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diff --git a/usr.sbin/fifolog/lib/fifolog.h b/usr.sbin/fifolog/lib/fifolog.h
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+/*-
+ * Copyright (c) 2005-2008 Poul-Henning Kamp
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ */
+
+#ifndef __LOCAL_FIFOLOG_H_
+#define __LOCAL_FIFOLOG_H_
+
+/*
+ * Definitions for fifolog "protocol": the on-media layout.
+ *
+ * The fifolog on-media record has three layers:
+ *   The outher timestamping and synchronization layer.
+ *   The zlib implemented data compression
+ *   The inner sequencing and identification layer.
+ *
+ * All three layers are synchronized at a subset of the outher layer
+ * record boundaries, from where reading can be initiated.
+ *
+ *
+ * The outher layer:
+ * -----------------
+ * The first record in a fifolog contains a magic string and version
+ * information along with a 32be encoded recordsize for all records
+ * in the fifolog, including the first.
+ * The recordsize is explicit to avoid ambiguities when a media is
+ * moved from one machine to another.
+ *
+ * Each record in the fifolog has the following contents:
+ *	offset	type	contents
+ *      --------------------------------------------------------------
+ *	0	32be	sequence_number
+ *			The sequence number is randomly chosen for the
+ *			fifolog and increments once for each record written.
+ *			It's precense allow quick identification of the next
+ *			record to be written using a binary search for the
+ *			first place where a discontinuity in the sequence
+ *			numbers occur.
+ *	4	 8	flags (FIFOLOG_FLG_*)
+ *
+ * If (flags & (FIFOLOG_FLG_SYNC)) the record is a synchronization point
+ * at which the inner layers are aligned so that reading can be started
+ * at this point.
+ * To enable seeks into the file based on timestamps, a third field is
+ * present in these records as well:
+ *	5	32be	time_t containing POSIX's understanding of UTC.
+ *
+ * These fields are immediately followed by the inner layer payload as 
+ * described below, which has variable length.
+ *
+ * If the inner layer payload is shorter than the available space in
+ * the record, it is padded with zero bytes, and the number of unused
+ * bytes, including the encoded length thereof is recorded at the end
+ * of the record as follows:
+ *
+ * If (flags & FIFOLOG_FLG_1BYTE)
+ *	n-1	8	number of unused bytes
+ * else if (flags & FIFOLOG_FLG_4BYTE)
+ *	n-4	32be	number of unused bytes
+ *
+ *
+ * The gzip layer
+ * --------------
+ * Is just output from zlib, nothing special here.  FIFOLOG_FLG_SYNC
+ * corresponds to Z_FINISH flags to zlib.
+ * In most cases, the timer will expire before zlib has filled an entire
+ * record in which case Z_SYNC_FLUSH will be used to force as much as
+ * possible into the buffer before it is written.  This is not marked
+ * in outher layer (apart from a natural correlation with padding) since
+ * zlibs data stream handles this without help.
+ *
+ *
+ * The inner layer:
+ * ----------------
+ * The inner layer contains data indentification and to the second 
+ * timestamping (the timestamp in the outherlayer only marks the 
+ * first possible timestamp for content in the SYNC record).
+ * 
+ *	offset	type	contents
+ *      --------------------------------------------------------------
+ *	0	32be	ident
+ *
+ * The bottom 30 bits of the identification word are application defined,
+ * presently unused in the stand-alone fifolog tools, but used in the
+ * original "measured" application that originated the fifolog format.
+ * Should for instance syslogd(8) grow native support for fifolog format,
+ * it could store the message priority here.
+ *
+ * If (ident & FIFOLOG_TIMESTAMP) the record is prefixed by:
+ *	4	32be	time_t containing POSIX's understanding of UTC.
+ *
+ * Then follows the content, either as a NUL terminated string or as
+ * a lenght encoded binary sequence:
+ *
+ * If (ident & FIFOLOG_LENGTH) the record is prefixed by:
+ *	{0|4}	8	length of binary data
+ *
+ */
+
+/* Magic identification string */
+#define FIFOLOG_FMT_MAGIC	"Measured FIFOLOG Ver 1.01\n"
+
+/* Offset of the 32be encoded recordsize in the first sector */
+#define FIFOLOG_OFF_BS		0x20
+
+#define FIFOLOG_FLG_1BYTE	0x01
+#define FIFOLOG_FLG_4BYTE	0x02
+#define FIFOLOG_FLG_RESTART	0x40
+#define FIFOLOG_FLG_SYNC	0x80
+
+#define FIFOLOG_TIMESTAMP	0x80000000
+#define FIFOLOG_LENGTH		0x40000000
+#define FIFOLOG_IDENT		0x3fffffff
+
+#endif /* __LOCAL_FIFOLOG_H_ */