dumpsys: add --thread option

This displays the thread usage of services in the format
"<threadsUsed>/<threadCount>". This has been useful in lshal to find
deadlocks in binder threads.

Test: atest dumpsys_test
Test: run 'dumpsys --thread' on cuttlefish and verify thread usage
Test: run 'dumpsys --thread SurfaceFlinger' and verify thread usage
Bug: 140639610
Change-Id: I0cd3f86ca47ec911b276d8e8859ef54743ee34cf
diff --git a/cmds/dumpsys/dumpsys.cpp b/cmds/dumpsys/dumpsys.cpp
index a017246..ba1c449 100644
--- a/cmds/dumpsys/dumpsys.cpp
+++ b/cmds/dumpsys/dumpsys.cpp
@@ -25,6 +25,7 @@
 #include <binder/Parcel.h>
 #include <binder/ProcessState.h>
 #include <binder/TextOutput.h>
+#include <binderdebug/BinderDebug.h>
 #include <serviceutils/PriorityDumper.h>
 #include <utils/Log.h>
 #include <utils/Vector.h>
@@ -60,13 +61,15 @@
             "usage: dumpsys\n"
             "         To dump all services.\n"
             "or:\n"
-            "       dumpsys [-t TIMEOUT] [--priority LEVEL] [--pid] [--help | -l | --skip SERVICES "
+            "       dumpsys [-t TIMEOUT] [--priority LEVEL] [--pid] [--thread] [--help | -l | "
+            "--skip SERVICES "
             "| SERVICE [ARGS]]\n"
             "         --help: shows this help\n"
             "         -l: only list services, do not dump them\n"
             "         -t TIMEOUT_SEC: TIMEOUT to use in seconds instead of default 10 seconds\n"
             "         -T TIMEOUT_MS: TIMEOUT to use in milliseconds instead of default 10 seconds\n"
             "         --pid: dump PID instead of usual dump\n"
+            "         --thread: dump thread usage instead of usual dump\n"
             "         --proto: filter services that support dumping data in proto format. Dumps\n"
             "               will be in proto format.\n"
             "         --priority LEVEL: filter services based on specified priority\n"
@@ -125,7 +128,8 @@
     Type type = Type::DUMP;
     int timeoutArgMs = 10000;
     int priorityFlags = IServiceManager::DUMP_FLAG_PRIORITY_ALL;
-    static struct option longOptions[] = {{"pid", no_argument, 0, 0},
+    static struct option longOptions[] = {{"thread", no_argument, 0, 0},
+                                          {"pid", no_argument, 0, 0},
                                           {"priority", required_argument, 0, 0},
                                           {"proto", no_argument, 0, 0},
                                           {"skip", no_argument, 0, 0},
@@ -163,6 +167,8 @@
                 }
             } else if (!strcmp(longOptions[optionIndex].name, "pid")) {
                 type = Type::PID;
+            } else if (!strcmp(longOptions[optionIndex].name, "thread")) {
+                type = Type::THREAD;
             }
             break;
 
@@ -329,6 +335,23 @@
      return OK;
 }
 
+static status_t dumpThreadsToFd(const sp<IBinder>& service, const unique_fd& fd) {
+    pid_t pid;
+    status_t status = service->getDebugPid(&pid);
+    if (status != OK) {
+        return status;
+    }
+    BinderPidInfo pidInfo;
+    status = getBinderPidInfo(BinderDebugContext::BINDER, pid, &pidInfo);
+    if (status != OK) {
+        return status;
+    }
+    WriteStringToFd("Threads in use: " + std::to_string(pidInfo.threadUsage) + "/" +
+                        std::to_string(pidInfo.threadCount) + "\n",
+                    fd.get());
+    return OK;
+}
+
 status_t Dumpsys::startDumpThread(Type type, const String16& serviceName,
                                   const Vector<String16>& args) {
     sp<IBinder> service = sm_->checkService(serviceName);
@@ -359,6 +382,9 @@
         case Type::PID:
             err = dumpPidToFd(service, remote_end);
             break;
+        case Type::THREAD:
+            err = dumpThreadsToFd(service, remote_end);
+            break;
         default:
             std::cerr << "Unknown dump type" << static_cast<int>(type) << std::endl;
             return;