treewide: introduce osbase package and move things around
All except localregistry moved from metropolis/pkg to osbase,
localregistry moved to metropolis/test as its only used there anyway.
Change-Id: If1a4bf377364bef0ac23169e1b90379c71b06d72
Reviewed-on: https://review.monogon.dev/c/monogon/+/3079
Tested-by: Jenkins CI
Reviewed-by: Serge Bazanski <serge@monogon.tech>
diff --git a/osbase/fileargs/BUILD.bazel b/osbase/fileargs/BUILD.bazel
new file mode 100644
index 0000000..e716c6f
--- /dev/null
+++ b/osbase/fileargs/BUILD.bazel
@@ -0,0 +1,9 @@
+load("@io_bazel_rules_go//go:def.bzl", "go_library")
+
+go_library(
+ name = "fileargs",
+ srcs = ["fileargs.go"],
+ importpath = "source.monogon.dev/osbase/fileargs",
+ visibility = ["//visibility:public"],
+ deps = ["@org_golang_x_sys//unix"],
+)
diff --git a/osbase/fileargs/fileargs.go b/osbase/fileargs/fileargs.go
new file mode 100644
index 0000000..7b14550
--- /dev/null
+++ b/osbase/fileargs/fileargs.go
@@ -0,0 +1,106 @@
+// 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 fileargs
+
+import (
+ "crypto/rand"
+ "encoding/hex"
+ "fmt"
+ "io"
+ "os"
+ "path/filepath"
+
+ "golang.org/x/sys/unix"
+)
+
+// DefaultSize is the default size limit for FileArgs
+const DefaultSize = 4 * 1024 * 1024
+
+// TempDirectory is the directory where FileArgs will mount the actual files
+// to. Defaults to os.TempDir() but can be globally overridden by the
+// application before any FileArgs are used.
+var TempDirectory = os.TempDir()
+
+type FileArgs struct {
+ path string
+ lastError error
+}
+
+// New initializes a new set of file-based arguments. Remember to call Close()
+// if you're done using it, otherwise this leaks memory and mounts.
+func New() (*FileArgs, error) {
+ return NewWithSize(DefaultSize)
+}
+
+// NewWithSize is the same as new, but with a custom size limit. Please be aware
+// that this data cannot be swapped out and using a size limit that's too high
+// can deadlock your kernel.
+func NewWithSize(size uint64) (*FileArgs, error) {
+ randomNameRaw := make([]byte, 128/8)
+ if _, err := io.ReadFull(rand.Reader, randomNameRaw); err != nil {
+ return nil, err
+ }
+ tmpPath := filepath.Join(TempDirectory, hex.EncodeToString(randomNameRaw))
+ if err := os.MkdirAll(tmpPath, 0700); err != nil {
+ return nil, err
+ }
+ // This uses ramfs instead of tmpfs because we never want to swap this for
+ // security reasons
+ if err := unix.Mount("none", tmpPath, "ramfs", unix.MS_NOEXEC|unix.MS_NOSUID|unix.MS_NODEV, fmt.Sprintf("size=%v", size)); err != nil {
+ return nil, err
+ }
+ return &FileArgs{
+ path: tmpPath,
+ }, nil
+}
+
+// ArgPath returns the path of the temporary file for this argument. It names
+// the temporary file according to name.
+func (f *FileArgs) ArgPath(name string, content []byte) string {
+ if f.lastError != nil {
+ return ""
+ }
+
+ path := filepath.Join(f.path, name)
+
+ if err := os.WriteFile(path, content, 0600); err != nil {
+ f.lastError = err
+ return ""
+ }
+
+ return path
+}
+
+// FileOpt returns a full option with the temporary file name already filled
+// in. Example:
+//
+// option := FileOpt("--testopt", "test.txt", []byte("hello"))
+// option == "--testopt=/tmp/daf8ed.../test.txt"
+func (f *FileArgs) FileOpt(optName, fileName string, content []byte) string {
+ return fmt.Sprintf("%v=%v", optName, f.ArgPath(fileName, content))
+}
+
+func (f *FileArgs) Error() error {
+ return f.lastError
+}
+
+func (f *FileArgs) Close() error {
+ if err := unix.Unmount(f.path, 0); err != nil {
+ return err
+ }
+ return os.Remove(f.path)
+}