/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2017-2019 The DragonFly Project
 * Copyright (c) 2017-2019 Tomohiro Kusumi <tkusumi@netbsd.org>
 * All rights reserved.
 *
 * This software was developed by Edward Tomasz Napierala under sponsorship
 * from the FreeBSD Foundation.
 *
 * 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 AUTHORS 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 AUTHORS 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 <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <string.h>
#include <err.h>
#include <assert.h>

#include <sys/types.h>

#include "hammer2_disk.h"

#include "fstyp.h"

static hammer2_volume_data_t*
read_voldata(FILE *fp)
{
        hammer2_volume_data_t *voldata;

        voldata = read_buf(fp, 0, sizeof(*voldata));
        if (voldata == NULL)
                err(1, "failed to read volume data");

        return (voldata);
}

static int
test_voldata(const hammer2_volume_data_t *voldata)
{
        if (voldata->magic != HAMMER2_VOLUME_ID_HBO &&
            voldata->magic != HAMMER2_VOLUME_ID_ABO)
                return (1);

        return (0);
}

static hammer2_media_data_t*
read_media(FILE *fp, const hammer2_blockref_t *bref, size_t *media_bytes)
{
        hammer2_media_data_t *media;
        hammer2_off_t io_off, io_base;
        size_t bytes, io_bytes, boff;

        bytes = (bref->data_off & HAMMER2_OFF_MASK_RADIX);
        if (bytes)
                bytes = (size_t)1 << bytes;
        *media_bytes = bytes;

        if (!bytes) {
                warnx("blockref has no data");
                return (NULL);
        }

        io_off = bref->data_off & ~HAMMER2_OFF_MASK_RADIX;
        io_base = io_off & ~(hammer2_off_t)(HAMMER2_MINIOSIZE - 1);
        boff = io_off - io_base;

        io_bytes = HAMMER2_MINIOSIZE;
        while (io_bytes + boff < bytes)
                io_bytes <<= 1;

        if (io_bytes > sizeof(hammer2_media_data_t)) {
                warnx("invalid I/O bytes");
                return (NULL);
        }

        if (fseek(fp, io_base, SEEK_SET) == -1) {
                warnx("failed to seek media");
                return (NULL);
        }
        media = read_buf(fp, io_base, io_bytes);
        if (media == NULL) {
                warnx("failed to read media");
                return (NULL);
        }
        if (boff)
                memcpy(media, (char *)media + boff, bytes);

        return (media);
}

static int
find_pfs(FILE *fp, const hammer2_blockref_t *bref, const char *pfs, bool *res)
{
        hammer2_media_data_t *media;
        hammer2_inode_data_t ipdata;
        hammer2_blockref_t *bscan;
        size_t bytes;
        int i, bcount;

        media = read_media(fp, bref, &bytes);
        if (media == NULL)
                return (-1);

        switch (bref->type) {
        case HAMMER2_BREF_TYPE_INODE:
                ipdata = media->ipdata;
                if (ipdata.meta.pfs_type == HAMMER2_PFSTYPE_SUPROOT) {
                        bscan = &ipdata.u.blockset.blockref[0];
                        bcount = HAMMER2_SET_COUNT;
                } else {
                        bscan = NULL;
                        bcount = 0;
                        if (ipdata.meta.op_flags & HAMMER2_OPFLAG_PFSROOT) {
                                if (memchr(ipdata.filename, 0,
                                    sizeof(ipdata.filename))) {
                                        if (!strcmp(
                                            (const char*)ipdata.filename, pfs))
                                                *res = true;
                                } else {
                                        if (strlen(pfs) > 0 &&
                                            !memcmp(ipdata.filename, pfs,
                                            strlen(pfs)))
                                                *res = true;
                                }
                        } else
                                assert(0);
                }
                break;
        case HAMMER2_BREF_TYPE_INDIRECT:
                bscan = &media->npdata[0];
                bcount = bytes / sizeof(hammer2_blockref_t);
                break;
        default:
                bscan = NULL;
                bcount = 0;
                break;
        }

        for (i = 0; i < bcount; ++i) {
                if (bscan[i].type != HAMMER2_BREF_TYPE_EMPTY) {
                        if (find_pfs(fp, &bscan[i], pfs, res) == -1) {
                                free(media);
                                return (-1);
                        }
                }
        }
        free(media);

        return (0);
}

static char*
extract_device_name(const char *devpath)
{
        char *p, *head;

        if (!devpath)
                return NULL;

        p = strdup(devpath);
        head = p;

        p = strchr(p, '@');
        if (p)
                *p = 0;

        p = strrchr(head, '/');
        if (p) {
                p++;
                if (*p == 0) {
                        free(head);
                        return NULL;
                }
                p = strdup(p);
                free(head);
                return p;
        }

        return head;
}

static int
read_label(FILE *fp, char *label, size_t size)
{
        hammer2_blockref_t broot, best, *bref;
        hammer2_media_data_t *vols[HAMMER2_NUM_VOLHDRS], *media;
        size_t bytes;
        bool res = false;
        int i, best_i, error = 1;
        const char *pfs;
        char *devname;

        best_i = -1;
        memset(&best, 0, sizeof(best));

        for (i = 0; i < HAMMER2_NUM_VOLHDRS; i++) {
                memset(&broot, 0, sizeof(broot));
                broot.type = HAMMER2_BREF_TYPE_VOLUME;
                broot.data_off = (i * HAMMER2_ZONE_BYTES64) | HAMMER2_PBUFRADIX;
                vols[i] = read_buf(fp, broot.data_off & ~HAMMER2_OFF_MASK_RADIX,
                    sizeof(*vols[i]));
                if (vols[i] == NULL)
                        errx(1, "failed to read volume header");
                broot.mirror_tid = vols[i]->voldata.mirror_tid;
                if (best_i < 0 || best.mirror_tid < broot.mirror_tid) {
                        best_i = i;
                        best = broot;
                }
        }

        bref = &vols[best_i]->voldata.sroot_blockset.blockref[0];
        if (bref->type != HAMMER2_BREF_TYPE_INODE) {
                warnx("blockref type is not inode");
                goto fail;
        }

        media = read_media(fp, bref, &bytes);
        if (media == NULL) {
                goto fail;
        }

        pfs = "";
        devname = extract_device_name(NULL);
        assert(!devname); /* Currently always NULL in FreeBSD. */

        /* Add device name to help support multiple autofs -media mounts. */
        if (find_pfs(fp, bref, pfs, &res) == 0 && res) {
                if (devname)
                        snprintf(label, size, "%s_%s", pfs, devname);
                else
                        strlcpy(label, pfs, size);
        } else {
                memset(label, 0, size);
                memcpy(label, media->ipdata.filename,
                    sizeof(media->ipdata.filename));
                if (devname) {
                        strlcat(label, "_", size);
                        strlcat(label, devname, size);
                }
        }
        if (devname)
                free(devname);
        free(media);
        error = 0;
fail:
        for (i = 0; i < HAMMER2_NUM_VOLHDRS; i++)
                free(vols[i]);

        return (error);
}

int
fstyp_hammer2(FILE *fp, char *label, size_t size)
{
        hammer2_volume_data_t *voldata;
        int error = 1;

        voldata = read_voldata(fp);
        if (test_voldata(voldata))
                goto fail;

        error = read_label(fp, label, size);
fail:
        free(voldata);
        return (error);
}