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  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16  * General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  21  *
  22  */
  23
  24 #include <sys/types.h>
  25 #include <sys/stat.h>
  26 #include <stdlib.h>
  27 #include <stdio.h>
  28 #include <unistd.h>
  29 #include <string.h>
  30 #include <fcntl.h>
  31 #include "busybox.h"
  32
  33
  34 static const struct suffix_mult dd_suffixes[] = {
  35         { "c", 1 },
  36         { "w", 2 },
  37         { "b", 512 },
  38         { "kD", 1000 },
  39         { "k", 1024 },
  40         { "MD", 1000000 },
  41         { "M", 1048576 },
  42         { "GD", 1000000000 },
  43         { "G", 1073741824 },
  44         { NULL, 0 }
  45 };
  46
  47 int dd_main(int argc, char **argv)
  48 {
  49         size_t out_full = 0;
  50         size_t out_part = 0;
  51         size_t in_full = 0;
  52         size_t in_part = 0;
  53         size_t count = -1;
  54         size_t bs = 512;
  55         ssize_t n;
  56         off_t seek = 0;
  57         off_t skip = 0;
  58         int sync_flag = FALSE;
  59         int noerror = FALSE;
  60         int trunc_flag = TRUE;
  61         int oflag;
  62         int ifd;
  63         int ofd;
  64         int i;
  65         const char *infile = NULL;
  66         const char *outfile = NULL;
  67         char *buf;
  68
  69         for (i = 1; i < argc; i++) {
  70                 if (strncmp("bs=", argv[i], 3) == 0)
  71                         bs = bb_xparse_number(argv[i]+3, dd_suffixes);
  72                 else if (strncmp("count=", argv[i], 6) == 0)
  73                         count = bb_xparse_number(argv[i]+6, dd_suffixes);
  74                 else if (strncmp("seek=", argv[i], 5) == 0)
  75                         seek = bb_xparse_number(argv[i]+5, dd_suffixes);
  76                 else if (strncmp("skip=", argv[i], 5) == 0)
  77                         skip = bb_xparse_number(argv[i]+5, dd_suffixes);
  78                 else if (strncmp("if=", argv[i], 3) == 0)
  79                         infile = argv[i]+3;
  80                 else if (strncmp("of=", argv[i], 3) == 0)
  81                         outfile = argv[i]+3;
  82                 else if (strncmp("conv=", argv[i], 5) == 0) {
  83                         buf = argv[i]+5;
  84                         while (1) {
  85                                 if (strncmp("notrunc", buf, 7) == 0) {
  86                                         trunc_flag = FALSE;
  87                                         buf += 7;
  88                                 } else if (strncmp("sync", buf, 4) == 0) {
  89                                         sync_flag = TRUE;
  90                                         buf += 4;
  91                                 } else if (strncmp("noerror", buf, 7) == 0) {
  92                                         noerror = TRUE;
  93                                         buf += 7;
  94                                 } else {
  95                                         bb_error_msg_and_die("invalid conversion `%s'", argv[i]+5);
  96                                 }
  97                                 if (buf[0] == '\0')
  98                                         break;
  99                                 if (buf[0] == ',')
 100                                         buf++;
 101                         }
 102                 } else
 103                         bb_show_usage();
 104         }
 105
 106         buf = xmalloc(bs);
 107
 108         if (infile != NULL) {
 109                 ifd = bb_xopen(infile, O_RDONLY);
 110         } else {
 111                 ifd = STDIN_FILENO;
 112                 infile = bb_msg_standard_input;
 113         }
 114
 115         if (outfile != NULL) {
 116                 oflag = O_WRONLY | O_CREAT;
 117
 118                 if (!seek && trunc_flag) {
 119                         oflag |= O_TRUNC;
 120                 }
 121
 122                 if ((ofd = open(outfile, oflag, 0666)) < 0) {
 123                         bb_perror_msg_and_die("%s", outfile);
 124                 }
 125
 126                 if (seek && trunc_flag) {
 127                         if (ftruncate(ofd, seek * bs) < 0) {
 128                                 struct stat st;
 129
 130                                 if (fstat (ofd, &st) < 0 || S_ISREG (st.st_mode) ||
 131                                                 S_ISDIR (st.st_mode)) {
 132                                         bb_perror_msg_and_die("%s", outfile);
 133                                 }
 134                         }
 135                 }
 136         } else {
 137                 ofd = STDOUT_FILENO;
 138                 outfile = bb_msg_standard_output;
 139         }
 140
 141         if (skip) {
 142                 if (lseek(ifd, skip * bs, SEEK_CUR) < 0) {
 143                         bb_perror_msg_and_die("%s", infile);
 144                 }
 145         }
 146
 147         if (seek) {
 148                 if (lseek(ofd, seek * bs, 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(buf, '\0', bs);
 157                 }
 158                 n = safe_read(ifd, buf, bs);
 159                 if (n < 0) {
 160                         if (noerror) {
 161                                 n = bs;
 162                                 bb_perror_msg("%s", infile);
 163                         } else {
 164                                 bb_perror_msg_and_die("%s", infile);
 165                         }
 166                 }
 167                 if (n == 0) {
 168                         break;
 169                 }
 170                 if ((size_t)n == bs) {
 171                         in_full++;
 172                 } else {
 173                         in_part++;
 174                 }
 175                 if (sync_flag) {
 176                         memset(buf + n, '\0', bs - n);
 177                         n = bs;
 178                 }
 179                 n = bb_full_write(ofd, buf, n);
 180                 if (n < 0) {
 181                         bb_perror_msg_and_die("%s", outfile);
 182                 }
 183                 if ((size_t)n == bs) {
 184                         out_full++;
 185                 } else {
 186                         out_part++;
 187                 }
 188         }
 189
 190         if (close (ifd) < 0) {
 191                 bb_perror_msg_and_die("%s", infile);
 192         }
 193
 194         if (close (ofd) < 0) {
 195                 bb_perror_msg_and_die("%s", outfile);
 196         }
 197
 198         fprintf(stderr, "%ld+%ld records in\n%ld+%ld records out\n",
 199                         (long)in_full, (long)in_part,
 200                         (long)out_full, (long)out_part);
 201
 202         return EXIT_SUCCESS;
 203 }