diff options
Diffstat (limited to 'lib/libc/stdio/refill.c')
| -rw-r--r-- | lib/libc/stdio/refill.c | 150 |
1 files changed, 150 insertions, 0 deletions
diff --git a/lib/libc/stdio/refill.c b/lib/libc/stdio/refill.c new file mode 100644 index 000000000000..b3e292a4b7e1 --- /dev/null +++ b/lib/libc/stdio/refill.c @@ -0,0 +1,150 @@ +/*- + * Copyright (c) 1990, 1993 + * The Regents of the University of California. All rights reserved. + * + * This code is derived from software contributed to Berkeley by + * Chris Torek. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. All advertising materials mentioning features or use of this software + * must display the following acknowledgement: + * This product includes software developed by the University of + * California, Berkeley and its contributors. + * 4. Neither the name of the University nor the names of its contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +#if defined(LIBC_SCCS) && !defined(lint) +#if 0 +static char sccsid[] = "@(#)refill.c 8.1 (Berkeley) 6/4/93"; +#endif +static const char rcsid[] = + "$FreeBSD$"; +#endif /* LIBC_SCCS and not lint */ + +#include "namespace.h" +#include <errno.h> +#include <stdio.h> +#include <stdlib.h> +#include "un-namespace.h" + +#include "libc_private.h" +#include "local.h" + +static int lflush __P((FILE *)); + +static int +lflush(FILE *fp) +{ + int ret = 0; + + if ((fp->_flags & (__SLBF|__SWR)) == (__SLBF|__SWR)) { + FLOCKFILE(fp); + ret = __sflush(fp); + FUNLOCKFILE(fp); + } + return (ret); +} + +/* + * Refill a stdio buffer. + * Return EOF on eof or error, 0 otherwise. + */ +int +__srefill(FILE *fp) +{ + + /* make sure stdio is set up */ + if (!__sdidinit) + __sinit(); + + fp->_r = 0; /* largely a convenience for callers */ + + /* SysV does not make this test; take it out for compatibility */ + if (fp->_flags & __SEOF) + return (EOF); + + /* if not already reading, have to be reading and writing */ + if ((fp->_flags & __SRD) == 0) { + if ((fp->_flags & __SRW) == 0) { + errno = EBADF; + fp->_flags |= __SERR; + return (EOF); + } + /* switch to reading */ + if (fp->_flags & __SWR) { + if (__sflush(fp)) + return (EOF); + fp->_flags &= ~__SWR; + fp->_w = 0; + fp->_lbfsize = 0; + } + fp->_flags |= __SRD; + } else { + /* + * We were reading. If there is an ungetc buffer, + * we must have been reading from that. Drop it, + * restoring the previous buffer (if any). If there + * is anything in that buffer, return. + */ + if (HASUB(fp)) { + FREEUB(fp); + if ((fp->_r = fp->_ur) != 0) { + fp->_p = fp->_extra->_up; + return (0); + } + } + } + + if (fp->_bf._base == NULL) + __smakebuf(fp); + + /* + * Before reading from a line buffered or unbuffered file, + * flush all line buffered output files, per the ANSI C + * standard. + */ + if (fp->_flags & (__SLBF|__SNBF)) { + /* Ignore this file in _fwalk to avoid potential deadlock. */ + fp->_flags |= __SIGN; + (void) _fwalk(lflush); + fp->_flags &= ~__SIGN; + + /* Now flush this file without locking it. */ + if ((fp->_flags & (__SLBF|__SWR)) == (__SLBF|__SWR)) + __sflush(fp); + } + fp->_p = fp->_bf._base; + fp->_r = _sread(fp, (char *)fp->_p, fp->_bf._size); + fp->_flags &= ~__SMOD; /* buffer contents are again pristine */ + if (fp->_r <= 0) { + if (fp->_r == 0) + fp->_flags |= __SEOF; + else { + fp->_r = 0; + fp->_flags |= __SERR; + } + return (EOF); + } + return (0); +} |