build: use macOS 10.14 SDK

Co-Authored-By: Carl Dong <accounts@carldong.me>

1 files changed, 128 insertions, 8 deletions

diff --git a/contrib/macdeploy/README.md b/contrib/macdeploy/README.md
index 29b49ebff4..f78bebf114 100644
--- a/contrib/macdeploy/README.md
+++ b/contrib/macdeploy/README.md
@@ -1,15 +1,135 @@
-### MacDeploy ###
+# MacOS Deployment
 
-For Snow Leopard (which uses [Python 2.6](http://www.python.org/download/releases/2.6/)), you will need the param_parser package:
+The `macdeployqtplus` script should not be run manually. Instead, after building as usual:
 
-	sudo easy_install argparse
+```bash
+make deploy
+```
 
-This script should not be run manually, instead, after building as usual:
+During the deployment process, the disk image window will pop up briefly
+when the fancy settings are applied. This is normal, please do not interfere,
+the process will unmount the DMG and cleanup before finishing.
 
-	make deploy
+When complete, it will have produced `Bitcoin-Qt.dmg`.
 
-During the process, the disk image window will pop up briefly where the fancy
-settings are applied. This is normal, please do not interfere.
+## SDK Extraction
 
-When finished, it will produce `Bitcoin-Qt.dmg`.
+`Xcode.app` is packaged in a `.xip` archive.
+This makes the SDK less-trivial to extract on non-macOS machines.
+One approach (tested on Debian Buster) is outlined below:
 
+```bash
+
+apt install clang cpio git liblzma-dev libxml2-dev libssl-dev make
+
+git clone https://github.com/tpoechtrager/xar
+pushd xar/xar
+./configure
+make
+make install
+popd
+
+git clone https://github.com/NiklasRosenstein/pbzx
+pushd pbzx
+clang -llzma -lxar pbzx.c -o pbzx -Wl,-rpath=/usr/local/lib
+popd
+
+xar -xf Xcode_10.2.1.xip -C .
+
+./pbzx/pbzx -n Content | cpio -i
+
+find Xcode.app -type d -name MacOSX.sdk -execdir sh -c 'tar -c MacOSX.sdk/ | gzip -9n > /MacOSX10.14.sdk.tar.gz' \;
+```
+
+on macOS the process is more straightforward:
+
+```bash
+xip -x Xcode_10.2.1.xip
+tar -C Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/ -czf MacOSX10.14.sdk.tar.gz MacOSX.sdk
+```
+
+Our previously used macOS SDK (`MacOSX10.11.sdk`) can be extracted from
+[Xcode 7.3.1 dmg](https://developer.apple.com/devcenter/download.action?path=/Developer_Tools/Xcode_7.3.1/Xcode_7.3.1.dmg).
+The script [`extract-osx-sdk.sh`](./extract-osx-sdk.sh) automates this. First
+ensure the DMG file is in the current directory, and then run the script. You
+may wish to delete the `intermediate 5.hfs` file and `MacOSX10.11.sdk` (the
+directory) when you've confirmed the extraction succeeded.
+
+```bash
+apt-get install p7zip-full sleuthkit
+contrib/macdeploy/extract-osx-sdk.sh
+rm -rf 5.hfs MacOSX10.11.sdk
+```
+
+## 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 `--sysroot`, 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 such as `install_name_tool`, `lipo`, and `nmedit`. 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](https://github.com/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. To obtain it, register for an Apple Developer Account,
+then download [Xcode 10.2.1](https://download.developer.apple.com/Developer_Tools/Xcode_10.2.1/Xcode_10.2.1.xip).
+
+This file is many gigabytes in size, but most (but not all) of what we need is
+contained only in a single directory:
+
+```bash
+Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.14.sdk
+```
+
+See the SDK Extraction notes above for how to obtain it.
+
+The Gitian descriptors build 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 Gitian's outputs. All interim tarballs are fully deterministic and may be freely
+redistributed.
+
+`genisoimage` is used to create the initial DMG. It is not deterministic as-is, so it has been
+patched. A system `genisoimage` will work fine, but it will not be deterministic because
+the file-order will change between invocations. The patch can be seen here: [cdrkit-deterministic.patch](https://github.com/bitcoin/bitcoin/blob/master/depends/patches/native_cdrkit/cdrkit-deterministic.patch).
+No effort was made to fix this cleanly, so it likely leaks memory badly, however it's only used for
+a single invocation, so that's no real concern.
+
+`genisoimage` cannot compress DMGs, so afterwards, the DMG tool from the
+`libdmg-hfsplus` project is used to compress it. There are several bugs in this tool and its
+maintainer has seemingly abandoned the project.
+
+The DMG tool has the ability to create DMGs from scratch as well, but this functionality is
+broken. Only the compression feature is currently used. Ideally, the creation could be fixed
+and `genisoimage` would no longer be necessary.
+
+Background images and other features can be added to DMG files by inserting a
+`.DS_Store` before creation. This is generated by the script `contrib/macdeploy/custom_dsstore.py`.
+
+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 Gitian 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](https://github.com/bitcoin-core/bitcoin-detached-sigs).
+- Builders feed the unsigned app + detached signature back into Gitian. It uses the
+  pre-built tools to recombine the pieces into a deterministic DMG.