neobytes/doc/README_osx.txt
Wladimir J. van der Laan e7a6f79e5a Merge #7192: Unify product name to as few places as possible
027fdb8 When/if the copyright line does not mention Bitcoin Core developers, add a second line to copyrights in -version, About dialog, and splash screen (Luke Dashjr)
cc2095e Rewrite FormatParagraph to handle newlines within input strings correctly (Luke Dashjr)
cddffaf Bugfix: Include COPYRIGHT_HOLDERS_SUBSTITUTION in Makefile substitutions so it gets passed to extract-strings correctly (Luke Dashjr)
29598e4 Move PACKAGE_URL to configure.ac (Luke Dashjr)
78ec83d splashscreen: Resize text to fit exactly (Luke Dashjr)
3cae140 Bugfix: Actually use _COPYRIGHT_HOLDERS_SUBSTITUTION everywhere (Luke Dashjr)
4d5a3df Bugfix: gitian-descriptors: Add missing python-setuptools requirement for OS X (biplist module) (Luke Dashjr)
e4ab5e5 Bugfix: Correct copyright year in Mac DMG background image (Luke Dashjr)
917b1d0 Set copyright holders displayed in notices separately from the package name (Luke Dashjr)
c39a6ff Travis & gitian-osx: Use depends for ds_store and mac_alias modules (Luke Dashjr)
902ccde depends: Add mac_alias to depends (Luke Dashjr)
82a2d98 depends: Add ds_store to depends (Cory Fields)
de619a3 depends: Pass PYTHONPATH along to configure (Cory Fields)
e611b6e macdeploy: Use rsvg-convert rather than cairosvg (Luke Dashjr)
63bcdc5 More complicated package name substitution for Mac deployment (Luke Dashjr)
1a6c67c Parameterise 2009 in translatable copyright strings (Luke Dashjr)
d5f4683 Unify package name to as few places as possible without major changes (Luke Dashjr)
2017-12-11 08:30:26 +01:00

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Deterministic OS X Dmg Notes.
Working OS X DMGs are created in Linux by combining a recent clang,
the Apple's 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 OS X. A pre-compiled version of 3.2 is used because it was not
available in the Precise repositories at the time this work was started. In the
future, it can be switched to use system packages instead.
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:
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 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 a developer account, then download the Xcode 6.1.1 dmg:
https://developer.apple.com/devcenter/download.action?path=/Developer_Tools/xcode_6.1.1/xcode_6.1.1.dmg
This file is several gigabytes in size, but only a single directory inside is
needed: Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk
Unfortunately, the usual linux tools (7zip, hpmount, loopback mount) are incapable of opening this file.
To create a tarball suitable for Gitian input, mount the dmg in OS X, then create it with:
$ tar -C /Volumes/Xcode/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/ -czf MacOSX10.9.sdk.tar.gz MacOSX10.9.sdk
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:
https://raw.githubusercontent.com/theuni/osx-cross-depends/master/patches/cdrtools/genisoimage.diff
No effort was made to fix this cleanly, so it likely leaks memory badly. But
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. It has been forked
and is available (with fixes) here: https://github.com/theuni/libdmg-hfsplus .
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 Mavericks (10.9), 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.
- Builders feed the unsigned app + detached signature back into Gitian. It
uses the pre-built tools to recombine the pieces into a deterministic dmg.