DO NOT MERGE: Add socket communication between recovery and minadbd

This cl adds a socket pair to support the communication between recovery
and minadbd. Therefore, minadbd will be able to issue multiple commands
to recovery and get back the status of each command.

This cl also switches the adb sideload from the recovery menu to use
this protocol; and moves minadbd to a separate binary.

Bug: 130166585
Test: sideload a package
Change-Id: I80d36d5c4e6fe1ae3ea23640907bc50c0dc0d482
(cherry picked from commit 34690ced91e22f5d9b5dd19c33b11c8e0b4bafa0)
diff --git a/minadbd/minadbd.cpp b/minadbd/minadbd.cpp
index 349189c..57158ad 100644
--- a/minadbd/minadbd.cpp
+++ b/minadbd/minadbd.cpp
@@ -14,30 +14,54 @@
  * limitations under the License.
  */
 
-#include "minadbd.h"
-
 #include <errno.h>
+#include <fcntl.h>
 #include <signal.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <strings.h>
+
+#include <android-base/logging.h>
+#include <android-base/parseint.h>
 
 #include "adb.h"
 #include "adb_auth.h"
 #include "transport.h"
 
-int minadbd_main() {
-    adb_device_banner = "sideload";
+#include "minadbd_services.h"
+#include "minadbd_types.h"
 
-    signal(SIGPIPE, SIG_IGN);
+int main(int argc, char** argv) {
+  android::base::InitLogging(argv, &android::base::StderrLogger);
+  // TODO(xunchang) implement a command parser
+  if (argc != 3 || strcmp("--socket_fd", argv[1]) != 0) {
+    LOG(ERROR) << "minadbd has invalid arguments, argc: " << argc;
+    exit(kMinadbdArgumentsParsingError);
+  }
 
-    // We can't require authentication for sideloading. http://b/22025550.
-    auth_required = false;
+  int socket_fd;
+  if (!android::base::ParseInt(argv[2], &socket_fd)) {
+    LOG(ERROR) << "Failed to parse int in " << argv[2];
+    exit(kMinadbdArgumentsParsingError);
+  }
+  if (fcntl(socket_fd, F_GETFD, 0) == -1) {
+    PLOG(ERROR) << "Failed to get minadbd socket";
+    exit(kMinadbdSocketIOError);
+  }
+  SetMinadbdSocketFd(socket_fd);
 
-    init_transport_registration();
-    usb_init();
+  adb_device_banner = "sideload";
 
-    VLOG(ADB) << "Event loop starting";
-    fdevent_loop();
+  signal(SIGPIPE, SIG_IGN);
 
-    return 0;
+  // We can't require authentication for sideloading. http://b/22025550.
+  auth_required = false;
+
+  init_transport_registration();
+  usb_init();
+
+  VLOG(ADB) << "Event loop starting";
+  fdevent_loop();
+
+  return 0;
 }