--
-------------- next part --------------
#ifndef lint
static char *sccsid = "_at_(#)itc.c 4.1 (ULTRIX) 7/17/90";
#endif lint
/************************************************************************
* *
* Copyright (c) 1989 by *
* Digital Equipment Corporation, Maynard, MA *
* All rights reserved. *
* *
* This software is furnished under a license and may be used and *
* copied only in accordance with the terms of such license and *
* with the inclusion of the above copyright notice. This *
* software or any other copies thereof may not be provided or *
* otherwise made available to any other person. No title to and *
* ownership of the software is hereby transferred. *
* *
* The information in this software is subject to change without *
* notice and should not be construed as a commitment by Digital *
* Equipment Corporation. *
* *
* Digital assumes no responsibility for the use or reliability *
* of its software on equipment which is not supplied by Digital. *
* *
************************************************************************/
/*
* itc - image tape copy, tape to disk and back out
*
* itc i /dev/nrmt##{l,m,h} > file
* itc o /dev/nrmt##{l,m,h} < file
*
* This program serves as an example of how to use the Ultrix N-buffered
* I/O mechanism to buffer I/O requests to and from a tape device under
* Ultrix. The user interface for the N-buffered I/O mechanism is
* documented under nbuf(4) and works for any character device provided
* that the device driver for the device has all the same routines
* implemented and specified in the kernel file conf.c as do all the
* Ultrix tape drivers. The symbol "##" above represents a tape drive
* device unit number and the {l,m,h} is the density selection of
* "l"ow, "m"edium, or "h"igh where applicable.
*
* Digital Equipment Corporation supplies this software example on
* an "as-is" basis for general customer use. Note that Digital
* does not offer any support for it, nor is it covered under any
* of Digital's support contracts.
*
*/
#include <stdio.h>
#include <signal.h>
#include <sys/types.h>
#include <sys/errno.h>
#include <sys/file.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <sys/devio.h>
#include <sys/mtio.h>
#define BUFAMT 128*512-1 /* Zero based 64 KB */
#define NBUFAMT 8 /* Number of N-buffers */
extern int errno; /* Error number */
main(argc, argv)
int argc;
char **argv;
{
int opt; /* Options variable */
int fd; /* File descriptor */
int cnt = NBUFAMT; /* N-buffer count */
int n; /* Amount for I/O */
char *buf[NBUFAMT]; /* N-buffer array */
int eof; /* End-of-file flag */
int cnter = 0; /* Counter */
/* Check to be sure option was given */
if( argc < 3 ) {
fprintf( stderr,
"Usage:\t itc i /dev/nrmt##{l,m,h} > file\n\t itc o /dev/nrmt##{l,m,h} < file\n" );
exit( 1 );
}
/* Save the option */
opt = argv[1][0];
/* Check to see which option and open device */
if(( fd = open( argv[2], opt == 'i' ? 0 : 1 )) < 0 ) {
perror( "itc: tape open error" );
exit( 1 );
}
/* Determine if we can use n-buffered I/O */
if( ioctl( fd, FIONBUF, &cnt ) < 0 ) {
cnt = 0;
}
/* Allocate buffers if N-buffered I/O is possible */
if( cnt > 0 )
for( n=0; n < cnt; n++ )
buf[n] = (char *)malloc( BUFAMT+1024 );
else
buf[0] = (char *)malloc( BUFAMT );
/* Determine which way */
if( opt == 'i' ) {
/* Copying from tape to a file */
eof = 0;
for( ;; ) {
loop:
n = read( fd, buf[cnter], BUFAMT );
if( cnt ) {
int didread;
if( ++cnter == cnt ) {
cnter = 0;
}
errno = 0;
didread = ioctl( fd, FIONBDONE, &buf[cnter] );
if( errno != EINVAL ) {
n = didread;
} else {
goto loop;
}
}
if( n < 0 ) {
perror( "itc: tape read error" );
exit( 1 );
}
/* We encountered a tape mark */
/* Reset to next tape file */
if( n == 0 ) {
close( fd );
if( eof ) {
break;
} else {
eof = 1;
}
/* Skip to next tape file */
if(( fd = open( argv[2], opt == 'i' ? 0 : 1 )) < 0 ) {
perror( "itc: tape open error" );
exit( 1 );
}
if( cnt && ioctl( fd, FIONBUF, &cnt ) < 0 ) {
cnt = 0;
}
cnter = 0;
} else {
eof = 0;
}
write( 1, (char *)&n, sizeof( n ) );
if( n ) {
write( 1, buf[cnter], n );
}
}
} else {
int read_len;
/* Copying from file to tape */
while( read( 0, (char *)&n, sizeof( n )) == sizeof( n )) {
if( n == 0 ) {
close( fd );
fd = open( argv[2], 1 );
if( cnt && ioctl( fd, FIONBUF, &cnt ) < 0 ) {
cnt = 0;
}
cnter = 0;
} else {
int err;
if(( read_len = read( 0, buf[cnter], n )) != n ) {
perror( "itc: file format error" );
exit( 1 );
}
err = write( fd, buf[cnter], n );
if( cnt && ( err >= 0 )) {
int didwrite;
if( ++cnter == cnt ) {
cnter = 0;
}
errno = 0;
didwrite = ioctl( fd, FIONBDONE, &buf[cnter] );
if ( errno != EINVAL ) {
err = didwrite;
}
}
if( err < 0 ) {
perror( "itc: tape write error" );
exit( 1 );
}
}
}
close( fd );
}
}
Received on Mon Mar 18 2002 - 18:25:54 GMT
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