| As stated, no, it wouldn't work, and would be rather dangerous. It
sounds to me like taking mercury to avoid the flu. I think you're
worrying about things you shouldn't.
The reason it won't work is that you're going to have to differentiate
between the ASTs you want (like I/O completion) versus the ones you
don't want. Needless to say, this is non-trivial, and in general not
feasible. Also, if you really want to do this properly, you have to
queue yourself as a special kernel AST. Don't forget that you'll be at
IPL 2, and if you goof, the system goes down. On a time-sharing system
(you *must* be on a time-sharing system -- people on workstations don't
have this problem!), this might be interpreted as anti-social.
Anyone who can queue ASTs to your process is in kernel mode. Code in
kernel mode can do whatever it wants, given a clever enough author. If
you are being harassed by people with CMKRNL privilege, there are ways
to deal with them. The best ways involve complaining to your superiors.
Getting paranoid is a waste of time and energy. There are many niftier
hacks that are far more useful than trying to filter ASTs.
Jon
|
| This a spin off from note 525 in VMSNOTES, in 525
someone wanted to find out what terminals are getting
operator messages even tho the operator who REPLY/ENABLed
has logged out and a 'normal' user now has that device.
The programs I've seen in Vmsnotes and Hackers use the fact
that the OPR bit is set in the terminal UCB (Devclass ?) when
a reply/enable is done, but when the operator logs out
the OPR bit is clear so a scan for terminals with Opr
set will miss the terminals the author of 525 wanted.
Now the only 'person' who knows whats an operator device
is OPCOM, since it holds this data in its P1 space the only
way (I can think of) to get a true list of operator
terminals would be to send OPCOM a 'home grown' ast
requesting this info, ok thats all weel and good, fairly
staight forward but
would it be possible to send OPCOM just one ast , that causes
opcom to build a global section that maps the relevent address
of its P1 space ? so now to get a list you can use much
simpler methods than using an Ast?
Would this work ?
Ta peb
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