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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_release PORTABLE C */
/* 6.1.3 */
/* 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. Any unused clusters are released back to the */
/* media. */
/* */
/* INPUT */
/* */
/* file_ptr File control block pointer */
/* size New size of the file in bytes */
/* */
/* OUTPUT */
/* */
/* return status */
/* */
/* CALLS */
/* */
/* _fx_directory_entry_write Write directory entry */
/* _fx_utility_exFAT_bitmap_flush Flush exFAT allocation bitmap */
/* _fx_utility_exFAT_cluster_state_set Set cluster state */
/* _fx_utility_FAT_entry_read Read a FAT entry */
/* _fx_utility_FAT_entry_write Write a FAT entry */
/* _fx_utility_FAT_flush Flush written FAT entries */
/* _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 */
/* _fx_fault_tolerant_set_FAT_chain Set data of FAT chain */
/* */
/* 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 */
/* 12-31-2020 William E. Lamie Modified comment(s), fixed */
/* available cluster issue, */
/* resulting in version 6.1.3 */
/* */
/**************************************************************************/
UINT _fx_file_extended_truncate_release(FX_FILE *file_ptr, ULONG64 size)
{
UINT status;
ULONG cluster;
ULONG contents;
ULONG bytes_per_cluster;
ULONG last_cluster;
ULONG cluster_count;
ULONG64 bytes_remaining;
FX_MEDIA *media_ptr;
#ifdef FX_ENABLE_EXFAT
ULONG original_last_physical_cluster;
#endif /* FX_ENABLE_EXFAT */
#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_truncate_releases++;
#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_RELEASE, 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
#ifdef FX_ENABLE_FAULT_TOLERANT
/* Start transaction. */
_fx_fault_tolerant_transaction_start(media_ptr);
#endif /* FX_ENABLE_FAULT_TOLERANT */
/* Make sure this file is open for writing. */
if (file_ptr -> fx_file_open_mode != FX_OPEN_FOR_WRITE)
{
#ifdef FX_ENABLE_FAULT_TOLERANT
FX_FAULT_TOLERANT_TRANSACTION_FAIL(media_ptr);
#endif /* FX_ENABLE_FAULT_TOLERANT */
/* 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)
{
#ifdef FX_ENABLE_FAULT_TOLERANT
FX_FAULT_TOLERANT_TRANSACTION_FAIL(media_ptr);
#endif /* FX_ENABLE_FAULT_TOLERANT */
/* Release media protection. */
FX_UNPROTECT
/* Return write protect error. */
return(FX_WRITE_PROTECT);
}
/* 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);
/* Check for invalid value. */
if (bytes_per_cluster == 0)
{
#ifdef FX_ENABLE_FAULT_TOLERANT
FX_FAULT_TOLERANT_TRANSACTION_FAIL(media_ptr);
#endif /* FX_ENABLE_FAULT_TOLERANT */
/* Release media protection. */
FX_UNPROTECT
/* Invalid media, return error. */
return(FX_MEDIA_INVALID);
}
/* Setup the new file available size - if less than the current available size. */
if (size < file_ptr -> fx_file_current_available_size)
{
/* Yes, the file needs to be truncated. */
/* Update the available file size. */
file_ptr -> fx_file_current_available_size = ((size + bytes_per_cluster - 1) / bytes_per_cluster) * bytes_per_cluster;
/* Is the new available size less than the actual file size? */
if (size < file_ptr -> fx_file_current_file_size)
{
/* Setup the new file size. */
file_ptr -> fx_file_current_file_size = size;
/* Set the modified flag. */
file_ptr -> fx_file_modified = FX_TRUE;
/* Copy the new file size into the directory entry. */
file_ptr -> fx_file_dir_entry.fx_dir_entry_file_size = size;
/* Set the first cluster to NULL. */
if (size == 0)
{
/* Yes, the first cluster needs to be cleared since the entire
file is going to be truncated. */
file_ptr -> fx_file_dir_entry.fx_dir_entry_cluster = FX_NULL;
}
/* 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)
{
#ifdef FX_ENABLE_FAULT_TOLERANT
FX_FAULT_TOLERANT_TRANSACTION_FAIL(media_ptr);
#endif /* FX_ENABLE_FAULT_TOLERANT */
/* Release media protection. */
FX_UNPROTECT
/* Error writing the directory. */
return(status);
}
}
/* Update the trace event with the truncated size. */
FX_TRACE_EVENT_UPDATE(trace_event, trace_timestamp, FX_TRACE_FILE_TRUNCATE_RELEASE, 0, 0, 0, file_ptr -> fx_file_current_file_size)
}
else
{
/* Update the trace event with the truncated size. */
FX_TRACE_EVENT_UPDATE(trace_event, trace_timestamp, FX_TRACE_FILE_TRUNCATE_RELEASE, 0, 0, 0, file_ptr -> fx_file_current_file_size)
#ifdef FX_ENABLE_FAULT_TOLERANT
FX_FAULT_TOLERANT_TRANSACTION_FAIL(media_ptr);
#endif /* FX_ENABLE_FAULT_TOLERANT */
/* Release media protection. */
FX_UNPROTECT
/* Just return, the truncate size is larger than the available size. */
return(FX_SUCCESS);
}
/* 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);
/* 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)
{
/* 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)
{
#ifdef FX_ENABLE_FAULT_TOLERANT
FX_FAULT_TOLERANT_TRANSACTION_FAIL(media_ptr);
#endif /* FX_ENABLE_FAULT_TOLERANT */
/* 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)))
{
#ifdef FX_ENABLE_FAULT_TOLERANT
FX_FAULT_TOLERANT_TRANSACTION_FAIL(media_ptr);
#endif /* FX_ENABLE_FAULT_TOLERANT */
/* 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);
}
/* Determine how many clusters are actually in-use now. */
cluster_count = (ULONG) (file_ptr -> fx_file_current_available_size + (((ULONG64) bytes_per_cluster) - ((ULONG64) 1)))/bytes_per_cluster;
/* Save the number of clusters in-use. */
file_ptr -> fx_file_total_clusters = cluster_count;
/* At this point, we are ready to walk list of clusters to find the clusters
that can be released. */
cluster = file_ptr -> fx_file_first_physical_cluster;
#ifdef FX_ENABLE_EXFAT
original_last_physical_cluster = file_ptr -> fx_file_last_physical_cluster;
#endif /* FX_ENABLE_EXFAT */
#ifdef FX_ENABLE_FAULT_TOLERANT
/* Is this the last used cluster? */
if ((cluster_count == 0) && (media_ptr -> fx_media_fault_tolerant_enabled))
{
#ifdef FX_ENABLE_EXFAT
if (!(file_ptr -> fx_file_dir_entry.fx_dir_entry_dont_use_fat & 1))
{
#endif /* FX_ENABLE_EXFAT */
/* Set undo log. */
status = _fx_fault_tolerant_set_FAT_chain(media_ptr, FX_FALSE, FX_FREE_CLUSTER,
media_ptr -> fx_media_fat_last, cluster, media_ptr -> fx_media_fat_last);
/* Determine if the write was successful. */
if (status != FX_SUCCESS)
{
FX_FAULT_TOLERANT_TRANSACTION_FAIL(media_ptr);
/* Release media protection. */
FX_UNPROTECT
/* Return the error code. */
return(status);
}
#ifdef FX_ENABLE_EXFAT
}
else
{
/* Set undo log. */
status = _fx_fault_tolerant_set_FAT_chain(media_ptr, FX_TRUE, FX_FREE_CLUSTER,
media_ptr -> fx_media_fat_last, cluster, file_ptr -> fx_file_last_physical_cluster + 1);
/* Determine if the write was successful. */
if (status != FX_SUCCESS)
{
FX_FAULT_TOLERANT_TRANSACTION_FAIL(media_ptr);
/* Release media protection. */
FX_UNPROTECT
/* Return the error code. */
return(status);
}
}
#endif /* FX_ENABLE_EXFAT && FX_ENABLE_FAULT_TOLERANT */
file_ptr -> fx_file_last_physical_cluster = cluster;
}
#endif /* FX_ENABLE_FAULT_TOLERANT */
/* Follow the link of FAT entries. */
while ((cluster >= FX_FAT_ENTRY_START) && (cluster < media_ptr -> fx_media_fat_reserved))
{
#ifdef FX_ENABLE_EXFAT
if (file_ptr -> fx_file_dir_entry.fx_dir_entry_dont_use_fat & 1)
{
if (cluster >= original_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)
{
#ifdef FX_ENABLE_FAULT_TOLERANT
FX_FAULT_TOLERANT_TRANSACTION_FAIL(media_ptr);
#endif /* FX_ENABLE_FAULT_TOLERANT */
/* Release media protection. */
FX_UNPROTECT
/* Return the error status. */
return(status);
}
#ifdef FX_ENABLE_EXFAT
}
#endif /* FX_ENABLE_EXFAT */
/* Determine if are more clusters to release. */
if (cluster_count > 0)
{
/* Decrement the number of clusters. */
cluster_count--;
/* Is this the last used cluster? */
if (cluster_count == 0)
{
#ifdef FX_ENABLE_EXFAT
if (!(file_ptr -> fx_file_dir_entry.fx_dir_entry_dont_use_fat & 1))
#endif /* FX_ENABLE_EXFAT */
{
#ifdef FX_ENABLE_FAULT_TOLERANT
if (media_ptr -> fx_media_fault_tolerant_enabled)
{
/* Set undo phase. */
media_ptr -> fx_media_fault_tolerant_state |= FX_FAULT_TOLERANT_STATE_SET_FAT_CHAIN;
/* 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)
{
FX_FAULT_TOLERANT_TRANSACTION_FAIL(media_ptr);
/* Release media protection. */
FX_UNPROTECT
/* Return the error status. */
return(status);
}
/* Set undo log. */
status = _fx_fault_tolerant_set_FAT_chain(media_ptr, FX_FALSE, cluster,
media_ptr -> fx_media_fat_last, contents, media_ptr -> fx_media_fat_last);
/* Determine if the write was successful. */
if (status != FX_SUCCESS)
{
FX_FAULT_TOLERANT_TRANSACTION_FAIL(media_ptr);
/* Release media protection. */
FX_UNPROTECT
/* Return the error code. */
return(status);
}
}
#endif /* FX_ENABLE_FAULT_TOLERANT */
/* Yes, it should be designated as last cluster. */
status = _fx_utility_FAT_entry_write(media_ptr, cluster, media_ptr -> fx_media_fat_last);
/* Check the return value. */
if (status)
{
#ifdef FX_ENABLE_FAULT_TOLERANT
FX_FAULT_TOLERANT_TRANSACTION_FAIL(media_ptr);
#endif /* FX_ENABLE_FAULT_TOLERANT */
/* Release media protection. */
FX_UNPROTECT
/* Return the error status. */
return(status);
}
#ifdef FX_ENABLE_FAULT_TOLERANT
if (media_ptr -> fx_media_fault_tolerant_enabled)
{
/* Clear undo phase. */
media_ptr -> fx_media_fault_tolerant_state &= (UCHAR)(~FX_FAULT_TOLERANT_STATE_SET_FAT_CHAIN & 0xff);
}
#endif /* FX_ENABLE_FAULT_TOLERANT */
}
#if defined(FX_ENABLE_EXFAT) && defined(FX_ENABLE_FAULT_TOLERANT)
else if (media_ptr -> fx_media_fault_tolerant_enabled)
{
/* Set undo log. */
status = _fx_fault_tolerant_set_FAT_chain(media_ptr, FX_TRUE, cluster,
media_ptr -> fx_media_fat_last, contents, file_ptr -> fx_file_last_physical_cluster + 1);
/* Determine if the write was successful. */
if (status != FX_SUCCESS)
{
FX_FAULT_TOLERANT_TRANSACTION_FAIL(media_ptr);
/* Release media protection. */
FX_UNPROTECT
/* Return the error code. */
return(status);
}
}
#endif /* FX_ENABLE_EXFAT && FX_ENABLE_FAULT_TOLERANT */
file_ptr -> fx_file_last_physical_cluster = cluster;
#ifdef FX_FAULT_TOLERANT
/* Flush the cached individual FAT entries. */
status = _fx_utility_FAT_flush(media_ptr);
/* Check the return value. */
if (status)
{
#ifdef FX_ENABLE_FAULT_TOLERANT
FX_FAULT_TOLERANT_TRANSACTION_FAIL(media_ptr);
#endif /* FX_ENABLE_FAULT_TOLERANT */
/* Release media protection. */
FX_UNPROTECT
/* Return the error status. */
return(status);
}
#endif
}
}
else
{
/* This is a cluster after the clusters used by the file, release
it back to the media. */
#ifdef FX_ENABLE_FAULT_TOLERANT
if (media_ptr -> fx_media_fault_tolerant_enabled == FX_FALSE)
{
#endif /* FX_ENABLE_FAULT_TOLERANT */
#ifdef FX_ENABLE_EXFAT
if (!(file_ptr -> fx_file_dir_entry.fx_dir_entry_dont_use_fat & 1))
{
#endif /* FX_ENABLE_EXFAT */
status = _fx_utility_FAT_entry_write(media_ptr, cluster, FX_FREE_CLUSTER);
/* Check the return value. */
if (status)
{
#ifdef FX_ENABLE_FAULT_TOLERANT
FX_FAULT_TOLERANT_TRANSACTION_FAIL(media_ptr);
#endif /* FX_ENABLE_FAULT_TOLERANT */
/* Release media protection. */
FX_UNPROTECT
/* Return the error status. */
return(status);
}
#ifdef FX_ENABLE_EXFAT
}
if (media_ptr -> fx_media_FAT_type == FX_exFAT)
{
/* Mark the cluster as free. */
_fx_utility_exFAT_cluster_state_set(media_ptr, cluster, FX_EXFAT_BITMAP_CLUSTER_FREE);
}
#endif /* FX_ENABLE_EXFAT */
/* Increment the number of available clusters. */
media_ptr -> fx_media_available_clusters++;
#ifdef FX_ENABLE_FAULT_TOLERANT
}
#endif /* FX_ENABLE_FAULT_TOLERANT */
}
/* Setup for the next cluster. */
cluster = contents;
}
/* Determine if we need to adjust the number of leading consecutive clusters. */
if (file_ptr -> fx_file_consecutive_cluster > file_ptr -> fx_file_total_clusters)
{
/* Adjust the leading consecutive cluster count. */
file_ptr -> fx_file_consecutive_cluster = file_ptr -> fx_file_total_clusters;
}
/* Determine if the file available size has been truncated to zero. */
if (file_ptr -> fx_file_current_available_size == 0)
{
/* Yes, the first cluster has already been released. Update the file info
to indicate the file has no clusters. */
file_ptr -> fx_file_last_physical_cluster = 0;
file_ptr -> fx_file_first_physical_cluster = 0;
file_ptr -> fx_file_current_physical_cluster = 0;
file_ptr -> fx_file_current_logical_sector = 0;
file_ptr -> fx_file_current_relative_cluster = 0;
file_ptr -> fx_file_current_relative_sector = 0;
file_ptr -> fx_file_current_available_size = 0;
file_ptr -> fx_file_consecutive_cluster = 1;
}
#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;
/* Setup the new total clusters. */
search_ptr -> fx_file_total_clusters = file_ptr -> fx_file_total_clusters;
/* Copy the directory entry. */
search_ptr -> fx_file_dir_entry.fx_dir_entry_cluster = file_ptr -> fx_file_dir_entry.fx_dir_entry_cluster;
search_ptr -> fx_file_dir_entry.fx_dir_entry_file_size = file_ptr -> fx_file_dir_entry.fx_dir_entry_file_size;
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;
/* Setup the other file parameters. */
search_ptr -> fx_file_last_physical_cluster = file_ptr -> fx_file_last_physical_cluster;
search_ptr -> fx_file_first_physical_cluster = file_ptr -> fx_file_first_physical_cluster;
search_ptr -> fx_file_current_available_size = file_ptr -> fx_file_current_available_size;
search_ptr -> fx_file_consecutive_cluster = file_ptr -> fx_file_consecutive_cluster;
/* Determine if the truncated file is smaller than the current file offset. */
if (search_ptr -> fx_file_current_file_offset > size)
{
/* Yes, the current file parameters need to be changed since the file was
truncated to a position prior to the current file position. */
/* 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 = search_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)
{
#ifdef FX_ENABLE_FAULT_TOLERANT
FX_FAULT_TOLERANT_TRANSACTION_FAIL(media_ptr);
#endif /* FX_ENABLE_FAULT_TOLERANT */
/* 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)))
{
#ifdef FX_ENABLE_FAULT_TOLERANT
FX_FAULT_TOLERANT_TRANSACTION_FAIL(media_ptr);
#endif /* FX_ENABLE_FAULT_TOLERANT */
/* 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. */
/* Determine if there is at least one cluster. */
if (cluster_count)
{
/* Calculate real file parameters. */
search_ptr -> fx_file_current_physical_cluster = last_cluster;
search_ptr -> fx_file_current_relative_cluster = cluster_count - 1;
search_ptr -> fx_file_current_logical_sector = ((ULONG)media_ptr -> fx_media_data_sector_start) +
(((ULONG64)search_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);
search_ptr -> fx_file_current_relative_sector = (UINT)((bytes_remaining / (ULONG)media_ptr -> fx_media_bytes_per_sector));
search_ptr -> fx_file_current_file_offset = size;
search_ptr -> fx_file_current_logical_offset = (ULONG)bytes_remaining % ((ULONG)media_ptr -> fx_media_bytes_per_sector);
}
else
{
/* Calculate zero-length file parameters. */
search_ptr -> fx_file_current_physical_cluster = 0;
search_ptr -> fx_file_current_relative_cluster = 0;
search_ptr -> fx_file_current_logical_sector = 0;
search_ptr -> fx_file_current_relative_sector = 0;
search_ptr -> fx_file_current_file_offset = 0;
search_ptr -> fx_file_current_logical_offset = 0;
}
}
}
/* Adjust the pointer and decrement the search count. */
search_ptr = search_ptr -> fx_file_opened_next;
open_count--;
}
#endif
#ifdef FX_FAULT_TOLERANT
/* Flush the cached individual FAT entries */
status = _fx_utility_FAT_flush(media_ptr);
/* Check the return value. */
if (status)
{
#ifdef FX_ENABLE_FAULT_TOLERANT
FX_FAULT_TOLERANT_TRANSACTION_FAIL(media_ptr);
#endif /* FX_ENABLE_FAULT_TOLERANT */
/* Release media protection. */
FX_UNPROTECT
/* Return the error status. */
return(status);
}
#ifdef FX_ENABLE_EXFAT
/* Flush Bit Map. */
if (media_ptr -> fx_media_FAT_type == FX_exFAT)
{
_fx_utility_exFAT_bitmap_flush(media_ptr);
}
#endif /* FX_ENABLE_EXFAT */
#endif
#ifdef FX_ENABLE_FAULT_TOLERANT
if (media_ptr -> fx_media_fault_tolerant_enabled &&
(media_ptr -> fx_media_fault_tolerant_state & FX_FAULT_TOLERANT_STATE_STARTED))
{
/* 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 bad status. */
if (status != FX_SUCCESS)
{
/* Release media protection. */
FX_UNPROTECT
/* Return the bad status. */
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);
}