/*
 * Copyright (c) 2015, NORDUnet A/S.
 * See LICENSE for licensing information.
 */

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

#include "hsmhelper.h"
#include "erlport.h"

static long
parseslot(char *slotstring)
{
    char *endptr = NULL;

    if (slotstring[0] == '\0') {
        errx(1, "no slot given");
    }

    long slot = strtol(slotstring, &endptr, 10);

    if (endptr[0] != '\0') {
        errx(1, "not a valid slot number: %s", slotstring);
    }

    return slot;
}

static void
loop(CK_SESSION_HANDLE hSession, CK_OBJECT_HANDLE hKey,
     CK_MECHANISM_TYPE mechanism)
{
    unsigned char buf[10000];
    unsigned char signature[2048];
    ssize_t len;

    while ((len = read_command(buf, sizeof(buf), 4)) > 0) {
        unsigned long signatureLen = sizeof(signature);
        sign(hSession, hKey, buf, len, signature, &signatureLen, mechanism);
        write_reply(signature, signatureLen, 4);
    }
}

#define MAX_PIN_SIZE 1000

char *
read_pin(char *filename)
{
    FILE *pin_file;
    char *result;

    pin_file = fopen(filename, "r");

    if (pin_file == NULL) {
        return NULL;
    }

    char *pin = malloc(MAX_PIN_SIZE);
    result = fgets(pin, MAX_PIN_SIZE, pin_file);

    if (result == NULL) {
        free(pin);
        fclose(pin_file);
        return NULL;
    }

    size_t newlinepos = strcspn(result, "\r\n");
    pin[newlinepos] = '\0';

    fclose(pin_file);

    return pin;
}

int
main(int argc, char *argv[])
{
    if (argc < 6) {
        errx(1, "usage: %s <pkcs11library> <slot> rsa|ecdsa <keyname> <pin>", argv[0]);
    }

    char *library_path = argv[1];
    char *slotstring = argv[2];
    char *keytype = argv[3];
    char *keyname = argv[4];
    char *pin_or_file = argv[5];

    char *pin;

    if (pin_or_file[0] == '@') {
        pin = read_pin(pin_or_file + 1);
    } else {
        pin = strdup(pin_or_file);
    }

    if (pin == NULL) {
        errx(1, "Could not read pin");
    }

    init(library_path);

    long slot = parseslot(slotstring);

    CK_MECHANISM_TYPE mechanism;

    if (strcmp(keytype, "ecdsa") == 0) {
        mechanism = CKM_ECDSA;
    } else if (strcmp(keytype, "rsa") == 0) {
        mechanism = CKM_SHA256_RSA_PKCS;
    } else {
        errx(1, "invalid key type: %s", keytype);
    }

    CK_SESSION_HANDLE hSession = open_session(slot);

    login(hSession, pin);

    CK_OBJECT_HANDLE hKey = find_key(hSession, CKO_PRIVATE_KEY, keyname);

    loop(hSession, hKey, mechanism);

    free(pin);

    return 0;
}