From 6e9ea0c0629fe25723494a19498bedf4b781cbfa Mon Sep 17 00:00:00 2001 From: aurel32 Date: Wed, 15 Apr 2009 14:42:46 +0000 Subject: block-vpc: Don't silently create smaller image than requested The algorithm from the VHD specification for CHS calculation silently limits images to 127 GB which may confuse a user who requested a larger image. Better output an error message and abort. Signed-off-by: Kevin Wolf Signed-off-by: Aurelien Jarno git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@7109 c046a42c-6fe2-441c-8c8c-71466251a162 --- block-vpc.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) (limited to 'block-vpc.c') diff --git a/block-vpc.c b/block-vpc.c index 7ae520235..71a171d0e 100644 --- a/block-vpc.c +++ b/block-vpc.c @@ -433,14 +433,16 @@ static int vpc_write(BlockDriverState *bs, int64_t sector_num, * * Note that the geometry doesn't always exactly match total_sectors but * may round it down. + * + * Returns 0 on success, -EFBIG if the size is larger than 127 GB */ -static void calculate_geometry(int64_t total_sectors, uint16_t* cyls, +static int calculate_geometry(int64_t total_sectors, uint16_t* cyls, uint8_t* heads, uint8_t* secs_per_cyl) { uint32_t cyls_times_heads; if (total_sectors > 65535 * 16 * 255) - total_sectors = 65535 * 16 * 255; + return -EFBIG; if (total_sectors > 65535 * 16 * 63) { *secs_per_cyl = 255; @@ -470,6 +472,8 @@ static void calculate_geometry(int64_t total_sectors, uint16_t* cyls, // Note: Rounding up deviates from the Virtual PC behaviour // However, we need this to avoid truncating images in qemu-img convert *cyls = (cyls_times_heads + *heads - 1) / *heads; + + return 0; } static int vpc_create(const char *filename, int64_t total_sectors, @@ -493,7 +497,8 @@ static int vpc_create(const char *filename, int64_t total_sectors, return -EIO; // Calculate matching total_size and geometry - calculate_geometry(total_sectors, &cyls, &heads, &secs_per_cyl); + if (calculate_geometry(total_sectors, &cyls, &heads, &secs_per_cyl)) + return -EFBIG; total_sectors = (int64_t) cyls * heads * secs_per_cyl; // Prepare the Hard Disk Footer -- cgit v1.2.3