feature: add building with pem-pack

[Vollstrecker]

fixes: #97

As requested here the option to compile with pem. There are no test for it as the scripts show it relies on openssh and other external progs to generate test-input.

[karaca75]

@Vollstrecker thanks for the future. I am new to cpp. How should I include the pem.h? When I use #include <cryptopp/pem.h> I am getting this error in visual studio (generated from cmakelist) : can not open source files. Thanks for the help.

CMakeLists.txt content

cmake_minimum_required(VERSION 3.28)
project(CryptoDemo)
set(LIBRARY_NAME CryptoDemoLIB)
set(EXE_NAME CryptoDemo)
add_library(${LIBRARY_NAME} STATIC src/CryptoService.h src/CryptoService.cpp)

include(FetchContent)

message(CHECK_START "Fetching CryptoPP-CMAKE")

set(CRYPTOPP_CMAKE "cryptopp-cmake")
option(CRYPTOPP_USE_PEM_PACK "ON" "ON")
option(CRYPTOPP_BUILD_TESTING "OFF" "OFF")
set(CRYPTOPP_GIT_TAG "master")
 
FetchContent_Declare(
        ${CRYPTOPP_CMAKE}
        GIT_REPOSITORY  https://github.com/abdes/cryptopp-cmake.git
        GIT_TAG         ${CRYPTOPP_GIT_TAG}
)

FetchContent_MakeAvailable(${CRYPTOPP_CMAKE})
target_link_libraries(${LIBRARY_NAME} PRIVATE cryptopp::cryptopp)

add_executable(${EXE_NAME} src/main.cpp)
target_link_libraries(${EXE_NAME} PRIVATE ${LIBRARY_NAME})

[Vollstrecker]

Looks like your chainbuilding. If you always do it like that, you could use a define instead of cryptopp/ and set it to "${cryptopp-pem_SOURCE_DIR}/". Or you install cryptopp as the headers should be installed with it. But I see no pem.h in the list, just pem_common.h and (without checking) I'm sure that means this file does not exist at all.

[karaca75]

thanks for the answer but as I am new to cpp could not understand what should I do? Can you help me with an updated CmakeLists.txt please? Thanks!

this is what I have currently:

cmake_minimum_required(VERSION 3.28)
project(CryptoDemo)
set(LIBRARY_NAME CryptoDemoLIB)
set(EXE_NAME CryptoDemo)
add_library(${LIBRARY_NAME} STATIC src/CryptoService.h src/CryptoService.cpp)

include(FetchContent)

message(CHECK_START "Fetching CryptoPP-CMAKE")

set(CRYPTOPP_CMAKE "cryptopp-cmake")
option(CRYPTOPP_USE_PEM_PACK "ON" "ON")
option(CRYPTOPP_BUILD_TESTING "OFF" "OFF")
set(CRYPTOPP_GIT_TAG "master")
 
FetchContent_Declare(
        ${CRYPTOPP_CMAKE}
        GIT_REPOSITORY  https://github.com/abdes/cryptopp-cmake.git
        GIT_TAG         ${CRYPTOPP_GIT_TAG}
)

FetchContent_MakeAvailable(${CRYPTOPP_CMAKE})
target_link_libraries(${LIBRARY_NAME} PRIVATE cryptopp::cryptopp)

add_executable(${EXE_NAME} src/main.cpp)
target_link_libraries(${EXE_NAME} PRIVATE ${LIBRARY_NAME})

[Vollstrecker]

Now I checked and add pem.h.

You need something like

'target_compile_definitions(foo PRIVATE PEM_PATH="${cryptopp-pem_SOURCE_DIR}")

and your your source your replace cryptopp with PEM_PATH. If you start detecting an installed cryptopp you guard that with #if not defined and set it to cryptopp.

[karaca75]

thanks @Vollstrecker I tried the new master but getting this error during cmake configure

-- Configuring done (39.8s)
CMake Error at out/_deps/cryptopp-cmake-src/cryptopp/CMakeLists.txt:1376 (add_library):
  Cannot find source file:

    /out/_deps/cryptopp-pem-src/pem.cpp


CMake Error at out/_deps/cryptopp-cmake-src/cryptopp/CMakeLists.txt:1376 (add_library):
  No SOURCES given to target: cryptopp

[Vollstrecker]

This happens when you something fast online. Should be fixed now

[karaca75]

update: all working thanks @Vollstrecker

thank you @Vollstrecker but still I could not make it work. Even if I manually add pem.h it is giving error: PEM_Load and PEM_Save is undefined. I don't know what I am missing here

[Vollstrecker]

To be honest, beside the tip "don'hardcode that path" I can only tell you to find out what's happening. The docs tell us just to compile the files into the lib and that's what has been done.