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 <sjg@chromium.org>

1 files changed, 27 insertions, 1 deletions

diff --git a/tools/binman/ftest.py b/tools/binman/ftest.py
index d1ecd65c2c..04bd9f886c 100644
--- a/tools/binman/ftest.py
+++ b/tools/binman/ftest.py
@@ -2485,7 +2485,7 @@ class TestFunctional(unittest.TestCase):
     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):
@@ -2984,6 +2984,32 @@ class TestFunctional(unittest.TestCase):
         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__":
     unittest.main()