Ensure a tls key is only generated once - wrap create & destroy in a mutex.

Change the function names to add _once to the tls_create & tls_destroy to
make this obvious.
Jeremy.

4 files changed, 71 insertions, 40 deletions

diff --git a/lib/util/smb_threads.c b/lib/util/smb_threads.c
index 8e0e1cd915..fa2d8da186 100644
--- a/lib/util/smb_threads.c
+++ b/lib/util/smb_threads.c
@@ -25,8 +25,6 @@
 
 #include "includes.h"
 
-#define NUM_GLOBAL_LOCKS 1
-
 /*********************************************************
  Functions to vector the locking primitives used internally
  by libsmbclient.
@@ -94,14 +92,18 @@ int smb_thread_set_functions(const struct smb_thread_functions *tf)
 
 SMB_THREADS_DEF_PTHREAD_IMPLEMENTATION(tf);
 
+void *pkey = NULL;
+
 /* Test function. */
 int test_threads(void)
 {
 	int ret;
 	void *plock = NULL;
-
 	smb_thread_set_functions(&tf);
 
+	if ((ret = SMB_THREAD_CREATE_TLS_ONCE("test_tls", pkey)) != 0) {
+		printf("Create tls once error: %d\n", ret);
+	}
 	if ((ret = SMB_THREAD_CREATE_MUTEX("test", plock)) != 0) {
 		printf("Create lock error: %d\n", ret);
 	}
@@ -112,6 +114,7 @@ int test_threads(void)
 		printf("unlock error: %d\n", ret);
 	}
 	SMB_THREAD_DESTROY_MUTEX(plock);
+	SMB_THREAD_DESTROY_TLS_ONCE(pkey);
 
 	return 0;
 }
diff --git a/lib/util/smb_threads.h b/lib/util/smb_threads.h
index 2ca163be9a..945e93803a 100644
--- a/lib/util/smb_threads.h
+++ b/lib/util/smb_threads.h
@@ -36,10 +36,10 @@ struct smb_thread_functions {
 			const char *location);
 
 	/* Thread local storage. */
-	int (*create_tls)(const char *keyname,
+	int (*create_tls_once)(const char *keyname,
 			void **ppkey,
 			const char *location);
-	void (*destroy_tls)(void *pkey,
+	void (*destroy_tls_once)(void **pkey,
 			const char *location);
 	int (*set_tls)(void *pkey, const void *pval, const char *location);
 	void *(*get_tls)(void *pkey, const char *location);
@@ -53,49 +53,69 @@ extern const struct smb_thread_functions *global_tfp;
  \
 static int smb_create_mutex_pthread(const char *lockname, void **pplock, const char *location) \
 { \
-        pthread_mutex_t *pmut = (pthread_mutex_t *)malloc(sizeof(pthread_mutex_t)); \
-        if (!pmut) { \
-                return ENOMEM; \
-        } \
-        pthread_mutex_init(pmut, NULL); \
-        *pplock = (void *)pmut; \
-        return 0; \
+	pthread_mutex_t *pmut = (pthread_mutex_t *)malloc(sizeof(pthread_mutex_t)); \
+	if (!pmut) { \
+		return ENOMEM; \
+	} \
+	pthread_mutex_init(pmut, NULL); \
+	*pplock = (void *)pmut; \
+	return 0; \
 } \
  \
 static void smb_destroy_mutex_pthread(void *plock, const char *location) \
 { \
-        pthread_mutex_destroy((pthread_mutex_t *)plock); \
+	pthread_mutex_destroy((pthread_mutex_t *)plock); \
 	free(plock); \
 } \
  \
 static int smb_lock_pthread(void *plock, enum smb_thread_lock_type lock_type, const char *location) \
 { \
-        if (lock_type == SMB_THREAD_UNLOCK) { \
-                return pthread_mutex_unlock((pthread_mutex_t *)plock); \
-        } else { \
-                return pthread_mutex_lock((pthread_mutex_t *)plock); \
-        } \
+	if (lock_type == SMB_THREAD_UNLOCK) { \
+		return pthread_mutex_unlock((pthread_mutex_t *)plock); \
+	} else { \
+		return pthread_mutex_lock((pthread_mutex_t *)plock); \
+	} \
 } \
  \
-static int smb_create_tls_pthread(const char *keyname, void **ppkey, const char *location) \
+static pthread_mutex_t create_tls_mutex = PTHREAD_MUTEX_INITIALIZER; \
+ \
+static int smb_create_tls_once_pthread(const char *keyname, void **ppkey, const char *location) \
 { \
-        int ret; \
-        pthread_key_t *pkey = (pthread_key_t *)malloc(sizeof(pthread_key_t)); \
-        if (!pkey) { \
-                return ENOMEM; \
-        } \
-        ret = pthread_key_create(pkey, NULL); \
-        if (ret) { \
-                return ret; \
-        } \
-        *ppkey = (void *)pkey; \
-        return 0; \
+	int ret; \
+	pthread_key_t *pkey; \
+	ret = pthread_mutex_lock(&create_tls_mutex); \
+	if (ret) { \
+		return ret; \
+	} \
+	if (*ppkey) { \
+		pthread_mutex_unlock(&create_tls_mutex); \
+		return 0; \
+	} \
+	pkey = (pthread_key_t *)malloc(sizeof(pthread_key_t)); \
+	if (!pkey) { \
+		pthread_mutex_unlock(&create_tls_mutex); \
+		return ENOMEM; \
+	} \
+	ret = pthread_key_create(pkey, NULL); \
+	if (ret) { \
+		free(pkey); \
+		pthread_mutex_unlock(&create_tls_mutex); \
+		return ret; \
+	} \
+	*ppkey = (void *)pkey; \
+	pthread_mutex_unlock(&create_tls_mutex); \
+	return 0; \
 } \
  \
-static void smb_destroy_tls_pthread(void *pkey, const char *location) \
+static void smb_destroy_tls_once_pthread(void **ppkey, const char *location) \
 { \
-        pthread_key_delete(*(pthread_key_t *)pkey); \
-        free(pkey); \
+	pthread_mutex_lock(&create_tls_mutex); \
+	if (*ppkey) { \
+		pthread_key_delete(*(pthread_key_t *)ppkey); \
+		free(*ppkey); \
+		*ppkey = NULL; \
+	} \
+	pthread_mutex_unlock(&create_tls_mutex); \
 } \
  \
 static int smb_set_tls_pthread(void *pkey, const void *pval, const char *location) \
@@ -112,8 +132,8 @@ static const struct smb_thread_functions (tf) = { \
                         smb_create_mutex_pthread, \
                         smb_destroy_mutex_pthread, \
                         smb_lock_pthread, \
-                        smb_create_tls_pthread, \
-                        smb_destroy_tls_pthread, \
+                        smb_create_tls_once_pthread, \
+                        smb_destroy_tls_once_pthread, \
                         smb_set_tls_pthread, \
                         smb_get_tls_pthread }
 
diff --git a/lib/util/smb_threads_internal.h b/lib/util/smb_threads_internal.h
index ad05aae9a5..58c6fe3f99 100644
--- a/lib/util/smb_threads_internal.h
+++ b/lib/util/smb_threads_internal.h
@@ -33,13 +33,13 @@
 #define SMB_THREAD_LOCK(plock, type) \
 	(global_tfp ? global_tfp->lock_mutex((plock), (type), __location__) : 0)
 
-#define SMB_THREAD_CREATE_TLS(keyname, key) \
-	(global_tfp ? global_tfp->create_tls((keyname), &(key), __location__) : 0)
+#define SMB_THREAD_CREATE_TLS_ONCE(keyname, key) \
+	(global_tfp ? global_tfp->create_tls_once((keyname), &(key), __location__) : 0)
 
-#define SMB_THREAD_DESTROY_TLS(key) \
+#define SMB_THREAD_DESTROY_TLS_ONCE(key) \
 	do { \
 		if (global_tfp) { \
-			global_tfp->destroy_tls(key); \
+			global_tfp->destroy_tls_once(&(key), __location__); \
 		}; \
 	} while (0)
 
@@ -50,4 +50,12 @@
 #define SMB_THREAD_GET_TLS(key) \
 	(global_tfp ? global_tfp->get_tls((key), __location__) : (key))
 
+/*
+ * Global thread lock list.
+ */
+
+#define NUM_GLOBAL_LOCKS 1
+
+#define GLOBAL_LOCK(locknum) (global_lock_array ? global_lock_array[(locknum)] : NULL)
+
 #endif
diff --git a/lib/util/talloc_stack.c b/lib/util/talloc_stack.c
index a9b6e033ce..f572dd6c77 100644
--- a/lib/util/talloc_stack.c
+++ b/lib/util/talloc_stack.c
@@ -74,7 +74,7 @@ static struct talloc_stackframe *talloc_stackframe_init(void)
 
 	ZERO_STRUCTP(ts);
 
-	if (SMB_THREAD_CREATE_TLS("talloc_stackframe", global_ts)) {
+	if (SMB_THREAD_CREATE_TLS_ONCE("talloc_stackframe", global_ts)) {
 		smb_panic("talloc_stackframe_init create_tls failed");
 	}