core -> metropolis

Smalltown is now called Metropolis!

This is the first commit in a series of cleanup commits that prepare us
for an open source release. This one just some Bazel packages around to
follow a stricter directory layout.

All of Metropolis now lives in `//metropolis`.

All of Metropolis Node code now lives in `//metropolis/node`.

All of the main /init now lives in `//m/n/core`.

All of the Kubernetes functionality/glue now lives in `//m/n/kubernetes`.

Next steps:
     - hunt down all references to Smalltown and replace them appropriately
     - narrow down visibility rules
     - document new code organization
     - move `//build/toolchain` to `//monogon/build/toolchain`
     - do another cleanup pass between `//golibs` and
       `//monogon/node/{core,common}`.
     - remove `//delta` and `//anubis`

Fixes T799.

Test Plan: Just a very large refactor. CI should help us out here.

Bug: T799

X-Origin-Diff: phab/D667
GitOrigin-RevId: 6029b8d4edc42325d50042596b639e8b122d0ded
diff --git a/metropolis/node/common/sysfs/BUILD.bazel b/metropolis/node/common/sysfs/BUILD.bazel
new file mode 100644
index 0000000..a4c7f18
--- /dev/null
+++ b/metropolis/node/common/sysfs/BUILD.bazel
@@ -0,0 +1,8 @@
+load("@io_bazel_rules_go//go:def.bzl", "go_library")
+
+go_library(
+    name = "go_default_library",
+    srcs = ["uevents.go"],
+    importpath = "git.monogon.dev/source/nexantic.git/metropolis/node/common/sysfs",
+    visibility = ["//visibility:public"],
+)
diff --git a/metropolis/node/common/sysfs/uevents.go b/metropolis/node/common/sysfs/uevents.go
new file mode 100644
index 0000000..fed4319
--- /dev/null
+++ b/metropolis/node/common/sysfs/uevents.go
@@ -0,0 +1,50 @@
+// Copyright 2020 The Monogon Project Authors.
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package sysfs
+
+import (
+	"bufio"
+	"io"
+	"os"
+	"strings"
+)
+
+func ReadUevents(filename string) (map[string]string, error) {
+	f, err := os.Open(filename)
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+	ueventMap := make(map[string]string)
+	reader := bufio.NewReader(f)
+	for {
+		name, err := reader.ReadString(byte('='))
+		if err == io.EOF {
+			break
+		} else if err != nil {
+			return nil, err
+		}
+		value, err := reader.ReadString(byte('\n'))
+		if err == io.EOF {
+			continue
+		} else if err != nil {
+			return nil, err
+		}
+		ueventMap[strings.Trim(name, "=")] = strings.TrimSpace(value)
+	}
+	return ueventMap, nil
+}