//  v5.1: pidfd_send_signal syscall;
//  v5.2: CLONE_PIDFD flag for clone syscall;
//  v5.3: pidfd_open syscall, clone3 syscall;
//  v5.4: P_PIDFD idtype support for waitid syscall;
//  v5.6: pidfd_getfd syscall.

package os

import (
	"errors"
	"internal/syscall/unix"
	"sync"
	"syscall"
	"unsafe"
)

func ensurePidfd(sysAttr *syscall.SysProcAttr) *syscall.SysProcAttr {
	if !pidfdWorks() {

// Copyright 2023 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.

// Tests syscall P stealing from a goroutine and thread
// that have been in a syscall the entire generation.

package main

import (
	"internal/trace"
	"internal/trace/event/go122"
	testgen "internal/trace/internal/testgen/go122"
)

func main() {
	testgen.Main(gen)
}

// Copyright 2023 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.

// Tests syscall P stealing.
//
// Specifically, it tests a scenario where a thread 'steals'
// a P from itself. It's just a ProcStop with extra steps when
// it happens on the same P.

package main

import (
	"internal/trace"
	"internal/trace/event/go122"

	EvGoSysCall         = 28 // syscall enter [timestamp, stack]
	EvGoSysExit         = 29 // syscall exit [timestamp, goroutine id, seq, real timestamp]
	EvGoSysBlock        = 30 // syscall blocks [timestamp]
	EvGoWaiting         = 31 // denotes that goroutine is blocked when tracing starts [timestamp, goroutine id]
	EvGoInSyscall       = 32 // denotes that goroutine is in syscall when tracing starts [timestamp, goroutine id]

// Copyright 2023 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.

// Tests syscall P stealing.
//
// Specifically, it tests a scenerio wherein, without a
// P sequence number of GoSyscallBegin, the syscall that
// a ProcSteal applies to is ambiguous. This only happens in
// practice when the events aren't already properly ordered

// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

// Tests a G being created from within a syscall.
//
// Specifically, it tests a scenerio wherein a C
// thread is calling into Go, creating a goroutine in
// a syscall (in the tracer's model). Because the actual
// m can be reused, it's possible for that m to have never
// had its P (in _Psyscall) stolen if the runtime doesn't

// license that can be found in the LICENSE file.

// Tests syscall P stealing at a generation boundary.

package main

import (
	"internal/trace"
	"internal/trace/event/go122"
	testgen "internal/trace/internal/testgen/go122"
)

func main() {
	testgen.Main(gen)
}

func gen(t *testgen.Trace) {
	g := t.Generation(1)

	// One goroutine is exiting with a syscall. It already
	// acquired a new P.

// license that can be found in the LICENSE file.

// Tests syscall P stealing.

package main

import (
	"internal/trace"
	"internal/trace/event/go122"
	testgen "internal/trace/internal/testgen/go122"
)

func main() {
	testgen.Main(gen)
}

func gen(t *testgen.Trace) {
	g := t.Generation(1)

	// One goroutine enters a syscall, grabs a P, and starts running.
	b0 := g.Batch(trace.ThreadID(0), 0)

// license that can be found in the LICENSE file.

// Tests syscall P stealing.

package main

import (
	"internal/trace"
	"internal/trace/event/go122"
	testgen "internal/trace/internal/testgen/go122"
)

func main() {
	testgen.Main(gen)
}

func gen(t *testgen.Trace) {
	g := t.Generation(1)

	// One goroutine enters a syscall.
	b0 := g.Batch(trace.ThreadID(0), 0)

// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

// Tests a G being created from within a syscall.
//
// Specifically, it tests a scenerio wherein a C
// thread is calling into Go, creating a goroutine in
// a syscall (in the tracer's model). The system is free
// to reuse thread IDs, so first a thread ID is used to
// call into Go, and then is used for a Go-created thread.
//