c/tests/fuzz/StandaloneFuzzTargetInit.c

/*
 *
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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 <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "libFuzzingEngine.h"

/*
 * Use this to implement response file:
 * - Check if there is one file mentioned and its name starts with '@'
 * - If so then read the file line by line making up the new argv
 * - Modify argc/argv then return.
 *
 * Problem: Somehow need to free buf and nargv to avoid sanitizer warnings
 */

/* Free allocated memory at program exit to avoid the leak sanitizer complaining  */
static char *buf = 0;
static char **nargv = 0;

static void freeall(void)
{
  free(buf);
  free(nargv);
}

int LLVMFuzzerInitialize(int *argc, char ***argv)
{
  if (*argc==2 && (*argv)[1][0]=='@') {
    const char* rfilename = (*argv)[1]+1;

    /* Read entire file into memory */
    fprintf(stderr, "Reading response file: %s\n", rfilename);
    FILE *f = fopen(rfilename, "rb");
    assert(f);
    fseek(f, 0, SEEK_END);
    size_t len = ftell(f);
    fseek(f, 0, SEEK_SET);
    buf = (char*)malloc(len+1);
    size_t n_read = fread(buf, 1, len, f);
    fclose(f);
    assert(n_read == len);
    buf[len] = '\0';

    /* scan file counting lines and replacing line ends with \0 */
    int line = 0;
    char *p = buf;
    while (p<&buf[len]) {
      p += strcspn(p, "\n\r ");
      *p++ = '\0';
      line +=1;
    };

    fprintf(stderr, "        response file: (%zd bytes, %d lines)\n", n_read, line);

    /* scan again putting each line into the argv array */
    nargv = (char**) calloc(line+1, sizeof(p));

    p = buf;
    line = 1;
    do {
        char* s = p;
        int l = strlen(p);
        p += l+1;
        if (l>0) nargv[line++] = s;
    } while (p<&buf[len]);

    int nargc = line;
    *argc = nargc;
    *argv = nargv;
    atexit(&freeall);
  }
  return 0;
}