os: Add a minimal hidraw wrapper

src/xrt/auxiliary/CMakeLists.txt

@@ -10,6 +10,12 @@ set(MATH_SOURCE_FILES
 	math/m_quatexpmap.cpp
 	)
 
+set(OS_SOURCE_FILES
+	os/os_documentation.h
+	os/os_hid.h
+	os/os_hid_hidraw.c
+	)
+
 set(UTIL_SOURCE_FILES
 	util/u_misc.c
 	util/u_misc.h
@@ -35,6 +41,10 @@ include_directories(
 add_library(aux_util OBJECT ${UTIL_SOURCE_FILES})
 set_property(TARGET aux_util PROPERTY POSITION_INDEPENDENT_CODE ON)
 
+# OS library.
+add_library(aux_os OBJECT ${OS_SOURCE_FILES})
+set_property(TARGET aux_os PROPERTY POSITION_INDEPENDENT_CODE ON)
+
 # Math library.
 # Use OBJECT to not create a archive, since it just gets in the way.
 add_library(aux_math OBJECT ${MATH_SOURCE_FILES})

src/xrt/auxiliary/os/os_documentation.h

@@ -0,0 +1,25 @@
+// Copyright 2019, Collabora, Ltd.
+// SPDX-License-Identifier: BSL-1.0
+/*!
+ * @file
+ * @brief  Documentation.
+ * @author Jakob Bornecrantz <jakob@collabora.com>
+ * @ingroup aux_os
+ */
+
+#pragma once
+
+
+/*!
+ * @defgroup aux_os OS-Wrappers
+ * @ingroup aux
+ *
+ * @brief Wrapper around OS functions and structs.
+ */
+
+/*!
+ * @dir auxiliary/os
+ * @ingroup aux
+ *
+ * @brief Wrapper around OS functions and structs.
+ */

src/xrt/auxiliary/os/os_hid.h

@@ -0,0 +1,71 @@
+// Copyright 2019, Collabora, Ltd.
+// SPDX-License-Identifier: BSL-1.0
+/*!
+ * @file
+ * @brief  Wrapper around OS native hid functions.
+ * @author Jakob Bornecrantz <jakob@collabora.com>
+ *
+ * @ingroup aux_os
+ */
+
+#pragma once
+
+#include "xrt/xrt_config.h"
+#include "xrt/xrt_compiler.h"
+
+
+/*!
+ * Representing a single hid interface on a device.
+ */
+struct os_hid_device
+{
+	int (*read)(struct os_hid_device *hid_dev,
+	            uint8_t *data,
+	            size_t size,
+	            int milliseconds);
+
+	int (*write)(struct os_hid_device *hid_dev,
+	             const uint8_t *data,
+	             size_t size);
+
+	void (*destroy)(struct os_hid_device *hid_dev);
+};
+
+/*!
+ * Read from the given hid device, if milliseconds are negative blocks, 0 polls
+ * and positive will block for that amount of seconds.
+ */
+XRT_MAYBE_UNUSED static inline int
+os_hid_read(struct os_hid_device *hid_dev,
+            uint8_t *data,
+            size_t size,
+            int milliseconds)
+{
+	return hid_dev->read(hid_dev, data, size, milliseconds);
+}
+
+/*!
+ * Write to the given device.
+ */
+XRT_MAYBE_UNUSED static inline int
+os_hid_write(struct os_hid_device *hid_dev, const uint8_t *data, size_t size)
+{
+	return hid_dev->write(hid_dev, data, size);
+}
+
+/*!
+ * Close and free the given device.
+ */
+XRT_MAYBE_UNUSED static inline void
+os_hid_destroy(struct os_hid_device *hid_dev)
+{
+	hid_dev->destroy(hid_dev);
+}
+
+#ifdef XRT_OS_LINUX
+/*!
+ * Open the given path as a hidraw device.
+ */
+int
+os_hid_open_hidraw(const char *path, struct os_hid_device **out_hid);
+#endif

src/xrt/auxiliary/os/os_hid_hidraw.c

@@ -0,0 +1,106 @@
+// Copyright 2019, Collabora, Ltd.
+// SPDX-License-Identifier: BSL-1.0
+/*!
+ * @file
+ * @brief  Hid implementation based on hidraw.
+ * @author Jakob Bornecrantz <jakob@collabora.com>
+ * @ingroup aux_os
+ */
+
+#include "os_hid.h"
+
+#ifdef XRT_OS_LINUX
+
+#include "util/u_misc.h"
+#include <poll.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <string.h>
+
+#include <sys/ioctl.h>
+
+#include <linux/hidraw.h>
+
+
+#include <stdio.h>
+
+struct hid_hidraw
+{
+	struct os_hid_device base;
+
+	int fd;
+};
+
+static int
+os_hidraw_read(struct os_hid_device *ohdev,
+               uint8_t *data,
+               size_t length,
+               int milliseconds)
+{
+	struct hid_hidraw *hrdev = (struct hid_hidraw *)ohdev;
+	struct pollfd fds;
+	int ret;
+
+	if (milliseconds >= 0) {
+		fds.fd = hrdev->fd;
+		fds.events = POLLIN;
+		fds.revents = 0;
+		ret = poll(&fds, 1, milliseconds);
+
+		if (ret == -1 || ret == 0) {
+			// Error or timeout.
+			return ret;
+		} else if (fds.revents & (POLLERR | POLLHUP | POLLNVAL)) {
+			// Device disconnect?
+			return -1;
+		}
+	}
+
+	ret = read(hrdev->fd, data, length);
+
+	if (ret < 0 && (errno == EAGAIN || errno == EINPROGRESS)) {
+		// Process most likely received a signal.
+		ret = 0;
+	}
+
+	return ret;
+}
+
+static int
+os_hidraw_write(struct os_hid_device *ohdev, const uint8_t *data, size_t length)
+{
+	struct hid_hidraw *hrdev = (struct hid_hidraw *)ohdev;
+
+	return write(hrdev->fd, data, length);
+}
+
+static void
+os_hidraw_destroy(struct os_hid_device *ohdev)
+{
+	struct hid_hidraw *hrdev = (struct hid_hidraw *)ohdev;
+
+	close(hrdev->fd);
+	free(hrdev);
+}
+
+int
+os_hid_open_hidraw(const char *path, struct os_hid_device **out_ohdev)
+{
+	struct hid_hidraw *hrdev = U_TYPED_CALLOC(struct hid_hidraw);
+
+	hrdev->base.read = os_hidraw_read;
+	hrdev->base.write = os_hidraw_write;
+	hrdev->base.destroy = os_hidraw_destroy;
+	hrdev->fd = open(path, O_RDWR);
+	if (hrdev->fd < 0) {
+		free(hrdev);
+		return -1;
+	}
+
+	*out_ohdev = &hrdev->base;
+
+	return 0;
+}
+
+#endif

src/xrt/targets/openxr/CMakeLists.txt

@@ -61,6 +61,7 @@ add_library(${RUNTIME_TARGET} SHARED
 	${MANIFEST_DEV_PATH}
 	${MANIFEST_PATH}
 	${SOURCE_FILES}
+	$<TARGET_OBJECTS:aux_os>
 	$<TARGET_OBJECTS:aux_util>
 	$<TARGET_OBJECTS:aux_math>
 	$<TARGET_OBJECTS:comp>