c-rpm

RPM Haskell Bindings

This example demonstrates generating Haskell bindings for RPM Package Manager, a powerful package management system.

Prerequisites

Using Nix Shell

This example includes a shell.nix file that provides all necessary dependencies for building RPM from source. The shell environment includes:

Build tools:

• cmake - Build system generator
• pkg-config - Helper tool for compile/link flags
• scdoc - Documentation generator

RPM dependencies:

• popt - Command line option parsing
• libarchive - Multi-format archive and compression library
• sqlite - Database engine for RPM database
• zstd - Fast compression algorithm
• elfutils - ELF object file access library
• xz - LZMA compression utilities
• lua - Scripting language for RPM
• zlib - Compression library
• bzip2 - Compression library
• readline - Command line editing
• file - File type identification
• libcap - POSIX capabilities library
• audit - Linux audit framework
• libselinux - SELinux runtime library
• dbus - Message bus system
• rpm-sequoia - OpenPGP implementation (from nixos-unstable)

Tip

If you are using Nix or NixOS, please also have a look at our hs-bindgen Nix tutorial.

If not using Nix at all, take a look at the INSTALL file for more details on the instructions of how to build rpm.

Running the Example

Building RPM from Source

According to the instructions in INSTALL:

# On the `rpm` folder
mkdir _build
cd _build
cmake ..
make
make install

Once all these steps have completed successfully the libraries will be under rpm/_build/_install/lib64.

Linking Against the C Library

The .cabal file includes extra-libraries: rpm, rpmio, which tells the linker to link against both librpm.so and librpmio.so. RPM is split into multiple libraries, and both are needed for the bindings to work correctly.

Generating the bindings

./generate-and-run.sh

Generating the Include Graph

This script will already generate the bindings by their right order, i.e. the header include dependency order. If for any reason the rpm library updated, then it might be necessary to change the generate-and-run script so that it follows the right order.

To visualize the header dependencies, you can generate an include graph using hs-bindgen-cli:

cd examples/c-rpm
cabal run hs-bindgen-cli -- info include-graph \
    -I rpm/include \
    -o output-graph.md \
    rpm/rpmlib.h

This generates a Mermaid diagram showing all header includes and their dependencies. You can visualize it at mermaid.live or in any Markdown viewer that supports Mermaid diagrams (like GitHub).