openssl-cmake

Build OpenSSL in parallel within CMake

Features

• Support OpenSSL versions from 1.1.1 to the latest 3.5.x
• Detect the target platform (Linux, macOS, Windows, Android, iOS, and more)
• Download the source code only once (thanks CPM.cmake!)
• Don't reconfigure if same options are used
• Automatically use the maximum number of processors
• Reduce rebuild time using ccache
• Override the FindOpenSSL CMake module (no need to change existing CMake code)

CMake Options

Option	Type	Default	Description
OPENSSL_BUILD_OPTIONS	list	(undefined)	make-compatible options
OPENSSL_BUILD_TARGET	string	build_libs	Makefile target for build
OPENSSL_BUILD_VERBOSE	bool	OFF	Enable verbose output from build
OPENSSL_CONFIGURE_OPTIONS	list	(undefined)	Use OpenSSL's Configure options
OPENSSL_CONFIGURE_VERBOSE	bool	OFF	Enable verbose output from configuration
OPENSSL_ENABLE_PARALLEL	bool	ON	Build and test in parallel if possible
OPENSSL_INSTALL	bool	OFF	Install OpenSSL components
OPENSSL_INSTALL_CERT	bool	OFF	Install cert.pem to the openssldir directory
OPENSSL_INSTALL_TARGET	string	install_dev	Makefile target for install
OPENSSL_PATCH	list	(undefined)	Apply patches to OpenSSL source
OPENSSL_SOURCE	path	(undefined)	Specify the location of OpenSSL source (URL or path)
OPENSSL_TARGET_PLATFORM	string	(undefined)	Use OpenSSL's Configure target (see below)
OPENSSL_TARGET_VERSION	string	3.5.x	Use the latest OpenSSL version by default
OPENSSL_TEST	bool	OFF	Enable testing and build OpenSSL self tests
OPENSSL_USE_CCACHE	bool	ON	Use ccache if available

Important

• OPENSSL_PATCH
  • Since OpenSSL source is distributed with LF, patch files also should be LF
• OPENSSL_USE_CCACHE
  • Whenever you change this option, perform a fresh configuration (or just delete CMakeCache.txt)
  • This option will remove /Zi /Fd on MSVC

Note

• OPENSSL_CONFIGURE_OPTIONS
  • no-shared is added when BUILD_SHARED_LIBS is OFF
  • no-tests is added when OPENSSL_TEST is OFF
• OPENSSL_TARGET_PLATFORM
  • If this option is empty, the target platform will be detected
  • If openssl-cmake fails to detect, you need to set this option explicitly

Tip

• OPENSSL_INSTALL
  • To change the installation path, add --prefix=<path> to OPENSSL_CONFIGURE_OPTIONS
• OPENSSL_INSTALL_CERT
  • The CA certs will be downloaded from https://curl.se/docs/caextract.html
• OPENSSL_SOURCE
  • You can download OpenSSL source from the internet or use the local OpenSSL source
  • If this option is empty or invalid, OpenSSL source will be downloaded from the official website

Prerequisites

Requirements

• CMake 3.25+
• OpenSSL build tools Link
  • Make implementation
  • Perl 5
  • ANSI C compiler
  • NASM (Windows only)
• ccache (optional)

Linux

Install CMake from official website or Snapcraft

# Debian
sudo snap install cmake --classic
sudo apt-get install -y build-essential perl ninja-build ccache

macOS

Install packages from Homebrew

brew install cmake perl ninja ccache
xcode-select --install

Windows

Install packages from Chocolatey

# Powershell (run as administrator)
choco install -y cmake jom strawberryperl nasm ccache --installargs 'ADD_CMAKE_TO_PATH=System'

# Append "C:\Program Files\NASM" to the PATH environment variable
# or run this code
[Environment]::SetEnvironmentVariable("PATH", "$ENV:PATH;C:\Program Files\NASM", "USER")

Usage

Build

cmake --list-presets all                    # List all CMake presets
cmake --preset windows                      # Configure
cmake --build --preset windows              # Build
ctest --preset windows                      # Test
cmake --build --preset windows -t install   # Install

Integration

FetchContent_Declare(
    openssl-cmake
    URL https://github.com/jimmy-park/openssl-cmake/archive/main.tar.gz
)
FetchContent_MakeAvailable(openssl-cmake)

add_executable(main main.cpp)
target_link_libraries(main PRIVATE
    OpenSSL::SSL
    OpenSSL::Crypto
    OpenSSL::applink
)

Important

• FetchContent_MakeAvailable(openssl-cmake) must be preceded before find_package(OpenSSL)
• If some libraries link OpenSSL using OPENSSL_LIBRARIES variable rather than OpenSSL::SSL target, add_dependencies() may help change the build order

Using CPM.cmake

CPMAddPackage(
    NAME openssl-cmake
    URL https://github.com/jimmy-park/openssl-cmake/archive/main.tar.gz
    OPTIONS
    "OPENSSL_CONFIGURE_OPTIONS option1\\\\;option2"
)

Tip

For some reason, CPM requires double-escaping for semicolon-separated lists.

Benchmarks

Configuration	Time	Speed
Sequential	168 s	1.00 x
Sequential w/ ccache (cold)	460 s	0.37 x
Sequential w/ ccache (warm)	111 s	1.51 x
Parallel	34 s	4.94 x
Parallel w/ ccache (cold)	78 s	2.15 x
Parallel w/ ccache (warm)	21 s	8.00 x

• OS : Windows 10 22H2
• CPU : AMD Ryzen 5 3600 6-Core Processor 3.60 GHz
• RAM : 16 GB
• Storage : Samsung SSD 860 EVO
• Compiler : MSVC 19.36
• Configuration
  • OpenSSL 3.1.1 (VC-WIN64A, no-tests, no-asm, no-makedepend, no-shared)
  • ccache 4.8.1 (default options)

Tip

There are benchmark workflows