usb.c

   1
   2 #include <stdio.h>
   3 #include <string.h>
   4 #include <stdlib.h>
   5 #include <errno.h>
   6 #include <libusb.h>
   7
   8
   9
  10
  11 static int ncusb_match_string(libusb_device_handle *dev, int index, const char* string)
  12 {
  13         unsigned char tmp[256];
  14         libusb_get_string_descriptor_ascii(dev, index, tmp, 256);
  15         if (string == NULL)
  16                 return 1; /* NULL matches anything */
  17         return (strcmp(string, (char*) tmp)==0);
  18 }
  19
  20
  21 struct libusb_device_handle *ncusb_find_and_open(struct libusb_context *ctx,
  22                                           int vendor, int product,
  23                                           const char *vendor_name,
  24                                           const char *product_name,
  25                                           const char *serial)
  26 {
  27         libusb_device_handle *found = NULL;
  28         libusb_device **list;
  29         ssize_t cnt = libusb_get_device_list(ctx, &list);
  30         ssize_t i = 0;
  31
  32         if (cnt < 0){
  33                 return NULL;
  34         }
  35
  36         for(i = 0; i < cnt; i++) {
  37                 int err = 0;
  38                 libusb_device *device = list[i];
  39                 struct libusb_device_descriptor desc;
  40                 libusb_device_handle *handle;
  41                 err = libusb_open(device, &handle);
  42                 if (err)
  43                         continue;
  44
  45                 int r = libusb_get_device_descriptor( device, &desc );
  46                 if (r) {
  47                         libusb_close(handle);
  48                         continue;
  49                 }
  50
  51                 if ( desc.idVendor == vendor && desc.idProduct == product &&
  52                      ncusb_match_string(handle, desc.iManufacturer, vendor_name) &&
  53                      ncusb_match_string(handle, desc.iProduct,      product_name) &&
  54                      ncusb_match_string(handle, desc.iSerialNumber, serial)
  55                         )
  56                 {
  57                         found = handle;
  58                 }
  59
  60                 if (found)
  61                         break;
  62
  63         }
  64         libusb_free_device_list(list, 1);
  65
  66         return found;
  67 }
  68
  69
  70 void check_handle(libusb_device_handle **h, int vid, int pid, const char* manuf, const char* product, const char* serial)
  71 {
  72         if (*h)
  73                 return;
  74         libusb_init(NULL);
  75         libusb_set_debug(NULL, LIBUSB_LOG_LEVEL_WARNING);
  76         *h = ncusb_find_and_open(NULL, vid, pid, manuf, product, serial);
  77         if (!(*h)) {
  78                 fprintf(stderr, "No PL2303 USB device %04x:%04x found ;(\n", vid, pid);
  79                 exit(1);
  80         }
  81 }