minikconfig: add parser skeleton
This implements a scanner and recursive descent parser for Kconfig-like
configuration files. The only "action" of the parser is for now to
detect undefined variables and process include files.
The main differences between Kconfig and this are:
* only the "bool" type is supported
* variables can only be defined once
* choices are not supported (but they could be added as syntactic
sugar for multiple Boolean values)
* menus and other graphical concepts (prompts, help text) are not
supported
* assignments ("CONFIG_FOO=y", "CONFIG_FOO=n") are parsed as part
of the Kconfig language, not as a separate file.
The idea was originally by Ákos Kovács, but I could not find his
implementation so I had to redo it.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20190123065618.3520-23-yang.zhong@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Paolo Bonzini
parent
28ba6bdd2f
commit
d4fdccadba
441
scripts/minikconf.py
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441
scripts/minikconf.py
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#
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# Mini-Kconfig parser
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#
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# Copyright (c) 2015 Red Hat Inc.
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#
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# Authors:
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# Paolo Bonzini <pbonzini@redhat.com>
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#
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# This work is licensed under the terms of the GNU GPL, version 2
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# or, at your option, any later version. See the COPYING file in
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# the top-level directory.
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from __future__ import print_function
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import os
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import sys
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__all__ = [ 'KconfigParserError', 'KconfigData', 'KconfigParser' ]
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def debug_print(*args):
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#print('# ' + (' '.join(str(x) for x in args)))
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pass
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# -------------------------------------------
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# KconfigData implements the Kconfig semantics. For now it can only
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# detect undefined symbols, i.e. symbols that were referenced in
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# assignments or dependencies but were not declared with "config FOO".
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#
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# Semantic actions are represented by methods called do_*. The do_var
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# method return the semantic value of a variable (which right now is
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# just its name).
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# -------------------------------------------
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class KconfigData:
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def __init__(self):
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self.previously_included = []
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self.incl_info = None
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self.defined_vars = set()
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self.referenced_vars = set()
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# semantic analysis -------------
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def check_undefined(self):
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undef = False
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for i in self.referenced_vars:
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if not (i in self.defined_vars):
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print("undefined symbol %s" % (i), file=sys.stderr)
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undef = True
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return undef
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# semantic actions -------------
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def do_declaration(self, var):
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if (var in self.defined_vars):
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raise Exception('variable "' + var + '" defined twice')
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self.defined_vars.add(var)
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# var is a string with the variable's name.
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#
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# For now this just returns the variable's name itself.
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def do_var(self, var):
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self.referenced_vars.add(var)
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return var
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def do_assignment(self, var, val):
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pass
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def do_default(self, var, val, cond=None):
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pass
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def do_depends_on(self, var, expr):
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pass
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def do_select(self, var, symbol, cond=None):
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pass
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def do_imply(self, var, symbol, cond=None):
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pass
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# -------------------------------------------
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# KconfigParser implements a recursive descent parser for (simplified)
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# Kconfig syntax.
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# -------------------------------------------
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# tokens table
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TOKENS = {}
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TOK_NONE = -1
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TOK_LPAREN = 0; TOKENS[TOK_LPAREN] = '"("';
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TOK_RPAREN = 1; TOKENS[TOK_RPAREN] = '")"';
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TOK_EQUAL = 2; TOKENS[TOK_EQUAL] = '"="';
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TOK_AND = 3; TOKENS[TOK_AND] = '"&&"';
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TOK_OR = 4; TOKENS[TOK_OR] = '"||"';
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TOK_NOT = 5; TOKENS[TOK_NOT] = '"!"';
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TOK_DEPENDS = 6; TOKENS[TOK_DEPENDS] = '"depends"';
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TOK_ON = 7; TOKENS[TOK_ON] = '"on"';
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TOK_SELECT = 8; TOKENS[TOK_SELECT] = '"select"';
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TOK_IMPLY = 9; TOKENS[TOK_IMPLY] = '"imply"';
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TOK_CONFIG = 10; TOKENS[TOK_CONFIG] = '"config"';
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TOK_DEFAULT = 11; TOKENS[TOK_DEFAULT] = '"default"';
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TOK_Y = 12; TOKENS[TOK_Y] = '"y"';
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TOK_N = 13; TOKENS[TOK_N] = '"n"';
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TOK_SOURCE = 14; TOKENS[TOK_SOURCE] = '"source"';
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TOK_BOOL = 15; TOKENS[TOK_BOOL] = '"bool"';
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TOK_IF = 16; TOKENS[TOK_IF] = '"if"';
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TOK_ID = 17; TOKENS[TOK_ID] = 'identifier';
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TOK_EOF = 18; TOKENS[TOK_EOF] = 'end of file';
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class KconfigParserError(Exception):
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def __init__(self, parser, msg, tok=None):
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self.loc = parser.location()
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tok = tok or parser.tok
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if tok != TOK_NONE:
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location = TOKENS.get(tok, None) or ('"%s"' % tok)
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msg = '%s before %s' % (msg, location)
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self.msg = msg
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def __str__(self):
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return "%s: %s" % (self.loc, self.msg)
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class KconfigParser:
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@classmethod
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def parse(self, fp):
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data = KconfigData()
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parser = KconfigParser(data)
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parser.parse_file(fp)
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if data.check_undefined():
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raise KconfigParserError(parser, "there were undefined symbols")
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return data
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def __init__(self, data):
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self.data = data
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def parse_file(self, fp):
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self.abs_fname = os.path.abspath(fp.name)
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self.fname = fp.name
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self.data.previously_included.append(self.abs_fname)
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self.src = fp.read()
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if self.src == '' or self.src[-1] != '\n':
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self.src += '\n'
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self.cursor = 0
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self.line = 1
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self.line_pos = 0
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self.get_token()
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self.parse_config()
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# file management -----
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def error_path(self):
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inf = self.data.incl_info
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res = ""
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while inf:
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res = ("In file included from %s:%d:\n" % (inf['file'],
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inf['line'])) + res
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inf = inf['parent']
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return res
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def location(self):
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col = 1
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for ch in self.src[self.line_pos:self.pos]:
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if ch == '\t':
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col += 8 - ((col - 1) % 8)
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else:
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col += 1
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return '%s%s:%d:%d' %(self.error_path(), self.fname, self.line, col)
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def do_include(self, include):
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incl_abs_fname = os.path.join(os.path.dirname(self.abs_fname),
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include)
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# catch inclusion cycle
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inf = self.data.incl_info
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while inf:
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if incl_abs_fname == os.path.abspath(inf['file']):
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raise KconfigParserError(self, "Inclusion loop for %s"
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% include)
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inf = inf['parent']
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# skip multiple include of the same file
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if incl_abs_fname in self.data.previously_included:
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return
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try:
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fp = open(incl_abs_fname, 'r')
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except IOError as e:
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raise KconfigParserError(self,
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'%s: %s' % (e.strerror, include))
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inf = self.data.incl_info
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self.data.incl_info = { 'file': self.fname, 'line': self.line,
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'parent': inf }
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KconfigParser(self.data).parse_file(fp)
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self.data.incl_info = inf
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# recursive descent parser -----
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# y_or_n: Y | N
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def parse_y_or_n(self):
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if self.tok == TOK_Y:
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self.get_token()
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return True
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if self.tok == TOK_N:
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self.get_token()
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return False
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raise KconfigParserError(self, 'Expected "y" or "n"')
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# var: ID
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def parse_var(self):
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if self.tok == TOK_ID:
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val = self.val
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self.get_token()
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return self.data.do_var(val)
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else:
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raise KconfigParserError(self, 'Expected identifier')
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# assignment_var: ID (starting with "CONFIG_")
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def parse_assignment_var(self):
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if self.tok == TOK_ID:
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val = self.val
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if not val.startswith("CONFIG_"):
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raise KconfigParserError(self,
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'Expected identifier starting with "CONFIG_"', TOK_NONE)
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self.get_token()
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return self.data.do_var(val[7:])
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else:
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raise KconfigParserError(self, 'Expected identifier')
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# assignment: var EQUAL y_or_n
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def parse_assignment(self):
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var = self.parse_assignment_var()
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if self.tok != TOK_EQUAL:
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raise KconfigParserError(self, 'Expected "="')
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self.get_token()
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self.data.do_assignment(var, self.parse_y_or_n())
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# primary: NOT primary
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# | LPAREN expr RPAREN
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# | var
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def parse_primary(self):
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if self.tok == TOK_NOT:
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self.get_token()
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self.parse_primary()
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elif self.tok == TOK_LPAREN:
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self.get_token()
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self.parse_expr()
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if self.tok != TOK_RPAREN:
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raise KconfigParserError(self, 'Expected ")"')
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self.get_token()
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elif self.tok == TOK_ID:
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self.parse_var()
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else:
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raise KconfigParserError(self, 'Expected "!" or "(" or identifier')
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# disj: primary (OR primary)*
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def parse_disj(self):
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self.parse_primary()
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while self.tok == TOK_OR:
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self.get_token()
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self.parse_primary()
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# expr: disj (AND disj)*
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def parse_expr(self):
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self.parse_disj()
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while self.tok == TOK_AND:
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self.get_token()
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self.parse_disj()
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# condition: IF expr
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# | empty
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def parse_condition(self):
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if self.tok == TOK_IF:
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self.get_token()
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return self.parse_expr()
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else:
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return None
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# property: DEFAULT y_or_n condition
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# | DEPENDS ON expr
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# | SELECT var condition
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# | BOOL
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def parse_property(self, var):
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if self.tok == TOK_DEFAULT:
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self.get_token()
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val = self.parse_y_or_n()
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cond = self.parse_condition()
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self.data.do_default(var, val, cond)
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elif self.tok == TOK_DEPENDS:
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self.get_token()
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if self.tok != TOK_ON:
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raise KconfigParserError(self, 'Expected "on"')
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self.get_token()
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self.data.do_depends_on(var, self.parse_expr())
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elif self.tok == TOK_SELECT:
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self.get_token()
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symbol = self.parse_var()
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cond = self.parse_condition()
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self.data.do_select(var, symbol, cond)
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elif self.tok == TOK_IMPLY:
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self.get_token()
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symbol = self.parse_var()
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cond = self.parse_condition()
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self.data.do_imply(var, symbol, cond)
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elif self.tok == TOK_BOOL:
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self.get_token()
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else:
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raise KconfigParserError(self, 'Error in recursive descent?')
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# properties: properties property
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# | /* empty */
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def parse_properties(self, var):
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had_default = False
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while self.tok == TOK_DEFAULT or self.tok == TOK_DEPENDS or \
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self.tok == TOK_SELECT or self.tok == TOK_BOOL or \
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self.tok == TOK_IMPLY:
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self.parse_property(var)
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self.data.do_default(var, False)
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# for nicer error message
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if self.tok != TOK_SOURCE and self.tok != TOK_CONFIG and \
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self.tok != TOK_ID and self.tok != TOK_EOF:
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raise KconfigParserError(self, 'expected "source", "config", identifier, '
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+ '"default", "depends on", "imply" or "select"')
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# declaration: config var properties
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def parse_declaration(self):
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if self.tok == TOK_CONFIG:
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self.get_token()
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var = self.parse_var()
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self.data.do_declaration(var)
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self.parse_properties(var)
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else:
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raise KconfigParserError(self, 'Error in recursive descent?')
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# clause: SOURCE
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# | declaration
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# | assignment
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def parse_clause(self):
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if self.tok == TOK_SOURCE:
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val = self.val
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self.get_token()
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self.do_include(val)
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elif self.tok == TOK_CONFIG:
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self.parse_declaration()
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elif self.tok == TOK_ID:
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self.parse_assignment()
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else:
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raise KconfigParserError(self, 'expected "source", "config" or identifier')
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# config: clause+ EOF
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def parse_config(self):
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while self.tok != TOK_EOF:
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self.parse_clause()
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return self.data
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# scanner -----
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def get_token(self):
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while True:
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self.tok = self.src[self.cursor]
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self.pos = self.cursor
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self.cursor += 1
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self.val = None
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self.tok = self.scan_token()
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if self.tok is not None:
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return
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def check_keyword(self, rest):
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if not self.src.startswith(rest, self.cursor):
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return False
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length = len(rest)
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if self.src[self.cursor + length].isalnum() or self.src[self.cursor + length] == '|':
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return False
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self.cursor += length
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return True
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def scan_token(self):
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if self.tok == '#':
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self.cursor = self.src.find('\n', self.cursor)
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return None
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elif self.tok == '=':
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return TOK_EQUAL
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elif self.tok == '(':
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return TOK_LPAREN
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elif self.tok == ')':
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return TOK_RPAREN
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elif self.tok == '&' and self.src[self.pos+1] == '&':
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self.cursor += 1
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return TOK_AND
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elif self.tok == '|' and self.src[self.pos+1] == '|':
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self.cursor += 1
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return TOK_OR
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elif self.tok == '!':
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return TOK_NOT
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elif self.tok == 'd' and self.check_keyword("epends"):
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return TOK_DEPENDS
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elif self.tok == 'o' and self.check_keyword("n"):
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return TOK_ON
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elif self.tok == 's' and self.check_keyword("elect"):
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return TOK_SELECT
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elif self.tok == 'i' and self.check_keyword("mply"):
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return TOK_IMPLY
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elif self.tok == 'c' and self.check_keyword("onfig"):
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return TOK_CONFIG
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elif self.tok == 'd' and self.check_keyword("efault"):
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return TOK_DEFAULT
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elif self.tok == 'b' and self.check_keyword("ool"):
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return TOK_BOOL
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elif self.tok == 'i' and self.check_keyword("f"):
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return TOK_IF
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elif self.tok == 'y' and self.check_keyword(""):
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return TOK_Y
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elif self.tok == 'n' and self.check_keyword(""):
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return TOK_N
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elif (self.tok == 's' and self.check_keyword("ource")) or \
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self.tok == 'i' and self.check_keyword("nclude"):
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# source FILENAME
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# include FILENAME
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while self.src[self.cursor].isspace():
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self.cursor += 1
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start = self.cursor
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self.cursor = self.src.find('\n', self.cursor)
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self.val = self.src[start:self.cursor]
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return TOK_SOURCE
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elif self.tok.isalpha():
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# identifier
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while self.src[self.cursor].isalnum() or self.src[self.cursor] == '_':
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self.cursor += 1
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self.val = self.src[self.pos:self.cursor]
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return TOK_ID
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elif self.tok == '\n':
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if self.cursor == len(self.src):
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return TOK_EOF
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self.line += 1
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self.line_pos = self.cursor
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elif not self.tok.isspace():
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raise KconfigParserError(self, 'invalid input')
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return None
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if __name__ == '__main__':
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fname = len(sys.argv) > 1 and sys.argv[1] or 'Kconfig.test'
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KconfigParser.parse(open(fname, 'r'))
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