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