[fpc-pascal] Re: Editing resource of executable

[waldo kitty]

On 8/31/2012 16:18, Mark Morgan Lloyd wrote:
> waldo kitty wrote:
>
>> i also used this technique to store registration data and options settings
>> directly in the executable instead of having a separate and external
>> configuration file...
>>
>> i can post those old sources if anyone is interested... they only need ask...
>> the sources are dated May 1993 and i likely saved them from the Fidonet PASCAL
>> echo (message area)... they might have even ended up in the SWAG archives but
>> i don't know ;) -=B-)
>
> I did this sort of thing back in the days of MZ files, where there was a simple
> length field in the header.

and that's one of the thing this main routine uses to jump to the end real 
quickly... but there's also a set of starting and ending markers... plus the 
fact that the data is a "Typed Constant" is another factor... i don't recall for 
sure, but i think i've been told that FPC doesn't have typed constants???

> I believe that NE files similarly had an accessible overall length, but they
> also had a checksum field even though this was rarely (if ever) used.

interesting... this routine has a checksum item built into it... IIRC, it was so 
we could detect if the executable had been modified and abort operation if true...

> Later Windows formats (PE etc.) might use signing/blessing/branding/checksumming
> to varying extents, and I also think there was discussion of unix-style signing
> in this (or a related) list a few weeks ago.
>
> Which leaves me thinking that the safest way of doing it would be to look for an
> "official" program, i.e. from MS or from unix binutils, which- if a program was
> already signed- might request some sort of key before it would change anything.
>
> Of course, an even safer way would be to leave the executable alone and to put
> an early check in the startup code that a subsidiary key file existed, and for
> that key to include something that identified the machine or site on which the
> program was entitled to run.

true... but as i recall, one of the goals of this capability was to not have 
extra files laying about... i remember the days of dongles and never liked them 
at all...