libcsupport/src/close.c

0001 /* SPDX-License-Identifier: BSD-2-Clause */
0002
0003 /**
0004  * @file
0005  *
0006  * @ingroup libcsupport
0007  *
0008  * @brief POSIX 1003.1b 6.3.1 - Close a File
0009  */
0010
0011 /*
0012  *  COPYRIGHT (c) 1989-1999.
0013  *  On-Line Applications Research Corporation (OAR).
0014  *
0015  * Redistribution and use in source and binary forms, with or without
0016  * modification, are permitted provided that the following conditions
0017  * are met:
0018  * 1. Redistributions of source code must retain the above copyright
0019  *    notice, this list of conditions and the following disclaimer.
0020  * 2. Redistributions in binary form must reproduce the above copyright
0021  *    notice, this list of conditions and the following disclaimer in the
0022  *    documentation and/or other materials provided with the distribution.
0023  *
0024  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
0025  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
0026  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
0027  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
0028  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
0029  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
0030  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
0031  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
0032  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
0033  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
0034  * POSSIBILITY OF SUCH DAMAGE.
0035  */
0036
0037 #ifdef HAVE_CONFIG_H
0038 #include "config.h"
0039 #endif
0040
0041 #include <rtems/libio_.h>
0042
0043 int close(
0044   int  fd
0045 )
0046 {
0047   rtems_libio_t *iop;
0048   unsigned int   flags;
0049   int            rc;
0050
0051   if ( (uint32_t) fd >= rtems_libio_number_iops ) {
0052     rtems_set_errno_and_return_minus_one( EBADF );
0053   }
0054
0055   iop = rtems_libio_iop( fd );
0056   flags = rtems_libio_iop_flags( iop );
0057
0058   while ( true ) {
0059     unsigned int desired;
0060     bool         success;
0061
0062     if ( ( flags & LIBIO_FLAGS_OPEN ) == 0 ) {
0063       rtems_set_errno_and_return_minus_one( EBADF );
0064     }
0065
0066     /* The expected flags */
0067     flags &= LIBIO_FLAGS_REFERENCE_INC - 1U;
0068
0069     desired = flags & ~LIBIO_FLAGS_OPEN;
0070     success = _Atomic_Compare_exchange_uint(
0071       &iop->flags,
0072       &flags,
0073       desired,
0074       ATOMIC_ORDER_ACQ_REL,
0075       ATOMIC_ORDER_RELAXED
0076     );
0077
0078     if ( success ) {
0079       break;
0080     }
0081
0082     if ( ( flags & ~( LIBIO_FLAGS_REFERENCE_INC - 1U ) ) != 0 ) {
0083       rtems_set_errno_and_return_minus_one( EBUSY );
0084     }
0085   }
0086
0087   rc = (*iop->pathinfo.handlers->close_h)( iop );
0088
0089   rtems_libio_free( iop );
0090
0091   return rc;
0092 }
0093
0094 /*
0095  *  _close_r
0096  *
0097  *  This is the Newlib dependent reentrant version of close().
0098  */
0099
0100 #if defined(RTEMS_NEWLIB) && !defined(HAVE__CLOSE_R)
0101
0102 #include <reent.h>
0103
0104 int _close_r(
0105   struct _reent *ptr RTEMS_UNUSED,
0106   int            fd
0107 )
0108 {
0109   return close( fd );
0110 }
0111 #endif