Adding upstream version 2.2.40.upstream/2.2.40

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 4080 insertions, 0 deletions

diff --git a/scd/ccid-driver.c b/scd/ccid-driver.c
new file mode 100644
index 0000000..214165f
--- /dev/null
+++ b/scd/ccid-driver.c
@@ -0,0 +1,4080 @@
+/* ccid-driver.c - USB ChipCardInterfaceDevices driver
+ * Copyright (C) 2003, 2004, 2005, 2006, 2007
+ *               2008, 2009, 2013  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 3 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, see <https://www.gnu.org/licenses/>.
+ *
+ * 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.
+ */
+
+
+/* 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 APDU or
+   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 <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <time.h>
+#include <unistd.h>
+#ifdef HAVE_NPTH
+# include <npth.h>
+#endif /*HAVE_NPTH*/
+
+#include <libusb.h>
+
+#include "scdaemon.h"
+#include "iso7816.h"
+#define CCID_DRIVER_INCLUDE_USB_IDS 1
+#include "ccid-driver.h"
+
+#define DRVNAME "ccid-driver: "
+
+/* Max length of buffer with out CCID message header of 10-byte
+   Sending: 547 for RSA-4096 key import
+        APDU size = 540 (24+4+256+256)
+        command + lc + le = 4 + 3 + 0
+   Sending: write data object of cardholder certificate
+        APDU size = 2048
+        command + lc + le = 4 + 3 + 0
+   Receiving: 2048 for cardholder certificate
+*/
+#define CCID_MAX_BUF (2048+7+10)
+
+/* CCID command timeout.  */
+#define CCID_CMD_TIMEOUT (5*1000)
+
+/* Number of supported devices.  See MAX_READER in apdu.c. */
+#define CCID_MAX_DEVICE 4
+
+
+/* Depending on how this source is used we either define our error
+   output to go to stderr or to the GnuPG based logging functions.  We
+   use the latter when GNUPG_MAJOR_VERSION or GNUPG_SCD_MAIN_HEADER
+   are defined.  */
+#if defined(GNUPG_MAJOR_VERSION) || defined(GNUPG_SCD_MAIN_HEADER)
+
+#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. */
+
+
+#ifndef EAGAIN
+#define EAGAIN  EWOULDBLOCK
+#endif
+
+
+
+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])
+
+
+/* Store information on the driver's state.  A pointer to such a
+   structure is used as handle for most functions. */
+struct ccid_driver_s
+{
+  libusb_device_handle *idev;
+  unsigned int bai;
+  unsigned short id_vendor;
+  unsigned short id_product;
+  int ifc_no;
+  int ep_bulk_out;
+  int ep_bulk_in;
+  int ep_intr;
+  int seqno;
+  unsigned char t1_ns;
+  unsigned char t1_nr;
+  unsigned char nonnull_nad;
+  int max_ifsd;
+  int max_ccid_msglen;
+  int ifsc;
+  unsigned char apdu_level:2;     /* Reader supports short APDU level
+                                     exchange.  With a value of 2 short
+                                     and extended level is supported.*/
+  unsigned int auto_voltage:1;
+  unsigned int auto_param:1;
+  unsigned int auto_pps:1;
+  unsigned int auto_ifsd:1;
+  unsigned int has_pinpad:2;
+  unsigned int enodev_seen:1;
+  int powered_off;
+
+  time_t last_progress; /* Last time we sent progress line.  */
+
+  /* The progress callback and its first arg as supplied to
+     ccid_set_progress_cb.  */
+  void (*progress_cb)(void *, const char *, int, int, int);
+  void *progress_cb_arg;
+
+  void (*prompt_cb)(void *, int);
+  void *prompt_cb_arg;
+
+  unsigned char intr_buf[64];
+  struct libusb_transfer *transfer;
+};
+
+
+/* Object to keep infos about found ccid devices.  */
+struct ccid_dev_table {
+  int n;                        /* Index to ccid_usb_dev_list */
+  int interface_number;
+  int setting_number;
+  unsigned char *ifcdesc_extra;
+  int ep_bulk_out;
+  int ep_bulk_in;
+  int ep_intr;
+  size_t ifcdesc_extra_len;
+};
+
+
+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 = Level 1 + T=1 protocol tracing
+                               3 = Level 2 + USB/I/O tracing of SlotStatus.
+                              */
+static int ccid_usb_thread_is_alive;
+
+static libusb_device **ccid_usb_dev_list;
+static struct ccid_dev_table ccid_dev_table[CCID_MAX_DEVICE];
+
+
+
+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,
+                     int no_debug);
+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);
+static int abort_cmd (ccid_driver_t handle, int seqno, int init);
+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);
+
+
+static int
+map_libusb_error (int usberr)
+{
+  switch (usberr)
+    {
+    case 0:                     return 0;
+    case LIBUSB_ERROR_IO:       return CCID_DRIVER_ERR_USB_IO;
+    case LIBUSB_ERROR_ACCESS:   return CCID_DRIVER_ERR_USB_ACCESS;
+    case LIBUSB_ERROR_NO_DEVICE:return CCID_DRIVER_ERR_USB_NO_DEVICE;
+    case LIBUSB_ERROR_BUSY:     return CCID_DRIVER_ERR_USB_BUSY;
+    case LIBUSB_ERROR_TIMEOUT:  return CCID_DRIVER_ERR_USB_TIMEOUT;
+    case LIBUSB_ERROR_OVERFLOW: return CCID_DRIVER_ERR_USB_OVERFLOW;
+    }
+  return CCID_DRIVER_ERR_USB_OTHER;
+}
+
+
+/* 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) | ((unsigned int)buf[3] << 24);
+}
+
+
+/* Convert a little endian stored 2 byte value into an unsigned
+   integer. */
+static unsigned int
+convert_le_u16 (const unsigned char *buf)
+{
+  return buf[0] | (buf[1] << 8);
+}
+
+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;
+}
+
+
+static void
+print_progress (ccid_driver_t handle)
+{
+  time_t ct = time (NULL);
+
+  /* We don't want to print progress lines too often. */
+  if (ct == handle->last_progress)
+    return;
+
+  if (handle->progress_cb)
+    handle->progress_cb (handle->progress_cb_arg, "card_busy", 'w', 0, 0);
+
+  handle->last_progress = ct;
+}
+
+
+
+/* Pint an error message for a failed CCID command including a textual
+   error code.  MSG shall be the CCID message at a minimum of 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);
+}
+
+
+static void
+print_pr_data (const unsigned char *data, size_t datalen, size_t off)
+{
+  int any = 0;
+
+  for (; off < datalen; off++)
+    {
+      if (!any || !(off % 16))
+        {
+          if (any)
+            DEBUGOUT_LF ();
+          DEBUGOUT_1 ("  [%04lu] ", (unsigned long) off);
+        }
+      DEBUGOUT_CONT_1 (" %02X", data[off]);
+      any = 1;
+    }
+  if (any && (off % 16))
+    DEBUGOUT_LF ();
+}
+
+
+static void
+print_p2r_header (const char *name, const unsigned char *msg, size_t msglen)
+{
+  DEBUGOUT_1 ("%s:\n", name);
+  if (msglen < 7)
+    return;
+  DEBUGOUT_1 ("  dwLength ..........: %u\n", convert_le_u32 (msg+1));
+  DEBUGOUT_1 ("  bSlot .............: %u\n", msg[5]);
+  DEBUGOUT_1 ("  bSeq ..............: %u\n", msg[6]);
+}
+
+
+static void
+print_p2r_iccpoweron (const unsigned char *msg, size_t msglen)
+{
+  print_p2r_header ("PC_to_RDR_IccPowerOn", msg, msglen);
+  if (msglen < 10)
+    return;
+  DEBUGOUT_2 ("  bPowerSelect ......: 0x%02x (%s)\n", msg[7],
+              msg[7] == 0? "auto":
+              msg[7] == 1? "5.0 V":
+              msg[7] == 2? "3.0 V":
+              msg[7] == 3? "1.8 V":"");
+  print_pr_data (msg, msglen, 8);
+}
+
+
+static void
+print_p2r_iccpoweroff (const unsigned char *msg, size_t msglen)
+{
+  print_p2r_header ("PC_to_RDR_IccPowerOff", msg, msglen);
+  print_pr_data (msg, msglen, 7);
+}
+
+
+static void
+print_p2r_getslotstatus (const unsigned char *msg, size_t msglen)
+{
+  print_p2r_header ("PC_to_RDR_GetSlotStatus", msg, msglen);
+  print_pr_data (msg, msglen, 7);
+}
+
+
+static void
+print_p2r_xfrblock (const unsigned char *msg, size_t msglen)
+{
+  unsigned int val;
+
+  print_p2r_header ("PC_to_RDR_XfrBlock", msg, msglen);
+  if (msglen < 10)
+    return;
+  DEBUGOUT_1 ("  bBWI ..............: 0x%02x\n", msg[7]);
+  val = convert_le_u16 (msg+8);
+  DEBUGOUT_2 ("  wLevelParameter ...: 0x%04x%s\n", val,
+              val == 1? " (continued)":
+              val == 2? " (continues+ends)":
+              val == 3? " (continues+continued)":
+              val == 16? " (DataBlock-expected)":"");
+  print_pr_data (msg, msglen, 10);
+}
+
+
+static void
+print_p2r_getparameters (const unsigned char *msg, size_t msglen)
+{
+  print_p2r_header ("PC_to_RDR_GetParameters", msg, msglen);
+  print_pr_data (msg, msglen, 7);
+}
+
+
+static void
+print_p2r_resetparameters (const unsigned char *msg, size_t msglen)
+{
+  print_p2r_header ("PC_to_RDR_ResetParameters", msg, msglen);
+  print_pr_data (msg, msglen, 7);
+}
+
+
+static void
+print_p2r_setparameters (const unsigned char *msg, size_t msglen)
+{
+  print_p2r_header ("PC_to_RDR_SetParameters", msg, msglen);
+  if (msglen < 10)
+    return;
+  DEBUGOUT_1 ("  bProtocolNum ......: 0x%02x\n", msg[7]);
+  print_pr_data (msg, msglen, 8);
+}
+
+
+static void
+print_p2r_escape (const unsigned char *msg, size_t msglen)
+{
+  print_p2r_header ("PC_to_RDR_Escape", msg, msglen);
+  print_pr_data (msg, msglen, 7);
+}
+
+
+static void
+print_p2r_iccclock (const unsigned char *msg, size_t msglen)
+{
+  print_p2r_header ("PC_to_RDR_IccClock", msg, msglen);
+  if (msglen < 10)
+    return;
+  DEBUGOUT_1 ("  bClockCommand .....: 0x%02x\n", msg[7]);
+  print_pr_data (msg, msglen, 8);
+}
+
+
+static void
+print_p2r_to0apdu (const unsigned char *msg, size_t msglen)
+{
+  print_p2r_header ("PC_to_RDR_T0APDU", msg, msglen);
+  if (msglen < 10)
+    return;
+  DEBUGOUT_1 ("  bmChanges .........: 0x%02x\n", msg[7]);
+  DEBUGOUT_1 ("  bClassGetResponse .: 0x%02x\n", msg[8]);
+  DEBUGOUT_1 ("  bClassEnvelope ....: 0x%02x\n", msg[9]);
+  print_pr_data (msg, msglen, 10);
+}
+
+
+static void
+print_p2r_secure (const unsigned char *msg, size_t msglen)
+{
+  unsigned int val;
+
+  print_p2r_header ("PC_to_RDR_Secure", msg, msglen);
+  if (msglen < 10)
+    return;
+  DEBUGOUT_1 ("  bBMI ..............: 0x%02x\n", msg[7]);
+  val = convert_le_u16 (msg+8);
+  DEBUGOUT_2 ("  wLevelParameter ...: 0x%04x%s\n", val,
+              val == 1? " (continued)":
+              val == 2? " (continues+ends)":
+              val == 3? " (continues+continued)":
+              val == 16? " (DataBlock-expected)":"");
+  print_pr_data (msg, msglen, 10);
+}
+
+
+static void
+print_p2r_mechanical (const unsigned char *msg, size_t msglen)
+{
+  print_p2r_header ("PC_to_RDR_Mechanical", msg, msglen);
+  if (msglen < 10)
+    return;
+  DEBUGOUT_1 ("  bFunction .........: 0x%02x\n", msg[7]);
+  print_pr_data (msg, msglen, 8);
+}
+
+
+static void
+print_p2r_abort (const unsigned char *msg, size_t msglen)
+{
+  print_p2r_header ("PC_to_RDR_Abort", msg, msglen);
+  print_pr_data (msg, msglen, 7);
+}
+
+
+static void
+print_p2r_setdatarate (const unsigned char *msg, size_t msglen)
+{
+  print_p2r_header ("PC_to_RDR_SetDataRate", msg, msglen);
+  if (msglen < 10)
+    return;
+  print_pr_data (msg, msglen, 7);
+}
+
+
+static void
+print_p2r_unknown (const unsigned char *msg, size_t msglen)
+{
+  print_p2r_header ("Unknown PC_to_RDR command", msg, msglen);
+  if (msglen < 10)
+    return;
+  print_pr_data (msg, msglen, 0);
+}
+
+
+static void
+print_r2p_header (const char *name, const unsigned char *msg, size_t msglen)
+{
+  DEBUGOUT_1 ("%s:\n", name);
+  if (msglen < 9)
+    return;
+  DEBUGOUT_1 ("  dwLength ..........: %u\n", convert_le_u32 (msg+1));
+  DEBUGOUT_1 ("  bSlot .............: %u\n", msg[5]);
+  DEBUGOUT_1 ("  bSeq ..............: %u\n", msg[6]);
+  DEBUGOUT_1 ("  bStatus ...........: %u\n", msg[7]);
+  if (msg[8])
+    DEBUGOUT_1 ("  bError ............: %u\n", msg[8]);
+}
+
+
+static void
+print_r2p_datablock (const unsigned char *msg, size_t msglen)
+{
+  print_r2p_header ("RDR_to_PC_DataBlock", msg, msglen);
+  if (msglen < 10)
+    return;
+  if (msg[9])
+    DEBUGOUT_2 ("  bChainParameter ...: 0x%02x%s\n", msg[9],
+                msg[9] == 1? " (continued)":
+                msg[9] == 2? " (continues+ends)":
+                msg[9] == 3? " (continues+continued)":
+                msg[9] == 16? " (XferBlock-expected)":"");
+  print_pr_data (msg, msglen, 10);
+}
+
+
+static void
+print_r2p_slotstatus (const unsigned char *msg, size_t msglen)
+{
+  print_r2p_header ("RDR_to_PC_SlotStatus", msg, msglen);
+  if (msglen < 10)
+    return;
+  DEBUGOUT_2 ("  bClockStatus ......: 0x%02x%s\n", msg[9],
+              msg[9] == 0? " (running)":
+              msg[9] == 1? " (stopped-L)":
+              msg[9] == 2? " (stopped-H)":
+              msg[9] == 3? " (stopped)":"");
+  print_pr_data (msg, msglen, 10);
+}
+
+
+static void
+print_r2p_parameters (const unsigned char *msg, size_t msglen)
+{
+  print_r2p_header ("RDR_to_PC_Parameters", msg, msglen);
+  if (msglen < 10)
+    return;
+
+  DEBUGOUT_1 ("  protocol ..........: T=%d\n", msg[9]);
+  if (msglen == 17 && msg[9] == 1)
+    {
+      /* Protocol T=1.  */
+      DEBUGOUT_1 ("  bmFindexDindex ....: %02X\n", msg[10]);
+      DEBUGOUT_1 ("  bmTCCKST1 .........: %02X\n", msg[11]);
+      DEBUGOUT_1 ("  bGuardTimeT1 ......: %02X\n", msg[12]);
+      DEBUGOUT_1 ("  bmWaitingIntegersT1: %02X\n", msg[13]);
+      DEBUGOUT_1 ("  bClockStop ........: %02X\n", msg[14]);
+      DEBUGOUT_1 ("  bIFSC .............: %d\n", msg[15]);
+      DEBUGOUT_1 ("  bNadValue .........: %d\n", msg[16]);
+    }
+  else
+    print_pr_data (msg, msglen, 10);
+}
+
+
+static void
+print_r2p_escape (const unsigned char *msg, size_t msglen)
+{
+  print_r2p_header ("RDR_to_PC_Escape", msg, msglen);
+  if (msglen < 10)
+    return;
+  DEBUGOUT_1 ("  buffer[9] .........: %02X\n", msg[9]);
+  print_pr_data (msg, msglen, 10);
+}
+
+
+static void
+print_r2p_datarate (const unsigned char *msg, size_t msglen)
+{
+  print_r2p_header ("RDR_to_PC_DataRate", msg, msglen);
+  if (msglen < 10)
+    return;
+  if (msglen >= 18)
+    {
+      DEBUGOUT_1 ("  dwClockFrequency ..: %u\n", convert_le_u32 (msg+10));
+      DEBUGOUT_1 ("  dwDataRate ..... ..: %u\n", convert_le_u32 (msg+14));
+      print_pr_data (msg, msglen, 18);
+    }
+  else
+    print_pr_data (msg, msglen, 10);
+}
+
+
+static void
+print_r2p_unknown (const unsigned char *msg, size_t msglen)
+{
+  print_r2p_header ("Unknown RDR_to_PC command", msg, msglen);
+  if (msglen < 10)
+    return;
+  DEBUGOUT_1 ("  bMessageType ......: %02X\n", msg[0]);
+  DEBUGOUT_1 ("  buffer[9] .........: %02X\n", msg[9]);
+  print_pr_data (msg, msglen, 10);
+}
+
+
+/* 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, unsigned short bcd_device,
+                       const unsigned char *buf, size_t buflen)
+{
+  unsigned int i;
+  unsigned int us;
+  int have_t1 = 0, have_tpdu=0;
+
+  handle->nonnull_nad = 0;
+  handle->auto_ifsd = 0;
+  handle->max_ifsd = 32;
+  handle->has_pinpad = 0;
+  handle->apdu_level = 0;
+  handle->auto_voltage = 0;
+  handle->auto_param = 0;
+  handle->auto_pps = 0;
+  DEBUGOUT_3 ("idVendor: %04X  idProduct: %04X  bcdDevice: %04X\n",
+              handle->id_vendor, handle->id_product, 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 (assumes auto voltage)\n");
+      handle->auto_voltage = 1;
+    }
+  if ((us & 0x0004))
+    DEBUGOUT ("    Auto activation on insert\n");
+  if ((us & 0x0008))
+    {
+      DEBUGOUT ("    Auto voltage selection\n");
+      handle->auto_voltage = 1;
+    }
+  if ((us & 0x0010))
+    DEBUGOUT ("    Auto clock change\n");
+  if ((us & 0x0020))
+    DEBUGOUT ("    Auto baud rate change\n");
+  if ((us & 0x0040))
+    {
+      DEBUGOUT ("    Auto parameter negotiation made by CCID\n");
+      handle->auto_param = 1;
+    }
+  else if ((us & 0x0080))
+    {
+      DEBUGOUT ("    Auto PPS made by CCID\n");
+      handle->auto_pps = 1;
+    }
+  if ((us & (0x0040 | 0x0080)) == (0x0040 | 0x0080))
+    DEBUGOUT ("    WARNING: conflicting negotiation 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 = 2;
+    }
+  else if ((us & 0x00070000))
+    DEBUGOUT ("    WARNING: conflicting exchange levels\n");
+
+  us = convert_le_u32(buf+44);
+  DEBUGOUT_1 ("  dwMaxCCIDMsgLen     %5u\n", us);
+  handle->max_ccid_msglen = 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))
+    {
+      DEBUGOUT ("this drivers requires that the reader supports T=1, "
+                "TPDU or APDU level exchange - 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
+     The
+         0x5117 - SCR 3320 USB ID-000 reader
+     seems to be very slow but enabling this workaround boosts the
+     performance to a more or less acceptable level (tested by David).
+
+  */
+  if (handle->id_vendor == VENDOR_SCM
+      && handle->max_ifsd > 48
+      && (  (handle->id_product == SCM_SCR331   && bcd_device < 0x0516)
+          ||(handle->id_product == SCM_SCR331DI && bcd_device < 0x0620)
+          ||(handle->id_product == SCM_SCR335   && bcd_device < 0x0514)
+          ||(handle->id_product == SCM_SPR532   && bcd_device < 0x0504)
+          ||(handle->id_product == SCM_SCR3320  && bcd_device < 0x0522)
+          ))
+    {
+      DEBUGOUT ("enabling workaround for buggy SCM readers\n");
+      handle->max_ifsd = 48;
+    }
+
+  if (handle->id_vendor == VENDOR_GEMPC)
+    {
+      DEBUGOUT ("enabling product quirk: disable non-null NAD\n");
+      handle->nonnull_nad = 0;
+    }
+
+  return 0;
+}
+
+
+static char *
+get_escaped_usb_string (libusb_device_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. */
+#ifdef USE_NPTH
+  npth_unprotect ();
+#endif
+  rc = libusb_control_transfer (idev, LIBUSB_ENDPOINT_IN,
+                                LIBUSB_REQUEST_GET_DESCRIPTOR,
+                                (LIBUSB_DT_STRING << 8), 0,
+                                buf, sizeof buf, 1000 /* ms timeout */);
+#ifdef USE_NPTH
+  npth_protect ();
+#endif
+  if (rc < 4)
+    langid = 0x0409; /* English.  */
+  else
+    langid = (buf[3] << 8) | buf[2];
+
+#ifdef USE_NPTH
+  npth_unprotect ();
+#endif
+  rc = libusb_control_transfer (idev, LIBUSB_ENDPOINT_IN,
+                                LIBUSB_REQUEST_GET_DESCRIPTOR,
+                                (LIBUSB_DT_STRING << 8) + idx, langid,
+                                buf, sizeof buf, 1000 /* ms timeout */);
+#ifdef USE_NPTH
+  npth_protect ();
+#endif
+  if (rc < 2 || buf[1] != LIBUSB_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 (libusb_device_handle *idev,
+                unsigned int vendor, unsigned int product,
+                unsigned char serialno_index)
+{
+  char *rid;
+  char prefix[20];
+
+  sprintf (prefix, "%04X:%04X:", (vendor & 0xffff), (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 (const struct libusb_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++)
+    {
+      const struct libusb_endpoint_descriptor *ep = ifcdesc->endpoint + no;
+      if (ep->bDescriptorType != LIBUSB_DT_ENDPOINT)
+        ;
+      else if (mode == 2
+               && ((ep->bmAttributes & LIBUSB_TRANSFER_TYPE_MASK)
+                   == LIBUSB_TRANSFER_TYPE_INTERRUPT)
+               && (ep->bEndpointAddress & 0x80))
+        return ep->bEndpointAddress;
+      else if ((mode == 0 || mode == 1)
+               && ((ep->bmAttributes & LIBUSB_TRANSFER_TYPE_MASK)
+                   == LIBUSB_TRANSFER_TYPE_BULK)
+               && (ep->bEndpointAddress & 0x80) == want_bulk_in)
+        return ep->bEndpointAddress;
+    }
+
+  return -1;
+}
+
+
+/* Helper for scan_devices. This function returns true if a
+   requested device has been found or the caller should stop scanning
+   for other reasons. */
+static void
+scan_usb_device (int *count, char **rid_list, struct libusb_device *dev)
+{
+  int ifc_no;
+  int set_no;
+  const struct libusb_interface_descriptor *ifcdesc;
+  char *rid;
+  libusb_device_handle *idev = NULL;
+  int err;
+  struct libusb_config_descriptor *config;
+  struct libusb_device_descriptor desc;
+  char *p;
+
+  err = libusb_get_device_descriptor (dev, &desc);
+  if (err)
+    return;
+
+  err = libusb_get_active_config_descriptor (dev, &config);
+  if (err)
+    return;
+
+  for (ifc_no=0; ifc_no < config->bNumInterfaces; ifc_no++)
+    for (set_no=0; set_no < config->interface[ifc_no].num_altsetting; set_no++)
+      {
+        ifcdesc = (config->interface[ifc_no].altsetting + set_no);
+        /* The second condition is for older SCM SPR 532 who did
+           not know about the assigned CCID class.  The third
+           condition does the same for a Cherry SmartTerminal
+           ST-2000.  Instead of trying to interpret the strings
+           we simply check the product ID. */
+        if (ifcdesc && ifcdesc->extra
+            && ((ifcdesc->bInterfaceClass == 11
+                 && ifcdesc->bInterfaceSubClass == 0
+                 && ifcdesc->bInterfaceProtocol == 0)
+                || (ifcdesc->bInterfaceClass == 255
+                    && desc.idVendor == VENDOR_SCM
+                    && desc.idProduct == SCM_SPR532)
+                || (ifcdesc->bInterfaceClass == 255
+                    && desc.idVendor == VENDOR_CHERRY
+                    && desc.idProduct == CHERRY_ST2000)))
+          {
+            ++*count;
+
+            err = libusb_open (dev, &idev);
+            if (err)
+              {
+                DEBUGOUT_1 ("usb_open failed: %s\n", libusb_error_name (err));
+                continue; /* with next setting. */
+              }
+
+            rid = make_reader_id (idev, desc.idVendor, desc.idProduct,
+                                  desc.iSerialNumber);
+            if (!rid)
+              {
+                libusb_free_config_descriptor (config);
+                return;
+              }
+
+            /* We are collecting infos about all available CCID
+               readers.  Store them and continue.  */
+            DEBUGOUT_2 ("found CCID reader %d (ID=%s)\n", *count, rid);
+            p = malloc ((*rid_list? strlen (*rid_list):0) + 1
+                        + strlen (rid) + 1);
+            if (p)
+              {
+                *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. */
+              {
+                libusb_free_config_descriptor (config);
+                free (rid);
+                return;
+              }
+
+            free (rid);
+            libusb_close (idev);
+            idev = NULL;
+          }
+      }
+
+  libusb_free_config_descriptor (config);
+}
+
+/* Scan all CCID devices.
+
+   The function returns 0 if a reader has been found or when a scan
+   returned without error.
+
+   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.
+*/
+static int
+scan_devices (char **r_rid)
+{
+  char *rid_list = NULL;
+  int count = 0;
+  libusb_device **dev_list = NULL;
+  libusb_device *dev;
+  int i;
+  ssize_t n;
+
+  /* Set return values to a default. */
+  if (r_rid)
+    *r_rid = NULL;
+
+  n = libusb_get_device_list (NULL, &dev_list);
+
+  for (i = 0; i < n; i++)
+    {
+      dev = dev_list[i];
+      scan_usb_device (&count, &rid_list, dev);
+    }
+
+  libusb_free_device_list (dev_list, 1);
+
+  *r_rid = rid_list;
+  return 0;
+}
+
+
+/* Set the level of debugging to LEVEL and 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, 3 additionally enables debugging for GetSlotStatus, other
+   values are not yet defined.
+
+   Note that libusb may provide its own debugging feature which is
+   enabled by setting the envvar USB_DEBUG.  */
+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)
+    {
+      int rc;
+      if ((rc = libusb_init (NULL)))
+        {
+          DEBUGOUT_1 ("usb_init failed: %s.\n", libusb_error_name (rc));
+          return NULL;
+        }
+      initialized_usb = 1;
+    }
+
+  if (scan_devices (&reader_list))
+    return NULL; /* Error. */
+  return reader_list;
+}
+
+
+/* Vendor specific custom initialization.  */
+static int
+ccid_vendor_specific_init (ccid_driver_t handle)
+{
+  int r = 0;
+
+  if (handle->id_vendor == VENDOR_VEGA && handle->id_product == VEGA_ALPHA)
+    {
+      /*
+       * Vega alpha has a feature to show retry counter on the pinpad
+       * display.  But it assumes that the card returns the value of
+       * retry counter by VERIFY with empty data (return code of
+       * 63Cx).  Unfortunately, existing OpenPGP cards don't support
+       * VERIFY command with empty data.  This vendor specific command
+       * sequence is to disable the feature.
+       */
+      const unsigned char cmd[] = { '\xb5', '\x01', '\x00', '\x03', '\x00' };
+
+      r = send_escape_cmd (handle, cmd, sizeof (cmd), NULL, 0, NULL);
+    }
+  else if (handle->id_vendor == VENDOR_SCM && handle->id_product == SCM_SPR532)
+    {
+      /*
+       * It seems that SEQ may be out of sync between host and the card reader,
+       * and SET_INTERFACE doesn't reset it.  Make sure it works at the init.
+       */
+      abort_cmd (handle, 0, 1);
+    }
+
+  if (r != 0 && r != CCID_DRIVER_ERR_CARD_INACTIVE
+      && r != CCID_DRIVER_ERR_NO_CARD)
+    return r;
+  else
+    return 0;
+}
+
+
+static int
+ccid_vendor_specific_setup (ccid_driver_t handle)
+{
+  if (handle->id_vendor == VENDOR_SCM && handle->id_product == SCM_SPR532)
+    {
+#ifdef USE_NPTH
+      npth_unprotect ();
+#endif
+      libusb_clear_halt (handle->idev, handle->ep_intr);
+#ifdef USE_NPTH
+      npth_protect ();
+#endif
+    }
+  return 0;
+}
+
+
+static int
+ccid_vendor_specific_pinpad_setup (ccid_driver_t handle)
+{
+  if (handle->id_vendor == VENDOR_SCM && handle->id_product == SCM_SPR532)
+    {
+      DEBUGOUT ("sending escape sequence to switch to a case 1 APDU\n");
+      send_escape_cmd (handle, (const unsigned char*)"\x80\x02\x00", 3,
+                       NULL, 0, NULL);
+    }
+  return 0;
+}
+
+
+gpg_error_t
+ccid_dev_scan (int *idx_max_p, void **t_p)
+{
+  ssize_t n;
+  libusb_device *dev;
+  int i;
+  int ifc_no;
+  int set_no;
+  int idx = 0;
+  int err = 0;
+
+  *idx_max_p = 0;
+  *t_p = NULL;
+
+  if (!initialized_usb)
+    {
+      int rc;
+      if ((rc = libusb_init (NULL)))
+        {
+          DEBUGOUT_1 ("usb_init failed: %s.\n", libusb_error_name (rc));
+          return gpg_error (GPG_ERR_ENODEV);
+        }
+      initialized_usb = 1;
+    }
+
+  n = libusb_get_device_list (NULL, &ccid_usb_dev_list);
+  for (i = 0; i < n; i++)
+    {
+      struct libusb_config_descriptor *config;
+      struct libusb_device_descriptor desc;
+
+      dev = ccid_usb_dev_list[i];
+
+      if (libusb_get_device_descriptor (dev, &desc))
+        continue;
+
+      if (libusb_get_active_config_descriptor (dev, &config))
+        continue;
+
+      for (ifc_no=0; ifc_no < config->bNumInterfaces; ifc_no++)
+        for (set_no=0; set_no < config->interface[ifc_no].num_altsetting;
+             set_no++)
+          {
+            const struct libusb_interface_descriptor *ifcdesc;
+
+            ifcdesc = &config->interface[ifc_no].altsetting[set_no];
+            /* The second condition is for older SCM SPR 532 who did
+               not know about the assigned CCID class.  The third
+               condition does the same for a Cherry SmartTerminal
+               ST-2000.  Instead of trying to interpret the strings
+               we simply check the product ID. */
+            if (ifcdesc && ifcdesc->extra
+                && ((ifcdesc->bInterfaceClass == 11
+                     && ifcdesc->bInterfaceSubClass == 0
+                     && ifcdesc->bInterfaceProtocol == 0)
+                    || (ifcdesc->bInterfaceClass == 255
+                        && desc.idVendor == VENDOR_SCM
+                        && desc.idProduct == SCM_SPR532)
+                    || (ifcdesc->bInterfaceClass == 255
+                        && desc.idVendor == VENDOR_CHERRY
+                        && desc.idProduct == CHERRY_ST2000)))
+              {
+                /* Found a reader.  */
+                unsigned char *ifcdesc_extra;
+
+                ifcdesc_extra = malloc (ifcdesc->extra_length);
+                if (!ifcdesc_extra)
+                  {
+                    err = gpg_error_from_syserror ();
+                    libusb_free_config_descriptor (config);
+                    goto scan_finish;
+                  }
+                memcpy (ifcdesc_extra, ifcdesc->extra, ifcdesc->extra_length);
+
+                ccid_dev_table[idx].n = i;
+                ccid_dev_table[idx].interface_number = ifc_no;
+                ccid_dev_table[idx].setting_number = set_no;
+                ccid_dev_table[idx].ifcdesc_extra = ifcdesc_extra;
+                ccid_dev_table[idx].ifcdesc_extra_len = ifcdesc->extra_length;
+                ccid_dev_table[idx].ep_bulk_out = find_endpoint (ifcdesc, 0);
+                ccid_dev_table[idx].ep_bulk_in = find_endpoint (ifcdesc, 1);
+                ccid_dev_table[idx].ep_intr = find_endpoint (ifcdesc, 2);
+
+                idx++;
+                if (idx >= CCID_MAX_DEVICE)
+                  {
+                    libusb_free_config_descriptor (config);
+                    err = 0;
+                    goto scan_finish;
+                  }
+              }
+          }
+
+      libusb_free_config_descriptor (config);
+    }
+
+ scan_finish:
+
+  if (err)
+    {
+      for (i = 0; i < idx; i++)
+        {
+          free (ccid_dev_table[i].ifcdesc_extra);
+          ccid_dev_table[i].n = 0;
+          ccid_dev_table[i].interface_number = 0;
+          ccid_dev_table[i].setting_number = 0;
+          ccid_dev_table[i].ifcdesc_extra = NULL;
+          ccid_dev_table[i].ifcdesc_extra_len = 0;
+          ccid_dev_table[i].ep_bulk_out = 0;
+          ccid_dev_table[i].ep_bulk_in = 0;
+          ccid_dev_table[i].ep_intr = 0;
+        }
+      libusb_free_device_list (ccid_usb_dev_list, 1);
+      ccid_usb_dev_list = NULL;
+    }
+  else
+    {
+      *idx_max_p = idx;
+      if (idx)
+        *t_p = ccid_dev_table;
+      else
+        *t_p = NULL;
+    }
+
+  return err;
+}
+
+void
+ccid_dev_scan_finish (void *tbl0, int max)
+{
+  int i;
+  struct ccid_dev_table *tbl = tbl0;
+
+  for (i = 0; i < max; i++)
+    {
+      free (tbl[i].ifcdesc_extra);
+      tbl[i].n = 0;
+      tbl[i].interface_number = 0;
+      tbl[i].setting_number = 0;
+      tbl[i].ifcdesc_extra = NULL;
+      tbl[i].ifcdesc_extra_len = 0;
+      tbl[i].ep_bulk_out = 0;
+      tbl[i].ep_bulk_in = 0;
+      tbl[i].ep_intr = 0;
+    }
+  libusb_free_device_list (ccid_usb_dev_list, 1);
+  ccid_usb_dev_list = NULL;
+}
+
+unsigned int
+ccid_get_BAI (int idx, void *tbl0)
+{
+  int n;
+  int bus, addr, intf;
+  unsigned int bai;
+  libusb_device *dev;
+  struct ccid_dev_table *tbl = tbl0;
+
+  n = tbl[idx].n;
+  dev = ccid_usb_dev_list[n];
+
+  bus = libusb_get_bus_number (dev);
+  addr = libusb_get_device_address (dev);
+  intf = tbl[idx].interface_number;
+  bai = (bus << 16) | (addr << 8) | intf;
+
+  return bai;
+}
+
+int
+ccid_compare_BAI (ccid_driver_t handle, unsigned int bai)
+{
+  return handle->bai == bai;
+}
+
+
+static void
+intr_cb (struct libusb_transfer *transfer)
+{
+  ccid_driver_t handle = transfer->user_data;
+
+  DEBUGOUT_2 ("CCID: interrupt callback %d (%d)\n",
+              transfer->status, transfer->actual_length);
+
+  if (transfer->status == LIBUSB_TRANSFER_TIMED_OUT)
+    {
+      int err;
+
+    submit_again:
+      /* Submit the URB again to keep watching the INTERRUPT transfer.  */
+      err = libusb_submit_transfer (transfer);
+      if (err == LIBUSB_ERROR_NO_DEVICE)
+        goto device_removed;
+
+      DEBUGOUT_1 ("CCID submit transfer again %d\n", err);
+    }
+  else if (transfer->status == LIBUSB_TRANSFER_COMPLETED)
+    {
+      size_t len = transfer->actual_length;
+      unsigned char *p = transfer->buffer;
+      int card_removed = 0;
+
+      while (len)
+        {
+          if (*p == RDR_to_PC_NotifySlotChange)
+            {
+              if (len < 2)
+                break;
+
+              DEBUGOUT_1 ("CCID: NotifySlotChange: %02x\n", p[1]);
+
+              if ((p[1] & 1))
+                card_removed = 0;
+              else
+                card_removed = 1;
+
+              p += 2;
+              len -= 2;
+            }
+          else if (*p == RDR_to_PC_HardwareError)
+            {
+              if (len < 4)
+                break;
+
+              DEBUGOUT_1 ("CCID: hardware error detected: %02x\n", p[3]);
+              p += 4;
+              len -= 4;
+            }
+          else
+            {
+              DEBUGOUT_1 ("CCID: unknown intr: %02x\n", p[0]);
+              break;
+            }
+        }
+
+      if (card_removed)
+        {
+          DEBUGOUT ("CCID: card removed\n");
+          handle->powered_off = 1;
+#if defined(GNUPG_MAJOR_VERSION)
+          scd_kick_the_loop ();
+#endif
+        }
+      else
+        {
+          /* Event other than card removal.  */
+          goto submit_again;
+        }
+    }
+  else if (transfer->status == LIBUSB_TRANSFER_CANCELLED)
+    handle->powered_off = 1;
+  else if (transfer->status == LIBUSB_TRANSFER_OVERFLOW)
+    {
+      /* Something goes wrong.  Ignore.  */
+      DEBUGOUT ("CCID: interrupt transfer overflow\n");
+    }
+  else
+    {
+    device_removed:
+      DEBUGOUT ("CCID: device removed\n");
+      handle->powered_off = 1;
+#if defined(GNUPG_MAJOR_VERSION)
+      scd_kick_the_loop ();
+#endif
+    }
+}
+
+static void
+ccid_setup_intr  (ccid_driver_t handle)
+{
+  struct libusb_transfer *transfer;
+  int err;
+
+  transfer = libusb_alloc_transfer (0);
+  handle->transfer = transfer;
+  libusb_fill_interrupt_transfer (transfer, handle->idev, handle->ep_intr,
+                                  handle->intr_buf, sizeof (handle->intr_buf),
+                                  intr_cb, handle, 0);
+  err = libusb_submit_transfer (transfer);
+  DEBUGOUT_2 ("CCID submit transfer (%x): %d", handle->ep_intr, err);
+}
+
+
+static void *
+ccid_usb_thread (void *arg)
+{
+  libusb_context *ctx = arg;
+
+  while (ccid_usb_thread_is_alive)
+    {
+#ifdef USE_NPTH
+      npth_unprotect ();
+#endif
+      libusb_handle_events_completed (ctx, NULL);
+#ifdef USE_NPTH
+      npth_protect ();
+#endif
+    }
+
+  return NULL;
+}
+
+
+static int
+ccid_open_usb_reader (const char *spec_reader_name,
+                      int idx, void *ccid_table0,
+                      ccid_driver_t *handle, char **rdrname_p)
+{
+  libusb_device *dev;
+  libusb_device_handle *idev = NULL;
+  char *rid = NULL;
+  int rc = 0;
+  int ifc_no, set_no;
+  struct libusb_device_descriptor desc;
+  int n;
+  int bus, addr;
+  unsigned int bai;
+  struct ccid_dev_table *ccid_table = ccid_table0;
+
+  n = ccid_table[idx].n;
+  ifc_no = ccid_table[idx].interface_number;
+  set_no = ccid_table[idx].setting_number;
+
+  dev = ccid_usb_dev_list[n];
+  bus = libusb_get_bus_number (dev);
+  addr = libusb_get_device_address (dev);
+  bai = (bus << 16) | (addr << 8) | ifc_no;
+
+  rc = libusb_open (dev, &idev);
+  if (rc)
+    {
+      DEBUGOUT_1 ("usb_open failed: %s\n", libusb_error_name (rc));
+      free (*handle);
+      *handle = NULL;
+      return map_libusb_error (rc);
+    }
+
+  if (ccid_usb_thread_is_alive++ == 0)
+    {
+      npth_t thread;
+      npth_attr_t tattr;
+      int err;
+
+      err = npth_attr_init (&tattr);
+      if (err)
+        {
+          DEBUGOUT_1 ("npth_attr_init failed: %s\n", strerror (err));
+          free (*handle);
+          *handle = NULL;
+          return err;
+        }
+
+      npth_attr_setdetachstate (&tattr, NPTH_CREATE_DETACHED);
+      err = npth_create (&thread, &tattr, ccid_usb_thread, NULL);
+      if (err)
+        {
+          DEBUGOUT_1 ("npth_create failed: %s\n", strerror (err));
+          free (*handle);
+          *handle = NULL;
+          return err;
+        }
+      npth_setname_np (thread, "ccid_usb_thread");
+
+      npth_attr_destroy (&tattr);
+    }
+
+  rc = libusb_get_device_descriptor (dev, &desc);
+  if (rc)
+    {
+      DEBUGOUT ("get_device_descripor failed\n");
+      rc = map_libusb_error (rc);
+      goto leave;
+    }
+
+  rid = make_reader_id (idev, desc.idVendor, desc.idProduct,
+                        desc.iSerialNumber);
+
+  /* Check to see if reader name matches the spec.  */
+  if (spec_reader_name
+      && strncmp (rid, spec_reader_name, strlen (spec_reader_name)))
+    {
+      DEBUGOUT ("device not matched\n");
+      rc = CCID_DRIVER_ERR_NO_READER;
+      goto leave;
+    }
+
+  (*handle)->id_vendor = desc.idVendor;
+  (*handle)->id_product = desc.idProduct;
+  (*handle)->idev = idev;
+  (*handle)->bai = bai;
+  (*handle)->ifc_no = ifc_no;
+  (*handle)->ep_bulk_out = ccid_table[idx].ep_bulk_out;
+  (*handle)->ep_bulk_in = ccid_table[idx].ep_bulk_in;
+  (*handle)->ep_intr = ccid_table[idx].ep_intr;
+
+  DEBUGOUT_2 ("using CCID reader %d (ID=%s)\n", idx, rid);
+
+  if (parse_ccid_descriptor (*handle, desc.bcdDevice,
+                             ccid_table[idx].ifcdesc_extra,
+                             ccid_table[idx].ifcdesc_extra_len))
+    {
+      DEBUGOUT ("device not supported\n");
+      rc = CCID_DRIVER_ERR_NO_READER;
+      goto leave;
+    }
+
+#ifdef USE_NPTH
+  npth_unprotect ();
+#endif
+  rc = libusb_claim_interface (idev, ifc_no);
+  if (rc)
+    {
+#ifdef USE_NPTH
+      npth_protect ();
+#endif
+      DEBUGOUT_1 ("usb_claim_interface failed: %d\n", rc);
+      rc = map_libusb_error (rc);
+      goto leave;
+    }
+
+  /* Submit SET_INTERFACE control transfer which can reset the device.  */
+  rc = libusb_set_interface_alt_setting (idev, ifc_no, set_no);
+  if (rc)
+    {
+#ifdef USE_NPTH
+      npth_protect ();
+#endif
+      DEBUGOUT_1 ("usb_set_interface_alt_setting failed: %d\n", rc);
+      rc = map_libusb_error (rc);
+      goto leave;
+    }
+
+#ifdef USE_NPTH
+  npth_protect ();
+#endif
+
+  rc = ccid_vendor_specific_init (*handle);
+
+ leave:
+  if (rc)
+    {
+      --ccid_usb_thread_is_alive;
+      free (rid);
+      libusb_release_interface (idev, ifc_no);
+      libusb_close (idev);
+      free (*handle);
+      *handle = NULL;
+    }
+  else
+    {
+      if (rdrname_p)
+        *rdrname_p = rid;
+      else
+        free (rid);
+    }
+
+  return rc;
+}
+
+/* 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 (const char *spec_reader_name, int idx,
+                  void *ccid_table0,
+                  ccid_driver_t *handle, char **rdrname_p)
+{
+  struct ccid_dev_table *ccid_table = ccid_table0;
+
+  *handle = calloc (1, sizeof **handle);
+  if (!*handle)
+    {
+      DEBUGOUT ("out of memory\n");
+      return CCID_DRIVER_ERR_OUT_OF_CORE;
+    }
+
+  return ccid_open_usb_reader (spec_reader_name, idx, ccid_table,
+                               handle, rdrname_p);
+}
+
+
+int
+ccid_require_get_status (ccid_driver_t handle)
+{
+  /* When a card reader supports interrupt transfer to check the
+     status of card, it is possible to submit only an interrupt
+     transfer, and no check is required by application layer.  USB can
+     detect removal of a card and can detect removal of a reader.
+  */
+  if (handle->ep_intr >= 0)
+    {
+      if (handle->id_vendor != VENDOR_SCM)
+        return 0;
+
+      /*
+       * For card reader with interrupt transfer support, ideally,
+       * removal is detected by intr_cb, but some card reader
+       * (e.g. SPR532) has a possible case of missing report to
+       * intr_cb, and another case of valid report to intr_cb.
+       *
+       * For such a reader, the removal should be able to be detected
+       * by PC_to_RDR_GetSlotStatus, too.  Thus, calls to
+       * ccid_slot_status should go on wire even if "on_wire" is not
+       * requested.
+       *
+       */
+      if (handle->transfer == NULL)
+        return 0;
+    }
+
+  /* Libusb actually detects the removal of USB device in use.
+     However, there is no good API to handle the removal (yet),
+     cleanly and with good portability.
+
+     There is libusb_set_pollfd_notifiers function, but it doesn't
+     offer libusb_device_handle* data to its callback.  So, when it
+     watches multiple devices, there is no way to know which device is
+     removed.
+
+     Once, we will have a good programming interface of libusb, we can
+     list tokens (with no interrupt transfer support, but always with
+     card inserted) here to return 0, so that scdaemon can submit
+     minimum packet on wire.
+  */
+  return 1;
+}
+
+static int
+send_power_off (ccid_driver_t handle)
+{
+  int rc;
+  unsigned char msg[100];
+  size_t msglen;
+  unsigned char seqno;
+
+  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, 0);
+  if (!rc)
+    bulk_in (handle, msg, sizeof msg, &msglen, RDR_to_PC_SlotStatus,
+             seqno, 2000, 0);
+  return rc;
+}
+
+static void
+do_close_reader (ccid_driver_t handle)
+{
+  int rc;
+
+  if (!handle->powered_off)
+    send_power_off (handle);
+
+  if (handle->transfer)
+    {
+      if (!handle->powered_off)
+        {
+          DEBUGOUT ("libusb_cancel_transfer\n");
+
+          rc = libusb_cancel_transfer (handle->transfer);
+          if (rc != LIBUSB_ERROR_NOT_FOUND)
+            while (!handle->powered_off)
+              {
+                DEBUGOUT ("libusb_handle_events_completed\n");
+#ifdef USE_NPTH
+                npth_unprotect ();
+#endif
+                libusb_handle_events_completed (NULL, &handle->powered_off);
+#ifdef USE_NPTH
+                npth_protect ();
+#endif
+              }
+        }
+
+      libusb_free_transfer (handle->transfer);
+      handle->transfer = NULL;
+    }
+
+  DEBUGOUT ("libusb_release_interface and libusb_close\n");
+  libusb_release_interface (handle->idev, handle->ifc_no);
+  --ccid_usb_thread_is_alive;
+  libusb_close (handle->idev);
+  handle->idev = NULL;
+}
+
+
+int
+ccid_set_progress_cb (ccid_driver_t handle,
+                      void (*cb)(void *, const char *, int, int, int),
+                      void *cb_arg)
+{
+  if (!handle)
+    return CCID_DRIVER_ERR_INV_VALUE;
+
+  handle->progress_cb = cb;
+  handle->progress_cb_arg = cb_arg;
+  return 0;
+}
+
+
+int
+ccid_set_prompt_cb (ccid_driver_t handle,
+		    void (*cb)(void *, int), void *cb_arg)
+{
+  if (!handle)
+    return CCID_DRIVER_ERR_INV_VALUE;
+
+  handle->prompt_cb = cb;
+  handle->prompt_cb_arg = cb_arg;
+  return 0;
+}
+
+
+/* Close the reader HANDLE. */
+int
+ccid_close_reader (ccid_driver_t handle)
+{
+  if (!handle)
+    return 0;
+
+  do_close_reader (handle);
+  free (handle);
+  return 0;
+}
+
+
+/* Return False if a card is present and powered. */
+int
+ccid_check_card_presence (ccid_driver_t handle)
+{
+  (void)handle;  /* Not yet implemented.  */
+  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 no_debug)
+{
+  int rc;
+  int transferred;
+
+  /* No need to continue and clutter the log with USB write error
+     messages after we got the first ENODEV.  */
+  if (handle->enodev_seen)
+    return CCID_DRIVER_ERR_NO_READER;
+
+  if (debug_level && (!no_debug || debug_level >= 3))
+    {
+      switch (msglen? msg[0]:0)
+        {
+        case PC_to_RDR_IccPowerOn:
+          print_p2r_iccpoweron (msg, msglen);
+          break;
+        case PC_to_RDR_IccPowerOff:
+          print_p2r_iccpoweroff (msg, msglen);
+          break;
+        case PC_to_RDR_GetSlotStatus:
+          print_p2r_getslotstatus (msg, msglen);
+          break;
+        case PC_to_RDR_XfrBlock:
+          print_p2r_xfrblock (msg, msglen);
+          break;
+        case PC_to_RDR_GetParameters:
+          print_p2r_getparameters (msg, msglen);
+          break;
+        case PC_to_RDR_ResetParameters:
+          print_p2r_resetparameters (msg, msglen);
+          break;
+        case PC_to_RDR_SetParameters:
+          print_p2r_setparameters (msg, msglen);
+          break;
+        case PC_to_RDR_Escape:
+          print_p2r_escape (msg, msglen);
+          break;
+        case PC_to_RDR_IccClock:
+          print_p2r_iccclock (msg, msglen);
+          break;
+        case PC_to_RDR_T0APDU:
+          print_p2r_to0apdu (msg, msglen);
+          break;
+        case PC_to_RDR_Secure:
+          print_p2r_secure (msg, msglen);
+          break;
+        case PC_to_RDR_Mechanical:
+          print_p2r_mechanical (msg, msglen);
+          break;
+        case PC_to_RDR_Abort:
+          print_p2r_abort (msg, msglen);
+          break;
+        case PC_to_RDR_SetDataRate:
+          print_p2r_setdatarate (msg, msglen);
+          break;
+        default:
+          print_p2r_unknown (msg, msglen);
+          break;
+        }
+    }
+
+#ifdef USE_NPTH
+  npth_unprotect ();
+#endif
+  rc = libusb_bulk_transfer (handle->idev, handle->ep_bulk_out,
+                             msg, msglen, &transferred,
+                             5000 /* ms timeout */);
+#ifdef USE_NPTH
+  npth_protect ();
+#endif
+  if (rc == 0 && transferred == msglen)
+    return 0;
+
+  if (rc)
+    {
+      DEBUGOUT_1 ("usb_bulk_write error: %s\n", libusb_error_name (rc));
+      if (rc == LIBUSB_ERROR_NO_DEVICE)
+        {
+          handle->enodev_seen = 1;
+          return CCID_DRIVER_ERR_NO_READER;
+        }
+    }
+
+  return 0;
+}
+
+
+/* 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; this can be overriden
+   with a glibal debug level of at least 3. 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 rc;
+  int msglen;
+  int notified = 0;
+  int bwi = 1;
+
+  /* Fixme: The next line for the current Valgrind without support
+     for USB IOCTLs. */
+  memset (buffer, 0, length);
+ retry:
+
+#ifdef USE_NPTH
+  npth_unprotect ();
+#endif
+  rc = libusb_bulk_transfer (handle->idev, handle->ep_bulk_in,
+                             buffer, length, &msglen, bwi*timeout);
+#ifdef USE_NPTH
+  npth_protect ();
+#endif
+  if (rc)
+    {
+      DEBUGOUT_1 ("usb_bulk_read error: %s\n", libusb_error_name (rc));
+      if (rc == LIBUSB_ERROR_NO_DEVICE)
+        handle->enodev_seen = 1;
+
+      return map_libusb_error (rc);
+    }
+  if (msglen < 0)
+    return CCID_DRIVER_ERR_INV_VALUE;  /* Faulty libusb.  */
+  *nread = msglen;
+
+  if (msglen < 10)
+    {
+      DEBUGOUT_1 ("bulk-in msg too short (%u)\n", (unsigned int)msglen);
+      abort_cmd (handle, seqno, 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]);
+      /* Retry until we are synced again.  */
+      goto retry;
+    }
+
+  /* We need to handle the time extension request before we check that
+     we got the expected message type.  This is in particular required
+     for the Cherry keyboard which sends a time extension request for
+     each key hit.  */
+  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]);
+
+      bwi = 1;
+      if (buffer[8] != 0 && buffer[8] != 0xff)
+        bwi = buffer[8];
+
+      /* Gnuk enhancement to prompt user input by ack button */
+      if (buffer[8] == 0xff && !notified)
+        {
+          notified = 1;
+	  handle->prompt_cb (handle->prompt_cb_arg, 1);
+        }
+
+      goto retry;
+    }
+
+  if (notified)
+    handle->prompt_cb (handle->prompt_cb_arg, 0);
+
+  if (buffer[0] != expected_type && buffer[0] != RDR_to_PC_SlotStatus)
+    {
+      DEBUGOUT_1 ("unexpected bulk-in msg type (%02x)\n", buffer[0]);
+      abort_cmd (handle, seqno, 0);
+      return CCID_DRIVER_ERR_INV_VALUE;
+    }
+
+  if (debug_level && (!no_debug || debug_level >= 3))
+    {
+      switch (buffer[0])
+        {
+        case RDR_to_PC_DataBlock:
+          print_r2p_datablock (buffer, msglen);
+          break;
+        case RDR_to_PC_SlotStatus:
+          print_r2p_slotstatus (buffer, msglen);
+          break;
+        case RDR_to_PC_Parameters:
+          print_r2p_parameters (buffer, msglen);
+          break;
+        case RDR_to_PC_Escape:
+          print_r2p_escape (buffer, msglen);
+          break;
+        case RDR_to_PC_DataRate:
+          print_r2p_datarate (buffer, msglen);
+          break;
+        default:
+          print_r2p_unknown (buffer, msglen);
+          break;
+        }
+    }
+  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: rc = CCID_DRIVER_ERR_CARD_INACTIVE; break;
+    case 2: rc = CCID_DRIVER_ERR_NO_CARD; break;
+    case 3: /* RFU */ break;
+    }
+
+  if (rc)
+    {
+      /*
+       * Communication failure by device side.
+       * Possibly, it was forcibly suspended and resumed.
+       */
+      if (handle->ep_intr < 0)
+        {
+          DEBUGOUT ("CCID: card inactive/removed\n");
+          handle->powered_off = 1;
+        }
+
+#if defined(GNUPG_MAJOR_VERSION)
+      scd_kick_the_loop ();
+#endif
+    }
+
+  return rc;
+}
+
+
+
+/* Send an abort sequence and wait until everything settled.  */
+static int
+abort_cmd (ccid_driver_t handle, int seqno, int init)
+{
+  int rc;
+  unsigned char dummybuf[8];
+  unsigned char msg[100];
+  int msglen;
+
+  seqno &= 0xff;
+  DEBUGOUT_1 ("sending abort sequence for seqno %d\n", seqno);
+  /* Send the abort command to the control pipe.  Note that we don't
+     need to keep track of sent abort commands because there should
+     never be another thread using the same slot concurrently.  */
+#ifdef USE_NPTH
+  npth_unprotect ();
+#endif
+  rc = libusb_control_transfer (handle->idev,
+                                0x21,/* bmRequestType: host-to-device,
+                                        class specific, to interface.  */
+                                1,   /* ABORT */
+                                (seqno << 8 | 0 /* slot */),
+                                handle->ifc_no,
+                                dummybuf, 0,
+                                1000 /* ms timeout */);
+#ifdef USE_NPTH
+  npth_protect ();
+#endif
+  if (rc)
+    {
+      DEBUGOUT_1 ("usb_control_msg error: %s\n", libusb_error_name (rc));
+      if (!init)
+        return map_libusb_error (rc);
+    }
+
+  /* Now send the abort command to the bulk out pipe using the same
+     SEQNO and SLOT.  Do this in a loop to so that all seqno are
+     tried.  */
+  seqno--;  /* Adjust for next increment.  */
+  do
+    {
+      int transferred;
+
+      seqno++;
+      msg[0] = PC_to_RDR_Abort;
+      msg[5] = 0; /* slot */
+      msg[6] = seqno;
+      msg[7] = 0; /* RFU */
+      msg[8] = 0; /* RFU */
+      msg[9] = 0; /* RFU */
+      msglen = 10;
+      set_msg_len (msg, 0);
+
+#ifdef USE_NPTH
+      npth_unprotect ();
+#endif
+      rc = libusb_bulk_transfer (handle->idev, handle->ep_bulk_out,
+                                 msg, msglen, &transferred,
+                                 init? 100: 5000 /* ms timeout */);
+#ifdef USE_NPTH
+      npth_protect ();
+#endif
+      if (rc == 0 && transferred == msglen)
+        rc = 0;
+      else if (rc)
+        DEBUGOUT_1 ("usb_bulk_write error in abort_cmd: %s\n",
+                    libusb_error_name (rc));
+
+      if (rc)
+        return map_libusb_error (rc);
+
+#ifdef USE_NPTH
+      npth_unprotect ();
+#endif
+      rc = libusb_bulk_transfer (handle->idev, handle->ep_bulk_in,
+                                 msg, sizeof msg, &msglen,
+                                 init? 100: 5000 /*ms timeout*/);
+#ifdef USE_NPTH
+      npth_protect ();
+#endif
+      if (rc)
+        {
+          DEBUGOUT_1 ("usb_bulk_read error in abort_cmd: %s\n",
+                      libusb_error_name (rc));
+          if (init && rc == LIBUSB_ERROR_TIMEOUT)
+            continue;
+          else
+            return map_libusb_error (rc);
+        }
+
+      if (msglen < 10)
+        {
+          DEBUGOUT_1 ("bulk-in msg in abort_cmd too short (%u)\n",
+                      (unsigned int)msglen);
+          return CCID_DRIVER_ERR_INV_VALUE;
+        }
+      if (msg[5] != 0)
+        {
+          DEBUGOUT_1 ("unexpected bulk-in slot (%d) in abort_cmd\n", msg[5]);
+          return CCID_DRIVER_ERR_INV_VALUE;
+        }
+
+      DEBUGOUT_3 ("status: %02X  error: %02X  octet[9]: %02X\n",
+                  msg[7], msg[8], msg[9]);
+      if (CCID_COMMAND_FAILED (msg))
+        print_command_failed (msg);
+    }
+  while (rc == LIBUSB_ERROR_TIMEOUT
+         || (msg[0] != RDR_to_PC_SlotStatus && msg[5] != 0 && msg[6] != seqno));
+
+  handle->seqno = ((seqno + 1) & 0xff);
+  DEBUGOUT ("sending abort sequence succeeded\n");
+
+  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 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);
+
+  rc = bulk_out (handle, msg, msglen, 0);
+  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);
+              if (resultlen)
+                *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];
+  int msglen;
+  int i, j;
+
+  rc = libusb_interrupt_transfer (handle->idev, handle->ep_intr,
+                                  msg, sizeof msg, &msglen,
+                                  0 /* ms timeout */ );
+  if (rc == LIBUSB_ERROR_TIMEOUT)
+    return 0;
+
+  if (rc)
+    {
+      DEBUGOUT_1 ("usb_intr_read error: %s\n", libusb_error_name (rc));
+      return CCID_DRIVER_ERR_CARD_IO_ERROR;
+    }
+
+  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 occurred\n");
+    }
+  else
+    {
+      DEBUGOUT_1 ("unknown intr-in msg of type %02X\n", msg[0]);
+    }
+
+  return 0;
+}
+
+
+/* Note that this function won't return the error codes NO_CARD or
+   CARD_INACTIVE */
+int
+ccid_slot_status (ccid_driver_t handle, int *statusbits, int on_wire)
+{
+  int rc;
+  unsigned char msg[100];
+  size_t msglen;
+  unsigned char seqno;
+  int retries = 0;
+
+  if (handle->powered_off)
+    return CCID_DRIVER_ERR_NO_READER;
+
+  /* If the card (with its lower-level driver) doesn't require
+     GET_STATUS on wire (because it supports INTERRUPT transfer for
+     status change, or it's a token which has a card always inserted),
+     no need to send on wire.  */
+  if (!on_wire && !ccid_require_get_status (handle))
+    {
+      /* Setup interrupt transfer at the initial call of slot_status
+         with ON_WIRE == 0 */
+      if (handle->transfer == NULL)
+        ccid_setup_intr (handle);
+
+      *statusbits = 0;
+      return 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, 1);
+  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 || rc == CCID_DRIVER_ERR_USB_TIMEOUT)
+      && retries < 3)
+    {
+      if (!retries)
+        {
+          DEBUGOUT ("USB: CALLING USB_CLEAR_HALT\n");
+#ifdef USE_NPTH
+          npth_unprotect ();
+#endif
+          libusb_clear_halt (handle->idev, handle->ep_bulk_in);
+          libusb_clear_halt (handle->idev, handle->ep_bulk_out);
+#ifdef USE_NPTH
+          npth_protect ();
+#endif
+        }
+      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;
+}
+
+
+/* Parse ATR string (of ATRLEN) and update parameters at PARAM.
+   Calling this routine, it should prepare default values at PARAM
+   beforehand.  This routine assumes that card is accessed by T=1
+   protocol.  It doesn't analyze historical bytes at all.
+
+   Returns < 0 value on error:
+     -1 for parse error or integrity check error
+     -2 for card doesn't support T=1 protocol
+     -3 for parameters are nod explicitly defined by ATR
+     -4 for this driver doesn't support CRC
+
+   Returns >= 0 on success:
+      0 for card is negotiable mode
+      1 for card is specific mode (and not negotiable)
+ */
+static int
+update_param_by_atr (unsigned char *param, unsigned char *atr, size_t atrlen)
+{
+  int i = -1;
+  int t, y, chk;
+  int historical_bytes_num, negotiable = 1;
+
+#define NEXTBYTE() do { i++; if (atrlen <= i) return -1; } while (0)
+
+  NEXTBYTE ();
+
+  if (atr[i] == 0x3F)
+    param[1] |= 0x02;           /* Convention is inverse.  */
+  NEXTBYTE ();
+
+  y = (atr[i] >> 4);
+  historical_bytes_num = atr[i] & 0x0f;
+  NEXTBYTE ();
+
+  if ((y & 1))
+    {
+      param[0] = atr[i];        /* TA1 - Fi & Di */
+      NEXTBYTE ();
+    }
+
+  if ((y & 2))
+    NEXTBYTE ();                /* TB1 - ignore */
+
+  if ((y & 4))
+    {
+      param[2] = atr[i];        /* TC1 - Guard Time */
+      NEXTBYTE ();
+    }
+
+  if ((y & 8))
+    {
+      y = (atr[i] >> 4);        /* TD1 */
+      t = atr[i] & 0x0f;
+      NEXTBYTE ();
+
+      if ((y & 1))
+        {                       /* TA2 - PPS mode */
+          if ((atr[i] & 0x0f) != 1)
+            return -2;          /* Wrong card protocol (!= 1).  */
+
+          if ((atr[i] & 0x10) != 0x10)
+            return -3; /* Transmission parameters are implicitly defined. */
+
+          negotiable = 0;       /* TA2 means specific mode.  */
+          NEXTBYTE ();
+        }
+
+      if ((y & 2))
+        NEXTBYTE ();            /* TB2 - ignore */
+
+      if ((y & 4))
+        NEXTBYTE ();            /* TC2 - ignore */
+
+      if ((y & 8))
+        {
+          y = (atr[i] >> 4);    /* TD2 */
+          t = atr[i] & 0x0f;
+          NEXTBYTE ();
+        }
+      else
+        y = 0;
+
+      while (y)
+        {
+          if ((y & 1))
+            {                   /* TAx */
+              if (t == 1)
+                param[5] = atr[i]; /* IFSC */
+              else if (t == 15)
+                /* XXX: check voltage? */
+                param[4] = (atr[i] >> 6); /* ClockStop */
+
+              NEXTBYTE ();
+            }
+
+          if ((y & 2))
+            {
+              if (t == 1)
+                param[3] = atr[i]; /* TBx - BWI & CWI */
+              NEXTBYTE ();
+            }
+
+          if ((y & 4))
+            {
+              if (t == 1)
+                param[1] |= (atr[i] & 0x01); /* TCx - LRC/CRC */
+              NEXTBYTE ();
+
+              if (param[1] & 0x01)
+                return -4;      /* CRC not supported yet.  */
+            }
+
+          if ((y & 8))
+            {
+              y = (atr[i] >> 4); /* TDx */
+              t = atr[i] & 0x0f;
+              NEXTBYTE ();
+            }
+          else
+            y = 0;
+        }
+    }
+
+  i += historical_bytes_num - 1;
+  NEXTBYTE ();
+  if (atrlen != i+1)
+    return -1;
+
+#undef NEXTBYTE
+
+  chk = 0;
+  do
+    {
+      chk ^= atr[i];
+      i--;
+    }
+  while (i > 0);
+
+  if (chk != 0)
+    return -1;
+
+  return negotiable;
+}
+
+
+/* Return the ATR of the card.  This is not a cached value and thus an
+   actual reset is done.  */
+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 tried_iso = 0;
+  int got_param;
+  unsigned char param[7] = { /* For Protocol T=1 */
+    0x11, /* bmFindexDindex */
+    0x10, /* bmTCCKST1 */
+    0x00, /* bGuardTimeT1 */
+    0x4d, /* bmWaitingIntegersT1 */
+    0x00, /* bClockStop */
+    0x20, /* bIFSC */
+    0x00  /* bNadValue */
+  };
+
+  /* First check whether a card is available.  */
+  rc = ccid_slot_status (handle, &statusbits, 1);
+  if (rc)
+    return rc;
+  if (statusbits == 2)
+    return CCID_DRIVER_ERR_NO_CARD;
+
+  /*
+   * In the first invocation of ccid_slot_status, card reader may
+   * return CCID_DRIVER_ERR_CARD_INACTIVE and handle->powered_off may
+   * become 1.  Because inactive card is no problem (we are turning it
+   * ON here), clear the flag.
+   */
+  handle->powered_off = 0;
+
+  /* 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++;
+  /* power select (0=auto, 1=5V, 2=3V, 3=1.8V) */
+  msg[7] = handle->auto_voltage ? 0 : 1;
+  msg[8] = 0; /* RFU */
+  msg[9] = 0; /* RFU */
+  set_msg_len (msg, 0);
+  msglen = 10;
+
+  rc = bulk_out (handle, msg, msglen, 0);
+  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 (statusbits == 0 && CCID_COMMAND_FAILED (msg))
+    {
+      /* Card was active already, and something went wrong with
+         PC_to_RDR_IccPowerOn command.  It may be baud-rate mismatch
+         between the card and the reader.  To recover from this state,
+         send PC_to_RDR_IccPowerOff command to reset the card and try
+         again.
+       */
+      rc = send_power_off (handle);
+      if (rc)
+        return rc;
+
+      statusbits = 1;
+      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;
+    }
+
+  param[6] = handle->nonnull_nad? ((1 << 4) | 0): 0;
+  rc = update_param_by_atr (param, msg+10, msglen - 10);
+  if (rc < 0)
+    {
+      DEBUGOUT_1 ("update_param_by_atr failed: %d\n", rc);
+      return CCID_DRIVER_ERR_CARD_IO_ERROR;
+    }
+
+  got_param = 0;
+
+  if (handle->auto_param)
+    {
+      msg[0] = PC_to_RDR_GetParameters;
+      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, 0);
+      if (!rc)
+        rc = bulk_in (handle, msg, sizeof msg, &msglen, RDR_to_PC_Parameters,
+                      seqno, 2000, 0);
+      if (rc)
+        DEBUGOUT ("GetParameters failed\n");
+      else if (msglen == 17 && msg[9] == 1)
+        got_param = 1;
+    }
+  else if (handle->auto_pps)
+    ;
+  else if (rc == 1)             /* It's negotiable, send PPS.  */
+    {
+      msg[0] = PC_to_RDR_XfrBlock;
+      msg[5] = 0; /* slot */
+      msg[6] = seqno = handle->seqno++;
+      msg[7] = 0;
+      msg[8] = 0;
+      msg[9] = 0;
+      msg[10] = 0xff;           /* PPSS */
+      msg[11] = 0x11;           /* PPS0: PPS1, Protocol T=1 */
+      msg[12] = param[0];       /* PPS1: Fi / Di */
+      msg[13] = 0xff ^ 0x11 ^ param[0]; /* PCK */
+      set_msg_len (msg, 4);
+      msglen = 10 + 4;
+
+      rc = bulk_out (handle, msg, msglen, 0);
+      if (rc)
+        return rc;
+
+      rc = bulk_in (handle, msg, sizeof msg, &msglen, RDR_to_PC_DataBlock,
+                    seqno, 5000, 0);
+      if (rc)
+        return rc;
+
+      if (msglen != 10 + 4)
+        {
+          DEBUGOUT_1 ("Setting PPS failed: %zu\n", msglen);
+          return CCID_DRIVER_ERR_CARD_IO_ERROR;
+        }
+
+      if (msg[10] != 0xff || msg[11] != 0x11 || msg[12] != param[0])
+        {
+          DEBUGOUT_1 ("Setting PPS failed: 0x%02x\n", param[0]);
+          return CCID_DRIVER_ERR_CARD_IO_ERROR;
+        }
+    }
+
+  /* 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 */
+
+  if (!got_param)
+    memcpy (&msg[10], param, 7);
+  set_msg_len (msg, 7);
+  msglen = 10 + 7;
+
+  rc = bulk_out (handle, msg, msglen, 0);
+  if (rc)
+    return rc;
+  rc = bulk_in (handle, msg, sizeof msg, &msglen, RDR_to_PC_Parameters,
+                seqno, 5000, 0);
+  if (rc)
+    DEBUGOUT ("SetParameters failed (ignored)\n");
+
+  if (!rc && msglen > 15 && msg[15] >= 16 && msg[15] <= 254 )
+    handle->ifsc = msg[15];
+  else
+    handle->ifsc = 128; /* Something went wrong, assume 128 bytes.  */
+
+  if (handle->nonnull_nad && msglen > 16 && msg[16] == 0)
+    {
+      DEBUGOUT ("Use Null-NAD, clearing handle->nonnull_nad.\n");
+      handle->nonnull_nad = 0;
+    }
+
+  handle->t1_ns = 0;
+  handle->t1_nr = 0;
+
+  /* Send an S-Block with our maximum IFSD to the CCID.  */
+  if (!handle->apdu_level && !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;
+
+      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, 0);
+      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]);
+    }
+
+  ccid_vendor_specific_setup (handle);
+  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;
+    }
+}
+
+
+/* Return true if APDU is an extended length one.  */
+static int
+is_exlen_apdu (const unsigned char *apdu, size_t apdulen)
+{
+  if (apdulen < 7 || apdu[4])
+    return 0;  /* Too short or no Z byte.  */
+  return 1;
+}
+
+
+/* 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_len,
+                            unsigned char *resp, size_t maxresplen,
+                            size_t *nresp)
+{
+  int rc;
+  unsigned char msg[CCID_MAX_BUF];
+  const unsigned char *apdu_p;
+  size_t apdu_part_len;
+  size_t msglen;
+  unsigned char seqno;
+  int bwi = 0;
+  unsigned char chain = 0;
+
+  if (apdu_len == 0 || apdu_len > sizeof (msg) - 10)
+    return CCID_DRIVER_ERR_INV_VALUE; /* Invalid length. */
+
+  apdu_p = apdu_buf;
+  while (1)
+    {
+      apdu_part_len = apdu_len;
+      if (apdu_part_len > handle->max_ccid_msglen - 10)
+        {
+          apdu_part_len = handle->max_ccid_msglen - 10;
+          chain |= 0x01;
+        }
+
+      msg[0] = PC_to_RDR_XfrBlock;
+      msg[5] = 0; /* slot */
+      msg[6] = seqno = handle->seqno++;
+      msg[7] = bwi;
+      msg[8] = chain;
+      msg[9] = 0;
+      memcpy (msg+10, apdu_p, apdu_part_len);
+      set_msg_len (msg, apdu_part_len);
+      msglen = 10 + apdu_part_len;
+
+      rc = bulk_out (handle, msg, msglen, 0);
+      if (rc)
+        return rc;
+
+      apdu_p += apdu_part_len;
+      apdu_len -= apdu_part_len;
+
+      rc = bulk_in (handle, msg, sizeof msg, &msglen,
+                    RDR_to_PC_DataBlock, seqno, CCID_CMD_TIMEOUT, 0);
+      if (rc)
+        return rc;
+
+      if (!(chain & 0x01))
+        break;
+
+      chain = 0x02;
+    }
+
+  apdu_len = 0;
+  while (1)
+    {
+      apdu_part_len = msglen - 10;
+      if (resp && apdu_len + apdu_part_len <= maxresplen)
+        memcpy (resp + apdu_len, msg+10, apdu_part_len);
+      apdu_len += apdu_part_len;
+
+      if (!(msg[9] & 0x01))
+        break;
+
+      msg[0] = PC_to_RDR_XfrBlock;
+      msg[5] = 0; /* slot */
+      msg[6] = seqno = handle->seqno++;
+      msg[7] = bwi;
+      msg[8] = 0x10;                /* Request next data block */
+      msg[9] = 0;
+      set_msg_len (msg, 0);
+      msglen = 10;
+
+      rc = bulk_out (handle, msg, msglen, 0);
+      if (rc)
+        return rc;
+
+      rc = bulk_in (handle, msg, sizeof msg, &msglen,
+                    RDR_to_PC_DataBlock, seqno, CCID_CMD_TIMEOUT, 0);
+      if (rc)
+        return rc;
+    }
+
+  if (resp)
+    {
+      if (apdu_len > maxresplen)
+        {
+          DEBUGOUT_2 ("provided buffer too short for received data "
+                      "(%u/%u)\n",
+                      (unsigned int)apdu_len, (unsigned int)maxresplen);
+          return CCID_DRIVER_ERR_INV_VALUE;
+        }
+
+      *nresp = apdu_len;
+    }
+
+  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 = resynchronization 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;
+  /* The size of the buffer used to be 10+259.  For the via_escape
+     hack we need one extra byte, thus 11+259.  */
+  unsigned char send_buffer[11+259], recv_buffer[11+259];
+  const unsigned char *apdu;
+  size_t apdulen;
+  unsigned char *msg, *tpdu, *p;
+  size_t msglen, tpdulen, last_tpdulen, n;
+  unsigned char seqno;
+  unsigned int edc;
+  int use_crc = 0;
+  int hdrlen, pcboff;
+  size_t dummy_nresp;
+  int via_escape = 0;
+  int next_chunk = 1;
+  int sending = 1;
+  int retries = 0;
+  int resyncing = 0;
+  int nad_byte;
+  int wait_more = 0;
+
+  if (!nresp)
+    nresp = &dummy_nresp;
+  *nresp = 0;
+
+  /* Smarter readers allow sending APDUs directly; divert here. */
+  if (handle->apdu_level)
+    {
+      /* We employ a hack for Omnikey readers which are able to send
+         TPDUs using an escape sequence.  There is no documentation
+         but the Windows driver does it this way.  Tested using a
+         CM6121.  This method works also for the Cherry XX44
+         keyboards; however there are problems with the
+         ccid_transceive_secure which leads to a loss of sync on the
+         CCID level.  If Cherry wants to make their keyboard work
+         again, they should hand over some docs. */
+      if ((handle->id_vendor == VENDOR_OMNIKEY)
+          && handle->apdu_level < 2
+          && is_exlen_apdu (apdu_buf, apdu_buflen))
+        via_escape = 1;
+      else
+        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;
+  hdrlen = via_escape? 11 : 10;
+
+  /* NAD: DAD=1, SAD=0 */
+  nad_byte = handle->nonnull_nad? ((1 << 4) | 0): 0;
+  if (via_escape)
+    nad_byte = 0;
+
+  last_tpdulen = 0;  /* Avoid gcc warning (controlled by RESYNCING). */
+  for (;;)
+    {
+      if (next_chunk)
+        {
+          next_chunk = 0;
+
+          apdu = apdu_buf;
+          apdulen = apdu_buflen;
+          assert (apdulen);
+
+          /* Construct an I-Block. */
+          tpdu = msg + hdrlen;
+          tpdu[0] = nad_byte;
+          tpdu[1] = ((handle->t1_ns & 1) << 6); /* I-block */
+          if (apdulen > handle->ifsc )
+            {
+              apdulen = handle->ifsc;
+              apdu_buf += handle->ifsc;
+              apdu_buflen -= handle->ifsc;
+              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;
+        }
+
+      if (via_escape)
+        {
+          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 */
+          msg[10] = 0x1a; /* Omnikey command to send a TPDU.  */
+          set_msg_len (msg, 1 + tpdulen);
+        }
+      else
+        {
+          msg[0] = PC_to_RDR_XfrBlock;
+          msg[5] = 0; /* slot */
+          msg[6] = seqno = handle->seqno++;
+          msg[7] = (wait_more ? wait_more : 1); /* bBWI */
+          msg[8] = 0; /* RFU */
+          msg[9] = 0; /* RFU */
+          set_msg_len (msg, tpdulen);
+        }
+      msglen = hdrlen + tpdulen;
+      if (!resyncing)
+        last_tpdulen = tpdulen;
+      pcboff = hdrlen+1;
+
+      if (debug_level > 1)
+        DEBUGOUT_3 ("T=1: put %c-block seq=%d%s\n",
+                    ((msg[pcboff] & 0xc0) == 0x80)? 'R' :
+                    (msg[pcboff] & 0x80)? 'S' : 'I',
+                    ((msg[pcboff] & 0x80)? !!(msg[pcboff]& 0x10)
+                     : !!(msg[pcboff] & 0x40)),
+                    (!(msg[pcboff] & 0x80) && (msg[pcboff] & 0x20)?
+                     " [more]":""));
+
+      rc = bulk_out (handle, msg, msglen, 0);
+      if (rc)
+        return rc;
+
+      msg = recv_buffer;
+      rc = bulk_in (handle, msg, sizeof recv_buffer, &msglen,
+                    via_escape? RDR_to_PC_Escape : RDR_to_PC_DataBlock, seqno,
+                    (wait_more ? wait_more : 1) * CCID_CMD_TIMEOUT, 0);
+      if (rc)
+        return rc;
+
+      tpdu = msg + hdrlen;
+      tpdulen = msglen - hdrlen;
+      resyncing = 0;
+
+      if (tpdulen < 4)
+        {
+#ifdef USE_NPTH
+          npth_unprotect ();
+#endif
+          libusb_clear_halt (handle->idev, handle->ep_bulk_in);
+#ifdef USE_NPTH
+          npth_protect ();
+#endif
+          return CCID_DRIVER_ERR_ABORTED;
+        }
+
+      if (debug_level > 1)
+        DEBUGOUT_4 ("T=1: got %c-block seq=%d err=%d%s\n",
+                    ((msg[pcboff] & 0xc0) == 0x80)? 'R' :
+                              (msg[pcboff] & 0x80)? 'S' : 'I',
+                    ((msg[pcboff] & 0x80)? !!(msg[pcboff]& 0x10)
+                     : !!(msg[pcboff] & 0x40)),
+                    ((msg[pcboff] & 0xc0) == 0x80)? (msg[pcboff] & 0x0f) : 0,
+                    (!(msg[pcboff] & 0x80) && (msg[pcboff] & 0x20)?
+                     " [more]":""));
+
+      wait_more = 0;
+      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)
+            { /* Response does not match our sequence number. */
+              msg = send_buffer;
+              tpdu = msg + hdrlen;
+              tpdu[0] = nad_byte;
+              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 + hdrlen;
+          tpdu[0] = nad_byte;
+          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))
+            {
+              retries++;
+              if (via_escape && retries == 1 && (msg[pcboff] & 0x0f))
+                {
+                  /* Error probably due to switching to TPDU.  Send a
+                     resync request.  We use the recv_buffer so that
+                     we don't corrupt the send_buffer.  */
+                  msg = recv_buffer;
+                  tpdu = msg + hdrlen;
+                  tpdu[0] = nad_byte;
+                  tpdu[1] = 0xc0; /* S-block resync request. */
+                  tpdu[2] = 0;
+                  tpdulen = 3;
+                  edc = compute_edc (tpdu, tpdulen, use_crc);
+                  if (use_crc)
+                    tpdu[tpdulen++] = (edc >> 8);
+                  tpdu[tpdulen++] = edc;
+                  resyncing = 1;
+                  DEBUGOUT ("T=1: requesting resync\n");
+                }
+              else if (retries > 3)
+                {
+                  DEBUGOUT ("T=1: 3 failed retries\n");
+                  return CCID_DRIVER_ERR_CARD_IO_ERROR;
+                }
+              else
+                {
+                  /* Error: repeat last block */
+                  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) == 1 && tpdu[2] == 1)
+            {
+              /* Information field size request.  */
+              unsigned char ifsc = tpdu[3];
+
+              if (ifsc < 16 || ifsc > 254)
+                return CCID_DRIVER_ERR_CARD_IO_ERROR;
+
+              msg = send_buffer;
+              tpdu = msg + hdrlen;
+              tpdu[0] = nad_byte;
+              tpdu[1] = (0xc0 | 0x20 | 1); /* S-block response */
+              tpdu[2] = 1;
+              tpdu[3] = ifsc;
+              tpdulen = 4;
+              edc = compute_edc (tpdu, tpdulen, use_crc);
+              if (use_crc)
+                tpdu[tpdulen++] = (edc >> 8);
+              tpdu[tpdulen++] = edc;
+              DEBUGOUT_1 ("T=1: requesting an ifsc=%d\n", ifsc);
+            }
+          else if ( !(tpdu[1] & 0x20) && (tpdu[1] & 0x1f) == 3 && tpdu[2])
+            {
+              /* Wait time extension request. */
+              unsigned char bwi = tpdu[3];
+
+	      wait_more = bwi;
+
+              msg = send_buffer;
+              tpdu = msg + hdrlen;
+              tpdu[0] = nad_byte;
+              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);
+              print_progress (handle);
+            }
+          else if ( (tpdu[1] & 0x20) && (tpdu[1] & 0x1f) == 0 && !tpdu[2])
+            {
+              DEBUGOUT ("T=1: resync ack from reader\n");
+              /* Repeat previous block.  */
+              msg = send_buffer;
+              tpdulen = last_tpdulen;
+            }
+          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.
+
+   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,
+                        pininfo_t *pininfo,
+                        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;
+  size_t dummy_nresp;
+  int testmode;
+  int cherry_mode = 0;
+  int add_zero = 0;
+  int enable_varlen = 0;
+
+  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))
+    ;
+  else
+    return CCID_DRIVER_ERR_NO_PINPAD;
+
+  if (!pininfo->minlen)
+    pininfo->minlen = 1;
+  if (!pininfo->maxlen)
+    pininfo->maxlen = 15;
+
+  /* Note that the 25 is the maximum value the SPR532 allows.  */
+  if (pininfo->minlen < 1 || pininfo->minlen > 25
+      || pininfo->maxlen < 1 || pininfo->maxlen > 25
+      || pininfo->minlen > pininfo->maxlen)
+    return CCID_DRIVER_ERR_INV_VALUE;
+
+  /* We have only tested a few readers so better don't risk anything
+     and do not allow the use with other readers. */
+  switch (handle->id_vendor)
+    {
+    case VENDOR_SCM:  /* Tested with SPR 532. */
+    case VENDOR_KAAN: /* Tested with KAAN Advanced (1.02). */
+    case VENDOR_FSIJ: /* Tested with Gnuk (0.21). */
+      pininfo->maxlen = 25;
+      enable_varlen = 1;
+      break;
+    case VENDOR_REINER:/* Tested with cyberJack go */
+    case VENDOR_VASCO: /* Tested with DIGIPASS 920 */
+      enable_varlen = 1;
+      break;
+    case VENDOR_CHERRY:
+      pininfo->maxlen = 15;
+      enable_varlen = 1;
+      /* The CHERRY XX44 keyboard echos an asterisk for each entered
+         character on the keyboard channel.  We use a special variant
+         of PC_to_RDR_Secure which directs these characters to the
+         smart card's bulk-in channel.  We also need to append a zero
+         Lc byte to the APDU.  It seems that it will be replaced with
+         the actual length instead of being appended before the APDU
+         is send to the card. */
+      add_zero = 1;
+      if (handle->id_product != CHERRY_ST2000)
+        cherry_mode = 1;
+      break;
+    case VENDOR_NXP:
+      if (handle->id_product == CRYPTOUCAN){
+        pininfo->maxlen = 25;
+        enable_varlen = 1;
+        break;
+      }
+      return CCID_DRIVER_ERR_NOT_SUPPORTED;
+    case VENDOR_GEMPC:
+      if (handle->id_product == GEMPC_PINPAD)
+        {
+          enable_varlen = 0;
+          pininfo->minlen = 4;
+          pininfo->maxlen = 8;
+          break;
+        }
+      else if (handle->id_product == GEMPC_EZIO)
+        {
+          pininfo->maxlen = 25;
+          enable_varlen = 1;
+          break;
+        }
+      return CCID_DRIVER_ERR_NOT_SUPPORTED;
+    default:
+      if ((handle->id_vendor == VENDOR_VEGA &&
+           handle->id_product == VEGA_ALPHA))
+        {
+          enable_varlen = 0;
+          pininfo->minlen = 4;
+          pininfo->maxlen = 8;
+          break;
+        }
+     return CCID_DRIVER_ERR_NOT_SUPPORTED;
+    }
+
+  if (enable_varlen)
+    pininfo->fixedlen = 0;
+
+  if (testmode)
+    return 0; /* Success */
+
+  if (pininfo->fixedlen < 0 || pininfo->fixedlen >= 16)
+    return CCID_DRIVER_ERR_NOT_SUPPORTED;
+
+  ccid_vendor_specific_pinpad_setup (handle);
+
+  msg = send_buffer;
+  msg[0] = cherry_mode? 0x89 : PC_to_RDR_Secure;
+  msg[5] = 0; /* slot */
+  msg[6] = seqno = handle->seqno++;
+  msg[7] = 0; /* bBWI */
+  msg[8] = 0; /* RFU */
+  msg[9] = 0; /* RFU */
+  msg[10] = apdu_buf[1] == 0x20 ? 0 : 1;
+               /* Perform PIN verification or PIN modification. */
+  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 products.  Kudos to Martin Paljak for this
+         hint.  */
+      msg[13] = msg[14] = 0;
+    }
+  else
+    {
+      msg[13] = pininfo->fixedlen; /* bmPINBlockString:
+                                      0 bits of pin length to insert.
+                                      PIN block size by fixedlen.  */
+      msg[14] = 0x00; /* bmPINLengthFormat:
+                         Units are bytes, position is 0. */
+    }
+
+  msglen = 15;
+  if (apdu_buf[1] == 0x24)
+    {
+      msg[msglen++] = 0;    /* bInsertionOffsetOld */
+      msg[msglen++] = pininfo->fixedlen;    /* bInsertionOffsetNew */
+    }
+
+  /* The following is a little endian word. */
+  msg[msglen++] = pininfo->maxlen;   /* wPINMaxExtraDigit-Maximum.  */
+  msg[msglen++] = pininfo->minlen;   /* wPINMaxExtraDigit-Minimum.  */
+
+  if (apdu_buf[1] == 0x24)
+    msg[msglen++] = apdu_buf[2] == 0 ? 0x03 : 0x01;
+              /* bConfirmPIN
+               *    0x00: new PIN once
+               *    0x01: new PIN twice (confirmation)
+               *    0x02: old PIN and new PIN once
+               *    0x03: old PIN and new PIN twice (confirmation)
+               */
+
+  msg[msglen] = 0x02; /* bEntryValidationCondition:
+                         Validation key pressed */
+  if (pininfo->minlen && pininfo->maxlen && pininfo->minlen == pininfo->maxlen)
+    msg[msglen] |= 0x01; /* Max size reached.  */
+  msglen++;
+
+  if (apdu_buf[1] == 0x20)
+    msg[msglen++] = 0x01; /* bNumberMessage. */
+  else
+    msg[msglen++] = 0x03; /* bNumberMessage. */
+
+  msg[msglen++] = 0x09; /* wLangId-Low:  English FIXME: use the first entry. */
+  msg[msglen++] = 0x04; /* wLangId-High. */
+
+  if (apdu_buf[1] == 0x20)
+    msg[msglen++] = 0;    /* bMsgIndex. */
+  else
+    {
+      msg[msglen++] = 0;    /* bMsgIndex1. */
+      msg[msglen++] = 1;    /* bMsgIndex2. */
+      msg[msglen++] = 2;    /* bMsgIndex3. */
+    }
+
+  /* Calculate Lc.  */
+  n = pininfo->fixedlen;
+  if (apdu_buf[1] == 0x24)
+    n += pininfo->fixedlen;
+
+  /* bTeoProlog follows: */
+  msg[msglen++] = handle->nonnull_nad? ((1 << 4) | 0): 0;
+  msg[msglen++] = ((handle->t1_ns & 1) << 6); /* I-block */
+  if (n)
+    msg[msglen++] = n + 5; /* apdulen should be filled for fixed length.  */
+  else
+    msg[msglen++] = 0; /* The apdulen will be filled in by the reader.  */
+  /* APDU follows:  */
+  msg[msglen++] = apdu_buf[0]; /* CLA */
+  msg[msglen++] = apdu_buf[1]; /* INS */
+  msg[msglen++] = apdu_buf[2]; /* P1 */
+  msg[msglen++] = apdu_buf[3]; /* P2 */
+  if (add_zero)
+    msg[msglen++] = 0;
+  else if (pininfo->fixedlen != 0)
+    {
+      msg[msglen++] = n;
+      memset (&msg[msglen], 0xff, n);
+      msglen += n;
+    }
+  /* An EDC is not required. */
+  set_msg_len (msg, msglen - 10);
+
+  rc = bulk_out (handle, msg, msglen, 0);
+  if (rc)
+    return rc;
+
+  msg = recv_buffer;
+  rc = bulk_in (handle, msg, sizeof recv_buffer, &msglen,
+                RDR_to_PC_DataBlock, seqno, 30000, 0);
+  if (rc)
+    return rc;
+
+  tpdu = msg + 10;
+  tpdulen = msglen - 10;
+
+  if (handle->apdu_level)
+    {
+      if (resp)
+        {
+          if (tpdulen > maxresplen)
+            {
+              DEBUGOUT_2 ("provided buffer too short for received data "
+                          "(%u/%u)\n",
+                          (unsigned int)tpdulen, (unsigned int)maxresplen);
+              return CCID_DRIVER_ERR_INV_VALUE;
+            }
+
+          memcpy (resp, tpdu, tpdulen);
+          *nresp = tpdulen;
+        }
+      return 0;
+    }
+
+  if (tpdulen < 4)
+    {
+#ifdef USE_NPTH
+      npth_unprotect ();
+#endif
+      libusb_clear_halt (handle->idev, handle->ep_bulk_in);
+#ifdef USE_NPTH
+      npth_protect ();
+#endif
+      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)
+        { /* Response 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);
+          *nresp += 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)
+        { /* 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
+        { /* 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"; break;
+    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)
+{
+  gpg_error_t err;
+  ccid_driver_t ccid;
+  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;
+  int idx_max;
+  struct ccid_dev_table *ccid_table;
+
+  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 (ccid_set_debug_level (-1)+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;
+    }
+
+  err = ccid_dev_scan (&idx_max, &ccid_table);
+  if (err)
+    return 1;
+
+  if (idx_max == 0)
+    return 1;
+
+  err = ccid_open_reader (argc? *argv:NULL, 0, ccid_table, &ccid, NULL);
+  if (err)
+    return 1;
+
+  ccid_dev_scan_finish (ccid_table, idx_max);
+
+  if (!no_poll)
+    ccid_poll (ccid);
+  fputs ("getting ATR ...\n", stderr);
+  err = ccid_get_atr (ccid, NULL, 0, NULL);
+  if (err)
+    {
+      print_error (err);
+      return 1;
+    }
+
+  if (!no_poll)
+    ccid_poll (ccid);
+  fputs ("getting slot status ...\n", stderr);
+  err = ccid_slot_status (ccid, &slotstat, 1);
+  if (err)
+    {
+      print_error (err);
+      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};
+    err = ccid_transceive (ccid,
+                           apdu, sizeof apdu,
+                           result, sizeof result, &resultlen);
+    print_result (err, result, resultlen);
+  }
+
+
+  if (!no_poll)
+    ccid_poll (ccid);
+
+  fputs ("getting OpenPGP DO 0x65 ....\n", stderr);
+  {
+    static unsigned char apdu[] = { 0, 0xCA, 0, 0x65, 254 };
+    err = ccid_transceive (ccid, apdu, sizeof apdu,
+                           result, sizeof result, &resultlen);
+    print_result (err, result, resultlen);
+  }
+
+  if (!no_pinpad)
+    {
+    }
+
+  if (!no_pinpad)
+    {
+      static unsigned char apdu[] = { 0, 0x20, 0, 0x81 };
+      pininfo_t pininfo = { 0, 0, 0 };
+
+      if (ccid_transceive_secure (ccid, apdu, sizeof apdu, &pininfo,
+                                  NULL, 0, NULL))
+        fputs ("can't verify using a PIN-Pad reader\n", stderr);
+      else
+        {
+           fputs ("verifying CHV1 using the PINPad ....\n", stderr);
+
+          err = ccid_transceive_secure (ccid, apdu, sizeof apdu, &pininfo,
+                                        result, sizeof result, &resultlen);
+          print_result (err, 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'};
+        err = ccid_transceive (ccid, apdu, sizeof apdu,
+                               result, sizeof result, &resultlen);
+        print_result (err, result, resultlen);
+      }
+    }
+
+  if (!err)
+    {
+      fputs ("getting OpenPGP DO 0x5E ....\n", stderr);
+      {
+        static unsigned char apdu[] = { 0, 0xCA, 0, 0x5E, 254 };
+        err = ccid_transceive (ccid, apdu, sizeof apdu,
+                               result, sizeof result, &resultlen);
+        print_result (err, result, resultlen);
+      }
+    }
+
+  ccid_close_reader (ccid);
+
+  return 0;
+}
+
+/*
+ * Local Variables:
+ *  compile-command: "gcc -DTEST -DGPGRT_ENABLE_ES_MACROS -DHAVE_NPTH -DUSE_NPTH -Wall -I/usr/include/libusb-1.0 -I/usr/local/include -lusb-1.0 -g ccid-driver.c -lnpth -lgpg-error"
+ * End:
+ */
+#endif /*TEST*/
+#endif /*HAVE_LIBUSB*/