/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * 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.
 */

/*
 * 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 <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "un-namespace.h"

#ifdef  I_AM_SCANDIR_B
#include "block_abi.h"
#define SELECT(x)       CALL_BLOCK(select, x)
#ifndef __BLOCKS__
void qsort_b(void *, size_t, size_t, void *);
#endif
#else
#define SELECT(x)       select(x)
#endif

#ifdef I_AM_SCANDIR_B
typedef DECLARE_BLOCK(int, select_block, const struct dirent *);
typedef DECLARE_BLOCK(int, dcomp_block, const struct dirent **,
    const struct dirent **);
#else
static int scandir_thunk_cmp(const void *p1, const void *p2, void *thunk);
#endif

static int
#ifdef I_AM_SCANDIR_B
scandir_dirp_b(DIR *dirp, struct dirent ***namelist, select_block select,
    dcomp_block dcomp)
#else
scandir_dirp(DIR *dirp, struct dirent ***namelist,
    int (*select)(const struct dirent *),
    int (*dcomp)(const struct dirent **, const struct dirent **))
#endif
{
        struct dirent *d, *p = NULL, **names = NULL, **names2;
        size_t arraysz = 32, numitems = 0;
        int serrno;

        names = malloc(arraysz * sizeof(*names));
        if (names == NULL)
                return (-1);

        while (errno = 0, (d = readdir(dirp)) != NULL) {
                if (select != NULL && !SELECT(d))
                        continue;       /* just selected names */
                /*
                 * Make a minimum size copy of the data
                 */
                p = malloc(_GENERIC_DIRSIZ(d));
                if (p == NULL)
                        goto fail;
                p->d_fileno = d->d_fileno;
                p->d_type = d->d_type;
                p->d_reclen = d->d_reclen;
                p->d_namlen = d->d_namlen;
                memcpy(p->d_name, d->d_name, p->d_namlen + 1);
                /*
                 * Check to make sure the array has space left and
                 * realloc the maximum size.
                 */
                if (numitems >= arraysz) {
                        arraysz = arraysz * 2;
                        names2 = reallocarray(names, arraysz, sizeof(*names));
                        if (names2 == NULL)
                                goto fail;
                        names = names2;
                }
                names[numitems++] = p;
        }
        /*
         * Since we can't simultaneously return both -1 and a count, we
         * must either suppress the error or discard the partial result.
         * The latter seems the lesser of two evils.
         */
        if (errno != 0)
                goto fail;
        if (numitems > 0 && dcomp != NULL) {
#ifdef I_AM_SCANDIR_B
                qsort_b(names, numitems, sizeof(struct dirent *),
                    (void *)dcomp);
#else
                qsort_r(names, numitems, sizeof(struct dirent *),
                    scandir_thunk_cmp, &dcomp);
#endif
        }
        *namelist = names;
        return (numitems);

fail:
        serrno = errno;
        if (numitems == 0 || names[numitems - 1] != p)
                free(p);
        while (numitems > 0)
                free(names[--numitems]);
        free(names);
        errno = serrno;
        return (-1);
}

int
#ifdef I_AM_SCANDIR_B
scandir_b(const char *dirname, struct dirent ***namelist, select_block select,
    dcomp_block dcomp)
#else
scandir(const char *dirname, struct dirent ***namelist,
    int (*select)(const struct dirent *),
    int (*dcomp)(const struct dirent **, const struct dirent **))
#endif
{
        DIR *dirp;
        int ret, serrno;

        dirp = opendir(dirname);
        if (dirp == NULL)
                return (-1);
        ret =
#ifdef I_AM_SCANDIR_B
            scandir_dirp_b
#else
            scandir_dirp
#endif
            (dirp, namelist, select, dcomp);
        serrno = errno;
        closedir(dirp);
        errno = serrno;
        return (ret);
}

int
#ifdef I_AM_SCANDIR_B
fdscandir_b(int dirfd, struct dirent ***namelist, select_block select,
    dcomp_block dcomp)
#else
fdscandir(int dirfd, struct dirent ***namelist,
    int (*select)(const struct dirent *),
    int (*dcomp)(const struct dirent **, const struct dirent **))
#endif
{
        DIR *dirp;
        int ret, serrno;

        dirp = fdopendir(dirfd);
        if (dirp == NULL)
                return (-1);
        ret =
#ifdef I_AM_SCANDIR_B
            scandir_dirp_b
#else
            scandir_dirp
#endif
            (dirp, namelist, select, dcomp);
        serrno = errno;
        fdclosedir(dirp);
        errno = serrno;
        return (ret);
}

int
#ifdef I_AM_SCANDIR_B
scandirat_b(int dirfd, const char *dirname, struct dirent ***namelist,
    select_block select, dcomp_block dcomp)
#else
scandirat(int dirfd, const char *dirname, struct dirent ***namelist,
    int (*select)(const struct dirent *),
    int (*dcomp)(const struct dirent **, const struct dirent **))
#endif
{
        int fd, ret, serrno;

        fd = _openat(dirfd, dirname, O_RDONLY | O_DIRECTORY | O_CLOEXEC);
        if (fd == -1)
                return (-1);
        ret =
#ifdef I_AM_SCANDIR_B
            fdscandir_b
#else
            fdscandir
#endif
            (fd, namelist, select, dcomp);
        serrno = errno;
        _close(fd);
        errno = serrno;
        return (ret);
}

#ifndef I_AM_SCANDIR_B
/*
 * Alphabetic order comparison routine for those who want it.
 * POSIX 2008 requires that alphasort() uses strcoll().
 */
int
alphasort(const struct dirent **d1, const struct dirent **d2)
{
        return (strcoll((*d1)->d_name, (*d2)->d_name));
}

int
versionsort(const struct dirent **d1, const struct dirent **d2)
{
        return (strverscmp((*d1)->d_name, (*d2)->d_name));
}

static int
scandir_thunk_cmp(const void *p1, const void *p2, void *thunk)
{
        int (*dc)(const struct dirent **, const struct dirent **);

        dc = *(int (**)(const struct dirent **, const struct dirent **))thunk;
        return (dc((const struct dirent **)p1, (const struct dirent **)p2));
}
#endif