NetBSD/lib/libc/gen/opendir.c
jtc 43fa6fe319 If port provides __weak_alias(), provide an Standard C and POSIX pure
identifier namespace by renaming non standard functions and variables
such that they have a leading underscore.  The library will use those
names internally.  Weak aliases are used to provide the original names
to the API.

This is only the first part of this change.  It is most of the functions
which are implemented in C for all NetBSD ports.  Subsequent changes are
to add the same support to the remaining C files, to assembly files, and
to the automagically generated assembly source used for system calls.
When all of the above is done, ports with weak alias support should add
a definition for __weak_alias to <sys/cdefs.h>.
1997-07-21 14:06:24 +00:00

278 lines
6.5 KiB
C

/* $NetBSD: opendir.c,v 1.14 1997/07/21 14:07:22 jtc Exp $ */
/*
* Copyright (c) 1983, 1993
* 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.
*/
#include <sys/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
#if 0
static char sccsid[] = "@(#)opendir.c 8.7 (Berkeley) 12/10/94";
#else
__RCSID("$NetBSD: opendir.c,v 1.14 1997/07/21 14:07:22 jtc Exp $");
#endif
#endif /* LIBC_SCCS and not lint */
#include "namespace.h"
#include <sys/param.h>
#include <sys/mount.h>
#include <sys/stat.h>
#include <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#ifdef __weak_alias
__weak_alias(opendir,_opendir);
#endif
/*
* Open a directory.
*/
DIR *
opendir(name)
const char *name;
{
return (__opendir2(name, DTF_HIDEW|DTF_NODUP));
}
DIR *
__opendir2(name, flags)
const char *name;
int flags;
{
DIR *dirp;
int fd;
struct stat sb;
int pagesz;
int incr;
int unionstack;
if ((fd = open(name, O_RDONLY | O_NONBLOCK)) == -1)
return (NULL);
if (fstat(fd, &sb) || !S_ISDIR(sb.st_mode)) {
errno = ENOTDIR;
close(fd);
return (NULL);
}
if (fcntl(fd, F_SETFD, FD_CLOEXEC) == -1 ||
(dirp = (DIR *)malloc(sizeof(DIR))) == NULL) {
close(fd);
return (NULL);
}
/*
* If the machine's page size is an exact multiple of DIRBLKSIZ,
* use a buffer that is cluster boundary aligned.
* Hopefully this can be a big win someday by allowing page trades
* to user space to be done by getdirentries()
*/
if (((pagesz = getpagesize()) % DIRBLKSIZ) == 0)
incr = pagesz;
else
incr = DIRBLKSIZ;
/*
* Determine whether this directory is the top of a union stack.
*/
if (flags & DTF_NODUP) {
struct statfs sfb;
if (fstatfs(fd, &sfb) < 0) {
free(dirp);
close(fd);
return (NULL);
}
unionstack = !(strncmp(sfb.f_fstypename, MOUNT_UNION,
MFSNAMELEN)) || (sfb.f_flags & MNT_UNION);
} else {
unionstack = 0;
}
if (unionstack) {
int len = 0;
int space = 0;
char *buf = 0;
char *ddptr = 0;
char *ddeptr;
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.
*/
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);
}
n = getdirentries(fd, ddptr, space, &dirp->dd_seek);
if (n > 0) {
ddptr += n;
space -= n;
}
} while (n > 0);
ddeptr = ddptr;
flags |= __DTF_READALL;
/*
* Re-open the directory.
* This has the effect of rewinding back to the
* top of the union stack and is needed by
* programs which plan to fchdir to a descriptor
* which has also been read -- see fts.c.
*/
if (flags & DTF_REWIND) {
(void) close(fd);
if ((fd = open(name, O_RDONLY)) == -1) {
free(buf);
free(dirp);
return (NULL);
}
}
/*
* 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;;) {
for (n = 0, ddptr = buf; ddptr < ddeptr;) {
struct dirent *dp;
dp = (struct dirent *) ddptr;
if ((long)dp & 03)
break;
if ((dp->d_reclen <= 0) ||
(dp->d_reclen > (ddeptr + 1 - ddptr)))
break;
ddptr += dp->d_reclen;
if (dp->d_fileno) {
if (dpv)
dpv[n] = dp;
n++;
}
}
if (dpv) {
struct dirent *xp;
/*
* This sort must be stable.
*/
mergesort(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;
if (dp->d_type == DT_WHT &&
(flags & DTF_HIDEW))
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 {
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;
flags &= ~DTF_REWIND;
}
dirp->dd_loc = 0;
dirp->dd_fd = fd;
dirp->dd_flags = flags;
/*
* Set up seek point for rewinddir.
*/
dirp->dd_rewind = telldir(dirp);
return (dirp);
}