aboutsummaryrefslogtreecommitdiff
path: root/procps/nmeter.c
blob: f08938654852ccd3af48a1bd2bd6d10599e1aa00 (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
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
/*
 * Licensed under GPLv2, see file LICENSE in this source tree.
 *
 * Based on nanotop.c from floppyfw project
 *
 * Contact me: vda.linux@googlemail.com
 */
//config:config NMETER
//config:	bool "nmeter (11 kb)"
//config:	default y
//config:	help
//config:	Prints selected system stats continuously, one line per update.

//applet:IF_NMETER(APPLET(nmeter, BB_DIR_USR_BIN, BB_SUID_DROP))

//kbuild:lib-$(CONFIG_NMETER) += nmeter.o

//usage:#define nmeter_trivial_usage
//usage:       "[-d MSEC] FORMAT_STRING"
//usage:#define nmeter_full_usage "\n\n"
//usage:       "Monitor system in real time"
//usage:     "\n"
//usage:     "\n -d MSEC	Milliseconds between updates, default:1000, none:-1"
//usage:     "\n"
//usage:     "\nFormat specifiers:"
//usage:     "\n %Nc or %[cN]	CPU. N - bar size (default 10)"
//usage:     "\n		(displays: S:system U:user N:niced D:iowait I:irq i:softirq)"
//usage:     "\n %[nINTERFACE]	Network INTERFACE"
//usage:     "\n %m		Allocated memory"
//usage:     "\n %[mf]		Free memory"
//usage:     "\n %[mt]		Total memory"
//usage:     "\n %s		Allocated swap"
//usage:     "\n %f		Number of used file descriptors"
//usage:     "\n %Ni		Total/specific IRQ rate"
//usage:     "\n %x		Context switch rate"
//usage:     "\n %p		Forks"
//usage:     "\n %[pn]		# of processes"
//usage:     "\n %b		Block io"
//usage:     "\n %Nt		Time (with N decimal points)"
//usage:     "\n %NT		Zero-based timestamp (with N decimal points)"
//usage:     "\n %r		Print <cr> instead of <lf> at EOL"

//TODO:
// simplify code
// /proc/locks
// /proc/stat:
// disk_io: (3,0):(22272,17897,410702,4375,54750)
// btime 1059401962
//TODO: use sysinfo libc call/syscall, if appropriate
// (faster than open/read/close):
// sysinfo({uptime=15017, loads=[5728, 15040, 16480]
//  totalram=2107416576, freeram=211525632, sharedram=0, bufferram=157204480}
//  totalswap=134209536, freeswap=134209536, procs=157})

#include "libbb.h"
#include "common_bufsiz.h"

typedef unsigned long long ullong;

enum {  /* Preferably use powers of 2 */
	PROC_MIN_FILE_SIZE = 256,
	PROC_MAX_FILE_SIZE = 16 * 1024,
};

typedef struct proc_file {
	char *file;
	int file_sz;
	smallint last_gen;
} proc_file;

static const char *const proc_name[] = {
	"stat",		// Must match the order of proc_file's!
	"loadavg",
	"net/dev",
	"meminfo",
	"diskstats",
	"sys/fs/file-nr"
};

struct globals {
	// Sample generation flip-flop
	smallint gen;
	// Linux 2.6? (otherwise assumes 2.4)
	smallint is26;
	// 1 if sample delay is not an integer fraction of a second
	smallint need_seconds;
	char final_char;
	char *cur_outbuf;
	int delta;
	unsigned deltanz;
	struct timeval tv;
	struct timeval start;
#define first_proc_file proc_stat
	proc_file proc_stat;	// Must match the order of proc_name's!
	proc_file proc_loadavg;
	proc_file proc_net_dev;
	proc_file proc_meminfo;
	proc_file proc_diskstats;
	proc_file proc_sys_fs_filenr;
};
#define G (*ptr_to_globals)
#define gen                (G.gen               )
#define is26               (G.is26              )
#define need_seconds       (G.need_seconds      )
#define cur_outbuf         (G.cur_outbuf        )
#define proc_stat          (G.proc_stat         )
#define proc_loadavg       (G.proc_loadavg      )
#define proc_net_dev       (G.proc_net_dev      )
#define proc_meminfo       (G.proc_meminfo      )
#define proc_diskstats     (G.proc_diskstats    )
#define proc_sys_fs_filenr (G.proc_sys_fs_filenr)
#define outbuf bb_common_bufsiz1
#define INIT_G() do { \
	setup_common_bufsiz(); \
	SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \
	cur_outbuf = outbuf; \
	G.final_char = '\n'; \
	G.deltanz = G.delta = 1000000; \
} while (0)

static inline void reset_outbuf(void)
{
	cur_outbuf = outbuf;
}

static void print_outbuf(void)
{
	int sz = cur_outbuf - outbuf;
	if (sz > 0) {
		xwrite(STDOUT_FILENO, outbuf, sz);
		cur_outbuf = outbuf;
	}
}

static void put(const char *s)
{
	char *p = cur_outbuf;
	int sz = outbuf + COMMON_BUFSIZE - p;
	while (*s && --sz >= 0)
		*p++ = *s++;
	cur_outbuf = p;
}

static void put_c(char c)
{
	if (cur_outbuf < outbuf + COMMON_BUFSIZE)
		*cur_outbuf++ = c;
}

static void put_question_marks(int count)
{
	while (count--)
		put_c('?');
}

static void readfile_z(proc_file *pf, const char* fname)
{
// open_read_close() will do two reads in order to be sure we are at EOF,
// and we don't need/want that.
	int fd;
	int sz, rdsz;
	char *buf;

	sz = pf->file_sz;
	buf = pf->file;
	if (!buf) {
		buf = xmalloc(PROC_MIN_FILE_SIZE);
		sz = PROC_MIN_FILE_SIZE;
	}
 again:
	fd = xopen(fname, O_RDONLY);
	buf[0] = '\0';
	rdsz = read(fd, buf, sz-1);
	close(fd);
	if (rdsz > 0) {
		if (rdsz == sz-1 && sz < PROC_MAX_FILE_SIZE) {
			sz *= 2;
			buf = xrealloc(buf, sz);
			goto again;
		}
		buf[rdsz] = '\0';
	}
	pf->file_sz = sz;
	pf->file = buf;
}

static const char* get_file(proc_file *pf)
{
	if (pf->last_gen != gen) {
		pf->last_gen = gen;
		readfile_z(pf, proc_name[pf - &first_proc_file]);
	}
	return pf->file;
}

static ullong read_after_slash(const char *p)
{
	p = strchr(p, '/');
	if (!p) return 0;
	return strtoull(p+1, NULL, 10);
}

enum conv_type {
	conv_decimal = 0,
	conv_slash = 1
};

// Reads decimal values from line. Values start after key, for example:
// "cpu  649369 0 341297 4336769..." - key is "cpu" here.
// Values are stored in vec[].
// posbits is a bit lit of positions we are interested in.
// for example: 00100110 - we want 1st, 2nd and 5th value.
// posbits.bit0 encodes conversion type.
static int rdval(const char* p, const char* key, ullong *vec, long posbits)
{
	unsigned curpos;

	p = strstr(p, key);
	if (!p) return 1;

	p += strlen(key);
	curpos = 1 << 1;
	while (1) {
		while (*p == ' ' || *p == '\t') p++;
		if (*p == '\n' || *p == '\0') break;

		if (curpos & posbits) { // read this value
			*vec++ = (posbits & 1) == conv_decimal ?
				strtoull(p, NULL, 10) :
				read_after_slash(p);
			posbits -= curpos;
			if (posbits <= 1)
				return 0;
		}
		while (*p > ' ') // skip over the value
			p++;
		curpos <<= 1;
	}
	return 0;
}

// Parses files with lines like "... ... ... 3/148 ...."
static int rdval_loadavg(const char* p, ullong *vec, long posbits)
{
	int result;
	result = rdval(p, "", vec, posbits | conv_slash);
	return result;
}

// Parses /proc/diskstats
//   1  2 3   4     5     6(rd)  7      8     9     10(wr) 11     12 13     14
//   3  0 hda 51292 14441 841783 926052 25717 79650 843256 3029804 0 148459 3956933
//   3  1 hda1 0 0 0 0 <- ignore if only 4 fields
// Linux 3.0 (maybe earlier) started printing full stats for hda1 too.
// Had to add code which skips such devices.
static int rdval_diskstats(const char* p, ullong *vec)
{
	char devname[32];
	unsigned devname_len = 0;
	int value_idx = 0;

	vec[0] = 0;
	vec[1] = 0;
	while (1) {
		value_idx++;
		while (*p == ' ' || *p == '\t')
			p++;
		if (*p == '\0')
			break;
		if (*p == '\n') {
			value_idx = 0;
			p++;
			continue;
		}
		if (value_idx == 3) {
			char *end = strchrnul(p, ' ');
			/* If this a hda1-like device (same prefix as last one + digit)? */
			if (devname_len && strncmp(devname, p, devname_len) == 0 && isdigit(p[devname_len])) {
				p = end;
				goto skip_line; /* skip entire line */
			}
			/* It is not. Remember the name for future checks */
			devname_len = end - p;
			if (devname_len > sizeof(devname)-1)
				devname_len = sizeof(devname)-1;
			strncpy(devname, p, devname_len);
			/* devname[devname_len] = '\0'; - not really needed */
			p = end;
		} else
		if (value_idx == 6) {
			// TODO: *sectorsize (don't know how to find out sectorsize)
			vec[0] += strtoull(p, NULL, 10);
		} else
		if (value_idx == 10) {
			// TODO: *sectorsize (don't know how to find out sectorsize)
			vec[1] += strtoull(p, NULL, 10);
 skip_line:
			while (*p != '\n' && *p != '\0')
				p++;
			continue;
		}
		while ((unsigned char)(*p) > ' ') // skip over value
			p++;
	}
	return 0;
}

static void scale(ullong ul)
{
	char buf[5];

	/* see http://en.wikipedia.org/wiki/Tera */
	smart_ulltoa4(ul, buf, " kmgtpezy")[0] = '\0';
	put(buf);
}

#define S_STAT(a) \
typedef struct a { \
	struct s_stat *next; \
	void (*collect)(struct a *s) FAST_FUNC; \
	const char *label;
#define S_STAT_END(a) } a;

S_STAT(s_stat)
S_STAT_END(s_stat)

static void FAST_FUNC collect_literal(s_stat *s UNUSED_PARAM)
{
}

static s_stat* init_literal(void)
{
	s_stat *s = xzalloc(sizeof(*s));
	s->collect = collect_literal;
	return (s_stat*)s;
}

static s_stat* init_cr(const char *param UNUSED_PARAM)
{
	G.final_char = '\r';
	return NULL;
}

//     user nice system idle  iowait irq  softirq (last 3 only in 2.6)
//cpu  649369 0 341297 4336769 11640 7122 1183
//cpuN 649369 0 341297 4336769 11640 7122 1183
enum { CPU_FIELDCNT = 7 };
S_STAT(cpu_stat)
	ullong old[CPU_FIELDCNT];
	unsigned bar_sz;
	char bar[1];
S_STAT_END(cpu_stat)

static void FAST_FUNC collect_cpu(cpu_stat *s)
{
	ullong data[CPU_FIELDCNT] = { 0, 0, 0, 0, 0, 0, 0 };
	unsigned frac[CPU_FIELDCNT] = { 0, 0, 0, 0, 0, 0, 0 };
	ullong all = 0;
	unsigned norm_all = 0;
	unsigned bar_sz = s->bar_sz;
	char *bar = s->bar;
	int i;

	if (rdval(get_file(&proc_stat), "cpu ", data, 0
	    | (1 << 1)
	    | (1 << 2)
	    | (1 << 3)
	    | (1 << 4)
	    | (1 << 5)
	    | (1 << 6)
	    | (1 << 7))
	) {
		put_question_marks(bar_sz);
		return;
	}

	for (i = 0; i < CPU_FIELDCNT; i++) {
		ullong old = s->old[i];
		if (data[i] < old) old = data[i];		//sanitize
		s->old[i] = data[i];
		all += (data[i] -= old);
	}

	if (all) {
		for (i = 0; i < CPU_FIELDCNT; i++) {
			ullong t = bar_sz * data[i];
			norm_all += data[i] = t / all;
			frac[i] = t % all;
		}

		while (norm_all < bar_sz) {
			unsigned max = frac[0];
			int pos = 0;
			for (i = 1; i < CPU_FIELDCNT; i++) {
				if (frac[i] > max) max = frac[i], pos = i;
			}
			frac[pos] = 0;	//avoid bumping up same value twice
			data[pos]++;
			norm_all++;
		}

		memset(bar, '.', bar_sz);
		memset(bar, 'S', data[2]); bar += data[2]; //sys
		memset(bar, 'U', data[0]); bar += data[0]; //usr
		memset(bar, 'N', data[1]); bar += data[1]; //nice
		memset(bar, 'D', data[4]); bar += data[4]; //iowait
		memset(bar, 'I', data[5]); bar += data[5]; //irq
		memset(bar, 'i', data[6]); bar += data[6]; //softirq
	} else {
		memset(bar, '?', bar_sz);
	}
	put(s->bar);
}

static s_stat* init_cpu(const char *param)
{
	int sz;
	cpu_stat *s;
	sz = param[0] ? strtoul(param, NULL, 0) : 10;
	if (sz <= 0) sz = 1;
	if (sz > 1000) sz = 1000;
	s = xzalloc(sizeof(*s) + sz);
	/*s->bar[sz] = '\0'; - xzalloc did it */
	s->bar_sz = sz;
	s->collect = collect_cpu;
	return (s_stat*)s;
}

S_STAT(int_stat)
	ullong old;
	int no;
S_STAT_END(int_stat)

static void FAST_FUNC collect_int(int_stat *s)
{
	ullong data[1];
	ullong old;

	if (rdval(get_file(&proc_stat), "intr", data, 1 << s->no)) {
		put_question_marks(4);
		return;
	}

	old = s->old;
	if (data[0] < old) old = data[0];		//sanitize
	s->old = data[0];
	scale(data[0] - old);
}

static s_stat* init_int(const char *param)
{
	int_stat *s = xzalloc(sizeof(*s));
	s->collect = collect_int;
	if (param[0] == '\0') {
		s->no = 1;
	} else {
		int n = xatoi_positive(param);
		s->no = n + 2;
	}
	return (s_stat*)s;
}

S_STAT(ctx_stat)
	ullong old;
S_STAT_END(ctx_stat)

static void FAST_FUNC collect_ctx(ctx_stat *s)
{
	ullong data[1];
	ullong old;

	if (rdval(get_file(&proc_stat), "ctxt", data, 1 << 1)) {
		put_question_marks(4);
		return;
	}

	old = s->old;
	if (data[0] < old) old = data[0];		//sanitize
	s->old = data[0];
	scale(data[0] - old);
}

static s_stat* init_ctx(const char *param UNUSED_PARAM)
{
	ctx_stat *s = xzalloc(sizeof(*s));
	s->collect = collect_ctx;
	return (s_stat*)s;
}

S_STAT(blk_stat)
	const char* lookfor;
	ullong old[2];
S_STAT_END(blk_stat)

static void FAST_FUNC collect_blk(blk_stat *s)
{
	ullong data[2];
	int i;

	if (is26) {
		i = rdval_diskstats(get_file(&proc_diskstats), data);
	} else {
		i = rdval(get_file(&proc_stat), s->lookfor, data, 0
				| (1 << 1)
				| (1 << 2)
		);
		// Linux 2.4 reports bio in Kbytes, convert to sectors:
		data[0] *= 2;
		data[1] *= 2;
	}
	if (i) {
		put_question_marks(9);
		return;
	}

	for (i=0; i<2; i++) {
		ullong old = s->old[i];
		if (data[i] < old) old = data[i];		//sanitize
		s->old[i] = data[i];
		data[i] -= old;
	}
	scale(data[0]*512); // TODO: *sectorsize
	put_c(' ');
	scale(data[1]*512);
}

static s_stat* init_blk(const char *param UNUSED_PARAM)
{
	blk_stat *s = xzalloc(sizeof(*s));
	s->collect = collect_blk;
	s->lookfor = "page";
	return (s_stat*)s;
}

S_STAT(fork_stat)
	ullong old;
S_STAT_END(fork_stat)

static void FAST_FUNC collect_thread_nr(fork_stat *s UNUSED_PARAM)
{
	ullong data[1];

	if (rdval_loadavg(get_file(&proc_loadavg), data, 1 << 4)) {
		put_question_marks(4);
		return;
	}
	scale(data[0]);
}

static void FAST_FUNC collect_fork(fork_stat *s)
{
	ullong data[1];
	ullong old;

	if (rdval(get_file(&proc_stat), "processes", data, 1 << 1)) {
		put_question_marks(4);
		return;
	}

	old = s->old;
	if (data[0] < old) old = data[0];	//sanitize
	s->old = data[0];
	scale(data[0] - old);
}

static s_stat* init_fork(const char *param)
{
	fork_stat *s = xzalloc(sizeof(*s));
	if (*param == 'n') {
		s->collect = collect_thread_nr;
	} else {
		s->collect = collect_fork;
	}
	return (s_stat*)s;
}

S_STAT(if_stat)
	ullong old[4];
	const char *device;
	char *device_colon;
S_STAT_END(if_stat)

static void FAST_FUNC collect_if(if_stat *s)
{
	ullong data[4];
	int i;

	if (rdval(get_file(&proc_net_dev), s->device_colon, data, 0
	    | (1 << 1)
	    | (1 << 3)
	    | (1 << 9)
	    | (1 << 11))
	) {
		put_question_marks(10);
		return;
	}

	for (i=0; i<4; i++) {
		ullong old = s->old[i];
		if (data[i] < old) old = data[i];		//sanitize
		s->old[i] = data[i];
		data[i] -= old;
	}
	put_c(data[1] ? '*' : ' ');
	scale(data[0]);
	put_c(data[3] ? '*' : ' ');
	scale(data[2]);
}

static s_stat* init_if(const char *device)
{
	if_stat *s = xzalloc(sizeof(*s));

	if (!device || !device[0])
		bb_show_usage();
	s->collect = collect_if;

	s->device = device;
	s->device_colon = xasprintf("%s:", device);
	return (s_stat*)s;
}

S_STAT(mem_stat)
	char opt;
S_STAT_END(mem_stat)

// "Memory" value should not include any caches.
// IOW: neither "ls -laR /" nor heavy read/write activity
//      should affect it. We'd like to also include any
//      long-term allocated kernel-side mem, but it is hard
//      to figure out. For now, bufs, cached & slab are
//      counted as "free" memory
//2.6.16:
//MemTotal:       773280 kB
//MemFree:         25912 kB - genuinely free
//Buffers:        320672 kB - cache
//Cached:         146396 kB - cache
//SwapCached:          0 kB
//Active:         183064 kB
//Inactive:       356892 kB
//HighTotal:           0 kB
//HighFree:            0 kB
//LowTotal:       773280 kB
//LowFree:         25912 kB
//SwapTotal:      131064 kB
//SwapFree:       131064 kB
//Dirty:              48 kB
//Writeback:           0 kB
//Mapped:          96620 kB
//Slab:           200668 kB - takes 7 Mb on my box fresh after boot,
//                            but includes dentries and inodes
//                            (== can take arbitrary amount of mem)
//CommitLimit:    517704 kB
//Committed_AS:   236776 kB
//PageTables:       1248 kB
//VmallocTotal:   516052 kB
//VmallocUsed:      3852 kB
//VmallocChunk:   512096 kB
//HugePages_Total:     0
//HugePages_Free:      0
//Hugepagesize:     4096 kB
static void FAST_FUNC collect_mem(mem_stat *s)
{
	ullong m_total = 0;
	ullong m_free = 0;
	ullong m_bufs = 0;
	ullong m_cached = 0;
	ullong m_slab = 0;

	if (rdval(get_file(&proc_meminfo), "MemTotal:", &m_total, 1 << 1)) {
		put_question_marks(4);
		return;
	}
	if (s->opt == 't') {
		scale(m_total << 10);
		return;
	}

	if (rdval(proc_meminfo.file, "MemFree:", &m_free  , 1 << 1)
	 || rdval(proc_meminfo.file, "Buffers:", &m_bufs  , 1 << 1)
	 || rdval(proc_meminfo.file, "Cached:",  &m_cached, 1 << 1)
	 || rdval(proc_meminfo.file, "Slab:",    &m_slab  , 1 << 1)
	) {
		put_question_marks(4);
		return;
	}

	m_free += m_bufs + m_cached + m_slab;
	switch (s->opt) {
	case 'f':
		scale(m_free << 10); break;
	default:
		scale((m_total - m_free) << 10); break;
	}
}

static s_stat* init_mem(const char *param)
{
	mem_stat *s = xzalloc(sizeof(*s));
	s->collect = collect_mem;
	s->opt = param[0];
	return (s_stat*)s;
}

S_STAT(swp_stat)
S_STAT_END(swp_stat)

static void FAST_FUNC collect_swp(swp_stat *s UNUSED_PARAM)
{
	ullong s_total[1];
	ullong s_free[1];
	if (rdval(get_file(&proc_meminfo), "SwapTotal:", s_total, 1 << 1)
	 || rdval(proc_meminfo.file,       "SwapFree:" , s_free,  1 << 1)
	) {
		put_question_marks(4);
		return;
	}
	scale((s_total[0]-s_free[0]) << 10);
}

static s_stat* init_swp(const char *param UNUSED_PARAM)
{
	swp_stat *s = xzalloc(sizeof(*s));
	s->collect = collect_swp;
	return (s_stat*)s;
}

S_STAT(fd_stat)
S_STAT_END(fd_stat)

static void FAST_FUNC collect_fd(fd_stat *s UNUSED_PARAM)
{
	ullong data[2];

	if (rdval(get_file(&proc_sys_fs_filenr), "", data, 0
	    | (1 << 1)
	    | (1 << 2))
	) {
		put_question_marks(4);
		return;
	}

	scale(data[0] - data[1]);
}

static s_stat* init_fd(const char *param UNUSED_PARAM)
{
	fd_stat *s = xzalloc(sizeof(*s));
	s->collect = collect_fd;
	return (s_stat*)s;
}

S_STAT(time_stat)
	unsigned prec;
	unsigned scale;
S_STAT_END(time_stat)

static void FAST_FUNC collect_tv(time_stat *s, struct timeval *tv, int local)
{
	char buf[sizeof("12:34:56.123456")];
	struct tm* tm;
	unsigned us = tv->tv_usec + s->scale/2;
	time_t t = tv->tv_sec;

	if (us >= 1000000) {
		t++;
		us -= 1000000;
	}
	if (local)
		tm = localtime(&t);
	else
		tm = gmtime(&t);

	sprintf(buf, "%02u:%02u:%02u", tm->tm_hour, tm->tm_min, tm->tm_sec);
	if (s->prec)
		sprintf(buf+8, ".%0*u", s->prec, us / s->scale);
	put(buf);
}

static void FAST_FUNC collect_time(time_stat *s)
{
	collect_tv(s, &G.tv, /*local:*/ 1);
}

static void FAST_FUNC collect_monotonic(time_stat *s)
{
	struct timeval tv_mono;

	tv_mono.tv_sec = G.tv.tv_sec - G.start.tv_sec;
#if 0 /* Do we want this? */
	if (tv_mono.tv_sec < 0) {
		/* Time went backwards, reset start time to "now" */
		tv_mono.tv_sec = 0;
		G.start = G.tv;
	}
#endif
	tv_mono.tv_usec = G.tv.tv_usec - G.start.tv_usec;
	if ((int32_t)tv_mono.tv_usec < 0) {
		tv_mono.tv_usec += 1000000;
		tv_mono.tv_sec--;
	}
	collect_tv(s, &tv_mono, /*local:*/ 0);
}

static s_stat* init_time(const char *param)
{
	int prec;
	time_stat *s = xzalloc(sizeof(*s));

	s->collect = collect_time;
	prec = param[0] - '0';
	if (prec < 0) prec = 0;
	else if (prec > 6) prec = 6;
	s->prec = prec;
	s->scale = 1;
	while (prec++ < 6)
		s->scale *= 10;
	return (s_stat*)s;
}

static s_stat* init_monotonic(const char *param)
{
	time_stat *s = (void*)init_time(param);
	s->collect = collect_monotonic;
	return (s_stat*)s;
}

static void FAST_FUNC collect_info(s_stat *s)
{
	gen ^= 1;
	while (s) {
		put(s->label);
		s->collect(s);
		s = s->next;
	}
}

typedef s_stat* init_func(const char *param);

static const char options[] ALIGN1 = "ncmsfixptTbr";
static init_func *const init_functions[] ALIGN_PTR = {
	init_if,
	init_cpu,
	init_mem,
	init_swp,
	init_fd,
	init_int,
	init_ctx,
	init_fork,
	init_time,
	init_monotonic,
	init_blk,
	init_cr
};

int nmeter_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int nmeter_main(int argc UNUSED_PARAM, char **argv)
{
	char buf[32];
	s_stat *first = NULL;
	s_stat *last = NULL;
	s_stat *s;
	char *opt_d;
	char *cur, *prev;

	INIT_G();

	xchdir("/proc");

	if (open_read_close("version", buf, sizeof(buf)-1) > 0) {
		buf[sizeof(buf)-1] = '\0';
		is26 = (strstr(buf, " 2.4.") == NULL);
	}

	if (getopt32(argv, "d:", &opt_d)) {
		G.delta = xatoi(opt_d) * 1000;
		G.deltanz = G.delta > 0 ? G.delta : 1;
		need_seconds = (1000000 % G.deltanz) != 0;
	}
	argv += optind;

	if (!argv[0])
		bb_show_usage();

	// Can use argv[0] directly, but this will mess up
	// parameters as seen by e.g. ps. Making a copy...
	cur = xstrdup(argv[0]);
	while (1) {
		char *param, *p;
		prev = cur;
 again:
		cur = strchr(cur, '%');
		if (!cur)
			break;
		if (cur[1] == '%') {	// %%
			overlapping_strcpy(cur, cur + 1);
			cur++;
			goto again;
		}
		*cur++ = '\0';		// overwrite %
		if (cur[0] == '[') {
			// format: %[foptstring]
			cur++;
			p = strchr(options, cur[0]);
			param = cur+1;
			while (cur[0] != ']') {
				if (!cur[0])
					bb_show_usage();
				cur++;
			}
			*cur++ = '\0';	// overwrite [
		} else {
			// format: %NNNNNNf
			param = cur;
			while (cur[0] >= '0' && cur[0] <= '9')
				cur++;
			if (!cur[0])
				bb_show_usage();
			p = strchr(options, cur[0]);
			*cur++ = '\0';	// overwrite format char
		}
		if (!p)
			bb_show_usage();
		s = init_functions[p-options](param);
		if (s) {
			s->label = prev;
			/*s->next = NULL; - all initXXX funcs use xzalloc */
			if (!first)
				first = s;
			else
				last->next = s;
			last = s;
		} else {
			// %r option. remove it from string
			overlapping_strcpy(prev + strlen(prev), cur);
			cur = prev;
		}
	}
	if (prev[0]) {
		s = init_literal();
		s->label = prev;
		/*s->next = NULL; - all initXXX funcs use xzalloc */
		if (!first)
			first = s;
		else
			last->next = s;
		last = s;
	}

	// Generate first samples but do not print them, they're bogus
	collect_info(first);
	reset_outbuf();

	if (G.delta >= 0) {
		xgettimeofday(&G.tv);
		usleep(G.delta > 1000000 ? 1000000 : G.delta - G.tv.tv_usec % G.deltanz);
	}

	xgettimeofday(&G.start);
	G.tv = G.start;
	while (1) {
		collect_info(first);
		put_c(G.final_char);
		print_outbuf();

		// Negative delta -> no usleep at all
		// This will hog the CPU but you can have REALLY GOOD
		// time resolution ;)
		// TODO: detect and avoid useless updates
		// (like: nothing happens except time)
		if (G.delta >= 0) {
			int rem;
			// can be commented out, will sacrifice sleep time precision a bit
			xgettimeofday(&G.tv);
			if (need_seconds)
				rem = G.delta - ((ullong)G.tv.tv_sec*1000000 + G.tv.tv_usec) % G.deltanz;
			else
				rem = G.delta - (unsigned)G.tv.tv_usec % G.deltanz;
			// Sometimes kernel wakes us up just a tiny bit earlier than asked
			// Do not go to very short sleep in this case
			if (rem < (unsigned)G.delta / 128) {
				rem += G.delta;
			}
			usleep(rem);
		}
		xgettimeofday(&G.tv);
	}

	/*return 0;*/
}