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) 31static 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 55extern int __getcwd(char *, size_t); 56 57char * 58getcwd(char *pt, 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; 66 struct stat s; 67 dev_t root_dev; 68 ino_t root_ino; 69 size_t ptsize; 70 int save_errno; 71 char *ept, c; 72 int fd; 73 74 /* 75 * If no buffer specified by the user, allocate one as necessary. 76 * If a buffer is specified, the size has to be non-zero. The path 77 * is built from the end of the buffer backwards. 78 */ 79 if (pt) { 80 ptsize = 0; 81 if (!size) { 82 errno = EINVAL; 83 return (NULL); 84 } 85 if (size == 1) { 86 errno = ERANGE; 87 return (NULL); 88 } 89 ept = pt + size; 90 } else { 91 if ((pt = malloc(ptsize = PATH_MAX)) == NULL) 92 return (NULL); 93 ept = pt + ptsize; 94 } 95 if (__getcwd(pt, ept - pt) == 0) { 96 if (*pt != '/') { 97 bpt = pt; 98 ept = pt + strlen(pt) - 1; 99 while (bpt < ept) { 100 c = *bpt; 101 *bpt++ = *ept; 102 *ept-- = c; 103 } 104 } 105 return (pt); 106 } 107 bpt = ept - 1; 108 *bpt = '\0'; 109 110 /* Save root values, so know when to stop. */ 111 if (stat("/", &s)) 112 goto err; 113 root_dev = s.st_dev; 114 root_ino = s.st_ino; 115 116 errno = 0; /* XXX readdir has no error return. */ 117 118 for (first = 1;; first = 0) { 119 /* Stat the current level. */ 120 if (dir != NULL ? _fstat(_dirfd(dir), &s) : lstat(".", &s)) 121 goto err; 122 123 /* Save current node values. */ 124 ino = s.st_ino; 125 dev = s.st_dev; 126 127 /* Check for reaching root. */ 128 if (root_dev == dev && root_ino == ino) { 129 *--bpt = '/'; 130 /* 131 * It's unclear that it's a requirement to copy the 132 * path to the beginning of the buffer, but it's always 133 * been that way and stuff would probably break. 134 */ 135 bcopy(bpt, pt, ept - bpt); 136 if (dir) 137 (void) closedir(dir); 138 return (pt); 139 } 140 141 /* Open and stat parent directory. */ 142 fd = _openat(dir != NULL ? _dirfd(dir) : AT_FDCWD, 143 "..", O_RDONLY | O_CLOEXEC); 144 if (fd == -1) 145 goto err; 146 if (dir) 147 (void) closedir(dir); 148 if (!(dir = fdopendir(fd)) || _fstat(_dirfd(dir), &s)) { 149 _close(fd); 150 goto err; 151 } 152 153 /* 154 * If it's a mount point, have to stat each element because 155 * the inode number in the directory is for the entry in the 156 * parent directory, not the inode number of the mounted file. 157 */ 158 save_errno = 0; 159 if (s.st_dev == dev) { 160 for (;;) { 161 if (!(dp = readdir(dir))) 162 goto notfound; 163 if (dp->d_fileno == ino) 164 break; 165 } 166 } else 167 for (;;) { 168 if (!(dp = readdir(dir))) 169 goto notfound; 170 if (ISDOT(dp)) 171 continue; 172 173 /* Save the first error for later. */ 174 if (fstatat(_dirfd(dir), dp->d_name, &s, 175 AT_SYMLINK_NOFOLLOW)) { 176 if (!save_errno) 177 save_errno = errno; 178 errno = 0; 179 continue; 180 } 181 if (s.st_dev == dev && s.st_ino == ino) 182 break; 183 } 184 185 /* 186 * Check for length of the current name, preceding slash, 187 * leading slash. 188 */ 189 while (bpt - pt < dp->d_namlen + (first ? 1 : 2)) { 190 size_t len, off; 191 192 if (!ptsize) { 193 errno = ERANGE; 194 goto err; 195 } 196 off = bpt - pt; 197 len = ept - bpt; 198 if ((pt = reallocf(pt, ptsize *= 2)) == NULL) 199 goto err; 200 bpt = pt + off; 201 ept = pt + ptsize; 202 bcopy(bpt, ept - len, len); 203 bpt = ept - len; 204 } 205 if (!first) 206 *--bpt = '/'; 207 bpt -= dp->d_namlen; 208 bcopy(dp->d_name, bpt, dp->d_namlen); 209 } 210 211notfound: 212 /* 213 * If readdir set errno, use it, not any saved error; otherwise, 214 * didn't find the current directory in its parent directory, set 215 * errno to ENOENT. 216 */ 217 if (!errno) 218 errno = save_errno ? save_errno : ENOENT; 219 /* FALLTHROUGH */ 220err: 221 save_errno = errno; 222 223 if (ptsize) 224 free(pt); 225 if (dir) 226 (void) closedir(dir); 227 228 errno = save_errno; 229 return (NULL); 230} 231