lib: Unit test for exit handler

Checks that
- exit handlers are run only once, even when registered multiple
  times.
- run in reverse order
- actually run for all ways a test could exit.

This is prep work to extend exit handlers to also work in a subtest
aware way.

Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>

lib/tests/.gitignore

@@ -1,6 +1,7 @@
 # Please keep sorted alphabetically
 igt_assert
 igt_fork_helper
+igt_exit_handler
 igt_invalid_subtest_name
 igt_list_only
 igt_no_exit

lib/tests/Makefile.sources

@@ -11,6 +11,7 @@ check_PROGRAMS = \
 	igt_invalid_subtest_name \
 	igt_segfault \
 	igt_assert \
+	igt_exit_handler \
 	$(NULL)
 
 check_SCRIPTS = \

lib/tests/igt_exit_handler.c

@@ -0,0 +1,128 @@
+/*
+ * Copyright © 2016 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#define _GNU_SOURCE
+#include <assert.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include "igt_core.h"
+
+int test;
+int pipes[2];
+
+static void exit_handler1(int sig)
+{
+	assert(test == 1);
+	test++;
+}
+
+static void exit_handler2(int sig)
+{
+	char tmp = 1;
+
+	/* ensure exit handlers are called in reverse */
+	assert(test == 0);
+	test++;
+
+	/* we need to get a side effect to the parent to make sure exit handlers
+	 * actually run. */
+	assert(write(pipes[1], &tmp, 1) == 1);
+}
+
+enum test_type {
+	SUC,
+	NORMAL,
+	FAIL,
+	SKIP,
+	SIG
+};
+
+static int testfunc(enum test_type test_type)
+{
+	char prog[] = "igt_no_exit";
+	char *fake_argv[] = {prog};
+	int fake_argc = 1;
+	pid_t pid;
+	int status;
+	char tmp = 0;
+
+	assert(pipe2(pipes, O_NONBLOCK) == 0);
+
+	pid = fork();
+
+	if (pid == 0) {
+		igt_subtest_init(fake_argc, fake_argv);
+
+		igt_fixture {
+			/* register twice, should only be called once */
+			igt_install_exit_handler(exit_handler1);
+			igt_install_exit_handler(exit_handler1);
+
+			igt_install_exit_handler(exit_handler2);
+		}
+
+		igt_subtest("subtest") {
+			switch (test_type) {
+			case SUC:
+				igt_success();
+			case FAIL:
+				igt_fail(1);
+			case SKIP:
+				igt_skip("skip");
+			case NORMAL:
+				break;
+			case SIG:
+				raise(SIGTERM);
+			}
+		}
+
+		igt_exit();
+	}
+
+	assert(waitpid(pid, &status, 0) != -1);
+
+	assert(read(pipes[0], &tmp, 1) == 1);
+	assert(tmp == 1);
+
+	return status;
+}
+
+int main(int argc, char **argv)
+{
+	int status;
+
+	assert(testfunc(SUC) == 0);
+
+	assert(testfunc(NORMAL) == 0);
+
+	status = testfunc(FAIL);
+	assert(WIFEXITED(status) && WEXITSTATUS(status) == 1);
+
+	status = testfunc(SKIP);
+	assert(WIFEXITED(status) && WEXITSTATUS(status) == IGT_EXIT_SKIP);
+
+	status = testfunc(SIG);
+	assert(WIFSIGNALED(status) && WTERMSIG(status) == SIGTERM);
+}