Re: [9fans] string to list?

Re: [9fans] string to list?

[presotto]

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Turning off the ability to use pipes and the environment means you
pretty much can't run any programs.  Turning of the ability to
open /dev/fd doesn't really save anything since you can always
dup.

The only ones that are really a problem are devproc and devcons.  They
are used for access to notes and to console i/o.  They were left
on since devcons protects itself, only the host owner can do anything
important, and devproc needs to be linked in anyways so that stuff
like notes works.  Access to devproc needs to be rethought.  I'm not sure the
right semantics though.

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From: Scott Schwartz <schwartz@bio.cse.psu.edu>
To: 9fans@cse.psu.edu
Subject: Re: [9fans] string to list?
Date: Sun, 10 Jun 2001 19:35:27 -0400
Message-ID: <20010610233528.26933.qmail@g.bio.cse.psu.edu>

| You can turn off access to all '#' devices except #{|decp}.  Look
| at RFNOMNT on rfork.  I believe 'rfork m' in rc does an rfork(RFNOMNT).

The manpage doesn't mention those exceptions.  Why can't you turn off
access to them too?  

Re: [9fans] string to list?

[Matt]

I'm the python guy in my office of perlies.

but at the moment the RC shell is where it's at for me

I think it would be nice if there were a plan9 specific python a like or
some sort of higher level scripting language.
The shell seems almost complete enough for now. I want to try and stick to
the 'loads of little utilities & file servers' model rather than general
purpose applications.

While I'm wishing though when I first came to plan9 of course I wanted to
bring my python hammer with me. Implementing a file server in a scripting
language sounds groovy. In the end though I'm glad it wasn't there because
it's making me learn the OS rather then live in python. Hopefully I'll
eventually know enough about it to either add the functionality to python
myself or simply not care.

M

Re: [9fans] string to list?

[Laura Creighton]

Python has a restricted eval that runs in a restricted environment.  You
can still mount a denial of service attack through that eval as far as
I know however.  Go ask in comp.lang.python where you can also get a
python tutor if you wish.

Laura
.

Re: [9fans] string to list?

[Matt]

----- Original Message ----- 
From: "Jonathan Sergent" <sergent@IO.COM>

> What's wrong with words=(`{echo $line}) and then switch($words(1))?

that is the answer I was looking for originally, thanks

Re: [9fans] string to list?

[Scott Schwartz]

| You can turn off access to all '#' devices except #{|decp}.  Look
| at RFNOMNT on rfork.  I believe 'rfork m' in rc does an rfork(RFNOMNT).

The manpage doesn't mention those exceptions.  Why can't you turn off
access to them too?  

Re: [9fans] string to list?

[presotto]

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You can turn off access to all '#' devices except #{|decp}.  Look
at RFNOMNT on rfork.  I believe 'rfork m' in rc does an rfork(RFNOMNT).

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Doesn't the availability of '#s' (i.e.  '#s'/boot) break this (unless
you are in group noworld)?

What's wrong with words=(`{echo $line}) and then switch($words(1))?


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From: "Matt" <matt@proweb.co.uk>
To: <9fans@cse.psu.edu>
Subject: Re: [9fans] string to list?
Date: Sun, 10 Jun 2001 22:48:51 +0100
Message-ID: <002501c0f1f7$235fa220$6401a8c0@freeze2k>


----- Original Message -----
From: "Scott Schwartz" <schwartz@bio.cse.psu.edu>


> | I plan to have it do eval `{$msg} and do whatever it's
> | namespace will let it.
>
> I really wouldn't do that.  It's just too unpredictable and dangerous.
> eval considered harmful.

being as I've not implemented it my understanding is weak but I thought that
I could dictate the namespace that a process sees. If the total namespace
the ircbot process sees is

/
/bin/opme
/bin/cat
/bin/ls
/bin/eval
/bin/echo
/slashdotheadlines

then all ircbot can do is  combinations like
echo eval 'ls /bin'
echo eval 'opme'
echo eval 'cat /slashdotheadlines'

but because it can't bind new files in or import them it can't manipulate
it's namespace via the eval

Re: [9fans] string to list?

[Jonathan Sergent]

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Doesn't the availability of '#s' (i.e.  '#s'/boot) break this (unless
you are in group noworld)?

What's wrong with words=(`{echo $line}) and then switch($words(1))?


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From: "Matt" <matt@proweb.co.uk>
To: <9fans@cse.psu.edu>
Subject: Re: [9fans] string to list?
Date: Sun, 10 Jun 2001 22:48:51 +0100
Message-ID: <002501c0f1f7$235fa220$6401a8c0@freeze2k>


----- Original Message -----
From: "Scott Schwartz" <schwartz@bio.cse.psu.edu>


> | I plan to have it do eval `{$msg} and do whatever it's
> | namespace will let it.
>
> I really wouldn't do that.  It's just too unpredictable and dangerous.
> eval considered harmful.

being as I've not implemented it my understanding is weak but I thought that
I could dictate the namespace that a process sees. If the total namespace
the ircbot process sees is

/
/bin/opme
/bin/cat
/bin/ls
/bin/eval
/bin/echo
/slashdotheadlines

then all ircbot can do is  combinations like
echo eval 'ls /bin'
echo eval 'opme'
echo eval 'cat /slashdotheadlines'

but because it can't bind new files in or import them it can't manipulate
it's namespace via the eval

Re: [9fans] string to list?

[Boyd Roberts]

> which you probably don't want.

s/probably/definitely/

Re: [9fans] string to list?

[Scott Schwartz]

| ...I thought that I could dictate the namespace that a process sees.

Yes, unless you someone makes a mistake.  But there's more to it
than that.  eval gives the bad guys unrestricted access to the shell,
which you probably don't want.

Re: [9fans] string to list?

[Matt]

----- Original Message -----
From: "Scott Schwartz" <schwartz@bio.cse.psu.edu>


> | I plan to have it do eval `{$msg} and do whatever it's
> | namespace will let it.
>
> I really wouldn't do that.  It's just too unpredictable and dangerous.
> eval considered harmful.

being as I've not implemented it my understanding is weak but I thought that
I could dictate the namespace that a process sees. If the total namespace
the ircbot process sees is

/
/bin/opme
/bin/cat
/bin/ls
/bin/eval
/bin/echo
/slashdotheadlines

then all ircbot can do is  combinations like
echo eval 'ls /bin'
echo eval 'opme'
echo eval 'cat /slashdotheadlines'

but because it can't bind new files in or import them it can't manipulate
it's namespace via the eval

Re: [9fans] string to list?

[Boyd Roberts]

> thanks for pushing me through the door marked awk
> a journey well worth taking

just be careful with that eval, eugene.

Re: [9fans] string to list?

[Matt]

----- Original Message ----- 
From: "Boyd Roberts" <boyd@fr.inter.net>
> > :Matt!~matt@hostname.com PRIVMSG #[s.i.s.] :some text
> > 
> > I want to turn it into
> > 
> > $nick $host $msgtype $channel $msg
> 
> eval `{echo $irctext | awk '{ ... }'}

thanks for pushing me through the door marked awk
a journey well worth taking


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Re: [9fans] string to list?

[Scott Schwartz]

| I plan to have it do eval `{$msg} and do whatever it's
| namespace will let it.

I really wouldn't do that.  It's just too unpredictable and dangerous.
eval considered harmful.

cmd=`{echo $msg}
if (fgrep -f okcmdlist $cmd(1)) {
	$cmd
} 

Re: [9fans] string to list?

[Boyd Roberts]

>  yeah that's a good idea. I didn't fancy spawning awk for every line of irc.

how about gross ifs/fn/`{...} trickery?

Re: [9fans] string to list?

[Boyd Roberts]

> They've got their monolithic perl bot running.

that's kinda funny, in a 'finally got it to run' sense.

Re: [9fans] string to list?

[vikki]

>rc irc client? sounds reasonable :)
>i wish i could find my 80-line C irc client i wrote last year for p9 (it
was
>my first project :).. come to think of it though, rc is a much better idea
>and a funnier one to implement :) wish i had a working p9 installation, i
>could've helped!

We're having a bit of a competition at work. They've got their monolithic
perl bot running. I'm trying to impress them with the plan9 version as a
learning exercise. I plan to have it do eval `{$msg} and do whatever it's
namespace will let it. They keep adding code to the perl bot and getting
deeper and deeper. Already they've had to split it in half (on my suggestion
:-) to separate information gathering and display.

>how about awk? daemonize an awk program if RC does not five you the
>utility to do it :)

 yeah that's a good idea. I didn't fancy spawning awk for every line of irc.

I did wonder one day why plan9 has any command line utilities at all apart
from bind, mount, import, unmount , cd, echo and cat.

Re: [9fans] string to list?

[andrey mirtchovski]

rc irc client? sounds reasonable :)
i wish i could find my 80-line C irc client i wrote last year for p9 (it was
my first project :).. come to think of it though, rc is a much better idea
and a funnier one to implement :) wish i had a working p9 installation, i
could've helped!

On Sun, 10 Jun 2001, Matt wrote:

> specifically I'm want to parse IRC messages with RC
> 
> given
> :Matt!~matt@hostname.com PRIVMSG #[s.i.s.] :some text
> 
> I want to turn it into
> 
> $nick $host $msgtype $channel $msg
> 
> can someone bash me with the cluestick please.
> 

how about awk? daemonize an awk program if RC does not five you the
utility to do it :) 

Re: [9fans] string to list?

[Boyd Roberts]

> :Matt!~matt@hostname.com PRIVMSG #[s.i.s.] :some text
> 
> I want to turn it into
> 
> $nick $host $msgtype $channel $msg

eval `{echo $irctext | awk '{ ... }'}

where the awk spits:

    nick='...'

etc

[9fans] string to list?

[Matt]

Hi,

list to string is documented :
list=(How now brown cow)
string=$"list

but how do I go the other way?

specifically I'm want to parse IRC messages with RC

given
:Matt!~matt@hostname.com PRIVMSG #[s.i.s.] :some text

I want to turn it into

$nick $host $msgtype $channel $msg

can someone bash me with the cluestick please.

Matt


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