log_get.c

这是国外的resip协议栈

/*-
 * See the file LICENSE for redistribution information.
 *
 * Copyright (c) 1996-2004
 *	Sleepycat Software.  All rights reserved.
 *
 * $Id: log_get.c,v 11.110 2004/09/17 22:00:31 mjc Exp $
 */

#include "db_config.h"

#ifndef NO_SYSTEM_INCLUDES
#include <sys/types.h>

#include <string.h>
#endif

#include "db_int.h"
#include "dbinc/crypto.h"
#include "dbinc/db_page.h"
#include "dbinc/hmac.h"
#include "dbinc/log.h"
#include "dbinc/hash.h"

typedef enum { L_ALREADY, L_ACQUIRED, L_NONE } RLOCK;

static int __log_c_close_pp __P((DB_LOGC *, u_int32_t));
static int __log_c_get_pp __P((DB_LOGC *, DB_LSN *, DBT *, u_int32_t));
static int __log_c_get_int __P((DB_LOGC *, DB_LSN *, DBT *, u_int32_t));
static int __log_c_hdrchk __P((DB_LOGC *, DB_LSN *, HDR *, int *));
static int __log_c_incursor __P((DB_LOGC *, DB_LSN *, HDR *, u_int8_t **));
static int __log_c_inregion __P((DB_LOGC *,
	       DB_LSN *, RLOCK *, DB_LSN *, HDR *, u_int8_t **));
static int __log_c_io __P((DB_LOGC *,
	       u_int32_t, u_int32_t, void *, size_t *, int *));
static int __log_c_ondisk __P((DB_LOGC *,
	       DB_LSN *, DB_LSN *, u_int32_t, HDR *, u_int8_t **, int *));
static int __log_c_set_maxrec __P((DB_LOGC *, char *));
static int __log_c_shortread __P((DB_LOGC *, DB_LSN *, int));

/*
 * __log_cursor_pp --
 *	DB_ENV->log_cursor
 *
 * PUBLIC: int __log_cursor_pp __P((DB_ENV *, DB_LOGC **, u_int32_t));
 */
int
__log_cursor_pp(dbenv, logcp, flags)
	DB_ENV *dbenv;
	DB_LOGC **logcp;
	u_int32_t flags;
{
	int rep_check, ret;

	PANIC_CHECK(dbenv);
	ENV_REQUIRES_CONFIG(dbenv,
	    dbenv->lg_handle, "DB_ENV->log_cursor", DB_INIT_LOG);

	/* Validate arguments. */
	if ((ret = __db_fchk(dbenv, "DB_ENV->log_cursor", flags, 0)) != 0)
		return (ret);

	rep_check = IS_ENV_REPLICATED(dbenv) ? 1 : 0;
	if (rep_check)
		__env_rep_enter(dbenv);
	ret = __log_cursor(dbenv, logcp);
	if (rep_check)
		__env_db_rep_exit(dbenv);
	return (ret);
}

/*
 * __log_cursor --
 *	Create a log cursor.
 *
 * PUBLIC: int __log_cursor __P((DB_ENV *, DB_LOGC **));
 */
int
__log_cursor(dbenv, logcp)
	DB_ENV *dbenv;
	DB_LOGC **logcp;
{
	DB_LOGC *logc;
	int ret;

	*logcp = NULL;

	/* Allocate memory for the cursor. */
	if ((ret = __os_calloc(dbenv, 1, sizeof(DB_LOGC), &logc)) != 0)
		return (ret);

	logc->bp_size = DB_LOGC_BUF_SIZE;
	/*
	 * Set this to something positive.
	 */
	logc->bp_maxrec = MEGABYTE;
	if ((ret = __os_malloc(dbenv, logc->bp_size, &logc->bp)) != 0) {
		__os_free(dbenv, logc);
		return (ret);
	}

	logc->dbenv = dbenv;
	logc->close = __log_c_close_pp;
	logc->get = __log_c_get_pp;

	*logcp = logc;
	return (0);
}

/*
 * __log_c_close_pp --
 *	DB_LOGC->close pre/post processing.
 */
static int
__log_c_close_pp(logc, flags)
	DB_LOGC *logc;
	u_int32_t flags;
{
	DB_ENV *dbenv;
	int rep_check, ret;

	dbenv = logc->dbenv;

	PANIC_CHECK(dbenv);
	if ((ret = __db_fchk(dbenv, "DB_LOGC->close", flags, 0)) != 0)
		return (ret);

	rep_check = IS_ENV_REPLICATED(dbenv) ? 1 : 0;
	if (rep_check)
		__env_rep_enter(dbenv);
	ret = __log_c_close(logc);
	if (rep_check)
		__env_db_rep_exit(dbenv);
	return (ret);
}

/*
 * __log_c_close --
 *	DB_LOGC->close.
 *
 * PUBLIC: int __log_c_close __P((DB_LOGC *));
 */
int
__log_c_close(logc)
	DB_LOGC *logc;
{
	DB_ENV *dbenv;

	dbenv = logc->dbenv;

	if (logc->c_fhp != NULL) {
		(void)__os_closehandle(dbenv, logc->c_fhp);
		logc->c_fhp = NULL;
	}

	if (logc->c_dbt.data != NULL)
		__os_free(dbenv, logc->c_dbt.data);

	__os_free(dbenv, logc->bp);
	__os_free(dbenv, logc);

	return (0);
}

/*
 * __log_c_get_pp --
 *	DB_LOGC->get pre/post processing.
 */
static int
__log_c_get_pp(logc, alsn, dbt, flags)
	DB_LOGC *logc;
	DB_LSN *alsn;
	DBT *dbt;
	u_int32_t flags;
{
	DB_ENV *dbenv;
	int rep_check, ret;

	dbenv = logc->dbenv;

	PANIC_CHECK(dbenv);

	/* Validate arguments. */
	switch (flags) {
	case DB_CURRENT:
	case DB_FIRST:
	case DB_LAST:
	case DB_NEXT:
	case DB_PREV:
		break;
	case DB_SET:
		if (IS_ZERO_LSN(*alsn)) {
			__db_err(dbenv, "DB_LOGC->get: invalid LSN: %lu/%lu",
			    (u_long)alsn->file, (u_long)alsn->offset);
			return (EINVAL);
		}
		break;
	default:
		return (__db_ferr(dbenv, "DB_LOGC->get", 1));
	}

	rep_check = IS_ENV_REPLICATED(dbenv) ? 1 : 0;
	if (rep_check)
		__env_rep_enter(dbenv);
	ret = __log_c_get(logc, alsn, dbt, flags);
	if (rep_check)
		__env_db_rep_exit(dbenv);
	return (ret);
}

/*
 * __log_c_get --
 *	DB_LOGC->get.
 *
 * PUBLIC: int __log_c_get __P((DB_LOGC *, DB_LSN *, DBT *, u_int32_t));
 */
int
__log_c_get(logc, alsn, dbt, flags)
	DB_LOGC *logc;
	DB_LSN *alsn;
	DBT *dbt;
	u_int32_t flags;
{
	DB_ENV *dbenv;
	DB_LSN saved_lsn;
	int ret;

	dbenv = logc->dbenv;

	/*
	 * On error, we take care not to overwrite the caller's LSN.  This
	 * is because callers looking for the end of the log loop using the
	 * DB_NEXT flag, and expect to take the last successful lsn out of
	 * the passed-in structure after DB_LOGC->get fails with DB_NOTFOUND.
	 *
	 * !!!
	 * This line is often flagged an uninitialized memory read during a
	 * Purify or similar tool run, as the application didn't initialize
	 * *alsn.  If the application isn't setting the DB_SET flag, there is
	 * no reason it should have initialized *alsn, but we can't know that
	 * and we want to make sure we never overwrite whatever the application
	 * put in there.
	 */
	saved_lsn = *alsn;

	/*
	 * If we get one of the log's header records as a result of doing a
	 * DB_FIRST, DB_NEXT, DB_LAST or DB_PREV, repeat the operation, log
	 * file header records aren't useful to applications.
	 */
	if ((ret = __log_c_get_int(logc, alsn, dbt, flags)) != 0) {
		*alsn = saved_lsn;
		return (ret);
	}
	if (alsn->offset == 0 && (flags == DB_FIRST ||
	    flags == DB_NEXT || flags == DB_LAST || flags == DB_PREV)) {
		switch (flags) {
		case DB_FIRST:
			flags = DB_NEXT;
			break;
		case DB_LAST:
			flags = DB_PREV;
			break;
		case DB_NEXT:
		case DB_PREV:
		default:
			break;
		}
		if (F_ISSET(dbt, DB_DBT_MALLOC)) {
			__os_free(dbenv, dbt->data);
			dbt->data = NULL;
		}
		if ((ret = __log_c_get_int(logc, alsn, dbt, flags)) != 0) {
			*alsn = saved_lsn;
			return (ret);
		}
	}

	return (0);
}

/*
 * __log_c_get_int --
 *	Get a log record; internal version.
 */
static int
__log_c_get_int(logc, alsn, dbt, flags)
	DB_LOGC *logc;
	DB_LSN *alsn;
	DBT *dbt;
	u_int32_t flags;
{
	DB_CIPHER *db_cipher;
	DB_ENV *dbenv;
	DB_LOG *dblp;
	DB_LSN last_lsn, nlsn;
	HDR hdr;
	LOG *lp;
	RLOCK rlock;
	logfile_validity status;
	u_int32_t cnt;
	u_int8_t *rp;
	int eof, is_hmac, ret;

	dbenv = logc->dbenv;
	dblp = dbenv->lg_handle;
	lp = dblp->reginfo.primary;
	is_hmac = 0;

	/*
	 * We don't acquire the log region lock until we need it, and we
	 * release it as soon as we're done.
	 */
	rlock = F_ISSET(logc, DB_LOG_LOCKED) ? L_ALREADY : L_NONE;

	nlsn = logc->c_lsn;
	switch (flags) {
	case DB_NEXT:				/* Next log record. */
		if (!IS_ZERO_LSN(nlsn)) {
			/* Increment the cursor by the cursor record size. */
			nlsn.offset += logc->c_len;
			break;
		}
		flags = DB_FIRST;
		/* FALLTHROUGH */
	case DB_FIRST:				/* First log record. */
		/* Find the first log file. */
		if ((ret = __log_find(dblp, 1, &cnt, &status)) != 0)
			goto err;

		/*
		 * DB_LV_INCOMPLETE:
		 *	Theoretically, the log file we want could be created
		 *	but not yet written, the "first" log record must be
		 *	in the log buffer.
		 * DB_LV_NORMAL:
		 * DB_LV_OLD_READABLE:
		 *	We found a log file we can read.
		 * DB_LV_NONEXISTENT:
		 *	No log files exist, the "first" log record must be in
		 *	the log buffer.
		 * DB_LV_OLD_UNREADABLE:
		 *	No readable log files exist, we're at the cross-over
		 *	point between two versions.  The "first" log record
		 *	must be in the log buffer.
		 */
		switch (status) {
		case DB_LV_INCOMPLETE:
			DB_ASSERT(lp->lsn.file == cnt);
			/* FALLTHROUGH */
		case DB_LV_NORMAL:
		case DB_LV_OLD_READABLE:
			nlsn.file = cnt;
			break;
		case DB_LV_NONEXISTENT:
			nlsn.file = 1;
			DB_ASSERT(lp->lsn.file == nlsn.file);
			break;
		case DB_LV_OLD_UNREADABLE:
			nlsn.file = cnt + 1;
			DB_ASSERT(lp->lsn.file == nlsn.file);
			break;
		}
		nlsn.offset = 0;
		break;
	case DB_CURRENT:			/* Current log record. */
		break;
	case DB_PREV:				/* Previous log record. */
		if (!IS_ZERO_LSN(nlsn)) {
			/* If at start-of-file, move to the previous file. */
			if (nlsn.offset == 0) {
				if (nlsn.file == 1) {
					ret = DB_NOTFOUND;
					goto err;
				}
				if ((!lp->db_log_inmemory &&
				    (__log_valid(dblp, nlsn.file - 1, 0, NULL,
				    0, &status) != 0 ||
				    (status != DB_LV_NORMAL &&
				    status != DB_LV_OLD_READABLE)))) {
					ret = DB_NOTFOUND;
					goto err;
				}

				--nlsn.file;
			}
			nlsn.offset = logc->c_prev;
			break;
		}
		/* FALLTHROUGH */
	case DB_LAST:				/* Last log record. */
		if (rlock == L_NONE) {
			rlock = L_ACQUIRED;
			R_LOCK(dbenv, &dblp->reginfo);