# SPDX-License-Identifier: GPL-2.0+
# Copyright 2018 Google, Inc
# Written by Simon Glass <sjg@chromium.org>
#
# Holds and modifies the state information held by binman
#

import hashlib
import re

import os
import tools

# Records the device-tree files known to binman, keyed by filename (e.g.
# 'u-boot-spl.dtb')
fdt_files = {}

# Arguments passed to binman to provide arguments to entries
entry_args = {}

# True to use fake device-tree files for testing (see U_BOOT_DTB_DATA in
# ftest.py)
use_fake_dtb = False

# Set of all device tree files references by images
fdt_set = set()

# Same as above, but excluding the main one
fdt_subset = set()

# The DTB which contains the full image information
main_dtb = None

# Allow entries to expand after they have been packed. This is detected and
# forces a re-pack. If not allowed, any attempted expansion causes an error in
# Entry.ProcessContentsUpdate()
allow_entry_expansion = True

def GetFdt(fname):
    """Get the Fdt object for a particular device-tree filename

    Binman keeps track of at least one device-tree file called u-boot.dtb but
    can also have others (e.g. for SPL). This function looks up the given
    filename and returns the associated Fdt object.

    Args:
        fname: Filename to look up (e.g. 'u-boot.dtb').

    Returns:
        Fdt object associated with the filename
    """
    return fdt_files[fname]

def GetFdtPath(fname):
    """Get the full pathname of a particular Fdt object

    Similar to GetFdt() but returns the pathname associated with the Fdt.

    Args:
        fname: Filename to look up (e.g. 'u-boot.dtb').

    Returns:
        Full path name to the associated Fdt
    """
    return fdt_files[fname]._fname

def GetFdtContents(fname='u-boot.dtb'):
    """Looks up the FDT pathname and contents

    This is used to obtain the Fdt pathname and contents when needed by an
    entry. It supports a 'fake' dtb, allowing tests to substitute test data for
    the real dtb.

    Args:
        fname: Filename to look up (e.g. 'u-boot.dtb').

    Returns:
        tuple:
            pathname to Fdt
            Fdt data (as bytes)
    """
    if fname in fdt_files and not use_fake_dtb:
        pathname = GetFdtPath(fname)
        data = GetFdt(fname).GetContents()
    else:
        pathname = tools.GetInputFilename(fname)
        data = tools.ReadFile(pathname)
    return pathname, data

def SetEntryArgs(args):
    """Set the value of the entry args

    This sets up the entry_args dict which is used to supply entry arguments to
    entries.

    Args:
        args: List of entry arguments, each in the format "name=value"
    """
    global entry_args

    entry_args = {}
    if args:
        for arg in args:
            m = re.match('([^=]*)=(.*)', arg)
            if not m:
                raise ValueError("Invalid entry arguemnt '%s'" % arg)
            entry_args[m.group(1)] = m.group(2)

def GetEntryArg(name):
    """Get the value of an entry argument

    Args:
        name: Name of argument to retrieve

    Returns:
        String value of argument
    """
    return entry_args.get(name)

def Prepare(images, dtb):
    """Get device tree files ready for use

    This sets up a set of device tree files that can be retrieved by GetFdts().
    At present there is only one, that for U-Boot proper.

    Args:
        images: List of images being used
        dtb: Main dtb
    """
    global fdt_set, fdt_subset, fdt_files, main_dtb
    # Import these here in case libfdt.py is not available, in which case
    # the above help option still works.
    import fdt
    import fdt_util

    # If we are updating the DTBs we need to put these updated versions
    # where Entry_blob_dtb can find them. We can ignore 'u-boot.dtb'
    # since it is assumed to be the one passed in with options.dt, and
    # was handled just above.
    main_dtb = dtb
    fdt_files.clear()
    fdt_files['u-boot.dtb'] = dtb
    fdt_subset = set()
    if not use_fake_dtb:
        for image in images.values():
            fdt_subset.update(image.GetFdtSet())
        fdt_subset.discard('u-boot.dtb')
        for other_fname in fdt_subset:
            infile = tools.GetInputFilename(other_fname)
            other_fname_dtb = fdt_util.EnsureCompiled(infile)
            out_fname = tools.GetOutputFilename('%s.out' %
                    os.path.split(other_fname)[1])
            tools.WriteFile(out_fname, tools.ReadFile(other_fname_dtb))
            other_dtb = fdt.FdtScan(out_fname)
            fdt_files[other_fname] = other_dtb

def GetFdts():
    """Yield all device tree files being used by binman

    Yields:
        Device trees being used (U-Boot proper, SPL, TPL)
    """
    yield main_dtb
    for other_fname in fdt_subset:
        yield fdt_files[other_fname]

def GetUpdateNodes(node):
    """Yield all the nodes that need to be updated in all device trees

    The property referenced by this node is added to any device trees which
    have the given node. Due to removable of unwanted notes, SPL and TPL may
    not have this node.

    Args:
        node: Node object in the main device tree to look up

    Yields:
        Node objects in each device tree that is in use (U-Boot proper, which
            is node, SPL and TPL)
    """
    yield node
    for dtb in fdt_files.values():
        if dtb != node.GetFdt():
            other_node = dtb.GetNode(node.path)
            if other_node:
                yield other_node

def AddZeroProp(node, prop):
    """Add a new property to affected device trees with an integer value of 0.

    Args:
        prop_name: Name of property
    """
    for n in GetUpdateNodes(node):
        n.AddZeroProp(prop)

def AddSubnode(node, name):
    """Add a new subnode to a node in affected device trees

    Args:
        node: Node to add to
        name: name of node to add

    Returns:
        New subnode that was created in main tree
    """
    first = None
    for n in GetUpdateNodes(node):
        subnode = n.AddSubnode(name)
        if not first:
            first = subnode
    return first

def AddString(node, prop, value):
    """Add a new string property to affected device trees

    Args:
        prop_name: Name of property
        value: String value (which will be \0-terminated in the DT)
    """
    for n in GetUpdateNodes(node):
        n.AddString(prop, value)

def SetInt(node, prop, value):
    """Update an integer property in affected device trees with an integer value

    This is not allowed to change the size of the FDT.

    Args:
        prop_name: Name of property
    """
    for n in GetUpdateNodes(node):
        n.SetInt(prop, value)

def CheckAddHashProp(node):
    hash_node = node.FindNode('hash')
    if hash_node:
        algo = hash_node.props.get('algo')
        if not algo:
            return "Missing 'algo' property for hash node"
        if algo.value == 'sha256':
            size = 32
        else:
            return "Unknown hash algorithm '%s'" % algo
        for n in GetUpdateNodes(hash_node):
            n.AddEmptyProp('value', size)

def CheckSetHashValue(node, get_data_func):
    hash_node = node.FindNode('hash')
    if hash_node:
        algo = hash_node.props.get('algo').value
        if algo == 'sha256':
            m = hashlib.sha256()
            m.update(get_data_func())
            data = m.digest()
        for n in GetUpdateNodes(hash_node):
            n.SetData('value', data)

def SetAllowEntryExpansion(allow):
    """Set whether post-pack expansion of entries is allowed

    Args:
       allow: True to allow expansion, False to raise an exception
    """
    global allow_entry_expansion

    allow_entry_expansion = allow

def AllowEntryExpansion():
    """Check whether post-pack expansion of entries is allowed

    Returns:
        True if expansion should be allowed, False if an exception should be
            raised
    """
    return allow_entry_expansion