shell bypass 403
# Copyright (c) 2012 Google Inc. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
from __future__ import with_statement
import errno
import filecmp
import os.path
import re
import tempfile
import sys
# A minimal memoizing decorator. It'll blow up if the args aren't immutable,
# among other "problems".
class memoize(object):
def __init__(self, func):
self.func = func
self.cache = {}
def __call__(self, *args):
try:
return self.cache[args]
except KeyError:
result = self.func(*args)
self.cache[args] = result
return result
class GypError(Exception):
"""Error class representing an error, which is to be presented
to the user. The main entry point will catch and display this.
"""
pass
def ExceptionAppend(e, msg):
"""Append a message to the given exception's message."""
if not e.args:
e.args = (msg,)
elif len(e.args) == 1:
e.args = (str(e.args[0]) + ' ' + msg,)
else:
e.args = (str(e.args[0]) + ' ' + msg,) + e.args[1:]
def ParseQualifiedTarget(target):
# Splits a qualified target into a build file, target name and toolset.
# NOTE: rsplit is used to disambiguate the Windows drive letter separator.
target_split = target.rsplit(':', 1)
if len(target_split) == 2:
[build_file, target] = target_split
else:
build_file = None
target_split = target.rsplit('#', 1)
if len(target_split) == 2:
[target, toolset] = target_split
else:
toolset = None
return [build_file, target, toolset]
def ResolveTarget(build_file, target, toolset):
# This function resolves a target into a canonical form:
# - a fully defined build file, either absolute or relative to the current
# directory
# - a target name
# - a toolset
#
# build_file is the file relative to which 'target' is defined.
# target is the qualified target.
# toolset is the default toolset for that target.
[parsed_build_file, target, parsed_toolset] = ParseQualifiedTarget(target)
if parsed_build_file:
if build_file:
# If a relative path, parsed_build_file is relative to the directory
# containing build_file. If build_file is not in the current directory,
# parsed_build_file is not a usable path as-is. Resolve it by
# interpreting it as relative to build_file. If parsed_build_file is
# absolute, it is usable as a path regardless of the current directory,
# and os.path.join will return it as-is.
build_file = os.path.normpath(os.path.join(os.path.dirname(build_file),
parsed_build_file))
# Further (to handle cases like ../cwd), make it relative to cwd)
if not os.path.isabs(build_file):
build_file = RelativePath(build_file, '.')
else:
build_file = parsed_build_file
if parsed_toolset:
toolset = parsed_toolset
return [build_file, target, toolset]
def BuildFile(fully_qualified_target):
# Extracts the build file from the fully qualified target.
return ParseQualifiedTarget(fully_qualified_target)[0]
def GetEnvironFallback(var_list, default):
"""Look up a key in the environment, with fallback to secondary keys
and finally falling back to a default value."""
for var in var_list:
if var in os.environ:
return os.environ[var]
return default
def QualifiedTarget(build_file, target, toolset):
# "Qualified" means the file that a target was defined in and the target
# name, separated by a colon, suffixed by a # and the toolset name:
# /path/to/file.gyp:target_name#toolset
fully_qualified = build_file + ':' + target
if toolset:
fully_qualified = fully_qualified + '#' + toolset
return fully_qualified
@memoize
def RelativePath(path, relative_to):
# Assuming both |path| and |relative_to| are relative to the current
# directory, returns a relative path that identifies path relative to
# relative_to.
# Convert to normalized (and therefore absolute paths).
path = os.path.realpath(path)
relative_to = os.path.realpath(relative_to)
# Split the paths into components.
path_split = path.split(os.path.sep)
relative_to_split = relative_to.split(os.path.sep)
# Determine how much of the prefix the two paths share.
prefix_len = len(os.path.commonprefix([path_split, relative_to_split]))
# Put enough ".." components to back up out of relative_to to the common
# prefix, and then append the part of path_split after the common prefix.
relative_split = [os.path.pardir] * (len(relative_to_split) - prefix_len) + \
path_split[prefix_len:]
if len(relative_split) == 0:
# The paths were the same.
return ''
# Turn it back into a string and we're done.
return os.path.join(*relative_split)
@memoize
def InvertRelativePath(path, toplevel_dir=None):
"""Given a path like foo/bar that is relative to toplevel_dir, return
the inverse relative path back to the toplevel_dir.
E.g. os.path.normpath(os.path.join(path, InvertRelativePath(path)))
should always produce the empty string, unless the path contains symlinks.
"""
if not path:
return path
toplevel_dir = '.' if toplevel_dir is None else toplevel_dir
return RelativePath(toplevel_dir, os.path.join(toplevel_dir, path))
def FixIfRelativePath(path, relative_to):
# Like RelativePath but returns |path| unchanged if it is absolute.
if os.path.isabs(path):
return path
return RelativePath(path, relative_to)
def UnrelativePath(path, relative_to):
# Assuming that |relative_to| is relative to the current directory, and |path|
# is a path relative to the dirname of |relative_to|, returns a path that
# identifies |path| relative to the current directory.
rel_dir = os.path.dirname(relative_to)
return os.path.normpath(os.path.join(rel_dir, path))
# re objects used by EncodePOSIXShellArgument. See IEEE 1003.1 XCU.2.2 at
# http://www.opengroup.org/onlinepubs/009695399/utilities/xcu_chap02.html#tag_02_02
# and the documentation for various shells.
# _quote is a pattern that should match any argument that needs to be quoted
# with double-quotes by EncodePOSIXShellArgument. It matches the following
# characters appearing anywhere in an argument:
# \t, \n, space parameter separators
# # comments
# $ expansions (quoted to always expand within one argument)
# % called out by IEEE 1003.1 XCU.2.2
# & job control
# ' quoting
# (, ) subshell execution
# *, ?, [ pathname expansion
# ; command delimiter
# <, >, | redirection
# = assignment
# {, } brace expansion (bash)
# ~ tilde expansion
# It also matches the empty string, because "" (or '') is the only way to
# represent an empty string literal argument to a POSIX shell.
#
# This does not match the characters in _escape, because those need to be
# backslash-escaped regardless of whether they appear in a double-quoted
# string.
_quote = re.compile('[\t\n #$%&\'()*;<=>?[{|}~]|^$')
# _escape is a pattern that should match any character that needs to be
# escaped with a backslash, whether or not the argument matched the _quote
# pattern. _escape is used with re.sub to backslash anything in _escape's
# first match group, hence the (parentheses) in the regular expression.
#
# _escape matches the following characters appearing anywhere in an argument:
# " to prevent POSIX shells from interpreting this character for quoting
# \ to prevent POSIX shells from interpreting this character for escaping
# ` to prevent POSIX shells from interpreting this character for command
# substitution
# Missing from this list is $, because the desired behavior of
# EncodePOSIXShellArgument is to permit parameter (variable) expansion.
#
# Also missing from this list is !, which bash will interpret as the history
# expansion character when history is enabled. bash does not enable history
# by default in non-interactive shells, so this is not thought to be a problem.
# ! was omitted from this list because bash interprets "\!" as a literal string
# including the backslash character (avoiding history expansion but retaining
# the backslash), which would not be correct for argument encoding. Handling
# this case properly would also be problematic because bash allows the history
# character to be changed with the histchars shell variable. Fortunately,
# as history is not enabled in non-interactive shells and
# EncodePOSIXShellArgument is only expected to encode for non-interactive
# shells, there is no room for error here by ignoring !.
_escape = re.compile(r'(["\\`])')
def EncodePOSIXShellArgument(argument):
"""Encodes |argument| suitably for consumption by POSIX shells.
argument may be quoted and escaped as necessary to ensure that POSIX shells
treat the returned value as a literal representing the argument passed to
this function. Parameter (variable) expansions beginning with $ are allowed
to remain intact without escaping the $, to allow the argument to contain
references to variables to be expanded by the shell.
"""
if not isinstance(argument, str):
argument = str(argument)
if _quote.search(argument):
quote = '"'
else:
quote = ''
encoded = quote + re.sub(_escape, r'\\\1', argument) + quote
return encoded
def EncodePOSIXShellList(list):
"""Encodes |list| suitably for consumption by POSIX shells.
Returns EncodePOSIXShellArgument for each item in list, and joins them
together using the space character as an argument separator.
"""
encoded_arguments = []
for argument in list:
encoded_arguments.append(EncodePOSIXShellArgument(argument))
return ' '.join(encoded_arguments)
def DeepDependencyTargets(target_dicts, roots):
"""Returns the recursive list of target dependencies."""
dependencies = set()
pending = set(roots)
while pending:
# Pluck out one.
r = pending.pop()
# Skip if visited already.
if r in dependencies:
continue
# Add it.
dependencies.add(r)
# Add its children.
spec = target_dicts[r]
pending.update(set(spec.get('dependencies', [])))
pending.update(set(spec.get('dependencies_original', [])))
return list(dependencies - set(roots))
def BuildFileTargets(target_list, build_file):
"""From a target_list, returns the subset from the specified build_file.
"""
return [p for p in target_list if BuildFile(p) == build_file]
def AllTargets(target_list, target_dicts, build_file):
"""Returns all targets (direct and dependencies) for the specified build_file.
"""
bftargets = BuildFileTargets(target_list, build_file)
deptargets = DeepDependencyTargets(target_dicts, bftargets)
return bftargets + deptargets
def WriteOnDiff(filename):
"""Write to a file only if the new contents differ.
Arguments:
filename: name of the file to potentially write to.
Returns:
A file like object which will write to temporary file and only overwrite
the target if it differs (on close).
"""
class Writer:
"""Wrapper around file which only covers the target if it differs."""
def __init__(self):
# Pick temporary file.
tmp_fd, self.tmp_path = tempfile.mkstemp(
suffix='.tmp',
prefix=os.path.split(filename)[1] + '.gyp.',
dir=os.path.split(filename)[0])
try:
self.tmp_file = os.fdopen(tmp_fd, 'wb')
except Exception:
# Don't leave turds behind.
os.unlink(self.tmp_path)
raise
def __getattr__(self, attrname):
# Delegate everything else to self.tmp_file
return getattr(self.tmp_file, attrname)
def close(self):
try:
# Close tmp file.
self.tmp_file.close()
# Determine if different.
same = False
try:
same = filecmp.cmp(self.tmp_path, filename, False)
except OSError, e:
if e.errno != errno.ENOENT:
raise
if same:
# The new file is identical to the old one, just get rid of the new
# one.
os.unlink(self.tmp_path)
else:
# The new file is different from the old one, or there is no old one.
# Rename the new file to the permanent name.
#
# tempfile.mkstemp uses an overly restrictive mode, resulting in a
# file that can only be read by the owner, regardless of the umask.
# There's no reason to not respect the umask here, which means that
# an extra hoop is required to fetch it and reset the new file's mode.
#
# No way to get the umask without setting a new one? Set a safe one
# and then set it back to the old value.
umask = os.umask(077)
os.umask(umask)
os.chmod(self.tmp_path, 0666 & ~umask)
if sys.platform == 'win32' and os.path.exists(filename):
# NOTE: on windows (but not cygwin) rename will not replace an
# existing file, so it must be preceded with a remove. Sadly there
# is no way to make the switch atomic.
os.remove(filename)
os.rename(self.tmp_path, filename)
except Exception:
# Don't leave turds behind.
os.unlink(self.tmp_path)
raise
return Writer()
def GetFlavor(params):
"""Returns |params.flavor| if it's set, the system's default flavor else."""
flavors = {
'cygwin': 'win',
'win32': 'win',
'darwin': 'mac',
}
if 'flavor' in params:
return params['flavor']
if sys.platform in flavors:
return flavors[sys.platform]
if sys.platform.startswith('sunos'):
return 'solaris'
if sys.platform.startswith('freebsd'):
return 'freebsd'
if sys.platform.startswith('openbsd'):
return 'openbsd'
if sys.platform.startswith('aix'):
return 'aix'
return 'linux'
def CopyTool(flavor, out_path):
"""Finds (mac|sun|win)_tool.gyp in the gyp directory and copies it
to |out_path|."""
prefix = { 'solaris': 'sun', 'mac': 'mac', 'win': 'win' }.get(flavor, None)
if not prefix:
return
# Slurp input file.
source_path = os.path.join(
os.path.dirname(os.path.abspath(__file__)), '%s_tool.py' % prefix)
with open(source_path) as source_file:
source = source_file.readlines()
# Add header and write it out.
tool_path = os.path.join(out_path, 'gyp-%s-tool' % prefix)
with open(tool_path, 'w') as tool_file:
tool_file.write(
''.join([source[0], '# Generated by gyp. Do not edit.\n'] + source[1:]))
# Make file executable.
os.chmod(tool_path, 0755)
# From Alex Martelli,
# http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/52560
# ASPN: Python Cookbook: Remove duplicates from a sequence
# First comment, dated 2001/10/13.
# (Also in the printed Python Cookbook.)
def uniquer(seq, idfun=None):
if idfun is None:
idfun = lambda x: x
seen = {}
result = []
for item in seq:
marker = idfun(item)
if marker in seen: continue
seen[marker] = 1
result.append(item)
return result
class CycleError(Exception):
"""An exception raised when an unexpected cycle is detected."""
def __init__(self, nodes):
self.nodes = nodes
def __str__(self):
return 'CycleError: cycle involving: ' + str(self.nodes)
def TopologicallySorted(graph, get_edges):
"""Topologically sort based on a user provided edge definition.
Args:
graph: A list of node names.
get_edges: A function mapping from node name to a hashable collection
of node names which this node has outgoing edges to.
Returns:
A list containing all of the node in graph in topological order.
It is assumed that calling get_edges once for each node and caching is
cheaper than repeatedly calling get_edges.
Raises:
CycleError in the event of a cycle.
Example:
graph = {'a': '$(b) $(c)', 'b': 'hi', 'c': '$(b)'}
def GetEdges(node):
return re.findall(r'\$\(([^))]\)', graph[node])
print TopologicallySorted(graph.keys(), GetEdges)
==>
['a', 'c', b']
"""
get_edges = memoize(get_edges)
visited = set()
visiting = set()
ordered_nodes = []
def Visit(node):
if node in visiting:
raise CycleError(visiting)
if node in visited:
return
visited.add(node)
visiting.add(node)
for neighbor in get_edges(node):
Visit(neighbor)
visiting.remove(node)
ordered_nodes.insert(0, node)
for node in sorted(graph):
Visit(node)
return ordered_nodes