Initial import

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diff --git a/samples/uhid/uhid-example.c b/samples/uhid/uhid-example.c
new file mode 100644
index 000000000..7d58a4b8d
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+++ b/samples/uhid/uhid-example.c
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+/*
+ * UHID Example
+ *
+ * Copyright (c) 2012-2013 David Herrmann <dh.herrmann@gmail.com>
+ *
+ * The code may be used by anyone for any purpose,
+ * and can serve as a starting point for developing
+ * applications using uhid.
+ */
+
+/*
+ * UHID Example
+ * This example emulates a basic 3 buttons mouse with wheel over UHID. Run this
+ * program as root and then use the following keys to control the mouse:
+ *   q: Quit the application
+ *   1: Toggle left button (down, up, ...)
+ *   2: Toggle right button
+ *   3: Toggle middle button
+ *   a: Move mouse left
+ *   d: Move mouse right
+ *   w: Move mouse up
+ *   s: Move mouse down
+ *   r: Move wheel up
+ *   f: Move wheel down
+ *
+ * Additionally to 3 button mouse, 3 keyboard LEDs are also supported (LED_NUML,
+ * LED_CAPSL and LED_SCROLLL). The device doesn't generate any related keyboard
+ * events, though. You need to manually write the EV_LED/LED_XY/1 activation
+ * input event to the evdev device to see it being sent to this device.
+ *
+ * If uhid is not available as /dev/uhid, then you can pass a different path as
+ * first argument.
+ * If <linux/uhid.h> is not installed in /usr, then compile this with:
+ *   gcc -o ./uhid_test -Wall -I./include ./samples/uhid/uhid-example.c
+ * And ignore the warning about kernel headers. However, it is recommended to
+ * use the installed uhid.h if available.
+ */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <poll.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <termios.h>
+#include <unistd.h>
+#include <linux/uhid.h>
+
+/*
+ * HID Report Desciptor
+ * We emulate a basic 3 button mouse with wheel and 3 keyboard LEDs. This is
+ * the report-descriptor as the kernel will parse it:
+ *
+ * INPUT(1)[INPUT]
+ *   Field(0)
+ *     Physical(GenericDesktop.Pointer)
+ *     Application(GenericDesktop.Mouse)
+ *     Usage(3)
+ *       Button.0001
+ *       Button.0002
+ *       Button.0003
+ *     Logical Minimum(0)
+ *     Logical Maximum(1)
+ *     Report Size(1)
+ *     Report Count(3)
+ *     Report Offset(0)
+ *     Flags( Variable Absolute )
+ *   Field(1)
+ *     Physical(GenericDesktop.Pointer)
+ *     Application(GenericDesktop.Mouse)
+ *     Usage(3)
+ *       GenericDesktop.X
+ *       GenericDesktop.Y
+ *       GenericDesktop.Wheel
+ *     Logical Minimum(-128)
+ *     Logical Maximum(127)
+ *     Report Size(8)
+ *     Report Count(3)
+ *     Report Offset(8)
+ *     Flags( Variable Relative )
+ * OUTPUT(2)[OUTPUT]
+ *   Field(0)
+ *     Application(GenericDesktop.Keyboard)
+ *     Usage(3)
+ *       LED.NumLock
+ *       LED.CapsLock
+ *       LED.ScrollLock
+ *     Logical Minimum(0)
+ *     Logical Maximum(1)
+ *     Report Size(1)
+ *     Report Count(3)
+ *     Report Offset(0)
+ *     Flags( Variable Absolute )
+ *
+ * This is the mapping that we expect:
+ *   Button.0001 ---> Key.LeftBtn
+ *   Button.0002 ---> Key.RightBtn
+ *   Button.0003 ---> Key.MiddleBtn
+ *   GenericDesktop.X ---> Relative.X
+ *   GenericDesktop.Y ---> Relative.Y
+ *   GenericDesktop.Wheel ---> Relative.Wheel
+ *   LED.NumLock ---> LED.NumLock
+ *   LED.CapsLock ---> LED.CapsLock
+ *   LED.ScrollLock ---> LED.ScrollLock
+ *
+ * This information can be verified by reading /sys/kernel/debug/hid/<dev>/rdesc
+ * This file should print the same information as showed above.
+ */
+
+static unsigned char rdesc[] = {
+	0x05, 0x01,	/* USAGE_PAGE (Generic Desktop) */
+	0x09, 0x02,	/* USAGE (Mouse) */
+	0xa1, 0x01,	/* COLLECTION (Application) */
+	0x09, 0x01,		/* USAGE (Pointer) */
+	0xa1, 0x00,		/* COLLECTION (Physical) */
+	0x85, 0x01,			/* REPORT_ID (1) */
+	0x05, 0x09,			/* USAGE_PAGE (Button) */
+	0x19, 0x01,			/* USAGE_MINIMUM (Button 1) */
+	0x29, 0x03,			/* USAGE_MAXIMUM (Button 3) */
+	0x15, 0x00,			/* LOGICAL_MINIMUM (0) */
+	0x25, 0x01,			/* LOGICAL_MAXIMUM (1) */
+	0x95, 0x03,			/* REPORT_COUNT (3) */
+	0x75, 0x01,			/* REPORT_SIZE (1) */
+	0x81, 0x02,			/* INPUT (Data,Var,Abs) */
+	0x95, 0x01,			/* REPORT_COUNT (1) */
+	0x75, 0x05,			/* REPORT_SIZE (5) */
+	0x81, 0x01,			/* INPUT (Cnst,Var,Abs) */
+	0x05, 0x01,			/* USAGE_PAGE (Generic Desktop) */
+	0x09, 0x30,			/* USAGE (X) */
+	0x09, 0x31,			/* USAGE (Y) */
+	0x09, 0x38,			/* USAGE (WHEEL) */
+	0x15, 0x81,			/* LOGICAL_MINIMUM (-127) */
+	0x25, 0x7f,			/* LOGICAL_MAXIMUM (127) */
+	0x75, 0x08,			/* REPORT_SIZE (8) */
+	0x95, 0x03,			/* REPORT_COUNT (3) */
+	0x81, 0x06,			/* INPUT (Data,Var,Rel) */
+	0xc0,			/* END_COLLECTION */
+	0xc0,		/* END_COLLECTION */
+	0x05, 0x01,	/* USAGE_PAGE (Generic Desktop) */
+	0x09, 0x06,	/* USAGE (Keyboard) */
+	0xa1, 0x01,	/* COLLECTION (Application) */
+	0x85, 0x02,		/* REPORT_ID (2) */
+	0x05, 0x08,		/* USAGE_PAGE (Led) */
+	0x19, 0x01,		/* USAGE_MINIMUM (1) */
+	0x29, 0x03,		/* USAGE_MAXIMUM (3) */
+	0x15, 0x00,		/* LOGICAL_MINIMUM (0) */
+	0x25, 0x01,		/* LOGICAL_MAXIMUM (1) */
+	0x95, 0x03,		/* REPORT_COUNT (3) */
+	0x75, 0x01,		/* REPORT_SIZE (1) */
+	0x91, 0x02,		/* Output (Data,Var,Abs) */
+	0x95, 0x01,		/* REPORT_COUNT (1) */
+	0x75, 0x05,		/* REPORT_SIZE (5) */
+	0x91, 0x01,		/* Output (Cnst,Var,Abs) */
+	0xc0,		/* END_COLLECTION */
+};
+
+static int uhid_write(int fd, const struct uhid_event *ev)
+{
+	ssize_t ret;
+
+	ret = write(fd, ev, sizeof(*ev));
+	if (ret < 0) {
+		fprintf(stderr, "Cannot write to uhid: %m\n");
+		return -errno;
+	} else if (ret != sizeof(*ev)) {
+		fprintf(stderr, "Wrong size written to uhid: %ld != %lu\n",
+			ret, sizeof(ev));
+		return -EFAULT;
+	} else {
+		return 0;
+	}
+}
+
+static int create(int fd)
+{
+	struct uhid_event ev;
+
+	memset(&ev, 0, sizeof(ev));
+	ev.type = UHID_CREATE;
+	strcpy((char*)ev.u.create.name, "test-uhid-device");
+	ev.u.create.rd_data = rdesc;
+	ev.u.create.rd_size = sizeof(rdesc);
+	ev.u.create.bus = BUS_USB;
+	ev.u.create.vendor = 0x15d9;
+	ev.u.create.product = 0x0a37;
+	ev.u.create.version = 0;
+	ev.u.create.country = 0;
+
+	return uhid_write(fd, &ev);
+}
+
+static void destroy(int fd)
+{
+	struct uhid_event ev;
+
+	memset(&ev, 0, sizeof(ev));
+	ev.type = UHID_DESTROY;
+
+	uhid_write(fd, &ev);
+}
+
+/* This parses raw output reports sent by the kernel to the device. A normal
+ * uhid program shouldn't do this but instead just forward the raw report.
+ * However, for ducomentational purposes, we try to detect LED events here and
+ * print debug messages for it. */
+static void handle_output(struct uhid_event *ev)
+{
+	/* LED messages are adverised via OUTPUT reports; ignore the rest */
+	if (ev->u.output.rtype != UHID_OUTPUT_REPORT)
+		return;
+	/* LED reports have length 2 bytes */
+	if (ev->u.output.size != 2)
+		return;
+	/* first byte is report-id which is 0x02 for LEDs in our rdesc */
+	if (ev->u.output.data[0] != 0x2)
+		return;
+
+	/* print flags payload */
+	fprintf(stderr, "LED output report received with flags %x\n",
+		ev->u.output.data[1]);
+}
+
+static int event(int fd)
+{
+	struct uhid_event ev;
+	ssize_t ret;
+
+	memset(&ev, 0, sizeof(ev));
+	ret = read(fd, &ev, sizeof(ev));
+	if (ret == 0) {
+		fprintf(stderr, "Read HUP on uhid-cdev\n");
+		return -EFAULT;
+	} else if (ret < 0) {
+		fprintf(stderr, "Cannot read uhid-cdev: %m\n");
+		return -errno;
+	} else if (ret != sizeof(ev)) {
+		fprintf(stderr, "Invalid size read from uhid-dev: %ld != %lu\n",
+			ret, sizeof(ev));
+		return -EFAULT;
+	}
+
+	switch (ev.type) {
+	case UHID_START:
+		fprintf(stderr, "UHID_START from uhid-dev\n");
+		break;
+	case UHID_STOP:
+		fprintf(stderr, "UHID_STOP from uhid-dev\n");
+		break;
+	case UHID_OPEN:
+		fprintf(stderr, "UHID_OPEN from uhid-dev\n");
+		break;
+	case UHID_CLOSE:
+		fprintf(stderr, "UHID_CLOSE from uhid-dev\n");
+		break;
+	case UHID_OUTPUT:
+		fprintf(stderr, "UHID_OUTPUT from uhid-dev\n");
+		handle_output(&ev);
+		break;
+	case UHID_OUTPUT_EV:
+		fprintf(stderr, "UHID_OUTPUT_EV from uhid-dev\n");
+		break;
+	default:
+		fprintf(stderr, "Invalid event from uhid-dev: %u\n", ev.type);
+	}
+
+	return 0;
+}
+
+static bool btn1_down;
+static bool btn2_down;
+static bool btn3_down;
+static signed char abs_hor;
+static signed char abs_ver;
+static signed char wheel;
+
+static int send_event(int fd)
+{
+	struct uhid_event ev;
+
+	memset(&ev, 0, sizeof(ev));
+	ev.type = UHID_INPUT;
+	ev.u.input.size = 5;
+
+	ev.u.input.data[0] = 0x1;
+	if (btn1_down)
+		ev.u.input.data[1] |= 0x1;
+	if (btn2_down)
+		ev.u.input.data[1] |= 0x2;
+	if (btn3_down)
+		ev.u.input.data[1] |= 0x4;
+
+	ev.u.input.data[2] = abs_hor;
+	ev.u.input.data[3] = abs_ver;
+	ev.u.input.data[4] = wheel;
+
+	return uhid_write(fd, &ev);
+}
+
+static int keyboard(int fd)
+{
+	char buf[128];
+	ssize_t ret, i;
+
+	ret = read(STDIN_FILENO, buf, sizeof(buf));
+	if (ret == 0) {
+		fprintf(stderr, "Read HUP on stdin\n");
+		return -EFAULT;
+	} else if (ret < 0) {
+		fprintf(stderr, "Cannot read stdin: %m\n");
+		return -errno;
+	}
+
+	for (i = 0; i < ret; ++i) {
+		switch (buf[i]) {
+		case '1':
+			btn1_down = !btn1_down;
+			ret = send_event(fd);
+			if (ret)
+				return ret;
+			break;
+		case '2':
+			btn2_down = !btn2_down;
+			ret = send_event(fd);
+			if (ret)
+				return ret;
+			break;
+		case '3':
+			btn3_down = !btn3_down;
+			ret = send_event(fd);
+			if (ret)
+				return ret;
+			break;
+		case 'a':
+			abs_hor = -20;
+			ret = send_event(fd);
+			abs_hor = 0;
+			if (ret)
+				return ret;
+			break;
+		case 'd':
+			abs_hor = 20;
+			ret = send_event(fd);
+			abs_hor = 0;
+			if (ret)
+				return ret;
+			break;
+		case 'w':
+			abs_ver = -20;
+			ret = send_event(fd);
+			abs_ver = 0;
+			if (ret)
+				return ret;
+			break;
+		case 's':
+			abs_ver = 20;
+			ret = send_event(fd);
+			abs_ver = 0;
+			if (ret)
+				return ret;
+			break;
+		case 'r':
+			wheel = 1;
+			ret = send_event(fd);
+			wheel = 0;
+			if (ret)
+				return ret;
+			break;
+		case 'f':
+			wheel = -1;
+			ret = send_event(fd);
+			wheel = 0;
+			if (ret)
+				return ret;
+			break;
+		case 'q':
+			return -ECANCELED;
+		default:
+			fprintf(stderr, "Invalid input: %c\n", buf[i]);
+		}
+	}
+
+	return 0;
+}
+
+int main(int argc, char **argv)
+{
+	int fd;
+	const char *path = "/dev/uhid";
+	struct pollfd pfds[2];
+	int ret;
+	struct termios state;
+
+	ret = tcgetattr(STDIN_FILENO, &state);
+	if (ret) {
+		fprintf(stderr, "Cannot get tty state\n");
+	} else {
+		state.c_lflag &= ~ICANON;
+		state.c_cc[VMIN] = 1;
+		ret = tcsetattr(STDIN_FILENO, TCSANOW, &state);
+		if (ret)
+			fprintf(stderr, "Cannot set tty state\n");
+	}
+
+	if (argc >= 2) {
+		if (!strcmp(argv[1], "-h") || !strcmp(argv[1], "--help")) {
+			fprintf(stderr, "Usage: %s [%s]\n", argv[0], path);
+			return EXIT_SUCCESS;
+		} else {
+			path = argv[1];
+		}
+	}
+
+	fprintf(stderr, "Open uhid-cdev %s\n", path);
+	fd = open(path, O_RDWR | O_CLOEXEC);
+	if (fd < 0) {
+		fprintf(stderr, "Cannot open uhid-cdev %s: %m\n", path);
+		return EXIT_FAILURE;
+	}
+
+	fprintf(stderr, "Create uhid device\n");
+	ret = create(fd);
+	if (ret) {
+		close(fd);
+		return EXIT_FAILURE;
+	}
+
+	pfds[0].fd = STDIN_FILENO;
+	pfds[0].events = POLLIN;
+	pfds[1].fd = fd;
+	pfds[1].events = POLLIN;
+
+	fprintf(stderr, "Press 'q' to quit...\n");
+	while (1) {
+		ret = poll(pfds, 2, -1);
+		if (ret < 0) {
+			fprintf(stderr, "Cannot poll for fds: %m\n");
+			break;
+		}
+		if (pfds[0].revents & POLLHUP) {
+			fprintf(stderr, "Received HUP on stdin\n");
+			break;
+		}
+		if (pfds[1].revents & POLLHUP) {
+			fprintf(stderr, "Received HUP on uhid-cdev\n");
+			break;
+		}
+
+		if (pfds[0].revents & POLLIN) {
+			ret = keyboard(fd);
+			if (ret)
+				break;
+		}
+		if (pfds[1].revents & POLLIN) {
+			ret = event(fd);
+			if (ret)
+				break;
+		}
+	}
+
+	fprintf(stderr, "Destroy uhid device\n");
+	destroy(fd);
+	return EXIT_SUCCESS;
+}