Expose idmap

These might be important for users to know which uid/gid to use when
sharing data between host and container.

src/middlewared/middlewared/api/v25_04_0/virt_instance.py

@@ -37,6 +37,17 @@ class Image(BaseModel):
     variant: str | None
 
 
+class IdmapUserNsEntry(BaseModel):
+    hostid: int
+    maprange: int
+    nsid: int
+
+
+class UserNsIdmap(BaseModel):
+    uid: IdmapUserNsEntry
+    gid: IdmapUserNsEntry
+
+
 class VirtInstanceEntry(BaseModel):
     id: str
     name: Annotated[NonEmptyString, StringConstraints(max_length=200)]
@@ -48,6 +59,7 @@ class VirtInstanceEntry(BaseModel):
     environment: dict[str, str]
     aliases: list[VirtInstanceAlias]
     image: Image
+    userns_idmap: UserNsIdmap | None
     raw: dict | None
     vnc_enabled: bool
     vnc_port: int | None

src/middlewared/middlewared/plugins/virt/instance.py

@@ -80,6 +80,29 @@ async def query(self, filters, options):
                 'raw': None,  # Default required by pydantic
             }
 
+            idmap = None
+            if idmap_current := i['config'].get('volatile.idmap.current'):
+                idmap_current = json.loads(idmap_current)
+                uid = list(filter(lambda x: x.get('Isuid'), idmap_current)) or None
+                if uid:
+                    uid = {
+                        'hostid': uid[0]['Hostid'],
+                        'maprange': uid[0]['Maprange'],
+                        'nsid': uid[0]['Nsid'],
+                    }
+                gid = list(filter(lambda x: x.get('Isgid'), idmap_current)) or None
+                if gid:
+                    gid = {
+                        'hostid': gid[0]['Hostid'],
+                        'maprange': gid[0]['Maprange'],
+                        'nsid': gid[0]['Nsid'],
+                    }
+                idmap = {
+                    'uid': uid,
+                    'gid': gid,
+                }
+            entry['userns_idmap'] = idmap
+
             if options['extra'].get('raw'):
                 entry['raw'] = i