/*
 * 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.
 *
 * $FreeBSD: src/lib/libc/gen/scandir.c,v 1.5.6.1 2001/03/05 09:52:13 obrien Exp $
 *
 * @(#)scandir.c        8.3 (Berkeley) 1/2/94
 */

/*
 * Scan the directory dirname calling select 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 <dirent.h>
#include <limits.h>
#include <stdlib.h>
#include <string.h>
#include "un-namespace.h"

#include "gen_private.h"

int
scandir(const char *dirname, struct dirent ***namelist,
        int (*select)(const struct dirent *),
        int (*dcomp)(const struct dirent **, const struct dirent **))
{
        struct dirent *d, *p, **names = NULL;
        size_t arraysz, nitems = 0;
        struct stat stb;
        DIR *dirp;

        if ((dirp = opendir(dirname)) == NULL)
                return(-1);
        if (_fstat(dirp->dd_fd, &stb) < 0)
                goto fail;

        /*
         * Estimate the array size by taking the size of the directory file
         * and dividing it by a multiple of the minimum size entry.
         * Ensure that the size does fit into memory without overflooding.
         */
        if (stb.st_size / 24 > SIZE_T_MAX)
                goto fail;
        arraysz = stb.st_size / 24;
        names = (struct dirent **)malloc(arraysz * sizeof(struct dirent *));
        if (names == NULL)
                goto fail;

        while ((d = readdir(dirp)) != NULL) {
                if (select != NULL && !(*select)(d))
                        continue;       /* just selected names */
                /*
                 * Make a minimum size copy of the data
                 */
                p = (struct dirent *)malloc(_DIRENT_DIRSIZ(d));
                if (p == NULL)
                        goto fail;
                p->d_ino = d->d_ino;
                p->d_type = d->d_type;
                p->d_namlen = d->d_namlen;
                bcopy(d->d_name, p->d_name, p->d_namlen + 1);
                /*
                 * Check to make sure the array has space left and
                 * realloc the maximum size.
                 */
                if (nitems >= arraysz) {
                        const int inc = 10;     /* increase by this much */
                        struct dirent **names2;

                        names2 = (struct dirent **)realloc((char *)names,
                                (arraysz + inc) * sizeof(struct dirent *));
                        if (names2 == NULL) {
                                free(p);
                                goto fail;
                        }
                        names = names2;
                        arraysz += inc;
                }
                names[nitems++] = p;
        }
        closedir(dirp);
        if (nitems && dcomp != NULL)
                qsort(names, nitems, sizeof(struct dirent *),
                    (int (*)(const void *, const void *))dcomp);
        *namelist = names;
        return(nitems);

fail:
        while (nitems > 0)
                free(names[--nitems]);
        free(names);
        closedir(dirp);
        return -1;
}

/*
 * Alphabetic order comparison routine for those who want it.
 */
int
alphasort(const struct dirent **d1, const struct dirent **d2)
{
        return(strcmp((*d1)->d_name, (*d2)->d_name));
}