/rpython/rlib/rposix.py

import os
import sys
import errno
from rpython.annotator.model import s_Str0
from rpython.rtyper.lltypesystem.rffi import CConstant, CExternVariable, INT
from rpython.rtyper.lltypesystem import lltype, ll2ctypes, rffi
from rpython.rtyper.tool import rffi_platform
from rpython.rlib import debug, jit, rstring, rthread, types
from rpython.rlib._os_support import (
    _CYGWIN, _MACRO_ON_POSIX, UNDERSCORE_ON_WIN32, _WIN32,
    _prefer_unicode, _preferred_traits)
from rpython.rlib.objectmodel import (
    specialize, enforceargs, register_replacement_for, NOT_CONSTANT)
from rpython.rlib.rarithmetic import intmask, widen
from rpython.rlib.signature import signature
from rpython.tool.sourcetools import func_renamer
from rpython.translator.platform import platform
from rpython.translator.tool.cbuild import ExternalCompilationInfo


if _WIN32:
    from rpython.rlib import rwin32
    from rpython.rlib.rwin32file import make_win32_traits


class CConstantErrno(CConstant):
    # these accessors are used when calling get_errno() or set_errno()
    # on top of CPython
    def __getitem__(self, index):
        assert index == 0
        try:
            return ll2ctypes.TLS.errno
        except AttributeError:
            raise ValueError("no C function call occurred so far, "
                             "errno is undefined")
    def __setitem__(self, index, value):
        assert index == 0
        ll2ctypes.TLS.errno = value

if os.name == 'nt':
    if platform.name == 'msvc':
        includes=['errno.h','stdio.h']
    else:
        includes=['errno.h','stdio.h', 'stdint.h']
    separate_module_sources =['''
        /* Lifted completely from CPython 3.3 Modules/posix_module.c */
        #include <malloc.h> /* for _msize */
        typedef struct {
            intptr_t osfhnd;
            char osfile;
        } my_ioinfo;
        extern __declspec(dllimport) char * __pioinfo[];
        #define IOINFO_L2E 5
        #define IOINFO_ARRAY_ELTS   (1 << IOINFO_L2E)
        #define IOINFO_ARRAYS 64
        #define _NHANDLE_           (IOINFO_ARRAYS * IOINFO_ARRAY_ELTS)
        #define FOPEN 0x01
        #define _NO_CONSOLE_FILENO (intptr_t)-2

        /* This function emulates what the windows CRT
            does to validate file handles */
        RPY_EXTERN int
        _PyVerify_fd(int fd)
        {
            const int i1 = fd >> IOINFO_L2E;
            const int i2 = fd & ((1 << IOINFO_L2E) - 1);

            static size_t sizeof_ioinfo = 0;

            /* Determine the actual size of the ioinfo structure,
             * as used by the CRT loaded in memory
             */
            if (sizeof_ioinfo == 0 && __pioinfo[0] != NULL) {
                sizeof_ioinfo = _msize(__pioinfo[0]) / IOINFO_ARRAY_ELTS;
            }
            if (sizeof_ioinfo == 0) {
                /* This should not happen... */
                goto fail;
            }

            /* See that it isn't a special CLEAR fileno */
                if (fd != _NO_CONSOLE_FILENO) {
                /* Microsoft CRT would check that 0<=fd<_nhandle but we can't do that.  Instead
                 * we check pointer validity and other info
                 */
                if (0 <= i1 && i1 < IOINFO_ARRAYS && __pioinfo[i1] != NULL) {
                    /* finally, check that the file is open */
                    my_ioinfo* info = (my_ioinfo*)(__pioinfo[i1] + i2 * sizeof_ioinfo);
                    if (info->osfile & FOPEN) {
                        return 1;
                    }
                }
            }
          fail:
            errno = EBADF;
            return 0;
        }
    ''',]
    post_include_bits=['RPY_EXTERN int _PyVerify_fd(int);']
else:
    separate_module_sources = []
    post_include_bits = []
    includes=['errno.h','stdio.h']
errno_eci = ExternalCompilationInfo(
    includes=includes,
    separate_module_sources=separate_module_sources,
    post_include_bits=post_include_bits,
)

# Direct getters/setters, don't use directly!
_get_errno, _set_errno = CExternVariable(INT, 'errno', errno_eci,
                                         CConstantErrno, sandboxsafe=True,
                                         _nowrapper=True, c_type='int')

def get_saved_errno():
    """Return the value of the "saved errno".
    This value is saved after a call to a C function, if it was declared
    with the flag llexternal(..., save_err=rffi.RFFI_SAVE_ERRNO).
    Functions without that flag don't change the saved errno.
    """
    return intmask(rthread.tlfield_rpy_errno.getraw())

def set_saved_errno(errno):
    """Set the value of the saved errno.  This value will be used to
    initialize the real errno just before calling the following C function,
    provided it was declared llexternal(..., save_err=RFFI_READSAVED_ERRNO).
    Note also that it is more common to want the real errno to be initially
    zero; for that case, use llexternal(..., save_err=RFFI_ZERO_ERRNO_BEFORE)
    and then you don't need set_saved_errno(0).
    """
    rthread.tlfield_rpy_errno.setraw(rffi.cast(INT, errno))

def get_saved_alterrno():
    """Return the value of the "saved alterrno".
    This value is saved after a call to a C function, if it was declared
    with the flag llexternal(..., save_err=rffi.RFFI_SAVE_ERRNO | rffl.RFFI_ALT_ERRNO).
    Functions without that flag don't change the saved errno.
    """
    return intmask(rthread.tlfield_alt_errno.getraw())

def set_saved_alterrno(errno):
    """Set the value of the saved alterrno.  This value will be used to
    initialize the real errno just before calling the following C function,
    provided it was declared llexternal(..., save_err=RFFI_READSAVED_ERRNO | rffl.RFFI_ALT_ERRNO).
    Note also that it is more common to want the real errno to be initially
    zero; for that case, use llexternal(..., save_err=RFFI_ZERO_ERRNO_BEFORE)
    and then you don't need set_saved_errno(0).
    """
    rthread.tlfield_alt_errno.setraw(rffi.cast(INT, errno))


# These are not posix specific, but where should they move to?
@specialize.call_location()
def _errno_before(save_err):
    if save_err & rffi.RFFI_READSAVED_ERRNO:
        if save_err & rffi.RFFI_ALT_ERRNO:
            _set_errno(rthread.tlfield_alt_errno.getraw())
        else:
            _set_errno(rthread.tlfield_rpy_errno.getraw())
    elif save_err & rffi.RFFI_ZERO_ERRNO_BEFORE:
        _set_errno(rffi.cast(rffi.INT, 0))
    if _WIN32 and (save_err & rffi.RFFI_READSAVED_LASTERROR):
        if save_err & rffi.RFFI_ALT_ERRNO:
            err = rthread.tlfield_alt_lasterror.getraw()
        else:
            err = rthread.tlfield_rpy_lasterror.getraw()
        # careful, getraw() overwrites GetLastError.
        # We must assign it with _SetLastError() as the last
        # operation, i.e. after the errno handling.
        rwin32._SetLastError(err)

@specialize.call_location()
def _errno_after(save_err):
    if _WIN32:
        if save_err & rffi.RFFI_SAVE_LASTERROR:
            err = rwin32._GetLastError()
            # careful, setraw() overwrites GetLastError.
            # We must read it first, before the errno handling.
            if save_err & rffi.RFFI_ALT_ERRNO:
                rthread.tlfield_alt_lasterror.setraw(err)
            else:
                rthread.tlfield_rpy_lasterror.setraw(err)
        elif save_err & rffi.RFFI_SAVE_WSALASTERROR:
            from rpython.rlib import _rsocket_rffi
            err = _rsocket_rffi._WSAGetLastError()
            if save_err & rffi.RFFI_ALT_ERRNO:
                rthread.tlfield_alt_lasterror.setraw(err)
            else:
                rthread.tlfield_rpy_lasterror.setraw(err)
    if save_err & rffi.RFFI_SAVE_ERRNO:
        if save_err & rffi.RFFI_ALT_ERRNO:
            rthread.tlfield_alt_errno.setraw(_get_errno())
        else:
            rthread.tlfield_rpy_errno.setraw(_get_errno())
            # ^^^ keep fork() up-to-date too, below


if os.name == 'nt':
    is_valid_fd = jit.dont_look_inside(rffi.llexternal(
        "_PyVerify_fd", [rffi.INT], rffi.INT,
        compilation_info=errno_eci,
        ))
    @enforceargs(int)
    def validate_fd(fd):
        if not is_valid_fd(fd):
            from errno import EBADF
            raise OSError(EBADF, 'Bad file descriptor')
else:
    def is_valid_fd(fd):
        return 1

    @enforceargs(int)
    def validate_fd(fd):
        pass

def closerange(fd_low, fd_high):
    # this behaves like os.closerange() from Python 2.6.
    for fd in xrange(fd_low, fd_high):
        try:
            if is_valid_fd(fd):
                os.close(fd)
        except OSError:
            pass

if _WIN32:
    includes = ['io.h', 'sys/utime.h', 'sys/types.h', 'process.h']
    libraries = []
else:
    if sys.platform.startswith(('darwin', 'netbsd', 'openbsd')):
        _ptyh = 'util.h'
    elif sys.platform.startswith('freebsd'):
        _ptyh = 'libutil.h'
    else:
        _ptyh = 'pty.h'
    includes = ['unistd.h',  'sys/types.h', 'sys/wait.h',
                'utime.h', 'sys/time.h', 'sys/times.h',
                'grp.h', 'dirent.h', 'sys/stat.h', 'fcntl.h',
                'signal.h', 'sys/utsname.h', _ptyh]
    libraries = ['util']
eci = ExternalCompilationInfo(
    includes=includes,
    libraries=libraries,
)

class CConfig:
    _compilation_info_ = eci
    SEEK_SET = rffi_platform.DefinedConstantInteger('SEEK_SET')
    SEEK_CUR = rffi_platform.DefinedConstantInteger('SEEK_CUR')
    SEEK_END = rffi_platform.DefinedConstantInteger('SEEK_END')
    OFF_T_SIZE = rffi_platform.SizeOf('off_t')

    HAVE_UTIMES = rffi_platform.Has('utimes')
    UTIMBUF = rffi_platform.Struct('struct %sutimbuf' % UNDERSCORE_ON_WIN32,
                                   [('actime', rffi.INT),
                                    ('modtime', rffi.INT)])
    if not _WIN32:
        UID_T = rffi_platform.SimpleType('uid_t', rffi.UINT)
        GID_T = rffi_platform.SimpleType('gid_t', rffi.UINT)
        CLOCK_T = rffi_platform.SimpleType('clock_t', rffi.INT)

        TMS = rffi_platform.Struct(
            'struct tms', [('tms_utime', rffi.INT),
                           ('tms_stime', rffi.INT),
                           ('tms_cutime', rffi.INT),
                           ('tms_cstime', rffi.INT)])

    GETPGRP_HAVE_ARG = rffi_platform.Has("getpgrp(0)")
    SETPGRP_HAVE_ARG = rffi_platform.Has("setpgrp(0, 0)")

config = rffi_platform.configure(CConfig)
globals().update(config)

def external(name, args, result, compilation_info=eci, **kwds):
    return rffi.llexternal(name, args, result,
                           compilation_info=compilation_info, **kwds)

# For now we require off_t to be the same size as LONGLONG, which is the
# interface required by callers of functions that thake an argument of type
# off_t.
if not _WIN32:
    assert OFF_T_SIZE == rffi.sizeof(rffi.LONGLONG)

c_dup = external(UNDERSCORE_ON_WIN32 + 'dup', [rffi.INT], rffi.INT,
                 save_err=rffi.RFFI_SAVE_ERRNO)
c_dup2 = external(UNDERSCORE_ON_WIN32 + 'dup2', [rffi.INT, rffi.INT], rffi.INT,
                  save_err=rffi.RFFI_SAVE_ERRNO)
c_open = external(UNDERSCORE_ON_WIN32 + 'open',
                  [rffi.CCHARP, rffi.INT, rffi.MODE_T], rffi.INT,
                  save_err=rffi.RFFI_SAVE_ERRNO)

# Win32 Unicode functions
c_wopen = external(UNDERSCORE_ON_WIN32 + 'wopen',
                   [rffi.CWCHARP, rffi.INT, rffi.MODE_T], rffi.INT,
                   save_err=rffi.RFFI_SAVE_ERRNO)

#___________________________________________________________________
# Wrappers around posix functions, that accept either strings, or
# instances with a "as_bytes()" method.
# - pypy.modules.posix.interp_posix passes an object containing a unicode path
#   which can encode itself with sys.filesystemencoding.
# - but rpython.rtyper.module.ll_os.py on Windows will replace these functions
#   with other wrappers that directly handle unicode strings.
@specialize.argtype(0)
@signature(types.any(), returns=s_Str0)
def _as_bytes(path):
    assert path is not None
    if isinstance(path, str):
        return path
    elif isinstance(path, unicode):
        # This never happens in PyPy's Python interpreter!
        # Only in raw RPython code that uses unicode strings.
        # We implement python2 behavior: silently convert to ascii.
        return path.encode('ascii')
    else:
        return path.as_bytes()

@specialize.argtype(0)
def _as_bytes0(path):
    """Crashes translation if the path contains NUL characters."""
    res = _as_bytes(path)
    rstring.check_str0(res)
    return res

@specialize.argtype(0)
def _as_unicode(path):
    assert path is not None
    if isinstance(path, unicode):
        return path
    else:
        return path.as_unicode()

@specialize.argtype(0)
def _as_unicode0(path):
    """Crashes translation if the path contains NUL characters."""
    res = _as_unicode(path)
    rstring.check_str0(res)
    return res

@specialize.argtype(0, 1)
def putenv(name, value):
    os.environ[_as_bytes(name)] = _as_bytes(value)

@specialize.argtype(0)
def unsetenv(name):
    del os.environ[_as_bytes(name)]

#___________________________________________________________________
# Implementation of many posix functions.
# They usually check the return value and raise an (RPython) OSError
# with errno.

def replace_os_function(name):
    func = getattr(os, name, None)
    if func is None:
        return lambda f: f
    return register_replacement_for(
        func,
        sandboxed_name='ll_os.ll_os_%s' % name)

@specialize.arg(0)
def handle_posix_error(name, result):
    result = widen(result)
    if result < 0:
        raise OSError(get_saved_errno(), '%s failed' % name)
    return result

@replace_os_function('dup')
def dup(fd):
    validate_fd(fd)
    return handle_posix_error('dup', c_dup(fd))

@replace_os_function('dup2')
def dup2(fd, newfd):
    validate_fd(fd)
    handle_posix_error('dup2', c_dup2(fd, newfd))

#___________________________________________________________________

@replace_os_function('open')
@specialize.argtype(0)
@enforceargs(NOT_CONSTANT, int, int, typecheck=False)
def open(path, flags, mode):
    if _prefer_unicode(path):
        fd = c_wopen(_as_unicode0(path), flags, mode)
    else:
        fd = c_open(_as_bytes0(path), flags, mode)
    return handle_posix_error('open', fd)

c_read = external(UNDERSCORE_ON_WIN32 + 'read',
                  [rffi.INT, rffi.VOIDP, rffi.SIZE_T], rffi.SSIZE_T,
                  save_err=rffi.RFFI_SAVE_ERRNO)
c_write = external(UNDERSCORE_ON_WIN32 + 'write',
                   [rffi.INT, rffi.VOIDP, rffi.SIZE_T], rffi.SSIZE_T,
                   save_err=rffi.RFFI_SAVE_ERRNO)
c_close = external(UNDERSCORE_ON_WIN32 + 'close', [rffi.INT], rffi.INT,
                   releasegil=False, save_err=rffi.RFFI_SAVE_ERRNO)

@replace_os_function('read')
@enforceargs(int, int)
def read(fd, count):
    if count < 0:
        raise OSError(errno.EINVAL, None)
    validate_fd(fd)
    with rffi.scoped_alloc_buffer(count) as buf:
        void_buf = rffi.cast(rffi.VOIDP, buf.raw)
        got = handle_posix_error('read', c_read(fd, void_buf, count))
        return buf.str(got)

@replace_os_function('write')
@enforceargs(int, None)
def write(fd, data):
    count = len(data)
    validate_fd(fd)
    with rffi.scoped_nonmovingbuffer(data) as buf:
        return handle_posix_error('write', c_write(fd, buf, count))

@replace_os_function('close')
def close(fd):
    validate_fd(fd)
    handle_posix_error('close', c_close(fd))

c_lseek = external('_lseeki64' if _WIN32 else 'lseek',
                   [rffi.INT, rffi.LONGLONG, rffi.INT], rffi.LONGLONG,
                   macro=_MACRO_ON_POSIX, save_err=rffi.RFFI_SAVE_ERRNO)

@replace_os_function('lseek')
def lseek(fd, pos, how):
    validate_fd(fd)
    if SEEK_SET is not None:
        if how == 0:
            how = SEEK_SET
        elif how == 1:
            how = SEEK_CUR
        elif how == 2:
            how = SEEK_END
    return handle_posix_error('lseek', c_lseek(fd, pos, how))

c_ftruncate = external('ftruncate', [rffi.INT, rffi.LONGLONG], rffi.INT,
                       macro=_MACRO_ON_POSIX, save_err=rffi.RFFI_SAVE_ERRNO)
c_fsync = external('fsync' if not _WIN32 else '_commit', [rffi.INT], rffi.INT,
                   save_err=rffi.RFFI_SAVE_ERRNO)
c_fdatasync = external('fdatasync', [rffi.INT], rffi.INT,
                       save_err=rffi.RFFI_SAVE_ERRNO)

@replace_os_function('ftruncate')
def ftruncate(fd, length):
    validate_fd(fd)
    handle_posix_error('ftruncate', c_ftruncate(fd, length))

@replace_os_function('fsync')
def fsync(fd):
    validate_fd(fd)
    handle_posix_error('fsync', c_fsync(fd))

@replace_os_function('fdatasync')
def fdatasync(fd):
    validate_fd(fd)
    handle_posix_error('fdatasync', c_fdatasync(fd))

#___________________________________________________________________

c_chdir = external('chdir', [rffi.CCHARP], rffi.INT,
                   save_err=rffi.RFFI_SAVE_ERRNO)
c_fchdir = external('fchdir', [rffi.INT], rffi.INT,
                    save_err=rffi.RFFI_SAVE_ERRNO)
c_access = external(UNDERSCORE_ON_WIN32 + 'access',
                    [rffi.CCHARP, rffi.INT], rffi.INT)
c_waccess = external(UNDERSCORE_ON_WIN32 + 'waccess',
                     [rffi.CWCHARP, rffi.INT], rffi.INT)

@replace_os_function('chdir')
@specialize.argtype(0)
def chdir(path):
    if not _WIN32:
        handle_posix_error('chdir', c_chdir(_as_bytes0(path)))
    else:
        traits = _preferred_traits(path)
        win32traits = make_win32_traits(traits)
        path = traits.as_str0(path)

        # This is a reimplementation of the C library's chdir
        # function, but one that produces Win32 errors instead of DOS
        # error codes.
        # chdir is essentially a wrapper around SetCurrentDirectory;
        # however, it also needs to set "magic" environment variables
        # indicating the per-drive current directory, which are of the
        # form =<drive>:
        if not win32traits.SetCurrentDirectory(path):
            raise rwin32.lastSavedWindowsError()
        MAX_PATH = rwin32.MAX_PATH
        assert MAX_PATH > 0

        with traits.scoped_alloc_buffer(MAX_PATH) as path:
            res = win32traits.GetCurrentDirectory(MAX_PATH + 1, path.raw)
            if not res:
                raise rwin32.lastSavedWindowsError()
            res = rffi.cast(lltype.Signed, res)
            assert res > 0
            if res <= MAX_PATH + 1:
                new_path = path.str(res)
            else:
                with traits.scoped_alloc_buffer(res) as path:
                    res = win32traits.GetCurrentDirectory(res, path.raw)
                    if not res:
                        raise rwin32.lastSavedWindowsError()
                    res = rffi.cast(lltype.Signed, res)
                    assert res > 0
                    new_path = path.str(res)
        if traits.str is unicode:
            if new_path[0] == u'\\' or new_path[0] == u'/':  # UNC path
                return
            magic_envvar = u'=' + new_path[0] + u':'
        else:
            if new_path[0] == '\\' or new_path[0] == '/':  # UNC path
                return
            magic_envvar = '=' + new_path[0] + ':'
        if not win32traits.SetEnvironmentVariable(magic_envvar, new_path):
            raise rwin32.lastSavedWindowsError()

@replace_os_function('fchdir')
def fchdir(fd):
    validate_fd(fd)
    handle_posix_error('fchdir', c_fchdir(fd))

@replace_os_function('access')
@specialize.argtype(0)
def access(path, mode):
    if _WIN32:
        # All files are executable on Windows
        mode = mode & ~os.X_OK
    if _prefer_unicode(path):
        error = c_waccess(_as_unicode0(path), mode)
    else:
        error = c_access(_as_bytes0(path), mode)
    return error == 0

# This Win32 function is not exposed via os, but needed to get a
# correct implementation of os.path.abspath.
@specialize.argtype(0)
def getfullpathname(path):
    length = rwin32.MAX_PATH + 1
    traits = _preferred_traits(path)
    win32traits = make_win32_traits(traits)
    with traits.scoped_alloc_buffer(length) as buf:
        res = win32traits.GetFullPathName(
            traits.as_str0(path), rffi.cast(rwin32.DWORD, length),
            buf.raw, lltype.nullptr(win32traits.LPSTRP.TO))
        if res == 0:
            raise rwin32.lastSavedWindowsError("_getfullpathname failed")
        result = buf.str(intmask(res))
        assert result is not None
        result = rstring.assert_str0(result)
        return result

c_getcwd = external(UNDERSCORE_ON_WIN32 + 'getcwd',
                    [rffi.CCHARP, rffi.SIZE_T], rffi.CCHARP,
                    save_err=rffi.RFFI_SAVE_ERRNO)
c_wgetcwd = external(UNDERSCORE_ON_WIN32 + 'wgetcwd',
                     [rffi.CWCHARP, rffi.SIZE_T], rffi.CWCHARP,
                     save_err=rffi.RFFI_SAVE_ERRNO)

@replace_os_function('getcwd')
def getcwd():
    bufsize = 256
    while True:
        buf = lltype.malloc(rffi.CCHARP.TO, bufsize, flavor='raw')
        res = c_getcwd(buf, bufsize)
        if res:
            break   # ok
        error = get_saved_errno()
        lltype.free(buf, flavor='raw')
        if error != errno.ERANGE:
            raise OSError(error, "getcwd failed")
        # else try again with a larger buffer, up to some sane limit
        bufsize *= 4
        if bufsize > 1024*1024:  # xxx hard-coded upper limit
            raise OSError(error, "getcwd result too large")
    result = rffi.charp2str(res)
    lltype.free(buf, flavor='raw')
    return result

@replace_os_function('getcwdu')
def getcwdu():
    bufsize = 256
    while True:
        buf = lltype.malloc(rffi.CWCHARP.TO, bufsize, flavor='raw')
        res = c_wgetcwd(buf, bufsize)
        if res:
            break   # ok
        error = get_saved_errno()
        lltype.free(buf, flavor='raw')
        if error != errno.ERANGE:
            raise OSError(error, "getcwd failed")
        # else try again with a larger buffer, up to some sane limit
        bufsize *= 4
        if bufsize > 1024*1024:  # xxx hard-coded upper limit
            raise OSError(error, "getcwd result too large")
    result = rffi.wcharp2unicode(res)
    lltype.free(buf, flavor='raw')
    return result

if not _WIN32:
    class CConfig:
        _compilation_info_ = eci
        DIRENT = rffi_platform.Struct('struct dirent',
            [('d_name', lltype.FixedSizeArray(rffi.CHAR, 1))])

    DIRP = rffi.COpaquePtr('DIR')
    config = rffi_platform.configure(CConfig)
    DIRENT = config['DIRENT']
    DIRENTP = lltype.Ptr(DIRENT)
    c_opendir = external('opendir',
        [rffi.CCHARP], DIRP, save_err=rffi.RFFI_SAVE_ERRNO)
    c_fdopendir = external('fdopendir',
        [rffi.INT], DIRP, save_err=rffi.RFFI_SAVE_ERRNO)
    # XXX macro=True is hack to make sure we get the correct kind of
    # dirent struct (which depends on defines)
    c_readdir = external('readdir', [DIRP], DIRENTP,
                         macro=True, save_err=rffi.RFFI_FULL_ERRNO_ZERO)
    c_closedir = external('closedir', [DIRP], rffi.INT)

def _listdir(dirp):
    result = []
    while True:
        direntp = c_readdir(dirp)
        if not direntp:
            error = get_saved_errno()
            break
        namep = rffi.cast(rffi.CCHARP, direntp.c_d_name)
        name = rffi.charp2str(namep)
        if name != '.' and name != '..':
            result.append(name)
    c_closedir(dirp)
    if error:
        raise OSError(error, "readdir failed")
    return result

def fdlistdir(dirfd):
    """
    Like listdir(), except that the directory is specified as an open
    file descriptor.

    Note: fdlistdir() closes the file descriptor.
    """
    dirp = c_fdopendir(dirfd)
    if not dirp:
        raise OSError(get_saved_errno(), "opendir failed")
    return _listdir(dirp)

@replace_os_function('listdir')
@specialize.argtype(0)
def listdir(path):
    if not _WIN32:
        path = _as_bytes0(path)
        dirp = c_opendir(path)
        if not dirp:
            raise OSError(get_saved_errno(), "opendir failed")
        return _listdir(dirp)
    else:  # _WIN32 case
        traits = _preferred_traits(path)
        win32traits = make_win32_traits(traits)
        path = traits.as_str0(path)

        if traits.str is unicode:
            if path and path[-1] not in (u'/', u'\\', u':'):
                path += u'/'
            mask = path + u'*.*'
        else:
            if path and path[-1] not in ('/', '\\', ':'):
                path += '/'
            mask = path + '*.*'

        filedata = lltype.malloc(win32traits.WIN32_FIND_DATA, flavor='raw')
        try:
            result = []
            hFindFile = win32traits.FindFirstFile(mask, filedata)
            if hFindFile == rwin32.INVALID_HANDLE_VALUE:
                error = rwin32.GetLastError_saved()
                if error == win32traits.ERROR_FILE_NOT_FOUND:
                    return result
                else:
                    raise WindowsError(error,  "FindFirstFile failed")
            while True:
                name = traits.charp2str(rffi.cast(traits.CCHARP,
                                                  filedata.c_cFileName))
                if traits.str is unicode:
                    if not (name == u"." or name == u".."):
                        result.append(name)
                else:
                    if not (name == "." or name == ".."):
                        result.append(name)
                if not win32traits.FindNextFile(hFindFile, filedata):
                    break
            # FindNextFile sets error to ERROR_NO_MORE_FILES if
            # it got to the end of the directory
            error = rwin32.GetLastError_saved()
            win32traits.FindClose(hFindFile)
            if error == win32traits.ERROR_NO_MORE_FILES:
                return result
            else:
                raise WindowsError(error,  "FindNextFile failed")
        finally:
            lltype.free(filedata, flavor='raw')

#___________________________________________________________________

c_execv = external('execv', [rffi.CCHARP, rffi.CCHARPP], rffi.INT,
                   save_err=rffi.RFFI_SAVE_ERRNO)
c_execve = external('execve',
                    [rffi.CCHARP, rffi.CCHARPP, rffi.CCHARPP], rffi.INT,
                    save_err=rffi.RFFI_SAVE_ERRNO)
c_spawnv = external(UNDERSCORE_ON_WIN32 + 'spawnv',
                    [rffi.INT, rffi.CCHARP, rffi.CCHARPP], rffi.INT,
                    save_err=rffi.RFFI_SAVE_ERRNO)
c_spawnve = external(UNDERSCORE_ON_WIN32 + 'spawnve',
                    [rffi.INT, rffi.CCHARP, rffi.CCHARPP, rffi.CCHARPP],
                     rffi.INT,
                     save_err=rffi.RFFI_SAVE_ERRNO)

@replace_os_function('execv')
def execv(path, args):
    rstring.check_str0(path)
    # This list conversion already takes care of NUL bytes.
    l_args = rffi.ll_liststr2charpp(args)
    c_execv(path, l_args)
    rffi.free_charpp(l_args)
    raise OSError(get_saved_errno(), "execv failed")

@replace_os_function('execve')
def execve(path, args, env):
    envstrs = []
    for item in env.iteritems():
        envstr = "%s=%s" % item
        envstrs.append(envstr)

    rstring.check_str0(path)
    # This list conversion already takes care of NUL bytes.
    l_args = rffi.ll_liststr2charpp(args)
    l_env = rffi.ll_liststr2charpp(envstrs)
    c_execve(path, l_args, l_env)

    rffi.free_charpp(l_env)
    rffi.free_charpp(l_args)
    raise OSError(get_saved_errno(), "execve failed")

@replace_os_function('spawnv')
def spawnv(mode, path, args):
    rstring.check_str0(path)
    l_args = rffi.ll_liststr2charpp(args)
    childpid = c_spawnv(mode, path, l_args)
    rffi.free_charpp(l_args)
    return handle_posix_error('spawnv', childpid)

@replace_os_function('spawnve')
def spawnve(mode, path, args, env):
    envstrs = []
    for item in env.iteritems():
        envstrs.append("%s=%s" % item)
    rstring.check_str0(path)
    l_args = rffi.ll_liststr2charpp(args)
    l_env = rffi.ll_liststr2charpp(envstrs)
    childpid = c_spawnve(mode, path, l_args, l_env)
    rffi.free_charpp(l_env)
    rffi.free_charpp(l_args)
    return handle_posix_error('spawnve', childpid)

c_fork = external('fork', [], rffi.PID_T, _nowrapper = True)
c_openpty = external('openpty',
                     [rffi.INTP, rffi.INTP, rffi.VOIDP, rffi.VOIDP, rffi.VOIDP],
                     rffi.INT,
                     save_err=rffi.RFFI_SAVE_ERRNO)
c_forkpty = external('forkpty',
                     [rffi.INTP, rffi.VOIDP, rffi.VOIDP, rffi.VOIDP],
                     rffi.PID_T, _nowrapper = True)

@replace_os_function('fork')
@jit.dont_look_inside
def fork():
    # NB. keep forkpty() up-to-date, too
    # lots of custom logic here, to do things in the right order
    ofs = debug.debug_offset()
    opaqueaddr = rthread.gc_thread_before_fork()
    childpid = c_fork()
    errno = _get_errno()
    rthread.gc_thread_after_fork(childpid, opaqueaddr)
    rthread.tlfield_rpy_errno.setraw(errno)
    childpid = handle_posix_error('fork', childpid)
    if childpid == 0:
        debug.debug_forked(ofs)
    return childpid

@replace_os_function('openpty')
@jit.dont_look_inside
def openpty():
    master_p = lltype.malloc(rffi.INTP.TO, 1, flavor='raw')
    slave_p = lltype.malloc(rffi.INTP.TO, 1, flavor='raw')
    try:
        handle_posix_error(
            'openpty', c_openpty(master_p, slave_p, None, None, None))
        return (widen(master_p[0]), widen(slave_p[0]))
    finally:
        lltype.free(master_p, flavor='raw')
        lltype.free(slave_p, flavor='raw')

@replace_os_function('forkpty')
@jit.dont_look_inside
def forkpty():
    master_p = lltype.malloc(rffi.INTP.TO, 1, flavor='raw')
    master_p[0] = rffi.cast(rffi.INT, -1)
    null = lltype.nullptr(rffi.VOIDP.TO)
    try:
        ofs = debug.debug_offset()
        opaqueaddr = rthread.gc_thread_before_fork()
        childpid = c_forkpty(master_p, null, null, null)
        errno = _get_errno()
        rthread.gc_thread_after_fork(childpid, opaqueaddr)
        rthread.tlfield_rpy_errno.setraw(errno)
        childpid = handle_posix_error('forkpty', childpid)
        if childpid == 0:
            debug.debug_forked(ofs)
        return (childpid, master_p[0])
    finally:
        lltype.free(master_p, flavor='raw')

if _WIN32:
    # emulate waitpid() with the _cwait() of Microsoft's compiler
    c__cwait = external('_cwait',
                        [rffi.INTP, rffi.PID_T, rffi.INT], rffi.PID_T,
                        save_err=rffi.RFFI_SAVE_ERRNO)
    @jit.dont_look_inside
    def c_waitpid(pid, status_p, options):
        result = c__cwait(status_p, pid, options)
        # shift the status left a byte so this is more
        # like the POSIX waitpid
        status_p[0] = rffi.cast(rffi.INT, widen(status_p[0]) << 8)
        return result
elif _CYGWIN:
    c_waitpid = external('cygwin_waitpid',
                         [rffi.PID_T, rffi.INTP, rffi.INT], rffi.PID_T,
                         save_err=rffi.RFFI_SAVE_ERRNO)
else:
    c_waitpid = external('waitpid',
                         [rffi.PID_T, rffi.INTP, rffi.INT], rffi.PID_T,
                         save_err=rffi.RFFI_SAVE_ERRNO)

@replace_os_function('waitpid')
def waitpid(pid, options):
    status_p = lltype.malloc(rffi.INTP.TO, 1, flavor='raw')
    status_p[0] = rffi.cast(rffi.INT, 0)
    try:
        result = handle_posix_error('waitpid',
                                    c_waitpid(pid, status_p, options))
        status = widen(status_p[0])
        return (result, status)
    finally:
        lltype.free(status_p, flavor='raw')

def _make_waitmacro(name):
    # note that rffi.INT as first parameter type is intentional.
    # on s390x providing a lltype.Signed as param type, the
    # macro wrapper function will always return 0
    # reason: legacy code required a union wait. see
    # https://sourceware.org/bugzilla/show_bug.cgi?id=19613
    # for more details. If this get's fixed we can use lltype.Signed
    # again.  (The exact same issue occurs on ppc64 big-endian.)
    c_func = external(name, [rffi.INT], lltype.Signed,
                      macro=_MACRO_ON_POSIX)
    returning_int = name in ('WEXITSTATUS', 'WSTOPSIG', 'WTERMSIG')

    @replace_os_function(name)
    @func_renamer(name)
    def _waitmacro(status):
        if returning_int:
            return c_func(status)
        else:
            return bool(c_func(status))

WAIT_MACROS = ['WCOREDUMP', 'WIFCONTINUED', 'WIFSTOPPED',
               'WIFSIGNALED', 'WIFEXITED',
               'WEXITSTATUS', 'WSTOPSIG', 'WTERMSIG']
for name in WAIT_MACROS:
    _make_waitmacro(name)

#___________________________________________________________________

c_getlogin = external('getlogin', [], rffi.CCHARP,
                      releasegil=False, save_err=rffi.RFFI_SAVE_ERRNO)
c_getloadavg = external('getloadavg',
                        [rffi.CArrayPtr(lltype.Float), rffi.INT], rffi.INT)

@replace_os_function('getlogin')
def getlogin():
    result = c_getlogin()
    if not result:
        raise OSError(get_saved_errno(), "getlogin failed")
    return rffi.charp2str(result)

@replace_os_function('getloadavg')
def getloadavg():
    load = lltype.malloc(rffi.CArrayPtr(lltype.Float).TO, 3, flavor='raw')
    try:
        r = c_getloadavg(load, 3)
        if r != 3:
            raise OSError
        return (load[0], load[1], load[2])
    finally:
        lltype.free(load, flavor='raw')

#___________________________________________________________________

c_readlink = external('readlink',
                      [rffi.CCHARP, rffi.CCHARP, rffi.SIZE_T], rffi.SSIZE_T,
                      save_err=rffi.RFFI_SAVE_ERRNO)

@replace_os_function('readlink')
def readlink(path):
    path = _as_bytes0(path)
    bufsize = 1023
    while True:
        buf = lltype.malloc(rffi.CCHARP.TO, bufsize, flavor='raw')
        res = widen(c_readlink(path, buf, bufsize))
        if res < 0:
            lltype.free(buf, flavor='raw')
            error = get_saved_errno()    # failed
            raise OSError(error, "readlink failed")
        elif res < bufsize:
            break                       # ok
        else:
            # buf too small, try again with a larger buffer
            lltype.free(buf, flavor='raw')
            bufsize *= 4
    # convert the result to a string
    result = rffi.charp2strn(buf, res)
    lltype.free(buf, flavor='raw')
    return result

c_isatty = external(UNDERSCORE_ON_WIN32 + 'isatty', [rffi.INT], rffi.INT)

@replace_os_function('isatty')
def isatty(fd):
    if not is_valid_fd(fd):
        return False
    return c_isatty(fd) != 0

c_ttyname = external('ttyname', [lltype.Signed], rffi.CCHARP,
                     releasegil=False,
                     save_err=rffi.RFFI_SAVE_ERRNO)

@replace_os_function('ttyname')
def ttyname(fd):
    l_name = c_ttyname(fd)
    if not l_name:
        raise OSError(get_saved_errno(), "ttyname raised")
    return rffi.charp2str(l_name)

c_strerror = external('strerror', [rffi.INT], rffi.CCHARP,
                      releasegil=False)

@replace_os_function('strerror')
def strerror(errnum):
    res = c_strerror(errnum)
    if not res:
        raise ValueError("os_strerror failed")
    return rffi.charp2str(res)

c_system = external('system', [rffi.CCHARP], rffi.INT)

@replace_os_function('system')
def system(command):
    return widen(c_system(command))

c_unlink = external('unlink', [rffi.CCHARP], rffi.INT,
                    save_err=rffi.RFFI_SAVE_ERRNO)
c_mkdir = external('mkdir', [rffi.CCHARP, rffi.MODE_T], rffi.INT,
                   save_err=rffi.RFFI_SAVE_ERRNO)
c_rmdir = external(UNDERSCORE_ON_WIN32 + 'rmdir', [rffi.CCHARP], rffi.INT,
                   save_err=rffi.RFFI_SAVE_ERRNO)
c_wrmdir = external(UNDERSCORE_ON_WIN32 + 'wrmdir', [rffi.CWCHARP], rffi.INT,
                    save_err=rffi.RFFI_SAVE_ERRNO)

@replace_os_function('unlink')
@specialize.argtype(0)
def unlink(path):
    if not _WIN32:
        handle_posix_error('unlink', c_unlink(_as_bytes0(path)))
    else:
        traits = _preferred_traits(path)
        win32traits = make_win32_traits(traits)
        if not win32traits.DeleteFile(traits.as_str0(path)):
            raise rwin32.lastSavedWindowsError()

@replace_os_function('mkdir')
@specialize.argtype(0)
def mkdir(path, mode=0o777):
    if not _WIN32:
        handle_posix_error('mkdir', c_mkdir(_as_bytes0(path), mode))
    else:
        traits = _preferred_traits(path)
        win32traits = make_win32_traits(traits)
        if not win32traits.CreateDirectory(traits.as_str0(path), None):
            raise rwin32.lastSavedWindowsError()

@replace_os_function('rmdir')
@specialize.argtype(0)
@jit.dont_look_inside
def rmdir(path):
    if _prefer_unicode(path):
        handle_posix_error('wrmdir', c_wrmdir(_as_unicode0(path)))
    else:
        handle_posix_error('rmdir', c_rmdir(_as_bytes0(path)))

c_chmod = external('chmod', [rffi.CCHARP, rffi.MODE_T], rffi.INT,
                   save_err=rffi.RFFI_SAVE_ERRNO)
c_fchmod = external('fchmod', [rffi.INT, rffi.MODE_T], rffi.INT,
                    save_err=rffi.RFFI_SAVE_ERRNO,)
c_rename = external('rename', [rffi.CCHARP, rffi.CCHARP], rffi.INT,
                    save_err=rffi.RFFI_SAVE_ERRNO)

@replace_os_function('chmod')
@specialize.argtype(0)
def chmod(path, mode):
    if not _WIN32:
        handle_posix_error('chmod', c_chmod(_as_bytes0(path), mode))
    else:
        traits = _preferred_traits(path)
        win32traits = make_win32_traits(traits)
        path = traits.as_str0(path)
        attr = win32traits.GetFileAttributes(path)
        if attr == win32traits.INVALID_FILE_ATTRIBUTES:
            raise rwin32.lastSavedWindowsError()
        if mode & 0200: # _S_IWRITE
            attr &= ~win32traits.FILE_ATTRIBUTE_READONLY
        else:
            attr |= win32traits.FILE_ATTRIBUTE_READONLY
        if not win32traits.SetFileAttributes(path, attr):
            raise rwin32.lastSavedWindowsError()

@replace_os_function('fchmod')
def fchmod(fd, mode):
    handle_posix_error('fchmod', c_fchmod(fd, mode))

@replace_os_function('rename')
@specialize.argtype(0, 1)
def rename(path1, path2):
    if not _WIN32:
        handle_posix_error('rename',
                           c_rename(_as_bytes0(path1), _as_bytes0(path2)))
    else:
        traits = _preferred_traits(path1)
        win32traits = make_win32_traits(traits)
        path1 = traits.as_str0(path1)
        path2 = traits.as_str0(path2)
        if not win32traits.MoveFileEx(path1, path2, 0):
            raise rwin32.lastSavedWindowsError()

@specialize.argtype(0, 1)
def replace(path1, path2):
    if _WIN32:
        traits = _preferred_traits(path1)
        win32traits = make_win32_traits(traits)
        path1 = traits.as_str0(path1)
        path2 = traits.as_str0(path2)
        ret = win32traits.MoveFileEx(path1, path2,
                     win32traits.MOVEFILE_REPLACE_EXISTING)
        if not ret:
            raise rwin32.lastSavedWindowsError()
    else:
        ret = rename(path1, path2)
    return ret

#___________________________________________________________________

c_mkfifo = external('mkfifo', [rffi.CCHARP, rffi.MODE_T], rffi.INT,
                    save_err=rffi.RFFI_SAVE_ERRNO)
c_mknod = external('mknod', [rffi.CCHARP, rffi.MODE_T, rffi.INT], rffi.INT,
#                                           # xxx: actually ^^^ dev_t
                   macro=_MACRO_ON_POSIX, save_err=rffi.RFFI_SAVE_ERRNO)

@replace_os_function('mkfifo')
@specialize.argtype(0)
def mkfifo(path, mode):
    handle_posix_error('mkfifo', c_mkfifo(_as_bytes0(path), mode))

@replace_os_function('mknod')
@specialize.argtype(0)
def mknod(path, mode, dev):
    handle_posix_error('mknod', c_mknod(_as_bytes0(path), mode, dev))

if _WIN32:
    CreatePipe = external('CreatePipe', [rwin32.LPHANDLE,
                                         rwin32.LPHANDLE,
                                         rffi.VOIDP,
                                         rwin32.DWORD],
                          rwin32.BOOL)
    c_open_osfhandle = external('_open_osfhandle', [rffi.INTPTR_T,
                                                    rffi.INT],
                                rffi.INT)
else:
    INT_ARRAY_P = rffi.CArrayPtr(rffi.INT)
    c_pipe = external('pipe', [INT_ARRAY_P], rffi.INT,
                      save_err=rffi.RFFI_SAVE_ERRNO)

@replace_os_function('pipe')
def pipe():
    if _WIN32:
        pread  = lltype.malloc(rwin32.LPHANDLE.TO, 1, flavor='raw')
        pwrite = lltype.malloc(rwin32.LPHANDLE.TO, 1, flavor='raw')
        try:
            if not CreatePipe(
                    pread, pwrite, lltype.nullptr(rffi.VOIDP.TO), 0):
                raise WindowsError(rwin32.GetLastError_saved(),
                                   "CreatePipe failed")
            hread = rffi.cast(rffi.INTPTR_T, pread[0])
            hwrite = rffi.cast(rffi.INTPTR_T, pwrite[0])
        finally:
            lltype.free(pwrite, flavor='raw')
            lltype.free(pread, flavor='raw')
        fdread = c_open_osfhandle(hread, 0)
        fdwrite = c_open_osfhandle(hwrite, 1)
        return (fdread, fdwrite)
    else:
        filedes = lltype.malloc(INT_ARRAY_P.TO, 2, flavor='raw')
        try:
            handle_posix_error('pipe', c_pipe(filedes))
            return (widen(filedes[0]), widen(filedes[1]))
        finally:
            lltype.free(filedes, flavor='raw')

c_link = external('link', [rffi.CCHARP, rffi.CCHARP], rffi.INT,
                  save_err=rffi.RFFI_SAVE_ERRNO,)
c_symlink = external('symlink', [rffi.CCHARP, rffi.CCHARP], rffi.INT,
                     save_err=rffi.RFFI_SAVE_ERRNO)

#___________________________________________________________________

@replace_os_function('link')
@specialize.argtype(0, 1)
def link(oldpath, newpath):
    oldpath = _as_bytes0(oldpath)
    newpath = _as_bytes0(newpath)
    handle_posix_error('link', c_link(oldpath, newpath))

@replace_os_function('symlink')
@specialize.argtype(0, 1)
def symlink(oldpath, newpath):
    oldpath = _as_bytes0(oldpath)
    newpath = _as_bytes0(newpath)
    handle_posix_error('symlink', c_symlink(oldpath, newpath))

c_umask = external(UNDERSCORE_ON_WIN32 + 'umask', [rffi.MODE_T], rffi.MODE_T)

@replace_os_function('umask')
def umask(newmask):
    return widen(c_umask(newmask))

c_chown = external('chown', [rffi.CCHARP, rffi.INT, rffi.INT], rffi.INT,
                   save_err=rffi.RFFI_SAVE_ERRNO)
c_lchown = external('lchown', [rffi.CCHARP, rffi.INT, rffi.INT], rffi.INT,
                    save_err=rffi.RFFI_SAVE_ERRNO)
c_fchown = external('fchown', [rffi.INT, rffi.INT, rffi.INT], rffi.INT,
                    save_err=rffi.RFFI_SAVE_ERRNO)

@replace_os_function('chown')
def chown(path, uid, gid):
    handle_posix_error('chown', c_chown(path, uid, gid))

@replace_os_function('lchown')
def lchown(path, uid, gid):
    handle_posix_error('lchown', c_lchown(path, uid, gid))

@replace_os_function('fchown')
def fchown(fd, uid, gid):
    handle_posix_error('fchown', c_fchown(fd, uid, gid))

#___________________________________________________________________

UTIMBUFP = lltype.Ptr(UTIMBUF)
c_utime = external('utime', [rffi.CCHARP, UTIMBUFP], rffi.INT,
                   save_err=rffi.RFFI_SAVE_ERRNO)
if HAVE_UTIMES:
    class CConfig:
        _compilation_info_ = eci
        TIMEVAL = rffi_platform.Struct('struct timeval', [
            ('tv_sec', rffi.LONG),
            ('tv_usec', rffi.LONG)])
    config = rffi_platform.configure(CConfig)
    TIMEVAL = config['TIMEVAL']
    TIMEVAL2P = rffi.CArrayPtr(TIMEVAL)
    c_utimes = external('utimes', [rffi.CCHARP, TIMEVAL2P], rffi.INT,
                        save_err=rffi.RFFI_SAVE_ERRNO)

if _WIN32:
    from rpython.rlib import rwin32
    GetSystemTime = external(
        'GetSystemTime',
        [lltype.Ptr(rwin32.SYSTEMTIME)],
        lltype.Void,
        calling_conv='win',
        save_err=rffi.RFFI_SAVE_LASTERROR)

    SystemTimeToFileTime = external(
        'SystemTimeToFileTime',
        [lltype.Ptr(rwin32.SYSTEMTIME),
         lltype.Ptr(rwin32.FILETIME)],
        rwin32.BOOL,
        calling_conv='win',
        save_err=rffi.RFFI_SAVE_LASTERROR)

    SetFileTime = external(
        'SetFileTime',
        [rwin32.HANDLE,
         lltype.Ptr(rwin32.FILETIME),
         lltype.Ptr(rwin32.FILETIME),
         lltype.Ptr(rwin32.FILETIME)],
        rwin32.BOOL,
        calling_conv='win')


@replace_os_function('utime')
@specialize.argtype(0, 1)
def utime(path, times):
    if not _WIN32:
        path = _as_bytes0(path)
        if times is None:
            error = c_utime(path, lltype.nullptr(UTIMBUFP.TO))
        else:
            if HAVE_UTIMES:
                with lltype.scoped_alloc(TIMEVAL2P.TO, 2) as l_timeval2p:
                    times_to_timeval2p(times, l_timeval2p)
                    error = c_utimes(path, l_timeval2p)
            else:
                # we only have utime(), which does not allow
                # sub-second resolution
                actime, modtime = times
                l_utimbuf = lltype.malloc(UTIMBUFP.TO, flavor='raw')
                l_utimbuf.c_actime  = rffi.r_time_t(actime)
                l_utimbuf.c_modtime = rffi.r_time_t(modtime)
                error = c_utime(path, l_utimbuf)
                lltype.free(l_utimbuf, flavor='raw')
        handle_posix_error('utime', error)
    else:  # _WIN32 case
        from rpython.rlib.rwin32file import time_t_to_FILE_TIME
        traits = _preferred_traits(path)
        win32traits = make_win32_traits(traits)
        path = traits.as_str0(path)
        hFile = win32traits.CreateFile(path,
                           win32traits.FILE_WRITE_ATTRIBUTES, 0,
                           None, win32traits.OPEN_EXISTING,
                           win32traits.FILE_FLAG_BACKUP_SEMANTICS,
                           rwin32.NULL_HANDLE)
        if hFile == rwin32.INVALID_HANDLE_VALUE:
            raise rwin32.lastSavedWindowsError()
        ctime = lltype.nullptr(rwin32.FILETIME)
        atime = lltype.malloc(rwin32.FILETIME, flavor='raw')
        mtime = lltype.malloc(rwin32.FILETIME, flavor='raw')
        try:
            if times is None:
                now = lltype.malloc(rwin32.SYSTEMTIME, flavor='raw')
                try:
                    GetSystemTime(now)
                    if (not SystemTimeToFileTime(now, atime) or
                        not SystemTimeToFileTime(now, mtime)):
                        raise rwin32.lastSavedWindowsError()
                finally:
                    lltype.free(now, flavor='raw')
            else:
                actime, modtime = times
                time_t_to_FILE_TIME(actime, atime)
                time_t_to_FILE_TIME(modtime, mtime)
            if not SetFileTime(hFile, ctime, atime, mtime):
                raise rwin32.lastSavedWindowsError()
        finally:
            rwin32.CloseHandle(hFile)
            lltype.free(atime, flavor='raw')
            lltype.free(mtime, flavor='raw')

def times_to_timeval2p(times, l_timeval2p):
    actime, modtime = times
    _time_to_timeval(actime, l_timeval2p[0])
    _time_to_timeval(modtime, l_timeval2p[1])

def _time_to_timeval(t, l_timeval):
    import math
    fracpart, intpart = math.modf(t)
    rffi.setintfield(l_timeval, 'c_tv_sec', int(intpart))
    rffi.setintfield(l_timeval, 'c_tv_usec', int(fracpart * 1e6))

if not _WIN32:
    TMSP = lltype.Ptr(TMS)
    c_times = external('times', [TMSP], CLOCK_T,
                        save_err=rffi.RFFI_SAVE_ERRNO |
                                 rffi.RFFI_ZERO_ERRNO_BEFORE)

    # Here is a random extra platform parameter which is important.
    # Strictly speaking, this should probably be retrieved at runtime, not
    # at translation time.
    CLOCK_TICKS_PER_SECOND = float(os.sysconf('SC_CLK_TCK'))
else:
    GetCurrentProcess = external(
        'GetCurrentProcess', [],
        rwin32.HANDLE, calling_conv='win')
    GetProcessTimes = external(
        'GetProcessTimes', [
            rwin32.HANDLE,
            lltype.Ptr(rwin32.FILETIME), lltype.Ptr(rwin32.FILETIME),
            lltype.Ptr(rwin32.FILETIME), lltype.Ptr(rwin32.FILETIME)],
        rwin32.BOOL, calling_conv='win')

@replace_os_function('times')
def times():
    if not _WIN32:
        l_tmsbuf = lltype.malloc(TMSP.TO, flavor='raw')
        try:
            # note: times() can return a negative value (or even -1)
            # even if there is no error
            result = rffi.cast(lltype.Signed, c_times(l_tmsbuf))
            if result == -1:
                errno = get_saved_errno()
                if errno != 0:
                    raise OSError(errno, 'times() failed')
            return (
                rffi.cast(lltype.Signed, l_tmsbuf.c_tms_utime)
                                               / CLOCK_TICKS_PER_SECOND,
                rffi.cast(lltype.Signed, l_tmsbuf.c_tms_stime)
                                               / CLOCK_TICKS_PER_SECOND,
                rffi.cast(lltype.Signed, l_tmsbuf.c_tms_cutime)
                                               / CLOCK_TICKS_PER_SECOND,
                rffi.cast(lltype.Signed, l_tmsbuf.c_tms_cstime)
                                               / CLOCK_TICKS_PER_SECOND,
                result / CLOCK_TICKS_PER_SECOND)
        finally:
            lltype.free(l_tmsbuf, flavor='raw')
    else:
        pcreate = lltype.malloc(rwin32.FILETIME, flavor='raw')
        pexit   = lltype.malloc(rwin32.FILETIME, flavor='raw')
        pkernel = lltype.malloc(rwin32.FILETIME, flavor='raw')
        puser   = lltype.malloc(rwin32.FILETIME, flavor='raw')
        try:
            hProc = GetCurrentProcess()
            GetProcessTimes(hProc, pcreate, pexit, pkernel, puser)
            # The fields of a FILETIME structure are the hi and lo parts
            # of a 64-bit value expressed in 100 nanosecond units
            # (of course).
            return (
                rffi.cast(lltype.Signed, pkernel.c_dwHighDateTime) * 429.4967296 +
                rffi.cast(lltype.Signed, pkernel.c_dwLowDateTime) * 1E-7,
                rffi.cast(lltype.Signed, puser.c_dwHighDateTime) * 429.4967296 +
                rffi.cast(lltype.Signed, puser.c_dwLowDateTime) * 1E-7,
                0., 0., 0.)
        finally:
            lltype.free(puser,   flavor='raw')
            lltype.free(pkernel, flavor='raw')
            lltype.free(pexit,   flavor='raw')
            lltype.free(pcreate, flavor='raw')

c_kill = external('kill', [rffi.PID_T, rffi.INT], rffi.INT,
                  save_err=rffi.RFFI_SAVE_ERRNO)
c_killpg = external('killpg', [rffi.INT, rffi.INT], rffi.INT,
                    save_err=rffi.RFFI_SAVE_ERRNO)
c_exit = external('_exit', [rffi.INT], lltype.Void)
c_nice = external('nice', [rffi.INT], rffi.INT,
                  save_err=rffi.RFFI_FULL_ERRNO_ZERO)

@replace_os_function('kill')
def kill(pid, sig):
    if not _WIN32:
        return handle_posix_error('kill', c_kill(pid, sig))
    else:
        if sig == rwin32.CTRL_C_EVENT or sig == rwin32.CTRL_BREAK_EVENT:
            if rwin32.GenerateConsoleCtrlEvent(sig, pid) == 0:
                raise rwin32.lastSavedWindowsError(
                    'kill() failed generating event')
            return
        handle = rwin32.OpenProcess(rwin32.PROCESS_ALL_ACCESS, False, pid)
        if not handle:
            raise rwin32.lastSavedWindowsError('kill() failed opening process')
        try:
            if rwin32.TerminateProcess(handle, sig) == 0:
                raise rwin32.lastSavedWindowsError(
                    'kill() failed to terminate process')
        finally:
            rwin32.CloseHandle(handle)

@replace_os_function('killpg')
def killpg(pgrp, sig):
    return handle_posix_error('killpg', c_killpg(pgrp, sig))

@replace_os_function('_exit')
@jit.dont_look_inside
def exit(status):
    debug.debug_flush()
    c_exit(status)

@replace_os_function('nice')
def nice(inc):
    # Assume that the system provides a standard-compliant version
    # of nice() that returns the new priority.  Nowadays, FreeBSD
    # might be the last major non-compliant system (xxx check me).
    res = widen(c_nice(inc))
    if res == -1:
        err = get_saved_errno()
        if err != 0:
            raise OSError(err, "os_nice failed")
    return res

c_ctermid = external('ctermid', [rffi.CCHARP], rffi.CCHARP)

@replace_os_function('ctermid')
def ctermid():
    return rffi.charp2str(c_ctermid(lltype.nullptr(rffi.CCHARP.TO)))

c_tmpnam = external('tmpnam', [rffi.CCHARP], rffi.CCHARP)

@replace_os_function('tmpnam')
def tmpnam():
    return rffi.charp2str(c_tmpnam(lltype.nullptr(rffi.CCHARP.TO)))

#___________________________________________________________________

c_getpid = external('getpid', [], rffi.PID_T,
                    releasegil=False, save_err=rffi.RFFI_SAVE_ERRNO)
c_getppid = external('getppid', [], rffi.PID_T,
                     releasegil=False, save_err=rffi.RFFI_SAVE_ERRNO)
c_setsid = external('setsid', [], rffi.PID_T,
                    save_err=rffi.RFFI_SAVE_ERRNO)
c_getsid = external('getsid', [rffi.PID_T], rffi.PID_T,
                    save_err=rffi.RFFI_SAVE_ERRNO)

@replace_os_function('getpid')
def getpid():
    return handle_posix_error('getpid', c_getpid())

@replace_os_function('getppid')
def getppid():
    return handle_posix_error('getppid', c_getppid())

@replace_os_function('setsid')
def setsid():
    return handle_posix_error('setsid', c_setsid())

@replace_os_function('getsid')
def getsid(pid):
    return handle_posix_error('getsid', c_getsid(pid))

c_getpgid = external('getpgid', [rffi.PID_T], rffi.PID_T,
                     save_err=rffi.RFFI_SAVE_ERRNO)
c_setpgid = external('setpgid', [rffi.PID_T, rffi.PID_T], rffi.INT,
                     save_err=rffi.RFFI_SAVE_ERRNO)

@replace_os_function('getpgid')
def getpgid(pid):
    return handle_posix_error('getpgid', c_getpgid(pid))

@replace_os_function('setpgid')
def setpgid(pid, gid):
    handle_posix_error('setpgid', c_setpgid(pid, gid))

if not _WIN32:
    GID_GROUPS_T = rffi.CArrayPtr(GID_T)
    c_getgroups = external('getgroups', [rffi.INT, GID_GROUPS_T], rffi.INT,
                           save_err=rffi.RFFI_SAVE_ERRNO)
    c_setgroups = external('setgroups', [rffi.SIZE_T, GID_GROUPS_T], rffi.INT,
                           save_err=rffi.RFFI_SAVE_ERRNO)
    c_initgroups = external('initgroups', [rffi.CCHARP, GID_T], rffi.INT,
                            save_err=rffi.RFFI_SAVE_ERRNO)

@replace_os_function('getgroups')
def getgroups():
    n = handle_posix_error('getgroups',
                           c_getgroups(0, lltype.nullptr(GID_GROUPS_T.TO)))
    groups = lltype.malloc(GID_GROUPS_T.TO, n, flavor='raw')
    try:
        n = handle_posix_error('getgroups', c_getgroups(n, groups))
        return [widen_gid(groups[i]) for i in range(n)]
    finally:
        lltype.free(groups, flavor='raw')

@replace_os_function('setgroups')
def setgroups(gids):
    n = len(gids)
    groups = lltype.malloc(GID_GROUPS_T.TO, n, flavor='raw')
    try:
        for i in range(n):
            groups[i] = rffi.cast(GID_T, gids[i])
        handle_posix_error('setgroups', c_setgroups(n, groups))
    finally:
        lltype.free(groups, flavor='raw')

@replace_os_function('initgroups')
def initgroups(user, group):
    handle_posix_error('initgroups', c_initgroups(user, group))

if GETPGRP_HAVE_ARG:
    c_getpgrp = external('getpgrp', [rffi.INT], rffi.INT,
                         save_err=rffi.RFFI_SAVE_ERRNO)
else:
    c_getpgrp = external('getpgrp', [], rffi.INT,
                         save_err=rffi.RFFI_SAVE_ERRNO)
if SETPGRP_HAVE_ARG:
    c_setpgrp = external('setpgrp', [rffi.INT, rffi.INT], rffi.INT,
                         save_err=rffi.RFFI_SAVE_ERRNO)
else:
    c_setpgrp = external('setpgrp', [], rffi.INT,
                         save_err=rffi.RFFI_SAVE_ERRNO)

@replace_os_function('getpgrp')
def getpgrp():
    if GETPGRP_HAVE_ARG:
        return handle_posix_error('getpgrp', c_getpgrp(0))
    else:
        return handle_posix_error('getpgrp', c_getpgrp())

@replace_os_function('setpgrp')
def setpgrp():
    if SETPGRP_HAVE_ARG:
        handle_posix_error('setpgrp', c_setpgrp(0, 0))
    else:
        handle_posix_error('setpgrp', c_setpgrp())

c_tcgetpgrp = external('tcgetpgrp', [rffi.INT], rffi.PID_T,
                       save_err=rffi.RFFI_SAVE_ERRNO)
c_tcsetpgrp = external('tcsetpgrp', [rffi.INT, rffi.PID_T], rffi.INT,
                       save_err=rffi.RFFI_SAVE_ERRNO)

@replace_os_function('tcgetpgrp')
def tcgetpgrp(fd):
    return handle_posix_error('tcgetpgrp', c_tcgetpgrp(fd))

@replace_os_function('tcsetpgrp')
def tcsetpgrp(fd, pgrp):
    return handle_posix_error('tcsetpgrp', c_tcsetpgrp(fd, pgrp))

#___________________________________________________________________

if not _WIN32:
    c_getuid = external('getuid', [], UID_T)
    c_geteuid = external('geteuid', [], UID_T)
    c_setuid = external('setuid', [UID_T], rffi.INT,
                        save_err=rffi.RFFI_SAVE_ERRNO)
    c_seteuid = external('seteuid', [UID_T], rffi.INT,
                         save_err=rffi.RFFI_SAVE_ERRNO)
    c_getgid = external('getgid', [], GID_T)
    c_getegid = external('getegid', [], GID_T)
    c_setgid = external('setgid', [GID_T], rffi.INT,
                        save_err=rffi.RFFI_SAVE_ERRNO)
    c_setegid = external('setegid', [GID_T], rffi.INT,
                         save_err=rffi.RFFI_SAVE_ERRNO)

    def widen_uid(x):
        return rffi.cast(lltype.Unsigned, x)
    widen_gid = widen_uid

    # NOTE: the resulting type of functions that return a uid/gid is
    # always Unsigned.  The argument type of functions that take a
    # uid/gid should also be Unsigned.

    @replace_os_function('getuid')
    def getuid():
        return widen_uid(c_getuid())

    @replace_os_function('geteuid')
    def geteuid():
        return widen_uid(c_geteuid())

    @replace_os_function('setuid')
    def setuid(uid):
        handle_posix_error('setuid', c_setuid(uid))

    @replace_os_function('seteuid')
    def seteuid(uid):
        handle_posix_error('seteuid', c_seteuid(uid))

    @replace_os_function('getgid')
    def getgid():
        return widen_gid(c_getgid())

    @replace_os_function('getegid')
    def getegid():
        return widen_gid(c_getegid())

    @replace_os_function('setgid')
    def setgid(gid):
        handle_posix_error('setgid', c_setgid(gid))

    @replace_os_function('setegid')
    def setegid(gid):
        handle_posix_error('setegid', c_setegid(gid))

    c_setreuid = external('setreuid', [UID_T, UID_T], rffi.INT,
                          save_err=rffi.RFFI_SAVE_ERRNO)
    c_setregid = external('setregid', [GID_T, GID_T], rffi.INT,
                          save_err=rffi.RFFI_SAVE_ERRNO)

    @replace_os_function('setreuid')
    def setreuid(ruid, euid):
        handle_posix_error('setreuid', c_setreuid(ruid, euid))

    @replace_os_function('setregid')
    def setregid(rgid, egid):
        handle_posix_error('setregid', c_setregid(rgid, egid))

    UID_T_P = lltype.Ptr(lltype.Array(UID_T, hints={'nolength': True}))
    GID_T_P = lltype.Ptr(lltype.Array(GID_T, hints={'nolength': True}))
    c_getresuid = external('getresuid', [UID_T_P] * 3, rffi.INT,
                           save_err=rffi.RFFI_SAVE_ERRNO)
    c_getresgid = external('getresgid', [GID_T_P] * 3, rffi.INT,
                           save_err=rffi.RFFI_SAVE_ERRNO)
    c_setresuid = external('setresuid', [UID_T] * 3, rffi.INT,
                           save_err=rffi.RFFI_SAVE_ERRNO)
    c_setresgid = external('setresgid', [GID_T] * 3, rffi.INT,
                           save_err=rffi.RFFI_SAVE_ERRNO)

    @replace_os_function('getresuid')
    def getresuid():
        out = lltype.malloc(UID_T_P.TO, 3, flavor='raw')
        try:
            handle_posix_error('getresuid',
                               c_getresuid(rffi.ptradd(out, 0),
                                           rffi.ptradd(out, 1),
                                           rffi.ptradd(out, 2)))
            return (widen_uid(out[0]), widen_uid(out[1]), widen_uid(out[2]))
        finally:
            lltype.free(out, flavor='raw')

    @replace_os_function('getresgid')
    def getresgid():
        out = lltype.malloc(GID_T_P.TO, 3, flavor='raw')
        try:
            handle_posix_error('getresgid',
                               c_getresgid(rffi.ptradd(out, 0),
                                           rffi.ptradd(out, 1),
                                           rffi.ptradd(out, 2)))
            return (widen_gid(out[0]), widen_gid(out[1]), widen_gid(out[2]))
        finally:
            lltype.free(out, flavor='raw')

    @replace_os_function('setresuid')
    def setresuid(ruid, euid, suid):
        handle_posix_error('setresuid', c_setresuid(ruid, euid, suid))

    @replace_os_function('setresgid')
    def setresgid(rgid, egid, sgid):
        handle_posix_error('setresgid', c_setresgid(rgid, egid, sgid))

#___________________________________________________________________

c_chroot = external('chroot', [rffi.CCHARP], rffi.INT,
                    save_err=rffi.RFFI_SAVE_ERRNO,
                    macro=_MACRO_ON_POSIX)

@replace_os_function('chroot')
def chroot(path):
    handle_posix_error('chroot', c_chroot(_as_bytes0(path)))

if not _WIN32:
    CHARARRAY1 = lltype.FixedSizeArray(lltype.Char, 1)
    class CConfig:
        _compilation_info_ = ExternalCompilationInfo(
            includes = ['sys/utsname.h']
        )
        UTSNAME = rffi_platform.Struct('struct utsname', [
            ('sysname',  CHARARRAY1),
            ('nodename', CHARARRAY1),
            ('release',  CHARARRAY1),
            ('version',  CHARARRAY1),
            ('machine',  CHARARRAY1)])
    config = rffi_platform.configure(CConfig)
    UTSNAMEP = lltype.Ptr(config['UTSNAME'])

    c_uname = external('uname', [UTSNAMEP], rffi.INT,
                       compilation_info=CConfig._compilation_info_,
                       save_err=rffi.RFFI_SAVE_ERRNO)

@replace_os_function('uname')
def uname():
    l_utsbuf = lltype.malloc(UTSNAMEP.TO, flavor='raw')
    try:
        handle_posix_error('uname', c_uname(l_utsbuf))
        return (
            rffi.charp2str(rffi.cast(rffi.CCHARP, l_utsbuf.c_sysname)),
            rffi.charp2str(rffi.cast(rffi.CCHARP, l_utsbuf.c_nodename)),
            rffi.charp2str(rffi.cast(rffi.CCHARP, l_utsbuf.c_release)),
            rffi.charp2str(rffi.cast(rffi.CCHARP, l_utsbuf.c_version)),
            rffi.charp2str(rffi.cast(rffi.CCHARP, l_utsbuf.c_machine)),
        )
    finally:
        lltype.free(l_utsbuf, flavor='raw')

# These are actually macros on some/most systems
c_makedev = external('makedev', [rffi.INT, rffi.INT], rffi.INT)
c_major = external('major', [rffi.INT], rffi.INT)
c_minor = external('minor', [rffi.INT], rffi.INT)

@replace_os_function('makedev')
@jit.dont_look_inside
def makedev(maj, min):
    return c_makedev(maj, min)

@replace_os_function('major')
@jit.dont_look_inside
def major(dev):
    return c_major(dev)

@replace_os_function('minor')
@jit.dont_look_inside
def minor(dev):
    return c_minor(dev)

#___________________________________________________________________

c_sysconf = external('sysconf', [rffi.INT], rffi.LONG,
                     save_err=rffi.RFFI_FULL_ERRNO_ZERO)
c_fpathconf = external('fpathconf', [rffi.INT, rffi.INT], rffi.LONG,
                       save_err=rffi.RFFI_FULL_ERRNO_ZERO)
c_pathconf = external('pathconf', [rffi.CCHARP, rffi.INT], rffi.LONG,
                      save_err=rffi.RFFI_FULL_ERRNO_ZERO)
c_confstr = external('confstr',
                     [rffi.INT, rffi.CCHARP, rffi.SIZE_T], rffi.SIZE_T,
                      save_err=rffi.RFFI_FULL_ERRNO_ZERO)

@replace_os_function('sysconf')
def sysconf(value):
    res = c_sysconf(value)
    if res == -1:
        errno = get_saved_errno()
        if errno != 0:
            raise OSError(errno, "sysconf failed")
    return res

@replace_os_function('fpathconf')
def fpathconf(fd, value):
    res = c_fpathconf(fd, value)
    if res == -1:
        errno = get_saved_errno()
        if errno != 0:
            raise OSError(errno, "fpathconf failed")
    return res

@replace_os_function('pathconf')
def pathconf(path, value):
    res = c_pathconf(_as_bytes0(path), value)
    if res == -1:
        errno = get_saved_errno()
        if errno != 0:
            raise OSError(errno, "pathconf failed")
    return res

@replace_os_function('confstr')
def confstr(value):
    n = intmask(c_confstr(value, lltype.nullptr(rffi.CCHARP.TO), 0))
    if n > 0:
        buf = lltype.malloc(rffi.CCHARP.TO, n, flavor='raw')
        try:
            c_confstr(value, buf, n)
            return rffi.charp2strn(buf, n)
        finally:
            lltype.free(buf, flavor='raw')
    else:
        errno = get_saved_errno()
        if errno != 0:
            raise OSError(errno, "confstr failed")
        return None

# ____________________________________________________________
# Support for os.environ

# XXX only for systems where os.environ is an instance of _Environ,
# which should cover Unix and Windows at least
assert type(os.environ) is not dict

from rpython.rtyper.controllerentry import ControllerEntryForPrebuilt

class EnvironExtRegistry(ControllerEntryForPrebuilt):
    _about_ = os.environ

    def getcontroller(self):
        from rpython.rlib.rposix_environ import OsEnvironController
        return OsEnvironController()


# ____________________________________________________________
# Support for f... and ...at families of POSIX functions

class CConfig:
    _compilation_info_ = ExternalCompilationInfo(
        includes=['sys/stat.h',
                  'sys/time.h',
                  'unistd.h',
                  'fcntl.h'],
    )
    for _name in """faccessat fchdir fchmod fchmodat fchown fchownat fexecve
            fdopendir fpathconf fstat fstatat fstatvfs ftruncate
            futimens futimes futimesat linkat chflags lchflags lchmod lchown
            lstat lutimes mkdirat mkfifoat mknodat openat readlinkat renameat
            symlinkat unlinkat utimensat""".split():
        locals()['HAVE_%s' % _name.upper()] = rffi_platform.Has(_name)
cConfig = rffi_platform.configure(CConfig)
globals().update(cConfig)

if not _WIN32:
    class CConfig:
        _compilation_info_ = ExternalCompilationInfo(
            includes=['sys/stat.h',
                    'unistd.h',
                    'fcntl.h'],
        )
        AT_FDCWD = rffi_platform.DefinedConstantInteger('AT_FDCWD')
        AT_SYMLINK_NOFOLLOW = rffi_platform.DefinedConstantInteger('AT_SYMLINK_NOFOLLOW')
        AT_EACCESS = rffi_platform.DefinedConstantInteger('AT_EACCESS')
        AT_REMOVEDIR = rffi_platform.DefinedConstantInteger('AT_REMOVEDIR')
        AT_EMPTY_PATH = rffi_platform.DefinedConstantInteger('AT_EMPTY_PATH')
        UTIME_NOW = rffi_platform.DefinedConstantInteger('UTIME_NOW')
        UTIME_OMIT = rffi_platform.DefinedConstantInteger('UTIME_OMIT')
        TIMESPEC = rffi_platform.Struct('struct timespec', [
            ('tv_sec', rffi.TIME_T),
            ('tv_nsec', rffi.LONG)])

    cConfig = rffi_platform.configure(CConfig)
    globals().update(cConfig)
    TIMESPEC2P = rffi.CArrayPtr(TIMESPEC)

if HAVE_FACCESSAT:
    c_faccessat = external('faccessat',
        [rffi.INT, rffi.CCHARP, rffi.INT, rffi.INT], rffi.INT)

    def faccessat(pathname, mode, dir_fd=AT_FDCWD,
            effective_ids=False, follow_symlinks=True):
        """Thin wrapper around faccessat(2) with an interface simlar to
        Python3's os.access().
        """
        flags = 0
        if not follow_symlinks:
            flags |= AT_SYMLINK_NOFOLLOW
        if effective_ids:
            flags |= AT_EACCESS
        error = c_faccessat(dir_fd, pathname, mode, flags)
        return error == 0

if HAVE_FCHMODAT:
    c_fchmodat = external('fchmodat',
        [rffi.INT, rffi.CCHARP, rffi.INT, rffi.INT], rffi.INT,
        save_err=rffi.RFFI_SAVE_ERRNO,)

    def fchmodat(path, mode, dir_fd=AT_FDCWD, follow_symlinks=True):
        if follow_symlinks:
            flag = 0
        else:
            flag = AT_SYMLINK_NOFOLLOW
        error = c_fchmodat(dir_fd, path, mode, flag)
        handle_posix_error('fchmodat', error)

if HAVE_FCHOWNAT:
    c_fchownat = external('fchownat',
        [rffi.INT, rffi.CCHARP, rffi.INT, rffi.INT, rffi.INT], rffi.INT,
        save_err=rffi.RFFI_SAVE_ERRNO,)

    def fchownat(path, owner, group, dir_fd=AT_FDCWD,
            follow_symlinks=True, empty_path=False):
        flag = 0
        if not follow_symlinks:
            flag |= AT_SYMLINK_NOFOLLOW
        if empty_path:
            flag |= AT_EMPTY_PATH
        error = c_fchownat(dir_fd, path, owner, group, flag)
        handle_posix_error('fchownat', error)

if HAVE_FEXECVE:
    c_fexecve = external('fexecve',
        [rffi.INT, rffi.CCHARPP, rffi.CCHARPP], rffi.INT,
        save_err=rffi.RFFI_SAVE_ERRNO)

    def fexecve(fd, args, env):
        envstrs = []
        for item in env.iteritems():
            envstr = "%s=%s" % item
            envstrs.append(envstr)

        # This list conversion already takes care of NUL bytes.
        l_args = rffi.ll_liststr2charpp(args)
        l_env = rffi.ll_liststr2charpp(envstrs)
        c_fexecve(fd, l_args, l_env)

        rffi.free_charpp(l_env)
        rffi.free_charpp(l_args)
        raise OSError(get_saved_errno(), "execve failed")

if HAVE_LINKAT:
    c_linkat = external('linkat',
        [rffi.INT, rffi.CCHARP, rffi.INT, rffi.CCHARP, rffi.INT], rffi.INT)

    def linkat(src, dst, src_dir_fd=AT_FDCWD, dst_dir_fd=AT_FDCWD,
            follow_symlinks=True):
        """Thin wrapper around linkat(2) with an interface similar to
        Python3's os.link()
        """
        if follow_symlinks:
            flag = 0
        else:
            flag = AT_SYMLINK_NOFOLLOW
        error = c_linkat(src_dir_fd, src, dst_dir_fd, dst, flag)
        handle_posix_error('linkat', error)

if HAVE_FUTIMENS:
    c_futimens = external('futimens', [rffi.INT, TIMESPEC2P], rffi.INT)

    def futimens(fd, atime, atime_ns, mtime, mtime_ns):
        l_times = lltype.malloc(TIMESPEC2P.TO, 2, flavor='raw')
        rffi.setintfield(l_times[0], 'c_tv_sec', atime)
        rffi.setintfield(l_times[0], 'c_tv_nsec', atime_ns)
        rffi.setintfield(l_times[1], 'c_tv_sec', mtime)
        rffi.setintfield(l_times[1], 'c_tv_nsec', mtime_ns)
        error = c_futimens(fd, l_times)
        lltype.free(l_times, flavor='raw')
        handle_posix_error('futimens', error)

if HAVE_UTIMENSAT:
    c_utimensat = external('utimensat',
        [rffi.INT, rffi.CCHARP, TIMESPEC2P, rffi.INT], rffi.INT)

    def utimensat(pathname, atime, atime_ns, mtime, mtime_ns,
            dir_fd=AT_FDCWD, follow_symlinks=True):
        """Wrapper around utimensat(2)

        To set access time to the current time, pass atime_ns=UTIME_NOW,
        atime is then ignored.

        To set modification time to the current time, pass mtime_ns=UTIME_NOW,
        mtime is then ignored.
        """
        l_times = lltype.malloc(TIMESPEC2P.TO, 2, flavor='raw')
        rffi.setintfield(l_times[0], 'c_tv_sec', atime)
        rffi.setintfield(l_times[0], 'c_tv_nsec', atime_ns)
        rffi.setintfield(l_times[1], 'c_tv_sec', mtime)
        rffi.setintfield(l_times[1], 'c_tv_nsec', mtime_ns)
        if follow_symlinks:
            flag = 0
        else:
            flag = AT_SYMLINK_NOFOLLOW
        error = c_utimensat(dir_fd, pathname, l_times, flag)
        lltype.free(l_times, flavor='raw')
        handle_posix_error('utimensat', error)

if HAVE_LUTIMES:
    c_lutimes = external('lutimes',
        [rffi.CCHARP, TIMEVAL2P], rffi.INT,
        save_err=rffi.RFFI_SAVE_ERRNO)

    @specialize.argtype(1)
    def lutimes(pathname, times):
        if times is None:
            error = c_lutimes(pathname, lltype.nullptr(TIMEVAL2P.TO))
        else:
            with lltype.scoped_alloc(TIMEVAL2P.TO, 2) as l_timeval2p:
                times_to_timeval2p(times, l_timeval2p)
                error = c_lutimes(pathname, l_timeval2p)
        handle_posix_error('lutimes', error)

if HAVE_FUTIMES:
    c_futimes = external('futimes',
        [rffi.INT, TIMEVAL2P], rffi.INT,
        save_err=rffi.RFFI_SAVE_ERRNO)

    @specialize.argtype(1)
    def futimes(fd, times):
        if times is None:
            error = c_futimes(fd, lltype.nullptr(TIMEVAL2P.TO))
        else:
            with lltype.scoped_alloc(TIMEVAL2P.TO, 2) as l_timeval2p:
                times_to_timeval2p(times, l_timeval2p)
                error = c_futimes(fd, l_timeval2p)
        handle_posix_error('futimes', error)

if HAVE_MKDIRAT:
    c_mkdirat = external('mkdirat',
        [rffi.INT, rffi.CCHARP, rffi.INT], rffi.INT,
        save_err=rffi.RFFI_SAVE_ERRNO)

    def mkdirat(pathname, mode, dir_fd=AT_FDCWD):
        error = c_mkdirat(dir_fd, pathname, mode)
        handle_posix_error('mkdirat', error)

if HAVE_UNLINKAT:
    c_unlinkat = external('unlinkat',
        [rffi.INT, rffi.CCHARP, rffi.INT], rffi.INT,
        save_err=rffi.RFFI_SAVE_ERRNO)

    def unlinkat(pathname, dir_fd=AT_FDCWD, removedir=False):
        flag = AT_REMOVEDIR if removedir else 0
        error = c_unlinkat(dir_fd, pathname, flag)
        handle_posix_error('unlinkat', error)

if HAVE_READLINKAT:
    c_readlinkat = external(
        'readlinkat',
        [rffi.INT, rffi.CCHARP, rffi.CCHARP, rffi.SIZE_T], rffi.SSIZE_T,
        save_err=rffi.RFFI_SAVE_ERRNO)

    def readlinkat(pathname, dir_fd=AT_FDCWD):
        pathname = _as_bytes0(pathname)
        bufsize = 1023
        while True:
            buf = lltype.malloc(rffi.CCHARP.TO, bufsize, flavor='raw')
            res = widen(c_readlinkat(dir_fd, pathname, buf, bufsize))
            if res < 0:
                lltype.free(buf, flavor='raw')
                error = get_saved_errno()    # failed
                raise OSError(error, "readlinkat failed")
            elif res < bufsize:
                break                       # ok
            else:
                # buf too small, try again with a larger buffer
                lltype.free(buf, flavor='raw')
                bufsize *= 4
        # convert the result to a string
        result = rffi.charp2strn(buf, res)
        lltype.free(buf, flavor='raw')
        return result

if HAVE_RENAMEAT:
    c_renameat = external(
        'renameat',
        [rffi.INT, rffi.CCHARP, rffi.INT, rffi.CCHARP], rffi.INT,
        save_err=rffi.RFFI_SAVE_ERRNO)

    def renameat(src, dst, src_dir_fd=AT_FDCWD, dst_dir_fd=AT_FDCWD):
        error = c_renameat(src_dir_fd, src, dst_dir_fd, dst)
        handle_posix_error('renameat', error)


if HAVE_SYMLINKAT:
    c_symlinkat = external('symlinkat',
        [rffi.CCHARP, rffi.INT, rffi.CCHARP], rffi.INT,
        save_err=rffi.RFFI_SAVE_ERRNO)

    def symlinkat(src, dst, dir_fd=AT_FDCWD):
        error = c_symlinkat(src, dir_fd, dst)
        handle_posix_error('symlinkat', error)

if HAVE_OPENAT:
    c_openat = external('openat',
        [rffi.INT, rffi.CCHARP, rffi.INT, rffi.MODE_T], rffi.INT,
        save_err=rffi.RFFI_SAVE_ERRNO)

    @enforceargs(s_Str0, int, int, int, typecheck=False)
    def openat(path, flags, mode, dir_fd=AT_FDCWD):
        fd = c_openat(dir_fd, path, flags, mode)
        return handle_posix_error('open', fd)

if HAVE_MKFIFOAT:
    c_mkfifoat = external('mkfifoat',
        [rffi.INT, rffi.CCHARP, rffi.MODE_T], rffi.INT,
        save_err=rffi.RFFI_SAVE_ERRNO)

    def mkfifoat(path, mode, dir_fd=AT_FDCWD):
        error = c_mkfifoat(dir_fd, path, mode)
        handle_posix_error('mkfifoat', error)

if HAVE_MKNODAT:
    c_mknodat = external('mknodat',
        [rffi.INT, rffi.CCHARP, rffi.MODE_T, rffi.INT], rffi.INT,
        save_err=rffi.RFFI_SAVE_ERRNO)

    def mknodat(path, mode, device, dir_fd=AT_FDCWD):
        error = c_mknodat(dir_fd, path, mode, device)
        handle_posix_error('mknodat', error)


eci_inheritable = eci.merge(ExternalCompilationInfo(
    separate_module_sources=["""
RPY_EXTERN
int rpy_set_inheritable(int fd, int inheritable)
{
    /* XXX minimal impl. XXX */
    int request = inheritable ? FIONCLEX : FIOCLEX;
    return ioctl(fd, request, NULL);
}
RPY_EXTERN
int rpy_get_inheritable(int fd)
{
    int flags = fcntl(fd, F_GETFD, 0);
    if (flags == -1)
        return -1;
    return !(flags & FD_CLOEXEC);
}
    """],
    post_include_bits=['RPY_EXTERN int rpy_set_inheritable(int, int);']))

c_set_inheritable = external('rpy_set_inheritable', [rffi.INT, rffi.INT],
                             rffi.INT, save_err=rffi.RFFI_SAVE_ERRNO,
                             compilation_info=eci_inheritable)
c_get_inheritable = external('rpy_get_inheritable', [rffi.INT],
                             rffi.INT, save_err=rffi.RFFI_SAVE_ERRNO,
                             compilation_info=eci_inheritable)

def set_inheritable(fd, inheritable):
    error = c_set_inheritable(fd, inheritable)
    handle_posix_error('set_inheritable', error)

def get_inheritable(fd):
    res = c_get_inheritable(fd)
    res = handle_posix_error('get_inheritable', res)
    return res != 0