diff options
| -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 |