Add in-kernel test runner
This adds a way to run tests inside the Smalltown kernel.
Improvements to the Bazel part of this are tracked in T726
Test Plan: Tested by intentionally failing the test.
X-Origin-Diff: phab/D485
GitOrigin-RevId: e4aad7f28d122d82a7fcb6699e678cbe022e2f73
diff --git a/core/tools/ktestinit/BUILD.bazel b/core/tools/ktestinit/BUILD.bazel
new file mode 100644
index 0000000..74eb742
--- /dev/null
+++ b/core/tools/ktestinit/BUILD.bazel
@@ -0,0 +1,16 @@
+load("@io_bazel_rules_go//go:def.bzl", "go_binary", "go_library")
+
+go_library(
+ name = "go_default_library",
+ srcs = ["main.go"],
+ importpath = "git.monogon.dev/source/nexantic.git/core/tools/ktestinit",
+ visibility = ["//visibility:private"],
+ deps = ["@org_golang_x_sys//unix:go_default_library"],
+)
+
+go_binary(
+ name = "ktestinit",
+ embed = [":go_default_library"],
+ pure = "on",
+ visibility = ["//visibility:public"],
+)
diff --git a/core/tools/ktestinit/main.go b/core/tools/ktestinit/main.go
new file mode 100644
index 0000000..9eb2342
--- /dev/null
+++ b/core/tools/ktestinit/main.go
@@ -0,0 +1,80 @@
+// 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.
+
+// ktestinit is an init designed to run inside a lightweight VM for running tests in there.
+// It performs basic platform initialization like mounting kernel filesystems and launches the
+// test executable at /tester, passes the exit code back out over the control socket to ktest and
+// then terminates the VM kernel.
+package main
+
+import (
+ "errors"
+ "fmt"
+ "os"
+ "os/exec"
+
+ "golang.org/x/sys/unix"
+)
+
+func mountInit() error {
+ for _, el := range []struct {
+ dir string
+ fs string
+ flags uintptr
+ }{
+ {"/sys", "sysfs", unix.MS_NOEXEC | unix.MS_NOSUID | unix.MS_NODEV},
+ {"/proc", "proc", unix.MS_NOEXEC | unix.MS_NOSUID | unix.MS_NODEV},
+ {"/dev", "devtmpfs", unix.MS_NOEXEC | unix.MS_NOSUID},
+ {"/dev/pts", "devpts", unix.MS_NOEXEC | unix.MS_NOSUID},
+ } {
+ if err := os.Mkdir(el.dir, 0755); err != nil && !os.IsExist(err) {
+ return fmt.Errorf("could not make %s: %w", el.dir, err)
+ }
+ if err := unix.Mount(el.fs, el.dir, el.fs, el.flags, ""); err != nil {
+ return fmt.Errorf("could not mount %s on %s: %w", el.fs, el.dir, err)
+ }
+ }
+ return nil
+}
+
+func main() {
+ if err := mountInit(); err != nil {
+ panic(err)
+ }
+
+ // First virtual serial is always stdout, second is control
+ ioConn, err := os.OpenFile("/dev/vport1p1", os.O_RDWR, 0)
+ if err != nil {
+ fmt.Printf("Failed to open communication device: %v\n", err)
+ return
+ }
+ cmd := exec.Command("/tester", "-test.v")
+ cmd.Stderr = os.Stderr
+ cmd.Stdout = os.Stdout
+ cmd.Env = append(cmd.Env, "IN_KTEST=true")
+ if err := cmd.Run(); err != nil {
+ var exerr *exec.ExitError
+ if errors.As(err, &exerr) {
+ if _, err := ioConn.Write([]byte{uint8(exerr.ExitCode())}); err != nil {
+ panic(err)
+ }
+ } else if err != nil {
+ fmt.Printf("Failed to execute tests (tests didn't run): %v", err)
+ }
+ }
+
+ unix.Reboot(unix.LINUX_REBOOT_CMD_RESTART)
+}