Add feature to generate config for kernel

[metaspace]

Add config subcommand to generate a kernel config from a set of fragments like the ones in here.

The generated config should include configuration to boot the vm with the configured debian features.

The command should check that all requested config items are set accordingly similar to this:

#!/usr/bin/env python3

import argparse
import re
import sys
from itertools import combinations

parser = argparse.ArgumentParser()
parser.add_argument("--config", type=argparse.FileType('rt'))
parser.add_argument("fragments", metavar='FRAGMENT', type=argparse.FileType('rt'), nargs="+")

args = parser.parse_args()

input_fragments = dict()
output_configs = dict()
matcher = re.compile(r"""^(CONFIG_\w+)=([nym])""")

def get_configs(file):
    configs = dict()
    for line in file.readlines():
        matches = matcher.match(line)
        if matches:
            configs[matches.group(1)] = matches.group(2)
    return configs

for fragment in args.fragments:
    input_fragments[fragment.name] = get_configs(fragment)

ok = True

for (key_a, key_b) in combinations(input_fragments.keys(), 2):
    fragment_a = input_fragments[key_a]
    fragment_b = input_fragments[key_b]

    common_configs = set(fragment_a.keys()).intersection(set(fragment_b.keys()))

    for config in common_configs:
        value_a = fragment_a[config]
        value_b = fragment_b[config]
        if value_a != value_b:
            print(f"ERROR: {config} has conflicting values {key_a}:{value_a} and {key_b}:{value_b}")
            ok = False

output_configs |= get_configs(args.config)


input_configs = dict()

for fragment_name,configs in input_fragments.items():
    input_configs |= configs

for key,value in input_configs.items():
    check_failed = \
        (value != 'n' \
         and output_configs.get(key) != value) or \
        (value == 'n' \
         and key in output_configs and output_configs.get(key) != value)
    if check_failed:
        ok = False
        print(f"ERROR: {key}={value}")

if not ok:
    sys.exit(-1)

[metaspace]

Maybe do something semantically like this:

    #!/bin/bash
    set -e
    set -x
    rm -f {{path}}-build/.config
    version="$({{path}}/scripts/min-tool-version.sh bindgen)"
    export PATH="{{top}}/bindgen-$version/bin:$PATH"
    (cd {{path}} && make -j $(nproc) O={{top}}/{{path}}-build LLVM=1 \
      allnoconfig)
      {{path}}/scripts/kconfig/merge_config.sh -m -O {{path}}-build {{path}}-build/.config \
      config/default.fragment \
      `echo "{{FRAGMENTS}}" | sed -E 's#([^[:space:]]+)#config/\1.fragment#g'`
      (cd {{path}} && make -j $(nproc) O={{top}}/{{path}}-build LLVM=1 \
      olddefconfig)
    ./config-test.py --config {{path}}-build/.config config/default.fragment `echo "{{FRAGMENTS}}" | sed -E 's#([^[:space:]]+)#config/\1.fragment#g'`

[metaspace]

Or use scripts/config