/*-
 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
 *
 * Copyright (c) 2001-2002 Chris D. Faulhaber
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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 0
__FBSDID("$FreeBSD: head/lib/libc/posix1e/acl_delete_entry.c 326193 2017-11-25 17:12:48Z pfg $");
#else
__RCSID("$NetBSD: acl_delete_entry.c,v 1.1 2020/05/16 18:31:47 christos Exp $");
#endif

#include "namespace.h"
#include <sys/types.h>
#include <sys/acl.h>
#include <errno.h>
#include <string.h>
#include <stdio.h>

#include "acl_support.h"

static int
_entry_matches(const acl_entry_t a, const acl_entry_t b)
{
        /*
         * There is a semantical difference here between NFSv4 and POSIX
         * draft ACLs.  In POSIX, there may be only one entry for the particular
         * user or group.  In NFSv4 ACL, there may be any number of them.  We're
         * trying to be more specific here in that case.
         */
        switch (_entry_brand(a)) {
        case ACL_BRAND_NFS4:
                if (a->ae_tag != b->ae_tag || a->ae_entry_type != b->ae_entry_type)
                        return (0);

                /* If ae_ids matter, compare them as well. */
                if (a->ae_tag == ACL_USER || a->ae_tag == ACL_GROUP) {
                        if (a->ae_id != b->ae_id)
                                return (0);
                }

                return (1);

        default:
                if ((a->ae_tag == b->ae_tag) && (a->ae_id == b->ae_id))
                        return (1);
        }

        return (0);
}

/*
 * acl_delete_entry() (23.4.9): remove the ACL entry indicated by entry_d
 * from acl.
 */
int
acl_delete_entry(acl_t acl, acl_entry_t entry_d)
{
        struct acl_entry entry_int;
        size_t i, j;
        int found = 0;

        if (acl == NULL || entry_d == NULL) {
                errno = EINVAL;
                return (-1);
        }

        if (_entry_brand(entry_d) != _acl_brand(acl)) {
                errno = EINVAL;
                return (-1);
        }

        if ((acl->ats_acl.acl_cnt < 1) ||
            (acl->ats_acl.acl_cnt > ACL_MAX_ENTRIES)) {
                errno = EINVAL;
                return (-1);
        }

        /* Use a local copy to prevent deletion of more than this entry */
        entry_int = *entry_d;

        for (i = 0; i < acl->ats_acl.acl_cnt;) {
                if (_entry_matches(&(acl->ats_acl.acl_entry[i]), &entry_int)) {
                        /* ...shift the remaining entries... */
                        for (j = i; j < acl->ats_acl.acl_cnt - 1; ++j)
                                acl->ats_acl.acl_entry[j] =
                                    acl->ats_acl.acl_entry[j+1];
                        /* ...drop the count and zero the unused entry... */
                        acl->ats_acl.acl_cnt--;
                        bzero(&acl->ats_acl.acl_entry[j],
                            sizeof(struct acl_entry));
                        acl->ats_cur_entry = 0;
                        
                        /* Continue with the loop to remove all matching entries. */
                        found = 1;
                } else
                        i++;
        }

        if (found)
                return (0);

        errno = EINVAL;
        return (-1);
}

int
acl_delete_entry_np(acl_t acl, int offset)
{
        struct acl *acl_int;
        size_t i;

        if (acl == NULL) {
                errno = EINVAL;
                return (-1);
        }

        acl_int = &acl->ats_acl;

        if (offset < 0 || (size_t)offset >= acl_int->acl_cnt) {
                errno = EINVAL;
                return (-1);
        }

        if ((acl->ats_acl.acl_cnt < 1) ||
            (acl->ats_acl.acl_cnt > ACL_MAX_ENTRIES)) {
                errno = EINVAL;
                return (-1);
        }

        /* ...shift the remaining entries... */
        for (i = offset; i < acl->ats_acl.acl_cnt - 1; ++i)
                acl->ats_acl.acl_entry[i] =
                    acl->ats_acl.acl_entry[i+1];
        /* ...drop the count and zero the unused entry... */
        acl->ats_acl.acl_cnt--;
        bzero(&acl->ats_acl.acl_entry[i],
            sizeof(struct acl_entry));
        acl->ats_cur_entry = 0;

        return (0);
}