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cmd/geth, console: support interrupting the js console (#23387)

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Previously, Ctrl-C (SIGINT) was ignored during JS execution, so it was not
possible to get out of infinite loops in the console. With this change,
Ctrl-C now interrupts JS.

Fixes #23344

Co-authored-by: Sina Mahmoodi <itz.s1na@gmail.com>
Co-authored-by: Felix Lange <fjl@twurst.com>
This commit is contained in:
Martin Holst Swende
2021-12-11 16:51:05 +01:00
committed by GitHub
parent ae8ff2661d
commit 72c2c0ae7e
5 changed files with 193 additions and 63 deletions
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123
console/console.go
View File

@ -17,6 +17,7 @@
package console
import (
"errors"
"fmt"
"io"
"io/ioutil"
@ -26,6 +27,7 @@ import (
"regexp"
"sort"
"strings"
"sync"
"syscall"
"github.com/dop251/goja"
@ -74,6 +76,13 @@ type Console struct {
histPath string // Absolute path to the console scrollback history
history []string // Scroll history maintained by the console
printer io.Writer // Output writer to serialize any display strings to
interactiveStopped chan struct{}
stopInteractiveCh chan struct{}
signalReceived chan struct{}
stopped chan struct{}
wg sync.WaitGroup
stopOnce sync.Once
}
// New initializes a JavaScript interpreted runtime environment and sets defaults
@ -92,12 +101,16 @@ func New(config Config) (*Console, error) {
// Initialize the console and return
console := &Console{
client: config.Client,
jsre: jsre.New(config.DocRoot, config.Printer),
prompt: config.Prompt,
prompter: config.Prompter,
printer: config.Printer,
histPath: filepath.Join(config.DataDir, HistoryFile),
client: config.Client,
jsre: jsre.New(config.DocRoot, config.Printer),
prompt: config.Prompt,
prompter: config.Prompter,
printer: config.Printer,
histPath: filepath.Join(config.DataDir, HistoryFile),
interactiveStopped: make(chan struct{}),
stopInteractiveCh: make(chan struct{}),
signalReceived: make(chan struct{}, 1),
stopped: make(chan struct{}),
}
if err := os.MkdirAll(config.DataDir, 0700); err != nil {
return nil, err
@ -105,6 +118,10 @@ func New(config Config) (*Console, error) {
if err := console.init(config.Preload); err != nil {
return nil, err
}
console.wg.Add(1)
go console.interruptHandler()
return console, nil
}
@ -337,9 +354,63 @@ func (c *Console) Evaluate(statement string) {
}
}()
c.jsre.Evaluate(statement, c.printer)
// Avoid exiting Interactive when jsre was interrupted by SIGINT.
c.clearSignalReceived()
}
// Interactive starts an interactive user session, where input is propted from
// interruptHandler runs in its own goroutine and waits for signals.
// When a signal is received, it interrupts the JS interpreter.
func (c *Console) interruptHandler() {
defer c.wg.Done()
// During Interactive, liner inhibits the signal while it is prompting for
// input. However, the signal will be received while evaluating JS.
//
// On unsupported terminals, SIGINT can also happen while prompting.
// Unfortunately, it is not possible to abort the prompt in this case and
// the c.readLines goroutine leaks.
sig := make(chan os.Signal, 1)
signal.Notify(sig, syscall.SIGINT)
defer signal.Stop(sig)
for {
select {
case <-sig:
c.setSignalReceived()
c.jsre.Interrupt(errors.New("interrupted"))
case <-c.stopInteractiveCh:
close(c.interactiveStopped)
c.jsre.Interrupt(errors.New("interrupted"))
case <-c.stopped:
return
}
}
}
func (c *Console) setSignalReceived() {
select {
case c.signalReceived <- struct{}{}:
default:
}
}
func (c *Console) clearSignalReceived() {
select {
case <-c.signalReceived:
default:
}
}
// StopInteractive causes Interactive to return as soon as possible.
func (c *Console) StopInteractive() {
select {
case c.stopInteractiveCh <- struct{}{}:
case <-c.stopped:
}
}
// Interactive starts an interactive user session, where in.put is propted from
// the configured user prompter.
func (c *Console) Interactive() {
var (
@ -349,15 +420,11 @@ func (c *Console) Interactive() {
inputLine = make(chan string, 1) // receives user input
inputErr = make(chan error, 1) // receives liner errors
requestLine = make(chan string) // requests a line of input
interrupt = make(chan os.Signal, 1)
)
// Monitor Ctrl-C. While liner does turn on the relevant terminal mode bits to avoid
// the signal, a signal can still be received for unsupported terminals. Unfortunately
// there is no way to cancel the line reader when this happens. The readLines
// goroutine will be leaked in this case.
signal.Notify(interrupt, syscall.SIGINT, syscall.SIGTERM)
defer signal.Stop(interrupt)
defer func() {
c.writeHistory()
}()
// The line reader runs in a separate goroutine.
go c.readLines(inputLine, inputErr, requestLine)
@ -368,7 +435,14 @@ func (c *Console) Interactive() {
requestLine <- prompt
select {
case <-interrupt:
case <-c.interactiveStopped:
fmt.Fprintln(c.printer, "node is down, exiting console")
return
case <-c.signalReceived:
// SIGINT received while prompting for input -> unsupported terminal.
// I'm not sure if the best choice would be to leave the console running here.
// Bash keeps running in this case. node.js does not.
fmt.Fprintln(c.printer, "caught interrupt, exiting")
return
@ -476,12 +550,19 @@ func (c *Console) Execute(path string) error {
// Stop cleans up the console and terminates the runtime environment.
func (c *Console) Stop(graceful bool) error {
if err := ioutil.WriteFile(c.histPath, []byte(strings.Join(c.history, "\n")), 0600); err != nil {
return err
}
if err := os.Chmod(c.histPath, 0600); err != nil { // Force 0600, even if it was different previously
return err
}
c.stopOnce.Do(func() {
// Stop the interrupt handler.
close(c.stopped)
c.wg.Wait()
})
c.jsre.Stop(graceful)
return nil
}
func (c *Console) writeHistory() error {
if err := ioutil.WriteFile(c.histPath, []byte(strings.Join(c.history, "\n")), 0600); err != nil {
return err
}
return os.Chmod(c.histPath, 0600) // Force 0600, even if it was different previously
}