bluetooth embedded-linux android-bluetooth ninja gn

Compiling fluoride bluetooth stack for embedded linux

Has anyone been able to compile fluoride bluetooth stack separately for an embedded linux device?
There is a guide at https://android.googlesource.com/platform/system/bt/+/181144a50114c824cfe3cdfd695c11a074673a5e/README.md, but following these instructions gn gen fails without getting the common-mk folder and modding some build files so there are no missing variables, folders etc.

I have been able to generate Ninja files, but when building, there are missing gtest and modp_b64 headers. After getting them from Google's source search, Ninja seems to be able to run a bit without errors, but ultimately fails with:

In file included from ../../third_party/libchrome/base/message_loop/message_loop.h:18:
../../third_party/libchrome/base/message_loop/message_loop_current.h:209:3: error: static_assert failed due to requirement 'std::is_same<MessagePumpForUI, MessagePumpLibevent>::value' "MessageLoopCurrentForUI::WatchFileDescriptor is not supported when MessagePumpForUI is not a MessagePumpLibevent."
  static_assert(std::is_same<MessagePumpForUI, MessagePumpLibevent>::value,
  ^             ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../../third_party/libchrome/base/message_loop/message_loop_current.h:214:28: error: no type named 'Mode' in 'base::MessagePumpGlib'; did you mean 'MessagePumpLibevent::Mode'?
                           MessagePumpForUI::Mode mode,
                           ^~~~~~~~~~~~~~~~~~~~~~
                           MessagePumpLibevent::Mode
../../third_party/libchrome/base/message_loop/watchable_io_message_pump_posix.h:55:8: note: 'MessagePumpLibevent::Mode' declared here
  enum Mode {
       ^
In file included from ../../third_party/libchrome/base/run_loop.cc:10:
In file included from ../../third_party/libchrome/base/message_loop/message_loop.h:18:
../../third_party/libchrome/base/message_loop/message_loop_current.h:215:28: error: no type named 'FdWatchController' in 'base::MessagePumpGlib'; did you mean 'MessagePumpLibevent::FdWatchController'?
                           MessagePumpForUI::FdWatchController* controller,
                           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
                           MessagePumpLibevent::FdWatchController
../../third_party/libchrome/base/message_loop/message_pump_libevent.h:28:9: note: 'MessagePumpLibevent::FdWatchController' declared here
  class FdWatchController : public FdWatchControllerInterface {
        ^
In file included from ../../third_party/libchrome/base/run_loop.cc:10:
In file included from ../../third_party/libchrome/base/message_loop/message_loop.h:18:
../../third_party/libchrome/base/message_loop/message_loop_current.h:216:28: error: no type named 'FdWatcher' in 'base::MessagePumpGlib'; did you mean 'MessagePumpLibevent::FdWatcher'?
                           MessagePumpForUI::FdWatcher* delegate);
                           ^~~~~~~~~~~~~~~~~~~~~~~~~~~
                           MessagePumpLibevent::FdWatcher
../../third_party/libchrome/base/message_loop/watchable_io_message_pump_posix.h:17:9: note: 'MessagePumpLibevent::FdWatcher' declared here
  class FdWatcher {
        ^
4 errors generated.

All the errors and missing files are coming from third_party/libchrome
Any help would be much appreciated.

Solution

I followed instructions at https://cs.android.com/android/platform/superproject/+/master:system/bt/README.md

In addition to instructions there, I had to resolve issues in the build script manually. I was able to compile the bluetooth stack successfully in Ubuntu 21.04

Replace //bt with /home/udara/fluoride/bt in build files.

Used sed command. Change to your fluoride directory as appropriate.

for file in $(grep -r -l "//bt"); do sed -i 's/\/\/bt/\/home\/udara\/fluoride\/bt/g' $file; done

Copied common-mk symlink generated by bootstrap.py to the fluoride directory.
And replaced //common-mk with /home/udara/fluoride/common-mk.

for file in $(grep -r -l "//common-mk"); do sed -i 's/\/\/common-mk/\/home\/udara\/fluoride\/common-mk/g' $file; done

Installed few missing dependencies

sudo apt install llvm
sudo apt install libc++abi-dev

Copied /home/udara/fluoride/bt/output/out/Default/gen/ABS_PATH/home/udara/fluoride/bt/gd/dumpsys/bundler/bundler_generated.h to /home/udara/fluoride/bt/gd/dumpsys/

cp /home/udara/fluoride/bt/output/out/Default/gen/ABS_PATH/home/udara/fluoride/bt/gd/dumpsys/bundler/bundler_generated.h /home/udara/fluoride/bt/gd/dumpsys/

Created directory named output in the bt directory.
Set environment variables

# this is set by bootstrap.py
export STAGING_DIR=/home/udara/fluoride/staging

# you have to manually set this
export OUTPUT_DIR=/home/udara/fluoride/bt/output

Then compile the bluetooth stack with

./build.py --output ${OUTPUT_DIR} --platform-dir ${STAGING_DIR} --clang

Add the following lines to /etc/dbus-1/system.d/bluetooth.conf

<policy>
    ...
    <allow own="org.chromium.bluetooth"/>
    <allow own="org.chromium.bluetooth.Manager"/>
</policy>

Finally run fluoride with

cd /home/udara/fluoride/bt/output/debug
sudo ./btadapterd --hci=0 INIT_gd_hci=true