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/* Copyright (c) 2013 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 "sysincludes.h"
#include "cgptlib.h"
#include "cgptlib_internal.h"
#include "crc32.h"
#include "gpt.h"
#include "utility.h"
#include "vboot_api.h"
/**
* Allocate and read GPT data from the drive.
*
* The sector_bytes and gpt_drive_sectors fields should be filled on input. The
* primary and secondary header and entries are filled on output.
*
* Returns 0 if successful, 1 if error.
*/
int AllocAndReadGptData(VbExDiskHandle_t disk_handle, GptData *gptdata)
{
uint64_t max_entries_bytes = MAX_NUMBER_OF_ENTRIES * sizeof(GptEntry);
int primary_valid = 0, secondary_valid = 0;
/* No data to be written yet */
gptdata->modified = 0;
/* Allocate all buffers */
gptdata->primary_header = (uint8_t *)VbExMalloc(gptdata->sector_bytes);
gptdata->secondary_header =
(uint8_t *)VbExMalloc(gptdata->sector_bytes);
gptdata->primary_entries = (uint8_t *)VbExMalloc(max_entries_bytes);
gptdata->secondary_entries = (uint8_t *)VbExMalloc(max_entries_bytes);
if (gptdata->primary_header == NULL ||
gptdata->secondary_header == NULL ||
gptdata->primary_entries == NULL ||
gptdata->secondary_entries == NULL)
return 1;
/* Read primary header from the drive, skipping the protective MBR */
if (0 != VbExDiskRead(disk_handle, 1, 1, gptdata->primary_header))
return 1;
/* Only read primary GPT if the primary header is valid */
GptHeader* primary_header = (GptHeader*)gptdata->primary_header;
if (0 == CheckHeader(primary_header, 0,
gptdata->streaming_drive_sectors,
gptdata->gpt_drive_sectors,
gptdata->flags)) {
primary_valid = 1;
uint64_t entries_bytes = primary_header->number_of_entries
* primary_header->size_of_entry;
uint64_t entries_sectors = entries_bytes
/ gptdata->sector_bytes;
if (0 != VbExDiskRead(disk_handle,
primary_header->entries_lba,
entries_sectors,
gptdata->primary_entries))
return 1;
} else {
VBDEBUG(("Primary GPT header invalid!\n"));
}
/* Read secondary header from the end of the drive */
if (0 != VbExDiskRead(disk_handle, gptdata->gpt_drive_sectors - 1, 1,
gptdata->secondary_header))
return 1;
/* Only read secondary GPT if the secondary header is valid */
GptHeader* secondary_header = (GptHeader*)gptdata->secondary_header;
if (0 == CheckHeader(secondary_header, 1,
gptdata->streaming_drive_sectors,
gptdata->gpt_drive_sectors,
gptdata->flags)) {
secondary_valid = 1;
uint64_t entries_bytes = secondary_header->number_of_entries
* secondary_header->size_of_entry;
uint64_t entries_sectors = entries_bytes
/ gptdata->sector_bytes;
if (0 != VbExDiskRead(disk_handle,
secondary_header->entries_lba,
entries_sectors,
gptdata->secondary_entries))
return 1;
} else {
VBDEBUG(("Secondary GPT header invalid!\n"));
}
/* Return 0 if least one GPT header was valid */
return (primary_valid || secondary_valid) ? 0 : 1;
}
/**
* Write any changes for the GPT data back to the drive, then free the buffers.
*
* Returns 0 if successful, 1 if error.
*/
int WriteAndFreeGptData(VbExDiskHandle_t disk_handle, GptData *gptdata)
{
int legacy = 0;
GptHeader *header = (GptHeader *)gptdata->primary_header;
uint64_t entries_bytes = header->number_of_entries
* header->size_of_entry;
uint64_t entries_sectors = entries_bytes / gptdata->sector_bytes;
int ret = 1;
/*
* TODO(namnguyen): Preserve padding between primary GPT header and
* its entries.
*/
uint64_t entries_lba = GPT_PMBR_SECTORS + GPT_HEADER_SECTORS;
if (gptdata->primary_header) {
GptHeader *h = (GptHeader *)(gptdata->primary_header);
entries_lba = h->entries_lba;
/*
* Avoid even looking at this data if we don't need to. We
* may in fact not have read it from disk if the read failed,
* and this avoids a valgrind complaint.
*/
if (gptdata->modified) {
legacy = !Memcmp(h->signature, GPT_HEADER_SIGNATURE2,
GPT_HEADER_SIGNATURE_SIZE);
}
if (gptdata->modified & GPT_MODIFIED_HEADER1) {
if (legacy) {
VBDEBUG(("Not updating GPT header 1: "
"legacy mode is enabled.\n"));
} else {
VBDEBUG(("Updating GPT header 1\n"));
if (0 != VbExDiskWrite(disk_handle, 1, 1,
gptdata->primary_header))
goto fail;
}
}
}
if (gptdata->primary_entries) {
if (gptdata->modified & GPT_MODIFIED_ENTRIES1) {
if (legacy) {
VBDEBUG(("Not updating GPT entries 1: "
"legacy mode is enabled.\n"));
} else {
VBDEBUG(("Updating GPT entries 1\n"));
if (0 != VbExDiskWrite(disk_handle, entries_lba,
entries_sectors,
gptdata->primary_entries))
goto fail;
}
}
}
entries_lba = (gptdata->gpt_drive_sectors - entries_sectors -
GPT_HEADER_SECTORS);
if (gptdata->secondary_header) {
GptHeader *h = (GptHeader *)(gptdata->secondary_header);
entries_lba = h->entries_lba;
if (gptdata->modified & GPT_MODIFIED_HEADER2) {
VBDEBUG(("Updating GPT entries 2\n"));
if (0 != VbExDiskWrite(disk_handle,
gptdata->gpt_drive_sectors - 1, 1,
gptdata->secondary_header))
goto fail;
}
}
if (gptdata->secondary_entries) {
if (gptdata->modified & GPT_MODIFIED_ENTRIES2) {
VBDEBUG(("Updating GPT header 2\n"));
if (0 != VbExDiskWrite(disk_handle,
entries_lba, entries_sectors,
gptdata->secondary_entries))
goto fail;
}
}
ret = 0;
fail:
/* Avoid leaking memory on disk write failure */
if (gptdata->primary_header)
VbExFree(gptdata->primary_header);
if (gptdata->primary_entries)
VbExFree(gptdata->primary_entries);
if (gptdata->secondary_entries)
VbExFree(gptdata->secondary_entries);
if (gptdata->secondary_header)
VbExFree(gptdata->secondary_header);
/* Success */
return ret;
}
int IsUnusedEntry(const GptEntry *e)
{
static Guid zero = {{{0, 0, 0, 0, 0, {0, 0, 0, 0, 0, 0}}}};
return !Memcmp(&zero, (const uint8_t*)(&e->type), sizeof(zero));
}
/*
* Func: GptGetEntrySize
* Desc: This function returns size(in lba) of a partition represented by
* given GPT entry.
*/
size_t GptGetEntrySizeLba(const GptEntry *e)
{
return (e->ending_lba - e->starting_lba + 1);
}
/*
* Func: GptGetEntrySize
* Desc: This function returns size(in bytes) of a partition represented by
* given GPT entry.
*/
size_t GptGetEntrySizeBytes(const GptData *gpt, const GptEntry *e)
{
return GptGetEntrySizeLba(e) * gpt->sector_bytes;
}
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