* [PATCH v3] Cygwin: pipe: Handle STATUS_PENDING even for nonblocking mode.
@ 2021-11-16 14:33 Takashi Yano
2021-11-16 20:28 ` Ken Brown
0 siblings, 1 reply; 2+ messages in thread
From: Takashi Yano @ 2021-11-16 14:33 UTC (permalink / raw)
To: cygwin-patches
- 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 | 81 ++++++++++++++++------------------
winsup/cygwin/release/3.3.3 | 5 +++
2 files changed, 43 insertions(+), 43 deletions(-)
diff --git a/winsup/cygwin/fhandler_pipe.cc b/winsup/cygwin/fhandler_pipe.cc
index 9392a28c1..3cbd434b7 100644
--- a/winsup/cygwin/fhandler_pipe.cc
+++ b/winsup/cygwin/fhandler_pipe.cc
@@ -279,13 +279,12 @@ fhandler_pipe::raw_read (void *ptr, size_t& len)
size_t nbytes = 0;
NTSTATUS status = STATUS_SUCCESS;
IO_STATUS_BLOCK io;
- HANDLE evt = NULL;
+ HANDLE evt;
if (!len)
return;
- /* Create a wait event if we're in blocking mode. */
- if (!is_nonblocking () && !(evt = CreateEvent (NULL, false, false, NULL)))
+ if (!(evt = CreateEvent (NULL, false, false, NULL)))
{
__seterrno ();
len = (size_t) -1;
@@ -321,8 +320,7 @@ fhandler_pipe::raw_read (void *ptr, size_t& len)
ULONG len1 = (ULONG) (len - nbytes);
waitret = WAIT_OBJECT_0;
- if (evt)
- ResetEvent (evt);
+ ResetEvent (evt);
FILE_PIPE_LOCAL_INFORMATION fpli;
status = NtQueryInformationFile (get_handle (), &io,
&fpli, sizeof (fpli),
@@ -336,7 +334,7 @@ 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);
/* If io.Status is STATUS_CANCELLED after CancelIo, IO has actually
@@ -406,8 +404,7 @@ fhandler_pipe::raw_read (void *ptr, size_t& len)
break;
}
ReleaseMutex (read_mtx);
- if (evt)
- CloseHandle (evt);
+ CloseHandle (evt);
if (status == STATUS_THREAD_SIGNALED && nbytes == 0)
{
set_errno (EINTR);
@@ -437,7 +434,7 @@ fhandler_pipe_fifo::raw_write (const void *ptr, size_t len)
ULONG chunk;
NTSTATUS status = STATUS_SUCCESS;
IO_STATUS_BLOCK io;
- HANDLE evt = NULL;
+ HANDLE evt;
if (!len)
return 0;
@@ -456,8 +453,7 @@ fhandler_pipe_fifo::raw_write (const void *ptr, size_t len)
else
chunk = pipe_buf_size;
- /* Create a wait event if the pipe or fifo is in blocking mode. */
- if (!is_nonblocking () && !(evt = CreateEvent (NULL, false, false, NULL)))
+ if (!(evt = CreateEvent (NULL, false, false, NULL)))
{
__seterrno ();
return -1;
@@ -502,41 +498,41 @@ fhandler_pipe_fifo::raw_write (const void *ptr, size_t len)
{
status = NtWriteFile (get_handle (), evt, NULL, NULL, &io,
(PVOID) ptr, len1, NULL, NULL);
- if (evt || !NT_SUCCESS (status) || io.Information > 0
- || len <= PIPE_BUF)
- break;
- len1 >>= 1;
- }
- if (evt && status == STATUS_PENDING)
- {
- while (WAIT_TIMEOUT ==
- (waitret = cygwait (evt, (DWORD) 0, cw_cancel | cw_sig)))
+ if (status == STATUS_PENDING)
{
- if (reader_closed ())
+ while (WAIT_TIMEOUT ==
+ (waitret = cygwait (evt, (DWORD) 0, cw_cancel | cw_sig)))
{
- CancelIo (get_handle ());
- set_errno (EPIPE);
- raise (SIGPIPE);
- goto out;
+ if (reader_closed ())
+ {
+ CancelIo (get_handle ());
+ set_errno (EPIPE);
+ raise (SIGPIPE);
+ goto out;
+ }
+ else
+ cygwait (select_sem, 10);
}
+ /* If io.Status is STATUS_CANCELLED after CancelIo, IO has
+ actually been cancelled and io.Information contains the
+ number of bytes processed so far.
+ Otherwise IO has been finished regulary and io.Status
+ contains valid success or error information. */
+ CancelIo (get_handle ());
+ if (waitret == WAIT_SIGNALED && io.Status != STATUS_CANCELLED)
+ waitret = WAIT_OBJECT_0;
+
+ if (waitret == WAIT_CANCELED)
+ status = STATUS_THREAD_CANCELED;
+ else if (waitret == WAIT_SIGNALED)
+ status = STATUS_THREAD_SIGNALED;
else
- cygwait (select_sem, 10);
+ status = io.Status;
}
- /* If io.Status is STATUS_CANCELLED after CancelIo, IO has actually
- been cancelled and io.Information contains the number of bytes
- processed so far.
- Otherwise IO has been finished regulary and io.Status contains
- valid success or error information. */
- CancelIo (get_handle ());
- if (waitret == WAIT_SIGNALED && io.Status != STATUS_CANCELLED)
- waitret = WAIT_OBJECT_0;
-
- if (waitret == WAIT_CANCELED)
- status = STATUS_THREAD_CANCELED;
- else if (waitret == WAIT_SIGNALED)
- status = STATUS_THREAD_SIGNALED;
- else
- status = io.Status;
+ if (!is_nonblocking () || !NT_SUCCESS (status) || io.Information > 0
+ || len <= PIPE_BUF)
+ break;
+ len1 >>= 1;
}
if (isclosed ()) /* A signal handler might have closed the fd. */
{
@@ -570,8 +566,7 @@ fhandler_pipe_fifo::raw_write (const void *ptr, size_t len)
break;
}
out:
- if (evt)
- CloseHandle (evt);
+ CloseHandle (evt);
if (status == STATUS_THREAD_SIGNALED && nbytes == 0)
set_errno (EINTR);
else if (status == STATUS_THREAD_CANCELED)
diff --git a/winsup/cygwin/release/3.3.3 b/winsup/cygwin/release/3.3.3
index c1e8cefbd..615c57977 100644
--- a/winsup/cygwin/release/3.3.3
+++ b/winsup/cygwin/release/3.3.3
@@ -22,3 +22,8 @@ Bug Fixes
running bash in Windows Terminal and inserting an emoji does not
work as expected.
Addresses: https://github.com/git-for-windows/git/issues/3281
+
+- 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
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH v3] Cygwin: pipe: Handle STATUS_PENDING even for nonblocking mode.
2021-11-16 14:33 [PATCH v3] Cygwin: pipe: Handle STATUS_PENDING even for nonblocking mode Takashi Yano
@ 2021-11-16 20:28 ` Ken Brown
0 siblings, 0 replies; 2+ messages in thread
From: Ken Brown @ 2021-11-16 20:28 UTC (permalink / raw)
To: cygwin-patches
On 11/16/2021 9:33 AM, 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.
I haven't tested (I assume you have), but LGTM except for two typos below.
> +- Fix issue that pipe read()/write() occationally returns a garnage
occasionally garbage
Ken
^ permalink raw reply [flat|nested] 2+ messages in thread
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