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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 */
/** */
/** File */
/** */
/**************************************************************************/
/**************************************************************************/
#define FX_SOURCE_CODE
/* Include necessary system files. */
#include "fx_api.h"
#include "fx_system.h"
#include "fx_directory.h"
#include "fx_file.h"
#include "fx_utility.h"
#ifdef FX_ENABLE_FAULT_TOLERANT
#include "fx_fault_tolerant.h"
#endif /* FX_ENABLE_FAULT_TOLERANT */
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _fx_file_extended_truncate PORTABLE C */
/* 6.1 */
/* AUTHOR */
/* */
/* William E. Lamie, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function sets the file to the specified size, if smaller than */
/* the current file size. If the new file size is less than the */
/* current file read/write position, the internal file pointers will */
/* also be modified. */
/* */
/* INPUT */
/* */
/* file_ptr File control block pointer */
/* size New size of the file in bytes */
/* */
/* OUTPUT */
/* */
/* return status */
/* */
/* CALLS */
/* */
/* _fx_utility_FAT_entry_read Read a FAT entry */
/* _fx_fault_tolerant_transaction_start Start fault tolerant */
/* transaction */
/* _fx_fault_tolerant_transaction_end End fault tolerant transaction*/
/* _fx_fault_tolerant_recover Recover FAT chain */
/* _fx_fault_tolerant_reset_log_file Reset the log file */
/* */
/* CALLED BY */
/* */
/* Application Code */
/* */
/* 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_file_extended_truncate(FX_FILE *file_ptr, ULONG64 size)
{
UINT status;
ULONG cluster;
ULONG contents = 0;
ULONG bytes_per_cluster;
ULONG last_cluster;
ULONG cluster_count;
ULONG64 bytes_remaining;
FX_MEDIA *media_ptr;
#ifndef FX_DONT_UPDATE_OPEN_FILES
ULONG open_count;
FX_FILE *search_ptr;
#endif
#ifdef TX_ENABLE_EVENT_TRACE
TX_TRACE_BUFFER_ENTRY *trace_event;
ULONG trace_timestamp;
#endif
/* First, determine if the file is still open. */
if (file_ptr -> fx_file_id != FX_FILE_ID)
{
/* Return the file not open error status. */
return(FX_NOT_OPEN);
}
#ifndef FX_MEDIA_STATISTICS_DISABLE
/* Setup pointer to media structure. */
media_ptr = file_ptr -> fx_file_media_ptr;
/* Increment the number of times this service has been called. */
media_ptr -> fx_media_file_truncates++;
#endif
/* Setup pointer to associated media control block. */
media_ptr = file_ptr -> fx_file_media_ptr;
/* If trace is enabled, insert this event into the trace buffer. */
FX_TRACE_IN_LINE_INSERT(FX_TRACE_FILE_TRUNCATE, file_ptr, size, file_ptr -> fx_file_current_file_size, 0, FX_TRACE_FILE_EVENTS, &trace_event, &trace_timestamp)
/* Protect against other threads accessing the media. */
FX_PROTECT
/* Make sure this file is open for writing. */
if (file_ptr -> fx_file_open_mode != FX_OPEN_FOR_WRITE)
{
/* Release media protection. */
FX_UNPROTECT
/* Return the access error exception - a write was attempted from
a file opened for reading! */
return(FX_ACCESS_ERROR);
}
/* Check for write protect at the media level (set by driver). */
if (media_ptr -> fx_media_driver_write_protect)
{
/* Release media protection. */
FX_UNPROTECT
/* Return write protect error. */
return(FX_WRITE_PROTECT);
}
/* Setup the new file size - if less than the current size. */
if (size < file_ptr -> fx_file_current_file_size)
{
/* Setup the new size. */
file_ptr -> fx_file_current_file_size = size;
/* Set the modified flag as well. */
file_ptr -> fx_file_modified = FX_TRUE;
/* Update the trace event with the truncated size. */
FX_TRACE_EVENT_UPDATE(trace_event, trace_timestamp, FX_TRACE_FILE_TRUNCATE, 0, 0, 0, size)
}
else
{
/* Update the trace event with the truncated size. */
FX_TRACE_EVENT_UPDATE(trace_event, trace_timestamp, FX_TRACE_FILE_TRUNCATE, 0, 0, 0, file_ptr -> fx_file_current_file_size)
/* Release media protection. */
FX_UNPROTECT
/* Just return, the new size is larger than the current size. */
return(FX_SUCCESS);
}
#ifndef FX_DONT_UPDATE_OPEN_FILES
/* Search the opened files list to see if the same file is opened for reading. */
open_count = media_ptr -> fx_media_opened_file_count;
search_ptr = media_ptr -> fx_media_opened_file_list;
while (open_count)
{
/* Is this file the same file opened for reading? */
if ((search_ptr != file_ptr) &&
(search_ptr -> fx_file_dir_entry.fx_dir_entry_log_sector ==
file_ptr -> fx_file_dir_entry.fx_dir_entry_log_sector) &&
(search_ptr -> fx_file_dir_entry.fx_dir_entry_byte_offset ==
file_ptr -> fx_file_dir_entry.fx_dir_entry_byte_offset))
{
/* Yes, the same file is opened for reading. */
/* Setup the new file size. */
search_ptr -> fx_file_current_file_size = size;
search_ptr -> fx_file_dir_entry.fx_dir_entry_file_size = size;
}
/* Adjust the pointer and decrement the search count. */
search_ptr = search_ptr -> fx_file_opened_next;
open_count--;
}
#endif
/* Now check to see if the read/write internal file pointers need
to be adjusted. */
if (file_ptr -> fx_file_current_file_offset > file_ptr -> fx_file_current_file_size)
{
/* Calculate the number of bytes per cluster. */
bytes_per_cluster = ((ULONG)media_ptr -> fx_media_bytes_per_sector) *
((ULONG)media_ptr -> fx_media_sectors_per_cluster);
/* At this point, we are ready to walk list of clusters to setup the
seek position of this file. */
cluster = file_ptr -> fx_file_first_physical_cluster;
bytes_remaining = size;
last_cluster = 0;
cluster_count = 0;
/* Follow the link of FAT entries. */
while ((cluster >= FX_FAT_ENTRY_START) && (cluster < media_ptr -> fx_media_fat_reserved))
{
/* Increment the number of clusters. */
cluster_count++;
#ifdef FX_ENABLE_EXFAT
if (file_ptr -> fx_file_dir_entry.fx_dir_entry_dont_use_fat & 1)
{
if (cluster >= file_ptr -> fx_file_last_physical_cluster)
{
contents = FX_LAST_CLUSTER_exFAT;
}
else
{
contents = cluster + 1;
}
}
else
{
#endif /* FX_ENABLE_EXFAT */
/* Read the current cluster entry from the FAT. */
status = _fx_utility_FAT_entry_read(media_ptr, cluster, &contents);
/* Check the return value. */
if (status != FX_SUCCESS)
{
/* Release media protection. */
FX_UNPROTECT
/* Return the error status. */
return(status);
}
#ifdef FX_ENABLE_EXFAT
}
#endif /* FX_ENABLE_EXFAT */
/* Save the last valid cluster. */
last_cluster = cluster;
/* Setup for the next cluster. */
cluster = contents;
/* Determine if this is the last written cluster. */
if (bytes_remaining >= bytes_per_cluster)
{
/* Still more seeking, just decrement the working byte offset. */
bytes_remaining = bytes_remaining - bytes_per_cluster;
}
else
{
/* This is the cluster that contains the seek position. */
break;
}
}
/* Check for errors in traversal of the FAT chain. */
if (size > (((ULONG64) bytes_per_cluster) * ((ULONG64) cluster_count)))
{
/* Release media protection. */
FX_UNPROTECT
/* This is an error that suggests a corrupt file. */
return(FX_FILE_CORRUPT);
}
/* Position the pointers to the new offset. */
file_ptr -> fx_file_current_physical_cluster = last_cluster;
file_ptr -> fx_file_current_relative_cluster = cluster_count - 1;
file_ptr -> fx_file_current_logical_sector = ((ULONG)media_ptr -> fx_media_data_sector_start) +
(((ULONG64)file_ptr -> fx_file_current_physical_cluster - FX_FAT_ENTRY_START) *
((ULONG)media_ptr -> fx_media_sectors_per_cluster)) +
(bytes_remaining / (ULONG)media_ptr -> fx_media_bytes_per_sector);
file_ptr -> fx_file_current_relative_sector = (UINT)((bytes_remaining / (ULONG)media_ptr -> fx_media_bytes_per_sector));
file_ptr -> fx_file_current_file_offset = size;
file_ptr -> fx_file_current_logical_offset = (ULONG)bytes_remaining % ((ULONG)media_ptr -> fx_media_bytes_per_sector);
}
#ifdef FX_ENABLE_FAULT_TOLERANT
if (media_ptr -> fx_media_fault_tolerant_enabled)
{
/* Start transaction. */
_fx_fault_tolerant_transaction_start(media_ptr);
/* Copy the new file size into the directory entry. */
file_ptr -> fx_file_dir_entry.fx_dir_entry_file_size = file_ptr -> fx_file_current_file_size;
/* Write the directory entry to the media. */
#ifdef FX_ENABLE_EXFAT
if (media_ptr -> fx_media_FAT_type == FX_exFAT)
{
status = _fx_directory_exFAT_entry_write(media_ptr, &(file_ptr -> fx_file_dir_entry), UPDATE_STREAM);
}
else
{
#endif /* FX_ENABLE_EXFAT */
status = _fx_directory_entry_write(media_ptr, &(file_ptr -> fx_file_dir_entry));
#ifdef FX_ENABLE_EXFAT
}
#endif /* FX_ENABLE_EXFAT */
/* Check for a good status. */
if (status != FX_SUCCESS)
{
FX_FAULT_TOLERANT_TRANSACTION_FAIL(media_ptr);
/* Release media protection. */
FX_UNPROTECT
/* Error writing the directory. */
return(status);
}
/* End transaction. */
status = _fx_fault_tolerant_transaction_end(media_ptr);
/* Check for a good status. */
if (status != FX_SUCCESS)
{
/* Release media protection. */
FX_UNPROTECT
/* Error writing the directory. */
return(status);
}
/* Update maximum size used if necessary. */
if (size < file_ptr -> fx_file_maximum_size_used)
{
file_ptr -> fx_file_maximum_size_used = size;
}
}
#endif /* FX_ENABLE_FAULT_TOLERANT */
/* Release media protection. */
FX_UNPROTECT
/* Truncate is complete, return successful status. */
return(FX_SUCCESS);
}