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[PATCH] Don't error out writing a multibyte character to an unbuffered stream (bug 17522)
- From: Andreas Schwab <schwab at suse dot de>
- To: libc-alpha at sourceware dot org
- Date: Thu, 30 Oct 2014 12:35:02 +0100
- Subject: [PATCH] Don't error out writing a multibyte character to an unbuffered stream (bug 17522)
- Authentication-results: sourceware.org; auth=none
An unbuffered stream uses the _shortbuf[1] member of FILE as the buffer,
but code conversion may need up to MB_LEN_MAX bytes.
Andreas.
[BZ #17522]
* libio/wfileops.c (_IO_wdo_write): If the file buffer has room
for less than MB_LEN_MAX use a local buffer of that size.
* libio/tst-fputws.c: New file.
* libio/Makefile (tests): Add tst-fputws.
---
libio/Makefile | 2 +-
libio/tst-fputws.c | 39 +++++++++++++++++++++++++++++++++++++++
libio/wfileops.c | 25 ++++++++++++++++++++-----
3 files changed, 60 insertions(+), 6 deletions(-)
create mode 100644 libio/tst-fputws.c
diff --git a/libio/Makefile b/libio/Makefile
index 56952ce..2742128 100644
--- a/libio/Makefile
+++ b/libio/Makefile
@@ -61,7 +61,7 @@ tests = tst_swprintf tst_wprintf tst_swscanf tst_wscanf tst_getwc tst_putwc \
bug-memstream1 bug-wmemstream1 \
tst-setvbuf1 tst-popen1 tst-fgetwc bug-wsetpos tst-fseek \
tst-fwrite-error tst-ftell-partial-wide tst-ftell-active-handler \
- tst-ftell-append
+ tst-ftell-append tst-fputws
ifeq (yes,$(build-shared))
# Add test-fopenloc only if shared library is enabled since it depends on
# shared localedata objects.
diff --git a/libio/tst-fputws.c b/libio/tst-fputws.c
new file mode 100644
index 0000000..09f53df
--- /dev/null
+++ b/libio/tst-fputws.c
@@ -0,0 +1,39 @@
+/* Test that we can write a multibyte character to an unbuffered stream.
+ Copyright (C) 2014 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+#include <locale.h>
+#include <stdio.h>
+#include <wchar.h>
+
+static int
+do_test (void)
+{
+ const wchar_t str[] = L"\xbe\n";
+
+ setlocale (LC_ALL, "en_US.UTF-8");
+ setvbuf (stdout, NULL, _IONBF, 0);
+
+ if (fputws (str, stdout) < 0)
+ return 1;
+
+ return 0;
+}
+
+#define TEST_FUNCTION do_test ()
+
+#include <test-skeleton.c>
diff --git a/libio/wfileops.c b/libio/wfileops.c
index c5ec5f7..6a088b1 100644
--- a/libio/wfileops.c
+++ b/libio/wfileops.c
@@ -75,17 +75,32 @@ _IO_wdo_write (fp, data, to_do)
{
enum __codecvt_result result;
const wchar_t *new_data;
+ char mb_buf[MB_LEN_MAX];
+ char *write_base, *write_ptr, *buf_end;
+
+ if (fp->_IO_write_ptr - fp->_IO_write_base < sizeof (mb_buf))
+ {
+ /* Make sure we have room for at least one multibyte
+ character. */
+ write_ptr = write_base = mb_buf;
+ buf_end = mb_buf + sizeof (mb_buf);
+ }
+ else
+ {
+ write_ptr = fp->_IO_write_ptr;
+ write_base = fp->_IO_write_base;
+ buf_end = fp->_IO_buf_end;
+ }
/* Now convert from the internal format into the external buffer. */
result = (*cc->__codecvt_do_out) (cc, &fp->_wide_data->_IO_state,
data, data + to_do, &new_data,
- fp->_IO_write_ptr,
- fp->_IO_buf_end,
- &fp->_IO_write_ptr);
+ write_ptr,
+ buf_end,
+ &write_ptr);
/* Write out what we produced so far. */
- if (_IO_new_do_write (fp, fp->_IO_write_base,
- fp->_IO_write_ptr - fp->_IO_write_base) == EOF)
+ if (_IO_new_do_write (fp, write_base, write_ptr - write_base) == EOF)
/* Something went wrong. */
return WEOF;
--
2.1.3
--
Andreas Schwab, SUSE Labs, schwab@suse.de
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE 1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."