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Source file src/runtime/os_netbsd.go

Documentation: runtime

  // Copyright 2014 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 (
  	"runtime/internal/atomic"
  	"unsafe"
  )
  
  const (
  	_SS_DISABLE  = 4
  	_SIG_BLOCK   = 1
  	_SIG_UNBLOCK = 2
  	_SIG_SETMASK = 3
  	_NSIG        = 33
  	_SI_USER     = 0
  
  	// From NetBSD's <sys/ucontext.h>
  	_UC_SIGMASK = 0x01
  	_UC_CPU     = 0x04
  
  	_EAGAIN = 35
  )
  
  type mOS struct {
  	waitsemacount uint32
  }
  
  //go:noescape
  func setitimer(mode int32, new, old *itimerval)
  
  //go:noescape
  func sigaction(sig uint32, new, old *sigactiont)
  
  //go:noescape
  func sigaltstack(new, old *stackt)
  
  //go:noescape
  func sigprocmask(how int32, new, old *sigset)
  
  //go:noescape
  func sysctl(mib *uint32, miblen uint32, out *byte, size *uintptr, dst *byte, ndst uintptr) int32
  
  func lwp_tramp()
  
  func raise(sig uint32)
  func raiseproc(sig uint32)
  
  //go:noescape
  func getcontext(ctxt unsafe.Pointer)
  
  //go:noescape
  func lwp_create(ctxt unsafe.Pointer, flags uintptr, lwpid unsafe.Pointer) int32
  
  //go:noescape
  func lwp_park(abstime *timespec, unpark int32, hint, unparkhint unsafe.Pointer) int32
  
  //go:noescape
  func lwp_unpark(lwp int32, hint unsafe.Pointer) int32
  
  func lwp_self() int32
  
  func osyield()
  
  const (
  	_ESRCH     = 3
  	_ETIMEDOUT = 60
  
  	// From NetBSD's <sys/time.h>
  	_CLOCK_REALTIME  = 0
  	_CLOCK_VIRTUAL   = 1
  	_CLOCK_PROF      = 2
  	_CLOCK_MONOTONIC = 3
  )
  
  var sigset_all = sigset{[4]uint32{^uint32(0), ^uint32(0), ^uint32(0), ^uint32(0)}}
  
  // From NetBSD's <sys/sysctl.h>
  const (
  	_CTL_HW      = 6
  	_HW_NCPU     = 3
  	_HW_PAGESIZE = 7
  )
  
  func getncpu() int32 {
  	mib := [2]uint32{_CTL_HW, _HW_NCPU}
  	out := uint32(0)
  	nout := unsafe.Sizeof(out)
  	ret := sysctl(&mib[0], 2, (*byte)(unsafe.Pointer(&out)), &nout, nil, 0)
  	if ret >= 0 {
  		return int32(out)
  	}
  	return 1
  }
  
  func getPageSize() uintptr {
  	mib := [2]uint32{_CTL_HW, _HW_PAGESIZE}
  	out := uint32(0)
  	nout := unsafe.Sizeof(out)
  	ret := sysctl(&mib[0], 2, (*byte)(unsafe.Pointer(&out)), &nout, nil, 0)
  	if ret >= 0 {
  		return uintptr(out)
  	}
  	return 0
  }
  
  //go:nosplit
  func semacreate(mp *m) {
  }
  
  //go:nosplit
  func semasleep(ns int64) int32 {
  	_g_ := getg()
  
  	// Compute sleep deadline.
  	var tsp *timespec
  	if ns >= 0 {
  		var ts timespec
  		var nsec int32
  		ns += nanotime()
  		ts.set_sec(timediv(ns, 1000000000, &nsec))
  		ts.set_nsec(nsec)
  		tsp = &ts
  	}
  
  	for {
  		v := atomic.Load(&_g_.m.waitsemacount)
  		if v > 0 {
  			if atomic.Cas(&_g_.m.waitsemacount, v, v-1) {
  				return 0 // semaphore acquired
  			}
  			continue
  		}
  
  		// Sleep until unparked by semawakeup or timeout.
  		ret := lwp_park(tsp, 0, unsafe.Pointer(&_g_.m.waitsemacount), nil)
  		if ret == _ETIMEDOUT {
  			return -1
  		}
  	}
  }
  
  //go:nosplit
  func semawakeup(mp *m) {
  	atomic.Xadd(&mp.waitsemacount, 1)
  	// From NetBSD's _lwp_unpark(2) manual:
  	// "If the target LWP is not currently waiting, it will return
  	// immediately upon the next call to _lwp_park()."
  	ret := lwp_unpark(int32(mp.procid), unsafe.Pointer(&mp.waitsemacount))
  	if ret != 0 && ret != _ESRCH {
  		// semawakeup can be called on signal stack.
  		systemstack(func() {
  			print("thrwakeup addr=", &mp.waitsemacount, " sem=", mp.waitsemacount, " ret=", ret, "\n")
  		})
  	}
  }
  
  // May run with m.p==nil, so write barriers are not allowed.
  //go:nowritebarrier
  func newosproc(mp *m, stk unsafe.Pointer) {
  	if false {
  		print("newosproc stk=", stk, " m=", mp, " g=", mp.g0, " id=", mp.id, " ostk=", &mp, "\n")
  	}
  
  	var uc ucontextt
  	getcontext(unsafe.Pointer(&uc))
  
  	// _UC_SIGMASK does not seem to work here.
  	// It would be nice if _UC_SIGMASK and _UC_STACK
  	// worked so that we could do all the work setting
  	// the sigmask and the stack here, instead of setting
  	// the mask here and the stack in netbsdMstart.
  	// For now do the blocking manually.
  	uc.uc_flags = _UC_SIGMASK | _UC_CPU
  	uc.uc_link = nil
  	uc.uc_sigmask = sigset_all
  
  	var oset sigset
  	sigprocmask(_SIG_SETMASK, &sigset_all, &oset)
  
  	lwp_mcontext_init(&uc.uc_mcontext, stk, mp, mp.g0, funcPC(netbsdMstart))
  
  	ret := lwp_create(unsafe.Pointer(&uc), 0, unsafe.Pointer(&mp.procid))
  	sigprocmask(_SIG_SETMASK, &oset, nil)
  	if ret < 0 {
  		print("runtime: failed to create new OS thread (have ", mcount()-1, " already; errno=", -ret, ")\n")
  		if ret == -_EAGAIN {
  			println("runtime: may need to increase max user processes (ulimit -p)")
  		}
  		throw("runtime.newosproc")
  	}
  }
  
  // netbsdMStart is the function call that starts executing a newly
  // created thread. On NetBSD, a new thread inherits the signal stack
  // of the creating thread. That confuses minit, so we remove that
  // signal stack here before calling the regular mstart. It's a bit
  // baroque to remove a signal stack here only to add one in minit, but
  // it's a simple change that keeps NetBSD working like other OS's.
  // At this point all signals are blocked, so there is no race.
  //go:nosplit
  func netbsdMstart() {
  	st := stackt{ss_flags: _SS_DISABLE}
  	sigaltstack(&st, nil)
  	mstart()
  }
  
  func osinit() {
  	ncpu = getncpu()
  	physPageSize = getPageSize()
  }
  
  var urandom_dev = []byte("/dev/urandom\x00")
  
  //go:nosplit
  func getRandomData(r []byte) {
  	fd := open(&urandom_dev[0], 0 /* O_RDONLY */, 0)
  	n := read(fd, unsafe.Pointer(&r[0]), int32(len(r)))
  	closefd(fd)
  	extendRandom(r, int(n))
  }
  
  func goenvs() {
  	goenvs_unix()
  }
  
  // Called to initialize a new m (including the bootstrap m).
  // Called on the parent thread (main thread in case of bootstrap), can allocate memory.
  func mpreinit(mp *m) {
  	mp.gsignal = malg(32 * 1024)
  	mp.gsignal.m = mp
  }
  
  // Called to initialize a new m (including the bootstrap m).
  // Called on the new thread, cannot allocate memory.
  func minit() {
  	_g_ := getg()
  	_g_.m.procid = uint64(lwp_self())
  
  	// On NetBSD a thread created by pthread_create inherits the
  	// signal stack of the creating thread. We always create a
  	// new signal stack here, to avoid having two Go threads using
  	// the same signal stack. This breaks the case of a thread
  	// created in C that calls sigaltstack and then calls a Go
  	// function, because we will lose track of the C code's
  	// sigaltstack, but it's the best we can do.
  	signalstack(&_g_.m.gsignal.stack)
  	_g_.m.newSigstack = true
  
  	minitSignalMask()
  }
  
  // Called from dropm to undo the effect of an minit.
  //go:nosplit
  func unminit() {
  	unminitSignals()
  }
  
  func memlimit() uintptr {
  	return 0
  }
  
  func sigtramp()
  
  type sigactiont struct {
  	sa_sigaction uintptr
  	sa_mask      sigset
  	sa_flags     int32
  }
  
  //go:nosplit
  //go:nowritebarrierrec
  func setsig(i uint32, fn uintptr) {
  	var sa sigactiont
  	sa.sa_flags = _SA_SIGINFO | _SA_ONSTACK | _SA_RESTART
  	sa.sa_mask = sigset_all
  	if fn == funcPC(sighandler) {
  		fn = funcPC(sigtramp)
  	}
  	sa.sa_sigaction = fn
  	sigaction(i, &sa, nil)
  }
  
  //go:nosplit
  //go:nowritebarrierrec
  func setsigstack(i uint32) {
  	throw("setsigstack")
  }
  
  //go:nosplit
  //go:nowritebarrierrec
  func getsig(i uint32) uintptr {
  	var sa sigactiont
  	sigaction(i, nil, &sa)
  	return sa.sa_sigaction
  }
  
  // setSignaltstackSP sets the ss_sp field of a stackt.
  //go:nosplit
  func setSignalstackSP(s *stackt, sp uintptr) {
  	s.ss_sp = sp
  }
  
  //go:nosplit
  //go:nowritebarrierrec
  func sigaddset(mask *sigset, i int) {
  	mask.__bits[(i-1)/32] |= 1 << ((uint32(i) - 1) & 31)
  }
  
  func sigdelset(mask *sigset, i int) {
  	mask.__bits[(i-1)/32] &^= 1 << ((uint32(i) - 1) & 31)
  }
  
  func (c *sigctxt) fixsigcode(sig uint32) {
  }
  

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