--- /dev/null
+// 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 (
+ "fmt";
+ "os";
+ "ptrace";
+)
+
+/*
+ * Hooks and events
+ */
+
+// An EventHandler is a function that takes an event and returns a
+// response to that event and possibly an error. If an event handler
+// returns an error, the process stops and no other handlers for that
+// event are executed.
+type EventHandler func(e Event) (EventAction, os.Error)
+
+// An EventAction is an event handler's response to an event. If all
+// of an event's handlers execute without returning errors, their
+// results are combined as follows: If any handler returned
+// EAContinue, then the process resumes (without returning from
+// WaitStop); otherwise, if any handler returned EAStop, the process
+// remains stopped; otherwise, if all handlers returned EADefault, the
+// process resumes. A handler may return EARemoveSelf bit-wise or'd
+// with any other action to indicate that the handler should be
+// removed from the hook.
+type EventAction int
+
+const (
+ EARemoveSelf EventAction = 0x100;
+ EADefault EventAction = iota;
+ EAStop;
+ EAContinue;
+)
+
+// A EventHook allows event handlers to be added and removed.
+type EventHook interface {
+ AddHandler(EventHandler);
+ RemoveHandler(EventHandler);
+ NumHandler() int;
+ handle(e Event) (EventAction, os.Error);
+ String() string;
+}
+
+// EventHook is almost, but not quite, suitable for user-defined
+// events. If we want user-defined events, make EventHook a struct,
+// special-case adding and removing handlers in breakpoint hooks, and
+// provide a public interface for posting events to hooks.
+
+type Event interface {
+ Process() *Process;
+ Thread() *Thread;
+ String() string;
+}
+
+type commonHook struct {
+ // Head of handler chain
+ head *handler;
+ // Number of non-internal handlers
+ len int;
+}
+
+type handler struct {
+ eh EventHandler;
+ // True if this handler must be run before user-defined
+ // handlers in order to ensure correctness.
+ internal bool;
+ // True if this handler has been removed from the chain.
+ removed bool;
+ next *handler;
+}
+
+func (h *commonHook) AddHandler(eh EventHandler) {
+ h.addHandler(eh, false);
+}
+
+func (h *commonHook) addHandler(eh EventHandler, internal bool) {
+ // Ensure uniqueness of handlers
+ h.RemoveHandler(eh);
+
+ if !internal {
+ h.len++;
+ }
+ // Add internal handlers to the beginning
+ if internal || h.head == nil {
+ h.head = &handler{eh, internal, false, h.head};
+ return;
+ }
+ // Add handler after internal handlers
+ // TODO(austin) This should probably go on the end instead
+ prev := h.head;
+ for prev.next != nil && prev.internal {
+ prev = prev.next;
+ }
+ prev.next = &handler{eh, internal, false, prev.next};
+}
+
+func (h *commonHook) RemoveHandler(eh EventHandler) {
+ plink := &h.head;
+ for l := *plink; l != nil; plink, l = &l.next, l.next {
+ if l.eh == eh {
+ if !l.internal {
+ h.len--;
+ }
+ l.removed = true;
+ *plink = l.next;
+ break;
+ }
+ }
+}
+
+func (h *commonHook) NumHandler() int {
+ return h.len;
+}
+
+func (h *commonHook) handle(e Event) (EventAction, os.Error) {
+ action := EADefault;
+ plink := &h.head;
+ for l := *plink; l != nil; plink, l = &l.next, l.next {
+ if l.removed {
+ continue;
+ }
+ a, err := l.eh(e);
+ if a & EARemoveSelf == EARemoveSelf {
+ if !l.internal {
+ h.len--;
+ }
+ l.removed = true;
+ *plink = l.next;
+ a &^= EARemoveSelf;
+ }
+ if err != nil {
+ return EAStop, err;
+ }
+ if a > action {
+ action = a;
+ }
+ }
+ return action, nil;
+}
+
+type commonEvent struct {
+ // The process of this event
+ p *Process;
+ // The thread of this event.
+ t *Thread;
+}
+
+func (e *commonEvent) Process() *Process {
+ return e.p;
+}
+
+func (e *commonEvent) Thread() *Thread {
+ return e.t;
+}
+
+/*
+ * Standard event handlers
+ */
+
+// EventPrint is a standard event handler that prints events as they
+// occur. It will not cause the process to stop.
+func EventPrint(ev Event) (EventAction, os.Error) {
+ // TODO(austin) Include process name here?
+ fmt.Fprintf(os.Stderr, "*** %v\n", ev.String());
+ return EADefault, nil;
+}
+
+// EventStop is a standard event handler that causes the process to stop.
+func EventStop(ev Event) (EventAction, os.Error) {
+ return EAStop, nil;
+}
+
+/*
+ * Breakpoints
+ */
+
+type breakpointHook struct {
+ commonHook;
+ p *Process;
+ pc ptrace.Word;
+}
+
+// A Breakpoint event occurs when a process reaches a particular
+// program counter. When this event is handled, the current thread
+// will be the thread that reached the program counter.
+type Breakpoint struct {
+ commonEvent;
+ osThread ptrace.Thread;
+ pc ptrace.Word;
+}
+
+func (h *breakpointHook) AddHandler(eh EventHandler) {
+ h.addHandler(eh, false);
+}
+
+func (h *breakpointHook) addHandler(eh EventHandler, internal bool) {
+ // We register breakpoint events lazily to avoid holding
+ // references to breakpoints without handlers. Be sure to use
+ // the "canonical" breakpoint if there is one.
+ if cur, ok := h.p.breakpointHooks[h.pc]; ok {
+ h = cur;
+ }
+ oldhead := h.head;
+ h.commonHook.addHandler(eh, internal);
+ if oldhead == nil && h.head != nil {
+ h.p.proc.AddBreakpoint(h.pc);
+ h.p.breakpointHooks[h.pc] = h;
+ }
+}
+
+func (h *breakpointHook) RemoveHandler(eh EventHandler) {
+ oldhead := h.head;
+ h.commonHook.RemoveHandler(eh);
+ if oldhead != nil && h.head == nil {
+ h.p.proc.RemoveBreakpoint(h.pc);
+ h.p.breakpointHooks[h.pc] = nil, false;
+ }
+}
+
+func (h *breakpointHook) String() string {
+ // TODO(austin) Include process name?
+ // TODO(austin) Use line:pc or at least sym+%#x
+ return fmt.Sprintf("breakpoint at %#x", h.pc);
+}
+
+func (b *Breakpoint) PC() ptrace.Word {
+ return b.pc;
+}
+
+func (b *Breakpoint) String() string {
+ // TODO(austin) Include process name and thread
+ // TODO(austin) Use line:pc or at least sym+%#x
+ return fmt.Sprintf("breakpoint at %#x", b.pc);
+}
+
+/*
+ * Thread create/exit
+ */
+
+type threadCreateHook struct {
+ commonHook;
+}
+
+func (h *threadCreateHook) String() string {
+ return "thread create";
+}
+
+// A ThreadCreate event occurs when a process creates a new Go thread.
+// When this event is handled, the current thread will be the newly
+// created thread.
+type ThreadCreate struct {
+ commonEvent;
+ parent *Thread;
+}
+
+// Parent returns the thread that created this thread. May be nil if
+// this event is the creation of the first thread.
+func (e *ThreadCreate) Parent() *Thread {
+ return e.parent;
+}
+
+func (e *ThreadCreate) String() string {
+ // TODO(austin) Include process name
+ if e.parent == nil {
+ return fmt.Sprintf("%v created", e.t);
+ }
+ return fmt.Sprintf("%v created by %v", e.t, e.parent);
+}
+
+type threadExitHook struct {
+ commonHook;
+}
+
+func (h *threadExitHook) String() string {
+ return "thread exit";
+}
+
+// A ThreadExit event occurs when a Go thread exits.
+type ThreadExit struct {
+ commonEvent;
+}
+
+func (e *ThreadExit) String() string {
+ // TODO(austin) Include process name
+ //return fmt.Sprintf("%v exited", e.t);
+ // For debugging purposes
+ return fmt.Sprintf("thread %#x exited", e.t.g.addr().base);
+}
import (
"eval";
+ "fmt";
+ "log";
+ "os";
"ptrace";
"reflect";
- "os";
"sym";
)
return "process not stopped";
}
+// An UnknownThread error is an internal error representing an
+// unrecognized G structure pointer.
+type UnknownThread struct {
+ OSThread ptrace.Thread;
+ GoThread ptrace.Word;
+}
+
+func (e UnknownThread) String() string {
+ return fmt.Sprintf("internal error: unknown thread (G %#x)", e.GoThread);
+}
+
+// A NoCurrentThread error occurs when no thread is currently selected
+// in a process (or when there are no threads in a process).
+type NoCurrentThread struct {}
+
+func (e NoCurrentThread) String() string {
+ return "no current thread";
+}
+
// A Process represents a remote attached process.
type Process struct {
Arch;
- ptrace.Process;
+ proc ptrace.Process;
// The symbol table of this process
syms *sym.GoSymTable;
- // Current frame, or nil if the current thread is not stopped
- frame *Frame;
-
// A possibly-stopped OS thread, or nil
threadCache ptrace.Thread;
// Globals from the sys package (or from no package)
sys struct {
- lessstack, goexit, newproc, deferproc *sym.TextSym;
+ lessstack, goexit, newproc, deferproc, newprocreadylocked *sym.TextSym;
+ allg remotePtr;
+ g0 remoteStruct;
};
+
+ // Event queue
+ posted []Event;
+ pending []Event;
+ event Event;
+
+ // Event hooks
+ breakpointHooks map[ptrace.Word] *breakpointHook;
+ threadCreateHook *threadCreateHook;
+ threadExitHook *threadExitHook;
+
+ // Current thread, or nil if there are no threads
+ curThread *Thread;
+
+ // Threads by the address of their G structure
+ threads map[ptrace.Word] *Thread;
}
+/*
+ * Process creation
+ */
+
// NewProcess constructs a new remote process around a ptrace'd
// process, an architecture, and a symbol table.
-func NewProcess(proc ptrace.Process, arch Arch, syms *sym.GoSymTable) *Process {
+func NewProcess(proc ptrace.Process, arch Arch, syms *sym.GoSymTable) (*Process, os.Error) {
p := &Process{
Arch: arch,
- Process: proc,
+ proc: proc,
syms: syms,
types: make(map[ptrace.Word] *remoteType),
+ breakpointHooks: make(map[ptrace.Word] *breakpointHook),
+ threadCreateHook: new(threadCreateHook),
+ threadExitHook: new(threadExitHook),
+ threads: make(map[ptrace.Word] *Thread),
};
- // TODO(austin) Set p.frame if proc is stopped
-
+ // Fill in remote runtime
p.bootstrap();
- return p;
+
+ 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 threads
+ p.threads[p.sys.g0.addr().base] = &Thread{p.sys.g0, nil, false};
+ g := p.sys.allg.Get();
+ for g != nil {
+ gs := g.(remoteStruct);
+ fmt.Printf("*** Found thread at %#x\n", gs.addr().base);
+ p.threads[gs.addr().base] = &Thread{gs, nil, false};
+ g = gs.Field(p.f.G.Alllink).(remotePtr).Get();
+ }
+ p.selectSomeThread();
+
+ // Create internal breakpoints to catch new and exited threads
+ p.OnBreakpoint(ptrace.Word(p.sys.newprocreadylocked.Entry())).(*breakpointHook).addHandler(readylockedBP, true);
+ p.OnBreakpoint(ptrace.Word(p.sys.goexit.Entry())).(*breakpointHook).addHandler(goexitBP, true);
+
+ return p, nil;
}
// NewProcessElf constructs a new remote process around a ptrace'd
default:
return nil, UnknownArchitecture(elf.Machine);
}
- return NewProcess(proc, arch, syms), nil;
+ return NewProcess(proc, arch, syms);
}
// bootstrap constructs the runtime structure of a remote process.
p.sys.goexit = globalFn("goexit");
p.sys.newproc = globalFn("sys·newproc");
p.sys.deferproc = globalFn("sys·deferproc");
+ p.sys.newprocreadylocked = globalFn("newprocreadylocked");
+ if allg := p.syms.SymFromName("allg"); allg != nil {
+ p.sys.allg = remotePtr{remote{ptrace.Word(allg.Common().Value), p}, p.runtime.G};
+ }
+ if g0 := p.syms.SymFromName("g0"); g0 != nil {
+ p.sys.g0 = p.runtime.G.mk(remote{ptrace.Word(g0.Common().Value), p}).(remoteStruct);
+ }
+}
+
+func (p *Process) selectSomeThread() {
+ // Once we have friendly thread ID's, there might be a more
+ // reasonable behavior for this.
+ p.curThread = nil;
+ for _, t := range p.threads {
+ if !t.isG0() {
+ p.curThread = t;
+ return;
+ }
+ }
}
-func (p *Process) someStoppedThread() ptrace.Thread {
+/*
+ * Process memory
+ */
+
+func (p *Process) someStoppedOSThread() ptrace.Thread {
if p.threadCache != nil {
if _, err := p.threadCache.Stopped(); err == nil {
return p.threadCache;
}
}
- for _, t := range p.Threads() {
+ for _, t := range p.proc.Threads() {
if _, err := t.Stopped(); err == nil {
p.threadCache = t;
return t;
}
func (p *Process) Peek(addr ptrace.Word, out []byte) (int, os.Error) {
- thr := p.someStoppedThread();
+ thr := p.someStoppedOSThread();
if thr == nil {
return 0, ProcessNotStopped{};
}
}
func (p *Process) Poke(addr ptrace.Word, b []byte) (int, os.Error) {
- thr := p.someStoppedThread();
+ thr := p.someStoppedOSThread();
if thr == nil {
return 0, ProcessNotStopped{};
}
func (p *Process) peekUintptr(addr ptrace.Word) ptrace.Word {
return ptrace.Word(mkUintptr(remote{addr, p}).(remoteUint).Get());
}
+
+/*
+ * Events
+ */
+
+// OnBreakpoint returns the hook that is run when the program reaches
+// the given program counter.
+func (p *Process) OnBreakpoint(pc ptrace.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};
+}
+
+// OnThreadCreate returns the hook that is run when a Go thread is created.
+func (p *Process) OnThreadCreate() EventHook {
+ return p.threadCreateHook;
+}
+
+// OnThreadExit returns the hook
+func (p *Process) OnThreadExit() EventHook {
+ return p.threadExitHook;
+}
+
+// osThreadToThread looks up the Go thread running on an OS thread.
+func (p *Process) osThreadToThread(t ptrace.Thread) (*Thread, os.Error) {
+ regs, err := t.Regs();
+ if err != nil {
+ return nil, err;
+ }
+ g := p.G(regs);
+ gt, ok := p.threads[g];
+ if !ok {
+ return nil, UnknownThread{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 ptrace.Breakpoint:
+ nev++;
+ case ptrace.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 ptrace.Breakpoint:
+ gt, err := p.osThreadToThread(t);
+ if err != nil {
+ return nil, err;
+ }
+ events[i] = &Breakpoint{commonEvent{p, gt}, t, ptrace.Word(c)};
+ i++;
+ case ptrace.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) {
+ n := len(p.posted);
+ m := n*2;
+ if m == 0 {
+ m = 4;
+ }
+ posted := make([]Event, n+1, m);
+ for i, p := range p.posted {
+ posted[i] = p;
+ }
+ posted[n] = ev;
+ p.posted = posted;
+}
+
+// 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:len(p.posted)];
+ 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:len(p.pending)];
+ 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.curThread = ev.Thread();
+ action, err = hook.handle(ev);
+
+ case *ThreadCreate:
+ p.curThread = ev.Thread();
+ action, err = p.threadCreateHook.handle(ev);
+
+ case *ThreadExit:
+ action, err = p.threadExitHook.handle(ev);
+
+ default:
+ log.Crashf("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
+// asynchrony 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 _, t := range p.threads {
+ t.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.curThread == nil {
+ return NoCurrentThread{};
+ }
+ return p.curThread.Out();
+}
+
+// In selects the frame called by the current frame.
+func (p *Process) In() os.Error {
+ if p.curThread == nil {
+ return NoCurrentThread{};
+ }
+ return p.curThread.In();
+}
--- /dev/null
+// 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 (
+ "fmt";
+ "os";
+ "ptrace";
+)
+
+// A Thread represents a Go thread.
+type Thread struct {
+ g remoteStruct;
+ frame *Frame;
+ dead bool;
+}
+
+func (t *Thread) String() string {
+ if t.dead {
+ return "<dead thread>";
+ }
+ // TODO(austin) Give threads friendly ID's
+ return fmt.Sprintf("thread %#x", t.g.addr().base);
+}
+
+// isG0 returns true if this thread if the internal idle thread
+func (t *Thread) isG0() bool {
+ return t.g.addr().base == t.g.r.p.sys.g0.addr().base;
+}
+
+func (t *Thread) resetFrame() {
+ // TODO(austin) NewFrame can abort
+ // TODO(austin) Reuse any live part of the current frame stack
+ // so existing references to Frame's keep working.
+ t.frame = NewFrame(t.g);
+}
+
+// Out selects the caller frame of the current frame.
+func (t *Thread) Out() os.Error {
+ // TODO(austin) Outer can abort
+ f := t.frame.Outer();
+ if f != nil {
+ t.frame = f;
+ }
+ return nil;
+}
+
+// In selects the frame called by the current frame.
+func (t *Thread) In() os.Error {
+ f := t.frame.Inner();
+ if f != nil {
+ t.frame = f;
+ }
+ return nil;
+}
+
+func readylockedBP(ev Event) (EventAction, os.Error) {
+ b := ev.(*Breakpoint);
+ p := b.Process();
+
+ // The new g is the only argument to this function, so the
+ // stack will have the return address, then the G*.
+ regs, err := b.osThread.Regs();
+ if err != nil {
+ return EAStop, err;
+ }
+ sp := regs.SP();
+ addr := sp + ptrace.Word(p.PtrSize());
+ arg := remotePtr{remote{addr, p}, p.runtime.G};
+ g := arg.Get();
+ if g == nil {
+ return EAStop, UnknownThread{b.osThread, 0};
+ }
+ gs := g.(remoteStruct);
+ t := &Thread{gs, nil, false};
+ p.threads[gs.addr().base] = t;
+
+ // Enqueue thread creation event
+ parent := b.Thread();
+ if parent.isG0() {
+ parent = nil;
+ }
+ p.postEvent(&ThreadCreate{commonEvent{p, t}, parent});
+
+ // If we don't have any thread selected, select this one
+ if p.curThread == nil {
+ p.curThread = t;
+ }
+
+ return EADefault, nil;
+}
+
+func goexitBP(ev Event) (EventAction, os.Error) {
+ b := ev.(*Breakpoint);
+ p := b.Process();
+
+ t := b.Thread();
+ t.dead = true;
+
+ addr := t.g.addr().base;
+ p.threads[addr] = nil, false;
+
+ // Enqueue thread exit event
+ p.postEvent(&ThreadExit{commonEvent{p, t}});
+
+ // If we just exited our selected thread, selected another
+ if p.curThread == t {
+ p.selectSomeThread();
+ }
+
+ return EADefault, nil;
+}