Adding Public Get and Set APIs for Network Metadata

This patch introduces public Get and Set APIs for modifying <title>,
<description> and <metadata> elements of the Network object.

- Added enum virNetworkMetadataType to select one of the above
  elements to operate on.
- Added error code and messages for missing metadata.
- Added public API implementation.
- Added driver support.

Signed-off-by: K Shiva Kiran <shiva_kr@riseup.net>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>

include/libvirt/libvirt-network.h

@@ -547,4 +547,33 @@ virNetworkPortFree(virNetworkPortPtr port);
 int
 virNetworkPortRef(virNetworkPortPtr port);
 
+/**
+ * virNetworkMetadataType:
+ *
+ * Since: 9.7.0
+ */
+typedef enum {
+    VIR_NETWORK_METADATA_DESCRIPTION = 0, /* Operate on <description> (Since: 9.7.0) */
+    VIR_NETWORK_METADATA_TITLE       = 1, /* Operate on <title> (Since: 9.7.0) */
+    VIR_NETWORK_METADATA_ELEMENT     = 2, /* Operate on <metadata> (Since: 9.7.0) */
+
+# ifdef VIR_ENUM_SENTINELS
+    VIR_NETWORK_METADATA_LAST /* (Since: 9.7.0) */
+# endif
+} virNetworkMetadataType;
+
+int
+virNetworkSetMetadata(virNetworkPtr network,
+                      int type,
+                      const char *metadata,
+                      const char *key,
+                      const char *uri,
+                      unsigned int flags);
+
+char *
+virNetworkGetMetadata(virNetworkPtr network,
+                      int type,
+                      const char *uri,
+                      unsigned int flags);
+
 #endif /* LIBVIRT_NETWORK_H */

include/libvirt/virterror.h

@@ -348,6 +348,7 @@ typedef enum {
     VIR_ERR_NO_HOSTNAME = 108,          /* no domain's hostname found (Since: 6.1.0) */
     VIR_ERR_CHECKPOINT_INCONSISTENT = 109, /* checkpoint can't be used (Since: 6.10.0) */
     VIR_ERR_MULTIPLE_DOMAINS = 110,     /* more than one matching domain found (Since: 7.1.0) */
+    VIR_ERR_NO_NETWORK_METADATA = 111,  /* Network metadata is not present (Since: 9.7.0) */
 
 # ifdef VIR_ENUM_SENTINELS
     VIR_ERR_NUMBER_LAST /* (Since: 5.0.0) */

src/driver-network.h

@@ -161,6 +161,20 @@ typedef int
                              virNetworkPortPtr **ports,
                              unsigned int flags);
 
+typedef int
+(*virDrvNetworkSetMetadata)(virNetworkPtr network,
+                            int type,
+                            const char *metadata,
+                            const char *key,
+                            const char *uri,
+                            unsigned int flags);
+
+typedef char *
+(*virDrvNetworkGetMetadata)(virNetworkPtr network,
+                            int type,
+                            const char *uri,
+                            unsigned int flags);
+
 typedef struct _virNetworkDriver virNetworkDriver;
 
 /**
@@ -202,4 +216,6 @@ struct _virNetworkDriver {
     virDrvNetworkPortGetParameters networkPortGetParameters;
     virDrvNetworkPortDelete networkPortDelete;
     virDrvNetworkListAllPorts networkListAllPorts;
+    virDrvNetworkSetMetadata networkSetMetadata;
+    virDrvNetworkGetMetadata networkGetMetadata;
 };

src/libvirt-network.c

@@ -1915,3 +1915,170 @@ virNetworkPortRef(virNetworkPortPtr port)
     virObjectRef(port);
     return 0;
 }
+
+
+/**
+ * virNetworkSetMetadata:
+ * @network: a network object
+ * @type: type of metadata, from virNetworkMetadataType
+ * @metadata: new metadata text
+ * @key: XML namespace key, or NULL
+ * @uri: XML namespace URI, or NULL
+ * @flags: bitwise-OR of virNetworkUpdateFlags
+ *
+ * Sets the appropriate network element given by @type to the
+ * value of @metadata.  A @type of VIR_NETWORK_METADATA_DESCRIPTION
+ * is free-form text; VIR_NETWORK_METADATA_TITLE is free-form, but no
+ * newlines are permitted, and should be short (although the length is
+ * not enforced). For these two options @key and @uri are irrelevant and
+ * must be set to NULL.
+ *
+ * For type VIR_NETWORK_METADATA_ELEMENT @metadata must be well-formed
+ * XML belonging to namespace defined by @uri with local name @key.
+ *
+ * Passing NULL for @metadata says to remove that element from the
+ * network XML (passing the empty string leaves the element present).
+ *
+ * The resulting metadata will be present in virNetworkGetXMLDesc(),
+ * as well as quick access through virNetworkGetMetadata().
+ *
+ * @flags controls whether the live network state, persistent configuration,
+ * or both will be modified.
+ *
+ * Returns 0 on success, -1 in case of failure.
+ *
+ * Since: 9.7.0
+ */
+int
+virNetworkSetMetadata(virNetworkPtr network,
+                      int type,
+                      const char *metadata,
+                      const char *key,
+                      const char *uri,
+                      unsigned int flags)
+{
+    virConnectPtr conn;
+
+    VIR_DEBUG("network=%p, type=%d, metadata='%s', key='%s', uri='%s', flags=0x%x",
+              network, type, NULLSTR(metadata), NULLSTR(key), NULLSTR(uri),
+              flags);
+
+    virResetLastError();
+
+    virCheckNetworkReturn(network, -1);
+    conn = network->conn;
+
+    virCheckReadOnlyGoto(conn->flags, error);
+
+    switch (type) {
+    case VIR_NETWORK_METADATA_TITLE:
+        if (metadata && strchr(metadata, '\n')) {
+            virReportInvalidArg(metadata, "%s",
+                                _("metadata title can't contain "
+                                  "newlines"));
+            goto error;
+        }
+        G_GNUC_FALLTHROUGH;
+    case VIR_NETWORK_METADATA_DESCRIPTION:
+        virCheckNullArgGoto(uri, error);
+        virCheckNullArgGoto(key, error);
+        break;
+    case VIR_NETWORK_METADATA_ELEMENT:
+        virCheckNonNullArgGoto(uri, error);
+        if (metadata)
+            virCheckNonNullArgGoto(key, error);
+        break;
+    default:
+        /* For future expansion */
+        break;
+    }
+
+    if (conn->networkDriver->networkSetMetadata) {
+        int ret;
+        ret = conn->networkDriver->networkSetMetadata(network, type, metadata, key, uri,
+                                                      flags);
+        if (ret < 0)
+            goto error;
+        return ret;
+    }
+
+    virReportUnsupportedError();
+
+ error:
+    virDispatchError(network->conn);
+    return -1;
+}
+
+
+/**
+ * virNetworkGetMetadata:
+ * @network: a network object
+ * @type: type of metadata, from virNetworkMetadataType
+ * @uri: XML namespace identifier
+ * @flags: bitwise-OR of virNetworkUpdateFlags
+ *
+ * Retrieves the appropriate network element given by @type.
+ * If VIR_NETWORK_METADATA_ELEMENT is requested parameter @uri
+ * must be set to the name of the namespace the requested elements
+ * belong to, otherwise must be NULL.
+ *
+ * If an element of the network XML is not present, the resulting
+ * error will be VIR_ERR_NO_NETWORK_METADATA.  This method forms
+ * a shortcut for seeing information from virNetworkSetMetadata()
+ * without having to go through virNetworkGetXMLDesc().
+ *
+ * @flags controls whether the live network state or persistent
+ * configuration will be queried.
+ *
+ * Returns the metadata string on success (caller must free),
+ * or NULL in case of failure.
+ *
+ * Since: 9.7.0
+ */
+char *
+virNetworkGetMetadata(virNetworkPtr network,
+                      int type,
+                      const char *uri,
+                      unsigned int flags)
+{
+    virConnectPtr conn;
+
+    VIR_DEBUG("network=%p, type=%d, uri='%s', flags=0x%x",
+               network, type, NULLSTR(uri), flags);
+
+    virResetLastError();
+
+    virCheckNetworkReturn(network, NULL);
+
+    VIR_EXCLUSIVE_FLAGS_GOTO(VIR_NETWORK_UPDATE_AFFECT_LIVE,
+                             VIR_NETWORK_UPDATE_AFFECT_CONFIG,
+                             error);
+
+    switch (type) {
+    case VIR_NETWORK_METADATA_TITLE:
+    case VIR_NETWORK_METADATA_DESCRIPTION:
+        virCheckNullArgGoto(uri, error);
+        break;
+    case VIR_NETWORK_METADATA_ELEMENT:
+        virCheckNonNullArgGoto(uri, error);
+        break;
+    default:
+        /* For future expansion */
+        break;
+    }
+
+    conn = network->conn;
+
+    if (conn->networkDriver->networkGetMetadata) {
+        char *ret;
+        if (!(ret = conn->networkDriver->networkGetMetadata(network, type, uri, flags)))
+            goto error;
+        return ret;
+    }
+
+    virReportUnsupportedError();
+
+ error:
+    virDispatchError(network->conn);
+    return NULL;
+}

src/libvirt_public.syms

@@ -932,4 +932,10 @@ LIBVIRT_9.0.0 {
         virDomainFDAssociate;
 } LIBVIRT_8.5.0;
 
+LIBVIRT_9.7.0 {
+    global:
+        virNetworkGetMetadata;
+        virNetworkSetMetadata;
+} LIBVIRT_9.0.0;
+
 # .... define new API here using predicted next version number ....

src/util/virerror.c

@@ -1287,6 +1287,9 @@ static const virErrorMsgTuple virErrorMsgStrings[] = {
     [VIR_ERR_MULTIPLE_DOMAINS] = {
         N_("multiple matching domains found"),
         N_("multiple matching domains found: %1$s") },
+    [VIR_ERR_NO_NETWORK_METADATA] = {
+        N_("metadata not found"),
+        N_("metadata not found: %1$s") },
 };
 
 G_STATIC_ASSERT(G_N_ELEMENTS(virErrorMsgStrings) == VIR_ERR_NUMBER_LAST);