12 KiB
Developing Crashpad
Status
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Introduction
Crashpad is a Chromium project. Most of its development practices follow Chromium’s. In order to function on its own in other projects, Crashpad uses mini_chromium, a small, self-contained library that provides many of Chromium’s useful low-level base routines. mini_chromium’s README provides more detail.
Prerequisites
To develop Crashpad, the following tools are necessary, and must be present in
the $PATH
environment variable:
- Appropriate development tools.
- On macOS, install Xcode. The latest version is generally recommended.
- On Windows, install Visual Studio with C++ support and the Windows SDK. The latest version is generally recommended. Some tests also require the CDB debugger, installed with Debugging Tools for Windows.
- On Linux, obtain appropriate tools for C++ development through any
appropriate means including the system’s package manager. On Debian and
Debian-based distributions, the
build-essential
andzlib1g-dev
packages should suffice.
- Chromium’s depot_tools.
- Git. This is provided by Xcode on macOS, by depot_tools on Windows, and through any appropriate means including the system’s package manager on Linux.
- Python. This is provided by the operating system on macOS, by depot_tools on Windows, and through any appropriate means including the system’s package manager on Linux.
Getting the Source Code
The main source code repository is a Git repository hosted at
https://chromium.googlesource.com/crashpad/crashpad. Although it is possible to
check out this repository directly with git clone
, Crashpad’s dependencies are
managed by
gclient
instead of Git submodules, so to work on Crashpad, it is best to use fetch
to
get the source code.
fetch
and gclient
are part of the
depot_tools. There’s
no need to install them separately.
Initial Checkout
$ mkdir ~/crashpad
$ cd ~/crashpad
$ fetch crashpad
fetch crashpad
performs the initial git clone
and gclient sync
,
establishing a fully-functional local checkout.
Subsequent Checkouts
$ cd ~/crashpad/crashpad
$ git pull -r
$ gclient sync
Building
Windows, Mac, Linux, Fuchsia
On Windows, Mac, Linux, and Fuchsia, Crashpad uses GN to generate Ninja build files. For example,
$ cd ~/crashpad/crashpad
$ gn gen out/Default
$ ninja -C out/Default
You can then use gn args out/Default
or edit out/Default/args.gn
to
configure the build, for example things like is_debug=true
or
target_cpu="x86"
.
GN and Ninja are part of the depot_tools. There’s no need to install them separately.
Fuchsia
In order to instruct gclient to download the Fuchsia SDK, you need to add the
following to ~/crashpad/.gclient
:
target_os=["fuchsia"]
If you're using this tree to develop for multiple targets, you can also add
other entries to the the list (e.g. target_os=["fuchsia", "mac"]
).
Optional Linux Configs
To pull and use Crashpad's version of clang and sysroot, make the following changes.
Add the following to ~/crashpad/.gclient
.
"custom_vars": { "pull_linux_clang": True },
Add these args to out/Default/args.gn
.
clang_path = "//third_party/linux/clang/linux-amd64"
target_sysroot = "//third_party/linux/sysroot"
Android
This build relies on cross-compilation. It’s possible to develop Crashpad for Android on any platform that the Android NDK (Native Development Kit) runs on.
If it’s not already present on your system, download the NDK package for your
system and expand it to a
suitable location. These instructions assume that it’s been expanded to
~/android-ndk-r21b
.
Note that Chrome uses Android API level 21 for both 64-bit platforms and
32-bit platforms. See Chrome’s
build/config/android/config.gni
which sets android32_ndk_api_level
and android64_ndk_api_level
.
Set these gn args
target_os = "android"
android_ndk_root = ~/android-ndk-r21b
android_api_level = 21
Testing
Crashpad uses Google Test as its
unit-testing framework, and some tests use Google
Mock as well. Its
tests are currently split up into several test executables, each dedicated to
testing a different component. This may change in the future. After a successful
build, the test executables will be found at out/Debug/crashpad_*_test
.
$ cd ~/crashpad/crashpad
$ out/Debug/crashpad_minidump_test
$ out/Debug/crashpad_util_test
A script is provided to run all of Crashpad’s tests. It accepts a single argument, a path to the directory containing the test executables.
$ cd ~/crashpad/crashpad
$ python build/run_tests.py out/Debug
To run a subset of the tests, use the --gtest_filter
flag, e.g., to run all
the tests for MinidumpStringWriter:
$ python build/run_tests.py out/Debug --gtest_filter MinidumpStringWriter\*
Windows
On Windows, end_to_end_test.py
requires the CDB debugger, installed with
Debugging Tools for
Windows. This
can be installed either as part of the Windows Driver
Kit or
the Windows
SDK. If the
Windows SDK has already been installed (possibly with Visual Studio) but
Debugging Tools for Windows is not present, it can be installed from Add or
remove programs→Windows Software Development Kit.
Android
To test on Android, ADB (Android Debug
Bridge) from the
Android SDK must be in the PATH
. Note
that it is sufficient to install just the command-line tools from the Android
SDK. The entire Android Studio IDE is not necessary to obtain ADB.
When asked to test an Android build directory, run_tests.py
will detect a
single connected Android device (including an emulator). If multiple devices are
connected, one may be chosen explicitly with the ANDROID_DEVICE
environment
variable. run_tests.py
will upload test executables and data to a temporary
location on the detected or selected device, run them, and clean up after itself
when done.
Fuchsia
To test on Fuchsia, you need a connected device running Fuchsia. Run:
$ gn gen out/fuchsia --args 'target_os="fuchsia" target_cpu="x64" is_debug=true'
$ ninja -C out/fuchsia
$ python build/run_tests.py out/fuchsia
If you have multiple devices running, you will need to specify which device you want using their hostname, for instance:
$ ZIRCON_NODENAME=scare-brook-skip-dried python build/run_tests.py out/fuchsia
Contributing
Crashpad’s contribution process is very similar to Chromium’s contribution process.
Code Review
A code review must be conducted for every change to Crashpad’s source code. Code
review is conducted on Chromium’s
Gerrit system, and all code reviews
must be sent to an appropriate reviewer, with a Cc sent to
crashpad-dev. The
codereview.settings
file specifies this environment to git-cl
.
git-cl
is part of the
depot_tools. There’s
no need to install it separately.
$ cd ~/crashpad/crashpad
$ git checkout -b work_branch origin/master
…do some work…
$ git add …
$ git commit
$ git cl upload
Uploading a patch to Gerrit does not automatically request a review. You must
select a reviewer on the Gerrit review page after running git cl upload
. This
action notifies your reviewer of the code review request. If you have lost track
of the review page, git cl issue
will remind you of its URL. Alternatively,
you can request review when uploading to Gerrit by using git cl upload --send-mail
.
Git branches maintain their association with Gerrit reviews, so if you need to
make changes based on review feedback, you can do so on the correct Git branch,
committing your changes locally with git commit
. You can then upload a new
patch set with git cl upload
and let your reviewer know you’ve addressed the
feedback.
The most recently uploaded patch set on a review may be tested on a
trybot
by running git cl try
or by clicking the “CQ Dry Run” button in Gerrit. These
set the “Commit-Queue: +1” label. This does not mean that the patch will be
committed, but the trybot and commit queue share infrastructure and a Gerrit
label. The patch will be tested on trybots in a variety of configurations.
Status information will be available on Gerrit. Trybot access is available to
Crashpad and Chromium committers.
Landing Changes
After code review is complete and “Code-Review: +1” has been received from all reviewers, the patch can be submitted to Crashpad’s commit queue by clicking the “Submit to CQ” button in Gerrit. This sets the “Commit-Queue: +2” label, which tests the patch on trybots before landing it. Commit queue access is available to Crashpad and Chromium committers.
Although the commit queue is recommended, if needed, project members can bypass
the commit queue and land patches without testing by using the “Submit” button
in Gerrit or by committing via git cl land
:
$ cd ~/crashpad/crashpad
$ git checkout work_branch
$ git cl land
External Contributions
Copyright holders must complete the Individual Contributor License
Agreement or
Corporate Contributor License
Agreement as
appropriate before any submission can be accepted, and must be listed in the
AUTHORS
file. Contributors may be listed in the
CONTRIBUTORS
file.
Buildbot
The Crashpad Buildbot performs automated builds and tests of Crashpad. Before checking out or updating the Crashpad source code, and after checking in a new change, it is prudent to check the Buildbot to ensure that “the tree is green.”