From 1b5b4c951c4f5d5495ab6acb98c586b85d123295 Mon Sep 17 00:00:00 2001 From: Sebastian Sumpf Date: Fri, 11 Jan 2013 17:14:26 +0100 Subject: [PATCH 02/15] FOC: change l4_task_cap_equal semantic The syscall l4_task_cap_equal almost returns false although the referenced kernel-objects are equal. This patch changes the semantic of the syscall so that whenever two capabilities refering the same kernel-object are compared it will return true. Please refer to the discussion of the following mail thread: http://www.mail-archive.com/l4-hackers@os.inf.tu-dresden.de/msg05162.html Was 'foc_caps_equal.patch' --- kernel/fiasco/src/kern/task.cpp | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/kernel/fiasco/src/kern/task.cpp b/kernel/fiasco/src/kern/task.cpp index 693da581..e30867e2 100644 --- a/kernel/fiasco/src/kern/task.cpp +++ b/kernel/fiasco/src/kern/task.cpp @@ -518,10 +518,15 @@ Task::sys_caps_equal(Syscall_frame *, Utcb *utcb) if (obj_a.special() || obj_b.special()) return commit_result(obj_a.special_cap() == obj_b.special_cap()); - Obj_space::Capability c_a = lookup(obj_a.cap()); - Obj_space::Capability c_b = lookup(obj_b.cap()); + Kobject_iface* ki_a = lookup(obj_a.cap()).obj(); + Kobject_iface* ki_b = lookup(obj_b.cap()).obj(); - return commit_result(c_a == c_b); + if (!ki_b || !ki_a) return commit_result(0); + + Mword o_a = ki_a->obj_id(); + Mword o_b = ki_b->obj_id(); + + return commit_result(o_a == o_b); } PRIVATE inline NOEXPORT -- 2.11.0