Cygwin: pipe: Stop counting reader and read all available data.
- By guarding read with read_mtx, no more than one ReadFile can be called simultaneously. So couting read handles is no longer necessary. - Make raw_read code as similar as possible to raw_write code.
This commit is contained in:
Takashi Yano
Corinna Vinschen
parent
085fc12948
commit
fadbedd9ca
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@ -221,12 +221,10 @@ fhandler_pipe::get_proc_fd_name (char *buf)
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void __reg3
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fhandler_pipe::raw_read (void *ptr, size_t& len)
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{
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NTSTATUS status;
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size_t nbytes = 0;
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NTSTATUS status = STATUS_SUCCESS;
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IO_STATUS_BLOCK io;
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HANDLE evt = NULL;
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DWORD waitret = WAIT_OBJECT_0;
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bool keep_looping = false;
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size_t orig_len = len;
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if (!len)
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return;
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@ -239,43 +237,59 @@ fhandler_pipe::raw_read (void *ptr, size_t& len)
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return;
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}
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do
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DWORD timeout = is_nonblocking () ? 0 : INFINITE;
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DWORD waitret = cygwait (read_mtx, timeout);
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switch (waitret)
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{
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len = orig_len;
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keep_looping = false;
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case WAIT_OBJECT_0:
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break;
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case WAIT_TIMEOUT:
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set_errno (EAGAIN);
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len = (size_t) -1;
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return;
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default:
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set_errno (EINTR);
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len = (size_t) -1;
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return;
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}
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while (nbytes < len)
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{
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ULONG_PTR nbytes_now = 0;
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size_t left = len - nbytes;
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ULONG len1 = (ULONG) left;
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waitret = WAIT_OBJECT_0;
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if (evt)
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ResetEvent (evt);
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if (!is_nonblocking ())
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{
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FILE_PIPE_LOCAL_INFORMATION fpli;
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ULONG reader_count;
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ULONG max_len = 64;
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WaitForSingleObject (read_mtx, INFINITE);
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/* If the pipe is empty, don't request more bytes than half the
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pipe buffer size. Every pending read lowers WriteQuotaAvailable
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on the write side and thus affects select's ability to return
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more or less reliable info whether a write succeeds or not.
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Let the size of the request depend on the number of readers
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at the time. */
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/* If the pipe is empty, don't request more bytes than pipe
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buffer size - 1. Pending read lowers WriteQuotaAvailable on
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the write side and thus affects select's ability to return
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more or less reliable info whether a write succeeds or not. */
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ULONG chunk = max_atomic_write - 1;
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status = NtQueryInformationFile (get_handle (), &io,
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&fpli, sizeof (fpli),
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FilePipeLocalInformation);
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if (NT_SUCCESS (status) && fpli.ReadDataAvailable == 0)
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if (NT_SUCCESS (status))
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{
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reader_count = get_obj_handle_count (get_handle ());
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if (reader_count < 10)
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max_len = fpli.InboundQuota / (2 * reader_count);
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if (len > max_len)
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len = max_len;
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if (fpli.ReadDataAvailable > 0)
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chunk = left;
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else if (nbytes != 0)
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break;
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else
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chunk = fpli.InboundQuota - 1;
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}
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else if (nbytes != 0)
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break;
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if (len1 > chunk)
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len1 = chunk;
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}
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status = NtReadFile (get_handle (), evt, NULL, NULL, &io, ptr,
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len, NULL, NULL);
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if (!is_nonblocking ())
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ReleaseMutex (read_mtx);
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len1, NULL, NULL);
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if (evt && status == STATUS_PENDING)
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{
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waitret = cygwait (evt);
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@ -292,13 +306,13 @@ fhandler_pipe::raw_read (void *ptr, size_t& len)
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set_errno (EBADF);
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else
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__seterrno ();
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len = (size_t) -1;
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nbytes = (size_t) -1;
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}
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else if (NT_SUCCESS (status))
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{
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len = io.Information;
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if (len == 0)
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keep_looping = true;
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nbytes_now = io.Information;
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ptr = ((char *) ptr) + nbytes_now;
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nbytes += nbytes_now;
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}
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else
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{
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@ -308,40 +322,46 @@ fhandler_pipe::raw_read (void *ptr, size_t& len)
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case STATUS_END_OF_FILE:
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case STATUS_PIPE_BROKEN:
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/* This is really EOF. */
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len = 0;
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break;
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case STATUS_MORE_ENTRIES:
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case STATUS_BUFFER_OVERFLOW:
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/* `io.Information' is supposedly valid. */
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len = io.Information;
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if (len == 0)
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keep_looping = true;
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nbytes_now = io.Information;
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ptr = ((char *) ptr) + nbytes_now;
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nbytes += nbytes_now;
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break;
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case STATUS_PIPE_LISTENING:
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case STATUS_PIPE_EMPTY:
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if (nbytes != 0)
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break;
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if (is_nonblocking ())
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{
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set_errno (EAGAIN);
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len = (size_t) -1;
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nbytes = (size_t) -1;
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break;
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}
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fallthrough;
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default:
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__seterrno_from_nt_status (status);
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len = (size_t) -1;
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nbytes = (size_t) -1;
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break;
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}
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}
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} while (keep_looping);
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if (nbytes_now == 0)
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break;
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}
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ReleaseMutex (read_mtx);
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if (evt)
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CloseHandle (evt);
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if (status == STATUS_THREAD_SIGNALED)
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if (status == STATUS_THREAD_SIGNALED && nbytes == 0)
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{
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set_errno (EINTR);
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len = (size_t) -1;
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nbytes = (size_t) -1;
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}
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else if (status == STATUS_THREAD_CANCELED)
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pthread::static_cancel_self ();
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len = nbytes;
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}
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ssize_t __reg3
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