Support for booting without initramfs

Previously when initramfs-* was not found in a deployment's
boot directory, it was assumed that rootfs is prepared for
ostree booting by a kernel patch.

With this patch, the behaviour changes to be - if initramfs-*
is not found, assume that system is using a static
ostree-prepare-root as init process. Booting without initramfs
is a common use case on embedded systems. This approach is
also more convenient, than having to patch the kernel.

Closes: #1401
Approved by: cgwalters

src/boot/grub2/ostree-grub-generator

@@ -28,7 +28,7 @@ entries_path=$(dirname $new_grub2_cfg)/entries
 
 read_config()
 {
-    config_file=${entries_path}/${1}
+    config_file=${1}
     title=""
     initrd=""
     options=""
@@ -67,11 +67,13 @@ populate_menu()
     else
         boot_prefix="${OSTREE_BOOT_PARTITION}"
     fi
-    for config in $(ls ${entries_path}); do
+    for config in $(ls $entries_path/*.conf); do
         read_config ${config}
         menu="${menu}menuentry '${title}' {\n"
         menu="${menu}\t linux ${boot_prefix}${linux} ${options}\n"
-        menu="${menu}\t initrd ${boot_prefix}${initrd}\n"
+        if [ -n "${initrd}" ] ; then
+            menu="${menu}\t initrd ${boot_prefix}${initrd}\n"
+        fi
         menu="${menu}}\n\n"
     done
     # The printf command seems to be more reliable across shells for special character (\n, \t) evaluation

src/libostree/ostree-sysroot-deploy.c

@@ -1700,21 +1700,29 @@ install_deployment_kernel (OstreeSysroot   *sysroot,
   g_autofree char * boot_relpath = g_strconcat ("/", bootcsumdir, "/", kernel_layout->kernel_namever, NULL);
   ostree_bootconfig_parser_set (bootconfig, "linux", boot_relpath);
 
+  val = ostree_bootconfig_parser_get (bootconfig, "options");
+  g_autoptr(OstreeKernelArgs) kargs = _ostree_kernel_args_from_string (val);
+
   if (kernel_layout->initramfs_namever)
     {
       g_autofree char * boot_relpath = g_strconcat ("/", bootcsumdir, "/", kernel_layout->initramfs_namever, NULL);
       ostree_bootconfig_parser_set (bootconfig, "initrd", boot_relpath);
     }
-
-  val = ostree_bootconfig_parser_get (bootconfig, "options");
+  else
+    {
+      g_autofree char *prepare_root_arg = NULL;
+      prepare_root_arg = g_strdup_printf ("init=/ostree/boot.%d/%s/%s/%d/usr/lib/ostree/ostree-prepare-root",
+                                             new_bootversion, osname, bootcsum,
+                                             ostree_deployment_get_bootserial (deployment));
+      _ostree_kernel_args_replace_take (kargs, g_steal_pointer (&prepare_root_arg));
+    }
 
   /* Note this is parsed in ostree-impl-system-generator.c */
   g_autofree char *ostree_kernel_arg = g_strdup_printf ("ostree=/ostree/boot.%d/%s/%s/%d",
                                        new_bootversion, osname, bootcsum,
                                        ostree_deployment_get_bootserial (deployment));
-  g_autoptr(OstreeKernelArgs) kargs = _ostree_kernel_args_from_string (val);
-  _ostree_kernel_args_replace_take (kargs, ostree_kernel_arg);
-  ostree_kernel_arg = NULL;
+  _ostree_kernel_args_replace_take (kargs, g_steal_pointer (&ostree_kernel_arg));
+
   g_autofree char *options_key = _ostree_kernel_args_to_string (kargs);
   ostree_bootconfig_parser_set (bootconfig, "options", options_key);