mirror of
https://github.com/golang/go
synced 2024-11-20 02:14:46 -07:00
0b8d583320
os/signal depends on a few unexported runtime functions. This removes the assembly stubs it used to get access to these in favour of using //go:linkname in runtime to make the functions accessible to os/signal. This is motivated by ppc64le shared libraries, where you cannot BR to a symbol defined in a shared library (only BL), but it seems like an improvment anyway. Change-Id: I09361203ce38070bd3f132f6dc5ac212f2dc6f58 Reviewed-on: https://go-review.googlesource.com/15871 Run-TryBot: Michael Hudson-Doyle <michael.hudson@canonical.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Minux Ma <minux@golang.org> Reviewed-by: Dave Cheney <dave@cheney.net>
135 lines
2.6 KiB
Go
135 lines
2.6 KiB
Go
// Copyright 2009 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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// This file implements runtime support for signal handling.
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package runtime
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import _ "unsafe"
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const qsize = 64
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var sig struct {
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q noteQueue
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inuse bool
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lock mutex
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note note
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sleeping bool
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}
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type noteData struct {
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s [_ERRMAX]byte
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n int // n bytes of s are valid
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}
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type noteQueue struct {
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lock mutex
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data [qsize]noteData
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ri int
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wi int
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full bool
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}
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// It is not allowed to allocate memory in the signal handler.
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func (q *noteQueue) push(item *byte) bool {
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lock(&q.lock)
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if q.full {
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unlock(&q.lock)
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return false
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}
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s := gostringnocopy(item)
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copy(q.data[q.wi].s[:], s)
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q.data[q.wi].n = len(s)
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q.wi++
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if q.wi == qsize {
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q.wi = 0
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}
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if q.wi == q.ri {
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q.full = true
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}
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unlock(&q.lock)
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return true
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}
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func (q *noteQueue) pop() string {
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lock(&q.lock)
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q.full = false
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if q.ri == q.wi {
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unlock(&q.lock)
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return ""
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}
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note := &q.data[q.ri]
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item := string(note.s[:note.n])
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q.ri++
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if q.ri == qsize {
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q.ri = 0
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}
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unlock(&q.lock)
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return item
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}
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// Called from sighandler to send a signal back out of the signal handling thread.
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// Reports whether the signal was sent. If not, the caller typically crashes the program.
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func sendNote(s *byte) bool {
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if !sig.inuse {
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return false
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}
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// Add signal to outgoing queue.
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if !sig.q.push(s) {
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return false
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}
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lock(&sig.lock)
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if sig.sleeping {
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sig.sleeping = false
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notewakeup(&sig.note)
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}
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unlock(&sig.lock)
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return true
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}
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// Called to receive the next queued signal.
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// Must only be called from a single goroutine at a time.
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//go:linkname signal_recv os/signal.signal_recv
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func signal_recv() string {
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for {
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note := sig.q.pop()
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if note != "" {
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return note
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}
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lock(&sig.lock)
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sig.sleeping = true
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noteclear(&sig.note)
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unlock(&sig.lock)
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notetsleepg(&sig.note, -1)
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}
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}
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// Must only be called from a single goroutine at a time.
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//go:linkname signal_enable os/signal.signal_enable
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func signal_enable(s uint32) {
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if !sig.inuse {
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// The first call to signal_enable is for us
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// to use for initialization. It does not pass
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// signal information in m.
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sig.inuse = true // enable reception of signals; cannot disable
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noteclear(&sig.note)
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return
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}
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}
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// Must only be called from a single goroutine at a time.
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//go:linkname signal_disable os/signal.signal_disable
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func signal_disable(s uint32) {
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}
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// Must only be called from a single goroutine at a time.
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//go:linkname signal_ignore os/signal.signal_ignore
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func signal_ignore(s uint32) {
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}
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