ipc: umount all mounts before removing temp dirs

This is needed if unshare(CLONE_NEWNS) is not implemented.
Otherwise, os.RemoveAll fails.

1 files changed, 14 insertions, 0 deletions

diff --git a/fileutil/fileutil.go b/fileutil/fileutil.go
index a019a14ea..b84088354 100644
--- a/fileutil/fileutil.go
+++ b/fileutil/fileutil.go
@@ -12,6 +12,7 @@ import (
 	"strconv"
 	"sync"
 	"syscall"
+	"unsafe"
 )
 
 var copyMu sync.Mutex
@@ -103,3 +104,16 @@ func ProcessTempDir(where string) (string, int, error) {
 	}
 	return "", 0, fmt.Errorf("too many live instances")
 }
+
+// UmountAll recurusively unmounts all mounts in dir.
+func UmountAll(dir string) {
+	files, _ := ioutil.ReadDir(dir)
+	for _, f := range files {
+		name := filepath.Join(dir, f.Name())
+		if f.IsDir() {
+			UmountAll(name)
+		}
+		fn := []byte(name + "\x00")
+		syscall.Syscall(syscall.SYS_UMOUNT2, uintptr(unsafe.Pointer(&fn[0])), syscall.MNT_FORCE, 0)
+	}
+}