xref: /openbsd/lib/libc/termios/tcflow.c (revision 404b540a)
1 /*	$OpenBSD: tcflow.c,v 1.5 2005/08/05 13:03:00 espie Exp $ */
2 /*-
3  * Copyright (c) 1989, 1993
4  *	The Regents of the University of California.  All rights reserved.
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  * 3. Neither the name of the University nor the names of its contributors
15  *    may be used to endorse or promote products derived from this software
16  *    without specific prior written permission.
17  *
18  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
19  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
22  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28  * SUCH DAMAGE.
29  */
30 
31 #include <sys/ioctl.h>
32 #include <termios.h>
33 #include <unistd.h>
34 #include <errno.h>
35 
36 int
37 tcflow(int fd, int action)
38 {
39 	struct termios term;
40 	u_char c;
41 
42 	switch (action) {
43 	case TCOOFF:
44 		return (ioctl(fd, TIOCSTOP, 0));
45 	case TCOON:
46 		return (ioctl(fd, TIOCSTART, 0));
47 	case TCION:
48 	case TCIOFF:
49 		if (tcgetattr(fd, &term) == -1)
50 			return (-1);
51 		c = term.c_cc[action == TCIOFF ? VSTOP : VSTART];
52 		if (c != _POSIX_VDISABLE && write(fd, &c, sizeof(c)) == -1)
53 			return (-1);
54 		return (0);
55 	default:
56 		errno = EINVAL;
57 		return (-1);
58 	}
59 	/* NOTREACHED */
60 }
61