Question

我正在尝试使用绝对坐标移动光标。这是代码：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <linux/input.h>
#include <linux/uinput.h>
#include <signal.h>

#define die(str, args...) do { \
        perror(str); \
        exit(EXIT_FAILURE); \
    } while(0)

    int                    fd;

static void signal_handler(int signo)
{
    printf("\nCaught SIGINT\n");
        if(ioctl(fd, UI_DEV_DESTROY) < 0)
           die("error: cannot destroy uinput device\n");
    else printf("Destroyed uinput_user_dev\n\n");
    close(fd);
    exit(EXIT_SUCCESS);
}

int
main(void)
{

    struct uinput_user_dev uidev;
    struct input_event     ev;
    int                    x, y;
    int                    i;

    if(signal(SIGINT,signal_handler)==SIG_ERR)
    {
    printf("error registering signal handler\n");
    exit(EXIT_FAILURE);

    }

    fd = open("/dev/uinput", O_WRONLY | O_NONBLOCK);
    if(fd < 0)
        die("error: open");

    if(ioctl(fd, UI_SET_EVBIT, EV_KEY) < 0)
        die("error: ioctl");
   // if(ioctl(fd, UI_SET_KEYBIT, BTN_MOUSE) < 0)
    //    die("error: ioctl");
    if(ioctl(fd, UI_SET_KEYBIT, BTN_LEFT) < 0)
        die("error: ioctl");
    if(ioctl(fd, UI_SET_KEYBIT, BTN_RIGHT) < 0)
        die("error: ioctl");

   if(ioctl(fd, UI_SET_EVBIT, EV_REL) < 0)
        die("error: ioctl");
    if(ioctl(fd, UI_SET_RELBIT, REL_X) < 0)
        die("error: ioctl");
    if(ioctl(fd, UI_SET_RELBIT, REL_Y) < 0)
        die("error: ioctl");

    if(ioctl(fd, UI_SET_EVBIT, EV_ABS) < 0)       
        die("error: ioctl");
    if(ioctl(fd, UI_SET_ABSBIT,ABS_X) < 0)
        die("error: ioctl");
    if(ioctl(fd, UI_SET_ABSBIT, ABS_Y) < 0)
        die("error: ioctl");

    memset(&uidev, 0, sizeof(uidev));
    snprintf(uidev.name, UINPUT_MAX_NAME_SIZE, "uinput-sample");
    uidev.id.bustype = BUS_USB;
    uidev.id.vendor  = 0x1;
    uidev.id.product = 0x1;
    uidev.id.version = 1;

    uidev.absmin[ABS_X]=0;
    uidev.absmax[ABS_X]=1023;
    uidev.absfuzz[ABS_X]=0;
    uidev.absflat[ABS_X ]=0;
    uidev.absmin[ABS_Y]=0;
    uidev.absmax[ABS_Y]=767;
    uidev.absfuzz[ABS_Y]=0;
    uidev.absflat[ABS_Y ]=0;

    if(write(fd, &uidev, sizeof(uidev)) < 0)
        die("error: write0");

    if(ioctl(fd, UI_DEV_CREATE) < 0)
        die("error: ioctl");

    sleep(2);
    while(1)
    {

       printf("\nEnter the absoulte x(0-1023) and y(0-767) co-ordinates:");
           scanf("%d %d",&x,&y);       
           memset(&ev, 0, sizeof(struct input_event));
       gettimeofday(&ev.time,NULL);
           ev.type = EV_ABS;
           ev.code = ABS_X;
           ev.value = x;
           if(write(fd, &ev, sizeof(struct input_event)) < 0)
                die("error: write1");

       memset(&ev, 0, sizeof(struct input_event));
           ev.type = EV_SYN;
           if(write(fd, &ev, sizeof(struct input_event)) < 0)
                die("error: write4");

           memset(&ev, 0, sizeof(struct input_event));
           ev.type = EV_ABS;
           ev.code = ABS_Y;
           ev.value = y;
           if(write(fd, &ev, sizeof(struct input_event)) < 0)
                die("error: write2");
           memset(&ev, 0, sizeof(struct input_event));
           ev.type = EV_SYN;
           if(write(fd, &ev, sizeof(struct input_event)) < 0)
                die("error: write3");
       usleep(15000);
       printf("\nWritten x:%d y:%d to uinput.Press CTRL-C to quit:",x,y);


    }

        if(ioctl(fd, UI_DEV_DESTROY) < 0)
           die("error: cannot destroy uinput device\n");
        close(fd);

    return 0;
}

该程序似乎通过uinput将我输入的绝对坐标发送到内核的输入核心。

我在启用evbug后在dmesg上验证了这一点。但我的鼠标指针不会在屏幕上移动。我想知道我搞砸了什么。

也许EV_ABS没有绑定光标？我想知道，因为使用EV_REL移动光标的工作正常，如this tutorial中所述。

示例运行

ravi@linux-lxaf:~/workspace/driver> sudo ./a.out 

Enter the absoulte x(0-1023) and y(0-767) co-ordinates:100 200

Written x:100 y:200 to uinput.Press CTRL-C to quit:
Enter the absoulte x(0-1023) and y(0-767) co-ordinates:10 765

Written x:10 y:765 to uinput.Press CTRL-C to quit:
Enter the absoulte x(0-1023) and y(0-767) co-ordinates:^C
Caught SIGINT
Destroyed uinput_user_dev

Dmesg输出：

ravi@linux-lxaf:~/workspace/driver> dmesg |grep input16
[ 4750.660420] input: uinput-sample as /devices/virtual/input/input16
[ 4750.660594] evbug.c: Connected device: input16 (uinput-sample at unknown)
[ 4761.389036] evbug.c: Event. Dev: input16, Type: 3, Code: 0, Value: 100
[ 4761.389047] evbug.c: Event. Dev: input16, Type: 0, Code: 0, Value: 0
[ 4761.389053] evbug.c: Event. Dev: input16, Type: 3, Code: 1, Value: 200
[ 4761.389058] evbug.c: Event. Dev: input16, Type: 0, Code: 0, Value: 0
[ 4776.893126] evbug.c: Event. Dev: input16, Type: 3, Code: 0, Value: 10
[ 4776.893138] evbug.c: Event. Dev: input16, Type: 0, Code: 0, Value: 0
[ 4776.893144] evbug.c: Event. Dev: input16, Type: 3, Code: 1, Value: 765
[ 4776.893148] evbug.c: Event. Dev: input16, Type: 0, Code: 0, Value: 0
[ 4778.729711] evbug.c: Event. Dev: input16, Type: 0, Code: 0, Value: 1
[ 4778.745506] evbug.c: Disconnected device: input16

Answer 1

我刚刚发现输入内核将EV_ABS值作为绝对值传播到设备节点，如从/ dev / input / eventX中看到的那样（似乎很明显现在！）。沿着，控制光标的应用程序（X11？）期待相对鼠标移动，而我给它绝对值，这可能会让它感到困惑！

使用uinput模拟Linux中的绝对鼠标移动

1 个答案: