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-rw-r--r--lib/sqfs/block_writer.c235
1 files changed, 235 insertions, 0 deletions
diff --git a/lib/sqfs/block_writer.c b/lib/sqfs/block_writer.c
new file mode 100644
index 0000000..c955532
--- /dev/null
+++ b/lib/sqfs/block_writer.c
@@ -0,0 +1,235 @@
+/* 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.h"
+
+#include <stdlib.h>
+
+#define MK_BLK_HASH(chksum, size) \
+ (((sqfs_u64)(size) << 32) | (sqfs_u64)(chksum))
+
+#define INIT_BLOCK_COUNT (128)
+
+typedef struct {
+ sqfs_u64 offset;
+ sqfs_u64 hash;
+} blk_info_t;
+
+struct sqfs_block_writer_t {
+ sqfs_file_t *file;
+
+ size_t num_blocks;
+ size_t max_blocks;
+ blk_info_t *blocks;
+ size_t devblksz;
+
+ const sqfs_block_hooks_t *hooks;
+ void *user_ptr;
+
+ sqfs_u64 start;
+ size_t file_start;
+};
+
+static int store_block_location(sqfs_block_writer_t *wr, sqfs_u64 offset,
+ sqfs_u32 size, sqfs_u32 chksum)
+{
+ size_t new_sz;
+ void *new;
+
+ if (wr->num_blocks == wr->max_blocks) {
+ new_sz = wr->max_blocks * 2;
+ new = realloc(wr->blocks, sizeof(wr->blocks[0]) * new_sz);
+
+ if (new == NULL)
+ return SQFS_ERROR_ALLOC;
+
+ wr->blocks = new;
+ wr->max_blocks = new_sz;
+ }
+
+ wr->blocks[wr->num_blocks].offset = offset;
+ wr->blocks[wr->num_blocks].hash = MK_BLK_HASH(chksum, size);
+ wr->num_blocks += 1;
+ return 0;
+}
+
+static size_t deduplicate_blocks(sqfs_block_writer_t *wr, size_t count)
+{
+ size_t i, j;
+
+ for (i = 0; i < wr->file_start; ++i) {
+ for (j = 0; j < count; ++j) {
+ if (wr->blocks[i + j].hash == 0)
+ break;
+
+ if (wr->blocks[i + j].hash !=
+ wr->blocks[wr->file_start + j].hash)
+ break;
+ }
+
+ if (j == count)
+ break;
+ }
+
+ return i;
+}
+
+static int align_file(sqfs_block_writer_t *wr, sqfs_block_t *blk)
+{
+ void *padding;
+ sqfs_u64 size;
+ size_t diff;
+ int ret;
+
+ if (!(blk->flags & SQFS_BLK_ALIGN))
+ return 0;
+
+ size = wr->file->get_size(wr->file);
+ diff = size % wr->devblksz;
+ if (diff == 0)
+ return 0;
+
+ padding = calloc(1, diff);
+ if (padding == 0)
+ return SQFS_ERROR_ALLOC;
+
+ if (wr->hooks != NULL && wr->hooks->prepare_padding != NULL)
+ wr->hooks->prepare_padding(wr->user_ptr, padding, diff);
+
+ ret = wr->file->write_at(wr->file, size, padding, diff);
+ free(padding);
+ if (ret)
+ return ret;
+
+ return store_block_location(wr, size, 0, 0);
+}
+
+sqfs_block_writer_t *sqfs_block_writer_create(sqfs_file_t *file,
+ size_t devblksz, sqfs_u32 flags)
+{
+ sqfs_block_writer_t *wr;
+
+ if (flags != 0)
+ return NULL;
+
+ wr = calloc(1, sizeof(*wr));
+ if (wr == NULL)
+ return NULL;
+
+ wr->file = file;
+ wr->devblksz = devblksz;
+ wr->max_blocks = INIT_BLOCK_COUNT;
+
+ wr->blocks = alloc_array(sizeof(wr->blocks[0]), wr->max_blocks);
+ if (wr->blocks == NULL) {
+ free(wr);
+ return NULL;
+ }
+
+ return wr;
+}
+
+int sqfs_block_writer_set_hooks(sqfs_block_writer_t *wr, void *user_ptr,
+ const sqfs_block_hooks_t *hooks)
+{
+ if (hooks->size != sizeof(*hooks))
+ return SQFS_ERROR_UNSUPPORTED;
+
+ wr->hooks = hooks;
+ wr->user_ptr = user_ptr;
+ return 0;
+}
+
+void sqfs_block_writer_destroy(sqfs_block_writer_t *wr)
+{
+ free(wr->blocks);
+ free(wr);
+}
+
+int sqfs_block_writer_write(sqfs_block_writer_t *wr, sqfs_block_t *block,
+ sqfs_u64 *location)
+{
+ sqfs_u64 offset, bytes;
+ size_t start, count;
+ sqfs_u32 out;
+ int err;
+
+ if (wr->hooks != NULL && wr->hooks->pre_block_write != NULL)
+ wr->hooks->pre_block_write(wr->user_ptr, block, wr->file);
+
+ if (block->flags & SQFS_BLK_FIRST_BLOCK) {
+ wr->start = wr->file->get_size(wr->file);
+ wr->file_start = wr->num_blocks;
+
+ err = align_file(wr, block);
+ if (err)
+ return err;
+ }
+
+ if (block->size != 0) {
+ out = block->size;
+ if (!(block->flags & SQFS_BLK_IS_COMPRESSED))
+ out |= 1 << 24;
+
+ offset = wr->file->get_size(wr->file);
+ *location = offset;
+
+ err = store_block_location(wr, offset, out, block->checksum);
+ if (err)
+ return err;
+
+ err = wr->file->write_at(wr->file, offset,
+ block->data, block->size);
+ if (err)
+ return err;
+ }
+
+ if (wr->hooks != NULL && wr->hooks->post_block_write != NULL)
+ wr->hooks->post_block_write(wr->user_ptr, block, wr->file);
+
+ if (block->flags & SQFS_BLK_LAST_BLOCK) {
+ err = align_file(wr, block);
+ if (err)
+ return err;
+
+ count = wr->num_blocks - wr->file_start;
+ start = deduplicate_blocks(wr, count);
+ offset = wr->blocks[start].offset;
+
+ *location = offset;
+ if (start >= wr->file_start)
+ return 0;
+
+ offset = start + count;
+ if (offset >= wr->file_start) {
+ count = wr->num_blocks - offset;
+ wr->num_blocks = offset;
+ } else {
+ wr->num_blocks = wr->file_start;
+ }
+
+ if (wr->hooks != NULL &&
+ wr->hooks->notify_blocks_erased != NULL) {
+ bytes = wr->file->get_size(wr->file) - wr->start;
+
+ wr->hooks->notify_blocks_erased(wr->user_ptr,
+ count, bytes);
+ }
+
+ err = wr->file->truncate(wr->file, wr->start);
+ if (err)
+ return err;
+ }
+
+ return 0;
+}