/*
gpt.[ch]
Copyright (C) 2000-2001 Dell Computer Corporation <Matt_Domsch@dell.com>
EFI GUID Partition Table handling
Per Intel EFI Specification v1.02
http://developer.intel.com/technology/efi/efi.htm
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
// For TWRP purposes, we'll be opting for version 3 of the GPL
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <inttypes.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include <sys/utsname.h>
#include <asm/byteorder.h>
#include "gpt.h"
#include "gptcrc32.h"
#define BLKGETLASTSECT _IO(0x12,108) /* get last sector of block device */
#define BLKGETSIZE _IO(0x12,96) /* return device size */
#define BLKSSZGET _IO(0x12,104) /* get block device sector size */
#define BLKGETSIZE64 _IOR(0x12,114,uint64_t) /* return device size in bytes (u64 *arg) */
struct blkdev_ioctl_param {
unsigned int block;
size_t content_length;
char * block_contents;
};
static inline int
efi_guidcmp(efi_guid_t left, efi_guid_t right)
{
return memcmp(&left, &right, sizeof (efi_guid_t));
}
static int
get_sector_size(int filedes)
{
int rc, sector_size = 512;
rc = ioctl(filedes, BLKSSZGET, §or_size);
if (rc)
sector_size = 512;
return sector_size;
}
/**
* efi_crc32() - EFI version of crc32 function
* @buf: buffer to calculate crc32 of
* @len - length of buf
*
* Description: Returns EFI-style CRC32 value for @buf
*
* This function uses the little endian Ethernet polynomial
* but seeds the function with ~0, and xor's with ~0 at the end.
* Note, the EFI Specification, v1.02, has a reference to
* Dr. Dobbs Journal, May 1994 (actually it's in May 1992).
*/
static inline uint32_t
efi_crc32(const void *buf, unsigned long len)
{
return (gptcrc32(buf, len, ~0L) ^ ~0L);
}
/**
* is_pmbr_valid(): test Protective MBR for validity
* @mbr: pointer to a legacy mbr structure
*
* Description: Returns 1 if PMBR is valid, 0 otherwise.
* Validity depends on two things:
* 1) MSDOS signature is in the last two bytes of the MBR
* 2) One partition of type 0xEE is found
*/
static int
is_pmbr_valid(legacy_mbr *mbr)
{
int i, found = 0, signature = 0;
if (!mbr)
return 0;
signature = (__le16_to_cpu(mbr->signature) == MSDOS_MBR_SIGNATURE);
for (i = 0; signature && i < 4; i++) {
if (mbr->partition[i].os_type ==
EFI_PMBR_OSTYPE_EFI_GPT) {
found = 1;
break;
}
}
return (signature && found);
}
/**
* kernel_has_blkgetsize64()
*
* Returns: 0 on false, 1 on true
* True means kernel is 2.4.x, x>=18, or
* is 2.5.x, x>4, or
* is > 2.5
*/
static int
kernel_has_blkgetsize64(void)
{
int major=0, minor=0, patch=0, parsed;
int rc;
struct utsname u;
memset(&u, 0, sizeof(u));
rc = uname(&u);
if (rc) return 0;
parsed = sscanf(u.release, "%d.%d.%d", &major, &minor, &patch);
if (parsed < 3) return 0;
if (major > 2) return 1;
if (major == 2 && minor > 5) return 1;
if (major == 2 && minor == 5 && patch >= 4) return 1;
if (major == 2 && minor == 4 && patch >= 18) return 1;
return 0;
}
/************************************************************
* _get_num_sectors
* Requires:
* - filedes is an open file descriptor, suitable for reading
* Modifies: nothing
* Returns:
* Last LBA value on success
* 0 on error
*
* Try getting BLKGETSIZE64 and BLKSSZGET first,
* then BLKGETSIZE if necessary.
* Kernels 2.4.15-2.4.18 and 2.5.0-2.5.3 have a broken BLKGETSIZE64
* which returns the number of 512-byte sectors, not the size of
* the disk in bytes. Fixed in kernels 2.4.18-pre8 and 2.5.4-pre3.
************************************************************/
static uint64_t
_get_num_sectors(int filedes)
{
unsigned long sectors=0;
uint64_t bytes=0;
int rc;
if (kernel_has_blkgetsize64()) {
rc = ioctl(filedes, BLKGETSIZE64, &bytes);
if (!rc)
return bytes / get_sector_size(filedes);
}
rc = ioctl(filedes, BLKGETSIZE, §ors);
if (rc)
return 0;
return sectors;
}
/************************************************************
* last_lba(): return number of last logical block of device
*
* @fd
*
* Description: returns Last LBA value on success, 0 on error.
* Notes: The value st_blocks gives the size of the file
* in 512-byte blocks, which is OK if
* EFI_BLOCK_SIZE_SHIFT == 9.
************************************************************/
static uint64_t
last_lba(int filedes)
{
int rc;
uint64_t sectors = 0;
struct stat s;
memset(&s, 0, sizeof (s));
rc = fstat(filedes, &s);
if (rc == -1) {
fprintf(stderr, "last_lba() could not stat: %s\n",
strerror(errno));
return 0;
}
if (S_ISBLK(s.st_mode)) {
sectors = _get_num_sectors(filedes);
} else {
fprintf(stderr,
"last_lba(): I don't know how to handle files with mode %x\n",
s.st_mode);
sectors = 1;
}
return sectors - 1;
}
static ssize_t
read_lastoddsector(int fd, uint64_t lba __unused, void *buffer, size_t count)
{
int rc;
struct blkdev_ioctl_param ioctl_param;
if (!buffer) return 0;
ioctl_param.block = 0; /* read the last sector */
ioctl_param.content_length = count;
ioctl_param.block_contents = buffer;
rc = ioctl(fd, BLKGETLASTSECT, &ioctl_param);
if (rc == -1) perror("read failed");
return !rc;
}
static ssize_t
read_lba(int fd, uint64_t lba, void *buffer, size_t bytes)
{
int sector_size = get_sector_size(fd);
off_t offset = lba * sector_size;
ssize_t bytesread;
void *aligned;
void *unaligned;
if (bytes % sector_size)
return EINVAL;
unaligned = malloc(bytes+sector_size-1);
aligned = (void *)
(((unsigned long)unaligned + sector_size - 1) &
~(unsigned long)(sector_size-1));
memset(aligned, 0, bytes);
lseek(fd, offset, SEEK_SET);
bytesread = read(fd, aligned, bytes);
memcpy(buffer, aligned, bytesread);
free(unaligned);
/* Kludge. This is necessary to read/write the last
block of an odd-sized disk, until Linux 2.5.x kernel fixes.
This is only used by gpt.c, and only to read
one sector, so we don't have to be fancy.
*/
if (!bytesread && !(last_lba(fd) & 1) && lba == last_lba(fd)) {
bytesread = read_lastoddsector(fd, lba, buffer, bytes);
}
return bytesread;
}
/**
* alloc_read_gpt_entries(): reads partition entries from disk
* @fd is an open file descriptor to the whole disk
* @gpt is a buffer into which the GPT will be put
* Description: Returns ptes on success, NULL on error.
* Allocates space for PTEs based on information found in @gpt.
* Notes: remember to free pte when you're done!
*/
static gpt_entry *
alloc_read_gpt_entries(int fd, gpt_header * gpt)
{
gpt_entry *pte;
size_t count = __le32_to_cpu(gpt->num_partition_entries) *
__le32_to_cpu(gpt->sizeof_partition_entry);
if (!count) return NULL;
pte = (gpt_entry *)malloc(count);
if (!pte)
return NULL;
memset(pte, 0, count);
if (!read_lba(fd, __le64_to_cpu(gpt->partition_entry_lba), pte,
count)) {
free(pte);
return NULL;
}
return pte;
}
/**
* alloc_read_gpt_header(): Allocates GPT header, reads into it from disk
* @fd is an open file descriptor to the whole disk
* @lba is the Logical Block Address of the partition table
*
* Description: returns GPT header on success, NULL on error. Allocates
* and fills a GPT header starting at @ from @bdev.
* Note: remember to free gpt when finished with it.
*/
static gpt_header *
alloc_read_gpt_header(int fd, uint64_t lba)
{
gpt_header *gpt;
gpt = (gpt_header *)
malloc(sizeof (gpt_header));
if (!gpt)
return NULL;
memset(gpt, 0, sizeof (*gpt));
if (!read_lba(fd, lba, gpt, sizeof (gpt_header))) {
free(gpt);
return NULL;
}
return gpt;
}
/**
* is_gpt_valid() - tests one GPT header and PTEs for validity
* @fd is an open file descriptor to the whole disk
* @lba is the logical block address of the GPT header to test
* @gpt is a GPT header ptr, filled on return.
* @ptes is a PTEs ptr, filled on return.
*
* Description: returns 1 if valid, 0 on error.
* If valid, returns pointers to newly allocated GPT header and PTEs.
*/
static int
is_gpt_valid(int fd, uint64_t lba,
gpt_header ** gpt, gpt_entry ** ptes)
{
int rc = 0; /* default to not valid */
uint32_t crc, origcrc;
if (!gpt || !ptes)
return 0;
if (!(*gpt = alloc_read_gpt_header(fd, lba)))
return 0;
/* Check the GUID Partition Table signature */
if (__le64_to_cpu((*gpt)->signature) != GPT_HEADER_SIGNATURE) {
/*
printf("GUID Partition Table Header signature is wrong: %" PRIx64" != %" PRIx64 "\n",
__le64_to_cpu((*gpt)->signature), GUID_PT_HEADER_SIGNATURE);
*/
free(*gpt);
*gpt = NULL;
return rc;
}
/* Check the GUID Partition Table Header CRC */
origcrc = __le32_to_cpu((*gpt)->header_crc32);
(*gpt)->header_crc32 = 0;
crc = efi_crc32(*gpt, __le32_to_cpu((*gpt)->header_size));
if (crc != origcrc) {
// printf( "GPTH CRC check failed, %x != %x.\n", origcrc, crc);
(*gpt)->header_crc32 = __cpu_to_le32(origcrc);
free(*gpt);
*gpt = NULL;
return 0;
}
(*gpt)->header_crc32 = __cpu_to_le32(origcrc);
/* Check that the my_lba entry points to the LBA
* that contains the GPT we read */
if (__le64_to_cpu((*gpt)->my_lba) != lba) {
// printf( "my_lba % PRIx64 "x != lba %"PRIx64 "x.\n", __le64_to_cpu((*gpt)->my_lba), lba);
free(*gpt);
*gpt = NULL;
return 0;
}
if (!(*ptes = alloc_read_gpt_entries(fd, *gpt))) {
free(*gpt);
*gpt = NULL;
return 0;
}
/* Check the GUID Partition Entry Array CRC */
crc = efi_crc32(*ptes,
__le32_to_cpu((*gpt)->num_partition_entries) *
__le32_to_cpu((*gpt)->sizeof_partition_entry));
if (crc != __le32_to_cpu((*gpt)->partition_entry_array_crc32)) {
// printf("GUID Partitition Entry Array CRC check failed.\n");
free(*gpt);
*gpt = NULL;
free(*ptes);
*ptes = NULL;
return 0;
}
/* We're done, all's well */
return 1;
}
/**
* compare_gpts() - Search disk for valid GPT headers and PTEs
* @pgpt is the primary GPT header
* @agpt is the alternate GPT header
* @lastlba is the last LBA number
* Description: Returns nothing. Sanity checks pgpt and agpt fields
* and prints warnings on discrepancies.
*
*/
static void
compare_gpts(gpt_header *pgpt, gpt_header *agpt, uint64_t lastlba)
{
int error_found = 0;
if (!pgpt || !agpt)
return;
if (__le64_to_cpu(pgpt->my_lba) != __le64_to_cpu(agpt->alternate_lba)) {
fprintf(stderr,
"GPT:Primary header LBA != Alt. header alternate_lba\n");
fprintf(stderr, "GPT:0x%" PRIx64 " != 0x%" PRIx64 "\n",
__le64_to_cpu(pgpt->my_lba),
__le64_to_cpu(agpt->alternate_lba));
error_found++;
}
if (__le64_to_cpu(pgpt->alternate_lba) != __le64_to_cpu(agpt->my_lba)) {
fprintf(stderr,
"GPT:Primary header alternate_lba != Alt. header my_lba\n");
fprintf(stderr, "GPT:0x%" PRIx64 " != 0x%" PRIx64 "\n",
__le64_to_cpu(pgpt->alternate_lba),
__le64_to_cpu(agpt->my_lba));
error_found++;
}
if (__le64_to_cpu(pgpt->first_usable_lba) !=
__le64_to_cpu(agpt->first_usable_lba)) {
fprintf(stderr, "GPT:first_usable_lbas don't match.\n");
fprintf(stderr, "GPT:0x%" PRIx64 " != 0x%" PRIx64 "\n",
__le64_to_cpu(pgpt->first_usable_lba),
__le64_to_cpu(agpt->first_usable_lba));
error_found++;
}
if (__le64_to_cpu(pgpt->last_usable_lba) !=
__le64_to_cpu(agpt->last_usable_lba)) {
fprintf(stderr, "GPT:last_usable_lbas don't match.\n");
fprintf(stderr, "GPT:0x%" PRIx64 " != 0x%" PRIx64 "\n",
__le64_to_cpu(pgpt->last_usable_lba),
__le64_to_cpu(agpt->last_usable_lba));
error_found++;
}
if (efi_guidcmp(pgpt->disk_guid, agpt->disk_guid)) {
fprintf(stderr, "GPT:disk_guids don't match.\n");
error_found++;
}
if (__le32_to_cpu(pgpt->num_partition_entries) !=
__le32_to_cpu(agpt->num_partition_entries)) {
fprintf(stderr, "GPT:num_partition_entries don't match: "
"0x%x != 0x%x\n",
__le32_to_cpu(pgpt->num_partition_entries),
__le32_to_cpu(agpt->num_partition_entries));
error_found++;
}
if (__le32_to_cpu(pgpt->sizeof_partition_entry) !=
__le32_to_cpu(agpt->sizeof_partition_entry)) {
fprintf(stderr,
"GPT:sizeof_partition_entry values don't match: "
"0x%x != 0x%x\n",
__le32_to_cpu(pgpt->sizeof_partition_entry),
__le32_to_cpu(agpt->sizeof_partition_entry));
error_found++;
}
if (__le32_to_cpu(pgpt->partition_entry_array_crc32) !=
__le32_to_cpu(agpt->partition_entry_array_crc32)) {
fprintf(stderr,
"GPT:partition_entry_array_crc32 values don't match: "
"0x%x != 0x%x\n",
__le32_to_cpu(pgpt->partition_entry_array_crc32),
__le32_to_cpu(agpt->partition_entry_array_crc32));
error_found++;
}
if (__le64_to_cpu(pgpt->alternate_lba) != lastlba) {
fprintf(stderr,
"GPT:Primary header thinks Alt. header is not at the end of the disk.\n");
fprintf(stderr, "GPT:0x%" PRIx64 " != 0x%" PRIx64 "\n",
__le64_to_cpu(pgpt->alternate_lba), lastlba);
error_found++;
}
if (__le64_to_cpu(agpt->my_lba) != lastlba) {
fprintf(stderr,
"GPT:Alternate GPT header not at the end of the disk.\n");
fprintf(stderr, "GPT:0x%" PRIx64 " != 0x%" PRIx64 "\n",
__le64_to_cpu(agpt->my_lba), lastlba);
error_found++;
}
if (error_found)
fprintf(stderr,
"GPT: Use GNU Parted to correct GPT errors.\n");
return;
}
/**
* find_valid_gpt() - Search disk for valid GPT headers and PTEs
* @fd is an open file descriptor to the whole disk
* @gpt is a GPT header ptr, filled on return.
* @ptes is a PTEs ptr, filled on return.
* Description: Returns 1 if valid, 0 on error.
* If valid, returns pointers to newly allocated GPT header and PTEs.
* Validity depends on finding either the Primary GPT header and PTEs valid,
* or the Alternate GPT header and PTEs valid, and the PMBR valid.
*/
static int
find_valid_gpt(int fd, gpt_header ** gpt, gpt_entry ** ptes)
{
int good_pgpt = 0, good_agpt = 0, good_pmbr = 0;
gpt_header *pgpt = NULL, *agpt = NULL;
gpt_entry *pptes = NULL, *aptes = NULL;
legacy_mbr *legacymbr = NULL;
uint64_t lastlba;
if (!gpt || !ptes)
return 0;
lastlba = last_lba(fd);
good_pgpt = is_gpt_valid(fd, GPT_PRIMARY_PARTITION_TABLE_LBA,
&pgpt, &pptes);
if (good_pgpt) {
good_agpt = is_gpt_valid(fd,
__le64_to_cpu(pgpt->alternate_lba),
&agpt, &aptes);
if (!good_agpt) {
good_agpt = is_gpt_valid(fd, lastlba,
&agpt, &aptes);
}
}
else {
good_agpt = is_gpt_valid(fd, lastlba,
&agpt, &aptes);
}
/* The obviously unsuccessful case */
if (!good_pgpt && !good_agpt) {
goto fail;
}
/* This will be added to the EFI Spec. per Intel after v1.02. */
legacymbr = malloc(sizeof (*legacymbr));
if (legacymbr) {
memset(legacymbr, 0, sizeof (*legacymbr));
read_lba(fd, 0, (uint8_t *) legacymbr,
sizeof (*legacymbr));
good_pmbr = is_pmbr_valid(legacymbr);
free(legacymbr);
legacymbr=NULL;
}
/* Failure due to bad PMBR */
if ((good_pgpt || good_agpt) && !good_pmbr) {
fprintf(stderr,
" Warning: Disk has a valid GPT signature "
"but invalid PMBR.\n"
" Assuming this disk is *not* a GPT disk anymore.\n"
" Use gpt kernel option to override. "
"Use GNU Parted to correct disk.\n");
goto fail;
}
/* Would fail due to bad PMBR, but force GPT anyhow */
if ((good_pgpt || good_agpt) && !good_pmbr) {
fprintf(stderr,
" Warning: Disk has a valid GPT signature but "
"invalid PMBR.\n"
" Use GNU Parted to correct disk.\n"
" gpt option taken, disk treated as GPT.\n");
}
compare_gpts(pgpt, agpt, lastlba);
/* The good cases */
if (good_pgpt && (good_pmbr)) {
*gpt = pgpt;
*ptes = pptes;
if (agpt) { free(agpt); agpt = NULL; }
if (aptes) { free(aptes); aptes = NULL; }
if (!good_agpt) {
fprintf(stderr,
"Alternate GPT is invalid, "
"using primary GPT.\n");
}
return 1;
}
else if (good_agpt && (good_pmbr)) {
*gpt = agpt;
*ptes = aptes;
if (pgpt) { free(pgpt); pgpt = NULL; }
if (pptes) { free(pptes); pptes = NULL; }
fprintf(stderr,
"Primary GPT is invalid, using alternate GPT.\n");
return 1;
}
fail:
if (pgpt) { free(pgpt); pgpt=NULL; }
if (agpt) { free(agpt); agpt=NULL; }
if (pptes) { free(pptes); pptes=NULL; }
if (aptes) { free(aptes); aptes=NULL; }
*gpt = NULL;
*ptes = NULL;
return 0;
}
void guid_to_ascii(const char *guid, char *s)
{
uint32_t p1;
uint16_t p2;
uint16_t p3;
unsigned char p4[8];
memcpy(&p1, guid + 0, 4);
memcpy(&p2, guid + 4, 2);
memcpy(&p3, guid + 6, 2);
memcpy(p4, guid + 8, 8);
sprintf(s, "%08x%04x%04x%02x%02x%02x%02x%02x%02x%02x%02x",
p1, p2, p3, p4[0], p4[1],
p4[2], p4[3], p4[4], p4[5], p4[6], p4[7]);
}
/************************************************************
* gpt_disk_get_partition_info()
* Requires:
* - open file descriptor fd
* - start, size, signature, mbr_type, signature_type
* Modifies: all these
* Returns:
* 0 on success
* non-zero on failure
*
************************************************************/
int
gpt_disk_get_partition_info(int fd, uint32_t num,
char *type, char *part)
{
gpt_header *gpt = NULL;
gpt_entry *ptes = NULL, *p;
if (!find_valid_gpt(fd, &gpt, &ptes))
return 1;
if (num > 0 && num <= __le32_to_cpu(gpt->num_partition_entries)) {
p = &ptes[num - 1];
guid_to_ascii((char*)&p->partition_type_guid, type);
guid_to_ascii((char*)&p->unique_partition_guid, part);
} else {
fprintf (stderr,"partition %d is not valid\n", num);
return 1;
}
return 0;
}
/*
* Overrides for Emacs so that we follow Linus's tabbing style.
* Emacs will notice this stuff at the end of the file and automatically
* adjust the settings for this buffer only. This must remain at the end
* of the file.
* ---------------------------------------------------------------------------
* Local variables:
* c-indent-level: 4
* c-brace-imaginary-offset: 0
* c-brace-offset: -4
* c-argdecl-indent: 4
* c-label-offset: -4
* c-continued-statement-offset: 4
* c-continued-brace-offset: 0
* indent-tabs-mode: nil
* tab-width: 8
* End:
*/
