1*0Sstevel@tonic-gate /*
2*0Sstevel@tonic-gate * CDDL HEADER START
3*0Sstevel@tonic-gate *
4*0Sstevel@tonic-gate * The contents of this file are subject to the terms of the
5*0Sstevel@tonic-gate * Common Development and Distribution License, Version 1.0 only
6*0Sstevel@tonic-gate * (the "License"). You may not use this file except in compliance
7*0Sstevel@tonic-gate * with the License.
8*0Sstevel@tonic-gate *
9*0Sstevel@tonic-gate * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10*0Sstevel@tonic-gate * or http://www.opensolaris.org/os/licensing.
11*0Sstevel@tonic-gate * See the License for the specific language governing permissions
12*0Sstevel@tonic-gate * and limitations under the License.
13*0Sstevel@tonic-gate *
14*0Sstevel@tonic-gate * When distributing Covered Code, include this CDDL HEADER in each
15*0Sstevel@tonic-gate * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16*0Sstevel@tonic-gate * If applicable, add the following below this CDDL HEADER, with the
17*0Sstevel@tonic-gate * fields enclosed by brackets "[]" replaced with your own identifying
18*0Sstevel@tonic-gate * information: Portions Copyright [yyyy] [name of copyright owner]
19*0Sstevel@tonic-gate *
20*0Sstevel@tonic-gate * CDDL HEADER END
21*0Sstevel@tonic-gate */
22*0Sstevel@tonic-gate /* Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
23*0Sstevel@tonic-gate /* All Rights Reserved */
24*0Sstevel@tonic-gate
25*0Sstevel@tonic-gate
26*0Sstevel@tonic-gate #ident "%Z%%M% %I% %E% SMI" /* SVr4.0 1.10 */
27*0Sstevel@tonic-gate /* LINTLIBRARY */
28*0Sstevel@tonic-gate
29*0Sstevel@tonic-gate # include <unistd.h>
30*0Sstevel@tonic-gate # include <errno.h>
31*0Sstevel@tonic-gate # include <string.h>
32*0Sstevel@tonic-gate
33*0Sstevel@tonic-gate # include "lp.h"
34*0Sstevel@tonic-gate # include "msgs.h"
35*0Sstevel@tonic-gate
36*0Sstevel@tonic-gate /*
37*0Sstevel@tonic-gate ** Choose at least one byte that won't appear in the body or header
38*0Sstevel@tonic-gate ** of a message.
39*0Sstevel@tonic-gate */
40*0Sstevel@tonic-gate unsigned char Resync[HEAD_RESYNC_LEN] = { 0x01, 0xFE };
41*0Sstevel@tonic-gate unsigned char Endsync[HEAD_RESYNC_LEN] = { 0x02, 0xFD };
42*0Sstevel@tonic-gate
43*0Sstevel@tonic-gate
44*0Sstevel@tonic-gate /*
45*0Sstevel@tonic-gate ** write_fifo() - WRITE A BUFFER WITH HEADER AND CHECKSUM
46*0Sstevel@tonic-gate */
47*0Sstevel@tonic-gate
48*0Sstevel@tonic-gate #if defined(__STDC__)
write_fifo(int fifo,char * buf,unsigned int size)49*0Sstevel@tonic-gate int write_fifo ( int fifo, char * buf, unsigned int size )
50*0Sstevel@tonic-gate #else
51*0Sstevel@tonic-gate int write_fifo (fifo, buf, size)
52*0Sstevel@tonic-gate int fifo;
53*0Sstevel@tonic-gate char *buf;
54*0Sstevel@tonic-gate unsigned int size;
55*0Sstevel@tonic-gate #endif
56*0Sstevel@tonic-gate {
57*0Sstevel@tonic-gate unsigned short chksum = 0;
58*0Sstevel@tonic-gate int wbytes = 0;
59*0Sstevel@tonic-gate
60*0Sstevel@tonic-gate (void)memcpy (buf + HEAD_RESYNC, Resync, HEAD_RESYNC_LEN);
61*0Sstevel@tonic-gate (void)memcpy (buf + TAIL_ENDSYNC(size), Endsync, TAIL_ENDSYNC_LEN);
62*0Sstevel@tonic-gate
63*0Sstevel@tonic-gate CALC_CHKSUM (buf, size, chksum);
64*0Sstevel@tonic-gate (void)htos (buf + TAIL_CHKSUM(size), chksum);
65*0Sstevel@tonic-gate
66*0Sstevel@tonic-gate
67*0Sstevel@tonic-gate /*
68*0Sstevel@tonic-gate ** A message must be written in one call, to avoid interleaving
69*0Sstevel@tonic-gate ** messages from several processes.
70*0Sstevel@tonic-gate **
71*0Sstevel@tonic-gate ** The caller is responsible for trapping SIGPIPE, so
72*0Sstevel@tonic-gate ** we just return what the "write()" system call does.
73*0Sstevel@tonic-gate **
74*0Sstevel@tonic-gate ** Well, almost. If the pipe was almost full, we may have
75*0Sstevel@tonic-gate ** written a partial message. If this is the case, we lie
76*0Sstevel@tonic-gate ** and say the pipe was full, so the caller can try again.
77*0Sstevel@tonic-gate **
78*0Sstevel@tonic-gate ** read_fifo can deal with a truncated message, so we let it
79*0Sstevel@tonic-gate ** do the grunt work associated with partial messages.
80*0Sstevel@tonic-gate **
81*0Sstevel@tonic-gate ** NOTE: Writing the remainder of the message is not feasible
82*0Sstevel@tonic-gate ** as someone else may have written something to the fifo
83*0Sstevel@tonic-gate ** while we were setting up to retry.
84*0Sstevel@tonic-gate */
85*0Sstevel@tonic-gate
86*0Sstevel@tonic-gate if ((wbytes = write(fifo, buf, size)) > 0)
87*0Sstevel@tonic-gate if (wbytes != size)
88*0Sstevel@tonic-gate return(0);
89*0Sstevel@tonic-gate
90*0Sstevel@tonic-gate return(wbytes);
91*0Sstevel@tonic-gate }
92