AppImageCrafters · azubieta · May 24, 2022 · May 25, 2022 · May 25, 2022 · May 25, 2022
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
@@ -35,6 +35,8 @@ jobs:
           mkdir -p ${{runner.workspace}}/dist
           cp src/apprun/AppRun ${{runner.workspace}}/dist/AppRun-$BUILD_TYPE-$TARGET_ARCH
           cp src/hooks/libapprun_hooks.so ${{runner.workspace}}/dist/libapprun_hooks-$BUILD_TYPE-$TARGET_ARCH.so
+          cp src/modules/check-glibc ${{runner.workspace}}/dist/check-glibc-$BUILD_TYPE-$TARGET_ARCH
+          cp src/modules/check-glibstdc++ ${{runner.workspace}}/dist/check-glibstdc++-$BUILD_TYPE-$TARGET_ARCH
 
       - name: Upload Artifacts ${{ env.TARGET_ARCH }}
         uses: actions/[email protected]

diff --git a/.github/workflows/pre-release.yml b/.github/workflows/pre-release.yml
@@ -33,6 +33,8 @@ jobs:
           mkdir -p ${{runner.workspace}}/dist
           cp src/apprun/AppRun ${{runner.workspace}}/dist/AppRun-$BUILD_TYPE-$TARGET_ARCH
           cp src/hooks/libapprun_hooks.so ${{runner.workspace}}/dist/libapprun_hooks-$BUILD_TYPE-$TARGET_ARCH.so
+          cp src/modules/check-glibc ${{runner.workspace}}/dist/check-glibc-$BUILD_TYPE-$TARGET_ARCH
+          cp src/modules/check-glibstdc++ ${{runner.workspace}}/dist/check-glibstdc++-$BUILD_TYPE-$TARGET_ARCH
 
       - name: Upload Artifacts ${{ env.TARGET_ARCH }}
         uses: actions/[email protected]

diff --git a/.github/workflows/tagged-release.yml b/.github/workflows/tagged-release.yml
@@ -33,6 +33,8 @@ jobs:
           mkdir -p ${{runner.workspace}}/dist
           cp src/apprun/AppRun ${{runner.workspace}}/dist/AppRun-$BUILD_TYPE-$TARGET_ARCH
           cp src/hooks/libapprun_hooks.so ${{runner.workspace}}/dist/libapprun_hooks-$BUILD_TYPE-$TARGET_ARCH.so
+          cp src/modules/check-glibc ${{runner.workspace}}/dist/check-glibc-$BUILD_TYPE-$TARGET_ARCH
+          cp src/modules/check-glibstdc++ ${{runner.workspace}}/dist/check-glibstdc++-$BUILD_TYPE-$TARGET_ARCH
 
       - name: Upload Artifacts ${{ env.TARGET_ARCH }}
         uses: actions/[email protected]

diff --git a/CMakeLists.txt b/CMakeLists.txt
@@ -1,12 +1,14 @@
 project(AppImageExecWrapper)
 cmake_minimum_required(VERSION 3.2)
 set(CMAKE_C_STANDARD 99)
+set(CMAKE_CXX_STANDARD 14)
 
 if (${CMAKE_BUILD_TYPE} MATCHES Profile)
     message(STATUS "Coverage and profile build flags enabled")
     set(CMAKE_C_FLAGS "-fprofile-arcs -ftest-coverage")
 endif (${CMAKE_BUILD_TYPE} MATCHES Profile)
 
+include(cmake/get_libconfig.cmake)
 add_subdirectory(src)
 
 if (BUILD_TESTING)

diff --git a/cmake/get_libconfig.cmake b/cmake/get_libconfig.cmake
@@ -0,0 +1,31 @@
+cmake_minimum_required(VERSION 3.11)
+include(ExternalProject)
+
+# Get the libconfig library
+externalproject_add(
+    libconfig.git
+    GIT_REPOSITORY https://github.com/hyperrealm/libconfig.git
+    GIT_TAG v1.7.3
+    GIT_SHALLOW On
+    UPDATE_DISCONNECTED On
+    CMAKE_ARGS
+    -DCMAKE_INSTALL_PREFIX=/usr
+    -DBUILD_EXAMPLES=Off
+    -DBUILD_TESTS=Off
+    -DBUILD_SHARED_LIBS=Off
+    -DCMAKE_TOOLCHAIN_FILE:FILEPATH=${CMAKE_TOOLCHAIN_FILE}
+    -DCMAKE_INSTALL_PREFIX:PATH=<INSTALL_DIR>
+)
+
+ExternalProject_Get_Property(libconfig.git install_dir)
+include_directories(${install_dir}/include)
+
+
+add_library(libconfig STATIC IMPORTED)
+set_property(TARGET libconfig PROPERTY IMPORTED_LOCATION ${install_dir}/lib/libconfig.a)
+
+add_library(libconfig++ STATIC IMPORTED)
+set_property(TARGET libconfig++ PROPERTY IMPORTED_LOCATION ${install_dir}/lib/libconfig++.a)
+
+add_dependencies(libconfig libconfig.git)
+add_dependencies(libconfig++ libconfig.git)
diff --git a/cmake/i386-toolchain.cmake b/cmake/i386-toolchain.cmake
@@ -1,21 +1,23 @@
-# this one is important
-SET(CMAKE_SYSTEM_NAME Linux)
-#this one not so much
-SET(CMAKE_SYSTEM_VERSION 1)
+set(CMAKE_SYSTEM_NAME Linux)
+set(CMAKE_SYSTEM_PROCESSOR i386)
 
-# specify the cross compiler
-SET(CMAKE_C_COMPILER /usr/bin/gcc)
-set(CMAKE_C_COMPILER_ARG1 "-m32")
-SET(CMAKE_CXX_COMPILER /usr/bin/g++)
-set(CMAKE_CXX_COMPILER_ARG1 "-m32")
+set(CMAKE_C_FLAGS "-m32")
+set(CMAKE_CXX_FLAGS "-m32")
 
-# where is the target environment
-SET(CMAKE_FIND_ROOT_PATH /usr/lib/i386-linux-gnu)
-set(CMAKE_IGNORE_PATH /usr/lib/x86_64-linux-gnu/ /usr/lib/x86_64-linux-gnu/lib/)
+# CMAKE_SHARED_LINKER_FLAGS, CMAKE_STATIC_LINKER_FLAGS etc. must not be set, but CMAKE_EXE_LINKER_FLAGS is necessary
+set(CMAKE_EXE_LINKER_FLAGS "-m32")
 
-# search for programs in the build host directories
-SET(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
+set(DEPENDENCIES_CFLAGS "-m32")
+set(DEPENDENCIES_CPPFLAGS "-m32")
+set(DEPENDENCIES_LDFLAGS "-m32")
 
-# for libraries and headers in the target directories
-SET(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
-SET(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
+# host = target system
+# build = build system
+# both must be specified
+set(EXTRA_CONFIGURE_FLAGS "--host=i686-pc-linux-gnu" "--build=x86_64-pc-linux-gnu")
+
+# may help with some rare issues
+set(CMAKE_PREFIX_PATH /usr/lib/i386-linux-gnu)
+
+# makes sure that at least on Ubuntu pkg-config will search for the :i386 packages
+set(ENV{PKG_CONFIG_PATH} /usr/lib/i386-linux-gnu/pkgconfig/)
diff --git a/docs/MODULES.md b/docs/MODULES.md
@@ -0,0 +1,72 @@
+Modules
+=======
+
+A module is a part of the bundle that will only be used at runtime if the host system doesn't provide a certain feature.
+Each module will include a "check" app (or script). This will be executed by the AppRun to verify if the system has the 
+required feature. The module will be used only if this check fails.
+
+Modules provide a way of configuring the bundle at runtime. This is required to switch between the system and bundled 
+libraries depending on the system configuration. The simplest example is glibc, applications need to always use the
+latest version therefore we must check if the system provides an older one in order to use the module.
+
+-------------
+Specification
+-------------
+
+An AppDir may contain given set of modules at `$APPDIR/opt/`. Each module will contain the following components:
+
+- "check" app
+- "config" file
+- binaries and resources to be optionally used at runtime
+
+check
+-----
+The check application has the sole purpose of guessing whether the system provides certain feature. It will be executed
+on launch and must return a fast a possible. The application must exit with code 0 if the system has the expected
+feature otherwise must return a non-zero value.
+
+The module will be enabled only if the system doesn't have the required feature (which means that the check returned a 
+non-zero value).
+
+config file
+-----------
+
+The config file will follow the [libconfig format](https://hyperrealm.github.io/libconfig/libconfig_manual.html) and
+will contain the settings required to activate the bundle at runtime. It may also include other information required by
+other components such as the check binary. It will have the following structure:
+
+- `check`: optional group, may contain data required by the check app.
+- `module`: mandatory group, module runtime settings
+
+  - `library_paths`: optional string list, module library paths
+  - `path_mappings`: optional string pair list, path mapping instructions
+  - `environment`: optional map, environment variables
+  - `runtime_dir`: optional string, working directory to be set on execve instructions (reserved for the glibc module)
+
+Example:
+
+```shell
+version = "1.0";
+
+# check app configuration
+check:
+{
+  required_lib_version = "2.0.0";
+};
+
+# module runtime configuration
+module:
+{
+  # library paths to be set
+  library_paths = ( "${APPDIR}/opt/module_id/lib", "${APPDIR}/opt/module_id/usr/lib");
+
+  # path_mappings to be set
+  path_mappings = [ "/bin/app:${APPDIR}/opt/module_id/bin/app" ] ;
+
+  # additional environment variables to be set 
+  environment:
+  {
+    MY_VAR: "MY_VAR_VALUE";
+  };
+};
+```
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
@@ -1,3 +1,4 @@
 add_subdirectory(common)
 add_subdirectory(hooks)
 add_subdirectory(apprun)
+add_subdirectory(modules)
diff --git a/src/apprun/CMakeLists.txt b/src/apprun/CMakeLists.txt
@@ -1,26 +1,25 @@
 add_library(
-        apprun_objects OBJECT
+    apprun_objects OBJECT
 
-        ../hooks/environment.c
-        runtime_environment.c
-        runtime_environment.h
-        runtime_interpreter.c
+    ../hooks/environment.c
+    apprun.cpp
 )
 
 target_compile_definitions(apprun_objects PRIVATE "$<$<CONFIG:Debug>:DEBUG>")
 target_include_directories(apprun_objects PUBLIC $<TARGET_PROPERTY:common_objects,INCLUDE_DIRECTORIES>)
 
 add_executable(
-        AppRun
-        main.c
-        $<TARGET_OBJECTS:apprun_objects>
-        $<TARGET_OBJECTS:common_objects>
+    AppRun
+    main.cpp
+    $<TARGET_OBJECTS:apprun_objects>
+    $<TARGET_OBJECTS:common_objects>
 )
 
 target_compile_definitions(AppRun PRIVATE "$<$<CONFIG:Debug>:DEBUG>")
 target_include_directories(AppRun PRIVATE $<TARGET_PROPERTY:common_objects,INCLUDE_DIRECTORIES>)
+target_link_libraries(AppRun PRIVATE libconfig++ -static)
 install(
-        TARGETS AppRun
-        RUNTIME DESTINATION bin
+    TARGETS AppRun
+    RUNTIME DESTINATION bin
 )
 add_dependencies(AppRun apprun_hooks)