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// Copyright (c) 2012 The Chromium OS Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include <string.h>
#include "cgpt.h"
#include "cgptlib_internal.h"
#include "vboot_host.h"
static void AllocAndClear(uint8_t **buf, uint64_t size) {
if (*buf) {
memset(*buf, 0, size);
} else {
*buf = calloc(1, size);
if (!*buf) {
Error("Cannot allocate %u bytes.\n", size);
abort();
}
}
}
static int GptCreate(struct drive *drive, CgptCreateParams *params) {
// Allocate and/or erase the data.
// We cannot assume the GPT headers or entry arrays have been allocated
// by GptLoad() because those fields might have failed validation checks.
AllocAndClear(&drive->gpt.primary_header,
drive->gpt.sector_bytes * GPT_HEADER_SECTORS);
AllocAndClear(&drive->gpt.secondary_header,
drive->gpt.sector_bytes * GPT_HEADER_SECTORS);
drive->gpt.modified |= (GPT_MODIFIED_HEADER1 | GPT_MODIFIED_ENTRIES1 |
GPT_MODIFIED_HEADER2 | GPT_MODIFIED_ENTRIES2);
// Initialize a blank set
if (!params->zap) {
GptHeader *h = (GptHeader *)drive->gpt.primary_header;
memcpy(h->signature, GPT_HEADER_SIGNATURE, GPT_HEADER_SIGNATURE_SIZE);
h->revision = GPT_HEADER_REVISION;
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;
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 = MAX_NUMBER_OF_ENTRIES;
if (drive->gpt.flags & GPT_FLAG_EXTERNAL) {
// We might have smaller space for the GPT table. Scale accordingly.
//
// +------+------------+---------------+-----+--------------+-----------+
// | 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;
}
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;
}
}
/* 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);
UpdateCrc(&drive->gpt);
}
return 0;
}
int CgptCreate(CgptCreateParams *params) {
struct drive drive;
if (params == NULL)
return CGPT_FAILED;
if (CGPT_OK != DriveOpen(params->drive_name, &drive, O_RDWR,
params->drive_size))
return CGPT_FAILED;
if (GptCreate(&drive, params))
goto bad;
// Write it all out
return DriveClose(&drive, 1);
bad:
DriveClose(&drive, 0);
return CGPT_FAILED;
}
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