From 275734e4794bb7a3d73f7517fbd769727f2479af Mon Sep 17 00:00:00 2001 From: Markus Armbruster Date: Thu, 17 Dec 2020 17:20:01 +0100 Subject: [PATCH] block/vpc: Pad VHDFooter, replace uint8_t[] buffers Pad VHDFooter as specified in the "Virtual Hard Disk Image Format Specification" version 1.0[*]. Change footer buffers from uint8_t[HEADER_SIZE] to VHDFooter. Their size remains the same. The VHDFooter * variables pointing to a VHDFooter variable right next to it are now silly. Eliminate them, and shorten the remaining variables' names. Most variables pointing to s->footer are now also silly. Eliminate them, too. [*] http://download.microsoft.com/download/f/f/e/ffef50a5-07dd-4cf8-aaa3-442c0673a029/Virtual%20Hard%20Disk%20Format%20Spec_10_18_06.doc Signed-off-by: Markus Armbruster Message-Id: <20201217162003.1102738-8-armbru@redhat.com> Reviewed-by: Max Reitz Signed-off-by: Kevin Wolf --- block/vpc.c | 77 +++++++++++++++++++++++++---------------------------- 1 file changed, 37 insertions(+), 40 deletions(-) diff --git a/block/vpc.c b/block/vpc.c index 6cb656ac82..f3ea92dcb0 100644 --- a/block/vpc.c +++ b/block/vpc.c @@ -95,8 +95,11 @@ typedef struct vhd_footer { QemuUUID uuid; uint8_t in_saved_state; + uint8_t reserved[427]; } QEMU_PACKED VHDFooter; +QEMU_BUILD_BUG_ON(sizeof(VHDFooter) != 512); + typedef struct vhd_dyndisk_header { char magic[8]; /* "cxsparse" */ @@ -134,7 +137,7 @@ QEMU_BUILD_BUG_ON(sizeof(VHDDynDiskHeader) != 1024); typedef struct BDRVVPCState { CoMutex lock; - uint8_t footer_buf[HEADER_SIZE]; + VHDFooter footer; uint64_t free_data_block_offset; int max_table_entries; uint32_t *pagetable; @@ -250,13 +253,13 @@ static int vpc_open(BlockDriverState *bs, QDict *options, int flags, goto fail; } - ret = bdrv_pread(bs->file, 0, s->footer_buf, HEADER_SIZE); + ret = bdrv_pread(bs->file, 0, &s->footer, HEADER_SIZE); if (ret < 0) { error_setg(errp, "Unable to read VHD header"); goto fail; } - footer = (VHDFooter *) s->footer_buf; + footer = &s->footer; if (strncmp(footer->creator, "conectix", 8)) { int64_t offset = bdrv_getlength(bs->file->bs); if (offset < 0) { @@ -270,7 +273,7 @@ static int vpc_open(BlockDriverState *bs, QDict *options, int flags, } /* If a fixed disk, the footer is found only at the end of the file */ - ret = bdrv_pread(bs->file, offset-HEADER_SIZE, s->footer_buf, + ret = bdrv_pread(bs->file, offset - HEADER_SIZE, footer, HEADER_SIZE); if (ret < 0) { goto fail; @@ -285,7 +288,7 @@ static int vpc_open(BlockDriverState *bs, QDict *options, int flags, checksum = be32_to_cpu(footer->checksum); footer->checksum = 0; - if (vpc_checksum(s->footer_buf, HEADER_SIZE) != checksum) { + if (vpc_checksum(footer, HEADER_SIZE) != checksum) { error_setg(errp, "Incorrect header checksum"); ret = -EINVAL; goto fail; @@ -535,7 +538,7 @@ static int rewrite_footer(BlockDriverState *bs) BDRVVPCState *s = bs->opaque; int64_t offset = s->free_data_block_offset; - ret = bdrv_pwrite_sync(bs->file, offset, s->footer_buf, HEADER_SIZE); + ret = bdrv_pwrite_sync(bs->file, offset, &s->footer, HEADER_SIZE); if (ret < 0) return ret; @@ -598,9 +601,8 @@ fail: static int vpc_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) { BDRVVPCState *s = (BDRVVPCState *)bs->opaque; - VHDFooter *footer = (VHDFooter *) s->footer_buf; - if (be32_to_cpu(footer->type) != VHD_FIXED) { + if (be32_to_cpu(s->footer.type) != VHD_FIXED) { bdi->cluster_size = s->block_size; } @@ -616,10 +618,9 @@ vpc_co_preadv(BlockDriverState *bs, uint64_t offset, uint64_t bytes, int64_t image_offset; int64_t n_bytes; int64_t bytes_done = 0; - VHDFooter *footer = (VHDFooter *) s->footer_buf; QEMUIOVector local_qiov; - if (be32_to_cpu(footer->type) == VHD_FIXED) { + if (be32_to_cpu(s->footer.type) == VHD_FIXED) { return bdrv_co_preadv(bs->file, offset, bytes, qiov, 0); } @@ -667,10 +668,9 @@ vpc_co_pwritev(BlockDriverState *bs, uint64_t offset, uint64_t bytes, int64_t n_bytes; int64_t bytes_done = 0; int ret = 0; - VHDFooter *footer = (VHDFooter *) s->footer_buf; QEMUIOVector local_qiov; - if (be32_to_cpu(footer->type) == VHD_FIXED) { + if (be32_to_cpu(s->footer.type) == VHD_FIXED) { return bdrv_co_pwritev(bs->file, offset, bytes, qiov, 0); } @@ -724,13 +724,12 @@ static int coroutine_fn vpc_co_block_status(BlockDriverState *bs, BlockDriverState **file) { BDRVVPCState *s = bs->opaque; - VHDFooter *footer = (VHDFooter*) s->footer_buf; int64_t image_offset; bool allocated; int ret; int64_t n; - if (be32_to_cpu(footer->type) == VHD_FIXED) { + if (be32_to_cpu(s->footer.type) == VHD_FIXED) { *pnum = bytes; *map = offset; *file = bs->file->bs; @@ -973,8 +972,7 @@ static int coroutine_fn vpc_co_create(BlockdevCreateOptions *opts, BlockBackend *blk = NULL; BlockDriverState *bs = NULL; - uint8_t footer_buf[HEADER_SIZE]; - VHDFooter *footer = (VHDFooter *)footer_buf; + VHDFooter footer; uint16_t cyls = 0; uint8_t heads = 0; uint8_t secs_per_cyl = 0; @@ -1037,48 +1035,48 @@ static int coroutine_fn vpc_co_create(BlockdevCreateOptions *opts, } /* Prepare the Hard Disk Footer */ - memset(footer_buf, 0, HEADER_SIZE); + memset(&footer, 0, HEADER_SIZE); - memcpy(footer->creator, "conectix", 8); + memcpy(footer.creator, "conectix", 8); if (vpc_opts->force_size) { - memcpy(footer->creator_app, "qem2", 4); + memcpy(footer.creator_app, "qem2", 4); } else { - memcpy(footer->creator_app, "qemu", 4); + memcpy(footer.creator_app, "qemu", 4); } - memcpy(footer->creator_os, "Wi2k", 4); + memcpy(footer.creator_os, "Wi2k", 4); - footer->features = cpu_to_be32(0x02); - footer->version = cpu_to_be32(0x00010000); + footer.features = cpu_to_be32(0x02); + footer.version = cpu_to_be32(0x00010000); if (disk_type == VHD_DYNAMIC) { - footer->data_offset = cpu_to_be64(HEADER_SIZE); + footer.data_offset = cpu_to_be64(HEADER_SIZE); } else { - footer->data_offset = cpu_to_be64(0xFFFFFFFFFFFFFFFFULL); + footer.data_offset = cpu_to_be64(0xFFFFFFFFFFFFFFFFULL); } - footer->timestamp = cpu_to_be32(time(NULL) - VHD_TIMESTAMP_BASE); + footer.timestamp = cpu_to_be32(time(NULL) - VHD_TIMESTAMP_BASE); /* Version of Virtual PC 2007 */ - footer->major = cpu_to_be16(0x0005); - footer->minor = cpu_to_be16(0x0003); - footer->orig_size = cpu_to_be64(total_size); - footer->current_size = cpu_to_be64(total_size); - footer->cyls = cpu_to_be16(cyls); - footer->heads = heads; - footer->secs_per_cyl = secs_per_cyl; + footer.major = cpu_to_be16(0x0005); + footer.minor = cpu_to_be16(0x0003); + footer.orig_size = cpu_to_be64(total_size); + footer.current_size = cpu_to_be64(total_size); + footer.cyls = cpu_to_be16(cyls); + footer.heads = heads; + footer.secs_per_cyl = secs_per_cyl; - footer->type = cpu_to_be32(disk_type); + footer.type = cpu_to_be32(disk_type); qemu_uuid_generate(&uuid); - footer->uuid = uuid; + footer.uuid = uuid; - footer->checksum = cpu_to_be32(vpc_checksum(footer_buf, HEADER_SIZE)); + footer.checksum = cpu_to_be32(vpc_checksum(&footer, HEADER_SIZE)); if (disk_type == VHD_DYNAMIC) { - ret = create_dynamic_disk(blk, footer_buf, total_sectors); + ret = create_dynamic_disk(blk, (uint8_t *)&footer, total_sectors); if (ret < 0) { error_setg(errp, "Unable to create or write VHD header"); } } else { - ret = create_fixed_disk(blk, footer_buf, total_size, errp); + ret = create_fixed_disk(blk, (uint8_t *)&footer, total_size, errp); } out: @@ -1172,9 +1170,8 @@ fail: static int vpc_has_zero_init(BlockDriverState *bs) { BDRVVPCState *s = bs->opaque; - VHDFooter *footer = (VHDFooter *) s->footer_buf; - if (be32_to_cpu(footer->type) == VHD_FIXED) { + if (be32_to_cpu(s->footer.type) == VHD_FIXED) { return bdrv_has_zero_init(bs->file->bs); } else { return 1;