99 lines
3.0 KiB
C
99 lines
3.0 KiB
C
/* Copyright (C) 1993-2022 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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As a special exception, if you link the code in this file with
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files compiled with a GNU compiler to produce an executable,
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that does not cause the resulting executable to be covered by
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the GNU Lesser General Public License. This exception does not
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however invalidate any other reasons why the executable file
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might be covered by the GNU Lesser General Public License.
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This exception applies to code released by its copyright holders
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in files containing the exception. */
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#include "libioP.h"
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#define _IOFBF 0 /* Fully buffered. */
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#define _IOLBF 1 /* Line buffered. */
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#define _IONBF 2 /* No buffering. */
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int
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_IO_setvbuf (FILE *fp, char *buf, int mode, size_t size)
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{
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int result;
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CHECK_FILE (fp, EOF);
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_IO_acquire_lock (fp);
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switch (mode)
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{
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case _IOFBF:
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fp->_flags &= ~(_IO_LINE_BUF|_IO_UNBUFFERED);
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if (buf == NULL)
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{
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if (fp->_IO_buf_base == NULL)
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{
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/* There is no flag to distinguish between "fully buffered
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mode has been explicitly set" as opposed to "line
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buffering has not been explicitly set". In both
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cases, _IO_LINE_BUF is off. If this is a tty, and
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_IO_filedoalloc later gets called, it cannot know if
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it should set the _IO_LINE_BUF flag (because that is
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the default), or not (because we have explicitly asked
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for fully buffered mode). So we make sure a buffer
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gets allocated now, and explicitly turn off line
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buffering.
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A possibly cleaner alternative would be to add an
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extra flag, but then flags are a finite resource. */
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if (_IO_DOALLOCATE (fp) < 0)
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{
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result = EOF;
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goto unlock_return;
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}
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fp->_flags &= ~_IO_LINE_BUF;
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}
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result = 0;
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goto unlock_return;
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}
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break;
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case _IOLBF:
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fp->_flags &= ~_IO_UNBUFFERED;
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fp->_flags |= _IO_LINE_BUF;
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if (buf == NULL)
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{
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result = 0;
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goto unlock_return;
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}
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break;
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case _IONBF:
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fp->_flags &= ~_IO_LINE_BUF;
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fp->_flags |= _IO_UNBUFFERED;
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buf = NULL;
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size = 0;
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break;
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default:
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result = EOF;
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goto unlock_return;
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}
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result = _IO_SETBUF (fp, buf, size) == NULL ? EOF : 0;
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unlock_return:
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_IO_release_lock (fp);
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return result;
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}
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libc_hidden_def (_IO_setvbuf)
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weak_alias (_IO_setvbuf, setvbuf)
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