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 "busybox.h"
  12 #include <signal.h>  /* For FEATURE_DD_SIGNAL_HANDLING */
  13
  14 static const struct suffix_mult dd_suffixes[] = {
  15         { "c", 1 },
  16         { "w", 2 },
  17         { "b", 512 },
  18         { "kD", 1000 },
  19         { "k", 1024 },
  20         { "K", 1024 },  /* compat with coreutils dd */
  21         { "MD", 1000000 },
  22         { "M", 1048576 },
  23         { "GD", 1000000000 },
  24         { "G", 1073741824 },
  25         { NULL, 0 }
  26 };
  27
  28 struct globals {
  29         off_t out_full, out_part, in_full, in_part;
  30 };
  31 #define G (*(struct globals*)&bb_common_bufsiz1)
  32
  33 static void dd_output_status(int ATTRIBUTE_UNUSED cur_signal)
  34 {
  35         fprintf(stderr, "%"OFF_FMT"d+%"OFF_FMT"d records in\n"
  36                         "%"OFF_FMT"d+%"OFF_FMT"d records out\n",
  37                         G.in_full, G.in_part,
  38                         G.out_full, G.out_part);
  39 }
  40
  41 static ssize_t full_write_or_warn(int fd, const void *buf, size_t len,
  42         const char * const filename)
  43 {
  44         ssize_t n = full_write(fd, buf, len);
  45         if (n < 0)
  46                 bb_perror_msg("writing '%s'", filename);
  47         return n;
  48 }
  49
  50 static bool write_and_stats(int fd, const void *buf, size_t len, size_t obs,
  51         const char * const filename)
  52 {
  53         ssize_t n = full_write_or_warn(fd, buf, len, filename);
  54         if (n < 0)
  55                 return 1;
  56         if (n == obs)
  57                 G.out_full++;
  58         else if (n > 0)
  59                 G.out_part++;
  60         return 0;
  61 }
  62
  63 #if ENABLE_LFS
  64 #define XATOU_SFX xatoull_sfx
  65 #else
  66 #define XATOU_SFX xatoul_sfx
  67 #endif
  68
  69 int dd_main(int argc, char **argv);
  70 int dd_main(int argc, char **argv)
  71 {
  72         enum {
  73                 sync_flag    = 1 << 0,
  74                 noerror      = 1 << 1,
  75                 trunc_flag   = 1 << 2,
  76                 twobufs_flag = 1 << 3,
  77         };
  78         const char * const keywords[] = {
  79                 "bs=", "count=", "seek=", "skip=", "if=", "of=",
  80 #if ENABLE_FEATURE_DD_IBS_OBS
  81                 "ibs=", "obs=", "conv=", "notrunc", "sync", "noerror",
  82 #endif
  83                 NULL
  84         };
  85 #define OP_bs           0 + 1
  86 #define OP_count        OP_bs + 1
  87 #define OP_seek         OP_count + 1
  88 #define OP_skip         OP_seek + 1
  89 #define OP_if           OP_skip + 1
  90 #define OP_of           OP_if + 1
  91 #define OP_ibs          OP_of + ENABLE_FEATURE_DD_IBS_OBS
  92 #define OP_obs          OP_ibs + ENABLE_FEATURE_DD_IBS_OBS
  93 #define OP_conv         OP_obs + ENABLE_FEATURE_DD_IBS_OBS
  94 #define OP_conv_notrunc OP_conv + ENABLE_FEATURE_DD_IBS_OBS
  95 #define OP_conv_sync    OP_conv_notrunc + ENABLE_FEATURE_DD_IBS_OBS
  96 #define OP_conv_noerror OP_conv_sync + ENABLE_FEATURE_DD_IBS_OBS
  97
  98         int flags = trunc_flag;
  99         size_t oc = 0, ibs = 512, obs = 512;
 100         ssize_t n, w;
 101         off_t seek = 0, skip = 0, count = OFF_T_MAX;
 102         int ifd, ofd;
 103         const char *infile = NULL, *outfile = NULL;
 104         char *ibuf, *obuf;
 105
 106         if (ENABLE_FEATURE_DD_SIGNAL_HANDLING) {
 107                 struct sigaction sa;
 108
 109                 memset(&sa, 0, sizeof(sa));
 110                 sa.sa_handler = dd_output_status;
 111                 sa.sa_flags = SA_RESTART;
 112                 sigemptyset(&sa.sa_mask);
 113                 sigaction(SIGUSR1, &sa, 0);
 114         }
 115
 116         for (n = 1; n < argc; n++) {
 117                 smalluint key_len, what;
 118                 char *key;
 119                 char *arg = argv[n];
 120
 121 //XXX:FIXME: we reject plain "dd --" This would cost ~20 bytes, so..
 122 //if (*arg == '-' && *++arg == '-' && !*++arg) continue;
 123                 key = strstr(arg, "=");
 124                 if (key == NULL)
 125                         bb_show_usage();
 126                 key_len = key - arg + 1;
 127                 key = xstrndup(arg, key_len);
 128                 what = index_in_str_array(keywords, key) + 1;
 129                 if (ENABLE_FEATURE_CLEAN_UP)
 130                         free(key);
 131                 if (what == 0)
 132                         bb_show_usage();
 133                 arg += key_len;
 134                 /* Must fit into positive ssize_t */
 135                 if (ENABLE_FEATURE_DD_IBS_OBS) {
 136                         if (what == OP_ibs) {
 137                                 ibs = xatoul_range_sfx(arg, 1, ((size_t)-1L)/2, dd_suffixes);
 138                                 continue;
 139                         }
 140                         if (what == OP_obs) {
 141                                 obs = xatoul_range_sfx(arg, 1, ((size_t)-1L)/2, dd_suffixes);
 142                                 continue;
 143                         }
 144                         if (what == OP_conv) {
 145                                 while (1) {
 146                                         /* find ',', replace them with nil so we can use arg for
 147                                          * index_in_str_array without copying.
 148                                          * We rely on arg being non-null, else strstr would fault.
 149                                          */
 150                                         key = strstr(arg, ",");
 151                                         if (key)
 152                                                 *key = '\0';
 153                                         what = index_in_str_array(keywords, arg) + 1;
 154                                         if (what < OP_conv_notrunc)
 155                                                 bb_error_msg_and_die(bb_msg_invalid_arg, arg, "conv");
 156                                         if (what == OP_conv_notrunc)
 157                                                 flags &= ~trunc_flag;
 158                                         if (what == OP_conv_sync)
 159                                                 flags |= sync_flag;
 160                                         if (what == OP_conv_noerror)
 161                                                 flags |= noerror;
 162                                         if (!key) /* no ',' left, so this was the last specifier */
 163                                                 break;
 164                                         arg += key - arg + 1; /* skip this keyword plus ',' */
 165                                 }
 166                                 continue;
 167                         }
 168                 }
 169                 if (what == OP_bs) {
 170                         ibs = obs = xatoul_range_sfx(arg, 1, ((size_t)-1L)/2, dd_suffixes);
 171                         continue;
 172                 }
 173                 /* These can be large: */
 174                 if (what == OP_count) {
 175                         count = XATOU_SFX(arg, dd_suffixes);
 176                         continue;
 177                 }
 178                 if (what == OP_seek) {
 179                         seek = XATOU_SFX(arg, dd_suffixes);
 180                         continue;
 181                 }
 182                 if (what == skip) {
 183                         skip = XATOU_SFX(arg, dd_suffixes);
 184                         continue;
 185                 }
 186                 if (what == OP_if) {
 187                         infile = arg;
 188                         continue;
 189                 }
 190                 if (what == OP_of)
 191                         outfile = arg;
 192         }
 193 //XXX:FIXME for huge ibs or obs, malloc'ing them isn't the brightest idea ever
 194         ibuf = obuf = xmalloc(ibs);
 195         if (ibs != obs) {
 196                 flags |= twobufs_flag;
 197                 obuf = xmalloc(obs);
 198         }
 199         if (infile != NULL)
 200                 ifd = xopen(infile, O_RDONLY);
 201         else {
 202                 ifd = STDIN_FILENO;
 203                 infile = bb_msg_standard_input;
 204         }
 205         if (outfile != NULL) {
 206                 int oflag = O_WRONLY | O_CREAT;
 207
 208                 if (!seek && (flags & trunc_flag))
 209                         oflag |= O_TRUNC;
 210
 211                 ofd = xopen(outfile, oflag);
 212
 213                 if (seek && (flags & trunc_flag)) {
 214                         if (ftruncate(ofd, seek * obs) < 0) {
 215                                 struct stat st;
 216
 217                                 if (fstat(ofd, &st) < 0 || S_ISREG(st.st_mode) ||
 218                                                 S_ISDIR(st.st_mode))
 219                                         goto die_outfile;
 220                         }
 221                 }
 222         } else {
 223                 ofd = STDOUT_FILENO;
 224                 outfile = bb_msg_standard_output;
 225         }
 226         if (skip) {
 227                 if (lseek(ifd, skip * ibs, SEEK_CUR) < 0) {
 228                         while (skip-- > 0) {
 229                                 n = safe_read(ifd, ibuf, ibs);
 230                                 if (n < 0)
 231                                         goto die_infile;
 232                                 if (n == 0)
 233                                         break;
 234                         }
 235                 }
 236         }
 237         if (seek) {
 238                 if (lseek(ofd, seek * obs, SEEK_CUR) < 0)
 239                         goto die_outfile;
 240         }
 241
 242         while (G.in_full + G.in_part != count) {
 243                 if (flags & noerror) /* Pre-zero the buffer when for noerror */
 244                         memset(ibuf, '\0', ibs);
 245                 n = safe_read(ifd, ibuf, ibs);
 246                 if (n == 0)
 247                         break;
 248                 if (n < 0) {
 249                         if (flags & noerror) {
 250                                 n = ibs;
 251                                 bb_perror_msg("%s", infile);
 252                         } else
 253                                 goto die_infile;
 254                 }
 255                 if ((size_t)n == ibs)
 256                         G.in_full++;
 257                 else {
 258                         G.in_part++;
 259                         if (flags & sync_flag) {
 260                                 memset(ibuf + n, '\0', ibs - n);
 261                                 n = ibs;
 262                         }
 263                 }
 264                 if (flags & twobufs_flag) {
 265                         char *tmp = ibuf;
 266                         while (n) {
 267                                 size_t d = obs - oc;
 268
 269                                 if (d > n)
 270                                         d = n;
 271                                 memcpy(obuf + oc, tmp, d);
 272                                 n -= d;
 273                                 tmp += d;
 274                                 oc += d;
 275                                 if (oc == obs) {
 276                                         if (write_and_stats(ofd, obuf, obs, obs, outfile))
 277                                                 goto out_status;
 278                                         oc = 0;
 279                                 }
 280                         }
 281                 } else
 282                         if (write_and_stats(ofd, ibuf, n, obs, outfile))
 283                                 goto out_status;
 284         }
 285
 286         if (ENABLE_FEATURE_DD_IBS_OBS && oc) {
 287                 w = full_write_or_warn(ofd, obuf, oc, outfile);
 288                 if (w < 0) goto out_status;
 289                 if (w > 0)
 290                         G.out_part++;
 291         }
 292         if (close(ifd) < 0) {
 293 die_infile:
 294                 bb_perror_msg_and_die("%s", infile);
 295         }
 296
 297         if (close(ofd) < 0) {
 298 die_outfile:
 299                 bb_perror_msg_and_die("%s", outfile);
 300         }
 301 out_status:
 302         dd_output_status(0);
 303
 304         return EXIT_SUCCESS;
 305 }