mirror of
git://sourceware.org/git/glibc.git
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Xiang Gao
97bd3b3d56
setvbuf (stream, NULL, _IOFBF, 0) takes a special path in _IO_setvbuf: if the byte-oriented buffer base is NULL, it calls _IO_DOALLOCATE and returns without invoking the stream setbuf hook. For open_wmemstream, the byte-oriented buffer base is NULL although the wide result buffer has already been initialized in _wide_data. As a result, this path calls _IO_wdefault_doallocate, which may replace the wide buffer managed by open_wmemstream. Install an open_wmemstream-specific doallocate hook that leaves the growable result buffer unchanged. Add a regression test for this path. Install a narrow memstream doallocate hook as well. It keeps both memstream vtables consistent (generic stdio allocation must not replace the growable result buffer). Signed-off-by: Xiang Gao <gaoxiang@kylinos.cn> Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
132 lines
3.3 KiB
C
132 lines
3.3 KiB
C
/* Copyright (C) 1995-2026 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#include "libioP.h"
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#include "strfile.h"
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#include <stdio.h>
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#include <stdlib.h>
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struct _IO_FILE_memstream
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{
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_IO_strfile _sf;
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char **bufloc;
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size_t *sizeloc;
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};
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/* Open a stream that writes into a malloc'd buffer that is expanded as
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necessary. *BUFLOC and *SIZELOC are updated with the buffer's location
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and the number of characters written on fflush or fclose. */
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FILE *
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__open_memstream (char **bufloc, size_t *sizeloc)
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{
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struct locked_FILE
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{
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struct _IO_FILE_memstream fp;
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#ifdef _IO_MTSAFE_IO
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_IO_lock_t lock;
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#endif
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struct _IO_wide_data wd;
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} *new_f;
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char *buf;
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new_f = (struct locked_FILE *) malloc (sizeof (struct locked_FILE));
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if (new_f == NULL)
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return NULL;
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#ifdef _IO_MTSAFE_IO
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new_f->fp._sf._sbf._f._lock = &new_f->lock;
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#endif
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buf = calloc (1, BUFSIZ);
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if (buf == NULL)
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{
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free (new_f);
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return NULL;
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}
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_IO_init_internal (&new_f->fp._sf._sbf._f, 0);
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_IO_JUMPS_FILE_plus (&new_f->fp._sf._sbf) = &_IO_mem_jumps;
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_IO_str_init_static_internal (&new_f->fp._sf, buf, BUFSIZ, buf);
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new_f->fp._sf._sbf._f._flags &= ~_IO_USER_BUF;
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new_f->fp._sf._s._allocate_buffer_unused = (_IO_alloc_type) malloc;
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new_f->fp._sf._s._free_buffer_unused = (_IO_free_type) free;
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new_f->fp.bufloc = bufloc;
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new_f->fp.sizeloc = sizeloc;
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/* Disable single thread optimization. BZ 21735. */
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new_f->fp._sf._sbf._f._flags2 |= _IO_FLAGS2_NEED_LOCK;
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return (FILE *) &new_f->fp._sf._sbf;
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}
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libc_hidden_def (__open_memstream)
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weak_alias (__open_memstream, open_memstream)
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int
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_IO_mem_sync (FILE *fp)
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{
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struct _IO_FILE_memstream *mp = (struct _IO_FILE_memstream *) fp;
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if (fp->_IO_write_ptr == fp->_IO_write_end)
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{
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_IO_str_overflow (fp, '\0');
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--fp->_IO_write_ptr;
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}
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*mp->bufloc = fp->_IO_write_base;
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*mp->sizeloc = fp->_IO_write_ptr - fp->_IO_write_base;
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return 0;
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}
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void
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_IO_mem_finish (FILE *fp, int dummy)
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{
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struct _IO_FILE_memstream *mp = (struct _IO_FILE_memstream *) fp;
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*mp->bufloc = (char *) realloc (fp->_IO_write_base,
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fp->_IO_write_ptr - fp->_IO_write_base + 1);
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if (*mp->bufloc != NULL)
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{
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(*mp->bufloc)[fp->_IO_write_ptr - fp->_IO_write_base] = '\0';
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*mp->sizeloc = fp->_IO_write_ptr - fp->_IO_write_base;
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fp->_IO_buf_base = NULL;
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}
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_IO_str_finish (fp, 0);
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}
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FILE *
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_IO_mem_setbuf (FILE *fp, char *p, ssize_t len)
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{
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/* Memstream manage a growable buffer internally. */
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return fp;
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}
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int
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_IO_mem_doallocate (FILE *fp)
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{
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/* Memstream manage a growable buffer internally. The doallocate
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hook must not replace it with a generic stdio buffer. */
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return 1;
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}
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