Reset master to testing content

internal/config/greeter.go

@@ -0,0 +1,86 @@
+// Copyright (c) 2026 Storm Dragon
+// Authors: Storm Dragon, Angus Kola
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+package config
+
+import (
+	"errors"
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+)
+
+// WriteGreeterSettings installs the effective saved profile at path. The caller
+// must run as the destination account; no privileged filesystem writes are needed.
+func WriteGreeterSettings(path string, settings Settings) error {
+	contents, err := GreeterSettings(settings)
+	if err != nil {
+		return err
+	}
+	if settings.Path != "" {
+		sourcePath, err := filepath.Abs(settings.Path)
+		if err != nil {
+			return err
+		}
+		targetPath, err := filepath.Abs(path)
+		if err != nil {
+			return err
+		}
+		source, sourceErr := os.Stat(settings.Path)
+		target, targetErr := os.Stat(path)
+		if sourcePath == targetPath || sourceErr == nil && targetErr == nil && os.SameFile(source, target) {
+			return errors.New("greeter copy cannot replace the source settings")
+		}
+	}
+	if err := os.MkdirAll(filepath.Dir(path), 0o700); err != nil {
+		return fmt.Errorf("create greeter settings directory: %w", err)
+	}
+	temporary, err := os.CreateTemp(filepath.Dir(path), ".greeter-settings-*.toml")
+	if err != nil {
+		return fmt.Errorf("create greeter settings copy: %w", err)
+	}
+	defer os.Remove(temporary.Name())
+	if _, err := temporary.Write(contents); err != nil {
+		temporary.Close()
+		return err
+	}
+	if err := temporary.Sync(); err != nil {
+		temporary.Close()
+		return err
+	}
+	if err := temporary.Close(); err != nil {
+		return err
+	}
+	if err := os.Rename(temporary.Name(), path); err != nil {
+		return fmt.Errorf("replace greeter settings copy: %w", err)
+	}
+	return syncDirectory(filepath.Dir(path))
+}
+
+// GreeterSettings encodes a complete active profile without application mappings
+// or other profiles. Tentacle registries are stored separately and are not copied.
+func GreeterSettings(settings Settings) ([]byte, error) {
+	if err := validate(settings); err != nil {
+		return nil, err
+	}
+	return encodeDocument(writableDocument{
+		SchemaVersion: CurrentSchemaVersion,
+		ActiveProfile: "greeter",
+		Profiles:      map[string]writableProfile{"greeter": profileFromSettings(settings)},
+	})
+}
+
+// ReadGreeterSettings reads the bounded snapshot from an already-open pipe.
+// Reopening /dev/stdin after switching users can fail its ownership checks.
+func ReadGreeterSettings(reader io.Reader) (Settings, error) {
+	contents, err := io.ReadAll(io.LimitReader(reader, maxConfigSize+1))
+	if err != nil {
+		return Settings{}, fmt.Errorf("read greeter settings: %w", err)
+	}
+	if len(contents) > maxConfigSize {
+		return Settings{}, fmt.Errorf("greeter settings exceed %d bytes", maxConfigSize)
+	}
+	return decodeWritable(contents)
+}