init

.devcontainer/Dockerfile

@@ -0,0 +1,28 @@
+FROM fedora:latest AS devcontainer
+ARG UID="1000"
+ARG GID="1000"
+ARG BASENAME="workdir"
+
+# setup packages
+USER root
+RUN dnf update -y
+RUN dnf install -y dnf5-devel libdnf5-devel libdnf5-cli-devel openssh-server vim cmake gcc g++ git just
+
+# setup environment
+RUN ssh-keygen -A
+RUN sed -i "s|#Port 22|Port 2222|g" /etc/ssh/sshd_config
+RUN sed -i "s|AuthorizedKeysFile.*|AuthorizedKeysFile /etc/ssh/authorized_keys|g" /etc/ssh/sshd_config
+RUN --mount=type=secret,id=key,target=/root/id.pub \
+  cp /root/id.pub /etc/ssh/authorized_keys
+
+# setup user and permissions
+RUN groupadd -g $GID dev
+RUN useradd -u $UID -g $GID -lN dev
+RUN chown dev:dev /etc/ssh/ssh_host* /etc/ssh/authorized_keys /etc/ssh/sshd_config
+USER dev
+WORKDIR /volume/${BASENAME}
+EXPOSE 2222/tcp
+CMD ["/usr/sbin/sshd", "-D"]
+
+# use docker exec or SSH to access container OR
+# use docker compose to specify entrypoint

.gitignore

@@ -0,0 +1,13 @@
+build/
+CMakeLists.txt.user
+CMakeCache.txt
+CMakeFiles
+CMakeScripts
+Testing
+Makefile
+cmake_install.cmake
+install_manifest.txt
+compile_commands.json
+CTestTestfile.cmake
+_deps
+CMakeUserPresets.json

CMakeLists.txt

@@ -0,0 +1,31 @@
+cmake_minimum_required(VERSION 3.6)
+
+project(lifi LANGUAGES CXX C VERSION 0.1.0)
+
+# includes
+include(GNUInstallDirs)
+
+find_package(PkgConfig REQUIRED)
+
+# C++ standard
+set(CMAKE_CXX_STANDARD 20)
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
+
+# Give inline methods hidden visibility by default
+set(CMAKE_VISIBILITY_INLINES_HIDDEN ON)
+
+# warnings
+add_compile_options(-Wall -Wextra -Werror)
+add_compile_options(-Wcast-align -Wformat-nonliteral -Wmissing-format-attribute -Wredundant-decls -Wsign-compare -Wsign-conversion -Wtype-limits -Wuninitialized -Wwrite-strings)
+add_compile_options(-Werror=unused-result -Wodr)
+
+# not sure about the conversion warnings being errors; review later
+add_compile_options(-Wconversion)
+
+# linker options
+if(NOT CMAKE_CXX_COMPILER_ID MATCHES "Clang")
+    # clang doesn't support this option
+    add_compile_options(-Wl,--as-needed)
+endif()
+
+add_subdirectory("src")

Justfile

@@ -0,0 +1,37 @@
+alias dev := devcontainer
+alias t := transaction
+
+workdir := `pwd`
+basename := `basename $(pwd)`
+dockerfile := '.devcontainer/Dockerfile'
+container := basename + '-devcontainer'
+uid := `id -u`
+gid := `id -g`
+image := container + '-img'
+ssh_key := env('HOME') + '/.ssh/id_rsa.pub'
+
+# for use in dev container
+build: 
+  mkdir -p build
+  cd build && cmake .. && make
+
+# test a transaction
+transaction:
+  docker exec -u root -it {{container}} dnf reinstall libdnf5 --setopt=pluginpath=build/src \
+    --setopt=pluginconfpath=src -y
+
+clean:
+  docker container stop {{container}} || :
+  docker container rm {{container}} || :
+  docker image rm {{image}} || :
+  rm -rf build
+
+# (re)start Docker dev container
+devcontainer:
+  (docker container ls --all | grep -q {{container}} && docker container stop {{container}} \
+    && docker container rm {{container}}) || :
+  docker build --secret id=key,src={{ssh_key}} --build-arg UID={{uid}} --build-arg GID={{gid}} \
+    --build-arg BASENAME={{basename}} -t {{image}} -f {{dockerfile}} .
+  docker container create --name {{container}} -v {{workdir}}:/volume/{{basename}} \
+    -p 2222:2222 {{image}}
+  docker container start {{container}}

src/CMakeLists.txt

@@ -0,0 +1,11 @@
+add_library(lifi MODULE lifi.cpp)
+
+# disable the 'lib' prefix in order to create lifi.so
+set_target_properties(lifi PROPERTIES PREFIX "")
+set_target_properties(lifi PROPERTIES OUTPUT_NAME "lifi")
+
+pkg_check_modules(LIBDNF5 REQUIRED libdnf5)
+target_link_libraries(lifi PRIVATE ${LIBDNF5_LIBRARIES})
+
+install(TARGETS lifi LIBRARY DESTINATION "${CMAKE_INSTALL_FULL_LIBDIR}/libdnf5/plugins/")
+install(FILES "lifi.conf" DESTINATION "${CMAKE_INSTALL_FULL_SYSCONFDIR}/dnf/libdnf5-plugins")

src/lifi.conf

@@ -0,0 +1,6 @@
+[main]
+name = lifi
+enabled = 1
+
+[new]
+custom_thing = hi there

src/lifi.cpp

@@ -0,0 +1,93 @@
+#include <libdnf5-cli/defs.h>
+#include <libdnf5/base/base.hpp>
+#include <libdnf5/base/transaction.hpp>
+#include <libdnf5/base/transaction_package.hpp>
+#include <libdnf5/common/exception.hpp>
+#include <libdnf5/conf/config_parser.hpp>
+#include <libdnf5/defs.h>
+#include <libdnf5/plugin/iplugin.hpp>
+
+#include <iostream>
+
+using namespace libdnf5;
+
+namespace {
+
+constexpr const char *PLUGIN_NAME = "lifi";
+constexpr plugin::Version PLUGIN_VERSION{0, 1, 0};
+
+constexpr const char *attrs[]{"author.name", "author.email", "description",
+                              nullptr};
+constexpr const char *attrs_value[]{"Bryson Steck", "bryson@steck.dev",
+                                    "a LIcense FIlter for dnf"};
+
+class Lifi final : public plugin::IPlugin {
+public:
+  ConfigParser config;
+  Lifi(libdnf5::plugin::IPluginData &data, libdnf5::ConfigParser &config)
+      : IPlugin(data) {
+    config = config;
+    this->config.read(
+        get_base().get_config().get_pluginconfpath_option().get_value() +
+        "/lifi.conf");
+  }
+  virtual ~Lifi() = default;
+
+  PluginAPIVersion get_api_version() const noexcept override {
+    return PLUGIN_API_VERSION;
+  }
+
+  const char *get_name() const noexcept override { return PLUGIN_NAME; }
+
+  plugin::Version get_version() const noexcept override {
+    return PLUGIN_VERSION;
+  }
+
+  const char *const *get_attributes() const noexcept override { return attrs; }
+
+  const char *get_attribute(const char *attribute) const noexcept override {
+    for (size_t i = 0; attrs[i]; ++i) {
+      if (std::strcmp(attribute, attrs[i]) == 0) {
+        return attrs_value[i];
+      }
+    }
+    return nullptr;
+  }
+
+  void pre_transaction(
+      [[maybe_unused]] const libdnf5::base::Transaction &transaction) override {
+    std::cout << "----- executing Lifi::pre_transaction() method -----"
+              << std ::endl;
+    auto packages = transaction.get_transaction_packages();
+
+    for (auto pkg : packages) {
+      std::cout << pkg.get_package().get_license() << std::endl;
+    }
+    std::cout << config.get_value("new", "custom_thing") << std::endl;
+  }
+
+private:
+};
+
+} // namespace
+
+PluginAPIVersion libdnf_plugin_get_api_version(void) {
+  return PLUGIN_API_VERSION;
+}
+
+const char *libdnf_plugin_get_name(void) { return PLUGIN_NAME; }
+
+plugin::Version libdnf_plugin_get_version(void) { return PLUGIN_VERSION; }
+
+plugin::IPlugin *
+libdnf_plugin_new_instance([[maybe_unused]] LibraryVersion library_version,
+                           libdnf5::plugin::IPluginData &data,
+                           libdnf5::ConfigParser &parser) try {
+  return new Lifi(data, parser);
+} catch (...) {
+  return nullptr;
+}
+
+void libdnf_plugin_delete_instance(plugin::IPlugin *plugin_object) {
+  delete plugin_object;
+}