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/**************************************************************************/
/* */
/* Copyright (c) Microsoft Corporation. All rights reserved. */
/* */
/* This software is licensed under the Microsoft Software License */
/* Terms for Microsoft Azure RTOS. Full text of the license can be */
/* found in the LICENSE file at https://aka.ms/AzureRTOS_EULA */
/* and in the root directory of this software. */
/* */
/**************************************************************************/
/**************************************************************************/
/**************************************************************************/
/** */
/** FileX Component */
/** */
/** Application Utility */
/** */
/**************************************************************************/
/**************************************************************************/
#define FX_SOURCE_CODE
/* Include necessary system files. */
#include "fx_api.h"
#include "fx_utility.h"
/* Define internal data structures. */
typedef struct FX_MEDIA_PARTITION_STRUCT
{
ULONG fx_media_part_start;
ULONG fx_media_part_size;
} FX_MEDIA_PARTITION;
/* Define function prototypes for the partition table parsing application
utility. */
UINT _fx_partition_offset_calculate(void *partition_sector, UINT partition,
ULONG *partition_start, ULONG *partition_size);
UINT _fx_utility_partition_get(FX_MEDIA_PARTITION *partition_table,
UINT *count, ULONG sector, UCHAR *sector_buffer);
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _fx_partition_offset_calculate PORTABLE C */
/* 6.1.6 */
/* AUTHOR */
/* */
/* William E. Lamie, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function calculates the sector offset to the specified */
/* partition. The buffer containing the partition table is also */
/* supplied to this function. If the buffer supplied is a boot */
/* record (which could be the case in non-partition systems), this */
/* function returns an offset of zero, the total sectors, and a */
/* successful status indicating that the buffer supplied is the boot */
/* record. Otherwise, if a partition is found, this function returns */
/* the sector offset to its boot record along with a successful */
/* status. If the specified partition is not found or the buffer is */
/* not a partition table or boot record, this function returns an */
/* error. */
/* */
/* Note: Empty partitions have a FX_SUCCESS return code, however their */
/* starting sector is FX_NULL and the size returned is 0. */
/* */
/* INPUT */
/* */
/* partition_sector Pointer to buffer containing */
/* either the partition table */
/* or the boot sector */
/* partition Desired partition */
/* partition_start Return partition start */
/* partition_size Return partition size */
/* */
/* OUTPUT */
/* */
/* return status */
/* */
/* CALLS */
/* */
/* _fx_utility_partition_get Actual partition parsing */
/* routine */
/* */
/* CALLED BY */
/* */
/* Application Driver */
/* */
/* RELEASE HISTORY */
/* */
/* DATE NAME DESCRIPTION */
/* */
/* 05-19-2020 William E. Lamie Initial Version 6.0 */
/* 09-30-2020 William E. Lamie Modified comment(s), */
/* resulting in version 6.1 */
/* 04-02-2021 William E. Lamie Modified comment(s), */
/* ignored signature check for */
/* no partition situation, */
/* resulting in version 6.1.6 */
/* */
/**************************************************************************/
UINT _fx_partition_offset_calculate(void *partition_sector, UINT partition,
ULONG *partition_start, ULONG *partition_size)
{
FX_MEDIA_PARTITION partition_table[4];
UINT count;
ULONG64 total_sectors;
UCHAR *partition_sector_ptr;
/* Setup working pointer and initialize count. */
partition_sector_ptr = partition_sector;
count = 0;
/* Check for a real boot sector instead of a partition table. */
if ((partition_sector_ptr[0] == 0xe9) || ((partition_sector_ptr[0] == 0xeb) && (partition_sector_ptr[2] == 0x90)))
{
/* Yes, a real boot sector could be present. */
/* See if there are good values for sectors per FAT. */
if (partition_sector_ptr[0x16] || partition_sector_ptr[0x17] || partition_sector_ptr[0x24] || partition_sector_ptr[0x25] || partition_sector_ptr[0x26] || partition_sector_ptr[0x27])
{
/* There are values for sectors per FAT. */
/* Determine if there is a total sector count. */
total_sectors = 0;
if (partition_sector_ptr[0x13] || partition_sector_ptr[0x14])
{
/* Calculate the total sectors, FAT12/16. */
total_sectors = (((ULONG) partition_sector_ptr[0x14]) << 8) | ((ULONG) partition_sector_ptr[0x13]);
}
else if (partition_sector_ptr[0x20] || partition_sector_ptr[0x21] || partition_sector_ptr[0x22] || partition_sector_ptr[0x23])
{
/* Calculate the total sectors, FAT32. */
total_sectors = (((ULONG) partition_sector_ptr[0x23]) << 24) |
(((ULONG) partition_sector_ptr[0x22]) << 16) |
(((ULONG) partition_sector_ptr[0x21]) << 8) |
((ULONG) partition_sector_ptr[0x20]);
}
/* Determine if there is a total sector count. */
if (total_sectors)
{
if (partition_start != FX_NULL)
{
/* Return an offset of 0, size of boot record, and a successful status. */
*partition_start = 0;
}
/* Determine if the total sectors is required. */
if (partition_size != FX_NULL)
{
/* Return the total sectors. */
*partition_size = (ULONG)(total_sectors & 0xFFFFFFFF);
}
/* Return success! */
return(FX_SUCCESS);
}
}
#ifdef FX_ENABLE_EXFAT
/* See if there are good values for sectors per exFAT. */
else if (partition_sector_ptr[0x0b] == 0 && partition_sector_ptr[0x0c] == 0)
{
/* There are values for sectors per exFAT. */
/* Calculate the total sectors. */
total_sectors = _fx_utility_64_unsigned_read(&partition_sector_ptr[FX_EF_VOLUME_LENGTH]);
/* Determine if there is a total sector count. */
if (total_sectors)
{
if (partition_start != FX_NULL)
{
/* Return an offset of 0, size of boot record, and a successful status. */
*partition_start = 0;
}
/* Determine if the total sectors is required. */
if (partition_size != FX_NULL)
{
if (total_sectors > 0xFFFFFFFF)
{
/* Overflow. Just return not found. */
return(FX_NOT_FOUND);
}
/* Return the total sectors. */
*partition_size = (ULONG)(total_sectors & 0xFFFFFFFF);
}
/* Return success! */
return(FX_SUCCESS);
}
}
#endif /* FX_ENABLE_EXFAT */
}
/* Check signature to make sure the buffer is valid. */
if ((partition_sector_ptr[510] != 0x55) || (partition_sector_ptr[511] != 0xAA))
{
/* Invalid, return an error. */
return(FX_NOT_FOUND);
}
/* Not bootable, look for specific partition. */
_fx_utility_partition_get(partition_table, &count, 0, partition_sector_ptr);
/* Determine if return value is valid. */
if (partition >= count)
{
/* No, return an error. */
return(FX_NOT_FOUND);
}
/* Return the partition starting sector, if non-NULL. */
if (partition_start != FX_NULL)
{
*partition_start = partition_table[partition].fx_media_part_start;
}
/* Return the partition size, if non-NULL. */
if (partition_size != FX_NULL)
{
*partition_size = partition_table[partition].fx_media_part_size;
}
/* Return successful completion. */
return(FX_SUCCESS);
}
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _fx_utility_partition_get PORTABLE C */
/* 6.1.6 */
/* AUTHOR */
/* */
/* William E. Lamie, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function parses the partition sector and completes the */
/* supplied partition entry structure. */
/* */
/* INPUT */
/* */
/* partition_table Pointer to partition table */
/* count Number of partitions found */
/* sector Base sector */
/* sector_buffer Buffer containing partition */
/* table */
/* */
/* OUTPUT */
/* */
/* return status */
/* */
/* CALLS */
/* */
/* None */
/* */
/* CALLED BY */
/* */
/* _fx_partition_offset_calculate Calculate partition offset */
/* */
/* RELEASE HISTORY */
/* */
/* DATE NAME DESCRIPTION */
/* */
/* 05-19-2020 William E. Lamie Initial Version 6.0 */
/* 09-30-2020 William E. Lamie Modified comment(s), */
/* resulting in version 6.1 */
/* 04-02-2021 William E. Lamie Modified comment(s), */
/* resulting in version 6.1.6 */
/* */
/**************************************************************************/
UINT _fx_utility_partition_get(FX_MEDIA_PARTITION *partition_table,
UINT *count, ULONG sector, UCHAR *sector_buffer)
{
UINT i;
ULONG base_sector, value;
/* This parameter has not been supported yet. */
FX_PARAMETER_NOT_USED(sector);
/* Initialize base sector. */
base_sector = 0;
for(i = 446; i <= 494; i+=16)
{
if (sector_buffer[i + 4] == 0) /* no partition entry here */
{
partition_table[*count].fx_media_part_start = 0;
partition_table[*count].fx_media_part_size = 0;
}
else
{
value = (ULONG) sector_buffer[i + 8]; /* little endian start value */
value = (((ULONG) sector_buffer[i + 9]) << 8) | value;
value = (((ULONG) sector_buffer[i + 10]) << 16) | value;
value = (((ULONG) sector_buffer[i + 11]) << 24) | value;
partition_table[*count].fx_media_part_start = value + base_sector;
value = (ULONG) sector_buffer[i + 12]; /* little endian size value */
value = (((ULONG) sector_buffer[i + 13]) << 8) | value;
value = (((ULONG) sector_buffer[i + 14]) << 16) | value;
value = (((ULONG) sector_buffer[i + 15]) << 24) | value;
partition_table[*count].fx_media_part_size = value;
}
(*count)++;
}
/* Return success. */
return(FX_SUCCESS);
}