[efi] Provide access to files stored on EFI filesystems

Provide access to local files via the "file://" URI scheme.  There are
three syntaxes:

  - An opaque URI with a relative path (e.g. "file:script.ipxe").
    This will be interpreted as a path relative to the iPXE binary.

  - A hierarchical URI with a non-network absolute path
    (e.g. "file:/boot/script.ipxe").  This will be interpreted as a
    path relative to the root of the filesystem from which the iPXE
    binary was loaded.

  - A hierarchical URI with a network path in which the authority is a
    volume label (e.g. "file://bootdisk/script.ipxe").  This will be
    interpreted as a path relative to the root of the filesystem with
    the specified volume label.

Note that the potentially desirable shell mappings (e.g. "fs0:" and
"blk0:") are concepts internal to the UEFI shell binary, and do not
seem to be exposed in any way to external executables.  The old
EFI_SHELL_PROTOCOL (which did provide access to these mappings) is no
longer installed by current versions of the UEFI shell.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/src/config/general.h b/src/config/general.h
index e9b781fb..675c11e0 100644
--- a/src/config/general.h
+++ b/src/config/general.h
@@ -57,6 +57,7 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
 #undef	DOWNLOAD_PROTO_FTP	/* File Transfer Protocol */
 #undef	DOWNLOAD_PROTO_SLAM	/* Scalable Local Area Multicast */
 #undef	DOWNLOAD_PROTO_NFS	/* Network File System Protocol */
+//#undef DOWNLOAD_PROTO_FILE	/* Local filesystem access */
 
 /*
  * SAN boot protocols