1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1989, 1991, 1993, 1995 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. Neither the name of the University nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 */ 31 32 #include "namespace.h" 33 #include <sys/param.h> 34 #include <sys/stat.h> 35 36 #include <dirent.h> 37 #include <errno.h> 38 #include <fcntl.h> 39 #include <stdio.h> 40 #include <stdlib.h> 41 #include <string.h> 42 #include <unistd.h> 43 #include <ssp/ssp.h> 44 #include "un-namespace.h" 45 46 #include "gen-private.h" 47 48 #define ISDOT(dp) \ 49 (dp->d_name[0] == '.' && (dp->d_name[1] == '\0' || \ 50 (dp->d_name[1] == '.' && dp->d_name[2] == '\0'))) 51 52 extern int __getcwd(char *, size_t); 53 54 char * 55 __ssp_real(getcwd)(char *pt, size_t size) 56 { 57 struct dirent *dp; 58 DIR *dir = NULL; 59 dev_t dev; 60 ino_t ino; 61 int first; 62 char *bpt; 63 struct stat s; 64 dev_t root_dev; 65 ino_t root_ino; 66 size_t ptsize; 67 int save_errno; 68 char *ept, c; 69 int fd; 70 71 /* 72 * If no buffer specified by the user, allocate one as necessary. 73 * If a buffer is specified, the size has to be non-zero. The path 74 * is built from the end of the buffer backwards. 75 */ 76 if (pt) { 77 ptsize = 0; 78 if (!size) { 79 errno = EINVAL; 80 return (NULL); 81 } 82 if (size == 1) { 83 errno = ERANGE; 84 return (NULL); 85 } 86 ept = pt + size; 87 } else { 88 if ((pt = malloc(ptsize = PATH_MAX)) == NULL) 89 return (NULL); 90 ept = pt + ptsize; 91 } 92 if (__getcwd(pt, ept - pt) == 0) { 93 if (*pt != '/') { 94 bpt = pt; 95 ept = pt + strlen(pt) - 1; 96 while (bpt < ept) { 97 c = *bpt; 98 *bpt++ = *ept; 99 *ept-- = c; 100 } 101 } 102 return (pt); 103 } 104 bpt = ept - 1; 105 *bpt = '\0'; 106 107 /* Save root values, so know when to stop. */ 108 if (stat("/", &s)) 109 goto err; 110 root_dev = s.st_dev; 111 root_ino = s.st_ino; 112 113 errno = 0; /* XXX readdir has no error return. */ 114 115 for (first = 1;; first = 0) { 116 /* Stat the current level. */ 117 if (dir != NULL ? _fstat(_dirfd(dir), &s) : lstat(".", &s)) 118 goto err; 119 120 /* Save current node values. */ 121 ino = s.st_ino; 122 dev = s.st_dev; 123 124 /* Check for reaching root. */ 125 if (root_dev == dev && root_ino == ino) { 126 *--bpt = '/'; 127 /* 128 * It's unclear that it's a requirement to copy the 129 * path to the beginning of the buffer, but it's always 130 * been that way and stuff would probably break. 131 */ 132 bcopy(bpt, pt, ept - bpt); 133 if (dir) 134 (void) closedir(dir); 135 return (pt); 136 } 137 138 /* Open and stat parent directory. */ 139 fd = _openat(dir != NULL ? _dirfd(dir) : AT_FDCWD, 140 "..", O_RDONLY | O_CLOEXEC); 141 if (fd == -1) 142 goto err; 143 if (dir) 144 (void) closedir(dir); 145 if (!(dir = fdopendir(fd)) || _fstat(_dirfd(dir), &s)) { 146 _close(fd); 147 goto err; 148 } 149 150 /* 151 * If it's a mount point, have to stat each element because 152 * the inode number in the directory is for the entry in the 153 * parent directory, not the inode number of the mounted file. 154 */ 155 save_errno = 0; 156 if (s.st_dev == dev) { 157 for (;;) { 158 if (!(dp = readdir(dir))) 159 goto notfound; 160 if (dp->d_fileno == ino) 161 break; 162 } 163 } else 164 for (;;) { 165 if (!(dp = readdir(dir))) 166 goto notfound; 167 if (ISDOT(dp)) 168 continue; 169 170 /* Save the first error for later. */ 171 if (fstatat(_dirfd(dir), dp->d_name, &s, 172 AT_SYMLINK_NOFOLLOW)) { 173 if (!save_errno) 174 save_errno = errno; 175 errno = 0; 176 continue; 177 } 178 if (s.st_dev == dev && s.st_ino == ino) 179 break; 180 } 181 182 /* 183 * Check for length of the current name, preceding slash, 184 * leading slash. 185 */ 186 while (bpt - pt < dp->d_namlen + (first ? 1 : 2)) { 187 size_t len, off; 188 189 if (!ptsize) { 190 errno = ERANGE; 191 goto err; 192 } 193 off = bpt - pt; 194 len = ept - bpt; 195 if ((pt = reallocf(pt, ptsize *= 2)) == NULL) 196 goto err; 197 bpt = pt + off; 198 ept = pt + ptsize; 199 bcopy(bpt, ept - len, len); 200 bpt = ept - len; 201 } 202 if (!first) 203 *--bpt = '/'; 204 bpt -= dp->d_namlen; 205 bcopy(dp->d_name, bpt, dp->d_namlen); 206 } 207 208 notfound: 209 /* 210 * If readdir set errno, use it, not any saved error; otherwise, 211 * didn't find the current directory in its parent directory, set 212 * errno to ENOENT. 213 */ 214 if (!errno) 215 errno = save_errno ? save_errno : ENOENT; 216 /* FALLTHROUGH */ 217 err: 218 save_errno = errno; 219 220 if (ptsize) 221 free(pt); 222 if (dir) 223 (void) closedir(dir); 224 225 errno = save_errno; 226 return (NULL); 227 } 228