qam_files.c

这是国外的resip协议栈

			array->low_extent++;
	} else {
		if (extid == array->hi_extent)
			array->hi_extent--;
	}

err:
	MUTEX_THREAD_UNLOCK(dbenv, dbp->mutexp);
#ifdef CONFIG_TEST
	if (real_name != NULL)
		__os_free(dbenv, real_name);
#endif
	return (ret);
}

/*
 * __qam_sync --
 *	Flush the database cache.
 *
 * PUBLIC: int __qam_sync __P((DB *));
 */
int
__qam_sync(dbp)
	DB *dbp;
{
	DB_ENV *dbenv;
	DB_MPOOLFILE *mpf;

	dbenv = dbp->dbenv;
	mpf = dbp->mpf;

	/*
	 * We need to flush all extent files.  There is no easy way to find
	 * all the extents for this queue which are currently open. For now
	 * just flush the whole cache.  An alternative would be to have a
	 * call into the cache layer that would flush all of the queue extent
	 * files it has open (there's a flag when we open a queue extent file,
	 * so the cache layer can identify them).
	 */

	if (((QUEUE *)dbp->q_internal)->page_ext == 0)
		return (__memp_fsync(mpf));
	else
		return (__memp_sync(dbenv, NULL));
}

/*
 * __qam_gen_filelist -- generate a list of extent files.
 *	Another thread may close the handle so this should only
 *	be used single threaded or with care.
 *
 * PUBLIC: int __qam_gen_filelist __P(( DB *, QUEUE_FILELIST **));
 */
int
__qam_gen_filelist(dbp, filelistp)
	DB *dbp;
	QUEUE_FILELIST **filelistp;
{
	DB_ENV *dbenv;
	DB_MPOOLFILE *mpf;
	QUEUE *qp;
	QMETA *meta;
	size_t extent_cnt;
	db_recno_t i, current, first, stop, rec_extent;
	QUEUE_FILELIST *fp;
	int ret;

	dbenv = dbp->dbenv;
	mpf = dbp->mpf;
	qp = (QUEUE *)dbp->q_internal;
	*filelistp = NULL;

	if (qp->page_ext == 0)
		return (0);

	/* This may happen during metapage recovery. */
	if (qp->name == NULL)
		return (0);

	/* Find out the first and last record numbers in the database. */
	i = PGNO_BASE_MD;
	if ((ret = __memp_fget(mpf, &i, 0, &meta)) != 0)
		return (ret);

	current = meta->cur_recno;
	first = meta->first_recno;

	if ((ret = __memp_fput(mpf, meta, 0)) != 0)
		return (ret);

	/*
	 * Allocate the extent array.  Calculate the worst case number of
	 * pages and convert that to a count of extents.   The count of
	 * extents has 3 or 4 extra slots:
	 *   roundoff at first (e.g., current record in extent);
	 *   roundoff at current (e.g., first record in extent);
	 *   NULL termination; and
	 *   UINT32_MAX wraparound (the last extent can be small).
	 */
	rec_extent = qp->rec_page * qp->page_ext;
	if (current >= first)
		extent_cnt = (current - first) / rec_extent + 3;
	else
		extent_cnt =
		    (current + (UINT32_MAX - first)) / rec_extent + 4;
	if ((ret = __os_calloc(dbenv,
	    extent_cnt, sizeof(QUEUE_FILELIST), filelistp)) != 0)
		return (ret);
	fp = *filelistp;

again:
	if (current >= first)
		stop = current;
	else
		stop = UINT32_MAX;

	/*
	 * Make sure that first is at the same offset in the extent as stop.
	 * This guarantees that the stop will be reached in the loop below,
	 * even if it is the only record in its extent.  This calculation is
	 * safe because first won't move out of its extent.
	 */
	first -= first % rec_extent;
	first += stop % rec_extent;

	for (i = first; i >= first && i <= stop; i += rec_extent) {
		if ((ret = __qam_fprobe(dbp, QAM_RECNO_PAGE(dbp, i), &fp->mpf,
		    QAM_PROBE_MPF, 0)) != 0) {
			if (ret == ENOENT)
				continue;
			return (ret);
		}
		fp->id = QAM_RECNO_EXTENT(dbp, i);
		fp++;
		DB_ASSERT((size_t)(fp - *filelistp) < extent_cnt);
	}

	if (current < first) {
		first = 1;
		goto again;
	}

	return (0);
}

/*
 * __qam_extent_names -- generate a list of extent files names.
 *
 * PUBLIC: int __qam_extent_names __P((DB_ENV *, char *, char ***));
 */
int
__qam_extent_names(dbenv, name, namelistp)
	DB_ENV *dbenv;
	char *name;
	char ***namelistp;
{
	DB *dbp;
	QUEUE *qp;
	QUEUE_FILELIST *filelist, *fp;
	size_t len;
	int cnt, ret, t_ret;
	char buf[MAXPATHLEN], **cp, *freep;

	*namelistp = NULL;
	filelist = NULL;
	if ((ret = db_create(&dbp, dbenv, 0)) != 0)
		return (ret);
	if ((ret = __db_open(dbp,
	    NULL, name, NULL, DB_QUEUE, DB_RDONLY, 0, PGNO_BASE_MD)) != 0)
		return (ret);
	qp = dbp->q_internal;
	if (qp->page_ext == 0)
		goto done;

	if ((ret = __qam_gen_filelist(dbp, &filelist)) != 0)
		goto done;

	if (filelist == NULL)
		goto done;

	cnt = 0;
	for (fp = filelist; fp->mpf != NULL; fp++)
		cnt++;

	/* QUEUE_EXTENT contains extra chars, but add 6 anyway for the int. */
	len = (size_t)cnt * (sizeof(**namelistp) +
	    strlen(QUEUE_EXTENT) + strlen(qp->dir) + strlen(qp->name) + 6);

	if ((ret = __os_malloc(dbp->dbenv, len, namelistp)) != 0)
		goto done;
	cp = *namelistp;
	freep = (char *)(cp + cnt + 1);
	for (fp = filelist; fp->mpf != NULL; fp++) {
		QAM_EXNAME(qp, fp->id, buf, sizeof(buf));
		len = strlen(buf);
		*cp++ = freep;
		(void)strcpy(freep, buf);
		freep += len + 1;
	}
	*cp = NULL;

done:
	if (filelist != NULL)
		__os_free(dbp->dbenv, filelist);
	if ((t_ret = __db_close(dbp, NULL, DB_NOSYNC)) != 0 && ret == 0)
		ret = t_ret;

	return (ret);
}

/*
 * __qam_exid --
 *	Generate a fileid for an extent based on the fileid of the main
 * file.  Since we do not log schema creates/deletes explicitly, the log
 * never captures the fileid of an extent file.  In order that masters and
 * replicas have the same fileids (so they can explicitly delete them), we
 * use computed fileids for the extent files of Queue files.
 *
 * An extent file id retains the low order 12 bytes of the file id and
 * overwrites the dev/inode fields, placing a 0 in the inode field, and
 * the extent number in the dev field.
 *
 * PUBLIC: void __qam_exid __P((DB *, u_int8_t *, u_int32_t));
 */
void
__qam_exid(dbp, fidp, exnum)
	DB *dbp;
	u_int8_t *fidp;
	u_int32_t exnum;
{
	int i;
	u_int8_t *p;

	/* Copy the fileid from the master. */
	memcpy(fidp, dbp->fileid, DB_FILE_ID_LEN);

	/* The first four bytes are the inode or the FileIndexLow; 0 it. */
	for (i = sizeof(u_int32_t); i > 0; --i)
		*fidp++ = 0;

	/* The next four bytes are the dev/FileIndexHigh; insert the exnum . */
	for (p = (u_int8_t *)&exnum, i = sizeof(u_int32_t); i > 0; --i)
		*fidp++ = *p++;
}

/*
 * __qam_nameop --
 *	Remove or rename  extent files associated with a particular file.
 * This is to remove or rename (both in mpool and the file system) any
 * extent files associated with the given dbp.
 * This is either called from the QUEUE remove or rename methods or
 * when undoing a transaction that created the database.
 *
 * PUBLIC: int __qam_nameop __P((DB *, DB_TXN *, const char *, qam_name_op));
 */
int __qam_nameop(dbp, txn, newname, op)
	DB *dbp;
	DB_TXN *txn;
	const char *newname;
	qam_name_op op;
{
	DB_ENV *dbenv;
	QUEUE *qp;
	size_t exlen, fulllen, len;
	u_int8_t fid[DB_FILE_ID_LEN];
	u_int32_t exid;
	int cnt, i, ret, t_ret;
	char buf[MAXPATHLEN], nbuf[MAXPATHLEN], sepsave;
	char *endname, *endpath, *exname, *fullname, **names;
	char *ndir, *namep, *new, *cp;

	dbenv = dbp->dbenv;
	qp = (QUEUE *)dbp->q_internal;
	cnt = ret = t_ret = 0;
	namep = exname = fullname = NULL;
	names = NULL;

	/* If this isn't a queue with extents, we're done. */
	if (qp->page_ext == 0)
		return (0);

	/*
	 * Generate the list of all queue extents for this file (from the
	 * file system) and then cycle through removing them and evicting
	 * from mpool.  We have two modes of operation here.  If we are
	 * undoing log operations, then do not write log records and try
	 * to keep going even if we encounter failures in nameop.  If we
	 * are in mainline code, then return as soon as we have a problem.
	 * Memory allocation errors (__db_appname, __os_malloc) are always
	 * considered failure.
	 *
	 * Set buf to : dir/__dbq.NAME.0 and fullname to HOME/dir/__dbq.NAME.0
	 * or, in the case of an absolute path: /dir/__dbq.NAME.0
	 */
	QAM_EXNAME(qp, 0, buf, sizeof(buf));
	if ((ret =
	    __db_appname(dbenv, DB_APP_DATA, buf, 0, NULL, &fullname)) != 0)
		return (ret);

	/* We should always have a path separator here. */
	if ((endpath = __db_rpath(fullname)) == NULL) {
		ret = EINVAL;
		goto err;
	}
	sepsave = *endpath;
	*endpath = '\0';

	/*
	 * Get the list of all names in the directory and restore the
	 * path separator.
	 */
	if ((ret = __os_dirlist(dbenv, fullname, &names, &cnt)) != 0)
		goto err;
	*endpath = sepsave;

	/* If there aren't any names, don't allocate any space. */
	if (cnt == 0)
		goto err;

	/*
	 * Now, make endpath reference the queue extent names upon which
	 * we can match.  Then we set the end of the path to be the
	 * beginning of the extent number, and we can compare the bytes
	 * between endpath and endname (__dbq.NAME.).
	 */
	endpath++;
	endname = strrchr(endpath, '.');
	if (endname == NULL) {
		ret = EINVAL;
		goto err;
	}
	++endname;
	*endname = '\0';
	len = strlen(endpath);
	fulllen = strlen(fullname);

	/* Allocate space for a full extent name.  */
	exlen = fulllen + 20;
	if ((ret = __os_malloc(dbenv, exlen, &exname)) != 0)
		goto err;

	ndir = new = NULL;
	if (newname != NULL) {
		if ((ret = __os_strdup(dbenv, newname, &namep)) != 0)
			goto err;
		ndir = namep;
		if ((new = __db_rpath(namep)) != NULL)
			*new++ = '\0';
		else {
			new = namep;
			ndir = PATH_DOT;
		}
	}
	for (i = 0; i < cnt; i++) {
		/* Check if this is a queue extent file. */
		if (strncmp(names[i], endpath, len) != 0)
			continue;
		/* Make sure we have all numbers. foo.db vs. foo.db.0. */
		for (cp = &names[i][len]; *cp != '\0'; cp++)
			if (!isdigit(*cp))
				break;
		if (*cp != '\0')
			continue;

		/*
		 * We have a queue extent file.  We need to generate its
		 * name and its fileid.
		 */
		exid = (u_int32_t)strtoul(names[i] + len, NULL, 10);
		__qam_exid(dbp, fid, exid);

		switch (op) {
		case QAM_NAME_DISCARD:
			snprintf(exname, exlen,
			     "%s%s", fullname, names[i] + len);
			if ((t_ret = __memp_nameop(dbenv,
			    fid, NULL, exname, NULL)) != 0 && ret == 0)
				ret = t_ret;
			break;

		case QAM_NAME_RENAME:
			snprintf(nbuf, sizeof(nbuf), QUEUE_EXTENT,
			     ndir, PATH_SEPARATOR[0], new, exid);
			QAM_EXNAME(qp, exid, buf, sizeof(buf));
			if ((ret = __fop_rename(dbenv,
			    txn, buf, nbuf, fid, DB_APP_DATA,
			    F_ISSET(dbp, DB_AM_NOT_DURABLE) ?
			    DB_LOG_NOT_DURABLE : 0)) != 0)
				goto err;
			break;

		case QAM_NAME_REMOVE:
			QAM_EXNAME(qp, exid, buf, sizeof(buf));
			if ((ret = __fop_remove(dbenv, txn, fid, buf,
			    DB_APP_DATA, F_ISSET(dbp, DB_AM_NOT_DURABLE) ?
			    DB_LOG_NOT_DURABLE : 0)) != 0)
				goto err;
			break;
		}
	}

err:	if (fullname != NULL)
		__os_free(dbenv, fullname);
	if (exname != NULL)
		__os_free(dbenv, exname);
	if (namep != NULL)
		__os_free(dbenv, namep);
	if (names != NULL)
		__os_dirfree(dbenv, names, cnt);
	return (ret);
}