2 * Copyright (c) 1983, 1993
3 * The Regents of the University of California. All rights reserved.
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15 * This product includes software developed by the University of
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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 $
34 * $DragonFly: src/lib/libc/gen/opendir.c,v 1.2 2003/06/17 04:26:42 dillon Exp $
36 * @(#)opendir.c 8.8 (Berkeley) 5/1/95
39 #include <sys/param.h>
40 #include <sys/mount.h>
57 return (__opendir2(name, DTF_HIDEW|DTF_NODUP));
61 __opendir2(name, flags)
73 * stat() before open() because opening of special files may be
74 * harmful. fstat() after open because the file may have changed.
76 if (stat(name, &statb) != 0)
78 if (!S_ISDIR(statb.st_mode)) {
82 if ((fd = _open(name, O_RDONLY | O_NONBLOCK)) == -1)
85 if (fstat(fd, &statb) != 0)
87 if (!S_ISDIR(statb.st_mode)) {
91 if (_fcntl(fd, F_SETFD, FD_CLOEXEC) == -1 ||
92 (dirp = malloc(sizeof(DIR))) == NULL)
96 * Use the system page size if that is a multiple of DIRBLKSIZ.
97 * Hopefully this can be a big win someday by allowing page
98 * trades to user space to be done by getdirentries().
100 incr = getpagesize();
101 if ((incr % DIRBLKSIZ) != 0)
105 * Determine whether this directory is the top of a union stack.
107 if (flags & DTF_NODUP) {
110 if (fstatfs(fd, &sfb) < 0)
112 unionstack = !strcmp(sfb.f_fstypename, "union")
113 || (sfb.f_flags & MNT_UNION);
128 * The strategy here is to read all the directory
129 * entries into a buffer, sort the buffer, and
130 * remove duplicate entries by setting the inode
136 * Always make at least DIRBLKSIZ bytes
137 * available to getdirentries
139 if (space < DIRBLKSIZ) {
142 buf = reallocf(buf, len);
145 ddptr = buf + (len - space);
148 n = getdirentries(fd, ddptr, space, &dirp->dd_seek);
156 flags |= __DTF_READALL;
159 * Re-open the directory.
160 * This has the effect of rewinding back to the
161 * top of the union stack and is needed by
162 * programs which plan to fchdir to a descriptor
163 * which has also been read -- see fts.c.
165 if (flags & DTF_REWIND) {
167 if ((fd = _open(name, O_RDONLY)) == -1) {
177 * There is now a buffer full of (possibly) duplicate
183 * Go round this loop twice...
185 * Scan through the buffer, counting entries.
186 * On the second pass, save pointers to each one.
187 * Then sort the pointers and remove duplicate names.
192 while (ddptr < ddeptr) {
195 dp = (struct dirent *) ddptr;
198 if ((dp->d_reclen <= 0) ||
199 (dp->d_reclen > (ddeptr + 1 - ddptr)))
201 ddptr += dp->d_reclen;
213 * This sort must be stable.
215 mergesort(dpv, n, sizeof(*dpv), alphasort);
221 * Scan through the buffer in sort order,
222 * zapping the inode number of any
225 for (n = 0; dpv[n]; n++) {
226 struct dirent *dp = dpv[n];
229 strcmp(dp->d_name, xp->d_name)) {
234 if (dp->d_type == DT_WHT &&
242 dpv = malloc((n+1) * sizeof(struct dirent *));
249 dirp->dd_size = ddptr - dirp->dd_buf;
252 dirp->dd_buf = malloc(dirp->dd_len);
253 if (dirp->dd_buf == NULL)
256 flags &= ~DTF_REWIND;
261 dirp->dd_flags = flags;
264 * Set up seek point for rewinddir.
266 dirp->dd_rewind = telldir(dirp);