511 lines
15 KiB
C
511 lines
15 KiB
C
/*
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gpt.[ch]
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Copyright (C) 2000-2001 Dell Computer Corporation <Matt_Domsch@dell.com>
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EFI GUID Partition Table handling
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Per Intel EFI Specification v1.02
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http://developer.intel.com/technology/efi/efi.htm
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#include <stdio.h>
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#include <string.h>
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#include <stdlib.h>
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#include <inttypes.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <unistd.h>
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#include <errno.h>
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#include "blkdev.h"
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#include "crc32.h"
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#include "gpt.h"
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#include "partx.h"
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#include "bitops.h"
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static inline uint32_t
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efi_crc32(const void *buf, unsigned long len)
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{
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return (crc32(~0L, buf, len) ^ ~0L);
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}
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/**
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* is_pmbr_valid(): test Protective MBR for validity
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* @mbr: pointer to a legacy mbr structure
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*
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* Description: Returns 1 if PMBR is valid, 0 otherwise.
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* Validity depends on two things:
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* 1) MSDOS signature is in the last two bytes of the MBR
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* 2) One partition of type 0xEE is found
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*/
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static int
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is_pmbr_valid(legacy_mbr *mbr)
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{
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int i, found = 0, signature = 0;
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if (!mbr)
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return 0;
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signature = (le16_to_cpu(mbr->signature) == MSDOS_MBR_SIGNATURE);
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for (i = 0; signature && i < 4; i++) {
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if (mbr->partition[i].sys_type ==
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EFI_PMBR_OSTYPE_EFI_GPT) {
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found = 1;
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break;
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}
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}
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return (signature && found);
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}
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static int
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get_sector_size (int fd)
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{
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int sector_size;
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if (blkdev_get_sector_size(fd, §or_size) == -1)
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return DEFAULT_SECTOR_SIZE;
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return sector_size;
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}
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static uint64_t
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get_num_sectors(int fd)
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{
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unsigned long long bytes=0;
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if (blkdev_get_size(fd, &bytes) == -1)
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return 0;
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return bytes / get_sector_size(fd);
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}
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static uint64_t
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last_lba(int filedes)
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{
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int rc;
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uint64_t sectors = 0;
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struct stat s;
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memset(&s, 0, sizeof (s));
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rc = fstat(filedes, &s);
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if (rc == -1) {
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fprintf(stderr, "last_lba() could not stat: %s\n",
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strerror(errno));
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return 0;
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}
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if (S_ISBLK(s.st_mode)) {
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sectors = get_num_sectors(filedes);
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} else {
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fprintf(stderr,
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"last_lba(): I don't know how to handle files with mode %x\n",
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s.st_mode);
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sectors = 1;
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}
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return sectors - 1;
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}
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static ssize_t
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read_lba(int fd, uint64_t lba, void *buffer, size_t bytes)
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{
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int sector_size = get_sector_size(fd);
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off_t offset = lba * sector_size;
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lseek(fd, offset, SEEK_SET);
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return read(fd, buffer, bytes);
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}
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/**
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* alloc_read_gpt_entries(): reads partition entries from disk
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* @fd is an open file descriptor to the whole disk
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* @gpt is a buffer into which the GPT will be put
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* Description: Returns ptes on success, NULL on error.
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* Allocates space for PTEs based on information found in @gpt.
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* Notes: remember to free pte when you're done!
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*/
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static gpt_entry *
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alloc_read_gpt_entries(int fd, gpt_header * gpt)
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{
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gpt_entry *pte;
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size_t count = le32_to_cpu(gpt->num_partition_entries) *
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le32_to_cpu(gpt->sizeof_partition_entry);
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if (!count) return NULL;
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pte = (gpt_entry *)malloc(count);
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if (!pte)
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return NULL;
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memset(pte, 0, count);
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if (!read_lba(fd, le64_to_cpu(gpt->partition_entry_lba), pte,
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count)) {
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free(pte);
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return NULL;
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}
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return pte;
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}
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/**
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* alloc_read_gpt_header(): Allocates GPT header, reads into it from disk
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* @fd is an open file descriptor to the whole disk
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* @lba is the Logical Block Address of the partition table
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*
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* Description: returns GPT header on success, NULL on error. Allocates
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* and fills a GPT header starting at @ from @bdev.
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* Note: remember to free gpt when finished with it.
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*/
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static gpt_header *
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alloc_read_gpt_header(int fd, uint64_t lba)
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{
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gpt_header *gpt;
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gpt = (gpt_header *)
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malloc(sizeof (gpt_header));
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if (!gpt)
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return NULL;
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memset(gpt, 0, sizeof (*gpt));
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if (!read_lba(fd, lba, gpt, sizeof (gpt_header))) {
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free(gpt);
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return NULL;
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}
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return gpt;
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}
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/**
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* is_gpt_valid() - tests one GPT header and PTEs for validity
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* @fd is an open file descriptor to the whole disk
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* @lba is the logical block address of the GPT header to test
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* @gpt is a GPT header ptr, filled on return.
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* @ptes is a PTEs ptr, filled on return.
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*
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* Description: returns 1 if valid, 0 on error.
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* If valid, returns pointers to newly allocated GPT header and PTEs.
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*/
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static int
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is_gpt_valid(int fd, uint64_t lba,
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gpt_header ** gpt, gpt_entry ** ptes)
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{
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int rc = 0; /* default to not valid */
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uint32_t crc, origcrc;
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if (!gpt || !ptes)
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return 0;
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if (!(*gpt = alloc_read_gpt_header(fd, lba)))
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return 0;
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/* Check the GUID Partition Table signature */
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if (le64_to_cpu((*gpt)->signature) != GPT_HEADER_SIGNATURE) {
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/*
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printf("GUID Partition Table Header signature is wrong: %" PRIx64" != %" PRIx64 "\n",
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le64_to_cpu((*gpt)->signature), GUID_PT_HEADER_SIGNATURE);
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*/
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free(*gpt);
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*gpt = NULL;
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return rc;
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}
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/* Check the GUID Partition Table Header CRC */
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origcrc = le32_to_cpu((*gpt)->header_crc32);
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(*gpt)->header_crc32 = 0;
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crc = efi_crc32(*gpt, le32_to_cpu((*gpt)->header_size));
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if (crc != origcrc) {
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/* printf( "GPTH CRC check failed, %x != %x.\n", origcrc, crc); */
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(*gpt)->header_crc32 = cpu_to_le32(origcrc);
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free(*gpt);
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*gpt = NULL;
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return 0;
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}
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(*gpt)->header_crc32 = cpu_to_le32(origcrc);
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/* Check that the my_lba entry points to the LBA
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* that contains the GPT we read */
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if (le64_to_cpu((*gpt)->my_lba) != lba) {
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/* printf( "my_lba % PRIx64 "x != lba %"PRIx64 "x.\n", le64_to_cpu((*gpt)->my_lba), lba); */
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free(*gpt);
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*gpt = NULL;
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return 0;
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}
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if (!(*ptes = alloc_read_gpt_entries(fd, *gpt))) {
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free(*gpt);
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*gpt = NULL;
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return 0;
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}
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/* Check the GUID Partition Entry Array CRC */
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crc = efi_crc32(*ptes,
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le32_to_cpu((*gpt)->num_partition_entries) *
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le32_to_cpu((*gpt)->sizeof_partition_entry));
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if (crc != le32_to_cpu((*gpt)->partition_entry_array_crc32)) {
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/* printf("GUID Partitition Entry Array CRC check failed.\n"); */
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free(*gpt);
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*gpt = NULL;
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free(*ptes);
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*ptes = NULL;
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return 0;
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}
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/* We're done, all's well */
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return 1;
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}
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/**
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* compare_gpts() - Search disk for valid GPT headers and PTEs
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* @pgpt is the primary GPT header
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* @agpt is the alternate GPT header
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* @lastlba is the last LBA number
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* Description: Returns nothing. Sanity checks pgpt and agpt fields
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* and prints warnings on discrepancies.
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*
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*/
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static void
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compare_gpts(gpt_header *pgpt, gpt_header *agpt, uint64_t lastlba)
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{
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int error_found = 0;
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if (!pgpt || !agpt)
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return;
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if (le64_to_cpu(pgpt->my_lba) != le64_to_cpu(agpt->alternate_lba)) {
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fprintf(stderr,
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"GPT:Primary header LBA != Alt. header alternate_lba\n");
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fprintf(stderr, "GPT:%" PRIx64 "x != %" PRIx64 "x\n",
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le64_to_cpu(pgpt->my_lba),
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le64_to_cpu(agpt->alternate_lba));
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error_found++;
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}
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if (le64_to_cpu(pgpt->alternate_lba) != le64_to_cpu(agpt->my_lba)) {
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fprintf(stderr,
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"GPT:Primary header alternate_lba != Alt. header my_lba\n");
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fprintf(stderr, "GPT:%" PRIx64 " != %" PRIx64 "\n",
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le64_to_cpu(pgpt->alternate_lba),
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le64_to_cpu(agpt->my_lba));
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error_found++;
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}
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if (le64_to_cpu(pgpt->first_usable_lba) !=
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le64_to_cpu(agpt->first_usable_lba)) {
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fprintf(stderr, "GPT:first_usable_lbas don't match.\n");
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fprintf(stderr, "GPT:%" PRIx64 " != %" PRIx64 "\n",
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le64_to_cpu(pgpt->first_usable_lba),
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le64_to_cpu(agpt->first_usable_lba));
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error_found++;
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}
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if (le64_to_cpu(pgpt->last_usable_lba) !=
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le64_to_cpu(agpt->last_usable_lba)) {
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fprintf(stderr, "GPT:last_usable_lbas don't match.\n");
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fprintf(stderr, "GPT:%" PRIx64 " != %" PRIx64 "\n",
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le64_to_cpu(pgpt->last_usable_lba),
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le64_to_cpu(agpt->last_usable_lba));
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error_found++;
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}
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if (efi_guidcmp(pgpt->disk_guid, agpt->disk_guid)) {
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fprintf(stderr, "GPT:disk_guids don't match.\n");
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error_found++;
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}
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if (le32_to_cpu(pgpt->num_partition_entries) !=
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le32_to_cpu(agpt->num_partition_entries)) {
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fprintf(stderr, "GPT:num_partition_entries don't match: "
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"0x%x != 0x%x\n",
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le32_to_cpu(pgpt->num_partition_entries),
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le32_to_cpu(agpt->num_partition_entries));
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error_found++;
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}
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if (le32_to_cpu(pgpt->sizeof_partition_entry) !=
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le32_to_cpu(agpt->sizeof_partition_entry)) {
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fprintf(stderr,
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"GPT:sizeof_partition_entry values don't match: "
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"0x%x != 0x%x\n",
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le32_to_cpu(pgpt->sizeof_partition_entry),
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le32_to_cpu(agpt->sizeof_partition_entry));
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error_found++;
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}
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if (le32_to_cpu(pgpt->partition_entry_array_crc32) !=
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le32_to_cpu(agpt->partition_entry_array_crc32)) {
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fprintf(stderr,
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"GPT:partition_entry_array_crc32 values don't match: "
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"0x%x != 0x%x\n",
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le32_to_cpu(pgpt->partition_entry_array_crc32),
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le32_to_cpu(agpt->partition_entry_array_crc32));
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error_found++;
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}
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if (le64_to_cpu(pgpt->alternate_lba) != lastlba) {
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fprintf(stderr,
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"GPT:Primary header thinks Alt. header is not at the end of the disk.\n");
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fprintf(stderr, "GPT:%" PRIx64 " != %" PRIx64 "\n",
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le64_to_cpu(pgpt->alternate_lba), lastlba);
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error_found++;
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}
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if (le64_to_cpu(agpt->my_lba) != lastlba) {
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fprintf(stderr,
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"GPT:Alternate GPT header not at the end of the disk.\n");
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fprintf(stderr, "GPT:%" PRIx64 " != %" PRIx64 "\n",
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le64_to_cpu(agpt->my_lba), lastlba);
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error_found++;
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}
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if (error_found)
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fprintf(stderr,
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"GPT: Use GNU Parted to correct GPT errors.\n");
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return;
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}
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/**
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* find_valid_gpt() - Search disk for valid GPT headers and PTEs
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* @fd is an open file descriptor to the whole disk
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* @gpt is a GPT header ptr, filled on return.
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* @ptes is a PTEs ptr, filled on return.
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* Description: Returns 1 if valid, 0 on error.
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* If valid, returns pointers to newly allocated GPT header and PTEs.
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* Validity depends on finding either the Primary GPT header and PTEs valid,
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* or the Alternate GPT header and PTEs valid, and the PMBR valid.
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*/
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static int
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find_valid_gpt(int fd, gpt_header ** gpt, gpt_entry ** ptes)
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{
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extern int force_gpt;
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int good_pgpt = 0, good_agpt = 0, good_pmbr = 0;
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gpt_header *pgpt = NULL, *agpt = NULL;
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gpt_entry *pptes = NULL, *aptes = NULL;
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legacy_mbr *legacymbr = NULL;
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uint64_t lastlba;
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if (!gpt || !ptes)
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return 0;
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lastlba = last_lba(fd);
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good_pgpt = is_gpt_valid(fd, GPT_PRIMARY_PARTITION_TABLE_LBA,
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&pgpt, &pptes);
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if (good_pgpt) {
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good_agpt = is_gpt_valid(fd,
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le64_to_cpu(pgpt->alternate_lba),
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&agpt, &aptes);
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if (!good_agpt) {
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good_agpt = is_gpt_valid(fd, lastlba,
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&agpt, &aptes);
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}
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}
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else {
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good_agpt = is_gpt_valid(fd, lastlba,
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&agpt, &aptes);
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}
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/* The obviously unsuccessful case */
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if (!good_pgpt && !good_agpt) {
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goto fail;
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}
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/* This will be added to the EFI Spec. per Intel after v1.02. */
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legacymbr = malloc(sizeof (*legacymbr));
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if (legacymbr) {
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memset(legacymbr, 0, sizeof (*legacymbr));
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read_lba(fd, 0, (uint8_t *) legacymbr,
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sizeof (*legacymbr));
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good_pmbr = is_pmbr_valid(legacymbr);
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free(legacymbr);
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legacymbr=NULL;
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}
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/* Failure due to bad PMBR */
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if ((good_pgpt || good_agpt) && !good_pmbr && !force_gpt) {
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fprintf(stderr,
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" Warning: Disk has a valid GPT signature "
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"but invalid PMBR.\n"
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" Assuming this disk is *not* a GPT disk anymore.\n"
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" Use gpt kernel option to override. "
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"Use GNU Parted to correct disk.\n");
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goto fail;
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}
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/* Would fail due to bad PMBR, but force GPT anyhow */
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if ((good_pgpt || good_agpt) && !good_pmbr && force_gpt) {
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fprintf(stderr,
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" Warning: Disk has a valid GPT signature but "
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"invalid PMBR.\n"
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" Use GNU Parted to correct disk.\n"
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" gpt option taken, disk treated as GPT.\n");
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}
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compare_gpts(pgpt, agpt, lastlba);
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/* The good cases */
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if (good_pgpt && (good_pmbr || force_gpt)) {
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*gpt = pgpt;
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*ptes = pptes;
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if (agpt) { free(agpt); agpt = NULL; }
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if (aptes) { free(aptes); aptes = NULL; }
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if (!good_agpt) {
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fprintf(stderr,
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"Alternate GPT is invalid, "
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"using primary GPT.\n");
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}
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return 1;
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}
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else if (good_agpt && (good_pmbr || force_gpt)) {
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*gpt = agpt;
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*ptes = aptes;
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if (pgpt) { free(pgpt); pgpt = NULL; }
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if (pptes) { free(pptes); pptes = NULL; }
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fprintf(stderr,
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"Primary GPT is invalid, using alternate GPT.\n");
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return 1;
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}
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fail:
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if (pgpt) { free(pgpt); pgpt=NULL; }
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if (agpt) { free(agpt); agpt=NULL; }
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if (pptes) { free(pptes); pptes=NULL; }
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if (aptes) { free(aptes); aptes=NULL; }
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*gpt = NULL;
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*ptes = NULL;
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return 0;
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}
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/**
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* read_gpt_pt()
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* @fd
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* @all - slice with start/size of whole disk
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*
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* 0 if this isn't our partition table
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* number of partitions if successful
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*
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*/
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int
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read_gpt_pt (int fd, struct slice all, struct slice *sp, int ns)
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{
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gpt_header *gpt = NULL;
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gpt_entry *ptes = NULL;
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uint32_t i;
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int n = 0;
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int last_used_index=-1;
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if (!find_valid_gpt (fd, &gpt, &ptes) || !gpt || !ptes) {
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free (gpt);
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free (ptes);
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return 0;
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}
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for (i = 0; i < le32_to_cpu(gpt->num_partition_entries) && i < ns; i++) {
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if (!efi_guidcmp (NULL_GUID, ptes[i].partition_type_guid)) {
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sp[n].start = 0;
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sp[n].size = 0;
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n++;
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} else {
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sp[n].start = le64_to_cpu(ptes[i].starting_lba);
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sp[n].size = le64_to_cpu(ptes[i].ending_lba) -
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le64_to_cpu(ptes[i].starting_lba) + 1;
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last_used_index=n;
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n++;
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}
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}
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free (ptes);
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free (gpt);
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return last_used_index+1;
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}
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