libnetutils: Restore dhcptool

Despite it is not used for network management, it is
very convenient tool for wifi bringup and debugging.

Test: Manual

Change-Id: I045301acc2dd15d0e68d6b99c8e214865f19ebad
Signed-off-by: Dmitry Shmidt <dimitrysh@google.com>

libnetutils/Android.bp

@@ -17,3 +17,17 @@ cc_library_shared {
 
     export_include_dirs: ["include"],
 }
+
+cc_binary {
+    name: "dhcptool",
+
+    srcs: [
+        "dhcptool.c",
+    ],
+
+    shared_libs: [
+        "libnetutils",
+    ],
+
+    cflags: ["-Werror"],
+}

libnetutils/dhcptool.c

@@ -0,0 +1,47 @@
+/*
+ * Copyright 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.
+ */
+
+#include <err.h>
+#include <errno.h>
+#include <error.h>
+#include <stdbool.h>
+#include <stdlib.h>
+
+#include <netutils/ifc.h>
+
+extern int do_dhcp(char*);
+
+int main(int argc, char* argv[]) {
+    if (argc != 2) {
+        error(EXIT_FAILURE, 0, "usage: %s INTERFACE", argv[0]);
+    }
+
+    char* interface = argv[1];
+    if (ifc_init()) {
+        err(errno, "dhcptool %s: ifc_init failed", interface);
+        ifc_close();
+        return EXIT_FAILURE;
+    }
+
+    int rc = do_dhcp(interface);
+    if (rc) {
+        err(errno, "dhcptool %s: do_dhcp failed", interface);
+    }
+
+    ifc_close();
+
+    return rc ? EXIT_FAILURE : EXIT_SUCCESS;
+}