From 4d71c96fdcb71657dde4780693f3646a41cf5343 Mon Sep 17 00:00:00 2001
From: Jonas 'Sortie' Termansen <sortie@maxsi.org>
Date: Fri, 10 Jan 2014 16:01:28 +0100
Subject: [PATCH] Add pthread_once(3).

---
 libpthread/Makefile             |  1 +
 libpthread/include/__/pthread.h | 14 ++++++++++-
 libpthread/include/pthread.h    |  5 ++--
 libpthread/pthread_once.c++     | 42 +++++++++++++++++++++++++++++++++
 4 files changed, 59 insertions(+), 3 deletions(-)
 create mode 100644 libpthread/pthread_once.c++

diff --git a/libpthread/Makefile b/libpthread/Makefile
index a9b3316e..2f63fe21 100644
--- a/libpthread/Makefile
+++ b/libpthread/Makefile
@@ -36,6 +36,7 @@ pthread_mutex_init.o \
 pthread_mutex_lock.o \
 pthread_mutex_trylock.o \
 pthread_mutex_unlock.o \
+pthread_once.o \
 pthread_rwlock_destroy.o \
 pthread_rwlock_init.o \
 pthread_rwlock_rdlock.o \
diff --git a/libpthread/include/__/pthread.h b/libpthread/include/__/pthread.h
index 608e47a4..85ebafb4 100644
--- a/libpthread/include/__/pthread.h
+++ b/libpthread/include/__/pthread.h
@@ -99,7 +99,19 @@ typedef struct
 } __pthread_mutexattr_t;
 #endif
 
-typedef int __pthread_once_t;
+#if defined(__is_sortix_libpthread)
+typedef struct
+{
+	__pthread_mutex_t lock;
+	int executed;
+} __pthread_once_t;
+#else
+typedef struct
+{
+	__pthread_mutex_t __pthread_lock;
+	int __pthread_executed;
+} __pthread_once_t;
+#endif
 
 #if defined(__is_sortix_libpthread)
 typedef struct
diff --git a/libpthread/include/pthread.h b/libpthread/include/pthread.h
index d046bc75..56ba4e48 100644
--- a/libpthread/include/pthread.h
+++ b/libpthread/include/pthread.h
@@ -61,7 +61,6 @@ __BEGIN_DECLS
 #define PTHREAD_MUTEX_RECURSIVE 1
 /* TODO: #define PTHREAD_MUTEX_ROBUST */
 /* TODO: #define PTHREAD_MUTEX_STALLED */
-/* TODO: #define PTHREAD_ONCE_INIT */
 /* TODO: #define PTHREAD_PRIO_INHERIT */
 /* TODO: #define PTHREAD_PRIO_NONE */
 /* TODO: #define PTHREAD_PRIO_PROTECT */
@@ -161,6 +160,8 @@ struct pthread_cond_elem
 #define PTHREAD_NORMAL_MUTEX_INITIALIZER_NP { 0, PTHREAD_MUTEX_NORMAL, 0, 0 }
 #define PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP { 0, PTHREAD_MUTEX_RECURSIVE, 0, 0 }
 
+#define PTHREAD_ONCE_INIT { PTHREAD_NORMAL_MUTEX_INITIALIZER_NP, 0 }
+
 void pthread_initialize(void);
 
 #if defined(__is_sortix_libpthread)
@@ -256,7 +257,7 @@ int pthread_mutexattr_init(pthread_mutexattr_t*);
 /* TODO: pthread_mutexattr_setpshared */
 /* TODO: pthread_mutexattr_setrobust */
 int pthread_mutexattr_settype(pthread_mutexattr_t*, int);
-/* TODO: pthread_once */
+int pthread_once(pthread_once_t*, void (*)(void));
 int pthread_rwlock_destroy(pthread_rwlock_t*);
 int pthread_rwlock_init(pthread_rwlock_t* __restrict,
                         const pthread_rwlockattr_t* __restrict);
diff --git a/libpthread/pthread_once.c++ b/libpthread/pthread_once.c++
new file mode 100644
index 00000000..f8bb10cd
--- /dev/null
+++ b/libpthread/pthread_once.c++
@@ -0,0 +1,42 @@
+/*******************************************************************************
+
+    Copyright(C) Jonas 'Sortie' Termansen 2014.
+
+    This file is part of Sortix libpthread.
+
+    Sortix libpthread is free software: you can redistribute it and/or modify it
+    under the terms of the GNU Lesser General Public License as published by the
+    Free Software Foundation, either version 3 of the License, or (at your
+    option) any later version.
+
+    Sortix libpthread is distributed in the hope that it will be useful, but
+    WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+    or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
+    License for more details.
+
+    You should have received a copy of the GNU Lesser General Public License
+    along with Sortix libpthread. If not, see <http://www.gnu.org/licenses/>.
+
+    pthread_once.c++
+    Dynamic package initialization.
+
+*******************************************************************************/
+
+#include <pthread.h>
+
+extern "C"
+int pthread_once(pthread_once_t* once_control, void (*init_routine)(void))
+{
+	pthread_mutex_lock(&once_control->lock);
+	if ( !once_control->executed )
+	{
+		// TODO: If this thread is a cancellation point and is canceled, we must
+		//       pretend this pthread_once was never called. This means that we
+		//       need to ensure that once_control->lock is unlocked in the event
+		//       of a cancellation.
+		init_routine();
+		once_control->executed = 1;
+	}
+	pthread_mutex_unlock(&once_control->lock);
+	return 0;
+}