This wraps the virDomainBlockPeek libvirt function, available since
version 0.4.5.
Signed-off-by: Claudio Bley <cbley@xxxxxxxxxx>
---
src/main/java/org/libvirt/Domain.java | 53 ++++++++++++++++++++++++++++
src/main/java/org/libvirt/jna/Libvirt.java | 4 +++
2 files changed, 57 insertions(+)
diff --git a/src/main/java/org/libvirt/Domain.java b/src/main/java/org/libvirt/Domain.java
index f3fffdd..f57460f 100644
--- a/src/main/java/org/libvirt/Domain.java
+++ b/src/main/java/org/libvirt/Domain.java
@@ -1,5 +1,7 @@
package org.libvirt;
+import java.nio.ByteBuffer;
+
import org.libvirt.event.IOErrorListener;
import org.libvirt.jna.DomainPointer;
import org.libvirt.jna.DomainSnapshotPointer;
@@ -280,6 +282,57 @@ public class Domain {
}
/**
+ * Read the contents of a domain's disk device.
+ * <p>
+ * Typical uses for this are to determine if the domain has
+ * written a Master Boot Record (indicating that the domain has
+ * completed installation), or to try to work out the state of the
+ * domain's filesystems.
+ * <p>
+ * (Note that in the local case you might try to open the block
+ * device or file directly, but that won't work in the remote
+ * case, nor if you don't have sufficient permission. Hence the
+ * need for this call).
+ * <p>
+ * The disk parameter can either be an unambiguous source name of
+ * the block device (the {@code <source file='...'/>} sub-element,
+ * such as "/path/to/image"), or <em>(since 0.9.5)</em> the device
+ * target shorthand (the {@code <target dev='...'/>} sub-element,
+ * such as "xvda").
+ * <p>
+ * Valid names can be found by calling {@link #getXMLDesc} and
+ * inspecting elements within {@code //domain/devices/disk}.
+ * <p>
+ * This method always reads the number of bytes remaining in the
+ * buffer, that is, {@code buffer.remaining()} at the moment this
+ * method is invoked. Upon return the buffer's position will be
+ * equal to the limit, the limit itself will not have changed.
+ *
+ * @param disk the path to the block device, or device shorthand
+ * @param offset the offset within block device
+ * @param buffer the buffer receiving the data
+ */
+ public void blockPeek(String disk, long offset, ByteBuffer buffer) throws LibvirtException {
+ SizeT size = new SizeT();
+
+ // older libvirt has a limitation on the size of data
+ // transferred per request in the remote driver. So, split
+ // larger requests into 64K blocks.
+
+ do {
+ final int req = Math.min(65536, buffer.remaining());
+
+ size.setValue(req);
+
+ processError(libvirt.virDomainBlockPeek(this.VDP, disk, offset, size, buffer, 0));
+
+ buffer.position(buffer.position() + req);
+ } while (buffer.hasRemaining());
+
+ assert buffer.position() == buffer.limit();
+ }
+
+ /**
* Returns block device (disk) stats for block devices attached to this
* domain. The path parameter is the name of the block device. Get this by
* calling virDomainGetXMLDesc and finding the <target dev='...'> attribute
diff --git a/src/main/java/org/libvirt/jna/Libvirt.java b/src/main/java/org/libvirt/jna/Libvirt.java
index 3bd63e1..0452246 100644
--- a/src/main/java/org/libvirt/jna/Libvirt.java
+++ b/src/main/java/org/libvirt/jna/Libvirt.java
@@ -1,5 +1,7 @@
package org.libvirt.jna;
+import java.nio.ByteBuffer;
+
import com.sun.jna.Callback;
import com.sun.jna.Library;
import com.sun.jna.Native;
@@ -243,6 +245,8 @@ public interface Libvirt extends Library {
int virDomainAbortJob(DomainPointer virDomainPtr);
int virDomainAttachDevice(DomainPointer virDomainPtr, String deviceXML);
int virDomainAttachDeviceFlags(DomainPointer virDomainPtr, String deviceXML, int flags);
+ int virDomainBlockPeek(DomainPointer virDomainPtr, String disk, long offset, SizeT size,
+ ByteBuffer buffer, int flags);
int virDomainBlockStats(DomainPointer virDomainPtr, String path, virDomainBlockStats stats, SizeT size);
int virDomainBlockResize(DomainPointer virDomainPtr, String disk, long size, int flags);
int virDomainCoreDump(DomainPointer virDomainPtr, String to, int flags);
--
1.7.9.5
--
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