forked from go-delve/delve
/
proc.go
491 lines (441 loc) · 12.6 KB
/
proc.go
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package proc
import (
"encoding/binary"
"errors"
"fmt"
"go/ast"
"go/token"
"path/filepath"
"strconv"
)
var NotExecutableErr = errors.New("not an executable file")
var NotRecordedErr = errors.New("not a recording")
const UnrecoveredPanic = "unrecovered-panic"
// ProcessExitedError indicates that the process has exited and contains both
// process id and exit status.
type ProcessExitedError struct {
Pid int
Status int
}
func (pe ProcessExitedError) Error() string {
return fmt.Sprintf("Process %d has exited with status %d", pe.Pid, pe.Status)
}
// FindFileLocation returns the PC for a given file:line.
// Assumes that `file` is normailzed to lower case and '/' on Windows.
func FindFileLocation(p Process, fileName string, lineno int) (uint64, error) {
pc, fn, err := p.BinInfo().LineToPC(fileName, lineno)
if err != nil {
return 0, err
}
if fn.Entry == pc {
pc, _ = FirstPCAfterPrologue(p, fn, true)
}
return pc, nil
}
// FindFunctionLocation finds address of a function's line
// If firstLine == true is passed FindFunctionLocation will attempt to find the first line of the function
// If lineOffset is passed FindFunctionLocation will return the address of that line
// Pass lineOffset == 0 and firstLine == false if you want the address for the function's entry point
// Note that setting breakpoints at that address will cause surprising behavior:
// https://github.com/derekparker/delve/issues/170
func FindFunctionLocation(p Process, funcName string, firstLine bool, lineOffset int) (uint64, error) {
bi := p.BinInfo()
origfn := bi.LookupFunc[funcName]
if origfn == nil {
return 0, fmt.Errorf("Could not find function %s\n", funcName)
}
if firstLine {
return FirstPCAfterPrologue(p, origfn, false)
} else if lineOffset > 0 {
filename, lineno := origfn.cu.lineInfo.PCToLine(origfn.Entry, origfn.Entry)
breakAddr, _, err := bi.LineToPC(filename, lineno+lineOffset)
return breakAddr, err
}
return origfn.Entry, nil
}
// Next continues execution until the next source line.
func Next(dbp Process) (err error) {
if dbp.Exited() {
return &ProcessExitedError{Pid: dbp.Pid()}
}
if dbp.Breakpoints().HasInternalBreakpoints() {
return fmt.Errorf("next while nexting")
}
if err = next(dbp, false); err != nil {
dbp.ClearInternalBreakpoints()
return
}
return Continue(dbp)
}
// Continue continues execution of the debugged
// process. It will continue until it hits a breakpoint
// or is otherwise stopped.
func Continue(dbp Process) error {
if dbp.Exited() {
return &ProcessExitedError{Pid: dbp.Pid()}
}
dbp.ManualStopRequested()
for {
if dbp.ManualStopRequested() {
return nil
}
trapthread, err := dbp.ContinueOnce()
if err != nil {
return err
}
threads := dbp.ThreadList()
if err := pickCurrentThread(dbp, trapthread, threads); err != nil {
return err
}
curthread := dbp.CurrentThread()
curbp := curthread.Breakpoint()
switch {
case curbp.Breakpoint == nil:
// runtime.Breakpoint or manual stop
if recorded, _ := dbp.Recorded(); onRuntimeBreakpoint(curthread) && !recorded {
// Single-step current thread until we exit runtime.breakpoint and
// runtime.Breakpoint.
// On go < 1.8 it was sufficient to single-step twice on go1.8 a change
// to the compiler requires 4 steps.
for {
if err = curthread.StepInstruction(); err != nil {
return err
}
loc, err := curthread.Location()
if err != nil || loc.Fn == nil || (loc.Fn.Name != "runtime.breakpoint" && loc.Fn.Name != "runtime.Breakpoint") {
break
}
}
}
return conditionErrors(threads)
case curbp.Active && curbp.Internal:
if curbp.Kind == StepBreakpoint {
// See description of proc.(*Process).next for the meaning of StepBreakpoints
if err := conditionErrors(threads); err != nil {
return err
}
regs, err := curthread.Registers(false)
if err != nil {
return err
}
pc := regs.PC()
text, err := disassemble(curthread, regs, dbp.Breakpoints(), dbp.BinInfo(), pc, pc+maxInstructionLength, true)
if err != nil {
return err
}
// here we either set a breakpoint into the destination of the CALL
// instruction or we determined that the called function is hidden,
// either way we need to resume execution
if err = setStepIntoBreakpoint(dbp, text, SameGoroutineCondition(dbp.SelectedGoroutine())); err != nil {
return err
}
} else {
if err := dbp.ClearInternalBreakpoints(); err != nil {
return err
}
return conditionErrors(threads)
}
case curbp.Active:
onNextGoroutine, err := onNextGoroutine(curthread, dbp.Breakpoints())
if err != nil {
return err
}
if onNextGoroutine {
err := dbp.ClearInternalBreakpoints()
if err != nil {
return err
}
}
if curbp.Name == UnrecoveredPanic {
dbp.ClearInternalBreakpoints()
}
return conditionErrors(threads)
default:
// not a manual stop, not on runtime.Breakpoint, not on a breakpoint, just repeat
}
}
}
func conditionErrors(threads []Thread) error {
var condErr error
for _, th := range threads {
if bp := th.Breakpoint(); bp.Breakpoint != nil && bp.CondError != nil {
if condErr == nil {
condErr = bp.CondError
} else {
return fmt.Errorf("multiple errors evaluating conditions")
}
}
}
return condErr
}
// pick a new dbp.currentThread, with the following priority:
// - a thread with onTriggeredInternalBreakpoint() == true
// - a thread with onTriggeredBreakpoint() == true (prioritizing trapthread)
// - trapthread
func pickCurrentThread(dbp Process, trapthread Thread, threads []Thread) error {
for _, th := range threads {
if bp := th.Breakpoint(); bp.Active && bp.Internal {
return dbp.SwitchThread(th.ThreadID())
}
}
if bp := trapthread.Breakpoint(); bp.Active {
return dbp.SwitchThread(trapthread.ThreadID())
}
for _, th := range threads {
if bp := th.Breakpoint(); bp.Active {
return dbp.SwitchThread(th.ThreadID())
}
}
return dbp.SwitchThread(trapthread.ThreadID())
}
// Step will continue until another source line is reached.
// Will step into functions.
func Step(dbp Process) (err error) {
if dbp.Exited() {
return &ProcessExitedError{Pid: dbp.Pid()}
}
if dbp.Breakpoints().HasInternalBreakpoints() {
return fmt.Errorf("next while nexting")
}
if err = next(dbp, true); err != nil {
switch err.(type) {
case ThreadBlockedError: // Noop
default:
dbp.ClearInternalBreakpoints()
return
}
}
return Continue(dbp)
}
// SameGoroutineCondition returns an expression that evaluates to true when
// the current goroutine is g.
func SameGoroutineCondition(g *G) ast.Expr {
if g == nil {
return nil
}
return &ast.BinaryExpr{
Op: token.EQL,
X: &ast.SelectorExpr{
X: &ast.SelectorExpr{
X: &ast.Ident{Name: "runtime"},
Sel: &ast.Ident{Name: "curg"},
},
Sel: &ast.Ident{Name: "goid"},
},
Y: &ast.BasicLit{Kind: token.INT, Value: strconv.Itoa(g.ID)},
}
}
func frameoffCondition(frameoff int64) ast.Expr {
return &ast.BinaryExpr{
Op: token.EQL,
X: &ast.SelectorExpr{
X: &ast.Ident{Name: "runtime"},
Sel: &ast.Ident{Name: "frameoff"},
},
Y: &ast.BasicLit{Kind: token.INT, Value: strconv.FormatInt(frameoff, 10)},
}
}
func andFrameoffCondition(cond ast.Expr, frameoff int64) ast.Expr {
if cond == nil {
return nil
}
return &ast.BinaryExpr{
Op: token.LAND,
X: cond,
Y: frameoffCondition(frameoff),
}
}
// StepOut will continue until the current goroutine exits the
// function currently being executed or a deferred function is executed
func StepOut(dbp Process) error {
if dbp.Exited() {
return &ProcessExitedError{Pid: dbp.Pid()}
}
selg := dbp.SelectedGoroutine()
curthread := dbp.CurrentThread()
topframe, retframe, err := topframe(selg, curthread)
if err != nil {
return err
}
sameGCond := SameGoroutineCondition(selg)
retFrameCond := andFrameoffCondition(sameGCond, retframe.FrameOffset())
var deferpc uint64 = 0
if filepath.Ext(topframe.Current.File) == ".go" {
if selg != nil {
deferPCEntry := selg.DeferPC()
if deferPCEntry != 0 {
_, _, deferfn := dbp.BinInfo().PCToLine(deferPCEntry)
deferpc, err = FirstPCAfterPrologue(dbp, deferfn, false)
if err != nil {
return err
}
}
}
}
if topframe.Ret == 0 && deferpc == 0 {
return errors.New("nothing to stepout to")
}
if deferpc != 0 && deferpc != topframe.Current.PC {
bp, err := dbp.SetBreakpoint(deferpc, NextDeferBreakpoint, sameGCond)
if err != nil {
if _, ok := err.(BreakpointExistsError); !ok {
dbp.ClearInternalBreakpoints()
return err
}
}
if bp != nil {
// For StepOut we do not want to step into the deferred function
// when it's called by runtime.deferreturn so we do not populate
// DeferReturns.
bp.DeferReturns = []uint64{}
}
}
if topframe.Ret != 0 {
_, err := dbp.SetBreakpoint(topframe.Ret, NextBreakpoint, retFrameCond)
if err != nil {
if _, isexists := err.(BreakpointExistsError); !isexists {
dbp.ClearInternalBreakpoints()
return err
}
}
}
if bp := curthread.Breakpoint(); bp.Breakpoint == nil {
curthread.SetCurrentBreakpoint()
}
return Continue(dbp)
}
// If the argument of GoroutinesInfo implements AllGCache GoroutinesInfo
// will use the pointer returned by AllGCache as a cache.
type AllGCache interface {
AllGCache() *[]*G
}
// GoroutinesInfo returns an array of G structures representing the information
// Delve cares about from the internal runtime G structure.
func GoroutinesInfo(dbp Process) ([]*G, error) {
if dbp.Exited() {
return nil, &ProcessExitedError{Pid: dbp.Pid()}
}
if dbp, ok := dbp.(AllGCache); ok {
if allGCache := dbp.AllGCache(); *allGCache != nil {
return *allGCache, nil
}
}
var (
threadg = map[int]*G{}
allg []*G
rdr = dbp.BinInfo().DwarfReader()
)
threads := dbp.ThreadList()
for _, th := range threads {
if th.Blocked() {
continue
}
g, _ := GetG(th)
if g != nil {
threadg[g.ID] = g
}
}
addr, err := rdr.AddrFor("runtime.allglen")
if err != nil {
return nil, err
}
allglenBytes := make([]byte, 8)
_, err = dbp.CurrentThread().ReadMemory(allglenBytes, uintptr(addr))
if err != nil {
return nil, err
}
allglen := binary.LittleEndian.Uint64(allglenBytes)
rdr.Seek(0)
allgentryaddr, err := rdr.AddrFor("runtime.allgs")
if err != nil {
// try old name (pre Go 1.6)
allgentryaddr, err = rdr.AddrFor("runtime.allg")
if err != nil {
return nil, err
}
}
faddr := make([]byte, dbp.BinInfo().Arch.PtrSize())
_, err = dbp.CurrentThread().ReadMemory(faddr, uintptr(allgentryaddr))
if err != nil {
return nil, err
}
allgptr := binary.LittleEndian.Uint64(faddr)
for i := uint64(0); i < allglen; i++ {
gvar, err := newGVariable(dbp.CurrentThread(), uintptr(allgptr+(i*uint64(dbp.BinInfo().Arch.PtrSize()))), true)
if err != nil {
return nil, err
}
g, err := gvar.parseG()
if err != nil {
return nil, err
}
if thg, allocated := threadg[g.ID]; allocated {
loc, err := thg.Thread.Location()
if err != nil {
return nil, err
}
g.Thread = thg.Thread
// Prefer actual thread location information.
g.CurrentLoc = *loc
g.SystemStack = thg.SystemStack
}
if g.Status != Gdead {
allg = append(allg, g)
}
}
if dbp, ok := dbp.(AllGCache); ok {
allGCache := dbp.AllGCache()
*allGCache = allg
}
return allg, nil
}
// FindGoroutine returns a G struct representing the goroutine
// specified by `gid`.
func FindGoroutine(dbp Process, gid int) (*G, error) {
if gid == -1 {
return dbp.SelectedGoroutine(), nil
}
gs, err := GoroutinesInfo(dbp)
if err != nil {
return nil, err
}
for i := range gs {
if gs[i].ID == gid {
return gs[i], nil
}
}
return nil, fmt.Errorf("Unknown goroutine %d", gid)
}
// ConvertEvalScope returns a new EvalScope in the context of the
// specified goroutine ID and stack frame.
func ConvertEvalScope(dbp Process, gid, frame int) (*EvalScope, error) {
if dbp.Exited() {
return nil, &ProcessExitedError{Pid: dbp.Pid()}
}
ct := dbp.CurrentThread()
g, err := FindGoroutine(dbp, gid)
if err != nil {
return nil, err
}
if g == nil {
return ThreadScope(ct)
}
var thread MemoryReadWriter
if g.Thread == nil {
thread = ct
} else {
thread = g.Thread
}
locs, err := g.Stacktrace(frame)
if err != nil {
return nil, err
}
if frame >= len(locs) {
return nil, fmt.Errorf("Frame %d does not exist in goroutine %d", frame, gid)
}
return &EvalScope{locs[frame].Current.PC, locs[frame].Regs, thread, g.variable, dbp.BinInfo(), locs[frame].FrameOffset()}, nil
}
// FrameToScope returns a new EvalScope for this frame
func FrameToScope(p Process, frame Stackframe) *EvalScope {
return &EvalScope{frame.Current.PC, frame.Regs, p.CurrentThread(), nil, p.BinInfo(), frame.FrameOffset()}
}