Adding upstream version 1.16.10.upstream/1.16.10upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 199 insertions, 0 deletions

diff --git a/src/runtime/export_debug_test.go b/src/runtime/export_debug_test.go
new file mode 100644
index 0000000..ed4242e
--- /dev/null
+++ b/src/runtime/export_debug_test.go
@@ -0,0 +1,199 @@
+// Copyright 2018 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.
+
+// +build amd64
+// +build linux
+
+package runtime
+
+import (
+	"runtime/internal/sys"
+	"unsafe"
+)
+
+// InjectDebugCall injects a debugger call to fn into g. args must be
+// a pointer to a valid call frame (including arguments and return
+// space) for fn, or nil. tkill must be a function that will send
+// SIGTRAP to thread ID tid. gp must be locked to its OS thread and
+// running.
+//
+// On success, InjectDebugCall returns the panic value of fn or nil.
+// If fn did not panic, its results will be available in args.
+func InjectDebugCall(gp *g, fn, args interface{}, tkill func(tid int) error, returnOnUnsafePoint bool) (interface{}, error) {
+	if gp.lockedm == 0 {
+		return nil, plainError("goroutine not locked to thread")
+	}
+
+	tid := int(gp.lockedm.ptr().procid)
+	if tid == 0 {
+		return nil, plainError("missing tid")
+	}
+
+	f := efaceOf(&fn)
+	if f._type == nil || f._type.kind&kindMask != kindFunc {
+		return nil, plainError("fn must be a function")
+	}
+	fv := (*funcval)(f.data)
+
+	a := efaceOf(&args)
+	if a._type != nil && a._type.kind&kindMask != kindPtr {
+		return nil, plainError("args must be a pointer or nil")
+	}
+	argp := a.data
+	var argSize uintptr
+	if argp != nil {
+		argSize = (*ptrtype)(unsafe.Pointer(a._type)).elem.size
+	}
+
+	h := new(debugCallHandler)
+	h.gp = gp
+	// gp may not be running right now, but we can still get the M
+	// it will run on since it's locked.
+	h.mp = gp.lockedm.ptr()
+	h.fv, h.argp, h.argSize = fv, argp, argSize
+	h.handleF = h.handle // Avoid allocating closure during signal
+
+	defer func() { testSigtrap = nil }()
+	for i := 0; ; i++ {
+		testSigtrap = h.inject
+		noteclear(&h.done)
+		h.err = ""
+
+		if err := tkill(tid); err != nil {
+			return nil, err
+		}
+		// Wait for completion.
+		notetsleepg(&h.done, -1)
+		if h.err != "" {
+			switch h.err {
+			case "call not at safe point":
+				if returnOnUnsafePoint {
+					// This is for TestDebugCallUnsafePoint.
+					return nil, h.err
+				}
+				fallthrough
+			case "retry _Grunnable", "executing on Go runtime stack", "call from within the Go runtime":
+				// These are transient states. Try to get out of them.
+				if i < 100 {
+					usleep(100)
+					Gosched()
+					continue
+				}
+			}
+			return nil, h.err
+		}
+		return h.panic, nil
+	}
+}
+
+type debugCallHandler struct {
+	gp      *g
+	mp      *m
+	fv      *funcval
+	argp    unsafe.Pointer
+	argSize uintptr
+	panic   interface{}
+
+	handleF func(info *siginfo, ctxt *sigctxt, gp2 *g) bool
+
+	err       plainError
+	done      note
+	savedRegs sigcontext
+	savedFP   fpstate1
+}
+
+func (h *debugCallHandler) inject(info *siginfo, ctxt *sigctxt, gp2 *g) bool {
+	switch h.gp.atomicstatus {
+	case _Grunning:
+		if getg().m != h.mp {
+			println("trap on wrong M", getg().m, h.mp)
+			return false
+		}
+		// Push current PC on the stack.
+		rsp := ctxt.rsp() - sys.PtrSize
+		*(*uint64)(unsafe.Pointer(uintptr(rsp))) = ctxt.rip()
+		ctxt.set_rsp(rsp)
+		// Write the argument frame size.
+		*(*uintptr)(unsafe.Pointer(uintptr(rsp - 16))) = h.argSize
+		// Save current registers.
+		h.savedRegs = *ctxt.regs()
+		h.savedFP = *h.savedRegs.fpstate
+		h.savedRegs.fpstate = nil
+		// Set PC to debugCallV1.
+		ctxt.set_rip(uint64(funcPC(debugCallV1)))
+		// Call injected. Switch to the debugCall protocol.
+		testSigtrap = h.handleF
+	case _Grunnable:
+		// Ask InjectDebugCall to pause for a bit and then try
+		// again to interrupt this goroutine.
+		h.err = plainError("retry _Grunnable")
+		notewakeup(&h.done)
+	default:
+		h.err = plainError("goroutine in unexpected state at call inject")
+		notewakeup(&h.done)
+	}
+	// Resume execution.
+	return true
+}
+
+func (h *debugCallHandler) handle(info *siginfo, ctxt *sigctxt, gp2 *g) bool {
+	// Sanity check.
+	if getg().m != h.mp {
+		println("trap on wrong M", getg().m, h.mp)
+		return false
+	}
+	f := findfunc(uintptr(ctxt.rip()))
+	if !(hasPrefix(funcname(f), "runtime.debugCall") || hasPrefix(funcname(f), "debugCall")) {
+		println("trap in unknown function", funcname(f))
+		return false
+	}
+	if *(*byte)(unsafe.Pointer(uintptr(ctxt.rip() - 1))) != 0xcc {
+		println("trap at non-INT3 instruction pc =", hex(ctxt.rip()))
+		return false
+	}
+
+	switch status := ctxt.rax(); status {
+	case 0:
+		// Frame is ready. Copy the arguments to the frame.
+		sp := ctxt.rsp()
+		memmove(unsafe.Pointer(uintptr(sp)), h.argp, h.argSize)
+		// Push return PC.
+		sp -= sys.PtrSize
+		ctxt.set_rsp(sp)
+		*(*uint64)(unsafe.Pointer(uintptr(sp))) = ctxt.rip()
+		// Set PC to call and context register.
+		ctxt.set_rip(uint64(h.fv.fn))
+		ctxt.regs().rcx = uint64(uintptr(unsafe.Pointer(h.fv)))
+	case 1:
+		// Function returned. Copy frame back out.
+		sp := ctxt.rsp()
+		memmove(h.argp, unsafe.Pointer(uintptr(sp)), h.argSize)
+	case 2:
+		// Function panicked. Copy panic out.
+		sp := ctxt.rsp()
+		memmove(unsafe.Pointer(&h.panic), unsafe.Pointer(uintptr(sp)), 2*sys.PtrSize)
+	case 8:
+		// Call isn't safe. Get the reason.
+		sp := ctxt.rsp()
+		reason := *(*string)(unsafe.Pointer(uintptr(sp)))
+		h.err = plainError(reason)
+		// Don't wake h.done. We need to transition to status 16 first.
+	case 16:
+		// Restore all registers except RIP and RSP.
+		rip, rsp := ctxt.rip(), ctxt.rsp()
+		fp := ctxt.regs().fpstate
+		*ctxt.regs() = h.savedRegs
+		ctxt.regs().fpstate = fp
+		*fp = h.savedFP
+		ctxt.set_rip(rip)
+		ctxt.set_rsp(rsp)
+		// Done
+		notewakeup(&h.done)
+	default:
+		h.err = plainError("unexpected debugCallV1 status")
+		notewakeup(&h.done)
+	}
+	// Resume execution.
+	return true
+}