selftests: media_tests add a new video device test

Add a new video device test that opens user specified Video Device and
calls video ioctls in a loop once every 10 seconds.

This test is intended for testing device removal and driver unbind while
an ioctl is active. Clean device removal and driver unbind is expected
without any use-after-free and panics.
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>

tools/testing/selftests/media_tests/.gitignore

 media_device_test
 media_device_open
+video_device_test

tools/testing/selftests/media_tests/Makefile

-TEST_PROGS := media_device_test media_device_open
+TEST_PROGS := media_device_test media_device_open video_device_test
 all: $(TEST_PROGS)
 
 include ../lib.mk
 
 clean:
-	rm -fr media_device_test media_device_open
+	rm -fr media_device_test media_device_open video_device_test

tools/testing/selftests/media_tests/video_device_test.c

+/*
+ * video_device_test - Video Device Test
+ *
+ * Copyright (c) 2016 Shuah Khan <shuahkh@osg.samsung.com>
+ * Copyright (c) 2016 Samsung Electronics Co., Ltd.
+ *
+ * This file is released under the GPLv2.
+ */
+
+/*
+ * This file adds a test for Video Device. This test should not be included
+ * in the Kselftest run. This test should be run when hardware and driver
+ * that makes use of V4L2 API is present.
+ *
+ * This test opens user specified Video Device and calls video ioctls in a
+ * loop once every 10 seconds.
+ *
+ * Usage:
+ *	sudo ./video_device_test -d /dev/videoX
+ *
+ *	While test is running, remove the device or unbind the driver and
+ *	ensure there are no use after free errors and other Oops in the
+ *	dmesg.
+ *	When possible, enable KaSan kernel config option for use-after-free
+ *	error detection.
+*/
+
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <string.h>
+#include <fcntl.h>
+#include <sys/ioctl.h>
+#include <sys/stat.h>
+#include <time.h>
+#include <linux/videodev2.h>
+
+int main(int argc, char **argv)
+{
+	int opt;
+	char video_dev[256];
+	int count;
+	struct v4l2_tuner vtuner;
+	struct v4l2_capability vcap;
+	int ret;
+	int fd;
+
+	if (argc < 2) {
+		printf("Usage: %s [-d </dev/videoX>]\n", argv[0]);
+		exit(-1);
+	}
+
+	/* Process arguments */
+	while ((opt = getopt(argc, argv, "d:")) != -1) {
+		switch (opt) {
+		case 'd':
+			strncpy(video_dev, optarg, sizeof(video_dev) - 1);
+			video_dev[sizeof(video_dev)-1] = '\0';
+			break;
+		default:
+			printf("Usage: %s [-d </dev/videoX>]\n", argv[0]);
+			exit(-1);
+		}
+	}
+
+	/* Generate random number of interations */
+	srand((unsigned int) time(NULL));
+	count = rand();
+
+	/* Open Video device and keep it open */
+	fd = open(video_dev, O_RDWR);
+	if (fd == -1) {
+		printf("Video Device open errno %s\n", strerror(errno));
+		exit(-1);
+	}
+
+	printf("\nNote:\n"
+	       "While test is running, remove the device or unbind\n"
+	       "driver and ensure there are no use after free errors\n"
+	       "and other Oops in the dmesg. When possible, enable KaSan\n"
+	       "kernel config option for use-after-free error detection.\n\n");
+
+	while (count > 0) {
+		ret = ioctl(fd, VIDIOC_QUERYCAP, &vcap);
+		if (ret < 0)
+			printf("VIDIOC_QUERYCAP errno %s\n", strerror(errno));
+		else
+			printf("Video device driver %s\n", vcap.driver);
+
+		ret = ioctl(fd, VIDIOC_G_TUNER, &vtuner);
+		if (ret < 0)
+			printf("VIDIOC_G_TUNER, errno %s\n", strerror(errno));
+		else
+			printf("type %d rangelow %d rangehigh %d\n",
+				vtuner.type, vtuner.rangelow, vtuner.rangehigh);
+		sleep(10);
+		count--;
+	}
+}