Implement SA_NOCLDWAIT.
The implementation is done (unlike what i've originally been contemplating) by reparenting kids of processes that have the appropriate bit set to PID 1, and let PID 1 handle the zombie. This is far less problematical than what would seem to be ``doing it right'', for a number of reasons. Of our currently shipping PID-1-intended programs, 50 % fail the above assumption. ;-) (Read this: sysinstall doesn't do it right. This is no problem as long as no program called by sysinstall actually uses SA_NOCLDWAIT.) ToDo: . clarify the correct SA_* flag inheritance, compared to other systems, . decide whether the compat cruft (osigvec(9)) should deal with new system additions or not, . merge OpenBSD's SA_SIGINFO implementation. ;) Reviewed by: bde
This commit is contained in:
joerg
parent
1484dfe948
commit
906bfde06d
@ -36,7 +36,7 @@
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* SUCH DAMAGE.
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*
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* @(#)kern_exit.c 8.7 (Berkeley) 2/12/94
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* $Id: kern_exit.c,v 1.53 1997/08/26 00:11:55 bde Exp $
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* $Id: kern_exit.c,v 1.54 1997/09/02 20:05:38 bde Exp $
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*/
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#include "opt_ktrace.h"
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@ -294,8 +294,22 @@ exit1(p, rv)
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ruadd(p->p_ru, &p->p_stats->p_cru);
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/*
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* Notify parent that we're gone.
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* Notify parent that we're gone. If parent has the P_NOCLDWAIT
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* flag set, notify process 1 instead (and hope it will handle
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* this situation).
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*/
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if (p->p_pptr->p_flag & P_NOCLDWAIT) {
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struct proc *pp = p->p_pptr;
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proc_reparent(p, initproc);
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/*
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* If this was the last child of our parent, notify
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* parent, so in case he was wait(2)ing, he will
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* continue.
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*/
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if (LIST_EMPTY(&pp->p_children))
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wakeup((caddr_t)pp);
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}
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psignal(p->p_pptr, SIGCHLD);
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wakeup((caddr_t)p->p_pptr);
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#if defined(tahoe)
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@ -36,7 +36,7 @@
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* SUCH DAMAGE.
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*
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* @(#)kern_sig.c 8.7 (Berkeley) 4/18/94
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* $Id: kern_sig.c,v 1.32 1997/08/26 00:31:04 bde Exp $
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* $Id: kern_sig.c,v 1.33 1997/09/02 20:05:41 bde Exp $
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*/
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#include "opt_ktrace.h"
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@ -123,6 +123,8 @@ sigaction(p, uap, retval)
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sa->sa_flags |= SA_NODEFER;
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if (signum == SIGCHLD && p->p_flag & P_NOCLDSTOP)
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sa->sa_flags |= SA_NOCLDSTOP;
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if (signum == SIGCHLD && p->p_flag & P_NOCLDWAIT)
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sa->sa_flags |= SA_NOCLDWAIT;
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if ((error = copyout((caddr_t)sa, (caddr_t)uap->osa,
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sizeof (vec))))
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return (error);
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@ -182,6 +184,19 @@ setsigvec(p, signum, sa)
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p->p_flag |= P_NOCLDSTOP;
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else
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p->p_flag &= ~P_NOCLDSTOP;
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if (sa->sa_flags & SA_NOCLDWAIT) {
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/*
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* Paranoia: since SA_NOCLDWAIT is implemented by
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* reparenting the dying child to PID 1 (and
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* trust it to reap the zombie), PID 1 itself is
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* forbidden to set SA_NOCLDWAIT.
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*/
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if (p->p_pid == 1)
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p->p_flag &= ~P_NOCLDWAIT;
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else
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p->p_flag |= P_NOCLDWAIT;
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} else
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p->p_flag &= ~P_NOCLDWAIT;
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}
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/*
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* Set bit in p_sigignore for signals that are set to SIG_IGN,
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@ -36,7 +36,7 @@
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* SUCH DAMAGE.
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*
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* @(#)signal.h 8.4 (Berkeley) 5/4/95
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* $Id$
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* $Id: signal.h,v 1.11 1997/02/22 09:45:53 peter Exp $
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*/
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#ifndef _SYS_SIGNAL_H_
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@ -132,6 +132,7 @@ struct sigaction {
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#define SA_RESTART 0x0002 /* restart system call on signal return */
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#define SA_RESETHAND 0x0004 /* reset to SIG_DFL when taking signal */
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#define SA_NODEFER 0x0010 /* don't mask the signal we're delivering */
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#define SA_NOCLDWAIT 0x0020 /* don't keep zombies around */
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#ifdef COMPAT_SUNOS
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#define SA_USERTRAMP 0x0100 /* do not bounce off kernel's sigtramp */
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#endif
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@ -36,7 +36,7 @@
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* SUCH DAMAGE.
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*
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* @(#)proc.h 8.15 (Berkeley) 5/19/95
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* $Id: proc.h,v 1.41 1997/06/22 16:04:22 peter Exp $
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* $Id: proc.h,v 1.42 1997/07/06 02:40:36 dyson Exp $
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*/
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#ifndef _SYS_PROC_H_
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@ -224,6 +224,9 @@ struct proc {
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/* Marked a kernel thread */
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#define P_KTHREADP 0x200000 /* Process is really a kernel thread */
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#define P_NOCLDWAIT 0x400000 /* No zombies if child dies */
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/*
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* MOVE TO ucred.h?
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*
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@ -36,7 +36,7 @@
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* SUCH DAMAGE.
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*
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* @(#)signal.h 8.4 (Berkeley) 5/4/95
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* $Id$
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* $Id: signal.h,v 1.11 1997/02/22 09:45:53 peter Exp $
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*/
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#ifndef _SYS_SIGNAL_H_
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@ -132,6 +132,7 @@ struct sigaction {
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#define SA_RESTART 0x0002 /* restart system call on signal return */
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#define SA_RESETHAND 0x0004 /* reset to SIG_DFL when taking signal */
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#define SA_NODEFER 0x0010 /* don't mask the signal we're delivering */
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#define SA_NOCLDWAIT 0x0020 /* don't keep zombies around */
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#ifdef COMPAT_SUNOS
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#define SA_USERTRAMP 0x0100 /* do not bounce off kernel's sigtramp */
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#endif
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