diff options
| author | Nam T. Nguyen <namnguyen@chromium.org> | 2014-12-15 11:03:36 -0800 |
|---|---|---|
| committer | chrome-internal-fetch <chrome-internal-fetch@google.com> | 2014-12-16 01:28:48 +0000 |
| commit | d53b6684a2b451e41d9af84829b08a0c3325792f (patch) | |
| tree | 051b4914cfb15b3a26a34e420dd42a205cc83ec5 | |
| parent | 3f4d8d05ba4e32990c8584bd47cdf082d4604232 (diff) | |
| download | vboot-d53b6684a2b451e41d9af84829b08a0c3325792f.tar.gz | |
cgpt: Rework number of entries calculation
As pointed out by Daniel in CL:234996, the half_size_sectors should have
been checked in both places.
This CL reworks that part of the code to read easier.
BUG=none
BRANCH=none
TEST=unittest
Change-Id: I8faea3b094c375e4fd1a604a8fe759af88943fdf
Reviewed-on: https://chromium-review.googlesource.com/235792
Reviewed-by: Daniel Ehrenberg <dehrenberg@chromium.org>
Tested-by: Nam Nguyen <namnguyen@chromium.org>
Commit-Queue: Nam Nguyen <namnguyen@chromium.org>
| -rw-r--r-- | cgpt/cgpt_create.c | 32 | ||||
| -rwxr-xr-x | tests/run_cgpt_tests.sh | 6 |
2 files changed, 27 insertions, 11 deletions
diff --git a/cgpt/cgpt_create.c b/cgpt/cgpt_create.c index 64f3f4d2..60e23c96 100644 --- a/cgpt/cgpt_create.c +++ b/cgpt/cgpt_create.c @@ -51,19 +51,29 @@ static int GptCreate(struct drive *drive, CgptCreateParams *params) { h->number_of_entries = TOTAL_ENTRIES_SIZE / h->size_of_entry; if (drive->gpt.flags & GPT_FLAG_EXTERNAL) { // We might have smaller space for the GPT table. Scale accordingly. - size_t half_size_sectors = drive->gpt.gpt_drive_sectors / 2; - if (half_size_sectors < GPT_HEADER_SECTORS) { - Error("Not enough space for a GPT header.\n"); + // + // +------+------------+---------------+-----+--------------+-----------+ + // | PMBR | Prim. Head | Prim. Entries | ... | Sec. Entries | Sec. Head | + // +------+------------+---------------+-----+--------------+-----------+ + // + // Half the size of gpt_drive_sectors must be big enough to hold PMBR + + // GPT Header + Entries Table, though the secondary structures do not + // contain PMBR. + size_t required_headers_size = + (GPT_PMBR_SECTORS + GPT_HEADER_SECTORS) * drive->gpt.sector_bytes; + size_t min_entries_size = MIN_NUMBER_OF_ENTRIES * h->size_of_entry; + size_t required_min_size = required_headers_size + min_entries_size; + size_t half_size = + (drive->gpt.gpt_drive_sectors / 2) * drive->gpt.sector_bytes; + if (half_size < required_min_size) { + Error("Not enough space to store GPT structures. Required %d bytes.\n", + required_min_size * 2); return -1; } - half_size_sectors -= (GPT_HEADER_SECTORS + GPT_PMBR_SECTORS); - size_t half_size = half_size_sectors * drive->gpt.sector_bytes; - if (half_size < (MIN_NUMBER_OF_ENTRIES * h->size_of_entry)) { - Error("Not enough space for minimum number of entries.\n"); - return -1; - } - if (128 > (half_size / h->size_of_entry)) { - h->number_of_entries = half_size / h->size_of_entry; + size_t max_entries = + (half_size - required_headers_size) / h->size_of_entry; + if (h->number_of_entries > max_entries) { + h->number_of_entries = max_entries; } } diff --git a/tests/run_cgpt_tests.sh b/tests/run_cgpt_tests.sh index 7170eef8..5176017a 100755 --- a/tests/run_cgpt_tests.sh +++ b/tests/run_cgpt_tests.sh @@ -291,6 +291,12 @@ $CGPT find $MTD -t kernel ${DEV} >/dev/null # Enable write access again to test boundary in off device storage chmod 600 ${DEV} +# GPT too small +dd if=/dev/zero of=${DEV} bs=5632 count=1 +assert_fail $CGPT create -D 1024 ${DEV} +# GPT is just right for 16 entries (512 + 512 + 16 * 128) * 2 = 6144 +dd if=/dev/zero of=${DEV} bs=6144 count=1 +$CGPT create -D 1024 ${DEV} # Create a small 8K file to simulate Flash NOR section dd if=/dev/zero of=${DEV} bs=8K count=1 # Drive size is not multiple of 512 |