61 lines
2.2 KiB
C
61 lines
2.2 KiB
C
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/* 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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#include <stdio.h>
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#include <sys/param.h>
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char *
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__fgets_chk (char *buf, size_t size, int n, FILE *fp)
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{
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size_t count;
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char *result;
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CHECK_FILE (fp, NULL);
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if (n <= 0)
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return NULL;
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_IO_acquire_lock (fp);
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/* This is very tricky since a file descriptor may be in the
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non-blocking mode. The error flag doesn't mean much in this
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case. We return an error only when there is a new error. */
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int old_error = fp->_flags & _IO_ERR_SEEN;
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fp->_flags &= ~_IO_ERR_SEEN;
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count = _IO_getline (fp, buf, MIN ((size_t) n - 1, size), '\n', 1);
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/* If we read in some bytes and errno is EAGAIN, that error will
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be reported for next read. */
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if (count == 0 || ((fp->_flags & _IO_ERR_SEEN) && errno != EAGAIN))
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result = NULL;
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else if (count >= size)
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__chk_fail ();
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else
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{
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buf[count] = '\0';
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result = buf;
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}
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fp->_flags |= old_error;
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_IO_release_lock (fp);
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return result;
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}
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