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 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34 #if defined(LIBC_SCCS) && !defined(lint) 35 static char sccsid[] = "@(#)getcwd.c 8.5 (Berkeley) 2/7/95"; 36 #endif /* LIBC_SCCS and not lint */ 37 #include <sys/cdefs.h> 38 __FBSDID("$FreeBSD$"); 39 40 #include "namespace.h" 41 #include <sys/param.h> 42 #include <sys/stat.h> 43 44 #include <dirent.h> 45 #include <errno.h> 46 #include <fcntl.h> 47 #include <stdio.h> 48 #include <stdlib.h> 49 #include <string.h> 50 #include <unistd.h> 51 #include "un-namespace.h" 52 53 #define ISDOT(dp) \ 54 (dp->d_name[0] == '.' && (dp->d_name[1] == '\0' || \ 55 (dp->d_name[1] == '.' && dp->d_name[2] == '\0'))) 56 57 extern int __getcwd(char *, size_t); 58 59 char * 60 getcwd(pt, size) 61 char *pt; 62 size_t size; 63 { 64 struct dirent *dp; 65 DIR *dir = NULL; 66 dev_t dev; 67 ino_t ino; 68 int first; 69 char *bpt, *bup; 70 struct stat s; 71 dev_t root_dev; 72 ino_t root_ino; 73 size_t ptsize, upsize; 74 int save_errno; 75 char *ept, *eup, *up, c; 76 77 /* 78 * If no buffer specified by the user, allocate one as necessary. 79 * If a buffer is specified, the size has to be non-zero. The path 80 * is built from the end of the buffer backwards. 81 */ 82 if (pt) { 83 ptsize = 0; 84 if (!size) { 85 errno = EINVAL; 86 return (NULL); 87 } 88 if (size == 1) { 89 errno = ERANGE; 90 return (NULL); 91 } 92 ept = pt + size; 93 } else { 94 if ((pt = malloc(ptsize = 1024 - 4)) == NULL) 95 return (NULL); 96 ept = pt + ptsize; 97 } 98 #if !defined(__NETBSD_SYSCALLS) 99 if (__getcwd(pt, ept - pt) == 0) { 100 if (*pt != '/') { 101 bpt = pt; 102 ept = pt + strlen(pt) - 1; 103 while (bpt < ept) { 104 c = *bpt; 105 *bpt++ = *ept; 106 *ept-- = c; 107 } 108 } 109 return (pt); 110 } 111 #endif 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 bcopy(bpt, pt, 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 NUL. 161 */ 162 if (bup + 3 + MAXNAMLEN + 1 >= eup) { 163 if ((up = reallocf(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 *bup = '\0'; 179 180 /* 181 * If it's a mount point, have to stat each element because 182 * the inode number in the directory is for the entry in the 183 * parent directory, not the inode number of the mounted file. 184 */ 185 save_errno = 0; 186 if (s.st_dev == dev) { 187 for (;;) { 188 if (!(dp = readdir(dir))) 189 goto notfound; 190 if (dp->d_fileno == ino) 191 break; 192 } 193 } else 194 for (;;) { 195 if (!(dp = readdir(dir))) 196 goto notfound; 197 if (ISDOT(dp)) 198 continue; 199 bcopy(dp->d_name, bup, dp->d_namlen + 1); 200 201 /* Save the first error for later. */ 202 if (lstat(up, &s)) { 203 if (!save_errno) 204 save_errno = errno; 205 errno = 0; 206 continue; 207 } 208 if (s.st_dev == dev && s.st_ino == ino) 209 break; 210 } 211 212 /* 213 * Check for length of the current name, preceding slash, 214 * leading slash. 215 */ 216 if (bpt - pt < dp->d_namlen + (first ? 1 : 2)) { 217 size_t len, off; 218 219 if (!ptsize) { 220 errno = ERANGE; 221 goto err; 222 } 223 off = bpt - pt; 224 len = ept - bpt; 225 if ((pt = reallocf(pt, ptsize *= 2)) == NULL) 226 goto err; 227 bpt = pt + off; 228 ept = pt + ptsize; 229 bcopy(bpt, ept - len, len); 230 bpt = ept - len; 231 } 232 if (!first) 233 *--bpt = '/'; 234 bpt -= dp->d_namlen; 235 bcopy(dp->d_name, bpt, dp->d_namlen); 236 (void) closedir(dir); 237 dir = NULL; 238 239 /* Truncate any file name. */ 240 *bup = '\0'; 241 } 242 243 notfound: 244 /* 245 * If readdir set errno, use it, not any saved error; otherwise, 246 * didn't find the current directory in its parent directory, set 247 * errno to ENOENT. 248 */ 249 if (!errno) 250 errno = save_errno ? save_errno : ENOENT; 251 /* FALLTHROUGH */ 252 err: 253 save_errno = errno; 254 255 if (ptsize) 256 free(pt); 257 if (dir) 258 (void) closedir(dir); 259 free(up); 260 261 errno = save_errno; 262 return (NULL); 263 } 264