test-memcmp.c

#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <strings.h>
#include <stdlib.h>
#include <stdint.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

#define bail(msg, pos)                                         \
  while (1) {                                                  \
                                                               \
    fprintf(stderr, "%s at %u\n", (char *)msg, (uint32_t)pos); \
    return 0;                                                  \
                                                               \
  }

int LLVMFuzzerTestOneInput(uint8_t *buf, size_t len) {

  uint8_t *p8;

  if (len < 32) bail("too short", 0);
  if (memcmp((char *)buf, "0123", 4)) bail("wrong string", 0);
  if (memcmp((char *)buf + 4, "87654321", 8)) bail("wrong string", 4);
  if (memcmp((char *)buf + 12, "ABCDEFHIKLMNOPQR", 16))
    bail("wrong string", 12);
  if (len < 54) bail("too short", 0);
  if (memcmp((char *)buf + 28, "ZYXWVUTSRQPONMLKJIHGFEDCBA", 26))
    bail("wrong string", 28);

  abort();

  return 0;

}

#ifdef __AFL_COMPILER
int main(int argc, char **argv) {

  unsigned char buf[64];
  ssize_t       len;
  int           fd = 0;
  if (argc > 1) fd = open(argv[1], O_RDONLY);

  if ((len = read(fd, buf, sizeof(buf))) <= 0) exit(0);

  LLVMFuzzerTestOneInput(buf, len);
  exit(0);

}

#endif