#!/bin/bash
#
# The MIT License (MIT)
#
# Copyright (C) 2015 - Julien Desfossez <jdesfossez@efficios.com>
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.

# Helper to setup a local LTTng tracing session with the appropriate
# settings for the lttng analyses scripts

SESSION_NAME="lttng-analysis-$RANDOM"

destroy()
{
	lttng destroy $SESSION_NAME >/dev/null
	echo ""
	echo "You can now launch the analyses scripts on /$TRACEPATH"
	exit 0
}

if test "$1" = "-h" -o "$1" = "--help"; then
	echo "usage : $0"
	exit 0
fi

pgrep -u root lttng-sessiond >/dev/null
if test $? != 0; then
	echo "Starting lttng-sessiond as root (trying sudo, start manually if \
it fails)"
	sudo lttng-sessiond -d
	if test $? != 0; then
		exit 1
	fi
fi

SUDO=""
groups|grep tracing >/dev/null
if test $? != 0; then
	echo "You are not a member of the tracing group, so you need root \
access, the script will try with sudo"
	SUDO="sudo"
fi

# check if lttng command if in the path
# check if the user can execute the command (with sudo if not in tracing group)
# check if lttng-modules is installed
$SUDO lttng list -k | grep sched_switch >/dev/null
if test $? != 0; then
	echo "Something went wrong executing \"$SUDO lttng list -k | grep sched_switch\", \
try to fix the problem manually and then start the script again"
fi

# if our random session name was already in use, add more randomness...
$SUDO lttng list | grep $SESSION_NAME
if test $? = 0; then
	SESSION_NAME="$SESSION_NAME-$RANDOM"
fi
$SUDO lttng list | grep $SESSION_NAME
if test $? = 0; then
	echo "Cannot create a random session name, something must be wrong"
	exit 2
fi

lttng create $SESSION_NAME >/tmp/lttngout
[[ $? != 0 ]] && exit 2
TRACEPATH=$(grep Traces /tmp/lttngout | cut -d'/' -f2-)
rm /tmp/lttngout

trap "destroy" SIGINT SIGTERM

lttng enable-channel -k chan1 --subbuf-size=8M >/dev/null

# events that always work
lttng enable-event -s $SESSION_NAME -k sched_switch,sched_wakeup,sched_waking,block_rq_complete,block_rq_issue,block_bio_remap,block_bio_backmerge,netif_receive_skb,net_dev_xmit,sched_process_fork,sched_process_exec,lttng_statedump_process_state,lttng_statedump_file_descriptor,lttng_statedump_block_device,mm_vmscan_wakeup_kswapd,mm_page_free,mm_page_alloc,block_dirty_buffer,irq_handler_entry,irq_handler_exit,softirq_entry,softirq_exit,softirq_raise,kmem_mm_page_alloc,kmem_mm_page_free -c chan1 >/dev/null
[[ $? != 0 ]] && echo "Warning: some events were not enabled, some analyses might not be complete"

# events that might fail on specific kernels and that are not mandatory
lttng enable-event -s $SESSION_NAME -k writeback_pages_written -c chan1 >/dev/null 2>&1
[[ $? != 0 ]] && echo "Warning: Optional event writeback_pages_written could not be enabled, everything will still work (experimental feature)"

lttng enable-event -s $SESSION_NAME -k -c chan1 --syscall -a >/dev/null
[[ $? != 0 ]] && exit 2
# if you want to add Perf counters, do something like that :
#lttng add-context -s $SESSION_NAME -k -t perf:cache-misses -t perf:major-faults -t perf:branch-load-misses >/dev/null

lttng start $SESSION_NAME >/dev/null
[[ $? != 0 ]] && exit 2

echo -n "The trace is now recording, press ctrl+c to stop it "

while true; do
	echo -n "."
	sleep 1
done

destroy