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bee/vendor/github.com/derekparker/delve/proc/proc_darwin.go
2017-03-26 16:55:28 +02:00

512 lines
12 KiB
Go

package proc
// #include "proc_darwin.h"
// #include "threads_darwin.h"
// #include "exec_darwin.h"
// #include <stdlib.h>
import "C"
import (
"debug/gosym"
"errors"
"fmt"
"os"
"os/exec"
"path/filepath"
"sync"
"unsafe"
"golang.org/x/debug/macho"
"github.com/derekparker/delve/dwarf/frame"
"github.com/derekparker/delve/dwarf/line"
sys "golang.org/x/sys/unix"
)
// OSProcessDetails holds Darwin specific information.
type OSProcessDetails struct {
task C.task_t // mach task for the debugged process.
exceptionPort C.mach_port_t // mach port for receiving mach exceptions.
notificationPort C.mach_port_t // mach port for dead name notification (process exit).
initialized bool
// the main port we use, will return messages from both the
// exception and notification ports.
portSet C.mach_port_t
}
// Launch creates and begins debugging a new process. Uses a
// custom fork/exec process in order to take advantage of
// PT_SIGEXC on Darwin which will turn Unix signals into
// Mach exceptions.
func Launch(cmd []string, wd string) (*Process, error) {
// check that the argument to Launch is an executable file
if fi, staterr := os.Stat(cmd[0]); staterr == nil && (fi.Mode()&0111) == 0 {
return nil, NotExecutableErr
}
argv0Go, err := filepath.Abs(cmd[0])
if err != nil {
return nil, err
}
// Make sure the binary exists.
if filepath.Base(cmd[0]) == cmd[0] {
if _, err := exec.LookPath(cmd[0]); err != nil {
return nil, err
}
}
if _, err := os.Stat(argv0Go); err != nil {
return nil, err
}
argv0 := C.CString(argv0Go)
argvSlice := make([]*C.char, 0, len(cmd)+1)
for _, arg := range cmd {
argvSlice = append(argvSlice, C.CString(arg))
}
// argv array must be null terminated.
argvSlice = append(argvSlice, nil)
dbp := New(0)
var pid int
dbp.execPtraceFunc(func() {
ret := C.fork_exec(argv0, &argvSlice[0], C.int(len(argvSlice)),
C.CString(wd),
&dbp.os.task, &dbp.os.portSet, &dbp.os.exceptionPort,
&dbp.os.notificationPort)
pid = int(ret)
})
if pid <= 0 {
return nil, fmt.Errorf("could not fork/exec")
}
dbp.Pid = pid
for i := range argvSlice {
C.free(unsafe.Pointer(argvSlice[i]))
}
// Initialize enough of the Process state so that we can use resume and
// trapWait to wait until the child process calls execve.
for {
err = dbp.updateThreadListForTask(C.get_task_for_pid(C.int(dbp.Pid)))
if err == nil {
break
}
if err != couldNotGetThreadCount && err != couldNotGetThreadList {
return nil, err
}
}
if err := dbp.resume(); err != nil {
return nil, err
}
dbp.allGCache = nil
for _, th := range dbp.Threads {
th.clearBreakpointState()
}
trapthread, err := dbp.trapWait(-1)
if err != nil {
return nil, err
}
if err := dbp.Halt(); err != nil {
return nil, dbp.exitGuard(err)
}
_, err = dbp.waitForStop()
if err != nil {
return nil, err
}
dbp.os.initialized = true
dbp, err = initializeDebugProcess(dbp, argv0Go, false)
if err != nil {
return nil, err
}
if err := dbp.SwitchThread(trapthread.ID); err != nil {
return nil, err
}
return dbp, err
}
// Attach to an existing process with the given PID.
func Attach(pid int) (*Process, error) {
dbp := New(pid)
kret := C.acquire_mach_task(C.int(pid),
&dbp.os.task, &dbp.os.portSet, &dbp.os.exceptionPort,
&dbp.os.notificationPort)
if kret != C.KERN_SUCCESS {
return nil, fmt.Errorf("could not attach to %d", pid)
}
dbp.os.initialized = true
return initializeDebugProcess(dbp, "", true)
}
// Kill kills the process.
func (dbp *Process) Kill() (err error) {
if dbp.exited {
return nil
}
err = sys.Kill(-dbp.Pid, sys.SIGKILL)
if err != nil {
return errors.New("could not deliver signal: " + err.Error())
}
for port := range dbp.Threads {
if C.thread_resume(C.thread_act_t(port)) != C.KERN_SUCCESS {
return errors.New("could not resume task")
}
}
for {
var task C.task_t
port := C.mach_port_wait(dbp.os.portSet, &task, C.int(0))
if port == dbp.os.notificationPort {
break
}
}
dbp.postExit()
return
}
func (dbp *Process) requestManualStop() (err error) {
var (
task = C.mach_port_t(dbp.os.task)
thread = C.mach_port_t(dbp.CurrentThread.os.threadAct)
exceptionPort = C.mach_port_t(dbp.os.exceptionPort)
)
kret := C.raise_exception(task, thread, exceptionPort, C.EXC_BREAKPOINT)
if kret != C.KERN_SUCCESS {
return fmt.Errorf("could not raise mach exception")
}
return nil
}
var couldNotGetThreadCount = errors.New("could not get thread count")
var couldNotGetThreadList = errors.New("could not get thread list")
func (dbp *Process) updateThreadList() error {
return dbp.updateThreadListForTask(dbp.os.task)
}
func (dbp *Process) updateThreadListForTask(task C.task_t) error {
var (
err error
kret C.kern_return_t
count C.int
list []uint32
)
for {
count = C.thread_count(task)
if count == -1 {
return couldNotGetThreadCount
}
list = make([]uint32, count)
// TODO(dp) might be better to malloc mem in C and then free it here
// instead of getting count above and passing in a slice
kret = C.get_threads(task, unsafe.Pointer(&list[0]), count)
if kret != -2 {
break
}
}
if kret != C.KERN_SUCCESS {
return couldNotGetThreadList
}
for _, thread := range dbp.Threads {
thread.os.exists = false
}
for _, port := range list {
thread, ok := dbp.Threads[int(port)]
if !ok {
thread, err = dbp.addThread(int(port), false)
if err != nil {
return err
}
}
thread.os.exists = true
}
for threadID, thread := range dbp.Threads {
if !thread.os.exists {
delete(dbp.Threads, threadID)
}
}
return nil
}
func (dbp *Process) addThread(port int, attach bool) (*Thread, error) {
if thread, ok := dbp.Threads[port]; ok {
return thread, nil
}
thread := &Thread{
ID: port,
dbp: dbp,
os: new(OSSpecificDetails),
}
dbp.Threads[port] = thread
thread.os.threadAct = C.thread_act_t(port)
if dbp.CurrentThread == nil {
dbp.SwitchThread(thread.ID)
}
return thread, nil
}
func (dbp *Process) parseDebugFrame(exe *macho.File, wg *sync.WaitGroup) {
defer wg.Done()
debugFrameSec := exe.Section("__debug_frame")
debugInfoSec := exe.Section("__debug_info")
if debugFrameSec != nil && debugInfoSec != nil {
debugFrame, err := exe.Section("__debug_frame").Data()
if err != nil {
fmt.Println("could not get __debug_frame section", err)
os.Exit(1)
}
dat, err := debugInfoSec.Data()
if err != nil {
fmt.Println("could not get .debug_info section", err)
os.Exit(1)
}
dbp.frameEntries = frame.Parse(debugFrame, frame.DwarfEndian(dat))
} else {
fmt.Println("could not find __debug_frame section in binary")
os.Exit(1)
}
}
func (dbp *Process) obtainGoSymbols(exe *macho.File, wg *sync.WaitGroup) {
defer wg.Done()
var (
symdat []byte
pclndat []byte
err error
)
if sec := exe.Section("__gosymtab"); sec != nil {
symdat, err = sec.Data()
if err != nil {
fmt.Println("could not get .gosymtab section", err)
os.Exit(1)
}
}
if sec := exe.Section("__gopclntab"); sec != nil {
pclndat, err = sec.Data()
if err != nil {
fmt.Println("could not get .gopclntab section", err)
os.Exit(1)
}
}
pcln := gosym.NewLineTable(pclndat, exe.Section("__text").Addr)
tab, err := gosym.NewTable(symdat, pcln)
if err != nil {
fmt.Println("could not get initialize line table", err)
os.Exit(1)
}
dbp.goSymTable = tab
}
func (dbp *Process) parseDebugLineInfo(exe *macho.File, wg *sync.WaitGroup) {
defer wg.Done()
if sec := exe.Section("__debug_line"); sec != nil {
debugLine, err := exe.Section("__debug_line").Data()
if err != nil {
fmt.Println("could not get __debug_line section", err)
os.Exit(1)
}
dbp.lineInfo = line.Parse(debugLine)
} else {
fmt.Println("could not find __debug_line section in binary")
os.Exit(1)
}
}
var UnsupportedArchErr = errors.New("unsupported architecture - only darwin/amd64 is supported")
func (dbp *Process) findExecutable(path string) (*macho.File, string, error) {
if path == "" {
path = C.GoString(C.find_executable(C.int(dbp.Pid)))
}
exe, err := macho.Open(path)
if err != nil {
return nil, path, err
}
if exe.Cpu != macho.CpuAmd64 {
return nil, path, UnsupportedArchErr
}
dbp.dwarf, err = exe.DWARF()
if err != nil {
return nil, path, err
}
return exe, path, nil
}
func (dbp *Process) trapWait(pid int) (*Thread, error) {
for {
task := dbp.os.task
port := C.mach_port_wait(dbp.os.portSet, &task, C.int(0))
switch port {
case dbp.os.notificationPort:
// on macOS >= 10.12.1 the task_t changes after an execve, we could
// receive the notification for the death of the pre-execve task_t,
// this could also happen *before* we are notified that our task_t has
// changed.
if dbp.os.task != task {
continue
}
if !dbp.os.initialized {
if pidtask := C.get_task_for_pid(C.int(dbp.Pid)); pidtask != 0 && dbp.os.task != pidtask {
continue
}
}
_, status, err := dbp.wait(dbp.Pid, 0)
if err != nil {
return nil, err
}
dbp.postExit()
return nil, ProcessExitedError{Pid: dbp.Pid, Status: status.ExitStatus()}
case C.MACH_RCV_INTERRUPTED:
if !dbp.halt {
// Call trapWait again, it seems
// MACH_RCV_INTERRUPTED is emitted before
// process natural death _sometimes_.
continue
}
return nil, nil
case 0:
return nil, fmt.Errorf("error while waiting for task")
}
// In macOS 10.12.1 if we received a notification for a task other than
// the inferior's task and the inferior's task is no longer valid, this
// means inferior called execve and its task_t changed.
if dbp.os.task != task && C.task_is_valid(dbp.os.task) == 0 {
dbp.os.task = task
kret := C.reset_exception_ports(dbp.os.task, &dbp.os.exceptionPort, &dbp.os.notificationPort)
if kret != C.KERN_SUCCESS {
return nil, fmt.Errorf("could not follow task across exec: %d\n", kret)
}
}
// Since we cannot be notified of new threads on OS X
// this is as good a time as any to check for them.
dbp.updateThreadList()
th, ok := dbp.Threads[int(port)]
if !ok {
if dbp.halt {
dbp.halt = false
return th, nil
}
if dbp.firstStart || th.singleStepping {
dbp.firstStart = false
return th, nil
}
if err := th.Continue(); err != nil {
return nil, err
}
continue
}
return th, nil
}
}
func (dbp *Process) waitForStop() ([]int, error) {
ports := make([]int, 0, len(dbp.Threads))
count := 0
for {
var task C.task_t
port := C.mach_port_wait(dbp.os.portSet, &task, C.int(1))
if port != 0 && port != dbp.os.notificationPort && port != C.MACH_RCV_INTERRUPTED {
count = 0
ports = append(ports, int(port))
} else {
n := C.num_running_threads(dbp.os.task)
if n == 0 {
return ports, nil
} else if n < 0 {
return nil, fmt.Errorf("error waiting for thread stop %d", n)
} else if count > 16 {
return nil, fmt.Errorf("could not stop process %d", n)
}
}
}
}
func (dbp *Process) setCurrentBreakpoints(trapthread *Thread) error {
ports, err := dbp.waitForStop()
if err != nil {
return err
}
trapthread.SetCurrentBreakpoint()
for _, port := range ports {
if th, ok := dbp.Threads[port]; ok {
err := th.SetCurrentBreakpoint()
if err != nil {
return err
}
}
}
return nil
}
func (dbp *Process) loadProcessInformation(wg *sync.WaitGroup) {
wg.Done()
}
func (dbp *Process) wait(pid, options int) (int, *sys.WaitStatus, error) {
var status sys.WaitStatus
wpid, err := sys.Wait4(pid, &status, options, nil)
return wpid, &status, err
}
func killProcess(pid int) error {
return sys.Kill(pid, sys.SIGINT)
}
func (dbp *Process) exitGuard(err error) error {
if err != ErrContinueThread {
return err
}
_, status, werr := dbp.wait(dbp.Pid, sys.WNOHANG)
if werr == nil && status.Exited() {
dbp.postExit()
return ProcessExitedError{Pid: dbp.Pid, Status: status.ExitStatus()}
}
return err
}
func (dbp *Process) resume() error {
// all threads stopped over a breakpoint are made to step over it
for _, thread := range dbp.Threads {
if thread.CurrentBreakpoint != nil {
if err := thread.StepInstruction(); err != nil {
return err
}
thread.CurrentBreakpoint = nil
}
}
// everything is resumed
for _, thread := range dbp.Threads {
if err := thread.resume(); err != nil {
return dbp.exitGuard(err)
}
}
return nil
}