selftests/ftrace: Add test to test new set_event_notrace_pid file

#!/bin/sh

# SPDX-License-Identifier: GPL-2.0

# description: event tracing - restricts events based on pid notrace filtering

# flags: instance

do_reset() {

    echo > set_event

    echo > set_event_pid

    echo > set_event_notrace_pid

    echo 0 > options/event-fork

    echo 0 > events/enable

    clear_trace

    echo 1 > tracing_on

}

fail() { #msg

    cat trace

    do_reset

    echo $1

    exit_fail

}

count_pid() {

    pid=$@

    cat trace | grep -v '^#' | sed -e 's/[^-]*-\([0-9]*\).*/\1/' | grep $pid | wc -l

}

count_no_pid() {

    pid=$1

    cat trace | grep -v '^#' | sed -e 's/[^-]*-\([0-9]*\).*/\1/' | grep -v $pid | wc -l

}

enable_system() {

    system=$1

    if [ -d events/$system ]; then

	echo 1 > events/$system/enable

    fi

}

enable_events() {

    echo 0 > tracing_on

    # Enable common groups of events, as all events can allow for

    # events to be traced via scheduling that we don't care to test.

    enable_system syscalls

    enable_system rcu

    enable_system block

    enable_system exceptions

    enable_system irq

    enable_system net

    enable_system power

    enable_system signal

    enable_system sock

    enable_system timer

    enable_system thermal

    echo 1 > tracing_on

}

if [ ! -f set_event -o ! -d events/sched ]; then

    echo "event tracing is not supported"

    exit_unsupported

fi

if [ ! -f set_event_pid -o ! -f set_event_notrace_pid ]; then

    echo "event pid notrace filtering is not supported"

    exit_unsupported

fi

echo 0 > options/event-fork

do_reset

read mypid rest < /proc/self/stat

echo $mypid > set_event_notrace_pid

grep -q $mypid set_event_notrace_pid

enable_events

yield

echo 0 > tracing_on

cnt=`count_pid $mypid`

if [ $cnt -ne 0 ]; then

    fail "Filtered out task has events"

fi

cnt=`count_no_pid $mypid`

if [ $cnt -eq 0 ]; then

    fail "No other events were recorded"

fi

do_reset

echo $mypid > set_event_notrace_pid

echo 1 > options/event-fork

enable_events

yield &

child=$!

echo "child = $child"

wait $child

echo 0 > tracing_on

cnt=`count_pid $mypid`

if [ $cnt -ne 0 ]; then

    fail "Filtered out task has events"

fi

cnt=`count_pid $child`

if [ $cnt -ne 0 ]; then

    fail "Child of filtered out taskhas events"

fi

cnt=`count_no_pid $mypid`

if [ $cnt -eq 0 ]; then

    fail "No other events were recorded"

fi

do_reset

exit 0