mirror of
https://github.com/eclipse-threadx/filex.git
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168 lines
7.6 KiB
C
168 lines
7.6 KiB
C
/**************************************************************************/
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/* */
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/* Copyright (c) Microsoft Corporation. All rights reserved. */
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/* */
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/* This software is licensed under the Microsoft Software License */
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/* Terms for Microsoft Azure RTOS. Full text of the license can be */
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/* found in the LICENSE file at https://aka.ms/AzureRTOS_EULA */
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/* and in the root directory of this software. */
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/* */
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/**************************************************************************/
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/**************************************************************************/
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/**************************************************************************/
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/** */
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/** FileX Component */
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/** */
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/** Fault Tolerant */
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/** */
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/**************************************************************************/
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/**************************************************************************/
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#define FX_SOURCE_CODE
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#include "fx_api.h"
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#include "fx_utility.h"
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#include "fx_fault_tolerant.h"
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#ifdef FX_ENABLE_FAULT_TOLERANT
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/**************************************************************************/
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/* */
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/* FUNCTION RELEASE */
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/* */
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/* _fx_fault_tolerant_read_FAT PORTABLE C */
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/* 6.1 */
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/* AUTHOR */
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/* */
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/* William E. Lamie, Microsoft Corporation */
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/* */
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/* DESCRIPTION */
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/* */
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/* This function reads value of a FAT entry from log file if it */
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/* exists. During file or directory operations with Fault Tolerant */
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/* protection, intermediate operations are written to the fault */
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/* tolerant log files. Therefore, FAT-entry read should search for */
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/* fault tolerant log before the request can be passed to normal FAT */
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/* entry read routine. */
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/* */
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/* INPUT */
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/* */
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/* media_ptr Media control block pointer */
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/* cluster Cluster entry number */
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/* value Pointer to value for the entry*/
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/* log_type FAT or bitmap */
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/* */
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/* OUTPUT */
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/* */
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/* return status */
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/* */
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/* CALLS */
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/* */
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/* _fx_utility_16_unsigned_read Read a USHORT from memory */
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/* _fx_utility_32_unsigned_read Read a ULONG from memory */
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/* */
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/* CALLED BY */
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/* */
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/* _fx_utility_FAT_entry_read */
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/* */
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/* RELEASE HISTORY */
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/* */
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/* DATE NAME DESCRIPTION */
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/* */
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/* 05-19-2020 William E. Lamie Initial Version 6.0 */
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/* 09-30-2020 William E. Lamie Modified comment(s), */
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/* resulting in version 6.1 */
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/* */
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/**************************************************************************/
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UINT _fx_fault_tolerant_read_FAT(FX_MEDIA *media_ptr, ULONG cluster, ULONG *value, ULONG log_type)
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{
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ULONG logs_remaining;
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UCHAR *current_ptr;
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UCHAR found = FX_FALSE;
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ULONG size;
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USHORT type;
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ULONG log_len;
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FX_FAULT_TOLERANT_FAT_LOG *fat_log;
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/* Get fault tolerant data. */
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logs_remaining = media_ptr -> fx_media_fault_tolerant_total_logs;
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/* Any redo logs? */
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if (logs_remaining == 0)
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{
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/* No. Just return. */
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return(FX_READ_CONTINUE);
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}
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/* Get size of all logs. */
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size = media_ptr -> fx_media_fault_tolerant_file_size - FX_FAULT_TOLERANT_LOG_CONTENT_OFFSET;
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/* Get the first log pointer. */
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current_ptr = media_ptr -> fx_media_fault_tolerant_memory_buffer +
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FX_FAULT_TOLERANT_LOG_CONTENT_OFFSET +
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FX_FAULT_TOLERANT_LOG_CONTENT_HEADER_SIZE;
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/* Loop throught all FAT logs. */
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while (logs_remaining)
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{
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/* Check log type. */
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type = (USHORT)_fx_utility_16_unsigned_read(current_ptr);
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/* Get log length. */
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log_len = _fx_utility_16_unsigned_read(current_ptr + 2);
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/* Validate the size value. */
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if (log_len > size)
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{
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/* Log file is corrupted. Nothing can be done. Return.*/
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return(FX_FILE_CORRUPT);
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}
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size -= log_len;
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/* Check log type. */
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if (type == log_type)
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{
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/* This is the log with same type . */
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/* Get the log pointer. */
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fat_log = (FX_FAULT_TOLERANT_FAT_LOG *)current_ptr;
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/* Is this FAT log entry the one looking for? */
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if (_fx_utility_32_unsigned_read((UCHAR *)&fat_log -> fx_fault_tolerant_FAT_log_cluster) == cluster)
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{
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/* Yes, it is. */
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*value = _fx_utility_32_unsigned_read((UCHAR *)&fat_log -> fx_fault_tolerant_FAT_log_value);
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/* Do not return since there may be more than one log for this cluster. */
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found = FX_TRUE;
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}
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}
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/* Decrease the logs_remaining counter. */
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logs_remaining--;
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/* Get next log pointer. */
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current_ptr += log_len;
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}
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if (found != FX_TRUE)
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{
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/* Pass the request to FAT entry read. */
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return(FX_READ_CONTINUE);
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}
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/* Return success. */
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return(FX_SUCCESS);
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}
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#endif /* FX_ENABLE_FAULT_TOLERANT */
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