xref: /freebsd/bin/dd/dd.c (revision 41059135ce931c0f1014a999ffabc6bc470ce856)
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  * 3. 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
36 static 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
42 static char sccsid[] = "@(#)dd.c	8.5 (Berkeley) 4/2/94";
43 #endif /* not lint */
44 #endif
45 #include <sys/cdefs.h>
46 __FBSDID("$FreeBSD$");
47 
48 #include <sys/param.h>
49 #include <sys/stat.h>
50 #include <sys/capsicum.h>
51 #include <sys/conf.h>
52 #include <sys/disklabel.h>
53 #include <sys/filio.h>
54 #include <sys/mtio.h>
55 
56 #include <assert.h>
57 #include <capsicum_helpers.h>
58 #include <ctype.h>
59 #include <err.h>
60 #include <errno.h>
61 #include <fcntl.h>
62 #include <inttypes.h>
63 #include <locale.h>
64 #include <stdio.h>
65 #include <stdlib.h>
66 #include <string.h>
67 #include <time.h>
68 #include <unistd.h>
69 
70 #include "dd.h"
71 #include "extern.h"
72 
73 static void dd_close(void);
74 static void dd_in(void);
75 static void getfdtype(IO *);
76 static void setup(void);
77 
78 IO	in, out;		/* input/output state */
79 STAT	st;			/* statistics */
80 void	(*cfunc)(void);		/* conversion function */
81 uintmax_t cpy_cnt;		/* # of blocks to copy */
82 static off_t	pending = 0;	/* pending seek if sparse */
83 u_int	ddflags = 0;		/* conversion options */
84 size_t	cbsz;			/* conversion block size */
85 uintmax_t files_cnt = 1;	/* # of files to copy */
86 const	u_char *ctab;		/* conversion table */
87 char	fill_char;		/* Character to fill with if defined */
88 size_t	speed = 0;		/* maximum speed, in bytes per second */
89 volatile sig_atomic_t need_summary;
90 
91 int
92 main(int argc __unused, char *argv[])
93 {
94 	(void)setlocale(LC_CTYPE, "");
95 	jcl(argv);
96 	setup();
97 
98 	caph_cache_catpages();
99 	if (cap_enter() == -1 && errno != ENOSYS)
100 		err(1, "unable to enter capability mode");
101 
102 	(void)signal(SIGINFO, siginfo_handler);
103 	(void)signal(SIGINT, terminate);
104 
105 	atexit(summary);
106 
107 	while (files_cnt--)
108 		dd_in();
109 
110 	dd_close();
111 	/*
112 	 * Some devices such as cfi(4) may perform significant amounts
113 	 * of work when a write descriptor is closed.  Close the out
114 	 * descriptor explicitly so that the summary handler (called
115 	 * from an atexit() hook) includes this work.
116 	 */
117 	close(out.fd);
118 	exit(0);
119 }
120 
121 static int
122 parity(u_char c)
123 {
124 	int i;
125 
126 	i = c ^ (c >> 1) ^ (c >> 2) ^ (c >> 3) ^
127 	    (c >> 4) ^ (c >> 5) ^ (c >> 6) ^ (c >> 7);
128 	return (i & 1);
129 }
130 
131 static void
132 setup(void)
133 {
134 	u_int cnt;
135 	cap_rights_t rights;
136 	unsigned long cmds[] = { FIODTYPE, MTIOCTOP };
137 
138 	if (in.name == NULL) {
139 		in.name = "stdin";
140 		in.fd = STDIN_FILENO;
141 	} else {
142 		in.fd = open(in.name, O_RDONLY, 0);
143 		if (in.fd == -1)
144 			err(1, "%s", in.name);
145 	}
146 
147 	getfdtype(&in);
148 
149 	cap_rights_init(&rights, CAP_READ, CAP_SEEK);
150 	if (cap_rights_limit(in.fd, &rights) == -1 && errno != ENOSYS)
151 		err(1, "unable to limit capability rights");
152 
153 	if (files_cnt > 1 && !(in.flags & ISTAPE))
154 		errx(1, "files is not supported for non-tape devices");
155 
156 	cap_rights_set(&rights, CAP_FTRUNCATE, CAP_IOCTL, CAP_WRITE);
157 	if (out.name == NULL) {
158 		/* No way to check for read access here. */
159 		out.fd = STDOUT_FILENO;
160 		out.name = "stdout";
161 	} else {
162 #define	OFLAGS \
163     (O_CREAT | (ddflags & (C_SEEK | C_NOTRUNC) ? 0 : O_TRUNC))
164 		out.fd = open(out.name, O_RDWR | OFLAGS, DEFFILEMODE);
165 		/*
166 		 * May not have read access, so try again with write only.
167 		 * Without read we may have a problem if output also does
168 		 * not support seeks.
169 		 */
170 		if (out.fd == -1) {
171 			out.fd = open(out.name, O_WRONLY | OFLAGS, DEFFILEMODE);
172 			out.flags |= NOREAD;
173 			cap_rights_clear(&rights, CAP_READ);
174 		}
175 		if (out.fd == -1)
176 			err(1, "%s", out.name);
177 	}
178 
179 	getfdtype(&out);
180 
181 	if (cap_rights_limit(out.fd, &rights) == -1 && errno != ENOSYS)
182 		err(1, "unable to limit capability rights");
183 	if (cap_ioctls_limit(out.fd, cmds, nitems(cmds)) == -1 &&
184 	    errno != ENOSYS)
185 		err(1, "unable to limit capability rights");
186 
187 	if (in.fd != STDIN_FILENO && out.fd != STDIN_FILENO) {
188 		if (caph_limit_stdin() == -1)
189 			err(1, "unable to limit capability rights");
190 	}
191 
192 	if (in.fd != STDOUT_FILENO && out.fd != STDOUT_FILENO) {
193 		if (caph_limit_stdout() == -1)
194 			err(1, "unable to limit capability rights");
195 	}
196 
197 	if (in.fd != STDERR_FILENO && out.fd != STDERR_FILENO) {
198 		if (caph_limit_stderr() == -1)
199 			err(1, "unable to limit capability rights");
200 	}
201 
202 	/*
203 	 * Allocate space for the input and output buffers.  If not doing
204 	 * record oriented I/O, only need a single buffer.
205 	 */
206 	if (!(ddflags & (C_BLOCK | C_UNBLOCK))) {
207 		if ((in.db = malloc(out.dbsz + in.dbsz - 1)) == NULL)
208 			err(1, "input buffer");
209 		out.db = in.db;
210 	} else if ((in.db = malloc(MAX(in.dbsz, cbsz) + cbsz)) == NULL ||
211 	    (out.db = malloc(out.dbsz + cbsz)) == NULL)
212 		err(1, "output buffer");
213 
214 	/* dbp is the first free position in each buffer. */
215 	in.dbp = in.db;
216 	out.dbp = out.db;
217 
218 	/* Position the input/output streams. */
219 	if (in.offset)
220 		pos_in();
221 	if (out.offset)
222 		pos_out();
223 
224 	/*
225 	 * Truncate the output file.  If it fails on a type of output file
226 	 * that it should _not_ fail on, error out.
227 	 */
228 	if ((ddflags & (C_OF | C_SEEK | C_NOTRUNC)) == (C_OF | C_SEEK) &&
229 	    out.flags & ISTRUNC)
230 		if (ftruncate(out.fd, out.offset * out.dbsz) == -1)
231 			err(1, "truncating %s", out.name);
232 
233 	if (ddflags & (C_LCASE  | C_UCASE | C_ASCII | C_EBCDIC | C_PARITY)) {
234 		if (ctab != NULL) {
235 			for (cnt = 0; cnt <= 0377; ++cnt)
236 				casetab[cnt] = ctab[cnt];
237 		} else {
238 			for (cnt = 0; cnt <= 0377; ++cnt)
239 				casetab[cnt] = cnt;
240 		}
241 		if ((ddflags & C_PARITY) && !(ddflags & C_ASCII)) {
242 			/*
243 			 * If the input is not EBCDIC, and we do parity
244 			 * processing, strip input parity.
245 			 */
246 			for (cnt = 200; cnt <= 0377; ++cnt)
247 				casetab[cnt] = casetab[cnt & 0x7f];
248 		}
249 		if (ddflags & C_LCASE) {
250 			for (cnt = 0; cnt <= 0377; ++cnt)
251 				casetab[cnt] = tolower(casetab[cnt]);
252 		} else if (ddflags & C_UCASE) {
253 			for (cnt = 0; cnt <= 0377; ++cnt)
254 				casetab[cnt] = toupper(casetab[cnt]);
255 		}
256 		if ((ddflags & C_PARITY)) {
257 			/*
258 			 * This should strictly speaking be a no-op, but I
259 			 * wonder what funny LANG settings could get us.
260 			 */
261 			for (cnt = 0; cnt <= 0377; ++cnt)
262 				casetab[cnt] = casetab[cnt] & 0x7f;
263 		}
264 		if ((ddflags & C_PARSET)) {
265 			for (cnt = 0; cnt <= 0377; ++cnt)
266 				casetab[cnt] = casetab[cnt] | 0x80;
267 		}
268 		if ((ddflags & C_PAREVEN)) {
269 			for (cnt = 0; cnt <= 0377; ++cnt)
270 				if (parity(casetab[cnt]))
271 					casetab[cnt] = casetab[cnt] | 0x80;
272 		}
273 		if ((ddflags & C_PARODD)) {
274 			for (cnt = 0; cnt <= 0377; ++cnt)
275 				if (!parity(casetab[cnt]))
276 					casetab[cnt] = casetab[cnt] | 0x80;
277 		}
278 
279 		ctab = casetab;
280 	}
281 
282 	if (clock_gettime(CLOCK_MONOTONIC, &st.start))
283 		err(1, "clock_gettime");
284 }
285 
286 static void
287 getfdtype(IO *io)
288 {
289 	struct stat sb;
290 	int type;
291 
292 	if (fstat(io->fd, &sb) == -1)
293 		err(1, "%s", io->name);
294 	if (S_ISREG(sb.st_mode))
295 		io->flags |= ISTRUNC;
296 	if (S_ISCHR(sb.st_mode) || S_ISBLK(sb.st_mode)) {
297 		if (ioctl(io->fd, FIODTYPE, &type) == -1) {
298 			err(1, "%s", io->name);
299 		} else {
300 			if (type & D_TAPE)
301 				io->flags |= ISTAPE;
302 			else if (type & (D_DISK | D_MEM))
303 				io->flags |= ISSEEK;
304 			if (S_ISCHR(sb.st_mode) && (type & D_TAPE) == 0)
305 				io->flags |= ISCHR;
306 		}
307 		return;
308 	}
309 	errno = 0;
310 	if (lseek(io->fd, (off_t)0, SEEK_CUR) == -1 && errno == ESPIPE)
311 		io->flags |= ISPIPE;
312 	else
313 		io->flags |= ISSEEK;
314 }
315 
316 /*
317  * Limit the speed by adding a delay before every block read.
318  * The delay (t_usleep) is equal to the time computed from block
319  * size and the specified speed limit (t_target) minus the time
320  * spent on actual read and write operations (t_io).
321  */
322 static void
323 speed_limit(void)
324 {
325 	static double t_prev, t_usleep;
326 	double t_now, t_io, t_target;
327 
328 	t_now = secs_elapsed();
329 	t_io = t_now - t_prev - t_usleep;
330 	t_target = (double)in.dbsz / (double)speed;
331 	t_usleep = t_target - t_io;
332 	if (t_usleep > 0)
333 		usleep(t_usleep * 1000000);
334 	else
335 		t_usleep = 0;
336 	t_prev = t_now;
337 }
338 
339 static void
340 dd_in(void)
341 {
342 	ssize_t n;
343 
344 	for (;;) {
345 		switch (cpy_cnt) {
346 		case -1:			/* count=0 was specified */
347 			return;
348 		case 0:
349 			break;
350 		default:
351 			if (st.in_full + st.in_part >= (uintmax_t)cpy_cnt)
352 				return;
353 			break;
354 		}
355 
356 		if (speed > 0)
357 			speed_limit();
358 
359 		/*
360 		 * Zero the buffer first if sync; if doing block operations,
361 		 * use spaces.
362 		 */
363 		if (ddflags & C_SYNC) {
364 			if (ddflags & C_FILL)
365 				memset(in.dbp, fill_char, in.dbsz);
366 			else if (ddflags & (C_BLOCK | C_UNBLOCK))
367 				memset(in.dbp, ' ', in.dbsz);
368 			else
369 				memset(in.dbp, 0, in.dbsz);
370 		}
371 
372 		n = read(in.fd, in.dbp, in.dbsz);
373 		if (n == 0) {
374 			in.dbrcnt = 0;
375 			return;
376 		}
377 
378 		/* Read error. */
379 		if (n == -1) {
380 			/*
381 			 * If noerror not specified, die.  POSIX requires that
382 			 * the warning message be followed by an I/O display.
383 			 */
384 			if (!(ddflags & C_NOERROR))
385 				err(1, "%s", in.name);
386 			warn("%s", in.name);
387 			summary();
388 
389 			/*
390 			 * If it's a seekable file descriptor, seek past the
391 			 * error.  If your OS doesn't do the right thing for
392 			 * raw disks this section should be modified to re-read
393 			 * in sector size chunks.
394 			 */
395 			if (in.flags & ISSEEK &&
396 			    lseek(in.fd, (off_t)in.dbsz, SEEK_CUR))
397 				warn("%s", in.name);
398 
399 			/* If sync not specified, omit block and continue. */
400 			if (!(ddflags & C_SYNC))
401 				continue;
402 
403 			/* Read errors count as full blocks. */
404 			in.dbcnt += in.dbrcnt = in.dbsz;
405 			++st.in_full;
406 
407 		/* Handle full input blocks. */
408 		} else if ((size_t)n == in.dbsz) {
409 			in.dbcnt += in.dbrcnt = n;
410 			++st.in_full;
411 
412 		/* Handle partial input blocks. */
413 		} else {
414 			/* If sync, use the entire block. */
415 			if (ddflags & C_SYNC)
416 				in.dbcnt += in.dbrcnt = in.dbsz;
417 			else
418 				in.dbcnt += in.dbrcnt = n;
419 			++st.in_part;
420 		}
421 
422 		/*
423 		 * POSIX states that if bs is set and no other conversions
424 		 * than noerror, notrunc or sync are specified, the block
425 		 * is output without buffering as it is read.
426 		 */
427 		if ((ddflags & ~(C_NOERROR | C_NOTRUNC | C_SYNC)) == C_BS) {
428 			out.dbcnt = in.dbcnt;
429 			dd_out(1);
430 			in.dbcnt = 0;
431 			continue;
432 		}
433 
434 		if (ddflags & C_SWAB) {
435 			if ((n = in.dbrcnt) & 1) {
436 				++st.swab;
437 				--n;
438 			}
439 			swab(in.dbp, in.dbp, (size_t)n);
440 		}
441 
442 		in.dbp += in.dbrcnt;
443 		(*cfunc)();
444 		if (need_summary) {
445 			summary();
446 		}
447 	}
448 }
449 
450 /*
451  * Clean up any remaining I/O and flush output.  If necessary, the output file
452  * is truncated.
453  */
454 static void
455 dd_close(void)
456 {
457 	if (cfunc == def)
458 		def_close();
459 	else if (cfunc == block)
460 		block_close();
461 	else if (cfunc == unblock)
462 		unblock_close();
463 	if (ddflags & C_OSYNC && out.dbcnt && out.dbcnt < out.dbsz) {
464 		if (ddflags & C_FILL)
465 			memset(out.dbp, fill_char, out.dbsz - out.dbcnt);
466 		else if (ddflags & (C_BLOCK | C_UNBLOCK))
467 			memset(out.dbp, ' ', out.dbsz - out.dbcnt);
468 		else
469 			memset(out.dbp, 0, out.dbsz - out.dbcnt);
470 		out.dbcnt = out.dbsz;
471 	}
472 	if (out.dbcnt || pending)
473 		dd_out(1);
474 
475 	/*
476 	 * If the file ends with a hole, ftruncate it to extend its size
477 	 * up to the end of the hole (without having to write any data).
478 	 */
479 	if (out.seek_offset > 0 && (out.flags & ISTRUNC)) {
480 		if (ftruncate(out.fd, out.seek_offset) == -1)
481 			err(1, "truncating %s", out.name);
482 	}
483 }
484 
485 void
486 dd_out(int force)
487 {
488 	u_char *outp;
489 	size_t cnt, i, n;
490 	ssize_t nw;
491 	static int warned;
492 	int sparse;
493 
494 	/*
495 	 * Write one or more blocks out.  The common case is writing a full
496 	 * output block in a single write; increment the full block stats.
497 	 * Otherwise, we're into partial block writes.  If a partial write,
498 	 * and it's a character device, just warn.  If a tape device, quit.
499 	 *
500 	 * The partial writes represent two cases.  1: Where the input block
501 	 * was less than expected so the output block was less than expected.
502 	 * 2: Where the input block was the right size but we were forced to
503 	 * write the block in multiple chunks.  The original versions of dd(1)
504 	 * never wrote a block in more than a single write, so the latter case
505 	 * never happened.
506 	 *
507 	 * One special case is if we're forced to do the write -- in that case
508 	 * we play games with the buffer size, and it's usually a partial write.
509 	 */
510 	outp = out.db;
511 
512 	/*
513 	 * If force, first try to write all pending data, else try to write
514 	 * just one block. Subsequently always write data one full block at
515 	 * a time at most.
516 	 */
517 	for (n = force ? out.dbcnt : out.dbsz;; n = out.dbsz) {
518 		cnt = n;
519 		do {
520 			sparse = 0;
521 			if (ddflags & C_SPARSE) {
522 				sparse = 1;	/* Is buffer sparse? */
523 				for (i = 0; i < cnt; i++)
524 					if (outp[i] != 0) {
525 						sparse = 0;
526 						break;
527 					}
528 			}
529 			if (sparse && !force) {
530 				pending += cnt;
531 				nw = cnt;
532 			} else {
533 				if (pending != 0) {
534 					/*
535 					 * Seek past hole.  Note that we need to record the
536 					 * reached offset, because we might have no more data
537 					 * to write, in which case we'll need to call
538 					 * ftruncate to extend the file size.
539 					 */
540 					out.seek_offset = lseek(out.fd, pending, SEEK_CUR);
541 					if (out.seek_offset == -1)
542 						err(2, "%s: seek error creating sparse file",
543 						    out.name);
544 					pending = 0;
545 				}
546 				if (cnt) {
547 					nw = write(out.fd, outp, cnt);
548 					out.seek_offset = 0;
549 				} else {
550 					return;
551 				}
552 			}
553 
554 			if (nw <= 0) {
555 				if (nw == 0)
556 					errx(1, "%s: end of device", out.name);
557 				if (errno != EINTR)
558 					err(1, "%s", out.name);
559 				nw = 0;
560 			}
561 
562 			outp += nw;
563 			st.bytes += nw;
564 
565 			if ((size_t)nw == n && n == out.dbsz)
566 				++st.out_full;
567 			else
568 				++st.out_part;
569 
570 			if ((size_t) nw != cnt) {
571 				if (out.flags & ISTAPE)
572 					errx(1, "%s: short write on tape device",
573 				    	out.name);
574 				if (out.flags & ISCHR && !warned) {
575 					warned = 1;
576 					warnx("%s: short write on character device",
577 				    	out.name);
578 				}
579 			}
580 
581 			cnt -= nw;
582 		} while (cnt != 0);
583 
584 		if ((out.dbcnt -= n) < out.dbsz)
585 			break;
586 	}
587 
588 	/* Reassemble the output block. */
589 	if (out.dbcnt)
590 		(void)memmove(out.db, out.dbp - out.dbcnt, out.dbcnt);
591 	out.dbp = out.db + out.dbcnt;
592 }
593