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Takashi Yano 3d94e07c49 newlib: libc: Fix crash on fprintf to a wide-oriented stream.
Previously, fprintf() on a wide-oriented stream crashes or outputs
garbage. This is because a narrow char string which can be odd bytes
in length is cast into a wide char string which should be even
bytes in length in __sprint_r/__sfputs_r based on the __SWID flag.
As a result, if the length is odd bytes, the reading buffer runs over
the buffer length, which causes a crash. If the length is even bytes,
garbage is printed.

With this patch, any output to the stream which is set to different
orientation fails with error just like glibc. Note that it behaves
differently from other libc implementations such as BSD, musl and
Solaris.

Reviewed-by: Corinna Vinschen <corinna@vinschen.de>
Signed-off-by: Takashi Yano <takashi.yano@nifty.ne.jp>
2023-11-10 00:36:41 +09:00

117 lines
3.2 KiB
C

/*
* Copyright (c) 1990 The Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms are permitted
* provided that the above copyright notice and this paragraph are
* duplicated in all such forms and that any documentation,
* and/or other materials related to such
* distribution and use acknowledge that the software was developed
* by the University of California, Berkeley. The name of the
* University may not be used to endorse or promote products derived
* from this software without specific prior written permission.
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*/
/*
FUNCTION
<<putc>>---write a character (macro)
INDEX
putc
INDEX
_putc_r
SYNOPSIS
#include <stdio.h>
int putc(int <[ch]>, FILE *<[fp]>);
#include <stdio.h>
int _putc_r(struct _reent *<[ptr]>, int <[ch]>, FILE *<[fp]>);
DESCRIPTION
<<putc>> is a macro, defined in <<stdio.h>>. <<putc>>
writes the argument <[ch]> to the file or stream identified by
<[fp]>, after converting it from an <<int>> to an <<unsigned char>>.
If the file was opened with append mode (or if the stream cannot
support positioning), then the new character goes at the end of the
file or stream. Otherwise, the new character is written at the
current value of the position indicator, and the position indicator
advances by one.
For a subroutine version of this macro, see <<fputc>>.
The <<_putc_r>> function is simply the reentrant version of
<<putc>> that takes an additional reentrant structure argument: <[ptr]>.
RETURNS
If successful, <<putc>> returns its argument <[ch]>. If an error
intervenes, the result is <<EOF>>. You can use `<<ferror(<[fp]>)>>' to
query for errors.
PORTABILITY
ANSI C requires <<putc>>; it suggests, but does not require, that
<<putc>> be implemented as a macro. The standard explicitly permits
macro implementations of <<putc>> to use the <[fp]> argument more than once;
therefore, in a portable program, you should not use an expression
with side effects as this argument.
Supporting OS subroutines required: <<close>>, <<fstat>>, <<isatty>>,
<<lseek>>, <<read>>, <<sbrk>>, <<write>>.
*/
#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "%W% (Berkeley) %G%";
#endif /* LIBC_SCCS and not lint */
#include <_ansi.h>
#include <stdio.h>
#include "local.h"
/*
* A subroutine version of the macro putc.
*/
#undef putc
int
_putc_r (struct _reent *ptr,
int c,
register FILE *fp)
{
int result;
CHECK_INIT (ptr, fp);
if (ORIENT (fp, -1) != -1)
return EOF;
_newlib_flockfile_start (fp);
result = __sputc_r (ptr, c, fp);
_newlib_flockfile_end (fp);
return result;
}
#ifndef _REENT_ONLY
int
putc (int c,
register FILE *fp)
{
#if !defined(PREFER_SIZE_OVER_SPEED) && !defined(__OPTIMIZE_SIZE__)
int result;
struct _reent *reent = _REENT;
CHECK_INIT (reent, fp);
if (ORIENT (fp, -1) != -1)
return EOF;
_newlib_flockfile_start (fp);
result = __sputc_r (reent, c, fp);
_newlib_flockfile_end (fp);
return result;
#else
return _putc_r (_REENT, c, fp);
#endif
}
#endif /* !_REENT_ONLY */