summaryrefslogtreecommitdiff
path: root/procps/free.c
blob: 9fde64b64b714e7d0c2d95033beaa0e51a9bf672 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
/* 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 { } 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;
}