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/*
* Mini dd implementation for busybox
*
* Copyright (C) 1999 by Lineo, inc.
* Written by Erik Andersen <andersen@lineo.com>, <andersee@debian.org>
* based in part on code taken from sash.
*
* Copyright (c) 1999 by David I. Bell
* Permission is granted to use, distribute, or modify this source,
* provided that this copyright notice remains intact.
*
* Permission to distribute this code under the GPL has been granted.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/
#include "internal.h"
#include <stdio.h>
#include <fcntl.h>
#include <errno.h>
static const char dd_usage[] =
"dd [if=name] [of=name] [bs=n] [count=n]\n"
"Copy a file, converting and formatting according to options\n\n"
"\tif=FILE\tread from FILE instead of stdin\n"
"\tof=FILE\twrite to FILE instead of stout\n"
"\tbs=n\tread and write N BYTES at a time\n"
"\tcount=n\tcopy only n input blocks\n"
//"\tskip=n\tskip n input blocks\n"
"\n"
"BYTES may be suffixed: by k for x1024, b for x512, and w for x2.\n";
/*
* Read a number with a possible multiplier.
* Returns -1 if the number format is illegal.
*/
static long getNum (const char *cp)
{
long value;
if (!isDecimal (*cp))
return -1;
value = 0;
while (isDecimal (*cp))
value = value * 10 + *cp++ - '0';
switch (*cp++) {
case 'k':
value *= 1024;
break;
case 'b':
value *= 512;
break;
case 'w':
value *= 2;
break;
case '\0':
return value;
default:
return -1;
}
if (*cp)
return -1;
return value;
}
extern int dd_main (int argc, char **argv)
{
const char *inFile;
const char *outFile;
char *cp;
int inFd;
int outFd;
int inCc = 0;
int outCc;
int skipBlocks;
int blockSize;
long count;
long intotal;
long outTotal;
unsigned char *buf;
inFile = NULL;
outFile = NULL;
blockSize = 512;
skipBlocks = 0;
count = 1;
argc--;
argv++;
/* Parse any options */
while (argc) {
if (inFile == NULL && (strncmp(*argv, "if", 2) == 0))
inFile=((strchr(*argv, '='))+1);
else if (outFile == NULL && (strncmp(*argv, "of", 2) == 0))
outFile=((strchr(*argv, '='))+1);
else if (strncmp("count", *argv, 5) == 0) {
count = getNum ((strchr(*argv, '='))+1);
if (count <= 0) {
fprintf (stderr, "Bad count value %ld\n", count);
goto usage;
}
}
else if (strncmp(*argv, "bs", 2) == 0) {
blockSize = getNum ((strchr(*argv, '='))+1);
if (blockSize <= 0) {
fprintf (stderr, "Bad block size value %d\n", blockSize);
goto usage;
}
}
#if 0
else if (strncmp(*argv, "skip", 4) == 0) {
skipBlocks = atoi( *argv);
if (skipBlocks <= 0) {
fprintf (stderr, "Bad skip value %d\n", skipBlocks);
goto usage;
}
}
#endif
else {
goto usage;
}
argc--;
argv++;
}
if ( inFile == NULL || outFile == NULL)
goto usage;
buf = malloc (blockSize);
if (buf == NULL) {
fprintf (stderr, "Cannot allocate buffer\n");
exit( FALSE);
}
intotal = 0;
outTotal = 0;
if (inFile == NULL)
inFd = STDIN;
else
inFd = open (inFile, 0);
if (inFd < 0) {
perror (inFile);
free (buf);
exit( FALSE);
}
if (outFile == NULL)
outFd = STDOUT;
else
outFd = creat (outFile, 0666);
if (outFd < 0) {
perror (outFile);
close (inFd);
free (buf);
exit( FALSE);
}
//lseek(inFd, skipBlocks*blockSize, SEEK_SET);
while (outTotal < count * blockSize) {
inCc = read (inFd, buf, blockSize);
if (inCc < 0) {
perror (inFile);
goto cleanup;
}
intotal += inCc;
cp = buf;
while (intotal > outTotal) {
if (outTotal + inCc > count * blockSize)
inCc = count * blockSize - outTotal;
outCc = write (outFd, cp, inCc);
if (outCc < 0) {
perror (outFile);
goto cleanup;
}
inCc -= outCc;
cp += outCc;
outTotal += outCc;
}
}
if (inCc < 0)
perror (inFile);
cleanup:
close (inFd);
close (outFd);
free (buf);
printf ("%ld+%d records in\n", intotal / blockSize,
(intotal % blockSize) != 0);
printf ("%ld+%d records out\n", outTotal / blockSize,
(outTotal % blockSize) != 0);
exit( TRUE);
usage:
fprintf (stderr, "%s", dd_usage);
exit( FALSE);
}
|
