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Diffstat (limited to 'samples/uhid/uhid-example.c')
| -rw-r--r-- | samples/uhid/uhid-example.c | 465 |
1 files changed, 465 insertions, 0 deletions
diff --git a/samples/uhid/uhid-example.c b/samples/uhid/uhid-example.c new file mode 100644 index 000000000..015cb06a2 --- /dev/null +++ b/samples/uhid/uhid-example.c @@ -0,0 +1,465 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * 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: %zd != %zu\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: %zd != %zu\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; +} |