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 static unsigned long parse_cached_kb(void)
  48 {
  49         char buf[60]; /* actual lines we expect are ~30 chars or less */
  50         FILE *fp;
  51         unsigned long cached = 0;
  52
  53         fp = xfopen_for_read("/proc/meminfo");
  54         while (fgets(buf, sizeof(buf), fp) != NULL) {
  55                 if (sscanf(buf, "Cached: %lu %*s\n", &cached) == 1)
  56                         break;
  57         }
  58         if (ENABLE_FEATURE_CLEAN_UP)
  59                 fclose(fp);
  60
  61         return cached;
  62 }
  63
  64 int free_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  65 int free_main(int argc UNUSED_PARAM, char **argv IF_NOT_DESKTOP(UNUSED_PARAM))
  66 {
  67         struct sysinfo info;
  68         unsigned long long cached;
  69
  70         INIT_G();
  71
  72 #if ENABLE_DESKTOP
  73         G.unit_steps = 10;
  74         if (argv[1] && argv[1][0] == '-') {
  75                 switch (argv[1][1]) {
  76                 case 'b':
  77                         G.unit_steps = 0;
  78                         break;
  79                 case 'k': /* 2^10 */
  80                         /* G.unit_steps = 10; - already is */
  81                         break;
  82                 case 'm': /* 2^(2*10) */
  83                         G.unit_steps = 20;
  84                         break;
  85                 case 'g': /* 2^(3*10) */
  86                         G.unit_steps = 30;
  87                         break;
  88                 default:
  89                         bb_show_usage();
  90                 }
  91         }
  92 #endif
  93         printf("       %11s%11s%11s%11s%11s%11s\n"
  94         "Mem:   ",
  95                 "total",
  96                 "used",
  97                 "free",
  98                 "shared", "buffers", "cached" /* swap and total don't have these columns */
  99         );
 100
 101         sysinfo(&info);
 102         /* Kernels prior to 2.4.x will return info.mem_unit==0, so cope... */
 103         G.mem_unit = (info.mem_unit ? info.mem_unit : 1);
 104         /* Extract cached from /proc/meminfo and convert to mem_units */
 105         cached = ((unsigned long long) parse_cached_kb() * 1024) / G.mem_unit;
 106
 107 #define FIELDS_6 "%11llu%11llu%11llu%11llu%11llu%11llu\n"
 108 #define FIELDS_3 (FIELDS_6 + 3*6)
 109 #define FIELDS_2 (FIELDS_6 + 4*6)
 110
 111         printf(FIELDS_6,
 112                 scale(info.totalram),                //total
 113                 scale(info.totalram - info.freeram), //used
 114                 scale(info.freeram),                 //free
 115                 scale(info.sharedram),               //shared
 116                 scale(info.bufferram),               //buffers
 117                 scale(cached)                        //cached
 118         );
 119         /* Show alternate, more meaningful busy/free numbers by counting
 120          * buffer cache as free memory. */
 121         printf("-/+ buffers/cache:");
 122         cached += info.freeram;
 123         cached += info.bufferram;
 124         printf(FIELDS_2,
 125                 scale(info.totalram - cached), //used
 126                 scale(cached)                  //free
 127         );
 128 #if BB_MMU
 129         printf("Swap:  ");
 130         printf(FIELDS_3,
 131                 scale(info.totalswap),                 //total
 132                 scale(info.totalswap - info.freeswap), //used
 133                 scale(info.freeswap)                   //free
 134         );
 135 #endif
 136         return EXIT_SUCCESS;
 137 }