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 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 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 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 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 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 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 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