ef0a265086
* VFS and installed MFSes must be in sync before and after this change * Use struct stat from NetBSD. It requires adding new STAT, FSTAT and LSTAT syscalls. Libc modification is both backward and forward compatible. Also new struct stat uses modern field sizes to avoid ABI incompatibility, when we update uid_t, gid_t and company. Exceptions are ino_t and off_t in old libc (though paddings added).
136 lines
4 KiB
C
136 lines
4 KiB
C
/* $NetBSD: makebuf.c,v 1.15 2008/03/13 15:40:00 christos Exp $ */
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/*-
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* Copyright (c) 1990, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* Chris Torek.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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#if defined(LIBC_SCCS) && !defined(lint)
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#if 0
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static char sccsid[] = "@(#)makebuf.c 8.1 (Berkeley) 6/4/93";
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#else
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__RCSID("$NetBSD: makebuf.c,v 1.15 2008/03/13 15:40:00 christos Exp $");
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#endif
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#endif /* LIBC_SCCS and not lint */
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#include "namespace.h"
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <assert.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include "reentrant.h"
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#include "local.h"
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/*
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* Allocate a file buffer, or switch to unbuffered I/O.
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* Per the ANSI C standard, ALL tty devices default to line buffered.
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*
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* As a side effect, we set __SOPT or __SNPT (en/dis-able fseek
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* optimisation) right after the fstat() that finds the buffer size.
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*/
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void
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__smakebuf(fp)
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FILE *fp;
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{
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void *p;
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int flags;
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size_t size;
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int couldbetty;
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_DIAGASSERT(fp != NULL);
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if (fp->_flags & __SNBF) {
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fp->_bf._base = fp->_p = fp->_nbuf;
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fp->_bf._size = 1;
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return;
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}
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flags = __swhatbuf(fp, &size, &couldbetty);
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if ((p = malloc(size)) == NULL) {
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fp->_flags |= __SNBF;
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fp->_bf._base = fp->_p = fp->_nbuf;
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fp->_bf._size = 1;
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return;
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}
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__cleanup = _cleanup;
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flags |= __SMBF;
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fp->_bf._base = fp->_p = p;
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fp->_bf._size = size;
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if (couldbetty && isatty(__sfileno(fp)))
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flags |= __SLBF;
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fp->_flags |= flags;
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}
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/*
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* Internal routine to determine `proper' buffering for a file.
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*/
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int
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__swhatbuf(fp, bufsize, couldbetty)
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FILE *fp;
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size_t *bufsize;
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int *couldbetty;
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{
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struct stat st;
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_DIAGASSERT(fp != NULL);
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_DIAGASSERT(bufsize != NULL);
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_DIAGASSERT(couldbetty != NULL);
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if (__sfileno(fp) == -1 || fstat(__sfileno(fp), &st) < 0) {
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*couldbetty = 0;
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*bufsize = BUFSIZ;
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return (__SNPT);
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}
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/* could be a tty iff it is a character device */
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*couldbetty = S_ISCHR(st.st_mode);
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/*
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* Optimise fseek() only if it is a regular file. (The test for
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* __sseek is mainly paranoia.) It is safe to set _blksize
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* unconditionally; it will only be used if __SOPT is also set.
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*/
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#ifdef __minix
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if (st.st_blksize == 0) {
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/* 0 in 2 cases: upgrade from old to new struct stat or
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* there is a bug in underlying fs.
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*/
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*bufsize = fp->_blksize = MINIX_ST_BLKSIZE;
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} else
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#endif
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*bufsize = fp->_blksize = st.st_blksize;
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return ((st.st_mode & S_IFMT) == S_IFREG && fp->_seek == __sseek ?
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__SOPT : __SNPT);
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}
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