minix/lib/libc/stdio/fdopen.c

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/* $NetBSD: fdopen.c,v 1.16 2012/03/15 18:22:30 christos Exp $ */
/*-
* 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. 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.
*/
#include <sys/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
#if 0
static char sccsid[] = "@(#)fdopen.c 8.1 (Berkeley) 6/4/93";
#else
__RCSID("$NetBSD: fdopen.c,v 1.16 2012/03/15 18:22:30 christos Exp $");
#endif
#endif /* LIBC_SCCS and not lint */
#include "namespace.h"
#include <sys/types.h>
#include <assert.h>
#include <errno.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdio.h>
#include <limits.h>
#include "reentrant.h"
#include "local.h"
#ifdef __weak_alias
__weak_alias(fdopen,_fdopen)
#endif
FILE *
fdopen(int fd, const char *mode)
{
FILE *fp;
int flags, oflags, fdflags, tmp;
_DIAGASSERT(fd != -1);
/*
* File descriptors are a full int, but _file is only a short.
* If we get a valid file descriptor that is greater or equal to
* USHRT_MAX, then the fd will get sign-extended into an
* invalid file descriptor. Handle this case by failing the
* open. (We treat the short as unsigned, and special-case -1).
*/
if (fd >= USHRT_MAX) {
errno = EMFILE;
return NULL;
}
if ((flags = __sflags(mode, &oflags)) == 0)
return NULL;
/* Make sure the mode the user wants is a subset of the actual mode. */
if ((fdflags = fcntl(fd, F_GETFL, 0)) < 0)
return NULL;
tmp = fdflags & O_ACCMODE;
if (tmp != O_RDWR && (tmp != (oflags & O_ACCMODE))) {
errno = EINVAL;
return NULL;
}
if (oflags & O_NONBLOCK) {
struct stat st;
if (fstat(fd, &st) == -1) {
return NULL;
}
if (!S_ISREG(st.st_mode)) {
errno = EFTYPE;
return NULL;
}
}
if ((fp = __sfp()) == NULL)
return NULL;
fp->_flags = flags;
/*
* If opened for appending, but underlying descriptor does not have
* O_APPEND bit set, assert __SAPP so that __swrite() will lseek to
* end before each write.
*/
if ((oflags & O_APPEND) && !(fdflags & O_APPEND))
fp->_flags |= __SAPP;
fp->_file = fd;
fp->_cookie = fp;
fp->_read = __sread;
fp->_write = __swrite;
fp->_seek = __sseek;
fp->_close = __sclose;
return fp;
}