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
  26 struct globals {
  27         unsigned mem_unit;
  28 #if ENABLE_DESKTOP
  29         unsigned unit_steps;
  30 # define G_unit_steps G.unit_steps
  31 #else
  32 # define G_unit_steps 10
  33 #endif
  34 } FIX_ALIASING;
  35 #define G (*(struct globals*)&bb_common_bufsiz1)
  36 #define INIT_G() do { } while (0)
  37
  38
  39 static unsigned long long scale(unsigned long d)
  40 {
  41         return ((unsigned long long)d * G.mem_unit) >> G_unit_steps;
  42 }
  43
  44
  45 int free_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  46 int free_main(int argc UNUSED_PARAM, char **argv IF_NOT_DESKTOP(UNUSED_PARAM))
  47 {
  48         struct sysinfo info;
  49
  50         INIT_G();
  51
  52 #if ENABLE_DESKTOP
  53         G.unit_steps = 10;
  54         if (argv[1] && argv[1][0] == '-') {
  55                 switch (argv[1][1]) {
  56                 case 'b':
  57                         G.unit_steps = 0;
  58                         break;
  59                 case 'k': /* 2^10 */
  60                         /* G.unit_steps = 10; - already is */
  61                         break;
  62                 case 'm': /* 2^(2*10) */
  63                         G.unit_steps = 20;
  64                         break;
  65                 case 'g': /* 2^(3*10) */
  66                         G.unit_steps = 30;
  67                         break;
  68                 default:
  69                         bb_show_usage();
  70                 }
  71         }
  72 #endif
  73
  74         sysinfo(&info);
  75
  76         /* Kernels prior to 2.4.x will return info.mem_unit==0, so cope... */
  77         G.mem_unit = (info.mem_unit ? info.mem_unit : 1);
  78
  79         printf("     %13s%13s%13s%13s%13s\n",
  80                 "total",
  81                 "used",
  82                 "free",
  83                 "shared", "buffers" /* swap and total don't have these columns */
  84                 /* procps version 3.2.8 also shows "cached" column, but
  85                  * sysinfo() does not provide this value, need to parse
  86                  * /proc/meminfo instead and get "Cached: NNN kB" from there.
  87                  */
  88         );
  89
  90 #define FIELDS_5 "%13llu%13llu%13llu%13llu%13llu\n"
  91 #define FIELDS_3 (FIELDS_5 + 2*6)
  92 #define FIELDS_2 (FIELDS_5 + 3*6)
  93
  94         printf("Mem: ");
  95         printf(FIELDS_5,
  96                 scale(info.totalram),
  97                 scale(info.totalram - info.freeram),
  98                 scale(info.freeram),
  99                 scale(info.sharedram),
 100                 scale(info.bufferram)
 101         );
 102         /* Show alternate, more meaningful busy/free numbers by counting
 103          * buffer cache as free memory (make it "-/+ buffers/cache"
 104          * if/when we add support for "cached" column): */
 105         printf("-/+ buffers:      ");
 106         printf(FIELDS_2,
 107                 scale(info.totalram - info.freeram - info.bufferram),
 108                 scale(info.freeram + info.bufferram)
 109         );
 110 #if BB_MMU
 111         printf("Swap:");
 112         printf(FIELDS_3,
 113                 scale(info.totalswap),
 114                 scale(info.totalswap - info.freeswap),
 115                 scale(info.freeswap)
 116         );
 117 #endif
 118         return EXIT_SUCCESS;
 119 }