1 /*- 2 * Copyright (c) 1983, 1993 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[] = "@(#)opendir.c 8.8 (Berkeley) 5/1/95"; 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/mount.h> 39 #include <sys/stat.h> 40 41 #include <dirent.h> 42 #include <errno.h> 43 #include <fcntl.h> 44 #include <stdlib.h> 45 #include <string.h> 46 #include <unistd.h> 47 #include "un-namespace.h" 48 49 #include "telldir.h" 50 51 static DIR * __opendir_common(int, const char *, int); 52 53 /* 54 * Open a directory. 55 */ 56 DIR * 57 opendir(const char *name) 58 { 59 60 return (__opendir2(name, DTF_HIDEW|DTF_NODUP)); 61 } 62 63 /* 64 * Open a directory with existing file descriptor. 65 */ 66 DIR * 67 fdopendir(int fd) 68 { 69 struct stat statb; 70 71 /* Check that fd is associated with a directory. */ 72 if (_fstat(fd, &statb) != 0) 73 return (NULL); 74 if (!S_ISDIR(statb.st_mode)) { 75 errno = ENOTDIR; 76 return (NULL); 77 } 78 if (_fcntl(fd, F_SETFD, FD_CLOEXEC) == -1) 79 return (NULL); 80 return (__opendir_common(fd, NULL, DTF_HIDEW|DTF_NODUP)); 81 } 82 83 DIR * 84 __opendir2(const char *name, int flags) 85 { 86 int fd; 87 DIR *dir; 88 int saved_errno; 89 90 if ((fd = _open(name, 91 O_RDONLY | O_NONBLOCK | O_DIRECTORY | O_CLOEXEC)) == -1) 92 return (NULL); 93 94 dir = __opendir_common(fd, name, flags); 95 if (dir == NULL) { 96 saved_errno = errno; 97 _close(fd); 98 errno = saved_errno; 99 } 100 return (dir); 101 } 102 103 static int 104 opendir_compar(const void *p1, const void *p2) 105 { 106 107 return (strcmp((*(const struct dirent **)p1)->d_name, 108 (*(const struct dirent **)p2)->d_name)); 109 } 110 111 /* 112 * Common routine for opendir(3), __opendir2(3) and fdopendir(3). 113 */ 114 static DIR * 115 __opendir_common(int fd, const char *name, int flags) 116 { 117 DIR *dirp; 118 int incr; 119 int saved_errno; 120 int unionstack; 121 int fd2; 122 123 if ((dirp = malloc(sizeof(DIR) + sizeof(struct _telldir))) == NULL) 124 return (NULL); 125 126 dirp->dd_td = (struct _telldir *)((char *)dirp + sizeof(DIR)); 127 LIST_INIT(&dirp->dd_td->td_locq); 128 dirp->dd_td->td_loccnt = 0; 129 130 /* 131 * Use the system page size if that is a multiple of DIRBLKSIZ. 132 * Hopefully this can be a big win someday by allowing page 133 * trades to user space to be done by _getdirentries(). 134 */ 135 incr = getpagesize(); 136 if ((incr % DIRBLKSIZ) != 0) 137 incr = DIRBLKSIZ; 138 139 /* 140 * Determine whether this directory is the top of a union stack. 141 */ 142 if (flags & DTF_NODUP) { 143 struct statfs sfb; 144 145 if (_fstatfs(fd, &sfb) < 0) 146 goto fail; 147 unionstack = !strcmp(sfb.f_fstypename, "unionfs") 148 || (sfb.f_flags & MNT_UNION); 149 } else { 150 unionstack = 0; 151 } 152 153 if (unionstack) { 154 int len = 0; 155 int space = 0; 156 char *buf = 0; 157 char *ddptr = 0; 158 char *ddeptr; 159 int n; 160 struct dirent **dpv; 161 162 /* 163 * The strategy here is to read all the directory 164 * entries into a buffer, sort the buffer, and 165 * remove duplicate entries by setting the inode 166 * number to zero. 167 */ 168 169 do { 170 /* 171 * Always make at least DIRBLKSIZ bytes 172 * available to _getdirentries 173 */ 174 if (space < DIRBLKSIZ) { 175 space += incr; 176 len += incr; 177 buf = reallocf(buf, len); 178 if (buf == NULL) 179 goto fail; 180 ddptr = buf + (len - space); 181 } 182 183 n = _getdirentries(fd, ddptr, space, &dirp->dd_seek); 184 if (n > 0) { 185 ddptr += n; 186 space -= n; 187 } 188 } while (n > 0); 189 190 ddeptr = ddptr; 191 flags |= __DTF_READALL; 192 193 /* 194 * Re-open the directory. 195 * This has the effect of rewinding back to the 196 * top of the union stack and is needed by 197 * programs which plan to fchdir to a descriptor 198 * which has also been read -- see fts.c. 199 */ 200 if (flags & DTF_REWIND) { 201 if ((fd2 = _open(name, O_RDONLY | O_DIRECTORY)) == -1) { 202 saved_errno = errno; 203 free(buf); 204 free(dirp); 205 errno = saved_errno; 206 return (NULL); 207 } 208 (void)_dup2(fd2, fd); 209 _close(fd2); 210 } 211 212 /* 213 * There is now a buffer full of (possibly) duplicate 214 * names. 215 */ 216 dirp->dd_buf = buf; 217 218 /* 219 * Go round this loop twice... 220 * 221 * Scan through the buffer, counting entries. 222 * On the second pass, save pointers to each one. 223 * Then sort the pointers and remove duplicate names. 224 */ 225 for (dpv = 0;;) { 226 n = 0; 227 ddptr = buf; 228 while (ddptr < ddeptr) { 229 struct dirent *dp; 230 231 dp = (struct dirent *) ddptr; 232 if ((long)dp & 03L) 233 break; 234 if ((dp->d_reclen <= 0) || 235 (dp->d_reclen > (ddeptr + 1 - ddptr))) 236 break; 237 ddptr += dp->d_reclen; 238 if (dp->d_fileno) { 239 if (dpv) 240 dpv[n] = dp; 241 n++; 242 } 243 } 244 245 if (dpv) { 246 struct dirent *xp; 247 248 /* 249 * This sort must be stable. 250 */ 251 mergesort(dpv, n, sizeof(*dpv), 252 opendir_compar); 253 254 dpv[n] = NULL; 255 xp = NULL; 256 257 /* 258 * Scan through the buffer in sort order, 259 * zapping the inode number of any 260 * duplicate names. 261 */ 262 for (n = 0; dpv[n]; n++) { 263 struct dirent *dp = dpv[n]; 264 265 if ((xp == NULL) || 266 strcmp(dp->d_name, xp->d_name)) { 267 xp = dp; 268 } else { 269 dp->d_fileno = 0; 270 } 271 if (dp->d_type == DT_WHT && 272 (flags & DTF_HIDEW)) 273 dp->d_fileno = 0; 274 } 275 276 free(dpv); 277 break; 278 } else { 279 dpv = malloc((n+1) * sizeof(struct dirent *)); 280 if (dpv == NULL) 281 break; 282 } 283 } 284 285 dirp->dd_len = len; 286 dirp->dd_size = ddptr - dirp->dd_buf; 287 } else { 288 dirp->dd_len = incr; 289 dirp->dd_size = 0; 290 dirp->dd_buf = malloc(dirp->dd_len); 291 if (dirp->dd_buf == NULL) 292 goto fail; 293 dirp->dd_seek = 0; 294 flags &= ~DTF_REWIND; 295 } 296 297 dirp->dd_loc = 0; 298 dirp->dd_fd = fd; 299 dirp->dd_flags = flags; 300 dirp->dd_lock = NULL; 301 302 /* 303 * Set up seek point for rewinddir. 304 */ 305 dirp->dd_rewind = telldir(dirp); 306 307 return (dirp); 308 309 fail: 310 saved_errno = errno; 311 free(dirp); 312 errno = saved_errno; 313 return (NULL); 314 } 315