/* * 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);