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 #ifdef __linux__
  26 # include <sys/sysinfo.h>
  27 #endif
  28
  29 struct globals {
  30         unsigned mem_unit;
  31 #if ENABLE_DESKTOP
  32         unsigned unit_steps;
  33 # define G_unit_steps G.unit_steps
  34 #else
  35 # define G_unit_steps 10
  36 #endif
  37 } FIX_ALIASING;
  38 #define G (*(struct globals*)&bb_common_bufsiz1)
  39 #define INIT_G() do { } while (0)
  40
  41
  42 static unsigned long long scale(unsigned long d)
  43 {
  44         return ((unsigned long long)d * G.mem_unit) >> G_unit_steps;
  45 }
  46
  47
  48 int free_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  49 int free_main(int argc UNUSED_PARAM, char **argv IF_NOT_DESKTOP(UNUSED_PARAM))
  50 {
  51         struct sysinfo info;
  52
  53         INIT_G();
  54
  55 #if ENABLE_DESKTOP
  56         G.unit_steps = 10;
  57         if (argv[1] && argv[1][0] == '-') {
  58                 switch (argv[1][1]) {
  59                 case 'b':
  60                         G.unit_steps = 0;
  61                         break;
  62                 case 'k': /* 2^10 */
  63                         /* G.unit_steps = 10; - already is */
  64                         break;
  65                 case 'm': /* 2^(2*10) */
  66                         G.unit_steps = 20;
  67                         break;
  68                 case 'g': /* 2^(3*10) */
  69                         G.unit_steps = 30;
  70                         break;
  71                 default:
  72                         bb_show_usage();
  73                 }
  74         }
  75 #endif
  76
  77         sysinfo(&info);
  78
  79         /* Kernels prior to 2.4.x will return info.mem_unit==0, so cope... */
  80         G.mem_unit = (info.mem_unit ? info.mem_unit : 1);
  81
  82         printf("     %13s%13s%13s%13s%13s\n",
  83                 "total",
  84                 "used",
  85                 "free",
  86                 "shared", "buffers" /* swap and total don't have these columns */
  87                 /* procps version 3.2.8 also shows "cached" column, but
  88                  * sysinfo() does not provide this value, need to parse
  89                  * /proc/meminfo instead and get "Cached: NNN kB" from there.
  90                  */
  91         );
  92
  93 #define FIELDS_5 "%13llu%13llu%13llu%13llu%13llu\n"
  94 #define FIELDS_3 (FIELDS_5 + 2*6)
  95 #define FIELDS_2 (FIELDS_5 + 3*6)
  96
  97         printf("Mem: ");
  98         printf(FIELDS_5,
  99                 scale(info.totalram),
 100                 scale(info.totalram - info.freeram),
 101                 scale(info.freeram),
 102                 scale(info.sharedram),
 103                 scale(info.bufferram)
 104         );
 105         /* Show alternate, more meaningful busy/free numbers by counting
 106          * buffer cache as free memory (make it "-/+ buffers/cache"
 107          * if/when we add support for "cached" column): */
 108         printf("-/+ buffers:      ");
 109         printf(FIELDS_2,
 110                 scale(info.totalram - info.freeram - info.bufferram),
 111                 scale(info.freeram + info.bufferram)
 112         );
 113 #if BB_MMU
 114         printf("Swap:");
 115         printf(FIELDS_3,
 116                 scale(info.totalswap),
 117                 scale(info.totalswap - info.freeswap),
 118                 scale(info.freeswap)
 119         );
 120 #endif
 121         return EXIT_SUCCESS;
 122 }