Re: Code in C to make a module pause?

[Jason Gerfen <jason.gerfen@xxxxxxxxxxxx>]

I think that helps a ton, thanks...

Kenneth Goodwin wrote:

> > -----Original Message-----
> > From: pam-list-bounces@xxxxxxxxxx
> > [mailto:pam-list-bounces@xxxxxxxxxx]On
> > Behalf Of Jason Gerfen
> > Sent: Friday, July 02, 2004 12:46 PM
> > To: Pluggable Authentication Modules
> > Subject: Code in C to make a module pause?
> >
> >
> > I am not sure if this is the right place to ask this
> >    
> seeing as it is
>  
>
> > more of programming question in response to how to make a
> >    
> list of
>  
>
> > system() calls pause()?
> >
> > The reason I ask is because PAM works as a shared object
> >    
> so
>  
>
> > there is no
> > interaction with the user / keyboard (after the login
> >    
> information is
>  
>
> > passed) and I would like to use the pause() function to
> >    
> require the
>  
>
> > module to wait until a system() command has finished,
> > without the need
> > to fork the process.
> >    
>
> I am presuming by system() that you are refering to the LIBC
> system() subroutine
> The system() subroutine call works by forking and execing
> the command named as it's
> string variable parameter passed as part of the call (ie
> system("/bin/who"); )
> It is a simple C library function.
>
> the fork is required in order to execute the command
> specified. The system() call itself waits
> until the command requested exits. This is in effective the
> pause() you wish.
>
> You can't Pause true system calls like open(), fork(), AND
> exec() at all.
> If I understand your question, then in the code snipnet
> below --
>
> i = 0;
> system("/bin/who");
> i++;
>
>
> "i" does not get incremented to 1 UNTIL the /bin/who command
> has completely executed and returned control
> back to the calling program. This appears to be the
> behaviour you are asking for.
> If you are doiung a FORK() call before calling System(),
> then you are probably being redunant as system() does
> not require you to fork() before calling it. It does that op
> itself.
>
> If you wish different behaviour for system(), then do a "man
> system".
> the man page has a source Code example of how to roll your
> own system() subroutine.
>
>
>
>
>
>  
>
> > Anyone accomplish this before?
> >
> > --
> > Jason Gerfen
> > Student Computing Group
> > Marriott Library
> > University of Utah
> > (801) 585-9810
> > jason.Gerfen@xxxxxxxxxxxx
> >
> > "...Sometimes I just yell at myself. And it
> >  makes me sad, sometimes I make myself cry..."
> > 			~ My nephew Dawsyn
> >
> >
> >
> > _______________________________________________
> >
> > Pam-list@xxxxxxxxxx
> > https://www.redhat.com/mailman/listinfo/pam-list
> >
> >    
>
>
> _______________________________________________
>
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>  


--
Jason Gerfen
Student Computing Group
Marriott Library
University of Utah
(801) 585-9810
jason.Gerfen@xxxxxxxxxxxx

"...Sometimes I just yell at myself. And it
makes me sad, sometimes I make myself cry..."
			~ My nephew Dawsyn



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