/* Copyright 2020 Google Inc.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

      http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

#include <stdint.h>
#include <stddef.h>
#include <stdlib.h>
#include <stdio.h>
#include <stdbool.h>
#include <ftw.h>

#define INCLUDED_BY_MAIN_MODULE 1
#include "config.h"
#include "gpg.h"
#include "../common/types.h"
#include "../common/iobuf.h"
#include "keydb.h"
#include "keyedit.h"
#include "../common/util.h"
#include "main.h"
#include "call-dirmngr.h"
#include "trustdb.h"

#include <sys/stat.h>
#include <fcntl.h>
#include <sys/types.h>
#include <unistd.h>
#include <sys/mount.h>

static bool initialized = false;
ctrl_t ctrlGlobal;
int fd;
char *filename;

//hack not to include gpg.c which has main function
int g10_errors_seen = 0;

void
g10_exit( int rc )
{
    gcry_control (GCRYCTL_UPDATE_RANDOM_SEED_FILE);
    gcry_control (GCRYCTL_TERM_SECMEM );
    exit (rc);
}

static void
gpg_deinit_default_ctrl (ctrl_t ctrl)
{
#ifdef USE_TOFU
    tofu_closedbs (ctrl);
#endif
    gpg_dirmngr_deinit_session_data (ctrl);

    keydb_release (ctrl->cached_getkey_kdb);
}

static void
my_gcry_logger (void *dummy, int level, const char *format, va_list arg_ptr)
{
    return;
}

static int unlink_cb(const char *fpath, const struct stat *sb, int typeflag)
{
    if (typeflag == FTW_F){
        unlink(fpath);
    }
    return 0;
}

static void rmrfdir(char *path)
{
    ftw(path, unlink_cb, 16);
    if (rmdir(path) != 0) {
        printf("failed rmdir, errno=%d\n", errno);
    }
}

// 65kb should be enough ;-)
#define MAX_LEN 0x10000

int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {

    if (! initialized) {
        ctrlGlobal = (ctrl_t) malloc(sizeof(*ctrlGlobal));
        if (!ctrlGlobal) {
            exit(1);
        }
        //deletes previous tmp dir and (re)create it as a ramfs
        //system("umount /tmp/fuzzdirdecrypt");
        rmrfdir("/tmp/fuzzdirdecrypt");
        mkdir("/tmp/fuzzdirdecrypt", 0700);
        //system("mount -t tmpfs -o size=64M tmpfs /tmp/fuzzdirdecrypt");
        filename=strdup("/tmp/fuzzdirdecrypt/fuzz.gpg");
        if (!filename) {
            free(ctrlGlobal);
            return 0;
        }
        fd = open("/tmp/fuzzdirdecrypt/fuzz.gpg", O_RDWR | O_CREAT, 0600);
        if (fd == -1) {
            free(ctrlGlobal);
            free(filename);
            return 0;
        }
        gnupg_set_homedir("/tmp/fuzzdirdecrypt/");
        if (keydb_add_resource ("pubring" EXTSEP_S GPGEXT_GPG,
                                KEYDB_RESOURCE_FLAG_DEFAULT) != GPG_ERR_NO_ERROR) {
            free(filename);
            free(ctrlGlobal);
            close(fd);
            return 0;
        }
        if (setup_trustdb (1, NULL) != GPG_ERR_NO_ERROR) {
            free(filename);
            free(ctrlGlobal);
            close(fd);
            return 0;
        }
        //populate /tmp/fuzzdirdecrypt/ as homedir ~/.gnupg
        strlist_t sl = NULL;
        public_key_list (ctrlGlobal, sl, 0, 0);
        free_strlist(sl);
        //no output for stderr
        log_set_file("/dev/null");
        gcry_set_log_handler (my_gcry_logger, NULL);
        gnupg_initialize_compliance (GNUPG_MODULE_NAME_GPG);
        //overwrite output file
        opt.batch = 1;
        opt.answer_yes = 1;
        initialized = true;
    }

    memset(ctrlGlobal, 0, sizeof(*ctrlGlobal));
    ctrlGlobal->magic = SERVER_CONTROL_MAGIC;
    if (Size > MAX_LEN) {
        // limit maximum size to avoid long computing times
        Size = MAX_LEN;
    }

    if (ftruncate(fd, Size) == -1) {
        return 0;
    }
    if (lseek (fd, 0, SEEK_SET) < 0) {
        return 0;
    }
    if (write (fd, Data, Size) != Size) {
        return 0;
    }

    decrypt_messages(ctrlGlobal, 1, &filename);
    gpg_deinit_default_ctrl (ctrlGlobal);
    memset(ctrlGlobal, 0, sizeof(*ctrlGlobal));
    ctrlGlobal->magic = SERVER_CONTROL_MAGIC;
    decrypt_message(ctrlGlobal, filename);
    gpg_deinit_default_ctrl (ctrlGlobal);

    return 0;
}