xref: /illumos-gate/usr/src/cmd/lp/cmd/lpsched/msgs.c (revision 0a44ef6d)
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 2006 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 
31 #pragma ident	"%Z%%M%	%I%	%E% SMI"
32 
33 # include	<stdarg.h>
34 # include	<limits.h>
35 # include	<sys/types.h>
36 # include	<poll.h>
37 # include	<stropts.h>
38 # include	<unistd.h>
39 #include <syslog.h>
40 
41 # include	"lpsched.h"
42 
43 #define TURN_OFF(X,F)	(void)Fcntl(X, F_SETFL, (Fcntl(X, F_GETFL, 0) & ~(F)))
44 
45 
46 static void	conn_shutdown();
47 
48 extern int		Filter_Status;
49 extern void		dispatch();
50 extern int		Waitrequest;
51 void			shutdown_messages();
52 static char		*Message;
53 static int		MaxClients		= 0,
54 			do_msg();
55 extern int		Reserve_Fds;
56 extern int		Shutdown;
57 
58 MESG			*Net_md;
59 
60 /*
61 ** take_message() - WAIT FOR INTERRUPT OR ONE MESSAGE FROM USER PROCESS
62 */
63 
take_message(void)64 void take_message(void)
65 {
66     int		bytes;
67     int		i;
68     MESG *	md;
69 
70     for (EVER) {	/* not really forever...returns are in the loop */
71 	if ((md = mlisten()) == NULL)
72 	    switch(errno) {
73 	      case EAGAIN:
74 	      case EINTR:
75 		return;
76 
77 	      case ENOMEM:
78 		mallocfail();
79 		/* NOTREACHED */
80 
81 	      default:
82 		fail ("Unexpected streams error in mlisten (%s).\n" , PERROR);
83 	    }
84 
85 	/*
86 	 * Check for a dropped connection to a child.
87 	 * Normally a child should tell us that it is dying
88 	 * (with S_SHUTDOWN or S_SEND_CHILD), but it may have
89 	 * died a fast death. We'll simulate the message we
90 	 * wanted to get so we can use the same code to clean up.
91 	 */
92 	if ((md->event & POLLHUP) && !(md->event & POLLIN) ||
93 	    (md->event & (POLLERR|POLLNVAL))) {
94 		switch (md->type) {
95 
96 		case MD_CHILD:
97 			/*
98 			 * If the message descriptor is found in the
99 			 * exec table, it must be an interface pgm,
100 			 * notification, etc. Otherwise, it must be
101 			 * a network child.
102 			 */
103 			for (i = 0; Exec_Table[i] != NULL; i++)
104 				if (Exec_Table[i]->md == md)
105 					break;
106 
107 			if (Exec_Table[i] != NULL) {
108 				(void) putmessage(Message, S_CHILD_DONE,
109 					Exec_Table[i]->key, 0, 0);
110 			} else {
111 				(void) putmessage(Message, S_SHUTDOWN, 1);
112 			}
113 			bytes = 1;
114 			break;
115 
116 		default:
117 			bytes = -1;
118 			break;
119 
120 		}
121 
122 	} else {
123 		if (md->readfd == -1) { /* something happened to the readfd */
124 			syslog(LOG_DEBUG, "take_message: readfd is -1");
125 			return;
126 		}
127 		bytes = mread(md, Message, MSGMAX);
128 	}
129 
130 	switch (bytes) {
131 	  case -1:
132 	    if (errno == EINTR)
133 		return;
134 	    else
135 		fail ("Unexpected streams error (%s).\n" , PERROR);
136 	    break;
137 
138 	  case 0:
139 	    break;
140 
141 	  default:
142 	    if (do_msg(md))
143 		return;
144 	    break;
145 	}
146     }
147 }
148 
149 /*
150 ** do_msg() - HANDLE AN INCOMING MESSAGE
151 */
152 
153 static int
do_msg(MESG * md)154 do_msg(MESG *md)
155 {
156     int			type = mtype(Message);
157 
158     if (type != S_GOODBYE) {
159 	    md->wait = 0;
160 	    dispatch (type, Message, md);
161 	    /*
162 	     * The message may have caused the need to
163 	     * schedule something, so go back and check.
164 	     */
165 	    return(1);
166     }
167     return(0);
168 }
169 
170 /*
171 ** calculate_nopen() - DETERMINE # FILE DESCRIPTORS AVAILABLE FOR QUEUES
172 */
173 
174 static void
calculate_nopen(void)175 calculate_nopen(void)
176 {
177     int		fd, nopen;
178 
179     /*
180      * How many file descriptorss are currently being used?
181      */
182     for (fd = nopen = 0; fd < OpenMax; fd++)
183 	if (fcntl(fd, F_GETFL, 0) != -1)
184 	    nopen++;
185 
186     /*
187      * How many file descriptors are available for use
188      * as open FIFOs? Leave one spare as a way to tell
189      * clients we don't have any to spare (hmmm....) and
190      * one for the incoming fifo.
191      */
192 
193     MaxClients = OpenMax;
194     MaxClients -= nopen;	/* current overhead */
195     MaxClients -= Reserve_Fds;
196     MaxClients -= 2;		/* incoming FIFO and spare outgoing */
197     MaxClients--;		/* the requests log */
198     MaxClients--;		/* HPI routines and lpsched log */
199 
200     return;
201 }
202 
conn_shutdown()203 static void conn_shutdown ( )
204 {
205     if (!Shutdown) {
206 	note ("The public connection \"%s\", has failed.\n", Lp_FIFO);
207 	lpshut(1);
208     }
209 }
210 
211 /*
212 ** init_messages() - INITIALIZE MAIN MESSAGE QUEUE
213 */
214 
215 void
init_messages(void)216 init_messages(void)
217 {
218     char	*cmd;
219     MESG *	md;
220 
221     (void) signal(SIGPIPE, SIG_IGN);
222 
223     calculate_nopen ();
224 
225     Message = (char *)Malloc(MSGMAX);
226 
227     (void) Chmod(Lp_Tmp, 0711);
228 
229     if ((md = mcreate(Lp_FIFO)) == NULL)
230 	fail ("Can't create public message device (%s).\n", PERROR);
231     mon_discon(md, conn_shutdown);
232 
233     if (mlisteninit(md) != 0)
234 	if (errno == ENOMEM)
235 	    mallocfail();
236 	else
237 	    fail ("Unexpected streams error (%s).\n" , PERROR);
238 
239     (void) Chmod(Lp_FIFO, 0666);
240     return;
241 }
242 
243 
244 void
shutdown_messages(void)245 shutdown_messages(void)
246 {
247     MESG	*md;
248 
249     (void) Chmod(Lp_Tmp, 0700);
250     (void) Chmod(Lp_FIFO, 0600);
251     md = mlistenreset();
252     mdestroy(md);
253 }
254