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 <sys/types.h>
  12 #include <sys/stat.h>
  13 #include <stdlib.h>
  14 #include <stdio.h>
  15 #include <unistd.h>
  16 #include <string.h>
  17 #include <fcntl.h>
  18 #include <signal.h>  // For FEATURE_DD_SIGNAL_HANDLING
  19 #include "busybox.h"
  20
  21 static const struct suffix_mult dd_suffixes[] = {
  22         { "c", 1 },
  23         { "w", 2 },
  24         { "b", 512 },
  25         { "kD", 1000 },
  26         { "k", 1024 },
  27         { "MD", 1000000 },
  28         { "M", 1048576 },
  29         { "GD", 1000000000 },
  30         { "G", 1073741824 },
  31         { NULL, 0 }
  32 };
  33
  34 static size_t out_full;
  35 static size_t out_part;
  36 static size_t in_full;
  37 static size_t in_part;
  38
  39 static void dd_output_status(int cur_signal)
  40 {
  41         fprintf(stderr, "%ld+%ld records in\n%ld+%ld records out\n",
  42                         (long)in_full, (long)in_part,
  43                         (long)out_full, (long)out_part);
  44 }
  45
  46 int dd_main(int argc, char **argv)
  47 {
  48         size_t count = -1, oc = 0, ibs = 512, obs = 512;
  49         ssize_t n;
  50         off_t seek = 0, skip = 0;
  51         int sync_flag = FALSE, noerror = FALSE, trunc_flag = TRUE, twobufs_flag = 0,
  52                 oflag, ifd, ofd, i;
  53         const char *infile = NULL, *outfile = NULL;
  54         char *ibuf, *obuf;
  55
  56         if (ENABLE_FEATURE_DD_SIGNAL_HANDLING)
  57         {
  58                 struct sigaction sa;
  59
  60                 memset(&sa, 0, sizeof(sa));
  61                 sa.sa_handler = dd_output_status;
  62                 sa.sa_flags = SA_RESTART;
  63                 sigemptyset(&sa.sa_mask);
  64                 sigaction(SIGUSR1, &sa, 0);
  65         }
  66
  67         for (i = 1; i < argc; i++) {
  68                 if (ENABLE_FEATURE_DD_IBS_OBS && !strncmp("ibs=", argv[i], 4)) {
  69                         ibs = bb_xparse_number(argv[i]+4, dd_suffixes);
  70                         twobufs_flag++;
  71                 } else if (ENABLE_FEATURE_DD_IBS_OBS && !strncmp("obs=", argv[i], 4)) {
  72                         obs = bb_xparse_number(argv[i]+4, dd_suffixes);
  73                         twobufs_flag++;
  74                 } else if (!strncmp("bs=", argv[i], 3)) {
  75                         ibs = obs = bb_xparse_number(argv[i]+3, dd_suffixes);
  76                 } else if (!strncmp("count=", argv[i], 6))
  77                         count = bb_xparse_number(argv[i]+6, dd_suffixes);
  78                 else if (!strncmp("seek=", argv[i], 5))
  79                         seek = bb_xparse_number(argv[i]+5, dd_suffixes);
  80                 else if (!strncmp("skip=", argv[i], 5))
  81                         skip = bb_xparse_number(argv[i]+5, dd_suffixes);
  82                 else if (!strncmp("if=", argv[i], 3))
  83                         infile = argv[i]+3;
  84                 else if (!strncmp("of=", argv[i], 3))
  85                         outfile = argv[i]+3;
  86                 else if (ENABLE_FEATURE_DD_IBS_OBS && !strncmp("conv=", argv[i], 5)) {
  87                         ibuf = argv[i]+5;
  88                         while (1) {
  89                                 if (!strncmp("notrunc", ibuf, 7)) {
  90                                         trunc_flag = FALSE;
  91                                         ibuf += 7;
  92                                 } else if (!strncmp("sync", ibuf, 4)) {
  93                                         sync_flag = TRUE;
  94                                         ibuf += 4;
  95                                 } else if (!strncmp("noerror", ibuf, 7)) {
  96                                         noerror = TRUE;
  97                                         ibuf += 7;
  98                                 } else {
  99                                         bb_error_msg_and_die(bb_msg_invalid_arg, argv[i]+5, "conv");
 100                                 }
 101                                 if (ibuf[0] == '\0') break;
 102                                 if (ibuf[0] == ',') ibuf++;
 103                         }
 104                 } else
 105                         bb_show_usage();
 106         }
 107         ibuf = xmalloc(ibs);
 108
 109         if (twobufs_flag) obuf = xmalloc(obs);
 110         else obuf = ibuf;
 111
 112         if (infile != NULL) {
 113                 ifd = bb_xopen(infile, O_RDONLY);
 114         } else {
 115                 ifd = STDIN_FILENO;
 116                 infile = bb_msg_standard_input;
 117         }
 118
 119         if (outfile != NULL) {
 120                 oflag = O_WRONLY | O_CREAT;
 121
 122                 if (!seek && trunc_flag) {
 123                         oflag |= O_TRUNC;
 124                 }
 125
 126                 ofd = bb_xopen3(outfile, oflag, 0666);
 127
 128                 if (seek && trunc_flag) {
 129                         if (ftruncate(ofd, seek * obs) < 0) {
 130                                 struct stat st;
 131
 132                                 if (fstat (ofd, &st) < 0 || S_ISREG (st.st_mode) ||
 133                                                 S_ISDIR (st.st_mode)) {
 134                                         bb_perror_msg_and_die("%s", outfile);
 135                                 }
 136                         }
 137                 }
 138         } else {
 139                 ofd = STDOUT_FILENO;
 140                 outfile = bb_msg_standard_output;
 141         }
 142
 143         if (skip) {
 144                 if (lseek(ifd, skip * ibs, SEEK_CUR) < 0) {
 145                         while (skip-- > 0) {
 146                                 n = safe_read(ifd, ibuf, ibs);
 147                                 if (n < 0)
 148                                         bb_perror_msg_and_die("%s", infile);
 149                                 if (n == 0)
 150                                         break;
 151                         }
 152                 }
 153         }
 154
 155         if (seek) {
 156                 if (lseek(ofd, seek * obs, SEEK_CUR) < 0) {
 157                         bb_perror_msg_and_die("%s", outfile);
 158                 }
 159         }
 160
 161         while (in_full + in_part != count) {
 162                 if (noerror) {
 163                         /* Pre-zero the buffer when doing the noerror thing */
 164                         memset(ibuf, '\0', ibs);
 165                 }
 166
 167                 n = safe_read(ifd, ibuf, ibs);
 168                 if (n == 0) {
 169                         break;
 170                 }
 171                 if (n < 0) {
 172                         if (noerror) {
 173                                 n = ibs;
 174                                 bb_perror_msg("%s", infile);
 175                         } else {
 176                                 bb_perror_msg_and_die("%s", infile);
 177                         }
 178                 }
 179                 if ((size_t)n == ibs) {
 180                         in_full++;
 181                 } else {
 182                         in_part++;
 183                         if (sync_flag) {
 184                                 memset(ibuf + n, '\0', ibs - n);
 185                                 n = ibs;
 186                         }
 187                 }
 188                 if (twobufs_flag) {
 189                         char *tmp = ibuf;
 190                         while (n) {
 191                                 size_t d = obs - oc;
 192
 193                                 if (d > n) d = n;
 194                                 memcpy(obuf + oc, tmp, d);
 195                                 n -= d;
 196                                 tmp += d;
 197                                 oc += d;
 198                                 if (oc == obs) {
 199                                         if (bb_full_write(ofd, obuf, obs) < 0) {
 200                                                 bb_perror_msg_and_die("%s", outfile);
 201                                         }
 202                                         out_full++;
 203                                         oc = 0;
 204                                 }
 205                         }
 206                 } else {
 207                         if ((n = bb_full_write(ofd, ibuf, n)) < 0) {
 208                                 bb_perror_msg_and_die("%s", outfile);
 209                         }
 210                         if (n == ibs) out_full++;
 211                         else out_part++;
 212                 }
 213         }
 214
 215         if (ENABLE_FEATURE_DD_IBS_OBS && oc) {
 216                 if (bb_full_write(ofd, obuf, oc) < 0) {
 217                         bb_perror_msg_and_die("%s", outfile);
 218                 }
 219                 out_part++;
 220         }
 221         if (close (ifd) < 0) {
 222                 bb_perror_msg_and_die("%s", infile);
 223         }
 224
 225         if (close (ofd) < 0) {
 226                 bb_perror_msg_and_die("%s", outfile);
 227         }
 228
 229         dd_output_status(0);
 230
 231         return EXIT_SUCCESS;
 232 }