xref: /illumos-gate/usr/src/cmd/ttymon/tmsac.c (revision cb1bb6c32d034ea24e8549ef763c9c2b79413eb8)
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  /*	Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T	*/
27  /*	  All Rights Reserved	*/
28  
29  #include <stdlib.h>
30  #include <stdio.h>
31  #include <errno.h>
32  #include <fcntl.h>
33  #include <signal.h>
34  #include <string.h>
35  #include <unistd.h>
36  #include "ttymon.h"
37  #include "tmextern.h"
38  #include "sac.h"
39  
40  /*
41   *	openpid	- open the pid and put ttymon's pid in it
42   *		- put an advisory lock on the file
43   *		- to prevent another instance of ttymon in same directory
44   *		- SAC also makes use of the lock
45   *		- fd 0 is reserved for pid file
46   */
47  void
48  openpid(void)
49  {
50  	char lockbuf[16];	/* large enough for a PID string */
51  
52  	(void) close(0);
53  	/* open for read first, otherwise, may delete the pid already there */
54  	if ((Lckfd = open(PIDFILE, O_RDONLY)) != -1) {
55  		if (lockf(Lckfd, F_TEST, 0L) == -1)
56  			fatal("pid file is locked. ttymon may already be "
57  			    "running!");
58  		(void) close(Lckfd);
59  	}
60  
61  	if ((Lckfd = open(PIDFILE, O_WRONLY|O_CREAT|O_TRUNC, 0644)) != 0)
62  		fatal("open pid file failed: %s", strerror(errno));
63  
64  	if (lockf(Lckfd, F_LOCK, 0L) == -1)
65  		fatal("lock pid file failed: %s", strerror(errno));
66  
67  	(void) snprintf(lockbuf, sizeof (lockbuf), "%ld", getpid());
68  	(void) write(Lckfd, lockbuf, strlen(lockbuf) + 1);
69  #ifdef	DEBUG
70  	log("fd(pid)\t = %d", Lckfd);
71  #endif
72  }
73  
74  /*
75   * openpipes() -- open pmpipe and sacpipe to communicate with SAC
76   *	       -- Pfd, Sfd are global file descriptors for pmpipe, sacpipe
77   */
78  
79  void
80  openpipes(void)
81  {
82  	Sfd = open(SACPIPE, O_WRONLY);
83  	if (Sfd < 0)
84  		fatal("open sacpipe failed: %s", strerror(errno));
85  
86  	Pfd = open(PMPIPE, O_RDWR|O_NONBLOCK);
87  	if (Pfd < 0)
88  		fatal("open pmpipe failed: %s", strerror(errno));
89  
90  #ifdef	DEBUG
91  	log("fd(sacpipe)\t = %d", Sfd);
92  	log("fd(pmpipe)\t = %d", Pfd);
93  #endif
94  }
95  
96  /*
97   * remove_env(env) - remove an environment variable from the environment
98   */
99  static	void
100  remove_env(char *env)
101  {
102  	char	**p;
103  	char	**rp = NULL;
104  
105  	p = environ;
106  	if (p == NULL)
107  		return;
108  	while (*p) {
109  		if (strncmp(*p, env, strlen(env)) == 0)
110  			rp = p;
111  		p++;
112  	}
113  	if (rp) {
114  		*rp = *--p;
115  		*p = NULL;
116  	}
117  }
118  
119  /*
120   * get_environ() -- get env variables PMTAG, ISTATE
121   *		 -- set global variables Tag, State
122   */
123  
124  void
125  get_environ(void)
126  {
127  	if ((Tag = getenv("PMTAG")) == NULL)
128  		fatal("PMTAG is missing");
129  
130  	if ((Istate = getenv("ISTATE")) == NULL)
131  		fatal("ISTATE is missing");
132  
133  	State = (strcmp(Istate, "enabled") == 0) ? PM_ENABLED : PM_DISABLED;
134  
135  	/*
136  	 * remove the environment variables so they will not
137  	 * be passed to the children
138  	 */
139  	remove_env("ISTATE");
140  	remove_env("PMTAG");
141  }
142  
143  /*
144   * sacpoll	- the event handler when sac event is posted
145   */
146  void
147  sacpoll(void)
148  {
149  	int	ret;
150  	char	oldState;
151  	struct	sacmsg sacmsg;
152  	struct	pmmsg pmmsg;
153  	sigset_t	cset;
154  	sigset_t	tset;
155  
156  #ifdef	DEBUG
157  	debug("in sacpoll");
158  #endif
159  
160  	/* we don't want to be interrupted by sigchild now */
161  	(void) sigprocmask(SIG_SETMASK, NULL, &cset);
162  	tset = cset;
163  	(void) sigaddset(&tset, SIGCLD);
164  	(void) sigprocmask(SIG_SETMASK, &tset, NULL);
165  
166  	/*
167  	 *	read sac messages, one at a time until no message
168  	 *	is left on the pipe.
169  	 *	the pipe is open with O_NONBLOCK, read will return -1
170  	 *	and errno = EAGAIN if nothing is on the pipe
171  	 */
172  	for (;;) {
173  
174  		ret = read(Pfd, &sacmsg, sizeof (sacmsg));
175  		if (ret < 0) {
176  			switch (errno) {
177  			case EAGAIN:
178  				/* no more data on the pipe */
179  				(void) sigprocmask(SIG_SETMASK, &cset, NULL);
180  				return;
181  			case EINTR:
182  				break;
183  			default:
184  				fatal("pmpipe read failed: %s",
185  				    strerror(errno));
186  				break;  /*NOTREACHED*/
187  			}
188  		} else if (ret == 0) {
189  			/* no more data on the pipe */
190  			(void) sigprocmask(SIG_SETMASK, &cset, NULL);
191  			return;
192  		} else {
193  			pmmsg.pm_size = 0;
194  			(void) strcpy(pmmsg.pm_tag, Tag);
195  			pmmsg.pm_maxclass = TM_MAXCLASS;
196  			pmmsg.pm_type = PM_STATUS;
197  			switch (sacmsg.sc_type) {
198  			case SC_STATUS:
199  				break;
200  			case SC_ENABLE:
201  				log("Got SC_ENABLE message");
202  				oldState = State;
203  				State = PM_ENABLED;
204  				if (State != oldState) {
205  #ifdef	DEBUG
206  					debug("state changed to ENABLED");
207  #endif
208  					state_change();
209  				}
210  				break;
211  			case SC_DISABLE:
212  				log("Got SC_DISABLE message");
213  				oldState = State;
214  				State = PM_DISABLED;
215  				if (State != oldState) {
216  #ifdef	DEBUG
217  					debug("state changed to DISABLED");
218  #endif
219  					state_change();
220  				}
221  				break;
222  			case SC_READDB:
223  				log("Got SC_READDB message");
224  				Reread_flag = 1;
225  				break;
226  			default:
227  				log("Got unknown message %d", sacmsg.sc_type);
228  				pmmsg.pm_type = PM_UNKNOWN;
229  				break;
230  			} /* end switch */
231  			pmmsg.pm_state = State;
232  
233  			while (write(Sfd, &pmmsg, sizeof (pmmsg)) !=
234  			    sizeof (pmmsg)) {
235  				if (errno == EINTR)
236  					continue;
237  				log("sanity response to SAC failed: %s",
238  				    strerror(errno));
239  				break;
240  			}
241  		}
242  	} /* end for loop */
243  }
244