summaryrefslogtreecommitdiff
path: root/usr/src/cmd/lp/lib/msgs/read_fifo.c
diff options
context:
space:
mode:
Diffstat (limited to 'usr/src/cmd/lp/lib/msgs/read_fifo.c')
-rw-r--r--usr/src/cmd/lp/lib/msgs/read_fifo.c366
1 files changed, 0 insertions, 366 deletions
diff --git a/usr/src/cmd/lp/lib/msgs/read_fifo.c b/usr/src/cmd/lp/lib/msgs/read_fifo.c
deleted file mode 100644
index c30e39ba97..0000000000
--- a/usr/src/cmd/lp/lib/msgs/read_fifo.c
+++ /dev/null
@@ -1,366 +0,0 @@
-/*
- * CDDL HEADER START
- *
- * The contents of this file are subject to the terms of the
- * Common Development and Distribution License, Version 1.0 only
- * (the "License"). You may not use this file except in compliance
- * with the License.
- *
- * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
- * or http://www.opensolaris.org/os/licensing.
- * See the License for the specific language governing permissions
- * and limitations under the License.
- *
- * When distributing Covered Code, include this CDDL HEADER in each
- * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
- * If applicable, add the following below this CDDL HEADER, with the
- * fields enclosed by brackets "[]" replaced with your own identifying
- * information: Portions Copyright [yyyy] [name of copyright owner]
- *
- * CDDL HEADER END
- */
-/*
- * Copyright 2005 Sun Microsystems, Inc. All rights reserved.
- * Use is subject to license terms.
- */
-
-/* Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
-/* All Rights Reserved */
-
-#pragma ident "%Z%%M% %I% %E% SMI"
-
-/* LINTLIBRARY */
-
-# include <errno.h>
-# include <string.h>
-#include <syslog.h>
-
-# include "lp.h"
-# include "msgs.h"
-
-extern char Resync[];
-extern char Endsync[];
-static int Had_Full_Buffer = 1;
-int Garbage_Bytes = 0;
-int Garbage_Messages= 0;
-
-static int _buffer(int);
-
-/*
-** A real message is written in one piece, and the write
-** is atomic. Thus, even if the O_NDELAY flag is set,
-** if we read part of the real message, we can continue
-** to read the rest of it in as many steps as we want
-** (up to the size of the message, of course!) without
-** UNIX returning 0 because no data is available.
-** So, a real message doesn't have to be read in one piece,
-** which is good since we don't know how much to read!
-**
-** Fake messages, or improperly written messages, don't
-** have this nice property.
-**
-** INTERRUPTED READS:
-**
-** If a signal occurs during an attempted read, we can exit.
-** The caller can retry the read and we will correctly restart
-** it. The correctness of this assertion can be seen by noticing
-** that at the beginning of each READ below, we can go back
-** to the first statement executed (the first READ below)
-** and correctly reexecute the code.
-**
-** If the last writer closed the fifo, we'll read 0 bytes
-** (at least on the subsequent read). If we were in the
-** middle of reading a message, we were reading a bogus
-** message (but see below).
-**
-** If we read less than we expect, it's because we were
-** reading a fake message (but see below).
-**
-** HOWEVER: In the last two cases, we may have ONE OR MORE
-** REAL MESSAGES snuggled in amongst the trash!
-**
-** All this verbal rambling is preface to let you understand why we
-** buffer the data (which is a shame, but necessary).
-*/
-
-/*
-** As long as we get real messages, we can avoid needless function calls.
-** The SYNC argument in this macro should be set if the resynch. bytes
-** have been read--i.e. if the rest of the message is trying to be read.
-** In this case, if we had not read a full buffer last time, then we
-** must be in the middle of a bogus message.
-*/
-
-#define UNSYNCHED_READ(N) \
- if (fbp->psave_end - fbp->psave < N || fbp->psave >= fbp->psave_end) \
- { \
- switch (_buffer(fifo)) \
- { \
- case -1: \
- return (-1); \
- case 0: \
- if (fbp->psave_end > fbp->psave) \
- goto SyncUp; \
- return (0); \
- } \
- }
-
-#define SYNCHED_READ(N) \
- if (fbp->psave_end - fbp->psave < N || fbp->psave >= fbp->psave_end) \
- { \
- switch (_buffer(fifo)) \
- { \
- case -1: \
- return (-1); \
- case 0: \
- if (fbp->psave_end > fbp->psave) \
- goto SyncUp; \
- return (0); \
- } \
- if (!Had_Full_Buffer) \
- goto SyncUp; \
- }
-
-/*
-** read_fifo() - READ A BUFFER WITH HEADER AND CHECKSUM
-*/
-int
-read_fifo (fifo, buf, size)
-int fifo;
-char *buf;
-unsigned int size;
-{
- register fifobuffer_t *fbp;
- register unsigned int real_chksum,
- chksum,
- real_size;
-
- /*
- ** Make sure we start on a message boundary. The first
- ** line of defense is to look for the resync. bytes.
- **
- ** The "SyncUp" label is global to this routine (below this point)
- ** and is called whenever we determine that we're out
- ** of sync. with the incoming bytes.
- */
-
- if (!(fbp=GetFifoBuffer (fifo)))
- return -1;
-
- UNSYNCHED_READ (HEAD_RESYNC_LEN);
- while (*fbp->psave != Resync[0] || *(fbp->psave + 1) != Resync[1])
- {
-SyncUp:
-#if defined(TRACE_MESSAGES)
- if (trace_messages)
- syslog(LOG_DEBUG, "DISCARD %c\n", *fbp->psave);
-#endif
- fbp->psave++;
- Garbage_Bytes++;
- UNSYNCHED_READ (HEAD_RESYNC_LEN);
- }
-
-
- /*
- ** We're sync'd, so read the full header.
- */
-
- SYNCHED_READ (HEAD_LEN);
-
-
- /*
- ** If the header size is smaller than the minimum size for a header,
- ** or larger than allowed, we must assume that we really aren't
- ** synchronized.
- */
-
- real_size = stoh(fbp->psave + HEAD_SIZE);
- if (real_size < CONTROL_LEN || MSGMAX < real_size)
- {
-#if defined(TRACE_MESSAGES)
- if (trace_messages)
- syslog(LOG_DEBUG, "BAD SIZE\n");
-#endif
- goto SyncUp;
- }
-
- /*
- ** We have the header. Now we can finally read the rest of the
- ** message...
- */
-
- SYNCHED_READ (real_size);
-
-
- /*
- ** ...but did we read a real message?...
- */
-
- if
- (
- *(fbp->psave + TAIL_ENDSYNC(real_size)) != Endsync[0]
- || *(fbp->psave + TAIL_ENDSYNC(real_size) + 1) != Endsync[1]
- )
- {
-#if defined(TRACE_MESSAGES)
- if (trace_messages)
- syslog(LOG_DEBUG, "BAD ENDSYNC\n");
-#endif
- Garbage_Messages++;
- goto SyncUp;
- }
-
- chksum = stoh(fbp->psave + TAIL_CHKSUM(real_size));
- CALC_CHKSUM (fbp->psave, real_size, real_chksum);
- if (real_chksum != chksum)
- {
-#if defined(TRACE_MESSAGES)
- if (trace_messages)
- syslog(LOG_DEBUG, "BAD CHKSUM\n");
-#endif
- Garbage_Messages++;
- goto SyncUp;
- }
-
- /*
- ** ...yes!...but can the caller handle the message?
- */
-
- if (size < real_size)
- {
- errno = E2BIG;
- return (-1);
- }
-
-
- /*
- ** Yes!! We can finally copy the message into the caller's buffer
- ** and remove it from our buffer. That wasn't so bad, was it?
- */
-
-#if defined(TRACE_MESSAGES)
- if (trace_messages)
- syslog(LOG_DEBUG, "MESSAGE: %-.*s", real_size, fbp->psave);
-#endif
- (void)memcpy (buf, fbp->psave, real_size);
- fbp->psave += real_size;
- return (real_size);
-}
-
-int
-peek3_2 (fifo)
-int fifo;
-{
- register fifobuffer_t *fbp;
- register unsigned int real_size;
-
- /*
- ** Make sure we start on a message boundary. The first
- ** line of defense is to look for the resync. bytes.
- **
- ** The "SyncUp" label is global to this routine (below this point)
- ** and is called whenever we determine that we're out
- ** of sync. with the incoming bytes.
- */
-
- if (!(fbp=GetFifoBuffer (fifo)))
- return -1;
- UNSYNCHED_READ (HEAD_RESYNC_LEN);
- while (*fbp->psave != Resync[0] || *(fbp->psave + 1) != Resync[1])
- {
-SyncUp:
- fbp->psave++;
- Garbage_Bytes++;
- UNSYNCHED_READ (HEAD_RESYNC_LEN);
- }
-
-
- /*
- ** We're sync'd, so read the full header.
- */
-
- SYNCHED_READ (HEAD_LEN);
-
-
- /*
- ** If the header size is smaller than the minimum size for a header,
- ** or larger than allowed, we must assume that we really aren't
- ** synchronized.
- */
-
- real_size = stoh(fbp->psave + HEAD_SIZE);
- if (real_size < CONTROL_LEN || MSGMAX < real_size)
- {
- goto SyncUp;
- }
-
- return(real_size);
-}
-
-static int
-_buffer(int fifo)
-{
- int n, nbytes, count = 0;
- register fifobuffer_t *fbp;
-
- /*
- ** As long as we get real messages, and if we chose
- ** SAVE_SIZE well, we shouldn't have to move the data
- ** in the "else" branch below: Each time we call "read"
- ** we aren't likely to get as many bytes as we ask for,
- ** just as many as are in the fifo, AND THIS SHOULD
- ** REPRESENT AN INTEGRAL NUMBER OF MESSAGES. Since
- ** the "read_fifo" routine reads complete messages,
- ** it will end its read at the end of the message,
- ** which (eventually) will make "psave_end" == "psave".
- */
-
- /*
- ** If the buffer is empty, there's nothing to move.
- */
- if (!(fbp = GetFifoBuffer (fifo)))
- return -1;
- if (fbp->psave_end == fbp->psave)
- fbp->psave = fbp->psave_end = fbp->save; /* sane pointers! */
-
- /*
- ** If the buffer has data at the high end, move it down.
- */
- else
- if (fbp->psave != fbp->save) /* sane pointers! */
- {
- /*
- ** Move the data still left in the buffer to the
- ** front, so we can read as much as possible into
- ** buffer after it.
- */
-
- memmove(fbp->save, fbp->psave, fbp->psave_end - fbp->psave);
-
- fbp->psave_end = fbp->save + (fbp->psave_end - fbp->psave);
- fbp->psave = fbp->save; /* sane pointers! */
- }
-
- /*
- ** The "fbp->psave" and "fbp->psave_end" pointers must be in a sane
- ** state when we get here, in case the "read()" gets interrupted.
- ** When that happens, we return to the caller who may try
- ** to restart us! Sane: fbp->psave == fbp->save (HERE!)
- */
-
- nbytes = MSGMAX - (fbp->psave_end - fbp->save);
-
- while ((n = read(fifo, fbp->psave_end, nbytes)) == 0 && count < 60)
- {
- (void) sleep ((unsigned) 1);
- count++;
- }
-
- if (n > 0)
- fbp->psave_end += n;
-
- Had_Full_Buffer = fbp->full;
- fbp->full = (nbytes == n);
-
- return (n);
-}
generated by cgit v1.2.3 (git 2.46.0) at 2025-10-12 19:57:52 +0000