#!/bin/sh
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# probe libc's inet_pton & backtrace it with ping
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# Installs a probe on libc's inet_pton function, that will use uprobes,
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# then use 'perf trace' on a ping to localhost asking for just one packet
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# with the a backtrace 3 levels deep, check that it is what we expect.
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# This needs no debuginfo package, all is done using the libc ELF symtab
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# and the CFI info in the binaries.
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# SPDX-License-Identifier: GPL-2.0
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# Arnaldo Carvalho de Melo <acme@kernel.org>, 2017
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. $(dirname $0)/lib/probe.sh
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libc=$(grep -w libc /proc/self/maps | head -1 | sed -r 's/.*[[:space:]](\/.*)/\1/g')
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nm -Dg $libc 2>/dev/null | fgrep -q inet_pton || exit 254
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event_pattern='probe_libc:inet_pton(\_[[:digit:]]+)?'
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add_libc_inet_pton_event() {
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event_name=$(perf probe -f -x $libc -a inet_pton 2>&1 | tail -n +2 | head -n -5 | \
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grep -P -o "$event_pattern(?=[[:space:]]\(on inet_pton in $libc\))")
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if [ $? -ne 0 -o -z "$event_name" ] ; then
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printf "FAIL: could not add event\n"
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return 1
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fi
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}
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trace_libc_inet_pton_backtrace() {
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expected=`mktemp -u /tmp/expected.XXX`
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echo "ping[][0-9 \.:]+$event_name: \([[:xdigit:]]+\)" > $expected
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echo ".*inet_pton\+0x[[:xdigit:]]+[[:space:]]\($libc|inlined\)$" >> $expected
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case "$(uname -m)" in
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s390x)
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eventattr='call-graph=dwarf,max-stack=4'
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echo "gaih_inet.*\+0x[[:xdigit:]]+[[:space:]]\($libc|inlined\)$" >> $expected
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echo "(__GI_)?getaddrinfo\+0x[[:xdigit:]]+[[:space:]]\($libc|inlined\)$" >> $expected
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echo "main\+0x[[:xdigit:]]+[[:space:]]\(.*/bin/ping.*\)$" >> $expected
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;;
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ppc64|ppc64le)
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eventattr='max-stack=4'
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echo "gaih_inet.*\+0x[[:xdigit:]]+[[:space:]]\($libc\)$" >> $expected
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echo "getaddrinfo\+0x[[:xdigit:]]+[[:space:]]\($libc\)$" >> $expected
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echo ".*(\+0x[[:xdigit:]]+|\[unknown\])[[:space:]]\(.*/bin/ping.*\)$" >> $expected
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;;
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*)
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eventattr='max-stack=3'
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echo "getaddrinfo\+0x[[:xdigit:]]+[[:space:]]\($libc\)$" >> $expected
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echo ".*(\+0x[[:xdigit:]]+|\[unknown\])[[:space:]]\(.*/bin/ping.*\)$" >> $expected
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;;
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esac
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perf_data=`mktemp -u /tmp/perf.data.XXX`
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perf_script=`mktemp -u /tmp/perf.script.XXX`
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perf record -e $event_name/$eventattr/ -o $perf_data ping -6 -c 1 ::1 > /dev/null 2>&1
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perf script -i $perf_data > $perf_script
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exec 3<$perf_script
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exec 4<$expected
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while read line <&3 && read -r pattern <&4; do
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[ -z "$pattern" ] && break
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echo $line
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echo "$line" | egrep -q "$pattern"
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if [ $? -ne 0 ] ; then
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printf "FAIL: expected backtrace entry \"%s\" got \"%s\"\n" "$pattern" "$line"
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return 1
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fi
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done
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# If any statements are executed from this point onwards,
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# the exit code of the last among these will be reflected
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# in err below. If the exit code is 0, the test will pass
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# even if the perf script output does not match.
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}
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delete_libc_inet_pton_event() {
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if [ -n "$event_name" ] ; then
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perf probe -q -d $event_name
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fi
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}
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# Check for IPv6 interface existence
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ip a sh lo | fgrep -q inet6 || exit 2
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skip_if_no_perf_probe && \
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add_libc_inet_pton_event && \
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trace_libc_inet_pton_backtrace
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err=$?
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rm -f ${perf_data} ${perf_script} ${expected}
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delete_libc_inet_pton_event
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exit $err
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