Re: [libvirt] Memory free in libvirt JNA

At Wed, 12 Sep 2012 20:23:28 +0800, Daniel Veillard wrote: I did notice the same thing (but was on vacation for quite some time). I already have a fix for virDomainGetSchedulerType in my local repository (see below). I'm using virFree to free the allocated memory which adds another level of indirection (PointerByReference). This is because JNA does not provide access to the C free() function by itself, AFAICS. -- 8< --- From: Claudio Bley <cbley(a)av-test.de&gt; Date: Fri, 24 Aug 2012 11:09:49 +0200 Subject: [PATCH] Fix memory leak for virDomainGetSchedulerType. The string returned by virDomainGetSchedulerType must be free'd explicitly. JNA docs say that we have to use a Pointer as a return type and free it ourselves. So, simply use virFree for that matter. --- src/main/java/org/libvirt/Domain.java | 13 +++++++++---- src/main/java/org/libvirt/jna/Libvirt.java | 6 +++++- 2 files changed, 14 insertions(+), 5 deletions(-) diff --git a/src/main/java/org/libvirt/Domain.java b/src/main/java/org/libvirt/Domain.java index 1f15ee8..fc1f665 100644 --- a/src/main/java/org/libvirt/Domain.java +++ b/src/main/java/org/libvirt/Domain.java @@ -14,7 +14,9 @@ import org.libvirt.jna.virVcpuInfo; import com.sun.jna.Native; import com.sun.jna.NativeLong; +import com.sun.jna.Pointer; import com.sun.jna.ptr.IntByReference; +import com.sun.jna.ptr.PointerByReference; /** * A virtual machine defined within libvirt. @@ -443,9 +445,11 @@ public class Domain { public SchedParameter[] getSchedulerParameters() throws LibvirtException { IntByReference nParams = new IntByReference(); SchedParameter[] returnValue = new SchedParameter[0]; - String scheduler = libvirt.virDomainGetSchedulerType(VDP, nParams); + Pointer pScheduler = libvirt.virDomainGetSchedulerType(VDP, nParams); processError(); - if (scheduler != null) { + if (pScheduler != null) { + String scheduler = pScheduler.getString(0); + libvirt.virFree(new PointerByReference(pScheduler)); virSchedParameter[] nativeParams = new virSchedParameter[nParams.getValue()]; returnValue = new SchedParameter[nParams.getValue()]; libvirt.virDomainGetSchedulerParameters(VDP, nativeParams, nParams); @@ -470,10 +474,11 @@ public class Domain { */ public String[] getSchedulerType() throws LibvirtException { IntByReference nParams = new IntByReference(); - String returnValue = libvirt.virDomainGetSchedulerType(VDP, nParams); + Pointer pScheduler = libvirt.virDomainGetSchedulerType(VDP, nParams); processError(); String[] array = new String[1]; - array[0] = returnValue; + array[0] = pScheduler.getString(0); + libvirt.virFree(new PointerByReference(pScheduler)); return array; } diff --git a/src/main/java/org/libvirt/jna/Libvirt.java b/src/main/java/org/libvirt/jna/Libvirt.java index dc3a54b..e68d9ed 100644 --- a/src/main/java/org/libvirt/jna/Libvirt.java +++ b/src/main/java/org/libvirt/jna/Libvirt.java @@ -7,6 +7,7 @@ import com.sun.jna.NativeLong; import com.sun.jna.Pointer; import com.sun.jna.ptr.IntByReference; import com.sun.jna.ptr.LongByReference; +import com.sun.jna.ptr.PointerByReference; /** * The libvirt interface which is exposed via JNA. The complete API is @@ -55,6 +56,9 @@ import com.sun.jna.ptr.LongByReference; * */ public interface Libvirt extends Library { + // Memory management + void virFree(PointerByReference ptr); + // Callbacks /** * Callback interface for authorization @@ -186,7 +190,7 @@ public interface Libvirt extends Library { public String virDomainGetOSType(DomainPointer virDomainPtr); public int virDomainGetSchedulerParameters(DomainPointer virDomainPtr, virSchedParameter[] params, IntByReference nparams); - public String virDomainGetSchedulerType(DomainPointer virDomainPtr, IntByReference nparams); + Pointer virDomainGetSchedulerType(DomainPointer virDomainPtr, IntByReference nparams); public int virDomainGetUUID(DomainPointer virDomainPtr, byte[] uuidString); public int virDomainGetUUIDString(DomainPointer virDomainPtr, byte[] uuidString); public int virDomainGetVcpus(DomainPointer virDomainPtr, virVcpuInfo[] info, int maxInfo, byte[] cpumaps, int maplen); -- 1.7.11.msysgit.0 -- AV-Test GmbH, Henricistraße 20, 04155 Leipzig, Germany Phone: +49 341 265 310 19 Web:<http://www.av-test.org> Eingetragen am / Registered at: Amtsgericht Stendal (HRB 114076) Geschaeftsfuehrer (CEO): Andreas Marx, Guido Habicht, Maik Morgenstern