Fix bug #77023: FPM cannot shutdown processes

This change introduces subsequent kill of the process when idle process quit
(SIGQUIT) does not succeed. It can happen in some situations and means that FPM
is not able to scale down in dynamic pm. Using SIGKILL fixes the issue.

Author: bukka

NEWS

@@ -13,6 +13,7 @@ PHP                                                                        NEWS
 - FPM:
   . Fixed bug #76003 (FPM /status reports wrong number of active processe).
     (Jakub Zelenka)
+  . Fixed bug #77023 (FPM cannot shutdown processes). (Jakub Zelenka)
 
 - MySQLi:
   . Fixed bug GH-8267 (MySQLi uses unsupported format specifier on Windows).

sapi/fpm/fpm/fpm_process_ctl.c

@@ -138,6 +138,9 @@ int fpm_pctl_kill(pid_t pid, int how) /* {{{ */
 		case FPM_PCTL_QUIT :
 			s = SIGQUIT;
 			break;
+		case FPM_PCTL_KILL:
+			s = SIGKILL;
+			break;
 		default :
 			break;
 	}
@@ -310,6 +313,17 @@ static void fpm_pctl_check_request_timeout(struct timeval *now) /* {{{ */
 }
 /* }}} */
 
+static void fpm_pctl_kill_idle_child(struct fpm_child_s *child) /* {{{ */
+{
+	if (child->idle_kill) {
+		fpm_pctl_kill(child->pid, FPM_PCTL_KILL);
+	} else {
+		child->idle_kill = 1;
+		fpm_pctl_kill(child->pid, FPM_PCTL_QUIT);
+	}
+}
+/* }}} */
+
 static void fpm_pctl_perform_idle_server_maintenance(struct timeval *now) /* {{{ */
 {
 	struct fpm_worker_pool_s *wp;
@@ -372,8 +386,7 @@ static void fpm_pctl_perform_idle_server_maintenance(struct timeval *now) /* {{{
 			fpm_request_last_activity(last_idle_child, &last);
 			fpm_clock_get(&now);
 			if (last.tv_sec < now.tv_sec - wp->config->pm_process_idle_timeout) {
-				last_idle_child->idle_kill = 1;
-				fpm_pctl_kill(last_idle_child->pid, FPM_PCTL_QUIT);
+				fpm_pctl_kill_idle_child(last_idle_child);
 			}
 
 			continue;
@@ -385,8 +398,7 @@ static void fpm_pctl_perform_idle_server_maintenance(struct timeval *now) /* {{{
 		zlog(ZLOG_DEBUG, "[pool %s] currently %d active children, %d spare children, %d running children. Spawning rate %d", wp->config->name, active, idle, wp->running_children, wp->idle_spawn_rate);
 
 		if (idle > wp->config->pm_max_spare_servers && last_idle_child) {
-			last_idle_child->idle_kill = 1;
-			fpm_pctl_kill(last_idle_child->pid, FPM_PCTL_QUIT);
+			fpm_pctl_kill_idle_child(last_idle_child);
 			wp->idle_spawn_rate = 1;
 			continue;
 		}

sapi/fpm/fpm/fpm_process_ctl.h

@@ -44,7 +44,8 @@ enum {
 	FPM_PCTL_TERM,
 	FPM_PCTL_STOP,
 	FPM_PCTL_CONT,
-	FPM_PCTL_QUIT
+	FPM_PCTL_QUIT,
+	FPM_PCTL_KILL
 };
 
 #endif

sapi/fpm/tests/bug77023-pm-dynamic-blocking-sigquit.phpt

@@ -0,0 +1,65 @@
+--TEST--
+FPM: Blocked SIGQUIT prevents idle process to be killed
+--EXTENSIONS--
+pcntl
+--SKIPIF--
+<?php
+include "skipif.inc";
+if (!function_exists('pcntl_sigprocmask')) die('skip Requires pcntl_sigprocmask()');
+if (getenv('SKIP_SLOW_TESTS')) die('skip slow tests excluded by request');
+?>
+--FILE--
+<?php
+
+require_once "tester.inc";
+
+$cfg = <<<EOT
+[global]
+error_log = {{FILE:LOG}}
+pid = {{FILE:PID}}
+[unconfined]
+listen = {{ADDR}}
+pm.status_path = /status
+pm = dynamic
+pm.max_children = 2
+pm.start_servers = 1
+pm.min_spare_servers = 1
+pm.max_spare_servers = 1
+EOT;
+
+$code = <<<EOT
+<?php
+pcntl_sigprocmask(SIG_BLOCK, [SIGQUIT, SIGTERM]);
+usleep(300000);
+EOT;
+
+
+$tester = new FPM\Tester($cfg, $code);
+$tester->start();
+$tester->expectLogStartNotices();
+$tester->multiRequest(2);
+$tester->status([
+    'total processes' => 2,
+]);
+// wait for process to be killed
+sleep(7);
+$tester->expectLogWarning('child \\d+ exited on signal 9 \\(SIGKILL\\) after \\d+.\\d+ seconds from start', 'unconfined');
+$tester->expectLogNotice('child \\d+ started', 'unconfined');
+$tester->expectLogWarning('child \\d+ exited on signal 9 \\(SIGKILL\\) after \\d+.\\d+ seconds from start', 'unconfined');
+$tester->expectLogNotice('child \\d+ started', 'unconfined');
+$tester->status([
+    'total processes' => 1,
+]);
+$tester->terminate();
+$tester->expectLogTerminatingNotices();
+$tester->close();
+
+?>
+Done
+--EXPECT--
+Done
+--CLEAN--
+<?php
+require_once "tester.inc";
+FPM\Tester::clean();
+?>