igt/drm_read: Abuse read(drm)

Check that the more obvious userspace error conditions are handled by
the kernel, ideally without loss of data. These include nonblocking
waits, passing invalid buffers and passing buffers of the incorrect
length.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

1 files changed, 180 insertions, 0 deletions

diff --git a/tests/drm_read.c b/tests/drm_read.c
new file mode 100644
index 00000000..f88b0406
--- /dev/null
+++ b/tests/drm_read.c
@@ -0,0 +1,180 @@
+/*
+ * Copyright © 2014 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.
+ *
+ * Authors:
+ *    Chris Wilson <chris@chris-wilson.co.uk>
+ *
+ */
+
+/*
+ * Testcase: boundary testing of read(drm_fd)
+ */
+
+#include <unistd.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <string.h>
+#include <signal.h>
+#include <fcntl.h>
+#include <inttypes.h>
+#include <errno.h>
+#include <sys/stat.h>
+#include <sys/ioctl.h>
+#include <sys/time.h>
+#include <sys/poll.h>
+#include "drm.h"
+#include "ioctl_wrappers.h"
+#include "drmtest.h"
+#include "igt_aux.h"
+
+IGT_TEST_DESCRIPTION("Call read(drm) and see if it behaves.");
+
+static void sighandler(int sig)
+{
+}
+
+static void assert_empty(int fd)
+{
+	struct pollfd pfd = {fd, POLLIN};
+	do_or_die(poll(&pfd, 1, 0));
+}
+
+static void generate_event(int fd)
+{
+	union drm_wait_vblank vbl;
+
+	/* We assume that pipe 0 is running */
+
+	vbl.request.type =
+		DRM_VBLANK_RELATIVE |
+		DRM_VBLANK_EVENT;
+	vbl.request.sequence = 0;
+
+	do_ioctl(fd, DRM_IOCTL_WAIT_VBLANK, &vbl);
+}
+
+static void wait_for_event(int fd)
+{
+	struct pollfd pfd = {fd, POLLIN};
+	igt_assert(poll(&pfd, 1, -1) == 1);
+}
+
+static int setup(int in, int nonblock)
+{
+	int fd;
+
+	alarm(0);
+
+	fd = dup(in);
+	if (nonblock) {
+		int ret = -1;
+		if (fd != -1)
+			ret = fcntl(fd, F_GETFL);
+		if (ret != -1) {
+			ret |= O_NONBLOCK;
+			ret = fcntl(fd, F_SETFL, ret);
+		}
+		igt_require(ret != -1);
+	}
+
+	assert_empty(fd);
+	return fd;
+}
+
+static void teardown(int fd)
+{
+	alarm(0);
+	assert_empty(fd);
+	close(fd);
+	errno = 0;
+}
+
+static void test_invalid_buffer(int in)
+{
+	int fd = setup(in, 0);
+
+	alarm(1);
+
+	igt_assert_eq(read(fd, (void *)-1, 4096), -1);
+	igt_assert_eq(errno, EFAULT);
+
+	teardown(fd);
+}
+
+static void test_empty(int in, int nonblock, int expected)
+{
+	char buffer[1024];
+	int fd = setup(in, nonblock);
+
+	alarm(1);
+	igt_assert_eq(read(fd, buffer, sizeof(buffer)), -1);
+	igt_assert_eq(errno, expected);
+
+	teardown(fd);
+}
+
+static void test_short_buffer(int in, int nonblock)
+{
+	char buffer[1024]; /* events are typically 32 bytes */
+	int fd = setup(in, nonblock);
+
+	generate_event(fd);
+	generate_event(fd);
+
+	wait_for_event(fd);
+
+	alarm(3);
+
+	igt_assert_eq(read(fd, buffer, 4), 0);
+	igt_assert(read(fd, buffer, 40) > 0);
+	igt_assert(read(fd, buffer, 40) > 0);
+
+	teardown(fd);
+}
+
+igt_main
+{
+	int fd;
+
+	signal(SIGALRM, sighandler);
+	siginterrupt(SIGALRM, 1);
+
+	igt_fixture {
+		fd = drm_open_any_master();
+	}
+
+	igt_subtest("invalid-buffer")
+		test_invalid_buffer(fd);
+
+	igt_subtest("empty-block")
+		test_empty(fd, 0, EINTR);
+
+	igt_subtest("empty-nonblock")
+		test_empty(fd, 1, EAGAIN);
+
+	igt_subtest("short-buffer-block")
+		test_short_buffer(fd, 0);
+
+	igt_subtest("short-buffer-nonblock")
+		test_short_buffer(fd, 1);
+}