From: dashw459@aol.comeatspam
Sent: Monday, August 14, 2000 8:40 PM
To: Info-VAX@Mvb.Saic.Com
Subject: Re: STOP/ID

<< If you can, you could try to modify this application to set the nodelete
bit on the process.  >>

The cure may be worse than the disease...


/****************************************************************/

/*								*/

/* 			   S   T   P				*/

/*								*/

/* A new high in XXX design.  Ingestion makes everything lucid. */

/* XXX employs user mode spin locks to serialize access to	*/

/* shared resources.  Unanticipated process termination		*/

/* (user ctrl-Y, DCL STOP, EXEC delprc, may leave a resource	*/

/* permanently locked.	These routines attempt to provide part 	*/

/* of a solution by enabling the user to make his process	*/

/* nondeletable.  This works for STOP, SYS$EXIT, SYS$FORCEX and	*/

/* SYS$DELPRC.  It does not work for CTRL-Y or C.  Out of band	*/

/* AST catchers will be required!				*/

/* 								*/

/* WARNING:							*/

/* Privileged kernel mode software.  These routines can have	*/

/* terrible side affects.  Users may find themselves with	*/

/* processes that can not be deleted, making reboot necessary.	*/

/* Aborting an interactive process set no delete can cause	*/

/* loginout to execute forever consuming huge amnounts of CPU.	*/

/* 								*/

/* WARNING:							*/

/* PCB is not locked when modified.  If this becomes a problem	*/

/* will have to take out a lock.				*/

/*								*/

/* WARNING:							*/

/* USE EXTREME CAUTION!  Only use these routines if there	*/

/* are no alternatives.						*/

/*								*/

/* Creation Date: 04/15/97					*/

/*								*/

/* Revision History:						*/

/*								*/

/****************************************************************/



/*

$cc/list stp+alpha$library:sys$lib_c.tlb/libr

$link/sysexe 'your program obj',stp

*/



#include <pcbdef.h>	/* YIPPEE TY OH I AYYYE */

#include <starlet.h>

#include <ssdef.h>









/****************************************************************/

/*								*/

/*		     u n s t o p p a b l e			*/

/*								*/

/* Private kernel mode routine called by f_stp_unstoppable()	*/

/* Turn on (WHEE!) callers NO DELETE PCB status bit.		*/

/****************************************************************/

static int unstoppable()

{

  /* turn PCB status bit for no delete on  (set bit) */

#pragma nostandard

  globalref ctl$gl_pcb;

#pragma standard

  PCB *p = (PCB *) ctl$gl_pcb;



  p->pcb$l_sts |= PCB$M_NODELET;

  return(SS$_NORMAL);

}









/****************************************************************/

/*								*/

/*		     s t o p p a b l e 				*/

/*								*/

/* Private kernel mode routine called by f_stp_stoppable()	*/

/* Turn off (BOO HISS) callers NO DELETE PCB status bit.	*/

/*								*/

/****************************************************************/

static int stoppable()

{

  /* turn PCB status bit for no delete off (clear bit) */

#pragma nostandard

  globalref ctl$gl_pcb;

#pragma standard

  PCB *p = (PCB *) ctl$gl_pcb;



  p->pcb$l_sts &= ~PCB$M_NODELET;

  return(SS$_NORMAL);

}







/****************************************************************/

/*								*/

/*	      f _ s t p _ u n s t o p p a b l e			*/

/*								*/

/* Public routine to make callers process non deletable.	*/

/* Returns: system status, SS$_NORMAL or SS$_NOPRIV		*/

/*								*/

/****************************************************************/

int f_stp_unstoppable()

{

  return( sys$cmkrnl( unstoppable, 0));

}







/****************************************************************/

/*								*/

/*	         f _ s t p _ s t o p p a b l e			*/

/*								*/

/* Public routine to make callers process non deletable.	*/

/* Returns: system status, SS$_NORMAL or SS$_NOPRIV		*/

/*								*/

/****************************************************************/

int f_stp_stoppable()

{

  return( sys$cmkrnl( stoppable, 0));

}