/*
 * Copyright (c) 2007-2016 The DragonFly Project.  All rights reserved.
 *
 * This code is derived from software contributed to The DragonFly Project
 * by Matthew Dillon <dillon@backplane.com>
 *
 * 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 DragonFly Project 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 COPYRIGHT HOLDERS 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
 * COPYRIGHT HOLDERS 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 "hammer.h"

static int hammer_test_offset(const char *msg, hammer_off_t offset);
static void hammer_strip_bigblock(int zone, hammer_off_t offset);
static void hammer_ask_yn(void);

void
hammer_cmd_strip(void)
{
        volume_info_t volume;
        hammer_blockmap_t rootmap;
        hammer_blockmap_layer1_t layer1;
        hammer_blockmap_layer2_t layer2;
        buffer_info_t buffer1 = NULL;
        buffer_info_t buffer2 = NULL;
        hammer_off_t layer1_offset;
        hammer_off_t layer2_offset;
        hammer_off_t phys_offset;
        hammer_off_t block_offset;
        hammer_off_t offset;
        int i, zone = HAMMER_ZONE_FREEMAP_INDEX;

        hammer_ask_yn();

        volume = get_root_volume();
        if (volume == NULL) {
                printf("No root volume found\n");
                goto strip_header;
        }

        rootmap = &volume->ondisk->vol0_blockmap[zone];
        if (!hammer_test_offset("layer1 physical", rootmap->phys_offset))
                goto strip_header;

        for (phys_offset = HAMMER_ZONE_ENCODE(zone, 0);
             phys_offset < HAMMER_ZONE_ENCODE(zone, HAMMER_OFF_LONG_MASK);
             phys_offset += HAMMER_BLOCKMAP_LAYER2) {
                /*
                 * Dive layer 1.
                 */
                layer1_offset = rootmap->phys_offset +
                                HAMMER_BLOCKMAP_LAYER1_OFFSET(phys_offset);
                if (!hammer_test_offset("layer1", layer1_offset))
                        break;
                layer1 = get_buffer_data(layer1_offset, &buffer1, 0);

                if (layer1->phys_offset == HAMMER_BLOCKMAP_UNAVAIL)
                        continue;

                for (block_offset = 0;
                     block_offset < HAMMER_BLOCKMAP_LAYER2;
                     block_offset += HAMMER_BIGBLOCK_SIZE) {
                        offset = phys_offset + block_offset;
                        /*
                         * Dive layer 2, each entry represents a big-block.
                         */
                        layer2_offset = layer1->phys_offset +
                                        HAMMER_BLOCKMAP_LAYER2_OFFSET(block_offset);
                        if (!hammer_test_offset("layer2", layer2_offset))
                                break;
                        layer2 = get_buffer_data(layer2_offset, &buffer2, 0);

                        if (layer2->zone == HAMMER_ZONE_BTREE_INDEX ||
                            layer2->zone == HAMMER_ZONE_META_INDEX) {
                                hammer_strip_bigblock(layer2->zone, offset);
                                layer2->zone = HAMMER_ZONE_UNAVAIL_INDEX;
                                layer2->append_off = HAMMER_BIGBLOCK_SIZE;
                                layer2->bytes_free = 0;
                                hammer_crc_set_layer2(HammerVersion, layer2);
                                buffer2->cache.modified = 1;
                        } else if (layer2->zone == HAMMER_ZONE_UNAVAIL_INDEX) {
                                break;
                        }
                }
        }
        rel_buffer(buffer1);
        rel_buffer(buffer2);

strip_header:
        for (i = 0; i < HAMMER_MAX_VOLUMES; i++) {
                volume = get_volume(i);
                if (volume) {
                        bzero(volume->ondisk, sizeof(*volume->ondisk));
                        memcpy(&volume->ondisk->vol_signature, "STRIPPED", 8);
                        printf("Stripped volume header %s\n", volume->name);
                }
        }

        flush_all_volumes();
}

static
int
hammer_test_offset(const char *msg, hammer_off_t offset)
{
        if (get_volume(HAMMER_VOL_DECODE(offset)) == NULL) {
                printf("Invalid volume# %d\n", HAMMER_VOL_DECODE(offset));
                return(0);
        }
        if (!hammer_is_zone_raw_buffer(offset)) {
                printf("Invalid %s offset 0x%jx\n", msg, offset);
                return(0);
        }

        return(1);
}

static
void
hammer_strip_bigblock(int zone, hammer_off_t offset)
{
        buffer_info_t buffer = NULL;
        int i;

        assert(hammer_is_index_record(zone));
        assert((offset & HAMMER_BIGBLOCK_MASK64) == 0);
        assert((offset & HAMMER_BUFMASK) == 0);
        offset = hammer_xlate_to_zoneX(zone, offset);

        /*
         * This format is taken from hammer blockmap.
         */
        printf("Stripped big-block ");
        if (VerboseOpt) {
                printf("%016jx zone=%-2d vol=%-3d L1#=%-6d L2#=%-6d L1=%-7lu L2=%-7lu\n",
                        offset,
                        zone,
                        HAMMER_VOL_DECODE(offset),
                        HAMMER_BLOCKMAP_LAYER1_INDEX(offset),
                        HAMMER_BLOCKMAP_LAYER2_INDEX(offset),
                        HAMMER_BLOCKMAP_LAYER1_OFFSET(offset),
                        HAMMER_BLOCKMAP_LAYER2_OFFSET(offset));
        } else {
                printf("%016jx\n", offset);
        }

        for (i = 0; i < HAMMER_BIGBLOCK_SIZE; i += HAMMER_BUFSIZE) {
                get_buffer_data(offset + i, &buffer, 1);
                assert(buffer);
        }
}

static
void
hammer_ask_yn(void)
{
        volume_info_t volume;
#define _HAMMER "HAMMER filesystem"
        char type[64];
        char label[64 + 4];
        int i;

        volume = get_root_volume();

        if (volume && volume->ondisk->vol_signature == HAMMER_FSBUF_VOLUME)
                strcpy(type, _HAMMER);
        else
                strcpy(type, "devices");

        if (volume && volume->ondisk->vol_label[0]) {
                snprintf(label, sizeof(label), " (%s)",
                        volume->ondisk->vol_label);
        } else {
                strcpy(label, "");
        }

        /*
         * This format is taken from hammer pfs-destroy.
         */
        printf("You have requested that %s%s be stripped", type, label);
        if (strcmp(type, _HAMMER))
                printf(", but %s may not be %s volumes\n", type, _HAMMER);
        else
                printf("\n");

        printf("Do you really want to do this? [y/n] ");
        fflush(stdout);
        if (getyn() == 0) {
                errx(1, "No action taken");
                /* not reached */
        }

        if (strcmp(type, _HAMMER)) {
                printf("Are you absolutely sure you want to do this? [y/n] ");
                fflush(stdout);
                if (getyn() == 0) {
                        errx(1, "No action taken");
                        /* not reached */
                }
        }

        printf("Stripping %s%s", type, label);

        if (DebugOpt) {
                printf("\n");
        } else {
                printf(" in");
                for (i = 5; i; --i) {
                        printf(" %d", i);
                        fflush(stdout);
                        sleep(1);
                }
                printf(".. starting destruction pass\n");
        }
}