1#!/bin/sh
2# probe libc's inet_pton & backtrace it with ping
3
4# Installs a probe on libc's inet_pton function, that will use uprobes,
5# then use 'perf trace' on a ping to localhost asking for just one packet
6# with the a backtrace 3 levels deep, check that it is what we expect.
7# This needs no debuginfo package, all is done using the libc ELF symtab
8# and the CFI info in the binaries.
9
10# SPDX-License-Identifier: GPL-2.0
11# Arnaldo Carvalho de Melo <acme@kernel.org>, 2017
12
13. $(dirname $0)/lib/probe.sh
14
15libc=$(grep -w libc /proc/self/maps | head -1 | sed -r 's/.*[[:space:]](\/.*)/\1/g')
16nm -Dg $libc 2>/dev/null | fgrep -q inet_pton || exit 254
17
18event_pattern='probe_libc:inet_pton(\_[[:digit:]]+)?'
19
20add_libc_inet_pton_event() {
21
22	event_name=$(perf probe -f -x $libc -a inet_pton 2>&1 | tail -n +2 | head -n -5 | \
23			grep -P -o "$event_pattern(?=[[:space:]]\(on inet_pton in $libc\))")
24
25	if [ $? -ne 0 -o -z "$event_name" ] ; then
26		printf "FAIL: could not add event\n"
27		return 1
28	fi
29}
30
31trace_libc_inet_pton_backtrace() {
32
33	expected=`mktemp -u /tmp/expected.XXX`
34
35	echo "ping[][0-9 \.:]+$event_name: \([[:xdigit:]]+\)" > $expected
36	echo ".*inet_pton\+0x[[:xdigit:]]+[[:space:]]\($libc|inlined\)$" >> $expected
37	case "$(uname -m)" in
38	s390x)
39		eventattr='call-graph=dwarf,max-stack=4'
40		echo "gaih_inet.*\+0x[[:xdigit:]]+[[:space:]]\($libc|inlined\)$" >> $expected
41		echo "(__GI_)?getaddrinfo\+0x[[:xdigit:]]+[[:space:]]\($libc|inlined\)$" >> $expected
42		echo "main\+0x[[:xdigit:]]+[[:space:]]\(.*/bin/ping.*\)$" >> $expected
43		;;
44	ppc64|ppc64le)
45		eventattr='max-stack=4'
46		echo "gaih_inet.*\+0x[[:xdigit:]]+[[:space:]]\($libc\)$" >> $expected
47		echo "getaddrinfo\+0x[[:xdigit:]]+[[:space:]]\($libc\)$" >> $expected
48		echo ".*(\+0x[[:xdigit:]]+|\[unknown\])[[:space:]]\(.*/bin/ping.*\)$" >> $expected
49		;;
50	*)
51		eventattr='max-stack=3'
52		echo "getaddrinfo\+0x[[:xdigit:]]+[[:space:]]\($libc\)$" >> $expected
53		echo ".*(\+0x[[:xdigit:]]+|\[unknown\])[[:space:]]\(.*/bin/ping.*\)$" >> $expected
54		;;
55	esac
56
57	perf_data=`mktemp -u /tmp/perf.data.XXX`
58	perf_script=`mktemp -u /tmp/perf.script.XXX`
59	perf record -e $event_name/$eventattr/ -o $perf_data ping -6 -c 1 ::1 > /dev/null 2>&1
60	perf script -i $perf_data > $perf_script
61
62	exec 3<$perf_script
63	exec 4<$expected
64	while read line <&3 && read -r pattern <&4; do
65		[ -z "$pattern" ] && break
66		echo $line
67		echo "$line" | egrep -q "$pattern"
68		if [ $? -ne 0 ] ; then
69			printf "FAIL: expected backtrace entry \"%s\" got \"%s\"\n" "$pattern" "$line"
70			return 1
71		fi
72	done
73
74	# If any statements are executed from this point onwards,
75	# the exit code of the last among these will be reflected
76	# in err below. If the exit code is 0, the test will pass
77	# even if the perf script output does not match.
78}
79
80delete_libc_inet_pton_event() {
81
82	if [ -n "$event_name" ] ; then
83		perf probe -q -d $event_name
84	fi
85}
86
87# Check for IPv6 interface existence
88ip a sh lo | fgrep -q inet6 || exit 2
89
90skip_if_no_perf_probe && \
91add_libc_inet_pton_event && \
92trace_libc_inet_pton_backtrace
93err=$?
94rm -f ${perf_data} ${perf_script} ${expected}
95delete_libc_inet_pton_event
96exit $err
97