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 = TRUE;
  61         int oflag;
  62         int ifd;
  63         int ofd;
  64         int i;
  65         char *infile = NULL;
  66         char *outfile = NULL;
  67         char *buf;
  68
  69         for (i = 1; i < argc; i++) {
  70                 if (strncmp("bs=", argv[i], 3) == 0)
  71                         bs = parse_number(argv[i]+3, dd_suffixes);
  72                 else if (strncmp("count=", argv[i], 6) == 0)
  73                         count = parse_number(argv[i]+6, dd_suffixes);
  74                 else if (strncmp("seek=", argv[i], 5) == 0)
  75                         seek = parse_number(argv[i]+5, dd_suffixes);
  76                 else if (strncmp("skip=", argv[i], 5) == 0)
  77                         skip = parse_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 = 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                                         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                         show_usage();
 104         }
 105
 106         buf = xmalloc(bs);
 107
 108         if (infile != NULL) {
 109                 if ((ifd = open(infile, O_RDONLY)) < 0) {
 110                         perror_msg_and_die("%s", infile);
 111                 }
 112         } else {
 113                 ifd = STDIN_FILENO;
 114                 infile = "standard input";
 115         }
 116
 117         if (outfile != NULL) {
 118                 oflag = O_WRONLY | O_CREAT;
 119
 120                 if (!seek && trunc) {
 121                         oflag |= O_TRUNC;
 122                 }
 123
 124                 if ((ofd = open(outfile, oflag, 0666)) < 0) {
 125                         perror_msg_and_die("%s", outfile);
 126                 }
 127
 128                 if (seek && trunc) {
 129                         if (ftruncate(ofd, seek * bs) < 0) {
 130                                 struct stat st;
 131
 132                                 if (fstat (ofd, &st) < 0 || S_ISREG (st.st_mode) ||
 133                                                 S_ISDIR (st.st_mode)) {
 134                                         perror_msg_and_die("%s", outfile);
 135                                 }
 136                         }
 137                 }
 138         } else {
 139                 ofd = STDOUT_FILENO;
 140                 outfile = "standard output";
 141         }
 142
 143         if (skip) {
 144                 if (lseek(ifd, skip * bs, SEEK_CUR) < 0) {
 145                         perror_msg_and_die("%s", infile);
 146                 }
 147         }
 148
 149         if (seek) {
 150                 if (lseek(ofd, seek * bs, SEEK_CUR) < 0) {
 151                         perror_msg_and_die("%s", outfile);
 152                 }
 153         }
 154
 155         while (in_full + in_part != count) {
 156                 if (noerror) {
 157                         /* Pre-zero the buffer when doing the noerror thing */
 158                         memset(buf, '\0', bs);
 159                 }
 160                 n = safe_read(ifd, buf, bs);
 161                 if (n < 0) {
 162                         if (noerror) {
 163                                 n = bs;
 164                                 perror_msg("%s", infile);
 165                         } else {
 166                                 perror_msg_and_die("%s", infile);
 167                         }
 168                 }
 169                 if (n == 0) {
 170                         break;
 171                 }
 172                 if (n == bs) {
 173                         in_full++;
 174                 } else {
 175                         in_part++;
 176                 }
 177                 if (sync_flag) {
 178                         memset(buf + n, '\0', bs - n);
 179                         n = bs;
 180                 }
 181                 n = full_write(ofd, buf, n);
 182                 if (n < 0) {
 183                         perror_msg_and_die("%s", outfile);
 184                 }
 185                 if (n == bs) {
 186                         out_full++;
 187                 } else {
 188                         out_part++;
 189                 }
 190         }
 191
 192         if (close (ifd) < 0) {
 193                 perror_msg_and_die("%s", infile);
 194         }
 195
 196         if (close (ofd) < 0) {
 197                 perror_msg_and_die("%s", outfile);
 198         }
 199
 200         fprintf(stderr, "%ld+%ld records in\n", (long)in_full, (long)in_part);
 201         fprintf(stderr, "%ld+%ld records out\n", (long)out_full, (long)out_part);
 202
 203         return EXIT_SUCCESS;
 204 }