LXR busybox/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 source tree.
   9 */
  10
  11//usage:#define dd_trivial_usage
  12//usage:       "[if=FILE] [of=FILE] " IF_FEATURE_DD_IBS_OBS("[ibs=N] [obs=N] ") "[bs=N] [count=N] [skip=N]\n"
  13//usage:       "        [seek=N]" IF_FEATURE_DD_IBS_OBS(" [conv=notrunc|noerror|sync|fsync]")
  14//usage:#define dd_full_usage "\n\n"
  15//usage:       "Copy a file with converting and formatting\n"
  16//usage:     "\n        if=FILE         Read from FILE instead of stdin"
  17//usage:     "\n        of=FILE         Write to FILE instead of stdout"
  18//usage:     "\n        bs=N            Read and write N bytes at a time"
  19//usage:        IF_FEATURE_DD_IBS_OBS(
  20//usage:     "\n        ibs=N           Read N bytes at a time"
  21//usage:        )
  22//usage:        IF_FEATURE_DD_IBS_OBS(
  23//usage:     "\n        obs=N           Write N bytes at a time"
  24//usage:        )
  25//usage:     "\n        count=N         Copy only N input blocks"
  26//usage:     "\n        skip=N          Skip N input blocks"
  27//usage:     "\n        seek=N          Skip N output blocks"
  28//usage:        IF_FEATURE_DD_IBS_OBS(
  29//usage:     "\n        conv=notrunc    Don't truncate output file"
  30//usage:     "\n        conv=noerror    Continue after read errors"
  31//usage:     "\n        conv=sync       Pad blocks with zeros"
  32//usage:     "\n        conv=fsync      Physically write data out before finishing"
  33//usage:        )
  34//usage:     "\n"
  35//usage:     "\nNumbers may be suffixed by c (x1), w (x2), b (x512), kD (x1000), k (x1024),"
  36//usage:     "\nMD (x1000000), M (x1048576), GD (x1000000000) or G (x1073741824)"
  37//usage:
  38//usage:#define dd_example_usage
  39//usage:       "$ dd if=/dev/zero of=/dev/ram1 bs=1M count=4\n"
  40//usage:       "4+0 records in\n"
  41//usage:       "4+0 records out\n"
  42
  43#include "libbb.h"
  44
  45/* This is a NOEXEC applet. Be very careful! */
  46
  47
  48enum {
  49        ifd = STDIN_FILENO,
  50        ofd = STDOUT_FILENO,
  51};
  52
  53static const struct suffix_mult dd_suffixes[] = {
  54        { "c", 1 },
  55        { "w", 2 },
  56        { "b", 512 },
  57        { "kD", 1000 },
  58        { "k", 1024 },
  59        { "K", 1024 },  /* compat with coreutils dd */
  60        { "MD", 1000000 },
  61        { "M", 1048576 },
  62        { "GD", 1000000000 },
  63        { "G", 1073741824 },
  64        { "", 0 }
  65};
  66
  67struct globals {
  68        off_t out_full, out_part, in_full, in_part;
  69#if ENABLE_FEATURE_DD_THIRD_STATUS_LINE
  70        unsigned long long total_bytes;
  71        unsigned long long begin_time_us;
  72#endif
  73} FIX_ALIASING;
  74#define G (*(struct globals*)&bb_common_bufsiz1)
  75#define INIT_G() do { \
  76        /* we have to zero it out because of NOEXEC */ \
  77        memset(&G, 0, sizeof(G)); \
  78} while (0)
  79
  80
  81static void dd_output_status(int UNUSED_PARAM cur_signal)
  82{
  83#if ENABLE_FEATURE_DD_THIRD_STATUS_LINE
  84        double seconds;
  85        unsigned long long bytes_sec;
  86        unsigned long long now_us = monotonic_us(); /* before fprintf */
  87#endif
  88
  89        /* Deliberately using %u, not %d */
  90        fprintf(stderr, "%"OFF_FMT"u+%"OFF_FMT"u records in\n"
  91                        "%"OFF_FMT"u+%"OFF_FMT"u records out\n",
  92                        G.in_full, G.in_part,
  93                        G.out_full, G.out_part);
  94
  95#if ENABLE_FEATURE_DD_THIRD_STATUS_LINE
  96        fprintf(stderr, "%llu bytes (%sB) copied, ",
  97                        G.total_bytes,
  98                        /* show fractional digit, use suffixes */
  99                        make_human_readable_str(G.total_bytes, 1, 0)
 100        );
 101        /* Corner cases:
 102         * ./busybox dd </dev/null >/dev/null
 103         * ./busybox dd bs=1M count=2000 </dev/zero >/dev/null
 104         * (echo DONE) | ./busybox dd >/dev/null
 105         * (sleep 1; echo DONE) | ./busybox dd >/dev/null
 106         */
 107        seconds = (now_us - G.begin_time_us) / 1000000.0;
 108        bytes_sec = G.total_bytes / seconds;
 109        fprintf(stderr, "%f seconds, %sB/s\n",
 110                        seconds,
 111                        /* show fractional digit, use suffixes */
 112                        make_human_readable_str(bytes_sec, 1, 0)
 113        );
 114#endif
 115}
 116
 117static ssize_t full_write_or_warn(const void *buf, size_t len,
 118        const char *const filename)
 119{
 120        ssize_t n = full_write(ofd, buf, len);
 121        if (n < 0)
 122                bb_perror_msg("writing '%s'", filename);
 123        return n;
 124}
 125
 126static bool write_and_stats(const void *buf, size_t len, size_t obs,
 127        const char *filename)
 128{
 129        ssize_t n = full_write_or_warn(buf, len, filename);
 130        if (n < 0)
 131                return 1;
 132        if ((size_t)n == obs)
 133                G.out_full++;
 134        else if (n) /* > 0 */
 135                G.out_part++;
 136#if ENABLE_FEATURE_DD_THIRD_STATUS_LINE
 137        G.total_bytes += n;
 138#endif
 139        return 0;
 140}
 141
 142#if ENABLE_LFS
 143# define XATOU_SFX xatoull_sfx
 144#else
 145# define XATOU_SFX xatoul_sfx
 146#endif
 147
 148int dd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 149int dd_main(int argc UNUSED_PARAM, char **argv)
 150{
 151        enum {
 152                /* Must be in the same order as OP_conv_XXX! */
 153                /* (see "flags |= (1 << what)" below) */
 154                FLAG_NOTRUNC = 1 << 0,
 155                FLAG_SYNC    = 1 << 1,
 156                FLAG_NOERROR = 1 << 2,
 157                FLAG_FSYNC   = 1 << 3,
 158                /* end of conv flags */
 159                FLAG_TWOBUFS = 1 << 4,
 160                FLAG_COUNT   = 1 << 5,
 161        };
 162        static const char keywords[] ALIGN1 =
 163                "bs\0""count\0""seek\0""skip\0""if\0""of\0"
 164#if ENABLE_FEATURE_DD_IBS_OBS
 165                "ibs\0""obs\0""conv\0"
 166#endif
 167                ;
 168#if ENABLE_FEATURE_DD_IBS_OBS
 169        static const char conv_words[] ALIGN1 =
 170                "notrunc\0""sync\0""noerror\0""fsync\0";
 171#endif
 172        enum {
 173                OP_bs = 0,
 174                OP_count,
 175                OP_seek,
 176                OP_skip,
 177                OP_if,
 178                OP_of,
 179#if ENABLE_FEATURE_DD_IBS_OBS
 180                OP_ibs,
 181                OP_obs,
 182                OP_conv,
 183                /* Must be in the same order as FLAG_XXX! */
 184                OP_conv_notrunc = 0,
 185                OP_conv_sync,
 186                OP_conv_noerror,
 187                OP_conv_fsync,
 188        /* Unimplemented conv=XXX: */
 189        //nocreat       do not create the output file
 190        //excl          fail if the output file already exists
 191        //fdatasync     physically write output file data before finishing
 192        //swab          swap every pair of input bytes
 193        //lcase         change upper case to lower case
 194        //ucase         change lower case to upper case
 195        //block         pad newline-terminated records with spaces to cbs-size
 196        //unblock       replace trailing spaces in cbs-size records with newline
 197        //ascii         from EBCDIC to ASCII
 198        //ebcdic        from ASCII to EBCDIC
 199        //ibm           from ASCII to alternate EBCDIC
 200#endif
 201        };
 202        int exitcode = EXIT_FAILURE;
 203        size_t ibs = 512, obs = 512;
 204        ssize_t n, w;
 205        char *ibuf, *obuf;
 206        /* And these are all zeroed at once! */
 207        struct {
 208                int flags;
 209                size_t oc;
 210                off_t count;
 211                off_t seek, skip;
 212                const char *infile, *outfile;
 213        } Z;
 214#define flags   (Z.flags  )
 215#define oc      (Z.oc     )
 216#define count   (Z.count  )
 217#define seek    (Z.seek   )
 218#define skip    (Z.skip   )
 219#define infile  (Z.infile )
 220#define outfile (Z.outfile)
 221
 222        memset(&Z, 0, sizeof(Z));
 223        INIT_G();
 224        //fflush_all(); - is this needed because of NOEXEC?
 225
 226        for (n = 1; argv[n]; n++) {
 227                int what;
 228                char *val;
 229                char *arg = argv[n];
 230
 231#if ENABLE_DESKTOP
 232                /* "dd --". NB: coreutils 6.9 will complain if they see
 233                 * more than one of them. We wouldn't. */
 234                if (arg[0] == '-' && arg[1] == '-' && arg[2] == '\0')
 235                        continue;
 236#endif
 237                val = strchr(arg, '=');
 238                if (val == NULL)
 239                        bb_show_usage();
 240                *val = '\0';
 241                what = index_in_strings(keywords, arg);
 242                if (what < 0)
 243                        bb_show_usage();
 244                /* *val = '='; - to preserve ps listing? */
 245                val++;
 246#if ENABLE_FEATURE_DD_IBS_OBS
 247                if (what == OP_ibs) {
 248                        /* Must fit into positive ssize_t */
 249                        ibs = xatoul_range_sfx(val, 1, ((size_t)-1L)/2, dd_suffixes);
 250                        /*continue;*/
 251                }
 252                if (what == OP_obs) {
 253                        obs = xatoul_range_sfx(val, 1, ((size_t)-1L)/2, dd_suffixes);
 254                        /*continue;*/
 255                }
 256                if (what == OP_conv) {
 257                        while (1) {
 258                                /* find ',', replace them with NUL so we can use val for
 259                                 * index_in_strings() without copying.
 260                                 * We rely on val being non-null, else strchr would fault.
 261                                 */
 262                                arg = strchr(val, ',');
 263                                if (arg)
 264                                        *arg = '\0';
 265                                what = index_in_strings(conv_words, val);
 266                                if (what < 0)
 267                                        bb_error_msg_and_die(bb_msg_invalid_arg, val, "conv");
 268                                flags |= (1 << what);
 269                                if (!arg) /* no ',' left, so this was the last specifier */
 270                                        break;
 271                                /* *arg = ','; - to preserve ps listing? */
 272                                val = arg + 1; /* skip this keyword and ',' */
 273                        }
 274                        continue; /* we trashed 'what', can't fall through */
 275                }
 276#endif
 277                if (what == OP_bs) {
 278                        ibs = obs = xatoul_range_sfx(val, 1, ((size_t)-1L)/2, dd_suffixes);
 279                        /*continue;*/
 280                }
 281                /* These can be large: */
 282                if (what == OP_count) {
 283                        flags |= FLAG_COUNT;
 284                        count = XATOU_SFX(val, dd_suffixes);
 285                        /*continue;*/
 286                }
 287                if (what == OP_seek) {
 288                        seek = XATOU_SFX(val, dd_suffixes);
 289                        /*continue;*/
 290                }
 291                if (what == OP_skip) {
 292                        skip = XATOU_SFX(val, dd_suffixes);
 293                        /*continue;*/
 294                }
 295                if (what == OP_if) {
 296                        infile = val;
 297                        /*continue;*/
 298                }
 299                if (what == OP_of) {
 300                        outfile = val;
 301                        /*continue;*/
 302                }
 303        } /* end of "for (argv[n])" */
 304
 305//XXX:FIXME for huge ibs or obs, malloc'ing them isn't the brightest idea ever
 306        ibuf = obuf = xmalloc(ibs);
 307        if (ibs != obs) {
 308                flags |= FLAG_TWOBUFS;
 309                obuf = xmalloc(obs);
 310        }
 311
 312#if ENABLE_FEATURE_DD_SIGNAL_HANDLING
 313        signal_SA_RESTART_empty_mask(SIGUSR1, dd_output_status);
 314#endif
 315#if ENABLE_FEATURE_DD_THIRD_STATUS_LINE
 316        G.begin_time_us = monotonic_us();
 317#endif
 318
 319        if (infile != NULL)
 320                xmove_fd(xopen(infile, O_RDONLY), ifd);
 321        else {
 322                infile = bb_msg_standard_input;
 323        }
 324        if (outfile != NULL) {
 325                int oflag = O_WRONLY | O_CREAT;
 326
 327                if (!seek && !(flags & FLAG_NOTRUNC))
 328                        oflag |= O_TRUNC;
 329
 330                xmove_fd(xopen(outfile, oflag), ofd);
 331
 332                if (seek && !(flags & FLAG_NOTRUNC)) {
 333                        if (ftruncate(ofd, seek * obs) < 0) {
 334                                struct stat st;
 335
 336                                if (fstat(ofd, &st) < 0
 337                                 || S_ISREG(st.st_mode)
 338                                 || S_ISDIR(st.st_mode)
 339                                ) {
 340                                        goto die_outfile;
 341                                }
 342                        }
 343                }
 344        } else {
 345                outfile = bb_msg_standard_output;
 346        }
 347        if (skip) {
 348                if (lseek(ifd, skip * ibs, SEEK_CUR) < 0) {
 349                        while (skip-- > 0) {
 350                                n = safe_read(ifd, ibuf, ibs);
 351                                if (n < 0)
 352                                        goto die_infile;
 353                                if (n == 0)
 354                                        break;
 355                        }
 356                }
 357        }
 358        if (seek) {
 359                if (lseek(ofd, seek * obs, SEEK_CUR) < 0)
 360                        goto die_outfile;
 361        }
 362
 363        while (!(flags & FLAG_COUNT) || (G.in_full + G.in_part != count)) {
 364                n = safe_read(ifd, ibuf, ibs);
 365                if (n == 0)
 366                        break;
 367                if (n < 0) {
 368                        /* "Bad block" */
 369                        if (!(flags & FLAG_NOERROR))
 370                                goto die_infile;
 371                        bb_simple_perror_msg(infile);
 372                        /* GNU dd with conv=noerror skips over bad blocks */
 373                        xlseek(ifd, ibs, SEEK_CUR);
 374                        /* conv=noerror,sync writes NULs,
 375                         * conv=noerror just ignores input bad blocks */
 376                        n = 0;
 377                }
 378                if ((size_t)n == ibs)
 379                        G.in_full++;
 380                else {
 381                        G.in_part++;
 382                        if (flags & FLAG_SYNC) {
 383                                memset(ibuf + n, 0, ibs - n);
 384                                n = ibs;
 385                        }
 386                }
 387                if (flags & FLAG_TWOBUFS) {
 388                        char *tmp = ibuf;
 389                        while (n) {
 390                                size_t d = obs - oc;
 391
 392                                if (d > (size_t)n)
 393                                        d = n;
 394                                memcpy(obuf + oc, tmp, d);
 395                                n -= d;
 396                                tmp += d;
 397                                oc += d;
 398                                if (oc == obs) {
 399                                        if (write_and_stats(obuf, obs, obs, outfile))
 400                                                goto out_status;
 401                                        oc = 0;
 402                                }
 403                        }
 404                } else if (write_and_stats(ibuf, n, obs, outfile))
 405                        goto out_status;
 406
 407                if (flags & FLAG_FSYNC) {
 408                        if (fsync(ofd) < 0)
 409                                goto die_outfile;
 410                }
 411        }
 412
 413        if (ENABLE_FEATURE_DD_IBS_OBS && oc) {
 414                w = full_write_or_warn(obuf, oc, outfile);
 415                if (w < 0) goto out_status;
 416                if (w > 0) G.out_part++;
 417        }
 418        if (close(ifd) < 0) {
 419 die_infile:
 420                bb_simple_perror_msg_and_die(infile);
 421        }
 422
 423        if (close(ofd) < 0) {
 424 die_outfile:
 425                bb_simple_perror_msg_and_die(outfile);
 426        }
 427
 428        exitcode = EXIT_SUCCESS;
 429 out_status:
 430        dd_output_status(0);
 431
 432        if (ENABLE_FEATURE_CLEAN_UP) {
 433                free(obuf);
 434                if (flags & FLAG_TWOBUFS)
 435                        free(ibuf);
 436        }
 437
 438        return exitcode;
 439}
 440