initramfs: Use dracut args from commitmeta if available

This is the second half of the previous commit. We check if the
canonical dracut args are available in the commit metadata, and prefer
those over using `--rebuild`. The latter is delegated as a backcompat
fallback.

src/daemon/rpmostree-sysroot-upgrader.c

@@ -1060,6 +1060,7 @@ perform_local_assembly (RpmOstreeSysrootUpgrader *self,
     rpmostree_context_get_kernel_changed (self->ctx) ||
     rpmostree_origin_get_regenerate_initramfs (self->origin);
   g_autoptr(GVariant) kernel_state = NULL;
+  g_autoptr(GPtrArray) initramfs_args = g_ptr_array_new_with_free_func (g_free);
   const char *bootdir = NULL;
   const char *kver = NULL;
   const char *kernel_path = NULL;
@@ -1069,9 +1070,30 @@ perform_local_assembly (RpmOstreeSysrootUpgrader *self,
       kernel_state = rpmostree_find_kernel (self->tmprootfs_dfd, cancellable, error);
       if (!kernel_state)
         return FALSE;
+
+      /* note we extract the initramfs path here but we only use it as a fallback to use
+       * with `--rebuild` if we're missing `initramfs-args` in the commit metadata -- in the
+       * future, we could remove this entirely */
       g_variant_get (kernel_state, "(&s&s&sm&s)",
                      &kver, &bootdir,
                      &kernel_path, &initramfs_path);
+
+      /* also try to extract initramfs args from the base commit */
+      g_autoptr(GVariant) base_commit = NULL;
+      if (!ostree_repo_load_variant (self->repo, OSTREE_OBJECT_TYPE_COMMIT,
+                                     self->base_revision, &base_commit, error))
+        return FALSE;
+
+      g_autoptr(GVariant) metadata = g_variant_get_child_value (base_commit, 0);
+      g_autoptr(GVariantDict) metadata_dict = g_variant_dict_new (metadata);
+
+      g_autofree char **args = NULL;
+      if (g_variant_dict_lookup (metadata_dict, "rpmostree.initramfs-args", "^a&s", &args))
+        {
+          initramfs_path = NULL;
+          for (char **it = args; it && *it; it++)
+            g_ptr_array_add (initramfs_args, g_strdup (*it));
+        }
     }
 
   /* If *just* the kernel changed, all we need to do is run depmod here.
@@ -1087,9 +1109,13 @@ perform_local_assembly (RpmOstreeSysrootUpgrader *self,
 
   if (kernel_or_initramfs_changed)
     {
+      /* append the extra args */
       const char *const* add_dracut_argv = NULL;
       if (rpmostree_origin_get_regenerate_initramfs (self->origin))
          add_dracut_argv = rpmostree_origin_get_initramfs_args (self->origin);
+      for (char **it = (char**)add_dracut_argv; it && *it; it++)
+        g_ptr_array_add (initramfs_args, g_strdup (*it));
+      g_ptr_array_add (initramfs_args, NULL);
 
       g_auto(RpmOstreeProgress) task = { 0, };
       rpmostree_output_task_begin (&task, "Generating initramfs");
@@ -1100,7 +1126,9 @@ perform_local_assembly (RpmOstreeSysrootUpgrader *self,
       /* NB: We only use the real root's /etc if initramfs regeneration is explicitly
        * requested. IOW, just replacing the kernel still gets use stock settings, like the
        * server side. */
-      if (!rpmostree_run_dracut (self->tmprootfs_dfd, add_dracut_argv, kver, initramfs_path,
+      if (!rpmostree_run_dracut (self->tmprootfs_dfd,
+                                 (const char* const*)initramfs_args->pdata,
+                                 kver, initramfs_path,
                                  rpmostree_origin_get_regenerate_initramfs (self->origin),
                                  NULL, &initramfs_tmpf, cancellable, error))
         return FALSE;

src/libpriv/rpmostree-kernel.c

@@ -514,11 +514,8 @@ rpmostree_run_dracut (int     rootfs_dfd,
                                               error))
     return FALSE;
 
-  /* Previously we used to error out if argv or rebuild_from_initramfs were both
-   * not set; now we simply use the defaults (which in Fedora today also means
-   * implicitly hostonly). That case is for `rpm-ostree override replace
-   * kernel.*.x86_64.rpm`.
-   */
+  /* Note rebuild_from_initramfs now is only used as a fallback in the client-side regen
+   * path when we can't fetch the canonical initramfs args to use. */
 
   if (rebuild_from_initramfs)
     {

tests/vmcheck/test-override-kernel.sh

@@ -69,3 +69,7 @@ vm_cmd lsinitrd ${newroot}/usr/lib/modules/${kernel_release}/initramfs.img > lsi
 assert_file_has_content_literal lsinitrd.txt etc/foobar.conf
 
 echo "ok override kernel with custom initramfs args"
+
+# FCOS omits lvm; check that we still omit lvm here too
+assert_file_has_content_literal lsinitrd.txt "--omit 'lvm'"
+echo "ok override kernel uses base initramfs args"