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incubator-nuttx/fs/partition/fs_gpt.c

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/****************************************************************************
* fs/partition/fs_gpt.c
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <ctype.h>
#include <debug.h>
#include <endian.h>
#include <inttypes.h>
#include <sys/param.h>
#include <nuttx/crc32.h>
#include <nuttx/kmalloc.h>
#include "partition.h"
#include "fs_heap.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
#define GPT_BLOCK_SIZE 512
#define GPT_HEADER_SIGNATURE 0x5452415020494645ull
#define GPT_PARTNAME_MAX_SIZE (72 / sizeof(uint16_t))
#define GPT_LBA_TO_BLOCK(lba, blk) ((le64toh(lba) * 512 + (blk) - 1) / (blk))
/****************************************************************************
* Private Types
****************************************************************************/
struct gpt_guid_s
{
uint8_t b[16];
};
/* For limited backward compatibility, the space of the legacy MBR is still
* reserved in the GPT specification, but it is now used in a way that
* prevents MBR-based disk utilities from misrecognizing and possibly
* overwriting GPT disks. This is referred to as a protective MBR.
*/
begin_packed_struct struct legacy_partition_s
{
uint8_t boot_ind; /* 0x80 - active */
uint8_t head; /* Starting head */
uint8_t sector; /* Starting sector */
uint8_t cyl; /* Starting cylinder */
uint8_t sys_ind; /* What partition type */
uint8_t end_head; /* End head */
uint8_t end_sector; /* End sector */
uint8_t end_cyl; /* End cylinder */
uint32_t start_sect; /* Starting sector counting from 0 */
uint32_t nr_sects; /* Nr of sectors in partition */
} end_packed_struct;
/* The partition table header defines the usable blocks on the disk.
* It also defines the number and size of the partition entries that
* make up the partition table (offsets 80 and 84 in the table).
*/
begin_packed_struct struct gpt_header_s
{
uint64_t signature; /* EFI PART */
uint32_t revision; /* Revision info */
uint32_t header_size; /* Header size in little endian */
uint32_t header_crc32; /* CRC32 of header (offset +0 up to header size) */
uint32_t reserved1; /* Must be zero */
uint64_t my_lba; /* Current LBA (location of this header copy) */
uint64_t alternate_lba; /* Backup LBA (location of the other header copy) */
uint64_t first_usable_lba; /* First usable LBA for partitions primary partition table last LBA + 1 */
uint64_t last_usable_lba; /* Last usable LBA secondary partition table first LBA - 1 */
struct gpt_guid_s disk_guid; /* Disk GUID in mixed endian */
uint64_t partition_entry_lba; /* Starting LBA of array of partition entries (always 2 in primary copy) */
uint32_t num_partition_entries; /* Number of partition entries in array */
uint32_t sizeof_partition_entry; /* Size of a single partition entry */
uint32_t partition_entry_array_crc32; /* CRC32 of partition entries array in little endian */
/* The rest of the logical block is reserved by UEFI and must be zero.
* EFI standard handles this by:
*
* uint8_t reserved2[ BlockSize - 92 ];
*/
} end_packed_struct;
/* After the header, the Partition Entry Array describes partitions,
* using a minimum size of 128 bytes for each entry block.
*/
/* The 64-bit partition table attributes are shared between 48-bit
* common attributes for all partition types, and 16-bit
* type-specific attributes
*/
begin_packed_struct struct gpt_entry_attributes_s
{
uint64_t required_to_function:1;
uint64_t reserved:47;
uint64_t type_guid_specific:16;
} end_packed_struct;
begin_packed_struct struct gpt_entry_s
{
struct gpt_guid_s partition_type_guid; /* Partition type GUID */
struct gpt_guid_s unique_partition_guid; /* Unique partition GUID */
uint64_t starting_lba; /* First LBA */
uint64_t ending_lba; /* Last LBA */
struct gpt_entry_attributes_s attributes; /* Attribute flags */
uint16_t partition_name[GPT_PARTNAME_MAX_SIZE]; /* Partition name */
} end_packed_struct;
begin_packed_struct struct gpt_ptable_s
{
uint8_t mbr[512];
union
{
struct gpt_header_s gpt_header;
uint8_t gpt[512];
} u;
} end_packed_struct;
/****************************************************************************
* Private Data
****************************************************************************/
static const struct gpt_guid_s g_null_guid;
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: gpt_last_lba
*
* Description:
* Return number of last logical block of device, 0 on error.
*
* Input Parameters:
* state - The partition table state
*
* Returned Value:
* Returns last LBA value on success, 0 on error.
* This is stored (by sd and ide-geometry) in
* the part[0] entry for this disk, and is the number of
* physical sectors available on the disk.
*
****************************************************************************/
static inline blkcnt_t gpt_last_lba(FAR struct partition_state_s *state)
{
return (((uint64_t)state->nblocks) * state->blocksize + GPT_BLOCK_SIZE - 1)
/ GPT_BLOCK_SIZE - 1;
}
/****************************************************************************
* Name: gpt_alloc_verify_entries()
*
* Description:
* reads and verifies partition entries from disk
*
* Input Parameters:
* state - the handle of partition state
* gpt - a GPT header ptr.
*
* Returned Value:
* 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 FAR struct gpt_entry_s *
gpt_alloc_verify_entries(FAR struct partition_state_s *state,
FAR struct gpt_header_s *gpt)
{
FAR struct gpt_entry_s *pte;
unsigned long from;
unsigned long size;
unsigned long blk;
uint32_t crc;
int ret;
size = le32toh(gpt->num_partition_entries) *
le32toh(gpt->sizeof_partition_entry);
if (!size)
{
return NULL;
}
blk = (size + (state->blocksize - 1)) / state->blocksize;
pte = fs_heap_zalloc(blk * state->blocksize);
if (!pte)
{
return NULL;
}
from = GPT_LBA_TO_BLOCK(gpt->partition_entry_lba,
state->blocksize);
ret = read_partition_block(state, pte, from, blk);
if (ret < 0)
{
fs_heap_free(pte);
ferr("Read ptr from block failed:%d.\n", ret);
return NULL;
}
/* Check the GUID Partition Table Entry Array CRC */
crc = crc32part((FAR const uint8_t *)pte, size, ~0l) ^ ~0l;
if (crc != le32toh(gpt->partition_entry_array_crc32))
{
ferr("GUID Partitition Entry Array CRC check failed.\n");
fs_heap_free(pte);
return NULL;
}
return pte;
}
/****************************************************************************
* Name: gpt_header_is_valid
*
* Description:
* tests one GPT header for validity
*
* Input Parameters:
* state - The partition table state
* gpt - is a GPT header ptr.
* lba - is the logical block address of the GPT header to test
*
* Returned Value:
* Returns 0 if valid, a negative errno returned on error.
*
****************************************************************************/
static int gpt_header_is_valid(FAR struct partition_state_s *state,
FAR struct gpt_header_s *gpt, blkcnt_t lba)
{
uint32_t crc;
uint32_t origcrc;
blkcnt_t lastlba;
/* Check the GPT header signature */
if (le64toh(gpt->signature) != GPT_HEADER_SIGNATURE)
{
ferr("GUID Partition Table Header signature is wrong:"
"0x%" PRIx64 " != 0x%llx\n",
le64toh(gpt->signature), GPT_HEADER_SIGNATURE);
return -EINVAL;
}
/* Check the GUID Partition Table CRC */
origcrc = gpt->header_crc32;
gpt->header_crc32 = 0;
crc = crc32part((FAR const uint8_t *)gpt,
le32toh(gpt->header_size), ~0l) ^ ~0l;
if (crc != le32toh(origcrc))
{
ferr("GUID Partition Table Header CRC is wrong: %" PRIx32
" != %" PRIx32 "\n", crc, le32toh(origcrc));
return -EINVAL;
}
gpt->header_crc32 = origcrc;
/* Check that the my_lba entry points to the LBA that contains
* the GUID Partition Table
*/
if (le64toh(gpt->my_lba) != lba)
{
ferr("GPT: my_lba incorrect: %" PRIx64 " != %" PRIxOFF "\n",
le64toh(gpt->my_lba), lba);
return -EINVAL;
}
/* Check the first_usable_lba and last_usable_lba are within the disk. */
lastlba = gpt_last_lba(state);
if (le64toh(gpt->first_usable_lba) > lastlba)
{
ferr("GPT: first_usable_lba incorrect: %" PRId64 " > %" PRIdOFF "\n",
le64toh(gpt->first_usable_lba), lastlba);
return -EINVAL;
}
if (le64toh(gpt->last_usable_lba) > lastlba)
{
ferr("GPT: last_usable_lba incorrect: %" PRId64 " > %" PRIdOFF "\n",
le64toh(gpt->last_usable_lba), lastlba);
return -EINVAL;
}
return OK;
}
/****************************************************************************
* Name: gpt_pte_is_valid()
*
* Description:
* tests one PTE for validity
*
* Input Parameters:
* pte is the pte to check
* lastlba is last lba of the disk
*
* Returned Value:
* Returns 1 if valid, 0 on error.
*
****************************************************************************/
static inline int gpt_pte_is_valid(FAR const struct gpt_entry_s *pte,
blkcnt_t lastlba)
{
if (!memcmp(&pte->partition_type_guid, &g_null_guid,
sizeof(g_null_guid)) ||
le64toh(pte->starting_lba) > lastlba ||
le64toh(pte->ending_lba) > lastlba)
{
return 0;
}
return 1;
}
static void gpt_part_set_name(FAR struct gpt_entry_s *pte,
FAR char *dest, size_t len)
{
int i;
if (--len > GPT_PARTNAME_MAX_SIZE)
{
len = GPT_PARTNAME_MAX_SIZE;
}
for (i = 0; i < len; i++)
{
uint8_t c = pte->partition_name[i];
dest[i] = (c && !isprint(c)) ? '.' : c;
}
dest[i] = 0;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: parse_gpt_partition
*
* Description:
* parse the gpt(EFI GUID Partition Table) partition.
*
* Input Parameters:
* state - The partition table state
* handler - The function to be called for each found partition
* arg - A caller provided value to return with the handler
*
* Returned Value:
* Zero on success; A negated errno value is returned on a failure
*
****************************************************************************/
int parse_gpt_partition(FAR struct partition_state_s *state,
partition_handler_t handler,
FAR void *arg)
{
FAR struct legacy_partition_s *pmbr;
FAR struct gpt_ptable_s *ptbl;
FAR struct gpt_header_s *gpt;
FAR struct gpt_entry_s *ptes;
struct partition_s pentry;
blkcnt_t lastlba;
int nb_part;
int count;
int ret;
/* Read GPT Ptable (LBA0 + LBA1) */
count = (sizeof(struct gpt_ptable_s) + (state->blocksize - 1)) /
state->blocksize;
ptbl = fs_heap_malloc(count * state->blocksize);
if (!ptbl)
{
return -ENOMEM;
}
ret = read_partition_block(state, ptbl, 0, count);
if (ret < 0)
{
goto err;
}
/* Verify mbr is valid */
pmbr = (FAR struct legacy_partition_s *)&ptbl->mbr[0x1be];
if (pmbr->sys_ind != 0xee)
{
ret = -EINVAL;
goto err;
}
/* Verify gpt header is valid */
gpt = &(ptbl->u.gpt_header);
ret = gpt_header_is_valid(state, gpt, 1);
if (ret >= 0)
{
/* Verify gpt header is valid */
ptes = gpt_alloc_verify_entries(state, gpt);
}
if (ret < 0 || !ptes)
{
/* Read and Verify backup gpt header is valid */
finfo("Primary GPT is invalid, using alternate GPT.\n");
count = (GPT_BLOCK_SIZE + state->blocksize - 1) / state->blocksize;
ret = read_partition_block(state, ptbl,
GPT_LBA_TO_BLOCK(gpt->alternate_lba,
state->blocksize), count);
if (ret < 0)
{
goto err;
}
gpt = (FAR struct gpt_header_s *)ptbl;
ret = gpt_header_is_valid(state, gpt,
le64toh(gpt->alternate_lba));
if (ret >= 0)
{
/* Verify gpt header is valid */
ptes = gpt_alloc_verify_entries(state, gpt);
}
}
if (ret < 0 || !ptes)
{
finfo("Alternate GPT is also invalid!!\n");
goto err;
}
lastlba = gpt_last_lba(state);
nb_part = le32toh(gpt->num_partition_entries);
for (pentry.index = 0; pentry.index < nb_part; pentry.index++)
{
/* Skip the empty or invalid entries */
if (!gpt_pte_is_valid(&ptes[pentry.index], lastlba))
{
continue;
}
pentry.firstblock = GPT_LBA_TO_BLOCK(ptes[pentry.index].starting_lba,
state->blocksize);
pentry.nblocks = GPT_LBA_TO_BLOCK(ptes[pentry.index].ending_lba + 1,
state->blocksize) -
pentry.firstblock;
pentry.blocksize = state->blocksize;
gpt_part_set_name(&ptes[pentry.index], pentry.name,
sizeof(pentry.name));
handler(&pentry, arg);
}
fs_heap_free(ptes);
err:
fs_heap_free(ptbl);
return ret;
}
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