Add new "shell command" feature to Binder objects.

IBinder has a new common interface for sending shell commands
to it.  This can be implemented by system services to provide
a shell interface to the service, without needing to have separate
shell java code.

Also add a new "cmd" command line tool, which invokes the shell
command method on a system service.  This is much like dumpsys,
but for shell commands.

Change-Id: I95dc80c881a28cefb76957ad4d4fd9b3ed9630df
diff --git a/cmds/cmd/cmd.cpp b/cmds/cmd/cmd.cpp
new file mode 100644
index 0000000..01d0a47
--- /dev/null
+++ b/cmds/cmd/cmd.cpp
@@ -0,0 +1,95 @@
+/*
+ * Copyright (C) 2015 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.
+ */
+
+#define LOG_TAG "cmd"
+
+#include <utils/Log.h>
+#include <binder/Parcel.h>
+#include <binder/ProcessState.h>
+#include <binder/IResultReceiver.h>
+#include <binder/IServiceManager.h>
+#include <binder/TextOutput.h>
+#include <utils/Vector.h>
+
+#include <getopt.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/time.h>
+
+using namespace android;
+
+static int sort_func(const String16* lhs, const String16* rhs)
+{
+    return lhs->compare(*rhs);
+}
+
+class MyResultReceiver : public BnResultReceiver
+{
+public:
+    virtual void send(int32_t /*resultCode*/) {
+    }
+};
+
+int main(int argc, char* const argv[])
+{
+    signal(SIGPIPE, SIG_IGN);
+    sp<ProcessState> proc = ProcessState::self();
+    proc->startThreadPool();
+
+    sp<IServiceManager> sm = defaultServiceManager();
+    fflush(stdout);
+    if (sm == NULL) {
+        ALOGE("Unable to get default service manager!");
+        aerr << "cmd: Unable to get default service manager!" << endl;
+        return 20;
+    }
+
+    if (argc == 1) {
+        aout << "cmd: no service specified; use -l to list all services" << endl;
+        return 20;
+    }
+
+    if ((argc == 2) && (strcmp(argv[1], "-l") == 0)) {
+        Vector<String16> services = sm->listServices();
+        services.sort(sort_func);
+        aout << "Currently running services:" << endl;
+
+        for (size_t i=0; i<services.size(); i++) {
+            sp<IBinder> service = sm->checkService(services[i]);
+            if (service != NULL) {
+                aout << "  " << services[i] << endl;
+            }
+        }
+        return 0;
+    }
+
+    Vector<String16> args;
+    for (int i=2; i<argc; i++) {
+        args.add(String16(argv[i]));
+    }
+    String16 cmd = String16(argv[1]);
+    sp<IBinder> service = sm->checkService(cmd);
+    if (service == NULL) {
+        aerr << "Can't find service: " << argv[1] << endl;
+        return 20;
+    }
+
+    // TODO: block until a result is returned to MyResultReceiver.
+    service->shellCommand(STDIN_FILENO, STDOUT_FILENO, STDERR_FILENO, args, new MyResultReceiver());
+    return 0;
+}