/* Copyright (c) 2019, Red Hat, Inc.
 *
 * Authors:  Jakub Jelen <jjelen@redhat.com>
 *
 * This code is licensed under the GNU LGPL, version 2.1 or later.
 * See the COPYING file in the top-level directory.
 */

#include <stdlib.h>
#include <libcacard.h>

#include "fuzzer.h"

#define ARGS "db=\"sql:%s\" use_hw=no soft=(,Test,CAC,,cert1,cert2,cert3)"
#define APDUBufSize 270

static GMainLoop *loop;
static GThread *thread;
static guint nreaders;
static GMutex mutex;
static GCond cond;

static gpointer
events_thread(gpointer arg)
{
    unsigned int reader_id;
    VEvent *event;

    (void)arg;

    while (1) {
        event = vevent_wait_next_vevent();
        if (event->type == VEVENT_LAST) {
            vevent_delete(event);
            break;
        }
        reader_id = vreader_get_id(event->reader);
        if (reader_id == VSCARD_UNDEFINED_READER_ID) {
            g_mutex_lock(&mutex);
            vreader_set_id(event->reader, nreaders++);
            g_cond_signal(&cond);
            g_mutex_unlock(&mutex);
            reader_id = vreader_get_id(event->reader);
        }
        switch (event->type) {
        case VEVENT_READER_INSERT:
        case VEVENT_READER_REMOVE:
        case VEVENT_CARD_INSERT:
        case VEVENT_CARD_REMOVE:
            break;
        case VEVENT_LAST:
        default:
            g_warn_if_reached();
            break;
        }
        vevent_delete(event);
    }

    return NULL;
}

static void libcacard_init(char *argv0)
{
    VCardEmulOptions *command_line_options = NULL;
    gchar *path = NULL;
    gchar *dbdir = NULL;
    gchar *args = NULL;
    VReader *r;
    VCardEmulError ret;

    /* This is looking for NSS DB dir in the same directory, where the binary
     * is placed if path is absolute, or in the current directory otherwise */
    if (g_path_is_absolute(argv0)) {
        path = g_path_get_dirname(argv0);
    } else {
        gchar *wd = g_get_current_dir();
        gchar *abs = g_build_filename(wd, argv0, NULL);
        g_free(wd);
        path = g_path_get_dirname(abs);
        g_free(abs);
    }
    dbdir = g_build_filename(path, "db", NULL);
    g_free(path);
    args = g_strdup_printf(ARGS, dbdir);

    thread = g_thread_new("fuzz/events", events_thread, NULL);

    command_line_options = vcard_emul_options(args);
    ret = vcard_emul_init(command_line_options);
    g_assert_cmpint(ret, ==, VCARD_EMUL_OK);

    r = vreader_get_reader_by_name("Test");
    g_assert_nonnull(r);
    vreader_free(r); /* get by name ref */

    g_mutex_lock(&mutex);
    while (nreaders == 0)
        g_cond_wait(&cond, &mutex);
    g_mutex_unlock(&mutex);

    g_free(args);
    g_free(dbdir);
}

static void libcacard_finalize(void)
{
    VReader *reader = vreader_get_reader_by_id(0);

    /* This actually still generates events ?? */
    if (reader) /*if /remove didn't run */
        vreader_remove_reader(reader);

    /* This probably supposed to be a event that terminates the loop */
    vevent_queue_vevent(vevent_new(VEVENT_LAST, reader, NULL));

    /* join */
    g_thread_join(thread);

    vreader_free(reader);

    vcard_emul_finalize();
}

int LLVMFuzzerInitialize(int *argc, char ***argv)
{
    VReader *reader;

    (void) argc;

    loop = g_main_loop_new(NULL, TRUE);

    g_debug("Initializing ...");
    libcacard_init(**argv);

    reader = vreader_get_reader_by_id(0);
    if (vreader_card_is_present(reader) != VREADER_OK) {
        g_error("Card inserted but not still not present");
        return -1;
    }

    atexit(libcacard_finalize);

    vreader_free(reader);
    return 0;
}

/* We require at least 2b for length and 4 bytes for simplest APDU (Case 1) */
size_t kMinInputLength = 6;

int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size)
{
    size_t left = Size;
    uint8_t *data = (uint8_t *) Data;
    VReader *reader = NULL;
    int dwRecvLength = APDUBufSize;
    uint8_t pbRecvBuffer[APDUBufSize];

    if (left < kMinInputLength) {
        g_debug("Too short input for APDU");
        return 0;
    }

    reader = vreader_get_reader_by_id(0);
    g_assert_nonnull(reader);

    while (left > 0) {
        VReaderStatus status;
        size_t data_len;

        /* Interpret the fuzzing data as follows:
         * 1 byte       length
         * length bytes data
         */
        data_len = (size_t) data[0];
        data++;
        left--;
        data_len = data_len > left ? left : data_len;

        g_debug("Transfering %zu bytes", data_len);
        status = vreader_xfr_bytes(reader,
                                   data, data_len,
                                   pbRecvBuffer, &dwRecvLength);
        if (status != VREADER_OK) {
            g_debug("Returned %s", status == VREADER_NO_CARD ? "VREADER_NO_CARD" : "VREADER_OUT_OF_MEMORY");
        }
        data += data_len;
        left -= data_len;
    }

    g_debug("Cleaning up");
    vreader_free(reader);

    return 0;
}

/* vim: set ts=4 sw=4 tw=0 noet expandtab: */