/*
 * Copyright (c) 2014 Yubico AB
 * All rights reserved.
 *
 * This program 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.
 *
 * This program 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 <http://www.gnu.org/licenses/>.
 *
 * Additional permission under GNU GPL version 3 section 7
 *
 * If you modify this program, or any covered work, by linking or
 * combining it with the OpenSSL project's OpenSSL library (or a
 * modified version of that library), containing parts covered by the
 * terms of the OpenSSL or SSLeay licenses, We grant you additional 
 * permission to convey the resulting work. Corresponding Source for a
 * non-source form of such a combination shall include the source code
 * for the parts of OpenSSL used as well as that of the covered work.
 *
 */

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

#ifdef __APPLE__
#include <PCSC/wintypes.h>
#else
#include <winscard.h>
#endif

#include "cmdline.h"

unsigned const char default_key[] = {
  0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08,
  0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08,
  0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08
};
#define KEY_LEN 24

unsigned const char aid[] = {
  0xa0, 0x00, 0x00, 0x03, 0x08
};
#define AID_LEN 5

union u_APDU {
  struct {
    unsigned char cla;
    unsigned char ins;
    unsigned char p1;
    unsigned char p2;
    unsigned char lc;
    unsigned char data[0xff];
  } st;
  unsigned char raw[0xff + 5];
};

typedef union u_APDU APDU;

void dump_hex(unsigned const char*, unsigned int);
int send_data(SCARDHANDLE*, APDU, unsigned int, unsigned char*, unsigned long*, int);

static bool connect_reader(SCARDHANDLE *card, SCARDCONTEXT *context, const char *wanted, int verbose) {
  unsigned long num_readers;
  unsigned long active_protocol;
  char reader_buf[1024];
  long rc;
  char *reader_ptr;

  rc = SCardEstablishContext(SCARD_SCOPE_SYSTEM, NULL, NULL, context);
  if (rc != SCARD_S_SUCCESS) {
    fprintf (stderr, "error: SCardEstablishContext failed, rc=%08lx\n", rc);
    return false;
  }

  rc = SCardListReaders(*context, NULL, NULL, &num_readers);
  if (rc != SCARD_S_SUCCESS) {
    fprintf (stderr, "error: SCardListReaders failed, rc=%08lx\n", rc);
    SCardReleaseContext(*context);
    return false;
  }

  if (num_readers > sizeof(reader_buf)) {
    num_readers = sizeof(reader_buf);
  }

  rc = SCardListReaders(*context, NULL, reader_buf, &num_readers);
  if (rc != SCARD_S_SUCCESS)
  {
    fprintf (stderr, "error: SCardListReaders failed, rc=%08lx\n", rc);
    SCardReleaseContext(*context);
    return false;
  }

  reader_ptr = reader_buf;
  if(wanted) {
    while(*reader_ptr != '\0') {
      if(strstr(reader_ptr, wanted)) {
        if(verbose) {
          printf("using reader '%s' matching '%s'.\n", reader_ptr, wanted);
        }
        break;
      } else {
        if(verbose) {
          printf("skipping reader '%s' since it doesn't match.\n", reader_ptr);
        }
        reader_ptr += strlen(reader_ptr) + 1;
      }
    }
  }
  if(*reader_ptr == '\0') {
    fprintf (stderr, "error: no useable reader found.\n");
    SCardReleaseContext(*context);
    return false;
  }

  rc = SCardConnect(*context, reader_ptr, SCARD_SHARE_SHARED,
      SCARD_PROTOCOL_T1, card, &active_protocol);
  if(rc != SCARD_S_SUCCESS)
  {
    fprintf (stderr, "error: SCardConnect failed, rc=%08lx\n", rc);
    SCardReleaseContext(*context);
    return false;
  }

  return true;
}

static bool select_applet(SCARDHANDLE *card, int verbose) {
  APDU apdu;
  unsigned char data[0xff];
  unsigned long recv_len = sizeof(data);
  int sw;

  apdu.st.cla = 0x00;
  apdu.st.ins = 0xa4;
  apdu.st.p1 = 0x04;
  apdu.st.p2 = 0x00;
  apdu.st.lc = AID_LEN;
  memcpy(apdu.st.data, aid, AID_LEN);

  sw = send_data(card, apdu, AID_LEN + 5, data, &recv_len, verbose);
  if(sw == 0x9000) {
    return true;
  }

  return false;
}

int send_data(SCARDHANDLE *card, APDU apdu, unsigned int send_len, unsigned char *data, unsigned long *recv_len, int verbose) {
  long rc;
  int sw;

  if(verbose) {
    printf("sending data: (%d bytes)\n", send_len);
    dump_hex(apdu.raw, send_len);
  }
  rc = SCardTransmit(*card, SCARD_PCI_T1, apdu.raw, send_len, NULL, data, recv_len);
  if(rc != SCARD_S_SUCCESS) {
    fprintf (stderr, "error: SCardTransmit failed, rc=%08lx\n", rc);
    return 0;
  }

  if(verbose) {
    printf("received data: (%ld bytes)\n", *recv_len);
    dump_hex(data, *recv_len);
  }
  if(*recv_len >= 2) {
    sw = (data[*recv_len - 2] << 8) | data[*recv_len - 1];
  } else {
    sw = 0;
  }
  return sw;
}

void dump_hex(const unsigned char *buf, unsigned int len) {
  unsigned int i;
  for (i = 0; i < len; i++) {
    printf("0x%02x ", buf[i]);
    if (i % 8 == 7) {
      printf("\n");
    }
  }
  printf("\n");
}

int main(int argc, char *argv[]) {
  struct gengetopt_args_info args_info;
  SCARDHANDLE card;
  SCARDCONTEXT context;

  if (cmdline_parser(argc, argv, &args_info) != 0) {
    return EXIT_FAILURE;
  }

  if (connect_reader(&card, &context, args_info.reader_arg, args_info.verbose_flag) == false) {
    return EXIT_FAILURE;
  }

  if (select_applet(&card, args_info.verbose_flag) == false) {
    return EXIT_FAILURE;
  }

  return EXIT_SUCCESS;
}