dl_iterate_phdr - Linux

Overview

dl_iterate_phdr is a utility that parses ELF executable files and iterates over their program headers. It provides a structured way to examine and extract information from the headers, which are vital for understanding the layout and organization of the executable. This command is particularly useful in debugging, code analysis, and security audits.

Syntax

dl_iterate_phdr [-h] [-v] executable_file

Options/Flags

  • -h, –help: Display help and usage information.
  • -v, –verbose: Enable verbose output, displaying detailed information about each program header.

Examples

Simple usage:

dl_iterate_phdr example.elf

Extracting specific header data:

dl_iterate_phdr -v example.elf | grep "p_type: PT_LOAD"

Common Issues

  • Permission denied: Ensure you have read permissions for the ELF file specified.
  • Invalid ELF file: Verify that the provided file is a valid ELF executable.
  • No program headers: Some ELF files may not contain program headers. Use elfdump to inspect the file structure.

Integration

dl_iterate_phdr can be integrated with other tools for advanced tasks:

  • Disassembly with IDA Pro: Load the executable into IDA Pro and use -Sdl_iterate_phdr <file> to parse the program headers and show the segmentation in the debugger.
  • Binary patching with radare2: Use dl_iterate_phdr to identify and modify specific program headers with rabin2 -q -a <executable_file>.

Related Commands

  • readelf: Displays ELF file information, including program headers.
  • elfdump: Outputs a detailed description of the ELF file structure.
  • file: Determines the file type of an ELF executable.
  • objdump: Disassembles and displays the contents of ELF files.