fndump

fndump

#!/bin/bash

SELF="${0##*/}"
DEBUG=false
OBJ= SYM= PREFIX=

dbg() { $DEBUG && echo >&2 "# $@" ; }
die() { echo >&2 "ERROR: $@" ; exit 1 ; }

showhelp() {
	local ret=${1:-0}
	cat <<END
syntax:
	$SELF -h
	$SELF [-n] symbol[+offset]
	$SELF [-n] module symbol[+offset]
	$SELF [-n] module symbol[+offset] prefix

options:
	-h --help               this help
	-d --debug              more verbose

example:
	$SELF driver.o bad_bad_symbol+0x8b

END
	exit $ret
}

while [[ "${1:0:1}" = "-" ]] ; do
	case $1 in
		-h|--help)  showhelp 0 ;;
		-d|--debug) DEBUG=true ;;
		-*)         die "invalid option $1"
	esac
	shift
done

case ${#@} in
	1) SYM=$1 ;;
	2) OBJ=$1 ; SYM=$2 ;;
	3) OBJ=$1 ; SYM=$2 ; shift 2 ; PREFIX="$@" ;;
	*) showhelp 1 ;;
esac

# hack
#PREFIX="--prefix=`pwd` --prefix-strip=3"
#PREFIX="--prefix=`pwd` --prefix-strip=5"

SYM=${SYM/[0-9a-fA-F]*:/}
SYM=${SYM%/*}
OFS="${SYM#*+}"
[ "$SYM" = "$OFS" ] && OFS=0
SYM=${SYM%+*}

dbg "SYM=$SYM"
dbg "OFS=$OFS"

getrange() {
	local obj=$1
	local sym=$2
	objdump -t ${obj} | awk '
	BEGIN {
		l[0] = 0
	}
	$6 == "'"$sym"'" && $4 == ".text" {
		s[0]=strtonum("0x"$1)
		l[0]=strtonum("0x"$5)
	}
	$6 ~ "'"$sym"'" && $4 == ".text.unlikely" {
		s[1]=strtonum("0x"$1)
		l[1]=strtonum("0x"$5)
	}
	END {
		for (i in l) {
			if (l[i]) {
				e=s[i]+l[i]
				printf "%x %x\n", s[i], e
				exit
			}
		}
	}'
}

RANGE=()
if test -n "${OBJ}" ; then
	dbg "OBJ=$OBJ"
	test -r ${OBJ} || die "module '${OBJ}' cannot be read"
	RANGE=( $(getrange $OBJ $SYM) )
	dbg "RANGE=( ${RANGE[*]} )"
	if [ ${#RANGE[@]} != 2 ] ; then
		die "cannot find symbol ${SYM} in ${OBJ}; RANGE='${RANGE[*]}'"
	fi
else
	OBJS=()
	OBJS+=( $(find . -name '*.ko' ) )
	OBJS+=( $(find . -name '*.o' ) )
	dbg "OBJS=( ${OBJS[*]} )"
	for OBJ in ${OBJS[@]} ; do
		RANGE=( $(getrange $OBJ $SYM) )
		dbg "$OBJ: RANGE=( ${RANGE[*]} )"
		[ ${#RANGE[@]} = 2 ] && break
	done
	if [ ${#RANGE[@]} != 2 ] ; then
		die "cannot find symbol ${SYM} anywhere"
	fi
fi


OPTIONS="--start-address=0x${RANGE[0]} --stop-address=0x${RANGE[1]}"

BASE=${RANGE[0]}
[ ${BASE:0:2} = 0x ] || BASE=0x$BASE
[ ${OFS:0:2} = 0x ] || OFS=0x${OFS:-0}
OFFSET=$( printf '%x' $(( ${OFS} + $BASE )) )

CMD="objdump -S -l $PREFIX $OBJ $OPTIONS"

dbg ">>> $OBJ $SYM +$OFS (${RANGE[*]}) $OFFSET <<<"
dbg ">>> $CMD <<<"

if [ -t 0 ] && [ -t 1 ] ; then
	$CMD | vim -c ':set ft=cmix' -c "/^ \+${OFFSET}:.*$" -R -
else
	$CMD | sed -e "s/^ \{,2\}\( *${OFFSET}:.*\)$/->\1      ******/;"
fi