157 lines
4.4 KiB
PHP
157 lines
4.4 KiB
PHP
<?php
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/*
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* This file is part of the Symfony package.
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*
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* (c) Fabien Potencier <fabien@symfony.com>
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*
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* For the full copyright and license information, please view the LICENSE
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* file that was distributed with this source code.
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*/
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namespace Symfony\Component\Console\Helper;
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/**
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* TerminalInputHelper stops Ctrl-C and similar signals from leaving the terminal in
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* an unusable state if its settings have been modified when reading user input.
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* This can be an issue on non-Windows platforms.
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*
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* Usage:
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*
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* $inputHelper = new TerminalInputHelper($inputStream);
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*
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* ...change terminal settings
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*
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* // Wait for input before all input reads
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* $inputHelper->waitForInput();
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*
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* ...read input
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*
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* // Call finish to restore terminal settings and signal handlers
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* $inputHelper->finish()
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*
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* @internal
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*/
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final class TerminalInputHelper
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{
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/** @var resource */
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private $inputStream;
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private bool $isStdin;
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private string $initialState = '';
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private int $signalToKill = 0;
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private array $signalHandlers = [];
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private array $targetSignals = [];
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private bool $withStty;
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/**
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* @param resource $inputStream
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*
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* @throws \RuntimeException If unable to read terminal settings
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*/
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public function __construct($inputStream, bool $withStty = true)
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{
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$this->inputStream = $inputStream;
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$this->isStdin = 'php://stdin' === stream_get_meta_data($inputStream)['uri'];
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$this->withStty = $withStty;
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if ($withStty) {
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if (!\is_string($state = shell_exec('stty -g'))) {
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throw new \RuntimeException('Unable to read the terminal settings.');
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}
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$this->initialState = $state;
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$this->createSignalHandlers();
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}
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}
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/**
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* Waits for input.
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*/
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public function waitForInput(): void
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{
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if ($this->isStdin) {
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$r = [$this->inputStream];
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$w = [];
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// Allow signal handlers to run
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while (0 === @stream_select($r, $w, $w, 0, 100)) {
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$r = [$this->inputStream];
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}
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}
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if ($this->withStty) {
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$this->checkForKillSignal();
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}
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}
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/**
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* Restores terminal state and signal handlers.
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*/
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public function finish(): void
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{
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if (!$this->withStty) {
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return;
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}
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// Safeguard in case an unhandled kill signal exists
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$this->checkForKillSignal();
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shell_exec('stty '.$this->initialState);
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$this->signalToKill = 0;
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foreach ($this->signalHandlers as $signal => $originalHandler) {
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pcntl_signal($signal, $originalHandler);
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}
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$this->signalHandlers = [];
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$this->targetSignals = [];
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}
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private function createSignalHandlers(): void
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{
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if (!\function_exists('pcntl_async_signals') || !\function_exists('pcntl_signal')) {
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return;
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}
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pcntl_async_signals(true);
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$this->targetSignals = [\SIGINT, \SIGQUIT, \SIGTERM];
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foreach ($this->targetSignals as $signal) {
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$this->signalHandlers[$signal] = pcntl_signal_get_handler($signal);
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pcntl_signal($signal, function ($signal) {
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// Save current state, then restore to initial state
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$currentState = shell_exec('stty -g');
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shell_exec('stty '.$this->initialState);
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$originalHandler = $this->signalHandlers[$signal];
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if (\is_callable($originalHandler)) {
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$originalHandler($signal);
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// Handler did not exit, so restore to current state
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shell_exec('stty '.$currentState);
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return;
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}
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// Not a callable, so SIG_DFL or SIG_IGN
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if (\SIG_DFL === $originalHandler) {
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$this->signalToKill = $signal;
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}
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});
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}
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}
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private function checkForKillSignal(): void
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{
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if (\in_array($this->signalToKill, $this->targetSignals, true)) {
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// Try posix_kill
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if (\function_exists('posix_kill')) {
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pcntl_signal($this->signalToKill, \SIG_DFL);
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posix_kill(getmypid(), $this->signalToKill);
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}
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// Best attempt fallback
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exit(128 + $this->signalToKill);
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}
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}
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}
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