xref: /minix3/lib/libc/stdio/fdopen.c (revision f14fb602092e015ff630df58e17c2a9cd57d29b3)
1*f14fb602SLionel Sambuc /*	$NetBSD: fdopen.c,v 1.16 2012/03/15 18:22:30 christos Exp $	*/
22fe8fb19SBen Gras 
32fe8fb19SBen Gras /*-
42fe8fb19SBen Gras  * Copyright (c) 1990, 1993
52fe8fb19SBen Gras  *	The Regents of the University of California.  All rights reserved.
62fe8fb19SBen Gras  *
72fe8fb19SBen Gras  * This code is derived from software contributed to Berkeley by
82fe8fb19SBen Gras  * Chris Torek.
92fe8fb19SBen Gras  *
102fe8fb19SBen Gras  * Redistribution and use in source and binary forms, with or without
112fe8fb19SBen Gras  * modification, are permitted provided that the following conditions
122fe8fb19SBen Gras  * are met:
132fe8fb19SBen Gras  * 1. Redistributions of source code must retain the above copyright
142fe8fb19SBen Gras  *    notice, this list of conditions and the following disclaimer.
152fe8fb19SBen Gras  * 2. Redistributions in binary form must reproduce the above copyright
162fe8fb19SBen Gras  *    notice, this list of conditions and the following disclaimer in the
172fe8fb19SBen Gras  *    documentation and/or other materials provided with the distribution.
182fe8fb19SBen Gras  * 3. Neither the name of the University nor the names of its contributors
192fe8fb19SBen Gras  *    may be used to endorse or promote products derived from this software
202fe8fb19SBen Gras  *    without specific prior written permission.
212fe8fb19SBen Gras  *
222fe8fb19SBen Gras  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
232fe8fb19SBen Gras  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
242fe8fb19SBen Gras  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
252fe8fb19SBen Gras  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
262fe8fb19SBen Gras  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
272fe8fb19SBen Gras  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
282fe8fb19SBen Gras  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
292fe8fb19SBen Gras  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
302fe8fb19SBen Gras  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
312fe8fb19SBen Gras  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
322fe8fb19SBen Gras  * SUCH DAMAGE.
332fe8fb19SBen Gras  */
342fe8fb19SBen Gras 
352fe8fb19SBen Gras #include <sys/cdefs.h>
362fe8fb19SBen Gras #if defined(LIBC_SCCS) && !defined(lint)
372fe8fb19SBen Gras #if 0
382fe8fb19SBen Gras static char sccsid[] = "@(#)fdopen.c	8.1 (Berkeley) 6/4/93";
392fe8fb19SBen Gras #else
40*f14fb602SLionel Sambuc __RCSID("$NetBSD: fdopen.c,v 1.16 2012/03/15 18:22:30 christos Exp $");
412fe8fb19SBen Gras #endif
422fe8fb19SBen Gras #endif /* LIBC_SCCS and not lint */
432fe8fb19SBen Gras 
442fe8fb19SBen Gras #include "namespace.h"
452fe8fb19SBen Gras #include <sys/types.h>
462fe8fb19SBen Gras 
472fe8fb19SBen Gras #include <assert.h>
482fe8fb19SBen Gras #include <errno.h>
492fe8fb19SBen Gras #include <fcntl.h>
502fe8fb19SBen Gras #include <unistd.h>
512fe8fb19SBen Gras #include <stdio.h>
522fe8fb19SBen Gras #include <limits.h>
532fe8fb19SBen Gras 
542fe8fb19SBen Gras #include "reentrant.h"
552fe8fb19SBen Gras #include "local.h"
562fe8fb19SBen Gras 
572fe8fb19SBen Gras #ifdef __weak_alias
__weak_alias(fdopen,_fdopen)582fe8fb19SBen Gras __weak_alias(fdopen,_fdopen)
592fe8fb19SBen Gras #endif
602fe8fb19SBen Gras 
612fe8fb19SBen Gras FILE *
62*f14fb602SLionel Sambuc fdopen(int fd, const char *mode)
632fe8fb19SBen Gras {
642fe8fb19SBen Gras 	FILE *fp;
652fe8fb19SBen Gras 	int flags, oflags, fdflags, tmp;
662fe8fb19SBen Gras 
672fe8fb19SBen Gras 	_DIAGASSERT(fd != -1);
682fe8fb19SBen Gras 
692fe8fb19SBen Gras 	/*
702fe8fb19SBen Gras 	 * File descriptors are a full int, but _file is only a short.
712fe8fb19SBen Gras 	 * If we get a valid file descriptor that is greater or equal to
722fe8fb19SBen Gras 	 * USHRT_MAX, then the fd will get sign-extended into an
732fe8fb19SBen Gras 	 * invalid file descriptor.  Handle this case by failing the
742fe8fb19SBen Gras 	 * open. (We treat the short as unsigned, and special-case -1).
752fe8fb19SBen Gras 	 */
762fe8fb19SBen Gras 	if (fd >= USHRT_MAX) {
772fe8fb19SBen Gras 		errno = EMFILE;
782fe8fb19SBen Gras 		return NULL;
792fe8fb19SBen Gras 	}
802fe8fb19SBen Gras 
812fe8fb19SBen Gras 	if ((flags = __sflags(mode, &oflags)) == 0)
82*f14fb602SLionel Sambuc 		return NULL;
832fe8fb19SBen Gras 
842fe8fb19SBen Gras 	/* Make sure the mode the user wants is a subset of the actual mode. */
852fe8fb19SBen Gras 	if ((fdflags = fcntl(fd, F_GETFL, 0)) < 0)
86*f14fb602SLionel Sambuc 		return NULL;
872fe8fb19SBen Gras 	tmp = fdflags & O_ACCMODE;
882fe8fb19SBen Gras 	if (tmp != O_RDWR && (tmp != (oflags & O_ACCMODE))) {
892fe8fb19SBen Gras 		errno = EINVAL;
90*f14fb602SLionel Sambuc 		return NULL;
912fe8fb19SBen Gras 	}
922fe8fb19SBen Gras 
932fe8fb19SBen Gras 	if (oflags & O_NONBLOCK) {
942fe8fb19SBen Gras 		struct stat st;
952fe8fb19SBen Gras 		if (fstat(fd, &st) == -1) {
96*f14fb602SLionel Sambuc 			return NULL;
972fe8fb19SBen Gras 		}
982fe8fb19SBen Gras 		if (!S_ISREG(st.st_mode)) {
992fe8fb19SBen Gras 			errno = EFTYPE;
100*f14fb602SLionel Sambuc 			return NULL;
1012fe8fb19SBen Gras 		}
1022fe8fb19SBen Gras 	}
1032fe8fb19SBen Gras 
1042fe8fb19SBen Gras 	if ((fp = __sfp()) == NULL)
105*f14fb602SLionel Sambuc 		return NULL;
1062fe8fb19SBen Gras 	fp->_flags = flags;
1072fe8fb19SBen Gras 	/*
1082fe8fb19SBen Gras 	 * If opened for appending, but underlying descriptor does not have
1092fe8fb19SBen Gras 	 * O_APPEND bit set, assert __SAPP so that __swrite() will lseek to
1102fe8fb19SBen Gras 	 * end before each write.
1112fe8fb19SBen Gras 	 */
1122fe8fb19SBen Gras 	if ((oflags & O_APPEND) && !(fdflags & O_APPEND))
1132fe8fb19SBen Gras 		fp->_flags |= __SAPP;
1142fe8fb19SBen Gras 	fp->_file = fd;
1152fe8fb19SBen Gras 	fp->_cookie = fp;
1162fe8fb19SBen Gras 	fp->_read = __sread;
1172fe8fb19SBen Gras 	fp->_write = __swrite;
1182fe8fb19SBen Gras 	fp->_seek = __sseek;
1192fe8fb19SBen Gras 	fp->_close = __sclose;
120*f14fb602SLionel Sambuc 	return fp;
1212fe8fb19SBen Gras }
122