syscontainers: use temporarily CLI ostree for checkouts

This is required to process Docker whiteouts files in OSTree, which are
not enabled by this patch.

There is an issue in the way the RepoCheckoutOptions object is mapped by
glib, as the C struct is using bit fields that are not supported by the
introspection, so use the CLI version of OSTree for now.

Signed-off-by: Giuseppe Scrivano <[email protected]>

Closes: projectatomic#497
Approved by: jlebon

Atomic/syscontainers.py

@@ -58,6 +58,28 @@ def __init__(self):
     def get_atomic_config_item(self, config_item):
         return util.get_atomic_config_item(config_item, atomic_config=self.atomic_config)
 
+    def _checkout_layer(self, repo, rootfs_fd, rootfs, rev):
+        OSTREE_SAFE_GLIB_REPO_CHECKOUT_OPTIONS = False
+        # There is an issue in the way the RepoCheckoutOptions is mapped by glib, as the C
+        # struct is using bit fields that are not supported by the introspection.
+        # Accessing .disable_fsync and .process_whiteouts thus results in a segfault in
+        # libostree.  Re-enable this once it gets fixed.
+        if OSTREE_SAFE_GLIB_REPO_CHECKOUT_OPTIONS:
+            options = OSTree.RepoCheckoutOptions()
+            options.overwrite_mode = OSTree.RepoCheckoutOverwriteMode.UNION_FILES
+            options.process_whiteouts = True
+            repo.checkout_tree_at(options, rootfs_fd, rootfs, rev)
+        else:
+            util.check_call(["ostree", "--repo=%s" % self._get_ostree_repo_location(),
+                             "checkout",
+                             "--union",
+                             "--whiteouts",
+                             rev,
+                             rootfs],
+                            stdin=DEVNULL,
+                            stdout=DEVNULL,
+                            stderr=DEVNULL)
+
     def set_args(self, args):
         self.args = args
 
@@ -148,19 +170,17 @@ def _checkout_system_container(self, repo, name, img, deployment, upgrade, value
         rev = repo.resolve_rev(imagebranch, False)[1]
 
         manifest = SystemContainers._get_commit_metadata(repo, rev, "docker.manifest")
-        options = OSTree.RepoCheckoutOptions()
-        options.overwrite_mode = OSTree.RepoCheckoutOverwriteMode.UNION_FILES
 
         rootfs_fd = None
         try:
             rootfs_fd = os.open(rootfs, os.O_DIRECTORY)
             if manifest is None:
-                repo.checkout_tree_at(options, rootfs_fd, rootfs, rev)
+                self._checkout_layer(repo, rootfs_fd, rootfs, rev)
             else:
                 layers = SystemContainers._get_layers_from_manifest(json.loads(manifest))
                 for layer in layers:
                     rev_layer = repo.resolve_rev("%s%s" % (OSTREE_OCIIMAGE_PREFIX, layer.replace("sha256:", "")), False)[1]
-                    repo.checkout_tree_at(options, rootfs_fd, rootfs, rev_layer)
+                    self._checkout_layer(repo, rootfs_fd, rootfs, rev_layer)
         finally:
             if rootfs_fd:
                 os.close(rootfs_fd)
@@ -247,18 +267,20 @@ def _get_system_checkout_path(self):
             self.get_atomic_config_item(["checkout_path"]) or \
             "/var/lib/containers/atomic"
 
-    def _get_ostree_repo(self):
-        if not OSTREE_PRESENT:
-            return None
-
+    def _get_ostree_repo_location(self):
         if self.user:
             home_dir = os.getenv("HOME")
-            repo_location = os.path.expanduser("%s/ostree/repo" % home_dir)
+            return os.path.expanduser("%s/ostree/repo" % home_dir)
         else:
-            repo_location = os.environ.get("ATOMIC_OSTREE_REPO") or \
-                            self.get_atomic_config_item(["ostree_repository"]) or \
-                            "/ostree/repo"
+            return os.environ.get("ATOMIC_OSTREE_REPO") or \
+                self.get_atomic_config_item(["ostree_repository"]) or \
+                "/ostree/repo"
+
+    def _get_ostree_repo(self):
+        if not OSTREE_PRESENT:
+            return None
 
+        repo_location = self._get_ostree_repo_location()
         repo = OSTree.Repo.new(Gio.File.new_for_path(repo_location))
 
         # If the repository doesn't exist at the specified location, create it