This adds a runtime exception helper (& test module) for Windows and
plumbing to allow the module to be registered by the crashpad client,
and to trigger the crashpad handler. Embedders can build their own
module to control which exceptions are passed to the handler.
See: go/chrome-windows-runtime-exception-helper for motivation.
When registered (which is the responsibility of the embedding
application), the helper is loaded by WerFault.exe when Windows
Error Reporting receives crashes that are not caught by crashpad's
normal handlers - for instance a control-flow violation when a
module is compiled with /guard:cf.
Registration:
The embedder must arrange for the full path to the helper to
be added in the appropriate Windows Error Reporting\
RuntimeExceptionHelperModules registry key.
Once an embedder's crashpad client is connected to a crashpad
handler (e.g. through SetIpcPipeName()) the embedder calls
RegisterWerModule. Internally, this registration includes handles
used to trigger the crashpad handler, an area reserved to hold an
exception and context, and structures needed by the crashpad handler.
Following a crash:
WerFault.exe handles the crash then validates and loads the helper
module. WER hands the helper module a handle to the crashing target
process and copies of the exception and context for the faulting thread.
The helper then copies out the client's registration data and
duplicates handles to the crashpad handler, then fills back the various structures in the paused client that the crashpad handler will need.
The helper then signals the crashpad handler, which collects a dump then
notifies the helper that it is done.
Support:
WerRegisterExceptionHelperModule has been availble since at least
Windows 7 but WerFault would not pass on the exceptions that crashpad
could not already handle. This changed in Windows 10 20H1 (19041),
which supports HKCU and HKLM registrations, and passes in more types of
crashes. It is harmless to register the module for earlier versions
of Windows as it simply won't be loaded by WerFault.exe.
Tests:
snapshot/win/end_to_end_test.py has been refactored slightly to
group crash generation and output validation in main() by breaking
up RunTests into smaller functions.
As the module works by being loaded in WerFault.exe it is tested
in end_to_end_test.py.
Bug: crashpad:133, 866033, 865632
Change-Id: Id668bd15a510a24c79753e1bb03e9456f41a9780
Reviewed-on: https://chromium-review.googlesource.com/c/crashpad/crashpad/+/3677284
Reviewed-by: Joshua Peraza <jperaza@chromium.org>
Commit-Queue: Alex Gough <ajgo@chromium.org>
