When there is lots of open space in a CBFS it is normally padded with
'empty' files so that sequentially scanning the CBFS can skip from one to
the next without a break.
Add support for this.
Signed-off-by: Simon Glass
---
Changes in v2: None
tools/binman/cbfs_util.py | 68 --
tools/binman/cbfs_util_test.py | 23 +++-
2 files changed, 87 insertions(+), 4 deletions(-)
diff --git a/tools/binman/cbfs_util.py b/tools/binman/cbfs_util.py
index 197cff89509..ec4a2e5a8c6 100644
--- a/tools/binman/cbfs_util.py
+++ b/tools/binman/cbfs_util.py
@@ -11,7 +11,8 @@ The format is somewhat defined by documentation in the
coreboot tree although
it is necessary to rely on the C structures and source code (mostly cbfstool)
to fully understand it.
-Currently supported: raw and stage types with compression
+Currently supported: raw and stage types with compression, padding empty areas
+with empty files
"""
from __future__ import print_function
@@ -102,6 +103,7 @@ ARCH_NAMES = {
TYPE_CBFSHEADER = 0x02 # Master header, HEADER_FORMAT
TYPE_STAGE = 0x10 # Stage, holding an executable, see STAGE_FORMAT
TYPE_RAW= 0x50 # Raw file, possibly compressed
+TYPE_EMPTY = 0x # Empty data
# Compression types
COMPRESS_NONE, COMPRESS_LZMA, COMPRESS_LZ4 = range(3)
@@ -152,6 +154,19 @@ def align_int(val, align):
"""
return int((val + align - 1) / align) * align
+def align_int_down(val, align):
+"""Align a value down to the given alignment
+
+Args:
+val: Integer value to align
+align: Integer alignment value (e.g. 4 to align to 4-byte boundary)
+
+Returns:
+integer value aligned to the required boundary, rounding down if
+necessary
+"""
+return int(val / align) * align
+
def _pack_string(instr):
"""Pack a string to the required aligned size by adding padding
@@ -184,6 +199,9 @@ class CbfsFile(object):
entry: Entry address in memory if known, else None. This is where
execution starts after the file is loaded
base_address: Base address to use for 'stage' files
+erase_byte: Erase byte to use for padding between the file header and
+contents (used for empty files)
+size: Size of the file in bytes (used for empty files)
"""
def __init__(self, name, ftype, data, compress=COMPRESS_NONE):
self.name = name
@@ -196,6 +214,8 @@ class CbfsFile(object):
self.entry = None
self.base_address = None
self.data_len = 0
+self.erase_byte = None
+self.size = None
def decompress(self):
"""Handle decompressing data if necessary"""
@@ -242,6 +262,24 @@ class CbfsFile(object):
"""
return CbfsFile(name, TYPE_RAW, data, compress)
+@classmethod
+def empty(cls, space_to_use, erase_byte):
+"""Create a new empty file of a given size
+
+Args:
+space_to_use:: Size of available space, which must be at least as
+large as the alignment size for this CBFS
+erase_byte: Byte to use for contents of file (repeated through the
+whole file)
+
+Returns:
+CbfsFile object containing the file information
+"""
+cfile = CbfsFile('', TYPE_EMPTY, b'')
+cfile.size = space_to_use - FILE_HEADER_LEN - FILENAME_ALIGN
+cfile.erase_byte = erase_byte
+return cfile
+
def get_data(self):
"""Obtain the contents of the file, in CBFS format
@@ -270,6 +308,8 @@ class CbfsFile(object):
attr = struct.pack(ATTR_COMPRESSION_FORMAT,
FILE_ATTR_TAG_COMPRESSION, ATTR_COMPRESSION_LEN,
self.compress, len(orig_data))
+elif self.ftype == TYPE_EMPTY:
+data = tools.GetBytes(self.erase_byte, self.size)
else:
raise ValueError('Unknown type %#x when writing\n' % self.ftype)
if attr:
@@ -357,6 +397,24 @@ class CbfsWriter(object):
(offset, fd.tell()))
fd.write(tools.GetBytes(self._erase_byte, offset - fd.tell()))
+def _pad_to(self, fd, offset):
+"""Write out pad bytes and/or an empty file until a given offset
+
+Args:
+fd: File objext to write to
+offset: Offset to write to
+"""
+self._align_to(fd, self._align)
+upto = fd.tell()
+if upto > offset:
+raise ValueError('No space for data before pad offset %#x (current
offset %#x)' %
+ (offset, upto))
+todo = align_int_down(offset - upto, self._align)
+if todo:
+cbf = CbfsFile.empty(todo, self._erase_byte)
+fd.write(cbf.get_data())
+self._skip_to(fd, offset)
+
def _align_to(self, fd, align):
"""Write out pad bytes until a given alignment is
