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
-g $libc 2>/dev
/null | fgrep
-q inet_pton ||
exit 254
16 trace_libc_inet_pton_backtrace
() {
18 expected
[0]="PING.*bytes"
19 expected
[1]="64 bytes from ::1.*"
20 expected
[2]=".*ping statistics.*"
21 expected
[3]=".*packets transmitted.*"
22 expected
[4]="rtt min.*"
23 expected
[5]="[0-9]+\.[0-9]+[[:space:]]+probe_libc:inet_pton:\([[:xdigit:]]+\)"
24 expected
[6]=".*inet_pton[[:space:]]\($libc\)$"
27 eventattr
='call-graph=dwarf'
28 expected
[7]="gaih_inet[[:space:]]\(inlined\)$"
29 expected
[8]="__GI_getaddrinfo[[:space:]]\(inlined\)$"
30 expected
[9]="main[[:space:]]\(.*/bin/ping.*\)$"
31 expected
[10]="__libc_start_main[[:space:]]\($libc\)$"
32 expected
[11]="_start[[:space:]]\(.*/bin/ping.*\)$"
35 eventattr
='max-stack=3'
36 expected
[7]="getaddrinfo[[:space:]]\($libc\)$"
37 expected
[8]=".*\(.*/bin/ping.*\)$"
41 perf trace
--no-syscalls -e probe_libc
:inet_pton
/$eventattr/ ping -6 -c 1 ::1 2>&1 |
grep -v ^$ |
while read line
; do
43 echo "$line" |
egrep -q "${expected[$idx]}"
44 if [ $?
-ne 0 ] ; then
45 printf "FAIL: expected backtrace entry %d \"%s\" got \"%s\"\n" $idx "${expected[$idx]}" "$line"
49 [ -z "${expected[$idx]}" ] && break
53 # Check for IPv6 interface existence
54 ip a sh lo | fgrep
-q inet6 ||
exit 2
56 skip_if_no_perf_probe
&& \
57 perf probe
-q $libc inet_pton
&& \
58 trace_libc_inet_pton_backtrace
61 perf probe
-q -d probe_libc
:inet_pton