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