Re: [PATCH] hash: silence spurious clang warning

[Eric Blake]

On 08/31/2010 08:11 AM, Eric Blake wrote:
> On 08/31/2010 02:10 AM, Jim Meyering wrote:
> > Eric, I've listed you as an author, so will wait for your ACK.
> >
> > > From 5bcff7b85b7b88fa4809ad874a1203e27abed085 Mon Sep 17 00:00:00 2001
> > From: Eric Blake<address@hidden>
> > Date: Tue, 31 Aug 2010 10:06:16 +0200
> > Subject: [PATCH] hash: factor, and guard against misbehaving hasher
> > function
> >
> > * lib/hash.c (safe_hasher): New function, to encapsulate the checking
> > of table->hasher's return value. Also protect against a hash value
> > so large that adding it to table->bucket would result in a NULL pointer.
> > (hash_lookup, hash_get_next, hash_find_entry): Use it in place of
> > open-coded check-and-abort.
>
> ACK from me.

Actually, you missed one function.  I'm squashing this in, then pushing.

> diff --git i/ChangeLog w/ChangeLog
> index ef3adf1..9ed2f79 100644
> --- i/ChangeLog
> +++ w/ChangeLog
> @@ -1,12 +1,12 @@
>  2010-08-31  Eric Blake  <address@hidden>
> -           Jim Meyering  <address@hidden>
> +       and Jim Meyering  <address@hidden>
>
>         hash: factor, and guard against misbehaving hasher function
>         * lib/hash.c (safe_hasher): New function, to encapsulate the checking
>         of table->hasher's return value.  Also protect against a hash value
>         so large that adding it to table->bucket would result in a NULL pointer.
> -       (hash_lookup, hash_get_next, hash_find_entry): Use it in place of
> -       open-coded check-and-abort.
> +       (hash_lookup, hash_get_next, hash_find_entry, transfer_entries):
> +       Use it in place of open-coded check-and-abort.
>
>  2010-08-30  Bruno Haible  <address@hidden>
>
> diff --git i/lib/hash.c w/lib/hash.c
> index 30a10b1..a4a2420 100644
> --- i/lib/hash.c
> +++ w/lib/hash.c
> @@ -877,10 +877,7 @@ transfer_entries (Hash_table *dst, Hash_table *src, bool 
> safe)
>          for (cursor = bucket->next; cursor; cursor = next)
>            {
>              data = cursor->data;
> -            new_bucket = (dst->bucket + dst->hasher (data, dst->n_buckets));
> -
> -            if (! (new_bucket < dst->bucket_limit))
> -              abort ();
> +            new_bucket = safe_hasher (dst, data);
>
>              next = cursor->next;
>
> @@ -907,10 +904,7 @@ transfer_entries (Hash_table *dst, Hash_table *src, bool 
> safe)
>          bucket->next = NULL;
>          if (safe)
>            continue;
> -        new_bucket = (dst->bucket + dst->hasher (data, dst->n_buckets));
> -
> -        if (! (new_bucket < dst->bucket_limit))
> -          abort ();
> +        new_bucket = safe_hasher (dst, data);
>
>          if (new_bucket->data)
>            {

--
Eric Blake   address@hidden    +1-801-349-2682
Libvirt virtualization library http://libvirt.org