[src/trunk]: src/sys/kern explain why the innocent sigaction1 call now works.

[christos <christos%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/b3da98718261
branches:  trunk
changeset: 326716:b3da98718261
user:      christos <christos%NetBSD.org@localhost>
date:      Fri Feb 14 16:35:40 2014 +0000

description:
explain why the innocent sigaction1 call now works.

diffstat:

 sys/kern/kern_exec.c |  14 ++++++++++++--
 1 files changed, 12 insertions(+), 2 deletions(-)

diffs (35 lines):

diff -r 6cd50cbf121f -r b3da98718261 sys/kern/kern_exec.c
--- a/sys/kern/kern_exec.c      Fri Feb 14 16:35:11 2014 +0000
+++ b/sys/kern/kern_exec.c      Fri Feb 14 16:35:40 2014 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: kern_exec.c,v 1.374 2014/02/02 14:50:46 martin Exp $   */
+/*     $NetBSD: kern_exec.c,v 1.375 2014/02/14 16:35:40 christos Exp $ */
 
 /*-
  * Copyright (c) 2008 The NetBSD Foundation, Inc.
@@ -59,7 +59,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_exec.c,v 1.374 2014/02/02 14:50:46 martin Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_exec.c,v 1.375 2014/02/14 16:35:40 christos Exp $");
 
 #include "opt_exec.h"
 #include "opt_execfmt.h"
@@ -1977,6 +1977,16 @@
                }
 
                if (spawn_data->sed_attrs->sa_flags & POSIX_SPAWN_SETSIGDEF) {
+                       /*
+                        * The following sigaction call is using a sigaction
+                        * version 0 trampoline which is in the compatibility
+                        * code only. This is not a problem because for SIG_DFL
+                        * and SIG_IGN, the trampolines are now ignored. If they
+                        * were not, this would be a problem because we are
+                        * holding the exec_lock, and the compat code needs
+                        * to do the same in order to replace the trampoline
+                        * code of the process.
+                        */
                        for (i = 1; i <= NSIG; i++) {
                                if (sigismember(
                                    &spawn_data->sed_attrs->sa_sigdefault, i))