2 # probe libc's inet_pton & backtrace it with ping
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.
10 # SPDX-License-Identifier: GPL-2.0
11 # Arnaldo Carvalho de Melo <acme@kernel.org>, 2017
13 . $(dirname $0)/lib/probe.sh
15 libc=$(grep -w libc /proc/self/maps | head -1 | sed -r 's/.*[[:space:]](\/.*)/\1/g')
16 nm -Dg $libc 2>/dev/null | fgrep -q inet_pton || exit 254
18 event_pattern='probe_libc:inet_pton(\_[[:digit:]]+)?'
20 add_libc_inet_pton_event() {
22 event_name=$(perf probe -f -x $libc -a inet_pton 2>&1 | tail -n +2 | head -n -5 | \
23 grep -P -o "$event_pattern(?=[[:space:]]\(on inet_pton in $libc\))")
25 if [ $? -ne 0 -o -z "$event_name" ] ; then
26 printf "FAIL: could not add event\n"
31 trace_libc_inet_pton_backtrace() {
33 expected=`mktemp -u /tmp/expected.XXX`
35 echo "ping[][0-9 \.:]+$event_name: \([[:xdigit:]]+\)" > $expected
36 echo ".*inet_pton\+0x[[:xdigit:]]+[[:space:]]\($libc|inlined\)$" >> $expected
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
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
51 eventattr='max-stack=3'
52 echo "getaddrinfo\+0x[[:xdigit:]]+[[:space:]]\($libc\)$" >> $expected
53 echo ".*(\+0x[[:xdigit:]]+|\[unknown\])[[:space:]]\(.*/bin/ping.*\)$" >> $expected
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 > $perf_script
64 while read line <&3 && read -r pattern <&4; do
65 [ -z "$pattern" ] && break
67 echo "$line" | egrep -q "$pattern"
68 if [ $? -ne 0 ] ; then
69 printf "FAIL: expected backtrace entry \"%s\" got \"%s\"\n" "$pattern" "$line"
74 # If any statements are executed from this point onwards,
75 # the exit code of the last among these will be reflected
76 # in err below. If the exit code is 0, the test will pass
77 # even if the perf script output does not match.
80 delete_libc_inet_pton_event() {
82 if [ -n "$event_name" ] ; then
83 perf probe -q -d $event_name
87 # Check for IPv6 interface existence
88 ip a sh lo | fgrep -q inet6 || exit 2
90 skip_if_no_perf_probe && \
91 add_libc_inet_pton_event && \
92 trace_libc_inet_pton_backtrace
94 rm -f ${perf_data} ${perf_script} ${expected}
95 delete_libc_inet_pton_event