--- /dev/null
+/*
+ * QEMU Block driver for CLOOP images
+ *
+ * Copyright (c) 2004 Johannes E. Schindelin
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+#include "qemu-common.h"
+#include "block/block_int.h"
+#include "qemu/module.h"
+#include <zlib.h>
+
+/* Maximum compressed block size */
+#define MAX_BLOCK_SIZE (64 * 1024 * 1024)
+
+typedef struct BDRVCloopState {
+ CoMutex lock;
+ uint32_t block_size;
+ uint32_t n_blocks;
+ uint64_t *offsets;
+ uint32_t sectors_per_block;
+ uint32_t current_block;
+ uint8_t *compressed_block;
+ uint8_t *uncompressed_block;
+ z_stream zstream;
+} BDRVCloopState;
+
+static int cloop_probe(const uint8_t *buf, int buf_size, const char *filename)
+{
+ const char *magic_version_2_0 = "#!/bin/sh\n"
+ "#V2.0 Format\n"
+ "modprobe cloop file=$0 && mount -r -t iso9660 /dev/cloop $1\n";
+ int length = strlen(magic_version_2_0);
+ if (length > buf_size) {
+ length = buf_size;
+ }
+ if (!memcmp(magic_version_2_0, buf, length)) {
+ return 2;
+ }
+ return 0;
+}
+
+static int cloop_open(BlockDriverState *bs, QDict *options, int flags,
+ Error **errp)
+{
+ BDRVCloopState *s = bs->opaque;
+ uint32_t offsets_size, max_compressed_block_size = 1, i;
+ int ret;
+
+ bs->read_only = 1;
+
+ /* read header */
+ ret = bdrv_pread(bs->file, 128, &s->block_size, 4);
+ if (ret < 0) {
+ return ret;
+ }
+ s->block_size = be32_to_cpu(s->block_size);
+ if (s->block_size % 512) {
+ error_setg(errp, "block_size %" PRIu32 " must be a multiple of 512",
+ s->block_size);
+ return -EINVAL;
+ }
+ if (s->block_size == 0) {
+ error_setg(errp, "block_size cannot be zero");
+ return -EINVAL;
+ }
+
+ /* cloop's create_compressed_fs.c warns about block sizes beyond 256 KB but
+ * we can accept more. Prevent ridiculous values like 4 GB - 1 since we
+ * need a buffer this big.
+ */
+ if (s->block_size > MAX_BLOCK_SIZE) {
+ error_setg(errp, "block_size %" PRIu32 " must be %u MB or less",
+ s->block_size,
+ MAX_BLOCK_SIZE / (1024 * 1024));
+ return -EINVAL;
+ }
+
+ ret = bdrv_pread(bs->file, 128 + 4, &s->n_blocks, 4);
+ if (ret < 0) {
+ return ret;
+ }
+ s->n_blocks = be32_to_cpu(s->n_blocks);
+
+ /* read offsets */
+ if (s->n_blocks > (UINT32_MAX - 1) / sizeof(uint64_t)) {
+ /* Prevent integer overflow */
+ error_setg(errp, "n_blocks %" PRIu32 " must be %zu or less",
+ s->n_blocks,
+ (UINT32_MAX - 1) / sizeof(uint64_t));
+ return -EINVAL;
+ }
+ offsets_size = (s->n_blocks + 1) * sizeof(uint64_t);
+ if (offsets_size > 512 * 1024 * 1024) {
+ /* Prevent ridiculous offsets_size which causes memory allocation to
+ * fail or overflows bdrv_pread() size. In practice the 512 MB
+ * offsets[] limit supports 16 TB images at 256 KB block size.
+ */
+ error_setg(errp, "image requires too many offsets, "
+ "try increasing block size");
+ return -EINVAL;
+ }
+
+ s->offsets = g_try_malloc(offsets_size);
+ if (s->offsets == NULL) {
+ error_setg(errp, "Could not allocate offsets table");
+ return -ENOMEM;
+ }
+
+ ret = bdrv_pread(bs->file, 128 + 4 + 4, s->offsets, offsets_size);
+ if (ret < 0) {
+ goto fail;
+ }
+
+ for (i = 0; i < s->n_blocks + 1; i++) {
+ uint64_t size;
+
+ s->offsets[i] = be64_to_cpu(s->offsets[i]);
+ if (i == 0) {
+ continue;
+ }
+
+ if (s->offsets[i] < s->offsets[i - 1]) {
+ error_setg(errp, "offsets not monotonically increasing at "
+ "index %" PRIu32 ", image file is corrupt", i);
+ ret = -EINVAL;
+ goto fail;
+ }
+
+ size = s->offsets[i] - s->offsets[i - 1];
+
+ /* Compressed blocks should be smaller than the uncompressed block size
+ * but maybe compression performed poorly so the compressed block is
+ * actually bigger. Clamp down on unrealistic values to prevent
+ * ridiculous s->compressed_block allocation.
+ */
+ if (size > 2 * MAX_BLOCK_SIZE) {
+ error_setg(errp, "invalid compressed block size at index %" PRIu32
+ ", image file is corrupt", i);
+ ret = -EINVAL;
+ goto fail;
+ }
+
+ if (size > max_compressed_block_size) {
+ max_compressed_block_size = size;
+ }
+ }
+
+ /* initialize zlib engine */
+ s->compressed_block = g_try_malloc(max_compressed_block_size + 1);
+ if (s->compressed_block == NULL) {
+ error_setg(errp, "Could not allocate compressed_block");
+ ret = -ENOMEM;
+ goto fail;
+ }
+
+ s->uncompressed_block = g_try_malloc(s->block_size);
+ if (s->uncompressed_block == NULL) {
+ error_setg(errp, "Could not allocate uncompressed_block");
+ ret = -ENOMEM;
+ goto fail;
+ }
+
+ if (inflateInit(&s->zstream) != Z_OK) {
+ ret = -EINVAL;
+ goto fail;
+ }
+ s->current_block = s->n_blocks;
+
+ s->sectors_per_block = s->block_size/512;
+ bs->total_sectors = s->n_blocks * s->sectors_per_block;
+ qemu_co_mutex_init(&s->lock);
+ return 0;
+
+fail:
+ g_free(s->offsets);
+ g_free(s->compressed_block);
+ g_free(s->uncompressed_block);
+ return ret;
+}
+
+static inline int cloop_read_block(BlockDriverState *bs, int block_num)
+{
+ BDRVCloopState *s = bs->opaque;
+
+ if (s->current_block != block_num) {
+ int ret;
+ uint32_t bytes = s->offsets[block_num + 1] - s->offsets[block_num];
+
+ ret = bdrv_pread(bs->file, s->offsets[block_num], s->compressed_block,
+ bytes);
+ if (ret != bytes) {
+ return -1;
+ }
+
+ s->zstream.next_in = s->compressed_block;
+ s->zstream.avail_in = bytes;
+ s->zstream.next_out = s->uncompressed_block;
+ s->zstream.avail_out = s->block_size;
+ ret = inflateReset(&s->zstream);
+ if (ret != Z_OK) {
+ return -1;
+ }
+ ret = inflate(&s->zstream, Z_FINISH);
+ if (ret != Z_STREAM_END || s->zstream.total_out != s->block_size) {
+ return -1;
+ }
+
+ s->current_block = block_num;
+ }
+ return 0;
+}
+
+static int cloop_read(BlockDriverState *bs, int64_t sector_num,
+ uint8_t *buf, int nb_sectors)
+{
+ BDRVCloopState *s = bs->opaque;
+ int i;
+
+ for (i = 0; i < nb_sectors; i++) {
+ uint32_t sector_offset_in_block =
+ ((sector_num + i) % s->sectors_per_block),
+ block_num = (sector_num + i) / s->sectors_per_block;
+ if (cloop_read_block(bs, block_num) != 0) {
+ return -1;
+ }
+ memcpy(buf + i * 512,
+ s->uncompressed_block + sector_offset_in_block * 512, 512);
+ }
+ return 0;
+}
+
+static coroutine_fn int cloop_co_read(BlockDriverState *bs, int64_t sector_num,
+ uint8_t *buf, int nb_sectors)
+{
+ int ret;
+ BDRVCloopState *s = bs->opaque;
+ qemu_co_mutex_lock(&s->lock);
+ ret = cloop_read(bs, sector_num, buf, nb_sectors);
+ qemu_co_mutex_unlock(&s->lock);
+ return ret;
+}
+
+static void cloop_close(BlockDriverState *bs)
+{
+ BDRVCloopState *s = bs->opaque;
+ g_free(s->offsets);
+ g_free(s->compressed_block);
+ g_free(s->uncompressed_block);
+ inflateEnd(&s->zstream);
+}
+
+static BlockDriver bdrv_cloop = {
+ .format_name = "cloop",
+ .instance_size = sizeof(BDRVCloopState),
+ .bdrv_probe = cloop_probe,
+ .bdrv_open = cloop_open,
+ .bdrv_read = cloop_co_read,
+ .bdrv_close = cloop_close,
+};
+
+static void bdrv_cloop_init(void)
+{
+ bdrv_register(&bdrv_cloop);
+}
+
+block_init(bdrv_cloop_init);
Code Review / kvmfornfv.git / blobdiff