xref: /illumos-gate/usr/src/lib/libc/port/stdio/setvbuf.c (revision 16d40492a57db8c0430b8ea78cfc89a12aa29c36)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 /*	Copyright (c) 1988 AT&T	*/
28 /*	  All Rights Reserved	*/
29 
30 #include "lint.h"
31 #include "file64.h"
32 #include "mtlib.h"
33 #include <sys/types.h>
34 #include <stdio.h>
35 #include <stdlib.h>
36 #include <thread.h>
37 #include <synch.h>
38 #include "stdiom.h"
39 
40 int
41 setvbuf(FILE *iop, char *abuf, int type, size_t size)
42 {
43 
44 	Uchar	*buf = (Uchar *)abuf;
45 	Uchar *temp;
46 	int	sflag = iop->_flag & _IOMYBUF;
47 	rmutex_t *lk;
48 	int fd = _get_fd(iop);
49 
50 	FLOCKFILE(lk, iop);
51 	iop->_flag &= ~(_IOMYBUF | _IONBF | _IOLBF);
52 	switch (type) {
53 	/* note that the flags are the same as the possible values for type */
54 	case _IONBF:
55 		iop->_flag |= _IONBF;	 /* file is unbuffered */
56 		if (fd == 0 || fd == 1) {
57 			/* use special buffer for std{in,out} */
58 			buf = (fd == 0) ? _sibuf : _sobuf;
59 			size = BUFSIZ;
60 		} else if (fd >= 2 && fd < _NFILE) {
61 			buf = _smbuf[fd];
62 			size = _SMBFSZ - PUSHBACK;
63 		} else {
64 			if ((buf = malloc(_SMBFSZ * sizeof (Uchar))) != NULL) {
65 				iop->_flag |= _IOMYBUF;
66 				size = _SMBFSZ - PUSHBACK;
67 			} else {
68 				FUNLOCKFILE(lk);
69 				return (EOF);
70 			}
71 		}
72 		break;
73 	case _IOLBF:
74 	case _IOFBF:
75 		iop->_flag |= type;	/* buffer file */
76 		/*
77 		 * need at least an 8 character buffer for
78 		 * out_of_sync concerns.
79 		 */
80 		if (size <= _SMBFSZ) {
81 			size = BUFSIZ;
82 			buf = NULL;
83 		}
84 		if (buf == NULL) {
85 			if ((buf = malloc(sizeof (Uchar) *
86 			    (size + _SMBFSZ))) != NULL)
87 				iop->_flag |= _IOMYBUF;
88 			else {
89 				FUNLOCKFILE(lk);
90 				return (EOF);
91 			}
92 		}
93 		else
94 			size -= _SMBFSZ;
95 		break;
96 	default:
97 		FUNLOCKFILE(lk);
98 		return (EOF);
99 	}
100 	if (iop->_base != NULL && sflag)
101 		free((char *)iop->_base - PUSHBACK);
102 	temp = buf + PUSHBACK;
103 	iop->_base = temp;
104 	_setbufend(iop, temp + size);
105 	iop->_ptr = temp;
106 	iop->_cnt = 0;
107 	FUNLOCKFILE(lk);
108 	return (0);
109 }
110