#!/bin/bash
# Install abrt coredump hook
#
# chkconfig: 35 82 16
# description: Installs coredump handler which saves segfault data
### BEGIN INIT INFO
# Provides: abrt-ccpp
# Required-Start: $abrtd
# Default-Stop: 0 1 2 6
# Default-Start: 3 5
# Short-Description: Installs coredump handler which saves segfault data
# Description: Installs coredump handler which saves segfault data
### END INIT INFO

# Source function library.
. /etc/rc.d/init.d/functions

# For debugging
dry_run=false
verbose=false

# We don't have pid files, therefore have to use
# a flag file in /var/lock/subsys to enable GUI service tools
# to figure out our status
LOCK="/var/lock/subsys/abrt-ccpp"

PATTERN_FILE="/proc/sys/kernel/core_pattern"
SAVED_PATTERN_FILE="/var/run/abrt/saved_core_pattern"
HOOK_BIN="/usr/libexec/abrt-hook-ccpp"
PATTERN="|$HOOK_BIN /var/spool/abrt %s %c %p %u %g %t %h %e"

# core_pipe_limit specifies how many dump_helpers can run at the same time
# 0 - means unlimited, but it's not guaranteed that /proc/<pid> of crashing
#     process will be available for dump_helper.
# 4 - means that 4 dump_helpers can run at the same time (the rest will also
#     run, but they will fail to read /proc/<pid>).
#
# This should be enough for ABRT, we can miss some crashes, but what are
# the odds that more processes crash at the same time? And moreover,
# do people want to save EVERY ONE of the crashes when they have
# a crash storm? I don't think so.
# The value of 4 has been recommended by nhorman.
#
CORE_PIPE_LIMIT_FILE="/proc/sys/kernel/core_pipe_limit"
CORE_PIPE_LIMIT="4"

RETVAL=0

check() {
	# Check that we're a privileged user
	[ "`id -u`" = 0 ] || exit 4
}

start() {
	check

	cur=`cat "$PATTERN_FILE"`
	cur_first=`printf "%s" "$cur" | sed 's/ .*//'`

	$verbose && printf "cur:'%s'\n" "$cur"
	# Is it already installed?
	if test x"$cur_first" != x"|$HOOK_BIN"; then   # no
		# It is not installed
		printf "%s\n" "$cur" >"$SAVED_PATTERN_FILE"
		OLD_PATTERN=""
		# Does old pattern start with '|'?
		if test x"${cur#|}" = x"$cur"; then   # no
			# Encode it as hex string, NUL terminated
			OLD_PATTERN=`printf "%s" "$cur" | od -tx1 | sed 's/000[^ ]*//' | xargs | sed 's/ //g'`
			$verbose && printf "OLD_PATTERN:'%s'\n" "$OLD_PATTERN"
			OLD_PATTERN=" ${OLD_PATTERN}00"
		fi
		# Install new handler
		$verbose && printf "Installing to %s:'%s'\n" "$PATTERN_FILE" "${PATTERN}${OLD_PATTERN}"
		$dry_run || echo "${PATTERN}${OLD_PATTERN}" >"$PATTERN_FILE"
		$dry_run || touch -- "$LOCK"

		# Check core_pipe_limit and change it if it's 0,
		# otherwise the abrt-hook-ccpp won't be able to read /proc/<pid>
		# of the crashing process
		if test x"`cat "$CORE_PIPE_LIMIT_FILE"`" = x"0"; then
			echo "$CORE_PIPE_LIMIT" >"$CORE_PIPE_LIMIT_FILE"
		fi
	fi
	return $RETVAL
}

stop() {
	check

	if test -f "$SAVED_PATTERN_FILE"; then
		$verbose && printf "Restoring to %s:'%s'\n" "$PATTERN_FILE" "`cat "$SAVED_PATTERN_FILE"`"
		$dry_run || cat "$SAVED_PATTERN_FILE" >"$PATTERN_FILE"
	fi
	$dry_run || rm -f -- "$LOCK"
	return $RETVAL
}

restart() {
	stop
	start
}

reload() {
	restart
}

case "$1" in
start)
	start
	;;
stop)
	stop
	;;
reload)
	reload
	;;
force-reload)
	echo "$0: Unimplemented feature."
	RETVAL=3
	;;
restart)
	restart
	;;
condrestart)
	cur=`cat "$PATTERN_FILE"`
	cur_first=`printf "%s" "$cur" | sed 's/ .*//'`
	# Is it already installed?
	if test x"$cur_first" = x"|$HOOK_BIN"; then   # yes
		$verbose && printf "Installed, re-installing\n"
		restart
	fi
	;;
status)
	cur=`cat "$PATTERN_FILE"`
	cur_first=`printf "%s" "$cur" | sed 's/ .*//'`
	# Is it already installed?
	if test x"$cur_first" = x"|$HOOK_BIN"; then   # yes
		$verbose && printf "Installed\n"
		RETVAL=0
	else
		$verbose && printf "Not installed\n"
		RETVAL=3  # "stopped normally"
	fi
	;;
*)
	echo $"Usage: $0 {start|stop|status|restart|condrestart|reload|force-reload}"
	RETVAL=2
esac

exit $RETVAL