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