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 #include "gen-private.h" 50 51 #define ISDOT(dp) \ 52 (dp->d_name[0] == '.' && (dp->d_name[1] == '\0' || \ 53 (dp->d_name[1] == '.' && dp->d_name[2] == '\0'))) 54 55 extern int __getcwd(char *, size_t); 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; 68 struct stat s; 69 dev_t root_dev; 70 ino_t root_ino; 71 size_t ptsize; 72 int save_errno; 73 char *ept, c; 74 int fd; 75 76 /* 77 * If no buffer specified by the user, allocate one as necessary. 78 * If a buffer is specified, the size has to be non-zero. The path 79 * is built from the end of the buffer backwards. 80 */ 81 if (pt) { 82 ptsize = 0; 83 if (!size) { 84 errno = EINVAL; 85 return (NULL); 86 } 87 if (size == 1) { 88 errno = ERANGE; 89 return (NULL); 90 } 91 ept = pt + size; 92 } else { 93 if ((pt = malloc(ptsize = PATH_MAX)) == NULL) 94 return (NULL); 95 ept = pt + ptsize; 96 } 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 bpt = ept - 1; 110 *bpt = '\0'; 111 112 /* Save root values, so know when to stop. */ 113 if (stat("/", &s)) 114 goto err; 115 root_dev = s.st_dev; 116 root_ino = s.st_ino; 117 118 errno = 0; /* XXX readdir has no error return. */ 119 120 for (first = 1;; first = 0) { 121 /* Stat the current level. */ 122 if (dir != NULL ? _fstat(_dirfd(dir), &s) : lstat(".", &s)) 123 goto err; 124 125 /* Save current node values. */ 126 ino = s.st_ino; 127 dev = s.st_dev; 128 129 /* Check for reaching root. */ 130 if (root_dev == dev && root_ino == ino) { 131 *--bpt = '/'; 132 /* 133 * It's unclear that it's a requirement to copy the 134 * path to the beginning of the buffer, but it's always 135 * been that way and stuff would probably break. 136 */ 137 bcopy(bpt, pt, ept - bpt); 138 if (dir) 139 (void) closedir(dir); 140 return (pt); 141 } 142 143 /* Open and stat parent directory. */ 144 fd = _openat(dir != NULL ? _dirfd(dir) : AT_FDCWD, 145 "..", O_RDONLY | O_CLOEXEC); 146 if (fd == -1) 147 goto err; 148 if (dir) 149 (void) closedir(dir); 150 if (!(dir = fdopendir(fd)) || _fstat(_dirfd(dir), &s)) { 151 _close(fd); 152 goto err; 153 } 154 155 /* 156 * If it's a mount point, have to stat each element because 157 * the inode number in the directory is for the entry in the 158 * parent directory, not the inode number of the mounted file. 159 */ 160 save_errno = 0; 161 if (s.st_dev == dev) { 162 for (;;) { 163 if (!(dp = readdir(dir))) 164 goto notfound; 165 if (dp->d_fileno == ino) 166 break; 167 } 168 } else 169 for (;;) { 170 if (!(dp = readdir(dir))) 171 goto notfound; 172 if (ISDOT(dp)) 173 continue; 174 175 /* Save the first error for later. */ 176 if (fstatat(_dirfd(dir), dp->d_name, &s, 177 AT_SYMLINK_NOFOLLOW)) { 178 if (!save_errno) 179 save_errno = errno; 180 errno = 0; 181 continue; 182 } 183 if (s.st_dev == dev && s.st_ino == ino) 184 break; 185 } 186 187 /* 188 * Check for length of the current name, preceding slash, 189 * leading slash. 190 */ 191 while (bpt - pt < dp->d_namlen + (first ? 1 : 2)) { 192 size_t len, off; 193 194 if (!ptsize) { 195 errno = ERANGE; 196 goto err; 197 } 198 off = bpt - pt; 199 len = ept - bpt; 200 if ((pt = reallocf(pt, ptsize *= 2)) == NULL) 201 goto err; 202 bpt = pt + off; 203 ept = pt + ptsize; 204 bcopy(bpt, ept - len, len); 205 bpt = ept - len; 206 } 207 if (!first) 208 *--bpt = '/'; 209 bpt -= dp->d_namlen; 210 bcopy(dp->d_name, bpt, dp->d_namlen); 211 } 212 213 notfound: 214 /* 215 * If readdir set errno, use it, not any saved error; otherwise, 216 * didn't find the current directory in its parent directory, set 217 * errno to ENOENT. 218 */ 219 if (!errno) 220 errno = save_errno ? save_errno : ENOENT; 221 /* FALLTHROUGH */ 222 err: 223 save_errno = errno; 224 225 if (ptsize) 226 free(pt); 227 if (dir) 228 (void) closedir(dir); 229 230 errno = save_errno; 231 return (NULL); 232 } 233