pthread: remove 'pthread_attr' from pthread class

issue #2791
pthread_attr is not associated with any thread, the statistics must be
gathered at runtime, while 'pthread_attr_get_np' may retrieve attributes
by from any thread. Addtionally, the attributes given to
'pthread_create' will most likely be deleted after the creation call.

repos/libports/src/lib/pthread/thread.cc

@@ -22,6 +22,8 @@
 #include <stdlib.h> /* malloc, free */
 #include "thread.h"
 
+#include <libc/task.h> /* libc suspend/resume */
+
 using namespace Genode;
 
 /*
@@ -60,6 +62,22 @@ static __attribute__((constructor)) Thread * main_thread()
 }
 
 
+/*
+ * pthread
+ */
+void pthread::Thread_object::entry()
+{
+	void *exit_status = _start_routine(_arg);
+	_exiting = true;
+	Libc::resume_all();
+	pthread_exit(exit_status);
+}
+
+
+/*
+ * Registry
+ */
+
 void Pthread_registry::insert(pthread_t thread)
 {
 	/* prevent multiple insertions at the same location */
@@ -226,8 +244,7 @@ extern "C" {
 		 * of the pthread object would also destruct the 'Thread' of the main
 		 * thread.
 		 */
-		static pthread_attr main_thread_attr;
-		static pthread *main = new pthread(*Thread::myself(), &main_thread_attr);
+		static pthread *main = new pthread(*Thread::myself());
 		return main;
 	}
 
@@ -276,7 +293,7 @@ extern "C" {
 		if (!attr)
 			return EINVAL;
 
-		*attr = pthread->attr();
+		(*attr)->pthread = pthread;
 		return 0;
 	}
 

repos/libports/src/lib/pthread/thread.h

@@ -20,7 +20,6 @@
 #include <util/reconstructible.h>
 
 #include <pthread.h>
-#include <libc/task.h>
 
 /*
  * Used by 'pthread_self()' to find out if the current thread is an alien
@@ -119,13 +118,7 @@ struct pthread : Genode::Noncopyable, Genode::Thread::Tls::Base
 				_start_routine(start_routine), _arg(arg)
 			{ }
 
-			void entry() override
-			{
-				void *exit_status = _start_routine(_arg);
-				_exiting = true;
-				Libc::resume_all();
-				pthread_exit(exit_status);
-			}
+			void entry() override;
 		};
 
 		Genode::Constructible<Thread_object> _thread_object;
@@ -145,15 +138,9 @@ struct pthread : Genode::Noncopyable, Genode::Thread::Tls::Base
 		 */
 		Genode::Thread &_thread;
 
-		pthread_attr_t _attr;
-
 		void _associate_thread_with_pthread()
 		{
-			if (_attr)
-				_attr->pthread = this;
-
 			Genode::Thread::Tls::Base::tls(_thread, *this);
-
 			pthread_registry().insert(this);
 		}
 
@@ -162,13 +149,12 @@ struct pthread : Genode::Noncopyable, Genode::Thread::Tls::Base
 		/**
 		 * Constructor for threads created via 'pthread_create'
 		 */
-		pthread(pthread_attr_t attr, start_routine_t start_routine,
+		pthread(start_routine_t start_routine,
 		        void *arg, size_t stack_size, char const * name,
 		        Genode::Cpu_session * cpu, Genode::Affinity::Location location)
 		:
 			_thread(_construct_thread_object(name, stack_size, cpu, location,
-			                                 start_routine, arg)),
-			_attr(attr)
+			                                 start_routine, arg))
 		{
 			_associate_thread_with_pthread();
 		}
@@ -177,10 +163,9 @@ struct pthread : Genode::Noncopyable, Genode::Thread::Tls::Base
 		 * Constructor to create pthread object out of existing thread,
 		 * i.e., the main thread
 		 */
-		pthread(Genode::Thread &existing_thread, pthread_attr_t attr)
+		pthread(Genode::Thread &existing_thread)
 		:
-			_thread(existing_thread),
-			_attr(attr)
+			_thread(existing_thread)
 		{
 			_associate_thread_with_pthread();
 		}
@@ -200,8 +185,6 @@ struct pthread : Genode::Noncopyable, Genode::Thread::Tls::Base
 
 		void *stack_top()  const { return _thread.stack_top();  }
 		void *stack_base() const { return _thread.stack_base(); }
-
-		pthread_attr_t attr() { return _attr; }
 };
 
 #endif /* _INCLUDE__SRC_LIB_PTHREAD_THREAD_H_ */

repos/libports/src/lib/pthread/thread_create.cc

@@ -33,9 +33,9 @@ extern "C"
 		size_t const stack_size = (attr && *attr && (*attr)->stack_size)
 		                        ? (*attr)->stack_size : STACK_SIZE;
 
-		pthread_t thread_obj = new pthread(attr ? *attr : 0, start_routine,
-		                           arg, stack_size, "pthread", nullptr,
-		                           Genode::Affinity::Location());
+		pthread_t thread_obj = new pthread(start_routine, arg, stack_size,
+		                                   "pthread", nullptr,
+		                                   Genode::Affinity::Location());
 
 		if (!thread_obj)
 			return EAGAIN;