Package ghidra.app.util.bin.format.elf

Class ElfSymbol

java.lang.Object
ghidra.app.util.bin.format.elf.ElfSymbol
public class ElfSymbol extends Object
A class to represent the ELF 32bit and 64bit Symbol data structures. 
 typedef struct {
     Elf32_Word      st_name;     //Symbol name (string tbl index)
     Elf32_Addr      st_value;    //Symbol value
     Elf32_Word      st_size;     //Symbol size
     unsigned char   st_info;     //Symbol type and binding
     unsigned char   st_other;    //Symbol visibility
     Elf32_Section   st_shndx;    //Section index
 } Elf32_Sym;
 
 typedef struct {
     Elf64_Word       st_name;    //Symbol name (string tbl index)
     unsigned char    st_info;    //Symbol type and binding
     unsigned char    st_other;   //Symbol visibility
     Elf64_Section    st_shndx;   //Section index
     Elf64_Addr       st_value;   //Symbol value
     Elf64_Xword      st_size;    //Symbol size
 } Elf64_Sym;

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    static final String
    FORMATTED_NO_NAME
     
    static final byte
    STB_GLOBAL
    Global symbols are visible to all object files being combined.
    static final byte
    STB_GNU_UNIQUE
    Symbol is unique in namespace.
    static final byte
    STB_LOCAL
    Local symbols are not visible outside the object file containing their definition.
    static final byte
    STB_WEAK
    Weak symbols resemble global symbols, but their definitions have lower precedence.
    static final byte
    STT_COMMON
    An uninitialized common block
    static final byte
    STT_FILE
    The symbol's name gives the name of the source file associated with the object file.
    static final byte
    STT_FUNC
    The symbol is associated with a function or other executable code.
    static final byte
    STT_NOTYPE
    The symbol's type is not specified.
    static final byte
    STT_OBJECT
    The symbol is associated with a data object, such as a variable, an array, etc.
    static final byte
    STT_RELC
    Symbol is in support of complex relocation.
    static final byte
    STT_SECTION
    The symbol is associated with a section.
    static final byte
    STT_SRELC
    Symbol is in support of complex relocation (signed value).
    static final byte
    STT_TLS
    In object files: st_value contains offset from the beginning of the section In DSOs: st_value contains offset in the TLS initialization image (inside of .tdata)
    static final byte
    STV_DEFAULT
    Default symbol visibility rules
    static final byte
    STV_HIDDEN
    Sym unavailable in other modules
    static final byte
    STV_INTERNAL
    Processor specific hidden class
    static final byte
    STV_PROTECTED
    Not preemptible, not exported

  • Constructor Summary

    Constructors
    Constructor
    Description
    ElfSymbol()
    Construct a new special null symbol which corresponds to symbol index 0.
    ElfSymbol(BinaryReader reader, int symbolIndex, ElfSymbolTable symbolTable, ElfHeader header)
    Construct a normal ElfSymbol.

  • Method Summary

    Modifier and Type
    Method
    Description
    boolean
    equals(Object obj)
     
    byte
    getBind()
    Returns the symbol's binding.
    int
    getExtendedSectionHeaderIndex()
    Get the extended symbol section index value when st_shndx (getSectionHeaderIndex()) has a value of SHN_XINDEX.
    String
    getFormattedName()
    Returns the formatted string name for this symbol.
    byte
    getInfo()
    This member specifies the symbol's type and binding attributes.
    int
    getName()
    This member holds an index into the object file's symbol string table, which holds the character representations of the symbol names.
    String
    getNameAsString()
    Returns the actual string name for this symbol.
    byte
    getOther()
    This member currently holds 0 and has no defined meaning.
    short
    getSectionHeaderIndex()
    Get the raw section index value (st_shndx) for this symbol.
    long
    getSize()
    Many symbols have associated sizes.
    ElfSymbolTable
    getSymbolTable()
    Get the symbol table containing this symbol
    int
    getSymbolTableIndex()
    Get the index of this symbol within the corresponding symbol table.
    byte
    getType()
    Returns the symbol's binding.
    long
    getValue()
    This member gives the value of the associated symbol.
    byte
    getVisibility()
    Returns the symbol's visibility.
    int
    hashCode()
     
    boolean
    hasProcessorSpecificSymbolSectionIndex()
    Determine if st_shndx is within the reserved processor-specific index range
    void
    initSymbolName(BinaryReader reader, ElfStringTable stringTable)
    Initialize the string name of the symbol.
    boolean
    isAbsolute()
    Returns true if the symbol has an absolute value that will not change because of relocation.
    boolean
    isCommon()
    The symbol labels a common block that has not yet been allocated.
    boolean
    isExternal()
    Returns true if this is an external symbol.
    boolean
    isFile()
    Returns true if this symbol defines a file.
    boolean
    isFunction()
    Returns true if this symbol defines a function.
    boolean
    isGlobal()
    Returns true if this symbol is global.
    boolean
    isLocal()
    Returns true if this symbol is local.
    boolean
    isNoType()
    Returns true if this symbol's type is not specified.
    boolean
    isObject()
    Returns true if this symbol defines an object.
    boolean
    isSection()
    Returns true if this symbol defines a section.
    boolean
    isTLS()
    Returns true if this symbol defines a thread-local symbol.
    boolean
    isWeak()
    Returns true if this symbol is weak.
    String
    toString()
     

    Methods inherited from class java.lang.Object

    clone, finalize, getClass, notify, notifyAll, wait, wait, wait

  • Field Details

    • FORMATTED_NO_NAME

      public static final String FORMATTED_NO_NAME
      See Also:

    • STB_LOCAL

      public static final byte STB_LOCAL
      Local symbols are not visible outside the object file containing their definition.
      See Also:

    • STB_GLOBAL

      public static final byte STB_GLOBAL
      Global symbols are visible to all object files being combined.
      See Also:

    • STB_WEAK

      public static final byte STB_WEAK
      Weak symbols resemble global symbols, but their definitions have lower precedence.
      See Also:

    • STB_GNU_UNIQUE

      public static final byte STB_GNU_UNIQUE
      Symbol is unique in namespace.
      See Also:

    • STT_NOTYPE

      public static final byte STT_NOTYPE
      The symbol's type is not specified.
      See Also:

    • STT_OBJECT

      public static final byte STT_OBJECT
      The symbol is associated with a data object, such as a variable, an array, etc.
      See Also:

    • STT_FUNC

      public static final byte STT_FUNC
      The symbol is associated with a function or other executable code.
      See Also:

    • STT_SECTION

      public static final byte STT_SECTION
      The symbol is associated with a section. (Used for relocation and normally have STB_LOCAL binding.)
      See Also:

    • STT_FILE

      public static final byte STT_FILE
      The symbol's name gives the name of the source file associated with the object file.
      See Also:

    • STT_COMMON

      public static final byte STT_COMMON
      An uninitialized common block
      See Also:

    • STT_TLS

      public static final byte STT_TLS
      In object files: st_value contains offset from the beginning of the section In DSOs: st_value contains offset in the TLS initialization image (inside of .tdata)
      See Also:

    • STT_RELC

      public static final byte STT_RELC
      Symbol is in support of complex relocation.
      See Also:

    • STT_SRELC

      public static final byte STT_SRELC
      Symbol is in support of complex relocation (signed value).
      See Also:

    • STV_DEFAULT

      public static final byte STV_DEFAULT
      Default symbol visibility rules
      See Also:

    • STV_INTERNAL

      public static final byte STV_INTERNAL
      Processor specific hidden class
      See Also:

    • STV_HIDDEN

      public static final byte STV_HIDDEN
      Sym unavailable in other modules
      See Also:

    • STV_PROTECTED

      public static final byte STV_PROTECTED
      Not preemptible, not exported
      See Also:

  • Constructor Details

    • ElfSymbol

      public ElfSymbol()
      Construct a new special null symbol which corresponds to symbol index 0.

    • ElfSymbol

      public ElfSymbol(BinaryReader reader, int symbolIndex, ElfSymbolTable symbolTable, ElfHeader header) throws IOException
      Construct a normal ElfSymbol. Warning! the routine initSymbolName() must be called on the symbol later to initialize the string name. This is a performance enhancement.
      Parameters:
      reader - to read symbol entry at current position (reader is not retained, position is altered)
      symbolIndex - index of the symbol to read
      symbolTable - symbol table to associate the symbol to
      header - ELF header
      Throws:
      IOException - if an IO error occurs during parse

  • Method Details

    • initSymbolName

      public void initSymbolName(BinaryReader reader, ElfStringTable stringTable)
      Initialize the string name of the symbol. NOTE: This routine MUST be called for each ELFSymbol after the elf symbols have been created. This is done separately from the initial symbol entry read because the string names are in a separate location. If they are read at the same time the reading buffer will jump around and significantly degrade reading performance.
      Parameters:
      reader - to read from (position remains unchanged)
      stringTable - stringTable to initialize symbol name

    • getSymbolTable

      public ElfSymbolTable getSymbolTable()
      Get the symbol table containing this symbol
      Returns:
      symbol table

    • getSymbolTableIndex

      public int getSymbolTableIndex()
      Get the index of this symbol within the corresponding symbol table.
      Returns:
      index of this symbol within the corresponding symbol table

    • isNoType

      public boolean isNoType()
      Returns true if this symbol's type is not specified.
      Returns:
      true if this symbol's type is not specified

    • hashCode

      public int hashCode()
      Overrides:
      hashCode in class Object

    • equals

      public boolean equals(Object obj)
      Overrides:
      equals in class Object

    • isLocal

      public boolean isLocal()
      Returns true if this symbol is local. Local symbols are not visible outside the object file containing their definition. Local symbols of the same name may exist in multiple files without colliding.
      Returns:
      true if this symbol is local

    • isGlobal

      public boolean isGlobal()
      Returns true if this symbol is global. Global symbols are visible to all object files being combined. One object file's definition of a global symbol will satisfy another file's undefined reference to the same global symbol.
      Returns:
      true if this symbol is global

    • isWeak

      public boolean isWeak()
      Returns true if this symbol is weak. Weak symbols resemble global symbols, but their definitions have lower precedence.
      Returns:
      true if this symbol is weak

    • isExternal

      public boolean isExternal()
      Returns true if this is an external symbol. A symbol is considered external if it's binding is global and it's size is zero.
      Returns:
      true if this is an external symbol

    • isSection

      public boolean isSection()
      Returns true if this symbol defines a section.
      Returns:
      true if this symbol defines a section

    • isFunction

      public boolean isFunction()
      Returns true if this symbol defines a function.
      Returns:
      true if this symbol defines a function

    • isObject

      public boolean isObject()
      Returns true if this symbol defines an object.
      Returns:
      true if this symbol defines an object

    • isFile

      public boolean isFile()
      Returns true if this symbol defines a file.
      Returns:
      true if this symbol defines a file

    • isTLS

      public boolean isTLS()
      Returns true if this symbol defines a thread-local symbol.
      Returns:
      true if this symbol defines a thread-local symbol

    • isAbsolute

      public boolean isAbsolute()
      Returns true if the symbol has an absolute value that will not change because of relocation.
      Returns:
      true if the symbol value will not change due to relocation

    • isCommon

      public boolean isCommon()
      The symbol labels a common block that has not yet been allocated. The symbol's value gives alignment constraints, similar to a section's sh_addralign member. That is, the link editor will allocate the storage for the symbol at an address that is a multiple of st_value. The symbol's size tells how many bytes are required.
      Returns:
      true if this is a common symbol

    • getInfo

      public byte getInfo()
      This member specifies the symbol's type and binding attributes.
      Returns:
      the symbol's type and binding attributes

    • getVisibility

      public byte getVisibility()
      Returns the symbol's visibility. For example, default.
      Returns:
      the symbol's visibility

    • getBind

      public byte getBind()
      Returns the symbol's binding. For example, global.
      Returns:
      the symbol's binding

    • getType

      public byte getType()
      Returns the symbol's binding. For example, section.
      Returns:
      the symbol's binding

    • getName

      public int getName()
      This member holds an index into the object file's symbol string table, which holds the character representations of the symbol names. If the value is non-zero, it represents a string table index that gives the symbol name. Otherwise, the symbol table entry has no name.
      Returns:
      the index to the symbol's name

    • getNameAsString

      public String getNameAsString()
      Returns the actual string name for this symbol. The symbol only stores an byte index into the string table where the name string is located.
      Returns:
      the actual string name for this symbol (may be null or empty string)

    • getFormattedName

      public String getFormattedName()
      Returns the formatted string name for this symbol. If the name is blank or can not be resolved due to a missing string table the literal string <no name> will be returned. the name string is located.
      Returns:
      the actual string name for this symbol or the literal string <no name>

    • getOther

      public byte getOther()
      This member currently holds 0 and has no defined meaning.
      Returns:
      no defined meaning

    • getSectionHeaderIndex

      public short getSectionHeaderIndex()
      Get the raw section index value (st_shndx) for this symbol. Special values (SHN_LORESERVE and higher) must be treated properly. The value SHN_XINDEX indicates that the extended value must be used to obtained the actual section index (see getExtendedSectionHeaderIndex()).
      Returns:
      the st_shndx section index value

    • getExtendedSectionHeaderIndex

      public int getExtendedSectionHeaderIndex()
      Get the extended symbol section index value when st_shndx (getSectionHeaderIndex()) has a value of SHN_XINDEX. This requires a lookup into a table defined by an associated SHT_SYMTAB_SHNDX section.
      Returns:
      extended symbol section index value

    • hasProcessorSpecificSymbolSectionIndex

      public boolean hasProcessorSpecificSymbolSectionIndex()
      Determine if st_shndx is within the reserved processor-specific index range
      Returns:
      true if specified symbol section index corresponds to a processor specific value in the range SHN_LOPROC..SHN_HIPROC, else false

    • getSize

      public long getSize()
      Many symbols have associated sizes. For example, a data object's size is the number of bytes contained in the object. This member holds 0 if the symbol has no size or an unknown size.
      Returns:
      the symbol's size

    • getValue

      public long getValue()
      This member gives the value of the associated symbol. Depending on the context, this may be an absolute value, an address, etc.
      Returns:
      the symbol's value

    • toString

      public String toString()
      Overrides:
      toString in class Object
      See Also: