selftests/user_events: Adapt dyn_test to non-persist events

Now that user_events does not honor persist events the dynamic_events
file cannot be easily used to test parsing and matching cases.

Update dyn_test to use the direct ABI file instead of dynamic_events so
that we still have testing coverage until persist events and
dynamic_events file integration has been decided.

Link: https://lkml.kernel.org/r/20230614163336.5797-6-beaub@linux.microsoft.com

Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

tools/testing/selftests/user_events/dyn_test.c

@@ -16,42 +16,140 @@
 
 #include "../kselftest_harness.h"
 
-const char *dyn_file = "/sys/kernel/tracing/dynamic_events";
+const char *abi_file = "/sys/kernel/tracing/user_events_data";
-const char *clear = "!u:__test_event";
+const char *enable_file = "/sys/kernel/tracing/events/user_events/__test_event/enable";
 
-static int Append(const char *value)
+static bool wait_for_delete(void)
 {
-	int fd = open(dyn_file, O_RDWR | O_APPEND);
+	int i;
-	int ret = write(fd, value, strlen(value));
+
+	for (i = 0; i < 1000; ++i) {
+		int fd = open(enable_file, O_RDONLY);
+
+		if (fd == -1)
+			return true;
+
+		close(fd);
+		usleep(1000);
+	}
+
+	return false;
+}
+
+static int reg_event(int fd, int *check, int bit, const char *value)
+{
+	struct user_reg reg = {0};
+
+	reg.size = sizeof(reg);
+	reg.name_args = (__u64)value;
+	reg.enable_bit = bit;
+	reg.enable_addr = (__u64)check;
+	reg.enable_size = sizeof(*check);
+
+	if (ioctl(fd, DIAG_IOCSREG, &reg) == -1)
+		return -1;
+
+	return 0;
+}
+
+static int unreg_event(int fd, int *check, int bit)
+{
+	struct user_unreg unreg = {0};
+
+	unreg.size = sizeof(unreg);
+	unreg.disable_bit = bit;
+	unreg.disable_addr = (__u64)check;
+
+	return ioctl(fd, DIAG_IOCSUNREG, &unreg);
+}
+
+static int parse(int *check, const char *value)
+{
+	int fd = open(abi_file, O_RDWR);
+	int ret;
+
+	if (fd == -1)
+		return -1;
+
+	/* Until we have persist flags via dynamic events, use the base name */
+	if (value[0] != 'u' || value[1] != ':') {
+		close(fd);
+		return -1;
+	}
+
+	ret = reg_event(fd, check, 31, value + 2);
+
+	if (ret != -1) {
+		if (unreg_event(fd, check, 31) == -1)
+			printf("WARN: Couldn't unreg event\n");
+	}
 
 	close(fd);
+
 	return ret;
 }
 
-#define CLEAR() \
+static int check_match(int *check, const char *first, const char *second, bool *match)
+{
+	int fd = open(abi_file, O_RDWR);
+	int ret = -1;
+
+	if (fd == -1)
+		return -1;
+
+	if (reg_event(fd, check, 31, first) == -1)
+		goto cleanup;
+
+	if (reg_event(fd, check, 30, second) == -1) {
+		if (errno == EADDRINUSE) {
+			/* Name is in use, with different fields */
+			*match = false;
+			ret = 0;
+		}
+
+		goto cleanup;
+	}
+
+	*match = true;
+	ret = 0;
+cleanup:
+	unreg_event(fd, check, 31);
+	unreg_event(fd, check, 30);
+
+	close(fd);
+
+	wait_for_delete();
+
+	return ret;
+}
+
+#define TEST_MATCH(x, y) \
 do { \
-	int ret = Append(clear); \
+	bool match; \
-	if (ret == -1) \
+	ASSERT_NE(-1, check_match(&self->check, x, y, &match)); \
-		ASSERT_EQ(ENOENT, errno); \
+	ASSERT_EQ(true, match); \
 } while (0)
 
-#define TEST_PARSE(x) \
+#define TEST_NMATCH(x, y) \
 do { \
-	ASSERT_NE(-1, Append(x)); \
+	bool match; \
-	CLEAR(); \
+	ASSERT_NE(-1, check_match(&self->check, x, y, &match)); \
+	ASSERT_EQ(false, match); \
 } while (0)
 
-#define TEST_NPARSE(x) ASSERT_EQ(-1, Append(x))
+#define TEST_PARSE(x) ASSERT_NE(-1, parse(&self->check, x))
+
+#define TEST_NPARSE(x) ASSERT_EQ(-1, parse(&self->check, x))
 
 FIXTURE(user) {
+	int check;
 };
 
 FIXTURE_SETUP(user) {
-	CLEAR();
 }
 
 FIXTURE_TEARDOWN(user) {
-	CLEAR();
+	wait_for_delete();
 }
 
 TEST_F(user, basic_types) {
@@ -95,33 +193,30 @@ TEST_F(user, size_types) {
 	TEST_NPARSE("u:__test_event char a 20");
 }
 
-TEST_F(user, flags) {
-	/* Should work */
-	TEST_PARSE("u:__test_event:BPF_ITER u32 a");
-	/* Forward compat */
-	TEST_PARSE("u:__test_event:BPF_ITER,FLAG_FUTURE u32 a");
-}
-
 TEST_F(user, matching) {
-	/* Register */
+	/* Single name matches */
-	ASSERT_NE(-1, Append("u:__test_event struct custom a 20"));
+	TEST_MATCH("__test_event u32 a",
-	/* Should not match */
+		   "__test_event u32 a");
-	TEST_NPARSE("!u:__test_event struct custom b");
+
-	/* Should match */
+	/* Multiple names match */
-	TEST_PARSE("!u:__test_event struct custom a");
+	TEST_MATCH("__test_event u32 a; u32 b",
-	/* Multi field reg */
+		   "__test_event u32 a; u32 b");
-	ASSERT_NE(-1, Append("u:__test_event u32 a; u32 b"));
+
-	/* Non matching cases */
+	/* Multiple names match with dangling ; */
-	TEST_NPARSE("!u:__test_event u32 a");
+	TEST_MATCH("__test_event u32 a; u32 b",
-	TEST_NPARSE("!u:__test_event u32 b");
+		   "__test_event u32 a; u32 b;");
-	TEST_NPARSE("!u:__test_event u32 a; u32 ");
+
-	TEST_NPARSE("!u:__test_event u32 a; u32 a");
+	/* Single name doesn't match */
-	/* Matching case */
+	TEST_NMATCH("__test_event u32 a",
-	TEST_PARSE("!u:__test_event u32 a; u32 b");
+		    "__test_event u32 b");
-	/* Register */
+
-	ASSERT_NE(-1, Append("u:__test_event u32 a; u32 b"));
+	/* Multiple names don't match */
-	/* Ensure trailing semi-colon case */
+	TEST_NMATCH("__test_event u32 a; u32 b",
-	TEST_PARSE("!u:__test_event u32 a; u32 b;");
+		    "__test_event u32 b; u32 a");
+
+	/* Types don't match */
+	TEST_NMATCH("__test_event u64 a; u64 b",
+		    "__test_event u32 a; u32 b");
 }
 
 int main(int argc, char **argv)