1 files changed, 25 insertions, 0 deletions
diff --git a/cmd/sharefs/fuse.go b/cmd/sharefs/fuse.go
index bbbc1446..9a0a0149 100644
--- a/cmd/sharefs/fuse.go
+++ b/cmd/sharefs/fuse.go
@@ -53,6 +53,9 @@ type (
 		// Whether sharefs_init failed.
 		initFailed bool
 
+		// Whether to create source directory as root.
+		mkdir bool
+
 		// Open file descriptor to fuse.
 		Fuse int
 
@@ -157,6 +160,9 @@ func parseOpts(args *fuseArgs, setup *setupState, log *log.Logger) (ok bool) {
 		// Pathname to writable source directory.
 		source *C.char
 
+		// Whether to create source directory as root.
+		mkdir C.int
+
 		// Decimal string representation of uid to set when running as root.
 		setuid *C.char
 		// Decimal string representation of gid to set when running as root.
@@ -169,6 +175,7 @@ func parseOpts(args *fuseArgs, setup *setupState, log *log.Logger) (ok bool) {
 
 	if C.fuse_opt_parse(args, unsafe.Pointer(&unsafeOpts), &[]C.struct_fuse_opt{
 		{templ: C.CString("source=%s"), offset: C.ulong(unsafe.Offsetof(unsafeOpts.source)), value: 0},
+		{templ: C.CString("mkdir"), offset: C.ulong(unsafe.Offsetof(unsafeOpts.mkdir)), value: 1},
 		{templ: C.CString("setuid=%s"), offset: C.ulong(unsafe.Offsetof(unsafeOpts.setuid)), value: 0},
 		{templ: C.CString("setgid=%s"), offset: C.ulong(unsafe.Offsetof(unsafeOpts.setgid)), value: 0},
 
@@ -223,6 +230,7 @@ func parseOpts(args *fuseArgs, setup *setupState, log *log.Logger) (ok bool) {
 	} else {
 		setup.Source = a
 	}
+	setup.mkdir = unsafeOpts.mkdir != 0
 
 	if unsafeOpts.setuid == nil {
 		setup.Setuid = -1
@@ -339,6 +347,9 @@ func _main(s ...string) (exitCode int) {
 	} else if setup.Fuse < 3 && (setup.Setuid > 0 || setup.Setgid > 0) {
 		log.Println("setuid and setgid has no effect when not starting as root")
 		return 1
+	} else if setup.mkdir {
+		log.Println("mkdir has no effect when not starting as root")
+		return 1
 	}
 
 	op := C.struct_fuse_operations{
@@ -387,6 +398,20 @@ func _main(s ...string) (exitCode int) {
 				log.Println("setuid and setgid must not be 0")
 				return 5
 			}
+
+			if setup.mkdir {
+				if err := os.MkdirAll(setup.Source.String(), 0700); err != nil {
+					if !errors.Is(err, os.ErrExist) {
+						log.Println(err)
+						return 5
+					}
+					// skip setup for existing source directory
+				} else if err = os.Chown(setup.Source.String(), setup.Setuid, setup.Setgid); err != nil {
+					log.Println(err)
+					return 5
+				}
+			}
+
 			if err := syscall.Setresgid(setup.Setgid, setup.Setgid, setup.Setgid); err != nil {
 				log.Printf("cannot set gid: %v", err)
 				return 5