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 //config:config FREE
  10 //config:       bool "free (2.4 kb)"
  11 //config:       default y
  12 //config:       select PLATFORM_LINUX #sysinfo()
  13 //config:       help
  14 //config:       free displays the total amount of free and used physical and swap
  15 //config:       memory in the system, as well as the buffers used by the kernel.
  16 //config:       The shared memory column should be ignored; it is obsolete.
  17
  18 //applet:IF_FREE(APPLET(free, BB_DIR_USR_BIN, BB_SUID_DROP))
  19
  20 //kbuild:lib-$(CONFIG_FREE) += free.o
  21
  22 //usage:#define free_trivial_usage
  23 //usage:       "" IF_DESKTOP("[-b/k/m/g]")
  24 //usage:#define free_full_usage "\n\n"
  25 //usage:       "Display the amount of free and used system memory"
  26 //usage:
  27 //usage:#define free_example_usage
  28 //usage:       "$ free\n"
  29 //usage:       "              total         used         free       shared      buffers\n"
  30 //usage:       "  Mem:       257628       248724         8904        59644        93124\n"
  31 //usage:       " Swap:       128516         8404       120112\n"
  32 //usage:       "Total:       386144       257128       129016\n"
  33
  34 #include "libbb.h"
  35 #include "common_bufsiz.h"
  36 #ifdef __linux__
  37 # include <sys/sysinfo.h>
  38 #endif
  39
  40 struct globals {
  41         unsigned mem_unit;
  42 #if ENABLE_DESKTOP
  43         unsigned unit_steps;
  44 # define G_unit_steps G.unit_steps
  45 #else
  46 # define G_unit_steps 10
  47 #endif
  48 } FIX_ALIASING;
  49 #define G (*(struct globals*)bb_common_bufsiz1)
  50 #define INIT_G() do { setup_common_bufsiz(); } while (0)
  51
  52
  53 static unsigned long long scale(unsigned long d)
  54 {
  55         return ((unsigned long long)d * G.mem_unit) >> G_unit_steps;
  56 }
  57
  58 static unsigned long parse_cached_kb(void)
  59 {
  60         char buf[60]; /* actual lines we expect are ~30 chars or less */
  61         FILE *fp;
  62         unsigned long cached = 0;
  63
  64         fp = xfopen_for_read("/proc/meminfo");
  65         while (fgets(buf, sizeof(buf), fp) != NULL) {
  66                 if (sscanf(buf, "Cached: %lu %*s\n", &cached) == 1)
  67                         break;
  68         }
  69         if (ENABLE_FEATURE_CLEAN_UP)
  70                 fclose(fp);
  71
  72         return cached;
  73 }
  74
  75 int free_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  76 int free_main(int argc UNUSED_PARAM, char **argv IF_NOT_DESKTOP(UNUSED_PARAM))
  77 {
  78         struct sysinfo info;
  79         unsigned long long cached;
  80
  81         INIT_G();
  82
  83 #if ENABLE_DESKTOP
  84         G.unit_steps = 10;
  85         if (argv[1] && argv[1][0] == '-') {
  86                 switch (argv[1][1]) {
  87                 case 'b':
  88                         G.unit_steps = 0;
  89                         break;
  90                 case 'k': /* 2^10 */
  91                         /* G.unit_steps = 10; - already is */
  92                         break;
  93                 case 'm': /* 2^(2*10) */
  94                         G.unit_steps = 20;
  95                         break;
  96                 case 'g': /* 2^(3*10) */
  97                         G.unit_steps = 30;
  98                         break;
  99                 default:
 100                         bb_show_usage();
 101                 }
 102         }
 103 #endif
 104         printf("       %11s%11s%11s%11s%11s%11s\n"
 105         "Mem:   ",
 106                 "total",
 107                 "used",
 108                 "free",
 109                 "shared", "buffers", "cached" /* swap and total don't have these columns */
 110         );
 111
 112         sysinfo(&info);
 113         /* Kernels prior to 2.4.x will return info.mem_unit==0, so cope... */
 114         G.mem_unit = (info.mem_unit ? info.mem_unit : 1);
 115         /* Extract cached from /proc/meminfo and convert to mem_units */
 116         cached = ((unsigned long long) parse_cached_kb() * 1024) / G.mem_unit;
 117
 118 #define FIELDS_6 "%11llu%11llu%11llu%11llu%11llu%11llu\n"
 119 #define FIELDS_3 (FIELDS_6 + 3*6)
 120 #define FIELDS_2 (FIELDS_6 + 4*6)
 121
 122         printf(FIELDS_6,
 123                 scale(info.totalram),                //total
 124                 scale(info.totalram - info.freeram), //used
 125                 scale(info.freeram),                 //free
 126                 scale(info.sharedram),               //shared
 127                 scale(info.bufferram),               //buffers
 128                 scale(cached)                        //cached
 129         );
 130         /* Show alternate, more meaningful busy/free numbers by counting
 131          * buffer cache as free memory. */
 132         printf("-/+ buffers/cache:");
 133         cached += info.freeram;
 134         cached += info.bufferram;
 135         printf(FIELDS_2,
 136                 scale(info.totalram - cached), //used
 137                 scale(cached)                  //free
 138         );
 139 #if BB_MMU
 140         printf("Swap:  ");
 141         printf(FIELDS_3,
 142                 scale(info.totalswap),                 //total
 143                 scale(info.totalswap - info.freeswap), //used
 144                 scale(info.freeswap)                   //free
 145         );
 146 #endif
 147         return EXIT_SUCCESS;
 148 }