At present if this function tries to update the contents such that the
size changes, it raises an error. We plan to add the ability to change
the size of entries after packing is completed, since in some cases it is
not possible to determine the size in advance.
An example of this is with a compressed device tree, where the values
of the device tree change in SetCalculatedProperties() or
ProcessEntryContents(). While the device tree itself does not change size,
since placeholders for any new properties have already bee added by
AddMissingProperties(), we cannot predict the size of the device tree
after compression. If a value changes from 0 to 0x1234 (say), then the
compressed device tree may expand.
As a first step towards supporting this, make ProcessContentsUpdate()
return a value indicating whether the content size is OK. For now this is
always True (since otherwise binman raises an error), but later patches
will adjust this.
Signed-off-by: Simon Glass <sjg@chromium.org>
SetContents() should only be called to set the contents of an entry from
within the ObtainContents() call, since it has no guard against increasing
the size of the contents, thus triggering incorrect operation.
Change all such calls to use ProcessUpdateContents() instead.
Signed-off-by: Simon Glass <sjg@chromium.org>
It is useful to be able to quickly locate the FDT map in the image. An
easy way to do this is with a pointer at the start or end of the image.
Add an 'image header' entry, which places a magic number followed by a
pointer to the FDT map. This can be located at the start or end of the
image, or at a chosen location.
As part of this, update GetSiblingImagePos() to detect missing siblings.
Signed-off-by: Simon Glass <sjg@chromium.org>
