157 lines
3.7 KiB
Go
157 lines
3.7 KiB
Go
// Copyright 2013 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package runtime
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import (
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"runtime/internal/atomic"
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"unsafe"
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)
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const _DWORD_MAX = 0xffffffff
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const _INVALID_HANDLE_VALUE = ^uintptr(0)
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// net_op must be the same as beginning of internal/poll.operation.
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// Keep these in sync.
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type net_op struct {
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// used by windows
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o overlapped
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// used by netpoll
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pd *pollDesc
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mode int32
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errno int32
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qty uint32
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}
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type overlappedEntry struct {
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key uintptr
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op *net_op // In reality it's *overlapped, but we cast it to *net_op anyway.
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internal uintptr
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qty uint32
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}
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var (
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iocphandle uintptr = _INVALID_HANDLE_VALUE // completion port io handle
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netpollWakeSig uint32 // used to avoid duplicate calls of netpollBreak
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)
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func netpollinit() {
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iocphandle = stdcall4(_CreateIoCompletionPort, _INVALID_HANDLE_VALUE, 0, 0, _DWORD_MAX)
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if iocphandle == 0 {
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println("runtime: CreateIoCompletionPort failed (errno=", getlasterror(), ")")
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throw("runtime: netpollinit failed")
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}
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}
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func netpollIsPollDescriptor(fd uintptr) bool {
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return fd == iocphandle
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}
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func netpollopen(fd uintptr, pd *pollDesc) int32 {
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if stdcall4(_CreateIoCompletionPort, fd, iocphandle, 0, 0) == 0 {
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return int32(getlasterror())
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}
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return 0
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}
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func netpollclose(fd uintptr) int32 {
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// nothing to do
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return 0
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}
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func netpollarm(pd *pollDesc, mode int) {
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throw("runtime: unused")
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}
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func netpollBreak() {
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if atomic.Cas(&netpollWakeSig, 0, 1) {
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if stdcall4(_PostQueuedCompletionStatus, iocphandle, 0, 0, 0) == 0 {
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println("runtime: netpoll: PostQueuedCompletionStatus failed (errno=", getlasterror(), ")")
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throw("runtime: netpoll: PostQueuedCompletionStatus failed")
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}
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}
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}
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// netpoll checks for ready network connections.
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// Returns list of goroutines that become runnable.
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// delay < 0: blocks indefinitely
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// delay == 0: does not block, just polls
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// delay > 0: block for up to that many nanoseconds
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func netpoll(delay int64) gList {
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var entries [64]overlappedEntry
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var wait, qty, flags, n, i uint32
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var errno int32
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var op *net_op
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var toRun gList
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mp := getg().m
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if iocphandle == _INVALID_HANDLE_VALUE {
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return gList{}
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}
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if delay < 0 {
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wait = _INFINITE
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} else if delay == 0 {
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wait = 0
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} else if delay < 1e6 {
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wait = 1
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} else if delay < 1e15 {
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wait = uint32(delay / 1e6)
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} else {
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// An arbitrary cap on how long to wait for a timer.
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// 1e9 ms == ~11.5 days.
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wait = 1e9
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}
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n = uint32(len(entries) / int(gomaxprocs))
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if n < 8 {
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n = 8
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}
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if delay != 0 {
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mp.blocked = true
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}
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if stdcall6(_GetQueuedCompletionStatusEx, iocphandle, uintptr(unsafe.Pointer(&entries[0])), uintptr(n), uintptr(unsafe.Pointer(&n)), uintptr(wait), 0) == 0 {
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mp.blocked = false
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errno = int32(getlasterror())
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if errno == _WAIT_TIMEOUT {
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return gList{}
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}
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println("runtime: GetQueuedCompletionStatusEx failed (errno=", errno, ")")
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throw("runtime: netpoll failed")
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}
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mp.blocked = false
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for i = 0; i < n; i++ {
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op = entries[i].op
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if op != nil {
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errno = 0
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qty = 0
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if stdcall5(_WSAGetOverlappedResult, op.pd.fd, uintptr(unsafe.Pointer(op)), uintptr(unsafe.Pointer(&qty)), 0, uintptr(unsafe.Pointer(&flags))) == 0 {
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errno = int32(getlasterror())
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}
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handlecompletion(&toRun, op, errno, qty)
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} else {
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atomic.Store(&netpollWakeSig, 0)
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if delay == 0 {
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// Forward the notification to the
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// blocked poller.
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netpollBreak()
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}
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}
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}
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return toRun
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}
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func handlecompletion(toRun *gList, op *net_op, errno int32, qty uint32) {
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mode := op.mode
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if mode != 'r' && mode != 'w' {
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println("runtime: GetQueuedCompletionStatusEx returned invalid mode=", mode)
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throw("runtime: netpoll failed")
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}
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op.errno = errno
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op.qty = qty
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netpollready(toRun, op.pd, mode)
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}
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