How to run a daemon and collect ftrace from it. (The example is mm-qcamera-daemon)

qcamerasvr_wrapper.sh

#!/system/bin/sh

echo 'function_graph' >/sys/kernel/debug/tracing/current_tracer
echo 96000 > /d/tracing/buffer_size_kb
echo $$ > /sys/kernel/debug/tracing/set_ftrace_pid

echo 1 > /sys/kernel/debug/tracing/tracing_on

(
  sleep 10 # stop tracing after this second.
  echo 0 > /sys/kernel/debug/tracing/tracing_on
  cat /sys/kernel/debug/tracing/trace >/data/local/tmp/strace/qcamerasvr.ftrace
  echo 'nop' >/sys/kernel/debug/tracing/current_tracer
) &

exec /system/bin/mm-qcamera-daemon