xref: /illumos-gate/usr/src/cmd/ttymon/tmautobaud.c (revision f2ae17ede4a9a93585872a9aa83120497285bdd0)
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, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 /*
23  * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 /*	Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T	*/
28 /*	  All Rights Reserved	*/
29 
30 #include <stdio.h>
31 #include <errno.h>
32 #include <fcntl.h>
33 #include <string.h>
34 #include <termio.h>
35 #include <unistd.h>
36 #include <signal.h>
37 #include <stdlib.h>
38 #include <sys/types.h>
39 #include <sys/stropts.h>
40 
41 #include "tmextern.h"
42 
43 #define	NTRY	5
44 
45 /*
46  * At this time, we only recognize certain speeds.
47  * This table can be expanded if new patterns are found
48  */
49 static struct	autobaud {
50 	char	*a_speed;
51 	char	*a_pattern;	/* first byte is length */
52 } autob2400[] = {
53 #ifdef i386
54 	/*
55 	 * These are the bit patterns returned on x86 boxes
56 	 */
57 	"110",		"\1\000",
58 #else
59 	"110",		"\3\000\000\000",
60 #endif
61 	"1200",		"\2\346\200",
62 	"2400",		"\1\15",
63 	"4800",		"\1\371",
64 	"4800",		"\1\362",
65 	"9600",		"\1\377",
66 	0,		0
67 };
68 
69 /*
70  *	auto_termio - set termio to allow autobaud
71  *		    - the line is set to raw mode, with VMIN = 5, VTIME = 1
72  *		    - baud rate is set to 2400
73  */
74 int
75 auto_termio(int fd)
76 {
77 	struct termio termio;
78 	struct termios termios;
79 
80 	if (ioctl(fd, TCGETS, &termios) == -1) {
81 		if (ioctl(fd, TCGETA, &termio) == -1) {
82 			log("auto_termio: ioctl TCGETA failed, fd = %d: %s", fd,
83 			    strerror(errno));
84 			return (-1);
85 		}
86 		termio.c_iflag = 0;
87 		termio.c_cflag &= ~(CBAUD|CSIZE|PARENB);
88 		termio.c_cflag |= CREAD|HUPCL|(CS8&CSIZE)|(B2400&CBAUD);
89 		termio.c_lflag &= ~(ISIG|ICANON|ECHO|ECHOE|ECHOK);
90 		termio.c_oflag = 0;
91 
92 		termio.c_cc[VMIN] = 5;
93 		termio.c_cc[VTIME] = 1;
94 
95 		if (ioctl(fd, TCSETAF, &termio) == -1) {
96 			log("auto_termio: ioctl TCSETAF failed, fd = %d: %s",
97 			    fd, strerror(errno));
98 			return (-1);
99 		}
100 	} else {
101 		termios.c_iflag &= 0xffff0000;
102 		termios.c_cflag &= ~(CSIZE|PARENB);
103 		termios.c_cflag |= CREAD|HUPCL|(CS8&CSIZE);
104 		termios.c_lflag &= ~(ISIG|ICANON|ECHO|ECHOE|ECHOK);
105 		termios.c_oflag &= 0xffff0000;
106 
107 		termios.c_cc[VMIN] = 5;
108 		termios.c_cc[VTIME] = 1;
109 		(void) cfsetospeed(&termios, B2400);
110 
111 		if (ioctl(fd, TCSETSF, &termios) == -1) {
112 			log("auto_termio: ioctl TCSETSF failed, fd = %d: %s",
113 			    fd, strerror(errno));
114 			return (-1);
115 		}
116 	}
117 	return (0);
118 }
119 
120 /*
121  *	autobaud - determine the baudrate by reading data at 2400 baud rate
122  *		 - the program is anticipating <CR>
123  *		 - the bit pattern is matched again an autobaud table
124  *		 - if a match is found, the matched speed is returned
125  *		 - otherwise, NULL is returned
126  */
127 
128 char *
129 autobaud(int fd, int timeout)
130 {
131 	int i, k, count;
132 	static char	buf[5];
133 	char *cp = buf;
134 	struct	autobaud *tp;
135 	struct	sigaction sigact;
136 
137 #ifdef	DEBUG
138 	debug("in autobaud");
139 #endif
140 	(void) auto_termio(fd);
141 	sigact.sa_flags = 0;
142 	sigact.sa_handler = SIG_IGN;
143 	(void) sigemptyset(&sigact.sa_mask);
144 	(void) sigaction(SIGINT, &sigact, NULL);
145 	count = NTRY;
146 	while (count--) {
147 		if (timeout) {
148 			sigact.sa_flags = 0;
149 			sigact.sa_handler = timedout;
150 			(void) sigemptyset(&sigact.sa_mask);
151 			(void) sigaction(SIGALRM, &sigact, NULL);
152 			(void) alarm((unsigned)timeout);
153 		}
154 		cp = &buf[1];
155 		if (peek_ptr != NULL) {
156 			k = peek_ptr->len;
157 			(void) strncpy(cp, peek_ptr->buf, k);
158 			peek_ptr = NULL;
159 		} else if ((k = read(fd, cp, 5)) < 0) {
160 			fatal("autobaud: read failed: %s", strerror(errno));
161 		}
162 		if (timeout)
163 			(void) alarm((unsigned)0);
164 		buf[0] = (char)k;
165 		for (tp = autob2400; tp->a_speed; tp++) {
166 			for (i = 0; ; i++) {
167 				if (buf[i] != tp->a_pattern[i])
168 					break;
169 				if (i == buf[0]) {
170 					return (tp->a_speed);
171 				}
172 			}
173 		}
174 		flush_input(fd);
175 	} /* end while */
176 	return (NULL);		/* autobaud failed */
177 }
178