// Copyright (c) 2009 Nokia Corporation and/or its subsidiary(-ies).
// All rights reserved.
// This component and the accompanying materials are made available
// under the terms of "Eclipse Public License v1.0"
// which accompanies this distribution, and is available
// at the URL "http://www.eclipse.org/legal/epl-v10.html".
//
// Initial Contributors:
// Nokia Corporation - initial contribution.
//
// Contributors:
//
// Description:
// Classes that allow the editing and creation of Symbian ELF files
//
/**
* @file selflib.cpp
* @prototype
*/
#include <f32file.h>
#include "selflib.h"
#include "debuglogging.h"
#include "symbianelfstringinfov2.h"
#include "symbianelfstringinfo.h"
/**
* First stage construction
* @return Pointer to new CSELFEditor object
* @leave One of the System Wide Error Codes
*/
EXPORT_C CSELFEditor* CSELFEditor::NewL(const TDesC& aFilename)
{
LOG_ENTRY();
CSELFEditor* self = CSELFEditor::NewLC(aFilename);
CleanupStack::Pop();
return self;
}
/**
* First stage construction. Object is left upon cleanup stack
* @return Pointer to new CSELFEditor object
* @leave One of the System Wide Error Codes
*/
EXPORT_C CSELFEditor* CSELFEditor::NewLC(const TDesC& aFilename)
{
LOG_ENTRY();
CSELFEditor* self = new(ELeave)CSELFEditor();
CleanupStack::PushL(self);
self->ConstructL(aFilename);
return self;
}
/**
* CSELFEditor Desctructor
*/
CSELFEditor::~CSELFEditor()
{
LOG_ENTRY();
delete iRawData;
delete iStringTable;
iELFFile.Close();
iFsSession.Close();
iNewSegments.Close();
iProgramHeaders.Close();
}
/**
* Second stage safe construction
* @leave One of the System Wide Error Codes
*/
void CSELFEditor::ConstructL(const TDesC& aFilename)
{
LOG_ENTRY();
User::LeaveIfError(iFsSession.Connect());
User::LeaveIfError(iELFFile.Open(iFsSession, aFilename, EFileWrite));
TInt fileSize;
User::LeaveIfError(iELFFile.Size(fileSize));
//Check its big enough to at least read the header
if(fileSize < sizeof(Elf32_Ehdr))
{
LOG_MSG("\tCSELFEditor::ConstructL --> File is not big enough to be an ELF file");
User::Leave(KErrCorrupt);
}
CacheELFHeaderL();
//Validate the ELF file
if(!IsValidELFFile())
User::Leave(KErrCorrupt);
if(!IsELFFileSupported())
User::Leave(KErrNotSupported);
iRawData = new(ELeave) CDesC8ArrayFlat(1);
CacheProgramHeadersL();
CacheStringTableL();
}
/**
* Caches ELF File internally in this object
* @see GetELFHeader
* @leave One of the system wide error codes
*/
void CSELFEditor::CacheELFHeaderL()
{
//Read the ELF header
TUint fileLocation = 0;
TPtr8 hdrDes((TUint8*)&iELFHeader, sizeof(Elf32_Ehdr));
User::LeaveIfError(iELFFile.Read(fileLocation, hdrDes));
}
/**
* CSELFEditor Constructor
*/
CSELFEditor::CSELFEditor()
{}
/**
* This ELF library currently only supports a specific subset of the ELF standard.
* This function makes sure the ELF file supplied is part of that subset. These are the things
* we do not currently support:
* 1. 64 Bit ELF
* 2. ELFDATA2MSB File class (Big Endian)
* 3. Any sections
* 4. Any type other than ET_CORE
*
* @return TBool indicating if the file is OK to continue with
*/
TBool CSELFEditor::IsELFFileSupported()
{
LOG_ENTRY();
TBool supported = ETrue;
if(iELFHeader.e_ident[EI_CLASS] != ELFCLASS32)
{
LOG_MSG("\tCSELFEditor::IsElfFileSupported() --> Non 32 bit files are not supported");
supported = EFalse;
}
if(iELFHeader.e_ident[EI_DATA] != ELFDATA2LSB)
{
LOG_MSG("\tCSELFEditor::IsElfFileSupported() --> Only support Little Endian");
supported = EFalse;
}
if(iELFHeader.e_type != ET_CORE)
{
LOG_MSG("\tCSELFEditor::IsElfFileSupported() --> Only support Core Files");
supported = EFalse;
}
if(iELFHeader.e_shoff != 0 || iELFHeader.e_shnum != 0)
{
LOG_MSG("\tCSELFEditor::IsElfFileSupported() --> Do not support Sections");
supported = EFalse;
}
return supported;
}
/**
* Validates the ELF file by looking at the signature
* @return Boolean indicating whether or not the file is valid ELF
*/
TBool CSELFEditor::IsValidELFFile()
{
LOG_ENTRY();
//Check signature
return iELFHeader.e_ident[EI_MAG0] == ELFMAG0 &&
iELFHeader.e_ident[EI_MAG1] == ELFMAG1 &&
iELFHeader.e_ident[EI_MAG2] == ELFMAG2 &&
iELFHeader.e_ident[EI_MAG3] == ELFMAG3;
}
/**
* Provides the ELF header of this file
* @param aELFHeader Holds the ELF header after the call
*/
EXPORT_C void CSELFEditor::GetELFHeader(Elf32_Ehdr& aELFHeader)
{
LOG_ENTRY();
aELFHeader = iELFHeader;
}
/**
* Caches the program headers from the file into this object
* @leave One of the system wide codes
*/
void CSELFEditor::CacheProgramHeadersL()
{
LOG_ENTRY();
Elf32_Phdr progHeader;
TPtr8 phdrPtr((TUint8*)&progHeader, sizeof(Elf32_Phdr));
TUint nextPh = iELFHeader.e_phoff;
for(TUint i = 0; i < iELFHeader.e_phnum; i++)
{
User::LeaveIfError(iELFFile.Read(nextPh, phdrPtr));
iProgramHeaders.AppendL(progHeader);
nextPh += sizeof(Elf32_Phdr);
}
}
/**
* Inserts variant specific data into the ELF file
* @param aVarData The binary data to be inserted into the ELF file
* @leave One of the system wide codes
*/
EXPORT_C void CSELFEditor::InsertVariantSpecificDataL(const TDesC8& aVarData)
{
LOG_ENTRY();
//Store the data in the raw data array, and record its position to associate with the new section
iRawData->AppendL(aVarData);
TUint position = iRawData->Count() - 1;
//Now create the variant sepcific data dhdr and structure
TSELFSegment newSegment;
newSegment.iPhdr.p_type = PT_NOTE;
newSegment.iPhdr.p_offset = 0; //Fill in when we write the file
newSegment.iPhdr.p_vaddr = 0;
newSegment.iPhdr.p_paddr = 0;
newSegment.iPhdr.p_filesz =0;
newSegment.iPhdr.p_memsz = 0;
newSegment.iPhdr.p_flags = 0;
newSegment.iPhdr.p_align = sizeof(TUint);
newSegment.iDhdr.d_name = 0; //Fill in when we write the file (we need the string table)
newSegment.iDhdr.d_type = ESYM_NOTE_VARIANT_DATA;
newSegment.iDhdr.d_version = 0; //Fill in when we write the file (we need the string table)
newSegment.iDhdr.d_elemnum = 1;
newSegment.iDhdr.d_descrsz = sizeof(Sym32_variant_spec_data);
Sym32_variant_spec_data* variantData = (Sym32_variant_spec_data*)(&newSegment.iType);
variantData->es_data = position; //This data is in the iRawData until the write
variantData->es_size = aVarData.Size();
iNewSegments.AppendL(newSegment);
++iELFHeader.e_phnum;
}
/**
* Commits any changes made in the CSELFEditor to the ELF file
* @leave One of the system wide codes
*/
EXPORT_C void CSELFEditor::WriteELFUpdatesL()
{
LOG_ENTRY();
//There may be nothing to do
if(iNewSegments.Count() == 0)
return;
//Create tmp file
TBuf<KMaxFileName> tmpFilename;
RFile tmpFile;
User::LeaveIfError(tmpFile.Temp(iFsSession, KTempFileLocation, tmpFilename, EFileWrite));
CleanupClosePushL(tmpFile);
//Log file name
TPtr8 smallName((TUint8*)tmpFilename.Ptr(), 2*tmpFilename.Length(), 2*tmpFilename.Length());
LOG_MSG2("\tWriteELFUpdatesL() --> Writing new temporary updates to [%S]", &smallName);
TUint numberofPhdrs = 0;
//Leave space for elf header plus program header table at start
TUint spaceToLeave =+ sizeof(Elf32_Ehdr) + (iNewSegments.Count() + iProgramHeaders.Count() ) * sizeof(Elf32_Phdr);
PutEmptySpaceAtEndOfFileL(tmpFile, spaceToLeave);
TUint phdrLoc = sizeof(Elf32_Ehdr); //phdr table starts just after ELF header
TUint dataLoc = spaceToLeave;
LOG_MSG("WriteELFUpdatesL --> Copying existing program headers to the tmp file");
//Store new program headers as we go
RArray<Elf32_Phdr> newProgramHeaders;
{
Elf32_Phdr phdr;
TPtr8 phdrPtr((TUint8*)&phdr, sizeof(Elf32_Phdr), sizeof(Elf32_Phdr));
for(TUint i = 0; i < iProgramHeaders.Count(); i++)
{
phdr = iProgramHeaders[i];
//Now we put the neccesary data after the phdr table
if(phdr.p_type == PT_LOAD && phdr.p_filesz != 0 && phdr.p_offset != 0)
{
phdr.p_offset = CopyFromELFFileL(phdr.p_offset, phdr.p_filesz, tmpFile, dataLoc);
dataLoc += phdr.p_filesz;
}
else if(phdr.p_type == PT_NOTE)
{
//Read the symbian descriptor
READ_STRUCTL(Sym32_dhdr, symd, iELFFile, phdr.p_offset);
//TODO: The fact that we need this *MAY* indicate flaws in SELF format. It would be nice
//to be able to copy a bit that was completely described by the dhdr
if(symd.d_type == ESYM_NOTE_REG)
{
//registers cant just be blindly copied as they contain offsets that need updating
TUint sizeWritten = 0;
phdr.p_offset = CopyRegistersL(tmpFile, phdr.p_offset, dataLoc, sizeWritten);
dataLoc += sizeWritten;
}
else if(symd.d_type == ESYM_NOTE_VARIANT_DATA)
{
//Variant data cant be blindly copied either as they have offsets too
TUint sizeWritten = 0;
phdr.p_offset = CopyVariantDataL(tmpFile, phdr.p_offset, dataLoc, sizeWritten);
dataLoc += sizeWritten;
}
//special case - needs updating so do after everything else
else if(symd.d_type == ESYM_NOTE_STR)
{
continue;
}
else
{
TUint sizetoCopy = sizeof(Sym32_dhdr) + symd.d_descrsz * symd.d_elemnum;
phdr.p_offset = CopyFromELFFileL(phdr.p_offset, sizetoCopy, tmpFile, dataLoc);
dataLoc += sizetoCopy;
}
}
//Write the updated program header
User::LeaveIfError(tmpFile.Write(phdrLoc, phdrPtr));
phdrLoc += sizeof(Elf32_Phdr);
newProgramHeaders.AppendL(phdr);
++numberofPhdrs;
}
LOG_MSG2("WriteELFUpdatesL --> Copied [%d] existing program headers (minus string table)", numberofPhdrs);
}
//Now we add the new segments
//This is for the string table
TBuf8<KMaxFileName> varDataBuf;
varDataBuf.Format(_L8("CORE.SYMBIAN.VARDATA"));
TUint versionIndex = iStringTable->GetIndex(KSymbianElfCoreDumpVersionV2);
for(TUint i = 0; i < iNewSegments.Count(); i++)
{
TSELFSegment segment = iNewSegments[i];
//Update the program header and the d_hdr
segment.iPhdr.p_offset = dataLoc;
TInt index = iStringTable->AddStringL(varDataBuf);
segment.iDhdr.d_name = (index == KErrNotFound) ? ESYM_STR_UNDEF : index;
segment.iDhdr.d_version = versionIndex;
Sym32_variant_spec_data* variantData = (Sym32_variant_spec_data*)(&segment.iType);
TUint dataIndex = variantData->es_data;
variantData->es_data = dataLoc + sizeof(Sym32_variant_spec_data) + sizeof(Sym32_dhdr);
//Write the phdr
TPtr8 nphdrPtr((TUint8*)&segment.iPhdr, sizeof(Elf32_Phdr), sizeof(Elf32_Phdr));
User::LeaveIfError(tmpFile.Write(phdrLoc, nphdrPtr));
newProgramHeaders.AppendL(segment.iPhdr);
phdrLoc += sizeof(Elf32_Phdr);
++numberofPhdrs;
//Write the dhdr
TPtr8 ndhdrPtr((TUint8*)&segment.iDhdr, sizeof(Sym32_dhdr), sizeof(Sym32_dhdr));
User::LeaveIfError(tmpFile.Write(dataLoc, ndhdrPtr));
dataLoc += sizeof(Sym32_dhdr);
//Write the var struct
TPtr8 nvarHdr((TUint8*)&segment.iType, sizeof(Sym32_variant_spec_data), sizeof(Sym32_variant_spec_data));
User::LeaveIfError(tmpFile.Write(dataLoc, nvarHdr));
dataLoc += sizeof(Sym32_variant_spec_data);
//Write the data
User::LeaveIfError(tmpFile.Write(dataLoc, (*iRawData)[dataIndex]));
dataLoc += variantData->es_size;
}
//Write the string info
Elf32_Phdr sphdr;
TPtr8 sphdrPtr((TUint8*)&sphdr, sizeof(Elf32_Phdr), sizeof(Elf32_Phdr));
sphdr.p_type = PT_NOTE;
sphdr.p_offset = WriteStringInfoL(tmpFile, dataLoc);
sphdr.p_vaddr = 0;
sphdr.p_paddr = 0;
sphdr.p_filesz = 0;
sphdr.p_memsz = 0;
sphdr.p_flags = 0;
sphdr.p_align = 4;
User::LeaveIfError(tmpFile.Write(phdrLoc, sphdrPtr));
newProgramHeaders.Append(sphdr);
phdrLoc += sizeof(Elf32_Phdr);
++numberofPhdrs;
//Last thing, is to finally update the ELF header and write it
iELFHeader.e_phoff = sizeof(Elf32_Ehdr);
iELFHeader.e_phnum = numberofPhdrs;
LOG_MSG("\tWriting final ELF Header");
TPtr8 hdrPtr((TUint8*)&iELFHeader, sizeof(Elf32_Ehdr), sizeof(Elf32_Ehdr));
User::LeaveIfError(tmpFile.Write(0, hdrPtr));
tmpFile.Flush();
CleanupStack::PopAndDestroy(&tmpFile);
TBuf<KMaxFileName> origFilename;
iELFFile.FullName(origFilename);
iELFFile.Close();
SwapFilesL(tmpFilename, origFilename);
//Open the file again for further use and reset data structs
User::LeaveIfError(iELFFile.Open(iFsSession, origFilename, EFileWrite));
iNewSegments.Reset();
iProgramHeaders.Close();
iProgramHeaders = newProgramHeaders; //Update with latest p hdrs
}
/**
* Writes the string info at specified offset
* This writes the Sym32_dhdr and the string info
* @param aFile File to write to
* @param aOffset Position in file to write to. This is updated and finishes at the next free point to
* write to in this file
* @leave One of the system wide codes
* @return Offset in the file where this was written to (the initial value of aOffset)
*/
TUint CSELFEditor::WriteStringInfoL(RFile aFile, TUint& aOffset)
{
LOG_ENTRY();
TUint writeStart = aOffset;
Sym32_dhdr dhdr;
TPtr8 dhdrPtr((TUint8*)&dhdr, sizeof(Sym32_dhdr), sizeof(Sym32_dhdr));
TInt index = iStringTable->GetIndex(KStr);
dhdr.d_name = (index == KErrNotFound) ? ESYM_STR_UNDEF : index;
dhdr.d_descrsz = iStringTable->GetSize();
dhdr.d_type = ESYM_NOTE_STR;
dhdr.d_version = iStringTable->GetIndex(KSymbianElfCoreDumpVersionV2);
dhdr.d_elemnum = 1;
//Write the dhdr
User::LeaveIfError(aFile.Write(aOffset, dhdrPtr));
aOffset += sizeof(Sym32_dhdr);
//Write the string info
TText8* buf = iStringTable->GetAllStrings();
TUint size = iStringTable->GetSize();
TPtr8 data((TUint8*)buf, size, size);
User::LeaveIfError(aFile.Write(aOffset, data));
aOffset += size;
return writeStart;
}
/**
* Copies the registers to aFile sensibly, updating the offsets accordingly
* @param aFile Destination file
* @param aSrcRead Place in src file where d_hdr starts
* @param aDestWrite Destination to write to
* @leave One of the system wide codes
*/
TUint CSELFEditor::CopyRegistersL(RFile aFile, TUint aSrcRead, TUint aDestWrite, TUint& aSizeWritten)
{
LOG_ENTRY();
aSizeWritten = 0;
TUint srcpos = aSrcRead;
TUint destpos = aDestWrite;
//Write the dhdr, it wont change
READ_STRUCTL(Sym32_dhdr, dhdr, iELFFile, srcpos);
CopyFromELFFileL(srcpos, sizeof(Sym32_dhdr), aFile, destpos);
srcpos += sizeof(Sym32_dhdr);
destpos += sizeof(Sym32_dhdr);
//And the reginfod struct
READ_STRUCTL(Sym32_reginfod, reginfo, iELFFile, srcpos);
CopyFromELFFileL(srcpos, sizeof(Sym32_reginfod), aFile, destpos);
srcpos += sizeof(Sym32_reginfod);
destpos += sizeof(Sym32_reginfod);
RBuf8 regVals;
regVals.CreateL(reginfo.rid_num_registers * sizeof(TUint64));
regVals.CleanupClosePushL();
//Now we need to go through the individual register values. They are offset to somewhere and
//we need to figure out where we will be putting them first
TUint regoffset = destpos + (reginfo.rid_num_registers * sizeof(Sym32_regdatad) );
for(TUint i = 0; i < reginfo.rid_num_registers; i++)
{
READ_STRUCTL(Sym32_regdatad, regdata, iELFFile, srcpos);
srcpos += sizeof(Sym32_regdatad);
//update the offset
TUint srcOffset = regdata.rd_data;
regdata.rd_data = regoffset;
regoffset += sizeof(TUint64);
//Write it to the file
TPtr8 dataPtr((TUint8*)®data, sizeof(Sym32_regdatad), sizeof(Sym32_regdatad));
User::LeaveIfError(aFile.Write(destpos, dataPtr));
destpos += sizeof(Sym32_regdatad);
//Read the appropriate value
TUint32 regValue = 0;
TPtr8 regValuePtr((TUint8*)®Value, sizeof(TUint64), sizeof(TUint64));
switch(reginfo.rid_repre)
{
case ESYM_REG_8:
User::LeaveIfError(iELFFile.Read(srcOffset, regValuePtr, sizeof(TUint8)));
break;
case ESYM_REG_16:
User::LeaveIfError(iELFFile.Read(srcOffset, regValuePtr, sizeof(TUint16)));
break;
case ESYM_REG_32:
User::LeaveIfError(iELFFile.Read(srcOffset, regValuePtr, sizeof(TUint32)));
break;
case ESYM_REG_64:
User::LeaveIfError(iELFFile.Read(srcOffset, regValuePtr, sizeof(TUint64)));
break;
default:
regValue = 0;
break;
}
regValuePtr.SetLength(sizeof(TUint64));
regVals.Append(regValuePtr);
}
//Now write the values
User::LeaveIfError(aFile.Write(destpos, regVals));
destpos += regVals.Size();
CleanupStack::PopAndDestroy(®Vals);
aSizeWritten = destpos - aDestWrite;
return aDestWrite;
}
/**
* Copies the variant data to aFile sensibly, updating the offsets accordingly
* @param aFile Destination file
* @param aSrcRead Place in src file where d_hdr starts
* @param aDestWrite Destination to write to
* @leave One of the system wide codes
*/
TUint CSELFEditor::CopyVariantDataL(RFile aFile, TUint aSrcRead, TUint aDestWrite, TUint& aSizeWritten)
{
LOG_ENTRY();
aSizeWritten = 0;
TUint srcpos = aSrcRead;
TUint destpos = aDestWrite;
//Write the dhdr, it wont change
READ_STRUCTL(Sym32_dhdr, dhdr, iELFFile, srcpos);
CopyFromELFFileL(srcpos, sizeof(Sym32_dhdr), aFile, destpos);
srcpos += sizeof(Sym32_dhdr);
destpos += sizeof(Sym32_dhdr);
//And the var data struct
READ_STRUCTL(Sym32_variant_spec_data, varData, iELFFile, srcpos);
varData.es_data = destpos + sizeof(Sym32_variant_spec_data);
TPtr8 varDataPtr((TUint8*)&varData, sizeof(Sym32_variant_spec_data), sizeof(Sym32_variant_spec_data));
User::LeaveIfError(aFile.Write(destpos, varDataPtr));
srcpos += sizeof(Sym32_variant_spec_data);
destpos += sizeof(Sym32_variant_spec_data);
//And the data
CopyFromELFFileL(srcpos, varData.es_size, aFile, destpos);
srcpos += varData.es_size;
destpos += varData.es_size;
aSizeWritten = destpos - aDestWrite;
return aDestWrite;
}
/**
* Copies a part of the ELF file into a destination file
* @param aStartPoint Point in file to start copying
* @param aSize Amount to copy
* @param aDestinationFile Destination file to copy to
* @param aDestWrite Position in destination to write to
* @return Place in file where this has been written
* @leave One of the System wide codes
*/
TUint CSELFEditor::CopyFromELFFileL(TUint aStartPoint, TUint aSize, RFile aDestinationFile, TUint aDestWrite)
{
TUint readpos = aStartPoint;
TUint endpoint = aStartPoint + aSize;
TUint destpos = aDestWrite;
//Use free memory/10 for our buffering
TInt block = 0;
TInt freemem = User::Available(block);
TInt maxfilecopysize = freemem/10;
RBuf8 copybuf;
copybuf.CreateL(maxfilecopysize);
copybuf.CleanupClosePushL();
while(readpos < endpoint)
{
TUint readsize = maxfilecopysize;
if(readpos + readsize > endpoint)
readsize = endpoint - readpos;
if(readsize != copybuf.MaxLength())
copybuf.ReAllocL(readsize);
User::LeaveIfError(iELFFile.Read(readpos, copybuf, readsize));
User::LeaveIfError(aDestinationFile.Write(destpos, copybuf));
copybuf.Zero();
destpos += readsize;
readpos += readsize;
}
CleanupStack::PopAndDestroy(©buf);
return aDestWrite;
}
/**
* Caches the string table in source ELF file into our string info table object
* @leaves One of the system wide codes
*/
void CSELFEditor::CacheStringTableL()
{
LOG_ENTRY();
for(TUint i = 0; i < iProgramHeaders.Count(); i++)
{
Elf32_Phdr phdr = iProgramHeaders[i];
READ_STRUCTL(Sym32_dhdr, dhdr, iELFFile, phdr.p_offset);
if(dhdr.d_type == ESYM_NOTE_STR)
{
iStringTableDhdr = dhdr;
RBuf8 stringData;
stringData.CreateL(dhdr.d_descrsz);
stringData.CleanupClosePushL();
User::LeaveIfError(iELFFile.Read(phdr.p_offset + sizeof(Sym32_dhdr), stringData));
iStringTable = CStringInfoTableV2::NewL(stringData);
CleanupStack::PopAndDestroy(&stringData);
return;
}
}
}
/**
* Utility function to leave space in the file
* @param aFile
* @param aSize
*/
void CSELFEditor::PutEmptySpaceAtEndOfFileL(RFile aFile, TUint aSize)
{
LOG_ENTRY();
RBuf8 empty;
empty.CreateL(aSize);
empty.CleanupClosePushL();
empty.SetLength(aSize);
LOG_MSG2("\tPutEmptySpaceAtEndOfFileL --> Leaving [0x%X] bytes", aSize);
User::LeaveIfError(aFile.Write(empty));
CleanupStack::PopAndDestroy(&empty);
}
/**
* Swaps 2 files and deletes the original destination
* @leave One of the system wide codes
*/
void CSELFEditor::SwapFilesL(const TDesC& aSrc, const TDesC& aDest)
{
LOG_ENTRY();
//1. Back up the destination file in case anything fails
TBuf<KMaxFileName> backupName;
backupName.Copy(aDest);
backupName.Append(_L(".bak"));
CFileMan* fmanager = CFileMan::NewL(iFsSession);
CleanupStack::PushL(fmanager);
User::LeaveIfError(fmanager->Rename(aDest, backupName));
//2. Rename the src file to the dest file
TInt err = fmanager->Move(aSrc, aDest);
if(KErrNone != err)
{
//rename failed so restore original file
TPtr8 dest8((TUint8*)aDest.Ptr(), 2*aDest.Length(), 2*aDest.Length());
RDebug::Printf("\nFailed to move the tmp file so restoring original file [%S]", &dest8);
User::LeaveIfError(fmanager->Rename(backupName, aDest));
User::Leave(err);
}
//3. Delete the backup file file
User::LeaveIfError(fmanager->Delete(backupName));
CleanupStack::PopAndDestroy(fmanager);
}