File formats for executables

• Common file formats for executables/ binaries
• Jargon
• Pre-requisite installations
  • Mingw-w64
• Exercises
  • Files for exercise
  • Exercise #1: Analyze an intermediate Object File Format
  • Exercise #2: Generate and analyze the executable format
• Challenges
• Quiz

Common file formats for executables/ binaries

Jargon

Other names: executable code, executable file, executable program, executable, binary

Pre-requisite installations

Mingw-w64

Mingw-w64 is an advancement of the original mingw.org project, created to support the GCC compiler on Windows systems. It also has a port for Linux to generate Windows executables.

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sudo apt-get install mingw-w64-x86-64-dev
sudo apt-get install mingw-w64-i686-dev 

Exercises

Files for exercise

add.c

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int add(int a, int b)
{
  int sum=0;
  sum = a+b;
  return sum;
}

main.c

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int main(int argc, char const *argv[])
{
  int res;
  res = add(10,20);
	printf("Result: %d\n", res);
  return 0;
}

Exercise #1: Analyze an intermediate Object File Format

Compile add.c using following command. This will generate the intermediate object file add.o. Use the file command to note the file type.

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gcc -c -o add.o add.c

file add.o add.c

As it is observed the add.o is stored in ELF format and add.c is a ASCII format as it holds the source code.

Note: Since add.o is an intermediate object file we will be unable to execute it.

Exercise #2: Generate and analyze the executable format

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# Generate the ELF executable format for Unices
gcc -o main main.c add.c

# Generate the PE executable format for Windows
i686-w64-mingw32-gcc -o main.exe main.c add.c

# Observe the executable formats
file main main.exe

Challenges

Quiz

Take a quiz to provide your answers to above challenges