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