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