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statd.h revision 1.1 
      1 /*	$NetBSD: statd.h,v 1.1 1997/03/10 06:28:32 scottr Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1995
      5  *	A.R. Gordon (andrew.gordon (at) net-tel.co.uk).  All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  * 3. All advertising materials mentioning features or use of this software
     16  *    must display the following acknowledgement:
     17  *	This product includes software developed for the FreeBSD project
     18  * 4. Neither the name of the author nor the names of any co-contributors
     19  *    may be used to endorse or promote products derived from this software
     20  *    without specific prior written permission.
     21  *
     22  * THIS SOFTWARE IS PROVIDED BY ANDREW GORDON AND CONTRIBUTORS ``AS IS'' AND
     23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     32  * SUCH DAMAGE.
     33  *
     34  */
     35 
     36 #include "sm_inter.h"
     37 
     38 /* ------------------------------------------------------------------------- */
     39 /*
     40  * Data structures for recording monitored hosts
     41  *
     42  * The information held by the status monitor comprises a list of hosts
     43  * that we have been asked to monitor, and, associated with each monitored
     44  * host, one or more clients to be called back if the monitored host crashes.
     45  *
     46  * The list of monitored hosts must be retained over a crash, so that upon
     47  * re-boot we can call the SM_NOTIFY procedure in all those hosts so as to
     48  * cause them to start recovery processing.  On the other hand, the client
     49  * call-backs are not required to be preserved: they are assumed (in the
     50  * protocol design) to be local processes which will have crashed when
     51  * we did, and so are discarded on restart.
     52  *
     53  * We handle this by keeping the list of monitored hosts in a file
     54  * (/var/statd.state) which is mmap()ed and whose format is described
     55  * by the typedef FileLayout.  The lists of client callbacks are chained
     56  * off this structure, but are held in normal memory and so will be
     57  * lost after a re-boot.  Hence the actual values of MonList * pointers
     58  * in the copy on disc have no significance, but their NULL/non-NULL
     59  * status indicates whether this host is actually being monitored or if it
     60  * is an empty slot in the file.
     61  */
     62 
     63 typedef struct MonList_s {
     64 	struct MonList_s *next;		/* Next in list or NULL */
     65 	char	notifyHost[SM_MAXSTRLEN + 1]; /* Host to notify */
     66 	int     notifyProg;		/* RPC program number to call */
     67 	int     notifyVers;		/* version number */
     68 	int     notifyProc;		/* procedure number */
     69 	u_char	notifyData[16];		/* Opaque data from caller */
     70 }       MonList;
     71 
     72 typedef struct {
     73 	char    hostname[SM_MAXSTRLEN + 1]; /* Name of monitored host */
     74 	int     notifyReqd;	/* TRUE if we've crashed and not yet
     75 				   informed the monitored host */
     76 	MonList *monList;	/* List of clients to inform if we
     77 				   hear that the monitored host has
     78 				   crashed, NULL if no longer monitored	 */
     79 }       HostInfo;
     80 
     81 
     82 /* Overall file layout. */
     83 
     84 typedef struct {
     85 	int	ourState;	/* State number as defined in statd protocol */
     86 	int	noOfHosts;	/* Number of elements in hosts[] */
     87 	char	reserved[248];	/* Reserved for future use */
     88 	HostInfo hosts[1];	/* vector of monitored hosts */
     89 }       FileLayout;
     90 #define	HEADER_LEN (sizeof(FileLayout) - sizeof(HostInfo))
     91 
     92 /* ------------------------------------------------------------------------- */
     93 
     94 /* Global variables */
     95 
     96 extern FileLayout *status_info;	/* The mmap()ed status file */
     97 extern int	debug;		/* = 1 to enable diagnostics to syslog */
     98 
     99 /* Function prototypes */
    100 
    101 extern HostInfo	*find_host __P((char *hostname, int create));
    102 extern void	init_file __P((char *filename));
    103 extern void	notify_hosts __P((void));
    104 extern void	sync_file __P((void));
    105