uprobes: Reintroduce uprobe_consumer->filter()
Finally add uprobe_consumer->filter() and change consumer_filter()
to actually call this method.
Note that ->filter() accepts mm_struct, not task_struct. Because:
1. We do not have for_each_mm_user(mm, task).
2. Even if we implement for_each_mm_user(), ->filter() can
use it itself.
3. It is not clear who will actually need this interface to
do the "nontrivial" filtering.
Another argument is "enum uprobe_filter_ctx", consumer->filter() can
use it to figure out why/where it was called. For example, perhaps
we can add UPROBE_FILTER_PRE_REGISTER used by build_map_info() to
quickly "nack" the unwanted mm's. In this case consumer should know
that it is called under ->i_mmap_mutex.
See the previous discussion at http://marc.info/?t=135214229700002
Perhaps we should pass more arguments, vma/vaddr?
Note: this patch obviously can't help to filter out the child created
by fork(), this will be addressed later.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h
index 83742b9..c2df693 100644
--- a/include/linux/uprobes.h
+++ b/include/linux/uprobes.h
@@ -35,8 +35,17 @@
# include <asm/uprobes.h>
#endif
+enum uprobe_filter_ctx {
+ UPROBE_FILTER_REGISTER,
+ UPROBE_FILTER_UNREGISTER,
+ UPROBE_FILTER_MMAP,
+};
+
struct uprobe_consumer {
int (*handler)(struct uprobe_consumer *self, struct pt_regs *regs);
+ bool (*filter)(struct uprobe_consumer *self,
+ enum uprobe_filter_ctx ctx,
+ struct mm_struct *mm);
struct uprobe_consumer *next;
};