创建linux虚拟键盘设备

sudo apt-get update
sudo apt-get install build-essential libudev-dev

git clone https://github.com/torvalds/linux.git
cd linux/drivers/input/uinput

make -C /lib/modules/$(uname -r)/build M=$(pwd) modules

sudo make -C /lib/modules/$(uname -r)/build M=$(pwd) modules_install

sudo modprobe uinput

#include <linux/uinput.h>
#include <fcntl.h>
#include <unistd.h>

int main() {
    int fd = open("/dev/uinput", O_WRONLY | O_NONBLOCK);
    if(fd < 0) {
        perror("open");
        return -1;
    }

    struct uinput_user_dev uidev;
    memset(&uidev, 0, sizeof(uidev));
    snprintf(uidev.name, UINPUT_MAX_NAME_SIZE, "Virtual Keyboard");
    uidev.id.bustype = BUS_USB;
    uidev.id.vendor = 0x1;
    uidev.id.product = 0x1;
    uidev.id.version = 1;

    // 设置按键
    ioctl(fd, UI_SET_KEYBIT, KEY_A);
    ioctl(fd, UI_SET_KEYBIT, KEY_B);
    ioctl(fd, UI_SET_KEYBIT, KEY_C);

    write(fd, &uidev, sizeof(uidev));
    ioctl(fd, UI_DEV_CREATE);

    // 发送按键事件
    struct input_event ev;
    memset(&ev, 0, sizeof(ev));
    ev.type = EV_KEY;
    ev.code = KEY_A;
    ev.value = 1; // 按下
    write(fd, &ev, sizeof(ev));

    ev.value = 0; // 释放
    write(fd, &ev, sizeof(ev));

    sleep(1);

    ioctl(fd, UI_DEV_DESTROY);
    close(fd);

    return 0;
}

gcc -o virtual_keyboard virtual_keyboard.c
sudo ./virtual_keyboard