main: split doMount into its own file

Ongoing effort to reduce the size of main().

1 files changed, 221 insertions, 0 deletions

diff --git a/mount.go b/mount.go
new file mode 100644
index 0000000..56f1dc1
--- /dev/null
+++ b/mount.go
@@ -0,0 +1,221 @@
+package main
+
+import (
+	"encoding/json"
+	"log/syslog"
+	"os"
+	"os/exec"
+	"os/signal"
+	"path/filepath"
+	"strings"
+	"syscall"
+	"time"
+
+	"github.com/hanwen/go-fuse/fuse"
+	"github.com/hanwen/go-fuse/fuse/nodefs"
+	"github.com/hanwen/go-fuse/fuse/pathfs"
+
+	"github.com/rfjakob/gocryptfs/internal/configfile"
+	"github.com/rfjakob/gocryptfs/internal/cryptocore"
+	"github.com/rfjakob/gocryptfs/internal/fusefrontend"
+	"github.com/rfjakob/gocryptfs/internal/fusefrontend_reverse"
+	"github.com/rfjakob/gocryptfs/internal/tlog"
+)
+
+// doMount mounts an encrypted directory.
+// Called from main.
+func doMount(args *argContainer) int {
+	// Check mountpoint
+	if flagSet.NArg() != 2 {
+		tlog.Fatal.Printf("Usage: %s [OPTIONS] CIPHERDIR MOUNTPOINT", tlog.ProgramName)
+		os.Exit(ErrExitUsage)
+	}
+	var err error
+	args.mountpoint, err = filepath.Abs(flagSet.Arg(1))
+	if err != nil {
+		tlog.Fatal.Printf("Invalid mountpoint: %v", err)
+		os.Exit(ErrExitMountPoint)
+	}
+	if args.nonempty {
+		err = checkDir(args.mountpoint)
+	} else {
+		err = checkDirEmpty(args.mountpoint)
+	}
+	if err != nil {
+		tlog.Fatal.Printf("Invalid mountpoint: %v", err)
+		os.Exit(ErrExitMountPoint)
+	}
+	// Get master key
+	var masterkey []byte
+	var confFile *configfile.ConfFile
+	if args.masterkey != "" {
+		// "-masterkey"
+		tlog.Info.Printf("Using explicit master key.")
+		masterkey = parseMasterKey(args.masterkey)
+		tlog.Info.Printf(tlog.ColorYellow +
+			"THE MASTER KEY IS VISIBLE VIA \"ps ax\" AND MAY BE STORED IN YOUR SHELL HISTORY!\n" +
+			"ONLY USE THIS MODE FOR EMERGENCIES." + tlog.ColorReset)
+	} else if args.zerokey {
+		// "-zerokey"
+		tlog.Info.Printf("Using all-zero dummy master key.")
+		tlog.Info.Printf(tlog.ColorYellow +
+			"ZEROKEY MODE PROVIDES NO SECURITY AT ALL AND SHOULD ONLY BE USED FOR TESTING." +
+			tlog.ColorReset)
+		masterkey = make([]byte, cryptocore.KeyLen)
+	} else {
+		// Load master key from config file
+		masterkey, confFile = loadConfig(args)
+		printMasterKey(masterkey)
+	}
+	// Initialize FUSE server
+	tlog.Debug.Printf("cli args: %v", args)
+	srv := initFuseFrontend(masterkey, args, confFile)
+	tlog.Info.Println(tlog.ColorGreen + "Filesystem mounted and ready." + tlog.ColorReset)
+	// We have been forked into the background, as evidenced by the set
+	// "notifypid".
+	if args.notifypid > 0 {
+		// Chdir to the root directory so we don't block unmounting the CWD
+		os.Chdir("/")
+		// Switch to syslog
+		if !args.nosyslog {
+			tlog.Info.SwitchToSyslog(syslog.LOG_USER | syslog.LOG_INFO)
+			tlog.Debug.SwitchToSyslog(syslog.LOG_USER | syslog.LOG_DEBUG)
+			tlog.Warn.SwitchToSyslog(syslog.LOG_USER | syslog.LOG_WARNING)
+			tlog.SwitchLoggerToSyslog(syslog.LOG_USER | syslog.LOG_WARNING)
+			// Daemons should close all fds (and we don't want to get killed by
+			// SIGPIPE if any of those get closed on the other end)
+			os.Stderr.Close()
+			os.Stdout.Close()
+			os.Stdin.Close()
+		}
+		// Send SIGUSR1 to our parent
+		sendUsr1(args.notifypid)
+	}
+	// Wait for SIGINT in the background and unmount ourselves if we get it.
+	// This prevents a dangling "Transport endpoint is not connected"
+	// mountpoint if the user hits CTRL-C.
+	handleSigint(srv, args.mountpoint)
+	// Jump into server loop. Returns when it gets an umount request from the kernel.
+	srv.Serve()
+	return 0
+}
+
+// initFuseFrontend - initialize gocryptfs/fusefrontend
+// Calls os.Exit on errors
+func initFuseFrontend(key []byte, args *argContainer, confFile *configfile.ConfFile) *fuse.Server {
+	// Reconciliate CLI and config file arguments into a fusefrontend.Args struct
+	// that is passed to the filesystem implementation
+	cryptoBackend := cryptocore.BackendGoGCM
+	if args.openssl {
+		cryptoBackend = cryptocore.BackendOpenSSL
+	}
+	if args.aessiv {
+		cryptoBackend = cryptocore.BackendAESSIV
+	}
+	frontendArgs := fusefrontend.Args{
+		Cipherdir:      args.cipherdir,
+		Masterkey:      key,
+		PlaintextNames: args.plaintextnames,
+		LongNames:      args.longnames,
+		CryptoBackend:  cryptoBackend,
+	}
+	// confFile is nil when "-zerokey" or "-masterkey" was used
+	if confFile != nil {
+		// Settings from the config file override command line args
+		frontendArgs.PlaintextNames = confFile.IsFeatureFlagSet(configfile.FlagPlaintextNames)
+		if confFile.IsFeatureFlagSet(configfile.FlagAESSIV) {
+			frontendArgs.CryptoBackend = cryptocore.BackendAESSIV
+		} else if args.reverse {
+			tlog.Fatal.Printf("AES-SIV is required by reverse mode, but not enabled in the config file")
+			os.Exit(ErrExitUsage)
+		}
+	}
+	// If allow_other is set and we run as root, try to give newly created files to
+	// the right user.
+	if args.allow_other && os.Getuid() == 0 {
+		frontendArgs.PreserveOwner = true
+	}
+	jsonBytes, _ := json.MarshalIndent(frontendArgs, "", "\t")
+	tlog.Debug.Printf("frontendArgs: %s", string(jsonBytes))
+	var finalFs pathfs.FileSystem
+	if args.reverse {
+		finalFs = fusefrontend_reverse.NewFS(frontendArgs)
+	} else {
+		finalFs = fusefrontend.NewFS(frontendArgs)
+	}
+	pathFsOpts := &pathfs.PathNodeFsOptions{ClientInodes: true}
+	pathFs := pathfs.NewPathNodeFs(finalFs, pathFsOpts)
+	fuseOpts := &nodefs.Options{
+		// These options are to be compatible with libfuse defaults,
+		// making benchmarking easier.
+		NegativeTimeout: time.Second,
+		AttrTimeout:     time.Second,
+		EntryTimeout:    time.Second,
+	}
+	conn := nodefs.NewFileSystemConnector(pathFs.Root(), fuseOpts)
+	var mOpts fuse.MountOptions
+	mOpts.AllowOther = false
+	if args.allow_other {
+		tlog.Info.Printf(tlog.ColorYellow + "The option \"-allow_other\" is set. Make sure the file " +
+			"permissions protect your data from unwanted access." + tlog.ColorReset)
+		mOpts.AllowOther = true
+		// Make the kernel check the file permissions for us
+		mOpts.Options = append(mOpts.Options, "default_permissions")
+	}
+	if args.nonempty {
+		mOpts.Options = append(mOpts.Options, "nonempty")
+	}
+	// Set values shown in "df -T" and friends
+	// First column, "Filesystem"
+	mOpts.Options = append(mOpts.Options, "fsname="+args.cipherdir)
+	// Second column, "Type", will be shown as "fuse." + Name
+	mOpts.Name = "gocryptfs"
+	if args.reverse {
+		mOpts.Name += "-reverse"
+	}
+
+	// The kernel enforces read-only operation, we just have to pass "ro".
+	// Reverse mounts are always read-only
+	if args.ro || args.reverse {
+		mOpts.Options = append(mOpts.Options, "ro")
+	}
+	// Add additional mount options (if any) after the stock ones, so the user has
+	// a chance to override them.
+	if args.o != "" {
+		parts := strings.Split(args.o, ",")
+		tlog.Debug.Printf("Adding -o mount options: %v", parts)
+		mOpts.Options = append(mOpts.Options, parts...)
+	}
+	srv, err := fuse.NewServer(conn.RawFS(), args.mountpoint, &mOpts)
+	if err != nil {
+		tlog.Fatal.Printf("Mount failed: %v", err)
+		os.Exit(ErrExitMount)
+	}
+	srv.SetDebug(args.fusedebug)
+
+	// All FUSE file and directory create calls carry explicit permission
+	// information. We need an unrestricted umask to create the files and
+	// directories with the requested permissions.
+	syscall.Umask(0000)
+
+	return srv
+}
+
+func handleSigint(srv *fuse.Server, mountpoint string) {
+	ch := make(chan os.Signal, 1)
+	signal.Notify(ch, os.Interrupt)
+	signal.Notify(ch, syscall.SIGTERM)
+	go func() {
+		<-ch
+		err := srv.Unmount()
+		if err != nil {
+			tlog.Warn.Print(err)
+			tlog.Info.Printf("Trying lazy unmount")
+			cmd := exec.Command("fusermount", "-u", "-z", mountpoint)
+			cmd.Stdout = os.Stdout
+			cmd.Stderr = os.Stderr
+			cmd.Run()
+		}
+		os.Exit(1)
+	}()
+}