Allow opening LUKS containers inside linsk ls

cmd/flags.go

@@ -0,0 +1,74 @@
+// Linsk - A utility to access Linux-native file systems on non-Linux operating systems.
+// Copyright (c) 2023 The Linsk Authors.
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+package cmd
+
+import (
+	"log/slog"
+	"os"
+
+	"github.com/spf13/pflag"
+)
+
+const defaultVMMountDevName = "vdb"
+
+func getLUKSContainerDevice() string {
+	var luksContainerDevice string
+
+	if vmRuntimeLUKSContainerFlag != "" {
+		if vmRuntimeLUKSContainerEntireDriveFlag {
+			slog.Error("--luks-container and --luks-container-entire-drive (-c) cannot be both specified at once")
+			os.Exit(1)
+		}
+
+		luksContainerDevice = vmRuntimeLUKSContainerFlag
+	} else if vmRuntimeLUKSContainerEntireDriveFlag {
+		luksContainerDevice = defaultVMMountDevName
+	}
+
+	return luksContainerDevice
+}
+
+var (
+	vmRuntimeLUKSContainerFlag            string
+	vmRuntimeLUKSContainerEntireDriveFlag bool
+
+	// These are for internal use by the initVMRuntimeFlags and configureVMRuntimeFlags functions.
+	vmRuntimeInternalAllowLUKSLowMemoryFlag bool
+
+	// These are to be initialized (set) by the initVMRuntimeFlags function.
+	vmRuntimeLUKSContainerDevice string
+)
+
+func initVMRuntimeFlags(flags *pflag.FlagSet) {
+	flags.StringVar(&vmRuntimeLUKSContainerFlag, "luks-container", "", `Specifies a device path (without "dev/" prefix) to preopen as a LUKS container (password will be prompted). Useful for accessing LVM partitions behind LUKS.`)
+	flags.BoolVarP(&vmRuntimeLUKSContainerEntireDriveFlag, "luks-container-entire-drive", "c", false, `Similar to --luks-container, but this assumes that the entire passed-through volume is a LUKS container (password will be prompted).`)
+	flags.BoolVar(&vmRuntimeInternalAllowLUKSLowMemoryFlag, "allow-luks-low-memory", false, "Allow VM memory allocation lower than 2048 MiB when LUKS is enabled.")
+}
+
+func configureVMRuntimeFlags() {
+	vmRuntimeLUKSContainerDevice = getLUKSContainerDevice()
+
+	if (luksFlag || vmRuntimeLUKSContainerDevice != "") && !vmRuntimeInternalAllowLUKSLowMemoryFlag {
+		if vmMemAllocFlag < defaultMemAllocLUKS {
+			if vmMemAllocFlag != defaultMemAlloc {
+				slog.Warn("Enforcing minimum LUKS memory allocation. Please add --allow-luks-low-memory to disable this.", "min", vmMemAllocFlag, "specified", vmMemAllocFlag)
+			}
+
+			vmMemAllocFlag = defaultMemAllocLUKS
+		}
+	}
+}