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