Fix two issues related to thread private data in asr.

- setting up asr in single thread mode and then starting threads using asr
  would lead to multiple threads sharing the same resolver.
- destruction of a thread that has been using asr would leak data.
Problem originally reported by Alexey Sokolov and Uli Schlachter.
ok kettenis@

4 files changed, 49 insertions, 20 deletions

diff --git a/lib/libc/asr/asr.c b/lib/libc/asr/asr.c
index 8bc25fd82bd..c3e32228cd7 100644
--- a/lib/libc/asr/asr.c
+++ b/lib/libc/asr/asr.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: asr.c,v 1.64 2020/07/06 13:33:05 pirofti Exp $	*/
+/*	$OpenBSD: asr.c,v 1.65 2021/01/06 19:54:17 otto Exp $	*/
 /*
  * Copyright (c) 2010-2012 Eric Faurot <eric@openbsd.org>
  *
@@ -117,7 +117,7 @@ _asr_resolver_done(void *arg)
 		_asr_ctx_unref(ac);
 		return;
 	} else {
-		priv = _THREAD_PRIVATE(_asr, _asr, &_asr);
+		priv = _THREAD_PRIVATE_DT(_asr, _asr, NULL, &_asr);
 		if (*priv == NULL)
 			return;
 		asr = *priv;
@@ -128,6 +128,23 @@ _asr_resolver_done(void *arg)
 	free(asr);
 }
 
+static void
+_asr_resolver_done_tp(void *arg)
+{
+	char buf[100];
+	int len;
+	struct asr **priv = arg;
+	struct asr *asr;
+
+	if (*priv == NULL)
+		return;
+	asr = *priv;
+
+	_asr_ctx_unref(asr->a_ctx);
+	free(asr);
+	free(priv);
+}
+
 void *
 asr_resolver_from_string(const char *str)
 {
@@ -349,7 +366,8 @@ _asr_use_resolver(void *arg)
 	}
 	else {
 		DPRINT("using thread-local resolver\n");
-		priv = _THREAD_PRIVATE(_asr, _asr, &_asr);
+		priv = _THREAD_PRIVATE_DT(_asr, _asr, _asr_resolver_done_tp,
+		    &_asr);
 		if (*priv == NULL) {
 			DPRINT("setting up thread-local resolver\n");
 			*priv = _asr_resolver();
diff --git a/lib/libc/include/thread_private.h b/lib/libc/include/thread_private.h
index 98dfaa63223..237c3fbd034 100644
--- a/lib/libc/include/thread_private.h
+++ b/lib/libc/include/thread_private.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: thread_private.h,v 1.35 2019/02/13 13:22:14 mpi Exp $ */
+/* $OpenBSD: thread_private.h,v 1.36 2021/01/06 19:54:17 otto Exp $ */
 
 /* PUBLIC DOMAIN: No Rights Reserved. Marco S Hyman <marc@snafu.org> */
 
@@ -98,7 +98,8 @@ struct thread_callbacks {
 	void	(*tc_mutex_destroy)(void **);
 	void	(*tc_tag_lock)(void **);
 	void	(*tc_tag_unlock)(void **);
-	void	*(*tc_tag_storage)(void **, void *, size_t, void *);
+	void	*(*tc_tag_storage)(void **, void *, size_t, void (*)(void *),
+	   void *);
 	__pid_t	(*tc_fork)(void);
 	__pid_t	(*tc_vfork)(void);
 	void	(*tc_thread_release)(struct pthread *);
@@ -142,6 +143,7 @@ __END_HIDDEN_DECLS
 #define _THREAD_PRIVATE_MUTEX_LOCK(name)		do {} while (0)
 #define _THREAD_PRIVATE_MUTEX_UNLOCK(name)		do {} while (0)
 #define _THREAD_PRIVATE(keyname, storage, error)	&(storage)
+#define _THREAD_PRIVATE_DT(keyname, storage, dt, error)	&(storage)
 #define _MUTEX_LOCK(mutex)				do {} while (0)
 #define _MUTEX_UNLOCK(mutex)				do {} while (0)
 #define _MUTEX_DESTROY(mutex)				do {} while (0)
@@ -168,7 +170,12 @@ __END_HIDDEN_DECLS
 #define _THREAD_PRIVATE(keyname, storage, error)			\
 	(_thread_cb.tc_tag_storage == NULL ? &(storage) :		\
 	    _thread_cb.tc_tag_storage(&(__THREAD_NAME(keyname)),	\
-		&(storage), sizeof(storage), error))
+		&(storage), sizeof(storage), NULL, (error)))
+
+#define _THREAD_PRIVATE_DT(keyname, storage, dt, error)			\
+	(_thread_cb.tc_tag_storage == NULL ? &(storage) :		\
+	    _thread_cb.tc_tag_storage(&(__THREAD_NAME(keyname)),	\
+		&(storage), sizeof(storage), (dt), (error)))
 
 /*
  * Macros used in libc to access mutexes.
diff --git a/lib/libc/thread/rthread_cb.h b/lib/libc/thread/rthread_cb.h
index 3e8604c4ed4..d82c8b649e8 100644
--- a/lib/libc/thread/rthread_cb.h
+++ b/lib/libc/thread/rthread_cb.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: rthread_cb.h,v 1.2 2017/09/05 02:40:54 guenther Exp $ */
+/*	$OpenBSD: rthread_cb.h,v 1.3 2021/01/06 19:54:17 otto Exp $ */
 /*
  * Copyright (c) 2016 Philip Guenther <guenther@openbsd.org>
  * All Rights Reserved.
@@ -35,5 +35,5 @@ void	_thread_mutex_unlock(void **);
 void	_thread_mutex_destroy(void **);
 void	_thread_tag_lock(void **);
 void	_thread_tag_unlock(void **);
-void	*_thread_tag_storage(void **, void *, size_t, void *);
+void	*_thread_tag_storage(void **, void *, size_t, void (*)(void*), void *);
 __END_HIDDEN_DECLS
diff --git a/lib/libc/thread/rthread_libc.c b/lib/libc/thread/rthread_libc.c
index b99d6d19704..2a117c14f6e 100644
--- a/lib/libc/thread/rthread_libc.c
+++ b/lib/libc/thread/rthread_libc.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: rthread_libc.c,v 1.3 2019/01/10 18:45:33 otto Exp $ */
+/* $OpenBSD: rthread_libc.c,v 1.4 2021/01/06 19:54:17 otto Exp $ */
 
 /* PUBLIC DOMAIN: No Rights Reserved. Marco S Hyman <marc@snafu.org> */
 
@@ -31,7 +31,7 @@ static pthread_mutex_t	_thread_tag_mutex = PTHREAD_MUTEX_INITIALIZER;
  * This function will never return NULL.
  */
 static void
-_thread_tag_init(void **tag)
+_thread_tag_init(void **tag, void (*dt)(void *))
 {
 	struct _thread_tag *tt;
 	int result;
@@ -42,7 +42,8 @@ _thread_tag_init(void **tag)
 			tt = malloc(sizeof *tt);
 			if (tt != NULL) {
 				result = pthread_mutex_init(&tt->m, NULL);
-				result |= pthread_key_create(&tt->k, free);
+				result |= pthread_key_create(&tt->k, dt ? dt :
+				    free);
 				*tag = tt;
 			}
 		}
@@ -62,7 +63,7 @@ _thread_tag_lock(void **tag)
 
 	if (__isthreaded) {
 		if (*tag == NULL)
-			_thread_tag_init(tag);
+			_thread_tag_init(tag, NULL);
 		tt = *tag;
 		if (pthread_mutex_lock(&tt->m) != 0)
 			_rthread_debug(1, "tag mutex lock failure");
@@ -79,7 +80,7 @@ _thread_tag_unlock(void **tag)
 
 	if (__isthreaded) {
 		if (*tag == NULL)
-			_thread_tag_init(tag);
+			_thread_tag_init(tag, NULL);
 		tt = *tag;
 		if (pthread_mutex_unlock(&tt->m) != 0)
 			_rthread_debug(1, "tag mutex unlock failure");
@@ -88,28 +89,31 @@ _thread_tag_unlock(void **tag)
 
 /*
  * return the thread specific data for the given tag.   If there
- * is no data for this thread initialize it from 'storage'.
+ * is no data for this thread allocate and initialize it from 'storage'
+ * or clear it for non-main threads.
  * On any error return 'err'.
  */
 void *
-_thread_tag_storage(void **tag, void *storage, size_t sz, void *err)
+_thread_tag_storage(void **tag, void *storage, size_t sz, void (*dt)(void *),
+    void *err)
 {
 	struct _thread_tag *tt;
 	void *ret;
 
 	if (*tag == NULL)
-		_thread_tag_init(tag);
+		_thread_tag_init(tag, dt);
 	tt = *tag;
 
 	ret = pthread_getspecific(tt->k);
 	if (ret == NULL) {
-		ret = malloc(sz);
+		ret = calloc(1, sz);
 		if (ret == NULL)
 			ret = err;
 		else {
-			if (pthread_setspecific(tt->k, ret) == 0)
-				memcpy(ret, storage, sz);
-			else {
+			if (pthread_setspecific(tt->k, ret) == 0) {
+				if (pthread_self() == &_initial_thread)
+					memcpy(ret, storage, sz);
+			} else {
 				free(ret);
 				ret = err;
 			}