dash/contrib/macdeploy

MacOS Deployment

The macdeployqtplus script should not be run manually. Instead, after building as usual:

make deploy

When complete, it will have produced Dash-Qt.dmg.

SDK Extraction

Step 1: Obtaining Xcode.app

A free Apple Developer Account is required to proceed.

Our macOS SDK can be extracted from Xcode_15.xip.

Alternatively, after logging in to your account go to 'Downloads', then 'More' and search for Xcode 15.

An Apple ID and cookies enabled for the hostname are needed to download this.

The sha256sum of the downloaded XIP archive should be 4daaed2ef2253c9661779fa40bfff50655dc7ec45801aba5a39653e7bcdde48e.

To extract the .xip on Linux:

# Install/clone tools needed for extracting Xcode.app
apt install cpio
git clone https://github.com/bitcoin-core/apple-sdk-tools.git

# Unpack the .xip and place the resulting Xcode.app in your current
# working directory
python3 apple-sdk-tools/extract_xcode.py -f Xcode_15.xip | cpio -d -i

On macOS:

xip -x Xcode_15.xip

Step 2: Generating the SDK tarball from Xcode.app

To generate the SDK, run the script gen-sdk with the path to Xcode.app (extracted in the previous stage) as the first argument.

./contrib/macdeploy/gen-sdk '/path/to/Xcode.app'

The generated archive should be: Xcode-15.0-15A240d-extracted-SDK-with-libcxx-headers.tar.gz. The sha256sum should be c0c2e7bb92c1fee0c4e9f3a485e4530786732d6c6dd9e9f418c282aa6892f55d.

Deterministic macOS DMG Notes

Working macOS DMGs are created in Linux by combining a recent clang, the Apple binutils (ld, ar, etc) and DMG authoring tools.

Apple uses clang extensively for development and has upstreamed the necessary functionality so that a vanilla clang can take advantage. It supports the use of -F, -target, -mmacosx-version-min, and -isysroot, which are all necessary when building for macOS.

Apple's version of binutils (called cctools) contains lots of functionality missing in the FSF's binutils. In addition to extra linker options for frameworks and sysroots, several other tools are needed as well. These do not build under Linux, so they have been patched to do so. The work here was used as a starting point: mingwandroid/toolchain4.

In order to build a working toolchain, the following source packages are needed from Apple: cctools, dyld, and ld64.

These tools inject timestamps by default, which produce non-deterministic binaries. The ZERO_AR_DATE environment variable is used to disable that.

This version of cctools has been patched to use the current version of clang's headers and its libLTO.so rather than those from llvmgcc, as it was originally done in toolchain4.

To complicate things further, all builds must target an Apple SDK. These SDKs are free to download, but not redistributable. See the SDK Extraction notes above for how to obtain it.

The Guix process builds 2 sets of files: Linux tools, then Apple binaries which are created using these tools. The build process has been designed to avoid including the SDK's files in Guix's outputs. All interim tarballs are fully deterministic and may be freely redistributed.

xorrisofs is used to create the DMG.

A background image is added to DMG files by inserting a .DS_Store during creation.

As of OS X 10.9 Mavericks, using an Apple-blessed key to sign binaries is a requirement in order to satisfy the new Gatekeeper requirements. Because this private key cannot be shared, we'll have to be a bit creative in order for the build process to remain somewhat deterministic. Here's how it works:

• Builders use Guix to create an unsigned release. This outputs an unsigned DMG which users may choose to bless and run. It also outputs an unsigned app structure in the form of a tarball, which also contains all of the tools that have been previously (deterministically) built in order to create a final DMG.

• The Apple keyholder uses this unsigned app to create a detached signature, using the script that is also included there. Detached signatures are available from this repository.

• Builders feed the unsigned app + detached signature back into Guix. It uses the pre-built tools to recombine the pieces into a deterministic DMG.