ZP-987 Allow text keys when using memcache IPC, have a defined mutex

name in memcache, suppress errors on unlinking memcache-down file, use
device id for IPC type (key) in PingTracking and LoopDetection (one
datakey + mutex per device!), check if TopCollector is enabled without
blocking the mutex.

Released under the Affero GNU General Public License (AGPL) version 3.

src/backend/ipcmemcached/ipcmemcachedprovider.php

@@ -47,6 +47,7 @@ require_once("backend/ipcmemcached/config.php");
 
 class IpcMemcachedProvider implements IIpcProvider {
     protected $type;
+    private $typeMutex;
     private $maxWaitCycles;
     private $logWaitCycles;
     private $isDownUntil;
@@ -70,6 +71,7 @@ class IpcMemcachedProvider implements IIpcProvider {
      */
     public function __construct($type, $allocate, $class) {
         $this->type = $type;
+        $this->typeMutex = $type . "MX";
         $this->maxWaitCycles = round(MEMCACHED_MUTEX_TIMEOUT * 1000 / MEMCACHED_BLOCK_WAIT)+1;
         $this->logWaitCycles = round($this->maxWaitCycles/5);
 
@@ -181,20 +183,20 @@ class IpcMemcachedProvider implements IIpcProvider {
         }
 
         $n = 0;
-        while(!$this->memcached->add($this->type+10, true, MEMCACHED_MUTEX_TIMEOUT)) {
+        while(!$this->memcached->add($this->typeMutex, true, MEMCACHED_MUTEX_TIMEOUT)) {
             if (++$n % $this->logWaitCycles == 0) {
-                ZLog::Write(LOGLEVEL_DEBUG, sprintf("IpcMemcachedProvider->BlockMutex() waiting to aquire mutex for type: %s ", $this->type));
+                ZLog::Write(LOGLEVEL_DEBUG, sprintf("IpcMemcachedProvider->BlockMutex() waiting to aquire mutex for type: %s ", $this->typeMutex));
             }
             // wait before retrying
             usleep(MEMCACHED_BLOCK_WAIT * 1000);
             if ($n > $this->maxWaitCycles) {
-                ZLog::Write(LOGLEVEL_ERROR, sprintf("IpcMemcachedProvider->BlockMutex() could not aquire mutex for type: %s. Check memcache service!", $this->type));
+                ZLog::Write(LOGLEVEL_ERROR, sprintf("IpcMemcachedProvider->BlockMutex() could not aquire mutex for type: %s. Check memcache service!", $this->typeMutex));
                 $this->markAsDown();
                 return false;
             }
         }
         if ($n*MEMCACHED_BLOCK_WAIT > 50) {
-            ZLog::Write(LOGLEVEL_WARN, sprintf("IpcMemcachedProvider->BlockMutex() mutex aquired after waiting for %sms for type: %s", ($n*MEMCACHED_BLOCK_WAIT), $this->type));
+            ZLog::Write(LOGLEVEL_WARN, sprintf("IpcMemcachedProvider->BlockMutex() mutex aquired after waiting for %sms for type: %s", ($n*MEMCACHED_BLOCK_WAIT), $this->typeMutex));
         }
         return true;
     }
@@ -207,7 +209,7 @@ class IpcMemcachedProvider implements IIpcProvider {
      * @return boolean
      */
     public function ReleaseMutex() {
-        return $this->memcached->delete($this->type+10);
+        return $this->memcached->delete($this->typeMutex);
     }
 
     /**
@@ -265,7 +267,7 @@ class IpcMemcachedProvider implements IIpcProvider {
                 return $timestamp;
             }
             else {
-                unlink(MEMCACHED_DOWN_LOCK_FILE);
+                @unlink(MEMCACHED_DOWN_LOCK_FILE);
             }
         }
         return 0;

src/lib/core/interprocessdata.php

@@ -88,8 +88,13 @@ abstract class InterProcessData {
             if (!$this->provider_class) {
                 throw new Exception("No IPC provider available");
             }
+            // ZP-987: use an own mutex + storage key for each device on non-shared-memory IPC
+            // this method is not suitable for the TopCollector atm
+            if (!($this instanceof TopCollector) && $this->provider_class !== 'IpcSharedMemoryProvider') {
+                $this->type = Request::GetDeviceID(). "-". $this->type;
+            }
             $this->ipcProvider = new $this->provider_class($this->type, $this->allocate, get_class($this));
-            ZLog::Write(LOGLEVEL_DEBUG, sprintf("%s initialised with IPC provider '%s'", get_class($this), $this->provider_class));
+            ZLog::Write(LOGLEVEL_DEBUG, sprintf("%s initialised with IPC provider '%s' with type '%s'", get_class($this), $this->provider_class, $this->type));
 
         }
         catch (Exception $e) {

src/lib/core/topcollector.php

@@ -144,10 +144,10 @@ class TopCollector extends InterProcessData {
         if ($preserve)
             $this->preserved[] = $addinfo;
 
+        if ($this->isEnabled()) {
+            $ok = false;
             // exclusive block
             if ($this->blockMutex()) {
-
-            if ($this->isEnabled()) {
                 $topdata = ($this->hasData(self::TOPDATA)) ? $this->getData(self::TOPDATA): array();
 
                 $this->checkArrayStructure($topdata);
@@ -155,16 +155,14 @@ class TopCollector extends InterProcessData {
                 // update
                 $topdata[self::$devid][self::$user][self::$pid] = $this->latest;
                 $ok = $this->setData($topdata, self::TOPDATA);
-            }
                 $this->releaseMutex();
             }
             // end exclusive block
-
-        if ($this->isEnabled() === true && !$ok) {
+            if (!$ok) {
                 ZLog::Write(LOGLEVEL_WARN, "TopCollector::AnnounceInformation(): could not write to shared memory. Z-Push top will not display this data.");
                 return false;
             }
-
+        }
         return true;
     }