2, &pt) != 0) 231 goto err; 232 bpt = pt + off; 233 ept = pt + ptsize; 234 bcopy(bpt, ept - len, len); 235 bpt = ept - len; 236 } 237 if (!first) 238 *--bpt = PATH_SEPARATOR[0]; 239 bpt -= dp->d_namlen; 240 bcopy(dp->d_name, bpt, dp->d_namlen); 241 (void)closedir(dir); 242 243 /* Truncate any file name. */ 244 *bup = '\0'; 245 } 246 247notfound: 248 /* 249 * If readdir set errno, use it, not any saved error; otherwise, 250 * didn't find the current directory in its parent directory, set 251 * errno to ENOENT. 252 */ 253 if (__os_get_errno_ret_zero() == 0) 254 __os_set_errno(save_errno == 0 ? ENOENT : save_errno); 255 /* FALLTHROUGH */ 256err: 257 if (ptsize) 258 __os_free(NULL, pt); 259 __os_free(NULL, up); 260 return (NULL); 261} 262