[PATCH] lib/tdb: fix append of zero-length records to zero-length records.

[Jeremy Allison]

On Thu, Jul 30, 2009 at 01:45:41PM +0930, Rusty Russell wrote:
> realloc() has that horrible overloaded free semantic when size is 0:
> current code does a free of the old record in this case, then fail.
> 
> Signed-off-by: Rusty Russell <rusty at rustcorp.com.au>
> ---
>  lib/tdb/common/tdb.c |    9 +++++++--
>  1 files changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/lib/tdb/common/tdb.c b/lib/tdb/common/tdb.c
> index b59bb15..b78f74c 100644
> --- a/lib/tdb/common/tdb.c
> +++ b/lib/tdb/common/tdb.c
> @@ -584,8 +584,13 @@ int tdb_append(struct tdb_context *tdb, TDB_DATA key, TDB_DATA new_dbuf)
>  	if (dbuf.dptr == NULL) {
>  		dbuf.dptr = (unsigned char *)malloc(new_dbuf.dsize);
>  	} else {
> -		unsigned char *new_dptr = (unsigned char *)realloc(dbuf.dptr,
> -						     dbuf.dsize + new_dbuf.dsize);
> +		unsigned int new_len = dbuf.dsize + new_dbuf.dsize;
> +		unsigned char *new_dptr;
> +
> +		/* realloc '0' is special: don't do that. */
> +		if (new_len == 0)
> +			new_len = 1;
> +		new_dptr = (unsigned char *)realloc(dbuf.dptr, new_len);
>  		if (new_dptr == NULL) {
>  			free(dbuf.dptr);
>  		}

Pushed both of these fixes - thanks Rusty !

Jeremy.