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/* SPDX-License-Identifier: LGPL-3.0-or-later */
/*
* block_writer.c
*
* Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
*/
#define SQFS_BUILDING_DLL
#include "config.h"
#include "sqfs/block_writer.h"
#include "sqfs/error.h"
#include "sqfs/block.h"
#include "sqfs/io.h"
#include "util/array.h"
#include "util/util.h"
#include <stdlib.h>
#include <string.h>
#define MK_BLK_HASH(chksum, size) \
(((sqfs_u64)(size) << 32) | (sqfs_u64)(chksum))
#define SIZE_FROM_HASH(hash) ((hash >> 32) & ((1 << 24) - 1))
#define INIT_BLOCK_COUNT (128)
#define SCRATCH_SIZE (8192)
typedef struct {
sqfs_u64 offset;
sqfs_u64 hash;
} blk_info_t;
typedef struct {
sqfs_block_writer_t base;
sqfs_file_t *file;
array_t blocks;
size_t file_start;
sqfs_u32 flags;
sqfs_u8 scratch[];
} block_writer_default_t;
static int store_block_location(block_writer_default_t *wr, sqfs_u64 offset,
sqfs_u32 size, sqfs_u32 chksum)
{
blk_info_t info = { offset, MK_BLK_HASH(chksum, size) };
return array_append(&(wr->blocks), &info);
}
static int deduplicate_blocks(block_writer_default_t *wr, sqfs_u32 flags, sqfs_u64 *out)
{
const blk_info_t *blocks = wr->blocks.data;
sqfs_u64 loc_a, loc_b, sz;
size_t i, j, count;
int ret;
count = wr->blocks.used - wr->file_start;
if (count == 0) {
*out = 0;
return 0;
}
if (flags & SQFS_BLK_DONT_DEDUPLICATE) {
*out = blocks[wr->file_start].offset;
return 0;
}
sz = 0;
loc_a = blocks[wr->file_start].offset;
for (i = 0; i < count; ++i)
sz += SIZE_FROM_HASH(blocks[wr->file_start + i].hash);
for (i = 0; i < wr->file_start; ++i) {
for (j = 0; j < count; ++j) {
if (blocks[i + j].hash !=
blocks[wr->file_start + j].hash)
break;
}
if (j != count)
continue;
if (wr->flags & SQFS_BLOCK_WRITER_HASH_COMPARE_ONLY)
break;
loc_b = blocks[i].offset;
ret = check_file_range_equal(wr->file, wr->scratch,
SCRATCH_SIZE, loc_a, loc_b, sz);
if (ret == 0)
break;
if (ret < 0)
return ret;
}
*out = blocks[i].offset;
if (i >= wr->file_start)
return 0;
if (count >= (wr->file_start - i)) {
wr->blocks.used = i + count;
} else {
wr->blocks.used = wr->file_start;
}
sz = blocks[wr->blocks.used - 1].offset +
SIZE_FROM_HASH(blocks[wr->blocks.used - 1].hash);
return wr->file->truncate(wr->file, sz);
}
static void block_writer_destroy(sqfs_object_t *wr)
{
sqfs_drop(((block_writer_default_t *)wr)->file);
array_cleanup(&(((block_writer_default_t *)wr)->blocks));
free(wr);
}
static int write_data_block(sqfs_block_writer_t *base, void *user,
sqfs_u32 size, sqfs_u32 checksum, sqfs_u32 flags,
const sqfs_u8 *data, sqfs_u64 *location)
{
block_writer_default_t *wr = (block_writer_default_t *)base;
int err;
(void)user;
if (flags & SQFS_BLK_FIRST_BLOCK)
wr->file_start = wr->blocks.used;
*location = wr->file->get_size(wr->file);
if (size != 0 && !(flags & SQFS_BLK_IS_SPARSE)) {
sqfs_u32 out = size;
if (!(flags & SQFS_BLK_IS_COMPRESSED))
out |= 1 << 24;
err = store_block_location(wr, *location, out, checksum);
if (err)
return err;
err = wr->file->write_at(wr->file, *location, data, size);
if (err)
return err;
}
if (flags & SQFS_BLK_LAST_BLOCK)
return deduplicate_blocks(wr, flags, location);
return 0;
}
static sqfs_u64 get_block_count(const sqfs_block_writer_t *wr)
{
return ((const block_writer_default_t *)wr)->blocks.used;
}
sqfs_block_writer_t *sqfs_block_writer_create(sqfs_file_t *file, sqfs_u32 flags)
{
block_writer_default_t *wr;
if (flags & ~SQFS_BLOCK_WRITER_ALL_FLAGS)
return NULL;
if (flags & SQFS_BLOCK_WRITER_HASH_COMPARE_ONLY) {
wr = calloc(1, sizeof(*wr));
} else {
wr = alloc_flex(sizeof(*wr), 1, SCRATCH_SIZE);
}
if (wr == NULL)
return NULL;
sqfs_object_init(wr, block_writer_destroy, NULL);
((sqfs_block_writer_t *)wr)->write_data_block = write_data_block;
((sqfs_block_writer_t *)wr)->get_block_count = get_block_count;
wr->flags = flags;
wr->file = sqfs_grab(file);
if (array_init(&(wr->blocks), sizeof(blk_info_t), INIT_BLOCK_COUNT)) {
sqfs_drop(wr->file);
free(wr);
return NULL;
}
return (sqfs_block_writer_t *)wr;
}
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