1 /* 2 * Copyright (c) 1989, 1991, 1993, 1995 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 * 4. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 */ 29 30 #if defined(LIBC_SCCS) && !defined(lint) 31 static char sccsid[] = "@(#)getcwd.c 8.5 (Berkeley) 2/7/95"; 32 #endif /* LIBC_SCCS and not lint */ 33 #include <sys/cdefs.h> 34 __FBSDID("$FreeBSD$"); 35 36 #include "namespace.h" 37 #include <sys/param.h> 38 #include <sys/stat.h> 39 40 #include <dirent.h> 41 #include <errno.h> 42 #include <fcntl.h> 43 #include <stdio.h> 44 #include <stdlib.h> 45 #include <string.h> 46 #include <unistd.h> 47 #include "un-namespace.h" 48 49 #define ISDOT(dp) \ 50 (dp->d_name[0] == '.' && (dp->d_name[1] == '\0' || \ 51 (dp->d_name[1] == '.' && dp->d_name[2] == '\0'))) 52 53 extern int __getcwd(char *, size_t); 54 55 char * 56 getcwd(pt, size) 57 char *pt; 58 size_t size; 59 { 60 struct dirent *dp; 61 DIR *dir = NULL; 62 dev_t dev; 63 ino_t ino; 64 int first; 65 char *bpt, *bup; 66 struct stat s; 67 dev_t root_dev; 68 ino_t root_ino; 69 size_t ptsize, upsize; 70 int save_errno; 71 char *ept, *eup, *up, c; 72 73 /* 74 * If no buffer specified by the user, allocate one as necessary. 75 * If a buffer is specified, the size has to be non-zero. The path 76 * is built from the end of the buffer backwards. 77 */ 78 if (pt) { 79 ptsize = 0; 80 if (!size) { 81 errno = EINVAL; 82 return (NULL); 83 } 84 if (size == 1) { 85 errno = ERANGE; 86 return (NULL); 87 } 88 ept = pt + size; 89 } else { 90 if ((pt = malloc(ptsize = PATH_MAX)) == NULL) 91 return (NULL); 92 ept = pt + ptsize; 93 } 94 if (__getcwd(pt, ept - pt) == 0) { 95 if (*pt != '/') { 96 bpt = pt; 97 ept = pt + strlen(pt) - 1; 98 while (bpt < ept) { 99 c = *bpt; 100 *bpt++ = *ept; 101 *ept-- = c; 102 } 103 } 104 return (pt); 105 } 106 bpt = ept - 1; 107 *bpt = '\0'; 108 109 /* 110 * Allocate 1024 bytes for the string of "../"'s. 111 * Should always be enough. If it's not, allocate 112 * as necessary. Special case the first stat, it's ".", not "..". 113 */ 114 if ((up = malloc(upsize = 1024)) == NULL) 115 goto err; 116 eup = up + upsize; 117 bup = up; 118 up[0] = '.'; 119 up[1] = '\0'; 120 121 /* Save root values, so know when to stop. */ 122 if (stat("/", &s)) 123 goto err; 124 root_dev = s.st_dev; 125 root_ino = s.st_ino; 126 127 errno = 0; /* XXX readdir has no error return. */ 128 129 for (first = 1;; first = 0) { 130 /* Stat the current level. */ 131 if (lstat(up, &s)) 132 goto err; 133 134 /* Save current node values. */ 135 ino = s.st_ino; 136 dev = s.st_dev; 137 138 /* Check for reaching root. */ 139 if (root_dev == dev && root_ino == ino) { 140 *--bpt = '/'; 141 /* 142 * It's unclear that it's a requirement to copy the 143 * path to the beginning of the buffer, but it's always 144 * been that way and stuff would probably break. 145 */ 146 bcopy(bpt, pt, ept - bpt); 147 free(up); 148 return (pt); 149 } 150 151 /* 152 * Build pointer to the parent directory, allocating memory 153 * as necessary. Max length is 3 for "../", the largest 154 * possible component name, plus a trailing NUL. 155 */ 156 while (bup + 3 + MAXNAMLEN + 1 >= eup) { 157 if ((up = reallocf(up, upsize *= 2)) == NULL) 158 goto err; 159 bup = up; 160 eup = up + upsize; 161 } 162 *bup++ = '.'; 163 *bup++ = '.'; 164 *bup = '\0'; 165 166 /* Open and stat parent directory. */ 167 if (!(dir = opendir(up)) || _fstat(dirfd(dir), &s)) 168 goto err; 169 170 /* Add trailing slash for next directory. */ 171 *bup++ = '/'; 172 *bup = '\0'; 173 174 /* 175 * If it's a mount point, have to stat each element because 176 * the inode number in the directory is for the entry in the 177 * parent directory, not the inode number of the mounted file. 178 */ 179 save_errno = 0; 180 if (s.st_dev == dev) { 181 for (;;) { 182 if (!(dp = readdir(dir))) 183 goto notfound; 184 if (dp->d_fileno == ino) 185 break; 186 } 187 } else 188 for (;;) { 189 if (!(dp = readdir(dir))) 190 goto notfound; 191 if (ISDOT(dp)) 192 continue; 193 bcopy(dp->d_name, bup, dp->d_namlen + 1); 194 195 /* Save the first error for later. */ 196 if (lstat(up, &s)) { 197 if (!save_errno) 198 save_errno = errno; 199 errno = 0; 200 continue; 201 } 202 if (s.st_dev == dev && s.st_ino == ino) 203 break; 204 } 205 206 /* 207 * Check for length of the current name, preceding slash, 208 * leading slash. 209 */ 210 while (bpt - pt < dp->d_namlen + (first ? 1 : 2)) { 211 size_t len, off; 212 213 if (!ptsize) { 214 errno = ERANGE; 215 goto err; 216 } 217 off = bpt - pt; 218 len = ept - bpt; 219 if ((pt = reallocf(pt, ptsize *= 2)) == NULL) 220 goto err; 221 bpt = pt + off; 222 ept = pt + ptsize; 223 bcopy(bpt, ept - len, len); 224 bpt = ept - len; 225 } 226 if (!first) 227 *--bpt = '/'; 228 bpt -= dp->d_namlen; 229 bcopy(dp->d_name, bpt, dp->d_namlen); 230 (void) closedir(dir); 231 dir = NULL; 232 233 /* Truncate any file name. */ 234 *bup = '\0'; 235 } 236 237 notfound: 238 /* 239 * If readdir set errno, use it, not any saved error; otherwise, 240 * didn't find the current directory in its parent directory, set 241 * errno to ENOENT. 242 */ 243 if (!errno) 244 errno = save_errno ? save_errno : ENOENT; 245 /* FALLTHROUGH */ 246 err: 247 save_errno = errno; 248 249 if (ptsize) 250 free(pt); 251 if (dir) 252 (void) closedir(dir); 253 free(up); 254 255 errno = save_errno; 256 return (NULL); 257 } 258