tests: robustify strace -k tests

Allow __getpid as an alternative name for getpid,
allow __kernel_vsyscall after getpid.

* tests/strace-k.expected: New file.
* tests/strace-k-demangle.expected: Likewise.
* tests/Makefile.am (EXTRA_DIST): Add them.
* tests/strace-k-demangle.test (expected): Remove.
* tests/strace-k.test: Likewise.  Use grep to check the output.

tests/Makefile.am

@@ -392,7 +392,9 @@ EXTRA_DIST = \
 	strace-E.expected \
 	strace-T.expected \
 	strace-ff.expected \
+	strace-k-demangle.expected \
 	strace-k-demangle.test \
+	strace-k.expected \
 	strace-k.test \
 	strace-r.expected \
 	strace.supp \

tests/strace-k-demangle.expected

@@ -0,0 +1 @@
+(__kernel_vsyscall )?(__)?getpid ns::f3\(int\) ns::f2\(int\) ns::f1\(int\) ns::f0\(int\) main

tests/strace-k-demangle.test

@@ -2,6 +2,5 @@
 # Check strace -k symbol names demangling.
 
 test_prog=../stack-fcall-mangled
-expected='getpid ns::f3(int) ns::f2(int) ns::f1(int) ns::f0(int) main '
 
 . "${srcdir=.}"/strace-k.test

tests/strace-k.expected

@@ -0,0 +1 @@
+(__kernel_vsyscall )?(__)?getpid f3 f2 f1 f0 main

tests/strace-k.test

@@ -35,20 +35,21 @@
 [ -f /proc/self/maps ] ||
 	framework_skip_ '/proc/self/maps is not available'
 
+check_prog grep
 check_prog sed
 check_prog tr
 
-: ${test_prog=../stack-fcall}
-: ${expected='getpid f3 f2 f1 f0 main '}
-
-run_prog "$test_prog"
+run_prog "${test_prog=../stack-fcall}"
 run_strace -e getpid -k $args
 
-result=$(sed -r -n '1,/\(main\+0x[a-f0-9]+\) .*/ s/^[^(]+\(([^+]+)\+0x[a-f0-9]+\) .*/\1/p' "$LOG" |
-	tr '\n' ' ')
+expected="$srcdir/$NAME.expected"
+sed -r -n '1,/\(main\+0x[a-f0-9]+\) .*/ s/^[^(]+\(([^+]+)\+0x[a-f0-9]+\) .*/\1/p' "$LOG" |
+	tr '\n' ' ' |sed 's/ $//' > "$OUT"
 
-test "$result" = "$expected" || {
-	echo "expected: \"$expected\""
-	echo "result: \"$result\""
+LC_ALL=C grep -E -x -f "$expected" < "$OUT" > /dev/null || {
+	cat >&2 <<__EOF__
+Failed pattern of expected output: $(cat "$expected")
+Actual output: $(cat "$OUT")
+__EOF__
 	dump_log_and_fail_with "$STRACE $args output mismatch"
 }