Elf

ELF Format: Static Linking and Dynamic Linking ELF format used in different phases of program execution 1. Object Files (.o) These are intermediate compilation artifacts - not executable on their own. ELF type: ET_REL (relocatable). Key characteristics: Result of compiling a single source file Contain unresolved symbols (references to functions/variables defined elsewhere) Relocatable code that hasn’t been assigned final memory addresses Must be linked together to create executables or libraries Cannot be directly executed Let’s do an exercise to understand the role of ELF in object files (.o) ...

ELF Format: Sections and Section Header Table In the previous post, we explored Program Headers and Segments - the runtime view of an ELF file. Now we’ll look at Section Headers and Sections - the link-time and debugging view. What Are Sections? Sections are the link-time view of an ELF file. While segments tell the operating system how to load and execute a program, sections organize the file’s contents for: ...

ELF Format: Segments and Program Header Table After understanding the ELF Header, the next critical component is the Program Header Table. This table describes segments - the portions of the file that will be loaded into memory when the program executes. What Are Segments? Segments are the runtime view of an ELF file. While sections (which we’ll cover later) are used during linking and debugging, segments are what the operating system cares about when loading and executing a program. ...

ELF Format: ELF Header What is ELF? ELF (Executable and Linkable Format) is the standard binary format used by Unix-like systems (Linux, BSD, etc.) for: Executable files (a.out, /bin/ls) Object files (.o) Shared libraries (.so) Core dumps It’s a container format that describes: What parts of the file get loaded into memory, Where execution starts, How relocations and dynamic linking are handled. Contains useful information for the debuggers. General Structure of an ELF File An ELF file is organized into several key components that serve different purposes during compilation, linking, and execution. ...