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 static off_t out_full, out_part, in_full, in_part;
  29
  30 static void dd_output_status(int ATTRIBUTE_UNUSED cur_signal)
  31 {
  32         fprintf(stderr, "%"OFF_FMT"d+%"OFF_FMT"d records in\n"
  33                         "%"OFF_FMT"d+%"OFF_FMT"d records out\n",
  34                         in_full, in_part,
  35                         out_full, out_part);
  36 }
  37
  38 static ssize_t full_write_or_warn(int fd, const void *buf, size_t len,
  39                 const char* filename)
  40 {
  41         ssize_t n = full_write(fd, buf, len);
  42         if (n < 0)
  43                 bb_perror_msg("writing '%s'", filename);
  44         return n;
  45 }
  46
  47 #if ENABLE_LFS
  48 #define XATOU_SFX xatoull_sfx
  49 #else
  50 #define XATOU_SFX xatoul_sfx
  51 #endif
  52
  53 int dd_main(int argc, char **argv);
  54 int dd_main(int argc, char **argv)
  55 {
  56         enum {
  57                 sync_flag    = 1 << 0,
  58                 noerror      = 1 << 1,
  59                 trunc_flag   = 1 << 2,
  60                 twobufs_flag = 1 << 3,
  61         };
  62         int flags = trunc_flag;
  63         size_t oc = 0, ibs = 512, obs = 512;
  64         ssize_t n, w;
  65         off_t seek = 0, skip = 0, count = OFF_T_MAX;
  66         int oflag, ifd, ofd;
  67         const char *infile = NULL, *outfile = NULL;
  68         char *ibuf, *obuf;
  69
  70         if (ENABLE_FEATURE_DD_SIGNAL_HANDLING) {
  71                 struct sigaction sa;
  72
  73                 memset(&sa, 0, sizeof(sa));
  74                 sa.sa_handler = dd_output_status;
  75                 sa.sa_flags = SA_RESTART;
  76                 sigemptyset(&sa.sa_mask);
  77                 sigaction(SIGUSR1, &sa, 0);
  78         }
  79
  80         for (n = 1; n < argc; n++) {
  81                 char *arg = argv[n];
  82                 /* Must fit into positive ssize_t */
  83                 if (ENABLE_FEATURE_DD_IBS_OBS && !strncmp("ibs=", arg, 4))
  84                         ibs = xatoul_range_sfx(arg+4, 0, ((size_t)-1L)/2, dd_suffixes);
  85                 else if (ENABLE_FEATURE_DD_IBS_OBS && !strncmp("obs=", arg, 4))
  86                         obs = xatoul_range_sfx(arg+4, 0, ((size_t)-1L)/2, dd_suffixes);
  87                 else if (!strncmp("bs=", arg, 3))
  88                         ibs = obs = xatoul_range_sfx(arg+3, 0, ((size_t)-1L)/2, dd_suffixes);
  89                 /* These can be large: */
  90                 else if (!strncmp("count=", arg, 6))
  91                         count = XATOU_SFX(arg+6, dd_suffixes);
  92                 else if (!strncmp("seek=", arg, 5))
  93                         seek = XATOU_SFX(arg+5, dd_suffixes);
  94                 else if (!strncmp("skip=", arg, 5))
  95                         skip = XATOU_SFX(arg+5, dd_suffixes);
  96
  97                 else if (!strncmp("if=", arg, 3))
  98                         infile = arg+3;
  99                 else if (!strncmp("of=", arg, 3))
 100                         outfile = arg+3;
 101                 else if (ENABLE_FEATURE_DD_IBS_OBS && !strncmp("conv=", arg, 5)) {
 102                         arg += 5;
 103                         while (1) {
 104                                 if (!strncmp("notrunc", arg, 7)) {
 105                                         flags &= ~trunc_flag;
 106                                         arg += 7;
 107                                 } else if (!strncmp("sync", arg, 4)) {
 108                                         flags |= sync_flag;
 109                                         arg += 4;
 110                                 } else if (!strncmp("noerror", arg, 7)) {
 111                                         flags |= noerror;
 112                                         arg += 7;
 113                                 } else {
 114                                         bb_error_msg_and_die(bb_msg_invalid_arg, arg, "conv");
 115                                 }
 116                                 if (arg[0] == '\0') break;
 117                                 if (*arg++ != ',') bb_show_usage();
 118                         }
 119                 } else
 120                         bb_show_usage();
 121         }
 122
 123         ibuf = obuf = xmalloc(ibs);
 124         if (ibs != obs) {
 125                 flags |= twobufs_flag;
 126                 obuf = xmalloc(obs);
 127         }
 128
 129         if (infile != NULL)
 130                 ifd = xopen(infile, O_RDONLY);
 131         else {
 132                 ifd = STDIN_FILENO;
 133                 infile = bb_msg_standard_input;
 134         }
 135
 136         if (outfile != NULL) {
 137                 oflag = O_WRONLY | O_CREAT;
 138
 139                 if (!seek && (flags & trunc_flag))
 140                         oflag |= O_TRUNC;
 141
 142                 ofd = xopen(outfile, oflag);
 143
 144                 if (seek && (flags & trunc_flag)) {
 145                         if (ftruncate(ofd, seek * obs) < 0) {
 146                                 struct stat st;
 147
 148                                 if (fstat(ofd, &st) < 0 || S_ISREG(st.st_mode) ||
 149                                                 S_ISDIR(st.st_mode))
 150                                         goto die_outfile;
 151                         }
 152                 }
 153         } else {
 154                 ofd = STDOUT_FILENO;
 155                 outfile = bb_msg_standard_output;
 156         }
 157
 158         if (skip) {
 159                 if (lseek(ifd, skip * ibs, SEEK_CUR) < 0) {
 160                         while (skip-- > 0) {
 161                                 n = safe_read(ifd, ibuf, ibs);
 162                                 if (n < 0)
 163                                         bb_perror_msg_and_die("%s", infile);
 164                                 if (n == 0)
 165                                         break;
 166                         }
 167                 }
 168         }
 169
 170         if (seek) {
 171                 if (lseek(ofd, seek * obs, SEEK_CUR) < 0)
 172                         goto die_outfile;
 173         }
 174
 175         while (in_full + in_part != count) {
 176                 if (flags & noerror) {
 177                         /* Pre-zero the buffer when doing the noerror thing */
 178                         memset(ibuf, '\0', ibs);
 179                 }
 180
 181                 n = safe_read(ifd, ibuf, ibs);
 182                 if (n == 0)
 183                         break;
 184                 if (n < 0) {
 185                         if (flags & noerror) {
 186                                 n = ibs;
 187                                 bb_perror_msg("%s", infile);
 188                         } else
 189                                 bb_perror_msg_and_die("%s", infile);
 190                 }
 191                 if ((size_t)n == ibs)
 192                         in_full++;
 193                 else {
 194                         in_part++;
 195                         if (flags & sync_flag) {
 196                                 memset(ibuf + n, '\0', ibs - n);
 197                                 n = ibs;
 198                         }
 199                 }
 200                 if (flags & twobufs_flag) {
 201                         char *tmp = ibuf;
 202                         while (n) {
 203                                 size_t d = obs - oc;
 204
 205                                 if (d > n)
 206                                         d = n;
 207                                 memcpy(obuf + oc, tmp, d);
 208                                 n -= d;
 209                                 tmp += d;
 210                                 oc += d;
 211                                 if (oc == obs) {
 212                                         w = full_write_or_warn(ofd, obuf, obs, outfile);
 213                                         if (w < 0) goto out_status;
 214                                         if (w == obs)
 215                                                 out_full++;
 216                                         else if (w > 0)
 217                                                 out_part++;
 218                                         oc = 0;
 219                                 }
 220                         }
 221                 } else {
 222                         w = full_write_or_warn(ofd, ibuf, n, outfile);
 223                         if (w < 0) goto out_status;
 224                         if (w == obs)
 225                                 out_full++;
 226                         else if (w > 0)
 227                                 out_part++;
 228                 }
 229         }
 230
 231         if (ENABLE_FEATURE_DD_IBS_OBS && oc) {
 232                 w = full_write_or_warn(ofd, obuf, oc, outfile);
 233                 if (w < 0) goto out_status;
 234                 if (w > 0)
 235                         out_part++;
 236         }
 237         if (close(ifd) < 0) {
 238                 bb_perror_msg_and_die("%s", infile);
 239         }
 240
 241         if (close(ofd) < 0) {
 242  die_outfile:
 243                 bb_perror_msg_and_die("%s", outfile);
 244         }
 245  out_status:
 246         dd_output_status(0);
 247
 248         return EXIT_SUCCESS;
 249 }