davea42 / readelfobj-code

This provides programs that read and print basic object information on three different object formats. Elf,MachO, and PE. They work regardless of endian differences. No object-format specific libraries are used, only the standard C library is required.

README.md

Last update: August 5, 2024

The distribution consists entirely of C source files (along with GNU configure scripts to configure and build executables). Builds and works on Linux, MacOS, and Windows msys2 and on across all of those the programs can read all the object formats supported.

Requires python3 and a bash or sh shell.

If unsure what object format a file might be, the object_detector will tell you. (On linux and MacOs the 'file' command will do that too.)

Contents

object_detector

A program that reads a minimal amount of object header content (for any of the supported object types) and prints basic information (file type, offset size, and endianness) about each file.

readelfobj

A program that reads elf object files and prints the header information. It also checks for certain errors including wasted space in the object files. It also dumps Elf relocation sections, Elf symtab sections, and the Elf dynamic section.

readobjpe

A program that reads PE object executables or dlls and prints header information (mainly focused on sections that may be DWARF data).

readobjmacho

A program that reads MacOS dSYM files and prints header information. (mainly focused on sections that may be DWARF data).

The only library used is standard C libc.

The code does not depend on any Elf, Mach-o, or Windows libraries or headers, it just depends on a basic POSIX/unix/Linux set of headers plus libc (or equivalent).

The test directory contains numerous examples of using the programs.

To dump DWARF section contents one should use dwarfdump (a part of the libdwarf-code github project) or GNU readelf (in GNU binutils).

For Msys2 (Windows): The configure option --enable-nonstandardprintf may be required to avoid errors in certain printf.

RUNNING MAKE CHECK from a release

Download the release from

https://github.com/davea42/readelfobj-code

and unpack

#For example:
tar xf readelfobj-1.0.0.xz
cd  readelfobj-1.0.0 
./configure --enable-wall
make
make check
#Building in a directory separate from
#the download also works

RUNNING MAKE CHECK from git clone:

Using a git clone is not recommended as the autogen.sh step requires one have the GNU autotools installed. We build outside the source tree to keep the tree clean.

#git clone https://github.com/davea42/readelfobj-code
#Linux/Unix/MacOS/MinGW(Windows)
src=/path/to/readelfobj-code
cd $src
sh autogen.sh

bld=/tmp/robld 
rm -rf $bld 
mkdir $bld
cd $bld
# may not be necessary.
sh $src/configure --enable-wall
make check 

To update configure, update configure.ac and/or one or more Makefile.am and do, in the top level directory: autoreconf -vif You will need several GNU autotools installed for this autoreconf to work.