diff options
Diffstat (limited to 'firmware/lib/gpt_misc.c')
| -rw-r--r-- | firmware/lib/gpt_misc.c | 181 |
1 files changed, 181 insertions, 0 deletions
diff --git a/firmware/lib/gpt_misc.c b/firmware/lib/gpt_misc.c new file mode 100644 index 00000000..d00d6b2e --- /dev/null +++ b/firmware/lib/gpt_misc.c @@ -0,0 +1,181 @@ +/* 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 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 entries_sectors = TOTAL_ENTRIES_SIZE / gptdata->sector_bytes; + 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(TOTAL_ENTRIES_SIZE); + gptdata->secondary_entries = (uint8_t *)VbExMalloc(TOTAL_ENTRIES_SIZE); + + 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->drive_sectors)) { + primary_valid = 1; + 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->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->drive_sectors)) { + secondary_valid = 1; + 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; + uint64_t entries_sectors = TOTAL_ENTRIES_SIZE / 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->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->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; +} + |