The Global Offset Table, or GOT, is a section of a

computer program A computer program is a sequence or set of instructions in a programming language for a computer to execute. Computer programs are one component of software, which also includes documentation and other intangible components. A computer program ...

's (executables and shared libraries) memory used to enable computer program code compiled as an

ELF An elf () is a type of humanoid supernatural being in Germanic mythology and folklore. Elves appear especially in North Germanic mythology. They are subsequently mentioned in Snorri Sturluson's Icelandic Prose Edda. He distinguishes "ligh ...

file to run correctly,

independent Independent or Independents may refer to: Arts, entertainment, and media Artist groups * Independents (artist group), a group of modernist painters based in the New Hope, Pennsylvania, area of the United States during the early 1930s * Independ ...

of the memory address where the program's code or data is loaded at runtime. It maps

symbols A symbol is a mark, sign, or word that indicates, signifies, or is understood as representing an idea, object, or relationship. Symbols allow people to go beyond what is known or seen by creating linkages between otherwise very different conc ...

in programming code to their corresponding absolute memory addresses to facilitate Position Independent Code (PIC) and Position Independent Executables (PIE) which are loaded to a different memory address each time the program is started. The runtime memory address, also known as absolute memory address of variables and functions is unknown before the program is started when PIC or PIE code is run so cannot be hardcoded during compilation by a

compiler In computing, a compiler is a computer program that translates computer code written in one programming language (the ''source'' language) into another language (the ''target'' language). The name "compiler" is primarily used for programs that ...

. The Global Offset Table is represented as the .got and .got.plt sections in an ELF file which are loaded into the program's memory at startup. The operating system's

dynamic linker In computing, a dynamic linker is the part of an operating system that loads and links the shared libraries needed by an executable when it is executed (at " run time"), by copying the content of libraries from persistent storage to RAM, filling ...

updates the global offset table relocations (symbol to absolute memory addresses) at program startup or as symbols are accessed. It is the mechanism that allows

shared libraries In computer science, a library is a collection of non-volatile resources used by computer programs, often for software development. These may include configuration data, documentation, help data, message templates, pre-written code and su ...

(.so) to be relocated to a different memory address at startup and avoid memory address conflicts with the main program or other shared libraries, and to harden computer program code from exploitation.

References

Computer programming {{compu-prog-stub