dd.c revision 239991 
1/*-
2 * Copyright (c) 1991, 1993, 1994
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * Keith Muller of the University of California, San Diego and Lance
7 * Visser of Convex Computer Corporation.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 *    notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 *    notice, this list of conditions and the following disclaimer in the
16 *    documentation and/or other materials provided with the distribution.
17 * 4. Neither the name of the University nor the names of its contributors
18 *    may be used to endorse or promote products derived from this software
19 *    without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34#if 0
35#ifndef lint
36static char const copyright[] =
37"@(#) Copyright (c) 1991, 1993, 1994\n\
38	The Regents of the University of California.  All rights reserved.\n";
39#endif /* not lint */
40
41#ifndef lint
42static char sccsid[] = "@(#)dd.c	8.5 (Berkeley) 4/2/94";
43#endif /* not lint */
44#endif
45#include <sys/cdefs.h>
46__FBSDID("$FreeBSD: head/bin/dd/dd.c 239991 2012-09-01 14:45:15Z ed $");
47
48#include <sys/param.h>
49#include <sys/stat.h>
50#include <sys/conf.h>
51#include <sys/disklabel.h>
52#include <sys/filio.h>
53#include <sys/time.h>
54
55#include <ctype.h>
56#include <err.h>
57#include <errno.h>
58#include <fcntl.h>
59#include <inttypes.h>
60#include <locale.h>
61#include <stdio.h>
62#include <stdlib.h>
63#include <string.h>
64#include <unistd.h>
65
66#include "dd.h"
67#include "extern.h"
68
69static void dd_close(void);
70static void dd_in(void);
71static void getfdtype(IO *);
72static void setup(void);
73
74IO	in, out;		/* input/output state */
75STAT	st;			/* statistics */
76void	(*cfunc)(void);		/* conversion function */
77uintmax_t cpy_cnt;		/* # of blocks to copy */
78static off_t	pending = 0;	/* pending seek if sparse */
79u_int	ddflags = 0;		/* conversion options */
80size_t	cbsz;			/* conversion block size */
81uintmax_t files_cnt = 1;	/* # of files to copy */
82const	u_char *ctab;		/* conversion table */
83char	fill_char;		/* Character to fill with if defined */
84
85int
86main(int argc __unused, char *argv[])
87{
88	(void)setlocale(LC_CTYPE, "");
89	jcl(argv);
90	setup();
91
92	(void)signal(SIGINFO, summaryx);
93	(void)signal(SIGINT, terminate);
94
95	atexit(summary);
96
97	while (files_cnt--)
98		dd_in();
99
100	dd_close();
101	exit(0);
102}
103
104static int
105parity(u_char c)
106{
107	int i;
108
109	i = c ^ (c >> 1) ^ (c >> 2) ^ (c >> 3) ^
110	    (c >> 4) ^ (c >> 5) ^ (c >> 6) ^ (c >> 7);
111	return (i & 1);
112}
113
114static void
115setup(void)
116{
117	u_int cnt;
118	struct timeval tv;
119
120	if (in.name == NULL) {
121		in.name = "stdin";
122		in.fd = STDIN_FILENO;
123	} else {
124		in.fd = open(in.name, O_RDONLY, 0);
125		if (in.fd == -1)
126			err(1, "%s", in.name);
127	}
128
129	getfdtype(&in);
130
131	if (files_cnt > 1 && !(in.flags & ISTAPE))
132		errx(1, "files is not supported for non-tape devices");
133
134	if (out.name == NULL) {
135		/* No way to check for read access here. */
136		out.fd = STDOUT_FILENO;
137		out.name = "stdout";
138	} else {
139#define	OFLAGS \
140    (O_CREAT | (ddflags & (C_SEEK | C_NOTRUNC) ? 0 : O_TRUNC))
141		out.fd = open(out.name, O_RDWR | OFLAGS, DEFFILEMODE);
142		/*
143		 * May not have read access, so try again with write only.
144		 * Without read we may have a problem if output also does
145		 * not support seeks.
146		 */
147		if (out.fd == -1) {
148			out.fd = open(out.name, O_WRONLY | OFLAGS, DEFFILEMODE);
149			out.flags |= NOREAD;
150		}
151		if (out.fd == -1)
152			err(1, "%s", out.name);
153	}
154
155	getfdtype(&out);
156
157	/*
158	 * Allocate space for the input and output buffers.  If not doing
159	 * record oriented I/O, only need a single buffer.
160	 */
161	if (!(ddflags & (C_BLOCK | C_UNBLOCK))) {
162		if ((in.db = malloc(out.dbsz + in.dbsz - 1)) == NULL)
163			err(1, "input buffer");
164		out.db = in.db;
165	} else if ((in.db = malloc(MAX(in.dbsz, cbsz) + cbsz)) == NULL ||
166	    (out.db = malloc(out.dbsz + cbsz)) == NULL)
167		err(1, "output buffer");
168	in.dbp = in.db;
169	out.dbp = out.db;
170
171	/* Position the input/output streams. */
172	if (in.offset)
173		pos_in();
174	if (out.offset)
175		pos_out();
176
177	/*
178	 * Truncate the output file.  If it fails on a type of output file
179	 * that it should _not_ fail on, error out.
180	 */
181	if ((ddflags & (C_OF | C_SEEK | C_NOTRUNC)) == (C_OF | C_SEEK) &&
182	    out.flags & ISTRUNC)
183		if (ftruncate(out.fd, out.offset * out.dbsz) == -1)
184			err(1, "truncating %s", out.name);
185
186	if (ddflags & (C_LCASE  | C_UCASE | C_ASCII | C_EBCDIC | C_PARITY)) {
187		if (ctab != NULL) {
188			for (cnt = 0; cnt <= 0377; ++cnt)
189				casetab[cnt] = ctab[cnt];
190		} else {
191			for (cnt = 0; cnt <= 0377; ++cnt)
192				casetab[cnt] = cnt;
193		}
194		if ((ddflags & C_PARITY) && !(ddflags & C_ASCII)) {
195			/*
196			 * If the input is not EBCDIC, and we do parity
197			 * processing, strip input parity.
198			 */
199			for (cnt = 200; cnt <= 0377; ++cnt)
200				casetab[cnt] = casetab[cnt & 0x7f];
201		}
202		if (ddflags & C_LCASE) {
203			for (cnt = 0; cnt <= 0377; ++cnt)
204				casetab[cnt] = tolower(casetab[cnt]);
205		} else if (ddflags & C_UCASE) {
206			for (cnt = 0; cnt <= 0377; ++cnt)
207				casetab[cnt] = toupper(casetab[cnt]);
208		}
209		if ((ddflags & C_PARITY)) {
210			/*
211			 * This should strictly speaking be a no-op, but I
212			 * wonder what funny LANG settings could get us.
213			 */
214			for (cnt = 0; cnt <= 0377; ++cnt)
215				casetab[cnt] = casetab[cnt] & 0x7f;
216		}
217		if ((ddflags & C_PARSET)) {
218			for (cnt = 0; cnt <= 0377; ++cnt)
219				casetab[cnt] = casetab[cnt] | 0x80;
220		}
221		if ((ddflags & C_PAREVEN)) {
222			for (cnt = 0; cnt <= 0377; ++cnt)
223				if (parity(casetab[cnt]))
224					casetab[cnt] = casetab[cnt] | 0x80;
225		}
226		if ((ddflags & C_PARODD)) {
227			for (cnt = 0; cnt <= 0377; ++cnt)
228				if (!parity(casetab[cnt]))
229					casetab[cnt] = casetab[cnt] | 0x80;
230		}
231
232		ctab = casetab;
233	}
234
235	(void)gettimeofday(&tv, NULL);
236	st.start = tv.tv_sec + tv.tv_usec * 1e-6;
237}
238
239static void
240getfdtype(IO *io)
241{
242	struct stat sb;
243	int type;
244
245	if (fstat(io->fd, &sb) == -1)
246		err(1, "%s", io->name);
247	if (S_ISREG(sb.st_mode))
248		io->flags |= ISTRUNC;
249	if (S_ISCHR(sb.st_mode) || S_ISBLK(sb.st_mode)) {
250		if (ioctl(io->fd, FIODTYPE, &type) == -1) {
251			err(1, "%s", io->name);
252		} else {
253			if (type & D_TAPE)
254				io->flags |= ISTAPE;
255			else if (type & (D_DISK | D_MEM))
256				io->flags |= ISSEEK;
257			if (S_ISCHR(sb.st_mode) && (type & D_TAPE) == 0)
258				io->flags |= ISCHR;
259		}
260		return;
261	}
262	errno = 0;
263	if (lseek(io->fd, (off_t)0, SEEK_CUR) == -1 && errno == ESPIPE)
264		io->flags |= ISPIPE;
265	else
266		io->flags |= ISSEEK;
267}
268
269static void
270dd_in(void)
271{
272	ssize_t n;
273
274	for (;;) {
275		switch (cpy_cnt) {
276		case -1:			/* count=0 was specified */
277			return;
278		case 0:
279			break;
280		default:
281			if (st.in_full + st.in_part >= (uintmax_t)cpy_cnt)
282				return;
283			break;
284		}
285
286		/*
287		 * Zero the buffer first if sync; if doing block operations,
288		 * use spaces.
289		 */
290		if (ddflags & C_SYNC) {
291			if (ddflags & C_FILL)
292				memset(in.dbp, fill_char, in.dbsz);
293			else if (ddflags & (C_BLOCK | C_UNBLOCK))
294				memset(in.dbp, ' ', in.dbsz);
295			else
296				memset(in.dbp, 0, in.dbsz);
297		}
298
299		n = read(in.fd, in.dbp, in.dbsz);
300		if (n == 0) {
301			in.dbrcnt = 0;
302			return;
303		}
304
305		/* Read error. */
306		if (n == -1) {
307			/*
308			 * If noerror not specified, die.  POSIX requires that
309			 * the warning message be followed by an I/O display.
310			 */
311			if (!(ddflags & C_NOERROR))
312				err(1, "%s", in.name);
313			warn("%s", in.name);
314			summary();
315
316			/*
317			 * If it's a seekable file descriptor, seek past the
318			 * error.  If your OS doesn't do the right thing for
319			 * raw disks this section should be modified to re-read
320			 * in sector size chunks.
321			 */
322			if (in.flags & ISSEEK &&
323			    lseek(in.fd, (off_t)in.dbsz, SEEK_CUR))
324				warn("%s", in.name);
325
326			/* If sync not specified, omit block and continue. */
327			if (!(ddflags & C_SYNC))
328				continue;
329
330			/* Read errors count as full blocks. */
331			in.dbcnt += in.dbrcnt = in.dbsz;
332			++st.in_full;
333
334		/* Handle full input blocks. */
335		} else if ((size_t)n == in.dbsz) {
336			in.dbcnt += in.dbrcnt = n;
337			++st.in_full;
338
339		/* Handle partial input blocks. */
340		} else {
341			/* If sync, use the entire block. */
342			if (ddflags & C_SYNC)
343				in.dbcnt += in.dbrcnt = in.dbsz;
344			else
345				in.dbcnt += in.dbrcnt = n;
346			++st.in_part;
347		}
348
349		/*
350		 * POSIX states that if bs is set and no other conversions
351		 * than noerror, notrunc or sync are specified, the block
352		 * is output without buffering as it is read.
353		 */
354		if (ddflags & C_BS) {
355			out.dbcnt = in.dbcnt;
356			dd_out(1);
357			in.dbcnt = 0;
358			continue;
359		}
360
361		if (ddflags & C_SWAB) {
362			if ((n = in.dbrcnt) & 1) {
363				++st.swab;
364				--n;
365			}
366			swab(in.dbp, in.dbp, (size_t)n);
367		}
368
369		in.dbp += in.dbrcnt;
370		(*cfunc)();
371	}
372}
373
374/*
375 * Clean up any remaining I/O and flush output.  If necessary, the output file
376 * is truncated.
377 */
378static void
379dd_close(void)
380{
381	if (cfunc == def)
382		def_close();
383	else if (cfunc == block)
384		block_close();
385	else if (cfunc == unblock)
386		unblock_close();
387	if (ddflags & C_OSYNC && out.dbcnt && out.dbcnt < out.dbsz) {
388		if (ddflags & C_FILL)
389			memset(out.dbp, fill_char, out.dbsz - out.dbcnt);
390		else if (ddflags & (C_BLOCK | C_UNBLOCK))
391			memset(out.dbp, ' ', out.dbsz - out.dbcnt);
392		else
393			memset(out.dbp, 0, out.dbsz - out.dbcnt);
394		out.dbcnt = out.dbsz;
395	}
396	if (out.dbcnt || pending)
397		dd_out(1);
398}
399
400void
401dd_out(int force)
402{
403	u_char *outp;
404	size_t cnt, i, n;
405	ssize_t nw;
406	static int warned;
407	int sparse;
408
409	/*
410	 * Write one or more blocks out.  The common case is writing a full
411	 * output block in a single write; increment the full block stats.
412	 * Otherwise, we're into partial block writes.  If a partial write,
413	 * and it's a character device, just warn.  If a tape device, quit.
414	 *
415	 * The partial writes represent two cases.  1: Where the input block
416	 * was less than expected so the output block was less than expected.
417	 * 2: Where the input block was the right size but we were forced to
418	 * write the block in multiple chunks.  The original versions of dd(1)
419	 * never wrote a block in more than a single write, so the latter case
420	 * never happened.
421	 *
422	 * One special case is if we're forced to do the write -- in that case
423	 * we play games with the buffer size, and it's usually a partial write.
424	 */
425	outp = out.db;
426	for (n = force ? out.dbcnt : out.dbsz;; n = out.dbsz) {
427		for (cnt = n;; cnt -= nw) {
428			sparse = 0;
429			if (ddflags & C_SPARSE) {
430				sparse = 1;	/* Is buffer sparse? */
431				for (i = 0; i < cnt; i++)
432					if (outp[i] != 0) {
433						sparse = 0;
434						break;
435					}
436			}
437			if (sparse && !force) {
438				pending += cnt;
439				nw = cnt;
440			} else {
441				if (pending != 0) {
442					if (force)
443						pending--;
444					if (lseek(out.fd, pending, SEEK_CUR) ==
445					    -1)
446						err(2, "%s: seek error creating sparse file",
447						    out.name);
448					if (force)
449						write(out.fd, outp, 1);
450					pending = 0;
451				}
452				if (cnt)
453					nw = write(out.fd, outp, cnt);
454				else
455					return;
456			}
457
458			if (nw <= 0) {
459				if (nw == 0)
460					errx(1, "%s: end of device", out.name);
461				if (errno != EINTR)
462					err(1, "%s", out.name);
463				nw = 0;
464			}
465			outp += nw;
466			st.bytes += nw;
467			if ((size_t)nw == n) {
468				if (n != out.dbsz)
469					++st.out_part;
470				else
471					++st.out_full;
472				break;
473			}
474			++st.out_part;
475			if ((size_t)nw == cnt)
476				break;
477			if (out.flags & ISTAPE)
478				errx(1, "%s: short write on tape device",
479				    out.name);
480			if (out.flags & ISCHR && !warned) {
481				warned = 1;
482				warnx("%s: short write on character device",
483				    out.name);
484			}
485		}
486		if ((out.dbcnt -= n) < out.dbsz)
487			break;
488	}
489
490	/* Reassemble the output block. */
491	if (out.dbcnt)
492		(void)memmove(out.db, out.dbp - out.dbcnt, out.dbcnt);
493	out.dbp = out.db + out.dbcnt;
494}
495