Bad file header cleaner thing

#include <dirent.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>

void check_file(const char *path) {
  FILE *file = fopen(path, "rb");
  if(!file)
    return;
  fseek(file, 0, SEEK_END);
  int size = ftell(file);
  rewind(file);

  unsigned char *buffer = (char*)malloc (sizeof(char)*size);
  if(!buffer)
    goto error;
  int result = fread(buffer, 1, size, file);
  if(result != size)
    goto error;

  int bad = buffer[14] || buffer[15];

  if(bad) {
    printf("Fixing bad header: %s\n", path);
    for(int i=0; i<15; i++)
      printf("%.2X ", buffer[i]);
    putchar('\n');

    fclose(file);
    file = fopen(path, "wb");
    if(!file) {
      puts("Couldn't open the file for writing to fix it though");
      goto error;
    }
    for(int i=7; i<16; i++) // clear out the last 9 bytes of the header
      buffer[i] = 0;
    fwrite(buffer, sizeof(char), size, file);
  }

error:
  free(buffer);
  if(file)
    fclose(file);
}

int is_directory(const char *path) {
  struct stat statbuf;
  if (stat(path, &statbuf) != 0)
      return 0;
  return S_ISDIR(statbuf.st_mode);
}

void scan(const char *name) {
  DIR *d;
  struct dirent *dir;
  d = opendir(name);
  if(d) {
    while ((dir = readdir(d)) != NULL) {
       if(dir->d_name[0] == '.')
         continue;
       char full_path[500];
       sprintf(full_path, "%s/%s", name, dir->d_name);
       if(is_directory(full_path)) {
         scan(full_path);
         continue;
       }
       char *extension = strrchr(dir->d_name, '.');
       if(!extension)
         continue;
       if(strcasecmp(extension+1, "nes"))
         continue;

       check_file(full_path);
    }
    closedir(d);
  }
}

int main(int argc, char *argv[]) {
  scan(".");
  return 0;
}