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 <signal.h>  /* For FEATURE_DD_SIGNAL_HANDLING */
  12 #include "libbb.h"
  13
  14 /* This is a NOEXEC applet. Be very careful! */
  15
  16
  17 enum {
  18         ifd = STDIN_FILENO,
  19         ofd = STDOUT_FILENO,
  20 };
  21
  22 static const struct suffix_mult dd_suffixes[] = {
  23         { "c", 1 },
  24         { "w", 2 },
  25         { "b", 512 },
  26         { "kD", 1000 },
  27         { "k", 1024 },
  28         { "K", 1024 },  /* compat with coreutils dd */
  29         { "MD", 1000000 },
  30         { "M", 1048576 },
  31         { "GD", 1000000000 },
  32         { "G", 1073741824 },
  33         { }
  34 };
  35
  36 struct globals {
  37         off_t out_full, out_part, in_full, in_part;
  38 };
  39 #define G (*(struct globals*)&bb_common_bufsiz1)
  40 /* We have to zero it out because of NOEXEC */
  41 #define INIT_G() memset(&G, 0, sizeof(G))
  42
  43
  44 static void dd_output_status(int ATTRIBUTE_UNUSED cur_signal)
  45 {
  46         /* Deliberately using %u, not %d */
  47         fprintf(stderr, "%"OFF_FMT"u+%"OFF_FMT"u records in\n"
  48                         "%"OFF_FMT"u+%"OFF_FMT"u records out\n",
  49                         G.in_full, G.in_part,
  50                         G.out_full, G.out_part);
  51 }
  52
  53 static ssize_t full_write_or_warn(const void *buf, size_t len,
  54         const char *const filename)
  55 {
  56         ssize_t n = full_write(ofd, buf, len);
  57         if (n < 0)
  58                 bb_perror_msg("writing '%s'", filename);
  59         return n;
  60 }
  61
  62 static bool write_and_stats(const void *buf, size_t len, size_t obs,
  63         const char *filename)
  64 {
  65         ssize_t n = full_write_or_warn(buf, len, filename);
  66         if (n < 0)
  67                 return 1;
  68         if (n == obs)
  69                 G.out_full++;
  70         else if (n) /* > 0 */
  71                 G.out_part++;
  72         return 0;
  73 }
  74
  75 #if ENABLE_LFS
  76 #define XATOU_SFX xatoull_sfx
  77 #else
  78 #define XATOU_SFX xatoul_sfx
  79 #endif
  80
  81 int dd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  82 int dd_main(int argc, char **argv)
  83 {
  84         enum {
  85                 FLAG_SYNC    = 1 << 0,
  86                 FLAG_NOERROR = 1 << 1,
  87                 FLAG_NOTRUNC = 1 << 2,
  88                 FLAG_TWOBUFS = 1 << 3,
  89                 FLAG_COUNT   = 1 << 4,
  90         };
  91         static const char keywords[] ALIGN1 =
  92                 "bs=\0""count=\0""seek=\0""skip=\0""if=\0""of=\0"
  93 #if ENABLE_FEATURE_DD_IBS_OBS
  94                 "ibs=\0""obs=\0""conv=\0""notrunc\0""sync\0""noerror\0"
  95 #endif
  96                 ;
  97         enum {
  98                 OP_bs = 1,
  99                 OP_count,
 100                 OP_seek,
 101                 OP_skip,
 102                 OP_if,
 103                 OP_of,
 104 #if ENABLE_FEATURE_DD_IBS_OBS
 105                 OP_ibs,
 106                 OP_obs,
 107                 OP_conv,
 108                 OP_conv_notrunc,
 109                 OP_conv_sync,
 110                 OP_conv_noerror,
 111 #endif
 112         };
 113         int exitcode = EXIT_FAILURE;
 114         size_t ibs = 512, obs = 512;
 115         ssize_t n, w;
 116         char *ibuf, *obuf;
 117         /* And these are all zeroed at once! */
 118         struct {
 119                 int flags;
 120                 size_t oc;
 121                 off_t count;
 122                 off_t seek, skip;
 123                 const char *infile, *outfile;
 124 #if ENABLE_FEATURE_DD_SIGNAL_HANDLING
 125                 struct sigaction sigact;
 126 #endif
 127         } Z;
 128 #define flags   (Z.flags  )
 129 #define oc      (Z.oc     )
 130 #define count   (Z.count  )
 131 #define seek    (Z.seek   )
 132 #define skip    (Z.skip   )
 133 #define infile  (Z.infile )
 134 #define outfile (Z.outfile)
 135 #define sigact  (Z.sigact )
 136
 137         memset(&Z, 0, sizeof(Z));
 138         INIT_G();
 139         //fflush(NULL); - is this needed because of NOEXEC?
 140
 141 #if ENABLE_FEATURE_DD_SIGNAL_HANDLING
 142         sigact.sa_handler = dd_output_status;
 143         sigact.sa_flags = SA_RESTART;
 144         sigemptyset(&sigact.sa_mask);
 145         sigaction(SIGUSR1, &sigact, NULL);
 146 #endif
 147
 148         for (n = 1; n < argc; n++) {
 149                 smalluint key_len;
 150                 smalluint what;
 151                 char *key;
 152                 char *arg = argv[n];
 153
 154 //XXX:FIXME: we reject plain "dd --" This would cost ~20 bytes, so..
 155 //if (*arg == '-' && *++arg == '-' && !*++arg) continue;
 156                 key = strstr(arg, "=");
 157                 if (key == NULL)
 158                         bb_show_usage();
 159                 key_len = key - arg + 1;
 160                 key = xstrndup(arg, key_len);
 161                 what = index_in_strings(keywords, key) + 1;
 162                 if (ENABLE_FEATURE_CLEAN_UP)
 163                         free(key);
 164                 if (what == 0)
 165                         bb_show_usage();
 166                 arg += key_len;
 167                 /* Must fit into positive ssize_t */
 168 #if ENABLE_FEATURE_DD_IBS_OBS
 169                         if (what == OP_ibs) {
 170                                 ibs = xatoul_range_sfx(arg, 1, ((size_t)-1L)/2, dd_suffixes);
 171                                 continue;
 172                         }
 173                         if (what == OP_obs) {
 174                                 obs = xatoul_range_sfx(arg, 1, ((size_t)-1L)/2, dd_suffixes);
 175                                 continue;
 176                         }
 177                         if (what == OP_conv) {
 178                                 while (1) {
 179                                         /* find ',', replace them with nil so we can use arg for
 180                                          * index_in_strings() without copying.
 181                                          * We rely on arg being non-null, else strchr would fault.
 182                                          */
 183                                         key = strchr(arg, ',');
 184                                         if (key)
 185                                                 *key = '\0';
 186                                         what = index_in_strings(keywords, arg) + 1;
 187                                         if (what < OP_conv_notrunc)
 188                                                 bb_error_msg_and_die(bb_msg_invalid_arg, arg, "conv");
 189                                         if (what == OP_conv_notrunc)
 190                                                 flags |= FLAG_NOTRUNC;
 191                                         if (what == OP_conv_sync)
 192                                                 flags |= FLAG_SYNC;
 193                                         if (what == OP_conv_noerror)
 194                                                 flags |= FLAG_NOERROR;
 195                                         if (!key) /* no ',' left, so this was the last specifier */
 196                                                 break;
 197                                         arg = key + 1; /* skip this keyword and ',' */
 198                                 }
 199                                 continue;
 200                         }
 201 #endif
 202                 if (what == OP_bs) {
 203                         ibs = obs = xatoul_range_sfx(arg, 1, ((size_t)-1L)/2, dd_suffixes);
 204                         continue;
 205                 }
 206                 /* These can be large: */
 207                 if (what == OP_count) {
 208                         flags |= FLAG_COUNT;
 209                         count = XATOU_SFX(arg, dd_suffixes);
 210                         continue;
 211                 }
 212                 if (what == OP_seek) {
 213                         seek = XATOU_SFX(arg, dd_suffixes);
 214                         continue;
 215                 }
 216                 if (what == OP_skip) {
 217                         skip = XATOU_SFX(arg, dd_suffixes);
 218                         continue;
 219                 }
 220                 if (what == OP_if) {
 221                         infile = arg;
 222                         continue;
 223                 }
 224                 if (what == OP_of)
 225                         outfile = arg;
 226         }
 227 //XXX:FIXME for huge ibs or obs, malloc'ing them isn't the brightest idea ever
 228         ibuf = obuf = xmalloc(ibs);
 229         if (ibs != obs) {
 230                 flags |= FLAG_TWOBUFS;
 231                 obuf = xmalloc(obs);
 232         }
 233         if (infile != NULL)
 234                 xmove_fd(xopen(infile, O_RDONLY), ifd);
 235         else {
 236                 infile = bb_msg_standard_input;
 237         }
 238         if (outfile != NULL) {
 239                 int oflag = O_WRONLY | O_CREAT;
 240
 241                 if (!seek && !(flags & FLAG_NOTRUNC))
 242                         oflag |= O_TRUNC;
 243
 244                 xmove_fd(xopen(outfile, oflag), ofd);
 245
 246                 if (seek && !(flags & FLAG_NOTRUNC)) {
 247                         if (ftruncate(ofd, seek * obs) < 0) {
 248                                 struct stat st;
 249
 250                                 if (fstat(ofd, &st) < 0 || S_ISREG(st.st_mode) ||
 251                                                 S_ISDIR(st.st_mode))
 252                                         goto die_outfile;
 253                         }
 254                 }
 255         } else {
 256                 outfile = bb_msg_standard_output;
 257         }
 258         if (skip) {
 259                 if (lseek(ifd, skip * ibs, SEEK_CUR) < 0) {
 260                         while (skip-- > 0) {
 261                                 n = safe_read(ifd, ibuf, ibs);
 262                                 if (n < 0)
 263                                         goto die_infile;
 264                                 if (n == 0)
 265                                         break;
 266                         }
 267                 }
 268         }
 269         if (seek) {
 270                 if (lseek(ofd, seek * obs, SEEK_CUR) < 0)
 271                         goto die_outfile;
 272         }
 273
 274         while (!(flags & FLAG_COUNT) || (G.in_full + G.in_part != count)) {
 275                 if (flags & FLAG_NOERROR) /* Pre-zero the buffer if conv=noerror */
 276                         memset(ibuf, 0, ibs);
 277                 n = safe_read(ifd, ibuf, ibs);
 278                 if (n == 0)
 279                         break;
 280                 if (n < 0) {
 281                         if (!(flags & FLAG_NOERROR))
 282                                 goto die_infile;
 283                         n = ibs;
 284                         bb_simple_perror_msg(infile);
 285                 }
 286                 if ((size_t)n == ibs)
 287                         G.in_full++;
 288                 else {
 289                         G.in_part++;
 290                         if (flags & FLAG_SYNC) {
 291                                 memset(ibuf + n, '\0', ibs - n);
 292                                 n = ibs;
 293                         }
 294                 }
 295                 if (flags & FLAG_TWOBUFS) {
 296                         char *tmp = ibuf;
 297                         while (n) {
 298                                 size_t d = obs - oc;
 299
 300                                 if (d > n)
 301                                         d = n;
 302                                 memcpy(obuf + oc, tmp, d);
 303                                 n -= d;
 304                                 tmp += d;
 305                                 oc += d;
 306                                 if (oc == obs) {
 307                                         if (write_and_stats(obuf, obs, obs, outfile))
 308                                                 goto out_status;
 309                                         oc = 0;
 310                                 }
 311                         }
 312                 } else if (write_and_stats(ibuf, n, obs, outfile))
 313                         goto out_status;
 314         }
 315
 316         if (ENABLE_FEATURE_DD_IBS_OBS && oc) {
 317                 w = full_write_or_warn(obuf, oc, outfile);
 318                 if (w < 0) goto out_status;
 319                 if (w > 0)
 320                         G.out_part++;
 321         }
 322         if (close(ifd) < 0) {
 323  die_infile:
 324                 bb_simple_perror_msg_and_die(infile);
 325         }
 326
 327         if (close(ofd) < 0) {
 328  die_outfile:
 329                 bb_simple_perror_msg_and_die(outfile);
 330         }
 331
 332         exitcode = EXIT_SUCCESS;
 333  out_status:
 334         dd_output_status(0);
 335
 336         return exitcode;
 337 }