selftests: ftrace: Add a testcase for function PID filter

#!/bin/sh

# description: ftrace - function pid filters

# Make sure that function pid matching filter works.

# Also test it on an instance directory

if ! grep -q function available_tracers; then

    echo "no function tracer configured"

    exit_unsupported

fi

if [ ! -f set_ftrace_pid ]; then

    echo "set_ftrace_pid not found? Is function tracer not set?"

    exit_unsupported

fi

if [ ! -f set_ftrace_filter ]; then

    echo "set_ftrace_filter not found? Is function tracer not set?"

    exit_unsupported

fi

read PID _ < /proc/self/stat

# default value of function-fork option

orig_value=`grep function-fork trace_options`

do_reset() {

    reset_tracer

    clear_trace

    enable_tracing

    echo > set_ftrace_filter

    echo > set_ftrace_pid

    echo $orig_value > trace_options

}

fail() { # msg

    do_reset

    echo $1

    exit $FAIL

}

yield() {

    ping localhost -c 1 || sleep .001 || usleep 1 || sleep 1

}

do_test() {

    disable_tracing

    echo do_execve* > set_ftrace_filter

    echo *do_fork >> set_ftrace_filter

    echo $PID > set_ftrace_pid

    echo function > current_tracer

    # don't allow children to be traced

    echo nofunction-fork > trace_options

    enable_tracing

    yield

    count_pid=`cat trace | grep -v ^# | grep $PID | wc -l`

    count_other=`cat trace | grep -v ^# | grep -v $PID | wc -l`

    # count_other should be 0

    if [ $count_pid -eq 0 -o $count_other -ne 0 ]; then

	fail "PID filtering not working?"

    fi

    disable_tracing

    clear_trace

    # allow children to be traced

    echo function-fork > trace_options

    enable_tracing

    yield

    count_pid=`cat trace | grep -v ^# | grep $PID | wc -l`

    count_other=`cat trace | grep -v ^# | grep -v $PID | wc -l`

    # count_other should NOT be 0

    if [ $count_pid -eq 0 -o $count_other -eq 0 ]; then

	fail "PID filtering not following fork?"

    fi

}

do_test

mkdir instances/foo

cd instances/foo

do_test

cd ../../

rmdir instances/foo

do_reset

exit 0