Log last 1000 lines of tmux output in bootlog (#2149)

* log last 1000 lines of tmux output in bootlog

* add to bootlog

* fix tmux capture
old-commit-hash: 6b4957cba10985507c5ba2337ee08b6392f86ddb

launch_chffrplus.sh

@@ -113,6 +113,9 @@ function launch {
   ln -sfn $(pwd) /data/pythonpath
   export PYTHONPATH="$PWD"
 
+  # write tmux scrollback to a file
+  tmux capture-pane -pq -S-1000 > /tmp/launch_log
+
   # start manager
   cd selfdrive
   ./manager.py

selfdrive/loggerd/loggerd.cc

@@ -593,6 +593,9 @@ static void bootlog() {
     std::string lastPmsg = util::read_file("/sys/fs/pstore/pmsg-ramoops-0");
     boot.setLastPmsg(capnp::Data::Reader((const kj::byte*)lastPmsg.data(), lastPmsg.size()));
 
+    std::string launchLog = util::read_file("/tmp/launch_log");
+    boot.setLaunchLog(capnp::Text::Reader(launchLog.data(), launchLog.size()));
+
     auto bytes = msg.toBytes();
     logger_log(&s.logger, bytes.begin(), bytes.size(), false);
   }