Re: [Libvir] [PATCH] Add virConnectGetHostname and virConnectGetURI calls, virsh commands, and some related fixes

This patch adds two calls: /** + * virConnectGetHostname: + * @conn: pointer to a hypervisor connection + * + * This returns the system hostname on which the hypervisor is + * running (the result of the gethostname(2) system call). If + * we are connected to a remote system, then this returns the + * hostname of the remote system. + * + * Returns the hostname which must be freed by the caller, or + * NULL if there was an error. + */ +char * +virConnectGetHostname (virConnectPtr conn) and: +/** + * virConnectGetURI: + * @conn: pointer to a hypervisor connection + * + * This returns the URI (name) of the hypervisor connection. + * Normally this is the same as or similar to the string passed + * to the virConnectOpen/virConnectOpenReadOnly call, but + * the driver may make the URI canonical. If name == NULL + * was passed to virConnectOpen, then the driver will return + * a non-NULL URI which can be used to connect to the same + * hypervisor later. + * + * Returns the URI string which must be freed by the caller, or + * NULL if there was an error. + */ +char * +virConnectGetURI (virConnectPtr conn)

It also fixes a kind of accidental memory leak which turns out not to be a memory leak. In the current version of libvirt CVS, when using remote connections, remote's private data is not freed by remote_internal.c. However it turns out that it _is_ freed by qemuNetworkClose. Obviously some confusion there, but this patch fixes that. (Fixing that is a dependency of this patch, which is why the two are done together in one patch).

I've added "virsh hostname" and "virsh uri" commands: $ src/virsh -c test:///default uri test:///default $ src/virsh -c test:///default hostname localhost.localdomain

(Yeah, I haven't set the hostname on this machine ...) I've updated the Xen, test and remote drivers to support the calls. However I didn't update qemu because of Dan's big changes to qemu. Once we have decided whether to put in Dan's changes, I'll go back and implement this for qemu. (I'm actually not sure I would need to implement them, if remote supports the calls already).

I haven't updated the Python bindings, but will do so next.

I decided not to implement the proposed virConnectGetTransport call because I think it needs more thought. It would obviously be useful to

find out whether the current connection is local or remote, encrypted or unencrypted, authenticated or unauthenticated, because all of these things could be usefully communicated back to the user by icons in virt-manager. Simply returning the transport name doesn't really do this. The user might also want to find out _how_ the session is encrypted (what TLS parameters are in use), and again a simple string can't do that. Before applying this patch you will need to do: rm qemud/remote_dispatch_localvars.h \ qemud/remote_dispatch_proc_switch.h \ qemud/remote_dispatch_prototypes.h \ qemud/remote_protocol.c \ qemud/remote_protocol.h and after applying you will need to do: make -C qemud remote_protocol.c +++ qemud/remote.c 26 Jun 2007 09:50:53 -0000 @@ -460,6 +460,22 @@ remoteDispatchGetVersion (struct qemud_c } static int +remoteDispatchGetHostname (struct qemud_client *client, + remote_message_header *req, + void *args ATTRIBUTE_UNUSED, + remote_get_hostname_ret *ret) +{ + char *hostname; + CHECK_CONN(client); + + hostname = virConnectGetHostname (client->conn); + if (hostname == NULL) return -1; + + ret->hostname = hostname; + return 0; +} Index: qemud/remote_protocol.x =================================================================== RCS file: /data/cvs/libvirt/qemud/remote_protocol.x,v retrieving revision 1.2 diff -u -p -r1.2 remote_protocol.x --- qemud/remote_protocol.x 22 Jun 2007 13:16:10 -0000 1.2 +++ qemud/remote_protocol.x 26 Jun 2007 09:50:53 -0000 @@ -178,6 +178,10 @@ struct remote_get_version_ret { hyper hv_ver; }; +struct remote_get_hostname_ret { + remote_nonnull_string hostname; +}; + struct remote_get_max_vcpus_args { /* The only backend which supports this call is Xen HV, and * there the type is ignored so it could be NULL. @@ -605,7 +609,8 @@ enum remote_procedure { REMOTE_PROC_DOMAIN_SAVE = 55, REMOTE_PROC_DOMAIN_GET_SCHEDULER_TYPE = 56, REMOTE_PROC_DOMAIN_GET_SCHEDULER_PARAMETERS = 57, - REMOTE_PROC_DOMAIN_SET_SCHEDULER_PARAMETERS = 58 + REMOTE_PROC_DOMAIN_SET_SCHEDULER_PARAMETERS = 58, + REMOTE_PROC_GET_HOSTNAME = 59 };

@@ -1052,12 +1055,15 @@ static int qemuNetworkOpen(virConnectPtr static int qemuNetworkClose (virConnectPtr conn) { - qemuNetworkPrivatePtr netpriv = (qemuNetworkPrivatePtr) conn->networkPrivateData; - - if (!netpriv->shared) - close(netpriv->qemud_fd); - free(netpriv); - conn->networkPrivateData = NULL; + if (STRNEQ (conn->driver->name, "remote")) { + qemuNetworkPrivatePtr netpriv = + (qemuNetworkPrivatePtr) conn->networkPrivateData; + + if (!netpriv->shared) + close(netpriv->qemud_fd); + free(netpriv); + conn->networkPrivateData = NULL; + } return 0; }

diff -u -p -r1.7 remote_internal.c --- src/remote_internal.c 25 Jun 2007 13:05:03 -0000 1.7 +++ src/remote_internal.c 26 Jun 2007 09:50:59 -0000 @@ -58,6 +58,7 @@ struct private_data { gnutls_session_t session; /* GnuTLS session (if uses_tls != 0). */ char *type; /* Cached return from remoteType. */ int counter; /* Generates serial numbers for RPC. */ + char *uri; /* Original (remote) URI. */ };

+/* This call is unusual because it doesn't go over RPC. The + * full URI is known (only) at the client end of the connection. + */

+static char * +remoteGetURI (virConnectPtr conn) +{ + GET_PRIVATE (conn, NULL); + char *str; + + str = strdup (priv->uri); + if (str == NULL) { + error (conn, VIR_ERR_SYSTEM_ERROR, strerror (errno)); + return NULL; + } + return str; +} + #ifdef WITH_TEST

+ +#define _GNU_SOURCE /* for asprintf */ +

+ +char * +testGetURI (virConnectPtr conn) +{ + testPrivatePtr priv = (testPrivatePtr) conn->privateData; + char *uri; + + if (asprintf (&uri, "test://%s", priv->path) == -1) {

+ testError (conn, NULL, VIR_ERR_SYSTEM_ERROR, strerror (errno)); + return NULL; + } + return uri; +} + int testNodeGetInfo(virConnectPtr conn, virNodeInfoPtr info) {

@@ -129,13 +130,20 @@ xenUnifiedOpen (virConnectPtr conn, cons xmlFreeURI(uri); /* Allocate per-connection private data. */ - priv = malloc (sizeof *priv); + priv = calloc (1, sizeof *priv);

if (!priv) { xenUnifiedError (NULL, VIR_ERR_NO_MEMORY, "allocating private data"); return VIR_DRV_OPEN_ERROR; } conn->privateData = priv;

--- src/xen_unified.h 30 Apr 2007 16:57:15 -0000 1.3 +++ src/xen_unified.h 26 Jun 2007 09:51:05 -0000 @@ -50,6 +50,9 @@ struct _xenUnifiedPrivate { * xen_unified.c. */ int opened[XEN_UNIFIED_NR_DRIVERS]; + + /* Canonical URI. */ + char *name; };