Add (non-atomic) support for GRUB2 + UEFI

We need basic support for UEFI - many newer servers don't support
BIOS compatibility mode anymore.

However, this patch only implements non-atomic because UEFI is FAT, and
we can't do the previous design for OSTree of atomic swap of
/boot/loader.

The Fedora/RHEL UEFI layout has the kernels on a "real" /boot
partition, and /boot/efi/EFI/$vendor just holds the grub2 UEFI binary
and grub.cfg.

Following this, /boot/loader is still on the OS boot partition, and we
still atomically swap it.  This potentially paves the way to atomic
upgrades in the future.

https://bugzilla.gnome.org/show_bug.cgi?id=724246

10 files changed, 202 insertions, 42 deletions

diff --git a/src/libostree/ostree-bootloader-grub2.c b/src/libostree/ostree-bootloader-grub2.c
index 8f4dcae9..19d04924 100644
--- a/src/libostree/ostree-bootloader-grub2.c
+++ b/src/libostree/ostree-bootloader-grub2.c
@@ -35,6 +35,8 @@ struct _OstreeBootloaderGrub2
 
   OstreeSysroot  *sysroot;
   GFile          *config_path_bios;
+  GFile          *config_path_efi;
+  gboolean        is_efi;
 };
 
 typedef GObjectClass OstreeBootloaderGrub2Class;
@@ -44,11 +46,79 @@ G_DEFINE_TYPE_WITH_CODE (OstreeBootloaderGrub2, _ostree_bootloader_grub2, G_TYPE
                          G_IMPLEMENT_INTERFACE (OSTREE_TYPE_BOOTLOADER, _ostree_bootloader_grub2_bootloader_iface_init));
 
 static gboolean
-_ostree_bootloader_grub2_query (OstreeBootloader *bootloader)
+_ostree_bootloader_grub2_query (OstreeBootloader *bootloader,
+                                gboolean         *out_is_active,
+                                GCancellable     *cancellable,
+                                GError          **error)
 {
+  gboolean ret = FALSE;
   OstreeBootloaderGrub2 *self = OSTREE_BOOTLOADER_GRUB2 (bootloader);
+  gs_unref_object GFile* efi_basedir = NULL;
+  gs_unref_object GFileInfo *file_info = NULL;
+
+  if (g_file_query_exists (self->config_path_bios, NULL))
+    {
+      *out_is_active = TRUE;
+      ret = TRUE;
+      goto out;
+    }
+
+  efi_basedir = g_file_resolve_relative_path (self->sysroot->path, "boot/efi/EFI");
+
+  g_clear_object (&self->config_path_efi);
+
+  if (g_file_query_exists (efi_basedir, NULL))
+    {
+      gs_unref_object GFileEnumerator *direnum = NULL;
+
+      direnum = g_file_enumerate_children (efi_basedir, OSTREE_GIO_FAST_QUERYINFO,
+                                           G_FILE_QUERY_INFO_NOFOLLOW_SYMLINKS,
+                                           cancellable, error);
+      if (!direnum)
+        goto out;
+  
+      while (TRUE)
+        {
+          GFileInfo *file_info;
+          const char *fname;
+          gs_free char *subdir_grub_cfg = NULL;
+
+          if (!gs_file_enumerator_iterate (direnum, &file_info, NULL,
+                                           cancellable, error))
+            goto out;
+          if (file_info == NULL)
+            break;
+
+          fname = g_file_info_get_name (file_info);
+          if (strcmp (fname, "BOOT") == 0)
+            continue;
+
+          if (g_file_info_get_file_type (file_info) != G_FILE_TYPE_DIRECTORY)
+            continue;
+
+          subdir_grub_cfg = g_build_filename (gs_file_get_path_cached (efi_basedir), fname, "grub.cfg", NULL); 
+          
+          if (g_file_test (subdir_grub_cfg, G_FILE_TEST_EXISTS))
+            {
+              self->config_path_efi = g_file_new_for_path (subdir_grub_cfg);
+              break;
+            }
+        }
+
+      if (self->config_path_efi)
+        {
+          self->is_efi = TRUE;
+          *out_is_active = TRUE;
+          ret = TRUE;
+          goto out;
+        }
+    }
+  else
+    *out_is_active = FALSE;
 
-  return g_file_query_exists (self->config_path_bios, NULL);
+  ret = TRUE;
+ out:
+  return ret;
 }
 
 static const char *
@@ -58,7 +128,7 @@ _ostree_bootloader_grub2_get_name (OstreeBootloader *bootloader)
 }
 
 gboolean
-_ostree_bootloader_grub2_generate_config (OstreeBootloaderGrub2         *self,
+_ostree_bootloader_grub2_generate_config (OstreeSysroot                 *sysroot,
                                           int                            bootversion,
                                           int                            target_fd,
                                           GCancellable                  *cancellable,
@@ -70,6 +140,7 @@ _ostree_bootloader_grub2_generate_config (OstreeBootloaderGrub2         *self,
   gs_unref_ptrarray GPtrArray *loader_configs = NULL;
   guint i;
   gsize bytes_written;
+  gboolean is_efi;
   /* So... yeah.  Just going to hardcode these. */
   static const char hardcoded_video[] = "load_video\n"
     "set gfxpayload=keep\n";
@@ -83,9 +154,12 @@ _ostree_bootloader_grub2_generate_config (OstreeBootloaderGrub2         *self,
   g_assert (grub2_boot_device_id != NULL);
   g_assert (grub2_prepare_root_cache != NULL);
 
+  /* Passed from the parent */
+  is_efi = g_getenv ("_OSTREE_GRUB2_IS_EFI") != NULL;
+
   out_stream = g_unix_output_stream_new (target_fd, FALSE);
 
-  if (!_ostree_sysroot_read_boot_loader_configs (self->sysroot, bootversion,
+  if (!_ostree_sysroot_read_boot_loader_configs (sysroot, bootversion,
                                                  &loader_configs,
                                                  cancellable, error))
     goto out;
@@ -127,7 +201,10 @@ _ostree_bootloader_grub2_generate_config (OstreeBootloaderGrub2         *self,
                        "No \"linux\" key in bootloader config");
           goto out;
         }
-      g_string_append (output, "linux16 ");
+      if (is_efi)
+        g_string_append (output, "linuxefi ");
+      else
+        g_string_append (output, "linux16 ");
       g_string_append (output, kernel);
 
       options = ostree_bootconfig_parser_get (config, "options");
@@ -141,7 +218,10 @@ _ostree_bootloader_grub2_generate_config (OstreeBootloaderGrub2         *self,
       initrd = ostree_bootconfig_parser_get (config, "initrd");
       if (initrd)
         {
-          g_string_append (output, "initrd16 ");
+          if (is_efi)
+            g_string_append (output, "initrdefi ");
+          else
+            g_string_append (output, "initrd16 ");
           g_string_append (output, initrd);
           g_string_append_c (output, '\n');
         }
@@ -168,19 +248,36 @@ _ostree_bootloader_grub2_write_config (OstreeBootloader      *bootloader,
 {
   OstreeBootloaderGrub2 *self = OSTREE_BOOTLOADER_GRUB2 (bootloader);
   gboolean ret = FALSE;
+  gs_unref_object GFile *efi_new_config_temp = NULL;
+  gs_unref_object GFile *efi_orig_config = NULL;
   gs_unref_object GFile *new_config_path = NULL;
   gs_unref_object GSSubprocessContext *procctx = NULL;
   gs_unref_object GSSubprocess *proc = NULL;
   gs_strfreev char **child_env = g_get_environ ();
   gs_free char *bootversion_str = g_strdup_printf ("%u", (guint)bootversion);
+  gs_unref_object GFile *config_path_efi_dir = NULL;
 
-  new_config_path = ot_gfile_resolve_path_printf (self->sysroot->path, "boot/loader.%d/grub.cfg",
-                                                  bootversion);
+  if (self->is_efi)
+    {
+      config_path_efi_dir = g_file_get_parent (self->config_path_efi);
+      new_config_path = g_file_get_child (config_path_efi_dir, "grub.cfg.new");
+      /* We use grub2-mkconfig to write to a temporary file first */
+      if (!ot_gfile_ensure_unlinked (new_config_path, cancellable, error))
+        goto out;
+    }
+  else
+    {
+      new_config_path = ot_gfile_resolve_path_printf (self->sysroot->path, "boot/loader.%d/grub.cfg",
+                                                      bootversion);
+    }
 
   procctx = gs_subprocess_context_newv ("grub2-mkconfig", "-o",
                                         gs_file_get_path_cached (new_config_path),
                                         NULL);
   child_env = g_environ_setenv (child_env, "_OSTREE_GRUB2_BOOTVERSION", bootversion_str, TRUE);
+  /* We have to pass our state to the child */
+  if (self->is_efi)
+    child_env = g_environ_setenv (child_env, "_OSTREE_GRUB2_IS_EFI", "1", TRUE);
   gs_subprocess_context_set_environment (procctx, child_env);
   gs_subprocess_context_set_stdout_disposition (procctx, GS_SUBPROCESS_STREAM_DISPOSITION_NULL);
   if (g_getenv ("OSTREE_DEBUG_GRUB2"))
@@ -206,6 +303,29 @@ rm -f ${grub_cfg}.new
   /* Now let's fdatasync() for the new file */
   if (!gs_file_sync_data (new_config_path, cancellable, error))
     goto out;
+
+  if (self->is_efi)
+    {
+      gs_unref_object GFile *config_path_efi_old = g_file_get_child (config_path_efi_dir, "grub.cfg.old");
+      
+      /* copy current to old */
+      if (!ot_gfile_ensure_unlinked (config_path_efi_old, cancellable, error))
+        goto out;
+      if (!g_file_copy (self->config_path_efi, config_path_efi_old,
+                        G_FILE_COPY_OVERWRITE, cancellable, NULL, NULL, error))
+        goto out;
+      if (!ot_gfile_ensure_unlinked (config_path_efi_old, cancellable, error))
+        goto out;
+
+      /* NOTE: NON-ATOMIC REPLACEMENT; WE can't do anything else on FAT;
+       * see https://bugzilla.gnome.org/show_bug.cgi?id=724246
+       */
+      if (!ot_gfile_ensure_unlinked (new_config_path, cancellable, error))
+        goto out;
+      if (!gs_file_rename (new_config_path, self->config_path_efi,
+                           cancellable, error))
+        goto out;
+    }
   
   ret = TRUE;
  out:
@@ -215,7 +335,8 @@ rm -f ${grub_cfg}.new
 static gboolean
 _ostree_bootloader_grub2_is_atomic (OstreeBootloader      *bootloader) 
 {
-  return TRUE;
+  OstreeBootloaderGrub2 *self = OSTREE_BOOTLOADER_GRUB2 (bootloader);
+  return !self->is_efi;
 }
 
 static void
@@ -225,6 +346,7 @@ _ostree_bootloader_grub2_finalize (GObject *object)
 
   g_clear_object (&self->sysroot);
   g_clear_object (&self->config_path_bios);
+  g_clear_object (&self->config_path_efi);
 
   G_OBJECT_CLASS (_ostree_bootloader_grub2_parent_class)->finalize (object);
 }
diff --git a/src/libostree/ostree-bootloader-grub2.h b/src/libostree/ostree-bootloader-grub2.h
index 334ad49b..dfea1837 100644
--- a/src/libostree/ostree-bootloader-grub2.h
+++ b/src/libostree/ostree-bootloader-grub2.h
@@ -34,7 +34,7 @@ GType _ostree_bootloader_grub2_get_type (void) G_GNUC_CONST;
 
 OstreeBootloaderGrub2 * _ostree_bootloader_grub2_new (OstreeSysroot *sysroot);
 
-gboolean _ostree_bootloader_grub2_generate_config (OstreeBootloaderGrub2 *self, int bootversion, int target_fd, GCancellable *cancellable, GError **error);
+gboolean _ostree_bootloader_grub2_generate_config (OstreeSysroot *sysroot, int bootversion, int target_fd, GCancellable *cancellable, GError **error);
 
 G_END_DECLS
 
diff --git a/src/libostree/ostree-bootloader-syslinux.c b/src/libostree/ostree-bootloader-syslinux.c
index 0934bb81..86b66fa2 100644
--- a/src/libostree/ostree-bootloader-syslinux.c
+++ b/src/libostree/ostree-bootloader-syslinux.c
@@ -42,11 +42,15 @@ G_DEFINE_TYPE_WITH_CODE (OstreeBootloaderSyslinux, _ostree_bootloader_syslinux,
                          G_IMPLEMENT_INTERFACE (OSTREE_TYPE_BOOTLOADER, _ostree_bootloader_syslinux_bootloader_iface_init));
 
 static gboolean
-_ostree_bootloader_syslinux_query (OstreeBootloader *bootloader)
+_ostree_bootloader_syslinux_query (OstreeBootloader *bootloader,
+                                   gboolean         *out_is_active,
+                                   GCancellable     *cancellable,
+                                   GError          **error)
 {
   OstreeBootloaderSyslinux *self = OSTREE_BOOTLOADER_SYSLINUX (bootloader);
 
-  return g_file_query_file_type (self->config_path, G_FILE_QUERY_INFO_NOFOLLOW_SYMLINKS, NULL) == G_FILE_TYPE_SYMBOLIC_LINK;
+  *out_is_active = g_file_query_file_type (self->config_path, G_FILE_QUERY_INFO_NOFOLLOW_SYMLINKS, NULL) == G_FILE_TYPE_SYMBOLIC_LINK;
+  return TRUE;
 }
 
 static const char *
diff --git a/src/libostree/ostree-bootloader-uboot.c b/src/libostree/ostree-bootloader-uboot.c
index cd25e56f..84c5cddc 100644
--- a/src/libostree/ostree-bootloader-uboot.c
+++ b/src/libostree/ostree-bootloader-uboot.c
@@ -46,11 +46,15 @@ G_DEFINE_TYPE_WITH_CODE (OstreeBootloaderUboot, _ostree_bootloader_uboot, G_TYPE
                          G_IMPLEMENT_INTERFACE (OSTREE_TYPE_BOOTLOADER, _ostree_bootloader_uboot_bootloader_iface_init));
 
 static gboolean
-_ostree_bootloader_uboot_query (OstreeBootloader *bootloader)
+_ostree_bootloader_uboot_query (OstreeBootloader *bootloader,
+                                gboolean         *out_is_active,
+                                GCancellable     *cancellable,
+                                GError          **error) 
 {
   OstreeBootloaderUboot *self = OSTREE_BOOTLOADER_UBOOT (bootloader);
 
-  return g_file_query_file_type (self->config_path, G_FILE_QUERY_INFO_NOFOLLOW_SYMLINKS, NULL) == G_FILE_TYPE_SYMBOLIC_LINK;
+  *out_is_active = g_file_query_file_type (self->config_path, G_FILE_QUERY_INFO_NOFOLLOW_SYMLINKS, NULL) == G_FILE_TYPE_SYMBOLIC_LINK;
+  return TRUE;
 }
 
 static const char *
diff --git a/src/libostree/ostree-bootloader.c b/src/libostree/ostree-bootloader.c
index 37219999..c95674c8 100644
--- a/src/libostree/ostree-bootloader.c
+++ b/src/libostree/ostree-bootloader.c
@@ -30,11 +30,14 @@ _ostree_bootloader_default_init (OstreeBootloaderInterface *iface)
 }
 
 gboolean
-_ostree_bootloader_query (OstreeBootloader  *self)
+_ostree_bootloader_query (OstreeBootloader *self,
+                          gboolean         *out_is_active,
+                          GCancellable     *cancellable,
+                          GError          **error)
 {
   g_return_val_if_fail (OSTREE_IS_BOOTLOADER (self), FALSE);
 
-  return OSTREE_BOOTLOADER_GET_IFACE (self)->query (self);
+  return OSTREE_BOOTLOADER_GET_IFACE (self)->query (self, out_is_active, cancellable, error);
 }
 
 /**
diff --git a/src/libostree/ostree-bootloader.h b/src/libostree/ostree-bootloader.h
index a84ce6ba..cbb25aac 100644
--- a/src/libostree/ostree-bootloader.h
+++ b/src/libostree/ostree-bootloader.h
@@ -37,7 +37,10 @@ struct _OstreeBootloaderInterface
   GTypeInterface g_iface;
 
   /* virtual functions */
-  gboolean             (* query)                  (OstreeBootloader  *self);
+  gboolean             (* query)                  (OstreeBootloader *bootloader,
+                                                   gboolean         *out_is_active,
+                                                   GCancellable     *cancellable,
+                                                   GError          **error);
   const char *         (* get_name)               (OstreeBootloader  *self);
   gboolean             (* write_config)           (OstreeBootloader  *self,
                                                    int            bootversion,
@@ -48,7 +51,10 @@ struct _OstreeBootloaderInterface
 
 GType _ostree_bootloader_get_type (void) G_GNUC_CONST;
 
-gboolean _ostree_bootloader_query (OstreeBootloader *self);
+gboolean _ostree_bootloader_query (OstreeBootloader *bootloader,
+                                   gboolean         *out_is_active,
+                                   GCancellable     *cancellable,
+                                   GError          **error);
 
 const char *_ostree_bootloader_get_name (OstreeBootloader  *self);
 
diff --git a/src/libostree/ostree-cmdprivate.c b/src/libostree/ostree-cmdprivate.c
index 2bbfe332..9c2ac3bf 100644
--- a/src/libostree/ostree-cmdprivate.c
+++ b/src/libostree/ostree-cmdprivate.c
@@ -29,9 +29,7 @@
 static gboolean 
 impl_ostree_generate_grub2_config (OstreeSysroot *sysroot, int bootversion, int target_fd, GCancellable *cancellable, GError **error)
 {
-  gs_unref_object OstreeBootloaderGrub2 *grub2 = _ostree_bootloader_grub2_new (sysroot);
-
-  return _ostree_bootloader_grub2_generate_config (grub2, bootversion, target_fd, cancellable, error);
+  return _ostree_bootloader_grub2_generate_config (sysroot, bootversion, target_fd, cancellable, error);
 }
 
 /**
diff --git a/src/libostree/ostree-sysroot-deploy.c b/src/libostree/ostree-sysroot-deploy.c
index 9934e0f8..8d9fe0c7 100644
--- a/src/libostree/ostree-sysroot-deploy.c
+++ b/src/libostree/ostree-sysroot-deploy.c
@@ -1598,9 +1598,12 @@ ostree_sysroot_write_deployments (OstreeSysroot     *self,
   else
     {
       int new_bootversion = self->bootversion ? 0 : 1;
-      gs_unref_object OstreeBootloader *bootloader = _ostree_sysroot_query_bootloader (self);
+      gs_unref_object OstreeBootloader *bootloader = NULL;
       gs_unref_object GFile *new_loader_entries_dir = NULL;
 
+      if (!_ostree_sysroot_query_bootloader (self, &bootloader, cancellable, error))
+        goto out;
+
       new_loader_entries_dir = ot_gfile_resolve_path_printf (self->path, "boot/loader.%d/entries",
                                                              new_bootversion);
       if (!gs_shutil_rm_rf (new_loader_entries_dir, cancellable, error))
diff --git a/src/libostree/ostree-sysroot-private.h b/src/libostree/ostree-sysroot-private.h
index 0857e4cc..28b0feb7 100644
--- a/src/libostree/ostree-sysroot-private.h
+++ b/src/libostree/ostree-sysroot-private.h
@@ -75,7 +75,10 @@ _ostree_sysroot_get_devino (GFile         *path,
 
 char *_ostree_sysroot_join_lines (GPtrArray  *lines);
 
-OstreeBootloader *_ostree_sysroot_query_bootloader (OstreeSysroot         *sysroot);
+gboolean _ostree_sysroot_query_bootloader (OstreeSysroot     *sysroot,
+                                           OstreeBootloader **out_bootloader,
+                                           GCancellable      *cancellable,
+                                           GError           **error);
 
 G_END_DECLS
 
diff --git a/src/libostree/ostree-sysroot.c b/src/libostree/ostree-sysroot.c
index 160fc078..64a5e5bb 100644
--- a/src/libostree/ostree-sysroot.c
+++ b/src/libostree/ostree-sysroot.c
@@ -846,29 +846,46 @@ ostree_sysroot_get_repo (OstreeSysroot         *self,
 /**
  * ostree_sysroot_query_bootloader:
  * @sysroot: Sysroot
- *
- * Returns: (transfer full): Currently active bootloader in @sysroot
+ * @out_bootloader: (out) (transfer full) (allow-none): Return location for bootloader, may be %NULL
+ * @cancellable: Cancellable
+ * @error: Error
  */
-OstreeBootloader *
-_ostree_sysroot_query_bootloader (OstreeSysroot *self)
+gboolean
+_ostree_sysroot_query_bootloader (OstreeSysroot     *sysroot,
+                                  OstreeBootloader **out_bootloader,
+                                  GCancellable      *cancellable,
+                                  GError           **error)
 {
-  OstreeBootloaderSyslinux *syslinux;
-  OstreeBootloaderUboot    *uboot;
-  OstreeBootloaderGrub2    *grub2;
-
-  syslinux = _ostree_bootloader_syslinux_new (self);
-  if (_ostree_bootloader_query ((OstreeBootloader*)syslinux))
-    return (OstreeBootloader*) (syslinux);
-
-  grub2 = _ostree_bootloader_grub2_new (self);
-  if (_ostree_bootloader_query ((OstreeBootloader*)grub2))
-    return (OstreeBootloader*) (grub2);
+  gboolean ret = FALSE;
+  gboolean is_active;
+  gs_unref_object OstreeBootloader *ret_loader = NULL;
 
-  uboot = _ostree_bootloader_uboot_new (self);
-  if (_ostree_bootloader_query ((OstreeBootloader*)uboot))
-    return (OstreeBootloader*) (uboot);
+  ret_loader = (OstreeBootloader*)_ostree_bootloader_syslinux_new (sysroot);
+  if (!_ostree_bootloader_query (ret_loader, &is_active,
+                                 cancellable, error))
+    goto out;
+  if (!is_active)
+    {
+      g_object_unref (ret_loader);
+      ret_loader = (OstreeBootloader*)_ostree_bootloader_grub2_new (sysroot);
+      if (!_ostree_bootloader_query (ret_loader, &is_active,
+                                     cancellable, error))
+        goto out;
+    }
+  if (!is_active)
+    {
+      g_object_unref (ret_loader);
+      ret_loader = (OstreeBootloader*)_ostree_bootloader_uboot_new (sysroot);
+      if (!_ostree_bootloader_query (ret_loader, &is_active, cancellable, error))
+        goto out;
+    }
+  if (!is_active)
+    g_clear_object (&ret_loader);
 
-  return NULL;
+  ret = TRUE;
+  gs_transfer_out_value (out_bootloader, &ret_loader);
+ out:
+  return ret;
 }
 
 char *