1 files changed, 131 insertions, 0 deletions
diff --git a/java/com/google/gerrit/sshd/AliasCommand.java b/java/com/google/gerrit/sshd/AliasCommand.java
new file mode 100644
index 0000000000..567cf00735
--- /dev/null
+++ b/java/com/google/gerrit/sshd/AliasCommand.java
@@ -0,0 +1,131 @@
+// Copyright (C) 2012 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.sshd;
+
+import com.google.common.base.Throwables;
+import com.google.common.util.concurrent.Atomics;
+import com.google.gerrit.extensions.api.access.GlobalOrPluginPermission;
+import com.google.gerrit.extensions.restapi.AuthException;
+import com.google.gerrit.server.permissions.GlobalPermission;
+import com.google.gerrit.server.permissions.PermissionBackend;
+import com.google.gerrit.server.permissions.PermissionBackendException;
+import java.io.IOException;
+import java.util.LinkedList;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.atomic.AtomicReference;
+import org.apache.sshd.server.Environment;
+import org.apache.sshd.server.command.Command;
+
+/** Command that executes some other command. */
+public class AliasCommand extends BaseCommand {
+  private final DispatchCommandProvider root;
+  private final PermissionBackend permissionBackend;
+  private final CommandName command;
+  private final AtomicReference<Command> atomicCmd;
+
+  AliasCommand(
+      @CommandName(Commands.ROOT) DispatchCommandProvider root,
+      PermissionBackend permissionBackend,
+      CommandName command) {
+    this.root = root;
+    this.permissionBackend = permissionBackend;
+    this.command = command;
+    this.atomicCmd = Atomics.newReference();
+  }
+
+  @Override
+  public void start(Environment env) throws IOException {
+    try {
+      begin(env);
+    } catch (Failure e) {
+      String msg = e.getMessage();
+      if (!msg.endsWith("\n")) {
+        msg += "\n";
+      }
+      err.write(msg.getBytes(ENC));
+      err.flush();
+      onExit(e.exitCode);
+    }
+  }
+
+  private void begin(Environment env) throws IOException, Failure {
+    Map<String, CommandProvider> map = root.getMap();
+    for (String name : chain(command)) {
+      CommandProvider p = map.get(name);
+      if (p == null) {
+        throw die(getName() + ": not found");
+      }
+
+      Command cmd = p.getProvider().get();
+      if (!(cmd instanceof DispatchCommand)) {
+        throw die(getName() + ": not found");
+      }
+      map = ((DispatchCommand) cmd).getMap();
+    }
+
+    CommandProvider p = map.get(command.value());
+    if (p == null) {
+      throw die(getName() + ": not found");
+    }
+
+    Command cmd = p.getProvider().get();
+    checkRequiresCapability(cmd);
+    if (cmd instanceof BaseCommand) {
+      BaseCommand bc = (BaseCommand) cmd;
+      bc.setName(getName());
+      bc.setArguments(getArguments());
+    }
+    provideStateTo(cmd);
+    atomicCmd.set(cmd);
+    cmd.start(env);
+  }
+
+  @Override
+  public void destroy() {
+    Command cmd = atomicCmd.getAndSet(null);
+    if (cmd != null) {
+      try {
+        cmd.destroy();
+      } catch (Exception e) {
+        Throwables.throwIfUnchecked(e);
+        throw new RuntimeException(e);
+      }
+    }
+  }
+
+  private void checkRequiresCapability(Command cmd) throws Failure {
+    try {
+      Set<GlobalOrPluginPermission> check = GlobalPermission.fromAnnotation(cmd.getClass());
+      try {
+        permissionBackend.currentUser().checkAny(check);
+      } catch (AuthException err) {
+        throw new UnloggedFailure(BaseCommand.STATUS_NOT_ADMIN, "fatal: " + err.getMessage());
+      }
+    } catch (PermissionBackendException err) {
+      throw new Failure(1, "fatal: permissions unavailable", err);
+    }
+  }
+
+  private static LinkedList<String> chain(CommandName command) {
+    LinkedList<String> chain = new LinkedList<>();
+    while (command != null) {
+      chain.addFirst(command.value());
+      command = Commands.parentOf(command);
+    }
+    chain.removeLast();
+    return chain;
+  }
+}