Make libpthread compatible with an ld.so that does TCB allocation:

if the initial thread already has a TCB then don't override it, and
if the _dl_allocate_tls() and _dl_free_tls() symbols exist then use
them instead of malloc/free

ok kettenis@

2 files changed, 47 insertions, 19 deletions

diff --git a/lib/librthread/rthread.c b/lib/librthread/rthread.c
index f19fc926d49..bbf68d521b2 100644
--- a/lib/librthread/rthread.c
+++ b/lib/librthread/rthread.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: rthread.c,v 1.66 2012/08/22 23:43:32 matthew Exp $ */
+/*	$OpenBSD: rthread.c,v 1.67 2013/02/14 03:38:15 guenther Exp $ */
 /*
  * Copyright (c) 2004,2005 Ted Unangst <tedu@openbsd.org>
  * All Rights Reserved.
@@ -47,6 +47,9 @@
 #include "rthread.h"
 #include "tcb.h"
 
+#pragma weak _dl_allocate_tls
+#pragma weak _dl_free_tls
+
 static int concurrency_level;	/* not used */
 
 int _threads_ready;
@@ -100,11 +103,20 @@ _spinunlock(_spinlock_lock_t *lock)
 void _rthread_initlib(void) __attribute__((constructor));
 void _rthread_initlib(void)
 {
-	struct thread_control_block *tcb = &_initial_thread_tcb;
+	struct thread_control_block *tcb = __get_tcb();
+ 
+	/*
+	 * A newer ld.so may provide a TCB allocation for us.
+	 * If not, use a static allocation
+	 */
+	if (tcb == NULL) {
+		tcb = &_initial_thread_tcb;
+		tcb->tcb_dtv = 0;
+		TCB_SET(tcb);
+	}
 
 	/* use libc's errno for the main thread */
 	TCB_INIT(tcb, &_initial_thread, ___errno());
-	TCB_SET(tcb);
 }
 
 int *
@@ -260,6 +272,30 @@ pthread_self(void)
 	return (TCB_THREAD());
 }
 
+static inline struct thread_control_block *
+allocate_tcb(void)
+{
+	struct thread_control_block *tcb;
+
+	if (&_dl_allocate_tls != 0)
+		tcb = _dl_allocate_tls(NULL);
+	else {
+		tcb = malloc(sizeof(*tcb));
+		tcb->tcb_dtv = 0;
+	}
+	return (tcb);
+}
+
+static inline void
+free_tcb(struct thread_control_block *tcb)
+{
+	if (&_dl_free_tls != 0)
+		_dl_free_tls(tcb);
+	else
+		free(tcb);
+}
+
+
 static void
 _rthread_reaper(void)
 {
@@ -275,8 +311,7 @@ restart:
 		_rthread_debug(3, "rthread reaping %p stack %p\n",
 		    (void *)thread, (void *)thread->stack);
 		_rthread_free_stack(thread->stack);
-		_rtld_free_tls(thread->arg,
-		    sizeof(struct thread_control_block), sizeof(void *));
+		free_tcb(thread->arg);
 		free(thread);
 		goto restart;
 	}
@@ -417,7 +452,7 @@ pthread_create(pthread_t *threadp, const pthread_attr_t *attr,
 		goto fail1;
 	}
 
-	tcb = _rtld_allocate_tls(NULL, sizeof(*tcb), sizeof(void *));
+	tcb = allocate_tcb();
 	if (tcb == NULL) {
 		rc = errno;
 		goto fail2;
@@ -446,7 +481,7 @@ pthread_create(pthread_t *threadp, const pthread_attr_t *attr,
 	_spinlock(&_thread_lock);
 	LIST_REMOVE(thread, threads);
 	_spinunlock(&_thread_lock);
-	_rtld_free_tls(tcb, sizeof(*tcb), sizeof(void *));
+	free_tcb(tcb);
 fail2:
 	_rthread_free_stack(thread->stack);
 fail1:
diff --git a/lib/librthread/tcb.h b/lib/librthread/tcb.h
index 43e2820e1e7..2139d21d6db 100644
--- a/lib/librthread/tcb.h
+++ b/lib/librthread/tcb.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: tcb.h,v 1.4 2012/02/18 21:43:28 fgsch Exp $	*/
+/*	$OpenBSD: tcb.h,v 1.5 2013/02/14 03:38:15 guenther Exp $	*/
 /*
  * Copyright (c) 2011 Philip Guenther <guenther@openbsd.org>
  *
@@ -85,7 +85,6 @@ struct thread_control_block {
 	__ERRNOPTR(TCB_THREAD())
 #define	TCB_INIT(tcb, thread, errnoptr)			\
 	do {						\
-		(tcb)->tcb_dtv = 0;			\
 		(tcb)->tcb_thread = (thread);		\
 		__ERRNOPTR(thread) = (errnoptr);	\
 	} while (0)
@@ -113,7 +112,6 @@ struct thread_control_block {
 #define	TCB_INIT(tcb, thread, errnoptr)			\
 	do {						\
 		(tcb)->__tcb_self = (tcb);		\
-		(tcb)->tcb_dtv = 0;			\
 		(tcb)->tcb_thread = (thread);		\
 		(tcb)->__tcb_errno = (errnoptr);	\
 	} while (0)
@@ -129,16 +127,11 @@ struct thread_control_block {
 #define	TCB_SET(tcb)	__set_tcb(tcb)
 #endif
 
-#if 0
-void *_rtld_allocate_tls(void *, size_t, size_t);
-void _rtld_free_tls(void *, size_t, size_t);
-#else
 /*
- * XXX Until we have these in ld.so and support __thread, just use
- * malloc/free.  The main thread's TCB cannot be allocated or freed with these.
+ * Functions that will eventually be provided by ld.so for allocating 
+ * and freeing TCBs
  */
-#define	_rtld_allocate_tls(old, size, align)	malloc(size)
-#define	_rtld_free_tls(old, size, align)	free(old)
-#endif
+void	*_dl_allocate_tls(void *);
+void	_dl_free_tls(void *);
 
 #endif /* _TCB_H_ */