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/* vi: set sw=4 ts=4: */
/*
* Mini free implementation for busybox
*
* Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
*
* Licensed under GPLv2, see file LICENSE in this source tree.
*/
//config:config FREE
//config: bool "free (3.1 kb)"
//config: default y
//config: help
//config: free displays the total amount of free and used physical and swap
//config: memory in the system, as well as the buffers used by the kernel.
//config: The shared memory column should be ignored; it is obsolete.
//applet:IF_FREE(APPLET_NOFORK(free, free, BB_DIR_USR_BIN, BB_SUID_DROP, free))
//kbuild:lib-$(CONFIG_FREE) += free.o
//usage:#define free_trivial_usage
//usage: "" IF_DESKTOP("[-b/k/m/g]")
//usage:#define free_full_usage "\n\n"
//usage: "Display the amount of free and used system memory"
//usage:
//usage:#define free_example_usage
//usage: "$ 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"
#ifdef __linux__
# include <sys/sysinfo.h>
#endif
struct globals {
unsigned mem_unit;
#if ENABLE_DESKTOP
uint8_t unit_steps;
# define G_unit_steps g->unit_steps
#else
# define G_unit_steps 10
#endif
unsigned long cached_kb, available_kb, reclaimable_kb;
};
/* Because of NOFORK, "globals" are not in global data */
static unsigned long long scale(struct globals *g, unsigned long d)
{
return ((unsigned long long)d * g->mem_unit) >> G_unit_steps;
}
/* NOINLINE reduces main() stack usage, which makes code smaller (on x86 at least) */
static NOINLINE unsigned int parse_meminfo(struct globals *g)
{
char buf[60]; /* actual lines we expect are ~30 chars or less */
FILE *fp;
int seen_cached_and_available_and_reclaimable;
fp = xfopen_for_read("/proc/meminfo");
g->cached_kb = g->available_kb = g->reclaimable_kb = 0;
seen_cached_and_available_and_reclaimable = 3;
while (fgets(buf, sizeof(buf), fp)) {
if (sscanf(buf, "Cached: %lu %*s\n", &g->cached_kb) == 1)
if (--seen_cached_and_available_and_reclaimable == 0)
break;
if (sscanf(buf, "MemAvailable: %lu %*s\n", &g->available_kb) == 1)
if (--seen_cached_and_available_and_reclaimable == 0)
break;
if (sscanf(buf, "SReclaimable: %lu %*s\n", &g->reclaimable_kb) == 1)
if (--seen_cached_and_available_and_reclaimable == 0)
break;
}
/* Have to close because of NOFORK */
fclose(fp);
return seen_cached_and_available_and_reclaimable == 0;
}
int free_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int free_main(int argc UNUSED_PARAM, char **argv IF_NOT_DESKTOP(UNUSED_PARAM))
{
struct globals G;
struct sysinfo info;
unsigned long long cached, cached_plus_free, available;
int seen_available;
#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': /* 2^20 */
G.unit_steps = 20;
break;
case 'g': /* 2^30 */
G.unit_steps = 30;
break;
default:
bb_show_usage();
}
}
#endif
printf(" %12s%12s%12s%12s%12s%12s\n"
"Mem: ",
"total",
"used",
"free",
"shared", "buff/cache", "available" /* swap and total don't have these columns */
);
sysinfo(&info);
/* Extract cached and memavailable from /proc/meminfo and convert to mem_units */
seen_available = parse_meminfo(&G);
G.mem_unit = (info.mem_unit ? info.mem_unit : 1); /* kernels < 2.4.x return mem_unit==0, so cope */
available = ((unsigned long long) G.available_kb * 1024) / G.mem_unit;
cached = ((unsigned long long) G.cached_kb * 1024) / G.mem_unit;
cached += info.bufferram;
cached += ((unsigned long long) G.reclaimable_kb * 1024) / G.mem_unit;
cached_plus_free = cached + info.freeram;
/* In case (long long * G.mem_unit) can overflow, this can be used to reduce the chances */
#if 0 //ENABLE_DESKTOP
while (!(G.mem_unit & 1) && G.unit_steps != 0) {
G.mem_unit >>= 1;
G.unit_steps--;
//bb_error_msg("mem_unit:%d unit_steps:%d", G.mem_unit, G.unit_steps);
}
#endif
#define FIELDS_6 "%12llu %11llu %11llu %11llu %11llu %11llu\n"
#define FIELDS_3 (FIELDS_6 + 6 + 7 + 7)
#define FIELDS_2 (FIELDS_6 + 6 + 7 + 7 + 7)
printf(FIELDS_6,
scale(&G, info.totalram), //total
scale(&G, info.totalram - cached_plus_free), //used
scale(&G, info.freeram), //free
scale(&G, info.sharedram), //shared
scale(&G, cached), //buff/cache
scale(&G, available) //available
);
/* On kernels < 3.14, MemAvailable is not provided.
* Show alternate, more meaningful busy/free numbers by counting
* buffer cache as free memory. */
if (!seen_available) {
printf("-/+ buffers/cache: ");
printf(FIELDS_2,
scale(&G, info.totalram - cached_plus_free), //used
scale(&G, cached_plus_free) //free
);
}
#if BB_MMU
printf("Swap: ");
printf(FIELDS_3,
scale(&G, info.totalswap), //total
scale(&G, info.totalswap - info.freeswap), //used
scale(&G, info.freeswap) //free
);
#endif
return EXIT_SUCCESS;
}
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