bsection.py

# SPDX-License-Identifier: GPL-2.0+
# Copyright (c) 2018 Google, Inc
# Written by Simon Glass <sjg@chromium.org>
#
# Base class for sections (collections of entries)
#

from __future__ import print_function

from collections import OrderedDict
import sys

from entry import Entry
import fdt_util
import re
import state
import tools

class Section(object):
    """A section which contains multiple entries

    A section represents a collection of entries. There must be one or more
    sections in an image. Sections are used to group entries together.

    Attributes:
        _node: Node object that contains the section definition in device tree
        _parent_section: Parent Section object which created this Section
        _size: Section size in bytes, or None if not known yet
        _align_size: Section size alignment, or None
        _pad_before: Number of bytes before the first entry starts. This
            effectively changes the place where entry offset 0 starts
        _pad_after: Number of bytes after the last entry ends. The last
            entry will finish on or before this boundary
        _pad_byte: Byte to use to pad the section where there is no entry
        _sort: True if entries should be sorted by offset, False if they
            must be in-order in the device tree description
        _skip_at_start: Number of bytes before the first entry starts. These
            effectively adjust the starting offset of entries. For example,
            if _pad_before is 16, then the first entry would start at 16.
            An entry with offset = 20 would in fact be written at offset 4
            in the image file.
        _end_4gb: Indicates that the section ends at the 4GB boundary. This is
            used for x86 images, which want to use offsets such that a memory
            address (like 0xff800000) is the first entry offset. This causes
            _skip_at_start to be set to the starting memory address.
        _name_prefix: Prefix to add to the name of all entries within this
            section
        _entries: OrderedDict() of entries
        _orig_offset: Original offset value read from node
        _orig_size: Original size value read from node
    """
    def __init__(self, name, parent_section, node, image, test=False):
        global entry
        global Entry
        import entry
        from entry import Entry

        self._parent_section = parent_section
        self._name = name
        self._node = node
        self._image = image
        self._offset = None
        self._size = None
        self._align_size = None
        self._pad_before = 0
        self._pad_after = 0
        self._pad_byte = 0
        self._sort = False
        self._skip_at_start = None
        self._end_4gb = False
        self._name_prefix = ''
        self._entries = OrderedDict()
        self._image_pos = None
        if not test:
            self._ReadNode()
            self._ReadEntries()

    def _ReadNode(self):
        """Read properties from the section node"""
        self._offset = fdt_util.GetInt(self._node, 'offset')
        self._size = fdt_util.GetInt(self._node, 'size')
        self._orig_offset = self._offset
        self._orig_size = self._size
        self._align_size = fdt_util.GetInt(self._node, 'align-size')
        if tools.NotPowerOfTwo(self._align_size):
            self._Raise("Alignment size %s must be a power of two" %
                        self._align_size)
        self._pad_before = fdt_util.GetInt(self._node, 'pad-before', 0)
        self._pad_after = fdt_util.GetInt(self._node, 'pad-after', 0)
        self._pad_byte = fdt_util.GetInt(self._node, 'pad-byte', 0)
        self._sort = fdt_util.GetBool(self._node, 'sort-by-offset')
        self._end_4gb = fdt_util.GetBool(self._node, 'end-at-4gb')
        self._skip_at_start = fdt_util.GetInt(self._node, 'skip-at-start')
        if self._end_4gb:
            if not self._size:
                self._Raise("Section size must be provided when using end-at-4gb")
            if self._skip_at_start is not None:
                self._Raise("Provide either 'end-at-4gb' or 'skip-at-start'")
            else:
                self._skip_at_start = 0x100000000 - self._size
        else:
            if self._skip_at_start is None:
                self._skip_at_start = 0
        self._name_prefix = fdt_util.GetString(self._node, 'name-prefix')

    def _ReadEntries(self):
        for node in self._node.subnodes:
            if node.name == 'hash':
                continue
            entry = Entry.Create(self, node)
            entry.SetPrefix(self._name_prefix)
            self._entries[node.name] = entry

    def GetFdtSet(self):
        """Get the set of device tree files used by this image"""
        fdt_set = set()
        for entry in self._entries.values():
            fdt_set.update(entry.GetFdtSet())
        return fdt_set

    def SetOffset(self, offset):
        self._offset = offset

    def ExpandEntries(self):
        for entry in self._entries.values():
            entry.ExpandEntries()

    def AddMissingProperties(self):
        """Add new properties to the device tree as needed for this entry"""
        for prop in ['offset', 'size', 'image-pos']:
            if not prop in self._node.props:
                state.AddZeroProp(self._node, prop)
        state.CheckAddHashProp(self._node)
        for entry in self._entries.values():
            entry.AddMissingProperties()

    def SetCalculatedProperties(self):
        state.SetInt(self._node, 'offset', self._offset or 0)
        state.SetInt(self._node, 'size', self._size)
        image_pos = self._image_pos
        if self._parent_section:
            image_pos -= self._parent_section.GetRootSkipAtStart()
        state.SetInt(self._node, 'image-pos', image_pos)
        for entry in self._entries.values():
            entry.SetCalculatedProperties()

    def ProcessFdt(self, fdt):
        todo = self._entries.values()
        for passnum in range(3):
            next_todo = []
            for entry in todo:
                if not entry.ProcessFdt(fdt):
                    next_todo.append(entry)
            todo = next_todo
            if not todo:
                break
        if todo:
            self._Raise('Internal error: Could not complete processing of Fdt: '
                        'remaining %s' % todo)
        return True

    def CheckSize(self):
        """Check that the section contents does not exceed its size, etc."""
        contents_size = 0
        for entry in self._entries.values():
            contents_size = max(contents_size, entry.offset + entry.size)

        contents_size -= self._skip_at_start

        size = self._size
        if not size:
            size = self._pad_before + contents_size + self._pad_after
            size = tools.Align(size, self._align_size)

        if self._size and contents_size > self._size:
            self._Raise("contents size %#x (%d) exceeds section size %#x (%d)" %
                       (contents_size, contents_size, self._size, self._size))
        if not self._size:
            self._size = size
        if self._size != tools.Align(self._size, self._align_size):
            self._Raise("Size %#x (%d) does not match align-size %#x (%d)" %
                  (self._size, self._size, self._align_size, self._align_size))
        return size

    def _Raise(self, msg):
        """Raises an error for this section

        Args:
            msg: Error message to use in the raise string
        Raises:
            ValueError()
        """
        raise ValueError("Section '%s': %s" % (self._node.path, msg))

    def GetPath(self):
        """Get the path of an image (in the FDT)

        Returns:
            Full path of the node for this image
        """
        return self._node.path

    def FindEntryType(self, etype):
        """Find an entry type in the section

        Args:
            etype: Entry type to find
        Returns:
            entry matching that type, or None if not found
        """
        for entry in self._entries.values():
            if entry.etype == etype:
                return entry
        return None

    def GetEntryContents(self):
        """Call ObtainContents() for each entry

        This calls each entry's ObtainContents() a few times until they all
        return True. We stop calling an entry's function once it returns
        True. This allows the contents of one entry to depend on another.

        After 3 rounds we give up since it's likely an error.
        """
        todo = self._entries.values()
        for passnum in range(3):
            next_todo = []
            for entry in todo:
                if not entry.ObtainContents():
                    next_todo.append(entry)
            todo = next_todo
            if not todo:
                break
        if todo:
            self._Raise('Internal error: Could not complete processing of '
                        'contents: remaining %s' % todo)
        return True

    def _SetEntryOffsetSize(self, name, offset, size):
        """Set the offset and size of an entry

        Args:
            name: Entry name to update
            offset: New offset, or None to leave alone
            size: New size, or None to leave alone
        """
        entry = self._entries.get(name)
        if not entry:
            self._Raise("Unable to set offset/size for unknown entry '%s'" %
                        name)
        entry.SetOffsetSize(self._skip_at_start + offset if offset else None,
                            size)

    def GetEntryOffsets(self):
        """Handle entries that want to set the offset/size of other entries

        This calls each entry's GetOffsets() method. If it returns a list
        of entries to update, it updates them.
        """
        for entry in self._entries.values():
            offset_dict = entry.GetOffsets()
            for name, info in offset_dict.items():
                self._SetEntryOffsetSize(name, *info)

    def ResetForPack(self):
        """Reset offset/size fields so that packing can be done again"""
        self._offset = self._orig_offset
        self._size = self._orig_size
        for entry in self._entries.values():
            entry.ResetForPack()

    def PackEntries(self):
        """Pack all entries into the section"""
        offset = self._skip_at_start
        for entry in self._entries.values():
            offset = entry.Pack(offset)
        self._size = self.CheckSize()

    def _SortEntries(self):
        """Sort entries by offset"""
        entries = sorted(self._entries.values(), key=lambda entry: entry.offset)
        self._entries.clear()
        for entry in entries:
            self._entries[entry._node.name] = entry

    def _ExpandEntries(self):
        """Expand any entries that are permitted to"""
        exp_entry = None
        for entry in self._entries.values():
            if exp_entry:
                exp_entry.ExpandToLimit(entry.offset)
                exp_entry = None
            if entry.expand_size:
                exp_entry = entry
        if exp_entry:
            exp_entry.ExpandToLimit(self._size)

    def CheckEntries(self):
        """Check that entries do not overlap or extend outside the section

        This also sorts entries, if needed and expands
        """
        if self._sort:
            self._SortEntries()
        self._ExpandEntries()
        offset = 0
        prev_name = 'None'
        for entry in self._entries.values():
            entry.CheckOffset()
            if (entry.offset < self._skip_at_start or
                entry.offset + entry.size > self._skip_at_start + self._size):
                entry.Raise("Offset %#x (%d) is outside the section starting "
                            "at %#x (%d)" %
                            (entry.offset, entry.offset, self._skip_at_start,
                             self._skip_at_start))
            if entry.offset < offset:
                entry.Raise("Offset %#x (%d) overlaps with previous entry '%s' "
                            "ending at %#x (%d)" %
                            (entry.offset, entry.offset, prev_name, offset, offset))
            offset = entry.offset + entry.size
            prev_name = entry.GetPath()

    def SetImagePos(self, image_pos):
        self._image_pos = image_pos
        for entry in self._entries.values():
            entry.SetImagePos(image_pos)

    def ProcessEntryContents(self):
        """Call the ProcessContents() method for each entry

        This is intended to adjust the contents as needed by the entry type.

        Returns:
            True if no entries needed to change their size
        """
        sizes_ok = True
        for entry in self._entries.values():
            if not entry.ProcessContents():
                sizes_ok = False
                print("Entry '%s' size change" % self._node.path)
        return sizes_ok

    def WriteSymbols(self):
        """Write symbol values into binary files for access at run time"""
        for entry in self._entries.values():
            entry.WriteSymbols(self)

    def BuildSection(self, fd, base_offset):
        """Write the section to a file"""
        fd.seek(base_offset)
        fd.write(self.GetData())

    def GetData(self):
        """Get the contents of the section"""
        section_data = tools.GetBytes(self._pad_byte, self._size)

        for entry in self._entries.values():
            data = entry.GetData()
            base = self._pad_before + entry.offset - self._skip_at_start
            section_data = (section_data[:base] + data +
                            section_data[base + len(data):])
        return section_data

    def LookupSymbol(self, sym_name, optional, msg):
        """Look up a symbol in an ELF file

        Looks up a symbol in an ELF file. Only entry types which come from an
        ELF image can be used by this function.

        At present the only entry property supported is offset.

        Args:
            sym_name: Symbol name in the ELF file to look up in the format
                _binman_<entry>_prop_<property> where <entry> is the name of
                the entry and <property> is the property to find (e.g.
                _binman_u_boot_prop_offset). As a special case, you can append
                _any to <entry> to have it search for any matching entry. E.g.
                _binman_u_boot_any_prop_offset will match entries called u-boot,
                u-boot-img and u-boot-nodtb)
            optional: True if the symbol is optional. If False this function
                will raise if the symbol is not found
            msg: Message to display if an error occurs

        Returns:
            Value that should be assigned to that symbol, or None if it was
                optional and not found

        Raises:
            ValueError if the symbol is invalid or not found, or references a
                property which is not supported
        """
        m = re.match(r'^_binman_(\w+)_prop_(\w+)$', sym_name)
        if not m:
            raise ValueError("%s: Symbol '%s' has invalid format" %
                             (msg, sym_name))
        entry_name, prop_name = m.groups()
        entry_name = entry_name.replace('_', '-')
        entry = self._entries.get(entry_name)
        if not entry:
            if entry_name.endswith('-any'):
                root = entry_name[:-4]
                for name in self._entries:
                    if name.startswith(root):
                        rest = name[len(root):]
                        if rest in ['', '-img', '-nodtb']:
                            entry = self._entries[name]
        if not entry:
            err = ("%s: Entry '%s' not found in list (%s)" %
                   (msg, entry_name, ','.join(self._entries.keys())))
            if optional:
                print('Warning: %s' % err, file=sys.stderr)
                return None
            raise ValueError(err)
        if prop_name == 'offset':
            return entry.offset
        elif prop_name == 'image_pos':
            return entry.image_pos
        else:
            raise ValueError("%s: No such property '%s'" % (msg, prop_name))

    def GetEntries(self):
        """Get the dict of entries in a section

        Returns:
            OrderedDict of entries in a section
        """
        return self._entries

    def GetSize(self):
        """Get the size of a section in bytes

        This is only meaningful if the section has a pre-defined size, or the
        entries within it have been packed, so that the size has been
        calculated.

        Returns:
            Entry size in bytes
        """
        return self._size

    def WriteMap(self, fd, indent):
        """Write a map of the section to a .map file

        Args:
            fd: File to write the map to
        """
        Entry.WriteMapLine(fd, indent, self._name, self._offset or 0,
                           self._size, self._image_pos)
        for entry in self._entries.values():
            entry.WriteMap(fd, indent + 1)

    def GetContentsByPhandle(self, phandle, source_entry):
        """Get the data contents of an entry specified by a phandle

        This uses a phandle to look up a node and and find the entry
        associated with it. Then it returnst he contents of that entry.

        Args:
            phandle: Phandle to look up (integer)
            source_entry: Entry containing that phandle (used for error
                reporting)

        Returns:
            data from associated entry (as a string), or None if not found
        """
        node = self._node.GetFdt().LookupPhandle(phandle)
        if not node:
            source_entry.Raise("Cannot find node for phandle %d" % phandle)
        for entry in self._entries.values():
            if entry._node == node:
                return entry.GetData()
        source_entry.Raise("Cannot find entry for node '%s'" % node.name)

    def ExpandSize(self, size):
        """Change the size of an entry

        Args:
            size: New size for entry
        """
        if size != self._size:
            self._size = size

    def GetRootSkipAtStart(self):
        """Get the skip-at-start value for the top-level section

        This is used to find out the starting offset for root section that
        contains this section. If this is a top-level section then it returns
        the skip-at-start offset for this section.

        This is used to get the absolute position of section within the image.

        Returns:
            Integer skip-at-start value for the root section containing this
                section
        """
        if self._parent_section:
            return self._parent_section.GetRootSkipAtStart()
        return self._skip_at_start

    def GetStartOffset(self):
        """Get the start offset for this section

        Returns:
            The first available offset in this section (typically 0)
        """
        return self._skip_at_start

    def GetImageSize(self):
        """Get the size of the image containing this section

        Returns:
            Image size as an integer number of bytes, which may be None if the
                image size is dynamic and its sections have not yet been packed
        """
        return self._image._size

    def ListEntries(self, entries, indent):
        """Override this method to list all files in the section"""
        Entry.AddEntryInfo(entries, indent, self._name, 'section', self._size,
                           self._image_pos, None, self._offset,
                           self._parent_section)
        for entry in self._entries.values():
            entry.ListEntries(entries, indent + 1)