xref: /illumos-gate/usr/src/cmd/lp/lib/msgs/mread.c (revision c53bc7580e97f4b1a0c45f1c9734144ae93c52b5)
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 /*	Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T	*/
23 /*	  All Rights Reserved  	*/
24 
25 
26 #ident	"%Z%%M%	%I%	%E% SMI"	/* SVr4.0 1.6	*/
27 /* LINTLIBRARY */
28 
29 
30 #include <errno.h>
31 #include <fcntl.h>
32 #include <string.h>
33 #include <stropts.h>
34 
35 #include "lp.h"
36 #include "msgs.h"
37 
38 extern int	Lp_prio_msg;
39 
40 /*
41 **	Function:	int mread( MESG *, char *, int)
42 **	Args:		message descriptor
43 **			message buffer (var)
44 **			buffer size
45 **	Return:		The size of the message in message buffer.
46 **			or -1 on error.  Possible errnos are:
47 **		EINVAL	Bad value for md or msgbuf.
48 **		E2BIG	Not enough space for message.
49 **		EPIPE	Far end dropped the connection.
50 **		ENOMSG	No valid message available on fifo.
51 **
52 **	mread examines message descriptor and either calls read3_2
53 **	to read 3.2 HPI messages or getmsg(2) to read 4.0 HPI messages.
54 **	If a message is read, it is returned in message buffer.
55 */
56 
57 #if	defined(__STDC__)
58 int mread ( MESG * md, char * msgbuf, int size )
59 #else
60 int mread ( md, msgbuf, size )
61 MESG	*md;
62 char	*msgbuf;
63 int	size;
64 #endif
65 {
66     int			flag = 0;
67     char		buff [MSGMAX];
68     struct strbuf	dat;
69     struct strbuf	ctl;
70 
71     if (md == NULL || msgbuf == NULL)
72     {
73 	errno = EINVAL;
74 	return(-1);
75     }
76 
77     switch(md->type)
78     {
79       case MD_CHILD:
80       case MD_STREAM:
81       case MD_BOUND:
82 	if (size <= 0)
83 	{
84 	    errno = E2BIG;
85 	    return(-1);
86 	}
87 	dat.buf = msgbuf;
88 	dat.maxlen = size;
89 	dat.len = 0;
90 	ctl.buf = buff;
91 	ctl.maxlen = sizeof (buff);
92 	ctl.len = 0;
93 	flag = Lp_prio_msg;
94 	Lp_prio_msg = 0;	/* clean this up so there are no surprises */
95 
96 	if (Getmsg(md, &ctl, &dat, &flag) < 0)
97 	{
98 	    if (errno == EBADF)
99 		errno = EPIPE;
100 	    return(-1);
101 	}
102 
103 	if (dat.len == 0)
104 	{
105 	    (void) Close(md->readfd);
106 	    return(0);
107 	}
108 	break;
109 
110       case MD_USR_FIFO:
111       case MD_SYS_FIFO:
112 	if (size < CONTROL_LEN)
113 	{
114 	    errno = E2BIG;
115 	    return(-1);
116 	}
117 
118 	if (read3_2(md, msgbuf, size) < 0)
119 	    return(-1);
120 	break;
121     }
122 
123     return((int)msize(msgbuf));
124 }
125