minix/lib/libc/gen/scandir.c

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/* $NetBSD: scandir.c,v 1.27 2012/03/13 21:13:36 christos 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. 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[] = "@(#)scandir.c 8.3 (Berkeley) 1/2/94";
#else
__RCSID("$NetBSD: scandir.c,v 1.27 2012/03/13 21:13:36 christos Exp $");
#endif
#endif /* LIBC_SCCS and not lint */
/*
* Scan the directory dirname calling selectfn to make a list of selected
* directory entries then sort using qsort and compare routine dcomp.
* Returns the number of entries and a pointer to a list of pointers to
* struct dirent (through namelist). Returns -1 if there were any errors.
*/
#include "namespace.h"
#include <sys/types.h>
#include <sys/stat.h>
#include <assert.h>
#include <errno.h>
#include <dirent.h>
#include <stdlib.h>
#include <string.h>
/*
* Compute an estimate of the number of entries in a directory based on
* the file size. Returns the estimated number of entries or 0 on failure.
*/
static size_t
dirsize(int fd, size_t olen)
{
struct stat stb;
size_t nlen;
if (fstat(fd, &stb) == -1)
return 0;
/*
* Estimate the array size by taking the size of the directory file
* and dividing it by a multiple of the minimum size entry.
*/
nlen = (size_t)(stb.st_size / _DIRENT_MINSIZE((struct dirent *)0));
/*
* If the size turns up 0, switch to an alternate strategy and use the
* file size as the number of entries like ZFS returns. If that turns
* out to be 0 too return a minimum of 10 entries, plus the old length.
*/
if (nlen == 0)
nlen = (size_t)(stb.st_size ? stb.st_size : 10);
return olen + nlen;
}
int
scandir(const char *dirname, struct dirent ***namelist,
int (*selectfn)(const struct dirent *),
int (*dcomp)(const void *, const void *))
{
struct dirent *d, *p, **names, **newnames;
size_t nitems, arraysz;
DIR *dirp;
_DIAGASSERT(dirname != NULL);
_DIAGASSERT(namelist != NULL);
if ((dirp = opendir(dirname)) == NULL)
return -1;
if ((arraysz = dirsize(dirp->dd_fd, 0)) == 0)
goto bad;
names = malloc(arraysz * sizeof(*names));
if (names == NULL)
goto bad;
nitems = 0;
while ((d = readdir(dirp)) != NULL) {
if (selectfn != NULL && !(*selectfn)(d))
continue; /* just selected names */
/*
* Check to make sure the array has space left and
* realloc the maximum size.
*/
if (nitems >= arraysz) {
if ((arraysz = dirsize(dirp->dd_fd, arraysz)) == 0)
goto bad2;
newnames = realloc(names, arraysz * sizeof(*names));
if (newnames == NULL)
goto bad2;
names = newnames;
}
/*
* Make a minimum size copy of the data
*/
p = malloc((size_t)_DIRENT_SIZE(d));
if (p == NULL)
goto bad2;
p->d_fileno = d->d_fileno;
p->d_reclen = d->d_reclen;
p->d_type = d->d_type;
p->d_namlen = d->d_namlen;
(void)memmove(p->d_name, d->d_name, (size_t)(p->d_namlen + 1));
names[nitems++] = p;
}
(void)closedir(dirp);
if (nitems && dcomp != NULL)
qsort(names, nitems, sizeof(*names), dcomp);
*namelist = names;
_DIAGASSERT(__type_fit(int, nitems));
return (int)nitems;
bad2:
while (nitems-- > 0)
free(names[nitems]);
free(names);
bad:
(void)closedir(dirp);
return -1;
}