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/*
* lseek() - POSIX 1003.1b 6.5.3 - Reposition Read/Write File Offset
*
* COPYRIGHT (c) 1989-1999.
* On-Line Applications Research Corporation (OAR).
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
* http://www.rtems.com/license/LICENSE.
*
* $Id$
*/
#if HAVE_CONFIG_H
#include "config.h"
#endif
#include <unistd.h>
#include <rtems/libio_.h>
off_t lseek( int fd, off_t offset, int whence )
{
off_t rv = 0;
rtems_libio_t *iop;
off_t reference_offset;
off_t old_offset;
off_t new_offset;
rtems_libio_check_fd( fd );
iop = rtems_libio_iop( fd );
rtems_libio_check_is_open(iop);
old_offset = iop->offset;
switch ( whence ) {
case SEEK_SET:
reference_offset = 0;
break;
case SEEK_CUR:
reference_offset = old_offset;
break;
case SEEK_END:
reference_offset = iop->size;
break;
default:
errno = EINVAL;
rv = (off_t) -1;
break;
}
new_offset = reference_offset + offset;
if ( rv == 0 ) {
if (
(reference_offset >= 0 && new_offset >= offset)
|| (reference_offset < 0 && new_offset <= offset)
) {
switch ( rtems_filesystem_node_type( &iop->pathinfo ) ) {
case RTEMS_FILESYSTEM_DIRECTORY:
case RTEMS_FILESYSTEM_MEMORY_FILE:
if ( new_offset < 0 ) {
errno = EINVAL;
rv = (off_t) -1;
}
break;
default:
break;
}
if ( rv == 0 ) {
iop->offset = new_offset;
rv = (*iop->pathinfo.handlers->lseek_h)( iop, offset, whence );
if ( rv == (off_t) -1 ) {
iop->offset = old_offset;
}
}
} else {
errno = EOVERFLOW;
rv = (off_t) -1;
}
}
return rv;
}
/*
* _lseek_r
*
* This is the Newlib dependent reentrant version of lseek().
*/
#if defined(RTEMS_NEWLIB) && !defined(HAVE__LSEEK_R)
#include <reent.h>
off_t _lseek_r(
struct _reent *ptr __attribute__((unused)),
int fd,
off_t offset,
int whence
)
{
return lseek( fd, offset, whence );
}
#endif
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