遍历USB设备，获取扫描仪序列号

理论:
    对于USB接口的设备，现在越来越多了。本篇我们就通过获取一个USB扫描仪设备中的序列号，来介绍如何获取usb设备的一些硬件信息。对于usb设备都是采用HCD0,HCD1,HCD2,HCD3等符号描述的。如下图：

因此，有了这个名字，我们就可以使用CreateFile来打开usb设备。然后使用DeviceIoControl函数与usb设备通讯了。HCD是host controller driver的简写。需要了解详情的，还要仔细的阅读usb协议。
usb的通讯基本步骤如下图所示：

基本步骤：
    1）打开HCD%X
    2) 得到上面的USB root hub
    3) 遍历usb root hub上连接的usb 设备。获取信息
    4）如果有多个usb口，循环前3步。

下面介绍通讯用的几个IOCTL:
1) USB_HCD_DRIVERKEY_NAME ,用于获取USB设备驱动在注册表中的键名。相应的一个结构体是：
typedef struct _USB_HCD_DRIVERKEY_NAME
{
   ULONG   ActualLength;
   WCHAR   DriverKeyName[1];
} USB_HCD_DRIVERKEY_NAME, *PUSB_HCD_DRIVERKEY_NAME;

2） IOCTL_USB_GET_ROOT_HUB_NAME， 用于获取root hub 键名。使用的结构体，跟上面一样。
typedef struct _USB_ROOT_HUB_NAME
{
    ULONG ActualLength;
    WCHAR RootHubName[1];
} USB_ROOT_HUB_NAME, *PUSB_ROOT_HUB_NAME;

3）IOCTL_USB_GET_NODE_INFORMATION， 用于获取连接在root hub上的节点设备信息。也就是我们接在usb口上的所有usb设备的信息，对应的结构体：
typedef struct _USB_NODE_INFORMATION
{
    USB_HUB_NODE NodeType;   
    union {
        USB_HUB_INFORMATION HubInformation;
        USB_MI_PARENT_INFORMATION MiParentInformation;
    } u;
} USB_NODE_INFORMATION, *PUSB_NODE_INFORMATION;

typedef struct _USB_MI_PARENT_INFORMATION
{
    ULONG NumberOfInterfaces;
} USB_MI_PARENT_INFORMATION, *PUSB_MI_PARENT_INFORMATION;

typedef struct _USB_HUB_INFORMATION
{
    USB_HUB_DESCRIPTOR HubDescriptor;

    BOOLEAN HubIsBusPowered;

} USB_HUB_INFORMATION, *PUSB_HUB_INFORMATION;


typedef struct _USB_HUB_DESCRIPTOR
{
    UCHAR        bDescriptorLength;      // Length of this descriptor
    UCHAR        bDescriptorType;        // Hub configuration type
    UCHAR        bNumberOfPorts;         // number of ports on this hub
    USHORT       wHubCharacteristics;    // Hub Charateristics
    UCHAR        bPowerOnToPowerGood;    // port power on till power good in 2ms
    UCHAR        bHubControlCurrent;     // max current in mA
    //
    // room for 255 ports power control and removable bitmask
    UCHAR        bRemoveAndPowerMask[64];      
} USB_HUB_DESCRIPTOR, *PUSB_HUB_DESCRIPTOR;

4) IOCTL_USB_GET_NODE_CONNECTION_INFORMATION, 用于获取接在usb口上的单个usb设备的信息，对应的结构体：

typedef struct _USB_NODE_CONNECTION_INFORMATION
{
    ULONG ConnectionIndex;
    USB_DEVICE_DESCRIPTOR DeviceDescriptor;
    UCHAR CurrentConfigurationValue;
    BOOLEAN LowSpeed;

    BOOLEAN DeviceIsHub;

    USHORT DeviceAddress;

    ULONG NumberOfOpenPipes;

    USB_CONNECTION_STATUS ConnectionStatus;
    USB_PIPE_INFO PipeList[0];
} USB_NODE_CONNECTION_INFORMATION, *PUSB_NODE_CONNECTION_INFORMATION;

4）IOCTL_USB_GET_DESCRIPTOR_FROM_NODE_CONNECTION， 用于获取usb设备的描述信息。
typedef struct _USB_DEVICE_DESCRIPTOR
{
    UCHAR bLength;
    UCHAR bDescriptorType;
    USHORT bcdUSB;
    UCHAR bDeviceClass;
    UCHAR bDeviceSubClass;
    UCHAR bDeviceProtocol;
    UCHAR bMaxPacketSize0;
    USHORT idVendor;
    USHORT idProduct;
    USHORT bcdDevice;
    UCHAR iManufacturer;
    UCHAR iProduct;
    UCHAR iSerialNumber;
    UCHAR bNumConfigurations;
} USB_DEVICE_DESCRIPTOR, *PUSB_DEVICE_DESCRIPTOR;

typedef struct _USB_DEVICE_DESCRIPTOR
{
    UCHAR bLength;
    UCHAR bDescriptorType;
    USHORT bcdUSB;
    UCHAR bDeviceClass;
    UCHAR bDeviceSubClass;
    UCHAR bDeviceProtocol;
    UCHAR bMaxPacketSize0;
    USHORT idVendor;
    USHORT idProduct;
    USHORT bcdDevice;
    UCHAR iManufacturer;
    UCHAR iProduct;
    UCHAR iSerialNumber;
    UCHAR bNumConfigurations;
} USB_DEVICE_DESCRIPTOR, *PUSB_DEVICE_DESCRIPTOR;

typedef enum _USB_CONNECTION_STATUS
{
    NoDeviceConnected,
    DeviceConnected,

    /* failure codes, these map to fail reasons */
    DeviceFailedEnumeration,
    DeviceGeneralFailure,
    DeviceCausedOvercurrent,
    DeviceNotEnoughPower,
    DeviceNotEnoughBandwidth,
    DeviceHubNestedTooDeeply,
    DeviceInLegacyHub
} USB_CONNECTION_STATUS, *PUSB_CONNECTION_STATUS;

typedef struct _USB_PIPE_INFO
{
    USB_ENDPOINT_DESCRIPTOR EndpointDescriptor;
    ULONG ScheduleOffset;
} USB_PIPE_INFO, *PUSB_PIPE_INFO;

typedef struct _USB_ENDPOINT_DESCRIPTOR
{
    UCHAR bLength;
    UCHAR bDescriptorType;
    UCHAR bEndpointAddress;
    UCHAR bmAttributes;
    USHORT wMaxPacketSize;
    UCHAR bInterval;
} USB_ENDPOINT_DESCRIPTOR, *PUSB_ENDPOINT_DESCRIPTOR;

需要注意一点，如果要得到pid,vid,则直接从 USB_DEVICE_DESCRIPTOR结构中取出 idVendor， idProduct这两项的值就行了。如果要得到序列号，则不是取出 iSerialNumber就可以的。这里的 iSerialNumber仅仅是一个索引值。如果想得到序列号，就需要定义一个结构，然后给设备发送个请求。请求的结构如下图：

代码参照GetStringDescriptor函数。可以根据 iSerialNumber偏移，取出其对应的字符串，存放在上图USB_STRING_DESCRIPTOR结构中。

代码：见光盘GetSerialNo

#include "windows.h"
#include "PlkUsbIo.h"
#include <malloc.h>

#define NUM_HCS_TO_CHECK 10

/******************************************************************/
bool EnumUsbDevice();
PCHAR GetDriverKeyName(HANDLE Hub, ULONG ConnectionIndex);
PCHAR GetHCDDriverKeyName(HANDLE HCD);
PCHAR GetRootHubName(HANDLE HostController);
PCHAR WideStrToMultiStr(PWCHAR WideStr);
bool GetStringDescriptor (
        HANDLE hHubDevice,
        ULONG   ConnectionIndex,
        UCHAR   DescriptorIndex    ,
        CHAR * outBuff);
   
/******************************************************************/

int main(int argc, char* argv[])
{
    EnumUsbDevice()；
    return 0;
}

bool EnumUsbDevice()
{
    char        HCName[16];
    int         HCNum;
    HANDLE      hHCDev;
    PCHAR       rootHubName;

    ULONG       index;
    BOOL        success;

    PUSB_NODE_CONNECTION_INFORMATION    connectionInfo;
    HANDLE hHubDevice;

    for (HCNum = 0; HCNum < NUM_HCS_TO_CHECK; HCNum++)
    {
        wsprintf(HCName, "////.//HCD%d", HCNum);
        hHCDev = CreateFile(HCName,
            GENERIC_WRITE,
            FILE_SHARE_WRITE,
            NULL,
            OPEN_EXISTING,
            0,
            NULL);
        if (hHCDev == INVALID_HANDLE_VALUE)   
            break;
       
        PCHAR driverKeyName, deviceDesc;
        driverKeyName = GetHCDDriverKeyName(hHCDev);
        if(driverKeyName == NULL)
            goto end;   
       
   
        ULONG nBytes;
        rootHubName =(char*) GetRootHubName(hHCDev);
        if(rootHubName==NULL)
            goto end;
   
        PUSB_NODE_INFORMATION HubInfo;
        HubInfo = (PUSB_NODE_INFORMATION)malloc(sizeof(USB_NODE_INFORMATION));
        PCHAR deviceName;
        deviceName = (PCHAR)malloc(strlen(rootHubName) + sizeof("////.//"));
        if (rootHubName != NULL)
        {
            strcpy(deviceName, "////.//");
            strcpy(deviceName + sizeof("////.//") - 1, rootHubName);
            hHubDevice = CreateFile(deviceName,
                GENERIC_WRITE,
                FILE_SHARE_WRITE,
                NULL,
                OPEN_EXISTING,
                0,
                NULL);
            free(deviceName);
            if (hHubDevice == INVALID_HANDLE_VALUE)
                goto end;
           
            success = DeviceIoControl(hHubDevice,
                IOCTL_USB_GET_NODE_INFORMATION,
                HubInfo,
                sizeof(USB_NODE_INFORMATION),
                HubInfo,
                sizeof(USB_NODE_INFORMATION),
                &nBytes,
                NULL);
            if (!success)
                goto end;
           

        }

        int port;
        port=HubInfo->u.HubInformation.HubDescriptor.bNumberOfPorts;
        for (index=1; index <= port; index++)
        {
            ULONG nBytes;
            nBytes = sizeof(USB_NODE_CONNECTION_INFORMATION) +
                sizeof(USB_PIPE_INFO) * 30;
            connectionInfo = (PUSB_NODE_CONNECTION_INFORMATION)malloc(nBytes);
            if (connectionInfo == NULL)
                goto end;
           
            connectionInfo->ConnectionIndex = index;
            success = DeviceIoControl(hHubDevice,
                IOCTL_USB_GET_NODE_CONNECTION_INFORMATION,
                connectionInfo,
                nBytes,
                connectionInfo,
                nBytes,
                &nBytes,
                NULL);
            if (!success)
            {
                free(connectionInfo);
                goto end;
            }
       

            deviceDesc = NULL;
            if (connectionInfo->ConnectionStatus != NoDeviceConnected)
            {
                driverKeyName = GetDriverKeyName(hHubDevice,
                    index);
                if (driverKeyName)
                {
                    free(driverKeyName);
                }
            }

            if (connectionInfo->ConnectionStatus == DeviceConnected)
            {
                //取出序列号索引
                UCHAR nSerialno = connectionInfo->DeviceDescriptor.iSerialNumber;
                CHAR OutBuff[20] = {0};
                GetStringDescriptor(hHubDevice,connectionInfo->ConnectionIndex,nSerialno,OutBuff);

                //判断序列号是否有效
                if( 序列号是否有效 )
                {
                      CloseHandle(hHubDevice);
                      CloseHandle(hHCDev);
                     return true;
                }
            }

        }
end:;
    }

    CloseHandle(hHubDevice);
    CloseHandle(hHCDev);
    return false;
}

PCHAR GetDriverKeyName(HANDLE Hub, ULONG ConnectionIndex)
{
    BOOL                                success;
    ULONG                               nBytes;
    USB_NODE_CONNECTION_DRIVERKEY_NAME driverKeyName;
    PUSB_NODE_CONNECTION_DRIVERKEY_NAME driverKeyNameW;
    PCHAR                               driverKeyNameA;

    driverKeyNameW = NULL;
    driverKeyNameA = NULL;

    driverKeyName.ConnectionIndex = ConnectionIndex;

    success = DeviceIoControl(Hub,
        IOCTL_USB_GET_NODE_CONNECTION_DRIVERKEY_NAME,
        &driverKeyName,
        sizeof(driverKeyName),
        &driverKeyName,
        sizeof(driverKeyName),
        &nBytes,
        NULL);

    if (!success)
    {
        goto GetDriverKeyNameError;
    }

    nBytes = driverKeyName.ActualLength;

    if (nBytes <= sizeof(driverKeyName))
    {
        goto GetDriverKeyNameError;
    }

    driverKeyNameW = (PUSB_NODE_CONNECTION_DRIVERKEY_NAME)malloc(nBytes);

    if (driverKeyNameW == NULL)
    {
        goto GetDriverKeyNameError;
    }

    driverKeyNameW->ConnectionIndex = ConnectionIndex;

    success = DeviceIoControl(Hub,
        IOCTL_USB_GET_NODE_CONNECTION_DRIVERKEY_NAME,
        driverKeyNameW,
        nBytes,
        driverKeyNameW,
        nBytes,
        &nBytes,
        NULL);

    if (!success)
    {
        goto GetDriverKeyNameError;
    }
    driverKeyNameA = WideStrToMultiStr(driverKeyNameW->DriverKeyName);
    free(driverKeyNameW);

    return driverKeyNameA;


GetDriverKeyNameError:
    if (driverKeyNameW != NULL)
    {
        free(driverKeyNameW);
        driverKeyNameW = NULL;
    }

    return NULL;
}
PCHAR GetRootHubName(HANDLE HostController)
{
    BOOL                success;
    ULONG               nBytes;
    USB_ROOT_HUB_NAME   rootHubName;
    PUSB_ROOT_HUB_NAME rootHubNameW;
    PCHAR               rootHubNameA;

    rootHubNameW = NULL;
    rootHubNameA = NULL;

    success = DeviceIoControl(HostController,
        IOCTL_USB_GET_ROOT_HUB_NAME,
        0,
        0,
        &rootHubName,
        sizeof(rootHubName),
        &nBytes,
        NULL);

    if (!success)
    {
        goto GetRootHubNameError;
    }

    nBytes = rootHubName.ActualLength;

    rootHubNameW =(PUSB_ROOT_HUB_NAME) malloc(nBytes);

    if (rootHubNameW == NULL)
    {

        goto GetRootHubNameError;
    }

    success = DeviceIoControl(HostController,
        IOCTL_USB_GET_ROOT_HUB_NAME,
        NULL,
        0,
        rootHubNameW,
        nBytes,
        &nBytes,
        NULL);

    if (!success)
    {
        goto GetRootHubNameError;
    }

    rootHubNameA = WideStrToMultiStr(rootHubNameW->RootHubName);
    free(rootHubNameW);

    return rootHubNameA;


GetRootHubNameError:
    if (rootHubNameW != NULL)
    {
        free(rootHubNameW);
        rootHubNameW = NULL;
    }

    return NULL;
}
PCHAR GetHCDDriverKeyName(HANDLE HCD)
{
    BOOL                    success;
    ULONG                   nBytes;
    USB_HCD_DRIVERKEY_NAME driverKeyName;
    PUSB_HCD_DRIVERKEY_NAME driverKeyNameW;
    PCHAR                   driverKeyNameA;

    driverKeyNameW = NULL;
    driverKeyNameA = NULL;

    success = DeviceIoControl(HCD,
        IOCTL_GET_HCD_DRIVERKEY_NAME,
        &driverKeyName,
        sizeof(driverKeyName),
        &driverKeyName,
        sizeof(driverKeyName),
        &nBytes,
        NULL);

    if (!success)
    {
        goto GetHCDDriverKeyNameError;
    }

    nBytes = driverKeyName.ActualLength;

    if (nBytes <= sizeof(driverKeyName))
    {
        goto GetHCDDriverKeyNameError;
    }

    driverKeyNameW =(PUSB_HCD_DRIVERKEY_NAME) malloc(nBytes);

    if (driverKeyNameW == NULL)
    {
        goto GetHCDDriverKeyNameError;
    }

    success = DeviceIoControl(HCD,
        IOCTL_GET_HCD_DRIVERKEY_NAME,
        driverKeyNameW,
        nBytes,
        driverKeyNameW,
        nBytes,
        &nBytes,
        NULL);

    if (!success)
    {
        goto GetHCDDriverKeyNameError;
    }

    driverKeyNameA = WideStrToMultiStr(driverKeyNameW->DriverKeyName);
    free(driverKeyNameW);

    return driverKeyNameA;


GetHCDDriverKeyNameError:
    if (driverKeyNameW != NULL)
    {
        free(driverKeyNameW);
        driverKeyNameW = NULL;
    }

    return NULL;
}

PCHAR WideStrToMultiStr(PWCHAR WideStr)
{
    ULONG nBytes;
    PCHAR MultiStr;
    nBytes = WideCharToMultiByte(
        CP_ACP,
        0,
        WideStr,
        -1,
        NULL,
        0,
        NULL,
        NULL);

    if (nBytes == 0)
    {
        return NULL;
    }
    MultiStr =(PCHAR) malloc(nBytes);

    if (MultiStr == NULL)
    {
        return NULL;
    }
    nBytes = WideCharToMultiByte(
        CP_ACP,
        0,
        WideStr,
        -1,
        MultiStr,
        nBytes,
        NULL,
        NULL);

    if (nBytes == 0)
    {
        free(MultiStr);
        return NULL;
    }

    return MultiStr;
}


bool    GetStringDescriptor (
        HANDLE hHubDevice,
        ULONG   ConnectionIndex,
        UCHAR   DescriptorIndex    ,
        CHAR * outBuff
        )
    {
        BOOL    success;
        ULONG   nBytes;
        ULONG   nBytesReturned;

        UCHAR   stringDescReqBuf[sizeof(USB_DESCRIPTOR_REQUEST) + MAXIMUM_USB_STRING_LENGTH];

        PUSB_DESCRIPTOR_REQUEST stringDescReq;
        PUSB_STRING_DESCRIPTOR stringDesc;

        nBytes = sizeof(stringDescReqBuf);

        stringDescReq = (PUSB_DESCRIPTOR_REQUEST)stringDescReqBuf;
        stringDesc = (PUSB_STRING_DESCRIPTOR)(stringDescReq+1);

   
        ::ZeroMemory(stringDescReq,nBytes);
        stringDescReq->ConnectionIndex = ConnectionIndex;
        stringDescReq->SetupPacket.wValue = (USB_STRING_DESCRIPTOR_TYPE << 8) | DescriptorIndex;
        stringDescReq->SetupPacket.wIndex = GetSystemDefaultLangID();
        stringDescReq->SetupPacket.wLength = (USHORT)(nBytes - sizeof(USB_DESCRIPTOR_REQUEST));

        success = DeviceIoControl(hHubDevice,IOCTL_USB_GET_DESCRIPTOR_FROM_NODE_CONNECTION,
                                stringDescReq,nBytes,
                                stringDescReq,nBytes,
                                &nBytesReturned,NULL);

        if (!success || nBytesReturned < 2)
            return false;

        if (stringDesc->bDescriptorType != USB_STRING_DESCRIPTOR_TYPE)
            return false;

        if (stringDesc->bLength != nBytesReturned - sizeof(USB_DESCRIPTOR_REQUEST))
            return false;

        if (stringDesc->bLength % 2 != 0)
            return false;

        WCHAR * wChar = new WCHAR[stringDesc->bLength + 1];
        memcpy(wChar,stringDesc->bString,stringDesc->bLength);
        char *szTemp = WideStrToMultiStr(wChar);
        lstrcpy(outBuff, szTemp);
       
        if(szTemp)
        delete []szTemp;
       
        if(wChar)
        delete []wChar;
        return true;
    }

分析：

1）首先假定有10个usb接口
    #define NUM_HCS_TO_CHECK 10

2）循环打开这10个usb端口，如果端口没有这么多，调用 CreateFile， 就会返回 INVALID_HANDLE_VALUE。
    for (HCNum = 0; HCNum < NUM_HCS_TO_CHECK; HCNum++)
    {
        wsprintf(HCName, "////.//HCD%d", HCNum);
        hHCDev = CreateFile(HCName,
            GENERIC_WRITE,
            FILE_SHARE_WRITE,
            NULL,
            OPEN_EXISTING,
            0,
            NULL);
        if (hHCDev == INVALID_HANDLE_VALUE)   
            break;

3）获取root hub
       ULONG nBytes;
        rootHubName =(char*) GetRootHubName(hHCDev);
        if(rootHubName==NULL)
            goto end;

4) 遍历连接在root hub上的节点
        int port;
        port=HubInfo->u.HubInformation.HubDescriptor.bNumberOfPorts;
        for (index=1; index <= port; index++)
        {
            ULONG nBytes;
            nBytes = sizeof(USB_NODE_CONNECTION_INFORMATION) +
                sizeof(USB_PIPE_INFO) * 30;
            connectionInfo = (PUSB_NODE_CONNECTION_INFORMATION)malloc(nBytes);
            if (connectionInfo == NULL)
                goto end;
           
            connectionInfo->ConnectionIndex = index;
            success = DeviceIoControl(hHubDevice,
                IOCTL_USB_GET_NODE_CONNECTION_INFORMATION,
                connectionInfo,
                nBytes,
                connectionInfo,
                nBytes,
                &nBytes,
                NULL);
            if (!success)
            {
                free(connectionInfo);
                goto end;
            }

5）根据节点的连接状态，获取节点信息，得到序列号。
    if (connectionInfo->ConnectionStatus == DeviceConnected)
            {
                //取出序列号索引
                UCHAR nSerialno = connectionInfo->DeviceDescriptor.iSerialNumber;
                CHAR OutBuff[20] = {0};
                GetStringDescriptor(hHubDevice,connectionInfo->ConnectionIndex,nSerialno,OutBuff);

6）得到序列号的方法在理论部分已经详细说明了，对应的函数是 GetStringDescriptor，这里不再重复。