Class ELFFileReader

java.lang.Object
com.ibm.j9ddr.corereaders.elf.ELFFileReader
Direct Known Subclasses:
ELF32FileReader, ELF64FileReader
public abstract class ELFFileReader extends Object

  • Field Details

  • Constructor Details

  • 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.