binman: Support replacing data in a cbfs

At present binman cannot replace data within a CBFS since it does not
allow rewriting of the files in that CBFS. Implement this by using the
new WriteData() method to handle the case.

Add a header to compressed data so that the amount of compressed data can
be determined without reference to the size of the containing entry. This
allows the entry to be larger that the contents, without causing errors in
decompression. This is necessary to cope with a compressed device tree
being updated in such a way that it shrinks after the entry size is
already set (an obscure case). It is not used with CBFS since it has its
own metadata for this. Increase the number of passes allowed to resolve
the position of entries, to handle this case.

Add a test for this new logic.

Signed-off-by: Simon Glass <[e-mail]>

tools/binman/cbfs_util.py

···
         cbfs_offset: Offset of file data in bytes from start of CBFS, or None to
             place this file anyway
         data: Contents of file, uncompressed
+        orig_data: Original data added to the file, possibly compressed
         data_len: Length of (possibly compressed) data in bytes
         ftype: File type (TYPE_...)
         compression: Compression type (COMPRESS_...)
···
         self.offset = None
         self.cbfs_offset = cbfs_offset
         self.data = data
+        self.orig_data = data
         self.ftype = ftype
         self.compress = compress
         self.memlen = None
···
         """Handle decompressing data if necessary"""
         indata = self.data
         if self.compress == COMPRESS_LZ4:
-            data = tools.Decompress(indata, 'lz4')
+            data = tools.Decompress(indata, 'lz4', with_header=False)
         elif self.compress == COMPRESS_LZMA:
-            data = tools.Decompress(indata, 'lzma')
+            data = tools.Decompress(indata, 'lzma', with_header=False)
         else:
             data = indata
         self.memlen = len(data)
···
         elif self.ftype == TYPE_RAW:
             orig_data = data
             if self.compress == COMPRESS_LZ4:
-                data = tools.Compress(orig_data, 'lz4')
+                data = tools.Compress(orig_data, 'lz4', with_header=False)
             elif self.compress == COMPRESS_LZMA:
-                data = tools.Compress(orig_data, 'lzma')
+                data = tools.Compress(orig_data, 'lzma', with_header=False)
             self.memlen = len(orig_data)
             self.data_len = len(data)
             attr = struct.pack(ATTR_COMPRESSION_FORMAT,

tools/binman/control.py

···
     # since changing an offset from 0x100 to 0x104 (for example) can
     # alter the compressed size of the device tree. So we need a
     # third pass for this.
-    passes = 3
+    passes = 5
     for pack_pass in range(passes):
         try:
             image.PackEntries()

tools/binman/entry_test.py

···
         dtb = entry.Entry.Create(None, self.GetNode(), 'u-boot-dtb')
         self.assertEqual('u-boot-dtb', dtb.GetFdtEtype())
 
+    def testWriteChildData(self):
+        """Test the WriteChildData() method of the base class"""
+        base = entry.Entry.Create(None, self.GetNode(), 'blob-dtb')
+        self.assertTrue(base.WriteChildData(base))
+
 
 if __name__ == "__main__":
     unittest.main()

tools/binman/etype/cbfs.py

···
         self._cbfs_arg = fdt_util.GetString(node, 'cbfs-arch', 'x86')
         self._cbfs_entries = OrderedDict()
         self._ReadSubnodes()
+        self.reader = None
 
     def ObtainContents(self, skip=None):
         arch = cbfs_util.find_arch(self._cbfs_arg)
···
     def _ReadSubnodes(self):
         """Read the subnodes to find out what should go in this IFWI"""
         for node in self._node.subnodes:
-            entry = Entry.Create(self.section, node)
+            entry = Entry.Create(self, node)
             entry.ReadNode()
             entry._cbfs_name = fdt_util.GetString(node, 'cbfs-name', entry.name)
             entry._type = fdt_util.GetString(node, 'cbfs-type')

tools/binman/ftest.py

···
     def testExtractCbfsRaw(self):
         """Test extracting CBFS compressed data without decompressing it"""
         data = self._RunExtractCmd('section/cbfs/u-boot-dtb', decomp=False)
-        dtb = tools.Decompress(data, 'lzma')
+        dtb = tools.Decompress(data, 'lzma', with_header=False)
         self.assertEqual(EXTRACT_DTB_SIZE, len(dtb))
 
     def testExtractBadEntry(self):
···
         desc = entries['intel-descriptor']
         self.assertEqual(0xff800000, desc.offset);
         self.assertEqual(0xff800000, desc.image_pos);
+
+    def testReplaceCbfs(self):
+        """Test replacing a single file in CBFS without changing the size"""
+        self._CheckLz4()
+        expected = b'x' * len(U_BOOT_DATA)
+        data = self._DoReadFileRealDtb('142_replace_cbfs.dts')
+        updated_fname = tools.GetOutputFilename('image-updated.bin')
+        tools.WriteFile(updated_fname, data)
+        entry_name = 'section/cbfs/u-boot'
+        control.WriteEntry(updated_fname, entry_name, expected,
+                           allow_resize=True)
+        data = control.ReadEntry(updated_fname, entry_name)
+        self.assertEqual(expected, data)
+
+    def testReplaceResizeCbfs(self):
+        """Test replacing a single file in CBFS with one of a different size"""
+        self._CheckLz4()
+        expected = U_BOOT_DATA + b'x'
+        data = self._DoReadFileRealDtb('142_replace_cbfs.dts')
+        updated_fname = tools.GetOutputFilename('image-updated.bin')
+        tools.WriteFile(updated_fname, data)
+        entry_name = 'section/cbfs/u-boot'
+        control.WriteEntry(updated_fname, entry_name, expected,
+                           allow_resize=True)
+        data = control.ReadEntry(updated_fname, entry_name)
+        self.assertEqual(expected, data)
 
 
 if __name__ == "__main__":

tools/binman/test/142_replace_cbfs.dts

···
+// SPDX-License-Identifier: GPL-2.0+
+
+/dts-v1/;
+
+/ {
+	#address-cells = <1>;
+	#size-cells = <1>;
+
+	binman {
+		size = <0xe00>;
+		allow-repack;
+		u-boot {
+		};
+		section {
+			align = <0x100>;
+			cbfs {
+				size = <0x400>;
+				u-boot {
+					cbfs-type = "raw";
+				};
+				u-boot-dtb {
+					cbfs-type = "raw";
+					cbfs-compress = "lzma";
+					cbfs-offset = <0x80>;
+				};
+			};
+			u-boot-dtb {
+				compress = "lz4";
+			};
+		};
+		fdtmap {
+		};
+		image-header {
+			location = "end";
+		};
+	};
+};

tools/patman/tools.py

···
 import glob
 import os
 import shutil
+import struct
 import sys
 import tempfile
 
···
         return string.encode('utf-8')
     return string
 
-def Compress(indata, algo):
+def Compress(indata, algo, with_header=True):
     """Compress some data using a given algorithm
 
     Note that for lzma this uses an old version of the algorithm, not that
···
         data = Run('gzip', '-c', fname, binary=True)
     else:
         raise ValueError("Unknown algorithm '%s'" % algo)
+    if with_header:
+        hdr = struct.pack('<I', len(data))
+        data = hdr + data
     return data
 
-def Decompress(indata, algo):
+def Decompress(indata, algo, with_header=True):
     """Decompress some data using a given algorithm
 
     Note that for lzma this uses an old version of the algorithm, not that
···
     """
     if algo == 'none':
         return indata
+    if with_header:
+        data_len = struct.unpack('<I', indata[:4])[0]
+        indata = indata[4:4 + data_len]
     fname = GetOutputFilename('%s.decomp.tmp' % algo)
     with open(fname, 'wb') as fd:
         fd.write(indata)