test: Add a test case for signal trigger

  $ uftrace -a --signal SIGUSR1@finish tests/t-signal
  # DURATION     TID     FUNCTION
              [ 13635] | main(1, 0x7ffd5c074428) {
     0.245 us [ 13635] |   foo() = 0;
     1.572 us [ 13635] |   signal(SIGUSR1, &sighandler) = 0x7f20827b9fd0;
              [ 13635] |   raise() {
              [ 13635] |     sighandler(10) {
     0.102 us [ 13635] |       bar(10);
              [ 13635] |       /* linux:task-exit */
     4.376 us [ 13635] |     } /* sighandler */

  uftrace stopped tracing with remaining functions
  ================================================
  task: 13635
  [2] sighandler
  [1] raise
  [0] main

Signed-off-by: Namhyung Kim <namhyung@gmail.com>

libmcount/mcount.c

@@ -1844,4 +1844,34 @@ TEST_CASE(mcount_thread_data)
 	return TEST_OK;
 }
 
+TEST_CASE(mcount_signal_setup)
+{
+	struct signal_trigger_item *item;
+	struct uftrace_filter_setting setting = {
+		.ptype = PATT_NONE,
+	};
+
+	/* it signal triggers are maintained in a stack (LIFO) */
+	mcount_signal_init("SIGUSR1@traceon;USR2@traceoff;RTMIN+3@finish",
+			   &setting);
+
+	item = list_first_entry(&siglist, typeof(*item), list);
+	TEST_EQ(item->sig, SIGRTMIN + 3);
+	TEST_EQ(item->tr.flags, TRIGGER_FL_FINISH);
+
+	item = list_next_entry(item, list);
+	TEST_EQ(item->sig, SIGUSR2);
+	TEST_EQ(item->tr.flags, TRIGGER_FL_TRACE_OFF);
+
+	item = list_next_entry(item, list);
+	TEST_EQ(item->sig, SIGUSR1);
+	TEST_EQ(item->tr.flags, TRIGGER_FL_TRACE_ON);
+
+	mcount_signal_finish();
+
+	TEST_EQ(list_empty(&siglist), true);
+
+	return TEST_OK;
+}
+
 #endif /* UNIT_TEST */

tests/runtest.py

@@ -166,7 +166,7 @@ def task_sort(self, output, ignore_children=False):
             # ignore result of remaining functions which follows a blank line
             if ln.strip() == '':
                 break
-            pid_patt = re.compile('[^[]*\[ *(\d+)\] |')
+            pid_patt = re.compile('[^[]+\[ *(\d+)\] |')
             m = pid_patt.match(ln)
             try:
                 pid = int(m.group(1))

tests/s-signal.c

@@ -3,12 +3,12 @@
 
 volatile int dummy;
 
-void foo(void)
+typedef void (*sighandler_t)(int sig);
+sighandler_t old_handler;
+
+int foo(void)
 {
-	if (dummy == 0)
-		dummy = 1;
-	else
-		dummy = 0;
+	return dummy;
 }
 
 void bar(int n)
@@ -19,6 +19,9 @@ void bar(int n)
 void sighandler(int sig)
 {
 	bar(sig);
+
+	if (old_handler != SIG_DFL)
+		old_handler(sig);
 }
 
 int main(int argc, char *argv[])
@@ -29,7 +32,7 @@ int main(int argc, char *argv[])
 		sig = atoi(argv[1]);
 
 	foo();
-	signal(sig, sighandler);
+	old_handler = signal(sig, sighandler);
 	raise(sig);
 	foo();
 

tests/t214_signal_trigger.py

@@ -0,0 +1,34 @@
+#!/usr/bin/env python
+
+from runtest import TestBase
+
+class TestCase(TestBase):
+    def __init__(self):
+        TestBase.__init__(self, 'signal', """
+# DURATION     TID     FUNCTION
+            [ 11892] | main() {
+   0.241 us [ 11892] |   foo();
+   1.611 us [ 11892] |   signal();
+            [ 11892] |   raise() {
+            [ 11892] |     sighandler() {
+   0.120 us [ 11892] |       bar();
+   2.315 us [ 11892] |     } /* sighandler */
+
+uftrace stopped tracing with remaining functions
+================================================
+task: 11892
+[2] sighandler
+[1] raise
+[0] main
+""")
+
+    def runcmd(self):
+        uftrace = TestBase.uftrace_cmd
+        options = "--signal SIGUSR1@finish"
+        program = 't-' + self.name
+
+        return "%s %s %s" % (uftrace, options, program)
+
+    def fixup(self, cflags, result):
+        return result.replace("""     } /* sighandler */
+""", "")