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Cygwin: FIFO: improve termination of the listen_client thread 

Add a method fifo_client_handler::pipe_state that queries Windows for
the state of a pipe instance.  Use this to help terminate the
listen_client thread cleanly.

If the last client handler is useless, delete it instead of declaring
it invalid.
This commit is contained in:
Ken Brown 2019-06-21 18:49:11 -04:00
parent d1b36ea949
commit 5bd5e3dc6c
2 changed files with 55 additions and 15 deletions
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9
winsup/cygwin/fhandler.h
View File

@ -1244,6 +1244,11 @@ enum fifo_client_connect_state
fc_invalid
};
enum
{
FILE_PIPE_INPUT_AVAILABLE_STATE = 5
};
struct fifo_client_handler
{
fhandler_base *fh;
@ -1251,6 +1256,10 @@ struct fifo_client_handler
HANDLE connect_evt;
fifo_client_handler () : fh (NULL), state (fc_unknown), connect_evt (NULL) {}
int close ();
/* Returns FILE_PIPE_DISCONNECTED_STATE, FILE_PIPE_LISTENING_STATE,
FILE_PIPE_CONNECTED_STATE, FILE_PIPE_CLOSING_STATE,
FILE_PIPE_INPUT_AVAILABLE_STATE, or -1 on error. */
int pipe_state ();
};
class fhandler_fifo: public fhandler_base

61
winsup/cygwin/fhandler_fifo.cc
View File

@ -377,6 +377,7 @@ fhandler_fifo::listen_client_thread ()
}
}
HANDLE ph = NULL;
int ps = -1;
fifo_client_lock ();
switch (status)
{
@ -385,29 +386,38 @@ fhandler_fifo::listen_client_thread ()
record_connection (fc);
break;
case STATUS_THREAD_IS_TERMINATING:
/* Try to cancel the pending listen. Otherwise the first
writer to connect after the thread is restarted will be
invisible.
FIXME: Is there a direct way to do this? We do it by
opening and closing a write handle to the client side. */
open_pipe (ph);
/* We don't care about the return value of open_pipe. Even
if the latter failed, a writer might have connected. */
if (WaitForSingleObject (fc.connect_evt, 0) == WAIT_OBJECT_0
/* Force NtFsControlFile to complete. Otherwise the next
writer to connect might not be recorded in the client
handler list. */
status = open_pipe (ph);
if (NT_SUCCESS (status)
&& (NT_SUCCESS (io.Status) || io.Status == STATUS_PIPE_CONNECTED))
record_connection (fc);
{
debug_printf ("successfully connected bogus client");
if (delete_client_handler (nhandlers - 1) < 0)
ret = -1;
}
else if ((ps = fc.pipe_state ()) == FILE_PIPE_CONNECTED_STATE
|| ps == FILE_PIPE_INPUT_AVAILABLE_STATE)
{
/* A connection was made under our nose. */
debug_printf ("recording connection before terminating");
record_connection (fc);
}
else
fc.state = fc_invalid;
/* By closing ph we ensure that if fc connected to ph, fc
will be declared invalid on the next read attempt. */
{
debug_printf ("failed to terminate NtFsControlFile cleanly");
delete_client_handler (nhandlers - 1);
ret = -1;
}
if (ph)
CloseHandle (ph);
fifo_client_unlock ();
goto out;
default:
debug_printf ("NtFsControlFile status %y", status);
__seterrno_from_nt_status (status);
fc.state = fc_invalid;
delete_client_handler (nhandlers - 1);
fifo_client_unlock ();
goto out;
}
@ -898,6 +908,27 @@ fifo_client_handler::close ()
return res;
}
int
fifo_client_handler::pipe_state ()
{
IO_STATUS_BLOCK io;
FILE_PIPE_LOCAL_INFORMATION fpli;
NTSTATUS status;
status = NtQueryInformationFile (fh->get_handle (), &io, &fpli,
sizeof (fpli), FilePipeLocalInformation);
if (!NT_SUCCESS (status))
{
debug_printf ("NtQueryInformationFile status %y", status);
__seterrno_from_nt_status (status);
return -1;
}
else if (fpli.ReadDataAvailable > 0)
return FILE_PIPE_INPUT_AVAILABLE_STATE;
else
return fpli.NamedPipeState;
}
int
fhandler_fifo::stop_listen_client ()
{