/*
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2019 Conrad Meyer <cem@FreeBSD.org>.  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>
#include <assert.h>
#include <err.h>
#include <errno.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "fstyp.h"

/*
 * This really detects the container format, which might be best supported by
 * geom_part or a special GEOM class.
 *
 * https://developer.apple.com/support/downloads/Apple-File-System-Reference.pdf
 */

#define NX_CKSUM_SZ             8

typedef uint64_t nx_oid_t;

typedef uint64_t nx_xid_t;

struct nx_obj {
        uint8_t         o_cksum[NX_CKSUM_SZ];   /* Fletcher 64 */
        nx_oid_t        o_oid;
        nx_xid_t        o_xid;
        uint32_t        o_type;
        uint32_t        o_subtype;
};

/* nx_obj::o_oid */
#define OID_NX_SUPERBLOCK       1

/* nx_obj::o_type: */
#define OBJECT_TYPE_MASK                0x0000ffff
#define OBJECT_TYPE_NX_SUPERBLOCK       0x00000001
#define OBJECT_TYPE_FLAGS_MASK          0xffff0000
#define OBJ_STORAGETYPE_MASK            0xc0000000
#define OBJECT_TYPE_FLAGS_DEFINED_MASK  0xf8000000
#define OBJ_STORAGE_VIRTUAL             0x00000000
#define OBJ_STORAGE_EPHEMERAL           0x80000000
#define OBJ_STORAGE_PHYSICAL            0x40000000
#define OBJ_NOHEADER                    0x20000000
#define OBJ_ENCRYPTED                   0x10000000
#define OBJ_NONPERSISTENT               0x08000000

struct nx_superblock {
        struct nx_obj   nx_o;
        char            nx_magic[4];
        /* ... other stuff that doesn't matter */
};

int
fstyp_apfs(FILE *fp, char *label, size_t size)
{
        struct nx_superblock *csb;
        int retval;

        retval = 1;
        csb = read_buf(fp, 0, sizeof(*csb));
        if (csb == NULL)
                goto fail;

        /* Ideally, checksum the SB here. */
        if (strncmp(csb->nx_magic, "NXSB", 4) != 0 ||
            csb->nx_o.o_oid != OID_NX_SUPERBLOCK ||
            (csb->nx_o.o_type & OBJECT_TYPE_MASK) != OBJECT_TYPE_NX_SUPERBLOCK)
                goto fail;

        retval = 0;

        /* No label support yet. */
        (void)size;
        (void)label;

fail:
        free(csb);
        return (retval);
}