#!/bin/bash
set -e

if [[ "$1" == '-h' || $# -ne 2 ]]
then
	echo 'Usage: kill-wpull-connections (-p PID | -j JOBID | -h)'
	echo
	echo ' -h: Display this message and exit'
	echo ' -j JOBID: Kill connections of the wpull process for ArchiveBot job JOBID'
	echo ' -p PID: Kill connections of wpull process PID'
	[[ "$1" == '-h' && $# -eq 1 ]] && exit 0 || exit 1
fi

if [[ "$1" == '-p' ]]
then
	wpullPid=$2
	if [[ "${wpullPid}" == *[^0-9]* ]]
	then
		echo "Error: '${wpullPid}' is not a valid PID"
		exit 1
	fi
elif [[ "$1" == '-j' ]]
then
	pids=($(pgrep --full "wpull.*$2"))

	# Filter out this script; this is more complicated than it should be because you can't simply `| grep -v` the PID of this script. When you do that, you create a subshell, which you'd need to filter out as well.
	# Instead, we convert the list to a string of the form " 1 2 3 ", then replace " PID " by a single space, and finally convert it back to an array for counting the remaining PIDs.
	pids=" ${pids//$'\n'/ } "
	pids=(${pids/ $$ / })

	if [[ ${#pids[@]} -ne 1 ]]
	then
		echo "Error: not exactly one process found for '$2'"
		exit 1
	fi
	wpullPid=${pids[0]}
fi

if ! kill -0 ${wpullPid} >/dev/null 2>&1
then
	echo "Error: no process with PID ${wpullPid}"
	exit 1
fi

gdb -batch -batch-silent \
	-ex "attach ${wpullPid}" \
	-ex 'shell echo "FDs before forced shutdown:"; lsof -an -p '${wpullPid}' -i TCP | grep -v 127\.0\.0\.1' \
	-ex 'python import subprocess' \
	-ex 'python for fd in subprocess.check_output("lsof -an -p '${wpullPid}' -i TCP -F pfn | awk '\''NR%2==0{fd=substr($0,2)}NR%2==1&&NR>1&&!/127\.0\.0\.1/{print fd}'\''", shell = True).decode("ascii").strip().split("\n"): gdb.execute("p shutdown(" + fd + ", 2)")' \
	-ex 'shell echo "FDs after forced shutdown:"; lsof -an -p '${wpullPid}' -i TCP | grep -v 127\.0\.0\.1' \
	-ex detach \
	-ex quit