1 files changed, 373 insertions, 0 deletions
diff --git a/libgo/go/exp/ogle/cmd.go b/libgo/go/exp/ogle/cmd.go
new file mode 100644
index 000000000..4f67032d0
--- /dev/null
+++ b/libgo/go/exp/ogle/cmd.go
@@ -0,0 +1,373 @@
+// 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.
+
+// Ogle is the beginning of a debugger for Go.
+package ogle
+
+import (
+	"bufio"
+	"debug/elf"
+	"debug/proc"
+	"exp/eval"
+	"fmt"
+	"go/scanner"
+	"go/token"
+	"os"
+	"strconv"
+	"strings"
+)
+
+var fset = token.NewFileSet()
+var world *eval.World
+var curProc *Process
+
+func Main() {
+	world = eval.NewWorld()
+	defineFuncs()
+	r := bufio.NewReader(os.Stdin)
+	for {
+		print("; ")
+		line, err := r.ReadSlice('\n')
+		if err != nil {
+			break
+		}
+
+		// Try line as a command
+		cmd, rest := getCmd(line)
+		if cmd != nil {
+			err := cmd.handler(rest)
+			if err != nil {
+				scanner.PrintError(os.Stderr, err)
+			}
+			continue
+		}
+
+		// Try line as code
+		code, err := world.Compile(fset, string(line))
+		if err != nil {
+			scanner.PrintError(os.Stderr, err)
+			continue
+		}
+		v, err := code.Run()
+		if err != nil {
+			fmt.Fprintf(os.Stderr, err.String())
+			continue
+		}
+		if v != nil {
+			println(v.String())
+		}
+	}
+}
+
+// newScanner creates a new scanner that scans that given input bytes.
+func newScanner(input []byte) (*scanner.Scanner, *scanner.ErrorVector) {
+	sc := new(scanner.Scanner)
+	ev := new(scanner.ErrorVector)
+	file := fset.AddFile("input", fset.Base(), len(input))
+	sc.Init(file, input, ev, 0)
+	return sc, ev
+}
+
+/*
+ * Commands
+ */
+
+// A UsageError occurs when a command is called with illegal arguments.
+type UsageError string
+
+func (e UsageError) String() string { return string(e) }
+
+// A cmd represents a single command with a handler.
+type cmd struct {
+	cmd     string
+	handler func([]byte) os.Error
+}
+
+var cmds = []cmd{
+	{"load", cmdLoad},
+	{"bt", cmdBt},
+}
+
+// getCmd attempts to parse an input line as a registered command.  If
+// successful, it returns the command and the bytes remaining after
+// the command, which should be passed to the command.
+func getCmd(line []byte) (*cmd, []byte) {
+	sc, _ := newScanner(line)
+	pos, tok, lit := sc.Scan()
+	if sc.ErrorCount != 0 || tok != token.IDENT {
+		return nil, nil
+	}
+
+	slit := string(lit)
+	for i := range cmds {
+		if cmds[i].cmd == slit {
+			return &cmds[i], line[fset.Position(pos).Offset+len(lit):]
+		}
+	}
+	return nil, nil
+}
+
+// cmdLoad starts or attaches to a process.  Its form is similar to
+// import:
+//
+//  load [sym] "path" [;]
+//
+// sym specifies the name to give to the process.  If not given, the
+// name is derived from the path of the process.  If ".", then the
+// packages from the remote process are defined into the current
+// namespace.  If given, this symbol is defined as a package
+// containing the process' packages.
+//
+// path gives the path of the process to start or attach to.  If it is
+// "pid:<num>", then attach to the given PID.  Otherwise, treat it as
+// a file path and space-separated arguments and start a new process.
+//
+// load always sets the current process to the loaded process.
+func cmdLoad(args []byte) os.Error {
+	ident, path, err := parseLoad(args)
+	if err != nil {
+		return err
+	}
+	if curProc != nil {
+		return UsageError("multiple processes not implemented")
+	}
+	if ident != "." {
+		return UsageError("process identifiers not implemented")
+	}
+
+	// Parse argument and start or attach to process
+	var fname string
+	var tproc proc.Process
+	if len(path) >= 4 && path[0:4] == "pid:" {
+		pid, err := strconv.Atoi(path[4:])
+		if err != nil {
+			return err
+		}
+		fname, err = os.Readlink(fmt.Sprintf("/proc/%d/exe", pid))
+		if err != nil {
+			return err
+		}
+		tproc, err = proc.Attach(pid)
+		if err != nil {
+			return err
+		}
+		println("Attached to", pid)
+	} else {
+		parts := strings.Split(path, " ", -1)
+		if len(parts) == 0 {
+			fname = ""
+		} else {
+			fname = parts[0]
+		}
+		tproc, err = proc.ForkExec(fname, parts, os.Environ(), "", []*os.File{os.Stdin, os.Stdout, os.Stderr})
+		if err != nil {
+			return err
+		}
+		println("Started", path)
+		// TODO(austin) If we fail after this point, kill tproc
+		// before detaching.
+	}
+
+	// Get symbols
+	f, err := os.Open(fname, os.O_RDONLY, 0)
+	if err != nil {
+		tproc.Detach()
+		return err
+	}
+	defer f.Close()
+	elf, err := elf.NewFile(f)
+	if err != nil {
+		tproc.Detach()
+		return err
+	}
+	curProc, err = NewProcessElf(tproc, elf)
+	if err != nil {
+		tproc.Detach()
+		return err
+	}
+
+	// Prepare new process
+	curProc.OnGoroutineCreate().AddHandler(EventPrint)
+	curProc.OnGoroutineExit().AddHandler(EventPrint)
+
+	err = curProc.populateWorld(world)
+	if err != nil {
+		tproc.Detach()
+		return err
+	}
+
+	return nil
+}
+
+func parseLoad(args []byte) (ident string, path string, err os.Error) {
+	err = UsageError("Usage: load [sym] \"path\"")
+	sc, ev := newScanner(args)
+
+	var toks [4]token.Token
+	var lits [4][]byte
+	for i := range toks {
+		_, toks[i], lits[i] = sc.Scan()
+	}
+	if sc.ErrorCount != 0 {
+		err = ev.GetError(scanner.NoMultiples)
+		return
+	}
+
+	i := 0
+	switch toks[i] {
+	case token.PERIOD, token.IDENT:
+		ident = string(lits[i])
+		i++
+	}
+
+	if toks[i] != token.STRING {
+		return
+	}
+	path, uerr := strconv.Unquote(string(lits[i]))
+	if uerr != nil {
+		err = uerr
+		return
+	}
+	i++
+
+	if toks[i] == token.SEMICOLON {
+		i++
+	}
+	if toks[i] != token.EOF {
+		return
+	}
+
+	return ident, path, nil
+}
+
+// cmdBt prints a backtrace for the current goroutine.  It takes no
+// arguments.
+func cmdBt(args []byte) os.Error {
+	err := parseNoArgs(args, "Usage: bt")
+	if err != nil {
+		return err
+	}
+
+	if curProc == nil || curProc.curGoroutine == nil {
+		return NoCurrentGoroutine{}
+	}
+
+	f := curProc.curGoroutine.frame
+	if f == nil {
+		fmt.Println("No frames on stack")
+		return nil
+	}
+
+	for f.Inner() != nil {
+		f = f.Inner()
+	}
+
+	for i := 0; i < 100; i++ {
+		if f == curProc.curGoroutine.frame {
+			fmt.Printf("=> ")
+		} else {
+			fmt.Printf("   ")
+		}
+		fmt.Printf("%8x %v\n", f.pc, f)
+		f, err = f.Outer()
+		if err != nil {
+			return err
+		}
+		if f == nil {
+			return nil
+		}
+	}
+
+	fmt.Println("...")
+	return nil
+}
+
+func parseNoArgs(args []byte, usage string) os.Error {
+	sc, ev := newScanner(args)
+	_, tok, _ := sc.Scan()
+	if sc.ErrorCount != 0 {
+		return ev.GetError(scanner.NoMultiples)
+	}
+	if tok != token.EOF {
+		return UsageError(usage)
+	}
+	return nil
+}
+
+/*
+ * Functions
+ */
+
+// defineFuncs populates world with the built-in functions.
+func defineFuncs() {
+	t, v := eval.FuncFromNativeTyped(fnOut, fnOutSig)
+	world.DefineConst("Out", t, v)
+	t, v = eval.FuncFromNativeTyped(fnContWait, fnContWaitSig)
+	world.DefineConst("ContWait", t, v)
+	t, v = eval.FuncFromNativeTyped(fnBpSet, fnBpSetSig)
+	world.DefineConst("BpSet", t, v)
+}
+
+// printCurFrame prints the current stack frame, as it would appear in
+// a backtrace.
+func printCurFrame() {
+	if curProc == nil || curProc.curGoroutine == nil {
+		return
+	}
+	f := curProc.curGoroutine.frame
+	if f == nil {
+		return
+	}
+	fmt.Printf("=> %8x %v\n", f.pc, f)
+}
+
+// fnOut moves the current frame to the caller of the current frame.
+func fnOutSig() {}
+func fnOut(t *eval.Thread, args []eval.Value, res []eval.Value) {
+	if curProc == nil {
+		t.Abort(NoCurrentGoroutine{})
+	}
+	err := curProc.Out()
+	if err != nil {
+		t.Abort(err)
+	}
+	// TODO(austin) Only in the command form
+	printCurFrame()
+}
+
+// fnContWait continues the current process and waits for a stopping event.
+func fnContWaitSig() {}
+func fnContWait(t *eval.Thread, args []eval.Value, res []eval.Value) {
+	if curProc == nil {
+		t.Abort(NoCurrentGoroutine{})
+	}
+	err := curProc.ContWait()
+	if err != nil {
+		t.Abort(err)
+	}
+	// TODO(austin) Only in the command form
+	ev := curProc.Event()
+	if ev != nil {
+		fmt.Printf("%v\n", ev)
+	}
+	printCurFrame()
+}
+
+// fnBpSet sets a breakpoint at the entry to the named function.
+func fnBpSetSig(string) {}
+func fnBpSet(t *eval.Thread, args []eval.Value, res []eval.Value) {
+	// TODO(austin) This probably shouldn't take a symbol name.
+	// Perhaps it should take an interface that provides PC's.
+	// Functions and instructions can implement that interface and
+	// we can have something to translate file:line pairs.
+	if curProc == nil {
+		t.Abort(NoCurrentGoroutine{})
+	}
+	name := args[0].(eval.StringValue).Get(t)
+	fn := curProc.syms.LookupFunc(name)
+	if fn == nil {
+		t.Abort(UsageError("no such function " + name))
+	}
+	curProc.OnBreakpoint(proc.Word(fn.Entry)).AddHandler(EventStop)
+}