On Tue, 16 Nov 2021 12:18:47 +0900 Takashi Yano wrote: > - NtReadFile() and NtWriteFile() seems to return STATUS_PENDING > occasionally even in nonblocking mode. This patch adds handling > for STATUS_PENDING in nonblocking mode. > > Addresses: > https://cygwin.com/pipermail/cygwin/2021-November/249910.html > --- > winsup/cygwin/fhandler_pipe.cc | 10 ++++++---- > winsup/cygwin/release/3.3.3 | 5 +++++ > 2 files changed, 11 insertions(+), 4 deletions(-) > > diff --git a/winsup/cygwin/fhandler_pipe.cc b/winsup/cygwin/fhandler_pipe.cc > index 1ebf4de10..f70ff56fe 100644 > --- a/winsup/cygwin/fhandler_pipe.cc > +++ b/winsup/cygwin/fhandler_pipe.cc > @@ -336,9 +336,10 @@ fhandler_pipe::raw_read (void *ptr, size_t& len) > break; > status = NtReadFile (get_handle (), evt, NULL, NULL, &io, ptr, > len1, NULL, NULL); > - if (evt && status == STATUS_PENDING) > + if (status == STATUS_PENDING) > { > - waitret = cygwait (evt, INFINITE, cw_cancel | cw_sig); > + HANDLE w = evt ?: get_handle (); > + waitret = cygwait (w, INFINITE, cw_cancel | cw_sig); > /* If io.Status is STATUS_CANCELLED after CancelIo, IO has actually > been cancelled and io.Information contains the number of bytes > processed so far. > @@ -507,10 +508,11 @@ fhandler_pipe_fifo::raw_write (const void *ptr, size_t > len) > break; > len1 >>= 1; > } > - if (evt && status == STATUS_PENDING) > + if (status == STATUS_PENDING) > { > + HANDLE w = evt ?: get_handle (); > while (WAIT_TIMEOUT == > - (waitret = cygwait (evt, (DWORD) 0, cw_cancel | cw_sig))) > + (waitret = cygwait (w, (DWORD) 0, cw_cancel | cw_sig))) > { > if (reader_closed ()) > { > diff --git a/winsup/cygwin/release/3.3.3 b/winsup/cygwin/release/3.3.3 > index 1eb25e2fc..49c1bcdc3 100644 > --- a/winsup/cygwin/release/3.3.3 > +++ b/winsup/cygwin/release/3.3.3 > @@ -16,3 +16,8 @@ Bug Fixes > - Fix long-standing problem that new files don't get created with the > FILE_ATTRIBUTE_ARCHIVE DOS attribute set. > Addresses: https://cygwin.com/pipermail/cygwin/2021-November/249909.html > + > +- Fix issue that pipe read()/write() occationally returns a garnage > + length when NtReadFile/NtWriteFile returns STATUS_PENDING in non- > + blocking mode. > + Addresses: https://cygwin.com/pipermail/cygwin/2021-November/249910.html > -- > 2.33.0
I noticed that this patch sometimes does not work as expected. cygwaint(get_handle(), ...) may sometimes return WAIT_OBJECT_0 even when the operation is not completed. I will submit a patch according to Corinna's way. (Use event even in nonblocking mode.) -- Takashi Yano <takashi.y...@nifty.ne.jp>
