LXR linux-old/kernel/info.c

   1/*
   2 * linux/kernel/info.c
   3 *
   4 * Copyright (C) 1992 Darren Senn
   5 */
   6
   7/* This implements the sysinfo() system call */
   8
   9#include <linux/mm.h>
  10#include <linux/unistd.h>
  11#include <linux/swap.h>
  12#include <linux/smp_lock.h>
  13
  14#include <asm/uaccess.h>
  15
  16asmlinkage long sys_sysinfo(struct sysinfo *info)
  17{
  18        struct sysinfo val;
  19
  20        memset((char *)&val, 0, sizeof(struct sysinfo));
  21
  22        cli();
  23        val.uptime = jiffies / HZ;
  24
  25        val.loads[0] = avenrun[0] << (SI_LOAD_SHIFT - FSHIFT);
  26        val.loads[1] = avenrun[1] << (SI_LOAD_SHIFT - FSHIFT);
  27        val.loads[2] = avenrun[2] << (SI_LOAD_SHIFT - FSHIFT);
  28
  29        val.procs = nr_threads-1;
  30        sti();
  31
  32        si_meminfo(&val);
  33        si_swapinfo(&val);
  34
  35        {
  36                unsigned long mem_total, sav_total;
  37                unsigned int mem_unit, bitcount;
  38
  39                /* If the sum of all the available memory (i.e. ram + swap)
  40                 * is less than can be stored in a 32 bit unsigned long then
  41                 * we can be binary compatible with 2.2.x kernels.  If not,
  42                 * well, in that case 2.2.x was broken anyways...
  43                 *
  44                 *  -Erik Andersen <andersee@debian.org> */
  45
  46                mem_total = val.totalram + val.totalswap;
  47                if (mem_total < val.totalram || mem_total < val.totalswap)
  48                        goto out;
  49                bitcount = 0;
  50                mem_unit = val.mem_unit;
  51                while (mem_unit > 1) {
  52                        bitcount++;
  53                        mem_unit >>= 1;
  54                        sav_total = mem_total;
  55                        mem_total <<= 1;
  56                        if (mem_total < sav_total)
  57                                goto out;
  58                }
  59
  60                /* If mem_total did not overflow, multiply all memory values by
  61                 * val.mem_unit and set it to 1.  This leaves things compatible
  62                 * with 2.2.x, and also retains compatibility with earlier 2.4.x
  63                 * kernels...  */
  64
  65                val.mem_unit = 1;
  66                val.totalram <<= bitcount;
  67                val.freeram <<= bitcount;
  68                val.sharedram <<= bitcount;
  69                val.bufferram <<= bitcount;
  70                val.totalswap <<= bitcount;
  71                val.freeswap <<= bitcount;
  72                val.totalhigh <<= bitcount;
  73                val.freehigh <<= bitcount;
  74        }
  75out:
  76        if (copy_to_user(info, &val, sizeof(struct sysinfo)))
  77                return -EFAULT;
  78        return 0;
  79}
  80