#! /bin/sh
# SPDX-License-Identifier: GPL-2.0
#
# Randy Dunlap <rdunlap@infradead.org>, 2018
# Thorsten Leemhuis <linux@leemhuis.info>, 2018

usage()
{
	cat <<EOF
usage: ${0##*/}
       ${0##*/} <int>

Call without parameters to decode /proc/sys/kernel/tainted.

Call with a positive integer as parameter to decode a value you
retrieved from /proc/sys/kernel/tainted on another system.

EOF
}

if [ "$1"x != "x" ]; then
	if  [ "$1"x == "--helpx" ] || [ "$1"x == "-hx" ] ; then
		usage
		exit 1
	elif  [ $1 -ge 0 ] 2>/dev/null ; then
		taint=$1
	else
		echo "Error: Parameter '$1' not a positive interger. Aborting." >&2
		exit 1
	fi
else
	TAINTFILE="/proc/sys/kernel/tainted"
	if [ ! -r $TAINTFILE ]; then
		echo "No file: $TAINTFILE"
		exit
	fi

	taint=`cat $TAINTFILE`
fi

if [ $taint -eq 0 ]; then
	echo "Kernel not Tainted"
	exit
else
	echo "Kernel is \"tainted\" for the following reasons:"
fi

T=$taint
out=

addout() {
	out=$out$1
}

if [ `expr $T % 2` -eq 0 ]; then
	addout "G"
else
	addout "P"
	echo " * proprietary module was loaded (#0)"
fi

T=`expr $T / 2`
if [ `expr $T % 2` -eq 0 ]; then
	addout " "
else
	addout "F"
	echo " * module was force loaded (#1)"
fi

T=`expr $T / 2`
if [ `expr $T % 2` -eq 0 ]; then
	addout " "
else
	addout "S"
	echo " * kernel running on an out of specification system (#2)"
fi

T=`expr $T / 2`
if [ `expr $T % 2` -eq 0 ]; then
	addout " "
else
	addout "R"
	echo " * module was force unloaded (#3)"
fi

T=`expr $T / 2`
if [ `expr $T % 2` -eq 0 ]; then
	addout " "
else
	addout "M"
	echo " * processor reported a Machine Check Exception (MCE) (#4)"
fi

T=`expr $T / 2`
if [ `expr $T % 2` -eq 0 ]; then
	addout " "
else
	addout "B"
	echo " * bad page referenced or some unexpected page flags (#5)"
fi

T=`expr $T / 2`
if [ `expr $T % 2` -eq 0 ]; then
	addout " "
else
	addout "U"
	echo " * taint requested by userspace application (#6)"
fi

T=`expr $T / 2`
if [ `expr $T % 2` -eq 0 ]; then
	addout " "
else
	addout "D"
	echo " * kernel died recently, i.e. there was an OOPS or BUG (#7)"
fi

T=`expr $T / 2`
if [ `expr $T % 2` -eq 0 ]; then
	addout " "
else
	addout "A"
	echo " * an ACPI table was overridden by user (#8)"
fi

T=`expr $T / 2`
if [ `expr $T % 2` -eq 0 ]; then
	addout " "
else
	addout "W"
	echo " * kernel issued warning (#9)"
fi

T=`expr $T / 2`
if [ `expr $T % 2` -eq 0 ]; then
	addout " "
else
	addout "C"
	echo " * staging driver was loaded (#10)"
fi

T=`expr $T / 2`
if [ `expr $T % 2` -eq 0 ]; then
	addout " "
else
	addout "I"
	echo " * workaround for bug in platform firmware applied (#11)"
fi

T=`expr $T / 2`
if [ `expr $T % 2` -eq 0 ]; then
	addout " "
else
	addout "O"
	echo " * externally-built ('out-of-tree') module was loaded  (#12)"
fi

T=`expr $T / 2`
if [ `expr $T % 2` -eq 0 ]; then
	addout " "
else
	addout "E"
	echo " * unsigned module was loaded (#13)"
fi

T=`expr $T / 2`
if [ `expr $T % 2` -eq 0 ]; then
	addout " "
else
	addout "L"
	echo " * soft lockup occurred (#14)"
fi

T=`expr $T / 2`
if [ `expr $T % 2` -eq 0 ]; then
	addout " "
else
	addout "K"
	echo " * kernel has been live patched (#15)"
fi

T=`expr $T / 2`
if [ `expr $T % 2` -eq 0 ]; then
	addout " "
else
	addout "X"
	echo " * auxiliary taint, defined for and used by distros (#16)"

fi
T=`expr $T / 2`
if [ `expr $T % 2` -eq 0 ]; then
	addout " "
else
	addout "T"
	echo " * kernel was built with the struct randomization plugin (#17)"
fi

echo "For a more detailed explanation of the various taint flags see"
echo " Documentation/admin-guide/tainted-kernels.rst in the the Linux kernel sources"
echo " or https://kernel.org/doc/html/latest/admin-guide/tainted-kernels.html"
echo "Raw taint value as int/string: $taint/'$out'"
#EOF#