From 8e42ba4357b6a56cb31637edd2f12e5a36cc530a Mon Sep 17 00:00:00 2001
From: Bruce Weirdan <weirdan@gmail.com>
Date: Sat, 22 Aug 2020 17:01:00 +0300
Subject: [PATCH] Don't hang when pcntl_fork is disabled (#4039)

* Don't hang when pcntl_fork is disabled

Fixes vimeo/psalm#3951

* fix CS
---
 .../Internal/Analyzer/ProjectAnalyzer.php      | 18 +++++++++++++++++-
 src/Psalm/Internal/Fork/Pool.php               |  9 +++++++++
 2 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/src/Psalm/Internal/Analyzer/ProjectAnalyzer.php b/src/Psalm/Internal/Analyzer/ProjectAnalyzer.php
index c9b67f74c64..4b795ddd5dc 100644
--- a/src/Psalm/Internal/Analyzer/ProjectAnalyzer.php
+++ b/src/Psalm/Internal/Analyzer/ProjectAnalyzer.php
@@ -86,6 +86,8 @@
 use function array_map;
 use function end;
 use Psalm\Internal\Codebase\Taint;
+use function ini_get;
+use function in_array;
 
 /**
  * @internal
@@ -454,13 +456,27 @@ public function server($address = '127.0.0.1:12345', bool $socket_server_mode =
                 exit(1);
             }
             fwrite(STDOUT, "Server listening on $address\n");
+
+            $fork_available = true;
             if (!extension_loaded('pcntl')) {
                 fwrite(STDERR, "PCNTL is not available. Only a single connection will be accepted\n");
+                $fork_available = false;
             }
+
+            $disabled_functions = array_map('trim', explode(',', ini_get('disable_functions')));
+            if (in_array('pcntl_fork', $disabled_functions)) {
+                fwrite(
+                    STDERR,
+                    "pcntl_fork() is disabled by php configuration (disable_functions directive)."
+                    . " Only a single connection will be accepted\n"
+                );
+                $fork_available = false;
+            }
+
             while ($socket = stream_socket_accept($tcpServer, -1)) {
                 fwrite(STDOUT, "Connection accepted\n");
                 stream_set_blocking($socket, false);
-                if (extension_loaded('pcntl')) {
+                if ($fork_available) {
                     // If PCNTL is available, fork a child process for the connection
                     // An exit notification will only terminate the child process
                     $pid = pcntl_fork();
diff --git a/src/Psalm/Internal/Fork/Pool.php b/src/Psalm/Internal/Fork/Pool.php
index d784a426961..ca16c21d504 100644
--- a/src/Psalm/Internal/Fork/Pool.php
+++ b/src/Psalm/Internal/Fork/Pool.php
@@ -44,6 +44,8 @@
 use function unserialize;
 use function usleep;
 use function version_compare;
+use function array_map;
+use function in_array;
 
 /**
  * Adapted with relatively few changes from
@@ -115,6 +117,13 @@ public function __construct(
             exit(1);
         }
 
+        $disabled_functions = array_map('trim', explode(',', ini_get('disable_functions')));
+        if (in_array('pcntl_fork', $disabled_functions)) {
+            echo "pcntl_fork() is disabled by php configuration (disable_functions directive).\n"
+                . "Please enable it or run Psalm single-threaded with --threads=1 cli switch.\n";
+            exit(1);
+        }
+
         if (ini_get('pcre.jit') === '1'
             && \PHP_OS === 'Darwin'
             && version_compare(PHP_VERSION, '7.3.0') >= 0