[libusb] Can't write to a control endpoint in libusb-1.0.16_RC10, when bulk transfer (printing) is going on in interface 0

[Kumar, S. <san...@hp...>]

#include <unistd.h>
#include <errno.h>
#include <stdio.h>
#include<stdlib.h>
#include <string.h>
#include <libusb-1.0/libusb.h>
#include <error.h>
#include <syslog.h>


#define LIBUSB_TIMEOUT 30000              /* milliseconds */
#define LIBUSB_CONTROL_REQ_TIMEOUT 5000

#define DBG(args...) printf(args)
#define INFO(args...) printf(args)
#define BUG(args...) printf(args)

static int get_ep(libusb_device *dev, int config, int interface, int altset, enum libusb_transfer_type type, enum libusb_endpoint_direction epdir)
{
        struct libusb_config_descriptor *confptr = NULL;
        const struct libusb_interface_descriptor *pi;
        int i, endpoint = -1;

        if (libusb_get_config_descriptor(dev, config, &confptr) != 0)
                goto bugout;

        if (confptr == NULL || confptr->interface == NULL || confptr->interface[interface].altsetting == NULL)
                goto bugout;

        pi = &(confptr->interface[interface].altsetting[altset]);
        for (i=0; i<pi->bNumEndpoints; i++) {
                if (pi->endpoint == NULL)
                        goto bugout;
                if (pi->endpoint[i].bmAttributes == type) {
                        if (epdir == LIBUSB_ENDPOINT_IN) {
                                if (pi->endpoint[i].bEndpointAddress & LIBUSB_ENDPOINT_IN) {
                                        endpoint = pi->endpoint[i].bEndpointAddress;
                                        break;
                                }
                        } else if (epdir == LIBUSB_ENDPOINT_OUT) {
                                if (!(pi->endpoint[i].bEndpointAddress & LIBUSB_ENDPOINT_IN)) {
                                        endpoint = pi->endpoint[i].bEndpointAddress;
                                        break;
                                }
                        }
                }
        }

bugout:
        libusb_free_config_descriptor(confptr);
        if (endpoint == -1)
                DBG("get_ep: ERROR! returning -1\n");
        return endpoint; /* no endpoint found */
}

static int get_out_ep(libusb_device *dev, int config, int interface, int altset, enum libusb_transfer_type type)
{
        return get_ep(dev, config, interface, altset, type, LIBUSB_ENDPOINT_OUT);
}

/* Detach any kernel module that may have claimed specified inteface. */
static int detach(libusb_device_handle *hd, int interface)
{
        int ret ;
        /* If any kernel module has claimed this interface, detach it. */
        ret = libusb_kernel_driver_active (hd, interface);
        DBG("Active kernel driver on interface=%d ret=%d (%m)\n", interface, ret);
        if (ret == 1) {
                ret = libusb_detach_kernel_driver(hd, interface);
                DBG("Detaching kernel driver on interface=%d ret=%d (%m)\n", interface, ret);
                if (ret < 0)
                        BUG("could not remove kernel driver interface=%d, retvalue = %d: %m\n",  interface,ret);
        }
      
        ret = libusb_kernel_driver_active (hd, interface);         
        DBG("Varify Active kernel driver on interface=%d ret=%d (%m)...............\n", interface, ret);

        return 0;
}


int main(int argc, char **argv)
{
        libusb_context *ctx = NULL;
        libusb_device **list; /*List of connected USB devices */
        libusb_device *dev = NULL; /* Current device */
        struct libusb_device_descriptor devdesc; /* Current device descriptor */
        struct libusb_config_descriptor *confptr = NULL; /* Pointer to current configuration */
        libusb_device_handle *hd = NULL;
        int i, j = 0,r, conf, numdevs = 0,status;       /* number of connected devices */
        char imanufact[128] = {0,} , iproduct[128] = {0,}, iserial[128] = {0,};
        int num = 0;
        char string[128] = {0,};
        
        char buffer[1024]={0};
        int maxSize = 1024,size = 1024, rlen=-4, interfacenum=0;


        libusb_init(&ctx);
        libusb_set_debug(ctx,2);

        numdevs = libusb_get_device_list(ctx, &list);
        if (numdevs <= 0)
                goto bugout;

        for (i = 0; i < numdevs; i++) {
                dev = list[i];

                libusb_get_device_descriptor (dev, &devdesc);

                if (!devdesc.bNumConfigurations || !devdesc.idVendor || !devdesc.idProduct)
                        continue;

                if(devdesc.idVendor != 0x3f0) /*Not a HP device */
                        continue;

                for (conf = 0; conf < devdesc.bNumConfigurations; conf++) {
                        if (libusb_get_config_descriptor (dev, conf, &confptr) < 0)
                                continue;

                        if (confptr->interface[0].altsetting[0].bInterfaceClass != LIBUSB_CLASS_MASS_STORAGE) {

                                libusb_open(dev, &hd);
                                if (hd == NULL) {
                                        BUG("Invalid usb_open: %m\n");
                                        continue;
                                }

				detach(hd, 0);
				DBG("\n");

				rlen = libusb_claim_interface(hd, 0);
				if (rlen)
					DBG("invalid claim_interface %d: (%m)\n",0);
				else
					DBG("claimed interface : %d  (%m)\n",interfacenum);

				rlen = libusb_control_transfer(hd,
						LIBUSB_ENDPOINT_IN | LIBUSB_REQUEST_TYPE_CLASS | LIBUSB_RECIPIENT_INTERFACE , /* bmRequestType */
						LIBUSB_REQUEST_GET_STATUS,        /* bRequest */
						0,        /* wValue */
						0, /* wIndex interface */    /* note firmware does not follow the USB Printer Class specification for wIndex */
						buffer, maxSize, LIBUSB_CONTROL_REQ_TIMEOUT);

				if (rlen < 0)
					BUG("invalid deviceid ret=%d: (%m)\n\n", rlen);
				else
					BUG("Valid deviceid ret=%d: (%m)\n\n", rlen);


				rlen = ntohs(*(short *)buffer);
				if (rlen > (size-1))
					rlen = size-1;   /* leave byte for zero termination */
				if (rlen > 2)
					rlen -= 2;
				memcpy(buffer, buffer+2, rlen);    /* remove length */
				buffer[rlen]=0;
				DBG("read actual device_id successfully fd=%d len=%d (%m)\n\n", 1, rlen);

				BUG("device ID:%s: \n\n", buffer);


				libusb_free_config_descriptor(confptr);
				confptr = NULL;
                        }
                }
        }


bugout:
        if (hd)
                libusb_close(hd);
        if (confptr)
                libusb_free_config_descriptor(confptr);
        libusb_free_device_list(list, 1);
        libusb_exit(ctx);
        return 0;
}