xref: /csrg-svn/lib/libc/stdio/fdopen.c (revision 46209)
146069Sbostic /*-
246069Sbostic  * Copyright (c) 1990 The Regents of the University of California.
346069Sbostic  * All rights reserved.
446069Sbostic  *
546069Sbostic  * This code is derived from software contributed to Berkeley by
646069Sbostic  * Chris Torek.
746069Sbostic  *
846069Sbostic  * %sccs.include.redist.c%
921400Sdist  */
1021400Sdist 
1126642Sdonn #if defined(LIBC_SCCS) && !defined(lint)
12*46209Sbostic static char sccsid[] = "@(#)fdopen.c	5.4 (Berkeley) 02/01/91";
1346069Sbostic #endif /* LIBC_SCCS and not lint */
1421400Sdist 
1517952Sserge #include <sys/types.h>
1617952Sserge #include <sys/file.h>
1717952Sserge #include <stdio.h>
18*46209Sbostic #include <errno.h>
1946069Sbostic #include "local.h"
201999Swnj 
211999Swnj FILE *
221999Swnj fdopen(fd, mode)
2346069Sbostic 	int fd;
2446069Sbostic 	char *mode;
251999Swnj {
26*46209Sbostic 	register FILE *fp;
2746069Sbostic 	static int nofile;
28*46209Sbostic 	int flags, oflags, fdflags, tmp;
291999Swnj 
3046069Sbostic 	if (nofile == 0)
3117952Sserge 		nofile = getdtablesize();
3217952Sserge 
33*46209Sbostic 	if ((flags = __sflags(mode, &oflags)) == 0)
3413495Ssam 		return (NULL);
3517952Sserge 
3646069Sbostic 	/* Make sure the mode the user wants is a subset of the actual mode. */
37*46209Sbostic 	if ((fdflags = fcntl(fd, F_GETFL, 0)) < 0)
38*46209Sbostic 		return (NULL);
39*46209Sbostic 	tmp = fdflags & O_ACCMODE;
40*46209Sbostic 	if (tmp != O_RDWR && (tmp != (oflags & O_ACCMODE))) {
4146069Sbostic 		errno = EINVAL;
4217952Sserge 		return (NULL);
4346069Sbostic 	}
4417952Sserge 
4546069Sbostic 	if ((fp = __sfp()) == NULL)
4646069Sbostic 		return (NULL);
47*46209Sbostic 	fp->_flags = flags;
4846069Sbostic 	/*
4946069Sbostic 	 * If opened for appending, but underlying descriptor does not have
5046069Sbostic 	 * O_APPEND bit set, assert __SAPP so that __swrite() will lseek to
5146069Sbostic 	 * end before each write.
5246069Sbostic 	 */
5346069Sbostic 	if ((oflags & O_APPEND) && !(fdflags & O_APPEND))
5446069Sbostic 		fp->_flags |= __SAPP;
5546069Sbostic 	fp->_file = fd;
5646069Sbostic 	fp->_cookie = fp;
5746069Sbostic 	fp->_read = __sread;
5846069Sbostic 	fp->_write = __swrite;
5946069Sbostic 	fp->_seek = __sseek;
6046069Sbostic 	fp->_close = __sclose;
6146069Sbostic 	return (fp);
621999Swnj }
63