使用 libusb 在笔式驱动器上读/写:libusb_bulk_transfer() [英] Read/write on a pen drive using libusb: libusb_bulk_transfer()

问题描述

我正在尝试在 笔式驱动器上执行读写操作.

I am trying to perform read and write operations on a pen drive.

详细信息:供应商 ID:8564 和产品 ID:1000.这是 Transcend JetFlash 质量存储设备.

Details: Vendor ID: 8564 and Product ID: 1000. It is a Transcend JetFlash mass storage device.

我很想知道是否可以在笔式驱动器上实现读/写.如果是，那么它是否会按照我在下面提供的代码中尝试的方式发生.

I am keen to know that whether it is possible to achieve a read/write on a pen drive. If it is, then is it going to happen the way I have tried in the code provided below.

我已经学习了获取设备 ID、产品 ID 和端点地址的方法.这是我实施的.

I have learnt the methods to get the device id, product id and endpoint addresses. This is what I have implemented.

这里设备被确认并打开.而且，连界面都声称它是成功的.

Here the device is getting acknowledged and opened. And, even the interface claims it is successful.

但是批量传输函数返回-1.

But bulk transfer functions return -1.

解释是什么?

#include <stdio.h>
#include <sys/types.h>
#include <string.h>
#include </usr/include/libusb-1.0/libusb.h>

#define BULK_EP_OUT     0x82
#define BULK_EP_IN      0x02

int main(void)
{
    int r = 0, e = 0;
    struct libusb_device_handle *handle = NULL;
    struct libusb_device **devs;
    struct libusb_device *dev;
    struct libusb_device_descriptor desc;
    char str1[256], str2[256];

    /* Init libusb */
    r = libusb_init(NULL);
    if (r < 0)
    {
        printf("\nfailed to initialise libusb\n");
        return 1;
    }

    handle = libusb_open_device_with_vid_pid(NULL, 0x8564, 0x1000);
    if(handle == NULL)
    {
        printf("\nError in device opening!");
    }
    else
        printf("\nDevice Opened");

    // Tell libusb to use the CONFIGNUM configuration of the device

    libusb_set_configuration(handle, 1);
    if(libusb_kernel_driver_active(handle, 0) == 1)
    {
        printf("\nKernel Driver Active");
        if(libusb_detach_kernel_driver(handle, 0) == 0)
            printf("\nKernel Driver Detached!");
    }

    e = libusb_claim_interface(handle, 0);
    if(e < 0)
    {
        printf("\nCannot Claim Interface");
    }
    else
        printf("\nClaimed Interface");

      /* Communicate */

    int bytes_read;
    int nbytes = 256;
    unsigned char *my_string, *my_string1;
    int transferred = 0;
    my_string = (unsigned char *) malloc (nbytes + 1);
    my_string1 = (unsigned char *) malloc (nbytes + 1);

    strcpy(my_string, "divesd");
    printf("\nTo be sent : %s", my_string);

    e = libusb_bulk_transfer(handle, BULK_EP_OUT, my_string, bytes_read, &transferred, 5000);
    printf("\nXfer returned with %d", e);
    printf("\nSent %d bytes with string: %s\n", transferred, my_string);

    libusb_bulk_transfer(handle, BULK_EP_IN, my_string1, 256, &transferred, 5000);
    printf("\nXfer returned with %d", e);     //It returns -1... This is an error, I guess.
    printf("\nReceived %d bytes with string: %s\n", transferred, my_string1);

    e = libusb_release_interface(handle, 0);
    libusb_close(handle);
    libusb_exit(NULL);
    return 0;
}

推荐答案

尝试下面给出的代码，它应该适用于 LPC2148.我已经使用 LPC2148 对此进行了测试，该 LPC2148 配置为在写入发生(来自用户空间)并且 RTC 开始运行后接收来自 USB 的中断.

Try the code given below and it should work on LPC2148. I have tested this with an LPC2148 configured to receive an interrupt from USB after a write happens (from user-space) and the RTC starts running.

回答您的问题是否涉及读/写内核驱动程序:据我研究，您必须分离内核驱动程序并使用libusb API声明接口.虽然我不确定它是否可以在不分离的情况下完成.

Answering to your question whether it involves a kernel driver in read/write or not: As far as I have studied, you have to detach the kernel driver and claim the interface using libusb APIs. Though I am not sure whether it can be done without detaching it or not.

#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <string.h>
#include </usr/local/include/libusb-1.0/libusb.h>

#define BULK_EP_OUT     0x82
#define BULK_EP_IN      0x08

int interface_ref = 0;
int alt_interface, interface_number;

int print_configuration(struct libusb_device_handle *hDevice, struct libusb_config_descriptor *config)
{
    char *data;
    int index;

    data = (char *)malloc(512);
    memset(data, 0, 512);

    index = config->iConfiguration;

    libusb_get_string_descriptor_ascii(hDevice, index, data, 512);

    printf("\nInterface Descriptors: ");
    printf("\n\tNumber of Interfaces: %d", config->bNumInterfaces);
    printf("\n\tLength: %d", config->bLength);
    printf("\n\tDesc_Type: %d", config->bDescriptorType);
    printf("\n\tConfig_index: %d", config->iConfiguration);
    printf("\n\tTotal length: %lu", config->wTotalLength);
    printf("\n\tConfiguration Value: %d", config->bConfigurationValue);
    printf("\n\tConfiguration Attributes: %d", config->bmAttributes);
    printf("\n\tMaxPower(mA): %d\n", config->MaxPower);

    free(data);
    data = NULL;
    return 0;
}

struct libusb_endpoint_descriptor* active_config(struct libusb_device *dev, struct libusb_device_handle *handle)
{
    struct libusb_device_handle *hDevice_req;
    struct libusb_config_descriptor *config;
    struct libusb_endpoint_descriptor *endpoint;
    int altsetting_index, interface_index=0, ret_active;
    int i, ret_print;

    hDevice_req = handle;

    ret_active = libusb_get_active_config_descriptor(dev, &config);
    ret_print = print_configuration(hDevice_req, config);

    for (interface_index=0;interface_index<config->bNumInterfaces;interface_index++)
    {
        const struct libusb_interface *iface = &config->interface[interface_index];
        for (altsetting_index=0; altsetting_index<iface->num_altsetting; altsetting_index++)
        {
            const struct libusb_interface_descriptor *altsetting = &iface->altsetting[altsetting_index];

            int endpoint_index;
            for(endpoint_index=0; endpoint_index<altsetting->bNumEndpoints; endpoint_index++)
            {
                const struct libusb_endpoint_desriptor *ep = &altsetting->endpoint[endpoint_index];
                endpoint = ep;
                alt_interface = altsetting->bAlternateSetting;
                interface_number = altsetting->bInterfaceNumber;
            }

            printf("\nEndPoint Descriptors: ");
            printf("\n\tSize of EndPoint Descriptor: %d", endpoint->bLength);
            printf("\n\tType of Descriptor: %d", endpoint->bDescriptorType);
            printf("\n\tEndpoint Address: 0x0%x", endpoint->bEndpointAddress);
            printf("\n\tMaximum Packet Size: %x", endpoint->wMaxPacketSize);
            printf("\n\tAttributes applied to Endpoint: %d", endpoint->bmAttributes);
            printf("\n\tInterval for Polling for data Tranfer: %d\n", endpoint->bInterval);
        }
    }
    libusb_free_config_descriptor(NULL);
    return endpoint;
}

int main(void)
{
    int r = 1;
    struct libusb_device **devs;
    struct libusb_device_handle *handle = NULL, *hDevice_expected = NULL;
    struct libusb_device *dev, *dev_expected;

    struct libusb_device_descriptor desc;
    struct libusb_endpoint_descriptor *epdesc;
    struct libusb_interface_descriptor *intdesc;

    ssize_t cnt;
    int e = 0, config2;
    int i = 0, index;
    char str1[64], str2[64];
    char found = 0;

    // Init libusb
    r = libusb_init(NULL);
    if(r < 0)
    {
        printf("\nFailed to initialise libusb\n");
        return 1;
    }
    else
        printf("\nInit successful!\n");

    // Get a list of USB devices
    cnt = libusb_get_device_list(NULL, &devs);
    if (cnt < 0)
    {
        printf("\nThere are no USB devices on the bus\n");
        return -1;
    }
    printf("\nDevice count: %d\n-------------------------------\n", cnt);

    while ((dev = devs[i++]) != NULL)
    {
        r = libusb_get_device_descriptor(dev, &desc);
        if (r < 0)
            {
            printf("Failed to get device descriptor\n");
            libusb_free_device_list(devs, 1);
            libusb_close(handle);
            break;
        }

        e = libusb_open(dev, &handle);
        if (e < 0)
        {
            printf("Error opening device\n");
            libusb_free_device_list(devs, 1);
            libusb_close(handle);
            break;
        }

        printf("\nDevice Descriptors: ");
        printf("\n\tVendor ID: %x", desc.idVendor);
        printf("\n\tProduct ID: %x", desc.idProduct);
        printf("\n\tSerial Number: %x", desc.iSerialNumber);
        printf("\n\tSize of Device Descriptor: %d", desc.bLength);
        printf("\n\tType of Descriptor: %d", desc.bDescriptorType);
        printf("\n\tUSB Specification Release Number: %d", desc.bcdUSB);
        printf("\n\tDevice Release Number: %d", desc.bcdDevice);
        printf("\n\tDevice Class: %d", desc.bDeviceClass);
        printf("\n\tDevice Sub-Class: %d", desc.bDeviceSubClass);
        printf("\n\tDevice Protocol: %d", desc.bDeviceProtocol);
        printf("\n\tMax. Packet Size: %d", desc.bMaxPacketSize0);
        printf("\n\tNumber of Configurations: %d\n", desc.bNumConfigurations);

        e = libusb_get_string_descriptor_ascii(handle, desc.iManufacturer, (unsigned char*) str1, sizeof(str1));
        if (e < 0)
        {
        libusb_free_device_list(devs, 1);
            libusb_close(handle);
            break;
        }
        printf("\nManufactured: %s", str1);

        e = libusb_get_string_descriptor_ascii(handle, desc.iProduct, (unsigned char*) str2, sizeof(str2));
        if(e < 0)
        {
        libusb_free_device_list(devs, 1);
            libusb_close(handle);
            break;
        }
        printf("\nProduct: %s", str2);
        printf("\n----------------------------------------");

        if(desc.idVendor == 0xffff && desc.idProduct == 0x4)
        {
           found = 1;
        break;
        }
    }//end of while
    if(found == 0)
    {
        printf("\nDevice NOT found\n");
        libusb_free_device_list(devs, 1);
        libusb_close(handle);
        return 1;
    }
    else
    {
        printf("\nDevice found");
        dev_expected = dev;
        hDevice_expected = handle;
    }

    e = libusb_get_configuration(handle, &config2);
    if(e!=0)
    {
        printf("\n***Error in libusb_get_configuration\n");
        libusb_free_device_list(devs, 1);
        libusb_close(handle);
        return -1;
    }
    printf("\nConfigured value: %d", config2);

    if(config2 != 1)
    {
        libusb_set_configuration(handle, 1);
        if(e!=0)
        {
            printf("Error in libusb_set_configuration\n");
            libusb_free_device_list(devs, 1);
            libusb_close(handle);
            return -1;
        }
        else
            printf("\nDevice is in configured state!");
    }

    libusb_free_device_list(devs, 1);

    if(libusb_kernel_driver_active(handle, 0) == 1)
    {
        printf("\nKernel Driver Active");
        if(libusb_detach_kernel_driver(handle, 0) == 0)
            printf("\nKernel Driver Detached!");
        else
        {
            printf("\nCouldn't detach kernel driver!\n");
            libusb_free_device_list(devs, 1);
            libusb_close(handle);
            return -1;
        }
    }

    e = libusb_claim_interface(handle, 0);
    if(e < 0)
    {
        printf("\nCannot Claim Interface");
        libusb_free_device_list(devs, 1);
        libusb_close(handle);
        return -1;
    }
    else
        printf("\nClaimed Interface\n");

    active_config(dev_expected, hDevice_expected);

    //   Communicate

    char *my_string, *my_string1;
    int transferred = 0;
    int received = 0;
    int length = 0;

    my_string = (char *)malloc(nbytes + 1);
    my_string1 = (char *)malloc(nbytes + 1);

    memset(my_string, '\0', 64);
    memset(my_string1, '\0', 64);

    strcpy(my_string, "Prasad Divesd");
    length = strlen(my_string);

    printf("\nTo be sent: %s", my_string);

    e = libusb_bulk_transfer(handle, BULK_EP_IN, my_string, length, &transferred, 0);
    if(e == 0 && transferred == length)
    {
        printf("\nWrite successful!");
        printf("\nSent %d bytes with string: %s\n", transferred, my_string);
    }
    else
        printf("\nError in write! e = %d and transferred = %d\n", e, transferred);

    sleep(3);
    i = 0;

    for(i = 0; i < length; i++)
    {
        e = libusb_bulk_transfer(handle, BULK_EP_OUT, my_string1, 64, &received, 0);  //64: Max Packet Length
        if(e == 0)
        {
            printf("\nReceived: ");
            printf("%c", my_string1[i]); //Will read a string from LPC2148
            sleep(1);
        }
        else
        {
            printf("\nError in read! e = %d and received = %d\n", e, received);
            return -1;
        }
    }

    e = libusb_release_interface(handle, 0);

    libusb_close(handle);
    libusb_exit(NULL);

    printf("\n");
    return 0;
}

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