[src/trunk]: src/sys Add "fork hooks", a'la "exec hooks" and "exit hooks" whi...

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

details:   https://anonhg.NetBSD.org/src/rev/133c2f714dbd
branches:  trunk
changeset: 542229:133c2f714dbd
user:      thorpej <thorpej%NetBSD.org@localhost>
date:      Fri Jan 24 01:42:52 2003 +0000

description:
Add "fork hooks", a'la "exec hooks" and "exit hooks" which allow
subsystems to do special processing to the parent and/or child at
fork time.

diffstat:

 sys/kern/kern_fork.c |  10 ++++++++--
 sys/kern/kern_subr.c |  35 +++++++++++++++++++++++++++++++++--
 sys/sys/systm.h      |  10 +++++++++-
 3 files changed, 50 insertions(+), 5 deletions(-)

diffs (111 lines):

diff -r 8511e0b79fc1 -r 133c2f714dbd sys/kern/kern_fork.c
--- a/sys/kern/kern_fork.c      Fri Jan 24 01:28:05 2003 +0000
+++ b/sys/kern/kern_fork.c      Fri Jan 24 01:42:52 2003 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: kern_fork.c,v 1.105 2003/01/18 10:06:26 thorpej Exp $  */
+/*     $NetBSD: kern_fork.c,v 1.106 2003/01/24 01:42:53 thorpej Exp $  */
 
 /*-
  * Copyright (c) 1999, 2001 The NetBSD Foundation, Inc.
@@ -78,7 +78,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_fork.c,v 1.105 2003/01/18 10:06:26 thorpej Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_fork.c,v 1.106 2003/01/24 01:42:53 thorpej Exp $");
 
 #include "opt_ktrace.h"
 #include "opt_systrace.h"
@@ -376,6 +376,12 @@
                (*p2->p_emul->e_proc_fork)(p2, p1);
 
        /*
+        * ...and finally, any other random fork hooks that subsystems
+        * might have registered.
+        */
+       doforkhooks(p2, p1);
+
+       /*
         * This begins the section where we must prevent the parent
         * from being swapped.
         */
diff -r 8511e0b79fc1 -r 133c2f714dbd sys/kern/kern_subr.c
--- a/sys/kern/kern_subr.c      Fri Jan 24 01:28:05 2003 +0000
+++ b/sys/kern/kern_subr.c      Fri Jan 24 01:42:52 2003 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: kern_subr.c,v 1.95 2003/01/18 10:06:30 thorpej Exp $   */
+/*     $NetBSD: kern_subr.c,v 1.96 2003/01/24 01:42:53 thorpej Exp $   */
 
 /*-
  * Copyright (c) 1997, 1998, 1999, 2002 The NetBSD Foundation, Inc.
@@ -90,7 +90,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_subr.c,v 1.95 2003/01/18 10:06:30 thorpej Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_subr.c,v 1.96 2003/01/24 01:42:53 thorpej Exp $");
 
 #include "opt_ddb.h"
 #include "opt_md.h"
@@ -596,6 +596,37 @@
        hook_proc_run(&exithook_list, p);
 }
 
+hook_list_t forkhook_list;
+
+void *
+forkhook_establish(fn)
+       void (*fn) __P((struct proc *, struct proc *));
+{
+       return hook_establish(&forkhook_list, (void (*) __P((void *)))fn, NULL);
+}
+
+void
+forkhook_disestablish(vhook)
+       void *vhook;
+{
+       hook_disestablish(&forkhook_list, vhook);
+}
+
+/*
+ * Run fork hooks.
+ */
+void
+doforkhooks(p2, p1)
+       struct proc *p2, *p1;
+{
+       struct hook_desc *hd;
+
+       LIST_FOREACH(hd, &forkhook_list, hk_list) {
+               ((void (*) __P((struct proc *, struct proc *)))*hd->hk_fn)
+                   (p2, p1);
+       }
+}
+
 /*
  * "Power hook" types, functions, and variables.
  * The list of power hooks is kept ordered with the last registered hook
diff -r 8511e0b79fc1 -r 133c2f714dbd sys/sys/systm.h
--- a/sys/sys/systm.h   Fri Jan 24 01:28:05 2003 +0000
+++ b/sys/sys/systm.h   Fri Jan 24 01:42:52 2003 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: systm.h,v 1.156 2003/01/18 09:53:21 thorpej Exp $      */
+/*     $NetBSD: systm.h,v 1.157 2003/01/24 01:42:52 thorpej Exp $      */
 
 /*-
  * Copyright (c) 1982, 1988, 1991, 1993
@@ -330,6 +330,14 @@
 void   doexithooks __P((struct proc *));
 
 /*
+ * Fork hooks.  Subsystems may want to do special processing when a process
+ * forks.
+ */
+void   *forkhook_establish __P((void (*)(struct proc *, struct proc *)));
+void   forkhook_disestablish __P((void *));
+void   doforkhooks __P((struct proc *, struct proc *p));
+
+/*
  * kernel syscall tracing/debugging hooks.
  */
 int    trace_enter __P((struct lwp *, register_t, register_t,