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/**
* @file
*
* @brief RTEMS Default File System reposits the offset of the open file fd
* @ingroup LibIOFSOps File System Operations
*/
/*
* Copyright (c) 2012 embedded brains GmbH. All rights reserved.
*
* embedded brains GmbH
* Obere Lagerstr. 30
* 82178 Puchheim
* Germany
* <rtems@embedded-brains.de>
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
* http://www.rtems.org/license/LICENSE.
*/
#if HAVE_CONFIG_H
#include "config.h"
#endif
#include <rtems/libio_.h>
off_t rtems_filesystem_default_lseek_file(
rtems_libio_t *iop,
off_t offset,
int whence
)
{
off_t rv = 0;
off_t reference_offset;
struct stat st;
switch ( whence ) {
case SEEK_SET:
reference_offset = 0;
break;
case SEEK_CUR:
reference_offset = iop->offset;
break;
case SEEK_END:
st.st_size = 0;
rv = (*iop->pathinfo.handlers->fstat_h)( &iop->pathinfo, &st );
reference_offset = st.st_size;
break;
default:
errno = EINVAL;
rv = -1;
break;
}
if ( rv == 0 ) {
off_t new_offset = reference_offset + offset;
if (
(offset >= 0 && new_offset >= reference_offset)
|| (offset < 0 && new_offset < reference_offset)
) {
if ( new_offset >= 0 ) {
iop->offset = new_offset;
rv = new_offset;
} else {
errno = EINVAL;
rv = -1;
}
} else {
errno = EOVERFLOW;
rv = -1;
}
}
return rv;
}
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