busybox/procps/free.c

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/* vi: set sw=4 ts=4: */
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/*
* Mini free implementation for busybox
*
* Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
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*
* Licensed under GPLv2, see file LICENSE in this source tree.
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*/
/* getopt not needed */
//usage:#define free_trivial_usage
//usage: "" IF_DESKTOP("[-b/k/m/g]")
//usage:#define free_full_usage "\n\n"
//usage: "Display the amount of free and used system memory"
//usage:
//usage:#define free_example_usage
//usage: "$ free\n"
//usage: " total used free shared buffers\n"
//usage: " Mem: 257628 248724 8904 59644 93124\n"
//usage: " Swap: 128516 8404 120112\n"
//usage: "Total: 386144 257128 129016\n"
#include "libbb.h"
struct globals {
unsigned mem_unit;
#if ENABLE_DESKTOP
unsigned unit_steps;
# define G_unit_steps G.unit_steps
#else
# define G_unit_steps 10
#endif
} FIX_ALIASING;
#define G (*(struct globals*)&bb_common_bufsiz1)
#define INIT_G() do { } while (0)
static unsigned long long scale(unsigned long d)
{
return ((unsigned long long)d * G.mem_unit) >> G_unit_steps;
}
int free_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int free_main(int argc UNUSED_PARAM, char **argv IF_NOT_DESKTOP(UNUSED_PARAM))
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{
struct sysinfo info;
INIT_G();
#if ENABLE_DESKTOP
G.unit_steps = 10;
if (argv[1] && argv[1][0] == '-') {
switch (argv[1][1]) {
case 'b':
G.unit_steps = 0;
break;
case 'k': /* 2^10 */
/* G.unit_steps = 10; - already is */
break;
case 'm': /* 2^(2*10) */
G.unit_steps = 20;
break;
case 'g': /* 2^(3*10) */
G.unit_steps = 30;
break;
default:
bb_show_usage();
}
}
#endif
sysinfo(&info);
/* Kernels prior to 2.4.x will return info.mem_unit==0, so cope... */
G.mem_unit = (info.mem_unit ? info.mem_unit : 1);
printf(" %13s%13s%13s%13s%13s\n",
"total",
"used",
"free",
"shared", "buffers" /* swap and total don't have these columns */
/* procps version 3.2.8 also shows "cached" column, but
* sysinfo() does not provide this value, need to parse
* /proc/meminfo instead and get "Cached: NNN kB" from there.
*/
);
#define FIELDS_5 "%13llu%13llu%13llu%13llu%13llu\n"
#define FIELDS_3 (FIELDS_5 + 2*6)
#define FIELDS_2 (FIELDS_5 + 3*6)
printf("Mem: ");
printf(FIELDS_5,
scale(info.totalram),
scale(info.totalram - info.freeram),
scale(info.freeram),
scale(info.sharedram),
scale(info.bufferram)
);
/* Show alternate, more meaningful busy/free numbers by counting
* buffer cache as free memory (make it "-/+ buffers/cache"
* if/when we add support for "cached" column): */
printf("-/+ buffers: ");
printf(FIELDS_2,
scale(info.totalram - info.freeram - info.bufferram),
scale(info.freeram + info.bufferram)
);
#if BB_MMU
printf("Swap:");
printf(FIELDS_3,
scale(info.totalswap),
scale(info.totalswap - info.freeswap),
scale(info.freeswap)
);
#endif
return EXIT_SUCCESS;
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}