ose: Add module that allows interaction with any OSE process

The interface of this module is made to be as generic as possible
in order for other IPC mechanisms to mimic it and allow porting of
code between different os:es.

1 files changed, 884 insertions, 0 deletions

diff --git a/erts/emulator/drivers/ose/ose_signal_drv.c b/erts/emulator/drivers/ose/ose_signal_drv.c
new file mode 100644
index 0000000000..acf09f748e
--- /dev/null
+++ b/erts/emulator/drivers/ose/ose_signal_drv.c
@@ -0,0 +1,884 @@
+/*
+ * %CopyrightBegin%
+ *
+ * Copyright Ericsson AB 2013-2013. All Rights Reserved.
+ *
+ * The contents of this file are subject to the Erlang Public License,
+ * Version 1.1, (the "License"); you may not use this file except in
+ * compliance with the License. You should have received a copy of the
+ * Erlang Public License along with this software. If not, it can be
+ * retrieved online at http://www.erlang.org/.
+ *
+ * Software distributed under the License is distributed on an "AS IS"
+ * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
+ * the License for the specific language governing rights and limitations
+ * under the License.
+ *
+ * %CopyrightEnd%
+ */
+#ifdef HAVE_CONFIG_H
+#  include "config.h"
+#endif
+
+#include "errno.h"
+#include "stdio.h"
+#include "string.h"
+#include "stddef.h"
+
+#include "sys.h"
+#include "erl_driver.h"
+#include "ose.h"
+#include "ose_spi/ose_spi.h"
+
+#define DEBUG_ATTACH   0
+#define DEBUG_HUNT     0
+#define DEBUG_SEND     0
+#define DEBUG_LISTEN   0
+
+#if 0
+#define DEBUGP(FMT,...) printf(FMT, __VA_ARGS__)
+#else
+#define DEBUGP(FMT,...)
+#endif
+
+#if DEBUG_ATTACH
+#define DEBUGP_ATTACH(...) DEBUGP( __VA_ARGS__)
+#else
+#define DEBUGP_ATTACH(...)
+#endif
+
+#if DEBUG_HUNT
+#define DEBUGP_HUNT(...) DEBUGP( __VA_ARGS__)
+#else
+#define DEBUGP_HUNT(...)
+#endif
+
+#if DEBUG_LISTEN
+#define DEBUGP_LISTEN(...) DEBUGP( __VA_ARGS__)
+#else
+#define DEBUGP_LISTEN(...)
+#endif
+
+#if DEBUG_SEND
+#define DEBUGP_SEND(...) DEBUGP( __VA_ARGS__)
+#else
+#define DEBUGP_SEND(...)
+#endif
+
+
+#define DRIVER_NAME "ose_signal_drv"
+#define GET_SPID        1
+#define GET_NAME        2
+#define HUNT          100
+#define DEHUNT        101
+#define ATTACH        102
+#define DETACH        103
+#define SEND          104
+#define SEND_W_S      105
+#define LISTEN        106
+#define OPEN          200
+
+#define REF_SEGMENT_SIZE 8
+
+struct async {
+  SIGSELECT signo;
+  ErlDrvTermData port;
+  ErlDrvTermData proc;
+  PROCESS spid;
+  PROCESS target;
+  Uint32 ref;
+};
+
+/**
+ * OSE signals
+ **/
+union SIGNAL {
+  SIGSELECT signo;
+  struct async async;
+};
+
+/**
+ * The driver's context
+ **/
+typedef struct _driver_context {
+  ErlDrvPort port;
+  PROCESS spid;
+  ErlDrvEvent perm_events[2];
+  ErlDrvEvent *events;
+  Uint32 event_cnt;
+  Uint32 ref;
+  Uint32 *outstanding_refs;
+  Uint32 outstanding_refs_max;
+  Uint32 outstanding_refs_cnt;
+} driver_context_t;
+
+/**
+ * Global variables
+ **/
+static ErlDrvTermData a_ok;
+static ErlDrvTermData a_error;
+static ErlDrvTermData a_enomem;
+static ErlDrvTermData a_enoent;
+static ErlDrvTermData a_badarg;
+static ErlDrvTermData a_mailbox_up;
+static ErlDrvTermData a_mailbox_down;
+static ErlDrvTermData a_ose_drv_reply;
+static ErlDrvTermData a_message;
+static PROCESS proxy_proc;
+
+
+/**
+ * Serialize/unserialize unsigned 32-bit values
+ **/
+static char *put_u32(unsigned int value, char *ptr) {
+  *ptr++ = (value & 0xff000000) >> 24;
+  *ptr++ = (value & 0x00ff0000) >> 16;
+  *ptr++ = (value & 0x0000ff00) >> 8;
+  *ptr++ = (value & 0xff);
+
+  return ptr;
+}
+
+static unsigned int get_u32(char *ptr) {
+  unsigned int result = 0;
+  result += (ptr[0] & 0xff) << 24;
+  result += (ptr[1] & 0xff) << 16;
+  result += (ptr[2] & 0xff) << 8;
+  result += (ptr[3] & 0xff);
+
+  return result;
+}
+
+
+/* Stolen from efile_drv.c */
+
+/* char EV_CHAR_P(ErlIOVec *ev, int p, int q) */
+#define EV_CHAR_P(ev, p, q)                   \
+    (((char *)(ev)->iov[(q)].iov_base) + (p))
+
+/* int EV_GET_CHAR(ErlIOVec *ev, char *p, int *pp, int *qp) */
+#define EV_GET_CHAR(ev, p, pp, qp) ev_get_char(ev, p ,pp, qp)
+static int
+ev_get_char(ErlIOVec *ev, char *p, int *pp, int *qp) {
+  if (*(pp)+1 <= (ev)->iov[*(qp)].iov_len) {
+    *(p) = *EV_CHAR_P(ev, *(pp), *(qp));
+    if (*(pp)+1 < (ev)->iov[*(qp)].iov_len)
+      *(pp) = *(pp)+1;
+    else {
+      (*(qp))++;
+      *pp = 0;
+    }
+    return !0;
+  }
+  return 0;
+}
+
+/* Uint32 EV_UINT32(ErlIOVec *ev, int p, int q)*/
+#define EV_UINT32(ev, p, q) \
+    ((Uint32) *(((unsigned char *)(ev)->iov[(q)].iov_base) + (p)))
+
+/* int EV_GET_UINT32(ErlIOVec *ev, Uint32 *p, int *pp, int *qp) */
+#define EV_GET_UINT32(ev, p, pp, qp) ev_get_uint32(ev,(Uint32*)(p),pp,qp)
+static int
+ev_get_uint32(ErlIOVec *ev, Uint32 *p, int *pp, int *qp) {
+  if (*(pp)+4 <= (ev)->iov[*(qp)].iov_len) {
+    *(p) = (EV_UINT32(ev, *(pp),   *(qp)) << 24)
+      | (EV_UINT32(ev, *(pp)+1, *(qp)) << 16)
+      | (EV_UINT32(ev, *(pp)+2, *(qp)) << 8)
+      | (EV_UINT32(ev, *(pp)+3, *(qp)));
+    if (*(pp)+4 < (ev)->iov[*(qp)].iov_len)
+      *(pp) = *(pp)+4;
+    else {
+      (*(qp))++;
+      *pp = 0;
+    }
+    return !0;
+  }
+  return 0;
+}
+
+/**
+ * Convinience macros
+ **/
+#define send_response(port,output) erl_drv_send_term(driver_mk_port(port),\
+    driver_caller(port), output, sizeof(output) / sizeof(output[0]));
+
+void iov_memcpy(void *dest,ErlIOVec *ev,int ind,int off);
+void iov_memcpy(void *dest,ErlIOVec *ev,int ind,int off) {
+  int i;
+  memcpy(dest,ev->iov[ind].iov_base+off,ev->iov[ind].iov_len-off);
+  for (i = ind+1; i < ev->vsize; i++)
+    memcpy(dest,ev->iov[i].iov_base,ev->iov[i].iov_len);
+}
+
+/**
+ * Reference handling
+ **/
+
+static int add_reference(driver_context_t *ctxt, Uint32 ref) {
+
+  /*
+   * Premature optimizations may be evil, but they sure are fun.
+   */
+
+  if (ctxt->outstanding_refs == NULL) {
+    /* First ref to be ignored */
+    ctxt->outstanding_refs = driver_alloc(REF_SEGMENT_SIZE*sizeof(Uint32));
+    if (!ctxt->outstanding_refs)
+      return 1;
+
+    memset(ctxt->outstanding_refs,0,REF_SEGMENT_SIZE*sizeof(Uint32));
+    ctxt->outstanding_refs_max += REF_SEGMENT_SIZE;
+    ctxt->outstanding_refs[ctxt->outstanding_refs_cnt++] = ref;
+  } else if (ctxt->outstanding_refs_cnt == ctxt->outstanding_refs_max) {
+    /* Expand ref array */
+    Uint32 *new_array;
+    ctxt->outstanding_refs_max += REF_SEGMENT_SIZE;
+    new_array = driver_realloc(ctxt->outstanding_refs,
+			       ctxt->outstanding_refs_max*sizeof(Uint32));
+
+    if (!new_array) {
+      ctxt->outstanding_refs_max -= REF_SEGMENT_SIZE;
+      return 1;
+    }
+
+    ctxt->outstanding_refs = new_array;
+
+    memset(ctxt->outstanding_refs+ctxt->outstanding_refs_cnt,0,
+	   REF_SEGMENT_SIZE*sizeof(Uint32));
+    ctxt->outstanding_refs[ctxt->outstanding_refs_cnt++] = ref;
+
+  } else {
+    /* Find an empty slot:
+     *   First we try current index,
+     *   then we scan for a slot.
+     */
+    if (!ctxt->outstanding_refs[ctxt->outstanding_refs_cnt]) {
+      ctxt->outstanding_refs[ctxt->outstanding_refs_cnt++] = ref;
+    } else {
+      int i;
+      ASSERT(ctxt->outstanding_refs_cnt < ctxt->outstanding_refs_max);
+      for (i = 0; i < ctxt->outstanding_refs_max; i++)
+	if (!ctxt->outstanding_refs[i])
+	  break;
+      ASSERT(ctxt->outstanding_refs[i] == 0);
+      ctxt->outstanding_refs[i] = ref;
+      ctxt->outstanding_refs_cnt++;
+    }
+  }
+  return 0;
+}
+
+/* Return 0 if removed, 1 if does not exist, */
+static int remove_reference(driver_context_t *ctxt, Uint32 ref) {
+  int i,j;
+
+  if (ctxt->outstanding_refs_max == 0 && ctxt->outstanding_refs_cnt == 0) {
+    ASSERT(ctxt->outstanding_refs == NULL);
+    return 1;
+  }
+
+  for (i = 0; i < ctxt->outstanding_refs_max; i++) {
+    if (ctxt->outstanding_refs[i] == ref) {
+      ctxt->outstanding_refs[i] = 0;
+      ctxt->outstanding_refs_cnt--;
+      i = -1;
+      break;
+    }
+  }
+
+  if (i != -1)
+    return 1;
+
+  if (ctxt->outstanding_refs_cnt == 0) {
+    driver_free(ctxt->outstanding_refs);
+    ctxt->outstanding_refs = NULL;
+    ctxt->outstanding_refs_max = 0;
+  } else if (ctxt->outstanding_refs_cnt == (ctxt->outstanding_refs_max - REF_SEGMENT_SIZE)) {
+    Uint32 *new_array;
+    for (i = 0, j = 0; i < ctxt->outstanding_refs_cnt; i++) {
+      if (ctxt->outstanding_refs[i] == 0) {
+	for (j = i+1; j < ctxt->outstanding_refs_max; j++)
+	  if (ctxt->outstanding_refs[j]) {
+	    ctxt->outstanding_refs[i] = ctxt->outstanding_refs[j];
+	    ctxt->outstanding_refs[j] = 0;
+	    break;
+	  }
+      }
+    }
+    ctxt->outstanding_refs_max -= REF_SEGMENT_SIZE;
+    new_array = driver_realloc(ctxt->outstanding_refs,
+			       ctxt->outstanding_refs_max*sizeof(Uint32));
+    if (!new_array) {
+      ctxt->outstanding_refs_max += REF_SEGMENT_SIZE;
+      return 2;
+    }
+
+    ctxt->outstanding_refs = new_array;
+
+  }
+
+  return 0;
+}
+
+/**
+ * The OSE proxy process. This only handles ERTS_SIGNAL_OSE_DRV_ATTACH.
+ * The process is needed because signals triggered by attach ignore
+ * redir tables.
+ *
+ * We have one global proxy process to save memory. An attempt to make each
+ * port phantom into a proxy was made, but that used way to much memory.
+ */
+static OS_PROCESS(driver_proxy_process) {
+  SIGSELECT sigs[] = {1,ERTS_SIGNAL_OSE_DRV_ATTACH};
+  PROCESS master = 0;
+
+  while (1) {
+    union SIGNAL *sig = receive(sigs);
+
+    if (sig->signo == ERTS_SIGNAL_OSE_DRV_ATTACH) {
+
+      /* The first message is used to determine who to send messages to. */
+      if (master == 0)
+	master = sender(&sig);
+
+      if (sig->async.target == 0) {
+	PROCESS from = sender(&sig);
+	restore(sig);
+	DEBUGP_ATTACH("0x%x: got attach 0x%x, sending to 0x%x\n",
+		      current_process(),from,master);
+	sig->async.target = from;
+	send(&sig,master);
+      } else {
+	PROCESS target = sig->async.target;
+	restore(sig);
+	sig->async.target = 0;
+	DEBUGP_ATTACH("0x%x: doing attach on 0x%x\n",current_process(),target);
+	attach(&sig,target);
+      }
+    }
+  }
+}
+
+/**
+ * Init routine for the driver
+ **/
+static int drv_init(void) {
+
+  a_ok = driver_mk_atom("ok");
+  a_error = driver_mk_atom("error");
+  a_enomem = driver_mk_atom("enomem");
+  a_enoent = driver_mk_atom("enoent");
+  a_badarg = driver_mk_atom("badarg");
+  a_mailbox_up = driver_mk_atom("mailbox_up");
+  a_mailbox_down = driver_mk_atom("mailbox_down");
+  a_ose_drv_reply = driver_mk_atom("ose_drv_reply");
+  a_message = driver_mk_atom("message");
+
+  proxy_proc = create_process(get_ptype(current_process()),
+			      "ose_signal_driver_proxy",
+			      driver_proxy_process, 10000,
+			      get_pri(current_process()),
+			      0, 0, NULL, 0, 0);
+
+#ifdef DEBUG
+  efs_clone(proxy_proc);
+#endif
+  start(proxy_proc);
+
+  return 0;
+}
+
+/**
+ * Start routine for the driver
+ **/
+static ErlDrvData drv_start(ErlDrvPort port, char *command)
+{
+  driver_context_t *ctxt = driver_alloc(sizeof(driver_context_t));
+
+  ctxt->perm_events[0] = NULL;
+  ctxt->perm_events[1] = NULL;
+
+  ctxt->spid = 0;
+  ctxt->port = port;
+  ctxt->event_cnt = 0;
+  ctxt->events = NULL;
+  ctxt->ref = 0;
+  ctxt->outstanding_refs = NULL;
+  ctxt->outstanding_refs_max = 0;
+  ctxt->outstanding_refs_cnt = 0;
+
+
+  /* Set the communication protocol to Erlang to be binary */
+  set_port_control_flags(port, PORT_CONTROL_FLAG_BINARY);
+
+  /* Everything ok */
+  return (ErlDrvData)ctxt;
+}
+
+/**
+ * Stop routine for the driver
+ **/
+static void drv_stop(ErlDrvData driver_data)
+{
+  driver_context_t *ctxt = (driver_context_t *)driver_data;
+  int i;
+
+  /* HUNT + ATTACH */
+  if (ctxt->perm_events[0])
+    driver_select(ctxt->port, ctxt->perm_events[0],
+		  ERL_DRV_USE|ERL_DRV_READ, 0);
+  if (ctxt->perm_events[1])
+    driver_select(ctxt->port, ctxt->perm_events[1],
+		  ERL_DRV_USE|ERL_DRV_READ, 0);
+
+  for (i = 0; i < ctxt->event_cnt; i++) {
+    driver_select(ctxt->port, ctxt->events[i], ERL_DRV_USE|ERL_DRV_READ, 0);
+  }
+
+  if (ctxt->spid != 0)
+    kill_proc(ctxt->spid);
+  DEBUGP("0x%x: stopped\n",ctxt->spid);
+  if (ctxt->events)
+    driver_free(ctxt->events);
+  if (ctxt->outstanding_refs)
+    driver_free(ctxt->outstanding_refs);
+
+  driver_free(ctxt);
+}
+
+/**
+ * Output from Erlang
+ **/
+static void outputv(ErlDrvData driver_data, ErlIOVec *ev)
+{
+  driver_context_t *ctxt = (driver_context_t *)driver_data;
+  int p = 0, q = 1;
+  char cmd;
+
+  if (! EV_GET_CHAR(ev,&cmd,&p,&q)) {
+    ErlDrvTermData output[] = {
+      ERL_DRV_ATOM, a_ose_drv_reply,
+      ERL_DRV_PORT, driver_mk_port(ctxt->port),
+      ERL_DRV_ATOM, a_badarg,
+      ERL_DRV_TUPLE, 3};
+    send_response(ctxt->port, output);
+    return;
+  }
+
+  /* Command is in the buffer's first byte */
+  switch(cmd) {
+
+  case OPEN: {
+    char *name = driver_alloc(ev->size - 1+1);
+    struct OS_redir_entry redir[2];
+
+    redir[0].sig = 1;
+    redir[0].pid = current_process();
+
+    iov_memcpy(name,ev,q,p);
+    name[ev->size-1] = '\0';
+
+    ctxt->spid = create_process(OS_PHANTOM, name, NULL, 0,
+				0, 0, 0, redir, 0, 0);
+
+    DEBUGP("0x%x: open\n",ctxt->spid);
+
+    ctxt->perm_events[1] =
+      erl_drv_ose_event_alloc(ERTS_SIGNAL_OSE_DRV_ATTACH,(int)ctxt->spid);
+    driver_select(ctxt->port,ctxt->perm_events[1],ERL_DRV_READ|ERL_DRV_USE,1);
+
+    ctxt->perm_events[0] =
+      erl_drv_ose_event_alloc(ERTS_SIGNAL_OSE_DRV_HUNT,(int)ctxt->spid);
+    driver_select(ctxt->port,ctxt->perm_events[0],ERL_DRV_READ|ERL_DRV_USE,1);
+
+    start(ctxt->spid);
+
+    {
+      ErlDrvTermData output[] = {
+	ERL_DRV_ATOM, a_ose_drv_reply,
+	ERL_DRV_PORT, driver_mk_port(ctxt->port),
+	ERL_DRV_ATOM, a_ok,
+	ERL_DRV_TUPLE, 3};
+
+      send_response(ctxt->port, output);
+    }
+
+    break;
+
+  }
+
+  case ATTACH:
+  case HUNT:
+    {
+      union SIGNAL *sig = alloc(sizeof(union SIGNAL),
+				cmd == HUNT ? ERTS_SIGNAL_OSE_DRV_HUNT:ERTS_SIGNAL_OSE_DRV_ATTACH);
+
+      sig->async.port = driver_mk_port(ctxt->port);
+      sig->async.proc = driver_caller(ctxt->port);
+      sig->async.spid = ctxt->spid;
+      sig->async.ref = ++ctxt->ref;
+
+      if (add_reference(ctxt,ctxt->ref)) {
+	ErlDrvTermData output[] = {
+	  ERL_DRV_ATOM, a_ose_drv_reply,
+	  ERL_DRV_PORT, driver_mk_port(ctxt->port),
+	  ERL_DRV_ATOM, a_enomem,
+	  ERL_DRV_TUPLE, 3};
+	send_response(ctxt->port, output);
+	free_buf(&sig);
+      } else {
+	ErlDrvTermData output[] = {
+	  ERL_DRV_ATOM, a_ose_drv_reply,
+	  ERL_DRV_PORT, driver_mk_port(ctxt->port),
+	  ERL_DRV_PORT, driver_mk_port(ctxt->port),
+	  ERL_DRV_INT, (ErlDrvUInt)ctxt->ref,
+	  ERL_DRV_TUPLE, 2,
+	  ERL_DRV_TUPLE, 3};
+	send_response(ctxt->port, output);
+
+	if (cmd == HUNT) {
+	  char *huntname = driver_alloc(sizeof(char)*((ev->size-1)+1));
+
+	  iov_memcpy(huntname,ev,q,p);
+	  huntname[ev->size-1] = '\0';
+
+	  DEBUGP_HUNT("0x%x: hunt %s -> %u (%u,%u)\n",
+		      ctxt->spid,huntname,ctxt->ref,
+		      ctxt->outstanding_refs_cnt,
+		      ctxt->outstanding_refs_max);
+
+	  hunt(huntname, 0, NULL, &sig);
+
+	  driver_free(huntname);
+	} else {
+	  EV_GET_UINT32(ev,&sig->async.target,&p,&q);
+	  DEBUGP_ATTACH("0x%x: attach %u -> %u (%u,%u)\n",
+			ctxt->spid,sig->async.target,
+			ctxt->ref,
+			ctxt->outstanding_refs_cnt,
+			ctxt->outstanding_refs_max);
+
+	  send(&sig,proxy_proc);
+	}
+
+      }
+
+      break;
+    }
+
+  case DETACH:
+  case DEHUNT:
+    {
+
+        Uint32 ref;
+
+	EV_GET_UINT32(ev,&ref,&p,&q);
+	if (cmd == DETACH) {
+	  DEBUGP_ATTACH("0x%x: detach %u (%u,%u)\n",ctxt->spid,ref,
+			ctxt->outstanding_refs_cnt,
+			ctxt->outstanding_refs_max);
+	} else {
+	  DEBUGP_HUNT("0x%x: dehunt %u (%u,%u)\n",ctxt->spid,ref,
+		      ctxt->outstanding_refs_cnt,
+		      ctxt->outstanding_refs_max);
+	}
+
+	if (remove_reference(ctxt,ref)) {
+	  ErlDrvTermData output[] = {
+	    ERL_DRV_ATOM, a_ose_drv_reply,
+	    ERL_DRV_PORT, driver_mk_port(ctxt->port),
+	    ERL_DRV_ATOM, a_error,
+	    ERL_DRV_ATOM, a_enoent,
+	    ERL_DRV_TUPLE, 2,
+	    ERL_DRV_TUPLE, 3};
+
+	  send_response(ctxt->port, output);
+	} else {
+	  ErlDrvTermData output[] = {
+	    ERL_DRV_ATOM, a_ose_drv_reply,
+	    ERL_DRV_PORT, driver_mk_port(ctxt->port),
+	    ERL_DRV_ATOM, a_ok,
+	    ERL_DRV_TUPLE, 3};
+
+	  send_response(ctxt->port, output);
+	}
+
+      break;
+    }
+
+  case SEND:
+  case SEND_W_S:
+    {
+      PROCESS spid;
+      PROCESS sender;
+      SIGSELECT signo;
+      OSBUFSIZE size = ev->size-9;
+      union SIGNAL *sig;
+
+      EV_GET_UINT32(ev,&spid,&p,&q);
+
+      if (cmd == SEND_W_S) {
+	EV_GET_UINT32(ev,&sender,&p,&q);
+	size -= 4;
+      } else {
+	sender = ctxt->spid;
+      }
+
+      EV_GET_UINT32(ev,&signo,&p,&q);
+
+      sig = alloc(size + sizeof(SIGSELECT),signo);
+
+      if (cmd == SEND_W_S) {
+	DEBUGP_SEND("0x%x: send_w_s(%u,%u,%u)\n",ctxt->spid,spid,signo,sender);
+      } else {
+	DEBUGP_SEND("0x%x: send(%u,%u)\n",ctxt->spid,spid,signo);
+      }
+
+      iov_memcpy(((char *)&sig->signo) + sizeof(SIGSELECT),ev,q,p);
+
+      send_w_s(&sig, sender, spid);
+
+      break;
+    }
+
+    case LISTEN:
+    {
+      int i,j,event_cnt = (ev->size - 1)/4;
+      ErlDrvEvent *events = NULL;
+      SIGSELECT signo,tmp_signo;
+
+      if (event_cnt == 0) {
+	for (i = 0; i < ctxt->event_cnt; i++)
+	  driver_select(ctxt->port,ctxt->events[i],ERL_DRV_READ|ERL_DRV_USE,0);
+	if (ctxt->events)
+	  driver_free(ctxt->events);
+      } else {
+	events = driver_alloc(sizeof(ErlDrvEvent)*event_cnt);
+	EV_GET_UINT32(ev,&signo,&p,&q);
+	for (i = 0, j = 0; i < event_cnt || j < ctxt->event_cnt; ) {
+
+	  if (ctxt->events)
+	    erl_drv_ose_event_fetch(ctxt->events[j],&tmp_signo,NULL);
+
+	  if (signo == tmp_signo) {
+	    events[i++] = ctxt->events[j++];
+	    EV_GET_UINT32(ev,&signo,&p,&q);
+	  } else if (signo < tmp_signo || !ctxt->events) {
+	    /* New signal to select on */
+	    events[i] = erl_drv_ose_event_alloc(signo,(int)ctxt->spid);
+	    driver_select(ctxt->port,events[i++],ERL_DRV_READ|ERL_DRV_USE,1);
+	    EV_GET_UINT32(ev,&signo,&p,&q);
+	  } else {
+	    /* Remove old signal to select on */
+	    driver_select(ctxt->port,ctxt->events[j++],ERL_DRV_READ|ERL_DRV_USE,0);
+	  }
+	}
+	if (ctxt->events)
+	  driver_free(ctxt->events);
+      }
+      ctxt->events = events;
+      ctxt->event_cnt = event_cnt;
+
+      {
+	ErlDrvTermData output[] = {
+	  ERL_DRV_ATOM, a_ose_drv_reply,
+	  ERL_DRV_PORT, driver_mk_port(ctxt->port),
+	  ERL_DRV_ATOM, a_ok,
+	  ERL_DRV_TUPLE, 3};
+	send_response(ctxt->port, output);
+      }
+      break;
+    }
+
+    default:
+    {
+      DEBUGP("Warning: 'ose_signal_drv' unknown command '%d'\n", cmd);
+      break;
+    }
+  }
+}
+
+/**
+ * Handler for when OSE signal arrives
+ **/
+static void ready_input(ErlDrvData driver_data, ErlDrvEvent event)
+{
+  driver_context_t *ctxt = (driver_context_t *)driver_data;
+  union SIGNAL *sig = erl_drv_ose_get_input_signal(event);
+
+  while (sig != NULL) {
+
+    switch(sig->signo)
+      {
+	/* Remote process is available */
+      case ERTS_SIGNAL_OSE_DRV_HUNT:
+	{
+	  const PROCESS spid = sender(&sig);
+
+	  if (remove_reference(ctxt,sig->async.ref)) {
+	    DEBUGP_HUNT("0x%x: Got hunt from 0x%x -> %u (CANCELLED) (%u,%u)\n",
+			ctxt->spid,spid,sig->async.ref,
+			ctxt->outstanding_refs_cnt,
+			ctxt->outstanding_refs_max);
+	    /* Already removed by dehunt */
+	  } else {
+	    ErlDrvTermData reply[] = {
+	      ERL_DRV_ATOM, a_mailbox_up,
+	      ERL_DRV_PORT, sig->async.port,
+	      ERL_DRV_PORT, sig->async.port,
+	      ERL_DRV_UINT, (ErlDrvUInt)sig->async.ref,
+	      ERL_DRV_TUPLE, 2,
+	      ERL_DRV_UINT, (ErlDrvUInt)spid,
+	      ERL_DRV_TUPLE, 4};
+	    DEBUGP_HUNT("0x%x: Got hunt from 0x%x -> %u (%u,%u)\n",
+			ctxt->spid,spid,sig->async.ref,
+			ctxt->outstanding_refs_cnt,
+			ctxt->outstanding_refs_max);
+	    erl_drv_send_term(sig->async.port, sig->async.proc, reply,
+			      sizeof(reply) / sizeof(reply[0]));
+	  }
+	  break;
+	}
+
+	/* Remote process is down */
+      case ERTS_SIGNAL_OSE_DRV_ATTACH:
+	{
+	  PROCESS spid = sig->async.target;
+
+	  if (remove_reference(ctxt,sig->async.ref)) {
+	    DEBUGP_ATTACH("0x%x: Got attach from 0x%x -> %u (CANCELLED) (%u,%u)\n",
+			  ctxt->spid,spid,sig->async.ref,
+			  ctxt->outstanding_refs_cnt,
+			  ctxt->outstanding_refs_max);
+	    /* Already removed by detach */
+	  } else {
+	    ErlDrvTermData reply[] = {
+	      ERL_DRV_ATOM, a_mailbox_down,
+	      ERL_DRV_PORT, sig->async.port,
+	      ERL_DRV_PORT, sig->async.port,
+	      ERL_DRV_UINT, sig->async.ref,
+	      ERL_DRV_TUPLE, 2,
+	      ERL_DRV_UINT, (ErlDrvUInt)spid,
+	      ERL_DRV_TUPLE, 4};
+	     DEBUGP_ATTACH("0x%x: Got attach from 0x%x -> %u (%u,%u)\n",
+			   ctxt->spid,spid,sig->async.ref,
+			   ctxt->outstanding_refs_cnt,
+			   ctxt->outstanding_refs_max);
+	    erl_drv_send_term(sig->async.port, sig->async.proc, reply,
+			      sizeof(reply) / sizeof(reply[0]));
+	  }
+	  break;
+	}
+
+	/* Received user defined signal */
+      default:
+	{
+	  const PROCESS spid = sender(&sig);
+	  const OSBUFSIZE size = sigsize(&sig) - sizeof(SIGSELECT);
+	  const char *sig_data = ((char *)&sig->signo) + sizeof(SIGSELECT);
+
+	  ErlDrvTermData reply[] = {
+	    ERL_DRV_ATOM, a_message,
+	    ERL_DRV_PORT, driver_mk_port(ctxt->port),
+	    ERL_DRV_UINT, (ErlDrvUInt)spid,
+	    ERL_DRV_UINT, (ErlDrvUInt)ctxt->spid,
+	    ERL_DRV_UINT, (ErlDrvUInt)sig->signo,
+	    ERL_DRV_BUF2BINARY, (ErlDrvTermData)sig_data, (ErlDrvUInt)size,
+	    ERL_DRV_TUPLE, 4,
+	    ERL_DRV_TUPLE, 3};
+
+	  DEBUGP_SEND("0x%x: Got 0x%u\r\n", spid, sig->signo);
+
+	  erl_drv_output_term(driver_mk_port(ctxt->port), reply,
+			      sizeof(reply) / sizeof(reply[0]));
+	  break;
+	}
+      }
+
+    free_buf(&sig);
+    sig = erl_drv_ose_get_input_signal(event);
+  }
+}
+
+/**
+ * Handler for 'port_control'
+ **/
+static ErlDrvSSizeT control(ErlDrvData driver_data, unsigned int cmd,
+                            char *buf, ErlDrvSizeT len,
+                            char **rbuf, ErlDrvSizeT rlen)
+{
+  driver_context_t *ctxt = (driver_context_t *)driver_data;
+
+  switch(cmd)
+  {
+    case GET_SPID:
+    {
+      const PROCESS spid = ctxt->spid;
+      put_u32(spid, *rbuf);
+      return sizeof(PROCESS);
+    }
+
+    case GET_NAME:
+    {
+      const PROCESS spid = get_u32(buf);
+      char *name = (char*)get_pid_info(spid,OSE_PI_NAME);
+      int n;
+      if (!name) {
+	*rbuf = NULL;
+	return 0;
+      }
+
+      if (rlen < (n = strlen(name))) {
+	ErlDrvBinary *bin = driver_alloc_binary(n);
+	strncpy(bin->orig_bytes,name,n);
+	*rbuf = (char*)bin;
+      } else
+	strncpy(*rbuf,name,n);
+      free_buf((union SIGNAL**)&name);
+
+      return n;
+    }
+    default:
+    {
+      /* Unknown command */
+      return (ErlDrvSSizeT)ERL_DRV_ERROR_GENERAL;
+      break;
+    }
+  }
+}
+
+static void stop_select(ErlDrvEvent event, void *reserved)
+{
+  erl_drv_ose_event_free(event);
+}
+
+static int resolve_signal(OseSignal* osig, int *mode) {
+  union SIGNAL *sig = osig;
+  if (sig->signo == ERTS_SIGNAL_OSE_DRV_HUNT ||
+      sig->signo == ERTS_SIGNAL_OSE_DRV_ATTACH) {
+    return sig->async.spid;
+  }
+  DEBUGP("%p: Got signal %d sent to %p from 0x%p\n",
+	 current_process(),sig->signo,addressee(&sig),sender(&sig));
+  return addressee(&sig);
+}
+
+/**
+ * Setup the driver entry for the Erlang runtime
+ **/
+ErlDrvEntry ose_signal_driver_entry = {
+  .init                         = drv_init,
+  .start                        = drv_start,
+  .stop                         = drv_stop,
+  .outputv                      = outputv,
+  .ready_input                  = ready_input,
+  .driver_name                  = DRIVER_NAME,
+  .control                      = control,
+  .extended_marker              = ERL_DRV_EXTENDED_MARKER,
+  .major_version                = ERL_DRV_EXTENDED_MAJOR_VERSION,
+  .minor_version                = ERL_DRV_EXTENDED_MINOR_VERSION,
+  .driver_flags                 = ERL_DRV_FLAG_USE_PORT_LOCKING,
+  .stop_select                  = stop_select,
+  .resolve_signal               = resolve_signal
+};