#include <stdlib.h>#include <stdio.h>#include <fcntl.h>#include <ffi.h>#include "fficonfig.h"#define MAX_ARGS 256#define CHECK(x) (!(x) ? abort() : (void)0)/* Prefer MAP_ANON(YMOUS) to /dev/zero, since we don't need to keep a   file open.  */#ifdef HAVE_MMAP_ANON# undef HAVE_MMAP_DEV_ZERO# include <sys/mman.h># ifndef MAP_FAILED#  define MAP_FAILED -1# endif# if !defined (MAP_ANONYMOUS) && defined (MAP_ANON)#  define MAP_ANONYMOUS MAP_ANON# endif# define USING_MMAP#endif#ifdef HAVE_MMAP_DEV_ZERO# include <sys/mman.h># ifndef MAP_FAILED#  define MAP_FAILED -1# endif# define USING_MMAP#endif#ifdef USING_MMAPstatic inline void *allocate_mmap (size_t size){  void *page;#if defined (HAVE_MMAP_DEV_ZERO)  static int dev_zero_fd = -1;#endif#ifdef HAVE_MMAP_DEV_ZERO  if (dev_zero_fd == -1)    {      dev_zero_fd = open ("/dev/zero", O_RDONLY);      if (dev_zero_fd == -1)	{	  perror ("open /dev/zero: %m");	  exit (1);	}    }#endif#ifdef HAVE_MMAP_ANON  page = mmap (NULL, size, PROT_READ | PROT_WRITE | PROT_EXEC,	       MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);#endif#ifdef HAVE_MMAP_DEV_ZERO  page = mmap (NULL, size, PROT_READ | PROT_WRITE | PROT_EXEC,	       MAP_PRIVATE, dev_zero_fd, 0);#endif  if (page == MAP_FAILED)    {      perror ("virtual memory exhausted");      exit (1);    }  return page;}#endif