1 files changed, 104 insertions, 36 deletions

diff --git a/tools/testing/selftests/kselftest_harness.h b/tools/testing/selftests/kselftest_harness.h
index 4fd735e48ee7ee..37b03f1b8741d1 100644
--- a/tools/testing/selftests/kselftest_harness.h
+++ b/tools/testing/selftests/kselftest_harness.h
@@ -51,12 +51,11 @@
 #define __KSELFTEST_HARNESS_H
 
 #ifndef _GNU_SOURCE
-#define _GNU_SOURCE
+static_assert(0, "kselftest harness requires _GNU_SOURCE to be defined");
 #endif
 #include <asm/types.h>
 #include <ctype.h>
 #include <errno.h>
-#include <limits.h>
 #include <stdbool.h>
 #include <stdint.h>
 #include <stdio.h>
@@ -67,6 +66,8 @@
 #include <sys/wait.h>
 #include <unistd.h>
 #include <setjmp.h>
+#include <syscall.h>
+#include <linux/sched.h>
 
 #include "kselftest.h"
 
@@ -81,6 +82,17 @@
 #  define TH_LOG_ENABLED 1
 #endif
 
+/* Wait for the child process to end but without sharing memory mapping. */
+static inline pid_t clone3_vfork(void)
+{
+	struct clone_args args = {
+		.flags = CLONE_VFORK,
+		.exit_signal = SIGCHLD,
+	};
+
+	return syscall(__NR_clone3, &args, sizeof(args));
+}
+
 /**
  * TH_LOG()
  *
@@ -282,6 +294,32 @@
  * A bare "return;" statement may be used to return early.
  */
 #define FIXTURE_TEARDOWN(fixture_name) \
+	static const bool fixture_name##_teardown_parent; \
+	__FIXTURE_TEARDOWN(fixture_name)
+
+/**
+ * FIXTURE_TEARDOWN_PARENT()
+ * *_metadata* is included so that EXPECT_*, ASSERT_* etc. work correctly.
+ *
+ * @fixture_name: fixture name
+ *
+ * .. code-block:: c
+ *
+ *     FIXTURE_TEARDOWN_PARENT(fixture_name) { implementation }
+ *
+ * Same as FIXTURE_TEARDOWN() but run this code in a parent process.  This
+ * enables the test process to drop its privileges without impacting the
+ * related FIXTURE_TEARDOWN_PARENT() (e.g. to remove files from a directory
+ * where write access was dropped).
+ *
+ * To make it possible for the parent process to use *self*, share (MAP_SHARED)
+ * the fixture data between all forked processes.
+ */
+#define FIXTURE_TEARDOWN_PARENT(fixture_name) \
+	static const bool fixture_name##_teardown_parent = true; \
+	__FIXTURE_TEARDOWN(fixture_name)
+
+#define __FIXTURE_TEARDOWN(fixture_name) \
 	void fixture_name##_teardown( \
 		struct __test_metadata __attribute__((unused)) *_metadata, \
 		FIXTURE_DATA(fixture_name) __attribute__((unused)) *self, \
@@ -326,7 +364,7 @@
  * variant.
  */
 #define FIXTURE_VARIANT_ADD(fixture_name, variant_name) \
-	extern FIXTURE_VARIANT(fixture_name) \
+	extern const FIXTURE_VARIANT(fixture_name) \
 		_##fixture_name##_##variant_name##_variant; \
 	static struct __fixture_variant_metadata \
 		_##fixture_name##_##variant_name##_object = \
@@ -338,7 +376,7 @@
 		__register_fixture_variant(&_##fixture_name##_fixture_object, \
 			&_##fixture_name##_##variant_name##_object);	\
 	} \
-	FIXTURE_VARIANT(fixture_name) \
+	const FIXTURE_VARIANT(fixture_name) \
 		_##fixture_name##_##variant_name##_variant =
 
 /**
@@ -356,10 +394,11 @@
  * Very similar to TEST() except that *self* is the setup instance of fixture's
  * datatype exposed for use by the implementation.
  *
- * The @test_name code is run in a separate process sharing the same memory
- * (i.e. vfork), which means that the test process can update its privileges
- * without impacting the related FIXTURE_TEARDOWN() (e.g. to remove files from
- * a directory where write access was dropped).
+ * The _metadata object is shared (MAP_SHARED) with all the potential forked
+ * processes, which enables them to use EXCEPT_*() and ASSERT_*().
+ *
+ * The *self* object is only shared with the potential forked processes if
+ * FIXTURE_TEARDOWN_PARENT() is used instead of FIXTURE_TEARDOWN().
  */
 #define TEST_F(fixture_name, test_name) \
 	__TEST_F_IMPL(fixture_name, test_name, -1, TEST_TIMEOUT_DEFAULT)
@@ -380,50 +419,71 @@
 		struct __fixture_variant_metadata *variant) \
 	{ \
 		/* fixture data is alloced, setup, and torn down per call. */ \
-		FIXTURE_DATA(fixture_name) self; \
+		FIXTURE_DATA(fixture_name) self_private, *self = NULL; \
 		pid_t child = 1; \
 		int status = 0; \
-		memset(&self, 0, sizeof(FIXTURE_DATA(fixture_name))); \
+		/* Makes sure there is only one teardown, even when child forks again. */ \
+		bool *teardown = mmap(NULL, sizeof(*teardown), \
+			PROT_READ | PROT_WRITE, MAP_SHARED | MAP_ANONYMOUS, -1, 0); \
+		*teardown = false; \
+		if (sizeof(*self) > 0) { \
+			if (fixture_name##_teardown_parent) { \
+				self = mmap(NULL, sizeof(*self), PROT_READ | PROT_WRITE, \
+					MAP_SHARED | MAP_ANONYMOUS, -1, 0); \
+			} else { \
+				memset(&self_private, 0, sizeof(self_private)); \
+				self = &self_private; \
+			} \
+		} \
 		if (setjmp(_metadata->env) == 0) { \
-			/* Use the same _metadata. */ \
-			child = vfork(); \
+			/* _metadata and potentially self are shared with all forks. */ \
+			child = clone3_vfork(); \
 			if (child == 0) { \
-				fixture_name##_setup(_metadata, &self, variant->data); \
+				fixture_name##_setup(_metadata, self, variant->data); \
 				/* Let setup failure terminate early. */ \
 				if (_metadata->exit_code) \
 					_exit(0); \
 				_metadata->setup_completed = true; \
-				fixture_name##_##test_name(_metadata, &self, variant->data); \
+				fixture_name##_##test_name(_metadata, self, variant->data); \
 			} else if (child < 0 || child != waitpid(child, &status, 0)) { \
 				ksft_print_msg("ERROR SPAWNING TEST GRANDCHILD\n"); \
 				_metadata->exit_code = KSFT_FAIL; \
 			} \
 		} \
 		if (child == 0) { \
-			if (_metadata->setup_completed && !_metadata->teardown_parent) \
-				fixture_name##_teardown(_metadata, &self, variant->data); \
+			if (_metadata->setup_completed && !fixture_name##_teardown_parent && \
+					__sync_bool_compare_and_swap(teardown, false, true)) \
+				fixture_name##_teardown(_metadata, self, variant->data); \
 			_exit(0); \
 		} \
-		if (_metadata->setup_completed && _metadata->teardown_parent) \
-			fixture_name##_teardown(_metadata, &self, variant->data); \
-		if (!WIFEXITED(status) && WIFSIGNALED(status)) \
+		if (_metadata->setup_completed && fixture_name##_teardown_parent && \
+				__sync_bool_compare_and_swap(teardown, false, true)) \
+			fixture_name##_teardown(_metadata, self, variant->data); \
+		munmap(teardown, sizeof(*teardown)); \
+		if (self && fixture_name##_teardown_parent) \
+			munmap(self, sizeof(*self)); \
+		if (WIFEXITED(status)) { \
+			if (WEXITSTATUS(status)) \
+				_metadata->exit_code = WEXITSTATUS(status); \
+		} else if (WIFSIGNALED(status)) { \
 			/* Forward signal to __wait_for_test(). */ \
 			kill(getpid(), WTERMSIG(status)); \
+		} \
 		__test_check_assert(_metadata); \
 	} \
-	static struct __test_metadata \
-		      _##fixture_name##_##test_name##_object = { \
-		.name = #test_name, \
-		.fn = &wrapper_##fixture_name##_##test_name, \
-		.fixture = &_##fixture_name##_fixture_object, \
-		.termsig = signal, \
-		.timeout = tmout, \
-		.teardown_parent = false, \
-	 }; \
+	static struct __test_metadata *_##fixture_name##_##test_name##_object; \
 	static void __attribute__((constructor)) \
 			_register_##fixture_name##_##test_name(void) \
 	{ \
-		__register_test(&_##fixture_name##_##test_name##_object); \
+		struct __test_metadata *object = mmap(NULL, sizeof(*object), \
+			PROT_READ | PROT_WRITE, MAP_SHARED | MAP_ANONYMOUS, -1, 0); \
+		object->name = #test_name; \
+		object->fn = &wrapper_##fixture_name##_##test_name; \
+		object->fixture = &_##fixture_name##_fixture_object; \
+		object->termsig = signal; \
+		object->timeout = tmout; \
+		_##fixture_name##_##test_name##_object = object; \
+		__register_test(object); \
 	} \
 	static void fixture_name##_##test_name( \
 		struct __test_metadata __attribute__((unused)) *_metadata, \
@@ -831,11 +891,12 @@ struct __test_xfail {
 	{ \
 		.fixture = &_##fixture_name##_fixture_object, \
 		.variant = &_##fixture_name##_##variant_name##_object, \
-		.test = &_##fixture_name##_##test_name##_object, \
 	}; \
 	static void __attribute__((constructor)) \
 		_register_##fixture_name##_##variant_name##_##test_name##_xfail(void) \
 	{ \
+		_##fixture_name##_##variant_name##_##test_name##_xfail.test = \
+			_##fixture_name##_##test_name##_object; \
 		__register_xfail(&_##fixture_name##_##variant_name##_##test_name##_xfail); \
 	}
 
@@ -878,7 +939,6 @@ struct __test_metadata {
 	bool timed_out;	/* did this test timeout instead of exiting? */
 	bool aborted;	/* stopped test due to failed ASSERT */
 	bool setup_completed; /* did setup finish? */
-	bool teardown_parent; /* run teardown in a parent process */
 	jmp_buf env;	/* for exiting out of test early */
 	struct __test_results *results;
 	struct __test_metadata *prev, *next;
@@ -1156,16 +1216,23 @@ void __run_test(struct __fixture_metadata *f,
 		struct __test_metadata *t)
 {
 	struct __test_xfail *xfail;
-	char test_name[LINE_MAX];
+	char *test_name;
 	const char *diagnostic;
 
 	/* reset test struct */
 	t->exit_code = KSFT_PASS;
 	t->trigger = 0;
+	t->aborted = false;
+	t->setup_completed = false;
+	memset(t->env, 0, sizeof(t->env));
 	memset(t->results->reason, 0, sizeof(t->results->reason));
 
-	snprintf(test_name, sizeof(test_name), "%s%s%s.%s",
-		 f->name, variant->name[0] ? "." : "", variant->name, t->name);
+	if (asprintf(&test_name, "%s%s%s.%s", f->name,
+		variant->name[0] ? "." : "", variant->name, t->name) == -1) {
+		ksft_print_msg("ERROR ALLOCATING MEMORY\n");
+		t->exit_code = KSFT_FAIL;
+		_exit(t->exit_code);
+	}
 
 	ksft_print_msg(" RUN           %s ...\n", test_name);
 
@@ -1173,7 +1240,7 @@ void __run_test(struct __fixture_metadata *f,
 	fflush(stdout);
 	fflush(stderr);
 
-	t->pid = fork();
+	t->pid = clone3_vfork();
 	if (t->pid < 0) {
 		ksft_print_msg("ERROR SPAWNING TEST CHILD\n");
 		t->exit_code = KSFT_FAIL;
@@ -1202,7 +1269,8 @@ void __run_test(struct __fixture_metadata *f,
 		diagnostic = "unknown";
 
 	ksft_test_result_code(t->exit_code, test_name,
-			      diagnostic ? "%s" : "", diagnostic);
+			      diagnostic ? "%s" : NULL, diagnostic);
+	free(test_name);
 }
 
 static int test_harness_run(int argc, char **argv)