From: Paolo Bonzini <pbonz...@redhat.com>
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 <pbonz...@redhat.com>
---
scripts/minikconf.py | 423 +++++++++++++++++++++++++++++++++++++++++++
1 file changed, 423 insertions(+)
create mode 100644 scripts/minikconf.py
diff --git a/scripts/minikconf.py b/scripts/minikconf.py
new file mode 100644
index 0000000000..fb39e35d6a
--- /dev/null
+++ b/scripts/minikconf.py
@@ -0,0 +1,423 @@
+#
+# Mini-Kconfig parser
+#
+# Copyright (c) 2015 Red Hat Inc.
+#
+# Authors:
+# Paolo Bonzini <pbonz...@redhat.com>
+#
+# This work is licensed under the terms of the GNU GPL, version 2
+# or, at your option, any later version. See the COPYING file in
+# the top-level directory.
+
+import os
+import sys
+
+__all__ = [ 'KconfigParserError', 'KconfigData', 'KconfigParser' ]
+
+# -------------------------------------------
+# KconfigData implements the Kconfig semantics. For now it can only
+# detect undefined symbols, i.e. symbols that were referenced in
+# assignments or dependencies but were not declared with "config FOO".
+#
+# Semantic actions are represented by methods called do_*. The do_var
+# method return the semantic value of a variable (which right now is
+# just its name).
+# -------------------------------------------
+
+class KconfigData:
+ def __init__(self):
+ self.previously_included = []
+ self.incl_info = None
+ self.defined_vars = set()
+ self.referenced_vars = set()
+
+ # semantic analysis -------------
+
+ def check_undefined(self):
+ undef = False
+ for i in self.referenced_vars:
+ if not (i in self.defined_vars):
+ print "undefined symbol %s" % (i)
+ undef = True
+ return undef
+
+ # semantic actions -------------
+
+ def do_declaration(self, var):
+ if (var in self.defined_vars):
+ raise Exception('variable "' + var + '" defined twice')
+
+ self.defined_vars.add(var)
+
+ # var is a string with the variable's name.
+ #
+ # For now this just returns the variable's name itself.
+ def do_var(self, var):
+ self.referenced_vars.add(var)
+ return var
+
+ def do_assignment(self, var, val):
+ pass
+
+ def do_default(self, var, val, cond=None):
+ pass
+
+ def do_depends_on(self, var, expr):
+ pass
+
+ def do_select(self, var, symbol, cond=None):
+ pass
+
+# -------------------------------------------
+# KconfigParser implements a recursive descent parser for (simplified)
+# Kconfig syntax.
+# -------------------------------------------
+
+# tokens table
+TOKENS = {}
+TOK_NONE = -1
+TOK_LPAREN = 0; TOKENS[TOK_LPAREN] = '"("';
+TOK_RPAREN = 1; TOKENS[TOK_RPAREN] = '")"';
+TOK_EQUAL = 2; TOKENS[TOK_EQUAL] = '"="';
+TOK_AND = 3; TOKENS[TOK_AND] = '"&&"';
+TOK_OR = 4; TOKENS[TOK_OR] = '"||"';
+TOK_NOT = 5; TOKENS[TOK_NOT] = '"!"';
+TOK_DEPENDS = 6; TOKENS[TOK_DEPENDS] = '"depends"';
+TOK_ON = 7; TOKENS[TOK_ON] = '"on"';
+TOK_SELECT = 8; TOKENS[TOK_SELECT] = '"select"';
+TOK_CONFIG = 9; TOKENS[TOK_CONFIG] = '"config"';
+TOK_DEFAULT = 10; TOKENS[TOK_DEFAULT] = '"default"';
+TOK_Y = 11; TOKENS[TOK_Y] = '"y"';
+TOK_N = 12; TOKENS[TOK_N] = '"n"';
+TOK_SOURCE = 13; TOKENS[TOK_SOURCE] = '"source"';
+TOK_BOOL = 14; TOKENS[TOK_BOOL] = '"bool"';
+TOK_IF = 15; TOKENS[TOK_IF] = '"if"';
+TOK_ID = 16; TOKENS[TOK_ID] = 'identifier';
+TOK_EOF = 17; TOKENS[TOK_EOF] = 'end of file';
+
+class KconfigParserError(Exception):
+ def __init__(self, parser, msg, tok=None):
+ self.loc = parser.location()
+ tok = tok or parser.tok
+ if tok != TOK_NONE:
+ msg = '%s before %s' %(msg, TOKENS[tok])
+ self.msg = msg
+
+ def __str__(self):
+ return "%s: %s" % (self.loc, self.msg)
+
+class KconfigParser:
+ @classmethod
+ def parse(self, fp):
+ data = KconfigData()
+ parser = KconfigParser(data)
+ parser.parse_file(fp)
+ if data.check_undefined():
+ raise KconfigParserError(parser, "there were undefined symbols")
+
+ return data
+
+ def __init__(self, data):
+ self.data = data
+
+ def parse_file(self, fp):
+ self.abs_fname = os.path.abspath(fp.name)
+ self.fname = fp.name
+ self.data.previously_included.append(self.abs_fname)
+ self.src = fp.read()
+ if self.src == '' or self.src[-1] != '\n':
+ self.src += '\n'
+ self.cursor = 0
+ self.line = 1
+ self.line_pos = 0
+ self.get_token()
+ self.parse_config()
+
+ # file management -----
+
+ def error_path(self):
+ inf = self.data.incl_info
+ res = ""
+ while inf:
+ res = ("In file included from %s:%d:\n" % (inf['file'],
+ inf['line'])) + res
+ inf = inf['parent']
+ return res
+
+ def location(self):
+ col = 1
+ for ch in self.src[self.line_pos:self.pos]:
+ if ch == '\t':
+ col += 8 - ((col - 1) % 8)
+ else:
+ col += 1
+ return '%s%s:%d:%d' %(self.error_path(), self.fname, self.line, col)
+
+ def do_include(self, include):
+ incl_abs_fname = os.path.join(os.path.dirname(self.abs_fname),
+ include)
+ # catch inclusion cycle
+ inf = self.data.incl_info
+ while inf:
+ if incl_abs_fname == os.path.abspath(inf['file']):
+ raise KconfigParserError(self, "Inclusion loop for %s"
+ % include)
+ inf = inf['parent']
+
+ # skip multiple include of the same file
+ if incl_abs_fname in self.data.previously_included:
+ return
+ try:
+ fp = open(incl_abs_fname, 'r')
+ except IOError, e:
+ raise KconfigParserError(self,
+ '%s: %s' % (e.strerror, include))
+
+ inf = self.data.incl_info
+ self.data.incl_info = { 'file': self.fname, 'line': self.line,
+ 'parent': inf }
+ KconfigParser(self.data).parse_file(fp)
+ self.data.incl_info = inf
+
+ # recursive descent parser -----
+
+ # y_or_n: Y | N
+ def parse_y_or_n(self):
+ if self.tok == TOK_Y:
+ self.get_token()
+ return True
+ if self.tok == TOK_N:
+ self.get_token()
+ return False
+ raise KconfigParserError(self, 'Expected "y" or "n"')
+
+ # var: ID
+ def parse_var(self):
+ if self.tok == TOK_ID:
+ val = self.val
+ self.get_token()
+ return self.data.do_var(val)
+ else:
+ raise KconfigParserError(self, 'Expected identifier')
+
+ # assignment_var: ID (starting with "CONFIG_")
+ def parse_assignment_var(self):
+ if self.tok == TOK_ID:
+ val = self.val
+ if not val.startswith("CONFIG_"):
+ raise KconfigParserError(self,
+ 'Expected identifier starting with "CONFIG_"',
TOK_NONE)
+ self.get_token()
+ return self.data.do_var(val[7:])
+ else:
+ raise KconfigParserError(self, 'Expected identifier')
+
+ # assignment: var EQUAL y_or_n
+ def parse_assignment(self):
+ var = self.parse_assignment_var()
+ if self.tok != TOK_EQUAL:
+ raise KconfigParserError(self, 'Expected "="')
+ self.get_token()
+ self.data.do_assignment(var, self.parse_y_or_n())
+
+ # primary: NOT primary
+ # | LPAREN expr RPAREN
+ # | var
+ def parse_primary(self):
+ if self.tok == TOK_NOT:
+ self.get_token()
+ self.parse_primary()
+ elif self.tok == TOK_LPAREN:
+ self.get_token()
+ self.parse_expr()
+ if self.tok != TOK_RPAREN:
+ raise KconfigParserError(self, 'Expected ")"')
+ self.get_token()
+ elif self.tok == TOK_ID:
+ self.parse_var()
+ else:
+ raise KconfigParserError(self, 'Expected "!" or "(" or identifier')
+
+ # disj: primary (OR primary)*
+ def parse_disj(self):
+ self.parse_primary()
+ while self.tok == TOK_OR:
+ self.get_token()
+ self.parse_primary()
+
+ # expr: disj (AND disj)*
+ def parse_expr(self):
+ self.parse_disj()
+ while self.tok == TOK_AND:
+ self.get_token()
+ self.parse_disj()
+
+ # condition: IF expr
+ # | empty
+ def parse_condition(self):
+ if self.tok == TOK_IF:
+ self.get_token()
+ return self.parse_expr()
+ else:
+ return None
+
+ # property: DEFAULT y_or_n condition
+ # | DEPENDS ON expr
+ # | SELECT var condition
+ # | BOOL
+ def parse_property(self, var):
+ if self.tok == TOK_DEFAULT:
+ self.get_token()
+ val = self.parse_y_or_n()
+ cond = self.parse_condition()
+ self.data.do_default(var, val, cond)
+ elif self.tok == TOK_DEPENDS:
+ self.get_token()
+ if self.tok != TOK_ON:
+ raise KconfigParserError(self, 'Expected "on"')
+ self.get_token()
+ self.data.do_depends_on(var, self.parse_expr())
+ elif self.tok == TOK_SELECT:
+ self.get_token()
+ symbol = self.parse_var()
+ cond = self.parse_condition()
+ self.data.do_select(var, symbol, cond)
+ elif self.tok == TOK_BOOL:
+ self.get_token()
+ else:
+ raise KconfigParserError(self, 'Error in recursive descent?')
+
+ # properties: properties property
+ # | /* empty */
+ def parse_properties(self, var):
+ had_default = False
+ while self.tok == TOK_DEFAULT or self.tok == TOK_DEPENDS or \
+ self.tok == TOK_SELECT or self.tok == TOK_BOOL:
+ self.parse_property(var)
+ self.data.do_default(var, False)
+
+ # for nicer error message
+ if self.tok != TOK_SOURCE and self.tok != TOK_CONFIG and \
+ self.tok != TOK_ID and self.tok != TOK_EOF:
+ raise KconfigParserError(self, 'expected "source", "config",
identifier, '
+ + '"default", "depends on" or "select"')
+
+ # declaration: config var properties
+ def parse_declaration(self):
+ if self.tok == TOK_CONFIG:
+ self.get_token()
+ var = self.parse_var()
+ self.data.do_declaration(var)
+ self.parse_properties(var)
+ else:
+ raise KconfigParserError(self, 'Error in recursive descent?')
+
+ # clause: SOURCE
+ # | declaration
+ # | assignment
+ def parse_clause(self):
+ if self.tok == TOK_SOURCE:
+ val = self.val
+ self.get_token()
+ self.do_include(val)
+ elif self.tok == TOK_CONFIG:
+ self.parse_declaration()
+ elif self.tok == TOK_ID:
+ self.parse_assignment()
+ else:
+ raise KconfigParserError(self, 'expected "source", "config" or
identifier')
+
+ # config: clause+ EOF
+ def parse_config(self):
+ while self.tok != TOK_EOF:
+ self.parse_clause()
+ return self.data
+
+ # scanner -----
+
+ def get_token(self):
+ while True:
+ self.tok = self.src[self.cursor]
+ self.pos = self.cursor
+ self.cursor += 1
+
+ self.val = None
+ self.tok = self.scan_token()
+ if self.tok is not None:
+ return
+
+ def check_keyword(self, rest):
+ if not self.src.startswith(rest, self.cursor):
+ return False
+ length = len(rest)
+ if self.src[self.cursor + length].isalnum() or self.src[self.cursor +
length] == '|':
+ return False
+ self.cursor += length
+ return True
+
+ def scan_token(self):
+ if self.tok == '#':
+ self.cursor = self.src.find('\n', self.cursor)
+ return None
+ elif self.tok == '=':
+ return TOK_EQUAL
+ elif self.tok == '(':
+ return TOK_LPAREN
+ elif self.tok == ')':
+ return TOK_RPAREN
+ elif self.tok == '&' and self.src[self.pos+1] == '&':
+ self.cursor += 1
+ return TOK_AND
+ elif self.tok == '|' and self.src[self.pos+1] == '|':
+ self.cursor += 1
+ return TOK_OR
+ elif self.tok == '!':
+ return TOK_NOT
+ elif self.tok == 'd' and self.check_keyword("epends"):
+ return TOK_DEPENDS
+ elif self.tok == 'o' and self.check_keyword("n"):
+ return TOK_ON
+ elif self.tok == 's' and self.check_keyword("elect"):
+ return TOK_SELECT
+ elif self.tok == 'c' and self.check_keyword("onfig"):
+ return TOK_CONFIG
+ elif self.tok == 'd' and self.check_keyword("efault"):
+ return TOK_DEFAULT
+ elif self.tok == 'b' and self.check_keyword("ool"):
+ return TOK_BOOL
+ elif self.tok == 'i' and self.check_keyword("f"):
+ return TOK_IF
+ elif self.tok == 'y' and self.check_keyword(""):
+ return TOK_Y
+ elif self.tok == 'n' and self.check_keyword(""):
+ return TOK_N
+ elif (self.tok == 's' and self.check_keyword("ource")) or \
+ self.tok == 'i' and self.check_keyword("nclude"):
+ # source FILENAME
+ # include FILENAME
+ while self.src[self.cursor].isspace():
+ self.cursor += 1
+ start = self.cursor
+ self.cursor = self.src.find('\n', self.cursor)
+ self.val = self.src[start:self.cursor]
+ return TOK_SOURCE
+ elif self.tok.isalpha():
+ # identifier
+ while self.src[self.cursor].isalnum() or self.src[self.cursor] ==
'_':
+ self.cursor += 1
+ self.val = self.src[self.pos:self.cursor]
+ return TOK_ID
+ elif self.tok == '\n':
+ if self.cursor == len(self.src):
+ return TOK_EOF
+ self.line += 1
+ self.line_pos = self.cursor
+ elif not self.tok.isspace():
+ raise KconfigParserError(self, 'Stray "%s"' % self.tok)
+
+ return None
+
+if __name__ == '__main__':
+ fname = len(sys.argv) > 1 and sys.argv[1] or 'Kconfig.test'
+ KconfigParser.parse(open(fname, 'r'))
--
2.17.1
