tool to quickly send some APDUs to a smartcard using PC/SC

apdusender.c

#include <stdio.h>
#include <PCSC/winscard.h>
#include <string.h>
#include <unistd.h>
#include <stdlib.h>
#include <getopt.h>

const struct option options[] = {
	{"reader", required_argument, 0, 'r'},
	{"apdu", required_argument, 0, 'a'},
	{NULL, 0, 0, 0},
};

static LPCSCARD_IO_REQUEST ioreq;

SCARDHANDLE openReader(SCARDCONTEXT ctx, int which, SCARDHANDLE oldhandle) {
	static LPSTR readers = NULL;
	LPSTR ptr;
	DWORD readerlen = SCARD_AUTOALLOCATE;
	int counter = 0;
	LONG r;
	SCARDHANDLE handle;
	DWORD active;

	if(!readers) {
		SCardListReaders(ctx, NULL, (LPSTR)&readers, &readerlen);
	}
	if(oldhandle) {
		SCardDisconnect(oldhandle, SCARD_LEAVE_CARD);
	}
	ptr = readers;
	while(*ptr) {
		if(which < 0 || counter == which) {
			r = SCardConnect(ctx, ptr, SCARD_SHARE_EXCLUSIVE, SCARD_PROTOCOL_T0 | SCARD_PROTOCOL_T1, &handle, &active);

			if(r != SCARD_S_SUCCESS) {
				if(counter == which) {
					fprintf(stderr, "E: Could not connect to card reader %d %s: %x\n", which, ptr, r);
					exit(EXIT_FAILURE);
				}
			} else {
				printf("Connected to smart card reader %s\n", ptr);
				ioreq = (active == SCARD_PROTOCOL_T0 ? SCARD_PCI_T0 : SCARD_PCI_T1);
				return handle;
			}
		}
		ptr += strlen(ptr) + 1;
		counter++;
	}
	fprintf(stderr, "E: Could not find a suitable reader\n");
	exit(EXIT_FAILURE);
}

void performApdu(SCARDHANDLE h, char *apduString) {
	size_t len = strlen(apduString);
	char apduBytes[(len/2) + 1];
	unsigned char recvBytes[300] = {0};
	DWORD recvlen = sizeof(recvBytes) - 1;
	LONG r;

	printf("Attempting to send APDU %s\n", apduString);
	apduBytes[len/2] = 0;
	for(int i=0; i<len/2; i++) {
		char hexbyte[3] = {0};
		char *loc;
		hexbyte[0] = apduString[i*2];
		hexbyte[1] = apduString[i*2+1];
		apduBytes[i] = strtol(hexbyte, &loc, 16);
		if(loc != &(hexbyte[2])) {
			fprintf(stderr, "E: Invalid hexadecimal character found, cannot continue\n");
			exit(EXIT_FAILURE);
		}
	}
	r = SCardTransmit(h, ioreq, apduBytes, (len / 2), NULL, recvBytes, &recvlen);
	if(r != SCARD_S_SUCCESS) {
		fprintf(stderr, "E: Could not transmit %s: %x\n", apduString, r);
		exit(EXIT_FAILURE);
	}
	printf("SW12: %02X %02X\n", recvBytes[recvlen - 2], recvBytes[recvlen - 1]);
	if(recvlen > 2) {
		int i;
		for(i = 0; i <= (recvlen - 2) / 8; i++) {
			for(int j = 0; j < 8 && i * 8 + j < (recvlen - 2); j++) {
				printf("%02X ", recvBytes[i * 8 + j]);
			}
			printf(i % 2 ? "\n" : " ");
		}
		if(i % 2) {
			printf("\n");
		}
	}
}

int main(int argc, char**argv) {
	SCARDCONTEXT ctx;
	SCARDHANDLE handle = 0;
	int c;

	SCardEstablishContext(SCARD_SCOPE_USER, NULL, NULL, &ctx);

	while((c = getopt_long(argc, argv, "a:r:", options, &optind)) > 0) {
		switch(c) {
		case 'a':
			if(!handle) {
				handle = openReader(ctx, -1, 0);
			}
			performApdu(handle, optarg);
			break;
		case 'r':
			handle = openReader(ctx, strtol(optarg, NULL, 10), handle);
			break;
		}
	}

	return 0;
}