add CCID driver (Werner Koch)

git-svn-id: https://svn.gnumonks.org/trunk/librfid@1594 e0336214-984f-0b4b-a45f-81c69e1f0ede

2 files changed, 2555 insertions, 0 deletions

diff --git a/ccid/ccid-driver.c b/ccid/ccid-driver.c
new file mode 100644
index 0000000..7b024b4
--- /dev/null
+++ b/ccid/ccid-driver.c
@@ -0,0 +1,2447 @@
+/* ccid-driver.c - USB ChipCardInterfaceDevices driver
+ *	Copyright (C) 2003, 2004, 2005 Free Software Foundation, Inc.
+ *      Written by Werner Koch.
+ *
+ * This file is part of GnuPG.
+ *
+ * GnuPG is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * GnuPG is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
+ * USA.
+ *
+ * ALTERNATIVELY, this file may be distributed under the terms of the
+ * following license, in which case the provisions of this license are
+ * required INSTEAD OF the GNU General Public License. If you wish to
+ * allow use of your version of this file only under the terms of the
+ * GNU General Public License, and not to allow others to use your
+ * version of this file under the terms of the following license,
+ * indicate your decision by deleting this paragraph and the license
+ * below.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, and the entire permission notice in its entirety,
+ *    including the disclaimer of warranties.
+ * 2. 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.
+ * 3. The name of the author may not be used to endorse or promote
+ *    products derived from this software without specific prior
+ *    written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED ``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 AUTHOR 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.
+ *
+ * $Date: 2005-09-09 13:18:08 +0200 (Fri, 09 Sep 2005) $
+ */
+
+
+/* CCID (ChipCardInterfaceDevices) is a specification for accessing
+   smartcard via a reader connected to the USB.  
+
+   This is a limited driver allowing to use some CCID drivers directly
+   without any other specila drivers. This is a fallback driver to be
+   used when nothing else works or the system should be kept minimal
+   for security reasons.  It makes use of the libusb library to gain
+   portable access to USB.
+
+   This driver has been tested with the SCM SCR335 and SPR532
+   smartcard readers and requires that a reader implements the TPDU
+   level exchange and does fully automatic initialization.
+*/
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#if defined(HAVE_LIBUSB) || defined(TEST)
+
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <assert.h>
+
+#include <usb.h>
+
+#include "ccid-driver.h"
+
+#define DRVNAME "ccid-driver: "
+
+
+/* Depending on how this source is used we either define our error
+   output to go to stderr or to the jnlib based logging functions.  We
+   use the latter when GNUPG_MAJOR_VERSION is defines or when both,
+   GNUPG_SCD_MAIN_HEADER and HAVE_JNLIB_LOGGING are defined.
+*/
+#if defined(GNUPG_MAJOR_VERSION) \
+    || (defined(GNUPG_SCD_MAIN_HEADER) && defined(HAVE_JNLIB_LOGGING))
+
+#if defined(GNUPG_SCD_MAIN_HEADER)
+#  include GNUPG_SCD_MAIN_HEADER
+#elif GNUPG_MAJOR_VERSION == 1 /* GnuPG Version is < 1.9. */
+#  include "options.h"
+#  include "util.h"
+#  include "memory.h"
+#  include "cardglue.h"
+# else /* This is the modularized GnuPG 1.9 or later. */
+#  include "scdaemon.h"
+#endif
+
+
+# define DEBUGOUT(t)         do { if (debug_level) \
+                                  log_debug (DRVNAME t); } while (0)
+# define DEBUGOUT_1(t,a)     do { if (debug_level) \
+                                  log_debug (DRVNAME t,(a)); } while (0)
+# define DEBUGOUT_2(t,a,b)   do { if (debug_level) \
+                                  log_debug (DRVNAME t,(a),(b)); } while (0)
+# define DEBUGOUT_3(t,a,b,c) do { if (debug_level) \
+                                  log_debug (DRVNAME t,(a),(b),(c));} while (0)
+# define DEBUGOUT_4(t,a,b,c,d) do { if (debug_level) \
+                              log_debug (DRVNAME t,(a),(b),(c),(d));} while (0)
+# define DEBUGOUT_CONT(t)    do { if (debug_level) \
+                                  log_printf (t); } while (0)
+# define DEBUGOUT_CONT_1(t,a)  do { if (debug_level) \
+                                  log_printf (t,(a)); } while (0)
+# define DEBUGOUT_CONT_2(t,a,b)   do { if (debug_level) \
+                                  log_printf (t,(a),(b)); } while (0)
+# define DEBUGOUT_CONT_3(t,a,b,c) do { if (debug_level) \
+                                  log_printf (t,(a),(b),(c)); } while (0)
+# define DEBUGOUT_LF()       do { if (debug_level) \
+                                  log_printf ("\n"); } while (0)
+
+#else /* Other usage of this source - don't use gnupg specifics. */
+
+# define DEBUGOUT(t)          do { if (debug_level) \
+                     fprintf (stderr, DRVNAME t); } while (0)
+# define DEBUGOUT_1(t,a)      do { if (debug_level) \
+                     fprintf (stderr, DRVNAME t, (a)); } while (0)
+# define DEBUGOUT_2(t,a,b)    do { if (debug_level) \
+                     fprintf (stderr, DRVNAME t, (a), (b)); } while (0)
+# define DEBUGOUT_3(t,a,b,c)  do { if (debug_level) \
+                     fprintf (stderr, DRVNAME t, (a), (b), (c)); } while (0)
+# define DEBUGOUT_4(t,a,b,c,d)  do { if (debug_level) \
+                     fprintf (stderr, DRVNAME t, (a), (b), (c), (d));} while(0)
+# define DEBUGOUT_CONT(t)     do { if (debug_level) \
+                     fprintf (stderr, t); } while (0)
+# define DEBUGOUT_CONT_1(t,a) do { if (debug_level) \
+                     fprintf (stderr, t, (a)); } while (0)
+# define DEBUGOUT_CONT_2(t,a,b) do { if (debug_level) \
+                     fprintf (stderr, t, (a), (b)); } while (0)
+# define DEBUGOUT_CONT_3(t,a,b,c) do { if (debug_level) \
+                     fprintf (stderr, t, (a), (b), (c)); } while (0)
+# define DEBUGOUT_LF()        do { if (debug_level) \
+                     putc ('\n', stderr); } while (0)
+
+#endif /* This source not used by scdaemon. */
+
+
+
+enum {
+  RDR_to_PC_NotifySlotChange= 0x50,
+  RDR_to_PC_HardwareError   = 0x51,
+
+  PC_to_RDR_SetParameters   = 0x61,
+  PC_to_RDR_IccPowerOn      = 0x62,
+  PC_to_RDR_IccPowerOff     = 0x63,
+  PC_to_RDR_GetSlotStatus   = 0x65,
+  PC_to_RDR_Secure          = 0x69,
+  PC_to_RDR_T0APDU          = 0x6a,
+  PC_to_RDR_Escape          = 0x6b,
+  PC_to_RDR_GetParameters   = 0x6c,
+  PC_to_RDR_ResetParameters = 0x6d,
+  PC_to_RDR_IccClock        = 0x6e,
+  PC_to_RDR_XfrBlock        = 0x6f,
+  PC_to_RDR_Mechanical      = 0x71,
+  PC_to_RDR_Abort           = 0x72,
+  PC_to_RDR_SetDataRate     = 0x73,
+
+  RDR_to_PC_DataBlock       = 0x80,
+  RDR_to_PC_SlotStatus      = 0x81,
+  RDR_to_PC_Parameters      = 0x82,
+  RDR_to_PC_Escape          = 0x83,
+  RDR_to_PC_DataRate        = 0x84
+};
+
+
+/* Two macro to detect whether a CCID command has failed and to get
+   the error code.  These macros assume that we can access the
+   mandatory first 10 bytes of a CCID message in BUF. */
+#define CCID_COMMAND_FAILED(buf) ((buf)[7] & 0x40)
+#define CCID_ERROR_CODE(buf)     (((unsigned char *)(buf))[8])
+
+
+/* We need to know the vendor to do some hacks. */
+enum {
+  VENDOR_SCM    = 0x04e6,
+  VENDOR_CHERRY = 0x046a,
+  VENDOR_GEMPC  = 0x08e6
+};
+
+
+/* Store information on the driver's state.  A pointer to such a
+   structure is used as handle for most functions. */
+struct ccid_driver_s 
+{
+  usb_dev_handle *idev;
+  char *rid;
+  unsigned short id_vendor;
+  unsigned short id_product;
+  unsigned short bcd_device;
+  int ifc_no;
+  int ep_bulk_out;
+  int ep_bulk_in;
+  int ep_intr;
+  int seqno;
+  unsigned char t1_ns;
+  unsigned char t1_nr;
+  int nonnull_nad;
+  int auto_ifsd;
+  int max_ifsd;
+  int ifsd;
+  int powered_off;
+  int has_pinpad;
+  int apdu_level;     /* Reader supports short APDU level exchange.  */
+};
+
+
+static int initialized_usb; /* Tracks whether USB has been initialized. */
+static int debug_level;     /* Flag to control the debug output. 
+                               0 = No debugging
+                               1 = USB I/O info
+                               2 = T=1 protocol tracing
+                              */
+
+
+static unsigned int compute_edc (const unsigned char *data, size_t datalen,
+                                 int use_crc);
+static int bulk_out (ccid_driver_t handle, unsigned char *msg, size_t msglen);
+static int bulk_in (ccid_driver_t handle, unsigned char *buffer, size_t length,
+                    size_t *nread, int expected_type, int seqno, int timeout,
+                    int no_debug);
+
+/* Convert a little endian stored 4 byte value into an unsigned
+   integer. */
+static unsigned int 
+convert_le_u32 (const unsigned char *buf)
+{
+  return buf[0] | (buf[1] << 8) | (buf[2] << 16) | (buf[3] << 24); 
+}
+
+static void
+set_msg_len (unsigned char *msg, unsigned int length)
+{
+  msg[1] = length;
+  msg[2] = length >> 8;
+  msg[3] = length >> 16;
+  msg[4] = length >> 24;
+}
+
+
+/* Pint an error message for a failed CCID command including a textual
+   error code.  MSG is shall be the CCID message of at least 10 bytes. */
+static void
+print_command_failed (const unsigned char *msg)
+{
+  const char *t;
+  char buffer[100];
+  int ec;
+
+  if (!debug_level)
+    return;
+
+  ec = CCID_ERROR_CODE (msg);
+  switch (ec)
+    {
+    case 0x00: t = "Command not supported"; break;
+    
+    case 0xE0: t = "Slot busy"; break;
+    case 0xEF: t = "PIN cancelled"; break;
+    case 0xF0: t = "PIN timeout"; break;
+
+    case 0xF2: t = "Automatic sequence ongoing"; break;
+    case 0xF3: t = "Deactivated Protocol"; break;
+    case 0xF4: t = "Procedure byte conflict"; break;
+    case 0xF5: t = "ICC class not supported"; break;
+    case 0xF6: t = "ICC protocol not supported"; break;
+    case 0xF7: t = "Bad checksum in ATR"; break;
+    case 0xF8: t = "Bad TS in ATR"; break;
+
+    case 0xFB: t = "An all inclusive hardware error occurred"; break;
+    case 0xFC: t = "Overrun error while talking to the ICC"; break;
+    case 0xFD: t = "Parity error while talking to the ICC"; break;
+    case 0xFE: t = "CCID timed out while talking to the ICC"; break;
+    case 0xFF: t = "Host aborted the current activity"; break;
+
+    default:
+      if (ec > 0 && ec < 128)
+        sprintf (buffer, "Parameter error at offset %d", ec);
+      else
+        sprintf (buffer, "Error code %02X", ec);
+      t = buffer;
+      break;
+    }
+  DEBUGOUT_1 ("CCID command failed: %s\n", t);
+}
+  
+
+
+
+/* Parse a CCID descriptor, optionally print all available features
+   and test whether this reader is usable by this driver.  Returns 0
+   if it is usable.
+
+   Note, that this code is based on the one in lsusb.c of the
+   usb-utils package, I wrote on 2003-09-01. -wk. */
+static int
+parse_ccid_descriptor (ccid_driver_t handle,
+                       const unsigned char *buf, size_t buflen)
+{
+  unsigned int i;
+  unsigned int us;
+  int have_t1 = 0, have_tpdu=0, have_auto_conf = 0;
+
+
+  handle->nonnull_nad = 0;
+  handle->auto_ifsd = 0;
+  handle->max_ifsd = 32;
+  handle->ifsd = 0;
+  handle->has_pinpad = 0;
+  handle->apdu_level = 0;
+  DEBUGOUT_3 ("idVendor: %04X  idProduct: %04X  bcdDevice: %04X\n",
+              handle->id_vendor, handle->id_product, handle->bcd_device);
+  if (buflen < 54 || buf[0] < 54)
+    {
+      DEBUGOUT ("CCID device descriptor is too short\n");
+      return -1;
+    }
+
+  DEBUGOUT   ("ChipCard Interface Descriptor:\n");
+  DEBUGOUT_1 ("  bLength             %5u\n", buf[0]);
+  DEBUGOUT_1 ("  bDescriptorType     %5u\n", buf[1]);
+  DEBUGOUT_2 ("  bcdCCID             %2x.%02x", buf[3], buf[2]);
+    if (buf[3] != 1 || buf[2] != 0) 
+      DEBUGOUT_CONT("  (Warning: Only accurate for version 1.0)");
+  DEBUGOUT_LF ();
+
+  DEBUGOUT_1 ("  nMaxSlotIndex       %5u\n", buf[4]);
+  DEBUGOUT_2 ("  bVoltageSupport     %5u  %s\n",
+              buf[5], (buf[5] == 1? "5.0V" : buf[5] == 2? "3.0V"
+                       : buf[5] == 3? "1.8V":"?"));
+
+  us = convert_le_u32 (buf+6);
+  DEBUGOUT_1 ("  dwProtocols         %5u ", us);
+  if ((us & 1))
+    DEBUGOUT_CONT (" T=0");
+  if ((us & 2))
+    {
+      DEBUGOUT_CONT (" T=1");
+      have_t1 = 1;
+    }
+  if ((us & ~3))
+    DEBUGOUT_CONT (" (Invalid values detected)");
+  DEBUGOUT_LF ();
+
+  us = convert_le_u32(buf+10);
+  DEBUGOUT_1 ("  dwDefaultClock      %5u\n", us);
+  us = convert_le_u32(buf+14);
+  DEBUGOUT_1 ("  dwMaxiumumClock     %5u\n", us);
+  DEBUGOUT_1 ("  bNumClockSupported  %5u\n", buf[18]);
+  us = convert_le_u32(buf+19);
+  DEBUGOUT_1 ("  dwDataRate        %7u bps\n", us);
+  us = convert_le_u32(buf+23);
+  DEBUGOUT_1 ("  dwMaxDataRate     %7u bps\n", us);
+  DEBUGOUT_1 ("  bNumDataRatesSupp.  %5u\n", buf[27]);
+        
+  us = convert_le_u32(buf+28);
+  DEBUGOUT_1 ("  dwMaxIFSD           %5u\n", us);
+  handle->max_ifsd = us;
+
+  us = convert_le_u32(buf+32);
+  DEBUGOUT_1 ("  dwSyncProtocols  %08X ", us);
+  if ((us&1))
+    DEBUGOUT_CONT ( " 2-wire");
+  if ((us&2))
+    DEBUGOUT_CONT ( " 3-wire");
+  if ((us&4))
+    DEBUGOUT_CONT ( " I2C");
+  DEBUGOUT_LF ();
+
+  us = convert_le_u32(buf+36);
+  DEBUGOUT_1 ("  dwMechanical     %08X ", us);
+  if ((us & 1))
+    DEBUGOUT_CONT (" accept");
+  if ((us & 2))
+    DEBUGOUT_CONT (" eject");
+  if ((us & 4))
+    DEBUGOUT_CONT (" capture");
+  if ((us & 8))
+    DEBUGOUT_CONT (" lock");
+  DEBUGOUT_LF ();
+
+  us = convert_le_u32(buf+40);
+  DEBUGOUT_1 ("  dwFeatures       %08X\n", us);
+  if ((us & 0x0002))
+    {
+      DEBUGOUT ("    Auto configuration based on ATR\n");
+      have_auto_conf = 1;
+    }
+  if ((us & 0x0004))
+    DEBUGOUT ("    Auto activation on insert\n");
+  if ((us & 0x0008))
+    DEBUGOUT ("    Auto voltage selection\n");
+  if ((us & 0x0010))
+    DEBUGOUT ("    Auto clock change\n");
+  if ((us & 0x0020))
+    DEBUGOUT ("    Auto baud rate change\n");
+  if ((us & 0x0040))
+    DEBUGOUT ("    Auto parameter negotation made by CCID\n");
+  else if ((us & 0x0080))
+    DEBUGOUT ("    Auto PPS made by CCID\n");
+  else if ((us & (0x0040 | 0x0080)))
+    DEBUGOUT ("    WARNING: conflicting negotation features\n");
+
+  if ((us & 0x0100))
+    DEBUGOUT ("    CCID can set ICC in clock stop mode\n");
+  if ((us & 0x0200))
+    {
+      DEBUGOUT ("    NAD value other than 0x00 accepted\n");
+      handle->nonnull_nad = 1;
+    }
+  if ((us & 0x0400))
+    {
+      DEBUGOUT ("    Auto IFSD exchange\n");
+      handle->auto_ifsd = 1;
+    }
+
+  if ((us & 0x00010000))
+    {
+      DEBUGOUT ("    TPDU level exchange\n");
+      have_tpdu = 1;
+    } 
+  else if ((us & 0x00020000))
+    {
+      DEBUGOUT ("    Short APDU level exchange\n");
+      handle->apdu_level = 1;
+    }
+  else if ((us & 0x00040000))
+    {
+      DEBUGOUT ("    Short and extended APDU level exchange\n");
+      handle->apdu_level = 1;
+    }
+  else if ((us & 0x00070000))
+    DEBUGOUT ("    WARNING: conflicting exchange levels\n");
+
+  us = convert_le_u32(buf+44);
+  DEBUGOUT_1 ("  dwMaxCCIDMsgLen     %5u\n", us);
+
+  DEBUGOUT (  "  bClassGetResponse    ");
+  if (buf[48] == 0xff)
+    DEBUGOUT_CONT ("echo\n");
+  else
+    DEBUGOUT_CONT_1 ("  %02X\n", buf[48]);
+
+  DEBUGOUT (  "  bClassEnvelope       ");
+  if (buf[49] == 0xff)
+    DEBUGOUT_CONT ("echo\n");
+  else
+    DEBUGOUT_CONT_1 ("  %02X\n", buf[48]);
+
+  DEBUGOUT (  "  wlcdLayout           ");
+  if (!buf[50] && !buf[51])
+    DEBUGOUT_CONT ("none\n");
+  else
+    DEBUGOUT_CONT_2 ("%u cols %u lines\n", buf[50], buf[51]);
+        
+  DEBUGOUT_1 ("  bPINSupport         %5u ", buf[52]);
+  if ((buf[52] & 1))
+    {
+      DEBUGOUT_CONT ( " verification");
+      handle->has_pinpad |= 1;
+    }
+  if ((buf[52] & 2))
+    {
+      DEBUGOUT_CONT ( " modification");
+      handle->has_pinpad |= 2;
+    }
+  DEBUGOUT_LF ();
+        
+  DEBUGOUT_1 ("  bMaxCCIDBusySlots   %5u\n", buf[53]);
+
+  if (buf[0] > 54) {
+    DEBUGOUT ("  junk             ");
+    for (i=54; i < buf[0]-54; i++)
+      DEBUGOUT_CONT_1 (" %02X", buf[i]);
+    DEBUGOUT_LF ();
+  }
+
+  if (!have_t1 || !(have_tpdu  || handle->apdu_level) || !have_auto_conf)
+    {
+      DEBUGOUT ("this drivers requires that the reader supports T=1, "
+                "TPDU or APDU level exchange and auto configuration - "
+                "this is not available\n");
+      return -1;
+    }
+
+
+  /* SCM drivers get stuck in their internal USB stack if they try to
+     send a frame of n*wMaxPacketSize back to us.  Given that
+     wMaxPacketSize is 64 for these readers we set the IFSD to a value
+     lower than that:
+        64 - 10 CCID header -  4 T1frame - 2 reserved = 48
+     Product Ids:
+	 0xe001 - SCR 331 
+	 0x5111 - SCR 331-DI 
+	 0x5115 - SCR 335 
+	 0xe003 - SPR 532 
+  */
+  if (handle->id_vendor == VENDOR_SCM
+      && handle->max_ifsd > 48      
+      && (  (handle->id_product == 0xe001 && handle->bcd_device < 0x0516)
+          ||(handle->id_product == 0x5111 && handle->bcd_device < 0x0620)
+          ||(handle->id_product == 0x5115 && handle->bcd_device < 0x0514)
+          ||(handle->id_product == 0xe003 && handle->bcd_device < 0x0504)
+          ))
+    {
+      DEBUGOUT ("enabling workaround for buggy SCM readers\n");
+      handle->max_ifsd = 48;
+    }
+
+
+  return 0;
+}
+
+
+static char *
+get_escaped_usb_string (usb_dev_handle *idev, int idx,
+                        const char *prefix, const char *suffix)
+{
+  int rc;
+  unsigned char buf[280];
+  unsigned char *s;
+  unsigned int langid;
+  size_t i, n, len;
+  char *result;
+
+  if (!idx)
+    return NULL;
+
+  /* Fixme: The next line is for the current Valgrid without support
+     for USB IOCTLs. */
+  memset (buf, 0, sizeof buf);
+
+  /* First get the list of supported languages and use the first one.
+     If we do don't find it we try to use English.  Note that this is
+     all in a 2 bute Unicode encoding using little endian. */
+  rc = usb_control_msg (idev, USB_ENDPOINT_IN, USB_REQ_GET_DESCRIPTOR,
+                        (USB_DT_STRING << 8), 0, 
+                        (char*)buf, sizeof buf, 1000 /* ms timeout */);
+  if (rc < 4)
+    langid = 0x0409; /* English.  */
+  else
+    langid = (buf[3] << 8) | buf[2];
+
+  rc = usb_control_msg (idev, USB_ENDPOINT_IN, USB_REQ_GET_DESCRIPTOR,
+                        (USB_DT_STRING << 8) + idx, langid,
+                        (char*)buf, sizeof buf, 1000 /* ms timeout */);
+  if (rc < 2 || buf[1] != USB_DT_STRING)
+    return NULL; /* Error or not a string. */
+  len = buf[0];
+  if (len > rc)
+    return NULL; /* Larger than our buffer. */
+
+  for (s=buf+2, i=2, n=0; i+1 < len; i += 2, s += 2)
+    {
+      if (s[1])
+        n++; /* High byte set. */
+      else if (*s <= 0x20 || *s >= 0x7f || *s == '%' || *s == ':')
+        n += 3 ;
+      else 
+        n++;
+    }
+
+  result = malloc (strlen (prefix) + n + strlen (suffix) + 1);
+  if (!result)
+    return NULL;
+
+  strcpy (result, prefix);
+  n = strlen (prefix);
+  for (s=buf+2, i=2; i+1 < len; i += 2, s += 2)
+    {
+      if (s[1])
+        result[n++] = '\xff'; /* High byte set. */
+      else if (*s <= 0x20 || *s >= 0x7f || *s == '%' || *s == ':')
+        {
+          sprintf (result+n, "%%%02X", *s);
+          n += 3;
+        }
+      else 
+        result[n++] = *s;
+    }
+  strcpy (result+n, suffix);
+
+  return result;
+}
+
+/* This function creates an reader id to be used to find the same
+   physical reader after a reset.  It returns an allocated and possibly
+   percent escaped string or NULL if not enough memory is available. */
+static char *
+make_reader_id (usb_dev_handle *idev,
+                unsigned int vendor, unsigned int product,
+                unsigned char serialno_index)
+{
+  char *rid;
+  char prefix[20];
+
+  sprintf (prefix, "%04X:%04X:", (vendor & 0xfff), (product & 0xffff));
+  rid = get_escaped_usb_string (idev, serialno_index, prefix, ":0");
+  if (!rid)
+    {
+      rid = malloc (strlen (prefix) + 3 + 1);
+      if (!rid)
+        return NULL;
+      strcpy (rid, prefix);
+      strcat (rid, "X:0");
+    }
+  return rid;
+}
+
+
+/* Helper to find the endpoint from an interface descriptor.  */
+static int
+find_endpoint (struct usb_interface_descriptor *ifcdesc, int mode)
+{
+  int no;
+  int want_bulk_in = 0;
+
+  if (mode == 1)
+    want_bulk_in = 0x80;
+  for (no=0; no < ifcdesc->bNumEndpoints; no++)
+    {
+      struct usb_endpoint_descriptor *ep = ifcdesc->endpoint + no;
+      if (ep->bDescriptorType != USB_DT_ENDPOINT)
+        ;
+      else if (mode == 2
+          && ((ep->bmAttributes & USB_ENDPOINT_TYPE_MASK)
+              == USB_ENDPOINT_TYPE_INTERRUPT)
+          && (ep->bEndpointAddress & 0x80))
+        return (ep->bEndpointAddress & 0x0f);
+      else if (((ep->bmAttributes & USB_ENDPOINT_TYPE_MASK)
+                == USB_ENDPOINT_TYPE_BULK)
+               && (ep->bEndpointAddress & 0x80) == want_bulk_in)
+        return (ep->bEndpointAddress & 0x0f);
+    }
+  /* Should never happen.  */
+  return mode == 2? 0x83 : mode == 1? 0x82 :1;
+}
+
+
+
+/* Combination function to either scan all CCID devices or to find and
+   open one specific device. 
+
+   With READERNO = -1 and READERID is NULL, scan mode is used and
+   R_RID should be the address where to store the list of reader_ids
+   we found.  If on return this list is empty, no CCID device has been
+   found; otherwise it points to an allocated linked list of reader
+   IDs.  Note that in this mode the function always returns NULL.
+
+   With READERNO >= 0 or READERID is not NULL find mode is used.  This
+   uses the same algorithm as the scan mode but stops and returns at
+   the entry number READERNO and return the handle for the the opened
+   USB device. If R_ID is not NULL it will receive the reader ID of
+   that device.  If R_DEV is not NULL it will the device pointer of
+   that device.  If IFCDESC_EXTRA is NOT NULL it will receive a
+   malloced copy of the interfaces "extra: data filed;
+   IFCDESC_EXTRA_LEN receive the lengtyh of this field.  If there is
+   no reader with number READERNO or that reader is not usable by our
+   implementation NULL will be returned.  The caller must close a
+   returned USB device handle and free (if not passed as NULL) the
+   returned reader ID info as well as the IFCDESC_EXTRA.  On error
+   NULL will get stored at R_RID, R_DEV, IFCDESC_EXTRA and
+   IFCDESC_EXTRA_LEN.  With READERID being -1 the function stops if
+   the READERID was found.
+
+   Note that the first entry of the returned reader ID list in scan mode
+   corresponds with a READERNO of 0 in find mode.
+*/
+static usb_dev_handle *
+scan_or_find_devices (int readerno, const char *readerid,
+                      char **r_rid,
+                      struct usb_device **r_dev,
+                      unsigned char **ifcdesc_extra,
+                      size_t *ifcdesc_extra_len,
+                      int *interface_number,
+                      int *ep_bulk_out, int *ep_bulk_in, int *ep_intr)
+{
+  char *rid_list = NULL;
+  int count = 0;
+  struct usb_bus *busses, *bus;
+  struct usb_device *dev = NULL;
+  usb_dev_handle *idev = NULL;
+  int scan_mode = (readerno == -1 && !readerid);
+
+   /* Set return values to a default. */
+  if (r_rid)
+    *r_rid = NULL;
+  if (r_dev)
+    *r_dev = NULL; 
+  if (ifcdesc_extra)
+    *ifcdesc_extra = NULL;
+  if (ifcdesc_extra_len)
+    *ifcdesc_extra_len = 0;
+  if (interface_number)
+    *interface_number = 0;
+
+  /* See whether we want scan or find mode. */
+  if (scan_mode) 
+    {
+      assert (r_rid);
+    }
+
+  usb_find_busses();
+  usb_find_devices();
+
+#ifdef HAVE_USB_GET_BUSSES
+  busses = usb_get_busses();
+#else
+  busses = usb_busses;
+#endif
+
+  for (bus = busses; bus; bus = bus->next) 
+    {
+      for (dev = bus->devices; dev; dev = dev->next)
+        {
+          int cfg_no;
+          
+          for (cfg_no=0; cfg_no < dev->descriptor.bNumConfigurations; cfg_no++)
+            {
+              struct usb_config_descriptor *config = dev->config + cfg_no;
+              int ifc_no;
+
+              if(!config)
+                continue;
+
+              for (ifc_no=0; ifc_no < config->bNumInterfaces; ifc_no++)
+                {
+                  struct usb_interface *interface
+                    = config->interface + ifc_no;
+                  int set_no;
+                  
+                  if (!interface)
+                    continue;
+                  
+                  for (set_no=0; set_no < interface->num_altsetting; set_no++)
+                    {
+                      struct usb_interface_descriptor *ifcdesc
+                        = interface->altsetting + set_no;
+                      char *rid;
+                      
+                      /* The second condition is for some SCM Micro
+                         SPR 532 which does not know about the
+                         assigned CCID class. Instead of trying to
+                         interpret the strings we simply look at the
+                         product ID. */
+                      if (ifcdesc && ifcdesc->extra
+                          && (   (ifcdesc->bInterfaceClass == 11
+                                  && ifcdesc->bInterfaceSubClass == 0
+                                  && ifcdesc->bInterfaceProtocol == 0)
+                              || (ifcdesc->bInterfaceClass == 255
+                                  && dev->descriptor.idVendor == 0x04e6
+                                  && dev->descriptor.idProduct == 0xe003)))
+                        {
+                          idev = usb_open (dev);
+                          if (!idev)
+                            {
+                              DEBUGOUT_1 ("usb_open failed: %s\n",
+                                          strerror (errno));
+                              continue;
+                            }
+                              
+                          rid = make_reader_id (idev,
+                                                dev->descriptor.idVendor,
+                                                dev->descriptor.idProduct,
+                                                dev->descriptor.iSerialNumber);
+                          if (rid)
+                            {
+                              if (scan_mode)
+                                {
+                                  char *p;
+
+                                  /* We are collecting infos about all
+                                     available CCID readers.  Store
+                                     them and continue. */
+                                  DEBUGOUT_2 ("found CCID reader %d "
+                                              "(ID=%s)\n",
+                                              count, rid );
+                                  if ((p = malloc ((rid_list?
+                                                    strlen (rid_list):0)
+                                                   + 1 + strlen (rid)
+                                                   + 1)))
+                                    {
+                                      *p = 0;
+                                      if (rid_list)
+                                        {
+                                          strcat (p, rid_list);
+                                          free (rid_list);
+                                        }
+                                      strcat (p, rid);
+                                      strcat (p, "\n");
+                                      rid_list = p;
+                                    }
+                                  else /* Out of memory. */
+                                    free (rid);
+                                  rid = NULL;
+                                  count++;
+                                }
+                              else if (!readerno
+                                       || (readerno < 0
+                                           && readerid
+                                           && !strcmp (readerid, rid)))
+                                {
+                                  /* We found the requested reader. */
+                                  if (ifcdesc_extra && ifcdesc_extra_len)
+                                    {
+                                      *ifcdesc_extra = malloc (ifcdesc
+                                                               ->extralen);
+                                      if (!*ifcdesc_extra)
+                                        {
+                                          usb_close (idev);
+                                          free (rid);
+                                          return NULL; /* Out of core. */
+                                        }
+                                      memcpy (*ifcdesc_extra, ifcdesc->extra,
+                                              ifcdesc->extralen);
+                                      *ifcdesc_extra_len = ifcdesc->extralen;
+                                    }
+                                  if (interface_number)
+                                    *interface_number = (ifcdesc->
+                                                         bInterfaceNumber);
+                                  if (ep_bulk_out)
+                                    *ep_bulk_out = find_endpoint (ifcdesc, 0);
+                                  if (ep_bulk_in)
+                                    *ep_bulk_in = find_endpoint (ifcdesc, 1);
+                                  if (ep_intr)
+                                    *ep_intr = find_endpoint (ifcdesc, 2);
+
+
+                                  if (r_dev)
+                                    *r_dev = dev;
+                                  if (r_rid)
+                                    {
+                                      *r_rid = rid;
+                                      rid = NULL;
+                                    }
+                                  else
+                                    free (rid);
+                                  return idev; /* READY. */
+                                }
+                              else
+                                {
+                                  /* This is not yet the reader we
+                                     want.  fixme: We could avoid the
+                                     extra usb_open in this case. */
+                                  if (readerno >= 0)
+                                    readerno--;
+                                }
+                              free (rid);
+                            }
+                          
+                          usb_close (idev);
+                          idev = NULL;
+                          goto next_device;
+                        }
+                    }
+                }
+            }
+        next_device:
+          ;
+        }
+    }
+
+  if (scan_mode)
+    *r_rid = rid_list;
+
+  return NULL;
+}
+
+
+/* Set the level of debugging to to usea dn return the old level.  -1
+   just returns the old level.  A level of 0 disables debugging, 1
+   enables debugging, 2 enables additional tracing of the T=1
+   protocol, other values are not yet defined. */
+int
+ccid_set_debug_level (int level)
+{
+  int old = debug_level;
+  if (level != -1)
+    debug_level = level;
+  return old;
+}
+
+
+char *
+ccid_get_reader_list (void)
+{
+  char *reader_list;
+
+  if (!initialized_usb)
+    {
+      usb_init ();
+      initialized_usb = 1;
+    }
+
+  scan_or_find_devices (-1, NULL, &reader_list, NULL, NULL, NULL, NULL,
+                        NULL, NULL, NULL);
+  return reader_list;
+}
+
+
+/* Open the reader with the internal number READERNO and return a 
+   pointer to be used as handle in HANDLE.  Returns 0 on success. */
+int 
+ccid_open_reader (ccid_driver_t *handle, const char *readerid)
+{
+  int rc = 0;
+  struct usb_device *dev = NULL;
+  usb_dev_handle *idev = NULL;
+  char *rid = NULL;
+  unsigned char *ifcdesc_extra = NULL;
+  size_t ifcdesc_extra_len;
+  int readerno;
+  int ifc_no, ep_bulk_out, ep_bulk_in, ep_intr;
+
+  *handle = NULL;
+
+  if (!initialized_usb)
+    {
+      usb_init ();
+      initialized_usb = 1;
+    }
+
+  /* See whether we want to use the reader ID string or a reader
+     number. A readerno of -1 indicates that the reader ID string is
+     to be used. */
+  if (readerid && strchr (readerid, ':'))
+    readerno = -1; /* We want to use the readerid.  */
+  else if (readerid)
+    {
+      readerno = atoi (readerid);
+      if (readerno < 0)
+        {
+          DEBUGOUT ("no CCID readers found\n");
+          rc = CCID_DRIVER_ERR_NO_READER;
+          goto leave;
+        }
+    }
+  else
+    readerno = 0;  /* Default. */
+
+  idev = scan_or_find_devices (readerno, readerid, &rid, &dev,
+                               &ifcdesc_extra, &ifcdesc_extra_len,
+                               &ifc_no, &ep_bulk_out, &ep_bulk_in, &ep_intr);
+  if (!idev)
+    {
+      if (readerno == -1)
+        DEBUGOUT_1 ("no CCID reader with ID %s\n", readerid );
+      else
+        DEBUGOUT_1 ("no CCID reader with number %d\n", readerno );
+      rc = CCID_DRIVER_ERR_NO_READER;
+      goto leave;
+    }
+
+  /* Okay, this is a CCID reader. */
+  *handle = calloc (1, sizeof **handle);
+  if (!*handle)
+    {
+      DEBUGOUT ("out of memory\n");
+      rc = CCID_DRIVER_ERR_OUT_OF_CORE;
+      goto leave;
+    }
+  (*handle)->idev = idev;
+  (*handle)->rid = rid;
+  (*handle)->id_vendor = dev->descriptor.idVendor;
+  (*handle)->id_product = dev->descriptor.idProduct;
+  (*handle)->bcd_device = dev->descriptor.bcdDevice;
+  (*handle)->ifc_no = ifc_no;
+  (*handle)->ep_bulk_out = ep_bulk_out;
+  (*handle)->ep_bulk_in = ep_bulk_in;
+  (*handle)->ep_intr = ep_intr;
+
+  DEBUGOUT_2 ("using CCID reader %d (ID=%s)\n",  readerno, rid );
+
+
+  if (parse_ccid_descriptor (*handle, ifcdesc_extra, ifcdesc_extra_len))
+    {
+      DEBUGOUT ("device not supported\n");
+      rc = CCID_DRIVER_ERR_NO_READER;
+      goto leave;
+    }
+  
+  rc = usb_claim_interface (idev, ifc_no);
+  if (rc)
+    {
+      DEBUGOUT_1 ("usb_claim_interface failed: %d\n", rc);
+      rc = CCID_DRIVER_ERR_CARD_IO_ERROR;
+      goto leave;
+    }
+  
+ leave:
+  free (ifcdesc_extra);
+  if (rc)
+    {
+      free (rid);
+      if (idev)
+        usb_close (idev);
+      free (*handle);
+      *handle = NULL;
+    }
+
+  return rc;
+}
+
+
+static void
+do_close_reader (ccid_driver_t handle)
+{
+  int rc;
+  unsigned char msg[100];
+  size_t msglen;
+  unsigned char seqno;
+  
+  if (!handle->powered_off)
+    {
+      msg[0] = PC_to_RDR_IccPowerOff;
+      msg[5] = 0; /* slot */
+      msg[6] = seqno = handle->seqno++;
+      msg[7] = 0; /* RFU */
+      msg[8] = 0; /* RFU */
+      msg[9] = 0; /* RFU */
+      set_msg_len (msg, 0);
+      msglen = 10;
+      
+      rc = bulk_out (handle, msg, msglen);
+      if (!rc)
+        bulk_in (handle, msg, sizeof msg, &msglen, RDR_to_PC_SlotStatus,
+                 seqno, 2000, 0);
+      handle->powered_off = 1;
+    }
+  if (handle->idev)
+    {
+      usb_release_interface (handle->idev, handle->ifc_no);
+      usb_close (handle->idev);
+      handle->idev = NULL;
+    }
+}
+
+
+/* Reset a reader on HANDLE.  This is useful in case a reader has been
+   plugged of and inserted at a different port.  By resetting the
+   handle, the same reader will be get used.  Note, that on error the
+   handle won't get released. 
+
+   This does not return an ATR, so ccid_get_atr should be called right
+   after this one.
+*/
+int 
+ccid_shutdown_reader (ccid_driver_t handle)
+{
+  int rc = 0;
+  struct usb_device *dev = NULL;
+  usb_dev_handle *idev = NULL;
+  unsigned char *ifcdesc_extra = NULL;
+  size_t ifcdesc_extra_len;
+  int ifc_no, ep_bulk_out, ep_bulk_in, ep_intr;
+
+  if (!handle || !handle->rid)
+    return CCID_DRIVER_ERR_INV_VALUE;
+
+  do_close_reader (handle);
+
+  idev = scan_or_find_devices (-1, handle->rid, NULL, &dev,
+                               &ifcdesc_extra, &ifcdesc_extra_len,
+                               &ifc_no, &ep_bulk_out, &ep_bulk_in, &ep_intr);
+  if (!idev)
+    {
+      DEBUGOUT_1 ("no CCID reader with ID %s\n", handle->rid);
+      return CCID_DRIVER_ERR_NO_READER;
+    }
+
+
+  handle->idev = idev;
+  handle->ifc_no = ifc_no;
+  handle->ep_bulk_out = ep_bulk_out;
+  handle->ep_bulk_in = ep_bulk_in;
+  handle->ep_intr = ep_intr;
+
+  if (parse_ccid_descriptor (handle, ifcdesc_extra, ifcdesc_extra_len))
+    {
+      DEBUGOUT ("device not supported\n");
+      rc = CCID_DRIVER_ERR_NO_READER;
+      goto leave;
+    }
+  
+  rc = usb_claim_interface (idev, ifc_no);
+  if (rc)
+    {
+      DEBUGOUT_1 ("usb_claim_interface failed: %d\n", rc);
+      rc = CCID_DRIVER_ERR_CARD_IO_ERROR;
+      goto leave;
+    }
+  
+ leave:
+  free (ifcdesc_extra);
+  if (rc)
+    {
+      usb_close (handle->idev);
+      handle->idev = NULL;
+    }
+
+  return rc;
+
+}
+
+
+/* Close the reader HANDLE. */
+int 
+ccid_close_reader (ccid_driver_t handle)
+{
+  if (!handle || !handle->idev)
+    return 0;
+
+  do_close_reader (handle);
+  free (handle->rid);
+  free (handle);
+  return 0;
+}
+
+
+/* Return False if a card is present and powered. */
+int
+ccid_check_card_presence (ccid_driver_t handle)
+{
+
+  return -1;
+}
+
+
+/* Write a MSG of length MSGLEN to the designated bulk out endpoint.
+   Returns 0 on success. */
+static int
+bulk_out (ccid_driver_t handle, unsigned char *msg, size_t msglen)
+{
+  int rc;
+
+  rc = usb_bulk_write (handle->idev, 
+                       handle->ep_bulk_out,
+                       (char*)msg, msglen,
+                       1000 /* ms timeout */);
+  if (rc == msglen)
+    return 0;
+
+  if (rc == -1)
+    DEBUGOUT_1 ("usb_bulk_write error: %s\n", strerror (errno));
+  else
+    DEBUGOUT_1 ("usb_bulk_write failed: %d\n", rc);
+  return CCID_DRIVER_ERR_CARD_IO_ERROR;
+}
+
+
+/* Read a maximum of LENGTH bytes from the bulk in endpoint into
+   BUFFER and return the actual read number if bytes in NREAD. SEQNO
+   is the sequence number used to send the request and EXPECTED_TYPE
+   the type of message we expect. Does checks on the ccid
+   header. TIMEOUT is the timeout value in ms. NO_DEBUG may be set to
+   avoid debug messages in case of no error. Returns 0 on success. */
+static int
+bulk_in (ccid_driver_t handle, unsigned char *buffer, size_t length,
+         size_t *nread, int expected_type, int seqno, int timeout,
+         int no_debug)
+{
+  int i, rc;
+  size_t msglen;
+
+  /* Fixme: The next line for the current Valgrind without support
+     for USB IOCTLs. */
+  memset (buffer, 0, length);
+ retry:
+  rc = usb_bulk_read (handle->idev, 
+                      handle->ep_bulk_in,
+                      (char*)buffer, length,
+                      timeout);
+  if (rc < 0)
+    {
+      DEBUGOUT_1 ("usb_bulk_read error: %s\n", strerror (errno));
+      return CCID_DRIVER_ERR_CARD_IO_ERROR;
+    }
+
+  *nread = msglen = rc;
+
+  if (msglen < 10)
+    {
+      DEBUGOUT_1 ("bulk-in msg too short (%u)\n", (unsigned int)msglen);
+      return CCID_DRIVER_ERR_INV_VALUE;
+    }
+  if (buffer[0] != expected_type)
+    {
+      DEBUGOUT_1 ("unexpected bulk-in msg type (%02x)\n", buffer[0]);
+      return CCID_DRIVER_ERR_INV_VALUE;
+    }
+  if (buffer[5] != 0)    
+    {
+      DEBUGOUT_1 ("unexpected bulk-in slot (%d)\n", buffer[5]);
+      return CCID_DRIVER_ERR_INV_VALUE;
+    }
+  if (buffer[6] != seqno)    
+    {
+      DEBUGOUT_2 ("bulk-in seqno does not match (%d/%d)\n",
+                  seqno, buffer[6]);
+      return CCID_DRIVER_ERR_INV_VALUE;
+    }
+
+  if ( !(buffer[7] & 0x03) && (buffer[7] & 0xC0) == 0x80)
+    { 
+      /* Card present and active, time extension requested. */
+      DEBUGOUT_2 ("time extension requested (%02X,%02X)\n",
+                  buffer[7], buffer[8]);
+      goto retry;
+    }
+
+  if (!no_debug)
+    {
+      DEBUGOUT_3 ("status: %02X  error: %02X  octet[9]: %02X\n"
+                  "               data:",  buffer[7], buffer[8], buffer[9] );
+      for (i=10; i < msglen; i++)
+        DEBUGOUT_CONT_1 (" %02X", buffer[i]);
+      DEBUGOUT_LF ();
+    }
+  if (CCID_COMMAND_FAILED (buffer))
+    print_command_failed (buffer);
+
+  /* Check whether a card is at all available.  Note: If you add new
+     error codes here, check whether they need to be ignored in
+     send_escape_cmd. */
+  switch ((buffer[7] & 0x03))
+    {
+    case 0: /* no error */ break;
+    case 1: return CCID_DRIVER_ERR_CARD_INACTIVE;
+    case 2: return CCID_DRIVER_ERR_NO_CARD;
+    case 3: /* RFU */ break;
+    }
+  return 0;
+}
+
+
+/* Note that this function won't return the error codes NO_CARD or
+   CARD_INACTIVE.  IF RESULT is not NULL, the result from the
+   operation will get returned in RESULT and its length in RESULTLEN.
+   If the response is larger than RESULTMAX, an error is returned and
+   the required buffer length returned in RESULTLEN.  */
+static int 
+send_escape_cmd (ccid_driver_t handle,
+                 const unsigned char *data, size_t datalen,
+                 unsigned char *result, size_t resultmax, size_t *resultlen)
+{
+  int i, rc;
+  unsigned char msg[100];
+  size_t msglen;
+  unsigned char seqno;
+
+  if (resultlen)
+    *resultlen = 0;
+
+  if (datalen > sizeof msg - 10)
+    return CCID_DRIVER_ERR_INV_VALUE; /* Escape data too large.  */
+
+  msg[0] = PC_to_RDR_Escape;
+  msg[5] = 0; /* slot */
+  msg[6] = seqno = handle->seqno++;
+  msg[7] = 0; /* RFU */
+  msg[8] = 0; /* RFU */
+  msg[9] = 0; /* RFU */
+  memcpy (msg+10, data, datalen);
+  msglen = 10 + datalen;
+  set_msg_len (msg, datalen);
+
+  DEBUGOUT ("sending");
+  for (i=0; i < msglen; i++)
+    DEBUGOUT_CONT_1 (" %02X", msg[i]);
+  DEBUGOUT_LF ();
+  rc = bulk_out (handle, msg, msglen);
+  if (rc)
+    return rc;
+  rc = bulk_in (handle, msg, sizeof msg, &msglen, RDR_to_PC_Escape,
+                seqno, 5000, 0);
+  if (result)
+    switch (rc)
+      {
+        /* We need to ignore certain errorcode here. */
+      case 0:
+      case CCID_DRIVER_ERR_CARD_INACTIVE:
+      case CCID_DRIVER_ERR_NO_CARD:
+        {
+          if (msglen > resultmax)
+            rc = CCID_DRIVER_ERR_INV_VALUE; /* Response too large. */
+          else
+            {
+              memcpy (result, msg, msglen);
+              *resultlen = msglen;
+            }
+          rc = 0;
+        }
+        break;
+      default:
+        break;
+      }
+  
+  return rc;
+}
+
+
+int
+ccid_transceive_escape (ccid_driver_t handle,
+                        const unsigned char *data, size_t datalen,
+                        unsigned char *resp, size_t maxresplen, size_t *nresp)
+{
+  return send_escape_cmd (handle, data, datalen, resp, maxresplen, nresp);
+}
+
+
+
+/* experimental */
+int
+ccid_poll (ccid_driver_t handle)
+{
+  int rc;
+  unsigned char msg[10];
+  size_t msglen;
+  int i, j;
+
+  rc = usb_bulk_read (handle->idev, 
+                      handle->ep_intr,
+                      (char*)msg, sizeof msg,
+                      0 /* ms timeout */ );
+  if (rc < 0 && errno == ETIMEDOUT)
+    return 0;
+
+  if (rc < 0)
+    {
+      DEBUGOUT_1 ("usb_intr_read error: %s\n", strerror (errno));
+      return CCID_DRIVER_ERR_CARD_IO_ERROR;
+    }
+
+  msglen = rc;
+  rc = 0;
+
+  if (msglen < 1)
+    {
+      DEBUGOUT ("intr-in msg too short\n");
+      return CCID_DRIVER_ERR_INV_VALUE;
+    }
+
+  if (msg[0] == RDR_to_PC_NotifySlotChange)
+    {
+      DEBUGOUT ("notify slot change:");
+      for (i=1; i < msglen; i++)
+        for (j=0; j < 4; j++)
+          DEBUGOUT_CONT_3 (" %d:%c%c",
+                           (i-1)*4+j, 
+                           (msg[i] & (1<<(j*2)))? 'p':'-',
+                           (msg[i] & (2<<(j*2)))? '*':' ');
+      DEBUGOUT_LF ();
+    }
+  else if (msg[0] == RDR_to_PC_HardwareError)    
+    {
+      DEBUGOUT ("hardware error occured\n");
+    }
+  else
+    {
+      DEBUGOUT_1 ("unknown intr-in msg of type %02X\n", msg[0]);
+    }
+
+  return 0;
+}
+
+
+/* Note that this fucntion won't return the error codes NO_CARD or
+   CARD_INACTIVE */
+int 
+ccid_slot_status (ccid_driver_t handle, int *statusbits)
+{
+  int rc;
+  unsigned char msg[100];
+  size_t msglen;
+  unsigned char seqno;
+  int retries = 0;
+
+ retry:
+  msg[0] = PC_to_RDR_GetSlotStatus;
+  msg[5] = 0; /* slot */
+  msg[6] = seqno = handle->seqno++;
+  msg[7] = 0; /* RFU */
+  msg[8] = 0; /* RFU */
+  msg[9] = 0; /* RFU */
+  set_msg_len (msg, 0);
+
+  rc = bulk_out (handle, msg, 10);
+  if (rc)
+    return rc;
+  /* Note that we set the NO_DEBUG flag here, so that the logs won't
+     get cluttered up by a ticker function checking for the slot
+     status and debugging enabled. */
+  rc = bulk_in (handle, msg, sizeof msg, &msglen, RDR_to_PC_SlotStatus,
+                seqno, retries? 1000 : 200, 1);
+  if (rc == CCID_DRIVER_ERR_CARD_IO_ERROR && retries < 3)
+    {
+      if (!retries)
+        {
+          DEBUGOUT ("USB: CALLING USB_CLEAR_HALT\n");
+          usb_clear_halt (handle->idev, handle->ep_bulk_in);
+          usb_clear_halt (handle->idev, handle->ep_bulk_out);
+        }
+      else
+          DEBUGOUT ("USB: RETRYING bulk_in AGAIN\n");
+      retries++;
+      goto retry;
+    }
+  if (rc && rc != CCID_DRIVER_ERR_NO_CARD
+      && rc != CCID_DRIVER_ERR_CARD_INACTIVE)
+    return rc;
+  *statusbits = (msg[7] & 3);
+
+  return 0;
+}
+
+
+int 
+ccid_get_atr (ccid_driver_t handle,
+              unsigned char *atr, size_t maxatrlen, size_t *atrlen)
+{
+  int rc;
+  int statusbits;
+  unsigned char msg[100];
+  unsigned char *tpdu;
+  size_t msglen, tpdulen;
+  unsigned char seqno;
+  int use_crc = 0;
+  unsigned int edc;
+  int i;
+  int tried_iso = 0;
+
+  /* First check whether a card is available.  */
+  rc = ccid_slot_status (handle, &statusbits);
+  if (rc)
+    return rc;
+  if (statusbits == 2)
+    return CCID_DRIVER_ERR_NO_CARD;
+
+  /* For an inactive and also for an active card, issue the PowerOn
+     command to get the ATR.  */
+ again:
+  msg[0] = PC_to_RDR_IccPowerOn;
+  msg[5] = 0; /* slot */
+  msg[6] = seqno = handle->seqno++;
+  msg[7] = 0; /* power select (0=auto, 1=5V, 2=3V, 3=1.8V) */
+  msg[8] = 0; /* RFU */
+  msg[9] = 0; /* RFU */
+  set_msg_len (msg, 0);
+  msglen = 10;
+
+  rc = bulk_out (handle, msg, msglen);
+  if (rc)
+    return rc;
+  rc = bulk_in (handle, msg, sizeof msg, &msglen, RDR_to_PC_DataBlock,
+                seqno, 5000, 0);
+  if (rc)
+    return rc;
+  if (!tried_iso && CCID_COMMAND_FAILED (msg) && CCID_ERROR_CODE (msg) == 0xbb
+      && ((handle->id_vendor == VENDOR_CHERRY
+           && handle->id_product == 0x0005)
+          || (handle->id_vendor == VENDOR_GEMPC
+              && handle->id_product == 0x4433)
+          ))
+    {
+      tried_iso = 1;
+      /* Try switching to ISO mode. */
+      if (!send_escape_cmd (handle, (const unsigned char*)"\xF1\x01", 2,
+                            NULL, 0, NULL))
+        goto again;
+    }
+  else if (CCID_COMMAND_FAILED (msg))
+    return CCID_DRIVER_ERR_CARD_IO_ERROR;
+
+
+  handle->powered_off = 0;
+  
+  if (atr)
+    {
+      size_t n = msglen - 10;
+
+      if (n > maxatrlen)
+        n = maxatrlen;
+      memcpy (atr, msg+10, n);
+      *atrlen = n;
+    }
+
+  /* Setup parameters to select T=1. */
+  msg[0] = PC_to_RDR_SetParameters;
+  msg[5] = 0; /* slot */
+  msg[6] = seqno = handle->seqno++;
+  msg[7] = 1; /* Select T=1. */
+  msg[8] = 0; /* RFU */
+  msg[9] = 0; /* RFU */
+
+  /* FIXME: Get those values from the ATR. */
+  msg[10]= 0x01; /* Fi/Di */
+  msg[11]= 0x10; /* LRC, direct convention. */
+  msg[12]= 0;    /* Extra guardtime. */
+  msg[13]= 0x41; /* BWI/CWI */
+  msg[14]= 0;    /* No clock stoppping. */
+  msg[15]= 254;  /* IFSC */
+  msg[16]= 0;    /* Does not support non default NAD values. */
+  set_msg_len (msg, 7);
+  msglen = 10 + 7;
+
+  DEBUGOUT ("sending");
+  for (i=0; i < msglen; i++)
+    DEBUGOUT_CONT_1 (" %02X", msg[i]);
+  DEBUGOUT_LF ();
+
+  rc = bulk_out (handle, msg, msglen);
+  if (rc)
+    return rc;
+  /* Note that we ignore the error code on purpose. */
+  bulk_in (handle, msg, sizeof msg, &msglen, RDR_to_PC_Parameters,
+           seqno, 5000, 0);
+
+  handle->t1_ns = 0;
+  handle->t1_nr = 0;
+
+  /* Send an S-Block with our maximun IFSD to the CCID.  */
+  if (!handle->auto_ifsd)
+    {
+      tpdu = msg+10;
+      /* NAD: DAD=1, SAD=0 */
+      tpdu[0] = handle->nonnull_nad? ((1 << 4) | 0): 0;
+      tpdu[1] = (0xc0 | 0 | 1); /* S-block request: change IFSD */
+      tpdu[2] = 1;
+      tpdu[3] = handle->max_ifsd? handle->max_ifsd : 32; 
+      tpdulen = 4;
+      edc = compute_edc (tpdu, tpdulen, use_crc);
+      if (use_crc)
+        tpdu[tpdulen++] = (edc >> 8);
+      tpdu[tpdulen++] = edc;
+
+      msg[0] = PC_to_RDR_XfrBlock;
+      msg[5] = 0; /* slot */
+      msg[6] = seqno = handle->seqno++;
+      msg[7] = 0; 
+      msg[8] = 0; /* RFU */
+      msg[9] = 0; /* RFU */
+      set_msg_len (msg, tpdulen);
+      msglen = 10 + tpdulen;
+
+      DEBUGOUT ("sending");
+      for (i=0; i < msglen; i++)
+        DEBUGOUT_CONT_1 (" %02X", msg[i]);
+      DEBUGOUT_LF ();
+
+      if (debug_level > 1)
+        DEBUGOUT_3 ("T=1: put %c-block seq=%d%s\n",
+                      ((msg[11] & 0xc0) == 0x80)? 'R' :
+                                (msg[11] & 0x80)? 'S' : 'I',
+                      ((msg[11] & 0x80)? !!(msg[11]& 0x10)
+                                       : !!(msg[11] & 0x40)),
+                    (!(msg[11] & 0x80) && (msg[11] & 0x20)? " [more]":""));
+
+      rc = bulk_out (handle, msg, msglen);
+      if (rc)
+        return rc;
+
+
+      rc = bulk_in (handle, msg, sizeof msg, &msglen,
+                    RDR_to_PC_DataBlock, seqno, 5000, 0);
+      if (rc)
+        return rc;
+      
+      tpdu = msg + 10;
+      tpdulen = msglen - 10;
+      
+      if (tpdulen < 4) 
+        return CCID_DRIVER_ERR_ABORTED; 
+
+      if (debug_level > 1)
+        DEBUGOUT_4 ("T=1: got %c-block seq=%d err=%d%s\n",
+                    ((msg[11] & 0xc0) == 0x80)? 'R' :
+                              (msg[11] & 0x80)? 'S' : 'I',
+                    ((msg[11] & 0x80)? !!(msg[11]& 0x10)
+                                     : !!(msg[11] & 0x40)),
+                    ((msg[11] & 0xc0) == 0x80)? (msg[11] & 0x0f) : 0,
+                    (!(msg[11] & 0x80) && (msg[11] & 0x20)? " [more]":""));
+
+      if ((tpdu[1] & 0xe0) != 0xe0 || tpdu[2] != 1)
+        {
+          DEBUGOUT ("invalid response for S-block (Change-IFSD)\n");
+          return -1;
+        }
+      DEBUGOUT_1 ("IFSD has been set to %d\n", tpdu[3]);
+    }
+
+  return 0;
+}
+
+
+
+
+static unsigned int 
+compute_edc (const unsigned char *data, size_t datalen, int use_crc)
+{
+  if (use_crc)
+    {
+      return 0x42; /* Not yet implemented. */
+    }
+  else
+    {
+      unsigned char crc = 0;
+      
+      for (; datalen; datalen--)
+        crc ^= *data++;
+      return crc;
+    }
+}
+
+
+/* Helper for ccid_transceive used for APDU level exchanges.  */
+static int
+ccid_transceive_apdu_level (ccid_driver_t handle,
+                            const unsigned char *apdu_buf, size_t apdu_buflen,
+                            unsigned char *resp, size_t maxresplen,
+                            size_t *nresp)
+{
+  int rc;
+  unsigned char send_buffer[10+259], recv_buffer[10+259];
+  const unsigned char *apdu;
+  size_t apdulen;
+  unsigned char *msg;
+  size_t msglen;
+  unsigned char seqno;
+  int i;
+
+  msg = send_buffer;
+
+  apdu = apdu_buf;
+  apdulen = apdu_buflen;
+  assert (apdulen);
+
+  if (apdulen > 254)
+    return CCID_DRIVER_ERR_INV_VALUE; /* Invalid length. */
+
+  msg[0] = PC_to_RDR_XfrBlock;
+  msg[5] = 0; /* slot */
+  msg[6] = seqno = handle->seqno++;
+  msg[7] = 4; /* bBWI */
+  msg[8] = 0; /* RFU */
+  msg[9] = 0; /* RFU */
+  memcpy (msg+10, apdu, apdulen);
+  set_msg_len (msg, apdulen);
+  msglen = 10 + apdulen;
+
+  DEBUGOUT ("sending");
+  for (i=0; i < msglen; i++)
+    DEBUGOUT_CONT_1 (" %02X", msg[i]);
+  DEBUGOUT_LF ();
+  
+  rc = bulk_out (handle, msg, msglen);
+  if (rc)
+    return rc;
+
+  msg = recv_buffer;
+  rc = bulk_in (handle, msg, sizeof recv_buffer, &msglen,
+                RDR_to_PC_DataBlock, seqno, 5000, 0);
+  if (rc)
+    return rc;
+      
+  apdu = msg + 10;
+  apdulen = msglen - 10;
+      
+  if (resp)
+    {
+      if (apdulen > maxresplen)
+        {
+          DEBUGOUT_2 ("provided buffer too short for received data "
+                      "(%u/%u)\n",
+                      (unsigned int)apdulen, (unsigned int)maxresplen);
+          return CCID_DRIVER_ERR_INV_VALUE;
+        }
+      
+      memcpy (resp, apdu, apdulen); 
+      *nresp = apdulen;
+    }
+          
+  return 0;
+}
+
+
+
+/*
+  Protocol T=1 overview
+
+  Block Structure:
+           Prologue Field:
+   1 byte     Node Address (NAD) 
+   1 byte     Protocol Control Byte (PCB)
+   1 byte     Length (LEN) 
+           Information Field:
+   0-254 byte APDU or Control Information (INF)
+           Epilogue Field:
+   1 byte     Error Detection Code (EDC)
+
+  NAD:  
+   bit 7     unused
+   bit 4..6  Destination Node Address (DAD)
+   bit 3     unused
+   bit 2..0  Source Node Address (SAD)
+
+   If node adresses are not used, SAD and DAD should be set to 0 on
+   the first block sent to the card.  If they are used they should
+   have different values (0 for one is okay); that first block sets up
+   the addresses of the nodes.
+
+  PCB:
+   Information Block (I-Block):
+      bit 7    0
+      bit 6    Sequence number (yep, that is modulo 2)
+      bit 5    Chaining flag 
+      bit 4..0 reserved
+   Received-Ready Block (R-Block):
+      bit 7    1
+      bit 6    0
+      bit 5    0
+      bit 4    Sequence number
+      bit 3..0  0 = no error
+                1 = EDC or parity error
+                2 = other error
+                other values are reserved
+   Supervisory Block (S-Block):
+      bit 7    1
+      bit 6    1
+      bit 5    clear=request,set=response
+      bit 4..0  0 = resyncronisation request
+                1 = information field size request
+                2 = abort request
+                3 = extension of BWT request
+                4 = VPP error
+                other values are reserved
+
+*/
+
+int
+ccid_transceive (ccid_driver_t handle,
+                 const unsigned char *apdu_buf, size_t apdu_buflen,
+                 unsigned char *resp, size_t maxresplen, size_t *nresp)
+{
+  int rc;
+  unsigned char send_buffer[10+259], recv_buffer[10+259];
+  const unsigned char *apdu;
+  size_t apdulen;
+  unsigned char *msg, *tpdu, *p;
+  size_t msglen, tpdulen, last_tpdulen, n;
+  unsigned char seqno;
+  int i;
+  unsigned int edc;
+  int use_crc = 0;
+  size_t dummy_nresp;
+  int next_chunk = 1;
+  int sending = 1;
+  int retries = 0;
+
+  if (!nresp)
+    nresp = &dummy_nresp;
+  *nresp = 0;
+
+  /* Smarter readers allow to send APDUs directly; divert here. */
+  if (handle->apdu_level)
+    return ccid_transceive_apdu_level (handle, apdu_buf, apdu_buflen,
+                                       resp, maxresplen, nresp);
+
+  /* The other readers we support require sending TPDUs.  */
+
+  tpdulen = 0; /* Avoid compiler warning about no initialization. */
+  msg = send_buffer;
+  for (;;)
+    {
+      if (next_chunk)
+        {
+          next_chunk = 0;
+
+          apdu = apdu_buf;
+          apdulen = apdu_buflen;
+          assert (apdulen);
+
+          /* Construct an I-Block. */
+          if (apdulen > 254)
+            return CCID_DRIVER_ERR_INV_VALUE; /* Invalid length. */
+
+          tpdu = msg+10;
+          /* NAD: DAD=1, SAD=0 */
+          tpdu[0] = handle->nonnull_nad? ((1 << 4) | 0): 0;
+          tpdu[1] = ((handle->t1_ns & 1) << 6); /* I-block */
+          if (apdulen > 128 /* fixme: replace by ifsc */)
+            {
+              apdulen = 128;
+              apdu_buf += 128;  
+              apdu_buflen -= 128;
+              tpdu[1] |= (1 << 5); /* Set more bit. */
+            }
+          tpdu[2] = apdulen;
+          memcpy (tpdu+3, apdu, apdulen);
+          tpdulen = 3 + apdulen;
+          edc = compute_edc (tpdu, tpdulen, use_crc);
+          if (use_crc)
+            tpdu[tpdulen++] = (edc >> 8);
+          tpdu[tpdulen++] = edc;
+        }
+
+      msg[0] = PC_to_RDR_XfrBlock;
+      msg[5] = 0; /* slot */
+      msg[6] = seqno = handle->seqno++;
+      msg[7] = 4; /* bBWI */
+      msg[8] = 0; /* RFU */
+      msg[9] = 0; /* RFU */
+      set_msg_len (msg, tpdulen);
+      msglen = 10 + tpdulen;
+      last_tpdulen = tpdulen;
+
+      DEBUGOUT ("sending");
+      for (i=0; i < msglen; i++)
+        DEBUGOUT_CONT_1 (" %02X", msg[i]);
+      DEBUGOUT_LF ();
+
+      if (debug_level > 1)
+          DEBUGOUT_3 ("T=1: put %c-block seq=%d%s\n",
+                      ((msg[11] & 0xc0) == 0x80)? 'R' :
+                                (msg[11] & 0x80)? 'S' : 'I',
+                      ((msg[11] & 0x80)? !!(msg[11]& 0x10)
+                                       : !!(msg[11] & 0x40)),
+                      (!(msg[11] & 0x80) && (msg[11] & 0x20)? " [more]":""));
+
+      rc = bulk_out (handle, msg, msglen);
+      if (rc)
+        return rc;
+
+      msg = recv_buffer;
+      rc = bulk_in (handle, msg, sizeof recv_buffer, &msglen,
+                    RDR_to_PC_DataBlock, seqno, 5000, 0);
+      if (rc)
+        return rc;
+      
+      tpdu = msg + 10;
+      tpdulen = msglen - 10;
+      
+      if (tpdulen < 4) 
+        {
+          usb_clear_halt (handle->idev, handle->ep_bulk_in);
+          return CCID_DRIVER_ERR_ABORTED; 
+        }
+
+      if (debug_level > 1)
+        DEBUGOUT_4 ("T=1: got %c-block seq=%d err=%d%s\n",
+                    ((msg[11] & 0xc0) == 0x80)? 'R' :
+                              (msg[11] & 0x80)? 'S' : 'I',
+                    ((msg[11] & 0x80)? !!(msg[11]& 0x10) : !!(msg[11] & 0x40)),
+                    ((msg[11] & 0xc0) == 0x80)? (msg[11] & 0x0f) : 0,
+                    (!(msg[11] & 0x80) && (msg[11] & 0x20)? " [more]":""));
+
+      if (!(tpdu[1] & 0x80))
+        { /* This is an I-block. */
+          retries = 0;
+          if (sending)
+            { /* last block sent was successful. */
+              handle->t1_ns ^= 1;
+              sending = 0;
+            }
+
+          if (!!(tpdu[1] & 0x40) != handle->t1_nr)
+            { /* Reponse does not match our sequence number. */
+              msg = send_buffer;
+              tpdu = msg+10;
+              /* NAD: DAD=1, SAD=0 */
+              tpdu[0] = handle->nonnull_nad? ((1 << 4) | 0): 0;
+              tpdu[1] = (0x80 | (handle->t1_nr & 1) << 4 | 2); /* R-block */
+              tpdu[2] = 0;
+              tpdulen = 3;
+              edc = compute_edc (tpdu, tpdulen, use_crc);
+              if (use_crc)
+                tpdu[tpdulen++] = (edc >> 8);
+              tpdu[tpdulen++] = edc;
+
+              continue;
+            }
+
+          handle->t1_nr ^= 1;
+
+          p = tpdu + 3; /* Skip the prologue field. */
+          n = tpdulen - 3 - 1; /* Strip the epilogue field. */
+          /* fixme: verify the checksum. */
+          if (resp)
+            {
+              if (n > maxresplen)
+                {
+                  DEBUGOUT_2 ("provided buffer too short for received data "
+                              "(%u/%u)\n",
+                              (unsigned int)n, (unsigned int)maxresplen);
+                  return CCID_DRIVER_ERR_INV_VALUE;
+                }
+              
+              memcpy (resp, p, n); 
+              resp += n;
+              *nresp += n;
+              maxresplen -= n;
+            }
+          
+          if (!(tpdu[1] & 0x20))
+            return 0; /* No chaining requested - ready. */
+          
+          msg = send_buffer;
+          tpdu = msg+10;
+          /* NAD: DAD=1, SAD=0 */
+          tpdu[0] = handle->nonnull_nad? ((1 << 4) | 0): 0;
+          tpdu[1] = (0x80 | (handle->t1_nr & 1) << 4); /* R-block */
+          tpdu[2] = 0;
+          tpdulen = 3;
+          edc = compute_edc (tpdu, tpdulen, use_crc);
+          if (use_crc)
+            tpdu[tpdulen++] = (edc >> 8);
+          tpdu[tpdulen++] = edc;
+        }
+      else if ((tpdu[1] & 0xc0) == 0x80)
+        { /* This is a R-block. */
+          if ( (tpdu[1] & 0x0f)) 
+            { /* Error: repeat last block */
+              if (++retries > 3)
+                {
+                  DEBUGOUT ("3 failed retries\n");
+                  return CCID_DRIVER_ERR_CARD_IO_ERROR;
+                }
+              msg = send_buffer;
+              tpdulen = last_tpdulen;
+            }
+          else if (sending && !!(tpdu[1] & 0x10) == handle->t1_ns)
+            { /* Response does not match our sequence number. */
+              DEBUGOUT ("R-block with wrong seqno received on more bit\n");
+              return CCID_DRIVER_ERR_CARD_IO_ERROR;
+            }
+          else if (sending)
+            { /* Send next chunk. */
+              retries = 0;
+              msg = send_buffer;
+              next_chunk = 1;
+              handle->t1_ns ^= 1;
+            }
+          else
+            {
+              DEBUGOUT ("unexpected ACK R-block received\n");
+              return CCID_DRIVER_ERR_CARD_IO_ERROR;
+            }
+        }
+      else 
+        { /* This is a S-block. */
+          retries = 0;
+          DEBUGOUT_2 ("T=1 S-block %s received cmd=%d\n",
+                      (tpdu[1] & 0x20)? "response": "request",
+                      (tpdu[1] & 0x1f));
+          if ( !(tpdu[1] & 0x20) && (tpdu[1] & 0x1f) == 3 && tpdu[2])
+            { /* Wait time extension request. */
+              unsigned char bwi = tpdu[3];
+              msg = send_buffer;
+              tpdu = msg+10;
+              /* NAD: DAD=1, SAD=0 */
+              tpdu[0] = handle->nonnull_nad? ((1 << 4) | 0): 0;
+              tpdu[1] = (0xc0 | 0x20 | 3); /* S-block response */
+              tpdu[2] = 1;
+              tpdu[3] = bwi;
+              tpdulen = 4;
+              edc = compute_edc (tpdu, tpdulen, use_crc);
+              if (use_crc)
+                tpdu[tpdulen++] = (edc >> 8);
+              tpdu[tpdulen++] = edc;
+              DEBUGOUT_1 ("T=1 waittime extension of bwi=%d\n", bwi);
+            }
+          else
+            return CCID_DRIVER_ERR_CARD_IO_ERROR;
+        }
+    } /* end T=1 protocol loop. */
+
+  return 0;
+}
+
+
+/* Send the CCID Secure command to the reader.  APDU_BUF should
+   contain the APDU template.  PIN_MODE defines how the pin gets
+   formatted:
+   
+     1 := The PIN is ASCII encoded and of variable length.  The
+          length of the PIN entered will be put into Lc by the reader.
+          The APDU should me made up of 4 bytes without Lc.
+
+   PINLEN_MIN and PINLEN_MAX define the limits for the pin length. 0
+   may be used t enable reasonable defaults.  PIN_PADLEN should be 0.
+   
+   When called with RESP and NRESP set to NULL, the function will
+   merely check whether the reader supports the secure command for the
+   given APDU and PIN_MODE. */
+int
+ccid_transceive_secure (ccid_driver_t handle,
+                        const unsigned char *apdu_buf, size_t apdu_buflen,
+                        int pin_mode, int pinlen_min, int pinlen_max,
+                        int pin_padlen, 
+                        unsigned char *resp, size_t maxresplen, size_t *nresp)
+{
+  int rc;
+  unsigned char send_buffer[10+259], recv_buffer[10+259];
+  unsigned char *msg, *tpdu, *p;
+  size_t msglen, tpdulen, n;
+  unsigned char seqno;
+  int i;
+  size_t dummy_nresp;
+  int testmode;
+
+  testmode = !resp && !nresp;
+
+  if (!nresp)
+    nresp = &dummy_nresp;
+  *nresp = 0;
+
+  if (apdu_buflen >= 4 && apdu_buf[1] == 0x20 && (handle->has_pinpad & 1))
+    ;
+  else if (apdu_buflen >= 4 && apdu_buf[1] == 0x24 && (handle->has_pinpad & 2))
+    return CCID_DRIVER_ERR_NOT_SUPPORTED; /* Not yet by our code. */
+  else
+    return CCID_DRIVER_ERR_NO_KEYPAD;
+    
+  if (pin_mode != 1)
+    return CCID_DRIVER_ERR_NOT_SUPPORTED;
+
+  if (pin_padlen != 0)
+    return CCID_DRIVER_ERR_NOT_SUPPORTED;
+
+  if (!pinlen_min)
+    pinlen_min = 1;
+  if (!pinlen_max)
+    pinlen_max = 25;
+
+  /* Note that the 25 is the maximum value the SPR532 allows.  */
+  if (pinlen_min < 1 || pinlen_min > 25
+      || pinlen_max < 1 || pinlen_max > 25 
+      || pinlen_min > pinlen_max)
+    return CCID_DRIVER_ERR_INV_VALUE;
+
+  /* We have only tested this with an SCM reader so better don't risk
+     anything and do not allow the use with other readers. */
+  if (handle->id_vendor != VENDOR_SCM)
+    return CCID_DRIVER_ERR_NOT_SUPPORTED;
+
+  if (testmode)
+    return 0; /* Success */
+    
+  msg = send_buffer;
+  if (handle->id_vendor == VENDOR_SCM)
+    {
+      DEBUGOUT ("sending escape sequence to switch to a case 1 APDU\n");
+      rc = send_escape_cmd (handle, (const unsigned char*)"\x80\x02\x00", 3,
+                            NULL, 0, NULL);
+      if (rc)
+        return rc;
+    }
+
+  msg[0] = PC_to_RDR_Secure;
+  msg[5] = 0; /* slot */
+  msg[6] = seqno = handle->seqno++;
+  msg[7] = 4; /* bBWI */
+  msg[8] = 0; /* RFU */
+  msg[9] = 0; /* RFU */
+  msg[10] = 0; /* Perform PIN verification. */
+  msg[11] = 0; /* Timeout in seconds. */
+  msg[12] = 0x82; /* bmFormatString: Byte, pos=0, left, ASCII. */
+  if (handle->id_vendor == VENDOR_SCM)
+    {
+      /* For the SPR532 the next 2 bytes need to be zero.  We do this
+         for all SCM product. Kudos to Martin Paljak for this
+         hint.  */
+      msg[13] = msg[14] = 0;
+    }
+  else
+    {
+      msg[13] = 0x00; /* bmPINBlockString:
+                         0 bits of pin length to insert. 
+                         0 bytes of PIN block size.  */
+      msg[14] = 0x00; /* bmPINLengthFormat:
+                         Units are bytes, position is 0. */
+    }
+  msg[15] = pinlen_min;   /* wPINMaxExtraDigit-Minimum.  */
+  msg[16] = pinlen_max;   /* wPINMaxExtraDigit-Maximum.  */
+  msg[17] = 0x02; /* bEntryValidationCondition:
+                     Validation key pressed */
+  if (pinlen_min && pinlen_max && pinlen_min == pinlen_max)
+    msg[17] |= 0x01; /* Max size reached.  */
+  msg[18] = 0xff; /* bNumberMessage: Default. */
+  msg[19] = 0x04; /* wLangId-High. */
+  msg[20] = 0x09; /* wLangId-Low:  English FIXME: use the first entry. */
+  msg[21] = 0;    /* bMsgIndex. */
+  /* bTeoProlog follows: */
+  msg[22] = handle->nonnull_nad? ((1 << 4) | 0): 0;
+  msg[23] = ((handle->t1_ns & 1) << 6); /* I-block */
+  msg[24] = 4; /* apdulen.  */
+  /* APDU follows:  */
+  msg[25] = apdu_buf[0]; /* CLA */
+  msg[26] = apdu_buf[1]; /* INS */
+  msg[27] = apdu_buf[2]; /* P1 */
+  msg[28] = apdu_buf[3]; /* P2 */
+  msglen = 29;
+  set_msg_len (msg, msglen - 10);
+
+  DEBUGOUT ("sending");
+  for (i=0; i < msglen; i++)
+    DEBUGOUT_CONT_1 (" %02X", msg[i]);
+  DEBUGOUT_LF ();
+  
+  rc = bulk_out (handle, msg, msglen);
+  if (rc)
+    return rc;
+  
+  msg = recv_buffer;
+  rc = bulk_in (handle, msg, sizeof recv_buffer, &msglen,
+                RDR_to_PC_DataBlock, seqno, 5000, 0);
+  if (rc)
+    return rc;
+  
+  tpdu = msg + 10;
+  tpdulen = msglen - 10;
+  
+  if (tpdulen < 4) 
+    {
+      usb_clear_halt (handle->idev, handle->ep_bulk_in);
+      return CCID_DRIVER_ERR_ABORTED; 
+    }
+  if (debug_level > 1)
+    DEBUGOUT_4 ("T=1: got %c-block seq=%d err=%d%s\n",
+                ((msg[11] & 0xc0) == 0x80)? 'R' :
+                          (msg[11] & 0x80)? 'S' : 'I',
+                ((msg[11] & 0x80)? !!(msg[11]& 0x10) : !!(msg[11] & 0x40)),
+                ((msg[11] & 0xc0) == 0x80)? (msg[11] & 0x0f) : 0,
+                (!(msg[11] & 0x80) && (msg[11] & 0x20)? " [more]":""));
+
+  if (!(tpdu[1] & 0x80))
+    { /* This is an I-block. */
+      /* Last block sent was successful. */
+      handle->t1_ns ^= 1;
+
+      if (!!(tpdu[1] & 0x40) != handle->t1_nr)
+        { /* Reponse does not match our sequence number. */
+          DEBUGOUT ("I-block with wrong seqno received\n");
+          return CCID_DRIVER_ERR_CARD_IO_ERROR;
+        }
+
+      handle->t1_nr ^= 1;
+
+      p = tpdu + 3; /* Skip the prologue field. */
+      n = tpdulen - 3 - 1; /* Strip the epilogue field. */
+      /* fixme: verify the checksum. */
+      if (resp)
+        {
+          if (n > maxresplen)
+            {
+              DEBUGOUT_2 ("provided buffer too short for received data "
+                          "(%u/%u)\n",
+                          (unsigned int)n, (unsigned int)maxresplen);
+              return CCID_DRIVER_ERR_INV_VALUE;
+            }
+              
+          memcpy (resp, p, n); 
+          resp += n;
+          *nresp += n;
+          maxresplen -= n;
+        }
+          
+      if (!(tpdu[1] & 0x20))
+        return 0; /* No chaining requested - ready. */
+      
+      DEBUGOUT ("chaining requested but not supported for Secure operation\n");
+      return CCID_DRIVER_ERR_CARD_IO_ERROR;
+    }
+  else if ((tpdu[1] & 0xc0) == 0x80)
+    { /* This is a R-block. */
+      if ( (tpdu[1] & 0x0f)) 
+        { /* Error: repeat last block */
+          DEBUGOUT ("No retries supported for Secure operation\n");
+          return CCID_DRIVER_ERR_CARD_IO_ERROR;
+        }
+      else if (!!(tpdu[1] & 0x10) == handle->t1_ns)
+        { /* Reponse does not match our sequence number. */
+          DEBUGOUT ("R-block with wrong seqno received on more bit\n");
+          return CCID_DRIVER_ERR_CARD_IO_ERROR;
+        }
+      else
+        { /* Send next chunk. */
+          DEBUGOUT ("chaining not supported on Secure operation\n");
+          return CCID_DRIVER_ERR_CARD_IO_ERROR;
+        }
+    }
+  else 
+    { /* This is a S-block. */
+      DEBUGOUT_2 ("T=1 S-block %s received cmd=%d for Secure operation\n",
+                  (tpdu[1] & 0x20)? "response": "request",
+                  (tpdu[1] & 0x1f));
+      return CCID_DRIVER_ERR_CARD_IO_ERROR;
+    } 
+
+  return 0;
+}
+
+
+
+
+#ifdef TEST
+
+
+static void
+print_error (int err)
+{
+  const char *p;
+  char buf[50];
+
+  switch (err)
+    {
+    case 0: p = "success";
+    case CCID_DRIVER_ERR_OUT_OF_CORE: p = "out of core"; break;
+    case CCID_DRIVER_ERR_INV_VALUE: p = "invalid value"; break;
+    case CCID_DRIVER_ERR_NO_DRIVER: p = "no driver"; break;
+    case CCID_DRIVER_ERR_NOT_SUPPORTED: p = "not supported"; break;
+    case CCID_DRIVER_ERR_LOCKING_FAILED: p = "locking failed"; break;
+    case CCID_DRIVER_ERR_BUSY: p = "busy"; break;
+    case CCID_DRIVER_ERR_NO_CARD: p = "no card"; break;
+    case CCID_DRIVER_ERR_CARD_INACTIVE: p = "card inactive"; break;
+    case CCID_DRIVER_ERR_CARD_IO_ERROR: p = "card I/O error"; break;
+    case CCID_DRIVER_ERR_GENERAL_ERROR: p = "general error"; break;
+    case CCID_DRIVER_ERR_NO_READER: p = "no reader"; break;
+    case CCID_DRIVER_ERR_ABORTED: p = "aborted"; break;
+    default: sprintf (buf, "0x%05x", err); p = buf; break;
+    }
+  fprintf (stderr, "operation failed: %s\n", p);
+}
+
+static void
+print_data (const unsigned char *data, size_t length)
+{
+  if (length >= 2)
+    {
+      fprintf (stderr, "operation status: %02X%02X\n",
+               data[length-2], data[length-1]);
+      length -= 2;
+    }
+  if (length)
+    {
+        fputs ("   returned data:", stderr);
+        for (; length; length--, data++)
+          fprintf (stderr, " %02X", *data);
+        putc ('\n', stderr);
+    }
+}
+
+static void
+print_result (int rc, const unsigned char *data, size_t length)
+{
+  if (rc)
+    print_error (rc);
+  else if (data)
+    print_data (data, length);
+}
+
+int
+main (int argc, char **argv)
+{
+  int rc;
+  ccid_driver_t ccid;
+  unsigned int slotstat;
+  unsigned char result[512];
+  size_t resultlen;
+  int no_pinpad = 0;
+  int verify_123456 = 0;
+  int did_verify = 0;
+  int no_poll = 0;
+
+  if (argc)
+    {
+      argc--;
+      argv++;
+    }
+
+  while (argc)
+    {
+      if ( !strcmp (*argv, "--list"))
+        {
+          char *p;
+          p = ccid_get_reader_list ();
+          if (!p)
+            return 1;
+          fputs (p, stderr);
+          free (p);
+          return 0;
+        }
+      else if ( !strcmp (*argv, "--debug"))
+        {
+          ccid_set_debug_level (1);
+          argc--; argv++;
+        }
+      else if ( !strcmp (*argv, "--no-poll"))
+        {
+          no_poll = 1;
+          argc--; argv++;
+        }
+      else if ( !strcmp (*argv, "--no-pinpad"))
+        {
+          no_pinpad = 1;
+          argc--; argv++;
+        }
+      else if ( !strcmp (*argv, "--verify-123456"))
+        {
+          verify_123456 = 1;
+          argc--; argv++;
+        }
+      else
+        break;
+    }
+
+  rc = ccid_open_reader (&ccid, argc? *argv:NULL);
+  if (rc)
+    return 1;
+
+  if (!no_poll)
+    ccid_poll (ccid);
+  fputs ("getting ATR ...\n", stderr);
+  rc = ccid_get_atr (ccid, NULL, 0, NULL);
+  if (rc)
+    {
+      print_error (rc);
+      return 1;
+    }
+
+  if (!no_poll)
+    ccid_poll (ccid);
+  fputs ("getting slot status ...\n", stderr);
+  rc = ccid_slot_status (ccid, &slotstat);
+  if (rc)
+    {
+      print_error (rc);
+      return 1;
+    }
+
+  if (!no_poll)
+    ccid_poll (ccid);
+
+  fputs ("selecting application OpenPGP ....\n", stderr);
+  {
+    static unsigned char apdu[] = {
+      0, 0xA4, 4, 0, 6, 0xD2, 0x76, 0x00, 0x01, 0x24, 0x01};
+    rc = ccid_transceive (ccid,
+                          apdu, sizeof apdu,
+                          result, sizeof result, &resultlen);
+    print_result (rc, result, resultlen);
+  }
+  
+
+  if (!no_poll)
+    ccid_poll (ccid);
+
+  fputs ("getting OpenPGP DO 0x65 ....\n", stderr);
+  {
+    static unsigned char apdu[] = { 0, 0xCA, 0, 0x65, 254 };
+    rc = ccid_transceive (ccid, apdu, sizeof apdu,
+                          result, sizeof result, &resultlen);
+    print_result (rc, result, resultlen);
+  }
+
+  if (!no_pinpad)
+    {
+    }
+
+  if (!no_pinpad)
+    {
+      static unsigned char apdu[] = { 0, 0x20, 0, 0x81 };
+
+      
+      if (ccid_transceive_secure (ccid,
+                                  apdu, sizeof apdu,
+                                  1, 0, 0, 0,
+                                  NULL, 0, NULL))
+        fputs ("can't verify using a PIN-Pad reader\n", stderr);
+      else
+        {
+          fputs ("verifying CHV1 using the PINPad ....\n", stderr);
+          
+          rc = ccid_transceive_secure (ccid,
+                                       apdu, sizeof apdu,
+                                       1, 0, 0, 0,
+                                       result, sizeof result, &resultlen);
+          print_result (rc, result, resultlen);
+          did_verify = 1;
+        }
+    }
+  
+  if (verify_123456 && !did_verify)
+    {
+      fputs ("verifying that CHV1 is 123456....\n", stderr);
+      {
+        static unsigned char apdu[] = {0, 0x20, 0, 0x81,
+                                       6, '1','2','3','4','5','6'};
+        rc = ccid_transceive (ccid, apdu, sizeof apdu,
+                              result, sizeof result, &resultlen);
+        print_result (rc, result, resultlen);
+      }
+    }
+
+  if (!rc)
+    {
+      fputs ("getting OpenPGP DO 0x5E ....\n", stderr);
+      {
+        static unsigned char apdu[] = { 0, 0xCA, 0, 0x5E, 254 };
+        rc = ccid_transceive (ccid, apdu, sizeof apdu,
+                              result, sizeof result, &resultlen);
+        print_result (rc, result, resultlen);
+      }
+    }
+
+  ccid_close_reader (ccid);
+
+  return 0;
+}
+
+/*
+ * Local Variables:
+ *  compile-command: "gcc -DTEST -Wall -I/usr/local/include -lusb -g ccid-driver.c"
+ * End:
+ */
+#endif /*TEST*/
+#endif /*HAVE_LIBUSB*/
diff --git a/ccid/ccid-driver.h b/ccid/ccid-driver.h
new file mode 100644
index 0000000..ae6b7fd
--- /dev/null
+++ b/ccid/ccid-driver.h
@@ -0,0 +1,108 @@
+/* ccid-driver.c - USB ChipCardInterfaceDevices driver
+ *	Copyright (C) 2003 Free Software Foundation, Inc.
+ *
+ * This file is part of GnuPG.
+ *
+ * GnuPG is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * GnuPG is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
+ * USA.
+ *
+ * ALTERNATIVELY, this file may be distributed under the terms of the
+ * following license, in which case the provisions of this license are
+ * required INSTEAD OF the GNU General Public License. If you wish to
+ * allow use of your version of this file only under the terms of the
+ * GNU General Public License, and not to allow others to use your
+ * version of this file under the terms of the following license,
+ * indicate your decision by deleting this paragraph and the license
+ * below.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, and the entire permission notice in its entirety,
+ *    including the disclaimer of warranties.
+ * 2. 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.
+ * 3. The name of the author may not be used to endorse or promote
+ *    products derived from this software without specific prior
+ *    written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED ``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 AUTHOR 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.
+ *
+ * $Id: ccid-driver.h 3887 2005-09-09 11:18:08Z wk $
+ */
+
+#ifndef CCID_DRIVER_H
+#define CCID_DRIVER_H
+
+/* The CID driver returns the same error codes as the status words
+   used by GnuPG's apdu.h.  For ease of maintenance they should always
+   match.  */
+#define CCID_DRIVER_ERR_OUT_OF_CORE    0x10001 
+#define CCID_DRIVER_ERR_INV_VALUE      0x10002
+#define CCID_DRIVER_ERR_INCOMPLETE_CARD_RESPONSE = 0x10003
+#define CCID_DRIVER_ERR_NO_DRIVER      0x10004
+#define CCID_DRIVER_ERR_NOT_SUPPORTED  0x10005
+#define CCID_DRIVER_ERR_LOCKING_FAILED 0x10006
+#define CCID_DRIVER_ERR_BUSY           0x10007
+#define CCID_DRIVER_ERR_NO_CARD        0x10008
+#define CCID_DRIVER_ERR_CARD_INACTIVE  0x10009
+#define CCID_DRIVER_ERR_CARD_IO_ERROR  0x1000a
+#define CCID_DRIVER_ERR_GENERAL_ERROR  0x1000b
+#define CCID_DRIVER_ERR_NO_READER      0x1000c
+#define CCID_DRIVER_ERR_ABORTED        0x1000d
+#define CCID_DRIVER_ERR_NO_KEYPAD      0x1000e
+
+struct ccid_driver_s;
+typedef struct ccid_driver_s *ccid_driver_t;
+
+int ccid_set_debug_level (int level);
+char *ccid_get_reader_list (void);
+int ccid_open_reader (ccid_driver_t *handle, const char *readerid);
+int ccid_shutdown_reader (ccid_driver_t handle);
+int ccid_close_reader (ccid_driver_t handle);
+int ccid_get_atr (ccid_driver_t handle,
+                  unsigned char *atr, size_t maxatrlen, size_t *atrlen);
+int ccid_slot_status (ccid_driver_t handle, int *statusbits);
+int ccid_transceive (ccid_driver_t handle,
+                     const unsigned char *apdu, size_t apdulen,
+                     unsigned char *resp, size_t maxresplen, size_t *nresp);
+int ccid_transceive_secure (ccid_driver_t handle,
+                     const unsigned char *apdu, size_t apdulen,
+                     int pin_mode, 
+                     int pinlen_min, int pinlen_max, int pin_padlen, 
+                     unsigned char *resp, size_t maxresplen, size_t *nresp);
+int ccid_transceive_escape (ccid_driver_t handle,
+                            const unsigned char *data, size_t datalen,
+                            unsigned char *resp, size_t maxresplen,
+                            size_t *nresp);
+
+
+
+#endif /*CCID_DRIVER_H*/
+
+
+