1#!/bin/sh
2# probe libc's inet_pton & backtrace it with ping (exclusive)
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 <[email protected]>, 2017
12
13# shellcheck source=lib/probe.sh
14. "$(dirname "$0")/lib/probe.sh"
15# shellcheck source=lib/probe_vfs_getname.sh
16. "$(dirname "$0")/lib/probe_vfs_getname.sh"
17
18libc=$(grep -w libc /proc/self/maps | head -1 | sed -r 's/.*[[:space:]](\/.*)/\1/g')
19nm -Dg $libc 2>/dev/null | grep -F -q inet_pton || exit 254
20
21event_pattern='probe_libc:inet_pton(\_[[:digit:]]+)?'
22
23add_libc_inet_pton_event() {
24
25	event_name=$(perf probe -f -x $libc -a inet_pton 2>&1 | tail -n +2 | head -n -5 | \
26			grep -P -o "$event_pattern(?=[[:space:]]\(on inet_pton in $libc\))")
27
28	if [ $? -ne 0 ] || [ -z "$event_name" ] ; then
29		printf "FAIL: could not add event\n"
30		return 1
31	fi
32}
33
34trace_libc_inet_pton_backtrace() {
35
36	expected=`mktemp -u /tmp/expected.XXX`
37
38	echo "ping[][0-9 \.:]+$event_name: \([[:xdigit:]]+\)" > $expected
39	echo ".*inet_pton\+0x[[:xdigit:]]+[[:space:]]\($libc|inlined\)$" >> $expected
40	case "$(uname -m)" in
41	s390x)
42		eventattr='call-graph=dwarf,max-stack=4'
43		echo "((__GI_)?getaddrinfo|text_to_binary_address)\+0x[[:xdigit:]]+[[:space:]]\($libc|inlined\)$" >> $expected
44		echo "(gaih_inet|main)\+0x[[:xdigit:]]+[[:space:]]\(inlined|.*/bin/ping.*\)$" >> $expected
45		;;
46	*)
47		eventattr='max-stack=4'
48		echo ".*(\+0x[[:xdigit:]]+|\[unknown\])[[:space:]]\(.*/bin/ping.*\)$" >> $expected
49		;;
50	esac
51
52	perf_data=`mktemp -u /tmp/perf.data.XXX`
53	perf_script=`mktemp -u /tmp/perf.script.XXX`
54
55	# Check presence of libtraceevent support to run perf record
56	skip_no_probe_record_support "$event_name/$eventattr/"
57	if [ $? -eq 2 ]; then
58		echo "WARN: Skipping test trace_libc_inet_pton_backtrace. No libtraceevent support."
59		return 2
60	fi
61
62	perf record -e $event_name/$eventattr/ -o $perf_data ping -6 -c 1 ::1 > /dev/null 2>&1
63	# check if perf data file got created in above step.
64	if [ ! -e $perf_data ]; then
65		printf "FAIL: perf record failed to create \"%s\" \n" "$perf_data"
66		return 1
67	fi
68	perf script -i $perf_data | tac | grep -m1 ^ping -B9 | tac > $perf_script
69
70	exec 4<$expected
71	while read -r pattern <&4; do
72		echo "Pattern: $pattern"
73		[ -z "$pattern" ] && break
74
75		found=0
76
77		# Search lines in the perf script result
78		exec 3<$perf_script
79		while read line <&3; do
80			[ -z "$line" ] && break
81			echo "  Matching: $line"
82			! echo "$line" | grep -E -q "$pattern"
83			found=$?
84			[ $found -eq 1 ] && break
85		done
86
87		if [ $found -ne 1 ] ; then
88			printf "FAIL: Didn't find the expected backtrace entry \"%s\"\n" "$pattern"
89			return 1
90		fi
91	done
92
93	# If any statements are executed from this point onwards,
94	# the exit code of the last among these will be reflected
95	# in err below. If the exit code is 0, the test will pass
96	# even if the perf script output does not match.
97}
98
99delete_libc_inet_pton_event() {
100
101	if [ -n "$event_name" ] ; then
102		perf probe -q -d $event_name
103	fi
104}
105
106# Check for IPv6 interface existence
107ip a sh lo | grep -F -q inet6 || exit 2
108
109skip_if_no_perf_probe && \
110add_libc_inet_pton_event && \
111trace_libc_inet_pton_backtrace
112err=$?
113rm -f ${perf_data} ${perf_script} ${expected}
114delete_libc_inet_pton_event
115exit $err
116