Mouse emulator @ Linux

底下是 In-Air Mouse and Joystick 的 Demo,利用 Remote control 來模擬真實 mouse 的情形.想說不如來找找有沒有source code 可以研究.沒想到居然還有個叫 Keymouse 的 project,喝喝...看來google 真是太神了. 1.先用 modprobe 掛載 devices到 /dev/input上,

% sudo modprobe uinput

2. sample code ref here 確定uinput掛載好後,用ioctl()來控制IO2的讀寫.最後用linux/input.h 中的 input_event來模擬我們 input的vector.

#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <linux/input.h>
#include <linux/uinput.h>
#include <sys/time.h>
#include <unistd.h>

// Test the uinput module

struct uinput_user_dev   uinp;
struct input_event       event;

int main(void) {

            int ufile, retcode, i;

            ufile = open("/dev/input/uinput", O_WRONLY | O_NDELAY );
            printf("open /dev/input/uinput returned %d.\n", ufile);
            if (ufile == 0) {
                        printf("Could not open uinput.\n");
                        return -1;
            }

            memset(&uinp, 0, sizeof(uinp));
            strncpy(uinp.name, "simulated mouse", 20);
            uinp.id.version = 4;
            uinp.id.bustype = BUS_USB;

            ioctl(ufile, UI_SET_EVBIT, EV_KEY);
            ioctl(ufile, UI_SET_EVBIT, EV_REL);
            ioctl(ufile, UI_SET_RELBIT, REL_X);
            ioctl(ufile, UI_SET_RELBIT, REL_Y);

            for (i=0; i<256; i++) {
                        ioctl(ufile, UI_SET_KEYBIT, i);
            }

            ioctl(ufile, UI_SET_KEYBIT, BTN_MOUSE);

            // create input device in input subsystem
            retcode = write(ufile, &uinp, sizeof(uinp));
            printf("First write returned %d.\n", retcode);

            retcode = (ioctl(ufile, UI_DEV_CREATE));
            printf("ioctl UI_DEV_CREATE returned %d.\n", retcode);
            if (retcode) {
                        printf("Error create uinput device %d.\n", retcode);
                        return -1;
            }

            // NOW DO STUFF !!!!

            for (i=0; i<100; i++) {

                        struct timeval tv1;

                        // move pointer upleft by 5 pixels
                        memset(&event, 0, sizeof(event));
                        gettimeofday(&event.time, NULL);
                        event.type = EV_REL;
                        event.code = REL_X;
                        event.value = -5;
                        write(ufile, &event, sizeof(event));
            
                        memset(&event, 0, sizeof(event));
                        gettimeofday(&event.time, NULL);
                        event.type = EV_REL;
                        event.code = REL_Y;
                        event.value = -5;
                        write(ufile, &event, sizeof(event));
            
                        memset(&event, 0, sizeof(event));
                        gettimeofday(&event.time, NULL);
                        event.type = EV_SYN;
                        event.code = SYN_REPORT;
                        event.value = 0;
                        write(ufile, &event, sizeof(event));

                        // wait just a moment
                        do { gettimeofday(&tv1, NULL); } while ((tv1.tv_usec & 
0x3FFF) != 0);
                        do { gettimeofday(&tv1, NULL); } while ((tv1.tv_usec & 
0x3FFF) == 0);
            }

            // destroy the device
            ioctl(ufile, UI_DEV_DESTROY);

            close(ufile);

}

ps: Keymouse 也是用此原理來做的, 你可以在 device.cpp 發現相似的地方. Refs: Sending simulated mouse events using uinput Mouseemu / uinput Linux Cross Reference Linux 驅動程式的 I/O, #4: fops->ioctl 實作