gdb_backtrace

#!/bin/sh

BASENAME=`basename $0`

unset LD_PRELOAD

if [ -n "$VALGRIND" -o -n "$SMBD_VALGRIND" ]; then
	echo "${BASENAME}: Not running debugger under valgrind"
	exit 1
fi

if [ "x$PLEASE_NO_GDB_BACKTRACE" != "x" ]; then
	echo "${BASENAME}: Not running debugger because PLEASE_NO_GDB_BACKTRACE is set"
        exit 0
fi


# we want everything on stderr, so the program is not disturbed
exec 1>&2

UNAME=`uname`

PID=$1
BINARY=$2

test x"${PID}" = x"" && {
	echo "Usage: ${BASENAME} <pid> [<binary>]"
	exit 1
}

DB_LIST="gdb"
case "${UNAME}" in
	#
	# on Tru64 we need to try ladebug first
	# because gdb crashes itself...
	#
	OSF1)
		DB_LIST="ladebug ${DB_LIST}"
	;;
	#
	# On solaris dbx is working way more better than gdb
	# let's try it first
	#
	SunOS)
		DB_LIST="dbx ${DB_LIST}"
	;;
	#
	# FreeBSD comes with a flavor that works gdb66 and one that don't gdb
	# (gdb 6.1) let's try it first the one that works !
	#
	FreeBSD)
		DB_LIST="gdb66 ${DB_LIST}"
	;;
esac

for DB in ${DB_LIST}; do
	DB_BIN=`which ${DB} 2>/dev/null | grep '^/'`
	test x"${DB_BIN}" != x"" && {
		break
	}
done

test x"${DB_BIN}" = x"" && {
	echo "${BASENAME}: ERROR: No debugger found."
	exit 1
}

need_binary="no"
case "${DB}" in
# These debuggers need the process binary specified:
	ladebug)
	need_binary="yes"
	;;
	gdb66)
	need_binary="yes"
	;;
	dbx)
	need_binary="yes"
	;;
esac

test x"${need_binary}" = x"yes" && {

# we first try to use /proc/${PID}/exe or /proc/{$PID}/path for solaris
# then fallback to the binary from the commandline
# then we search for the commandline argument with
# 'which'
#
	test -f "/proc/${PID}/exe" && BINARY="/proc/${PID}/exe"
	test -f "/proc/${PID}/path/a.out" && BINARY=`ls -l /proc/${PID}/path/a.out |sed 's/.*-> //'`
	test x"${BINARY}" = x"" && BINARY="/proc/${PID}/exe"
	test -f "${BINARY}" || BINARY=`which ${BINARY}`
	
	test -f "${BINARY}" || {
	    echo "${BASENAME}: ERROR: Cannot find binary '${BINARY}'."
	    exit 1
	}
}

BATCHFILE_PRE=`mktemp --tmpdir gdb_backtrace_pre.XXXXXXXXXX`
test -n "${BATCHFILE_PRE}" || {
	echo "mktemp doesn't work" 1>&2
	exit 1
}
BATCHFILE_MAIN=`mktemp --tmpdir gdb_backtrace_main.XXXXXXXXXX`
test -n "${BATCHFILE_MAIN}" || {
	echo "mktemp doesn't work" 1>&2
	exit 1
}
case "${DB}" in
	ladebug)
cat << EOF  > ${BATCHFILE_PRE}
set \$stoponattach
EOF

cat << EOF  > ${BATCHFILE_MAIN}
where
quit
EOF
	${DB_BIN} -c "${BATCHFILE_MAIN}" -i "${BATCHFILE_PRE}" -pid "${PID}" "${BINARY}"
	;;
	gdb66)
cat << EOF  > ${BATCHFILE_MAIN}
set height 1000
bt full
info locals
kill
quit
EOF
	${DB_BIN} -x "${BATCHFILE_MAIN}" "${BINARY}" "${PID}"
	;;
	gdb)
cat << EOF  > ${BATCHFILE_MAIN}
set height 0
bt full
thread apply all bt full
info locals
quit
EOF
	${DB_BIN} -batch -x "${BATCHFILE_MAIN}" --pid "${PID}" < /dev/null
	;;
dbx)
	${DB_BIN} "where;dump;kill;quit" "${BINARY}" "${PID}"
	;;
esac
/bin/rm -f ${BATCHFILE_PRE} ${BATCHFILE_MAIN}