coreutils/dd.c

   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 source tree.
   9  */
  10
  11 //usage:#define dd_trivial_usage
  12 //usage:       "[if=FILE] [of=FILE] " IF_FEATURE_DD_IBS_OBS("[ibs=N] [obs=N] ") "[bs=N] [count=N] [skip=N]\n"
  13 //usage:       "        [seek=N]" IF_FEATURE_DD_IBS_OBS(" [conv=notrunc|noerror|sync|fsync]")
  14 //usage:#define dd_full_usage "\n\n"
  15 //usage:       "Copy a file with converting and formatting\n"
  16 //usage:     "\nOptions:"
  17 //usage:     "\n        if=FILE         Read from FILE instead of stdin"
  18 //usage:     "\n        of=FILE         Write to FILE instead of stdout"
  19 //usage:     "\n        bs=N            Read and write N bytes at a time"
  20 //usage:        IF_FEATURE_DD_IBS_OBS(
  21 //usage:     "\n        ibs=N           Read N bytes at a time"
  22 //usage:        )
  23 //usage:        IF_FEATURE_DD_IBS_OBS(
  24 //usage:     "\n        obs=N           Write N bytes at a time"
  25 //usage:        )
  26 //usage:     "\n        count=N         Copy only N input blocks"
  27 //usage:     "\n        skip=N          Skip N input blocks"
  28 //usage:     "\n        seek=N          Skip N output blocks"
  29 //usage:        IF_FEATURE_DD_IBS_OBS(
  30 //usage:     "\n        conv=notrunc    Don't truncate output file"
  31 //usage:     "\n        conv=noerror    Continue after read errors"
  32 //usage:     "\n        conv=sync       Pad blocks with zeros"
  33 //usage:     "\n        conv=fsync      Physically write data out before finishing"
  34 //usage:        )
  35 //usage:     "\n"
  36 //usage:     "\nNumbers may be suffixed by c (x1), w (x2), b (x512), kD (x1000), k (x1024),"
  37 //usage:     "\nMD (x1000000), M (x1048576), GD (x1000000000) or G (x1073741824)"
  38 //usage:
  39 //usage:#define dd_example_usage
  40 //usage:       "$ dd if=/dev/zero of=/dev/ram1 bs=1M count=4\n"
  41 //usage:       "4+0 records in\n"
  42 //usage:       "4+0 records out\n"
  43
  44 #include "libbb.h"
  45
  46 /* This is a NOEXEC applet. Be very careful! */
  47
  48
  49 enum {
  50         ifd = STDIN_FILENO,
  51         ofd = STDOUT_FILENO,
  52 };
  53
  54 static const struct suffix_mult dd_suffixes[] = {
  55         { "c", 1 },
  56         { "w", 2 },
  57         { "b", 512 },
  58         { "kD", 1000 },
  59         { "k", 1024 },
  60         { "K", 1024 },  /* compat with coreutils dd */
  61         { "MD", 1000000 },
  62         { "M", 1048576 },
  63         { "GD", 1000000000 },
  64         { "G", 1073741824 },
  65         { "", 0 }
  66 };
  67
  68 struct globals {
  69         off_t out_full, out_part, in_full, in_part;
  70 #if ENABLE_FEATURE_DD_THIRD_STATUS_LINE
  71         unsigned long long total_bytes;
  72         unsigned long long begin_time_us;
  73 #endif
  74 } FIX_ALIASING;
  75 #define G (*(struct globals*)&bb_common_bufsiz1)
  76 #define INIT_G() do { \
  77         /* we have to zero it out because of NOEXEC */ \
  78         memset(&G, 0, sizeof(G)); \
  79 } while (0)
  80
  81
  82 static void dd_output_status(int UNUSED_PARAM cur_signal)
  83 {
  84 #if ENABLE_FEATURE_DD_THIRD_STATUS_LINE
  85         double seconds;
  86         unsigned long long bytes_sec;
  87         unsigned long long now_us = monotonic_us(); /* before fprintf */
  88 #endif
  89
  90         /* Deliberately using %u, not %d */
  91         fprintf(stderr, "%"OFF_FMT"u+%"OFF_FMT"u records in\n"
  92                         "%"OFF_FMT"u+%"OFF_FMT"u records out\n",
  93                         G.in_full, G.in_part,
  94                         G.out_full, G.out_part);
  95
  96 #if ENABLE_FEATURE_DD_THIRD_STATUS_LINE
  97         fprintf(stderr, "%llu bytes (%sB) copied, ",
  98                         G.total_bytes,
  99                         /* show fractional digit, use suffixes */
 100                         make_human_readable_str(G.total_bytes, 1, 0)
 101         );
 102         /* Corner cases:
 103          * ./busybox dd </dev/null >/dev/null
 104          * ./busybox dd bs=1M count=2000 </dev/zero >/dev/null
 105          * (echo DONE) | ./busybox dd >/dev/null
 106          * (sleep 1; echo DONE) | ./busybox dd >/dev/null
 107          */
 108         seconds = (now_us - G.begin_time_us) / 1000000.0;
 109         bytes_sec = G.total_bytes / seconds;
 110         fprintf(stderr, "%f seconds, %sB/s\n",
 111                         seconds,
 112                         /* show fractional digit, use suffixes */
 113                         make_human_readable_str(bytes_sec, 1, 0)
 114         );
 115 #endif
 116 }
 117
 118 static ssize_t full_write_or_warn(const void *buf, size_t len,
 119         const char *const filename)
 120 {
 121         ssize_t n = full_write(ofd, buf, len);
 122         if (n < 0)
 123                 bb_perror_msg("writing '%s'", filename);
 124         return n;
 125 }
 126
 127 static bool write_and_stats(const void *buf, size_t len, size_t obs,
 128         const char *filename)
 129 {
 130         ssize_t n = full_write_or_warn(buf, len, filename);
 131         if (n < 0)
 132                 return 1;
 133         if ((size_t)n == obs)
 134                 G.out_full++;
 135         else if (n) /* > 0 */
 136                 G.out_part++;
 137 #if ENABLE_FEATURE_DD_THIRD_STATUS_LINE
 138         G.total_bytes += n;
 139 #endif
 140         return 0;
 141 }
 142
 143 #if ENABLE_LFS
 144 # define XATOU_SFX xatoull_sfx
 145 #else
 146 # define XATOU_SFX xatoul_sfx
 147 #endif
 148
 149 int dd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 150 int dd_main(int argc UNUSED_PARAM, char **argv)
 151 {
 152         enum {
 153                 /* Must be in the same order as OP_conv_XXX! */
 154                 /* (see "flags |= (1 << what)" below) */
 155                 FLAG_NOTRUNC = 1 << 0,
 156                 FLAG_SYNC    = 1 << 1,
 157                 FLAG_NOERROR = 1 << 2,
 158                 FLAG_FSYNC   = 1 << 3,
 159                 /* end of conv flags */
 160                 FLAG_TWOBUFS = 1 << 4,
 161                 FLAG_COUNT   = 1 << 5,
 162         };
 163         static const char keywords[] ALIGN1 =
 164                 "bs\0""count\0""seek\0""skip\0""if\0""of\0"
 165 #if ENABLE_FEATURE_DD_IBS_OBS
 166                 "ibs\0""obs\0""conv\0"
 167 #endif
 168                 ;
 169 #if ENABLE_FEATURE_DD_IBS_OBS
 170         static const char conv_words[] ALIGN1 =
 171                 "notrunc\0""sync\0""noerror\0""fsync\0";
 172 #endif
 173         enum {
 174                 OP_bs = 0,
 175                 OP_count,
 176                 OP_seek,
 177                 OP_skip,
 178                 OP_if,
 179                 OP_of,
 180 #if ENABLE_FEATURE_DD_IBS_OBS
 181                 OP_ibs,
 182                 OP_obs,
 183                 OP_conv,
 184                 /* Must be in the same order as FLAG_XXX! */
 185                 OP_conv_notrunc = 0,
 186                 OP_conv_sync,
 187                 OP_conv_noerror,
 188                 OP_conv_fsync,
 189         /* Unimplemented conv=XXX: */
 190         //nocreat       do not create the output file
 191         //excl          fail if the output file already exists
 192         //fdatasync     physically write output file data before finishing
 193         //swab          swap every pair of input bytes
 194         //lcase         change upper case to lower case
 195         //ucase         change lower case to upper case
 196         //block         pad newline-terminated records with spaces to cbs-size
 197         //unblock       replace trailing spaces in cbs-size records with newline
 198         //ascii         from EBCDIC to ASCII
 199         //ebcdic        from ASCII to EBCDIC
 200         //ibm           from ASCII to alternate EBCDIC
 201 #endif
 202         };
 203         int exitcode = EXIT_FAILURE;
 204         size_t ibs = 512, obs = 512;
 205         ssize_t n, w;
 206         char *ibuf, *obuf;
 207         /* And these are all zeroed at once! */
 208         struct {
 209                 int flags;
 210                 size_t oc;
 211                 off_t count;
 212                 off_t seek, skip;
 213                 const char *infile, *outfile;
 214         } Z;
 215 #define flags   (Z.flags  )
 216 #define oc      (Z.oc     )
 217 #define count   (Z.count  )
 218 #define seek    (Z.seek   )
 219 #define skip    (Z.skip   )
 220 #define infile  (Z.infile )
 221 #define outfile (Z.outfile)
 222
 223         memset(&Z, 0, sizeof(Z));
 224         INIT_G();
 225         //fflush_all(); - is this needed because of NOEXEC?
 226
 227         for (n = 1; argv[n]; n++) {
 228                 int what;
 229                 char *val;
 230                 char *arg = argv[n];
 231
 232 #if ENABLE_DESKTOP
 233                 /* "dd --". NB: coreutils 6.9 will complain if they see
 234                  * more than one of them. We wouldn't. */
 235                 if (arg[0] == '-' && arg[1] == '-' && arg[2] == '\0')
 236                         continue;
 237 #endif
 238                 val = strchr(arg, '=');
 239                 if (val == NULL)
 240                         bb_show_usage();
 241                 *val = '\0';
 242                 what = index_in_strings(keywords, arg);
 243                 if (what < 0)
 244                         bb_show_usage();
 245                 /* *val = '='; - to preserve ps listing? */
 246                 val++;
 247 #if ENABLE_FEATURE_DD_IBS_OBS
 248                 if (what == OP_ibs) {
 249                         /* Must fit into positive ssize_t */
 250                         ibs = xatoul_range_sfx(val, 1, ((size_t)-1L)/2, dd_suffixes);
 251                         /*continue;*/
 252                 }
 253                 if (what == OP_obs) {
 254                         obs = xatoul_range_sfx(val, 1, ((size_t)-1L)/2, dd_suffixes);
 255                         /*continue;*/
 256                 }
 257                 if (what == OP_conv) {
 258                         while (1) {
 259                                 /* find ',', replace them with NUL so we can use val for
 260                                  * index_in_strings() without copying.
 261                                  * We rely on val being non-null, else strchr would fault.
 262                                  */
 263                                 arg = strchr(val, ',');
 264                                 if (arg)
 265                                         *arg = '\0';
 266                                 what = index_in_strings(conv_words, val);
 267                                 if (what < 0)
 268                                         bb_error_msg_and_die(bb_msg_invalid_arg, val, "conv");
 269                                 flags |= (1 << what);
 270                                 if (!arg) /* no ',' left, so this was the last specifier */
 271                                         break;
 272                                 /* *arg = ','; - to preserve ps listing? */
 273                                 val = arg + 1; /* skip this keyword and ',' */
 274                         }
 275                         continue; /* we trashed 'what', can't fall through */
 276                 }
 277 #endif
 278                 if (what == OP_bs) {
 279                         ibs = obs = xatoul_range_sfx(val, 1, ((size_t)-1L)/2, dd_suffixes);
 280                         /*continue;*/
 281                 }
 282                 /* These can be large: */
 283                 if (what == OP_count) {
 284                         flags |= FLAG_COUNT;
 285                         count = XATOU_SFX(val, dd_suffixes);
 286                         /*continue;*/
 287                 }
 288                 if (what == OP_seek) {
 289                         seek = XATOU_SFX(val, dd_suffixes);
 290                         /*continue;*/
 291                 }
 292                 if (what == OP_skip) {
 293                         skip = XATOU_SFX(val, dd_suffixes);
 294                         /*continue;*/
 295                 }
 296                 if (what == OP_if) {
 297                         infile = val;
 298                         /*continue;*/
 299                 }
 300                 if (what == OP_of) {
 301                         outfile = val;
 302                         /*continue;*/
 303                 }
 304         } /* end of "for (argv[n])" */
 305
 306 //XXX:FIXME for huge ibs or obs, malloc'ing them isn't the brightest idea ever
 307         ibuf = obuf = xmalloc(ibs);
 308         if (ibs != obs) {
 309                 flags |= FLAG_TWOBUFS;
 310                 obuf = xmalloc(obs);
 311         }
 312
 313 #if ENABLE_FEATURE_DD_SIGNAL_HANDLING
 314         signal_SA_RESTART_empty_mask(SIGUSR1, dd_output_status);
 315 #endif
 316 #if ENABLE_FEATURE_DD_THIRD_STATUS_LINE
 317         G.begin_time_us = monotonic_us();
 318 #endif
 319
 320         if (infile != NULL)
 321                 xmove_fd(xopen(infile, O_RDONLY), ifd);
 322         else {
 323                 infile = bb_msg_standard_input;
 324         }
 325         if (outfile != NULL) {
 326                 int oflag = O_WRONLY | O_CREAT;
 327
 328                 if (!seek && !(flags & FLAG_NOTRUNC))
 329                         oflag |= O_TRUNC;
 330
 331                 xmove_fd(xopen(outfile, oflag), ofd);
 332
 333                 if (seek && !(flags & FLAG_NOTRUNC)) {
 334                         if (ftruncate(ofd, seek * obs) < 0) {
 335                                 struct stat st;
 336
 337                                 if (fstat(ofd, &st) < 0
 338                                  || S_ISREG(st.st_mode)
 339                                  || S_ISDIR(st.st_mode)
 340                                 ) {
 341                                         goto die_outfile;
 342                                 }
 343                         }
 344                 }
 345         } else {
 346                 outfile = bb_msg_standard_output;
 347         }
 348         if (skip) {
 349                 if (lseek(ifd, skip * ibs, SEEK_CUR) < 0) {
 350                         while (skip-- > 0) {
 351                                 n = safe_read(ifd, ibuf, ibs);
 352                                 if (n < 0)
 353                                         goto die_infile;
 354                                 if (n == 0)
 355                                         break;
 356                         }
 357                 }
 358         }
 359         if (seek) {
 360                 if (lseek(ofd, seek * obs, SEEK_CUR) < 0)
 361                         goto die_outfile;
 362         }
 363
 364         while (!(flags & FLAG_COUNT) || (G.in_full + G.in_part != count)) {
 365                 n = safe_read(ifd, ibuf, ibs);
 366                 if (n == 0)
 367                         break;
 368                 if (n < 0) {
 369                         /* "Bad block" */
 370                         if (!(flags & FLAG_NOERROR))
 371                                 goto die_infile;
 372                         bb_simple_perror_msg(infile);
 373                         /* GNU dd with conv=noerror skips over bad blocks */
 374                         xlseek(ifd, ibs, SEEK_CUR);
 375                         /* conv=noerror,sync writes NULs,
 376                          * conv=noerror just ignores input bad blocks */
 377                         n = 0;
 378                 }
 379                 if ((size_t)n == ibs)
 380                         G.in_full++;
 381                 else {
 382                         G.in_part++;
 383                         if (flags & FLAG_SYNC) {
 384                                 memset(ibuf + n, 0, ibs - n);
 385                                 n = ibs;
 386                         }
 387                 }
 388                 if (flags & FLAG_TWOBUFS) {
 389                         char *tmp = ibuf;
 390                         while (n) {
 391                                 size_t d = obs - oc;
 392
 393                                 if (d > (size_t)n)
 394                                         d = n;
 395                                 memcpy(obuf + oc, tmp, d);
 396                                 n -= d;
 397                                 tmp += d;
 398                                 oc += d;
 399                                 if (oc == obs) {
 400                                         if (write_and_stats(obuf, obs, obs, outfile))
 401                                                 goto out_status;
 402                                         oc = 0;
 403                                 }
 404                         }
 405                 } else if (write_and_stats(ibuf, n, obs, outfile))
 406                         goto out_status;
 407
 408                 if (flags & FLAG_FSYNC) {
 409                         if (fsync(ofd) < 0)
 410                                 goto die_outfile;
 411                 }
 412         }
 413
 414         if (ENABLE_FEATURE_DD_IBS_OBS && oc) {
 415                 w = full_write_or_warn(obuf, oc, outfile);
 416                 if (w < 0) goto out_status;
 417                 if (w > 0) G.out_part++;
 418         }
 419         if (close(ifd) < 0) {
 420  die_infile:
 421                 bb_simple_perror_msg_and_die(infile);
 422         }
 423
 424         if (close(ofd) < 0) {
 425  die_outfile:
 426                 bb_simple_perror_msg_and_die(outfile);
 427         }
 428
 429         exitcode = EXIT_SUCCESS;
 430  out_status:
 431         dd_output_status(0);
 432
 433         if (ENABLE_FEATURE_CLEAN_UP) {
 434                 free(obuf);
 435                 if (flags & FLAG_TWOBUFS)
 436                         free(ibuf);
 437         }
 438
 439         return exitcode;
 440 }