EFI file protocols. More...

Functions
	FILE_LICENCE (GPL2_OR_LATER_OR_UBDL)

int	efi_file_install (EFI_HANDLE handle)
	Install EFI simple file system protocol. More...

void	efi_file_uninstall (EFI_HANDLE handle)
	Uninstall EFI simple file system protocol. More...

Detailed Description

EFI file protocols.

Definition in file efi_file.h.

Function Documentation

◆ FILE_LICENCE()

FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL )

◆ efi_file_install()

int efi_file_install ( EFI_HANDLE handle )

Install EFI simple file system protocol.

Parameters

handle EFI handle

Return values

rc	Return status code

Definition at line 1115 of file efi_file.c.

                                            {
         EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
         union {
                 EFI_DISK_IO_PROTOCOL *diskio;
                 void *interface;
         } diskio;
         struct image *image;
         EFI_STATUS efirc;
         int rc;
 
         /* Reset root directory state */
         efi_file_root.pos = 0;
 
         /* Install the simple file system protocol, block I/O
          * protocol, and disk I/O protocol.  We don't have a block
          * device, but large parts of the EDK2 codebase make the
          * assumption that file systems are normally attached to block
          * devices, and so we create a dummy block device on the same
          * handle just to keep things looking normal.
          */
         if ( ( efirc = bs->InstallMultipleProtocolInterfaces (
                         &handle,
                         &efi_block_io_protocol_guid,
                         &efi_block_io_protocol,
                         &efi_disk_io_protocol_guid,
                         &efi_disk_io_protocol,
                         &efi_simple_file_system_protocol_guid,
                         &efi_simple_file_system_protocol, NULL ) ) != 0 ) {
                 rc = -EEFI ( efirc );
                 DBGC ( handle, "Could not install simple file system "
                        "protocols: %s\n", strerror ( rc ) );
                 goto err_install;
         }
 
         /* The FAT filesystem driver has a bug: if a block device
          * contains no FAT filesystem but does have an
          * EFI_SIMPLE_FILE_SYSTEM_PROTOCOL instance, the FAT driver
          * will assume that it must have previously installed the
          * EFI_SIMPLE_FILE_SYSTEM_PROTOCOL.  This causes the FAT
          * driver to claim control of our device, and to refuse to
          * stop driving it, which prevents us from later uninstalling
          * correctly.
          *
          * Work around this bug by opening the disk I/O protocol
          * ourselves, thereby preventing the FAT driver from opening
          * it.
          *
          * Note that the alternative approach of opening the block I/O
          * protocol (and thereby in theory preventing DiskIo from
          * attaching to the block I/O protocol) causes an endless loop
          * of calls to our DRIVER_STOP method when starting the EFI
          * shell.  I have no idea why this is.
          */
         if ( ( efirc = bs->OpenProtocol ( handle, &efi_disk_io_protocol_guid,
                                           &diskio.interface, efi_image_handle,
                                           handle,
                                           EFI_OPEN_PROTOCOL_BY_DRIVER ) ) != 0){
                 rc = -EEFI ( efirc );
                 DBGC ( handle, "Could not open disk I/O protocol: %s\n",
                        strerror ( rc ) );
                 DBGC_EFI_OPENERS ( handle, handle, &efi_disk_io_protocol_guid );
                 goto err_open;
         }
         assert ( diskio.diskio == &efi_disk_io_protocol );
 
         /* Claim Linux initrd fixed device path */
         if ( ( rc = efi_file_path_claim ( &efi_file_initrd ) ) != 0 )
                 goto err_initrd_claim;
 
         /* Install Linux initrd fixed device path file if non-empty */
         for_each_image ( image ) {
                 if ( image->flags & IMAGE_HIDDEN )
                         continue;
                 if ( ( rc = efi_file_path_install ( &efi_file_initrd ) ) != 0 )
                         goto err_initrd_install;
                 break;
         }
 
         return 0;
 
         efi_file_path_uninstall ( &efi_file_initrd );
  err_initrd_install:
  err_initrd_claim:
         bs->CloseProtocol ( handle, &efi_disk_io_protocol_guid,
                             efi_image_handle, handle );
  err_open:
         bs->UninstallMultipleProtocolInterfaces (
                         handle,
                         &efi_simple_file_system_protocol_guid,
                         &efi_simple_file_system_protocol,
                         &efi_disk_io_protocol_guid,
                         &efi_disk_io_protocol,
                         &efi_block_io_protocol_guid,
                         &efi_block_io_protocol, NULL );
  err_install:
         return rc;
 }

References assert(), EFI_SYSTEM_TABLE::BootServices, EFI_BOOT_SERVICES::CloseProtocol, DBGC, DBGC_EFI_OPENERS, EEFI, efi_block_io_protocol, efi_block_io_protocol_guid, efi_disk_io_protocol, efi_disk_io_protocol_guid, efi_file_initrd, efi_file_path_claim(), efi_file_path_install(), efi_file_path_uninstall(), efi_file_root, efi_image_handle, EFI_OPEN_PROTOCOL_BY_DRIVER, efi_simple_file_system_protocol, efi_simple_file_system_protocol_guid, efi_systab, image::flags, for_each_image, handle, IMAGE_HIDDEN, EFI_BOOT_SERVICES::InstallMultipleProtocolInterfaces, NULL, EFI_BOOT_SERVICES::OpenProtocol, efi_file::pos, rc, strerror(), and EFI_BOOT_SERVICES::UninstallMultipleProtocolInterfaces.

Referenced by efi_image_exec().

◆ efi_file_uninstall()

void efi_file_uninstall ( EFI_HANDLE handle )

Uninstall EFI simple file system protocol.