tools/fs_config/fs_config_generator.py

#!/usr/bin/env python

import ConfigParser
import re
import sys


GENERATED = '''
/*
 * THIS IS AN AUTOGENERATED FILE! DO NOT MODIFY
 */
'''

INCLUDE = '#include <private/android_filesystem_config.h>'

DEFINE_NO_DIRS = '#define NO_ANDROID_FILESYSTEM_CONFIG_DEVICE_DIRS\n'
DEFINE_NO_FILES = '#define NO_ANDROID_FILESYSTEM_CONFIG_DEVICE_FILES\n'

DEFAULT_WARNING = '#warning No device-supplied android_filesystem_config.h, using empty default.'

NO_ANDROID_FILESYSTEM_CONFIG_DEVICE_DIRS_ENTRY = '{ 00000, AID_ROOT,      AID_ROOT,      0, "system/etc/fs_config_dirs" },'
NO_ANDROID_FILESYSTEM_CONFIG_DEVICE_FILES_ENTRY = '{ 00000, AID_ROOT,      AID_ROOT,      0, "system/etc/fs_config_files" },'

IFDEF_ANDROID_FILESYSTEM_CONFIG_DEVICE_DIRS = '#ifdef NO_ANDROID_FILESYSTEM_CONFIG_DEVICE_DIRS'
ENDIF = '#endif'

OPEN_FILE_STRUCT = 'static const struct fs_path_config android_device_files[] = {'
OPEN_DIR_STRUCT = 'static const struct fs_path_config android_device_dirs[] = {'
CLOSE_FILE_STRUCT = '};'

GENERIC_DEFINE = "#define %s\t%s"

FILE_COMMENT = '// Defined in file: \"%s\"'

# from system/core/include/private/android_filesystem_config.h
AID_OEM_RESERVED_RANGES = [
    (2900, 2999),
    (5000, 5999),
]


AID_MATCH = re.compile('AID_[a-zA-Z]+')

def handle_aid(file_name, section_name, config, aids, seen_aids):
    value = config.get(section_name, 'value')

    errmsg = '%s for: \"' + section_name + '" file: \"' + file_name + '\"'

    if not value:
        raise Exception(errmsg % 'Found specified but unset "value"')

    v = convert_int(value)
    if not v:
        raise Exception(errmsg % ('Invalid "value", not a number, got: \"%s\"' % value))

    # Values must be within OEM range
    if not any(lower <= v <= upper for (lower, upper) in AID_OEM_RESERVED_RANGES):
        s = '"value" not in valid range %s, got: %s'
        s = s % (str(AID_OEM_RESERVED_RANGES), value)
        raise Exception(errmsg % s)

    # use the normalized int value in the dict and detect
    # duplicate definitions of the same vallue
    v = str(v)
    if v in seen_aids[1]:
        # map of value to aid name
        a = seen_aids[1][v]

        # aid name to file
        f = seen_aids[0][a]

        s = 'Duplicate AID value "%s" found on AID: "%s".' % (value, seen_aids[1][v])
        s += ' Previous found in file: "%s."' % f
        raise Exception(errmsg % s)

    seen_aids[1][v] = section_name

    # Append a tuple of (AID_*, base10(value), str(value))
    # We keep the str version of value so we can print that out in the
    # generated header so investigating parties can identify parts.
    # We store the base10 value for sorting, so everything is ascending
    # later.
    aids.append((file_name, section_name, v, value))

def convert_int(num):

        try:
            if num.startswith('0x'):
                return int(num, 16)
            elif num.startswith('0b'):
                return int(num, 2)
            elif num.startswith('0'):
                return int(num, 8)
            else:
                return int(num, 10)
        except ValueError:
            pass
        return None

def handle_path(file_name, section_name, config, files, dirs):

            mode = config.get(section_name, 'mode')
            user = config.get(section_name, 'user')
            group = config.get(section_name, 'group')
            caps = config.get(section_name, 'caps')

            errmsg = 'Found specified but unset option: \"%s" in file: \"' + file_name + '\"'

            if not mode:
                raise Exception(errmsg % 'mode')

            if not user:
                raise Exception(errmsg % 'user')

            if not group:
                raise Exception(errmsg % 'group')

            if not caps:
                raise Exception(errmsg % 'caps')

            caps = caps.split()

            tmp = []
            for x in caps:
                if convert_int(x):
                    tmp.append('(' + x + ')')
                else:
                    tmp.append('(1ULL << CAP_' + x.upper() + ')')

            caps = tmp

            path = '"' + section_name + '"'

            if len(mode) == 3:
                mode = '0' + mode

            try:
                int(mode, 8)
            except:
                raise Exception('Mode must be octal characters, got: "' + mode + '"')

            if len(mode) != 4:
                raise Exception('Mode must be 3 or 4 characters, got: "' + mode + '"')


            caps = '|'.join(caps)

            x = [ mode, user, group, caps, section_name ]
            if section_name[-1] == '/':
                dirs.append((file_name, x))
            else:
                files.append((file_name, x))

def handle_dup(name, file_name, section_name, seen):
        if section_name in seen:
            dups = '"' + seen[section_name] + '" and '
            dups += file_name
            raise Exception('Duplicate ' + name + ' "' + section_name + '" found in files: ' + dups)

def parse(file_name, files, dirs, aids, seen_paths, seen_aids):

        config = ConfigParser.ConfigParser()
        config.read(file_name)

        for s in config.sections():

            if AID_MATCH.match(s) and config.has_option(s, 'value'):
                handle_dup('AID', file_name, s, seen_aids[0])
                seen_aids[0][s] = file_name
                handle_aid(file_name, s, config, aids, seen_aids)
            else:
                handle_dup('path', file_name, s, seen_paths)
                seen_paths[s] = file_name
                handle_path(file_name, s, config, files, dirs)

def generate(files, dirs, aids):
    print GENERATED
    print INCLUDE
    print

    are_dirs = len(dirs) > 0
    are_files = len(files) > 0
    are_aids = len(aids) > 0

    if are_aids:
        for a in aids:
            # use the preserved str value
            print FILE_COMMENT % a[0]
            print GENERIC_DEFINE % (a[1], a[2])

        print

    if not are_dirs:
        print DEFINE_NO_DIRS

    if not are_files:
        print DEFINE_NO_FILES

    if not are_files and not are_dirs and not are_aids:
        print DEFAULT_WARNING
        return

    if are_files:
        print OPEN_FILE_STRUCT
        for tup in files:
            f = tup[0]
            c = tup[1]
            c[4] = '"' + c[4] + '"'
            c = '{ ' + '    ,'.join(c) + ' },'
            print FILE_COMMENT % f
            print '    ' + c

        if not are_dirs:
            print IFDEF_ANDROID_FILESYSTEM_CONFIG_DEVICE_DIRS
            print '    ' + NO_ANDROID_FILESYSTEM_CONFIG_DEVICE_DIRS_ENTRY
            print ENDIF
        print CLOSE_FILE_STRUCT

    if are_dirs:
        print OPEN_DIR_STRUCT
        for d in dirs:
            f[4] = '"' + f[4] + '"'
            d = '{ ' + '    ,'.join(d) + ' },'
            print '    ' + d

        print CLOSE_FILE_STRUCT

def file_key(x):

    # Wrapper class for custom prefix matching strings
    class S(object):
        def __init__(self, str):

            self.orig = str
            self.is_prefix = str[-1] == '*'
            if self.is_prefix:
                self.str = str[:-1]
            else:
                self.str = str

        def __lt__(self, other):

            # if were both suffixed the smallest string
            # is 'bigger'
            if self.is_prefix and other.is_prefix:
                b = len(self.str) > len(other.str)
            # If I am an the suffix match, im bigger
            elif self.is_prefix:
                b = False
            # If other is the suffix match, he's bigger
            elif other.is_prefix:
                b = True
            # Alphabetical
            else:
                b = self.str < other.str
            return b

    return S(x[4])

def main():

    files = []
    dirs = []
    aids = []
    seen_paths = {}

    # (name to file, value to aid)
    seen_aids = ({}, {})

    for x in sys.argv[1:]:
        parse(x, files, dirs, aids, seen_paths, seen_aids)

    # sort entries:
    # * specified path before prefix match
    # ** ie foo before f*
    # * lexicographical less than before other
    # ** ie boo before foo
    # Given these paths:
    # paths=['ac', 'a', 'acd', 'an', 'a*', 'aa', 'ac*']
    # The sort order would be:
    # paths=['a', 'aa', 'ac', 'acd', 'an', 'ac*', 'a*']
    # Thus the fs_config tools will match on specified paths before attempting
    # prefix, and match on the longest matching prefix.
    files.sort(key= lambda x: file_key(x[1]))

    # sort on value of (file_name, name, value, strvalue)
    # This is only cosmetic so AIDS are arranged in ascending order
    # within the generated file.
    aids.sort(key=lambda x: x[2])

    generate(files, dirs, aids)

if __name__ == '__main__':
    main()