import os
import sys
import tempfile
import operator
import functools
import itertools
import re

import pkg_resources

if os.name == "java":
    import org.python.modules.posix.PosixModule as _os
else:
    _os = sys.modules[os.name]
try:
    _file = file
except NameError:
    _file = None
_open = open
from distutils.errors import DistutilsError
from pkg_resources import working_set

from setuptools.compat import builtins

__all__ = [
    "AbstractSandbox", "DirectorySandbox", "SandboxViolation", "run_setup",
]

def _execfile(filename, globals, locals=None):
    """
    Python 3 implementation of execfile.
    """
    with open(filename, 'rb') as stream:
        script = stream.read()
    if locals is None:
        locals = globals
    code = compile(script, filename, 'exec')
    exec(code, globals, locals)

def run_setup(setup_script, args):
    """Run a distutils setup script, sandboxed in its directory"""
    old_dir = os.getcwd()
    save_argv = sys.argv[:]
    save_path = sys.path[:]
    setup_dir = os.path.abspath(os.path.dirname(setup_script))
    temp_dir = os.path.join(setup_dir,'temp')
    if not os.path.isdir(temp_dir): os.makedirs(temp_dir)
    save_tmp = tempfile.tempdir
    save_modules = sys.modules.copy()
    pr_state = pkg_resources.__getstate__()
    try:
        tempfile.tempdir = temp_dir
        os.chdir(setup_dir)
        try:
            sys.argv[:] = [setup_script]+list(args)
            sys.path.insert(0, setup_dir)
            # reset to include setup dir, w/clean callback list
            working_set.__init__()
            working_set.callbacks.append(lambda dist:dist.activate())
            def runner():
                ns = dict(__file__=setup_script, __name__='__main__')
                _execfile(setup_script, ns)
            DirectorySandbox(setup_dir).run(runner)
        except SystemExit:
            v = sys.exc_info()[1]
            if v.args and v.args[0]:
                raise
            # Normal exit, just return
    finally:
        pkg_resources.__setstate__(pr_state)
        sys.modules.update(save_modules)
        # remove any modules imported within the sandbox
        del_modules = [
            mod_name for mod_name in sys.modules
            if mod_name not in save_modules
            # exclude any encodings modules. See #285
            and not mod_name.startswith('encodings.')
        ]
        list(map(sys.modules.__delitem__, del_modules))
        os.chdir(old_dir)
        sys.path[:] = save_path
        sys.argv[:] = save_argv
        tempfile.tempdir = save_tmp


class AbstractSandbox:
    """Wrap 'os' module and 'open()' builtin for virtualizing setup scripts"""

    _active = False

    def __init__(self):
        self._attrs = [
            name for name in dir(_os)
                if not name.startswith('_') and hasattr(self,name)
        ]

    def _copy(self, source):
        for name in self._attrs:
            setattr(os, name, getattr(source,name))

    def run(self, func):
        """Run 'func' under os sandboxing"""
        try:
            self._copy(self)
            if _file:
                builtins.file = self._file
            builtins.open = self._open
            self._active = True
            return func()
        finally:
            self._active = False
            if _file:
                builtins.file = _file
            builtins.open = _open
            self._copy(_os)

    def _mk_dual_path_wrapper(name):
        original = getattr(_os,name)
        def wrap(self,src,dst,*args,**kw):
            if self._active:
                src,dst = self._remap_pair(name,src,dst,*args,**kw)
            return original(src,dst,*args,**kw)
        return wrap

    for name in ["rename", "link", "symlink"]:
        if hasattr(_os,name): locals()[name] = _mk_dual_path_wrapper(name)

    def _mk_single_path_wrapper(name, original=None):
        original = original or getattr(_os,name)
        def wrap(self,path,*args,**kw):
            if self._active:
                path = self._remap_input(name,path,*args,**kw)
            return original(path,*args,**kw)
        return wrap

    if _file:
        _file = _mk_single_path_wrapper('file', _file)
    _open = _mk_single_path_wrapper('open', _open)
    for name in [
        "stat", "listdir", "chdir", "open", "chmod", "chown", "mkdir",
        "remove", "unlink", "rmdir", "utime", "lchown", "chroot", "lstat",
        "startfile", "mkfifo", "mknod", "pathconf", "access"
    ]:
        if hasattr(_os,name): locals()[name] = _mk_single_path_wrapper(name)

    def _mk_single_with_return(name):
        original = getattr(_os,name)
        def wrap(self,path,*args,**kw):
            if self._active:
                path = self._remap_input(name,path,*args,**kw)
                return self._remap_output(name, original(path,*args,**kw))
            return original(path,*args,**kw)
        return wrap

    for name in ['readlink', 'tempnam']:
        if hasattr(_os,name): locals()[name] = _mk_single_with_return(name)

    def _mk_query(name):
        original = getattr(_os,name)
        def wrap(self,*args,**kw):
            retval = original(*args,**kw)
            if self._active:
                return self._remap_output(name, retval)
            return retval
        return wrap

    for name in ['getcwd', 'tmpnam']:
        if hasattr(_os,name): locals()[name] = _mk_query(name)

    def _validate_path(self,path):
        """Called to remap or validate any path, whether input or output"""
        return path

    def _remap_input(self,operation,path,*args,**kw):
        """Called for path inputs"""
        return self._validate_path(path)

    def _remap_output(self,operation,path):
        """Called for path outputs"""
        return self._validate_path(path)

    def _remap_pair(self,operation,src,dst,*args,**kw):
        """Called for path pairs like rename, link, and symlink operations"""
        return (
            self._remap_input(operation+'-from',src,*args,**kw),
            self._remap_input(operation+'-to',dst,*args,**kw)
        )


if hasattr(os, 'devnull'):
    _EXCEPTIONS = [os.devnull,]
else:
    _EXCEPTIONS = []

try:
    from win32com.client.gencache import GetGeneratePath
    _EXCEPTIONS.append(GetGeneratePath())
    del GetGeneratePath
except ImportError:
    # it appears pywin32 is not installed, so no need to exclude.
    pass

class DirectorySandbox(AbstractSandbox):
    """Restrict operations to a single subdirectory - pseudo-chroot"""

    write_ops = dict.fromkeys([
        "open", "chmod", "chown", "mkdir", "remove", "unlink", "rmdir",
        "utime", "lchown", "chroot", "mkfifo", "mknod", "tempnam",
    ])

    _exception_patterns = [
        # Allow lib2to3 to attempt to save a pickled grammar object (#121)
        '.*lib2to3.*\.pickle$',
    ]
    "exempt writing to paths that match the pattern"

    def __init__(self, sandbox, exceptions=_EXCEPTIONS):
        self._sandbox = os.path.normcase(os.path.realpath(sandbox))
        self._prefix = os.path.join(self._sandbox,'')
        self._exceptions = [
            os.path.normcase(os.path.realpath(path))
            for path in exceptions
        ]
        AbstractSandbox.__init__(self)

    def _violation(self, operation, *args, **kw):
        raise SandboxViolation(operation, args, kw)

    if _file:
        def _file(self, path, mode='r', *args, **kw):
            if mode not in ('r', 'rt', 'rb', 'rU', 'U') and not self._ok(path):
                self._violation("file", path, mode, *args, **kw)
            return _file(path,mode,*args,**kw)

    def _open(self, path, mode='r', *args, **kw):
        if mode not in ('r', 'rt', 'rb', 'rU', 'U') and not self._ok(path):
            self._violation("open", path, mode, *args, **kw)
        return _open(path,mode,*args,**kw)

    def tmpnam(self):
        self._violation("tmpnam")

    def _ok(self, path):
        active = self._active
        try:
            self._active = False
            realpath = os.path.normcase(os.path.realpath(path))
            return (
                self._exempted(realpath)
                or realpath == self._sandbox
                or realpath.startswith(self._prefix)
            )
        finally:
            self._active = active

    def _exempted(self, filepath):
        start_matches = (
            filepath.startswith(exception)
            for exception in self._exceptions
        )
        pattern_matches = (
            re.match(pattern, filepath)
            for pattern in self._exception_patterns
        )
        candidates = itertools.chain(start_matches, pattern_matches)
        return any(candidates)

    def _remap_input(self, operation, path, *args, **kw):
        """Called for path inputs"""
        if operation in self.write_ops and not self._ok(path):
            self._violation(operation, os.path.realpath(path), *args, **kw)
        return path

    def _remap_pair(self, operation, src, dst, *args, **kw):
        """Called for path pairs like rename, link, and symlink operations"""
        if not self._ok(src) or not self._ok(dst):
            self._violation(operation, src, dst, *args, **kw)
        return (src,dst)

    def open(self, file, flags, mode=0o777, *args, **kw):
        """Called for low-level os.open()"""
        if flags & WRITE_FLAGS and not self._ok(file):
            self._violation("os.open", file, flags, mode, *args, **kw)
        return _os.open(file,flags,mode, *args, **kw)

WRITE_FLAGS = functools.reduce(
    operator.or_, [getattr(_os, a, 0) for a in
        "O_WRONLY O_RDWR O_APPEND O_CREAT O_TRUNC O_TEMPORARY".split()]
)

class SandboxViolation(DistutilsError):
    """A setup script attempted to modify the filesystem outside the sandbox"""

    def __str__(self):
        return """SandboxViolation: %s%r %s

The package setup script has attempted to modify files on your system
that are not within the EasyInstall build area, and has been aborted.

This package cannot be safely installed by EasyInstall, and may not
support alternate installation locations even if you run its setup
script by hand.  Please inform the package's author and the EasyInstall
maintainers to find out if a fix or workaround is available.""" % self.args



























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