2 * Copyright (c) 1983, 1993
3 * The Regents of the University of California. All rights reserved.
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6 * modification, are permitted provided that the following conditions
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13 * 3. All advertising materials mentioning features or use of this software
14 * must display the following acknowledgement:
15 * This product includes software developed by the University of
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17 * 4. Neither the name of the University nor the names of its contributors
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33 * $FreeBSD: src/lib/libc/gen/opendir.c,v 1.10.2.1 2001/06/04 20:59:48 joerg Exp $
36 #if defined(LIBC_SCCS) && !defined(lint)
37 static char sccsid[] = "@(#)opendir.c 8.8 (Berkeley) 5/1/95";
38 #endif /* LIBC_SCCS and not lint */
40 #include <sys/param.h>
41 #include <sys/mount.h>
58 return (__opendir2(name, DTF_HIDEW|DTF_NODUP));
62 __opendir2(name, flags)
74 * stat() before open() because opening of special files may be
75 * harmful. fstat() after open because the file may have changed.
77 if (stat(name, &statb) != 0)
79 if (!S_ISDIR(statb.st_mode)) {
83 if ((fd = _open(name, O_RDONLY | O_NONBLOCK)) == -1)
86 if (fstat(fd, &statb) != 0)
88 if (!S_ISDIR(statb.st_mode)) {
92 if (_fcntl(fd, F_SETFD, FD_CLOEXEC) == -1 ||
93 (dirp = malloc(sizeof(DIR))) == NULL)
97 * Use the system page size if that is a multiple of DIRBLKSIZ.
98 * Hopefully this can be a big win someday by allowing page
99 * trades to user space to be done by getdirentries().
101 incr = getpagesize();
102 if ((incr % DIRBLKSIZ) != 0)
106 * Determine whether this directory is the top of a union stack.
108 if (flags & DTF_NODUP) {
111 if (fstatfs(fd, &sfb) < 0)
113 unionstack = !strcmp(sfb.f_fstypename, "union")
114 || (sfb.f_flags & MNT_UNION);
129 * The strategy here is to read all the directory
130 * entries into a buffer, sort the buffer, and
131 * remove duplicate entries by setting the inode
137 * Always make at least DIRBLKSIZ bytes
138 * available to getdirentries
140 if (space < DIRBLKSIZ) {
143 buf = reallocf(buf, len);
146 ddptr = buf + (len - space);
149 n = getdirentries(fd, ddptr, space, &dirp->dd_seek);
157 flags |= __DTF_READALL;
160 * Re-open the directory.
161 * This has the effect of rewinding back to the
162 * top of the union stack and is needed by
163 * programs which plan to fchdir to a descriptor
164 * which has also been read -- see fts.c.
166 if (flags & DTF_REWIND) {
168 if ((fd = _open(name, O_RDONLY)) == -1) {
178 * There is now a buffer full of (possibly) duplicate
184 * Go round this loop twice...
186 * Scan through the buffer, counting entries.
187 * On the second pass, save pointers to each one.
188 * Then sort the pointers and remove duplicate names.
193 while (ddptr < ddeptr) {
196 dp = (struct dirent *) ddptr;
199 if ((dp->d_reclen <= 0) ||
200 (dp->d_reclen > (ddeptr + 1 - ddptr)))
202 ddptr += dp->d_reclen;
214 * This sort must be stable.
216 mergesort(dpv, n, sizeof(*dpv), alphasort);
222 * Scan through the buffer in sort order,
223 * zapping the inode number of any
226 for (n = 0; dpv[n]; n++) {
227 struct dirent *dp = dpv[n];
230 strcmp(dp->d_name, xp->d_name)) {
235 if (dp->d_type == DT_WHT &&
243 dpv = malloc((n+1) * sizeof(struct dirent *));
250 dirp->dd_size = ddptr - dirp->dd_buf;
253 dirp->dd_buf = malloc(dirp->dd_len);
254 if (dirp->dd_buf == NULL)
257 flags &= ~DTF_REWIND;
262 dirp->dd_flags = flags;
265 * Set up seek point for rewinddir.
267 dirp->dd_rewind = telldir(dirp);