Detecting directory changes.

[John E. Malmberg]

COLLOT Jean-Yves <Jean-Yves.COLLOT at cofiroute.fr> wrote:
> 
> (about F11X$POSIX_FASTRDSEQNOS) :
>John Malmberg wrote: 
>>I am trying to find out how stable that internal routine is.  I am 
>>trying to see if a supported interface can be developed to either give 
>>notification on change, or a way to detect changes in the directory.
> 
> As did Dave Jones (thanks again to him), I looked into the source of this
> internal VMS routine, and it looks OK to me. As I said in a previous
> message, it is not supported on VAX (VMS 7.1, which is the only version I
> have access) : it returns a "SYSYEM-E-UNSUPPORTED" status.

It is not supported on any version of OpenVMS on any platform.  It is an 
interal routine.

> I used Dave's example for testing and I am very satisfied with it, so I now
> use it very successfully for directory cache validity checking in Samba-Vms
> (for the VAX version, I keep the 30 seconds validity time-out). 

It may work for now, but as it is an internal routine, it is 
unsupported, and may break with out notice, even from the installation 
of an ECO kit.  Without knowing what is using the internal routine, I do 
not know if it will remain, will be removed, or if changes to RMS will 
leave it totally or partially non-functional.  Linking against the 
system image should also be avoided where ever possible of course.

A request from customers with a support contract for a supported API 
will have more impact on scheduling work than an internal suggestion 
from me.

Because of project deadlines, I have not had a chance to check with the 
RMS notes files to determine if there is a better supported way by using 
the lock manager, or the stability of the routine.  I do my open source 
stuff on my own computer on my own time.


There is a way that this can be done through fully supported API's on 
VAX and ALPHA, but it is a bit ugly as it requires setting security ACLs 
on the directories.  Then the SMBD program would set up an AST to 
receive the security alerts when a file gets changed.  The AST would 
have to deal with security alerts from other sources too.

I do not like this approach because an application program should not 
impose a security policy on a system.

-John
wb8tyw at qsl.net
Personal Opinion Only