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