pkg/subsystem: add the basic caller-facing interface

Users of the pkg/subsystem are only interested in
1) Fetching the list of subsystems for a given OS.
2) Matching a crash against the extracted set of subsystems.

1 files changed, 32 insertions, 0 deletions

diff --git a/pkg/subsystem/list.go b/pkg/subsystem/list.go
new file mode 100644
index 000000000..737ab859e
--- /dev/null
+++ b/pkg/subsystem/list.go
@@ -0,0 +1,32 @@
+// Copyright 2023 syzkaller project authors. All rights reserved.
+// Use of this source code is governed by Apache 2 LICENSE that can be found in the LICENSE file.
+
+package subsystem
+
+import (
+	"github.com/google/syzkaller/pkg/subsystem/entity"
+)
+
+// In general, it's not correct to assume that subsystems are only determined by target.OS,
+// because subsystems are related not to the user interface of the OS kernel, but rather to
+// the OS kernel implementation.
+//
+// For example, during fuzzing we can treat gVisor in the same way as any other Linux kernel.
+// In reality, however, not a single MAINTAINERS-based rule will work on the gVisor codebase.
+//
+// Therefore, subsystem lists have to be a completely different entity.
+
+var (
+	lists = make(map[string][]*entity.Subsystem)
+)
+
+func RegisterList(name string, list []*entity.Subsystem) {
+	if _, ok := lists[name]; ok {
+		panic(name + " subsystem list already exists!")
+	}
+	lists[name] = list
+}
+
+func GetList(name string) []*entity.Subsystem {
+	return lists[name]
+}