erts: Add enif_select & enif_open_resource_type_x

14 files changed, 1076 insertions, 107 deletions

diff --git a/erts/emulator/beam/erl_alloc.c b/erts/emulator/beam/erl_alloc.c
index 40a45c961f..3ddf7a53e2 100644
--- a/erts/emulator/beam/erl_alloc.c
+++ b/erts/emulator/beam/erl_alloc.c
@@ -663,6 +663,8 @@ erts_alloc_init(int *argc, char **argv, ErtsAllocInitOpts *eaiop)
 	= sizeof(ErtsDrvEventDataState);
     fix_type_sizes[ERTS_ALC_FIX_TYPE_IX(ERTS_ALC_T_DRV_SEL_D_STATE)]
 	= sizeof(ErtsDrvSelectDataState);
+    fix_type_sizes[ERTS_ALC_FIX_TYPE_IX(ERTS_ALC_T_NIF_SEL_D_STATE)]
+        = sizeof(ErtsNifSelectDataState);
     fix_type_sizes[ERTS_ALC_FIX_TYPE_IX(ERTS_ALC_T_MSG_REF)]
 	= sizeof(ErtsMessageRef);
 #ifdef ERTS_SMP
diff --git a/erts/emulator/beam/erl_alloc.types b/erts/emulator/beam/erl_alloc.types
index 6e8710eb8a..7ea8c98008 100644
--- a/erts/emulator/beam/erl_alloc.types
+++ b/erts/emulator/beam/erl_alloc.types
@@ -396,6 +396,7 @@ type	DRV_TAB		LONG_LIVED	SYSTEM		drv_tab
 type	DRV_EV_STATE	LONG_LIVED	SYSTEM		driver_event_state
 type	DRV_EV_D_STATE	FIXED_SIZE	SYSTEM		driver_event_data_state
 type	DRV_SEL_D_STATE	FIXED_SIZE	SYSTEM		driver_select_data_state
+type	NIF_SEL_D_STATE	FIXED_SIZE	SYSTEM		enif_select_data_state
 type	FD_LIST		SHORT_LIVED	SYSTEM		fd_list
 type	ACTIVE_FD_ARR	SHORT_LIVED	SYSTEM		active_fd_array
 type	POLLSET		LONG_LIVED	SYSTEM		pollset
diff --git a/erts/emulator/beam/erl_driver.h b/erts/emulator/beam/erl_driver.h
index 97a69140c3..5bea92e198 100644
--- a/erts/emulator/beam/erl_driver.h
+++ b/erts/emulator/beam/erl_driver.h
@@ -76,11 +76,10 @@ typedef struct {
 #  endif
 #endif
 
-/* Values for mode arg to driver_select() */
-#define ERL_DRV_READ  (1 << 0)
-#define ERL_DRV_WRITE (1 << 1)
-#define ERL_DRV_USE   (1 << 2)
-#define ERL_DRV_USE_NO_CALLBACK (ERL_DRV_USE | (1 << 3))
+#define ERL_DRV_READ  ((int)ERL_NIF_SELECT_READ)
+#define ERL_DRV_WRITE ((int)ERL_NIF_SELECT_WRITE)
+#define ERL_DRV_USE   ((int)ERL_NIF_SELECT_STOP)
+#define ERL_DRV_USE_NO_CALLBACK (ERL_DRV_USE | (ERL_DRV_USE  << 1))
 
 /* Old deprecated */
 #define DO_READ  ERL_DRV_READ
diff --git a/erts/emulator/beam/erl_drv_nif.h b/erts/emulator/beam/erl_drv_nif.h
index 2489099b5c..e4ebcdb1d4 100644
--- a/erts/emulator/beam/erl_drv_nif.h
+++ b/erts/emulator/beam/erl_drv_nif.h
@@ -49,6 +49,13 @@ typedef enum {
     ERL_DIRTY_JOB_IO_BOUND  = 2
 } ErlDirtyJobFlags;
 
+/* Values for enif_select AND mode arg for driver_select() */
+enum ErlNifSelectFlags {
+    ERL_NIF_SELECT_READ      = (1 << 0),
+    ERL_NIF_SELECT_WRITE     = (1 << 1),
+    ERL_NIF_SELECT_STOP      = (1 << 2)
+};
+
 #ifdef SIZEOF_CHAR
 #  define SIZEOF_CHAR_SAVED__ SIZEOF_CHAR
 #  undef SIZEOF_CHAR
diff --git a/erts/emulator/beam/erl_nif.c b/erts/emulator/beam/erl_nif.c
index 202f713f67..27abba7cfd 100644
--- a/erts/emulator/beam/erl_nif.c
+++ b/erts/emulator/beam/erl_nif.c
@@ -1904,37 +1904,10 @@ int enif_snprintf(char *buffer, size_t size, const char* format, ...)
  **       Memory managed (GC'ed) "resource" objects       **
  ***********************************************************/
 
-
-struct enif_resource_type_t
-{
-    struct enif_resource_type_t* next;   /* list of all resource types */
-    struct enif_resource_type_t* prev;    
-    struct erl_module_nif* owner;  /* that created this type and thus implements the destructor*/
-    ErlNifResourceDtor* dtor;      /* user destructor function */
-    erts_refc_t refc;  /* num of resources of this type (HOTSPOT warning)
-                          +1 for active erl_module_nif */
-    Eterm module;
-    Eterm name;
-};
-
 /* dummy node in circular list */
 struct enif_resource_type_t resource_type_list; 
 
-typedef struct enif_resource_t
-{
-    struct enif_resource_type_t* type;
-#ifdef DEBUG
-    erts_refc_t nif_refc;
-# ifdef ARCH_32
-    byte align__[4];
-# endif
-#endif
-
-    char data[1];
-}ErlNifResource;
-
 #define SIZEOF_ErlNifResource(SIZE) (offsetof(ErlNifResource,data) + (SIZE))
-#define DATA_TO_RESOURCE(PTR) ((ErlNifResource*)((char*)(PTR) - offsetof(ErlNifResource,data)))
 
 static ErlNifResourceType* find_resource_type(Eterm module, Eterm name)
 {
@@ -1997,24 +1970,23 @@ struct opened_resource_type
 
     ErlNifResourceFlags op;
     ErlNifResourceType* type;
-    ErlNifResourceDtor* new_dtor;
+    ErlNifResourceTypeInit new_callbacks;
 };
 static struct opened_resource_type* opened_rt_list = NULL;
 
-ErlNifResourceType*
-enif_open_resource_type(ErlNifEnv* env,
-			const char* module_str, 
-			const char* name_str, 
-			ErlNifResourceDtor* dtor,
-			ErlNifResourceFlags flags,
-			ErlNifResourceFlags* tried)
+static
+ErlNifResourceType* open_resource_type(ErlNifEnv* env,
+                                       const char* name_str,
+                                       const ErlNifResourceTypeInit* init,
+                                       ErlNifResourceFlags flags,
+                                       ErlNifResourceFlags* tried,
+                                       size_t sizeof_init)
 {
     ErlNifResourceType* type = NULL;
     ErlNifResourceFlags op = flags;
     Eterm module_am, name_am;
 
     ASSERT(erts_smp_thr_progress_is_blocking());
-    ASSERT(module_str == NULL); /* for now... */
     module_am = make_atom(env->mod_nif->mod->module);
     name_am = enif_make_atom(env, name_str);
 
@@ -2048,7 +2020,9 @@ enif_open_resource_type(ErlNifEnv* env,
 						sizeof(struct opened_resource_type));
 	ort->op = op;
 	ort->type = type;
-	ort->new_dtor = dtor;
+        sys_memzero(&ort->new_callbacks, sizeof(ErlNifResourceTypeInit));
+        ASSERT(sizeof_init > 0 && sizeof_init <= sizeof(ErlNifResourceTypeInit));
+        sys_memcpy(&ort->new_callbacks, init, sizeof_init);
 	ort->next = opened_rt_list;
 	opened_rt_list = ort;
     }
@@ -2058,6 +2032,31 @@ enif_open_resource_type(ErlNifEnv* env,
     return type;
 }
 
+ErlNifResourceType*
+enif_open_resource_type(ErlNifEnv* env,
+                        const char* module_str,
+                        const char* name_str,
+			ErlNifResourceDtor* dtor,
+			ErlNifResourceFlags flags,
+			ErlNifResourceFlags* tried)
+{
+    ErlNifResourceTypeInit init =  {dtor, NULL};
+    ASSERT(module_str == NULL); /* for now... */
+    return open_resource_type(env, name_str, &init, flags, tried,
+                              sizeof(init));
+}
+
+ErlNifResourceType*
+enif_open_resource_type_x(ErlNifEnv* env,
+                          const char* name_str,
+                          const ErlNifResourceTypeInit* init,
+                          ErlNifResourceFlags flags,
+                          ErlNifResourceFlags* tried)
+{
+    return open_resource_type(env, name_str, init, flags, tried,
+                              env->mod_nif->entry.sizeof_ErlNifResourceTypeInit);
+}
+
 static void commit_opened_resource_types(struct erl_module_nif* lib)
 {
     while (opened_rt_list) {
@@ -2076,7 +2075,8 @@ static void commit_opened_resource_types(struct erl_module_nif* lib)
 	}
 
 	type->owner = lib;
-	type->dtor = ort->new_dtor;
+	type->dtor = ort->new_callbacks.dtor;
+        type->stop = ort->new_callbacks.stop;
 
 	if (type->dtor != NULL) {
 	    erts_refc_inc(&lib->rt_dtor_cnt, 1);
@@ -2124,6 +2124,15 @@ static void nif_resource_dtor(Binary* bin)
     }
 }
 
+void erts_resource_stop(ErlNifResource* resource)
+{
+    struct enif_msg_environment_t msg_env;
+    ASSERT(resource->type->stop);
+    pre_nif_noproc(&msg_env, resource->type->owner, NULL);
+    resource->type->stop(&msg_env.env, resource->data);
+    post_nif_noproc(&msg_env);
+}
+
 void* enif_alloc_resource(ErlNifResourceType* type, size_t size)
 {
     Binary* bin = erts_create_magic_binary_x(SIZEOF_ErlNifResource(size),
@@ -3174,6 +3183,11 @@ static struct erl_module_nif* create_lib(const ErlNifEntry* src)
         dst->funcs = lib->_funcs_copy_;
         dst->options = 0;
     }
+    if (AT_LEAST_VERSION(src, 2, 12)) {
+        dst->sizeof_ErlNifResourceTypeInit = src->sizeof_ErlNifResourceTypeInit;
+    } else {
+        dst->sizeof_ErlNifResourceTypeInit = 0;
+    }
     return lib;
 };
 
diff --git a/erts/emulator/beam/erl_nif.h b/erts/emulator/beam/erl_nif.h
index 413b4f7343..ce8caaf729 100644
--- a/erts/emulator/beam/erl_nif.h
+++ b/erts/emulator/beam/erl_nif.h
@@ -52,7 +52,7 @@
 ** 2.11: 19.0 enif_snprintf 
 */
 #define ERL_NIF_MAJOR_VERSION 2
-#define ERL_NIF_MINOR_VERSION 11
+#define ERL_NIF_MINOR_VERSION 12
 
 /*
  * The emulator will refuse to load a nif-lib with a major version
@@ -122,6 +122,9 @@ typedef struct enif_entry_t
 
     /* Added in 2.7 */
     unsigned options;   /* Unused. Can be set to 0 or 1 (dirty sched config) */
+
+    /* Added in 2.12 */
+    size_t sizeof_ErlNifResourceTypeInit;
 }ErlNifEntry;
 
 
@@ -135,8 +138,20 @@ typedef struct
     void* ref_bin;
 }ErlNifBinary;
 
+typedef struct {
+    void (*dtor)(ErlNifEnv* env, void* obj);
+    void (*stop)(ErlNifEnv* env, void* obj); /* at ERL_NIF_SELECT_STOP event */
+} ErlNifResourceTypeInit;
+
 typedef struct enif_resource_type_t ErlNifResourceType;
 typedef void ErlNifResourceDtor(ErlNifEnv*, void*);
+typedef void ErlNifResourceStop(ErlNifEnv*, void*);
+typedef void ErlNifResourceExit(ErlNifEnv*, void*);
+
+//#ifndef ERL_SYS_DRV
+typedef int ErlNifEvent; /* An event to be selected on. */
+//#endif
+
 typedef enum
 {
     ERL_NIF_RT_CREATE = 1,
@@ -292,7 +307,8 @@ ERL_NIF_INIT_DECL(NAME)			\
 	FUNCS,				\
 	LOAD, RELOAD, UPGRADE, UNLOAD,	\
 	ERL_NIF_VM_VARIANT,		\
-	1		                \
+        1,                              \
+        sizeof(ErlNifResourceTypeInit)  \
     };                                  \
     ERL_NIF_INIT_BODY;                  \
     return &entry;			\
diff --git a/erts/emulator/beam/erl_nif_api_funcs.h b/erts/emulator/beam/erl_nif_api_funcs.h
index 9a8f216773..9163ce25eb 100644
--- a/erts/emulator/beam/erl_nif_api_funcs.h
+++ b/erts/emulator/beam/erl_nif_api_funcs.h
@@ -175,6 +175,8 @@ ERL_NIF_API_FUNC_DECL(size_t, enif_binary_to_term, (ErlNifEnv *env, const unsign
 ERL_NIF_API_FUNC_DECL(int, enif_port_command, (ErlNifEnv *env, const ErlNifPort* to_port, ErlNifEnv *msg_env, ERL_NIF_TERM msg));
 ERL_NIF_API_FUNC_DECL(int,enif_thread_type,(void));
 ERL_NIF_API_FUNC_DECL(int,enif_snprintf,(char * buffer, size_t size, const char *format, ...));
+ERL_NIF_API_FUNC_DECL(int,enif_select,(ErlNifEnv* env, ErlNifEvent e, enum ErlNifSelectFlags flags, void* obj, ERL_NIF_TERM ref));
+ERL_NIF_API_FUNC_DECL(ErlNifResourceType*,enif_open_resource_type_x,(ErlNifEnv*, const char* name_str, const ErlNifResourceTypeInit*, ErlNifResourceFlags flags, ErlNifResourceFlags* tried));
 
 /*
 ** ADD NEW ENTRIES HERE (before this comment) !!!
@@ -332,6 +334,8 @@ ERL_NIF_API_FUNC_DECL(int,enif_snprintf,(char * buffer, size_t size, const char
 #  define enif_port_command ERL_NIF_API_FUNC_MACRO(enif_port_command)
 #  define enif_thread_type ERL_NIF_API_FUNC_MACRO(enif_thread_type)
 #  define enif_snprintf ERL_NIF_API_FUNC_MACRO(enif_snprintf)
+#  define enif_select ERL_NIF_API_FUNC_MACRO(enif_select)
+#  define enif_open_resource_type_x ERL_NIF_API_FUNC_MACRO(enif_open_resource_type_x)
 
 /*
 ** ADD NEW ENTRIES HERE (before this comment)
diff --git a/erts/emulator/beam/global.h b/erts/emulator/beam/global.h
index 2b2f3c5cdc..5c5693a315 100644
--- a/erts/emulator/beam/global.h
+++ b/erts/emulator/beam/global.h
@@ -42,6 +42,7 @@
 #include "erl_utils.h"
 #include "erl_port.h"
 #include "erl_gc.h"
+#include "erl_nif.h"
 
 struct enif_func_t;
 
@@ -58,6 +59,33 @@ struct enif_environment_t /* ErlNifEnv */
     Process *tracee;
     int exiting; /* boolean (dirty nifs might return in exiting state) */
 };
+struct enif_resource_type_t
+{
+    struct enif_resource_type_t* next;   /* list of all resource types */
+    struct enif_resource_type_t* prev;
+    struct erl_module_nif* owner;  /* that created this type and thus implements the destructor*/
+    ErlNifResourceDtor* dtor;      /* user destructor function */
+    ErlNifResourceStop* stop;
+    erts_refc_t refc;  /* num of resources of this type (HOTSPOT warning)
+                          +1 for active erl_module_nif */
+    Eterm module;
+    Eterm name;
+};
+typedef struct enif_resource_t
+{
+    struct enif_resource_type_t* type;
+#ifdef DEBUG
+    erts_refc_t nif_refc;
+# ifdef ARCH_32
+    byte align__[4];
+# endif
+#endif
+
+    char data[1];
+}ErlNifResource;
+
+#define DATA_TO_RESOURCE(PTR) ((ErlNifResource*)((char*)(PTR) - offsetof(ErlNifResource,data)))
+
 extern void erts_pre_nif(struct enif_environment_t*, Process*,
 			 struct erl_module_nif*, Process* tracee);
 extern void erts_post_nif(struct enif_environment_t* env);
@@ -67,6 +95,7 @@ extern void erts_pre_dirty_nif(ErtsSchedulerData *,
 			       struct erl_module_nif*);
 extern void erts_post_dirty_nif(struct enif_environment_t* env);
 #endif
+extern void erts_resource_stop(ErlNifResource* resource);
 extern Eterm erts_nif_taints(Process* p);
 extern void erts_print_nif_taints(fmtfn_t to, void* to_arg);
 void erts_unload_nif(struct erl_module_nif* nif);
diff --git a/erts/emulator/sys/common/erl_check_io.c b/erts/emulator/sys/common/erl_check_io.c
index 2c138e1746..6f61fc8a28 100644
--- a/erts/emulator/sys/common/erl_check_io.c
+++ b/erts/emulator/sys/common/erl_check_io.c
@@ -53,6 +53,8 @@ typedef char EventStateType;
 #define ERTS_EV_TYPE_DRV_SEL  ((EventStateType) 1) /* driver_select */
 #define ERTS_EV_TYPE_DRV_EV   ((EventStateType) 2) /* driver_event */
 #define ERTS_EV_TYPE_STOP_USE ((EventStateType) 3) /* pending stop_select */
+#define ERTS_EV_TYPE_NIF      ((EventStateType) 4) /* enif_select */
+#define ERTS_EV_TYPE_STOP_NIF ((EventStateType) 5) /* pending nif stop */
 
 typedef char EventStateFlags;
 #define ERTS_EV_FLAG_USED         ((EventStateFlags) 1)   /* ERL_DRV_USE has been turned on */
@@ -122,7 +124,11 @@ typedef struct {
 #if ERTS_CIO_HAVE_DRV_EVENT
 	ErtsDrvEventDataState *event;     /* ERTS_EV_TYPE_DRV_EV */
 #endif
-	erts_driver_t* drv_ptr;           /* ERTS_EV_TYPE_STOP_USE */
+        ErtsNifSelectDataState *nif;      /* ERTS_EV_TYPE_NIF */
+        union {
+            erts_driver_t*  drv_ptr;    /* ERTS_EV_TYPE_STOP_USE */
+            ErlNifResource* resource;   /* ERTS_EV_TYPE_STOP_NIF */
+        }stop;
     } driver;
     ErtsPollEvents events;
     unsigned short remove_cnt; /* number of removed_fd's referring to this fd */
@@ -212,11 +218,18 @@ static ERTS_INLINE void hash_erase_drv_ev_state(ErtsDrvEventState *state)
 
 static void stale_drv_select(Eterm id, ErtsDrvEventState *state, int mode);
 static void drv_select_steal(ErlDrvPort ix, ErtsDrvEventState *state,
-			 int mode, int on);
+                             int mode, int on);
+static void nif_select_steal(ErtsDrvEventState *state, int mode,
+                             ErlNifResource* resource, Eterm ref);
+
 static void print_drv_select_op(erts_dsprintf_buf_t *dsbufp,
                                 ErlDrvPort ix, ErtsSysFdType fd, int mode, int on);
+static void print_nif_select_op(erts_dsprintf_buf_t*, ErtsSysFdType,
+                                int mode, ErlNifResource*, Eterm ref);
+
 #ifdef ERTS_SYS_CONTINOUS_FD_NUMBERS
-static void select_large_fd_error(ErlDrvPort, ErtsSysFdType, int, int);
+static void drv_select_large_fd_error(ErlDrvPort, ErtsSysFdType, int, int);
+static void nif_select_large_fd_error(ErtsSysFdType, int, ErlNifResource*,Eterm ref);
 #endif
 #if ERTS_CIO_HAVE_DRV_EVENT
 static void drv_event_steal(ErlDrvPort ix, ErtsDrvEventState *state,
@@ -227,8 +240,12 @@ static void print_drv_event_op(erts_dsprintf_buf_t *dsbufp,
 static void event_large_fd_error(ErlDrvPort, ErtsSysFdType, ErlDrvEventData);
 #endif
 #endif
-static void steal_pending_stop_use(erts_dsprintf_buf_t*, ErlDrvPort,
-                                   ErtsDrvEventState*, int mode, int on);
+static void
+steal_pending_stop_use(erts_dsprintf_buf_t*, ErlDrvPort, ErtsDrvEventState*,
+                       int mode, int on);
+static void
+steal_pending_stop_nif(erts_dsprintf_buf_t *dsbufp, ErlNifResource*,
+                       ErtsDrvEventState *state, int mode, int on);
 
 #ifdef ERTS_SMP
 ERTS_SCHED_PREF_QUICK_ALLOC_IMPL(removed_fd, struct removed_fd, 64, ERTS_ALC_T_FD_LIST)
@@ -263,6 +280,18 @@ alloc_drv_select_data(void)
     return dsp;
 }
 
+static ERTS_INLINE ErtsNifSelectDataState *
+alloc_nif_select_data(void)
+{
+    ErtsNifSelectDataState *dsp = erts_alloc(ERTS_ALC_T_NIF_SEL_D_STATE,
+					     sizeof(ErtsNifSelectDataState));
+    dsp->in.pid = NIL;
+    dsp->out.pid = NIL;
+    dsp->in.ddeselect_cnt = 0;
+    dsp->out.ddeselect_cnt = 0;
+    return dsp;
+}
+
 static ERTS_INLINE void
 free_drv_select_data(ErtsDrvSelectDataState *dsp)
 {
@@ -271,6 +300,12 @@ free_drv_select_data(ErtsDrvSelectDataState *dsp)
     erts_free(ERTS_ALC_T_DRV_SEL_D_STATE, dsp);   
 }
 
+static ERTS_INLINE void
+free_nif_select_data(ErtsNifSelectDataState *dsp)
+{
+    erts_free(ERTS_ALC_T_NIF_SEL_D_STATE, dsp);
+}
+
 #if ERTS_CIO_HAVE_DRV_EVENT
 
 static ERTS_INLINE ErtsDrvEventDataState *
@@ -352,6 +387,7 @@ forget_removed(struct pollset_info* psi)
     erts_smp_spin_unlock(&psi->removed_list_lock);
 
     while (fdlp) {
+        ErlNifResource* resource = NULL;
 	erts_driver_t* drv_ptr = NULL;
 	erts_smp_mtx_t* mtx;
 	ErtsSysFdType fd;
@@ -372,15 +408,25 @@ forget_removed(struct pollset_info* psi)
 	ASSERT(state->remove_cnt > 0);
 	if (--state->remove_cnt == 0) {
 	    switch (state->type) {
+	    case ERTS_EV_TYPE_STOP_NIF:
+		/* Now we can call stop */
+		resource = state->driver.stop.resource;
+                state->driver.stop.resource = NULL;
+                ASSERT(resource);
+		state->type = ERTS_EV_TYPE_NONE;
+		state->flags &= ~ERTS_EV_FLAG_USED;
+                goto case_ERTS_EV_TYPE_NONE;
+
 	    case ERTS_EV_TYPE_STOP_USE:
 		/* Now we can call stop_select */
-		drv_ptr = state->driver.drv_ptr;
+		drv_ptr = state->driver.stop.drv_ptr;
 		ASSERT(drv_ptr);
 		state->type = ERTS_EV_TYPE_NONE;
 		state->flags &= ~ERTS_EV_FLAG_USED;
-		state->driver.drv_ptr = NULL;  
+		state->driver.stop.drv_ptr = NULL;
 		/* Fall through */
-	    case ERTS_EV_TYPE_NONE:
+            case ERTS_EV_TYPE_NONE:
+            case_ERTS_EV_TYPE_NONE:
 #ifndef ERTS_SYS_CONTINOUS_FD_NUMBERS
 		hash_erase_drv_ev_state(state);
 #endif
@@ -403,6 +449,11 @@ forget_removed(struct pollset_info* psi)
 		erts_ddll_dereference_driver(drv_ptr->handle);
 	    }
 	}
+        if (resource) {
+            erts_resource_stop(resource);
+            enif_release_resource(resource->data);
+        }
+
 	tofree = fdlp;
 	fdlp = fdlp->next;
 	removed_fd_free(tofree);
@@ -440,7 +491,8 @@ grow_drv_ev_state(int min_ix)
 #if ERTS_CIO_HAVE_DRV_EVENT
 	    drv_ev_state[i].driver.event = NULL;
 #endif
-	    drv_ev_state[i].driver.drv_ptr = NULL;
+	    drv_ev_state[i].driver.stop.drv_ptr = NULL;
+            drv_ev_state[i].driver.nif = NULL;
 	    drv_ev_state[i].events = 0;
 	    drv_ev_state[i].remove_cnt = 0;
 	    drv_ev_state[i].type = ERTS_EV_TYPE_NONE;
@@ -480,6 +532,7 @@ abort_tasks(ErtsDrvEventState *state, int mode)
 		       ERTS_EV_TYPE_DRV_EV);
 	    return;
 #endif
+        case ERTS_EV_TYPE_NIF:
 	case ERTS_EV_TYPE_NONE:
 	    return;
 	default:
@@ -534,6 +587,14 @@ deselect(ErtsDrvEventState *state, int mode)
 
     if (!(state->events)) {
 	switch (state->type) {
+        case ERTS_EV_TYPE_NIF:
+            state->driver.nif->in.pid = NIL;
+            state->driver.nif->out.pid = NIL;
+            state->driver.nif->in.ddeselect_cnt = 0;
+            state->driver.nif->out.ddeselect_cnt = 0;
+            enif_release_resource(state->driver.stop.resource);
+            state->driver.stop.resource = NULL;
+            break;
 	case ERTS_EV_TYPE_DRV_SEL:
 	    state->driver.select->inport = NIL;
 	    state->driver.select->outport = NIL;
@@ -569,7 +630,8 @@ check_fd_cleanup(ErtsDrvEventState *state,
 #if ERTS_CIO_HAVE_DRV_EVENT
 		 ErtsDrvEventDataState **free_event,
 #endif
-		 ErtsDrvSelectDataState **free_select)
+		 ErtsDrvSelectDataState **free_select,
+                 ErtsNifSelectDataState **free_nif)
 {
     erts_aint_t current_cio_time;
 
@@ -586,6 +648,12 @@ check_fd_cleanup(ErtsDrvEventState *state,
 	state->driver.select = NULL;
     }
 
+    *free_nif = NULL;
+    if (state->driver.nif && (state->type != ERTS_EV_TYPE_NIF)) {
+        *free_nif = state->driver.nif;
+        state->driver.nif = NULL;
+    }
+
 #if ERTS_CIO_HAVE_DRV_EVENT
     *free_event = NULL;
     if (state->driver.event
@@ -617,12 +685,14 @@ check_cleanup_active_fd(ErtsSysFdType fd,
 			ErtsPollControlEntry *pce,
 			int *pce_ix,
 #endif
-			erts_aint_t current_cio_time)
+			erts_aint_t current_cio_time,
+                        int may_sleep)
 {
     ErtsDrvEventState *state;
     int active = 0;
     erts_smp_mtx_t *mtx = fd_mtx(fd);
     void *free_select = NULL;
+    void *free_nif = NULL;
 #if ERTS_CIO_HAVE_DRV_EVENT
     void *free_event = NULL;
 #endif
@@ -682,6 +752,41 @@ check_cleanup_active_fd(ErtsSysFdType fd,
 	    }
 	}
 
+        if (state->driver.nif) {
+#if ERTS_CIO_DEFER_ACTIVE_EVENTS
+#  error Windows
+#endif
+            int do_wake = 0;
+            ErtsPollEvents rm_events = 0;
+            if (state->driver.nif->in.ddeselect_cnt) {
+                ASSERT(state->type == ERTS_EV_TYPE_NIF);
+                ASSERT(state->events & ERTS_POLL_EV_IN);
+                ASSERT(is_nil(state->driver.nif->in.pid));
+                if (may_sleep || state->driver.nif->in.ddeselect_cnt == 1) {
+                    rm_events = ERTS_POLL_EV_IN;
+                    state->driver.nif->in.ddeselect_cnt = 0;
+                }
+            }
+            if (state->driver.nif->out.ddeselect_cnt) {
+                ASSERT(state->type == ERTS_EV_TYPE_NIF);
+                ASSERT(state->events & ERTS_POLL_EV_OUT);
+                ASSERT(is_nil(state->driver.nif->out.pid));
+                if (may_sleep || state->driver.nif->out.ddeselect_cnt == 1) {
+                    rm_events |= ERTS_POLL_EV_OUT;
+                    state->driver.nif->out.ddeselect_cnt = 0;
+                }
+            }
+            if (rm_events) {
+                state->events = ERTS_CIO_POLL_CTL(pollset.ps, state->fd, rm_events, 0, &do_wake);
+            }
+            if (state->events)
+                active = 1;
+            else if (state->type != ERTS_EV_TYPE_NIF) {
+                free_nif = state->driver.nif;
+                state->driver.nif = NULL;
+            }
+        }
+
 #if ERTS_CIO_HAVE_DRV_EVENT
 	if (state->driver.event) {
 	    if (is_iotask_active(&state->driver.event->iotask, current_cio_time)) {
@@ -722,6 +827,8 @@ check_cleanup_active_fd(ErtsSysFdType fd,
 
     if (free_select)
 	free_drv_select_data(free_select);
+    if (free_nif)
+        free_nif_select_data(free_nif);
 #if ERTS_CIO_HAVE_DRV_EVENT
     if (free_event)
 	free_drv_event_data(free_event);
@@ -746,7 +853,7 @@ check_cleanup_active_fd(ErtsSysFdType fd,
 }
 
 static void
-check_cleanup_active_fds(erts_aint_t current_cio_time)
+check_cleanup_active_fds(erts_aint_t current_cio_time, int may_sleep)
 {
     int six = pollset.active_fd.six;
     int eix = pollset.active_fd.eix;
@@ -773,7 +880,8 @@ check_cleanup_active_fds(erts_aint_t current_cio_time)
 				     pctrl_entries,
 				     &pctrl_ix,
 #endif
-				     current_cio_time)) {
+				     current_cio_time,
+                                     may_sleep)) {
 	    no--;
 	    if (ix == six) {
 #ifdef DEBUG
@@ -831,7 +939,6 @@ add_active_fd(ErtsSysFdType fd)
     int eix = pollset.active_fd.eix;
     int size = pollset.active_fd.size;
     
-
     pollset.active_fd.array[eix] = fd;
 
     erts_smp_atomic32_set_relb(&pollset.active_fd.no,
@@ -867,6 +974,7 @@ ERTS_CIO_EXPORT(driver_select)(ErlDrvPort ix,
     ErtsDrvEventDataState *free_event = NULL;
 #endif
     ErtsDrvSelectDataState *free_select = NULL;
+    ErtsNifSelectDataState *free_nif = NULL;
 #ifdef USE_VM_PROBES
     DTRACE_CHARBUF(name, 64);
 #endif
@@ -882,7 +990,7 @@ ERTS_CIO_EXPORT(driver_select)(ErlDrvPort ix,
 	    return -1;    
 	}
 	if (fd >= max_fds) {
-	    select_large_fd_error(ix, fd, mode, on);
+	    drv_select_large_fd_error(ix, fd, mode, on);
 	    return -1;
 	}
 	grow_drv_ev_state(fd);
@@ -920,20 +1028,32 @@ ERTS_CIO_EXPORT(driver_select)(ErlDrvPort ix,
     }
 #endif
 
+    switch (state->type) {
 #if ERTS_CIO_HAVE_DRV_EVENT
-    if (state->type == ERTS_EV_TYPE_DRV_EV)
-	drv_select_steal(ix, state, mode, on);
+    case ERTS_EV_TYPE_DRV_EV:
 #endif
-    if (state->type == ERTS_EV_TYPE_STOP_USE) {
-	erts_dsprintf_buf_t *dsbufp = erts_create_logger_dsbuf();
-	print_drv_select_op(dsbufp, ix, state->fd, mode, on);
-	steal_pending_stop_use(dsbufp, ix, state, mode, on);
-	if (state->type == ERTS_EV_TYPE_STOP_USE) {
-	    ret = 0;
-	    goto done; /* stop_select still pending */
-	}
-	ASSERT(state->type == ERTS_EV_TYPE_NONE);
-    }
+    case ERTS_EV_TYPE_NIF:
+        drv_select_steal(ix, state, mode, on);
+        break;
+    case ERTS_EV_TYPE_STOP_USE: {
+        erts_dsprintf_buf_t *dsbufp = erts_create_logger_dsbuf();
+        print_drv_select_op(dsbufp, ix, state->fd, mode, on);
+        steal_pending_stop_use(dsbufp, ix, state, mode, on);
+        if (state->type == ERTS_EV_TYPE_STOP_USE) {
+            ret = 0;
+            goto done; /* stop_select still pending */
+        }
+        ASSERT(state->type == ERTS_EV_TYPE_NONE);
+        break;
+    }
+    case ERTS_EV_TYPE_STOP_NIF: {
+        erts_dsprintf_buf_t *dsbufp = erts_create_logger_dsbuf();
+        print_drv_select_op(dsbufp, ix, state->fd, mode, on);
+        steal_pending_stop_nif(dsbufp, NULL, state, mode, on);
+        ASSERT(state->type == ERTS_EV_TYPE_NONE);
+        break;
+
+    }}
 
     if (mode & ERL_DRV_READ) {
 	if (state->type == ERTS_EV_TYPE_DRV_SEL) {
@@ -1037,7 +1157,7 @@ ERTS_CIO_EXPORT(driver_select)(ErlDrvPort ix,
 		else {
 		    /* Not safe to close fd, postpone stop_select callback. */
 		    state->type = ERTS_EV_TYPE_STOP_USE;
-		    state->driver.drv_ptr = drv_ptr;
+		    state->driver.stop.drv_ptr = drv_ptr;
 		    if (drv_ptr->handle) {
 			erts_ddll_reference_referenced_driver(drv_ptr->handle);
 		    }
@@ -1054,7 +1174,8 @@ done:
 #if ERTS_CIO_HAVE_DRV_EVENT
 		     &free_event,
 #endif
-		     &free_select);
+		     &free_select,
+                     &free_nif);
 
 done_unknown:
     erts_smp_mtx_unlock(fd_mtx(fd));
@@ -1067,6 +1188,9 @@ done_unknown:
     }
     if (free_select)
 	free_drv_select_data(free_select);
+    if (free_nif)
+        free_nif_select_data(free_nif);
+
 #if ERTS_CIO_HAVE_DRV_EVENT
     if (free_event)
 	free_drv_event_data(free_event);
@@ -1075,6 +1199,269 @@ done_unknown:
 }
 
 int
+ERTS_CIO_EXPORT(enif_select)(ErlNifEnv* env,
+                             ErlNifEvent e,
+                             enum ErlNifSelectFlags mode,
+                             void* obj,
+                             Eterm ref)
+{
+    int on;
+    const Eterm id = env->proc->common.id;
+    ErlNifResource* resource = DATA_TO_RESOURCE(obj);
+    ErtsSysFdType fd = (ErtsSysFdType) e;
+    ErtsPollEvents ctl_events = (ErtsPollEvents) 0;
+    ErtsPollEvents new_events, old_events;
+    ErtsDrvEventState *state;
+    int wake_poller;
+    int ret;
+    enum { NO_STOP=0, CALL_STOP, CALL_STOP_AND_RELEASE } call_stop = NO_STOP;
+#if ERTS_CIO_HAVE_DRV_EVENT
+    ErtsDrvEventDataState *free_event = NULL;
+#endif
+    ErtsDrvSelectDataState *free_select = NULL;
+    ErtsNifSelectDataState *free_nif = NULL;
+#ifdef USE_VM_PROBES
+    DTRACE_CHARBUF(name, 64);
+#endif
+
+#ifdef ERTS_SYS_CONTINOUS_FD_NUMBERS
+    if ((unsigned)fd >= (unsigned)erts_smp_atomic_read_nob(&drv_ev_state_len)) {
+	if (fd < 0) {
+	    return -1;
+	}
+	if (fd >= max_fds) {
+	    nif_select_large_fd_error(fd, mode, resource, ref);
+            return -1;
+	}
+	grow_drv_ev_state(fd);
+    }
+#endif
+
+    erts_smp_mtx_lock(fd_mtx(fd));
+
+#ifdef ERTS_SYS_CONTINOUS_FD_NUMBERS
+    state = &drv_ev_state[(int) fd];
+#else
+    state = hash_get_drv_ev_state(fd); /* may be NULL! */
+#endif
+
+    if (mode & ERL_NIF_SELECT_STOP) {
+        ASSERT(resource->type->stop);
+        if (IS_FD_UNKNOWN(state)) {
+            /* fast track to stop callback */
+            call_stop = CALL_STOP;
+            ret = 0;
+            goto done_unknown;
+        }
+        on = 0;
+        mode = ERL_DRV_READ | ERL_DRV_WRITE | ERL_DRV_USE;
+        wake_poller = 1; /* to eject fd from pollset (if needed) */
+    }
+    else {
+        on = 1;
+        ASSERT(mode);
+        wake_poller = 0;
+    }
+
+#ifndef ERTS_SYS_CONTINOUS_FD_NUMBERS
+    if (state == NULL) {
+	state = hash_new_drv_ev_state(fd);
+    }
+#endif
+
+    switch (state->type) {
+    case ERTS_EV_TYPE_NIF:
+        /*
+         * Changing resource is considered stealing.
+         * Changing process and/or ref is ok (I think?).
+         */
+        if (state->driver.stop.resource != resource)
+            nif_select_steal(state, ERL_DRV_READ | ERL_DRV_WRITE, resource, ref);
+        break;
+#if ERTS_CIO_HAVE_DRV_EVENT
+    case ERTS_EV_TYPE_DRV_EV:
+#endif
+    case ERTS_EV_TYPE_DRV_SEL:
+        nif_select_steal(state, mode, resource, ref);
+        break;
+    case ERTS_EV_TYPE_STOP_USE: {
+        erts_dsprintf_buf_t *dsbufp = erts_create_logger_dsbuf();
+        print_nif_select_op(dsbufp, fd, mode, resource, ref);
+        steal_pending_stop_use(dsbufp, ERTS_INVALID_ERL_DRV_PORT, state, mode, on);
+        ASSERT(state->type == ERTS_EV_TYPE_NONE);
+        break;
+    }
+    case ERTS_EV_TYPE_STOP_NIF: {
+        erts_dsprintf_buf_t *dsbufp = erts_create_logger_dsbuf();
+        print_nif_select_op(dsbufp, fd, mode, resource, ref);
+        steal_pending_stop_nif(dsbufp, resource, state, mode, on);
+        if (state->type == ERTS_EV_TYPE_STOP_NIF) {
+            ret = 0;
+            goto done;
+        }
+        ASSERT(state->type == ERTS_EV_TYPE_NONE);
+        break;
+    }}
+
+    ASSERT(state->type == ERTS_EV_TYPE_NONE ||
+           state->type == ERTS_EV_TYPE_NIF);
+
+    if (mode & ERL_DRV_READ) {
+	ctl_events |= ERTS_POLL_EV_IN;
+    }
+    if (mode & ERL_DRV_WRITE) {
+	ctl_events |= ERTS_POLL_EV_OUT;
+    }
+
+    ASSERT((state->type == ERTS_EV_TYPE_NIF) ||
+	   (state->type == ERTS_EV_TYPE_NONE && !state->events));
+
+    new_events = ERTS_CIO_POLL_CTL(pollset.ps, state->fd, ctl_events, on, &wake_poller);
+
+    if (new_events & (ERTS_POLL_EV_ERR|ERTS_POLL_EV_NVAL)) {
+	if (state->type == ERTS_EV_TYPE_NIF && !state->events) {
+	    state->type = ERTS_EV_TYPE_NONE;
+	    state->flags &= ~ERTS_EV_FLAG_USED;
+	    state->driver.nif->in.pid = NIL;
+	    state->driver.nif->out.pid = NIL;
+            state->driver.nif->in.ddeselect_cnt = 0;
+            state->driver.nif->out.ddeselect_cnt = 0;
+            state->driver.stop.resource = NULL;
+	}
+	ret = -1;
+	goto done;
+    }
+
+    old_events = state->events;
+
+    ASSERT(on
+	   ? (new_events == (state->events | ctl_events))
+	   : (new_events == (state->events & ~ctl_events)));
+
+    ASSERT(state->type == ERTS_EV_TYPE_NIF
+	   || state->type == ERTS_EV_TYPE_NONE);
+
+    state->events = new_events;
+    if (ctl_events) {
+	if (on) {
+            Uint32* refn;
+	    if (!state->driver.nif)
+		state->driver.nif = alloc_nif_select_data();
+	    if (state->type == ERTS_EV_TYPE_NONE) {
+		state->type = ERTS_EV_TYPE_NIF;
+                state->driver.stop.resource = resource;
+                enif_keep_resource(resource->data);
+            }
+            ASSERT(state->type == ERTS_EV_TYPE_NIF);
+            ASSERT(state->driver.stop.resource == resource);
+	    if (ctl_events & ERTS_POLL_EV_IN) {
+                ASSERT(is_nil(state->driver.nif->in.pid));
+		state->driver.nif->in.pid = id;
+                if (is_immed(ref)) {
+                    state->driver.nif->in.immed = ref;
+                } else {
+                    ASSERT(is_internal_ref(ref));
+                    refn = internal_ref_numbers(ref);
+                    state->driver.nif->in.immed = THE_NON_VALUE;
+                    state->driver.nif->in.refn[0] = refn[0];
+                    state->driver.nif->in.refn[1] = refn[1];
+                    state->driver.nif->in.refn[2] = refn[2];
+                }
+                state->driver.nif->in.ddeselect_cnt = 0;
+            }
+	    if (ctl_events & ERTS_POLL_EV_OUT) {
+                ASSERT(is_nil(state->driver.nif->out.pid));
+		state->driver.nif->out.pid = id;
+                if (is_immed(ref)) {
+                    state->driver.nif->out.immed = ref;
+                } else {
+                    ASSERT(is_internal_ref(ref));
+                    refn = internal_ref_numbers(ref);
+                    state->driver.nif->out.immed = THE_NON_VALUE;
+                    state->driver.nif->out.refn[0] = refn[0];
+                    state->driver.nif->out.refn[1] = refn[1];
+                    state->driver.nif->out.refn[2] = refn[2];
+                }
+                state->driver.nif->out.ddeselect_cnt = 0;
+            }
+            state->flags |= ERTS_EV_FLAG_USED;
+	}
+	else { /* off */
+	    if (state->type == ERTS_EV_TYPE_NIF) {
+                //erts_fprintf(stderr, "SVERK: enif select clear fd=%d inpid=%T inrsrc=%p\n",
+                //             state->fd, state->driver.nif->inpid,
+                //             state->driver.nif->in.resource);
+                state->driver.nif->in.pid = NIL;
+                state->driver.nif->out.pid = NIL;
+                state->driver.nif->in.ddeselect_cnt = 0;
+                state->driver.nif->out.ddeselect_cnt = 0;
+                state->flags &= ~ERTS_EV_FLAG_USED;
+                if (old_events != 0) {
+                    remember_removed(state, &pollset);
+                }
+	    }
+            ASSERT(new_events==0);
+            if (state->remove_cnt == 0 || !wake_poller) {
+                /* Safe to close fd now as it is not in pollset
+		   or there was no need to eject fd (kernel poll) */
+                //erts_fprintf(stderr, "SVERK : enif_select calling stop before return\n");
+                if (state->type == ERTS_EV_TYPE_NIF) {
+                    ASSERT(state->driver.stop.resource == resource);
+                    call_stop = CALL_STOP_AND_RELEASE;
+                    state->driver.stop.resource = NULL;
+                }
+                else {
+                    ASSERT(!state->driver.stop.resource);
+                    call_stop = CALL_STOP;
+                }
+                state->type = ERTS_EV_TYPE_NONE;
+            }
+            else {
+                /* Not safe to close fd, postpone stop_select callback. */
+                //erts_fprintf(stderr, "SVERK: enif_select schedule stop\n");
+                if (state->type == ERTS_EV_TYPE_NONE) {
+                    ASSERT(!state->driver.stop.resource);
+                    state->driver.stop.resource = resource;
+                    enif_keep_resource(resource);
+                }
+                state->type = ERTS_EV_TYPE_STOP_NIF;
+	    }
+	}
+    }
+
+    ret = 0;
+
+done:
+
+    check_fd_cleanup(state,
+#if ERTS_CIO_HAVE_DRV_EVENT
+		     &free_event,
+#endif
+		     &free_select,
+                     &free_nif);
+
+done_unknown:
+    erts_smp_mtx_unlock(fd_mtx(fd));
+    if (call_stop) {
+        erts_resource_stop(resource);
+        if (call_stop == CALL_STOP_AND_RELEASE) {
+            enif_release_resource(resource->data);
+        }
+    }
+    if (free_select)
+	free_drv_select_data(free_select);
+    if (free_nif)
+        free_nif_select_data(free_nif);
+
+#if ERTS_CIO_HAVE_DRV_EVENT
+    if (free_event)
+	free_drv_event_data(free_event);
+#endif
+    return ret;
+}
+
+
+int
 ERTS_CIO_EXPORT(driver_event)(ErlDrvPort ix,
 			      ErlDrvEvent e,
 			      ErlDrvEventData event_data)
@@ -1094,6 +1481,7 @@ ERTS_CIO_EXPORT(driver_event)(ErlDrvPort ix,
     ErtsDrvEventDataState *free_event;
 #endif
     ErtsDrvSelectDataState *free_select;
+    ErtsNifSelectDataState *free_nif;
     Port *prt = erts_drvport2port(ix);
 
     if (prt == ERTS_INVALID_ERL_DRV_PORT)
@@ -1203,12 +1591,15 @@ done:
 #if ERTS_CIO_HAVE_DRV_EVENT
 		     &free_event,
 #endif
-		     &free_select);
+		     &free_select,
+                     &free_nif);
 
     erts_smp_mtx_unlock(fd_mtx(fd));
 
     if (free_select)
 	free_drv_select_data(free_select);
+    if (free_nif)
+        free_nif_select_data(free_nif);
 #if ERTS_CIO_HAVE_DRV_EVENT
     if (free_event)
 	free_drv_event_data(free_event);
@@ -1244,13 +1635,19 @@ need2steal(ErtsDrvEventState *state, int mode)
 				  state,
 				  ERL_DRV_WRITE);
 	break;
+    case ERTS_EV_TYPE_NIF:
+        ASSERT(state->driver.stop.resource);
+        do_steal = 1;
+        break;
+
 #if ERTS_CIO_HAVE_DRV_EVENT
     case ERTS_EV_TYPE_DRV_EV:
 	do_steal |= chk_stale(state->driver.event->port, state, 0);
 	break;
 #endif
     case ERTS_EV_TYPE_STOP_USE:
-	ASSERT(0);
+    case ERTS_EV_TYPE_STOP_NIF:
+        ASSERT(0);
 	break;
     default:
 	break;
@@ -1311,6 +1708,25 @@ steal(erts_dsprintf_buf_t *dsbufp, ErtsDrvEventState *state, int mode)
 	erts_dsprintf(dsbufp, "\n");
 	break;
     }
+    case ERTS_EV_TYPE_NIF: {
+        Eterm iid = state->driver.nif->in.pid;
+        Eterm oid = state->driver.nif->out.pid;
+        const char* with = "with";
+        ErlNifResourceType* rt = state->driver.stop.resource->type;
+
+        erts_dsprintf(dsbufp, "resource %T:%T", rt->module, rt->name);
+
+        if (is_not_nil(iid)) {
+            erts_dsprintf(dsbufp, " %s in-pid %T", with, iid);
+            with = "and";
+        }
+        if (is_not_nil(oid)) {
+            erts_dsprintf(dsbufp, " %s out-pid %T", with, oid);
+        }
+        deselect(state, 0);
+        erts_dsprintf(dsbufp, "\n");
+        break;
+    }
 #if ERTS_CIO_HAVE_DRV_EVENT
     case ERTS_EV_TYPE_DRV_EV: {
 	Eterm eid = state->driver.event->port;
@@ -1328,7 +1744,8 @@ steal(erts_dsprintf_buf_t *dsbufp, ErtsDrvEventState *state, int mode)
 	break;
     }
 #endif
-    case ERTS_EV_TYPE_STOP_USE: {
+    case ERTS_EV_TYPE_STOP_USE:
+    case ERTS_EV_TYPE_STOP_NIF: {
 	ASSERT(0);
 	break;
     }
@@ -1358,6 +1775,23 @@ print_drv_select_op(erts_dsprintf_buf_t *dsbufp,
 }
 
 static void
+print_nif_select_op(erts_dsprintf_buf_t *dsbufp,
+                    ErtsSysFdType fd, int mode,
+                    ErlNifResource* resource, Eterm ref)
+{
+    erts_dsprintf(dsbufp,
+		  "enif_select(_, %d,%s%s%s, %T:%T, %T) ",
+		  (int) GET_FD(fd),
+		  mode & ERL_NIF_SELECT_READ ? " READ" : "",
+		  mode & ERL_NIF_SELECT_WRITE ? " WRITE" : "",
+		  mode & ERL_NIF_SELECT_STOP ? " STOP" : "",
+		  resource->type->module,
+                  resource->type->name,
+                  ref);
+}
+
+
+static void
 drv_select_steal(ErlDrvPort ix, ErtsDrvEventState *state, int mode, int on)
 {
     if (need2steal(state, mode)) {
@@ -1368,6 +1802,18 @@ drv_select_steal(ErlDrvPort ix, ErtsDrvEventState *state, int mode, int on)
     }
 }
 
+static void
+nif_select_steal(ErtsDrvEventState *state, int mode,
+                 ErlNifResource* resource, Eterm ref)
+{
+    if (need2steal(state, mode)) {
+	erts_dsprintf_buf_t *dsbufp = erts_create_logger_dsbuf();
+	print_nif_select_op(dsbufp, state->fd, mode, resource, ref);
+	steal(dsbufp, state, mode);
+	erts_send_error_to_logger_nogl(dsbufp);
+    }
+}
+
 #ifdef ERTS_SYS_CONTINOUS_FD_NUMBERS
 static void
 large_fd_error_common(erts_dsprintf_buf_t *dsbufp, ErtsSysFdType fd)
@@ -1378,7 +1824,7 @@ large_fd_error_common(erts_dsprintf_buf_t *dsbufp, ErtsSysFdType fd)
 }
 
 static void
-select_large_fd_error(ErlDrvPort ix, ErtsSysFdType fd, int mode, int on)
+drv_select_large_fd_error(ErlDrvPort ix, ErtsSysFdType fd, int mode, int on)
 {
     erts_dsprintf_buf_t *dsbufp = erts_create_logger_dsbuf();
     print_drv_select_op(dsbufp, ix, fd, mode, on);
@@ -1386,6 +1832,16 @@ select_large_fd_error(ErlDrvPort ix, ErtsSysFdType fd, int mode, int on)
     large_fd_error_common(dsbufp, fd);
     erts_send_error_to_logger_nogl(dsbufp);
 }
+static void
+nif_select_large_fd_error(ErtsSysFdType fd, int mode,
+                          ErlNifResource* resource, Eterm ref)
+{
+    erts_dsprintf_buf_t *dsbufp = erts_create_logger_dsbuf();
+    print_nif_select_op(dsbufp, fd, mode, resource, ref);
+    erts_dsprintf(dsbufp, "failed: ");
+    large_fd_error_common(dsbufp, fd);
+    erts_send_error_to_logger_nogl(dsbufp);
+}
 #endif /* ERTS_SYS_CONTINOUS_FD_NUMBERS */
 
 
@@ -1394,38 +1850,78 @@ static void
 steal_pending_stop_use(erts_dsprintf_buf_t *dsbufp, ErlDrvPort ix,
                        ErtsDrvEventState *state, int mode, int on)
 {
+    int cancel = 0;
     ASSERT(state->type == ERTS_EV_TYPE_STOP_USE);
-    erts_dsprintf(dsbufp, "failed: fd=%d (re)selected before stop_select "
-		          "was called for driver %s\n",
-		  (int) GET_FD(state->fd), state->driver.drv_ptr->name);
-    erts_send_error_to_logger_nogl(dsbufp);
 
     if (on) {
 	/* Either fd-owner changed its mind about closing
 	 * or closed fd before stop_select callback and fd is now reused.
 	 * In either case stop_select should not be called.
-	 */	    
-	state->type = ERTS_EV_TYPE_NONE;
-	state->flags &= ~ERTS_EV_FLAG_USED;
-	if (state->driver.drv_ptr->handle) {
-	    erts_ddll_dereference_driver(state->driver.drv_ptr->handle);
-	}
-	state->driver.drv_ptr = NULL;
+	 */
+        cancel = 1;
     }
     else if ((mode & ERL_DRV_USE_NO_CALLBACK) == ERL_DRV_USE) {
 	Port *prt = erts_drvport2port(ix);
-	erts_driver_t* drv_ptr = prt != ERTS_INVALID_ERL_DRV_PORT ? prt->drv_ptr : NULL;
-	if (drv_ptr && drv_ptr != state->driver.drv_ptr) {
-	    /* Some other driver wants the stop_select callback */
-	    if (state->driver.drv_ptr->handle) {
-		erts_ddll_dereference_driver(state->driver.drv_ptr->handle);
-	    }
-	    if (drv_ptr->handle) {
-		erts_ddll_reference_referenced_driver(drv_ptr->handle);
-	    }
-	    state->driver.drv_ptr = drv_ptr;
-	}    
+	if (prt == ERTS_INVALID_ERL_DRV_PORT
+            || prt->drv_ptr != state->driver.stop.drv_ptr) {
+	    /* Some other driver or nif wants the stop_select callback */
+            cancel = 1;
+        }
+    }
+
+    if (cancel) {
+        erts_dsprintf(dsbufp, "called before stop_select was called for driver '%s'\n",
+                      state->driver.stop.drv_ptr->name);
+        if (state->driver.stop.drv_ptr->handle) {
+            erts_ddll_dereference_driver(state->driver.stop.drv_ptr->handle);
+        }
+        state->type = ERTS_EV_TYPE_NONE;
+        state->flags &= ~ERTS_EV_FLAG_USED;
+        state->driver.stop.drv_ptr = NULL;
+    }
+    else {
+        erts_dsprintf(dsbufp, "ignored repeated call\n");
+    }
+    erts_send_error_to_logger_nogl(dsbufp);
+}
+
+static void
+steal_pending_stop_nif(erts_dsprintf_buf_t *dsbufp, ErlNifResource* resource,
+                       ErtsDrvEventState *state, int mode, int on)
+{
+    int cancel = 0;
+
+    ASSERT(state->type == ERTS_EV_TYPE_STOP_NIF);
+    ASSERT(state->driver.stop.resource);
+
+    if (on) {
+        ASSERT(mode & (ERL_NIF_SELECT_READ | ERL_NIF_SELECT_WRITE));
+        /* Either fd-owner changed its mind about closing
+         * or closed fd before stop callback and fd is now reused.
+         * In either case, stop should not be called.
+         */
+        cancel = 1;
     }
+    else if ((mode & ERL_DRV_USE_NO_CALLBACK) == ERL_DRV_USE
+             && resource != state->driver.stop.resource) {
+        /* Some driver or other resource wants the stop callback */
+        cancel = 1;
+    }
+
+    if (cancel) {
+        ErlNifResourceType* rt = state->driver.stop.resource->type;
+        erts_dsprintf(dsbufp, "called before stop was called for NIF resource %T:%T\n",
+                      rt->module, rt->name);
+
+        enif_release_resource(state->driver.stop.resource);
+        state->type = ERTS_EV_TYPE_NONE;
+        state->flags &= ~ERTS_EV_FLAG_USED;
+        state->driver.stop.resource = NULL;
+    }
+    else {
+        erts_dsprintf(dsbufp, "ignored repeated call\n");
+    }
+    erts_send_error_to_logger_nogl(dsbufp);
 
 }
 
@@ -1557,6 +2053,48 @@ oready(Eterm id, ErtsDrvEventState *state, erts_aint_t current_cio_time)
     }
 }
 
+static ERTS_INLINE void
+send_event_tuple(struct erts_nif_select_event* e, ErlNifResource* resource,
+                 Eterm event_atom)
+{
+    Process* rp = erts_proc_lookup(e->pid);
+    ErtsProcLocks rp_locks = 0;
+    ErtsMessage* mp;
+    ErlOffHeap* ohp;
+    ErtsBinary* bin;
+    Eterm* hp;
+    Uint hsz = 5 + PROC_BIN_SIZE + REF_THING_SIZE; /* {select, Resource, Ref, EventAtom} */
+    Eterm resource_term, ref_term, tuple;
+
+    if (!rp) {
+        erts_fprintf(stderr, "SVERK: Process %T not alive for msg %T\n", e->pid, event_atom);
+        return;
+    }
+
+    bin = ERTS_MAGIC_BIN_FROM_UNALIGNED_DATA(resource);
+
+    mp = erts_alloc_message_heap(rp, &rp_locks, hsz, &hp, &ohp);
+
+    resource_term = erts_mk_magic_binary_term(&hp, ohp, &bin->binary);
+    if (is_value(e->immed)) {
+        ASSERT(is_immed(e->immed));
+        ref_term = e->immed;
+    }
+    else {
+        write_ref_thing(hp, e->refn[0], e->refn[1], e->refn[2]);
+        ref_term = make_internal_ref(hp);
+    }
+    hp += REF_THING_SIZE;
+    tuple = TUPLE4(hp, am_select, resource_term, ref_term, event_atom);
+
+    ERL_MESSAGE_TOKEN(mp) = am_undefined;
+    erts_queue_message(rp, rp_locks, mp, tuple, am_system);
+
+    if (rp_locks)
+        erts_smp_proc_unlock(rp, rp_locks);
+}
+
+
 #if ERTS_CIO_HAVE_DRV_EVENT
 static ERTS_INLINE void
 eready(Eterm id, ErtsDrvEventState *state, ErlDrvEventData event_data,
@@ -1602,6 +2140,8 @@ ERTS_CIO_EXPORT(erts_check_io_interrupt_timed)(int set,
     ERTS_CIO_POLL_INTR_TMD(pollset.ps, set, timeout_time);
 }
 
+#define ERTS_NIF_DELAYED_DESELECT 20
+
 void
 ERTS_CIO_EXPORT(erts_check_io)(int do_wait)
 {
@@ -1635,7 +2175,8 @@ ERTS_CIO_EXPORT(erts_check_io)(int do_wait)
     current_cio_time++;
     erts_smp_atomic_set_relb(&erts_check_io_time, current_cio_time);
 
-    check_cleanup_active_fds(current_cio_time);
+    check_cleanup_active_fds(current_cio_time,
+                             timeout_time != ERTS_POLL_NO_TIMEOUT);
 
 #ifdef ERTS_ENABLE_LOCK_CHECK
     erts_lc_check_exact(NULL, 0); /* No locks should be locked */
@@ -1741,6 +2282,69 @@ ERTS_CIO_EXPORT(erts_check_io)(int do_wait)
 	    break;
 	}
 
+        case ERTS_EV_TYPE_NIF: { /* Requested via enif_select()... */
+            struct erts_nif_select_event in = {NIL};
+            struct erts_nif_select_event out = {NIL};
+            ErlNifResource* resource;
+            ErtsPollEvents revents = pollres[i].events;
+
+            if (revents & ERTS_POLL_EV_ERR) {
+                /*
+                 * Handle error events by triggering all in/out events
+                 * that the NIF has selected.
+                 * We *do not* want to send a message that corresponds
+		 * to an event not selected.
+                 */
+                revents = state->events;
+            }
+            else {
+                revents &= (state->events | ERTS_POLL_EV_NVAL);
+            }
+
+            if (revents & (ERTS_POLL_EV_IN|ERTS_POLL_EV_OUT)) {
+                if (revents & ERTS_POLL_EV_OUT) {
+                    if (is_not_nil(state->driver.nif->out.pid)) {
+                        out = state->driver.nif->out;
+                        resource = state->driver.stop.resource;
+                        state->driver.nif->out.ddeselect_cnt = ERTS_NIF_DELAYED_DESELECT;
+                        state->driver.nif->out.pid = NIL;
+                        add_active_fd(state->fd);
+                    }
+                    else {
+                        ASSERT(state->driver.nif->out.ddeselect_cnt >= 2);
+                        state->driver.nif->out.ddeselect_cnt--;
+                    }
+                }
+                if (revents & ERTS_POLL_EV_IN) {
+                    if (is_not_nil(state->driver.nif->in.pid)) {
+                        in = state->driver.nif->in;
+                        resource = state->driver.stop.resource;
+                        state->driver.nif->in.ddeselect_cnt = ERTS_NIF_DELAYED_DESELECT;
+                        state->driver.nif->in.pid = NIL;
+                        add_active_fd(state->fd);
+                    }
+                    else {
+                        ASSERT(state->driver.nif->in.ddeselect_cnt >= 2);
+                        state->driver.nif->in.ddeselect_cnt--;
+                    }
+                }
+            }
+            else if (revents & ERTS_POLL_EV_NVAL) {
+                abort();
+            }
+
+#ifdef ERTS_SMP
+            erts_smp_mtx_unlock(fd_mtx(fd));
+#endif
+            if (is_not_nil(in.pid)) {
+                send_event_tuple(&in, resource, am_ready_input);
+            }
+            if (is_not_nil(out.pid)) {
+                send_event_tuple(&out, resource, am_ready_output);
+            }
+            goto next_pollres_unlocked;
+        }
+
 #if ERTS_CIO_HAVE_DRV_EVENT
 	case ERTS_EV_TYPE_DRV_EV: { /* Requested via driver_event()... */
 	    ErlDrvEventData event_data;
@@ -1781,6 +2385,7 @@ ERTS_CIO_EXPORT(erts_check_io)(int do_wait)
 #ifdef ERTS_SMP
 	erts_smp_mtx_unlock(fd_mtx(fd));
 #endif
+        next_pollres_unlocked:;
     }
 
     erts_smp_atomic_set_nob(&pollset.in_poll_wait, 0);
@@ -2306,6 +2911,39 @@ static void doit_erts_check_io_debug(void *vstate, void *vcounters)
 		}
 	    }
 	}
+        else if (state->type == ERTS_EV_TYPE_NIF) {
+            ErlNifResource* r;
+            erts_printf("enif_select ");
+
+#ifdef ERTS_SYS_CONTINOUS_FD_NUMBERS
+            if (internal) {
+                erts_printf("internal ");
+                err = 1;
+            }
+
+            if (cio_events == ep_events) {
+                erts_printf("ev=");
+                if (print_events(cio_events) != 0)
+                    err = 1;
+            }
+            else {
+                err = 1;
+                erts_printf("cio_ev=");
+                print_events(cio_events);
+                erts_printf(" ep_ev=");
+                print_events(ep_events);
+            }
+#else
+            if (print_events(cio_events) != 0)
+                err = 1;
+#endif
+            erts_printf(" inpid=%T dd_cnt=%b32d", state->driver.nif->in.pid,
+                        state->driver.nif->in.ddeselect_cnt);
+            erts_printf(" outpid=%T dd_cnt=%b32d", state->driver.nif->out.pid,
+                        state->driver.nif->out.ddeselect_cnt);
+            r = state->driver.stop.resource;
+            erts_printf(" resource=%p(%T:%T)", r, r->type->module, r->type->name);
+        }
 #if ERTS_CIO_HAVE_DRV_EVENT
 	else if (state->type == ERTS_EV_TYPE_DRV_EV) {
 	    Eterm id;
@@ -2362,11 +3000,12 @@ static void doit_erts_check_io_debug(void *vstate, void *vcounters)
 	    erts_printf("control_type=%d ", (int)state->type);
 #ifdef ERTS_SYS_CONTINOUS_FD_NUMBERS
 	    if (cio_events == ep_events) {
-		erts_printf("ev=0x%b32x", (Uint32) cio_events);
+                erts_printf("ev=");
+                print_events(cio_events);
 	    }
 	    else {
-		erts_printf("cio_ev=0x%b32x", (Uint32) cio_events);
-		erts_printf(" ep_ev=0x%b32x", (Uint32) ep_events);
+		erts_printf("cio_ev="); print_events(cio_events);
+		erts_printf(" ep_ev="); print_events(ep_events);
 	    }
 #else
 	    erts_printf("ev=0x%b32x", (Uint32) cio_events);
@@ -2395,7 +3034,7 @@ ERTS_CIO_EXPORT(erts_check_io_debug)(ErtsCheckIoDebugInfo *ciodip)
 #if ERTS_CIO_HAVE_DRV_EVENT
     null_des.driver.event = NULL;
 #endif
-    null_des.driver.drv_ptr = NULL;
+    null_des.driver.stop.drv_ptr = NULL;
     null_des.events = 0;
     null_des.remove_cnt = 0;
     null_des.type = ERTS_EV_TYPE_NONE;
diff --git a/erts/emulator/sys/common/erl_check_io.h b/erts/emulator/sys/common/erl_check_io.h
index 14f1ea3f43..242e7cfcf5 100644
--- a/erts/emulator/sys/common/erl_check_io.h
+++ b/erts/emulator/sys/common/erl_check_io.h
@@ -34,6 +34,8 @@
 
 int driver_select_kp(ErlDrvPort, ErlDrvEvent, int, int);
 int driver_select_nkp(ErlDrvPort, ErlDrvEvent, int, int);
+int enif_select_kp(ErlNifEnv*, ErlNifEvent, enum ErlNifSelectFlags, void*, Eterm);
+int enif_select_nkp(ErlNifEnv*, ErlNifEvent, enum ErlNifSelectFlags, void*, Eterm);
 int driver_event_kp(ErlDrvPort, ErlDrvEvent, ErlDrvEventData);
 int driver_event_nkp(ErlDrvPort, ErlDrvEvent, ErlDrvEventData);
 Uint erts_check_io_size_kp(void);
@@ -136,4 +138,20 @@ typedef struct {
     ErtsIoTask iniotask;
     ErtsIoTask outiotask;
 } ErtsDrvSelectDataState;
+
+struct erts_nif_select_event {
+    Eterm pid;
+    Eterm immed;
+    Uint32 refn[ERTS_REF_NUMBERS];
+    Sint32 ddeselect_cnt; /* 0:  No delayed deselect in progress
+                           * 1:  Do deselect before next poll
+                           * >1: Countdown of ignored events
+                           */
+};
+
+typedef struct {
+    struct erts_nif_select_event in;
+    struct erts_nif_select_event out;
+} ErtsNifSelectDataState;
+
 #endif /* #ifndef ERL_CHECK_IO_INTERNAL__ */
diff --git a/erts/emulator/sys/common/erl_poll.c b/erts/emulator/sys/common/erl_poll.c
index b8a28bcc18..0c4df3e13a 100644
--- a/erts/emulator/sys/common/erl_poll.c
+++ b/erts/emulator/sys/common/erl_poll.c
@@ -3030,6 +3030,7 @@ ERTS_POLL_EXPORT(erts_poll_get_selected_events)(ErtsPollSet ps,
 	    ev[fd] = 0;
 	else {
 	    ev[fd] = ps->fds_status[fd].events;
+            ASSERT(ps->fds_status[fd].used_events == ev[fd]);
             if (
 #if ERTS_POLL_USE_WAKEUP_PIPE
                 fd == ps->wake_fds[0] || fd == ps->wake_fds[1] ||
diff --git a/erts/emulator/sys/unix/sys.c b/erts/emulator/sys/unix/sys.c
index 4b2edace0a..789b455f2d 100644
--- a/erts/emulator/sys/unix/sys.c
+++ b/erts/emulator/sys/unix/sys.c
@@ -161,6 +161,7 @@ int erts_use_kernel_poll = 0;
 
 struct {
     int (*select)(ErlDrvPort, ErlDrvEvent, int, int);
+    int (*enif_select)(ErlNifEnv*, ErlNifEvent, enum ErlNifSelectFlags, void*, Eterm);
     int (*event)(ErlDrvPort, ErlDrvEvent, ErlDrvEventData);
     void (*check_io_as_interrupt)(void);
     void (*check_io_interrupt)(int);
@@ -184,6 +185,13 @@ driver_event(ErlDrvPort port, ErlDrvEvent event, ErlDrvEventData event_data)
     return (*io_func.event)(port, event, event_data);
 }
 
+int enif_select(ErlNifEnv* env, ErlNifEvent event,
+                enum ErlNifSelectFlags flags, void* obj, Eterm ref)
+{
+    return (*io_func.enif_select)(env, event, flags, obj, ref);
+}
+
+
 Eterm erts_check_io_info(void *p)
 {
     return (*io_func.info)(p);
@@ -201,6 +209,7 @@ init_check_io(void)
 {
     if (erts_use_kernel_poll) {
 	io_func.select			= driver_select_kp;
+        io_func.enif_select		= enif_select_kp;
 	io_func.event			= driver_event_kp;
 #ifdef ERTS_POLL_NEED_ASYNC_INTERRUPT_SUPPORT
 	io_func.check_io_as_interrupt	= erts_check_io_async_sig_interrupt_kp;
@@ -216,6 +225,7 @@ init_check_io(void)
     }
     else {
 	io_func.select			= driver_select_nkp;
+        io_func.enif_select		= enif_select_nkp;
 	io_func.event			= driver_event_nkp;
 #ifdef ERTS_POLL_NEED_ASYNC_INTERRUPT_SUPPORT
 	io_func.check_io_as_interrupt	= erts_check_io_async_sig_interrupt_nkp;
diff --git a/erts/emulator/test/nif_SUITE.erl b/erts/emulator/test/nif_SUITE.erl
index 0d3910b2e2..8c761202d6 100644
--- a/erts/emulator/test/nif_SUITE.erl
+++ b/erts/emulator/test/nif_SUITE.erl
@@ -31,6 +31,7 @@
 	 init_per_testcase/2, end_per_testcase/2,
          basic/1, reload_error/1, upgrade/1, heap_frag/1,
          t_on_load/1,
+         select/1,
          hipe/1,
 	 types/1, many_args/1, binaries/1, get_string/1, get_atom/1,
 	 maps/1,
@@ -64,6 +65,7 @@ all() ->
     [{group, G} || G <- api_groups()]
         ++
     [reload_error, heap_frag, types, many_args,
+     select,
      hipe,
      binaries, get_string, get_atom, maps, api_macros, from_array,
      iolist_as_binary, resource, resource_binary,
@@ -434,6 +436,33 @@ t_on_load(Config) when is_list(Config) ->
     verify_tmpmem(TmpMem),
     ok.
 
+-define(ERL_NIF_SELECT_READ, (1 bsl 0)).
+-define(ERL_NIF_SELECT_WRITE, (1 bsl 1)).
+-define(ERL_NIF_SELECT_STOP, (1 bsl 2)).
+
+select(Config) when is_list(Config) ->
+    ensure_lib_loaded(Config),
+
+    Ref = make_ref(),
+    {R,W} = pipe_nif(),
+    ok = write_nif(W, <<"hej">>),
+    <<"hej">> = read_nif(R, 3),
+    eagain = read_nif(R, 3),
+    0 = select_nif(R,?ERL_NIF_SELECT_READ,R,Ref),
+    [] = flush(),
+    ok = write_nif(W, <<"hej">>),
+    [{select, R, Ref, ready_input}] = flush(),
+    <<"hej">> = read_nif(R, 3),
+
+    %% To be extended...
+
+    0 = select_nif(R,?ERL_NIF_SELECT_STOP,R,Ref),
+    0 = select_nif(W,?ERL_NIF_SELECT_STOP,W,Ref),
+    timer:sleep(10),
+    true = is_closed_nif(R),
+    true = is_closed_nif(W),
+    ok.
+
 hipe(Config) when is_list(Config) ->
     Data = proplists:get_value(data_dir, Config),
     Priv = proplists:get_value(priv_dir, Config),
@@ -1910,6 +1939,15 @@ call(Pid,Cmd) ->
 receive_any() ->
     receive M -> M end.	     
 
+flush() ->
+    flush(10).
+flush(Timeout) ->
+    receive M ->
+            [M | flush(Timeout)]
+    after Timeout ->
+            []
+    end.
+
 repeat(0, _, Arg) ->
     Arg;
 repeat(N, Fun, Arg0) ->
@@ -2273,6 +2311,11 @@ term_to_binary_nif(_, _) -> ?nif_stub.
 binary_to_term_nif(_, _, _) -> ?nif_stub.
 port_command_nif(_, _) -> ?nif_stub.
 format_term_nif(_,_) -> ?nif_stub.
+select_nif(_,_,_,_) -> ?nif_stub.
+pipe_nif() -> ?nif_stub.
+write_nif(_,_) -> ?nif_stub.
+read_nif(_,_) -> ?nif_stub.
+is_closed_nif(_) -> ?nif_stub.
 
 %% maps
 is_map_nif(_) -> ?nif_stub.
diff --git a/erts/emulator/test/nif_SUITE_data/nif_SUITE.c b/erts/emulator/test/nif_SUITE_data/nif_SUITE.c
index 2c93891852..a4915b13c4 100644
--- a/erts/emulator/test/nif_SUITE_data/nif_SUITE.c
+++ b/erts/emulator/test/nif_SUITE_data/nif_SUITE.c
@@ -25,6 +25,8 @@
 #include <limits.h>
 #ifndef __WIN32__
 #include <unistd.h>
+#include <fcntl.h>
+#include <errno.h>
 #endif
 
 #include "nif_mod.h"
@@ -42,7 +44,9 @@ static ERL_NIF_TERM atom_second;
 static ERL_NIF_TERM atom_millisecond;
 static ERL_NIF_TERM atom_microsecond;
 static ERL_NIF_TERM atom_nanosecond;
-
+static ERL_NIF_TERM atom_eagain;
+static ERL_NIF_TERM atom_eof;
+static ERL_NIF_TERM atom_error;
 
 typedef struct
 {
@@ -102,6 +106,18 @@ struct binary_resource {
     unsigned size;
 };
 
+static ErlNifResourceType* fd_resource_type;
+static void fd_resource_dtor(ErlNifEnv* env, void* obj);
+static void fd_resource_stop(ErlNifEnv* env, void* obj);
+static ErlNifResourceTypeInit fd_rt_init = {
+    fd_resource_dtor,
+    fd_resource_stop
+};
+struct fd_resource {
+    int fd;
+};
+
+
 static int get_pointer(ErlNifEnv* env, ERL_NIF_TERM term, void** pp)
 {
     ErlNifBinary bin;
@@ -144,6 +160,9 @@ static int load(ErlNifEnv* env, void** priv_data, ERL_NIF_TERM load_info)
     msgenv_resource_type =  enif_open_resource_type(env,NULL,"nif_SUITE.msgenv",
 						    msgenv_dtor,
 						    ERL_NIF_RT_CREATE, NULL);
+    fd_resource_type =  enif_open_resource_type_x(env, "nif_SUITE.fd",
+                                                  &fd_rt_init,
+                                                  ERL_NIF_RT_CREATE, NULL);
     atom_false = enif_make_atom(env,"false");
     atom_true = enif_make_atom(env,"true");
     atom_self = enif_make_atom(env,"self");
@@ -154,6 +173,9 @@ static int load(ErlNifEnv* env, void** priv_data, ERL_NIF_TERM load_info)
     atom_millisecond = enif_make_atom(env,"millisecond");
     atom_microsecond = enif_make_atom(env,"microsecond");
     atom_nanosecond = enif_make_atom(env,"nanosecond");
+    atom_eagain = enif_make_atom(env, "eagain");
+    atom_eof = enif_make_atom(env, "eof");
+    atom_error = enif_make_atom(env, "error");
 
     *priv_data = data;
     return 0;
@@ -2010,6 +2032,165 @@ static ERL_NIF_TERM format_term(ErlNifEnv* env, int argc, const ERL_NIF_TERM arg
 }
 
 
+static int get_fd(ErlNifEnv* env, ERL_NIF_TERM term, ErlNifEvent* fd)
+{
+    struct fd_resource* rsrc;
+
+    if (!enif_get_resource(env, term, fd_resource_type, (void**)&rsrc)) {
+        return 0;
+    }
+    *fd = rsrc->fd;
+    return 1;
+}
+
+static ERL_NIF_TERM select_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
+{
+    ErlNifEvent e;
+    enum ErlNifSelectFlags mode;
+    void* obj;
+    ERL_NIF_TERM ref;
+    int retval;
+
+    if (!get_fd(env, argv[0], &e)
+        || !enif_get_uint(env, argv[1], &mode)
+        || !enif_get_resource(env, argv[2], fd_resource_type, &obj))
+    {
+        return enif_make_badarg(env);
+    }
+
+    ref = argv[3];
+
+    retval = enif_select(env, e, mode, obj, ref);
+
+    return enif_make_int(env, retval);
+}
+
+static ERL_NIF_TERM pipe_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
+{
+    struct fd_resource* read_rsrc;
+    struct fd_resource* write_rsrc;
+    ERL_NIF_TERM read_fd, write_fd;
+    unsigned char *inp, *outp;
+    int fds[2], flags;
+
+    if (pipe(fds) < 0)
+        return enif_make_string(env, "pipe failed", ERL_NIF_LATIN1);
+
+    if ((flags = fcntl(fds[0], F_GETFL, 0)) < 0
+        || fcntl(fds[0], F_SETFL, flags|O_NONBLOCK) < 0
+        || (flags = fcntl(fds[1], F_GETFL, 0)) < 0
+        || fcntl(fds[1], F_SETFL, flags|O_NONBLOCK) < 0) {
+        close(fds[0]);
+        close(fds[1]);
+        return enif_make_string(env, "fcntl failed on pipe", ERL_NIF_LATIN1);
+    }
+
+    read_rsrc  = enif_alloc_resource(fd_resource_type, sizeof(struct fd_resource));
+    write_rsrc = enif_alloc_resource(fd_resource_type, sizeof(struct fd_resource));
+    read_rsrc->fd  = fds[0];
+    write_rsrc->fd = fds[1];
+    read_fd  = enif_make_resource(env, read_rsrc);
+    write_fd = enif_make_resource(env, write_rsrc);
+    enif_release_resource(read_rsrc);
+    enif_release_resource(write_rsrc);
+
+    return enif_make_tuple2(env, read_fd, write_fd);
+}
+
+static ERL_NIF_TERM write_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
+{
+    ErlNifEvent fd;
+    ErlNifBinary bin;
+    int n, written = 0;
+
+    if (!get_fd(env, argv[0], &fd)
+        || !enif_inspect_binary(env, argv[1], &bin))
+        return enif_make_badarg(env);
+
+    for (;;) {
+        n = write(fd, bin.data + written, bin.size - written);
+        if (n >= 0) {
+            written += n;
+            if (written == bin.size) {
+                return atom_ok;
+            }
+        }
+        else if (errno == EAGAIN) {
+            return enif_make_tuple2(env, atom_eagain, enif_make_int(env, written));
+        }
+        else if (errno == EINTR) {
+            continue;
+        }
+        else {
+            return enif_make_tuple2(env, atom_error, enif_make_int(env, errno));
+        }
+    }
+}
+
+static ERL_NIF_TERM read_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
+{
+    ErlNifEvent fd;
+    unsigned char* buf;
+    int n, count, nread = 0;
+    ERL_NIF_TERM res;
+
+    if (!get_fd(env, argv[0], &fd)
+        || !enif_get_int(env, argv[1], &count) || count < 1)
+        return enif_make_badarg(env);
+
+    buf = enif_make_new_binary(env, count, &res);
+
+    for (;;) {
+        n = read(fd, buf, count);
+        if (n > 0) {
+            if (n < count) {
+                res = enif_make_sub_binary(env, res, 0, n);
+            }
+            return res;
+        }
+        else if (n == 0) {
+            return atom_eof;
+        }
+        else if (errno == EAGAIN) {
+            return atom_eagain;
+        }
+        else if (errno == EINTR) {
+            continue;
+        }
+        else {
+            return enif_make_tuple2(env, atom_error, enif_make_int(env, errno));
+        }
+    }
+}
+
+static ERL_NIF_TERM is_closed_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
+{
+    ErlNifEvent fd;
+
+    if (!get_fd(env, argv[0], &fd))
+        return enif_make_badarg(env);
+
+    return fd < 0 ? atom_true : atom_false;
+}
+
+static void fd_resource_dtor(ErlNifEnv* env, void* obj)
+{
+    struct fd_resource* rsrc = (struct fd_resource*)obj;
+    if (rsrc->fd >= 0)
+        close(rsrc->fd);
+}
+
+static void fd_resource_stop(ErlNifEnv* env, void* obj)
+{
+    struct fd_resource* rsrc = (struct fd_resource*)obj;
+    if (rsrc->fd >= 0) {
+        close(rsrc->fd);
+        rsrc->fd = -1;   /* thread safety ? */
+    }
+}
+
+
+
 static ErlNifFunc nif_funcs[] =
 {
     {"lib_version", 0, lib_version},
@@ -2086,7 +2267,12 @@ static ErlNifFunc nif_funcs[] =
     {"term_to_binary_nif", 2, term_to_binary},
     {"binary_to_term_nif", 3, binary_to_term},
     {"port_command_nif", 2, port_command},
-    {"format_term_nif", 2, format_term}
+    {"format_term_nif", 2, format_term},
+    {"select_nif", 4, select_nif},
+    {"pipe_nif", 0, pipe_nif},
+    {"write_nif", 2, write_nif},
+    {"read_nif", 2, read_nif},
+    {"is_closed_nif", 1, is_closed_nif}
 };
 
 ERL_NIF_INIT(nif_SUITE,nif_funcs,load,NULL,upgrade,unload)