Archive Mount as Filesystem (FUSE)

cmd/mount.go

@@ -0,0 +1,97 @@
+package cmd
+
+import (
+	"fmt"
+	"os"
+	"os/signal"
+	"strings"
+	"syscall"
+
+	"github.com/Snider/Borg/pkg/datanode"
+	"github.com/Snider/Borg/pkg/fusefs"
+	"github.com/Snider/Borg/pkg/tim"
+	"github.com/Snider/Borg/pkg/trix"
+	"github.com/hanwen/go-fuse/v2/fs"
+	"github.com/hanwen/go-fuse/v2/fuse"
+	"github.com/spf13/cobra"
+)
+
+var mountCmd = NewMountCmd()
+
+func NewMountCmd() *cobra.Command {
+	cmd := &cobra.Command{
+		Use:   "mount [archive] [mountpoint]",
+		Short: "Mount an archive as a read-only filesystem",
+		Args:  cobra.ExactArgs(2),
+		RunE: func(cmd *cobra.Command, args []string) error {
+			archiveFile := args[0]
+			mountpoint := args[1]
+			password, _ := cmd.Flags().GetString("password")
+
+			data, err := os.ReadFile(archiveFile)
+			if err != nil {
+				return err
+			}
+
+			var dn *datanode.DataNode
+			if strings.HasSuffix(archiveFile, ".stim") || (len(data) >= 4 && string(data[:4]) == "STIM") {
+				if password == "" {
+					return fmt.Errorf("password required for .stim files")
+				}
+				m, err := tim.FromSigil(data, password)
+				if err != nil {
+					return err
+				}
+				tarball, err := m.ToTar()
+				if err != nil {
+					return err
+				}
+				dn, err = datanode.FromTar(tarball)
+				if err != nil {
+					return err
+				}
+			} else {
+				// This handles .dat, .tar, .trix, and .tim files
+				dn, err = trix.FromTrix(data, password)
+				if err != nil {
+					// If FromTrix fails, try FromTar as a fallback for plain tarballs
+					if dn, err = datanode.FromTar(data); err != nil {
+						return err
+					}
+				}
+			}
+
+			root := fusefs.NewDataNodeFs(dn)
+			server, err := fs.Mount(mountpoint, root, &fs.Options{
+				MountOptions: fuse.MountOptions{
+					Debug: true,
+				},
+			})
+			if err != nil {
+				return err
+			}
+
+			c := make(chan os.Signal, 1)
+			signal.Notify(c, os.Interrupt, syscall.SIGTERM)
+			go func() {
+				<-c
+				server.Unmount()
+			}()
+
+			fmt.Fprintf(cmd.OutOrStdout(), "Archive mounted at %s. Press Ctrl+C to unmount.\n", mountpoint)
+			server.Wait()
+
+			return nil
+		},
+	}
+	cmd.Flags().StringP("password", "p", "", "Password for encrypted archives")
+	return cmd
+}
+
+func GetMountCmd() *cobra.Command {
+	return mountCmd
+}
+
+func init() {
+	RootCmd.AddCommand(GetMountCmd())
+}

cmd/mount_test.go

@@ -0,0 +1,108 @@
+package cmd
+
+import (
+	"context"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"runtime"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/Snider/Borg/pkg/datanode"
+	"github.com/hanwen/go-fuse/v2/fuse"
+)
+
+func TestMountCommand(t *testing.T) {
+	if runtime.GOOS != "linux" {
+		t.Skip("skipping mount test on non-linux systems")
+	}
+	if _, err := exec.LookPath("fusermount"); err != nil {
+		t.Skip("fusermount not found, skipping mount test")
+	}
+
+	// Create a temporary directory for the mount point
+	mountDir := t.TempDir()
+
+	// Create a dummy archive
+	dn := datanode.New()
+	dn.AddData("test.txt", []byte("hello"))
+	tarball, err := dn.ToTar()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	archiveFile := filepath.Join(t.TempDir(), "test.dat")
+	if err := os.WriteFile(archiveFile, tarball, 0644); err != nil {
+		t.Fatal(err)
+	}
+
+	// Run the mount command in the background
+	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+	defer cancel()
+
+	cmd := NewMountCmd()
+	cmd.SetArgs([]string{archiveFile, mountDir})
+
+	cmdErrCh := make(chan error, 1)
+	go func() {
+		cmdErrCh <- cmd.ExecuteContext(ctx)
+	}()
+
+	// Give the FUSE server a moment to start up and stabilize
+	time.Sleep(3 * time.Second)
+
+	// Check that the mount is active.
+	mounted, err := isMounted(mountDir)
+	if err != nil {
+		t.Fatalf("Failed to check if mounted: %v", err)
+	}
+	if !mounted {
+		t.Errorf("Mount directory does not appear to be mounted.")
+	}
+
+
+	// Cancel the context to stop the command
+	cancel()
+
+	// Wait for the command to exit
+	select {
+	case err := <-cmdErrCh:
+		if err != nil && err != context.Canceled {
+			t.Errorf("Mount command returned an unexpected error: %v", err)
+		}
+	case <-time.After(2 * time.Second):
+		t.Error("Mount command did not exit after context was canceled.")
+	}
+
+	// Give the filesystem a moment to unmount.
+	time.Sleep(1 * time.Second)
+
+
+	// Verify that the mount point is now unmounted.
+	mounted, err = isMounted(mountDir)
+	if err != nil {
+		t.Fatalf("Failed to check if unmounted: %v", err)
+	}
+	if mounted {
+		// As a fallback, try to unmount it manually.
+		server, _ := fuse.NewServer(nil, mountDir, nil)
+		server.Unmount()
+		t.Errorf("Mount directory was not unmounted cleanly.")
+	}
+}
+
+// isMounted checks if a directory is a FUSE mount point.
+// This is a simple heuristic and might not be 100% reliable.
+func isMounted(path string) (bool, error) {
+	// On Linux, we can check the mountinfo.
+	if runtime.GOOS == "linux" {
+		data, err := os.ReadFile("/proc/self/mountinfo")
+		if err != nil {
+			return false, err
+		}
+		return strings.Contains(string(data), path) && strings.Contains(string(data), "fuse"), nil
+	}
+	return false, nil // Not implemented for other OSes.
+}

cmd/unmount.go

@@ -0,0 +1,50 @@
+package cmd
+
+import (
+	"fmt"
+	"os/exec"
+	"runtime"
+
+	"github.com/hanwen/go-fuse/v2/fuse"
+	"github.com/spf13/cobra"
+)
+
+var unmountCmd = NewUnmountCmd()
+
+func NewUnmountCmd() *cobra.Command {
+	cmd := &cobra.Command{
+		Use:   "unmount [mountpoint]",
+		Short: "Unmount a filesystem",
+		Args:  cobra.ExactArgs(1),
+		RunE: func(cmd *cobra.Command, args []string) error {
+			mountpoint := args[0]
+			server, _ := fuse.NewServer(nil, mountpoint, nil)
+			err := server.Unmount()
+			if err == nil {
+				return nil
+			}
+
+			// Fallback to system commands
+			var unmountCmd *exec.Cmd
+			switch runtime.GOOS {
+			case "linux":
+				unmountCmd = exec.Command("fusermount", "-u", mountpoint)
+			case "darwin":
+				unmountCmd = exec.Command("umount", mountpoint)
+			default:
+				return fmt.Errorf("unmount not supported on %s: %v", runtime.GOOS, err)
+			}
+
+			return unmountCmd.Run()
+		},
+	}
+	return cmd
+}
+
+func GetUnmountCmd() *cobra.Command {
+	return unmountCmd
+}
+
+func init() {
+	RootCmd.AddCommand(GetUnmountCmd())
+}

go.mod

@@ -34,6 +34,7 @@ require (
 	github.com/google/go-querystring v1.1.0 // indirect
 	github.com/google/uuid v1.6.0 // indirect
 	github.com/gorilla/websocket v1.5.3 // indirect
+	github.com/hanwen/go-fuse/v2 v2.9.0 // indirect
 	github.com/inconshreveable/mousetrap v1.1.0 // indirect
 	github.com/jbenet/go-context v0.0.0-20150711004518-d14ea06fba99 // indirect
 	github.com/jchv/go-winloader v0.0.0-20210711035445-715c2860da7e // indirect

go.sum

@@ -59,6 +59,8 @@ github.com/google/uuid v1.6.0 h1:NIvaJDMOsjHA8n1jAhLSgzrAzy1Hgr+hNrb57e+94F0=
 github.com/google/uuid v1.6.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
 github.com/gorilla/websocket v1.5.3 h1:saDtZ6Pbx/0u+bgYQ3q96pZgCzfhKXGPqt7kZ72aNNg=
 github.com/gorilla/websocket v1.5.3/go.mod h1:YR8l580nyteQvAITg2hZ9XVh4b55+EU/adAjf1fMHhE=
+github.com/hanwen/go-fuse/v2 v2.9.0 h1:0AOGUkHtbOVeyGLr0tXupiid1Vg7QB7M6YUcdmVdC58=
+github.com/hanwen/go-fuse/v2 v2.9.0/go.mod h1:yE6D2PqWwm3CbYRxFXV9xUd8Md5d6NG0WBs5spCswmI=
 github.com/inconshreveable/mousetrap v1.1.0 h1:wN+x4NVGpMsO7ErUn/mUI3vEoE6Jt13X2s0bqwp9tc8=
 github.com/inconshreveable/mousetrap v1.1.0/go.mod h1:vpF70FUmC8bwa3OWnCshd2FqLfsEA9PFc4w1p2J65bw=
 github.com/jbenet/go-context v0.0.0-20150711004518-d14ea06fba99 h1:BQSFePA1RWJOlocH6Fxy8MmwDt+yVQYULKfN0RoTN8A=