1 # probe libc's inet_pton & backtrace it with ping
3 # Installs a probe on libc's inet_pton function, that will use uprobes,
4 # then use 'perf trace' on a ping to localhost asking for just one packet
5 # with the a backtrace 3 levels deep, check that it is what we expect.
6 # This needs no debuginfo package, all is done using the libc ELF symtab
7 # and the CFI info in the binaries.
9 # Arnaldo Carvalho de Melo <acme@kernel.org>, 2017
11 . $(dirname $0)/lib/probe.sh
13 libc=$(grep -w libc /proc/self/maps | head -1 | sed -r 's/.*[[:space:]](\/.*)/\1/g')
14 nm -Dg $libc 2>/dev/null | fgrep -q inet_pton || exit 254
16 trace_libc_inet_pton_backtrace() {
18 expected[0]="ping[][0-9 \.:]+probe_libc:inet_pton: \([[:xdigit:]]+\)"
19 expected[1]=".*inet_pton\+0x[[:xdigit:]]+[[:space:]]\($libc|inlined\)$"
22 eventattr='call-graph=dwarf,max-stack=4'
23 expected[2]="gaih_inet.*\+0x[[:xdigit:]]+[[:space:]]\($libc|inlined\)$"
24 expected[3]="(__GI_)?getaddrinfo\+0x[[:xdigit:]]+[[:space:]]\($libc|inlined\)$"
25 expected[4]="main\+0x[[:xdigit:]]+[[:space:]]\(.*/bin/ping.*\)$"
28 eventattr='max-stack=3'
29 expected[2]="getaddrinfo\+0x[[:xdigit:]]+[[:space:]]\($libc\)$"
30 expected[3]=".*\+0x[[:xdigit:]]+[[:space:]]\(.*/bin/ping.*\)$"
34 file=`mktemp -u /tmp/perf.data.XXX`
36 perf record -e probe_libc:inet_pton/$eventattr/ -o $file ping -6 -c 1 ::1 > /dev/null 2>&1
37 perf script -i $file | while read line ; do
39 echo "$line" | egrep -q "${expected[$idx]}"
40 if [ $? -ne 0 ] ; then
41 printf "FAIL: expected backtrace entry %d \"%s\" got \"%s\"\n" $idx "${expected[$idx]}" "$line"
45 [ -z "${expected[$idx]}" ] && break
48 # If any statements are executed from this point onwards,
49 # the exit code of the last among these will be reflected
50 # in err below. If the exit code is 0, the test will pass
51 # even if the perf script output does not match.
54 # Check for IPv6 interface existence
55 ip a sh lo | fgrep -q inet6 || exit 2
57 skip_if_no_perf_probe && \
58 perf probe -q $libc inet_pton && \
59 trace_libc_inet_pton_backtrace
62 perf probe -q -d probe_libc:inet_pton