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 # shellcheck source=lib/probe.sh
14 . "$(dirname "$0")/lib/probe.sh"
15 # shellcheck source=lib/probe_vfs_getname.sh
16 . "$(dirname "$0")/lib/probe_vfs_getname.sh"
18 libc=$(grep -w libc /proc/self/maps | head -1 | sed -r 's/.*[[:space:]](\/.*)/\1/g')
19 nm -Dg $libc 2>/dev/null | grep -F -q inet_pton || exit 254
21 event_pattern='probe_libc:inet_pton(\_[[:digit:]]+)?'
23 add_libc_inet_pton_event() {
25 event_name=$(perf probe -f -x $libc -a inet_pton 2>&1 | tail -n +2 | head -n -5 | \
26 grep -P -o "$event_pattern(?=[[:space:]]\(on inet_pton in $libc\))")
28 if [ $? -ne 0 ] || [ -z "$event_name" ] ; then
29 printf "FAIL: could not add event\n"
34 trace_libc_inet_pton_backtrace() {
36 expected=`mktemp -u /tmp/expected.XXX`
38 echo "ping[][0-9 \.:]+$event_name: \([[:xdigit:]]+\)" > $expected
39 echo ".*inet_pton\+0x[[:xdigit:]]+[[:space:]]\($libc|inlined\)$" >> $expected
42 eventattr='call-graph=dwarf,max-stack=4'
43 echo "(__GI_)?getaddrinfo\+0x[[:xdigit:]]+[[:space:]]\($libc|inlined\)$" >> $expected
44 echo "main\+0x[[:xdigit:]]+[[:space:]]\(.*/bin/ping.*\)$" >> $expected
47 eventattr='max-stack=4'
48 # Add gaih_inet to expected backtrace only if it is part of libc.
49 if nm $libc | grep -F -q gaih_inet.; then
50 echo "gaih_inet.*\+0x[[:xdigit:]]+[[:space:]]\($libc\)$" >> $expected
52 echo "getaddrinfo\+0x[[:xdigit:]]+[[:space:]]\($libc\)$" >> $expected
53 echo ".*(\+0x[[:xdigit:]]+|\[unknown\])[[:space:]]\(.*/bin/ping.*\)$" >> $expected
56 eventattr='max-stack=3'
57 echo ".*(\+0x[[:xdigit:]]+|\[unknown\])[[:space:]]\(.*/bin/ping.*\)$" >> $expected
61 perf_data=`mktemp -u /tmp/perf.data.XXX`
62 perf_script=`mktemp -u /tmp/perf.script.XXX`
64 # Check presence of libtraceevent support to run perf record
65 skip_no_probe_record_support "$event_name/$eventattr/"
66 [ $? -eq 2 ] && return 2
68 perf record -e $event_name/$eventattr/ -o $perf_data ping -6 -c 1 ::1 > /dev/null 2>&1
69 # check if perf data file got created in above step.
70 if [ ! -e $perf_data ]; then
71 printf "FAIL: perf record failed to create \"%s\" \n" "$perf_data"
74 perf script -i $perf_data | tac | grep -m1 ^ping -B9 | tac > $perf_script
78 while read line <&3 && read -r pattern <&4; do
79 [ -z "$pattern" ] && break
81 echo "$line" | grep -E -q "$pattern"
82 if [ $? -ne 0 ] ; then
83 printf "FAIL: expected backtrace entry \"%s\" got \"%s\"\n" "$pattern" "$line"
88 # If any statements are executed from this point onwards,
89 # the exit code of the last among these will be reflected
90 # in err below. If the exit code is 0, the test will pass
91 # even if the perf script output does not match.
94 delete_libc_inet_pton_event() {
96 if [ -n "$event_name" ] ; then
97 perf probe -q -d $event_name
101 # Check for IPv6 interface existence
102 ip a sh lo | grep -F -q inet6 || exit 2
104 skip_if_no_perf_probe && \
105 add_libc_inet_pton_event && \
106 trace_libc_inet_pton_backtrace
108 rm -f ${perf_data} ${perf_script} ${expected}
109 delete_libc_inet_pton_event