hash_verify.c

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	else
		hfunc = __ham_func5;

	if ((ret = __db_vrfy_getpageinfo(vdp, PGNO(m), &mip)) != 0)
		return (ret);

	/* Calculate the first pgno for this bucket. */
	pgno = BS_TO_PAGE(bucket, m->spares);

	if ((ret = __db_vrfy_getpageinfo(vdp, pgno, &pip)) != 0)
		goto err;

	/* Make sure we got a plausible page number. */
	if (pgno > vdp->last_pgno || pip->type != P_HASH) {
		EPRINT((dbp->dbenv,
		    "Page %lu: impossible first page in bucket %lu",
		    (u_long)pgno, (u_long)bucket));
		/* Unsafe to continue. */
		isbad = 1;
		goto err;
	}

	if (pip->prev_pgno != PGNO_INVALID) {
		EPRINT((dbp->dbenv,
		    "Page %lu: first page in hash bucket %lu has a prev_pgno",
		    (u_long)pgno, (u_long)bucket));
		isbad = 1;
	}

	/*
	 * Set flags for dups and sorted dups.
	 */
	flags |= F_ISSET(mip, VRFY_HAS_DUPS) ? ST_DUPOK : 0;
	flags |= F_ISSET(mip, VRFY_HAS_DUPSORT) ? ST_DUPSORT : 0;

	/* Loop until we find a fatal bug, or until we run out of pages. */
	for (;;) {
		/* Provide feedback on our progress to the application. */
		if (!LF_ISSET(DB_SALVAGE))
			__db_vrfy_struct_feedback(dbp, vdp);

		if ((ret = __db_vrfy_pgset_get(vdp->pgset, pgno, &p)) != 0)
			goto err;
		if (p != 0) {
			EPRINT((dbp->dbenv,
			    "Page %lu: hash page referenced twice",
			    (u_long)pgno));
			isbad = 1;
			/* Unsafe to continue. */
			goto err;
		} else if ((ret = __db_vrfy_pgset_inc(vdp->pgset, pgno)) != 0)
			goto err;

		/*
		 * Hash pages that nothing has ever hashed to may never
		 * have actually come into existence, and may appear to be
		 * entirely zeroed.  This is acceptable, and since there's
		 * no real way for us to know whether this has actually
		 * occurred, we clear the "wholly zeroed" flag on every
		 * hash page.  A wholly zeroed page, by nature, will appear
		 * to have no flags set and zero entries, so should
		 * otherwise verify correctly.
		 */
		F_CLR(pip, VRFY_IS_ALLZEROES);

		/* If we have dups, our meta page had better know about it. */
		if (F_ISSET(pip, VRFY_HAS_DUPS) &&
		    !F_ISSET(mip, VRFY_HAS_DUPS)) {
			EPRINT((dbp->dbenv,
		    "Page %lu: duplicates present in non-duplicate database",
			    (u_long)pgno));
			isbad = 1;
		}

		/*
		 * If the database has sorted dups, this page had better
		 * not have unsorted ones.
		 */
		if (F_ISSET(mip, VRFY_HAS_DUPSORT) &&
		    F_ISSET(pip, VRFY_DUPS_UNSORTED)) {
			EPRINT((dbp->dbenv,
			    "Page %lu: unsorted dups in sorted-dup database",
			    (u_long)pgno));
			isbad = 1;
		}

		/* Walk overflow chains and offpage dup trees. */
		if ((ret = __db_vrfy_childcursor(vdp, &cc)) != 0)
			goto err;
		for (ret = __db_vrfy_ccset(cc, pip->pgno, &child); ret == 0;
		    ret = __db_vrfy_ccnext(cc, &child))
			if (child->type == V_OVERFLOW) {
				if ((ret = __db_vrfy_ovfl_structure(dbp, vdp,
				    child->pgno, child->tlen, flags)) != 0) {
					if (ret == DB_VERIFY_BAD)
						isbad = 1;
					else
						goto err;
				}
			} else if (child->type == V_DUPLICATE) {
				if ((ret = __db_vrfy_duptype(dbp,
				    vdp, child->pgno, flags)) != 0) {
					isbad = 1;
					continue;
				}
				if ((ret = __bam_vrfy_subtree(dbp, vdp,
				    child->pgno, NULL, NULL,
				    flags | ST_RECNUM | ST_DUPSET | ST_TOPLEVEL,
				    NULL, NULL, NULL)) != 0) {
					if (ret == DB_VERIFY_BAD)
						isbad = 1;
					else
						goto err;
				}
			}
		if ((ret = __db_vrfy_ccclose(cc)) != 0)
			goto err;
		cc = NULL;

		/* If it's safe to check that things hash properly, do so. */
		if (isbad == 0 && !LF_ISSET(DB_NOORDERCHK) &&
		    (ret = __ham_vrfy_hashing(dbp, pip->entries,
		    m, bucket, pgno, flags, hfunc)) != 0) {
			if (ret == DB_VERIFY_BAD)
				isbad = 1;
			else
				goto err;
		}

		next_pgno = pip->next_pgno;
		ret = __db_vrfy_putpageinfo(dbp->dbenv, vdp, pip);

		pip = NULL;
		if (ret != 0)
			goto err;

		if (next_pgno == PGNO_INVALID)
			break;		/* End of the bucket. */

		/* We already checked this, but just in case... */
		if (!IS_VALID_PGNO(next_pgno)) {
			DB_ASSERT(0);
			EPRINT((dbp->dbenv,
			    "Page %lu: hash page has bad next_pgno",
			    (u_long)pgno));
			isbad = 1;
			goto err;
		}

		if ((ret = __db_vrfy_getpageinfo(vdp, next_pgno, &pip)) != 0)
			goto err;

		if (pip->prev_pgno != pgno) {
			EPRINT((dbp->dbenv,
			    "Page %lu: hash page has bad prev_pgno",
			    (u_long)next_pgno));
			isbad = 1;
		}
		pgno = next_pgno;
	}

err:	if (cc != NULL && ((t_ret = __db_vrfy_ccclose(cc)) != 0) && ret == 0)
		ret = t_ret;
	if (mip != NULL && ((t_ret =
	    __db_vrfy_putpageinfo(dbp->dbenv, vdp, mip)) != 0) && ret == 0)
		ret = t_ret;
	if (pip != NULL && ((t_ret =
	    __db_vrfy_putpageinfo(dbp->dbenv, vdp, pip)) != 0) && ret == 0)
		ret = t_ret;
	return ((ret == 0 && isbad == 1) ? DB_VERIFY_BAD : ret);
}

/*
 * __ham_vrfy_hashing --
 *	Verify that all items on a given hash page hash correctly.
 *
 * PUBLIC: int __ham_vrfy_hashing __P((DB *,
 * PUBLIC:     u_int32_t, HMETA *, u_int32_t, db_pgno_t, u_int32_t,
 * PUBLIC:     u_int32_t (*) __P((DB *, const void *, u_int32_t))));
 */
int
__ham_vrfy_hashing(dbp, nentries, m, thisbucket, pgno, flags, hfunc)
	DB *dbp;
	u_int32_t nentries;
	HMETA *m;
	u_int32_t thisbucket;
	db_pgno_t pgno;
	u_int32_t flags;
	u_int32_t (*hfunc) __P((DB *, const void *, u_int32_t));
{
	DBT dbt;
	DB_MPOOLFILE *mpf;
	PAGE *h;
	db_indx_t i;
	int ret, t_ret, isbad;
	u_int32_t hval, bucket;

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

	memset(&dbt, 0, sizeof(DBT));
	F_SET(&dbt, DB_DBT_REALLOC);

	if ((ret = mpf->get(mpf, &pgno, 0, &h)) != 0)
		return (ret);

	for (i = 0; i < nentries; i += 2) {
		/*
		 * We've already verified the page integrity and that of any
		 * overflow chains linked off it;  it is therefore safe to use
		 * __db_ret.  It's also not all that much slower, since we have
		 * to copy every hash item to deal with alignment anyway;  we
		 * can tweak this a bit if this proves to be a bottleneck,
		 * but for now, take the easy route.
		 */
		if ((ret = __db_ret(dbp, h, i, &dbt, NULL, NULL)) != 0)
			goto err;
		hval = hfunc(dbp, dbt.data, dbt.size);

		bucket = hval & m->high_mask;
		if (bucket > m->max_bucket)
			bucket = bucket & m->low_mask;

		if (bucket != thisbucket) {
			EPRINT((dbp->dbenv,
			    "Page %lu: item %lu hashes incorrectly",
			    (u_long)pgno, (u_long)i));
			isbad = 1;
		}
	}

err:	if (dbt.data != NULL)
		__os_ufree(dbp->dbenv, dbt.data);
	if ((t_ret = mpf->put(mpf, h, 0)) != 0)
		return (t_ret);

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

/*
 * __ham_salvage --
 *	Safely dump out anything that looks like a key on an alleged
 *	hash page.
 *
 * PUBLIC: int __ham_salvage __P((DB *, VRFY_DBINFO *, db_pgno_t, PAGE *,
 * PUBLIC:     void *, int (*)(void *, const void *), u_int32_t));
 */
int
__ham_salvage(dbp, vdp, pgno, h, handle, callback, flags)
	DB *dbp;
	VRFY_DBINFO *vdp;
	db_pgno_t pgno;
	PAGE *h;
	void *handle;
	int (*callback) __P((void *, const void *));
	u_int32_t flags;
{
	DBT dbt, unkdbt;
	db_pgno_t dpgno;
	int ret, err_ret, t_ret;
	u_int32_t himark, tlen;
	u_int8_t *hk;
	void *buf;
	u_int32_t dlen, len, i;

	memset(&dbt, 0, sizeof(DBT));
	dbt.flags = DB_DBT_REALLOC;

	memset(&unkdbt, 0, sizeof(DBT));
	unkdbt.size = (u_int32_t)strlen("UNKNOWN") + 1;
	unkdbt.data = "UNKNOWN";

	err_ret = 0;

	/*
	 * Allocate a buffer for overflow items.  Start at one page;
	 * __db_safe_goff will realloc as needed.
	 */
	if ((ret = __os_malloc(dbp->dbenv, dbp->pgsize, &buf)) != 0)
		return (ret);

	himark = dbp->pgsize;
	for (i = 0;; i++) {
		/* If we're not aggressive, break when we hit NUM_ENT(h). */
		if (!LF_ISSET(DB_AGGRESSIVE) && i >= NUM_ENT(h))
			break;

		/* Verify the current item. */
		ret = __db_vrfy_inpitem(dbp,
		    h, pgno, i, 0, flags, &himark, NULL);
		/* If this returned a fatality, it's time to break. */
		if (ret == DB_VERIFY_FATAL)
			break;

		if (ret == 0) {
			hk = P_ENTRY(dbp, h, i);
			len = LEN_HKEYDATA(dbp, h, dbp->pgsize, i);
			if ((u_int32_t)(hk + len - (u_int8_t *)h) >
			    dbp->pgsize) {
				/*
				 * Item is unsafely large;  either continue
				 * or set it to the whole page, depending on
				 * aggressiveness.
				 */
				if (!LF_ISSET(DB_AGGRESSIVE))
					continue;
				len = dbp->pgsize -
				    (u_int32_t)(hk - (u_int8_t *)h);
				err_ret = DB_VERIFY_BAD;
			}
			switch (HPAGE_PTYPE(hk)) {
			default:
				if (!LF_ISSET(DB_AGGRESSIVE))
					break;
				err_ret = DB_VERIFY_BAD;
				/* FALLTHROUGH */
			case H_KEYDATA:
keydata:			memcpy(buf, HKEYDATA_DATA(hk), len);
				dbt.size = len;
				dbt.data = buf;
				if ((ret = __db_prdbt(&dbt,
				    0, " ", handle, callback, 0, vdp)) != 0)
					err_ret = ret;
				break;
			case H_OFFPAGE:
				if (len < HOFFPAGE_SIZE) {
					err_ret = DB_VERIFY_BAD;
					continue;
				}
				memcpy(&dpgno,
				    HOFFPAGE_PGNO(hk), sizeof(dpgno));
				if ((ret = __db_safe_goff(dbp, vdp,
				    dpgno, &dbt, &buf, flags)) != 0) {
					err_ret = ret;
					(void)__db_prdbt(&unkdbt, 0, " ",
					    handle, callback, 0, vdp);
					break;
				}
				if ((ret = __db_prdbt(&dbt,
				    0, " ", handle, callback, 0, vdp)) != 0)
					err_ret = ret;
				break;
			case H_OFFDUP:
				if (len < HOFFPAGE_SIZE) {
					err_ret = DB_VERIFY_BAD;
					continue;
				}
				memcpy(&dpgno,
				    HOFFPAGE_PGNO(hk), sizeof(dpgno));
				/* UNKNOWN iff pgno is bad or we're a key. */
				if (!IS_VALID_PGNO(dpgno) || (i % 2 == 0)) {
					if ((ret = __db_prdbt(&unkdbt, 0, " ",
					    handle, callback, 0, vdp)) != 0)
						err_ret = ret;
				} else if ((ret = __db_salvage_duptree(dbp,
				    vdp, dpgno, &dbt, handle, callback,
				    flags | SA_SKIPFIRSTKEY)) != 0)
					err_ret = ret;
				break;
			case H_DUPLICATE:
				/*
				 * We're a key;  printing dups will seriously
				 * foul the output.  If we're being aggressive,
				 * pretend this is a key and let the app.
				 * programmer sort out the mess.
				 */
				if (i % 2 == 0) {
					err_ret = ret;
					if (LF_ISSET(DB_AGGRESSIVE))
						goto keydata;
					break;
				}

				/* Too small to have any data. */
				if (len <
				    HKEYDATA_SIZE(2 * sizeof(db_indx_t))) {
					err_ret = DB_VERIFY_BAD;
					continue;
				}

				/* Loop until we hit the total length. */
				for (tlen = 0; tlen + sizeof(db_indx_t) < len;
				    tlen += dlen) {
					tlen += sizeof(db_indx_t);
					memcpy(&dlen, hk, sizeof(db_indx_t));
					/*
					 * If dlen is too long, print all the
					 * rest of the dup set in a chunk.
					 */
					if (dlen + tlen > len)
						dlen = len - tlen;
					memcpy(buf, hk + tlen, dlen);
					dbt.size = dlen;
					dbt.data = buf;
					if ((ret = __db_prdbt(&dbt, 0, " ",
					    handle, callback, 0, vdp)) != 0)
						err_ret = ret;
					tlen += sizeof(db_indx_t);
				}
				break;
			}
		}
	}

	__os_free(dbp->dbenv, buf);
	if ((t_ret = __db_salvage_markdone(vdp, pgno)) != 0)
		return (t_ret);
	return ((ret == 0 && err_ret != 0) ? err_ret : ret);
}

/*
 * __ham_meta2pgset --
 *	Return the set of hash pages corresponding to the given
 *	known-good meta page.
 *
 * PUBLIC: int __ham_meta2pgset __P((DB *, VRFY_DBINFO *, HMETA *, u_int32_t,
 * PUBLIC:     DB *));
 */
int __ham_meta2pgset(dbp, vdp, hmeta, flags, pgset)
	DB *dbp;
	VRFY_DBINFO *vdp;
	HMETA *hmeta;
	u_int32_t flags;
	DB *pgset;
{
	DB_MPOOLFILE *mpf;
	PAGE *h;
	db_pgno_t pgno;
	u_int32_t bucket, totpgs;
	int ret, val;

	/*
	 * We don't really need flags, but leave them for consistency with
	 * __bam_meta2pgset.
	 */
	COMPQUIET(flags, 0);

	DB_ASSERT(pgset != NULL);

	mpf = dbp->mpf;
	totpgs = 0;

	/*
	 * Loop through all the buckets, pushing onto pgset the corresponding
	 * page(s) for each one.
	 */
	for (bucket = 0; bucket <= hmeta->max_bucket; bucket++) {
		pgno = BS_TO_PAGE(bucket, hmeta->spares);

		/*
		 * We know the initial pgno is safe because the spares array has
		 * been verified.
		 *
		 * Safely walk the list of pages in this bucket.
		 */
		for (;;) {
			if ((ret = mpf->get(mpf, &pgno, 0, &h)) != 0)
				return (ret);
			if (TYPE(h) == P_HASH) {

				/*
				 * Make sure we don't go past the end of
				 * pgset.
				 */
				if (++totpgs > vdp->last_pgno) {
					(void)mpf->put(mpf, h, 0);
					return (DB_VERIFY_BAD);
				}
				if ((ret =
				    __db_vrfy_pgset_inc(pgset, pgno)) != 0) {
					(void)mpf->put(mpf, h, 0);
					return (ret);
				}

				pgno = NEXT_PGNO(h);
			} else
				pgno = PGNO_INVALID;

			if ((ret = mpf->put(mpf, h, 0)) != 0)
				return (ret);

			/* If the new pgno is wonky, go onto the next bucket. */
			if (!IS_VALID_PGNO(pgno) ||
			    pgno == PGNO_INVALID)
				break;

			/*
			 * If we've touched this page before, we have a cycle;
			 * go on to the next bucket.
			 */
			if ((ret = __db_vrfy_pgset_get(pgset, pgno, &val)) != 0)
				return (ret);
			if (val != 0)
				break;
		}
	}
	return (0);
}

/*
 * __ham_dups_unsorted --
 *	Takes a known-safe hash duplicate set and its total length.
 *	Returns 1 if there are out-of-order duplicates in this set,
 *	0 if there are not.
 */
static int
__ham_dups_unsorted(dbp, buf, len)
	DB *dbp;
	u_int8_t *buf;
	u_int32_t len;
{
	DBT a, b;
	db_indx_t offset, dlen;
	int (*func) __P((DB *, const DBT *, const DBT *));

	memset(&a, 0, sizeof(DBT));
	memset(&b, 0, sizeof(DBT));

	func = (dbp->dup_compare == NULL) ? __bam_defcmp : dbp->dup_compare;

	/*
	 * Loop through the dup set until we hit the end or we find
	 * a pair of dups that's out of order.  b is always the current
	 * dup, a the one before it.
	 */
	for (offset = 0; offset < len; offset += DUP_SIZE(dlen)) {
		memcpy(&dlen, buf + offset, sizeof(db_indx_t));
		b.data = buf + offset + sizeof(db_indx_t);
		b.size = dlen;

		if (a.data != NULL && func(dbp, &a, &b) > 0)
			return (1);

		a.data = b.data;
		a.size = b.size;
	}

	return (0);
}