cgpt: Support non-standard (smaller) entries table
The standard says that entries table must be at least 16384 bytes. On
some of our devices, the NOR section is only 8 KiB and used to store
both primary and secondary tables. On this device, we can only store 24
entries.
Therefore, this CL adds support for non-standard entry table. It adjusts
the MIN_NUMBER_OF_ENTRIES to 16, and replaces GPT_ENTRIES_SECTORS with
CalculateEntriesSectors.
BUG=chromium:441812
BRANCH=none
TEST=unittest
Change-Id: I6b85b35ce5612c7abb22142f8252bd0d45b676c5
Reviewed-on: https://chromium-review.googlesource.com/234996
Reviewed-by: Bill Richardson <wfrichar@chromium.org>
Commit-Queue: Nam Nguyen <namnguyen@chromium.org>
Tested-by: Nam Nguyen <namnguyen@chromium.org>
diff --git a/cgpt/cgpt_create.c b/cgpt/cgpt_create.c
index 2265c8f..64f3f4d 100644
--- a/cgpt/cgpt_create.c
+++ b/cgpt/cgpt_create.c
@@ -29,10 +29,6 @@
drive->gpt.sector_bytes * GPT_HEADER_SECTORS);
AllocAndClear(&drive->gpt.secondary_header,
drive->gpt.sector_bytes * GPT_HEADER_SECTORS);
- AllocAndClear(&drive->gpt.primary_entries,
- drive->gpt.sector_bytes * GPT_ENTRIES_SECTORS);
- AllocAndClear(&drive->gpt.secondary_entries,
- drive->gpt.sector_bytes * GPT_ENTRIES_SECTORS);
drive->gpt.modified |= (GPT_MODIFIED_HEADER1 | GPT_MODIFIED_ENTRIES1 |
GPT_MODIFIED_HEADER2 | GPT_MODIFIED_ENTRIES2);
@@ -45,21 +41,12 @@
h->size = sizeof(GptHeader);
h->my_lba = GPT_PMBR_SECTORS; /* The second sector on drive. */
h->alternate_lba = drive->gpt.gpt_drive_sectors - GPT_HEADER_SECTORS;
- h->entries_lba = h->my_lba + GPT_HEADER_SECTORS;
- if (!(drive->gpt.flags & GPT_FLAG_EXTERNAL)) {
- h->entries_lba += params->padding;
- h->first_usable_lba = h->entries_lba + GPT_ENTRIES_SECTORS;
- h->last_usable_lba = (drive->gpt.streaming_drive_sectors -
- GPT_HEADER_SECTORS -
- GPT_ENTRIES_SECTORS - 1);
- } else {
- h->first_usable_lba = params->padding;
- h->last_usable_lba = (drive->gpt.streaming_drive_sectors - 1);
- }
if (CGPT_OK != GenerateGuid(&h->disk_uuid)) {
Error("Unable to generate new GUID.\n");
return -1;
}
+
+ /* Calculate number of entries */
h->size_of_entry = sizeof(GptEntry);
h->number_of_entries = TOTAL_ENTRIES_SIZE / h->size_of_entry;
if (drive->gpt.flags & GPT_FLAG_EXTERNAL) {
@@ -69,7 +56,7 @@
Error("Not enough space for a GPT header.\n");
return -1;
}
- half_size_sectors -= GPT_HEADER_SECTORS;
+ 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");
@@ -80,6 +67,22 @@
}
}
+ /* Then use number of entries to calculate entries_lba. */
+ h->entries_lba = h->my_lba + GPT_HEADER_SECTORS;
+ if (!(drive->gpt.flags & GPT_FLAG_EXTERNAL)) {
+ h->entries_lba += params->padding;
+ h->first_usable_lba = h->entries_lba + CalculateEntriesSectors(h);
+ h->last_usable_lba = (drive->gpt.streaming_drive_sectors - GPT_HEADER_SECTORS -
+ CalculateEntriesSectors(h) - 1);
+ } else {
+ h->first_usable_lba = params->padding;
+ h->last_usable_lba = (drive->gpt.streaming_drive_sectors - 1);
+ }
+
+ size_t entries_size = h->number_of_entries * h->size_of_entry;
+ AllocAndClear(&drive->gpt.primary_entries, entries_size);
+ AllocAndClear(&drive->gpt.secondary_entries, entries_size);
+
// Copy to secondary
RepairHeader(&drive->gpt, MASK_PRIMARY);