Reserve bad memory addresses before another app uses them

badmem.c

#include <sys/mman.h>
#include <stdio.h>
#include <stdlib.h>

// 512 bytes of padding on each side
#define PADDING 0x200

int main(int argc, char *argv[]) {
  if (argc < 2) {
    printf("Usage: badmem <badmemfile.csv>\n");
    return 1;
  }

  FILE *fp = fopen(argv[1], "r");

  if (fp == NULL) {
    printf("Could not find file: %s\n", argv[1]);
    return 1;
  }

  char line_buffer[1024];

  int result_code = 0;

  while(fgets(line_buffer, 1024, fp) != NULL) {
    long long address = strtoll(line_buffer, NULL, 16);
    long long start = address - PADDING;
    void *result = mmap((void *)start, PADDING * 2, PROT_NONE, MAP_ANON | MAP_SHARED, 0, 0);
    if (result == MAP_FAILED) {
      printf("Error executing mmap on address = %llx", address);
      result_code = 1;
    }
  }

  return result_code;
}