procps/free.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * Mini free implementation for busybox
   4  *
   5  * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
   6  *
   7  * Licensed under GPLv2, see file LICENSE in this source tree.
   8  */
   9
  10 /* getopt not needed */
  11
  12 //usage:#define free_trivial_usage
  13 //usage:       "" IF_DESKTOP("[-b/k/m/g]")
  14 //usage:#define free_full_usage "\n\n"
  15 //usage:       "Display the amount of free and used system memory"
  16 //usage:
  17 //usage:#define free_example_usage
  18 //usage:       "$ free\n"
  19 //usage:       "              total         used         free       shared      buffers\n"
  20 //usage:       "  Mem:       257628       248724         8904        59644        93124\n"
  21 //usage:       " Swap:       128516         8404       120112\n"
  22 //usage:       "Total:       386144       257128       129016\n"
  23
  24 #include "libbb.h"
  25 #include "common_bufsiz.h"
  26 #ifdef __linux__
  27 # include <sys/sysinfo.h>
  28 #endif
  29
  30 struct globals {
  31         unsigned mem_unit;
  32 #if ENABLE_DESKTOP
  33         unsigned unit_steps;
  34 # define G_unit_steps G.unit_steps
  35 #else
  36 # define G_unit_steps 10
  37 #endif
  38 } FIX_ALIASING;
  39 #define G (*(struct globals*)bb_common_bufsiz1)
  40 #define INIT_G() do { setup_common_bufsiz(); } while (0)
  41
  42
  43 static unsigned long long scale(unsigned long d)
  44 {
  45         return ((unsigned long long)d * G.mem_unit) >> G_unit_steps;
  46 }
  47
  48 static unsigned long parse_cached_kb(void)
  49 {
  50         char buf[60]; /* actual lines we expect are ~30 chars or less */
  51         FILE *fp;
  52         unsigned long cached = 0;
  53
  54         fp = xfopen_for_read("/proc/meminfo");
  55         while (fgets(buf, sizeof(buf), fp) != NULL) {
  56                 if (sscanf(buf, "Cached: %lu %*s\n", &cached) == 1)
  57                         break;
  58         }
  59         if (ENABLE_FEATURE_CLEAN_UP)
  60                 fclose(fp);
  61
  62         return cached;
  63 }
  64
  65 int free_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  66 int free_main(int argc UNUSED_PARAM, char **argv IF_NOT_DESKTOP(UNUSED_PARAM))
  67 {
  68         struct sysinfo info;
  69         unsigned long long cached;
  70
  71         INIT_G();
  72
  73 #if ENABLE_DESKTOP
  74         G.unit_steps = 10;
  75         if (argv[1] && argv[1][0] == '-') {
  76                 switch (argv[1][1]) {
  77                 case 'b':
  78                         G.unit_steps = 0;
  79                         break;
  80                 case 'k': /* 2^10 */
  81                         /* G.unit_steps = 10; - already is */
  82                         break;
  83                 case 'm': /* 2^(2*10) */
  84                         G.unit_steps = 20;
  85                         break;
  86                 case 'g': /* 2^(3*10) */
  87                         G.unit_steps = 30;
  88                         break;
  89                 default:
  90                         bb_show_usage();
  91                 }
  92         }
  93 #endif
  94         printf("       %11s%11s%11s%11s%11s%11s\n"
  95         "Mem:   ",
  96                 "total",
  97                 "used",
  98                 "free",
  99                 "shared", "buffers", "cached" /* swap and total don't have these columns */
 100         );
 101
 102         sysinfo(&info);
 103         /* Kernels prior to 2.4.x will return info.mem_unit==0, so cope... */
 104         G.mem_unit = (info.mem_unit ? info.mem_unit : 1);
 105         /* Extract cached from /proc/meminfo and convert to mem_units */
 106         cached = ((unsigned long long) parse_cached_kb() * 1024) / G.mem_unit;
 107
 108 #define FIELDS_6 "%11llu%11llu%11llu%11llu%11llu%11llu\n"
 109 #define FIELDS_3 (FIELDS_6 + 3*6)
 110 #define FIELDS_2 (FIELDS_6 + 4*6)
 111
 112         printf(FIELDS_6,
 113                 scale(info.totalram),                //total
 114                 scale(info.totalram - info.freeram), //used
 115                 scale(info.freeram),                 //free
 116                 scale(info.sharedram),               //shared
 117                 scale(info.bufferram),               //buffers
 118                 scale(cached)                        //cached
 119         );
 120         /* Show alternate, more meaningful busy/free numbers by counting
 121          * buffer cache as free memory. */
 122         printf("-/+ buffers/cache:");
 123         cached += info.freeram;
 124         cached += info.bufferram;
 125         printf(FIELDS_2,
 126                 scale(info.totalram - cached), //used
 127                 scale(cached)                  //free
 128         );
 129 #if BB_MMU
 130         printf("Swap:  ");
 131         printf(FIELDS_3,
 132                 scale(info.totalswap),                 //total
 133                 scale(info.totalswap - info.freeswap), //used
 134                 scale(info.freeswap)                   //free
 135         );
 136 #endif
 137         return EXIT_SUCCESS;
 138 }