1 /* $OpenBSD: dd.c,v 1.29 2024/07/12 14:30:27 deraadt Exp $ */
2 /* $NetBSD: dd.c,v 1.6 1996/02/20 19:29:06 jtc Exp $ */
3
4 /*-
5 * Copyright (c) 1991, 1993, 1994
6 * The Regents of the University of California. All rights reserved.
7 *
8 * This code is derived from software contributed to Berkeley by
9 * Keith Muller of the University of California, San Diego and Lance
10 * Visser of Convex Computer Corporation.
11 *
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
14 * are met:
15 * 1. Redistributions of source code must retain the above copyright
16 * notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 * notice, this list of conditions and the following disclaimer in the
19 * documentation and/or other materials provided with the distribution.
20 * 3. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 */
36
37 #include <sys/types.h>
38 #include <sys/stat.h>
39 #include <sys/ioctl.h>
40 #include <sys/mtio.h>
41
42 #include <ctype.h>
43 #include <err.h>
44 #include <errno.h>
45 #include <fcntl.h>
46 #include <signal.h>
47 #include <stdio.h>
48 #include <stdlib.h>
49 #include <string.h>
50 #include <unistd.h>
51
52 #include "dd.h"
53 #include "extern.h"
54
55 static void dd_close(void);
56 static void dd_in(void);
57 static void getfdtype(IO *);
58 static void setup(void);
59
60 #define MAXIMUM(a, b) (((a) > (b)) ? (a) : (b))
61
62 IO in, out; /* input/output state */
63 STAT st; /* statistics */
64 void (*cfunc)(void); /* conversion function */
65 size_t cpy_cnt; /* # of blocks to copy */
66 u_int ddflags; /* conversion options */
67 size_t cbsz; /* conversion block size */
68 size_t files_cnt = 1; /* # of files to copy */
69 const u_char *ctab; /* conversion table */
70
71 int
main(int argc,char * argv[])72 main(int argc, char *argv[])
73 {
74 jcl(argv);
75 setup();
76
77 (void)signal(SIGINFO, sig_summary);
78 (void)signal(SIGINT, sig_terminate);
79
80 atexit(exit_summary);
81
82 if (cpy_cnt != (size_t)-1) {
83 while (files_cnt--)
84 dd_in();
85 }
86
87 dd_close();
88 exit(0);
89 }
90
91 static void
setup(void)92 setup(void)
93 {
94 if (in.name == NULL) {
95 in.name = "stdin";
96 in.fd = STDIN_FILENO;
97 } else {
98 in.fd = open(in.name, O_RDONLY);
99 if (in.fd == -1)
100 err(1, "%s", in.name);
101 }
102
103 getfdtype(&in);
104
105 if (files_cnt > 1 && !(in.flags & ISTAPE))
106 errx(1, "files is not supported for non-tape devices");
107
108 if (out.name == NULL) {
109 /* No way to check for read access here. */
110 out.fd = STDOUT_FILENO;
111 out.name = "stdout";
112 } else {
113 #define OFLAGS \
114 (O_CREAT | (ddflags & (C_SEEK | C_NOTRUNC) ? 0 : O_TRUNC))
115 out.fd = open(out.name, O_RDWR | OFLAGS, DEFFILEMODE);
116 /*
117 * May not have read access, so try again with write only.
118 * Without read we may have a problem if output also does
119 * not support seeks.
120 */
121 if (out.fd == -1) {
122 out.fd = open(out.name, O_WRONLY | OFLAGS, DEFFILEMODE);
123 out.flags |= NOREAD;
124 }
125 if (out.fd == -1)
126 err(1, "%s", out.name);
127 }
128
129 getfdtype(&out);
130
131 /*
132 * Allocate space for the input and output buffers. If not doing
133 * record oriented I/O, only need a single buffer.
134 */
135 if (!(ddflags & (C_BLOCK|C_UNBLOCK))) {
136 if ((in.db = malloc(out.dbsz + in.dbsz - 1)) == NULL)
137 err(1, "input buffer");
138 out.db = in.db;
139 } else {
140 in.db = malloc(MAXIMUM(in.dbsz, cbsz) + cbsz);
141 if (in.db == NULL)
142 err(1, "input buffer");
143 out.db = malloc(out.dbsz + cbsz);
144 if (out.db == NULL)
145 err(1, "output buffer");
146 }
147 in.dbp = in.db;
148 out.dbp = out.db;
149
150 /* Position the input/output streams. */
151 if (in.offset)
152 pos_in();
153 if (out.offset)
154 pos_out();
155
156 if (pledge("stdio", NULL) == -1)
157 err(1, "pledge");
158
159 /*
160 * Truncate the output file; ignore errors because it fails on some
161 * kinds of output files, tapes, for example.
162 */
163 if ((ddflags & (C_OF | C_SEEK | C_NOTRUNC)) == (C_OF | C_SEEK))
164 (void)ftruncate(out.fd, out.offset * out.dbsz);
165
166 /*
167 * If converting case at the same time as another conversion, build a
168 * table that does both at once. If just converting case, use the
169 * built-in tables.
170 */
171 if (ddflags & (C_LCASE|C_UCASE)) {
172 #ifdef NO_CONV
173 /* Should not get here, but just in case... */
174 errx(1, "case conv and -DNO_CONV");
175 #else /* NO_CONV */
176 u_int cnt;
177 if (ddflags & C_ASCII || ddflags & C_EBCDIC) {
178 if (ddflags & C_LCASE) {
179 for (cnt = 0; cnt < 0377; ++cnt)
180 casetab[cnt] = tolower(ctab[cnt]);
181 } else {
182 for (cnt = 0; cnt < 0377; ++cnt)
183 casetab[cnt] = toupper(ctab[cnt]);
184 }
185 } else {
186 if (ddflags & C_LCASE) {
187 for (cnt = 0; cnt < 0377; ++cnt)
188 casetab[cnt] = tolower(cnt);
189 } else {
190 for (cnt = 0; cnt < 0377; ++cnt)
191 casetab[cnt] = toupper(cnt);
192 }
193 }
194
195 ctab = casetab;
196 #endif /* NO_CONV */
197 }
198
199 /* Statistics timestamp. */
200 clock_gettime(CLOCK_MONOTONIC, &st.start);
201 }
202
203 static void
getfdtype(IO * io)204 getfdtype(IO *io)
205 {
206 struct mtget mt;
207 struct stat sb;
208
209 if (fstat(io->fd, &sb))
210 err(1, "%s", io->name);
211 if (S_ISCHR(sb.st_mode))
212 io->flags |= ioctl(io->fd, MTIOCGET, &mt) ? ISCHR : ISTAPE;
213 if (S_ISFIFO(sb.st_mode) || S_ISSOCK(sb.st_mode))
214 io->flags |= ISPIPE;
215 }
216
217 static void
swapbytes(void * v,size_t len)218 swapbytes(void *v, size_t len)
219 {
220 unsigned char *p = v;
221 unsigned char t;
222
223 while (len > 1) {
224 t = p[0];
225 p[0] = p[1];
226 p[1] = t;
227 p += 2;
228 len -= 2;
229 }
230 }
231
232
233 static void
dd_in(void)234 dd_in(void)
235 {
236 ssize_t n;
237
238 for (;;) {
239 if (cpy_cnt && (st.in_full + st.in_part) >= cpy_cnt)
240 return;
241
242 /*
243 * Zero the buffer first if sync; if doing block operations
244 * use spaces.
245 */
246 if (ddflags & C_SYNC) {
247 if (ddflags & (C_BLOCK|C_UNBLOCK))
248 (void)memset(in.dbp, ' ', in.dbsz);
249 else
250 (void)memset(in.dbp, 0, in.dbsz);
251 }
252
253 n = read(in.fd, in.dbp, in.dbsz);
254 if (n == 0) {
255 in.dbrcnt = 0;
256 return;
257 }
258
259 /* Read error. */
260 if (n == -1) {
261 /*
262 * If noerror not specified, die. POSIX requires that
263 * the warning message be followed by an I/O display.
264 */
265 if (!(ddflags & C_NOERROR))
266 err(1, "%s", in.name);
267 warn("%s", in.name);
268 sig_summary(0);
269
270 /*
271 * If it's not a tape drive or a pipe, seek past the
272 * error. If your OS doesn't do the right thing for
273 * raw disks this section should be modified to re-read
274 * in sector size chunks.
275 */
276 if (!(in.flags & (ISPIPE|ISTAPE)) &&
277 lseek(in.fd, (off_t)in.dbsz, SEEK_CUR))
278 warn("%s", in.name);
279
280 /* If sync not specified, omit block and continue. */
281 if (!(ddflags & C_SYNC))
282 continue;
283
284 /* Read errors count as full blocks. */
285 in.dbcnt += in.dbrcnt = in.dbsz;
286 ++st.in_full;
287
288 /* Handle full input blocks. */
289 } else if (n == in.dbsz) {
290 in.dbcnt += in.dbrcnt = n;
291 ++st.in_full;
292
293 /* Handle partial input blocks. */
294 } else {
295 /* If sync, use the entire block. */
296 if (ddflags & C_SYNC)
297 in.dbcnt += in.dbrcnt = in.dbsz;
298 else
299 in.dbcnt += in.dbrcnt = n;
300 ++st.in_part;
301 }
302
303 /*
304 * POSIX states that if bs is set and no other conversions
305 * than noerror, notrunc or sync are specified, the block
306 * is output without buffering as it is read.
307 */
308 if (ddflags & C_BS) {
309 out.dbcnt = in.dbcnt;
310 dd_out(1);
311 in.dbcnt = 0;
312 continue;
313 }
314
315 if (ddflags & C_SWAB) {
316 if ((n = in.dbrcnt) & 1) {
317 ++st.swab;
318 --n;
319 }
320 swapbytes(in.dbp, n);
321 }
322
323 in.dbp += in.dbrcnt;
324 (*cfunc)();
325 }
326 }
327
328 /*
329 * Cleanup any remaining I/O and flush output. If necessary, output file
330 * is truncated.
331 */
332 static void
dd_close(void)333 dd_close(void)
334 {
335 if (cfunc == def)
336 def_close();
337 else if (cfunc == block)
338 block_close();
339 else if (cfunc == unblock)
340 unblock_close();
341 if (ddflags & C_OSYNC && out.dbcnt && out.dbcnt < out.dbsz) {
342 if (ddflags & (C_BLOCK|C_UNBLOCK))
343 memset(out.dbp, ' ', out.dbsz - out.dbcnt);
344 else
345 memset(out.dbp, 0, out.dbsz - out.dbcnt);
346 out.dbcnt = out.dbsz;
347 }
348 if (out.dbcnt)
349 dd_out(1);
350 if (ddflags & C_FSYNC) {
351 if (fsync(out.fd) == -1)
352 err(1, "fsync %s", out.name);
353 }
354 }
355
356 void
dd_out(int force)357 dd_out(int force)
358 {
359 static int warned;
360 size_t cnt, n;
361 ssize_t nw;
362 u_char *outp;
363
364 /*
365 * Write one or more blocks out. The common case is writing a full
366 * output block in a single write; increment the full block stats.
367 * Otherwise, we're into partial block writes. If a partial write,
368 * and it's a character device, just warn. If a tape device, quit.
369 *
370 * The partial writes represent two cases. 1: Where the input block
371 * was less than expected so the output block was less than expected.
372 * 2: Where the input block was the right size but we were forced to
373 * write the block in multiple chunks. The original versions of dd(1)
374 * never wrote a block in more than a single write, so the latter case
375 * never happened.
376 *
377 * One special case is if we're forced to do the write -- in that case
378 * we play games with the buffer size, and it's usually a partial write.
379 */
380 outp = out.db;
381 for (n = force ? out.dbcnt : out.dbsz;; n = out.dbsz) {
382 for (cnt = n;; cnt -= nw) {
383 nw = write(out.fd, outp, cnt);
384 if (nw == 0)
385 errx(1, "%s: end of device", out.name);
386 if (nw == -1) {
387 if (errno != EINTR)
388 err(1, "%s", out.name);
389 nw = 0;
390 }
391 outp += nw;
392 st.bytes += nw;
393 if (nw == n) {
394 if (n != out.dbsz)
395 ++st.out_part;
396 else
397 ++st.out_full;
398 break;
399 }
400 ++st.out_part;
401 if (nw == cnt)
402 break;
403 if (out.flags & ISCHR && !warned) {
404 warned = 1;
405 warnx("%s: short write on character device",
406 out.name);
407 }
408 if (out.flags & ISTAPE)
409 errx(1, "%s: short write on tape device", out.name);
410 }
411 if ((out.dbcnt -= n) < out.dbsz)
412 break;
413 }
414
415 /* Reassemble the output block. */
416 if (out.dbcnt)
417 (void)memmove(out.db, out.dbp - out.dbcnt, out.dbcnt);
418 out.dbp = out.db + out.dbcnt;
419 }
420