170 lines
5.9 KiB
C
170 lines
5.9 KiB
C
/*
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* Copyright (c) 2000 Silicon Graphics, Inc. All Rights Reserved.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of version 2 of the GNU General Public License as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it would be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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*
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* Further, this software is distributed without any warranty that it is
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* free of the rightful claim of any third person regarding infringement
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* or the like. Any license provided herein, whether implied or
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* otherwise, applies only to this software file. Patent licenses, if
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* any, provided herein do not apply to combinations of this program with
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* other software, or any other product whatsoever.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write the Free Software Foundation, Inc., 59
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* Temple Place - Suite 330, Boston MA 02111-1307, USA.
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*
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* Contact information: Silicon Graphics, Inc., 1600 Amphitheatre Pkwy,
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* Mountain View, CA 94043, or:
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*
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* http://www.sgi.com
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*
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* For further information regarding this notice, see:
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*
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* http://oss.sgi.com/projects/GenInfo/NoticeExplan/
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*/
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#ifndef _WRITE_LOG_H_
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#define _WRITE_LOG_H_
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/*
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* Constants defining the max size of various wlog_rec fields. ANY SIZE
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* CHANGES HERE MUST BE REFLECTED IN THE WLOG_REC_DISK STRUCTURE DEFINED
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* BELOW.
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*/
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#define WLOG_MAX_PATH 128
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#define WLOG_MAX_PATTERN 64
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#define WLOG_MAX_HOST 8
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#define WLOG_REC_MAX_SIZE (sizeof(struct wlog_rec)+WLOG_MAX_PATH+WLOG_MAX_PATTERN+WLOG_MAX_HOST+2)
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/*
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* User view of a write log record. Note that this is not necessiliary
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* how the data is formatted on disk (signifigant compression occurrs), so
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* don't expect to od the write log file and see things formatted this way.
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*/
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struct wlog_rec {
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int w_pid; /* pid doing the write */
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int w_offset; /* file offset */
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int w_nbytes; /* # bytes written */
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int w_oflags; /* low-order open() flags */
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int w_done; /* 1 if io confirmed done */
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int w_async; /* 1 if async write (writea) */
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char w_host[WLOG_MAX_HOST+1]; /* host doing write - */
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/* null terminated */
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int w_hostlen; /* host name length */
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char w_path[WLOG_MAX_PATH+1]; /* file written to - */
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/* null terminated */
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int w_pathlen; /* file name length */
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char w_pattern[WLOG_MAX_PATTERN+1]; /* pattern written - */
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/* null terminated */
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int w_patternlen; /* pattern length */
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};
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#ifndef uint
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#define uint unsigned int
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#endif
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/*
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* On-disk structure of a wlog_rec. Actually, the record consists of
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* 3 parts: [wlog_rec_disk structure][variable length data][length]
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* where length is a 2 byte field containing the total record length
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* (including the 2 bytes). It is used for scanning the logfile in reverse
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* order.
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*
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* The variable length data includes the path, host, and pattern (in that
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* order). The lengths of these pieces of data are held in the
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* wlog_rec_disk structure. Thus, the actual on-disk record looks like
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* this (top is lower byte offset):
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*
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* struct wlog_rec_disk
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* path (w_pathlen bytes - not null terminated)
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* host (w_hostlen bytes - not null terminated)
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* pattern (w_patternlen bytes - not null terminated)
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* 2-byte record length
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*
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* Another way of looking at it is:
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*
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* <struct wlog_rec_disk><path (wpathlen bytes)>-->
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* --><host (w_hostlen bytes)><pattern (w_patternlen bytes)><length (2 bytes)>
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*
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* The maximum length of this record is defined by the WLOG_REC_MAX_SIZE
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* record. Note that the 2-byte record length forces this to be
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* <= 64k bytes.
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*
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* Note that there is lots of bit-masking done here. The w_pathlen,
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* w_hostlen, and w_patternlen fields MUST have enough bits to hold
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* WLOG_MAX_PATH, WLOG_MAX_HOST, and WLOG_MAX_PATTERN bytes respectivly.
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*/
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struct wlog_rec_disk {
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#ifdef CRAY
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uint w_offset : 44; /* file offset */
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uint w_extra0 : 20; /* EXTRA BITS IN WORD 0 */
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#else
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uint w_offset : 32; /* file offset */
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uint w_extra0 : 32; /* EXTRA BITS IN WORD 0 */
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#endif
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uint w_nbytes : 32; /* # bytes written */
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uint w_oflags : 32; /* low-order open() flags */
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uint w_pid : 17; /* pid doing the write */
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uint w_pathlen : 7; /* length of file path */
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uint w_patternlen: 6; /* length of pattern */
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uint w_hostlen : 4; /* length of host */
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uint w_done : 1; /* 1 if io confirmed done */
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uint w_async : 1; /* 1 if async write (writea) */
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uint w_extra2 : 28; /* EXTRA BITS IN WORD 2 */
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};
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/*
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* write log file datatype. wlog_open() initializes this structure
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* which is then passed around to the various wlog_xxx routines.
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*/
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struct wlog_file {
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int w_afd; /* append fd */
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int w_rfd; /* random-access fd */
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char w_file[1024]; /* name of the write_log */
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};
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/*
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* return value defines for the user-supplied function to
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* wlog_scan_backward().
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*/
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#define WLOG_STOP_SCAN 0
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#define WLOG_CONTINUE_SCAN 1
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/*
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* wlog prototypes
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*/
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#if __STDC__
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extern int wlog_open(struct wlog_file *wfile, int trunc, int mode);
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extern int wlog_close(struct wlog_file *wfile);
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extern int wlog_record_write(struct wlog_file *wfile,
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struct wlog_rec *wrec, long offset);
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extern int wlog_scan_backward(struct wlog_file *wfile, int nrecs,
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int (*func)(struct wlog_rec *rec),
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long data);
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#else
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int wlog_open();
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int wlog_close();
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int wlog_record_write();
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int wlog_scan_backward();
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#endif
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extern char Wlog_Error_String[];
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#endif /* _WRITE_LOG_H_ */
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