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         bb_fprintf(stderr, OFF_FMT"+"OFF_FMT" records in\n"
  33                         OFF_FMT"+"OFF_FMT" records out\n",
  34                         in_full, in_part,
  35                         out_full, out_part);
  36 }
  37
  38 int dd_main(int argc, char **argv)
  39 {
  40 #define sync_flag    (1<<0)
  41 #define noerror      (1<<1)
  42 #define trunc_flag   (1<<2)
  43 #define twobufs_flag (1<<3)
  44         int flags = trunc_flag;
  45         size_t oc = 0, ibs = 512, obs = 512;
  46         ssize_t n;
  47         off_t seek = 0, skip = 0, count = OFF_T_MAX;
  48         int oflag, ifd, ofd;
  49         const char *infile = NULL, *outfile = NULL;
  50         char *ibuf, *obuf;
  51
  52         if (ENABLE_FEATURE_DD_SIGNAL_HANDLING) {
  53                 struct sigaction sa;
  54
  55                 memset(&sa, 0, sizeof(sa));
  56                 sa.sa_handler = dd_output_status;
  57                 sa.sa_flags = SA_RESTART;
  58                 sigemptyset(&sa.sa_mask);
  59                 sigaction(SIGUSR1, &sa, 0);
  60         }
  61
  62         for (n = 1; n < argc; n++) {
  63                 // FIXME: make them capable of eating LARGE numbers
  64                 if (ENABLE_FEATURE_DD_IBS_OBS && !strncmp("ibs=", argv[n], 4)) {
  65                         ibs = xatoul_sfx(argv[n]+4, dd_suffixes);
  66                         flags |= twobufs_flag;
  67                 } else if (ENABLE_FEATURE_DD_IBS_OBS && !strncmp("obs=", argv[n], 4)) {
  68                         obs = xatoul_sfx(argv[n]+4, dd_suffixes);
  69                         flags |= twobufs_flag;
  70                 } else if (!strncmp("bs=", argv[n], 3))
  71                         ibs = obs = xatoul_sfx(argv[n]+3, dd_suffixes);
  72                 else if (!strncmp("count=", argv[n], 6))
  73                         count = xatoul_sfx(argv[n]+6, dd_suffixes);
  74                 else if (!strncmp("seek=", argv[n], 5))
  75                         seek = xatoul_sfx(argv[n]+5, dd_suffixes);
  76                 else if (!strncmp("skip=", argv[n], 5))
  77                         skip = xatoul_sfx(argv[n]+5, dd_suffixes);
  78                 else if (!strncmp("if=", argv[n], 3))
  79                         infile = argv[n]+3;
  80                 else if (!strncmp("of=", argv[n], 3))
  81                         outfile = argv[n]+3;
  82                 else if (ENABLE_FEATURE_DD_IBS_OBS && !strncmp("conv=", argv[n], 5)) {
  83                         ibuf = argv[n]+5;
  84                         while (1) {
  85                                 if (!strncmp("notrunc", ibuf, 7)) {
  86                                         flags &= ~trunc_flag;
  87                                         ibuf += 7;
  88                                 } else if (!strncmp("sync", ibuf, 4)) {
  89                                         flags |= sync_flag;
  90                                         ibuf += 4;
  91                                 } else if (!strncmp("noerror", ibuf, 7)) {
  92                                         flags |= noerror;
  93                                         ibuf += 7;
  94                                 } else {
  95                                         bb_error_msg_and_die(bb_msg_invalid_arg, argv[n]+5, "conv");
  96                                 }
  97                                 if (ibuf[0] == '\0') break;
  98                                 if (ibuf[0] == ',') ibuf++;
  99                         }
 100                 } else
 101                         bb_show_usage();
 102         }
 103         ibuf = xmalloc(ibs);
 104
 105         if (flags & twobufs_flag)
 106                 obuf = xmalloc(obs);
 107         else
 108                 obuf = ibuf;
 109
 110         if (infile != NULL)
 111                 ifd = xopen(infile, O_RDONLY);
 112         else {
 113                 ifd = STDIN_FILENO;
 114                 infile = bb_msg_standard_input;
 115         }
 116
 117         if (outfile != NULL) {
 118                 oflag = O_WRONLY | O_CREAT;
 119
 120                 if (!seek && (flags & trunc_flag))
 121                         oflag |= O_TRUNC;
 122
 123                 ofd = xopen3(outfile, oflag, 0666);
 124
 125                 if (seek && (flags & trunc_flag)) {
 126                         if (ftruncate(ofd, seek * obs) < 0) {
 127                                 struct stat st;
 128
 129                                 if (fstat(ofd, &st) < 0 || S_ISREG(st.st_mode) ||
 130                                                 S_ISDIR(st.st_mode))
 131                                         goto die_outfile;
 132                         }
 133                 }
 134         } else {
 135                 ofd = STDOUT_FILENO;
 136                 outfile = bb_msg_standard_output;
 137         }
 138
 139         if (skip) {
 140                 if (lseek(ifd, skip * ibs, SEEK_CUR) < 0) {
 141                         while (skip-- > 0) {
 142                                 n = safe_read(ifd, ibuf, ibs);
 143                                 if (n < 0)
 144                                         bb_perror_msg_and_die("%s", infile);
 145                                 if (n == 0)
 146                                         break;
 147                         }
 148                 }
 149         }
 150
 151         if (seek) {
 152                 if (lseek(ofd, seek * obs, SEEK_CUR) < 0)
 153                         goto die_outfile;
 154         }
 155
 156         while (in_full + in_part != count) {
 157                 if (flags & noerror) {
 158                         /* Pre-zero the buffer when doing the noerror thing */
 159                         memset(ibuf, '\0', ibs);
 160                 }
 161
 162                 n = safe_read(ifd, ibuf, ibs);
 163                 if (n == 0)
 164                         break;
 165                 if (n < 0) {
 166                         if (flags & noerror) {
 167                                 n = ibs;
 168                                 bb_perror_msg("%s", infile);
 169                         } else
 170                                 bb_perror_msg_and_die("%s", infile);
 171                 }
 172                 if ((size_t)n == ibs)
 173                         in_full++;
 174                 else {
 175                         in_part++;
 176                         if (sync_flag) {
 177                                 memset(ibuf + n, '\0', ibs - n);
 178                                 n = ibs;
 179                         }
 180                 }
 181                 if (flags & twobufs_flag) {
 182                         char *tmp = ibuf;
 183                         while (n) {
 184                                 size_t d = obs - oc;
 185
 186                                 if (d > n)
 187                                         d = n;
 188                                 memcpy(obuf + oc, tmp, d);
 189                                 n -= d;
 190                                 tmp += d;
 191                                 oc += d;
 192                                 if (oc == obs) {
 193                                         xwrite(ofd, obuf, obs);
 194                                         out_full++;
 195                                         oc = 0;
 196                                 }
 197                         }
 198                 } else {
 199                         xwrite(ofd, ibuf, n);
 200                         if (n == ibs)
 201                                 out_full++;
 202                         else
 203                                 out_part++;
 204                 }
 205         }
 206
 207         if (ENABLE_FEATURE_DD_IBS_OBS && oc) {
 208                 xwrite(ofd, obuf, oc);
 209                 out_part++;
 210         }
 211         if (close (ifd) < 0) {
 212                 bb_perror_msg_and_die("%s", infile);
 213         }
 214
 215         if (close (ofd) < 0) {
 216 die_outfile:
 217                 bb_perror_msg_and_die("%s", outfile);
 218         }
 219
 220         dd_output_status(0);
 221
 222         return EXIT_SUCCESS;
 223 }