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// Copyright 2011 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.
package runtime
import "unsafe"
type mOS struct {
waitsema uintptr // semaphore for parking on locks
}
//extern malloc
func libc_malloc(uintptr) unsafe.Pointer
//go:noescape
//extern sem_init
func sem_init(sem *semt, pshared int32, value uint32) int32
//go:noescape
//extern sem_wait
func sem_wait(sem *semt) int32
//go:noescape
//extern sem_post
func sem_post(sem *semt) int32
//go:noescape
//extern sem_reltimedwait_np
func sem_reltimedwait_np(sem *semt, timeout *timespec) int32
//go:nosplit
func semacreate(mp *m) {
if mp.mos.waitsema != 0 {
return
}
var sem *semt
// Call libc's malloc rather than malloc. This will
// allocate space on the C heap. We can't call malloc
// here because it could cause a deadlock.
sem = (*semt)(libc_malloc(unsafe.Sizeof(*sem)))
if sem_init(sem, 0, 0) != 0 {
throw("sem_init")
}
mp.mos.waitsema = uintptr(unsafe.Pointer(sem))
}
//go:nosplit
func semasleep(ns int64) int32 {
_m_ := getg().m
if ns >= 0 {
var ts timespec
ts.set_sec(ns / 1000000000)
ts.set_nsec(int32(ns % 1000000000))
if sem_reltimedwait_np((*semt)(unsafe.Pointer(_m_.mos.waitsema)), &ts) != 0 {
err := errno()
if err == _ETIMEDOUT || err == _EAGAIN || err == _EINTR {
return -1
}
throw("sem_reltimedwait_np")
}
return 0
}
for {
r1 := sem_wait((*semt)(unsafe.Pointer(_m_.mos.waitsema)))
if r1 == 0 {
break
}
if errno() == _EINTR {
continue
}
throw("sem_wait")
}
return 0
}
//go:nosplit
func semawakeup(mp *m) {
if sem_post((*semt)(unsafe.Pointer(mp.mos.waitsema))) != 0 {
throw("sem_post")
}
}
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