#!/bin/sh
# probe libc's inet_pton & backtrace it with ping
# Installs a probe on libc's inet_pton function, that will use uprobes,
# then use 'perf trace' on a ping to localhost asking for just one packet
# with the a backtrace 3 levels deep, check that it is what we expect.
# This needs no debuginfo package, all is done using the libc ELF symtab
# and the CFI info in the binaries.
# SPDX-License-Identifier: GPL-2.0
# Arnaldo Carvalho de Melo <[email protected]>, 2017
# shellcheck source=lib/probe.sh
. "$(dirname "$0")/lib/probe.sh"
# shellcheck source=lib/probe_vfs_getname.sh
. "$(dirname "$0")/lib/probe_vfs_getname.sh"
libc=$(grep -w libc /proc/self/maps | head -1 | sed -r 's/.*[[:space:]](\/.*)/\1/g')
nm -Dg $libc 2>/dev/null | grep -F -q inet_pton || exit 254
event_pattern='probe_libc:inet_pton(\_[[:digit:]]+)?'
add_libc_inet_pton_event() {
event_name=$(perf probe -f -x $libc -a inet_pton 2>&1 | tail -n +2 | head -n -5 | \
grep -P -o "$event_pattern(?=[[:space:]]\(on inet_pton in $libc\))")
if [ $? -ne 0 ] || [ -z "$event_name" ] ; then
printf "FAIL: could not add event\n"
return 1
fi
}
trace_libc_inet_pton_backtrace() {
expected=`mktemp -u /tmp/expected.XXX`
echo "ping[][0-9 \.:]+$event_name: \([[:xdigit:]]+\)" > $expected
echo ".*inet_pton\+0x[[:xdigit:]]+[[:space:]]\($libc|inlined\)$" >> $expected
case "$(uname -m)" in
s390x)
eventattr='call-graph=dwarf,max-stack=4'
echo "(__GI_)?getaddrinfo\+0x[[:xdigit:]]+[[:space:]]\($libc|inlined\)$" >> $expected
echo "main\+0x[[:xdigit:]]+[[:space:]]\(.*/bin/ping.*\)$" >> $expected
;;
ppc64|ppc64le)
eventattr='max-stack=4'
# Add gaih_inet to expected backtrace only if it is part of libc.
if nm $libc | grep -F -q gaih_inet.; then
echo "gaih_inet.*\+0x[[:xdigit:]]+[[:space:]]\($libc\)$" >> $expected
fi
echo "getaddrinfo\+0x[[:xdigit:]]+[[:space:]]\($libc\)$" >> $expected
echo ".*(\+0x[[:xdigit:]]+|\[unknown\])[[:space:]]\(.*/bin/ping.*\)$" >> $expected
;;
*)
eventattr='max-stack=3'
echo ".*(\+0x[[:xdigit:]]+|\[unknown\])[[:space:]]\(.*/bin/ping.*\)$" >> $expected
;;
esac
perf_data=`mktemp -u /tmp/perf.data.XXX`
perf_script=`mktemp -u /tmp/perf.script.XXX`
# Check presence of libtraceevent support to run perf record
skip_no_probe_record_support "$event_name/$eventattr/"
if [ $? -eq 2 ]; then
echo "WARN: Skipping test trace_libc_inet_pton_backtrace. No libtraceevent support."
return 2
fi
perf record -e $event_name/$eventattr/ -o $perf_data ping -6 -c 1 ::1 > /dev/null 2>&1
# check if perf data file got created in above step.
if [ ! -e $perf_data ]; then
printf "FAIL: perf record failed to create \"%s\" \n" "$perf_data"
return 1
fi
perf script -i $perf_data | tac | grep -m1 ^ping -B9 | tac > $perf_script
exec 3<$perf_script
exec 4<$expected
while read line <&3 && read -r pattern <&4; do
[ -z "$pattern" ] && break
echo $line
echo "$line" | grep -E -q "$pattern"
if [ $? -ne 0 ] ; then
printf "FAIL: expected backtrace entry \"%s\" got \"%s\"\n" "$pattern" "$line"
return 1
fi
done
# If any statements are executed from this point onwards,
# the exit code of the last among these will be reflected
# in err below. If the exit code is 0, the test will pass
# even if the perf script output does not match.
}
delete_libc_inet_pton_event() {
if [ -n "$event_name" ] ; then
perf probe -q -d $event_name
fi
}
# Check for IPv6 interface existence
ip a sh lo | grep -F -q inet6 || exit 2
skip_if_no_perf_probe && \
add_libc_inet_pton_event && \
trace_libc_inet_pton_backtrace
err=$?
rm -f ${perf_data} ${perf_script} ${expected}
delete_libc_inet_pton_event
exit $err