+/*
+ * Copyright (c) 2000 Silicon Graphics, Inc. All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it would be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * Further, this software is distributed without any warranty that it is
+ * free of the rightful claim of any third person regarding infringement
+ * or the like. Any license provided herein, whether implied or
+ * otherwise, applies only to this software file. Patent licenses, if
+ * any, provided herein do not apply to combinations of this program with
+ * other software, or any other product whatsoever.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write the Free Software Foundation, Inc., 59
+ * Temple Place - Suite 330, Boston MA 02111-1307, USA.
+ *
+ * Contact information: Silicon Graphics, Inc., 1600 Amphitheatre Pkwy,
+ * Mountain View, CA 94043, or:
+ *
+ * http://www.sgi.com
+ *
+ * For further information regarding this notice, see:
+ *
+ * http://oss.sgi.com/projects/GenInfo/NoticeExplan/
+ */
+#ifndef _WRITE_LOG_H_
+#define _WRITE_LOG_H_
+
+/*
+ * Constants defining the max size of various wlog_rec fields. ANY SIZE
+ * CHANGES HERE MUST BE REFLECTED IN THE WLOG_REC_DISK STRUCTURE DEFINED
+ * BELOW.
+ */
+
+#define WLOG_MAX_PATH 128
+#define WLOG_MAX_PATTERN 64
+#define WLOG_MAX_HOST 8
+#define WLOG_REC_MAX_SIZE (sizeof(struct wlog_rec)+WLOG_MAX_PATH+WLOG_MAX_PATTERN+WLOG_MAX_HOST+2)
+
+/*
+ * User view of a write log record. Note that this is not necessiliary
+ * how the data is formatted on disk (signifigant compression occurrs), so
+ * don't expect to od the write log file and see things formatted this way.
+ */
+
+struct wlog_rec {
+ int w_pid; /* pid doing the write */
+ int w_offset; /* file offset */
+ int w_nbytes; /* # bytes written */
+ int w_oflags; /* low-order open() flags */
+ int w_done; /* 1 if io confirmed done */
+ int w_async; /* 1 if async write (writea) */
+
+ char w_host[WLOG_MAX_HOST+1]; /* host doing write - */
+ /* null terminated */
+ int w_hostlen; /* host name length */
+ char w_path[WLOG_MAX_PATH+1]; /* file written to - */
+ /* null terminated */
+ int w_pathlen; /* file name length */
+ char w_pattern[WLOG_MAX_PATTERN+1]; /* pattern written - */
+ /* null terminated */
+ int w_patternlen; /* pattern length */
+};
+
+#ifndef uint
+#define uint unsigned int
+#endif
+
+/*
+ * On-disk structure of a wlog_rec. Actually, the record consists of
+ * 3 parts: [wlog_rec_disk structure][variable length data][length]
+ * where length is a 2 byte field containing the total record length
+ * (including the 2 bytes). It is used for scanning the logfile in reverse
+ * order.
+ *
+ * The variable length data includes the path, host, and pattern (in that
+ * order). The lengths of these pieces of data are held in the
+ * wlog_rec_disk structure. Thus, the actual on-disk record looks like
+ * this (top is lower byte offset):
+ *
+ * struct wlog_rec_disk
+ * path (w_pathlen bytes - not null terminated)
+ * host (w_hostlen bytes - not null terminated)
+ * pattern (w_patternlen bytes - not null terminated)
+ * 2-byte record length
+ *
+ * Another way of looking at it is:
+ *
+ * <struct wlog_rec_disk><path (wpathlen bytes)>-->
+ * --><host (w_hostlen bytes)><pattern (w_patternlen bytes)><length (2 bytes)>
+ *
+ * The maximum length of this record is defined by the WLOG_REC_MAX_SIZE
+ * record. Note that the 2-byte record length forces this to be
+ * <= 64k bytes.
+ *
+ * Note that there is lots of bit-masking done here. The w_pathlen,
+ * w_hostlen, and w_patternlen fields MUST have enough bits to hold
+ * WLOG_MAX_PATH, WLOG_MAX_HOST, and WLOG_MAX_PATTERN bytes respectivly.
+ */
+
+struct wlog_rec_disk {
+#ifdef sgi /* sgi is pissy about fields > 32 bit, even cc -mips3 */
+ uint w_offset : 32; /* file offset */
+ uint w_extra0 : 32; /* EXTRA BITS IN WORD 0 */
+#endif
+#ifdef linux
+ uint w_offset : 32; /* file offset */
+ uint w_extra0 : 32; /* EXTRA BITS IN WORD 0 */
+#endif
+#ifdef CRAY
+ uint w_offset : 44; /* file offset */
+ uint w_extra0 : 20; /* EXTRA BITS IN WORD 0 */
+#endif
+
+ uint w_nbytes : 32; /* # bytes written */
+ uint w_oflags : 32; /* low-order open() flags */
+
+ uint w_pid : 17; /* pid doing the write */
+ uint w_pathlen : 7; /* length of file path */
+ uint w_patternlen: 6; /* length of pattern */
+ uint w_hostlen : 4; /* length of host */
+ uint w_done : 1; /* 1 if io confirmed done */
+ uint w_async : 1; /* 1 if async write (writea) */
+ uint w_extra2 : 28; /* EXTRA BITS IN WORD 2 */
+};
+
+/*
+ * write log file datatype. wlog_open() initializes this structure
+ * which is then passed around to the various wlog_xxx routines.
+ */
+
+struct wlog_file {
+ int w_afd; /* append fd */
+ int w_rfd; /* random-access fd */
+ char w_file[1024]; /* name of the write_log */
+};
+
+/*
+ * return value defines for the user-supplied function to
+ * wlog_scan_backward().
+ */
+
+#define WLOG_STOP_SCAN 0
+#define WLOG_CONTINUE_SCAN 1
+
+/*
+ * wlog prototypes
+ */
+
+#if __STDC__
+extern int wlog_open(struct wlog_file *wfile, int trunc, int mode);
+extern int wlog_close(struct wlog_file *wfile);
+extern int wlog_record_write(struct wlog_file *wfile,
+ struct wlog_rec *wrec, long offset);
+extern int wlog_scan_backward(struct wlog_file *wfile, int nrecs,
+ int (*func)(struct wlog_rec *rec),
+ long data);
+#else
+int wlog_open();
+int wlog_close();
+int wlog_record_write();
+int wlog_scan_backward();
+#endif
+
+extern char Wlog_Error_String[];
+
+#endif /* _WRITE_LOG_H_ */
+
projects / xfstests-dev.git / commitdiff