Re: Do not cast void pointers to pointers requiring alignment.

[Ingo Schwarze <schwarze@usta.de>]

Hi Kristaps,

Kristaps Dzonsons wrote on Tue, Dec 20, 2011 at 11:58:07AM +0100:

> Is it easier to apply this or wait for the patch being reviewed by
> millert@?  Whichever's more convenient for you.

I guess i'll apply it unless millert@ provides feedback before
we agree on it.

> However, I don't like the assertions in this code.  A bad database
> shouldn't result in assertions (except the internal hashtable, as
> it's a programmatic matter).

I fully agree with that, but there are no assertions of the kind you
seem to suspect.

> All of these areas (index_prune(), index_read(), etc.), are built
> with failure handlers when break;ing or return badly.  Can you
> modify the patch to use these instead?

That's already the case.

Yours,
  Ingo


>>@@ -170,10 +170,10 @@ btree_read(const DBT *k, const DBT *v,
>>  	if ('\0' != ((const char *)k->data)[(int)k->size - 1])
>>  		return(0);
>>
>>-	vp = v->data;
>>  	norm_string((const char *)k->data, mc, buf);
>>-	dbv->rec = betoh32(vp->rec);
>>-	dbv->mask = betoh64(vp->mask);
>>+	memcpy(&raw_dbv, v->data, v->size);
>>+	dbv->rec = betoh32(raw_dbv.rec);
>>+	dbv->mask = betoh64(raw_dbv.mask);
>>  	return(1);
>>  }
>>

No assertion here, checks are above (unchanged).

>>@@ -369,7 +369,8 @@ index_read(const DBT *key, const DBT *va
>>  		return(0);
>>
>>  	cp = val->data;
>>-	rec->res.rec = *(recno_t *)key->data;
>>+	assert(sizeof(recno_t) == key->size);
>>+	memcpy(&rec->res.rec, key->data, key->size);
>>  	rec->res.volume = index;
>>
>>  	if ('d' == (type = *cp++))

The key is not stored in the database but is just the record number in
the file, so this asserts against internal malfunctioning of recno(3).

>>@@ -648,7 +649,9 @@ index_merge(const struct of *of, struct
>>  		seq = R_FIRST;
>>  		while (0 == (ch = (*hash->seq)(hash,&key,&val, seq))) {
>>  			seq = R_NEXT;
>>-			vbuf.mask = htobe64(*(uint64_t *)val.data);
>>+			assert(sizeof(uint64_t) == val.size);
>>+			memcpy(&mask, val.data, val.size);
>>+			vbuf.mask = htobe64(mask);
>>  			val.size = sizeof(struct db_val);
>>  			val.data =&vbuf;
>>  			dbt_put(db, dbf,&key,&val);

Assert against hash mishandling.

>>@@ -701,7 +704,8 @@ index_prune(const struct of *ofile, DB *
>>  	seq = R_FIRST;
>>  	while (0 == (ch = (*idx->seq)(idx,&key,&val, seq))) {
>>  		seq = R_NEXT;
>>-		*maxrec = *(recno_t *)key.data;
>>+		assert(sizeof(recno_t) == key.size);
>>+		memcpy(maxrec, key.data, key.size);
>>
>>  		/* Deleted records are zero-sized.  Skip them. */
>>

Assert against internal recno(3) errors, see above.

>>@@ -1073,8 +1078,11 @@ hash_put(DB *db, const struct buf *buf,
>>  	if ((rc = (*db->get)(db,&key,&val, 0))<  0) {
>>  		perror("hash");
>>  		exit((int)MANDOCLEVEL_SYSERR);
>>-	} else if (0 == rc)
>>-		mask |= *(uint64_t *)val.data;
>>+	} else if (0 == rc) {
>>+		assert(sizeof(uint64_t) == val.size);
>>+		memcpy(&oldmask, val.data, val.size);
>>+		mask |= oldmask;
>>+	}

Against hash mishandling, see above.
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