libmount: add mnt_fs_get_propagation()

Signed-off-by: Karel Zak <kzak@redhat.com>

1 files changed, 35 insertions, 0 deletions

diff --git a/libmount/src/fs.c b/libmount/src/fs.c
index 5c1a1074a..232a2f618 100644
--- a/libmount/src/fs.c
+++ b/libmount/src/fs.c
@@ -490,6 +490,41 @@ static int mnt_fs_get_flags(struct libmnt_fs *fs)
 }
 
 /**
+ * mnt_fs_get_propagation:
+ * @fs: mountinfo entry
+ * @flags: returns propagation MS_* flags as present in mountinfo file
+ *
+ * Note that this function set @flags to zero if not found any propagation flag
+ * in mountinfo file. The kernel default is MS_PRIVATE, this flag is not stored
+ * in the mountinfo file.
+ *
+ * Returns: 0 on success or negative number in case of error.
+ */
+int mnt_fs_get_propagation(struct libmnt_fs *fs, unsigned long *flags)
+{
+	if (!fs || !flags)
+		return -EINVAL;
+
+	*flags = 0;
+
+	if (!fs->opt_fields)
+		return 0;
+
+	 /*
+	 * The optional fields format is incompatible with mount options
+	 * ... we have to parse the field here.
+	 */
+	*flags |= strstr(fs->opt_fields, "shared:") ? MS_SHARED : MS_PRIVATE;
+
+	if (strstr(fs->opt_fields, "master:"))
+		*flags |= MS_SLAVE;
+	if (strstr(fs->opt_fields, "unbindable"))
+		*flags |= MS_UNBINDABLE;
+
+	return 0;
+}
+
+/**
  * mnt_fs_is_kernel:
  * @fs: filesystem
  *