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/*
* Copyright (c) 1983, 1993, 1994
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $Id$
*/
#include <sys/param.h>
#include <sys/mount.h>
#include <dirent.h>
#include <fcntl.h>
#include <stdlib.h>
#include <unistd.h>
/*
* open a directory.
*/
DIR *
opendir(name)
const char *name;
{
DIR *dirp;
int fd;
int incr;
struct statfs sfb;
if ((fd = open(name, 0)) == -1)
return (NULL);
if (fcntl(fd, F_SETFD, FD_CLOEXEC) == -1 ||
(dirp = (DIR *)malloc(sizeof(DIR))) == NULL) {
close(fd);
return (NULL);
}
/*
* If CLBYTES is an exact multiple of DIRBLKSIZ, use a CLBYTES
* buffer that it cluster boundary aligned.
* Hopefully this can be a big win someday by allowing page
* trades trade to user space to be done by getdirentries()
*/
if ((CLBYTES % DIRBLKSIZ) == 0)
incr = CLBYTES;
else
incr = DIRBLKSIZ;
#ifdef MOUNT_UNION
/*
* Determine whether this directory is the top of a union stack.
*/
if (fstatfs(fd, &sfb) < 0) {
free(dirp);
close(fd);
return (NULL);
}
if (sfb.f_type == MOUNT_UNION) {
int len = 0;
int space = 0;
char *buf = 0;
char *ddptr = 0;
int n;
struct dirent **dpv;
/*
* The strategy here is to read all the directory
* entries into a buffer, sort the buffer, and
* remove duplicate entries by setting the inode
* number to zero.
*/
/*
* Fixup dd_loc to be non-zero to fake out readdir
*/
dirp->dd_loc = sizeof(void *);
do {
/*
* Always make at least DIRBLKSIZ bytes
* available to getdirentries
*/
if (space < DIRBLKSIZ) {
space += incr;
len += incr;
buf = realloc(buf, len);
if (buf == NULL) {
free(dirp);
close(fd);
return (NULL);
}
ddptr = buf + (len - space) + dirp->dd_loc;
}
n = getdirentries(fd, ddptr, space, &dirp->dd_seek);
if (n > 0) {
ddptr += n;
space -= n;
}
} while (n > 0);
/*
* There is now a buffer full of (possibly) duplicate
* names.
*/
dirp->dd_buf = buf;
/*
* Go round this loop twice...
*
* Scan through the buffer, counting entries.
* On the second pass, save pointers to each one.
* Then sort the pointers and remove duplicate names.
*/
for (dpv = 0;;) {
n = 0;
ddptr = buf + dirp->dd_loc;
while (ddptr < buf + len) {
struct dirent *dp;
dp = (struct dirent *) ddptr;
if ((int)dp & 03)
break;
if ((dp->d_reclen <= 0) ||
(dp->d_reclen > (buf + len + 1 - ddptr)))
break;
ddptr += dp->d_reclen;
if (dp->d_fileno) {
if (dpv)
dpv[n] = dp;
n++;
}
}
if (dpv) {
struct dirent *xp;
/*
* If and when whiteouts happen,
* this sort would need to be stable.
*/
heapsort(dpv, n, sizeof(*dpv), alphasort);
dpv[n] = NULL;
xp = NULL;
/*
* Scan through the buffer in sort order,
* zapping the inode number of any
* duplicate names.
*/
for (n = 0; dpv[n]; n++) {
struct dirent *dp = dpv[n];
if ((xp == NULL) ||
strcmp(dp->d_name, xp->d_name))
xp = dp;
else
dp->d_fileno = 0;
}
free(dpv);
break;
} else {
dpv = malloc((n+1) * sizeof(struct dirent *));
if (dpv == NULL)
break;
}
}
dirp->dd_len = len;
dirp->dd_size = ddptr - dirp->dd_buf;
} else
#endif /* MOUNT_UNION */
{
dirp->dd_len = incr;
dirp->dd_buf = malloc(dirp->dd_len);
if (dirp->dd_buf == NULL) {
free(dirp);
close (fd);
return (NULL);
}
dirp->dd_seek = 0;
dirp->dd_loc = 0;
}
dirp->dd_fd = fd;
/*
* Set up seek point for rewinddir.
*/
dirp->dd_rewind = telldir(dirp);
return (dirp);
}
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