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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 */
/** */
/** Fault Tolerant */
/** */
/**************************************************************************/
/**************************************************************************/
#define FX_SOURCE_CODE
#include "fx_api.h"
#include "fx_utility.h"
#include "fx_fault_tolerant.h"
#ifdef FX_ENABLE_FAULT_TOLERANT
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _fx_fault_tolerant_read_FAT PORTABLE C */
/* 6.1 */
/* AUTHOR */
/* */
/* William E. Lamie, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function reads value of a FAT entry from log file if it */
/* exists. During file or directory operations with Fault Tolerant */
/* protection, intermediate operations are written to the fault */
/* tolerant log files. Therefore, FAT-entry read should search for */
/* fault tolerant log before the request can be passed to normal FAT */
/* entry read routine. */
/* */
/* INPUT */
/* */
/* media_ptr Media control block pointer */
/* cluster Cluster entry number */
/* value Pointer to value for the entry*/
/* log_type FAT or bitmap */
/* */
/* OUTPUT */
/* */
/* return status */
/* */
/* CALLS */
/* */
/* _fx_utility_16_unsigned_read Read a USHORT from memory */
/* _fx_utility_32_unsigned_read Read a ULONG from memory */
/* */
/* CALLED BY */
/* */
/* _fx_utility_exFAT_cluster_state_get */
/* _fx_utility_FAT_entry_read */
/* */
/* 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 */
/* */
/**************************************************************************/
UINT _fx_fault_tolerant_read_FAT(FX_MEDIA *media_ptr, ULONG cluster, ULONG *value, ULONG log_type)
{
ULONG logs_remaining;
UCHAR *current_ptr;
UCHAR found = FX_FALSE;
ULONG size;
USHORT type;
ULONG log_len;
FX_FAULT_TOLERANT_FAT_LOG *fat_log;
#ifdef FX_ENABLE_EXFAT
FX_FAULT_TOLERANT_BITMAP_LOG *bitmap_log;
#endif
/* Get fault tolerant data. */
logs_remaining = media_ptr -> fx_media_fault_tolerant_total_logs;
/* Any redo logs? */
if (logs_remaining == 0)
{
/* No. Just return. */
return(FX_READ_CONTINUE);
}
/* Get size of all logs. */
size = media_ptr -> fx_media_fault_tolerant_file_size - FX_FAULT_TOLERANT_LOG_CONTENT_OFFSET;
/* Get the first log pointer. */
current_ptr = media_ptr -> fx_media_fault_tolerant_memory_buffer +
FX_FAULT_TOLERANT_LOG_CONTENT_OFFSET +
FX_FAULT_TOLERANT_LOG_CONTENT_HEADER_SIZE;
/* Loop throught all FAT logs. */
while (logs_remaining)
{
/* Check log type. */
type = (USHORT)_fx_utility_16_unsigned_read(current_ptr);
/* Get log length. */
log_len = _fx_utility_16_unsigned_read(current_ptr + 2);
/* Validate the size value. */
if (log_len > size)
{
/* Log file is corrupted. Nothing can be done. Return.*/
return(FX_FILE_CORRUPT);
}
size -= log_len;
/* Check log type. */
if (type == log_type)
{
/* This is the log with same type . */
/* Get the log pointer. */
#ifdef FX_ENABLE_EXFAT
if (type == FX_FAULT_TOLERANT_BITMAP_LOG_TYPE)
{
bitmap_log = (FX_FAULT_TOLERANT_BITMAP_LOG *)current_ptr;
/* Is this bitmap log entry the one looking for? */
if (_fx_utility_32_unsigned_read((UCHAR *)&bitmap_log -> fx_fault_tolerant_bitmap_log_cluster) == cluster)
{
/* Yes, it is. */
*value = _fx_utility_32_unsigned_read((UCHAR *)&bitmap_log -> fx_fault_tolerant_bitmap_log_value);
/* Do not return since there may be more than one log for this cluster. */
found = FX_TRUE;
}
}
else
{
#endif /* FX_ENABLE_EXFAT */
fat_log = (FX_FAULT_TOLERANT_FAT_LOG *)current_ptr;
/* Is this FAT log entry the one looking for? */
if (_fx_utility_32_unsigned_read((UCHAR *)&fat_log -> fx_fault_tolerant_FAT_log_cluster) == cluster)
{
/* Yes, it is. */
*value = _fx_utility_32_unsigned_read((UCHAR *)&fat_log -> fx_fault_tolerant_FAT_log_value);
/* Do not return since there may be more than one log for this cluster. */
found = FX_TRUE;
}
#ifdef FX_ENABLE_EXFAT
}
#endif /* FX_ENABLE_EXFAT */
}
/* Decrease the logs_remaining counter. */
logs_remaining--;
/* Get next log pointer. */
current_ptr += log_len;
}
if (found != FX_TRUE)
{
/* Pass the request to FAT entry read. */
return(FX_READ_CONTINUE);
}
/* Return success. */
return(FX_SUCCESS);
}
#endif /* FX_ENABLE_FAULT_TOLERANT */
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