busybox/coreutils/dd.c

/* 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 tarball for details.
 */

#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 },
	{ "kD", 1000 },
	{ "k", 1024 },
	{ "K", 1024 },	/* compat with coreutils dd */
	{ "MD", 1000000 },
	{ "M", 1048576 },
	{ "GD", 1000000000 },
	{ "G", 1073741824 },
	{ "", 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
};
#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)


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
	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)
{
	enum {
		/* Must be in the same order as OP_conv_XXX! */
		/* (see "flags |= (1 << what)" below) */
		FLAG_NOTRUNC = 1 << 0,
		FLAG_SYNC    = 1 << 1,
		FLAG_NOERROR = 1 << 2,
		FLAG_FSYNC   = 1 << 3,
		/* end of conv flags */
		FLAG_TWOBUFS = 1 << 4,
		FLAG_COUNT   = 1 << 5,
	};
	static const char keywords[] ALIGN1 =
		"bs\0""count\0""seek\0""skip\0""if\0""of\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";
#endif
	enum {
		OP_bs = 0,
		OP_count,
		OP_seek,
		OP_skip,
		OP_if,
		OP_of,
#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,
	/* 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
	//swab          swap every pair of input bytes
	//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
#endif
	};
	int exitcode = EXIT_FAILURE;
	size_t ibs = 512, obs = 512;
	ssize_t n, w;
	char *ibuf, *obuf;
	/* And these are all zeroed at once! */
	struct {
		int flags;
		size_t oc;
		off_t count;
		off_t seek, skip;
		const char *infile, *outfile;
	} Z;
#define flags   (Z.flags  )
#define oc      (Z.oc     )
#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 (n = 1; argv[n]; n++) {
		int what;
		char *val;
		char *arg = argv[n];

#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) {
				/* 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';
				what = index_in_strings(conv_words, val);
				if (what < 0)
					bb_error_msg_and_die(bb_msg_invalid_arg, val, "conv");
				flags |= (1 << what);
				if (!arg) /* no ',' left, so this was the last specifier */
					break;
				/* *arg = ','; - to preserve ps listing? */
				val = arg + 1; /* skip this keyword and ',' */
			}
			continue; /* we trashed 'what', can't fall through */
		}
#endif
		if (what == OP_bs) {
			ibs = obs = xatoul_range_sfx(val, 1, ((size_t)-1L)/2, dd_suffixes);
			/*continue;*/
		}
		/* These can be large: */
		if (what == OP_count) {
			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;*/
		}
	} /* end of "for (argv[n])" */

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

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

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

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

		if (seek && !(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) {
			while (skip-- > 0) {
				n = safe_read(ifd, ibuf, ibs);
				if (n < 0)
					goto die_infile;
				if (n == 0)
					break;
			}
		}
	}
	if (seek) {
		if (lseek(ofd, seek * obs, SEEK_CUR) < 0)
			goto die_outfile;
	}

	while (!(flags & FLAG_COUNT) || (G.in_full + G.in_part != count)) {
		n = safe_read(ifd, ibuf, ibs);
		if (n == 0)
			break;
		if (n < 0) {
			/* "Bad block" */
			if (!(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 ((size_t)n == ibs)
			G.in_full++;
		else {
			G.in_part++;
			if (flags & FLAG_SYNC) {
				memset(ibuf + n, 0, ibs - n);
				n = ibs;
			}
		}
		if (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 (flags & FLAG_FSYNC) {
			if (fsync(ofd) < 0)
				goto die_outfile;
		}
	}

	if (ENABLE_FEATURE_DD_IBS_OBS && oc) {
		w = full_write_or_warn(obuf, oc, outfile);
		if (w < 0) goto out_status;
		if (w > 0) G.out_part++;
	}
	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:
	dd_output_status(0);

	return exitcode;
}
1	/* vi: set sw=4 ts=4: */
2	/*
3	* Mini dd implementation for busybox
4	*
5	*
6	* Copyright (C) 2000,2001 Matt Kraai
7	*
8	* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
9	*/
10
11	#include "libbb.h"
12
13	/* This is a NOEXEC applet. Be very careful! */
14
15
16	enum {
17	ifd = STDIN_FILENO,
18	ofd = STDOUT_FILENO,
19	};
20
21	static const struct suffix_mult dd_suffixes[] = {
22	{ "c", 1 },
23	{ "w", 2 },
24	{ "b", 512 },
25	{ "kD", 1000 },
26	{ "k", 1024 },
27	{ "K", 1024 }, /* compat with coreutils dd */
28	{ "MD", 1000000 },
29	{ "M", 1048576 },
30	{ "GD", 1000000000 },
31	{ "G", 1073741824 },
32	{ "", 0 }
33	};
34
35	struct globals {
36	off_t out_full, out_part, in_full, in_part;
37	#if ENABLE_FEATURE_DD_THIRD_STATUS_LINE
38	unsigned long long total_bytes;
39	unsigned long long begin_time_us;
40	#endif
41	};
42	#define G ((struct globals)&bb_common_bufsiz1)
43	#define INIT_G() do { \
44	/* we have to zero it out because of NOEXEC */ \
45	memset(&G, 0, sizeof(G)); \
46	} while (0)
47
48
49	static void dd_output_status(int UNUSED_PARAM cur_signal)
50	{
51	#if ENABLE_FEATURE_DD_THIRD_STATUS_LINE
52	double seconds;
53	unsigned long long bytes_sec;
54	unsigned long long now_us = monotonic_us(); /* before fprintf */
55	#endif
56
57	/* Deliberately using %u, not %d */
58	fprintf(stderr, "%"OFF_FMT"u+%"OFF_FMT"u records in\n"
59	"%"OFF_FMT"u+%"OFF_FMT"u records out\n",
60	G.in_full, G.in_part,
61	G.out_full, G.out_part);
62
63	#if ENABLE_FEATURE_DD_THIRD_STATUS_LINE
64	fprintf(stderr, "%llu bytes (%sB) copied, ",
65	G.total_bytes,
66	/* show fractional digit, use suffixes */
67	make_human_readable_str(G.total_bytes, 1, 0)
68	);
69	/* Corner cases:
70	* ./busybox dd </dev/null >/dev/null
71	* ./busybox dd bs=1M count=2000 </dev/zero >/dev/null
72	* (echo DONE) \| ./busybox dd >/dev/null
73	* (sleep 1; echo DONE) \| ./busybox dd >/dev/null
74	*/
75	seconds = (now_us - G.begin_time_us) / 1000000.0;
76	bytes_sec = G.total_bytes / seconds;
77	fprintf(stderr, "%f seconds, %sB/s\n",
78	seconds,
79	/* show fractional digit, use suffixes */
80	make_human_readable_str(bytes_sec, 1, 0)
81	);
82	#endif
83	}
84
85	static ssize_t full_write_or_warn(const void *buf, size_t len,
86	const char *const filename)
87	{
88	ssize_t n = full_write(ofd, buf, len);
89	if (n < 0)
90	bb_perror_msg("writing '%s'", filename);
91	return n;
92	}
93
94	static bool write_and_stats(const void *buf, size_t len, size_t obs,
95	const char *filename)
96	{
97	ssize_t n = full_write_or_warn(buf, len, filename);
98	if (n < 0)
99	return 1;
100	if ((size_t)n == obs)
101	G.out_full++;
102	else if (n) /* > 0 */
103	G.out_part++;
104	#if ENABLE_FEATURE_DD_THIRD_STATUS_LINE
105	G.total_bytes += n;
106	#endif
107	return 0;
108	}
109
110	#if ENABLE_LFS
111	# define XATOU_SFX xatoull_sfx
112	#else
113	# define XATOU_SFX xatoul_sfx
114	#endif
115
116	int dd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
117	int dd_main(int argc UNUSED_PARAM, char **argv)
118	{
119	enum {
120	/* Must be in the same order as OP_conv_XXX! */
121	/* (see "flags \|= (1 << what)" below) */
122	FLAG_NOTRUNC = 1 << 0,
123	FLAG_SYNC = 1 << 1,
124	FLAG_NOERROR = 1 << 2,
125	FLAG_FSYNC = 1 << 3,
126	/* end of conv flags */
127	FLAG_TWOBUFS = 1 << 4,
128	FLAG_COUNT = 1 << 5,
129	};
130	static const char keywords[] ALIGN1 =
131	"bs\0""count\0""seek\0""skip\0""if\0""of\0"
132	#if ENABLE_FEATURE_DD_IBS_OBS
133	"ibs\0""obs\0""conv\0"
134	#endif
135	;
136	#if ENABLE_FEATURE_DD_IBS_OBS
137	static const char conv_words[] ALIGN1 =
138	"notrunc\0""sync\0""noerror\0""fsync\0";
139	#endif
140	enum {
141	OP_bs = 0,
142	OP_count,
143	OP_seek,
144	OP_skip,
145	OP_if,
146	OP_of,
147	#if ENABLE_FEATURE_DD_IBS_OBS
148	OP_ibs,
149	OP_obs,
150	OP_conv,
151	/* Must be in the same order as FLAG_XXX! */
152	OP_conv_notrunc = 0,
153	OP_conv_sync,
154	OP_conv_noerror,
155	OP_conv_fsync,
156	/* Unimplemented conv=XXX: */
157	//nocreat do not create the output file
158	//excl fail if the output file already exists
159	//fdatasync physically write output file data before finishing
160	//swab swap every pair of input bytes
161	//lcase change upper case to lower case
162	//ucase change lower case to upper case
163	//block pad newline-terminated records with spaces to cbs-size
164	//unblock replace trailing spaces in cbs-size records with newline
165	//ascii from EBCDIC to ASCII
166	//ebcdic from ASCII to EBCDIC
167	//ibm from ASCII to alternate EBCDIC
168	#endif
169	};
170	int exitcode = EXIT_FAILURE;
171	size_t ibs = 512, obs = 512;
172	ssize_t n, w;
173	char ibuf, obuf;
174	/* And these are all zeroed at once! */
175	struct {
176	int flags;
177	size_t oc;
178	off_t count;
179	off_t seek, skip;
180	const char infile, outfile;
181	} Z;
182	#define flags (Z.flags )
183	#define oc (Z.oc )
184	#define count (Z.count )
185	#define seek (Z.seek )
186	#define skip (Z.skip )
187	#define infile (Z.infile )
188	#define outfile (Z.outfile)
189
190	memset(&Z, 0, sizeof(Z));
191	INIT_G();
192	//fflush_all(); - is this needed because of NOEXEC?
193
194	for (n = 1; argv[n]; n++) {
195	int what;
196	char *val;
197	char *arg = argv[n];
198
199	#if ENABLE_DESKTOP
200	/* "dd --". NB: coreutils 6.9 will complain if they see
201	* more than one of them. We wouldn't. */
202	if (arg[0] == '-' && arg[1] == '-' && arg[2] == '\0')
203	continue;
204	#endif
205	val = strchr(arg, '=');
206	if (val == NULL)
207	bb_show_usage();
208	*val = '\0';
209	what = index_in_strings(keywords, arg);
210	if (what < 0)
211	bb_show_usage();
212	/* val = '='; - to preserve ps listing? /
213	val++;
214	#if ENABLE_FEATURE_DD_IBS_OBS
215	if (what == OP_ibs) {
216	/* Must fit into positive ssize_t */
217	ibs = xatoul_range_sfx(val, 1, ((size_t)-1L)/2, dd_suffixes);
218	/continue;/
219	}
220	if (what == OP_obs) {
221	obs = xatoul_range_sfx(val, 1, ((size_t)-1L)/2, dd_suffixes);
222	/continue;/
223	}
224	if (what == OP_conv) {
225	while (1) {
226	/* find ',', replace them with NUL so we can use val for
227	* index_in_strings() without copying.
228	* We rely on val being non-null, else strchr would fault.
229	*/
230	arg = strchr(val, ',');
231	if (arg)
232	*arg = '\0';
233	what = index_in_strings(conv_words, val);
234	if (what < 0)
235	bb_error_msg_and_die(bb_msg_invalid_arg, val, "conv");
236	flags \|= (1 << what);
237	if (!arg) /* no ',' left, so this was the last specifier */
238	break;
239	/* arg = ','; - to preserve ps listing? /
240	val = arg + 1; /* skip this keyword and ',' */
241	}
242	continue; /* we trashed 'what', can't fall through */
243	}
244	#endif
245	if (what == OP_bs) {
246	ibs = obs = xatoul_range_sfx(val, 1, ((size_t)-1L)/2, dd_suffixes);
247	/continue;/
248	}
249	/* These can be large: */
250	if (what == OP_count) {
251	flags \|= FLAG_COUNT;
252	count = XATOU_SFX(val, dd_suffixes);
253	/continue;/
254	}
255	if (what == OP_seek) {
256	seek = XATOU_SFX(val, dd_suffixes);
257	/continue;/
258	}
259	if (what == OP_skip) {
260	skip = XATOU_SFX(val, dd_suffixes);
261	/continue;/
262	}
263	if (what == OP_if) {
264	infile = val;
265	/continue;/
266	}
267	if (what == OP_of) {
268	outfile = val;
269	/continue;/
270	}
271	} /* end of "for (argv[n])" */
272
273	//XXX:FIXME for huge ibs or obs, malloc'ing them isn't the brightest idea ever
274	ibuf = obuf = xmalloc(ibs);
275	if (ibs != obs) {
276	flags \|= FLAG_TWOBUFS;
277	obuf = xmalloc(obs);
278	}
279
280	#if ENABLE_FEATURE_DD_SIGNAL_HANDLING
281	signal_SA_RESTART_empty_mask(SIGUSR1, dd_output_status);
282	#endif
283	#if ENABLE_FEATURE_DD_THIRD_STATUS_LINE
284	G.begin_time_us = monotonic_us();
285	#endif
286
287	if (infile != NULL)
288	xmove_fd(xopen(infile, O_RDONLY), ifd);
289	else {
290	infile = bb_msg_standard_input;
291	}
292	if (outfile != NULL) {
293	int oflag = O_WRONLY \| O_CREAT;
294
295	if (!seek && !(flags & FLAG_NOTRUNC))
296	oflag \|= O_TRUNC;
297
298	xmove_fd(xopen(outfile, oflag), ofd);
299
300	if (seek && !(flags & FLAG_NOTRUNC)) {
301	if (ftruncate(ofd, seek * obs) < 0) {
302	struct stat st;
303
304	if (fstat(ofd, &st) < 0 \|\| S_ISREG(st.st_mode) \|\|
305	S_ISDIR(st.st_mode))
306	goto die_outfile;
307	}
308	}
309	} else {
310	outfile = bb_msg_standard_output;
311	}
312	if (skip) {
313	if (lseek(ifd, skip * ibs, SEEK_CUR) < 0) {
314	while (skip-- > 0) {
315	n = safe_read(ifd, ibuf, ibs);
316	if (n < 0)
317	goto die_infile;
318	if (n == 0)
319	break;
320	}
321	}
322	}
323	if (seek) {
324	if (lseek(ofd, seek * obs, SEEK_CUR) < 0)
325	goto die_outfile;
326	}
327
328	while (!(flags & FLAG_COUNT) \|\| (G.in_full + G.in_part != count)) {
329	n = safe_read(ifd, ibuf, ibs);
330	if (n == 0)
331	break;
332	if (n < 0) {
333	/* "Bad block" */
334	if (!(flags & FLAG_NOERROR))
335	goto die_infile;
336	bb_simple_perror_msg(infile);
337	/* GNU dd with conv=noerror skips over bad blocks */
338	xlseek(ifd, ibs, SEEK_CUR);
339	/* conv=noerror,sync writes NULs,
340	* conv=noerror just ignores input bad blocks */
341	n = 0;
342	}
343	if ((size_t)n == ibs)
344	G.in_full++;
345	else {
346	G.in_part++;
347	if (flags & FLAG_SYNC) {
348	memset(ibuf + n, 0, ibs - n);
349	n = ibs;
350	}
351	}
352	if (flags & FLAG_TWOBUFS) {
353	char *tmp = ibuf;
354	while (n) {
355	size_t d = obs - oc;
356
357	if (d > (size_t)n)
358	d = n;
359	memcpy(obuf + oc, tmp, d);
360	n -= d;
361	tmp += d;
362	oc += d;
363	if (oc == obs) {
364	if (write_and_stats(obuf, obs, obs, outfile))
365	goto out_status;
366	oc = 0;
367	}
368	}
369	} else if (write_and_stats(ibuf, n, obs, outfile))
370	goto out_status;
371
372	if (flags & FLAG_FSYNC) {
373	if (fsync(ofd) < 0)
374	goto die_outfile;
375	}
376	}
377
378	if (ENABLE_FEATURE_DD_IBS_OBS && oc) {
379	w = full_write_or_warn(obuf, oc, outfile);
380	if (w < 0) goto out_status;
381	if (w > 0) G.out_part++;
382	}
383	if (close(ifd) < 0) {
384	die_infile:
385	bb_simple_perror_msg_and_die(infile);
386	}
387
388	if (close(ofd) < 0) {
389	die_outfile:
390	bb_simple_perror_msg_and_die(outfile);
391	}
392
393	exitcode = EXIT_SUCCESS;
394	out_status:
395	dd_output_status(0);
396
397	return exitcode;
398	}