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 "busybox.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 * const 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 * const keywords[] = {
  82                 "bs=", "count=", "seek=", "skip=", "if=", "of=",
  83 #if ENABLE_FEATURE_DD_IBS_OBS
  84                 "ibs=", "obs=", "conv=", "notrunc", "sync", "noerror",
  85 #endif
  86                 NULL
  87         };
  88         enum {
  89                 OP_bs = 1,
  90                 OP_count,
  91                 OP_seek,
  92                 OP_skip,
  93                 OP_if,
  94                 OP_of,
  95 USE_FEATURE_DD_IBS_OBS(
  96                 OP_ibs,
  97                 OP_obs,
  98                 OP_conv,
  99                 OP_conv_notrunc,
 100                 OP_conv_sync,
 101                 OP_conv_noerror,
 102 )
 103         };
 104         int flags = trunc_flag;
 105         size_t oc = 0, ibs = 512, obs = 512;
 106         ssize_t n, w;
 107         off_t seek = 0, skip = 0, count = OFF_T_MAX;
 108         int ifd, ofd;
 109         const char *infile = NULL, *outfile = NULL;
 110         char *ibuf, *obuf;
 111
 112         if (ENABLE_FEATURE_DD_SIGNAL_HANDLING) {
 113                 struct sigaction sa;
 114
 115                 memset(&sa, 0, sizeof(sa));
 116                 sa.sa_handler = dd_output_status;
 117                 sa.sa_flags = SA_RESTART;
 118                 sigemptyset(&sa.sa_mask);
 119                 sigaction(SIGUSR1, &sa, 0);
 120         }
 121
 122         for (n = 1; n < argc; n++) {
 123                 smalluint key_len;
 124                 smalluint what;
 125                 char *key;
 126                 char *arg = argv[n];
 127
 128 //XXX:FIXME: we reject plain "dd --" This would cost ~20 bytes, so..
 129 //if (*arg == '-' && *++arg == '-' && !*++arg) continue;
 130                 key = strstr(arg, "=");
 131                 if (key == NULL)
 132                         bb_show_usage();
 133                 key_len = key - arg + 1;
 134                 key = xstrndup(arg, key_len);
 135                 what = index_in_str_array(keywords, key) + 1;
 136                 if (ENABLE_FEATURE_CLEAN_UP)
 137                         free(key);
 138                 if (what == 0)
 139                         bb_show_usage();
 140                 arg += key_len;
 141                 /* Must fit into positive ssize_t */
 142                 if (ENABLE_FEATURE_DD_IBS_OBS) {
 143                         if (what == OP_ibs) {
 144                                 ibs = xatoul_range_sfx(arg, 1, ((size_t)-1L)/2, dd_suffixes);
 145                                 continue;
 146                         }
 147                         if (what == OP_obs) {
 148                                 obs = xatoul_range_sfx(arg, 1, ((size_t)-1L)/2, dd_suffixes);
 149                                 continue;
 150                         }
 151                         if (what == OP_conv) {
 152                                 while (1) {
 153                                         /* find ',', replace them with nil so we can use arg for
 154                                          * index_in_str_array without copying.
 155                                          * We rely on arg being non-null, else strstr would fault.
 156                                          */
 157                                         key = strstr(arg, ",");
 158                                         if (key)
 159                                                 *key = '\0';
 160                                         what = index_in_str_array(keywords, arg) + 1;
 161                                         if (what < OP_conv_notrunc)
 162                                                 bb_error_msg_and_die(bb_msg_invalid_arg, arg, "conv");
 163                                         if (what == OP_conv_notrunc)
 164                                                 flags &= ~trunc_flag;
 165                                         if (what == OP_conv_sync)
 166                                                 flags |= sync_flag;
 167                                         if (what == OP_conv_noerror)
 168                                                 flags |= noerror;
 169                                         if (!key) /* no ',' left, so this was the last specifier */
 170                                                 break;
 171                                         arg += key - arg + 1; /* skip this keyword plus ',' */
 172                                 }
 173                                 continue;
 174                         }
 175                 }
 176                 if (what == OP_bs) {
 177                         ibs = obs = xatoul_range_sfx(arg, 1, ((size_t)-1L)/2, dd_suffixes);
 178                         continue;
 179                 }
 180                 /* These can be large: */
 181                 if (what == OP_count) {
 182                         count = XATOU_SFX(arg, dd_suffixes);
 183                         continue;
 184                 }
 185                 if (what == OP_seek) {
 186                         seek = XATOU_SFX(arg, dd_suffixes);
 187                         continue;
 188                 }
 189                 if (what == skip) {
 190                         skip = XATOU_SFX(arg, dd_suffixes);
 191                         continue;
 192                 }
 193                 if (what == OP_if) {
 194                         infile = arg;
 195                         continue;
 196                 }
 197                 if (what == OP_of)
 198                         outfile = arg;
 199         }
 200 //XXX:FIXME for huge ibs or obs, malloc'ing them isn't the brightest idea ever
 201         ibuf = obuf = xmalloc(ibs);
 202         if (ibs != obs) {
 203                 flags |= twobufs_flag;
 204                 obuf = xmalloc(obs);
 205         }
 206         if (infile != NULL)
 207                 ifd = xopen(infile, O_RDONLY);
 208         else {
 209                 ifd = STDIN_FILENO;
 210                 infile = bb_msg_standard_input;
 211         }
 212         if (outfile != NULL) {
 213                 int oflag = O_WRONLY | O_CREAT;
 214
 215                 if (!seek && (flags & trunc_flag))
 216                         oflag |= O_TRUNC;
 217
 218                 ofd = xopen(outfile, oflag);
 219
 220                 if (seek && (flags & trunc_flag)) {
 221                         if (ftruncate(ofd, seek * obs) < 0) {
 222                                 struct stat st;
 223
 224                                 if (fstat(ofd, &st) < 0 || S_ISREG(st.st_mode) ||
 225                                                 S_ISDIR(st.st_mode))
 226                                         goto die_outfile;
 227                         }
 228                 }
 229         } else {
 230                 ofd = STDOUT_FILENO;
 231                 outfile = bb_msg_standard_output;
 232         }
 233         if (skip) {
 234                 if (lseek(ifd, skip * ibs, SEEK_CUR) < 0) {
 235                         while (skip-- > 0) {
 236                                 n = safe_read(ifd, ibuf, ibs);
 237                                 if (n < 0)
 238                                         goto die_infile;
 239                                 if (n == 0)
 240                                         break;
 241                         }
 242                 }
 243         }
 244         if (seek) {
 245                 if (lseek(ofd, seek * obs, SEEK_CUR) < 0)
 246                         goto die_outfile;
 247         }
 248
 249         while (G.in_full + G.in_part != count) {
 250                 if (flags & noerror) /* Pre-zero the buffer when for noerror */
 251                         memset(ibuf, '\0', ibs);
 252                 n = safe_read(ifd, ibuf, ibs);
 253                 if (n == 0)
 254                         break;
 255                 if (n < 0) {
 256                         if (flags & noerror) {
 257                                 n = ibs;
 258                                 bb_perror_msg("%s", infile);
 259                         } else
 260                                 goto die_infile;
 261                 }
 262                 if ((size_t)n == ibs)
 263                         G.in_full++;
 264                 else {
 265                         G.in_part++;
 266                         if (flags & sync_flag) {
 267                                 memset(ibuf + n, '\0', ibs - n);
 268                                 n = ibs;
 269                         }
 270                 }
 271                 if (flags & twobufs_flag) {
 272                         char *tmp = ibuf;
 273                         while (n) {
 274                                 size_t d = obs - oc;
 275
 276                                 if (d > n)
 277                                         d = n;
 278                                 memcpy(obuf + oc, tmp, d);
 279                                 n -= d;
 280                                 tmp += d;
 281                                 oc += d;
 282                                 if (oc == obs) {
 283                                         if (write_and_stats(ofd, obuf, obs, obs, outfile))
 284                                                 goto out_status;
 285                                         oc = 0;
 286                                 }
 287                         }
 288                 } else
 289                         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 }