source: MondoRescue/branches/3.3/mindi-busybox/procps/free.c@ 3865

/* 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.
 */

/* 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"
#include "common_bufsiz.h"
#ifdef __linux__
# include <sys/sysinfo.h>
#endif

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 { setup_common_bufsiz(); } while (0)


static unsigned long long scale(unsigned long d)
{
    return ((unsigned long long)d * G.mem_unit) >> G_unit_steps;
}

static unsigned long parse_cached_kb(void)
{
    char buf[60]; /* actual lines we expect are ~30 chars or less */
    FILE *fp;
    unsigned long cached = 0;

    fp = xfopen_for_read("/proc/meminfo");
    while (fgets(buf, sizeof(buf), fp) != NULL) {
        if (sscanf(buf, "Cached: %lu %*s\n", &cached) == 1)
            break;
    }
    if (ENABLE_FEATURE_CLEAN_UP)
        fclose(fp);

    return cached;
}

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 sysinfo info;
    unsigned long long cached;

    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
    printf("       %11s%11s%11s%11s%11s%11s\n"
    "Mem:   ",
        "total",
        "used",
        "free",
        "shared", "buffers", "cached" /* swap and total don't have these columns */
    );

    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);
    /* Extract cached from /proc/meminfo and convert to mem_units */
    cached = ((unsigned long long) parse_cached_kb() * 1024) / G.mem_unit;

#define FIELDS_6 "%11llu%11llu%11llu%11llu%11llu%11llu\n"
#define FIELDS_3 (FIELDS_6 + 3*6)
#define FIELDS_2 (FIELDS_6 + 4*6)

    printf(FIELDS_6,
        scale(info.totalram),                //total
        scale(info.totalram - info.freeram), //used
        scale(info.freeram),                 //free
        scale(info.sharedram),               //shared
        scale(info.bufferram),               //buffers
        scale(cached)                        //cached
    );
    /* Show alternate, more meaningful busy/free numbers by counting
     * buffer cache as free memory. */
    printf("-/+ buffers/cache:");
    cached += info.freeram;
    cached += info.bufferram;
    printf(FIELDS_2,
        scale(info.totalram - cached), //used
        scale(cached)                  //free
    );
#if BB_MMU
    printf("Swap:  ");
    printf(FIELDS_3,
        scale(info.totalswap),                 //total
        scale(info.totalswap - info.freeswap), //used
        scale(info.freeswap)                   //free
    );
#endif
    return EXIT_SUCCESS;
}