Set thread names to be visible in debuggers

base/threading/platform_thread_android.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/threading/platform_thread.h"
 
 #include <errno.h>
+#include <sys/prctl.h>
 #include <sys/resource.h>
 
 #include "base/android/jni_android.h"
 #include "base/android/thread_utils.h"
 #include "base/lazy_instance.h"
 #include "base/logging.h"
 #include "base/threading/thread_id_name_manager.h"
 #include "base/tracked_objects.h"
 #include "jni/ThreadUtils_jni.h"
 
@@ skipping 52 matching lines @@
   // granted permission to adjust nice values on the system.
   DCHECK_NE(handle.id_, kInvalidThreadId);
   int kNiceSetting = ThreadNiceValue(priority);
   if (setpriority(PRIO_PROCESS, handle.id_, kNiceSetting))
     LOG(ERROR) << "Failed to set nice value of thread to " << kNiceSetting;
 }
 
 void PlatformThread::SetName(const char* name) {
   ThreadIdNameManager::GetInstance()->SetName(CurrentId(), name);
   tracked_objects::ThreadData::InitializeThreadContext(name);
+
+  // Like linux, on android we can get the thread names to show up in the
+  // debugger by setting the process name for the LWP.
+  // We don't want to do this for the main thread because that would rename
+  // the process, causing tools like killall to stop working.
+  if (PlatformThread::CurrentId() == getpid())
+    return;
+
+  // Set the name for the LWP (which gets truncated to 15 characters).
+  int err = prctl(PR_SET_NAME, name);
+  if (err < 0 && errno != EPERM)
+    DPLOG(ERROR) << "prctl(PR_SET_NAME)";
 }
 
 
 void InitThreading() {
 }
 
 void InitOnThread() {
   // Threads on linux/android may inherit their priority from the thread
   // where they were created. This sets all new threads to the default.
   PlatformThread::SetThreadPriority(PlatformThread::CurrentHandle(),
@@ skipping 12 matching lines @@
   // 1Mb is not enough for some tests (see http://crbug.com/263749 for example).
   return 2 * (1 << 20);  // 2Mb
 #endif
 }
 
 bool RegisterThreadUtils(JNIEnv* env) {
   return RegisterNativesImpl(env);
 }
 
 }  // namespace base