db_vrfy.c

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		else {
			isbad = 1;
			EPRINT((dbenv,
			    "Page %lu: bad magic number %lu",
			    (u_long)PGNO_BASE_MD, (u_long)meta->magic));
		}
	}

	/*
	 * 16-19: Version.  Must be current;  for now, we
	 * don't support verification of old versions.
	 */
	if (swapped)
		M_32_SWAP(meta->version);
	if ((dbp->type == DB_BTREE &&
	    (meta->version > DB_BTREEVERSION ||
	    meta->version < DB_BTREEOLDVER)) ||
	    (dbp->type == DB_HASH &&
	    (meta->version > DB_HASHVERSION ||
	    meta->version < DB_HASHOLDVER)) ||
	    (dbp->type == DB_QUEUE &&
	    (meta->version > DB_QAMVERSION ||
	    meta->version < DB_QAMOLDVER))) {
		isbad = 1;
		EPRINT((dbenv,
    "Page %lu: unsupported DB version %lu; extraneous errors may result",
		    (u_long)PGNO_BASE_MD, (u_long)meta->version));
	}

	/*
	 * 20-23: Pagesize.  Must be power of two,
	 * greater than 512, and less than 64K.
	 */
	if (swapped)
		M_32_SWAP(meta->pagesize);
	if (IS_VALID_PAGESIZE(meta->pagesize))
		dbp->pgsize = meta->pagesize;
	else {
		isbad = 1;
		EPRINT((dbenv, "Page %lu: bad page size %lu",
		    (u_long)PGNO_BASE_MD, (u_long)meta->pagesize));

		/*
		 * Now try to settle on a pagesize to use.
		 * If the user-supplied one is reasonable,
		 * use it;  else, guess.
		 */
		if (!IS_VALID_PAGESIZE(dbp->pgsize))
			dbp->pgsize = __db_guesspgsize(dbenv, fhp);
	}

	/*
	 * 25: Page type.  Must be correct for dbp->type,
	 * which is by now set as well as it can be.
	 */
	/* Needs no swapping--only one byte! */
	if ((dbp->type == DB_BTREE && meta->type != P_BTREEMETA) ||
	    (dbp->type == DB_HASH && meta->type != P_HASHMETA) ||
	    (dbp->type == DB_QUEUE && meta->type != P_QAMMETA)) {
		isbad = 1;
		EPRINT((dbenv, "Page %lu: bad page type %lu",
		    (u_long)PGNO_BASE_MD, (u_long)meta->type));
	}

	/*
	 * 28-31: Free list page number.
	 * We'll verify its sensibility when we do inter-page
	 * verification later;  for now, just store it.
	 */
	if (swapped)
	    M_32_SWAP(meta->free);
	freelist = meta->free;

	/*
	 * Initialize vdp->pages to fit a single pageinfo structure for
	 * this one page.  We'll realloc later when we know how many
	 * pages there are.
	 */
	if ((ret = __db_vrfy_getpageinfo(vdp, PGNO_BASE_MD, &pip)) != 0)
		return (ret);
	pip->pgno = PGNO_BASE_MD;
	pip->type = meta->type;

	/*
	 * Signal that we still have to check the info specific to
	 * a given type of meta page.
	 */
	F_SET(pip, VRFY_INCOMPLETE);

	pip->free = freelist;

	if ((ret = __db_vrfy_putpageinfo(dbenv, vdp, pip)) != 0)
		return (ret);

	/* Set up the dbp's fileid.  We don't use the regular open path. */
	memcpy(dbp->fileid, meta->uid, DB_FILE_ID_LEN);

	if (swapped == 1)
		F_SET(dbp, DB_AM_SWAP);

	return (isbad ? DB_VERIFY_BAD : 0);
}

/*
 * __db_vrfy_walkpages --
 *	Main loop of the verifier/salvager.  Walks through,
 *	page by page, and verifies all pages and/or prints all data pages.
 */
static int
__db_vrfy_walkpages(dbp, vdp, handle, callback, flags)
	DB *dbp;
	VRFY_DBINFO *vdp;
	void *handle;
	int (*callback) __P((void *, const void *));
	u_int32_t flags;
{
	DB_ENV *dbenv;
	DB_MPOOLFILE *mpf;
	PAGE *h;
	db_pgno_t i;
	int ret, t_ret, isbad;

	dbenv = dbp->dbenv;
	mpf = dbp->mpf;
	ret = isbad = t_ret = 0;

	if ((ret = __db_fchk(dbenv,
	    "__db_vrfy_walkpages", flags, OKFLAGS)) != 0)
		return (ret);

	for (i = 0; i <= vdp->last_pgno; i++) {
		/*
		 * If DB_SALVAGE is set, we inspect our database of
		 * completed pages, and skip any we've already printed in
		 * the subdb pass.
		 */
		if (LF_ISSET(DB_SALVAGE) && (__db_salvage_isdone(vdp, i) != 0))
			continue;

		/*
		 * If an individual page get fails, keep going if and only
		 * if we're salvaging.
		 */
		if ((t_ret = mpf->get(mpf, &i, 0, &h)) != 0) {
			if (ret == 0)
				ret = t_ret;
			if (LF_ISSET(DB_SALVAGE))
				continue;
			else
				return (ret);
		}

		if (LF_ISSET(DB_SALVAGE)) {
			/*
			 * We pretty much don't want to quit unless a
			 * bomb hits.  May as well return that something
			 * was screwy, however.
			 */
			if ((t_ret = __db_salvage(dbp,
			    vdp, i, h, handle, callback, flags)) != 0) {
				if (ret == 0)
					ret = t_ret;
				isbad = 1;
			}
		} else {
			/*
			 * If we are not salvaging, and we get any error
			 * other than DB_VERIFY_BAD, return immediately;
			 * it may not be safe to proceed.  If we get
			 * DB_VERIFY_BAD, keep going;  listing more errors
			 * may make it easier to diagnose problems and
			 * determine the magnitude of the corruption.
			 */

			/*
			 * Verify info common to all page
			 * types.
			 */
			if (i != PGNO_BASE_MD) {
				ret = __db_vrfy_common(dbp, vdp, h, i, flags);
				if (ret == DB_VERIFY_BAD)
					isbad = 1;
				else if (ret != 0)
					goto err;
			}

			switch (TYPE(h)) {
			case P_INVALID:
				ret = __db_vrfy_invalid(dbp, vdp, h, i, flags);
				break;
			case __P_DUPLICATE:
				isbad = 1;
				EPRINT((dbenv,
				    "Page %lu: old-style duplicate page",
				    (u_long)i));
				break;
			case P_HASH:
				ret = __ham_vrfy(dbp,
				    vdp, h, i, flags);
				break;
			case P_IBTREE:
			case P_IRECNO:
			case P_LBTREE:
			case P_LDUP:
				ret = __bam_vrfy(dbp,
				    vdp, h, i, flags);
				break;
			case P_LRECNO:
				ret = __ram_vrfy_leaf(dbp,
				    vdp, h, i, flags);
				break;
			case P_OVERFLOW:
				ret = __db_vrfy_overflow(dbp,
				    vdp, h, i, flags);
				break;
			case P_HASHMETA:
				ret = __ham_vrfy_meta(dbp,
				    vdp, (HMETA *)h, i, flags);
				break;
			case P_BTREEMETA:
				ret = __bam_vrfy_meta(dbp,
				    vdp, (BTMETA *)h, i, flags);
				break;
			case P_QAMMETA:
				ret = __qam_vrfy_meta(dbp,
				    vdp, (QMETA *)h, i, flags);
				break;
			case P_QAMDATA:
				ret = __qam_vrfy_data(dbp,
				    vdp, (QPAGE *)h, i, flags);
				break;
			default:
				EPRINT((dbenv,
				    "Page %lu: unknown page type %lu",
				    (u_long)i, (u_long)TYPE(h)));
				isbad = 1;
				break;
			}

			/*
			 * Set up error return.
			 */
			if (ret == DB_VERIFY_BAD)
				isbad = 1;
			else if (ret != 0)
				goto err;

			/*
			 * Provide feedback to the application about our
			 * progress.  The range 0-50% comes from the fact
			 * that this is the first of two passes through the
			 * database (front-to-back, then top-to-bottom).
			 */
			if (dbp->db_feedback != NULL)
				dbp->db_feedback(dbp, DB_VERIFY,
				    (i + 1) * 50 / (vdp->last_pgno + 1));
		}

		/*
		 * Just as with the page get, bail if and only if we're
		 * not salvaging.
		 */
		if ((t_ret = mpf->put(mpf, h, 0)) != 0) {
			if (ret == 0)
				ret = t_ret;
			if (!LF_ISSET(DB_SALVAGE))
				return (ret);
		}
	}

	if (0) {
err:		if ((t_ret = mpf->put(mpf, h, 0)) != 0)
			return (ret == 0 ? t_ret : ret);
	}

	return ((isbad == 1 && ret == 0) ? DB_VERIFY_BAD : ret);
}

/*
 * __db_vrfy_structure--
 *	After a beginning-to-end walk through the database has been
 *	completed, put together the information that has been collected
 *	to verify the overall database structure.
 *
 *	Should only be called if we want to do a database verification,
 *	i.e. if DB_SALVAGE is not set.
 */
static int
__db_vrfy_structure(dbp, vdp, dbname, meta_pgno, flags)
	DB *dbp;
	VRFY_DBINFO *vdp;
	const char *dbname;
	db_pgno_t meta_pgno;
	u_int32_t flags;
{
	DB *pgset;
	DB_ENV *dbenv;
	VRFY_PAGEINFO *pip;
	db_pgno_t i;
	int ret, isbad, hassubs, p;

	isbad = 0;
	pip = NULL;
	dbenv = dbp->dbenv;
	pgset = vdp->pgset;

	if ((ret = __db_fchk(dbenv, "DB->verify", flags, OKFLAGS)) != 0)
		return (ret);
	if (LF_ISSET(DB_SALVAGE)) {
		__db_err(dbenv, "__db_vrfy_structure called with DB_SALVAGE");
		return (EINVAL);
	}

	/*
	 * Providing feedback here is tricky;  in most situations,
	 * we fetch each page one more time, but we do so in a top-down
	 * order that depends on the access method.  Worse, we do this
	 * recursively in btree, such that on any call where we're traversing
	 * a subtree we don't know where that subtree is in the whole database;
	 * worse still, any given database may be one of several subdbs.
	 *
	 * The solution is to decrement a counter vdp->pgs_remaining each time
	 * we verify (and call feedback on) a page.  We may over- or
	 * under-count, but the structure feedback function will ensure that we
	 * never give a percentage under 50 or over 100.  (The first pass
	 * covered the range 0-50%.)
	 */
	if (dbp->db_feedback != NULL)
		vdp->pgs_remaining = vdp->last_pgno + 1;

	/*
	 * Call the appropriate function to downwards-traverse the db type.
	 */
	switch(dbp->type) {
	case DB_BTREE:
	case DB_RECNO:
		if ((ret = __bam_vrfy_structure(dbp, vdp, 0, flags)) != 0) {
			if (ret == DB_VERIFY_BAD)
				isbad = 1;
			else
				goto err;
		}

		/*
		 * If we have subdatabases and we know that the database is,
		 * thus far, sound, it's safe to walk the tree of subdatabases.
		 * Do so, and verify the structure of the databases within.
		 */
		if ((ret = __db_vrfy_getpageinfo(vdp, 0, &pip)) != 0)
			goto err;
		hassubs = F_ISSET(pip, VRFY_HAS_SUBDBS) ? 1 : 0;
		if ((ret = __db_vrfy_putpageinfo(dbenv, vdp, pip)) != 0)
			goto err;

		if (isbad == 0 && hassubs)
			if ((ret =
			    __db_vrfy_subdbs(dbp, vdp, dbname, flags)) != 0) {
				if (ret == DB_VERIFY_BAD)
					isbad = 1;
				else
					goto err;
			}
		break;
	case DB_HASH:
		if ((ret = __ham_vrfy_structure(dbp, vdp, 0, flags)) != 0) {
			if (ret == DB_VERIFY_BAD)
				isbad = 1;
			else
				goto err;
		}
		break;
	case DB_QUEUE:
		if ((ret = __qam_vrfy_structure(dbp, vdp, flags)) != 0) {
			if (ret == DB_VERIFY_BAD)
				isbad = 1;
		}

		/*
		 * Queue pages may be unreferenced and totally zeroed, if
		 * they're empty;  queue doesn't have much structure, so
		 * this is unlikely to be wrong in any troublesome sense.
		 * Skip to "err".
		 */
		goto err;
		/* NOTREACHED */
	default:
		/* This should only happen if the verifier is somehow broken. */
		DB_ASSERT(0);
		ret = EINVAL;
		goto err;
		/* NOTREACHED */
	}

	/* Walk free list. */
	if ((ret =
	    __db_vrfy_freelist(dbp, vdp, meta_pgno, flags)) == DB_VERIFY_BAD)
		isbad = 1;

	/*
	 * If structure checks up until now have failed, it's likely that
	 * checking what pages have been missed will result in oodles of
	 * extraneous error messages being EPRINTed.  Skip to the end
	 * if this is the case;  we're going to be printing at least one
	 * error anyway, and probably all the more salient ones.
	 */
	if (ret != 0 || isbad == 1)
		goto err;

	/*
	 * Make sure no page has been missed and that no page is still marked
	 * "all zeroes" (only certain hash pages can be, and they're unmarked
	 * in __ham_vrfy_structure).
	 */
	for (i = 0; i < vdp->last_pgno + 1; i++) {
		if ((ret = __db_vrfy_getpageinfo(vdp, i, &pip)) != 0)
			goto err;
		if ((ret = __db_vrfy_pgset_get(pgset, i, &p)) != 0)
			goto err;
		if (p == 0) {
			EPRINT((dbenv,
			    "Page %lu: unreferenced page", (u_long)i));
			isbad = 1;
		}

		if (F_ISSET(pip, VRFY_IS_ALLZEROES)) {
			EPRINT((dbenv,
			    "Page %lu: totally zeroed page", (u_long)i));
			isbad = 1;
		}
		if ((ret = __db_vrfy_putpageinfo(dbenv, vdp, pip)) != 0)
			goto err;
		pip = NULL;
	}

err:	if (pip != NULL)
		(void)__db_vrfy_putpageinfo(dbenv, vdp, pip);

	return ((isbad == 1 && ret == 0) ? DB_VERIFY_BAD : ret);
}

/*
 * __db_is_valid_pagetype
 */
static int
__db_is_valid_pagetype(type)
	u_int32_t type;
{
	switch (type) {
	case P_INVALID:			/* Order matches ordinal value. */
	case P_HASH:
	case P_IBTREE:
	case P_IRECNO:
	case P_LBTREE:
	case P_LRECNO:
	case P_OVERFLOW:
	case P_HASHMETA:
	case P_BTREEMETA:
	case P_QAMMETA:
	case P_QAMDATA:
	case P_LDUP:
		return (1);
	}
	return (0);
}

/*
 * __db_is_valid_magicno
 */
static int
__db_is_valid_magicno(magic, typep)
	u_int32_t magic;
	DBTYPE *typep;
{
	switch (magic) {
	case DB_BTREEMAGIC:
		*typep = DB_BTREE;
		return (1);
	case DB_HASHMAGIC:
		*typep = DB_HASH;
		return (1);
	case DB_QAMMAGIC:
		*typep = DB_QUEUE;
		return (1);
	}
	*typep = DB_UNKNOWN;
	return (0);
}

/*
 * __db_vrfy_common --
 *	Verify info common to all page types.
 */
static int