Some code in the block layer makes potentially huge allocations. Failure is not completely unexpected there, so avoid aborting qemu and handle out-of-memory situations gracefully. This patch addresses the allocations in the parallels block driver. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Benoit Canet <benoit@irqsave.net>
194 lines
5.3 KiB
C
194 lines
5.3 KiB
C
/*
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* Block driver for Parallels disk image format
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*
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* Copyright (c) 2007 Alex Beregszaszi
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*
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* This code is based on comparing different disk images created by Parallels.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include "qemu-common.h"
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#include "block/block_int.h"
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#include "qemu/module.h"
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/**************************************************************/
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#define HEADER_MAGIC "WithoutFreeSpace"
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#define HEADER_VERSION 2
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#define HEADER_SIZE 64
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// always little-endian
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struct parallels_header {
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char magic[16]; // "WithoutFreeSpace"
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uint32_t version;
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uint32_t heads;
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uint32_t cylinders;
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uint32_t tracks;
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uint32_t catalog_entries;
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uint32_t nb_sectors;
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char padding[24];
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} QEMU_PACKED;
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typedef struct BDRVParallelsState {
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CoMutex lock;
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uint32_t *catalog_bitmap;
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unsigned int catalog_size;
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unsigned int tracks;
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} BDRVParallelsState;
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static int parallels_probe(const uint8_t *buf, int buf_size, const char *filename)
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{
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const struct parallels_header *ph = (const void *)buf;
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if (buf_size < HEADER_SIZE)
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return 0;
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if (!memcmp(ph->magic, HEADER_MAGIC, 16) &&
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(le32_to_cpu(ph->version) == HEADER_VERSION))
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return 100;
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return 0;
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}
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static int parallels_open(BlockDriverState *bs, QDict *options, int flags,
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Error **errp)
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{
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BDRVParallelsState *s = bs->opaque;
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int i;
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struct parallels_header ph;
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int ret;
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bs->read_only = 1; // no write support yet
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ret = bdrv_pread(bs->file, 0, &ph, sizeof(ph));
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if (ret < 0) {
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goto fail;
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}
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if (memcmp(ph.magic, HEADER_MAGIC, 16) ||
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(le32_to_cpu(ph.version) != HEADER_VERSION)) {
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error_setg(errp, "Image not in Parallels format");
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ret = -EINVAL;
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goto fail;
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}
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bs->total_sectors = le32_to_cpu(ph.nb_sectors);
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s->tracks = le32_to_cpu(ph.tracks);
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if (s->tracks == 0) {
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error_setg(errp, "Invalid image: Zero sectors per track");
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ret = -EINVAL;
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goto fail;
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}
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s->catalog_size = le32_to_cpu(ph.catalog_entries);
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if (s->catalog_size > INT_MAX / 4) {
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error_setg(errp, "Catalog too large");
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ret = -EFBIG;
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goto fail;
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}
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s->catalog_bitmap = g_try_malloc(s->catalog_size * 4);
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if (s->catalog_size && s->catalog_bitmap == NULL) {
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ret = -ENOMEM;
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goto fail;
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}
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ret = bdrv_pread(bs->file, 64, s->catalog_bitmap, s->catalog_size * 4);
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if (ret < 0) {
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goto fail;
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}
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for (i = 0; i < s->catalog_size; i++)
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le32_to_cpus(&s->catalog_bitmap[i]);
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qemu_co_mutex_init(&s->lock);
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return 0;
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fail:
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g_free(s->catalog_bitmap);
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return ret;
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}
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static int64_t seek_to_sector(BlockDriverState *bs, int64_t sector_num)
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{
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BDRVParallelsState *s = bs->opaque;
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uint32_t index, offset;
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index = sector_num / s->tracks;
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offset = sector_num % s->tracks;
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/* not allocated */
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if ((index > s->catalog_size) || (s->catalog_bitmap[index] == 0))
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return -1;
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return (uint64_t)(s->catalog_bitmap[index] + offset) * 512;
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}
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static int parallels_read(BlockDriverState *bs, int64_t sector_num,
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uint8_t *buf, int nb_sectors)
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{
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while (nb_sectors > 0) {
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int64_t position = seek_to_sector(bs, sector_num);
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if (position >= 0) {
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if (bdrv_pread(bs->file, position, buf, 512) != 512)
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return -1;
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} else {
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memset(buf, 0, 512);
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}
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nb_sectors--;
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sector_num++;
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buf += 512;
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}
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return 0;
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}
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static coroutine_fn int parallels_co_read(BlockDriverState *bs, int64_t sector_num,
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uint8_t *buf, int nb_sectors)
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{
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int ret;
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BDRVParallelsState *s = bs->opaque;
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qemu_co_mutex_lock(&s->lock);
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ret = parallels_read(bs, sector_num, buf, nb_sectors);
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qemu_co_mutex_unlock(&s->lock);
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return ret;
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}
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static void parallels_close(BlockDriverState *bs)
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{
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BDRVParallelsState *s = bs->opaque;
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g_free(s->catalog_bitmap);
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}
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static BlockDriver bdrv_parallels = {
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.format_name = "parallels",
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.instance_size = sizeof(BDRVParallelsState),
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.bdrv_probe = parallels_probe,
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.bdrv_open = parallels_open,
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.bdrv_read = parallels_co_read,
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.bdrv_close = parallels_close,
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};
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static void bdrv_parallels_init(void)
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{
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bdrv_register(&bdrv_parallels);
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}
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block_init(bdrv_parallels_init);
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