rep_region.c

这是国外的resip协议栈

/*-
 * See the file LICENSE for redistribution information.
 *
 * Copyright (c) 2001-2004
 *	Sleepycat Software.  All rights reserved.
 *
 * $Id: rep_region.c,v 1.53 2004/10/15 16:59:44 bostic Exp $
 */

#include "db_config.h"

#ifndef NO_SYSTEM_INCLUDES
#if TIME_WITH_SYS_TIME
#include <sys/time.h>
#include <time.h>
#else
#if HAVE_SYS_TIME_H
#include <sys/time.h>
#else
#include <time.h>
#endif
#endif

#include <string.h>
#endif

#include "db_int.h"
#include "dbinc/db_page.h"
#include "dbinc/log.h"
#include "dbinc/db_am.h"

static int __rep_egen_init  __P((DB_ENV *, REP *));

/*
 * __rep_region_init --
 *	Initialize the shared memory state for the replication system.
 *
 * PUBLIC: int __rep_region_init __P((DB_ENV *));
 */
int
__rep_region_init(dbenv)
	DB_ENV *dbenv;
{
	REGENV *renv;
	REGINFO *infop;
	DB_MUTEX *db_mutexp;
	DB_REP *db_rep;
	REP *rep;
	int ret;

	db_rep = dbenv->rep_handle;
	infop = dbenv->reginfo;
	renv = infop->primary;
	ret = 0;

	MUTEX_LOCK(dbenv, &renv->mutex);
	if (renv->rep_off == INVALID_ROFF) {
		/* Must create the region. */
		if ((ret =
		    __db_shalloc(infop, sizeof(REP), MUTEX_ALIGN, &rep)) != 0)
			goto err;
		memset(rep, 0, sizeof(*rep));
		rep->tally_off = INVALID_ROFF;
		rep->v2tally_off = INVALID_ROFF;
		renv->rep_off = R_OFFSET(infop, rep);

		if ((ret = __db_mutex_setup(dbenv, infop, &rep->mutex,
		    MUTEX_NO_RECORD)) != 0)
			goto err;

		/*
		 * We must create a place for the db_mutex separately;
		 * mutexes have to be aligned to MUTEX_ALIGN, and the only way
		 * to guarantee that is to make sure they're at the beginning
		 * of a shalloc'ed chunk.
		 */
		if ((ret = __db_shalloc(infop, sizeof(DB_MUTEX),
		    MUTEX_ALIGN, &db_mutexp)) != 0)
			goto err;
		rep->db_mutex_off = R_OFFSET(infop, db_mutexp);

		/*
		 * Because we have no way to prevent deadlocks and cannot log
		 * changes made to it, we single-thread access to the client
		 * bookkeeping database.  This is suboptimal, but it only gets
		 * accessed when messages arrive out-of-order, so it should
		 * stay small and not be used in a high-performance app.
		 */
		if ((ret = __db_mutex_setup(dbenv, infop, db_mutexp,
		    MUTEX_NO_RECORD)) != 0)
			goto err;

		/* We have the region; fill in the values. */
		rep->eid = DB_EID_INVALID;
		rep->master_id = DB_EID_INVALID;
		rep->gen = 0;
		if ((ret = __rep_egen_init(dbenv, rep)) != 0)
			goto err;
		/*
		 * Set default values for the min and max log records that we
		 * wait before requesting a missing log record.
		 */
		rep->request_gap = DB_REP_REQUEST_GAP;
		rep->max_gap = DB_REP_MAX_GAP;
		F_SET(rep, REP_F_NOARCHIVE);
		(void)time(&renv->rep_timestamp);
	} else
		rep = R_ADDR(infop, renv->rep_off);
	MUTEX_UNLOCK(dbenv, &renv->mutex);

	db_rep->rep_mutexp = &rep->mutex;
	db_rep->db_mutexp = R_ADDR(infop, rep->db_mutex_off);
	db_rep->region = rep;

	return (0);

err:	MUTEX_UNLOCK(dbenv, &renv->mutex);
	return (ret);
}

/*
 * __rep_region_destroy --
 *	Destroy any system resources allocated in the replication region.
 *
 * PUBLIC: int __rep_region_destroy __P((DB_ENV *));
 */
int
__rep_region_destroy(dbenv)
	DB_ENV *dbenv;
{
	DB_REP *db_rep;
	int ret, t_ret;

	ret = t_ret = 0;
	db_rep = dbenv->rep_handle;

	if (db_rep != NULL) {
		if (db_rep->rep_mutexp != NULL)
			ret = __db_mutex_destroy(db_rep->rep_mutexp);
		if (db_rep->db_mutexp != NULL)
			t_ret = __db_mutex_destroy(db_rep->db_mutexp);
	}

	return (ret == 0 ? t_ret : ret);
}

/*
 * __rep_dbenv_refresh --
 *	Replication-specific refresh of the DB_ENV structure.
 *
 * PUBLIC: void __rep_dbenv_refresh __P((DB_ENV *));
 */
void
__rep_dbenv_refresh(dbenv)
	DB_ENV *dbenv;
{
	if (REP_ON(dbenv))
		((DB_REP *)dbenv->rep_handle)->region = NULL;
	return;
}

/*
 * __rep_dbenv_close --
 *	Replication-specific destruction of the DB_ENV structure.
 *
 * PUBLIC: int __rep_dbenv_close __P((DB_ENV *));
 */
int
__rep_dbenv_close(dbenv)
	DB_ENV *dbenv;
{
	if (REP_ON(dbenv)) {
		__os_free(dbenv, dbenv->rep_handle);
		dbenv->rep_handle = NULL;
		dbenv->rep_send = NULL;
	}

	return (0);
}

/*
 * __rep_preclose --
 *	If we are a client, shut down our client database and, if we're
 * actually closing the environment, close all databases we've opened
 * while applying messages.
 *
 * PUBLIC: int __rep_preclose __P((DB_ENV *, int));
 */
int
__rep_preclose(dbenv, do_closefiles)
	DB_ENV *dbenv;
	int do_closefiles;
{
	DB_REP *db_rep;
	int ret, t_ret;

	ret = 0;

	db_rep = dbenv->rep_handle;
	MUTEX_LOCK(dbenv, db_rep->db_mutexp);
	if (db_rep->rep_db != NULL) {
		ret = __db_close(db_rep->rep_db, NULL, DB_NOSYNC);
		db_rep->rep_db = NULL;
	}

	if (do_closefiles) {
		if ((t_ret = __dbreg_close_files(dbenv)) != 0 && ret == 0)
			ret = t_ret;
		F_CLR(db_rep, DBREP_OPENFILES);
	}
	MUTEX_UNLOCK(dbenv, db_rep->db_mutexp);
	return (ret);
}

/*
 * __rep_egen_init --
 *	Initialize the value of egen in the region.  Called
 * only from __rep_region_init, which is guaranteed to be
 * single-threaded as we create the rep region.  We set the
 * rep->egen field which is normally protected by db_rep->rep_mutex.
 */
static int
__rep_egen_init(dbenv, rep)
	DB_ENV *dbenv;
	REP *rep;
{
	DB_FH *fhp;
	int ret;
	size_t cnt;
	char *p;
#ifdef DIAGNOSTIC
	DB_MSGBUF mb;
#endif

	if ((ret =
	    __db_appname(dbenv, DB_APP_NONE, REP_EGENNAME, 0, NULL, &p)) != 0)
		return (ret);
	/*
	 * If the file doesn't exist, create it now and initialize with 1.
	 */
	if (__os_exists(p, NULL) != 0) {
		rep->egen = rep->gen + 1;
		if ((ret = __rep_write_egen(dbenv, rep->egen)) != 0)
			goto err;
	} else {
		/*
		 * File exists, open it and read in our egen.
		 */
		if ((ret = __os_open(dbenv, p, DB_OSO_RDONLY,
		    __db_omode("rw----"), &fhp)) != 0)
			goto err;
		if ((ret = __os_read(dbenv, fhp, &rep->egen, sizeof(u_int32_t),
		    &cnt)) < 0 || cnt == 0)
			goto err1;
		RPRINT(dbenv, rep, (dbenv, &mb, "Read in egen %lu",
		    (u_long)rep->egen));
err1:		 (void)__os_closehandle(dbenv, fhp);
	}
err:	__os_free(dbenv, p);
	return (ret);
}

/*
 * __rep_write_egen --
 *	Write out the egen into the env file.
 *
 * PUBLIC: int __rep_write_egen __P((DB_ENV *, u_int32_t));
 */
int
__rep_write_egen(dbenv, egen)
	DB_ENV *dbenv;
	u_int32_t egen;
{
	DB_FH *fhp;
	int ret;
	size_t cnt;
	char *p;

	if ((ret =
	    __db_appname(dbenv, DB_APP_NONE, REP_EGENNAME, 0, NULL, &p)) != 0)
		return (ret);
	if ((ret = __os_open(dbenv, p, DB_OSO_CREATE | DB_OSO_TRUNC,
	    __db_omode("rw----"), &fhp)) == 0) {
		if ((ret = __os_write(dbenv, fhp, &egen, sizeof(u_int32_t),
		    &cnt)) != 0 || ((ret = __os_fsync(dbenv, fhp)) != 0))
			__db_err(dbenv, "%s: %s", p, db_strerror(ret));
		(void)__os_closehandle(dbenv, fhp);
	}
	__os_free(dbenv, p);
	return (ret);
}