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b0cb9f85ca
The _REENT_GLOBAL_STDIO_STREAMS was introduced by commit
668a4c8722090fffd10869dbb15b879651c1370d in 2017. Since then it was enabled by
default for RTEMS. Recently, the option was enabled for Cygwin which
previously used an alternative implementation to use global stdio streams.
In Newlib, the stdio streams are defined to thread-specific pointers
_reent::_stdin, _reent::_stdout and _reent::_stderr. If the option is disabled
(the default for most systems), then these pointers are initialized to
thread-specific FILE objects which use file descriptors 0, 1, and 2,
respectively. There are at least three problems with this:
(1) The thread-specific FILE objects are closed by _reclaim_reent(). This
leads to problems with language run-time libraries that provide wrappers to
the C/POSIX stdio streams (for example C++ and Ada), since they use the
thread-specific FILE objects of the initialization thread. In case the
initialization thread is deleted, then they use freed memory.
(2) Since thread-specific FILE objects are used with a common output device via
file descriptors 0, 1 and 2, the locking at FILE object level cannot ensure
atomicity of the output, e.g. a call to printf().
(3) There are resource managment issues, see:
https://sourceware.org/pipermail/newlib/2022/019558.html
https://bugs.linaro.org/show_bug.cgi?id=5841
This patch enables the _REENT_GLOBAL_STDIO_STREAMS behaviour for all Newlib
configurations and removes the option. This removes a couple of #ifdef blocks.
75 lines
1.9 KiB
C
75 lines
1.9 KiB
C
/*
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* Copyright (c) 1990 The Regents of the University of California.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms are permitted
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* provided that the above copyright notice and this paragraph are
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* duplicated in all such forms and that any documentation,
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* and/or other materials related to such
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* distribution and use acknowledge that the software was developed
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* by the University of California, Berkeley. The name of the
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* University may not be used to endorse or promote products derived
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* from this software without specific prior written permission.
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* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
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*/
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/*
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FUNCTION
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<<fcloseall>>---close all files
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INDEX
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fcloseall
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INDEX
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_fcloseall_r
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SYNOPSIS
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#include <stdio.h>
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int fcloseall(void);
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int _fcloseall_r (struct _reent *<[ptr]>);
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DESCRIPTION
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<<fcloseall>> closes all files in the current reentrancy struct's domain.
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The function <<_fcloseall_r>> is the same function, except the reentrancy
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struct is passed in as the <[ptr]> argument.
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This function is not recommended as it closes all streams, including
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the std streams.
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RETURNS
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<<fclose>> returns <<0>> if all closes are successful. Otherwise,
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EOF is returned.
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PORTABILITY
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<<fcloseall>> is a glibc extension.
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Required OS subroutines: <<close>>, <<fstat>>, <<isatty>>, <<lseek>>,
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<<read>>, <<sbrk>>, <<write>>.
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*/
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/* This file based upon fwalk.c. */
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#include <_ansi.h>
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#include <reent.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <errno.h>
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#include "local.h"
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int
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_fcloseall_r (struct _reent *ptr)
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{
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/* There are no thread-specific FILE objects */
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return 0;
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}
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#ifndef _REENT_ONLY
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int
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fcloseall (void)
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{
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return _fwalk_sglue (_GLOBAL_REENT, _fclose_r, &__sglue);
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}
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#endif
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