[PATCH 2/2] perf test shell: make perf inet_pton test more portable

[Kim Phillips <kim.phillips@arm.com>]

Debian based systems such as Ubuntu have dash as their default shell.
Even if the normal or root user's shell is bash, certain scripts still
call /bin/sh, which points to dash, so we fix this perf test by
rewriting it in a more portable way.

BEFORE:

$ sudo ./perf test -v 64
64: probe libc's inet_pton & backtrace it with ping       :
--- start ---
test child forked, pid 31942
./tests/shell/record+probe_libc_inet_pton.sh: 18: ./tests/shell/record+probe_libc_inet_pton.sh: expected[0]=ping[][0-9 \.:]+probe_libc:inet_pton: \([[:xdigit:]]+\): not found
./tests/shell/record+probe_libc_inet_pton.sh: 19: ./tests/shell/record+probe_libc_inet_pton.sh: expected[1]=.*inet_pton\+0x[[:xdigit:]]+[[:space:]]\(/lib/x86_64-linux-gnu/libc-2.27.so|inlined\)$: not found
./tests/shell/record+probe_libc_inet_pton.sh: 29: ./tests/shell/record+probe_libc_inet_pton.sh: expected[2]=getaddrinfo\+0x[[:xdigit:]]+[[:space:]]\(/lib/x86_64-linux-gnu/libc-2.27.so\)$: not found
./tests/shell/record+probe_libc_inet_pton.sh: 30: ./tests/shell/record+probe_libc_inet_pton.sh: expected[3]=.*\+0x[[:xdigit:]]+[[:space:]]\(.*/bin/ping.*\)$: not found
ping 31963 [004] 83577.670613: probe_libc:inet_pton: (7fe15f87f4b0)
./tests/shell/record+probe_libc_inet_pton.sh: 39: ./tests/shell/record+probe_libc_inet_pton.sh: Bad substitution
./tests/shell/record+probe_libc_inet_pton.sh: 41: ./tests/shell/record+probe_libc_inet_pton.sh: Bad substitution
test child finished with -2
---- end ----
probe libc's inet_pton & backtrace it with ping: Skip

AFTER:

64: probe libc's inet_pton & backtrace it with ping       :
--- start ---
test child forked, pid 32277
ping 32295 [001] 83679.690020: probe_libc:inet_pton: (7ff244f504b0)
7ff244f504b0 __GI___inet_pton+0x0 (/lib/x86_64-linux-gnu/libc-2.27.so)
7ff244f14ce4 getaddrinfo+0x124 (/lib/x86_64-linux-gnu/libc-2.27.so)
556ac036b57d _init+0xb75 (/bin/ping)
test child finished with 0
---- end ----
probe libc's inet_pton & backtrace it with ping: Ok

Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Thomas Richter <tmricht@linux.vnet.ibm.com>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: "Hendrik Brückner" <brueckner@linux.vnet.ibm.com>
Cc: Sandipan Das <sandipan@linux.vnet.ibm.com>
Signed-off-by: Kim Phillips <kim.phillips@arm.com>
---
Fixed using fake array technique described here:

https://www.linuxquestions.org/questions/programming-9/basic-bash-how-to-use-eval-to-evaluate-variable-names-made-of-arbitrary-strings-775622/

Note that bashisms can also be found with 'checkbashisms':

$ checkbashisms record+probe_libc_inet_pton.sh
script record+probe_libc_inet_pton.sh does not appear to have a #! interpreter line;
you may get strange results
possible bashism in record+probe_libc_inet_pton.sh line 18 (bash arrays, H[0]):
	expected[0]="ping[][0-9 \.:]+probe_libc:inet_pton: \([[:xdigit:]]+\)"
possible bashism in record+probe_libc_inet_pton.sh line 19 (bash arrays, H[0]):
	expected[1]=".*inet_pton\+0x[[:xdigit:]]+[[:space:]]\($libc|inlined\)$"
possible bashism in record+probe_libc_inet_pton.sh line 23 (bash arrays, H[0]):
		expected[2]="gaih_inet.*\+0x[[:xdigit:]]+[[:space:]]\($libc|inlined\)$"
possible bashism in record+probe_libc_inet_pton.sh line 24 (bash arrays, H[0]):
		expected[3]="(__GI_)?getaddrinfo\+0x[[:xdigit:]]+[[:space:]]\($libc|inlined\)$"
possible bashism in record+probe_libc_inet_pton.sh line 25 (bash arrays, H[0]):
		expected[4]="main\+0x[[:xdigit:]]+[[:space:]]\(.*/bin/ping.*\)$"
possible bashism in record+probe_libc_inet_pton.sh line 29 (bash arrays, H[0]):
		expected[2]="getaddrinfo\+0x[[:xdigit:]]+[[:space:]]\($libc\)$"
possible bashism in record+probe_libc_inet_pton.sh line 30 (bash arrays, H[0]):
		expected[3]=".*\+0x[[:xdigit:]]+[[:space:]]\(.*/bin/ping.*\)$"
possible bashism in record+probe_libc_inet_pton.sh line 39 (bash arrays, ${name[0|*|@]}):
		echo "$line" | egrep -q "${expected[$idx]}"
possible bashism in record+probe_libc_inet_pton.sh line 41 (bash arrays, ${name[0|*|@]}):
			printf "FAIL: expected backtrace entry %d \"%s\" got \"%s\"\n" $idx "${expected[$idx]}" "$line"
possible bashism in record+probe_libc_inet_pton.sh line 44 (let ...):
		let idx+=1
possible bashism in record+probe_libc_inet_pton.sh line 45 (bash arrays, ${name[0|*|@]}):
		[ -z "${expected[$idx]}" ] && break

 .../shell/record+probe_libc_inet_pton.sh      | 23 ++++++++++---------
 1 file changed, 12 insertions(+), 11 deletions(-)

diff --git a/tools/perf/tests/shell/record+probe_libc_inet_pton.sh b/tools/perf/tests/shell/record+probe_libc_inet_pton.sh
index 263057039693..41124fa12913 100755
--- a/tools/perf/tests/shell/record+probe_libc_inet_pton.sh
+++ b/tools/perf/tests/shell/record+probe_libc_inet_pton.sh
@@ -15,19 +15,20 @@ nm -Dg $libc 2>/dev/null | fgrep -q inet_pton || exit 254
 
 trace_libc_inet_pton_backtrace() {
 	idx=0
-	expected[0]="ping[][0-9 \.:]+probe_libc:inet_pton: \([[:xdigit:]]+\)"
-	expected[1]=".*inet_pton\+0x[[:xdigit:]]+[[:space:]]\($libc|inlined\)$"
+	expected='expected'
+	eval ${expected}0="'ping[][0-9 \.:]+probe_libc:inet_pton: \([[:xdigit:]]+\)'"
+	eval ${expected}1="'.*inet_pton\+0x[[:xdigit:]]+[[:space:]]\($libc|inlined\)$'"
 	case "$(uname -m)" in
 	s390x)
 		eventattr='call-graph=dwarf,max-stack=4'
-		expected[2]="gaih_inet.*\+0x[[:xdigit:]]+[[:space:]]\($libc|inlined\)$"
-		expected[3]="(__GI_)?getaddrinfo\+0x[[:xdigit:]]+[[:space:]]\($libc|inlined\)$"
-		expected[4]="main\+0x[[:xdigit:]]+[[:space:]]\(.*/bin/ping.*\)$"
+		eval ${expected}2="'gaih_inet.*\+0x[[:xdigit:]]+[[:space:]]\($libc|inlined\)$'"
+		eval ${expected}3="'(__GI_)?getaddrinfo\+0x[[:xdigit:]]+[[:space:]]\($libc|inlined\)$'"
+		eval ${expected}4="'main\+0x[[:xdigit:]]+[[:space:]]\(.*/bin/ping.*\)$'"
 		;;
 	*)
 		eventattr='max-stack=3'
-		expected[2]="getaddrinfo\+0x[[:xdigit:]]+[[:space:]]\($libc\)$"
-		expected[3]=".*\+0x[[:xdigit:]]+[[:space:]]\(.*/bin/ping.*\)$"
+		eval ${expected}2="'getaddrinfo\+0x[[:xdigit:]]+[[:space:]]\($libc\)$'"
+		eval ${expected}3="'.*\+0x[[:xdigit:]]+[[:space:]]\(.*/bin/ping.*\)$'"
 		;;
 	esac
 
@@ -36,13 +37,13 @@ trace_libc_inet_pton_backtrace() {
 	perf record -e probe_libc:inet_pton/$eventattr/ -o $file ping -6 -c 1 ::1 > /dev/null 2>&1
 	perf script -i $file | while read line ; do
 		echo $line
-		echo "$line" | egrep -q "${expected[$idx]}"
+		echo "$line" | egrep -q "$(echo $(eval echo \$$expected${idx}))"
 		if [ $? -ne 0 ] ; then
-			printf "FAIL: expected backtrace entry %d \"%s\" got \"%s\"\n" $idx "${expected[$idx]}" "$line"
+			printf "FAIL: expected backtrace entry %d \"%s\" got \"%s\"\n" $idx "$(echo $(eval echo \$$expected${idx}))" "$line"
 			exit 1
 		fi
-		let idx+=1
-		[ -z "${expected[$idx]}" ] && break
+		idx=$((idx+1))
+		[ -z "$(echo $(eval echo \$$expected${idx}))" ] && break
 	done
 
 	# If any statements are executed from this point onwards,
-- 
2.17.1