aboutsummaryrefslogtreecommitdiff
path: root/coreutils/dd.c
blob: 30249707421f1268148b3503f777ef2be18f88c1 (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
/* vi: set sw=4 ts=4: */
/*
 * Mini dd implementation for busybox
 *
 *
 * Copyright (C) 2000,2001  Matt Kraai
 *
 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
 */

//config:config DD
//config:	bool "dd"
//config:	default y
//config:	help
//config:	  dd copies a file (from standard input to standard output,
//config:	  by default) using specific input and output blocksizes,
//config:	  while optionally performing conversions on it.
//config:
//config:config FEATURE_DD_SIGNAL_HANDLING
//config:	bool "Enable signal handling for status reporting"
//config:	default y
//config:	depends on DD
//config:	help
//config:	  Sending a SIGUSR1 signal to a running `dd' process makes it
//config:	  print to standard error the number of records read and written
//config:	  so far, then to resume copying.
//config:
//config:	  $ dd if=/dev/zero of=/dev/null &
//config:	  $ pid=$!; kill -USR1 $pid; sleep 1; kill $pid
//config:	  10899206+0 records in
//config:	  10899206+0 records out
//config:
//config:config FEATURE_DD_THIRD_STATUS_LINE
//config:	bool "Enable the third status line upon signal"
//config:	default y
//config:	depends on DD && FEATURE_DD_SIGNAL_HANDLING
//config:	help
//config:	  Displays a coreutils-like third status line with transferred bytes,
//config:	  elapsed time and speed.
//config:
//config:config FEATURE_DD_IBS_OBS
//config:	bool "Enable ibs, obs and conv options"
//config:	default y
//config:	depends on DD
//config:	help
//config:	  Enables support for writing a certain number of bytes in and out,
//config:	  at a time, and performing conversions on the data stream.
//config:
//config:config FEATURE_DD_STATUS
//config:	bool "Enable status display options"
//config:	default y
//config:	depends on DD
//config:	help
//config:	  Enables support for status=noxfer/none option.

//usage:#define dd_trivial_usage
//usage:       "[if=FILE] [of=FILE] " IF_FEATURE_DD_IBS_OBS("[ibs=N] [obs=N] ") "[bs=N] [count=N] [skip=N]\n"
//usage:       "	[seek=N]" IF_FEATURE_DD_IBS_OBS(" [conv=notrunc|noerror|sync|fsync]")
//usage:#define dd_full_usage "\n\n"
//usage:       "Copy a file with converting and formatting\n"
//usage:     "\n	if=FILE		Read from FILE instead of stdin"
//usage:     "\n	of=FILE		Write to FILE instead of stdout"
//usage:     "\n	bs=N		Read and write N bytes at a time"
//usage:	IF_FEATURE_DD_IBS_OBS(
//usage:     "\n	ibs=N		Read N bytes at a time"
//usage:	)
//usage:	IF_FEATURE_DD_IBS_OBS(
//usage:     "\n	obs=N		Write N bytes at a time"
//usage:	)
//usage:     "\n	count=N		Copy only N input blocks"
//usage:     "\n	skip=N		Skip N input blocks"
//usage:     "\n	seek=N		Skip N output blocks"
//usage:	IF_FEATURE_DD_IBS_OBS(
//usage:     "\n	conv=notrunc	Don't truncate output file"
//usage:     "\n	conv=noerror	Continue after read errors"
//usage:     "\n	conv=sync	Pad blocks with zeros"
//usage:     "\n	conv=fsync	Physically write data out before finishing"
//usage:     "\n	conv=swab	Swap every pair of bytes"
//usage:	)
//usage:	IF_FEATURE_DD_STATUS(
//usage:     "\n	status=noxfer	Suppress rate output"
//usage:     "\n	status=none	Suppress all output"
//usage:	)
//usage:     "\n"
//usage:     "\nN may be suffixed by c (1), w (2), b (512), kB (1000), k (1024), MB, M, GB, G"
//usage:
//usage:#define dd_example_usage
//usage:       "$ dd if=/dev/zero of=/dev/ram1 bs=1M count=4\n"
//usage:       "4+0 records in\n"
//usage:       "4+0 records out\n"

#include "libbb.h"

/* This is a NOEXEC applet. Be very careful! */


enum {
	ifd = STDIN_FILENO,
	ofd = STDOUT_FILENO,
};

static const struct suffix_mult dd_suffixes[] = {
	{ "c", 1 },
	{ "w", 2 },
	{ "b", 512 },
	{ "kB", 1000 },
	{ "kD", 1000 },
	{ "k", 1024 },
	{ "K", 1024 },  /* compat with coreutils dd (it also accepts KB and KD, TODO?) */
	{ "MB", 1000000 },
	{ "MD", 1000000 },
	{ "M", 1024*1024 },
	{ "GB", 1000000000 },
	{ "GD", 1000000000 },
	{ "G", 1024*1024*1024 },
	/* "D" suffix for decimal is not in coreutils manpage, looks like it's deprecated */
	/* coreutils also understands TPEZY suffixes for tera- and so on, with B suffix for decimal */
	{ "", 0 }
};

struct globals {
	off_t out_full, out_part, in_full, in_part;
#if ENABLE_FEATURE_DD_THIRD_STATUS_LINE
	unsigned long long total_bytes;
	unsigned long long begin_time_us;
#endif
	int flags;
} FIX_ALIASING;
#define G (*(struct globals*)&bb_common_bufsiz1)
#define INIT_G() do { \
	/* we have to zero it out because of NOEXEC */ \
	memset(&G, 0, sizeof(G)); \
} while (0)

enum {
	/* Must be in the same order as OP_conv_XXX! */
	/* (see "flags |= (1 << what)" below) */
	FLAG_NOTRUNC = (1 << 0) * ENABLE_FEATURE_DD_IBS_OBS,
	FLAG_SYNC    = (1 << 1) * ENABLE_FEATURE_DD_IBS_OBS,
	FLAG_NOERROR = (1 << 2) * ENABLE_FEATURE_DD_IBS_OBS,
	FLAG_FSYNC   = (1 << 3) * ENABLE_FEATURE_DD_IBS_OBS,
	FLAG_SWAB    = (1 << 4) * ENABLE_FEATURE_DD_IBS_OBS,
	/* end of conv flags */
	FLAG_TWOBUFS = (1 << 5) * ENABLE_FEATURE_DD_IBS_OBS,
	FLAG_COUNT   = 1 << 6,
	FLAG_STATUS  = 1 << 7,
	FLAG_STATUS_NONE = 1 << 7,
	FLAG_STATUS_NOXFER = 1 << 8,
};

static void dd_output_status(int UNUSED_PARAM cur_signal)
{
#if ENABLE_FEATURE_DD_THIRD_STATUS_LINE
	double seconds;
	unsigned long long bytes_sec;
	unsigned long long now_us = monotonic_us(); /* before fprintf */
#endif

	/* Deliberately using %u, not %d */
	fprintf(stderr, "%"OFF_FMT"u+%"OFF_FMT"u records in\n"
			"%"OFF_FMT"u+%"OFF_FMT"u records out\n",
			G.in_full, G.in_part,
			G.out_full, G.out_part);

#if ENABLE_FEATURE_DD_THIRD_STATUS_LINE
# if ENABLE_FEATURE_DD_STATUS
	if (G.flags & FLAG_STATUS_NOXFER) /* status=noxfer active? */
		return;
	//TODO: should status=none make dd stop reacting to USR1 entirely?
	//So far we react to it (we print the stats),
	//status=none only suppresses final, non-USR1 generated status message.
# endif
	fprintf(stderr, "%llu bytes (%sB) copied, ",
			G.total_bytes,
			/* show fractional digit, use suffixes */
			make_human_readable_str(G.total_bytes, 1, 0)
	);
	/* Corner cases:
	 * ./busybox dd </dev/null >/dev/null
	 * ./busybox dd bs=1M count=2000 </dev/zero >/dev/null
	 * (echo DONE) | ./busybox dd >/dev/null
	 * (sleep 1; echo DONE) | ./busybox dd >/dev/null
	 */
	seconds = (now_us - G.begin_time_us) / 1000000.0;
	bytes_sec = G.total_bytes / seconds;
	fprintf(stderr, "%f seconds, %sB/s\n",
			seconds,
			/* show fractional digit, use suffixes */
			make_human_readable_str(bytes_sec, 1, 0)
	);
#endif
}

static ssize_t full_write_or_warn(const void *buf, size_t len,
	const char *const filename)
{
	ssize_t n = full_write(ofd, buf, len);
	if (n < 0)
		bb_perror_msg("writing '%s'", filename);
	return n;
}

static bool write_and_stats(const void *buf, size_t len, size_t obs,
	const char *filename)
{
	ssize_t n = full_write_or_warn(buf, len, filename);
	if (n < 0)
		return 1;
	if ((size_t)n == obs)
		G.out_full++;
	else if (n) /* > 0 */
		G.out_part++;
#if ENABLE_FEATURE_DD_THIRD_STATUS_LINE
	G.total_bytes += n;
#endif
	return 0;
}

#if ENABLE_LFS
# define XATOU_SFX xatoull_sfx
#else
# define XATOU_SFX xatoul_sfx
#endif

int dd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int dd_main(int argc UNUSED_PARAM, char **argv)
{
	static const char keywords[] ALIGN1 =
		"bs\0""count\0""seek\0""skip\0""if\0""of\0"IF_FEATURE_DD_STATUS("status\0")
#if ENABLE_FEATURE_DD_IBS_OBS
		"ibs\0""obs\0""conv\0"
#endif
		;
#if ENABLE_FEATURE_DD_IBS_OBS
	static const char conv_words[] ALIGN1 =
		"notrunc\0""sync\0""noerror\0""fsync\0""swab\0";
#endif
#if ENABLE_FEATURE_DD_STATUS
	static const char status_words[] ALIGN1 =
		"none\0""noxfer\0";
#endif
	enum {
		OP_bs = 0,
		OP_count,
		OP_seek,
		OP_skip,
		OP_if,
		OP_of,
		IF_FEATURE_DD_STATUS(OP_status,)
#if ENABLE_FEATURE_DD_IBS_OBS
		OP_ibs,
		OP_obs,
		OP_conv,
		/* Must be in the same order as FLAG_XXX! */
		OP_conv_notrunc = 0,
		OP_conv_sync,
		OP_conv_noerror,
		OP_conv_fsync,
		OP_conv_swab,
	/* Unimplemented conv=XXX: */
	//nocreat       do not create the output file
	//excl          fail if the output file already exists
	//fdatasync     physically write output file data before finishing
	//lcase         change upper case to lower case
	//ucase         change lower case to upper case
	//block         pad newline-terminated records with spaces to cbs-size
	//unblock       replace trailing spaces in cbs-size records with newline
	//ascii         from EBCDIC to ASCII
	//ebcdic        from ASCII to EBCDIC
	//ibm           from ASCII to alternate EBCDIC
	/* Partially implemented: */
	//swab          swap every pair of input bytes: will abort on non-even reads
#endif
	};
	smallint exitcode = EXIT_FAILURE;
	int i;
	size_t ibs = 512;
	char *ibuf;
#if ENABLE_FEATURE_DD_IBS_OBS
	size_t obs = 512;
	char *obuf;
#else
# define obs  ibs
# define obuf ibuf
#endif
	/* These are all zeroed at once! */
	struct {
		size_t oc;
		ssize_t prev_read_size; /* for detecting swab failure */
		off_t count;
		off_t seek, skip;
		const char *infile, *outfile;
	} Z;
#define oc      (Z.oc     )
#define prev_read_size (Z.prev_read_size)
#define count   (Z.count  )
#define seek    (Z.seek   )
#define skip    (Z.skip   )
#define infile  (Z.infile )
#define outfile (Z.outfile)

	memset(&Z, 0, sizeof(Z));
	INIT_G();
	//fflush_all(); - is this needed because of NOEXEC?

	for (i = 1; argv[i]; i++) {
		int what;
		char *val;
		char *arg = argv[i];

#if ENABLE_DESKTOP
		/* "dd --". NB: coreutils 6.9 will complain if they see
		 * more than one of them. We wouldn't. */
		if (arg[0] == '-' && arg[1] == '-' && arg[2] == '\0')
			continue;
#endif
		val = strchr(arg, '=');
		if (val == NULL)
			bb_show_usage();
		*val = '\0';
		what = index_in_strings(keywords, arg);
		if (what < 0)
			bb_show_usage();
		/* *val = '='; - to preserve ps listing? */
		val++;
#if ENABLE_FEATURE_DD_IBS_OBS
		if (what == OP_ibs) {
			/* Must fit into positive ssize_t */
			ibs = xatoul_range_sfx(val, 1, ((size_t)-1L)/2, dd_suffixes);
			/*continue;*/
		}
		if (what == OP_obs) {
			obs = xatoul_range_sfx(val, 1, ((size_t)-1L)/2, dd_suffixes);
			/*continue;*/
		}
		if (what == OP_conv) {
			while (1) {
				int n;
				/* find ',', replace them with NUL so we can use val for
				 * index_in_strings() without copying.
				 * We rely on val being non-null, else strchr would fault.
				 */
				arg = strchr(val, ',');
				if (arg)
					*arg = '\0';
				n = index_in_strings(conv_words, val);
				if (n < 0)
					bb_error_msg_and_die(bb_msg_invalid_arg, val, "conv");
				G.flags |= (1 << n);
				if (!arg) /* no ',' left, so this was the last specifier */
					break;
				/* *arg = ','; - to preserve ps listing? */
				val = arg + 1; /* skip this keyword and ',' */
			}
			/*continue;*/
		}
#endif
		if (what == OP_bs) {
			ibs = xatoul_range_sfx(val, 1, ((size_t)-1L)/2, dd_suffixes);
			obs = ibs;
			/*continue;*/
		}
		/* These can be large: */
		if (what == OP_count) {
			G.flags |= FLAG_COUNT;
			count = XATOU_SFX(val, dd_suffixes);
			/*continue;*/
		}
		if (what == OP_seek) {
			seek = XATOU_SFX(val, dd_suffixes);
			/*continue;*/
		}
		if (what == OP_skip) {
			skip = XATOU_SFX(val, dd_suffixes);
			/*continue;*/
		}
		if (what == OP_if) {
			infile = val;
			/*continue;*/
		}
		if (what == OP_of) {
			outfile = val;
			/*continue;*/
		}
#if ENABLE_FEATURE_DD_STATUS
		if (what == OP_status) {
			int n;
			n = index_in_strings(status_words, val);
			if (n < 0)
				bb_error_msg_and_die(bb_msg_invalid_arg, val, "status");
			G.flags |= FLAG_STATUS << n;
			/*continue;*/
		}
#endif
	} /* end of "for (argv[i])" */

//XXX:FIXME for huge ibs or obs, malloc'ing them isn't the brightest idea ever
	ibuf = xmalloc(ibs);
	obuf = ibuf;
#if ENABLE_FEATURE_DD_IBS_OBS
	if (ibs != obs) {
		G.flags |= FLAG_TWOBUFS;
		obuf = xmalloc(obs);
	}
#endif

#if ENABLE_FEATURE_DD_SIGNAL_HANDLING
	signal_SA_RESTART_empty_mask(SIGUSR1, dd_output_status);
#endif
#if ENABLE_FEATURE_DD_THIRD_STATUS_LINE
	G.begin_time_us = monotonic_us();
#endif

	if (infile) {
		xmove_fd(xopen(infile, O_RDONLY), ifd);
	} else {
		infile = bb_msg_standard_input;
	}
	if (outfile) {
		int oflag = O_WRONLY | O_CREAT;

		if (!seek && !(G.flags & FLAG_NOTRUNC))
			oflag |= O_TRUNC;

		xmove_fd(xopen(outfile, oflag), ofd);

		if (seek && !(G.flags & FLAG_NOTRUNC)) {
			if (ftruncate(ofd, seek * obs) < 0) {
				struct stat st;

				if (fstat(ofd, &st) < 0
				 || S_ISREG(st.st_mode)
				 || S_ISDIR(st.st_mode)
				) {
					goto die_outfile;
				}
			}
		}
	} else {
		outfile = bb_msg_standard_output;
	}
	if (skip) {
		if (lseek(ifd, skip * ibs, SEEK_CUR) < 0) {
			do {
				ssize_t n = safe_read(ifd, ibuf, ibs);
				if (n < 0)
					goto die_infile;
				if (n == 0)
					break;
			} while (--skip != 0);
		}
	}
	if (seek) {
		if (lseek(ofd, seek * obs, SEEK_CUR) < 0)
			goto die_outfile;
	}

	while (!(G.flags & FLAG_COUNT) || (G.in_full + G.in_part != count)) {
		ssize_t n;

		n = safe_read(ifd, ibuf, ibs);
		if (n == 0)
			break;
		if (n < 0) {
			/* "Bad block" */
			if (!(G.flags & FLAG_NOERROR))
				goto die_infile;
			bb_simple_perror_msg(infile);
			/* GNU dd with conv=noerror skips over bad blocks */
			xlseek(ifd, ibs, SEEK_CUR);
			/* conv=noerror,sync writes NULs,
			 * conv=noerror just ignores input bad blocks */
			n = 0;
		}
		if (G.flags & FLAG_SWAB) {
			uint16_t *p16;
			ssize_t n2;

			/* Our code allows only last read to be odd-sized */
			if (prev_read_size & 1)
				bb_error_msg_and_die("can't swab %lu byte buffer",
						(unsigned long)prev_read_size);
			prev_read_size = n;

			/* If n is odd, last byte is not swapped:
			 *  echo -n "qwe" | dd conv=swab
			 * prints "wqe".
			 */
			p16 = (void*) ibuf;
			n2 = (n >> 1);
			while (--n2 >= 0) {
				*p16 = bswap_16(*p16);
				p16++;
			}
		}
		if ((size_t)n == ibs)
			G.in_full++;
		else {
			G.in_part++;
			if (G.flags & FLAG_SYNC) {
				memset(ibuf + n, 0, ibs - n);
				n = ibs;
			}
		}
		if (G.flags & FLAG_TWOBUFS) {
			char *tmp = ibuf;
			while (n) {
				size_t d = obs - oc;

				if (d > (size_t)n)
					d = n;
				memcpy(obuf + oc, tmp, d);
				n -= d;
				tmp += d;
				oc += d;
				if (oc == obs) {
					if (write_and_stats(obuf, obs, obs, outfile))
						goto out_status;
					oc = 0;
				}
			}
		} else {
			if (write_and_stats(ibuf, n, obs, outfile))
				goto out_status;
		}

		if (G.flags & FLAG_FSYNC) {
			if (fsync(ofd) < 0)
				goto die_outfile;
		}
	}

	if (ENABLE_FEATURE_DD_IBS_OBS && oc) {
		if (write_and_stats(obuf, oc, obs, outfile))
			goto out_status;
	}
	if (close(ifd) < 0) {
 die_infile:
		bb_simple_perror_msg_and_die(infile);
	}

	if (close(ofd) < 0) {
 die_outfile:
		bb_simple_perror_msg_and_die(outfile);
	}

	exitcode = EXIT_SUCCESS;
 out_status:
	if (!ENABLE_FEATURE_DD_STATUS || !(G.flags & FLAG_STATUS_NONE))
		dd_output_status(0);

	if (ENABLE_FEATURE_CLEAN_UP) {
		free(obuf);
		if (G.flags & FLAG_TWOBUFS)
			free(ibuf);
	}

	return exitcode;
}