/*
    mincore - counts noncached pages in files
    Copyright (C) 2005  Kasper Dupont

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    with permission from the author any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/

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

/* Returns number of nonresident pages in a file. */

int fincore(int fd)
{
  int r=0;
  unsigned i;
  uint8_t *vec;
  void * mapaddr;
  struct stat stbuf;
  off_t size;
  size_t veclen;
  int pagesize=getpagesize();

  if (pagesize<1) return -1;
  if (fstat(fd,&stbuf)) return -1;
  if ((size=stbuf.st_size)<1) return 0; /* Empty file */

  veclen=((size-1)/pagesize)+1;
  vec=malloc(veclen);
  if (!vec) return -1;

  mapaddr=mmap(NULL,size,PROT_READ,MAP_SHARED,fd,0);
  if (mapaddr == MAP_FAILED) {
    r=-1;
  } else {
    if (mincore(mapaddr,stbuf.st_size,vec)) {
      r=-1;
    } else {
      for (i=0;i<veclen;++i)
	r+=!(vec[i]&1);
    }
    munmap(mapaddr,size);
  }
  free(vec);

  return r;
}

int main(int argc, char ** argv)
{
  while (*++argv) {
    int fd=open(*argv,O_RDONLY);
    if (fd==-1) {
      perror(*argv);
    } else {
      int r=fincore(fd);
      if (r<0) {
	perror(*argv);
      } else {
	printf("%s: %d\n",*argv,r);
      }
      close(fd);
    }
  }
  return 0;
}