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