linux 设备输入子系统---源代码示例自动捕获键盘鼠标等外设消息.docx

Linux input 子系统详解与代码示例李邦柱于杭州2014/01/09Email:由于linux 的驱动模型增加了input层，导致几乎所有的底层驱动都把数据封装在event里上报给input子系统。由此看来，这种改变让kernel 更具有模块化，各个模块的耦合度更低了。下面我们一起来研究input 层_1. 从用户层的角度看input（event 事件）了解linux的人一定会对/dev,/ sys, /proc这几个目录有所印象，这是从内核导出到用户层的接口(从这里几乎可以观览内核)。kernel为我们导出了input在用户态的接口,就是/dev/input/下的接口，所以我们只关注这个目录下的event*(event0/event1/)字符设备。那么这些event*是干什么用的？简单来说就是我们对计算机的输入(包括敲击键盘，移动鼠标等等操作)经过内核(底层驱动,input)处理最后就上报到这些event*里面了。而这里event0,event1,.就是用来区分各个外设的，可以通过命令来查看外设具体和哪个event相关联： 这个命令是：cat /proc/bus/input/devices所以我们用此命令在linux系统查看外设信息。2. 在linux/input.h中有这些数据的结构： struct input_event struct timeval time;/事件发生的时间 _u16 type;/事件类类型：按键和移动鼠标就是不同类型 _u16 code; _s32 value;/事件值：按键和按键就对应不同值;code：事件的代码.如果事件的类型代码是EV_KEY,该代码code为设备键盘代码.代码植0127为键盘上的按键代码,0x1100x116 为鼠标上按键代码,其中0x110(BTN_ LEFT)为鼠标左键,0x111(BTN_RIGHT)为鼠标右键,0x112(BTN_ MIDDLE)为鼠标中键.其它代码含义请参看include/linux/input.h文件. 如果事件的类型代码是EV_REL,code值表示轨迹的类型.如指示鼠标的X轴方向REL_X(代码为0x00),指示鼠标的Y轴方向REL_Y(代码 为0x01),指示鼠标中轮子方向REL_WHEEL(代码为0x08).type:EV_KEY,键盘EV_REL,相对坐标EV_ABS,绝对坐标value：事件的值.如果事件的类型代码是EV_KEY,当按键按下时值为1,松开时值为0;如果事件的类型代码是EV_ REL,value的正数值和负数值分别代表两个不同方向的值./* Event types*/#define EV_SYN 0x00#define EV_KEY 0x01 /按键#define EV_REL 0x02 /相对坐标(轨迹球)#define EV_ABS 0x03 /绝对坐标#define EV_MSC 0x04 /其他#define EV_SW 0x05#define EV_LED 0x11 /LED#define EV_SND 0x12/声音#define EV_REP 0x14/repeat#define EV_FF 0x15#define EV_PWR 0x16#define EV_FF_STATUS 0x17#define EV_MAX 0x1f#define EV_CNT (EV_MAX+1)这里事件指的是我们对外设的操作，比如按键一次可能就产生数个input_event数据3代码示例： 此代码可以完全正确编译运行。把此代码拷贝到xx.c 文件中，gcc xx.c o xx 后要用sudo 去执行。 Sudo ./xx此程序的功能是可以及时捕获键盘消息，鼠标消息和其他外设出发的消息。比如可以记录键盘事件。下图就是此程序运行后 成功捕获到键盘和鼠标消息的截图。本程序采用I/O多路复用技术。#include#include #include #include #include #include #include #include #includeint b_cur_x = 0, b_cur_y = 0;typedef enum BlcTermKeyDevStat_Default = 1, / 所有键值的默认状态或鼠标的坐标移动状态 BlcTermKeyDevStat_Down = 2, / 所有键值的按下状态 BlcTermKeyDevStat_Up = 3, / 所有键值的弹起状态 BlcTermKeyDevStat_MouseWheel= 4, / 鼠标滚轮转动 BlcTermKeyDevStat_ConsoleLeftAXIS = 5, / 游戏手柄左摇杆坐标操作 BlcTermKeyDevStat_ConsoleRightAXIS = 6, / 游戏手柄右摇杆坐标操作 BlcTermKeyDevStat_MouseDoubleClick = 7, / 鼠标左键双击BlcTermKeyDevStat;typedef enum BlcPlayCtl_EventID_Login= 3001,BlcPlayCtl_EventID_Logout= 3002,BlcDmxFilter_EventID_TSData= 3003,BlcKey_EventID_KeyValue= 3004,BlcPlayCtl_EventID_MwReturn= 3005,BlcRes_EventID_ResoureRequest= 3006,BlcRes_EventID_ServiceNotice= 3007,BlcPlayCtl_EventID_ConnectServer= 3008,BlcKey_EventID_KeyDevPlug= 3101, Blc_EventID;typedef enum BlcKeyDevPlugType_KeyboardPlugin= 1,BlcKeyDevPlugType_KeyboardPlugout= 2,BlcKeyDevPlugType_MousePlugin= 3,BlcKeyDevPlugType_MousePlugout= 4,BlcKeyDevPlugType_ConsolePlugin= 5,BlcKeyDevPlugType_ConsolePlugout= 6, BlcKeyDevPlugType;typedef enum BlcTermKeyDevType_Irr= 1,BlcTermKeyDevType_Keyboard= 2,BlcTermKeyDevType_Mouse= 3,BlcTermKeyDevType_Console= 4, BlcTermKeyDevType;typedef enum BlcMousePropertyValue_DEFAULT = 0, BlcMousePropertyValue_BUTTONLEFT = 1, BlcMousePropertyValue_BUTTONMIDDLE = 2, BlcMousePropertyValue_BUTTONRIGHT = 3, BlcMouseKeyValue;typedef struct int keydev; /键值设备类型int keystate; / 键值状态;int keyvalue; / 键值shortx;/鼠标的x坐标shorty;/鼠标的y坐标 BlcKeyValueData;struct input_event ev_temp;int func(int fd)BlcKeyValueData key_info;int count;int plug_flag = BlcKeyDevPlugType_MousePlugout;/struct input_event ev_temp; if(fd != -1) plug_flag = BlcKeyDevPlugType_MousePlugin; char up = 抬起;char down = 按下; /while(1) count = read(fd, &ev_temp, sizeof(struct input_event);if(count 0)if(ev_temp.type = EV_SYN) return 1;printf($: %d, %d, %dn, ev_temp.type, ev_temp.code, ev_temp.value);printf(key:%d , ev_temp.code);printf(%sn, ev_temp.value?down:up);memset(&key_info, 0 , sizeof(BlcKeyValueData);if (ev_temp.type = EV_KEY)if (ev_temp.code = 0 & ev_temp.code = 0x110 & ev_temp.code = 0x116)key_info.keydev = BlcTermKeyDevType_Mouse;if (ev_temp.code = 0x110)key_info.keyvalue = BlcMousePropertyValue_BUTTONLEFT; else if (ev_temp.code = 0x111)key_info.keyvalue = BlcMousePropertyValue_BUTTONRIGHT; else if (ev_temp.code = 0x112)key_info.keyvalue = BlcMousePropertyValue_BUTTONMIDDLE; if (ev_temp.value = 1)key_info.keystate = BlcTermKeyDevStat_Down;else if (ev_temp.value = 0)key_info.keystate = BlcTermKeyDevStat_Up;key_info.x = -1;key_info.y = -1;else if (ev_temp.type = EV_REL)key_info.keydev = BlcTermKeyDevType_Mouse;key_info.keystate = BlcTermKeyDevStat_Default;key_info.keyvalue = 0;if (ev_temp.code = REL_X)b_cur_x += ev_temp.value;else if (ev_temp.code = REL_Y)b_cur_y += ev_temp.value;else if (ev_temp.code = REL_WHEEL);/?/key_info.keyvalue = ev_temp.code;if (b_cur_x 1280) b_cur_x = 1280;if (b_cur_y 720) b_cur_y = 720;key_info.x = b_cur_x;key_info.y = 0 - b_cur_y;printf(: %d, %d, %dn, key_info.keydev, key_info.keyvalue, key_info.keyvalue);else if (count = -1)if (plug_flag = BlcKeyDevPlugType_MousePlugin)close(fd);plug_flag = BlcKeyDevPlugType_MousePlugout;printf(plug out !n);if (fd != -1)plug_flag = BlcKeyDevPlugType_MousePlugin;printf(plug int ok !n);elseprintf(plug int fail !n);usleep(500);/ int main(void) int fd_key,fd_ts, fd_led, fd_max, fd_0, fd_2, fd_3; struct input_event event_key,event_ts; int dac_value; struct timeval select_timeout; fd_set readfds; select_timeout.tv_sec = 20; select_timeout.tv_usec = 0; fd_0 = open(/dev/input/event0, O_RDWR); fd_key = open(/dev/input/event1, O_RDWR); fd_2 = open(/dev/input/event2, O_RDWR); fd_3 = open(/dev/input/event3, O_RDWR); fd_ts = open(/dev/input/event4, O_RDWR); if (fd_keyfd_ts) fd_max = fd_key; else fd_max = fd_ts; while(1) F