gistfile1.c

/*
 * Copyright (C) 2011 Hans Petter Selasky. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *  * Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *  * Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>

#include <sys/ioctl.h>
#include <sys/types.h>
#include <dirent.h>
#include <fcntl.h>
#include <errno.h>
#include <pthread.h>
#include <ctype.h>

#include <libusb.h>

#include "usb.h"

struct usb_handle {
        libusb_device_handle *handle;
        libusb_device *dev;
        unsigned char ep_in;
        unsigned char ep_out;
        unsigned char iface;
};

static int 
probe(struct usb_handle *h, ifc_match_func callback)
{
        struct usb_ifc_info info;
        libusb_device_descriptor ddesc;
        libusb_config_descriptor *pcfg;
        int i, j;

        if (libusb_open(h->dev, &h->handle) < 0)
                return (-1);

        if (libusb_get_device_descriptor(h->dev, &ddesc) < 0) {
                libusb_close(h->handle);
                return (-1);
        }
        memset(&info, 0, sizeof(info));

        info.dev_vendor = ddesc.idVendor;
        info.dev_product = ddesc.idProduct;
        info.dev_class = ddesc.bDeviceClass;
        info.dev_subclass = ddesc.bDeviceSubClass;
        info.dev_protocol = ddesc.bDeviceProtocol;

        if (ddesc.iSerialNumber != 0) {
                libusb_get_string_descriptor_ascii(h->handle, ddesc.iSerialNumber,
                    (unsigned char *)info.serial_number, sizeof(info.serial_number));
        }
        if (libusb_get_active_config_descriptor(h->dev, &pcfg)) {
                libusb_close(h->handle);
                return (-1);
        }

        for (i = 0; i < pcfg->bNumInterfaces; i++) {

                h->ep_in = 0;
                h->ep_out = 0;
                h->iface = i;

                for (j = 0; j < pcfg->interface[i].altsetting[0].bNumEndpoints; j++) {

                        unsigned char temp = pcfg->interface[i].altsetting[0].
                        endpoint[j].bEndpointAddress;
                        unsigned char type = pcfg->interface[i].altsetting[0].
                        endpoint[j].bmAttributes & 0x03;

                        /* check for BULK endpoint */
                        if ((type & 0x03) == 0x02) {
                                /* check for IN endpoint */
                                if (temp & 0x80)
                                        h->ep_in = temp;
                                else
                                        h->ep_out = temp;
                        }
                }

                info.ifc_class = pcfg->interface[i].altsetting[0].bInterfaceClass;
                info.ifc_subclass = pcfg->interface[i].altsetting[0].bInterfaceSubClass;
                info.ifc_protocol = pcfg->interface[i].altsetting[0].bInterfaceProtocol;
                info.has_bulk_in = (h->ep_in != 0);
                info.has_bulk_out = (h->ep_out != 0);

                if (libusb_claim_interface(h->handle, h->iface) < 0)
                        continue;

                if (callback(&info) == 0) {
                        libusb_free_config_descriptor(pcfg);
                        return (0);
                }
                libusb_release_interface(h->handle, h->iface);
        }

        libusb_free_config_descriptor(pcfg);
        libusb_close(h->handle);
        return (-1);
}

static usb_handle *
enumerate(ifc_match_func callback)
{
        static libusb_context *ctx = NULL;
        usb_handle *h;
        libusb_device **ppdev;
        ssize_t ndev;
        ssize_t x;

        h = malloc(sizeof(*h));
        if (h == NULL)
                return (h);

        if (ctx == NULL)
                libusb_init(&ctx);

        ndev = libusb_get_device_list(ctx, &ppdev);
        for (x = 0; x < ndev; x++) {

                memset(h, 0, sizeof(*h));

                h->dev = ppdev[x];

                if (probe(h, callback) == 0) {
                        libusb_ref_device(h->dev);
                        libusb_free_device_list(ppdev, 1);
                        return (h);
                }
        }
        free(h);
        libusb_free_device_list(ppdev, 1);
        return (NULL);
}

int 
usb_write(usb_handle * h, const void *_data, int len)
{
        int actlen;

        if (libusb_bulk_transfer(h->handle, h->ep_out, (void *)(long)_data, len, &actlen, 0) < 0)
                return (-1);
        return (actlen);
}

int 
usb_read(usb_handle * h, void *_data, int len)
{
        int actlen;

        if (libusb_bulk_transfer(h->handle, h->ep_in, _data, len, &actlen, 0) < 0)
                return (-1);
        return (actlen);
}

int 
usb_close(usb_handle * h)
{
        libusb_close(h->handle);
        h->handle = NULL;
        libusb_unref_device(h->dev);
        free(h);
        return (0);
}

usb_handle *
usb_open(ifc_match_func callback)
{
        return (enumerate(callback));
}