import ast import codegen import logging import os.path import bb.utils, bb.data from itertools import chain from bb.pysh import pyshyacc, pyshlex logger = logging.getLogger('BitBake.CodeParser') PARSERCACHE_VERSION = 2 try: import cPickle as pickle except ImportError: import pickle logger.info('Importing cPickle failed. Falling back to a very slow implementation.') def check_indent(codestr): """If the code is indented, add a top level piece of code to 'remove' the indentation""" i = 0 while codestr[i] in ["\n", " ", " "]: i = i + 1 if i == 0: return codestr if codestr[i-1] is " " or codestr[i-1] is " ": return "if 1:\n" + codestr return codestr pythonparsecache = {} shellparsecache = {} def parser_cachefile(d): cachedir = (bb.data.getVar("PERSISTENT_DIR", d, True) or bb.data.getVar("CACHE", d, True)) if cachedir in [None, '']: return None bb.utils.mkdirhier(cachedir) cachefile = os.path.join(cachedir, "bb_codeparser.dat") logger.debug(1, "Using cache in '%s' for codeparser cache", cachefile) return cachefile def parser_cache_init(d): global pythonparsecache global shellparsecache cachefile = parser_cachefile(d) if not cachefile: return try: p = pickle.Unpickler(file(cachefile, "rb")) data, version = p.load() except: return if version != PARSERCACHE_VERSION: return pythonparsecache = data[0] shellparsecache = data[1] def parser_cache_save(d): cachefile = parser_cachefile(d) if not cachefile: return p = pickle.Pickler(file(cachefile, "wb"), -1) p.dump([[pythonparsecache, shellparsecache], PARSERCACHE_VERSION]) class PythonParser(): class ValueVisitor(): """Visitor to traverse a python abstract syntax tree and obtain the variables referenced via bitbake metadata APIs, and the external functions called. """ getvars = ("d.getVar", "bb.data.getVar", "data.getVar") expands = ("d.expand", "bb.data.expand", "data.expand") execs = ("bb.build.exec_func", "bb.build.exec_task") @classmethod def _compare_name(cls, strparts, node): """Given a sequence of strings representing a python name, where the last component is the actual Name and the prior elements are Attribute nodes, determine if the supplied node matches. """ if not strparts: return True current, rest = strparts[0], strparts[1:] if isinstance(node, ast.Attribute): if current == node.attr: return cls._compare_name(rest, node.value) elif isinstance(node, ast.Name): if current == node.id: return True return False @classmethod def compare_name(cls, value, node): """Convenience function for the _compare_node method, which can accept a string (which is split by '.' for you), or an iterable of strings, in which case it checks to see if any of them match, similar to isinstance. """ if isinstance(value, basestring): return cls._compare_name(tuple(reversed(value.split("."))), node) else: return any(cls.compare_name(item, node) for item in value) def __init__(self, value): self.var_references = set() self.var_execs = set() self.direct_func_calls = set() self.var_expands = set() self.value = value @classmethod def warn(cls, func, arg): """Warn about calls of bitbake APIs which pass a non-literal argument for the variable name, as we're not able to track such a reference. """ try: funcstr = codegen.to_source(func) argstr = codegen.to_source(arg) except TypeError: logger.debug(2, 'Failed to convert function and argument to source form') else: logger.debug(1, "Warning: in call to '%s', argumen t'%s' is" "not a literal", funcstr, argstr) def visit_Call(self, node): if self.compare_name(self.getvars, node.func): if isinstance(node.args[0], ast.Str): self.var_references.add(node.args[0].s) else: self.warn(node.func, node.args[0]) elif self.compare_name(self.expands, node.func): if isinstance(node.args[0], ast.Str): self.warn(node.func, node.args[0]) self.var_expands.update(node.args[0].s) elif isinstance(node.args[0], ast.Call) and \ self.compare_name(self.getvars, node.args[0].func): pass else: self.warn(node.func, node.args[0]) elif self.compare_name(self.execs, node.func): if isinstance(node.args[0], ast.Str): self.var_execs.add(node.args[0].s) else: self.warn(node.func, node.args[0]) elif isinstance(node.func, ast.Name): self.direct_func_calls.add(node.func.id) elif isinstance(node.func, ast.Attribute): # We must have a qualified name. Therefore we need # to walk the chain of 'Attribute' nodes to determine # the qualification. attr_node = node.func.value identifier = node.func.attr while isinstance(attr_node, ast.Attribute): identifier = attr_node.attr + "." + identifier attr_node = attr_node.value if isinstance(attr_node, ast.Name): identifier = attr_node.id + "." + identifier self.direct_func_calls.add(identifier) def __init__(self): #self.funcdefs = set() self.execs = set() #self.external_cmds = set() self.references = set() def parse_python(self, node): h = hash(str(node)) if h in pythonparsecache: self.references = pythonparsecache[h]["refs"] self.execs = pythonparsecache[h]["execs"] return code = compile(check_indent(str(node)), "", "exec", ast.PyCF_ONLY_AST) visitor = self.ValueVisitor(code) for n in ast.walk(code): if n.__class__.__name__ == "Call": visitor.visit_Call(n) self.references.update(visitor.var_references) self.references.update(visitor.var_execs) self.execs = visitor.direct_func_calls pythonparsecache[h] = {} pythonparsecache[h]["refs"] = self.references pythonparsecache[h]["execs"] = self.execs class ShellParser(): def __init__(self): self.funcdefs = set() self.allexecs = set() self.execs = set() def parse_shell(self, value): """Parse the supplied shell code in a string, returning the external commands it executes. """ h = hash(str(value)) if h in shellparsecache: self.execs = shellparsecache[h]["execs"] return self.execs try: tokens, _ = pyshyacc.parse(value, eof=True, debug=False) except pyshlex.NeedMore: raise ShellSyntaxError("Unexpected EOF") for token in tokens: self.process_tokens(token) self.execs = set(cmd for cmd in self.allexecs if cmd not in self.funcdefs) shellparsecache[h] = {} shellparsecache[h]["execs"] = self.execs return self.execs def process_tokens(self, tokens): """Process a supplied portion of the syntax tree as returned by pyshyacc.parse. """ def function_definition(value): self.funcdefs.add(value.name) return [value.body], None def case_clause(value): # Element 0 of each item in the case is the list of patterns, and # Element 1 of each item in the case is the list of commands to be # executed when that pattern matches. words = chain(*[item[0] for item in value.items]) cmds = chain(*[item[1] for item in value.items]) return cmds, words def if_clause(value): main = chain(value.cond, value.if_cmds) rest = value.else_cmds if isinstance(rest, tuple) and rest[0] == "elif": return chain(main, if_clause(rest[1])) else: return chain(main, rest) def simple_command(value): return None, chain(value.words, (assign[1] for assign in value.assigns)) token_handlers = { "and_or": lambda x: ((x.left, x.right), None), "async": lambda x: ([x], None), "brace_group": lambda x: (x.cmds, None), "for_clause": lambda x: (x.cmds, x.items), "function_definition": function_definition, "if_clause": lambda x: (if_clause(x), None), "pipeline": lambda x: (x.commands, None), "redirect_list": lambda x: ([x.cmd], None), "subshell": lambda x: (x.cmds, None), "while_clause": lambda x: (chain(x.condition, x.cmds), None), "until_clause": lambda x: (chain(x.condition, x.cmds), None), "simple_command": simple_command, "case_clause": case_clause, } for token in tokens: name, value = token try: more_tokens, words = token_handlers[name](value) except KeyError: raise NotImplementedError("Unsupported token type " + name) if more_tokens: self.process_tokens(more_tokens) if words: self.process_words(words) def process_words(self, words): """Process a set of 'words' in pyshyacc parlance, which includes extraction of executed commands from $() blocks, as well as grabbing the command name argument. """ words = list(words) for word in list(words): wtree = pyshlex.make_wordtree(word[1]) for part in wtree: if not isinstance(part, list): continue if part[0] in ('`', '$('): command = pyshlex.wordtree_as_string(part[1:-1]) self.parse_shell(command) if word[0] in ("cmd_name", "cmd_word"): if word in words: words.remove(word) usetoken = False for word in words: if word[0] in ("cmd_name", "cmd_word") or \ (usetoken and word[0] == "TOKEN"): if "=" in word[1]: usetoken = True continue cmd = word[1] if cmd.startswith("$"): logger.debug(1, "Warning: execution of non-literal" "command '%s'", cmd) elif cmd == "eval": command = " ".join(word for _, word in words[1:]) self.parse_shell(command) else: self.allexecs.add(cmd) break