Make ExtractErrno a function

PiperOrigin-RevId: 306891171

pkg/sentry/kernel/task_run.go

@@ -353,7 +353,7 @@ func (app *runApp) execute(t *Task) taskRunState {
 	default:
 		// What happened? Can't continue.
 		t.Warningf("Unexpected SwitchToApp error: %v", err)
-		t.PrepareExit(ExitStatus{Code: t.ExtractErrno(err, -1)})
+		t.PrepareExit(ExitStatus{Code: ExtractErrno(err, -1)})
 		return (*runExit)(nil)
 	}
 }

pkg/sentry/kernel/task_signals.go

@@ -174,7 +174,7 @@ func (t *Task) deliverSignal(info *arch.SignalInfo, act arch.SignalAct) taskRunS
 					fallthrough
 				case (sre == ERESTARTSYS && !act.IsRestart()):
 					t.Debugf("Not restarting syscall %d after errno %d: interrupted by signal %d", t.Arch().SyscallNo(), sre, info.Signo)
-					t.Arch().SetReturn(uintptr(-t.ExtractErrno(syserror.EINTR, -1)))
+					t.Arch().SetReturn(uintptr(-ExtractErrno(syserror.EINTR, -1)))
 				default:
 					t.Debugf("Restarting syscall %d after errno %d: interrupted by signal %d", t.Arch().SyscallNo(), sre, info.Signo)
 					t.Arch().RestartSyscall()

pkg/sentry/kernel/task_syscall.go

@@ -312,7 +312,7 @@ func (t *Task) doSyscallInvoke(sysno uintptr, args arch.SyscallArguments) taskRu
 			return ctrl.next
 		}
 	} else if err != nil {
-		t.Arch().SetReturn(uintptr(-t.ExtractErrno(err, int(sysno))))
+		t.Arch().SetReturn(uintptr(-ExtractErrno(err, int(sysno))))
 		t.haveSyscallReturn = true
 	} else {
 		t.Arch().SetReturn(rval)
@@ -431,7 +431,7 @@ func (t *Task) doVsyscallInvoke(sysno uintptr, args arch.SyscallArguments, calle
 			// A return is not emulated in this case.
 			return (*runApp)(nil)
 		}
-		t.Arch().SetReturn(uintptr(-t.ExtractErrno(err, int(sysno))))
+		t.Arch().SetReturn(uintptr(-ExtractErrno(err, int(sysno))))
 	}
 	t.Arch().SetIP(t.Arch().Value(caller))
 	t.Arch().SetStack(t.Arch().Stack() + uintptr(t.Arch().Width()))
@@ -441,7 +441,7 @@ func (t *Task) doVsyscallInvoke(sysno uintptr, args arch.SyscallArguments, calle
 // ExtractErrno extracts an integer error number from the error.
 // The syscall number is purely for context in the error case. Use -1 if
 // syscall number is unknown.
-func (t *Task) ExtractErrno(err error, sysno int) int {
+func ExtractErrno(err error, sysno int) int {
 	switch err := err.(type) {
 	case nil:
 		return 0
@@ -455,11 +455,11 @@ func (t *Task) ExtractErrno(err error, sysno int) int {
 		// handled (and the SIGBUS is delivered).
 		return int(syscall.EFAULT)
 	case *os.PathError:
-		return t.ExtractErrno(err.Err, sysno)
+		return ExtractErrno(err.Err, sysno)
 	case *os.LinkError:
-		return t.ExtractErrno(err.Err, sysno)
+		return ExtractErrno(err.Err, sysno)
 	case *os.SyscallError:
-		return t.ExtractErrno(err.Err, sysno)
+		return ExtractErrno(err.Err, sysno)
 	default:
 		if errno, ok := syserror.TranslateError(err); ok {
 			return int(errno)

pkg/sentry/strace/strace.go

@@ -719,7 +719,7 @@ func (s SyscallMap) SyscallEnter(t *kernel.Task, sysno uintptr, args arch.Syscal
 // SyscallExit implements kernel.Stracer.SyscallExit. It logs the syscall
 // exit trace.
 func (s SyscallMap) SyscallExit(context interface{}, t *kernel.Task, sysno, rval uintptr, err error) {
-	errno := t.ExtractErrno(err, int(sysno))
+	errno := kernel.ExtractErrno(err, int(sysno))
 	c := context.(*syscallContext)
 
 	elapsed := time.Since(c.start)

pkg/sentry/syscalls/linux/sys_aio.go

@@ -290,7 +290,7 @@ func performCallback(t *kernel.Task, file *fs.File, cbAddr usermem.Addr, cb *ioC
 	// Update the result.
 	if err != nil {
 		err = handleIOError(t, ev.Result != 0 /* partial */, err, nil /* never interrupted */, "aio", file)
-		ev.Result = -int64(t.ExtractErrno(err, 0))
+		ev.Result = -int64(kernel.ExtractErrno(err, 0))
 	}
 
 	file.DecRef()