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author | upstream source tree <ports@midipix.org> | 2015-03-15 20:14:05 -0400 |
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committer | upstream source tree <ports@midipix.org> | 2015-03-15 20:14:05 -0400 |
commit | 554fd8c5195424bdbcabf5de30fdc183aba391bd (patch) | |
tree | 976dc5ab7fddf506dadce60ae936f43f58787092 /libgo/go/exp/ogle/cmd.go | |
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Diffstat (limited to 'libgo/go/exp/ogle/cmd.go')
-rw-r--r-- | libgo/go/exp/ogle/cmd.go | 373 |
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) +} |