src/pkg/exp/ogle/process.go - go - Git at Google

 // Copyright 2009 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 ogle

 import (
 	"debug/elf"
 	"debug/gosym"
 	"debug/proc"
 	"exp/eval"
 	"fmt"
 	"log"
 	"os"
 	"reflect"
 )

 // A FormatError indicates a failure to process information in or
 // about a remote process, such as unexpected or missing information
 // in the object file or runtime structures.
 type FormatError string

 func (e FormatError) String() string { return string(e) }

 // An UnknownArchitecture occurs when trying to load an object file
 // that indicates an architecture not supported by the debugger.
 type UnknownArchitecture elf.Machine

 func (e UnknownArchitecture) String() string {
 	return "unknown architecture: " + elf.Machine(e).String()
 }

 // A ProcessNotStopped error occurs when attempting to read or write
 // memory or registers of a process that is not stopped.
 type ProcessNotStopped struct{}

 func (e ProcessNotStopped) String() string { return "process not stopped" }

 // An UnknownGoroutine error is an internal error representing an
 // unrecognized G structure pointer.
 type UnknownGoroutine struct {
 	OSThread  proc.Thread
 	Goroutine proc.Word
 }

 func (e UnknownGoroutine) String() string {
 	return fmt.Sprintf("internal error: unknown goroutine (G %#x)", e.Goroutine)
 }

 // A NoCurrentGoroutine error occurs when no goroutine is currently
 // selected in a process (or when there are no goroutines in a
 // process).
 type NoCurrentGoroutine struct{}

 func (e NoCurrentGoroutine) String() string { return "no current goroutine" }

 // A Process represents a remote attached process.
 type Process struct {
 	Arch
 	proc proc.Process

 	// The symbol table of this process
 	syms *gosym.Table

 	// A possibly-stopped OS thread, or nil
 	threadCache proc.Thread

 	// Types parsed from the remote process
 	types map[proc.Word]*remoteType

 	// Types and values from the remote runtime package
 	runtime runtimeValues

 	// Runtime field indexes
 	f runtimeIndexes

 	// Globals from the sys package (or from no package)
 	sys struct {
 		lessstack, goexit, newproc, deferproc, newprocreadylocked *gosym.Func
 		allg                                                      remotePtr
 		g0                                                        remoteStruct
 	}

 	// Event queue
 	posted  []Event
 	pending []Event
 	event   Event

 	// Event hooks
 	breakpointHooks     map[proc.Word]*breakpointHook
 	goroutineCreateHook *goroutineCreateHook
 	goroutineExitHook   *goroutineExitHook

 	// Current goroutine, or nil if there are no goroutines
 	curGoroutine *Goroutine

 	// Goroutines by the address of their G structure
 	goroutines map[proc.Word]*Goroutine
 }

 /*
  * Process creation
  */

 // NewProcess constructs a new remote process around a traced
 // process, an architecture, and a symbol table.
 func NewProcess(tproc proc.Process, arch Arch, syms *gosym.Table) (*Process, os.Error) {
 	p := &Process{
 		Arch:                arch,
 		proc:                tproc,
 		syms:                syms,
 		types:               make(map[proc.Word]*remoteType),
 		breakpointHooks:     make(map[proc.Word]*breakpointHook),
 		goroutineCreateHook: new(goroutineCreateHook),
 		goroutineExitHook:   new(goroutineExitHook),
 		goroutines:          make(map[proc.Word]*Goroutine),
 	}

 	// Fill in remote runtime
 	p.bootstrap()

 	switch {
 	case p.sys.allg.addr().base == 0:
 		return nil, FormatError("failed to find runtime symbol 'allg'")
 	case p.sys.g0.addr().base == 0:
 		return nil, FormatError("failed to find runtime symbol 'g0'")
 	case p.sys.newprocreadylocked == nil:
 		return nil, FormatError("failed to find runtime symbol 'newprocreadylocked'")
 	case p.sys.goexit == nil:
 		return nil, FormatError("failed to find runtime symbol 'sys.goexit'")
 	}

 	// Get current goroutines
 	p.goroutines[p.sys.g0.addr().base] = &Goroutine{p.sys.g0, nil, false}
 	err := try(func(a aborter) {
 		g := p.sys.allg.aGet(a)
 		for g != nil {
 			gs := g.(remoteStruct)
 			fmt.Printf("*** Found goroutine at %#x\n", gs.addr().base)
 			p.goroutines[gs.addr().base] = &Goroutine{gs, nil, false}
 			g = gs.field(p.f.G.Alllink).(remotePtr).aGet(a)
 		}
 	})
 	if err != nil {
 		return nil, err
 	}

 	// Create internal breakpoints to catch new and exited goroutines
 	p.OnBreakpoint(proc.Word(p.sys.newprocreadylocked.Entry)).(*breakpointHook).addHandler(readylockedBP, true)
 	p.OnBreakpoint(proc.Word(p.sys.goexit.Entry)).(*breakpointHook).addHandler(goexitBP, true)

 	// Select current frames
 	for _, g := range p.goroutines {
 		g.resetFrame()
 	}

 	p.selectSomeGoroutine()

 	return p, nil
 }

 func elfGoSyms(f *elf.File) (*gosym.Table, os.Error) {
 	text := f.Section(".text")
 	symtab := f.Section(".gosymtab")
 	pclntab := f.Section(".gopclntab")
 	if text == nil || symtab == nil || pclntab == nil {
 		return nil, nil
 	}

 	symdat, err := symtab.Data()
 	if err != nil {
 		return nil, err
 	}
 	pclndat, err := pclntab.Data()
 	if err != nil {
 		return nil, err
 	}

 	pcln := gosym.NewLineTable(pclndat, text.Addr)
 	tab, err := gosym.NewTable(symdat, pcln)
 	if err != nil {
 		return nil, err
 	}

 	return tab, nil
 }

 // NewProcessElf constructs a new remote process around a traced
 // process and the process' ELF object.
 func NewProcessElf(tproc proc.Process, f *elf.File) (*Process, os.Error) {
 	syms, err := elfGoSyms(f)
 	if err != nil {
 		return nil, err
 	}
 	if syms == nil {
 		return nil, FormatError("Failed to find symbol table")
 	}
 	var arch Arch
 	switch f.Machine {
 	case elf.EM_X86_64:
 		arch = Amd64
 	default:
 		return nil, UnknownArchitecture(f.Machine)
 	}
 	return NewProcess(tproc, arch, syms)
 }

 // bootstrap constructs the runtime structure of a remote process.
 func (p *Process) bootstrap() {
 	// Manually construct runtime types
 	p.runtime.String = newManualType(eval.TypeOfNative(rt1String{}), p.Arch)
 	p.runtime.Slice = newManualType(eval.TypeOfNative(rt1Slice{}), p.Arch)
 	p.runtime.Eface = newManualType(eval.TypeOfNative(rt1Eface{}), p.Arch)

 	p.runtime.Type = newManualType(eval.TypeOfNative(rt1Type{}), p.Arch)
 	p.runtime.CommonType = newManualType(eval.TypeOfNative(rt1CommonType{}), p.Arch)
 	p.runtime.UncommonType = newManualType(eval.TypeOfNative(rt1UncommonType{}), p.Arch)
 	p.runtime.StructField = newManualType(eval.TypeOfNative(rt1StructField{}), p.Arch)
 	p.runtime.StructType = newManualType(eval.TypeOfNative(rt1StructType{}), p.Arch)
 	p.runtime.PtrType = newManualType(eval.TypeOfNative(rt1PtrType{}), p.Arch)
 	p.runtime.ArrayType = newManualType(eval.TypeOfNative(rt1ArrayType{}), p.Arch)
 	p.runtime.SliceType = newManualType(eval.TypeOfNative(rt1SliceType{}), p.Arch)

 	p.runtime.Stktop = newManualType(eval.TypeOfNative(rt1Stktop{}), p.Arch)
 	p.runtime.Gobuf = newManualType(eval.TypeOfNative(rt1Gobuf{}), p.Arch)
 	p.runtime.G = newManualType(eval.TypeOfNative(rt1G{}), p.Arch)

 	// Get addresses of type.*runtime.XType for discrimination.
 	rtv := reflect.Indirect(reflect.ValueOf(&p.runtime))
 	rtvt := rtv.Type()
 	for i := 0; i < rtv.NumField(); i++ {
 		n := rtvt.Field(i).Name
 		if n[0] != 'P' || n[1] < 'A' || n[1] > 'Z' {
 			continue
 		}
 		sym := p.syms.LookupSym("type.*runtime." + n[1:])
 		if sym == nil {
 			continue
 		}
 		rtv.Field(i).SetUint(sym.Value)
 	}

 	// Get runtime field indexes
 	fillRuntimeIndexes(&p.runtime, &p.f)

 	// Fill G status
 	p.runtime.runtimeGStatus = rt1GStatus

 	// Get globals
 	p.sys.lessstack = p.syms.LookupFunc("sys.lessstack")
 	p.sys.goexit = p.syms.LookupFunc("goexit")
 	p.sys.newproc = p.syms.LookupFunc("sys.newproc")
 	p.sys.deferproc = p.syms.LookupFunc("sys.deferproc")
 	p.sys.newprocreadylocked = p.syms.LookupFunc("newprocreadylocked")
 	if allg := p.syms.LookupSym("allg"); allg != nil {
 		p.sys.allg = remotePtr{remote{proc.Word(allg.Value), p}, p.runtime.G}
 	}
 	if g0 := p.syms.LookupSym("g0"); g0 != nil {
 		p.sys.g0 = p.runtime.G.mk(remote{proc.Word(g0.Value), p}).(remoteStruct)
 	}
 }

 func (p *Process) selectSomeGoroutine() {
 	// Once we have friendly goroutine ID's, there might be a more
 	// reasonable behavior for this.
 	p.curGoroutine = nil
 	for _, g := range p.goroutines {
 		if !g.isG0() && g.frame != nil {
 			p.curGoroutine = g
 			return
 		}
 	}
 }

 /*
  * Process memory
  */

 func (p *Process) someStoppedOSThread() proc.Thread {
 	if p.threadCache != nil {
 		if _, err := p.threadCache.Stopped(); err == nil {
 			return p.threadCache
 		}
 	}

 	for _, t := range p.proc.Threads() {
 		if _, err := t.Stopped(); err == nil {
 			p.threadCache = t
 			return t
 		}
 	}
 	return nil
 }

 func (p *Process) Peek(addr proc.Word, out []byte) (int, os.Error) {
 	thr := p.someStoppedOSThread()
 	if thr == nil {
 		return 0, ProcessNotStopped{}
 	}
 	return thr.Peek(addr, out)
 }

 func (p *Process) Poke(addr proc.Word, b []byte) (int, os.Error) {
 	thr := p.someStoppedOSThread()
 	if thr == nil {
 		return 0, ProcessNotStopped{}
 	}
 	return thr.Poke(addr, b)
 }

 func (p *Process) peekUintptr(a aborter, addr proc.Word) proc.Word {
 	return proc.Word(mkUintptr(remote{addr, p}).(remoteUint).aGet(a))
 }

 /*
  * Events
  */

 // OnBreakpoint returns the hook that is run when the program reaches
 // the given program counter.
 func (p *Process) OnBreakpoint(pc proc.Word) EventHook {
 	if bp, ok := p.breakpointHooks[pc]; ok {
 		return bp
 	}
 	// The breakpoint will register itself when a handler is added
 	return &breakpointHook{commonHook{nil, 0}, p, pc}
 }

 // OnGoroutineCreate returns the hook that is run when a goroutine is created.
 func (p *Process) OnGoroutineCreate() EventHook {
 	return p.goroutineCreateHook
 }

 // OnGoroutineExit returns the hook that is run when a goroutine exits.
 func (p *Process) OnGoroutineExit() EventHook { return p.goroutineExitHook }

 // osThreadToGoroutine looks up the goroutine running on an OS thread.
 func (p *Process) osThreadToGoroutine(t proc.Thread) (*Goroutine, os.Error) {
 	regs, err := t.Regs()
 	if err != nil {
 		return nil, err
 	}
 	g := p.G(regs)
 	gt, ok := p.goroutines[g]
 	if !ok {
 		return nil, UnknownGoroutine{t, g}
 	}
 	return gt, nil
 }

 // causesToEvents translates the stop causes of the underlying process
 // into an event queue.
 func (p *Process) causesToEvents() ([]Event, os.Error) {
 	// Count causes we're interested in
 	nev := 0
 	for _, t := range p.proc.Threads() {
 		if c, err := t.Stopped(); err == nil {
 			switch c := c.(type) {
 			case proc.Breakpoint:
 				nev++
 			case proc.Signal:
 				// TODO(austin)
 				//nev++;
 			}
 		}
 	}

 	// Translate causes to events
 	events := make([]Event, nev)
 	i := 0
 	for _, t := range p.proc.Threads() {
 		if c, err := t.Stopped(); err == nil {
 			switch c := c.(type) {
 			case proc.Breakpoint:
 				gt, err := p.osThreadToGoroutine(t)
 				if err != nil {
 					return nil, err
 				}
 				events[i] = &Breakpoint{commonEvent{p, gt}, t, proc.Word(c)}
 				i++
 			case proc.Signal:
 				// TODO(austin)
 			}
 		}
 	}

 	return events, nil
 }

 // postEvent appends an event to the posted queue.  These events will
 // be processed before any currently pending events.
 func (p *Process) postEvent(ev Event) {
 	p.posted = append(p.posted, ev)
 }

 // processEvents processes events in the event queue until no events
 // remain, a handler returns EAStop, or a handler returns an error.
 // It returns either EAStop or EAContinue and possibly an error.
 func (p *Process) processEvents() (EventAction, os.Error) {
 	var ev Event
 	for len(p.posted) > 0 {
 		ev, p.posted = p.posted[0], p.posted[1:]
 		action, err := p.processEvent(ev)
 		if action == EAStop {
 			return action, err
 		}
 	}

 	for len(p.pending) > 0 {
 		ev, p.pending = p.pending[0], p.pending[1:]
 		action, err := p.processEvent(ev)
 		if action == EAStop {
 			return action, err
 		}
 	}

 	return EAContinue, nil
 }

 // processEvent processes a single event, without manipulating the
 // event queues.  It returns either EAStop or EAContinue and possibly
 // an error.
 func (p *Process) processEvent(ev Event) (EventAction, os.Error) {
 	p.event = ev

 	var action EventAction
 	var err os.Error
 	switch ev := p.event.(type) {
 	case *Breakpoint:
 		hook, ok := p.breakpointHooks[ev.pc]
 		if !ok {
 			break
 		}
 		p.curGoroutine = ev.Goroutine()
 		action, err = hook.handle(ev)

 	case *GoroutineCreate:
 		p.curGoroutine = ev.Goroutine()
 		action, err = p.goroutineCreateHook.handle(ev)

 	case *GoroutineExit:
 		action, err = p.goroutineExitHook.handle(ev)

 	default:
 		log.Panicf("Unknown event type %T in queue", p.event)
 	}

 	if err != nil {
 		return EAStop, err
 	} else if action == EAStop {
 		return EAStop, nil
 	}
 	return EAContinue, nil
 }

 // Event returns the last event that caused the process to stop.  This
 // may return nil if the process has never been stopped by an event.
 //
 // TODO(austin) Return nil if the user calls p.Stop()?
 func (p *Process) Event() Event { return p.event }

 /*
  * Process control
  */

 // TODO(austin) Cont, WaitStop, and Stop.  Need to figure out how
 // event handling works with these.  Originally I did it only in
 // WaitStop, but if you Cont and there are pending events, then you
 // have to not actually continue and wait until a WaitStop to process
 // them, even if the event handlers will tell you to continue.  We
 // could handle them in both Cont and WaitStop to avoid this problem,
 // but it's still weird if an event happens after the Cont and before
 // the WaitStop that the handlers say to continue from.  Or we could
 // handle them on a separate thread.  Then obviously you get weird
 // asynchronous things, like prints while the user it typing a command,
 // but that's not necessarily a bad thing.

 // ContWait resumes process execution and waits for an event to occur
 // that stops the process.
 func (p *Process) ContWait() os.Error {
 	for {
 		a, err := p.processEvents()
 		if err != nil {
 			return err
 		} else if a == EAStop {
 			break
 		}
 		err = p.proc.Continue()
 		if err != nil {
 			return err
 		}
 		err = p.proc.WaitStop()
 		if err != nil {
 			return err
 		}
 		for _, g := range p.goroutines {
 			g.resetFrame()
 		}
 		p.pending, err = p.causesToEvents()
 		if err != nil {
 			return err
 		}
 	}
 	return nil
 }

 // Out selects the caller frame of the current frame.
 func (p *Process) Out() os.Error {
 	if p.curGoroutine == nil {
 		return NoCurrentGoroutine{}
 	}
 	return p.curGoroutine.Out()
 }

 // In selects the frame called by the current frame.
 func (p *Process) In() os.Error {
 	if p.curGoroutine == nil {
 		return NoCurrentGoroutine{}
 	}
 	return p.curGoroutine.In()
 }
	// Copyright 2009 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 ogle

	import (
	"debug/elf"
	"debug/gosym"
	"debug/proc"
	"exp/eval"
	"fmt"
	"log"
	"os"
	"reflect"
	)

	// A FormatError indicates a failure to process information in or
	// about a remote process, such as unexpected or missing information
	// in the object file or runtime structures.
	type FormatError string

	func (e FormatError) String() string { return string(e) }

	// An UnknownArchitecture occurs when trying to load an object file
	// that indicates an architecture not supported by the debugger.
	type UnknownArchitecture elf.Machine

	func (e UnknownArchitecture) String() string {
	return "unknown architecture: " + elf.Machine(e).String()
	}

	// A ProcessNotStopped error occurs when attempting to read or write
	// memory or registers of a process that is not stopped.
	type ProcessNotStopped struct{}

	func (e ProcessNotStopped) String() string { return "process not stopped" }

	// An UnknownGoroutine error is an internal error representing an
	// unrecognized G structure pointer.
	type UnknownGoroutine struct {
	OSThread proc.Thread
	Goroutine proc.Word
	}

	func (e UnknownGoroutine) String() string {
	return fmt.Sprintf("internal error: unknown goroutine (G %#x)", e.Goroutine)
	}

	// A NoCurrentGoroutine error occurs when no goroutine is currently
	// selected in a process (or when there are no goroutines in a
	// process).
	type NoCurrentGoroutine struct{}

	func (e NoCurrentGoroutine) String() string { return "no current goroutine" }

	// A Process represents a remote attached process.
	type Process struct {
	Arch
	proc proc.Process

	// The symbol table of this process
	syms *gosym.Table

	// A possibly-stopped OS thread, or nil
	threadCache proc.Thread

	// Types parsed from the remote process
	types map[proc.Word]*remoteType

	// Types and values from the remote runtime package
	runtime runtimeValues

	// Runtime field indexes
	f runtimeIndexes

	// Globals from the sys package (or from no package)
	sys struct {
	lessstack, goexit, newproc, deferproc, newprocreadylocked *gosym.Func
	allg remotePtr
	g0 remoteStruct
	}

	// Event queue
	posted []Event
	pending []Event
	event Event

	// Event hooks
	breakpointHooks map[proc.Word]*breakpointHook
	goroutineCreateHook *goroutineCreateHook
	goroutineExitHook *goroutineExitHook

	// Current goroutine, or nil if there are no goroutines
	curGoroutine *Goroutine

	// Goroutines by the address of their G structure
	goroutines map[proc.Word]*Goroutine
	}

	/*
	* Process creation
	*/

	// NewProcess constructs a new remote process around a traced
	// process, an architecture, and a symbol table.
	func NewProcess(tproc proc.Process, arch Arch, syms gosym.Table) (Process, os.Error) {
	p := &Process{
	Arch: arch,
	proc: tproc,
	syms: syms,
	types: make(map[proc.Word]*remoteType),
	breakpointHooks: make(map[proc.Word]*breakpointHook),
	goroutineCreateHook: new(goroutineCreateHook),
	goroutineExitHook: new(goroutineExitHook),
	goroutines: make(map[proc.Word]*Goroutine),
	}

	// Fill in remote runtime
	p.bootstrap()

	switch {
	case p.sys.allg.addr().base == 0:
	return nil, FormatError("failed to find runtime symbol 'allg'")
	case p.sys.g0.addr().base == 0:
	return nil, FormatError("failed to find runtime symbol 'g0'")
	case p.sys.newprocreadylocked == nil:
	return nil, FormatError("failed to find runtime symbol 'newprocreadylocked'")
	case p.sys.goexit == nil:
	return nil, FormatError("failed to find runtime symbol 'sys.goexit'")
	}

	// Get current goroutines
	p.goroutines[p.sys.g0.addr().base] = &Goroutine{p.sys.g0, nil, false}
	err := try(func(a aborter) {
	g := p.sys.allg.aGet(a)
	for g != nil {
	gs := g.(remoteStruct)
	fmt.Printf("*** Found goroutine at %#x\n", gs.addr().base)
	p.goroutines[gs.addr().base] = &Goroutine{gs, nil, false}
	g = gs.field(p.f.G.Alllink).(remotePtr).aGet(a)
	}
	})
	if err != nil {
	return nil, err
	}

	// Create internal breakpoints to catch new and exited goroutines
	p.OnBreakpoint(proc.Word(p.sys.newprocreadylocked.Entry)).(*breakpointHook).addHandler(readylockedBP, true)
	p.OnBreakpoint(proc.Word(p.sys.goexit.Entry)).(*breakpointHook).addHandler(goexitBP, true)

	// Select current frames
	for _, g := range p.goroutines {
	g.resetFrame()
	}

	p.selectSomeGoroutine()

	return p, nil
	}

	func elfGoSyms(f elf.File) (gosym.Table, os.Error) {
	text := f.Section(".text")
	symtab := f.Section(".gosymtab")
	pclntab := f.Section(".gopclntab")
	if text == nil \|\| symtab == nil \|\| pclntab == nil {
	return nil, nil
	}

	symdat, err := symtab.Data()
	if err != nil {
	return nil, err
	}
	pclndat, err := pclntab.Data()
	if err != nil {
	return nil, err
	}

	pcln := gosym.NewLineTable(pclndat, text.Addr)
	tab, err := gosym.NewTable(symdat, pcln)
	if err != nil {
	return nil, err
	}

	return tab, nil
	}

	// NewProcessElf constructs a new remote process around a traced
	// process and the process' ELF object.
	func NewProcessElf(tproc proc.Process, f elf.File) (Process, os.Error) {
	syms, err := elfGoSyms(f)
	if err != nil {
	return nil, err
	}
	if syms == nil {
	return nil, FormatError("Failed to find symbol table")
	}
	var arch Arch
	switch f.Machine {
	case elf.EM_X86_64:
	arch = Amd64
	default:
	return nil, UnknownArchitecture(f.Machine)
	}
	return NewProcess(tproc, arch, syms)
	}

	// bootstrap constructs the runtime structure of a remote process.
	func (p *Process) bootstrap() {
	// Manually construct runtime types
	p.runtime.String = newManualType(eval.TypeOfNative(rt1String{}), p.Arch)
	p.runtime.Slice = newManualType(eval.TypeOfNative(rt1Slice{}), p.Arch)
	p.runtime.Eface = newManualType(eval.TypeOfNative(rt1Eface{}), p.Arch)

	p.runtime.Type = newManualType(eval.TypeOfNative(rt1Type{}), p.Arch)
	p.runtime.CommonType = newManualType(eval.TypeOfNative(rt1CommonType{}), p.Arch)
	p.runtime.UncommonType = newManualType(eval.TypeOfNative(rt1UncommonType{}), p.Arch)
	p.runtime.StructField = newManualType(eval.TypeOfNative(rt1StructField{}), p.Arch)
	p.runtime.StructType = newManualType(eval.TypeOfNative(rt1StructType{}), p.Arch)
	p.runtime.PtrType = newManualType(eval.TypeOfNative(rt1PtrType{}), p.Arch)
	p.runtime.ArrayType = newManualType(eval.TypeOfNative(rt1ArrayType{}), p.Arch)
	p.runtime.SliceType = newManualType(eval.TypeOfNative(rt1SliceType{}), p.Arch)

	p.runtime.Stktop = newManualType(eval.TypeOfNative(rt1Stktop{}), p.Arch)
	p.runtime.Gobuf = newManualType(eval.TypeOfNative(rt1Gobuf{}), p.Arch)
	p.runtime.G = newManualType(eval.TypeOfNative(rt1G{}), p.Arch)

	// Get addresses of type.*runtime.XType for discrimination.
	rtv := reflect.Indirect(reflect.ValueOf(&p.runtime))
	rtvt := rtv.Type()
	for i := 0; i < rtv.NumField(); i++ {
	n := rtvt.Field(i).Name
	if n[0] != 'P' \|\| n[1] < 'A' \|\| n[1] > 'Z' {
	continue
	}
	sym := p.syms.LookupSym("type.*runtime." + n[1:])
	if sym == nil {
	continue
	}
	rtv.Field(i).SetUint(sym.Value)
	}

	// Get runtime field indexes
	fillRuntimeIndexes(&p.runtime, &p.f)

	// Fill G status
	p.runtime.runtimeGStatus = rt1GStatus

	// Get globals
	p.sys.lessstack = p.syms.LookupFunc("sys.lessstack")
	p.sys.goexit = p.syms.LookupFunc("goexit")
	p.sys.newproc = p.syms.LookupFunc("sys.newproc")
	p.sys.deferproc = p.syms.LookupFunc("sys.deferproc")
	p.sys.newprocreadylocked = p.syms.LookupFunc("newprocreadylocked")
	if allg := p.syms.LookupSym("allg"); allg != nil {
	p.sys.allg = remotePtr{remote{proc.Word(allg.Value), p}, p.runtime.G}
	}
	if g0 := p.syms.LookupSym("g0"); g0 != nil {
	p.sys.g0 = p.runtime.G.mk(remote{proc.Word(g0.Value), p}).(remoteStruct)
	}
	}

	func (p *Process) selectSomeGoroutine() {
	// Once we have friendly goroutine ID's, there might be a more
	// reasonable behavior for this.
	p.curGoroutine = nil
	for _, g := range p.goroutines {
	if !g.isG0() && g.frame != nil {
	p.curGoroutine = g
	return
	}
	}
	}

	/*
	* Process memory
	*/

	func (p *Process) someStoppedOSThread() proc.Thread {
	if p.threadCache != nil {
	if _, err := p.threadCache.Stopped(); err == nil {
	return p.threadCache
	}
	}

	for _, t := range p.proc.Threads() {
	if _, err := t.Stopped(); err == nil {
	p.threadCache = t
	return t
	}
	}
	return nil
	}

	func (p *Process) Peek(addr proc.Word, out []byte) (int, os.Error) {
	thr := p.someStoppedOSThread()
	if thr == nil {
	return 0, ProcessNotStopped{}
	}
	return thr.Peek(addr, out)
	}

	func (p *Process) Poke(addr proc.Word, b []byte) (int, os.Error) {
	thr := p.someStoppedOSThread()
	if thr == nil {
	return 0, ProcessNotStopped{}
	}
	return thr.Poke(addr, b)
	}

	func (p *Process) peekUintptr(a aborter, addr proc.Word) proc.Word {
	return proc.Word(mkUintptr(remote{addr, p}).(remoteUint).aGet(a))
	}

	/*
	* Events
	*/

	// OnBreakpoint returns the hook that is run when the program reaches
	// the given program counter.
	func (p *Process) OnBreakpoint(pc proc.Word) EventHook {
	if bp, ok := p.breakpointHooks[pc]; ok {
	return bp
	}
	// The breakpoint will register itself when a handler is added
	return &breakpointHook{commonHook{nil, 0}, p, pc}
	}

	// OnGoroutineCreate returns the hook that is run when a goroutine is created.
	func (p *Process) OnGoroutineCreate() EventHook {
	return p.goroutineCreateHook
	}

	// OnGoroutineExit returns the hook that is run when a goroutine exits.
	func (p *Process) OnGoroutineExit() EventHook { return p.goroutineExitHook }

	// osThreadToGoroutine looks up the goroutine running on an OS thread.
	func (p Process) osThreadToGoroutine(t proc.Thread) (Goroutine, os.Error) {
	regs, err := t.Regs()
	if err != nil {
	return nil, err
	}
	g := p.G(regs)
	gt, ok := p.goroutines[g]
	if !ok {
	return nil, UnknownGoroutine{t, g}
	}
	return gt, nil
	}

	// causesToEvents translates the stop causes of the underlying process
	// into an event queue.
	func (p *Process) causesToEvents() ([]Event, os.Error) {
	// Count causes we're interested in
	nev := 0
	for _, t := range p.proc.Threads() {
	if c, err := t.Stopped(); err == nil {
	switch c := c.(type) {
	case proc.Breakpoint:
	nev++
	case proc.Signal:
	// TODO(austin)
	//nev++;
	}
	}
	}

	// Translate causes to events
	events := make([]Event, nev)
	i := 0
	for _, t := range p.proc.Threads() {
	if c, err := t.Stopped(); err == nil {
	switch c := c.(type) {
	case proc.Breakpoint:
	gt, err := p.osThreadToGoroutine(t)
	if err != nil {
	return nil, err
	}
	events[i] = &Breakpoint{commonEvent{p, gt}, t, proc.Word(c)}
	i++
	case proc.Signal:
	// TODO(austin)
	}
	}
	}

	return events, nil
	}

	// postEvent appends an event to the posted queue. These events will
	// be processed before any currently pending events.
	func (p *Process) postEvent(ev Event) {
	p.posted = append(p.posted, ev)
	}

	// processEvents processes events in the event queue until no events
	// remain, a handler returns EAStop, or a handler returns an error.
	// It returns either EAStop or EAContinue and possibly an error.
	func (p *Process) processEvents() (EventAction, os.Error) {
	var ev Event
	for len(p.posted) > 0 {
	ev, p.posted = p.posted[0], p.posted[1:]
	action, err := p.processEvent(ev)
	if action == EAStop {
	return action, err
	}
	}

	for len(p.pending) > 0 {
	ev, p.pending = p.pending[0], p.pending[1:]
	action, err := p.processEvent(ev)
	if action == EAStop {
	return action, err
	}
	}

	return EAContinue, nil
	}

	// processEvent processes a single event, without manipulating the
	// event queues. It returns either EAStop or EAContinue and possibly
	// an error.
	func (p *Process) processEvent(ev Event) (EventAction, os.Error) {
	p.event = ev

	var action EventAction
	var err os.Error
	switch ev := p.event.(type) {
	case *Breakpoint:
	hook, ok := p.breakpointHooks[ev.pc]
	if !ok {
	break
	}
	p.curGoroutine = ev.Goroutine()
	action, err = hook.handle(ev)

	case *GoroutineCreate:
	p.curGoroutine = ev.Goroutine()
	action, err = p.goroutineCreateHook.handle(ev)

	case *GoroutineExit:
	action, err = p.goroutineExitHook.handle(ev)

	default:
	log.Panicf("Unknown event type %T in queue", p.event)
	}

	if err != nil {
	return EAStop, err
	} else if action == EAStop {
	return EAStop, nil
	}
	return EAContinue, nil
	}

	// Event returns the last event that caused the process to stop. This
	// may return nil if the process has never been stopped by an event.
	//
	// TODO(austin) Return nil if the user calls p.Stop()?
	func (p *Process) Event() Event { return p.event }

	/*
	* Process control
	*/

	// TODO(austin) Cont, WaitStop, and Stop. Need to figure out how
	// event handling works with these. Originally I did it only in
	// WaitStop, but if you Cont and there are pending events, then you
	// have to not actually continue and wait until a WaitStop to process
	// them, even if the event handlers will tell you to continue. We
	// could handle them in both Cont and WaitStop to avoid this problem,
	// but it's still weird if an event happens after the Cont and before
	// the WaitStop that the handlers say to continue from. Or we could
	// handle them on a separate thread. Then obviously you get weird
	// asynchronous things, like prints while the user it typing a command,
	// but that's not necessarily a bad thing.

	// ContWait resumes process execution and waits for an event to occur
	// that stops the process.
	func (p *Process) ContWait() os.Error {
	for {
	a, err := p.processEvents()
	if err != nil {
	return err
	} else if a == EAStop {
	break
	}
	err = p.proc.Continue()
	if err != nil {
	return err
	}
	err = p.proc.WaitStop()
	if err != nil {
	return err
	}
	for _, g := range p.goroutines {
	g.resetFrame()
	}
	p.pending, err = p.causesToEvents()
	if err != nil {
	return err
	}
	}
	return nil
	}

	// Out selects the caller frame of the current frame.
	func (p *Process) Out() os.Error {
	if p.curGoroutine == nil {
	return NoCurrentGoroutine{}
	}
	return p.curGoroutine.Out()
	}

	// In selects the frame called by the current frame.
	func (p *Process) In() os.Error {
	if p.curGoroutine == nil {
	return NoCurrentGoroutine{}
	}
	return p.curGoroutine.In()
	}