Re: info crashes if .infokey contains the "invalid" action

[Ken Brown]

On 3/3/2016 7:21 PM, Ken Brown wrote:
> A Cygwin user reported a crash as in the subject.  I traced it to line
> 468 of info/infokey.c, in which there is a reference to
> function_doc_array[a] with a == A_INVALID:
>
>    ke.value.function = &function_doc_array[a];
>
> As a result, ke.value.function contains garbage.  The following patch
> appears to fix the problem in very limited testing:
>
> Index: info/infokey.c
> ===================================================================
> --- info/infokey.c      (revision 7037)
> +++ info/infokey.c      (working copy)
> @@ -465,7 +465,9 @@
>                         KEYMAP_ENTRY ke;
>
>                         ke.type = ISFUNC;
> -                      ke.value.function = &function_doc_array[a];
> +                      ke.value.function = a < A_NCOMMANDS ?
> +                                &function_doc_array[a]
> +                                : NULL;
>                         To_seq (0);
>
>                         if (section == info)

This isn't the right fix.  It prevents the crash, but it doesn't 
correctly process the "invalid" line in .infokey.  I tested with the 
following .infokey:

$ cat .infokey
#info
^a invalid

After startup, ^a still moved to the beginning of the line.  I won't try 
to fix this right now, because someone familiar with the code can 
probably do it much faster.

Ken