xref: /illumos-gate/usr/src/lib/libc/port/stdio/setvbuf.c (revision 8b80e8cb6855118d46f605e91b5ed4ce83417395)
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 #pragma ident	"%Z%%M%	%I%	%E% SMI"
31 
32 #include "lint.h"
33 #include "file64.h"
34 #include "mtlib.h"
35 #include <sys/types.h>
36 #include <stdio.h>
37 #include <stdlib.h>
38 #include <thread.h>
39 #include <synch.h>
40 #include "stdiom.h"
41 
42 int
43 setvbuf(FILE *iop, char *abuf, int type, size_t size)
44 {
45 
46 	Uchar	*buf = (Uchar *)abuf;
47 	Uchar *temp;
48 	int	sflag = iop->_flag & _IOMYBUF;
49 	rmutex_t *lk;
50 	int fd = GET_FD(iop);
51 
52 	FLOCKFILE(lk, iop);
53 	iop->_flag &= ~(_IOMYBUF | _IONBF | _IOLBF);
54 	switch (type) {
55 	/* note that the flags are the same as the possible values for type */
56 	case _IONBF:
57 		iop->_flag |= _IONBF;	 /* file is unbuffered */
58 #ifndef _STDIO_ALLOCATE
59 		if (fd < 2) {
60 			/* use special buffer for std{in,out} */
61 			buf = (fd == 0) ? _sibuf : _sobuf;
62 			size = BUFSIZ;
63 		} else /* needed for ifdef */
64 #endif
65 		if (fd < _NFILE) {
66 			buf = _smbuf[fd];
67 			size = _SMBFSZ - PUSHBACK;
68 		} else
69 			if ((buf = malloc(_SMBFSZ * sizeof (Uchar))) != NULL) {
70 				iop->_flag |= _IOMYBUF;
71 				size = _SMBFSZ - PUSHBACK;
72 			} else {
73 				FUNLOCKFILE(lk);
74 				return (EOF);
75 			}
76 		break;
77 	case _IOLBF:
78 	case _IOFBF:
79 		iop->_flag |= type;	/* buffer file */
80 		/*
81 		 * need at least an 8 character buffer for
82 		 * out_of_sync concerns.
83 		 */
84 		if (size <= _SMBFSZ) {
85 			size = BUFSIZ;
86 			buf = NULL;
87 		}
88 		if (buf == NULL) {
89 			if ((buf = malloc(sizeof (Uchar) *
90 			    (size + _SMBFSZ))) != NULL)
91 				iop->_flag |= _IOMYBUF;
92 			else {
93 				FUNLOCKFILE(lk);
94 				return (EOF);
95 			}
96 		}
97 		else
98 			size -= _SMBFSZ;
99 		break;
100 	default:
101 		FUNLOCKFILE(lk);
102 		return (EOF);
103 	}
104 	if (iop->_base != NULL && sflag)
105 		free((char *)iop->_base - PUSHBACK);
106 	temp = buf + PUSHBACK;
107 	iop->_base = temp;
108 	_setbufend(iop, temp + size);
109 	iop->_ptr = temp;
110 	iop->_cnt = 0;
111 	FUNLOCKFILE(lk);
112 	return (0);
113 }
114