Re: [libvirt] alignment of data fields when compiling with mingwin

Hi Matthias, I'm working on the virConnectOpenAuth method C# binding. And in fact, It partially work. Let me explain you : I have defined the virConnectAuth struct by this binding : ///<summary> /// Structure to handle connection authentication ///</summary> [StructLayout(LayoutKind.Sequential)] public struct virConnectAuth { /// <summary> /// List of supported virConnectCredentialType values, should be a IntPtr to an int array or to a virConnectCredentialType array /// </summary> public IntPtr credtypes; ///<summary> /// Number of virConnectCredentialType in credtypes ///</summary> [MarshalAs(UnmanagedType.U4)] public uint ncredtype; ///<summary> /// Callback used to collect credentials, a virConnectAuthCallback delegate in bindings ///</summary> [MarshalAs(UnmanagedType.FunctionPtr)] public virConnectAuthCallback cb; ///<summary> /// Data transported with callback, should be a IntPtr on what you want ///</summary> public IntPtr cbdata; } And I have defined the virConnectCredential struct by this binding : ///<summary> /// Credential structure ///</summary> [StructLayout(LayoutKind.Sequential)] public struct virConnectCredential { ///<summary> /// One of virConnectCredentialType constants ///</summary> [MarshalAs(UnmanagedType.I4)] public virConnectCredentialType type; ///<summary> /// Prompt to show to user ///</summary> [MarshalAs(UnmanagedType.LPStr)] public string prompt; ///<summary> /// Additional challenge to show ///</summary> [MarshalAs(UnmanagedType.LPStr)] public string challenge; ///<summary> /// Optional default result ///</summary> [MarshalAs(UnmanagedType.LPStr)] public string defresult; ///<summary> /// Result to be filled with user response (or defresult). An IntPtr to a marshalled allocated string ///</summary> [MarshalAs(UnmanagedType.LPStr)] public string result; ///<summary> /// Length of the result ///</summary> [MarshalAs(UnmanagedType.U4)] public uint resultlen; } Now, I have made a little code to connect to an esx hypervisor like this : ... some init stuff... // Define the virConnectAuth struct virConnectAuth auth = new virConnectAuth { cbdata = authDataPtr, cb = AuthCallback, credtypes = credtypesPtr, ncredtype = (uint)credtypes.Length }; IntPtr conn = libVirt.virConnectOpenAuth(tbURI.Text, ref auth, 0); I have the call back method "AuthCallback" defined like this : private int AuthCallback(IntPtr creds, uint ncred, IntPtr cbdata) { AuthData authData = (AuthData) Marshal.PtrToStructure(cbdata, typeof (AuthData)); int offset = 0; int credIndex = 0; while (credIndex < ncred) { IntPtr currentCred = new IntPtr(creds.ToInt32() + offset); virConnectCredential cred = (virConnectCredential) Marshal.PtrToStructure(currentCred, typeof (virConnectCredential)); offset += Marshal.SizeOf(cred); switch(cred.type) { case virConnectCredentialType.VIR_CRED_AUTHNAME: cred.result = authData.user_name; cred.resultlen = (uint)authData.user_name.Length; break; case virConnectCredentialType.VIR_CRED_PASSPHRASE: cred.result = authData.password; cred.resultlen = (uint) authData.password.Length; break; default: return -1; } Marshal.StructureToPtr(cred, currentCred, true); credIndex++; } return 0; } When I test this code, all seems to work well, I mean the "AuthCallback" method is called twice, once for authname and once for passphrase. But when I run my code in a debugger of Visual Studio I have these messages : HEAP[Win32_virConnectOpenAuth.exe]: Invalid address specified to RtlFreeHeap( 00700000, 00EE6D78 ) HEAP[Win32_virConnectOpenAuth.exe]: Invalid address specified to RtlFreeHeap( 00700000, 00EE6A80 ) HEAP[Win32_virConnectOpenAuth.exe]: Invalid address specified to RtlFreeHeap( 00700000, 00EE6D78 ) HEAP[Win32_virConnectOpenAuth.exe]: Invalid address specified to RtlFreeHeap( 00700000, 00EE6A80 ) HEAP[Win32_virConnectOpenAuth.exe]: Invalid address specified to RtlFreeHeap( 00EE0000, 007DE480 ) but the connection is done, and I am able to list domains of the hypervisor for example. The real problem is that this program only work inside the the visual studio debugger, when I launch the executable without debugger, it fails. So I am searching why this doesn't work, I want to check the bindings. And I also want to try to fill the "result" member of the virConnectCredential structure directly to understanding what can be the problem. Anyway, thanks ofr these informations, this can help. Best regards, Arnaud -------------------------------------------------- From: "Matthias Bolte" <matthias.bolte(a)googlemail.com&gt; Sent: Sunday, October 17, 2010 12:04 PM To: <arnaud.champion(a)devatom.fr&gt; Cc: <libvir-list(a)redhat.com&gt; Subject: Re: [libvirt] alignment of data fields when compiling with mingwin