Projet_SETI_RISC-V/riscv-gnu-toolchain/gcc/libgo/go/runtime/netpoll_kqueue.go
2023-03-06 14:48:14 +01:00

195 lines
4.8 KiB
Go

// Copyright 2013 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
//go:build darwin || dragonfly || freebsd || netbsd || openbsd
package runtime
// Integrated network poller (kqueue-based implementation).
import (
"runtime/internal/atomic"
"unsafe"
)
//extern-sysinfo kqueue
func kqueue() int32
//go:noescape
//extern-sysinfo kevent
func kevent(kq int32, ch *keventt, nch uintptr, ev *keventt, nev uintptr, ts *timespec) int32
var (
kq int32 = -1
netpollBreakRd, netpollBreakWr uintptr // for netpollBreak
netpollWakeSig uint32 // used to avoid duplicate calls of netpollBreak
)
func netpollinit() {
kq = kqueue()
if kq < 0 {
println("netpollinit: kqueue failed with", errno())
throw("runtime: netpollinit failed")
}
closeonexec(kq)
r, w, errno := nonblockingPipe()
if errno != 0 {
println("runtime: pipe failed with", -errno)
throw("runtime: pipe failed")
}
ev := keventt{
filter: _EVFILT_READ,
flags: _EV_ADD,
}
*(*uintptr)(unsafe.Pointer(&ev.ident)) = uintptr(r)
n := kevent(kq, &ev, 1, nil, 0, nil)
if n < 0 {
println("runtime: kevent failed with", -n)
throw("runtime: kevent failed")
}
netpollBreakRd = uintptr(r)
netpollBreakWr = uintptr(w)
}
func netpollIsPollDescriptor(fd uintptr) bool {
return fd == uintptr(kq) || fd == netpollBreakRd || fd == netpollBreakWr
}
func netpollopen(fd uintptr, pd *pollDesc) int32 {
// Arm both EVFILT_READ and EVFILT_WRITE in edge-triggered mode (EV_CLEAR)
// for the whole fd lifetime. The notifications are automatically unregistered
// when fd is closed.
var ev [2]keventt
*(*uintptr)(unsafe.Pointer(&ev[0].ident)) = fd
ev[0].filter = _EVFILT_READ
ev[0].flags = _EV_ADD | _EV_CLEAR
ev[0].fflags = 0
ev[0].data = 0
ev[0].udata = (*byte)(unsafe.Pointer(pd))
ev[1] = ev[0]
ev[1].filter = _EVFILT_WRITE
n := kevent(kq, &ev[0], 2, nil, 0, nil)
if n < 0 {
return int32(errno())
}
return 0
}
func netpollclose(fd uintptr) int32 {
// Don't need to unregister because calling close()
// on fd will remove any kevents that reference the descriptor.
return 0
}
func netpollarm(pd *pollDesc, mode int) {
throw("runtime: unused")
}
// netpollBreak interrupts a kevent.
func netpollBreak() {
if atomic.Cas(&netpollWakeSig, 0, 1) {
for {
var b byte
n := write(netpollBreakWr, unsafe.Pointer(&b), 1)
if n == 1 || n == -_EAGAIN {
break
}
if n == -_EINTR {
continue
}
println("runtime: netpollBreak write failed with", -n)
throw("runtime: netpollBreak write failed")
}
}
}
// netpoll checks for ready network connections.
// Returns list of goroutines that become runnable.
// delay < 0: blocks indefinitely
// delay == 0: does not block, just polls
// delay > 0: block for up to that many nanoseconds
func netpoll(delay int64) gList {
if kq == -1 {
return gList{}
}
var tp *timespec
var ts timespec
if delay < 0 {
tp = nil
} else if delay == 0 {
tp = &ts
} else {
ts.setNsec(delay)
if ts.tv_sec > 1e6 {
// Darwin returns EINVAL if the sleep time is too long.
ts.tv_sec = 1e6
}
tp = &ts
}
var events [64]keventt
retry:
n := kevent(kq, nil, 0, &events[0], uintptr(len(events)), tp)
if n < 0 {
e := errno()
if e != _EINTR {
println("runtime: kevent on fd", kq, "failed with", e)
throw("runtime: netpoll failed")
}
// If a timed sleep was interrupted, just return to
// recalculate how long we should sleep now.
if delay > 0 {
return gList{}
}
goto retry
}
var toRun gList
for i := 0; i < int(n); i++ {
ev := &events[i]
if uintptr(ev.ident) == netpollBreakRd {
if ev.filter != _EVFILT_READ {
println("runtime: netpoll: break fd ready for", ev.filter)
throw("runtime: netpoll: break fd ready for something unexpected")
}
if delay != 0 {
// netpollBreak could be picked up by a
// nonblocking poll. Only read the byte
// if blocking.
var tmp [16]byte
read(int32(netpollBreakRd), noescape(unsafe.Pointer(&tmp[0])), int32(len(tmp)))
atomic.Store(&netpollWakeSig, 0)
}
continue
}
var mode int32
switch ev.filter {
case _EVFILT_READ:
mode += 'r'
// On some systems when the read end of a pipe
// is closed the write end will not get a
// _EVFILT_WRITE event, but will get a
// _EVFILT_READ event with EV_EOF set.
// Note that setting 'w' here just means that we
// will wake up a goroutine waiting to write;
// that goroutine will try the write again,
// and the appropriate thing will happen based
// on what that write returns (success, EPIPE, EAGAIN).
if ev.flags&_EV_EOF != 0 {
mode += 'w'
}
case _EVFILT_WRITE:
mode += 'w'
}
if mode != 0 {
pd := (*pollDesc)(unsafe.Pointer(ev.udata))
pd.setEventErr(ev.flags == _EV_ERROR)
netpollready(&toRun, pd, mode)
}
}
return toRun
}