comparison mercurial/win32.py @ 20425:ca6aa8362f33

win32: spawndetached returns pid of detached process and not of cmd.exe

win32.spawndetached starts the detached process by `cmd.exe` (or COMSPEC). The
pid it returned was the one of cmd.exe and not the one of the detached process.
When this pid is used to kill the process, the detached process is not killed,
but only cmd.exe.

With this patch the pid of the detached process is written to the pid file.
Killing the process works as expected.

The pid is only evaluated on writing the pid file. It is unnecessary to search
the pid when it is not needed. And more important, it probably does not yet
exist right after the cmd.exe process was started. When the pid is written to
the file, waiting for the start of the detached process has already happened.
Use this functionality instead of writing a 2nd wait function.

Many tests on windows will not fail anymore, all those with the first failing
line "abort: child process failed to start". (The processes still hanging
around from previous test runs have to be killed first. They still block a
tcp port.)
A good test for the functionality of this patch is test-treediscovery.t,
because it starts and kills `hg serve -d` several times.

20424:1da346bad3d8

                ('srWindow', _SMALL_RECT),
                ('dwMaximumWindowSize', _COORD)]

_STD_ERROR_HANDLE = _DWORD(-12).value

# types of parameters of C functions used (required by pypy)

_kernel32.CreateFileA.argtypes = [_LPCSTR, _DWORD, _DWORD, ctypes.c_void_p,
    _DWORD, _DWORD, _HANDLE]
_kernel32.CreateFileA.restype = _HANDLE

_user32.ShowWindow.restype = _BOOL

_WNDENUMPROC = ctypes.WINFUNCTYPE(_BOOL, _HWND, _LPARAM)
_user32.EnumWindows.argtypes = [_WNDENUMPROC, _LPARAM]
_user32.EnumWindows.restype = _BOOL

def _raiseoserror(name):
    err = ctypes.WinError()
    raise OSError(err.errno, '%s: %s' % (name, err.strerror))

                        screenbuf, ctypes.byref(csbi)):
        return width
    width = csbi.srWindow.Right - csbi.srWindow.Left
    return width

def spawndetached(args):
    # No standard library function really spawns a fully detached
    # process under win32 because they allocate pipes or other objects
    # to handle standard streams communications. Passing these objects
    # to the child process requires handle inheritance to be enabled

        None, args, None, None, False, _CREATE_NO_WINDOW,
        env, os.getcwd(), ctypes.byref(si), ctypes.byref(pi))
    if not res:
        raise ctypes.WinError

    return pi.dwProcessId

def unlink(f):
    '''try to implement POSIX' unlink semantics on Windows'''

    if os.path.isdir(f):

20425:ca6aa8362f33

                ('srWindow', _SMALL_RECT),
                ('dwMaximumWindowSize', _COORD)]

_STD_ERROR_HANDLE = _DWORD(-12).value

# CreateToolhelp32Snapshot, Process32First, Process32Next
_TH32CS_SNAPPROCESS = 0x00000002
_MAX_PATH = 260

class _tagPROCESSENTRY32(ctypes.Structure):
    _fields_ = [('dwsize', _DWORD),
                ('cntUsage', _DWORD),
                ('th32ProcessID', _DWORD),
                ('th32DefaultHeapID', ctypes.c_void_p),
                ('th32ModuleID', _DWORD),
                ('cntThreads', _DWORD),
                ('th32ParentProcessID', _DWORD),
                ('pcPriClassBase', _LONG),
                ('dwFlags', _DWORD),
                ('szExeFile', ctypes.c_char * _MAX_PATH)]

    def __init__(self):
        super(_tagPROCESSENTRY32, self).__init__()
        self.dwsize = ctypes.sizeof(self)


# types of parameters of C functions used (required by pypy)

_kernel32.CreateFileA.argtypes = [_LPCSTR, _DWORD, _DWORD, ctypes.c_void_p,
    _DWORD, _DWORD, _HANDLE]
_kernel32.CreateFileA.restype = _HANDLE

_user32.ShowWindow.restype = _BOOL

_WNDENUMPROC = ctypes.WINFUNCTYPE(_BOOL, _HWND, _LPARAM)
_user32.EnumWindows.argtypes = [_WNDENUMPROC, _LPARAM]
_user32.EnumWindows.restype = _BOOL

_kernel32.CreateToolhelp32Snapshot.argtypes = [_DWORD, _DWORD]
_kernel32.CreateToolhelp32Snapshot.restype = _BOOL

_kernel32.Process32First.argtypes = [_HANDLE, ctypes.c_void_p]
_kernel32.Process32First.restype = _BOOL

_kernel32.Process32Next.argtypes = [_HANDLE, ctypes.c_void_p]
_kernel32.Process32Next.restype = _BOOL

def _raiseoserror(name):
    err = ctypes.WinError()
    raise OSError(err.errno, '%s: %s' % (name, err.strerror))

                        screenbuf, ctypes.byref(csbi)):
        return width
    width = csbi.srWindow.Right - csbi.srWindow.Left
    return width

def _1stchild(pid):
    '''return the 1st found child of the given pid

    None is returned when no child is found'''
    pe = _tagPROCESSENTRY32()

    # create handle to list all processes
    ph = _kernel32.CreateToolhelp32Snapshot(_TH32CS_SNAPPROCESS, 0)
    if ph == _INVALID_HANDLE_VALUE:
        raise ctypes.WinError
    try:
        r = _kernel32.Process32First(ph, ctypes.byref(pe))
        # loop over all processes
        while r:
            if pe.th32ParentProcessID == pid:
                # return first child found
                return pe.th32ProcessID
            r = _kernel32.Process32Next(ph, ctypes.byref(pe))
    finally:
        _kernel32.CloseHandle(ph)
    if _kernel32.GetLastError() != _ERROR_NO_MORE_FILES:
        raise ctypes.WinError
    return None # no child found

class _tochildpid(int): # pid is _DWORD, which always matches in an int
    '''helper for spawndetached, returns the child pid on conversion to string

    Does not resolve the child pid immediately because the child may not yet be
    started.
    '''
    def childpid(self):
        '''returns the child pid of the first found child of the process
        with this pid'''
        return _1stchild(self)
    def __str__(self):
        # run when the pid is written to the file
        ppid = self.childpid()
        if ppid is None:
            # race, child has exited since check
            # fall back to this pid. Its process will also have disappeared,
            # raising the same error type later as when the child pid would
            # be returned.
            return " %d" % self
        return str(ppid)

def spawndetached(args):
    # No standard library function really spawns a fully detached
    # process under win32 because they allocate pipes or other objects
    # to handle standard streams communications. Passing these objects
    # to the child process requires handle inheritance to be enabled

        None, args, None, None, False, _CREATE_NO_WINDOW,
        env, os.getcwd(), ctypes.byref(si), ctypes.byref(pi))
    if not res:
        raise ctypes.WinError

    # _tochildpid because the process is the child of COMSPEC
    return _tochildpid(pi.dwProcessId)

def unlink(f):
    '''try to implement POSIX' unlink semantics on Windows'''

    if os.path.isdir(f):