From 3a144049e58168bf47932b7d357648786633fee8 Mon Sep 17 00:00:00 2001
From: Thierry Bugier <tbugier@teclib.com>
Date: Thu, 12 Jul 2018 09:29:23 +0200
Subject: [PATCH] fix(invitation): add locks to protect concurrent rules
 edition

The purpose is to avoid simultaneous modification of rules in some specific cases

Signed-off-by: Thierry Bugier <tbugier@teclib.com>
---
 .../entityruleeditionexception.class.php      |  6 +++
 inc/fusioninventory.class.php                 | 41 ++++++++++++++++++-
 2 files changed, 46 insertions(+), 1 deletion(-)
 create mode 100644 inc/exception/entityruleeditionexception.class.php

diff --git a/inc/exception/entityruleeditionexception.class.php b/inc/exception/entityruleeditionexception.class.php
new file mode 100644
index 00000000..bf1cc87c
--- /dev/null
+++ b/inc/exception/entityruleeditionexception.class.php
@@ -0,0 +1,6 @@
+<?php
+
+namespace GlpiPlugin\Flyvemdm\Exception;
+
+
+class EntityRuleEditionException extends \Exception {}
\ No newline at end of file
diff --git a/inc/fusioninventory.class.php b/inc/fusioninventory.class.php
index 0889f9a3..b06b5f46 100644
--- a/inc/fusioninventory.class.php
+++ b/inc/fusioninventory.class.php
@@ -29,7 +29,8 @@
  * ------------------------------------------------------------------------------
  */
 
- use GlpiPlugin\Flyvemdm\Exception\FusionInventoryRuleInconsistency;
+use GlpiPlugin\Flyvemdm\Exception\FusionInventoryRuleInconsistency;
+use GlpiPlugin\Flyvemdm\Exception\EntityRuleEditionException;
 
 if (!defined('GLPI_ROOT')) {
    die("Sorry. You can't access this file directly");
@@ -39,6 +40,9 @@ class PluginFlyvemdmFusionInventory {
 
    const RULE_NAME = 'Flyve MDM invitation to entity';
 
+   const LOCK_NAME = 'flyvemdm_entityRule';
+
+
    /**
     * Creates or updates an entity rule
     *
@@ -52,6 +56,10 @@ public function addInvitationRule(PluginFlyvemdmInvitation $invitation) {
          Session::addMessageAfterRedirect(__('Unable to get rule for entity', 'flyvemdm'),
             true, ERROR);
          return;
+      } catch (EntityRuleEditionException $exception) {
+         Session::addMessageAfterRedirect(__('Cannot get lock for entity rules edition', 'flyvemdm'),
+            true, ERROR);
+         return;
       }
 
       $ruleCriteria = new RuleCriteria();
@@ -117,6 +125,19 @@ public function deleteInvitationRuleCriteria(PluginFlyvemdmInvitation $invitatio
       ]);
 
       $ruleId = $row[$ruleFk];
+
+      // get a lock
+      $attempts = 0;
+      $locked = 0;
+      do {
+         $locked = $DB->getLock(self::LOCK_NAME);
+         usleep(50000); // 50 milliseconds
+         $attempts++;
+      } while ($locked !== 1 && $attempts < 10);
+      if ($locked !== 1) {
+         return; // No lock, then give up disabling
+      }
+
       $rows = $ruleCriteria->find("`$ruleFk` = '$ruleId' AND `criteria` = 'tag' AND `condition` = '0'");
       if (count($rows) === 0) {
          $rule = new PluginFusioninventoryInventoryRuleEntity();
@@ -125,6 +146,7 @@ public function deleteInvitationRuleCriteria(PluginFlyvemdmInvitation $invitatio
             'is_active' => '0',
          ]);
       }
+      $DB->releaseLock(self::LOCK_NAME);
    }
 
    /**
@@ -144,10 +166,23 @@ private function getRuleCriteriaValue(PluginFlyvemdmInvitation $invitation) {
     *
     * @return PluginFusioninventoryInventoryRuleEntity|null
     * @throws FusionInventoryRuleInconsistency
+    * @throws EntityRuleEditionException
     */
    private function getRule($entityId, $create = true) {
       global $DB;
 
+      // get a lock
+      $attempts = 0;
+      $locked = 0;
+      do {
+         $locked = $DB->getLock(self::LOCK_NAME);
+         usleep(50000); // 50 milliseconds
+         $attempts++;
+      } while ($locked !== 1 && $attempts < 10);
+      if ($locked !== 1) {
+         throw new EntityRuleEditionException(__('Cannot get lock for entity rules edition'));
+      }
+
       $ruleEntityTable = PluginFusioninventoryInventoryRuleEntity::getTable();
       $ruleActionTable = RuleAction::getTable();
       $request = [
@@ -175,13 +210,16 @@ private function getRule($entityId, $create = true) {
          $rule = new PluginFusioninventoryInventoryRuleEntity();
          $row = $result->next();
          $rule->getFromDB($row['id']);
+         $DB->releaseLock(self::LOCK_NAME);
          return $rule;
       }
       if ($result->count() > 1) {
+         $DB->releaseLock(self::LOCK_NAME);
          throw new FusionInventoryRuleInconsistency(__('Import rule is not unique'));
       }
 
       if (!$create) {
+         $DB->releaseLock(self::LOCK_NAME);
          return null;
       }
 
@@ -203,6 +241,7 @@ private function getRule($entityId, $create = true) {
          'field'                    => Entity::getForeignKeyField(),
          'value'                    => $entityId,
       ]);
+      $DB->releaseLock(self::LOCK_NAME);
       return $rule;
    }
 }
\ No newline at end of file