efi_loader: open_info in OpenProtocol

efi_open_protocol has to keep track of opened protocols.

OpenProtocol enters the agent and controller handle
information into this list.

A unit test is supplied with a subsequent patch.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: Alexander Graf <agraf@suse.de>

diff --git a/lib/efi_loader/efi_boottime.c b/lib/efi_loader/efi_boottime.c
index 8fb4e3e..ce3ae23 100644 (file)
--- a/lib/efi_loader/efi_boottime.c
+++ b/lib/efi_loader/efi_boottime.c
@@ -2123,6 +2123,101 @@ static void EFIAPI efi_set_mem(void *buffer, size_t size, uint8_t value)
 /*
  * Open protocol interface on a handle.
  *
+ * @handler            handler of a protocol
+ * @protocol_interface interface implementing the protocol
+ * @agent_handle       handle of the driver
+ * @controller_handle  handle of the controller
+ * @attributes         attributes indicating how to open the protocol
+ * @return             status code
+ */
+static efi_status_t efi_protocol_open(
+                       struct efi_handler *handler,
+                       void **protocol_interface, void *agent_handle,
+                       void *controller_handle, uint32_t attributes)
+{
+       struct efi_open_protocol_info_item *item;
+       struct efi_open_protocol_info_entry *match = NULL;
+       bool opened_by_driver = false;
+       bool opened_exclusive = false;
+
+       /* If there is no agent, only return the interface */
+       if (!agent_handle)
+               goto out;
+
+       /* For TEST_PROTOCOL ignore interface attribute */
+       if (attributes != EFI_OPEN_PROTOCOL_TEST_PROTOCOL)
+               *protocol_interface = NULL;
+
+       /*
+        * Check if the protocol is already opened by a driver with the same
+        * attributes or opened exclusively
+        */
+       list_for_each_entry(item, &handler->open_infos, link) {
+               if (item->info.agent_handle == agent_handle) {
+                       if ((attributes & EFI_OPEN_PROTOCOL_BY_DRIVER) &&
+                           (item->info.attributes == attributes))
+                               return EFI_ALREADY_STARTED;
+               }
+               if (item->info.attributes & EFI_OPEN_PROTOCOL_EXCLUSIVE)
+                       opened_exclusive = true;
+       }
+
+       /* Only one controller can open the protocol exclusively */
+       if (opened_exclusive && attributes &
+           (EFI_OPEN_PROTOCOL_EXCLUSIVE | EFI_OPEN_PROTOCOL_BY_DRIVER))
+               return EFI_ACCESS_DENIED;
+
+       /* Prepare exclusive opening */
+       if (attributes & EFI_OPEN_PROTOCOL_EXCLUSIVE) {
+               /* Try to disconnect controllers */
+               list_for_each_entry(item, &handler->open_infos, link) {
+                       if (item->info.attributes ==
+                                       EFI_OPEN_PROTOCOL_BY_DRIVER)
+                               EFI_CALL(efi_disconnect_controller(
+                                               item->info.controller_handle,
+                                               item->info.agent_handle,
+                                               NULL));
+               }
+               opened_by_driver = false;
+               /* Check if all controllers are disconnected */
+               list_for_each_entry(item, &handler->open_infos, link) {
+                       if (item->info.attributes & EFI_OPEN_PROTOCOL_BY_DRIVER)
+                               opened_by_driver = true;
+               }
+               /* Only one controller can be conncected */
+               if (opened_by_driver)
+                       return EFI_ACCESS_DENIED;
+       }
+
+       /* Find existing entry */
+       list_for_each_entry(item, &handler->open_infos, link) {
+               if (item->info.agent_handle == agent_handle &&
+                   item->info.controller_handle == controller_handle)
+                       match = &item->info;
+       }
+       /* None found, create one */
+       if (!match) {
+               match = efi_create_open_info(handler);
+               if (!match)
+                       return EFI_OUT_OF_RESOURCES;
+       }
+
+       match->agent_handle = agent_handle;
+       match->controller_handle = controller_handle;
+       match->attributes = attributes;
+       match->open_count++;
+
+out:
+       /* For TEST_PROTOCOL ignore interface attribute. */
+       if (attributes != EFI_OPEN_PROTOCOL_TEST_PROTOCOL)
+               *protocol_interface = handler->protocol_interface;
+
+       return EFI_SUCCESS;
+}
+
+/*
+ * Open protocol interface on a handle.
+ *
  * This function implements the OpenProtocol interface.
  * See the Unified Extensible Firmware Interface (UEFI) specification
  * for details.
@@ -2161,12 +2256,16 @@ static efi_status_t EFIAPI efi_open_protocol(
        case EFI_OPEN_PROTOCOL_BY_CHILD_CONTROLLER:
                if (controller_handle == handle)
                        goto out;
+               /* fall-through */
        case EFI_OPEN_PROTOCOL_BY_DRIVER:
        case EFI_OPEN_PROTOCOL_BY_DRIVER | EFI_OPEN_PROTOCOL_EXCLUSIVE:
-               if (controller_handle == NULL)
+               /* Check that the controller handle is valid */
+               if (!efi_search_obj(controller_handle))
                        goto out;
+               /* fall-through */
        case EFI_OPEN_PROTOCOL_EXCLUSIVE:
-               if (agent_handle == NULL)
+               /* Check that the agent handle is valid */
+               if (!efi_search_obj(agent_handle))
                        goto out;
                break;
        default:
@@ -2177,8 +2276,8 @@ static efi_status_t EFIAPI efi_open_protocol(
        if (r != EFI_SUCCESS)
                goto out;
 
-       if (attributes != EFI_OPEN_PROTOCOL_TEST_PROTOCOL)
-               *protocol_interface = handler->protocol_interface;
+       r = efi_protocol_open(handler, protocol_interface, agent_handle,
+                             controller_handle, attributes);
 out:
        return EFI_EXIT(r);
 }