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
  13 static const struct suffix_mult dd_suffixes[] = {
  14         { "c", 1 },
  15         { "w", 2 },
  16         { "b", 512 },
  17         { "kD", 1000 },
  18         { "k", 1024 },
  19         { "MD", 1000000 },
  20         { "M", 1048576 },
  21         { "GD", 1000000000 },
  22         { "G", 1073741824 },
  23         { NULL, 0 }
  24 };
  25
  26 static size_t out_full;
  27 static size_t out_part;
  28 static size_t in_full;
  29 static size_t in_part;
  30
  31 static void dd_output_status(int cur_signal)
  32 {
  33         fprintf(stderr, "%ld+%ld records in\n%ld+%ld records out\n",
  34                         (long)in_full, (long)in_part,
  35                         (long)out_full, (long)out_part);
  36 }
  37
  38 int dd_main(int argc, char **argv)
  39 {
  40         size_t count = -1, oc = 0, ibs = 512, obs = 512;
  41         ssize_t n;
  42         off_t seek = 0, skip = 0;
  43         int sync_flag = FALSE, noerror = FALSE, trunc_flag = TRUE, twobufs_flag = 0,
  44                 oflag, ifd, ofd, i;
  45         const char *infile = NULL, *outfile = NULL;
  46         char *ibuf, *obuf;
  47
  48         if (ENABLE_FEATURE_DD_SIGNAL_HANDLING)
  49         {
  50                 struct sigaction sa;
  51
  52                 memset(&sa, 0, sizeof(sa));
  53                 sa.sa_handler = dd_output_status;
  54                 sa.sa_flags = SA_RESTART;
  55                 sigemptyset(&sa.sa_mask);
  56                 sigaction(SIGUSR1, &sa, 0);
  57         }
  58
  59         for (i = 1; i < argc; i++) {
  60                 if (ENABLE_FEATURE_DD_IBS_OBS && !strncmp("ibs=", argv[i], 4)) {
  61                         ibs = bb_xparse_number(argv[i]+4, dd_suffixes);
  62                         twobufs_flag++;
  63                 } else if (ENABLE_FEATURE_DD_IBS_OBS && !strncmp("obs=", argv[i], 4)) {
  64                         obs = bb_xparse_number(argv[i]+4, dd_suffixes);
  65                         twobufs_flag++;
  66                 } else if (!strncmp("bs=", argv[i], 3)) {
  67                         ibs = obs = bb_xparse_number(argv[i]+3, dd_suffixes);
  68                 } else if (!strncmp("count=", argv[i], 6))
  69                         count = bb_xparse_number(argv[i]+6, dd_suffixes);
  70                 else if (!strncmp("seek=", argv[i], 5))
  71                         seek = bb_xparse_number(argv[i]+5, dd_suffixes);
  72                 else if (!strncmp("skip=", argv[i], 5))
  73                         skip = bb_xparse_number(argv[i]+5, dd_suffixes);
  74                 else if (!strncmp("if=", argv[i], 3))
  75                         infile = argv[i]+3;
  76                 else if (!strncmp("of=", argv[i], 3))
  77                         outfile = argv[i]+3;
  78                 else if (ENABLE_FEATURE_DD_IBS_OBS && !strncmp("conv=", argv[i], 5)) {
  79                         ibuf = argv[i]+5;
  80                         while (1) {
  81                                 if (!strncmp("notrunc", ibuf, 7)) {
  82                                         trunc_flag = FALSE;
  83                                         ibuf += 7;
  84                                 } else if (!strncmp("sync", ibuf, 4)) {
  85                                         sync_flag = TRUE;
  86                                         ibuf += 4;
  87                                 } else if (!strncmp("noerror", ibuf, 7)) {
  88                                         noerror = TRUE;
  89                                         ibuf += 7;
  90                                 } else {
  91                                         bb_error_msg_and_die(bb_msg_invalid_arg, argv[i]+5, "conv");
  92                                 }
  93                                 if (ibuf[0] == '\0') break;
  94                                 if (ibuf[0] == ',') ibuf++;
  95                         }
  96                 } else
  97                         bb_show_usage();
  98         }
  99         ibuf = xmalloc(ibs);
 100
 101         if (twobufs_flag) obuf = xmalloc(obs);
 102         else obuf = ibuf;
 103
 104         if (infile != NULL) {
 105                 ifd = xopen(infile, O_RDONLY);
 106         } else {
 107                 ifd = STDIN_FILENO;
 108                 infile = bb_msg_standard_input;
 109         }
 110
 111         if (outfile != NULL) {
 112                 oflag = O_WRONLY | O_CREAT;
 113
 114                 if (!seek && trunc_flag) {
 115                         oflag |= O_TRUNC;
 116                 }
 117
 118                 ofd = xopen3(outfile, oflag, 0666);
 119
 120                 if (seek && trunc_flag) {
 121                         if (ftruncate(ofd, seek * obs) < 0) {
 122                                 struct stat st;
 123
 124                                 if (fstat (ofd, &st) < 0 || S_ISREG (st.st_mode) ||
 125                                                 S_ISDIR (st.st_mode)) {
 126                                         bb_perror_msg_and_die("%s", outfile);
 127                                 }
 128                         }
 129                 }
 130         } else {
 131                 ofd = STDOUT_FILENO;
 132                 outfile = bb_msg_standard_output;
 133         }
 134
 135         if (skip) {
 136                 if (lseek(ifd, skip * ibs, SEEK_CUR) < 0) {
 137                         while (skip-- > 0) {
 138                                 n = safe_read(ifd, ibuf, ibs);
 139                                 if (n < 0)
 140                                         bb_perror_msg_and_die("%s", infile);
 141                                 if (n == 0)
 142                                         break;
 143                         }
 144                 }
 145         }
 146
 147         if (seek) {
 148                 if (lseek(ofd, seek * obs, SEEK_CUR) < 0) {
 149                         bb_perror_msg_and_die("%s", outfile);
 150                 }
 151         }
 152
 153         while (in_full + in_part != count) {
 154                 if (noerror) {
 155                         /* Pre-zero the buffer when doing the noerror thing */
 156                         memset(ibuf, '\0', ibs);
 157                 }
 158
 159                 n = safe_read(ifd, ibuf, ibs);
 160                 if (n == 0) {
 161                         break;
 162                 }
 163                 if (n < 0) {
 164                         if (noerror) {
 165                                 n = ibs;
 166                                 bb_perror_msg("%s", infile);
 167                         } else {
 168                                 bb_perror_msg_and_die("%s", infile);
 169                         }
 170                 }
 171                 if ((size_t)n == ibs) {
 172                         in_full++;
 173                 } else {
 174                         in_part++;
 175                         if (sync_flag) {
 176                                 memset(ibuf + n, '\0', ibs - n);
 177                                 n = ibs;
 178                         }
 179                 }
 180                 if (twobufs_flag) {
 181                         char *tmp = ibuf;
 182                         while (n) {
 183                                 size_t d = obs - oc;
 184
 185                                 if (d > n) d = n;
 186                                 memcpy(obuf + oc, tmp, d);
 187                                 n -= d;
 188                                 tmp += d;
 189                                 oc += d;
 190                                 if (oc == obs) {
 191                                         xwrite(ofd, obuf, obs);
 192                                         out_full++;
 193                                         oc = 0;
 194                                 }
 195                         }
 196                 } else {
 197                         xwrite(ofd, ibuf, n);
 198                         if (n == ibs) out_full++;
 199                         else out_part++;
 200                 }
 201         }
 202
 203         if (ENABLE_FEATURE_DD_IBS_OBS && oc) {
 204                 xwrite(ofd, obuf, oc);
 205                 out_part++;
 206         }
 207         if (close (ifd) < 0) {
 208                 bb_perror_msg_and_die("%s", infile);
 209         }
 210
 211         if (close (ofd) < 0) {
 212                 bb_perror_msg_and_die("%s", outfile);
 213         }
 214
 215         dd_output_status(0);
 216
 217         return EXIT_SUCCESS;
 218 }