Date: Sun, 22 Jul 2001 11:49:04 -0700 (PDT) From: Matt Dillon <dillon@earth.backplane.com> To: Cejka Rudolf <cejkar@dcse.fee.vutbr.cz> Cc: David Malone <dwmalone@maths.tcd.ie>, Peter Wemm <peter@wemm.org>, Terry Lambert <tlambert2@mindspring.com>, hackers@FreeBSD.ORG Subject: Re: signal(SIGCHLD, SIG_IGN) patch solving SUSv2 compatibility issue Message-ID: <200107221849.f6MIn4x10989@earth.backplane.com> References: <200106101845.f5AIje014790@earth.backplane.com> <20010611002050.362CE380E@overcee.netplex.com.au> <20010611115806.A53216@walton.maths.tcd.ie> <20010612095323.A72009@dcse.fee.vutbr.cz>
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:David Malone wrote (2001/06/11):
:> On Sun, Jun 10, 2001 at 05:20:50PM -0700, Peter Wemm wrote:
:> > I agree totally. This should have been done ages ago, I've been burned on
:> > it a few times, but never badly enough to go fix it.
:>
:> I've committed this - I'll let Matt do the MFC when he feels ready.
:
:Thanks for this commit, but it works exactly in the way, which
:I wanted to avoid. It is something like "partially submitted and
:not approved by me". Please, could you look once again on it?
:Please please please... Thanks. ;-)
Ok, sorry for the long delay, I've been playing catchup.
I've committed these additional changes to -current and I will MFC the
combined signal patch to -stable in 3 days. It looks really solid to
me. This should satisfy everyone.
-Matt
:- Hunk #1 from commit adds PS_NOCLDWAIT when SIG_IGN is used for
: SIGCHLD, so if I use
: sigemptyset(&sa.sa_mask);
: sa.sa_flags = 0;
: sa.sa_handler = SIG_IGN;
: sigaction(SIGCHLD, &sa, NULL);
: sigaction(SIGCHLD, NULL, &so);
: I get additional flag SA_NOCLDWAIT in so.sa_flags. None of tested
: systems (Solaris, Unixware, Irix, Linux, Aix) works in this way.
:- If hunk #1 is applied, I see hunk #2 (resetting SIG_IGN to SIG_DFL
: for SIGCHLD) as almost unnecessary, because it is just cosmetic
: change now and behavior in exec() is very different among various
: systems.
:- (And I have found another bug in my original patch. Three code lines
: and two bad bugs... :-( :-)
:
:Here are patches for current -current (... which I had to do in the
:first posting). These should change the behavior as is in Solaris,
:where flags are not added and SIGCHLD is resetted to SIG_DFL after an
:exec(). I'm testing these patches on my -stable production backup
:server running amanda and up to now without any problem.
:
:# Back out hunk #1 from applied commit
:
:--- sys/kern/kern_sig.c.orig Mon Jun 11 21:47:29 2001
:+++ sys/kern/kern_sig.c Tue Jun 12 07:42:42 2001
:@@ -293,8 +293,7 @@
: p->p_procsig->ps_flag |= PS_NOCLDSTOP;
: else
: p->p_procsig->ps_flag &= ~PS_NOCLDSTOP;
:- if ((act->sa_flags & SA_NOCLDWAIT) ||
:- ps->ps_sigact[_SIG_IDX(SIGCHLD)] == SIG_IGN) {
:+ if (act->sa_flags & SA_NOCLDWAIT) {
: /*
: * Paranoia: since SA_NOCLDWAIT is implemented
: * by reparenting the dying child to PID 1 (and
:
:# Add test for SIG_IGN to exit1()
:
:--- sys/kern/kern_exit.c.orig Mon Jun 11 21:47:35 2001
:+++ sys/kern/kern_exit.c Tue Jun 12 07:41:22 2001
:@@ -341,7 +341,8 @@
: * flag set, notify process 1 instead (and hope it will handle
: * this situation).
: */
:- if (p->p_pptr->p_procsig->ps_flag & PS_NOCLDWAIT) {
:+ if ((p->p_pptr->p_procsig->ps_flag & PS_NOCLDWAIT)
:+ || p->p_pptr->p_sigacts->ps_sigact[_SIG_IDX(SIGCHLD)] == SIG_IGN) {
: struct proc *pp = p->p_pptr;
: proc_reparent(p, initproc);
: /*
:
:# And this is patch for question from my first posting: ... Why? I know
:# that sa_handler and sa_sigaction are the same pointer in an union,
:# but I think that "act->sa_handler" should be exchanged with
:# "(__sighandler_t *)act->sa_sigaction" for clarification purposes.
:
:--- sys/kern/kern_sig.c Tue Jun 12 07:42:42 2001
:+++ sys/kern/kern_sig.c.new Tue Jun 12 08:16:12 2001
:@@ -259,11 +259,11 @@
: ps->ps_catchmask[_SIG_IDX(sig)] = act->sa_mask;
: SIG_CANTMASK(ps->ps_catchmask[_SIG_IDX(sig)]);
: if (act->sa_flags & SA_SIGINFO) {
:- ps->ps_sigact[_SIG_IDX(sig)] = act->sa_handler;
:- SIGADDSET(ps->ps_siginfo, sig);
:- } else {
: ps->ps_sigact[_SIG_IDX(sig)] =
: (__sighandler_t *)act->sa_sigaction;
:+ SIGADDSET(ps->ps_siginfo, sig);
:+ } else {
:+ ps->ps_sigact[_SIG_IDX(sig)] = act->sa_handler;
: SIGDELSET(ps->ps_siginfo, sig);
: }
: if (!(act->sa_flags & SA_RESTART))
:
:Thanks.
:
:--
:Rudolf Cejka (cejkar@dcse.fee.vutbr.cz; http://www.fee.vutbr.cz/~cejkar)
:Brno University of Technology, Faculty of El. Engineering and Comp. Science
:Bozetechova 2, 612 66 Brno, Czech Republic
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