Module openj9.dtfj

Package com.ibm.j9ddr.corereaders.elf

Class ELFFileReader

java.lang.Object

com.ibm.j9ddr.corereaders.elf.ELFFileReader

Direct Known Subclasses:

ELF32FileReader, ELF64FileReader

public abstract class ELFFileReader
extends Object

Field Summary

Fields

Modifier and Type	Field	Description
static final int	ARCH_AARCH64
static final int	ARCH_AMD64
static final int	ARCH_ARM
static final int	ARCH_IA32
static final int	ARCH_IA64
static final int	ARCH_PPC32
static final int	ARCH_PPC64
static final int	ARCH_RISCV64
static final int	ARCH_S390
static final int	AT_ENTRY
static final int	AT_HWCAP
static final int	AT_NULL
static final int	AT_PLATFORM
static final int	DT_DEBUG
static final int	DT_NULL
static final int	DT_SONAME
static final int	DT_STRTAB
static final int	EI_NIDENT
static final int	ELF_NOTE_HEADER_SIZE
static final int	ELF_PRARGSZ
static final int	ELFCLASS32
static final int	ELFCLASS64
static final byte	ELFDATA2LSB
static final byte	ELFDATA2MSB
static final short	ET_CORE
static final short	ET_DYN
static final short	ET_EXEC
static final int	ET_HIOS
static final int	ET_HIPROC
static final int	ET_LOOS
static final int	ET_LOPROC
static final short	ET_NONE
static final short	ET_NUM
static final short	ET_REL
protected ImageInputStream	is
static final int	NT_AUXV
static final int	NT_HGPRS
static final int	NT_PRPSINFO
static final int	NT_PRSTATUS
protected String	sourceName

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	ELFFileReader(File file, ByteOrder byteOrder)
protected	ELFFileReader(ImageInputStream in, long offset, long size)

Method Summary

Modifier and Type	Method	Description
protected abstract int	addressSizeBits()
boolean	canResolveAddress(long address)	Search the program header table to see whether it can successfully resolve an address into a file offset.
void	close()
ByteOrder	getByteOrder()
ProgramHeaderEntry	getDynamicTableEntry()	Search the program header table for the dynamic entry.
static ELFFileReader	getELFFileReader(File file)
static ELFFileReader	getELFFileReader(ImageInputStream in)
static ELFFileReader	getELFFileReaderWithOffset(ImageInputStream in, long offset, long limit)
File	getFile()	Returns the file from which this reader is reading.
short	getMachineType()
Collection<? extends IMemorySource>	getMemoryRanges(long baseAddress, List<com.ibm.j9ddr.corereaders.elf.SectionHeaderEntry> sectionHeaderEntries, Map<Long,String> sectionHeaderStringTable)	Iterate through the sections that were already loaded and create a list of memory source objects for them.
List<? extends ProgramHeaderEntry>	getProgramHeaderEntries()
Properties	getProperties()
List<com.ibm.j9ddr.corereaders.elf.SectionHeaderEntry>	getSectionHeaderEntries()
Map<Long,String>	getSectionHeaderStringTable()
String	getSourceName()
ImageInputStream	getStream()	Gets the data stream for this reader
List<? extends ISymbol>	getSymbols(long baseAddress, boolean useUnallocatedSections)	Obtain the symbols from a core reader, offset by baseAddress.
boolean	is64Bit()
boolean	isCompatibleWith(ELFFileReader otherReader)	Perform a quick check on two ELF readers to see if they represent the same library.
static boolean	isELF(byte[] signature)
boolean	isExecutable()	Examine the ELF header to determine if this file is an executable or not.
boolean	isTruncated()	Are any parts of the core file known to be missing?
protected abstract long	padToWordBoundary(long address)
byte	readByte()
byte[]	readBytes(int len)
protected abstract long	readElfWord()
protected abstract com.ibm.j9ddr.corereaders.elf.Address	readElfWordAsAddress()
void	readFully(byte[] b, int off, int len)
int	readInt()
long	readLong()
protected abstract ProgramHeaderEntry	readProgramHeaderEntry()
short	readShort()
String	readSONAME(ELFFileReader coreFileReader)	Assume the entry given refers to a loaded library or program and find and return its name or null if it couldn't be determined.
String	readString()	Reads a string from the readers current position until it is terminated by a null (0) byte.
protected abstract List<com.ibm.j9ddr.corereaders.elf.ELFSymbol>	readSymbolsAt(com.ibm.j9ddr.corereaders.elf.SectionHeaderEntry entry)
boolean	sectionHeaderMapsToProgramHeader(com.ibm.j9ddr.corereaders.elf.SectionHeaderEntry section)
void	seek(long pos)

Methods declared in class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

ELF_NOTE_HEADER_SIZE

public static final int ELF_NOTE_HEADER_SIZE

See Also:

• Constant Field Values

EI_NIDENT

public static final int EI_NIDENT

See Also:

• Constant Field Values

ELFDATA2LSB

public static final byte ELFDATA2LSB

See Also:

• Constant Field Values

ELFDATA2MSB

public static final byte ELFDATA2MSB

See Also:

• Constant Field Values

ELFCLASS32

public static final int ELFCLASS32

See Also:

• Constant Field Values

ELFCLASS64

public static final int ELFCLASS64

See Also:

• Constant Field Values

ELF_PRARGSZ

public static final int ELF_PRARGSZ

See Also:

• Constant Field Values

ARCH_IA32

public static final int ARCH_IA32

See Also:

• Constant Field Values

ARCH_PPC32

public static final int ARCH_PPC32

See Also:

• Constant Field Values

ARCH_PPC64

public static final int ARCH_PPC64

See Also:

• Constant Field Values

ARCH_S390

public static final int ARCH_S390

See Also:

• Constant Field Values

ARCH_ARM

public static final int ARCH_ARM

See Also:

• Constant Field Values

ARCH_IA64

public static final int ARCH_IA64

See Also:

• Constant Field Values

ARCH_AMD64

public static final int ARCH_AMD64

See Also:

• Constant Field Values

ARCH_AARCH64

public static final int ARCH_AARCH64

See Also:

• Constant Field Values

ARCH_RISCV64

public static final int ARCH_RISCV64

See Also:

• Constant Field Values

DT_NULL

public static final int DT_NULL

See Also:

• Constant Field Values

DT_DEBUG

public static final int DT_DEBUG

See Also:

• Constant Field Values

DT_SONAME

public static final int DT_SONAME

See Also:

• Constant Field Values

DT_STRTAB

public static final int DT_STRTAB

See Also:

• Constant Field Values

ET_NONE

public static final short ET_NONE

See Also:

• Constant Field Values

ET_REL

public static final short ET_REL

See Also:

• Constant Field Values

ET_EXEC

public static final short ET_EXEC

See Also:

• Constant Field Values

ET_DYN

public static final short ET_DYN

See Also:

• Constant Field Values

ET_CORE

public static final short ET_CORE

See Also:

• Constant Field Values

ET_NUM

public static final short ET_NUM

See Also:

• Constant Field Values

ET_LOOS

public static final int ET_LOOS

See Also:

• Constant Field Values

ET_HIOS

public static final int ET_HIOS

See Also:

• Constant Field Values

ET_LOPROC

public static final int ET_LOPROC

See Also:

• Constant Field Values

ET_HIPROC

public static final int ET_HIPROC

See Also:

• Constant Field Values

NT_PRSTATUS

public static final int NT_PRSTATUS

See Also:

• Constant Field Values

NT_PRPSINFO

public static final int NT_PRPSINFO

See Also:

• Constant Field Values

NT_AUXV

public static final int NT_AUXV

See Also:

• Constant Field Values

NT_HGPRS

public static final int NT_HGPRS

See Also:

• Constant Field Values

AT_NULL

public static final int AT_NULL

See Also:

• Constant Field Values

AT_ENTRY

public static final int AT_ENTRY

See Also:

• Constant Field Values

AT_PLATFORM

public static final int AT_PLATFORM

See Also:

• Constant Field Values

AT_HWCAP

public static final int AT_HWCAP

See Also:

• Constant Field Values

is

protected ImageInputStream is

sourceName

protected String sourceName

Constructor Details

ELFFileReader

protected ELFFileReader(File file,
 ByteOrder byteOrder)
                 throws IOException,
InvalidDumpFormatException

Throws:

IOException

InvalidDumpFormatException

ELFFileReader

protected ELFFileReader(ImageInputStream in,
 long offset,
 long size)
                 throws IOException,
InvalidDumpFormatException

Throws:

IOException

InvalidDumpFormatException

Method Details

padToWordBoundary

protected abstract long padToWordBoundary(long address)

readProgramHeaderEntry

protected abstract ProgramHeaderEntry readProgramHeaderEntry()
                                                      throws IOException

Throws:

IOException

readElfWord

protected abstract long readElfWord()
                             throws IOException

Throws:

IOException

readElfWordAsAddress

protected abstract com.ibm.j9ddr.corereaders.elf.Address readElfWordAsAddress()
                                                                       throws IOException

Throws:

IOException

readSymbolsAt

protected abstract List<com.ibm.j9ddr.corereaders.elf.ELFSymbol> readSymbolsAt(com.ibm.j9ddr.corereaders.elf.SectionHeaderEntry entry)
                                                                        throws IOException

Throws:

IOException

addressSizeBits

protected abstract int addressSizeBits()

close

public void close()
           throws IOException

Throws:

IOException

getSourceName

public String getSourceName()

getELFFileReader

public static ELFFileReader getELFFileReader(File file)
                                      throws IOException,
InvalidDumpFormatException

Throws:

IOException

InvalidDumpFormatException

getELFFileReader

public static ELFFileReader getELFFileReader(ImageInputStream in)
                                      throws IOException,
InvalidDumpFormatException

Throws:

IOException

InvalidDumpFormatException

getELFFileReaderWithOffset

public static ELFFileReader getELFFileReaderWithOffset(ImageInputStream in,
 long offset,
 long limit)
                                                throws IOException,
InvalidDumpFormatException

Throws:

IOException

InvalidDumpFormatException

isELF

public static boolean isELF(byte[] signature)

canResolveAddress

public boolean canResolveAddress(long address)

Search the program header table to see whether it can successfully resolve an address into a file offset.

If it returns true then it will be safe to call seekToAddress without an IOException being thrown. If it returns false, it will not.

Parameters:

address - virtual address

Returns:

true or false according to whether the address will resolve

getSymbols

public List<? extends ISymbol> getSymbols(long baseAddress,
 boolean useUnallocatedSections)
                                   throws IOException

Obtain the symbols from a core reader, offset by baseAddress.

Parameters:

baseAddress - the base address to offset symbols from.

useUnallocatedSections - whether to include symbols from unallocated sections. (true if reading from a library on disk, false if from a loaded library in the core file.)

Returns:

Throws:

IOException

getMemoryRanges

public Collection<? extends IMemorySource> getMemoryRanges(long baseAddress,
 List<com.ibm.j9ddr.corereaders.elf.SectionHeaderEntry> sectionHeaderEntries,
 Map<Long,String> sectionHeaderStringTable)
                                                    throws IOException

Iterate through the sections that were already loaded and create a list of memory source objects for them. Abandon the process if it is not possible to find the section header string table. This is one of the last sections and if it cannot be found it is a good indicator that at least part of the section header table has been overwritten. Since it is usually impossible to say where the overwriting starts it is safest to abandon it all. This is only an issue when working with a dump that does not have the original library files attached to it.

Parameters:

baseAddress -

Returns:

List of memory sources

Throws:

IOException

sectionHeaderMapsToProgramHeader

public boolean sectionHeaderMapsToProgramHeader(com.ibm.j9ddr.corereaders.elf.SectionHeaderEntry section)

getSectionHeaderStringTable

public Map<Long,String> getSectionHeaderStringTable()
                                             throws IOException

Throws:

IOException

is64Bit

public boolean is64Bit()

readBytes

public byte[] readBytes(int len)
                 throws IOException

Throws:

IOException

getMachineType

public short getMachineType()

getProgramHeaderEntries

public List<? extends ProgramHeaderEntry> getProgramHeaderEntries()

getSectionHeaderEntries

public List<com.ibm.j9ddr.corereaders.elf.SectionHeaderEntry> getSectionHeaderEntries()

getStream

public ImageInputStream getStream()
                           throws IOException

Gets the data stream for this reader

Returns:

an ImageInputStream for this reader

Throws:

IOException

getFile

public File getFile()

Returns the file from which this reader is reading.

Returns:

File or null if this reader is reading from a stream

getProperties

public Properties getProperties()

readInt

public int readInt()
            throws IOException

Throws:

IOException

readByte

public byte readByte()
              throws IOException

Throws:

IOException

seek

public void seek(long pos)
          throws IOException

Throws:

IOException

getByteOrder

public ByteOrder getByteOrder()

readShort

public short readShort()
                throws IOException

Throws:

IOException

readLong

public long readLong()
              throws IOException

Throws:

IOException

readFully

public void readFully(byte[] b,
 int off,
 int len)
               throws IOException

Throws:

IOException

readString

public String readString()

Reads a string from the readers current position until it is terminated by a null (0) byte. Bytes are read and converted to an ASCII string. string. If readByte throws an exception, null will be returned.

Returns:

the null terminated sting at the readers current position or null

Throws:

IOException

getDynamicTableEntry

public ProgramHeaderEntry getDynamicTableEntry()

Search the program header table for the dynamic entry. There should be only one of these Typically it is within the first few entries, often the third, so this is not expensive

Returns:

the program header table entry for the dynamic table

isExecutable

public boolean isExecutable()

Examine the ELF header to determine if this file is an executable or not. Often it will instead be a shared library.

Returns:

true if the file is an executable

isTruncated

public boolean isTruncated()

Are any parts of the core file known to be missing?

readSONAME

public String readSONAME(ELFFileReader coreFileReader)

Assume the entry given refers to a loaded library or program and find and return its name or null if it couldn't be determined. This method does not throw exceptions as we are seeking around the core file which could be damaged or may come from a version of linux which doesn't leave this information available, just do our best.

Parameters:

ELFFileReader - for the core file as a whole

Returns:

the SONAME (library name) or null

isCompatibleWith

public boolean isCompatibleWith(ELFFileReader otherReader)

Perform a quick check on two ELF readers to see if they represent the same library. otherReader is the one we hope is better that this reader. This is not the same as checking they are equal as we hope the other reader actually has more information in.

Parameters:

otherReader - another ELFFileReader to compare against this one.