Merge release-20200115.0-34-g1040159 (automated)

1 files changed, 25 insertions, 3 deletions

diff --git a/pkg/sentry/fs/proc/mounts.go b/pkg/sentry/fs/proc/mounts.go
index 5aedae799..d4efc86e0 100644
--- a/pkg/sentry/fs/proc/mounts.go
+++ b/pkg/sentry/fs/proc/mounts.go
@@ -18,6 +18,7 @@ import (
 	"bytes"
 	"fmt"
 	"sort"
+	"strings"
 
 	"gvisor.dev/gvisor/pkg/sentry/context"
 	"gvisor.dev/gvisor/pkg/sentry/fs"
@@ -146,14 +147,35 @@ func (mif *mountInfoFile) ReadSeqFileData(ctx context.Context, handle seqfile.Se
 		// (10) Mount source: filesystem-specific information or "none".
 		fmt.Fprintf(&buf, "none ")
 
-		// (11) Superblock options. Only "ro/rw" is supported for now,
-		// and is the same as the filesystem option.
-		fmt.Fprintf(&buf, "%s\n", opts)
+		// (11) Superblock options, and final newline.
+		fmt.Fprintf(&buf, "%s\n", superBlockOpts(mountPath, mroot.Inode.MountSource))
 	})
 
 	return []seqfile.SeqData{{Buf: buf.Bytes(), Handle: (*mountInfoFile)(nil)}}, 0
 }
 
+func superBlockOpts(mountPath string, msrc *fs.MountSource) string {
+	// gVisor doesn't (yet) have a concept of super block options, so we
+	// use the ro/rw bit from the mount flag.
+	opts := "rw"
+	if msrc.Flags.ReadOnly {
+		opts = "ro"
+	}
+
+	// NOTE(b/147673608): If the mount is a cgroup, we also need to include
+	// the cgroup name in the options. For now we just read that from the
+	// path.
+	// TODO(gvisor.dev/issues/190): Once gVisor has full cgroup support, we
+	// should get this value from the cgroup itself, and not rely on the
+	// path.
+	if msrc.FilesystemType == "cgroup" {
+		splitPath := strings.Split(mountPath, "/")
+		cgroupType := splitPath[len(splitPath)-1]
+		opts += "," + cgroupType
+	}
+	return opts
+}
+
 // mountsFile is used to implement /proc/[pid]/mounts.
 //
 // +stateify savable