dd.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * Mini dd implementation for busybox
   4  *
   5  * Copyright (C) 1999 by Lineo, inc.
   6  * Written by Erik Andersen <andersen@lineo.com>, <andersee@debian.org>
   7  * based in part on code taken from sash.
   8  *
   9  * Copyright (c) 1999 by David I. Bell
  10  * Permission is granted to use, distribute, or modify this source,
  11  * provided that this copyright notice remains intact.
  12  *
  13  * Permission to distribute this code under the GPL has been granted.
  14  *
  15  * This program is free software; you can redistribute it and/or modify
  16  * it under the terms of the GNU General Public License as published by
  17  * the Free Software Foundation; either version 2 of the License, or
  18  * (at your option) any later version.
  19  *
  20  * This program is distributed in the hope that it will be useful,
  21  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  22  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  23  * General Public License for more details.
  24  *
  25  * You should have received a copy of the GNU General Public License
  26  * along with this program; if not, write to the Free Software
  27  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  28  *
  29  */
  30
  31
  32 #include "internal.h"
  33 #include <features.h>
  34 #include <stdio.h>
  35 #include <fcntl.h>
  36 #include <errno.h>
  37 #if (__GLIBC__ >= 2) && (__GLIBC_MINOR__ >= 1)
  38 #include <inttypes.h>
  39 #else
  40 typedef unsigned long long int uintmax_t;
  41 #endif
  42
  43 static const char dd_usage[] =
  44         "dd [if=name] [of=name] [bs=n] [count=n] [skip=n] [seek=n]\n\n"
  45         "Copy a file, converting and formatting according to options\n\n"
  46         "\tif=FILE\tread from FILE instead of stdin\n"
  47         "\tof=FILE\twrite to FILE instead of stdout\n"
  48         "\tbs=n\tread and write n bytes at a time\n"
  49         "\tcount=n\tcopy only n input blocks\n"
  50         "\tskip=n\tskip n input blocks\n"
  51         "\tseek=n\tskip n output blocks\n"
  52
  53         "\n"
  54         "Numbers may be suffixed by w (x2), k (x1024), b (x512), or M (x1024^2)\n";
  55
  56
  57
  58 extern int dd_main(int argc, char **argv)
  59 {
  60         const char *inFile = NULL;
  61         const char *outFile = NULL;
  62         char *cp;
  63         int inFd;
  64         int outFd;
  65         int inCc = 0;
  66         int outCc;
  67         long blockSize = 512;
  68         uintmax_t skipBlocks = 0;
  69         uintmax_t seekBlocks = 0;
  70         uintmax_t count = (uintmax_t) - 1;
  71         uintmax_t intotal;
  72         uintmax_t outTotal;
  73         unsigned char *buf;
  74
  75         argc--;
  76         argv++;
  77
  78         /* Parse any options */
  79         while (argc) {
  80                 if (inFile == NULL && (strncmp(*argv, "if", 2) == 0))
  81                         inFile = ((strchr(*argv, '=')) + 1);
  82                 else if (outFile == NULL && (strncmp(*argv, "of", 2) == 0))
  83                         outFile = ((strchr(*argv, '=')) + 1);
  84                 else if (strncmp("count", *argv, 5) == 0) {
  85                         count = getNum((strchr(*argv, '=')) + 1);
  86                         if (count <= 0) {
  87                                 fprintf(stderr, "Bad count value %s\n", *argv);
  88                                 goto usage;
  89                         }
  90                 } else if (strncmp(*argv, "bs", 2) == 0) {
  91                         blockSize = getNum((strchr(*argv, '=')) + 1);
  92                         if (blockSize <= 0) {
  93                                 fprintf(stderr, "Bad block size value %s\n", *argv);
  94                                 goto usage;
  95                         }
  96                 } else if (strncmp(*argv, "skip", 4) == 0) {
  97                         skipBlocks = getNum((strchr(*argv, '=')) + 1);
  98                         if (skipBlocks <= 0) {
  99                                 fprintf(stderr, "Bad skip value %s\n", *argv);
 100                                 goto usage;
 101                         }
 102
 103                 } else if (strncmp(*argv, "seek", 4) == 0) {
 104                         seekBlocks = getNum((strchr(*argv, '=')) + 1);
 105                         if (seekBlocks <= 0) {
 106                                 fprintf(stderr, "Bad seek value %s\n", *argv);
 107                                 goto usage;
 108                         }
 109
 110                 } else {
 111                         goto usage;
 112                 }
 113                 argc--;
 114                 argv++;
 115         }
 116
 117         buf = malloc(blockSize);
 118         if (buf == NULL) {
 119                 fprintf(stderr, "Cannot allocate buffer\n");
 120                 exit(FALSE);
 121         }
 122
 123         intotal = 0;
 124         outTotal = 0;
 125
 126         if (inFile == NULL)
 127                 inFd = fileno(stdin);
 128         else
 129                 inFd = open(inFile, 0);
 130
 131         if (inFd < 0) {
 132                 perror(inFile);
 133                 free(buf);
 134                 exit(FALSE);
 135         }
 136
 137         if (outFile == NULL)
 138                 outFd = fileno(stdout);
 139         else
 140                 outFd = open(outFile, O_WRONLY | O_CREAT | O_TRUNC, 0666);
 141
 142         if (outFd < 0) {
 143                 perror(outFile);
 144                 close(inFd);
 145                 free(buf);
 146                 exit(FALSE);
 147         }
 148
 149         lseek(inFd, skipBlocks * blockSize, SEEK_SET);
 150         lseek(outFd, seekBlocks * blockSize, SEEK_SET);
 151         //
 152         //TODO: Convert to using fullRead & fullWrite
 153         // from utility.c
 154         //  -Erik
 155         while (outTotal < count * blockSize) {
 156                 inCc = read(inFd, buf, blockSize);
 157                 if (inCc < 0) {
 158                         perror(inFile);
 159                         goto cleanup;
 160                 } else if (inCc == 0) {
 161                         goto cleanup;
 162                 }
 163                 intotal += inCc;
 164                 cp = buf;
 165
 166                 while (intotal > outTotal) {
 167                         if (outTotal + inCc > count * blockSize)
 168                                 inCc = count * blockSize - outTotal;
 169                         outCc = write(outFd, cp, inCc);
 170                         if (outCc < 0) {
 171                                 perror(outFile);
 172                                 goto cleanup;
 173                         } else if (outCc == 0) {
 174                                 goto cleanup;
 175                         }
 176
 177                         inCc -= outCc;
 178                         cp += outCc;
 179                         outTotal += outCc;
 180                 }
 181         }
 182
 183         if (inCc < 0)
 184                 perror(inFile);
 185
 186   cleanup:
 187         close(inFd);
 188         close(outFd);
 189         free(buf);
 190
 191         printf("%ld+%d records in\n", (long) (intotal / blockSize),
 192                    (intotal % blockSize) != 0);
 193         printf("%ld+%d records out\n", (long) (outTotal / blockSize),
 194                    (outTotal % blockSize) != 0);
 195         exit(TRUE);
 196   usage:
 197
 198         usage(dd_usage);
 199 }