OpenBSD equivalent of `free' Linux command. Shows memory usage.

free.c

/*
 * $Id: $
 *
 * Module:  free -- description
 * Created: 15-SEP-2008 17:56
 * Author:  tmr
 */

#include <stdio.h>
#include <unistd.h>
#include <sys/param.h>
#include <sys/sysctl.h>

typedef struct {
  unsigned pages;
  unsigned kbytes;
} MemSizeItem;

typedef struct {
  MemSizeItem free;
  MemSizeItem used;
  MemSizeItem total;
} MemInfo;

unsigned page2kbyte (unsigned pageCnt)
  { return (pageCnt * getpagesize ()) >> 10; }

void getMemInfo (MemInfo * mem) {

  /* statistics about the UVM memory *
   * management system.              */
  int mib [] = { CTL_VM, VM_UVMEXP };
  const int pagesize = getpagesize ();
  struct uvmexp our_uvmexp;
  size_t size = sizeof (our_uvmexp);

  if (sysctl (mib, 2, &our_uvmexp, &size, NULL, 0) < 0) {
    fprintf (stderr, "cannot get memory info!");
    return;
  }

  mem->total.pages = our_uvmexp.npages;
  mem->free.pages  = our_uvmexp.free +our_uvmexp.inactive;
  mem->used.pages  = mem->total.pages -mem->free.pages;

  mem->total.kbytes = page2kbyte (mem->total.pages);
  mem->used.kbytes  = page2kbyte (mem->used.pages);
  mem->free.kbytes  = page2kbyte (mem->free.pages);
}

#define FORMAT(name,item) \
  printf ("%8s:  %8d pages  ~=%8d kBytes\n", \
          name, item.pages, item.kbytes);

int main (int argc, char * argv []) {

  MemInfo mem;
  getMemInfo (&mem);

  FORMAT ("Total", mem.total);
  FORMAT ("Used",  mem.used);
  FORMAT ("Free",  mem.free);

  return (0);
}

// vim: fdm=syntax:fdn=1:tw=74:ts=2:syn=c