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) 31static 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 <pthread.h> 48#include "un-namespace.h" 49 50#include "telldir.h" 51 52static DIR * __opendir_common(int, const char *, int); 53 54/* 55 * Open a directory. 56 */ 57DIR * 58opendir(const char *name) 59{ 60 61 return (__opendir2(name, DTF_HIDEW|DTF_NODUP)); 62} 63 64/* 65 * Open a directory with existing file descriptor. 66 */ 67DIR * 68fdopendir(int fd) 69{ 70 struct stat statb; 71 72 /* Check that fd is associated with a directory. */ 73 if (_fstat(fd, &statb) != 0) 74 return (NULL); 75 if (!S_ISDIR(statb.st_mode)) { 76 errno = ENOTDIR; 77 return (NULL); 78 } 79 if (_fcntl(fd, F_SETFD, FD_CLOEXEC) == -1) 80 return (NULL); 81 return (__opendir_common(fd, NULL, DTF_HIDEW|DTF_NODUP)); 82} 83 84DIR * 85__opendir2(const char *name, int flags) 86{ 87 int fd; 88 89 if ((fd = _open(name, 90 O_RDONLY | O_NONBLOCK | O_DIRECTORY | O_CLOEXEC)) == -1) 91 return (NULL); 92 93 return __opendir_common(fd, name, flags); 94} 95 96static int 97opendir_compar(const void *p1, const void *p2) 98{ 99 100 return (strcmp((*(const struct dirent **)p1)->d_name, 101 (*(const struct dirent **)p2)->d_name)); 102} 103 104/* 105 * Common routine for opendir(3), __opendir2(3) and fdopendir(3). 106 */ 107static DIR * 108__opendir_common(int fd, const char *name, int flags) 109{ 110 DIR *dirp; 111 int incr; 112 int saved_errno; 113 int unionstack; 114 115 if ((dirp = malloc(sizeof(DIR) + sizeof(struct _telldir))) == NULL) 116 return (NULL); 117 118 dirp->dd_td = (struct _telldir *)((char *)dirp + sizeof(DIR)); 119 LIST_INIT(&dirp->dd_td->td_locq); 120 dirp->dd_td->td_loccnt = 0; 121 122 /* 123 * Use the system page size if that is a multiple of DIRBLKSIZ. 124 * Hopefully this can be a big win someday by allowing page 125 * trades to user space to be done by _getdirentries(). 126 */ 127 incr = getpagesize(); 128 if ((incr % DIRBLKSIZ) != 0) 129 incr = DIRBLKSIZ; 130 131 /* 132 * Determine whether this directory is the top of a union stack. 133 */ 134 if (flags & DTF_NODUP) { 135 struct statfs sfb; 136 137 if (_fstatfs(fd, &sfb) < 0) 138 goto fail; 139 unionstack = !strcmp(sfb.f_fstypename, "unionfs") 140 || (sfb.f_flags & MNT_UNION); 141 } else { 142 unionstack = 0; 143 } 144 145 if (unionstack) { 146 int len = 0; 147 int space = 0; 148 char *buf = 0; 149 char *ddptr = 0; 150 char *ddeptr; 151 int n; 152 struct dirent **dpv; 153 154 /* 155 * The strategy here is to read all the directory 156 * entries into a buffer, sort the buffer, and 157 * remove duplicate entries by setting the inode 158 * number to zero. 159 */ 160 161 do { 162 /* 163 * Always make at least DIRBLKSIZ bytes 164 * available to _getdirentries 165 */ 166 if (space < DIRBLKSIZ) { 167 space += incr; 168 len += incr; 169 buf = reallocf(buf, len); 170 if (buf == NULL) 171 goto fail; 172 ddptr = buf + (len - space); 173 } 174 175#if __DARWIN_64_BIT_INO_T 176 n = (int)__getdirentries64(fd, ddptr, space, &dirp->dd_td->seekoff); 177#else /* !__DARWIN_64_BIT_INO_T */ 178 n = _getdirentries(fd, ddptr, space, &dirp->dd_seek); 179#endif /* __DARWIN_64_BIT_INO_T */ 180 if (n > 0) { 181 ddptr += n; 182 space -= n; 183 } 184 } while (n > 0); 185 186 ddeptr = ddptr; 187 flags |= __DTF_READALL; 188 189 /* 190 * Re-open the directory. 191 * This has the effect of rewinding back to the 192 * top of the union stack and is needed by 193 * programs which plan to fchdir to a descriptor 194 * which has also been read -- see fts.c. 195 */ 196 if (flags & DTF_REWIND) { 197 (void)_close(fd); 198 if ((fd = _open(name, O_RDONLY | O_DIRECTORY)) == -1) { 199 saved_errno = errno; 200 free(buf); 201 free(dirp); 202 errno = saved_errno; 203 return (NULL); 204 } 205 } 206 207 /* 208 * There is now a buffer full of (possibly) duplicate 209 * names. 210 */ 211 dirp->dd_buf = buf; 212 213 /* 214 * Go round this loop twice... 215 * 216 * Scan through the buffer, counting entries. 217 * On the second pass, save pointers to each one. 218 * Then sort the pointers and remove duplicate names. 219 */ 220 for (dpv = 0;;) { 221 n = 0; 222 ddptr = buf; 223 while (ddptr < ddeptr) { 224 struct dirent *dp; 225 226 dp = (struct dirent *) ddptr; 227 if ((long)dp & 03L) 228 break; 229 if ((dp->d_reclen <= 0) || 230 (dp->d_reclen > (ddeptr + 1 - ddptr))) 231 break; 232 ddptr += dp->d_reclen; 233 if (dp->d_fileno) { 234 if (dpv) 235 dpv[n] = dp; 236 n++; 237 } 238 } 239 240 if (dpv) { 241 struct dirent *xp; 242 243 /* 244 * This sort must be stable. 245 */ 246 mergesort(dpv, n, sizeof(*dpv), 247 opendir_compar); 248 249 dpv[n] = NULL; 250 xp = NULL; 251 252 /* 253 * Scan through the buffer in sort order, 254 * zapping the inode number of any 255 * duplicate names. 256 */ 257 for (n = 0; dpv[n]; n++) { 258 struct dirent *dp = dpv[n]; 259 260 if ((xp == NULL) || 261 strcmp(dp->d_name, xp->d_name)) { 262 xp = dp; 263 } else { 264 dp->d_fileno = 0; 265 } 266 if (dp->d_type == DT_WHT && 267 (flags & DTF_HIDEW)) 268 dp->d_fileno = 0; 269 } 270 271 free(dpv); 272 break; 273 } else { 274 dpv = malloc((n+1) * sizeof(struct dirent *)); 275 if (dpv == NULL) 276 break; 277 } 278 } 279 280 dirp->dd_len = len; 281 dirp->dd_size = ddptr - dirp->dd_buf; 282 } else { 283 dirp->dd_len = incr; 284 dirp->dd_size = 0; 285 dirp->dd_buf = malloc(dirp->dd_len); 286 if (dirp->dd_buf == NULL) 287 goto fail; 288#if __DARWIN_64_BIT_INO_T 289 dirp->dd_td->seekoff = 0; 290#else /* !__DARWIN_64_BIT_INO_T */ 291 dirp->dd_seek = 0; 292#endif /* __DARWIN_64_BIT_INO_T */ 293 flags &= ~DTF_REWIND; 294 } 295 296 dirp->dd_loc = 0; 297 dirp->dd_fd = fd; 298 dirp->dd_flags = flags; 299 dirp->dd_lock = (pthread_mutex_t)PTHREAD_MUTEX_INITIALIZER; 300 301 /* 302 * Set up seek point for rewinddir. 303 */ 304 dirp->dd_rewind = telldir(dirp); 305 306 return (dirp); 307 308fail: 309 saved_errno = errno; 310 free(dirp); 311 (void)_close(fd); 312 errno = saved_errno; 313 return (NULL); 314} 315