text: /*
   * %CopyrightBegin%
   *
   * Copyright Ericsson AB 1996-2016. All Rights Reserved.
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   *
   * %CopyrightEnd%
   */
  
  /*
   * distribution of erlang messages to other nodes.
   */
  
  
  /* define this to get a lot of debug output */
  /* #define ERTS_DIST_MSG_DBG */
  /* #define ERTS_RAW_DIST_MSG_DBG */
  
  #ifdef HAVE_CONFIG_H
  #  include "config.h"
  #endif
  
  #define ERTS_WANT_EXTERNAL_TAGS
  
  #include <stddef.h>
  #include "sys.h"
  #include "erl_vm.h"
  #include "global.h"
  #include "erl_process.h"
  #include "error.h"
  #include "dist.h"
  #include "bif.h"
  #include "external.h"
  #include "erl_binary.h"
  #include "erl_thr_progress.h"
  #include "dtrace-wrapper.h"
  
  #define DIST_CTL_DEFAULT_SIZE 64
  
  /* Turn this on to get printouts of all distribution messages
   * which go on the line
   */
  #if 0
  #define ERTS_DIST_MSG_DBG
  #endif
  #if 0
  #define ERTS_RAW_DIST_MSG_DBG
  #endif
  
  #if defined(ERTS_DIST_MSG_DBG) || defined(ERTS_RAW_DIST_MSG_DBG)
  static void bw(byte *buf, ErlDrvSizeT sz)
  {
      bin_write(ERTS_PRINT_STDERR, NULL, buf, sz);
  }
  #endif
  
  #ifdef ERTS_DIST_MSG_DBG
  static void
  dist_msg_dbg(ErtsDistExternal *edep, char *what, byte *buf, int sz)
  {
      ErtsHeapFactory factory;
      DeclareTmpHeapNoproc(ctl_default,DIST_CTL_DEFAULT_SIZE);
      Eterm* ctl = ctl_default;
      byte *extp = edep->extp;
      Eterm msg;
      Sint ctl_len;
      Sint size = ctl_len = erts_decode_dist_ext_size(edep);
      if (size < 0) {
  	erts_fprintf(stderr,
  		     "DIST MSG DEBUG: erts_decode_dist_ext_size(%s) failed:\n",
  		     what);
  	bw(buf, sz);
      }
      else {
  	ErlHeapFragment *mbuf = new_message_buffer(size);
  	erts_factory_static_init(&factory, ctl, ctl_len, &mbuf->off_heap);
  	msg = erts_decode_dist_ext(&factory, edep);
  	if (is_value(msg))
  	    erts_fprintf(stderr, "    %s: %T\n", what, msg);
  	else {
  	    erts_fprintf(stderr,
  			 "DIST MSG DEBUG: erts_decode_dist_ext(%s) failed:\n",
  			 what);
  	    bw(buf, sz);
  	}
  	free_message_buffer(mbuf);
  	edep->extp = extp;
      }
  }
  
  #endif
  
  
  
  #define PASS_THROUGH 'p'        /* This code should go */
  
  int erts_is_alive; /* System must be blocked on change */
  int erts_dist_buf_busy_limit;
  
  
  /* distribution trap functions */
  Export* dsend2_trap = NULL;
  Export* dsend3_trap = NULL;
  /*Export* dsend_nosuspend_trap = NULL;*/
  Export* dlink_trap = NULL;
  Export* dunlink_trap = NULL;
  Export* dmonitor_node_trap = NULL;
  Export* dgroup_leader_trap = NULL;
  Export* dexit_trap = NULL;
  Export* dmonitor_p_trap = NULL;
  
  /* local variables */
  
  
  /* forward declarations */
  
  static void clear_dist_entry(DistEntry*);
  static int dsig_send_ctl(ErtsDSigData* dsdp, Eterm ctl, int force_busy);
  static void send_nodes_mon_msgs(Process *, Eterm, Eterm, Eterm, Eterm);
  static void init_nodes_monitors(void);
  
  static erts_smp_atomic_t no_caches;
  static erts_smp_atomic_t no_nodes;
  
  struct {
      Eterm reason;
      ErlHeapFragment *bp;
  } nodedown;
  
  
  static void
  delete_cache(ErtsAtomCache *cache)
  {
      if (cache) {
  	erts_free(ERTS_ALC_T_DCACHE, (void *) cache);
  	ASSERT(erts_smp_atomic_read_nob(&no_caches) > 0);
  	erts_smp_atomic_dec_nob(&no_caches);
      }
  }
  
  
  static void
  create_cache(DistEntry *dep)
  {
      int i;
      ErtsAtomCache *cp;
  
      ERTS_SMP_LC_ASSERT(
  	is_internal_port(dep->cid)
  	&& erts_lc_is_port_locked(erts_port_lookup_raw(dep->cid)));
      ASSERT(!dep->cache);
  
      dep->cache = cp = (ErtsAtomCache*) erts_alloc(ERTS_ALC_T_DCACHE,
  						  sizeof(ErtsAtomCache));
      erts_smp_atomic_inc_nob(&no_caches);
      for (i = 0; i < sizeof(cp->in_arr)/sizeof(cp->in_arr[0]); i++) {
  	cp->in_arr[i] = THE_NON_VALUE;
  	cp->out_arr[i] = THE_NON_VALUE;
      }
  }
  
  Uint erts_dist_cache_size(void)
  {
      return (Uint) erts_smp_atomic_read_mb(&no_caches)*sizeof(ErtsAtomCache);
  }
  
  static ErtsProcList *
  get_suspended_on_de(DistEntry *dep, Uint32 unset_qflgs)
  {
      ERTS_SMP_LC_ASSERT(erts_smp_lc_mtx_is_locked(&dep->qlock));
      dep->qflgs &= ~unset_qflgs;
      if (dep->qflgs & ERTS_DE_QFLG_EXIT) {
  	/* No resume when exit has been scheduled */
  	return NULL;
      }
      else {
  	ErtsProcList *suspended = dep->suspended;
  	dep->suspended = NULL;
  	erts_proclist_fetch(&suspended, NULL);
  	return suspended;
      }
  }
  
  /*
  ** A full node name constists of a "n@h"
  **
  ** n must be a valid node name: string of ([a-z][A-Z][0-9]_-)+
  ** 
  ** h is not checked at all, we assume that we have a properly
  ** configured machine where the networking is ok for the OS
  **
  ** We do check that there is not a second @ in the string, since
  ** many distributed operations are guaranteed not to work then.
  */
  
  
  static int is_node_name(char *ptr, int len)
  {
     int c = '\0';		/* suppress use-before-set warning */
     int pos = 0;
  
     while (pos < len) {
        c = ptr[pos++];
        if (! ((c == '-') || (c == '_') ||
  	     ((c >= 'a') && (c <= 'z')) ||
  	     ((c >= 'A') && (c <= 'Z')) ||
  	     ((c >= '0') && (c <= '9'))))
  	 break;
     }
  
     /* Scanned past the host name: now we want to see a '@', and there
        should be text both before and after it. */
     if (c != '@' || pos < 2 || pos == len)
        return 0;
  
     while (pos < len) {
        c = ptr[pos++];
        if (c == '@')
  	 return 0;
     }
  
     return 1;
  }
  
  int is_node_name_atom(Eterm a)
  {
      int i;
      if(is_not_atom(a))
  	return 0;
      i = atom_val(a);
      ASSERT((i > 0) && (i < atom_table_size()) &&  (atom_tab(i) != NULL));
      return is_node_name((char*)atom_tab(i)->name, atom_tab(i)->len);
  }
  
  typedef struct {
      DistEntry *dep;
      Eterm *lhp;
  } NetExitsContext;
  
  /* 
  ** This function is called when a distribution 
  ** port or process terminates
  */
  static void doit_monitor_net_exits(ErtsMonitor *mon, void *vnecp)
  {
      Process *rp;
      ErtsMonitor *rmon;
      DistEntry *dep = ((NetExitsContext *) vnecp)->dep;
      ErtsProcLocks rp_locks = ERTS_PROC_LOCK_LINK;
  
      rp = erts_pid2proc(NULL, 0, mon->u.pid, rp_locks);
      if (!rp)
  	goto done;
  
      if (mon->type == MON_ORIGIN) {
  	/* local pid is being monitored */
  	rmon = erts_remove_monitor(&ERTS_P_MONITORS(rp), mon->ref);
  	/* ASSERT(rmon != NULL); nope, can happen during process exit */
  	if (rmon != NULL) {
  	    erts_destroy_monitor(rmon);
  	}
      } else {
  	DeclareTmpHeapNoproc(lhp,3);
  	Eterm watched;
  	UseTmpHeapNoproc(3);
  	ASSERT(mon->type == MON_TARGET);
  	rmon = erts_remove_monitor(&ERTS_P_MONITORS(rp), mon->ref);
  	/* ASSERT(rmon != NULL); can happen during process exit */
  	if (rmon != NULL) {
              ASSERT(rmon->type == MON_ORIGIN);
  	    ASSERT(is_atom(rmon->name) || is_nil(rmon->name));
  	    watched = (is_atom(rmon->name)
  		       ? TUPLE2(lhp, rmon->name, dep->sysname)
  		       : rmon->u.pid);
  #ifdef ERTS_SMP
  	    rp_locks |= ERTS_PROC_LOCKS_MSG_SEND;
  	    erts_smp_proc_lock(rp, ERTS_PROC_LOCKS_MSG_SEND);
  #endif
  	    erts_queue_monitor_message(rp, &rp_locks, mon->ref, am_process, 
  				       watched, am_noconnection);
  	    erts_destroy_monitor(rmon);
  	}
  	UnUseTmpHeapNoproc(3);
      }
      erts_smp_proc_unlock(rp, rp_locks);
   done:
      erts_destroy_monitor(mon);
  }
  	
  typedef struct {
      NetExitsContext *necp;
      ErtsLink *lnk;
  } LinkNetExitsContext;
  
  /* 
  ** This is the function actually doing the job of sending exit messages
  ** for links in a dist entry upon net_exit (the node goes down), NB,
  ** only process links, not node monitors are handled here, 
  ** they reside in a separate tree....
  */
  static void doit_link_net_exits_sub(ErtsLink *sublnk, void *vlnecp)
  {
      ErtsLink *lnk = ((LinkNetExitsContext *) vlnecp)->lnk; /* the local pid */
      ErtsLink *rlnk;
      Process *rp;
  
      ASSERT(lnk->type == LINK_PID);
      if (is_internal_pid(lnk->pid)) {
  	int xres;
  	ErtsProcLocks rp_locks = ERTS_PROC_LOCK_LINK|ERTS_PROC_LOCKS_XSIG_SEND;
  
  	rp = erts_pid2proc(NULL, 0, lnk->pid, rp_locks);
  	if (!rp) {
  	    goto done;
  	}
  
  	rlnk = erts_remove_link(&ERTS_P_LINKS(rp), sublnk->pid);
  	xres = erts_send_exit_signal(NULL,
  				     sublnk->pid,
  				     rp,
  				     &rp_locks,
  				     am_noconnection,
  				     NIL,
  				     NULL,
  				     0);
  
  	if (rlnk) {
  	    erts_destroy_link(rlnk);
  	    if (xres >= 0 && IS_TRACED_FL(rp, F_TRACE_PROCS)) {
  		/* We didn't exit the process and it is traced */
  		trace_proc(NULL, 0, rp, am_getting_unlinked, sublnk->pid);
  	    }
  	}
  	erts_smp_proc_unlock(rp, rp_locks);
      }
   done:
      erts_destroy_link(sublnk);
  
  }
      
  
  
  
  
  /* 
  ** This function is called when a distribution 
  ** port or process terminates, once for each link on the high level, 
  ** it in turn traverses the link subtree for the specific link node...
  */
  static void doit_link_net_exits(ErtsLink *lnk, void *vnecp)
  {
      LinkNetExitsContext lnec = {(NetExitsContext *) vnecp, lnk};
      ASSERT(lnk->type == LINK_PID);
      erts_sweep_links(ERTS_LINK_ROOT(lnk), &doit_link_net_exits_sub, (void *) &lnec);
  #ifdef DEBUG
      ERTS_LINK_ROOT(lnk) = NULL;
  #endif
      erts_destroy_link(lnk);
  }
  
  
  static void doit_node_link_net_exits(ErtsLink *lnk, void *vnecp)
  {
      DistEntry *dep = ((NetExitsContext *) vnecp)->dep;
      Eterm name = dep->sysname;
      Process *rp;
      ErtsLink *rlnk;
      Uint i,n;
      ASSERT(lnk->type == LINK_NODE);
      if (is_internal_pid(lnk->pid)) {
  	ErtsProcLocks rp_locks = ERTS_PROC_LOCK_LINK;
  	ErlOffHeap *ohp;
  	rp = erts_proc_lookup(lnk->pid);
  	if (!rp)
  	    goto done;
  	erts_smp_proc_lock(rp, rp_locks);
  	rlnk = erts_remove_link(&ERTS_P_LINKS(rp), name);
  	if (rlnk != NULL) {
  	    ASSERT(is_atom(rlnk->pid) && (rlnk->type == LINK_NODE));
  	    erts_destroy_link(rlnk);
  	}
  	n = ERTS_LINK_REFC(lnk);
  	for (i = 0; i < n; ++i) {
  	    Eterm tup;
  	    Eterm *hp;
  	    ErtsMessage *msgp;
  
  	    msgp = erts_alloc_message_heap(rp, &rp_locks,
  					   3, &hp, &ohp);
  	    tup = TUPLE2(hp, am_nodedown, name);
  	    erts_queue_message(rp, rp_locks, msgp, tup, am_system);
  	}
  	erts_smp_proc_unlock(rp, rp_locks);
      }
   done:
      erts_destroy_link(lnk);
  }
  
  static void
  set_node_not_alive(void *unused)
  {
      ErlHeapFragment *bp;
      Eterm nodename = erts_this_dist_entry->sysname;
  
      ASSERT(erts_smp_atomic_read_nob(&no_nodes) == 0);
  
      erts_smp_thr_progress_block();
      erts_set_this_node(am_Noname, 0);
      erts_is_alive = 0;
      send_nodes_mon_msgs(NULL, am_nodedown, nodename, am_visible, nodedown.reason);
      nodedown.reason = NIL;
      bp = nodedown.bp;
      nodedown.bp = NULL;
      erts_smp_thr_progress_unblock();
      if (bp)
  	free_message_buffer(bp);
  }
  
  static ERTS_INLINE void
  dec_no_nodes(void)
  {
      erts_aint_t no = erts_smp_atomic_dec_read_mb(&no_nodes);
      ASSERT(no >= 0);
      ASSERT(erts_get_scheduler_id()); /* Need to be a scheduler */
      if (no == 0)
  	erts_schedule_misc_aux_work(erts_get_scheduler_id(),
  				    set_node_not_alive,
  				    NULL);
  }
  
  static ERTS_INLINE void
  inc_no_nodes(void)
  {
  #ifdef DEBUG
      erts_aint_t no = erts_smp_atomic_read_nob(&no_nodes);
      ASSERT(erts_is_alive ? no > 0 : no == 0);
  #endif
      erts_smp_atomic_inc_mb(&no_nodes);
  }
  	
  /*
   * proc is currently running or exiting process.
   */
  int erts_do_net_exits(DistEntry *dep, Eterm reason)
  {
      Eterm nodename;
  
      if (dep == erts_this_dist_entry) {  /* Net kernel has died (clean up!!) */
  	DistEntry *tdep;
  	int no_dist_port = 0;
  	Eterm nd_reason = (reason == am_no_network
  			   ? am_no_network
  			   : am_net_kernel_terminated);
  	erts_smp_rwmtx_rlock(&erts_dist_table_rwmtx);
  
  	for (tdep = erts_hidden_dist_entries; tdep; tdep = tdep->next)
  	    no_dist_port++;
  	for (tdep = erts_visible_dist_entries; tdep; tdep = tdep->next)
  	    no_dist_port++;
  
  	/* KILL all port controllers */
  	if (no_dist_port == 0)
  	    erts_smp_rwmtx_runlock(&erts_dist_table_rwmtx);
  	else {
  	    Eterm def_buf[128];
  	    int i = 0;
  	    Eterm *dist_port;
  
  	    if (no_dist_port <= sizeof(def_buf)/sizeof(def_buf[0]))
  		dist_port = &def_buf[0];
  	    else
  		dist_port = erts_alloc(ERTS_ALC_T_TMP,
  				       sizeof(Eterm)*no_dist_port);
  	    for (tdep = erts_hidden_dist_entries; tdep; tdep = tdep->next) {
  		ASSERT(is_internal_port(tdep->cid));
  		dist_port[i++] = tdep->cid;
  	    }
  	    for (tdep = erts_visible_dist_entries; tdep; tdep = tdep->next) {
  		ASSERT(is_internal_port(tdep->cid));
  		dist_port[i++] = tdep->cid;
  	    }
  	    erts_smp_rwmtx_runlock(&erts_dist_table_rwmtx);
  
  	    for (i = 0; i < no_dist_port; i++) {
  		Port *prt = erts_port_lookup(dist_port[i],
  					     ERTS_PORT_SFLGS_INVALID_LOOKUP);
  		if (!prt)
  		    continue;
  		ASSERT(erts_atomic32_read_nob(&prt->state)
  		       & ERTS_PORT_SFLG_DISTRIBUTION);
  
  		erts_port_exit(NULL, ERTS_PORT_SIG_FLG_FORCE_SCHED,
  			       prt, dist_port[i], nd_reason, NULL);
  	    }
  
  	    if (dist_port != &def_buf[0])
  		erts_free(ERTS_ALC_T_TMP, dist_port);
  	}
  
  	/*
  	 * When last dist port exits, node will be taken
  	 * from alive to not alive.
  	 */
  	ASSERT(is_nil(nodedown.reason) && !nodedown.bp);
  	if (is_immed(nd_reason))
  	    nodedown.reason = nd_reason;
  	else {
  	    Eterm *hp;
  	    Uint sz = size_object(nd_reason);
  	    nodedown.bp = new_message_buffer(sz);
  	    hp = nodedown.bp->mem;
  	    nodedown.reason = copy_struct(nd_reason,
  					  sz,
  					  &hp,
  					  &nodedown.bp->off_heap);
  	}
      }
      else { /* Call from distribution port */
  	NetExitsContext nec = {dep};
  	ErtsLink *nlinks;
  	ErtsLink *node_links;
  	ErtsMonitor *monitors;
  	Uint32 flags;
  
  	erts_smp_atomic_set_mb(&dep->dist_cmd_scheduled, 1);
  	erts_smp_de_rwlock(dep);
  
  	ERTS_SMP_LC_ASSERT(is_internal_port(dep->cid)
  			   && erts_lc_is_port_locked(erts_port_lookup_raw(dep->cid)));
  
  	if (erts_port_task_is_scheduled(&dep->dist_cmd))
  	    erts_port_task_abort(&dep->dist_cmd);
  
  	if (dep->status & ERTS_DE_SFLG_EXITING) {
  #ifdef DEBUG
  	    erts_smp_mtx_lock(&dep->qlock);
  	    ASSERT(dep->qflgs & ERTS_DE_QFLG_EXIT);
  	    erts_smp_mtx_unlock(&dep->qlock);
  #endif
  	}
  	else {
  	    dep->status |= ERTS_DE_SFLG_EXITING;
  	    erts_smp_mtx_lock(&dep->qlock);
  	    ASSERT(!(dep->qflgs & ERTS_DE_QFLG_EXIT));
  	    dep->qflgs |= ERTS_DE_QFLG_EXIT;
  	    erts_smp_mtx_unlock(&dep->qlock);
  	}
  
  	erts_smp_de_links_lock(dep);
  	monitors	= dep->monitors;
          nlinks		= dep->nlinks;
  	node_links	= dep->node_links;
  	dep->monitors	= NULL;
          dep->nlinks	= NULL;
  	dep->node_links	= NULL;
  	erts_smp_de_links_unlock(dep);
  
  	nodename = dep->sysname;
  	flags = dep->flags;
  
  	erts_set_dist_entry_not_connected(dep);
  
  	erts_smp_de_rwunlock(dep);
  
  	erts_sweep_monitors(monitors, &doit_monitor_net_exits, (void *) &nec);
  	erts_sweep_links(nlinks, &doit_link_net_exits, (void *) &nec);
  	erts_sweep_links(node_links, &doit_node_link_net_exits, (void *) &nec);
  
  	send_nodes_mon_msgs(NULL,
  			    am_nodedown,
  			    nodename,
  			    flags & DFLAG_PUBLISHED ? am_visible : am_hidden,
  			    reason == am_normal ? am_connection_closed : reason);
  
  	clear_dist_entry(dep);
  
      }
  
      dec_no_nodes();
  
      return 1;
  }
  
  static Export*
  trap_function(Eterm func, int arity)
  {
      return erts_export_put(am_erlang, func, arity);
  }
  
  void init_dist(void)
  {
      init_nodes_monitors();
  
      nodedown.reason = NIL;
      nodedown.bp = NULL;
  
      erts_smp_atomic_init_nob(&no_nodes, 0);
      erts_smp_atomic_init_nob(&no_caches, 0);
  
      /* Lookup/Install all references to trap functions */
      dsend2_trap = trap_function(am_dsend,2);
      dsend3_trap = trap_function(am_dsend,3);
      /*    dsend_nosuspend_trap = trap_function(am_dsend_nosuspend,2);*/
      dlink_trap = trap_function(am_dlink,1);
      dunlink_trap = trap_function(am_dunlink,1);
      dmonitor_node_trap = trap_function(am_dmonitor_node,3);
      dgroup_leader_trap = trap_function(am_dgroup_leader,2);
      dexit_trap = trap_function(am_dexit, 2);
      dmonitor_p_trap = trap_function(am_dmonitor_p, 2);
  }
  
  #define ErtsDistOutputBuf2Binary(OB) \
    ((Binary *) (((char *) (OB)) - offsetof(Binary, orig_bytes)))
  
  static ERTS_INLINE ErtsDistOutputBuf *
  alloc_dist_obuf(Uint size)
  {
      ErtsDistOutputBuf *obuf;
      Uint obuf_size = sizeof(ErtsDistOutputBuf)+sizeof(byte)*(size-1);
      Binary *bin = erts_bin_drv_alloc(obuf_size);
      erts_refc_init(&bin->refc, 1);
      obuf = (ErtsDistOutputBuf *) &bin->orig_bytes[0];
  #ifdef DEBUG
      obuf->dbg_pattern = ERTS_DIST_OUTPUT_BUF_DBG_PATTERN;
      ASSERT(bin == ErtsDistOutputBuf2Binary(obuf));
  #endif
      return obuf;
  }
  
  static ERTS_INLINE void
  free_dist_obuf(ErtsDistOutputBuf *obuf)
  {
      Binary *bin = ErtsDistOutputBuf2Binary(obuf);
      ASSERT(obuf->dbg_pattern == ERTS_DIST_OUTPUT_BUF_DBG_PATTERN);
      if (erts_refc_dectest(&bin->refc, 0) == 0)
  	erts_bin_free(bin);
  }
  
  static ERTS_INLINE Sint
  size_obuf(ErtsDistOutputBuf *obuf)
  {
      Binary *bin = ErtsDistOutputBuf2Binary(obuf);
      return bin->orig_size;
  }
  
  static void clear_dist_entry(DistEntry *dep)
  {
      Sint obufsize = 0;
      ErtsAtomCache *cache;
      ErtsProcList *suspendees;
      ErtsDistOutputBuf *obuf;
  
      erts_smp_de_rwlock(dep);
      cache = dep->cache;
      dep->cache = NULL;
  
  #ifdef DEBUG
      erts_smp_de_links_lock(dep);
      ASSERT(!dep->nlinks);
      ASSERT(!dep->node_links);
      ASSERT(!dep->monitors);
      erts_smp_de_links_unlock(dep);
  #endif
  
      erts_smp_mtx_lock(&dep->qlock);
  
      if (!dep->out_queue.last)
  	obuf = dep->finalized_out_queue.first;
      else {
  	dep->out_queue.last->next = dep->finalized_out_queue.first;
  	obuf = dep->out_queue.first;
      }
  
      dep->out_queue.first = NULL;
      dep->out_queue.last = NULL;
      dep->finalized_out_queue.first = NULL;
      dep->finalized_out_queue.last = NULL;
      dep->status = 0;
      suspendees = get_suspended_on_de(dep, ERTS_DE_QFLGS_ALL);
  
      erts_smp_mtx_unlock(&dep->qlock);
      erts_smp_atomic_set_nob(&dep->dist_cmd_scheduled, 0);
      dep->send = NULL;
      erts_smp_de_rwunlock(dep);
  
      erts_resume_processes(suspendees);
  
      delete_cache(cache);
  
      while (obuf) {
  	ErtsDistOutputBuf *fobuf;
  	fobuf = obuf;
  	obuf = obuf->next;
  	obufsize += size_obuf(fobuf);
  	free_dist_obuf(fobuf);
      }
  
      if (obufsize) {
  	erts_smp_mtx_lock(&dep->qlock);
  	ASSERT(dep->qsize >= obufsize);
  	dep->qsize -= obufsize;
  	erts_smp_mtx_unlock(&dep->qlock);
      }
  }
  
  int erts_dsend_context_dtor(Binary* ctx_bin)
  {
      ErtsSendContext* ctx = ERTS_MAGIC_BIN_DATA(ctx_bin);
      switch (ctx->dss.phase) {
      case ERTS_DSIG_SEND_PHASE_MSG_SIZE:
  	DESTROY_SAVED_WSTACK(&ctx->dss.u.sc.wstack);
  	break;
      case ERTS_DSIG_SEND_PHASE_MSG_ENCODE:
  	DESTROY_SAVED_WSTACK(&ctx->dss.u.ec.wstack);
  	break;
      default:;
      }
      if (ctx->dss.phase >= ERTS_DSIG_SEND_PHASE_ALLOC && ctx->dss.obuf) {
  	free_dist_obuf(ctx->dss.obuf);
      }
      if (ctx->dep_to_deref)
  	erts_deref_dist_entry(ctx->dep_to_deref);
  
      return 1;
  }
  
  Eterm erts_dsend_export_trap_context(Process* p, ErtsSendContext* ctx)
  {
      struct exported_ctx {
  	ErtsSendContext ctx;
  	ErtsAtomCacheMap acm;
      };
      Binary* ctx_bin = erts_create_magic_binary(sizeof(struct exported_ctx),
  					       erts_dsend_context_dtor);
      struct exported_ctx* dst = ERTS_MAGIC_BIN_DATA(ctx_bin);
      Eterm* hp = HAlloc(p, ERTS_MAGIC_REF_THING_SIZE);
  
      sys_memcpy(&dst->ctx, ctx, sizeof(ErtsSendContext));
      ASSERT(ctx->dss.ctl == make_tuple(ctx->ctl_heap));
      dst->ctx.dss.ctl = make_tuple(dst->ctx.ctl_heap);
      if (ctx->dss.acmp) {
  	sys_memcpy(&dst->acm, ctx->dss.acmp, sizeof(ErtsAtomCacheMap));
  	dst->ctx.dss.acmp = &dst->acm;
      }
      return erts_mk_magic_ref(&hp, &MSO(p), ctx_bin);
  }
  
  
  /*
   * The erts_dsig_send_*() functions implemented below, sends asynchronous
   * distributed signals to other Erlang nodes. Before sending a distributed
   * signal, you need to prepare the operation by calling erts_dsig_prepare()
   * (see dist.h).
   *
   * Note that the distributed signal send operation is truly asynchronous,
   * and the signal is not guaranteed to reach the receiver if the connection
   * goes down before the signal has reached the receiver.
   */
  
  /*
  ** Send a DOP_LINK link message
  */
  int
  erts_dsig_send_link(ErtsDSigData *dsdp, Eterm local, Eterm remote)
  {
      DeclareTmpHeapNoproc(ctl_heap,4);
      Eterm ctl = TUPLE3(&ctl_heap[0], make_small(DOP_LINK), local, remote);
      int res;
      UseTmpHeapNoproc(4);
  
      res = dsig_send_ctl(dsdp, ctl, 0);
      UnUseTmpHeapNoproc(4);
      return res;
  }
  
  int
  erts_dsig_send_unlink(ErtsDSigData *dsdp, Eterm local, Eterm remote)
  {
      DeclareTmpHeapNoproc(ctl_heap,4);
      Eterm ctl = TUPLE3(&ctl_heap[0], make_small(DOP_UNLINK), local, remote);
      int res;
  
      UseTmpHeapNoproc(4);
      res = dsig_send_ctl(dsdp, ctl, 0);
      UnUseTmpHeapNoproc(4);
      return res;
  }
  
  
  /* A local process that's being monitored by a remote one exits. We send:
     {DOP_MONITOR_P_EXIT, Local pid or name, Remote pid, ref, reason},
     which is rather sad as only the ref is needed, no pid's... */
  int
  erts_dsig_send_m_exit(ErtsDSigData *dsdp, Eterm watcher, Eterm watched, 
  			  Eterm ref, Eterm reason)
  {
      Eterm ctl;
      DeclareTmpHeapNoproc(ctl_heap,6);
      int res;
  
      UseTmpHeapNoproc(6);
  
      ctl = TUPLE5(&ctl_heap[0], make_small(DOP_MONITOR_P_EXIT),
  		 watched, watcher, ref, reason);
  
  #ifdef DEBUG
      erts_smp_de_links_lock(dsdp->dep);
      ASSERT(!erts_lookup_monitor(dsdp->dep->monitors, ref));
      erts_smp_de_links_unlock(dsdp->dep);
  #endif
  
      res = dsig_send_ctl(dsdp, ctl, 1);
      UnUseTmpHeapNoproc(6);
      return res;
  }
  
  /* We want to monitor a process (named or unnamed) on another node, we send:
     {DOP_MONITOR_P, Local pid, Remote pid or name, Ref}, which is exactly what's
     needed on the other side... */
  int
  erts_dsig_send_monitor(ErtsDSigData *dsdp, Eterm watcher, Eterm watched,
  		       Eterm ref)
  {
      Eterm ctl;
      DeclareTmpHeapNoproc(ctl_heap,5);
      int res;
  
      UseTmpHeapNoproc(5);
      ctl = TUPLE4(&ctl_heap[0],
  		 make_small(DOP_MONITOR_P),
  		 watcher, watched, ref);
  
      res = dsig_send_ctl(dsdp, ctl, 0);
      UnUseTmpHeapNoproc(5);
      return res;
  }
  
  /* A local process monitoring a remote one wants to stop monitoring, either 
     because of a demonitor bif call or because the local process died. We send
     {DOP_DEMONITOR_P, Local pid, Remote pid or name, ref}, which is once again
     rather redundant as only the ref will be needed on the other side... */
  int
  erts_dsig_send_demonitor(ErtsDSigData *dsdp, Eterm watcher,
  			 Eterm watched, Eterm ref, int force)
  {
      Eterm ctl;
      DeclareTmpHeapNoproc(ctl_heap,5);
      int res;
  
      UseTmpHeapNoproc(5);
      ctl = TUPLE4(&ctl_heap[0],
  		 make_small(DOP_DEMONITOR_P),
  		 watcher, watched, ref);
  
      res = dsig_send_ctl(dsdp, ctl, force);
      UnUseTmpHeapNoproc(5);
      return res;
  }
  
  int
  erts_dsig_send_msg(Eterm remote, Eterm message, ErtsSendContext* ctx)
  {
      Eterm ctl;
      Eterm token = NIL;
      Process *sender = ctx->dsd.proc;
      int res;
  #ifdef USE_VM_PROBES
      Sint tok_label = 0;
      Sint tok_lastcnt = 0;
      Sint tok_serial = 0;
      Uint msize = 0;
      DTRACE_CHARBUF(node_name, 64);
      DTRACE_CHARBUF(sender_name, 64);
      DTRACE_CHARBUF(receiver_name, 64);
  #endif
  
      if (have_seqtrace(SEQ_TRACE_TOKEN(sender))) {
  	seq_trace_update_send(sender);
  	token = SEQ_TRACE_TOKEN(sender);
  	seq_trace_output(token, message, SEQ_TRACE_SEND, remote, sender);
      }
  #ifdef USE_VM_PROBES
      *node_name = *sender_name = *receiver_name = '\0';
      if (DTRACE_ENABLED(message_send) || DTRACE_ENABLED(message_send_remote)) {
          erts_snprintf(node_name, sizeof(DTRACE_CHARBUF_NAME(node_name)),
                        "%T", ctx->dsd.dep->sysname);
          erts_snprintf(sender_name, sizeof(DTRACE_CHARBUF_NAME(sender_name)),
                        "%T", sender->common.id);
          erts_snprintf(receiver_name, sizeof(DTRACE_CHARBUF_NAME(receiver_name)),
                        "%T", remote);
          msize = size_object(message);
          if (have_seqtrace(token)) {
              tok_label = signed_val(SEQ_TRACE_T_LABEL(token));
              tok_lastcnt = signed_val(SEQ_TRACE_T_LASTCNT(token));
              tok_serial = signed_val(SEQ_TRACE_T_SERIAL(token));
          }
      }
  #endif
  
      if (token != NIL)
  	ctl = TUPLE4(&ctx->ctl_heap[0],
  		     make_small(DOP_SEND_TT), am_Empty, remote, token);
      else
  	ctl = TUPLE3(&ctx->ctl_heap[0], make_small(DOP_SEND), am_Empty, remote);
      DTRACE6(message_send, sender_name, receiver_name,
              msize, tok_label, tok_lastcnt, tok_serial);
      DTRACE7(message_send_remote, sender_name, node_name, receiver_name,
              msize, tok_label, tok_lastcnt, tok_serial);
      ctx->dss.ctl = ctl;
      ctx->dss.msg = message;
      ctx->dss.force_busy = 0;
      res = erts_dsig_send(&ctx->dsd, &ctx->dss);
      return res;
  }
  
  int
  erts_dsig_send_reg_msg(Eterm remote_name, Eterm message,
  		       ErtsSendContext* ctx)
  {
      Eterm ctl;
      Eterm token = NIL;
      Process *sender = ctx->dsd.proc;
      int res;
  #ifdef USE_VM_PROBES
      Sint tok_label = 0;
      Sint tok_lastcnt = 0;
      Sint tok_serial = 0;
      Uint32 msize = 0;
      DTRACE_CHARBUF(node_name, 64);
      DTRACE_CHARBUF(sender_name, 64);
      DTRACE_CHARBUF(receiver_name, 128);
  #endif
  
      if (have_seqtrace(SEQ_TRACE_TOKEN(sender))) {
  	seq_trace_update_send(sender);
  	token = SEQ_TRACE_TOKEN(sender);
  	seq_trace_output(token, message, SEQ_TRACE_SEND, remote_name, sender);
      }
  #ifdef USE_VM_PROBES
      *node_name = *sender_name = *receiver_name = '\0';
      if (DTRACE_ENABLED(message_send) || DTRACE_ENABLED(message_send_remote)) {
          erts_snprintf(node_name, sizeof(DTRACE_CHARBUF_NAME(node_name)),
                        "%T", ctx->dsd.dep->sysname);
          erts_snprintf(sender_name, sizeof(DTRACE_CHARBUF_NAME(sender_name)),
                        "%T", sender->common.id);
          erts_snprintf(receiver_name, sizeof(DTRACE_CHARBUF_NAME(receiver_name)),
                        "{%T,%s}", remote_name, node_name);
          msize = size_object(message);
          if (have_seqtrace(token)) {
              tok_label = signed_val(SEQ_TRACE_T_LABEL(token));
              tok_lastcnt = signed_val(SEQ_TRACE_T_LASTCNT(token));
              tok_serial = signed_val(SEQ_TRACE_T_SERIAL(token));
          }
      }
  #endif
  
      if (token != NIL)
  	ctl = TUPLE5(&ctx->ctl_heap[0], make_small(DOP_REG_SEND_TT),
  		     sender->common.id, am_Empty, remote_name, token);
      else
  	ctl = TUPLE4(&ctx->ctl_heap[0], make_small(DOP_REG_SEND),
  		     sender->common.id, am_Empty, remote_name);
      DTRACE6(message_send, sender_name, receiver_name,
              msize, tok_label, tok_lastcnt, tok_serial);
      DTRACE7(message_send_remote, sender_name, node_name, receiver_name,
              msize, tok_label, tok_lastcnt, tok_serial);
      ctx->dss.ctl = ctl;
      ctx->dss.msg = message;
      ctx->dss.force_busy = 0;
      res = erts_dsig_send(&ctx->dsd, &ctx->dss);
      return res;
  }
  
  /* local has died, deliver the exit signal to remote */
  int
  erts_dsig_send_exit_tt(ErtsDSigData *dsdp, Eterm local, Eterm remote, 
  		       Eterm reason, Eterm token)
  {
      Eterm ctl;
      DeclareTmpHeapNoproc(ctl_heap,6);
      int res;
  #ifdef USE_VM_PROBES
      Process *sender = dsdp->proc;
      Sint tok_label = 0;
      Sint tok_lastcnt = 0;
      Sint tok_serial = 0;
      DTRACE_CHARBUF(node_name, 64);
      DTRACE_CHARBUF(sender_name, 64);
      DTRACE_CHARBUF(remote_name, 128);
      DTRACE_CHARBUF(reason_str, 128);
  #endif
  
      UseTmpHeapNoproc(6);
      if (have_seqtrace(token)) {
  	seq_trace_update_send(dsdp->proc);
  	seq_trace_output_exit(token, reason, SEQ_TRACE_SEND, remote, local);
  	ctl = TUPLE5(&ctl_heap[0],
  		     make_small(DOP_EXIT_TT), local, remote, token, reason);
      } else {
  	ctl = TUPLE4(&ctl_heap[0], make_small(DOP_EXIT), local, remote, reason);
      }
  #ifdef USE_VM_PROBES
      *node_name = *sender_name = *remote_name = '\0';
      if (DTRACE_ENABLED(process_exit_signal_remote)) {
          erts_snprintf(node_name, sizeof(DTRACE_CHARBUF_NAME(node_name)),
                        "%T", dsdp->dep->sysname);
          erts_snprintf(sender_name, sizeof(DTRACE_CHARBUF_NAME(sender_name)),
                        "%T", sender->common.id);
          erts_snprintf(remote_name, sizeof(DTRACE_CHARBUF_NAME(remote_name)),
                        "{%T,%s}", remote, node_name);
          erts_snprintf(reason_str, sizeof(DTRACE_CHARBUF_NAME(reason_str)),
                        "%T", reason);
          if (have_seqtrace(token)) {
              tok_label = signed_val(SEQ_TRACE_T_LABEL(token));
              tok_lastcnt = signed_val(SEQ_TRACE_T_LASTCNT(token));
              tok_serial = signed_val(SEQ_TRACE_T_SERIAL(token));
          }
      }
  #endif
      DTRACE7(process_exit_signal_remote, sender_name, node_name,
              remote_name, reason_str, tok_label, tok_lastcnt, tok_serial);
      /* forced, i.e ignore busy */
      res = dsig_send_ctl(dsdp, ctl, 1);
      UnUseTmpHeapNoproc(6);
      return res;
  }
  
  int
  erts_dsig_send_exit(ErtsDSigData *dsdp, Eterm local, Eterm remote, Eterm reason)
  {
      DeclareTmpHeapNoproc(ctl_heap,5);
      int res;
      Eterm ctl;
  
      UseTmpHeapNoproc(5);
      ctl = TUPLE4(&ctl_heap[0],
  		 make_small(DOP_EXIT), local, remote, reason);
      /* forced, i.e ignore busy */
      res =  dsig_send_ctl(dsdp, ctl, 1);
      UnUseTmpHeapNoproc(5);
      return res;
  }
  
  int
  erts_dsig_send_exit2(ErtsDSigData *dsdp, Eterm local, Eterm remote, Eterm reason)
  {
      DeclareTmpHeapNoproc(ctl_heap,5);
      int res;
      Eterm ctl;
  
      UseTmpHeapNoproc(5);
      ctl = TUPLE4(&ctl_heap[0],
  		 make_small(DOP_EXIT2), local, remote, reason);
  
      res = dsig_send_ctl(dsdp, ctl, 0);
      UnUseTmpHeapNoproc(5);
      return res;
  }
  
  
  int
  erts_dsig_send_group_leader(ErtsDSigData *dsdp, Eterm leader, Eterm remote)
  {
      DeclareTmpHeapNoproc(ctl_heap,4);
      int res;
      Eterm ctl;
  
      UseTmpHeapNoproc(4);
      ctl = TUPLE3(&ctl_heap[0],
  		 make_small(DOP_GROUP_LEADER), leader, remote);
  
      res = dsig_send_ctl(dsdp, ctl, 0);
      UnUseTmpHeapNoproc(4);
      return res;
  }
  
  #if defined(PURIFY)
  #  define PURIFY_MSG(msg) \
      purify_printf("%s, line %d: %s", __FILE__, __LINE__, msg)
  #elif defined(VALGRIND)
  #include <valgrind/valgrind.h>
  #include <valgrind/memcheck.h>
  
  #ifndef HAVE_VALGRIND_PRINTF_XML
  #define VALGRIND_PRINTF_XML VALGRIND_PRINTF
  #endif
  
  #  define PURIFY_MSG(msg)                                                    \
      do {								     \
  	char buf__[1]; size_t bufsz__ = sizeof(buf__);			     \
  	if (erts_sys_getenv_raw("VALGRIND_LOG_XML", buf__, &bufsz__) >= 0) { \
  	    VALGRIND_PRINTF_XML("<erlang_error_log>"			     \
  			    "%s, line %d: %s</erlang_error_log>\n",	     \
  			    __FILE__, __LINE__, msg);			     \
  	} else {							     \
  	    VALGRIND_PRINTF("%s, line %d: %s", __FILE__, __LINE__, msg);     \
  	}								     \
      } while (0)
  #else
  #  define PURIFY_MSG(msg)
  #endif
  
  /*
  ** Input from distribution port.
  **  Input follows the distribution protocol v4.5
  **  
  **   The protocol is a 4 byte header protocol
  **   the DOP_DATA is stripped by driver_output
  **
  **   assert  hlen == 0 !!!
  */
  
  int erts_net_message(Port *prt,
  		     DistEntry *dep,
  		     byte *hbuf,
  		     ErlDrvSizeT hlen,
  		     byte *buf,
  		     ErlDrvSizeT len)
  {
      ErtsDistExternal ede;
      byte *t;
      Sint ctl_len;
      Eterm arg;
      Eterm from, to;
      Eterm watcher, watched;
      Eterm ref;
      Eterm *tuple;
      Eterm reason;
      Process* rp;
      DeclareTmpHeapNoproc(ctl_default,DIST_CTL_DEFAULT_SIZE);
      Eterm* ctl = ctl_default;
      ErtsHeapFactory factory;
      Eterm* hp;
      Sint type;
      Eterm token;
      Eterm token_size;
      ErtsMonitor *mon;
      ErtsLink *lnk;
      Uint tuple_arity;
      int res;
  #ifdef ERTS_DIST_MSG_DBG
      ErlDrvSizeT orig_len = len;
  #endif
  
      UseTmpHeapNoproc(DIST_CTL_DEFAULT_SIZE);
  
      ERTS_SMP_CHK_NO_PROC_LOCKS;
  
      ERTS_SMP_LC_ASSERT(erts_lc_is_port_locked(prt));
  
      if (!erts_is_alive) {
  	UnUseTmpHeapNoproc(DIST_CTL_DEFAULT_SIZE);
  	return 0;
      }
      if (hlen != 0)
  	goto data_error;
      if (len == 0) {  /* HANDLE TICK !!! */
  	UnUseTmpHeapNoproc(DIST_CTL_DEFAULT_SIZE);
  	return 0;
      }
  
  #ifdef ERTS_RAW_DIST_MSG_DBG
      erts_fprintf(stderr, "<< ");
      bw(buf, len);
  #endif
  
      if (dep->flags & DFLAG_DIST_HDR_ATOM_CACHE)
  	t = buf;
      else {
  	/* Skip PASS_THROUGH */
  	t = buf+1;
  	len--;
      }
  
      if (len == 0) {
  	PURIFY_MSG("data error");
  	goto data_error;
      }
  
      res = erts_prepare_dist_ext(&ede, t, len, dep, dep->cache);
  
      if (res >= 0)
  	res = ctl_len = erts_decode_dist_ext_size(&ede);
      else {
  #ifdef ERTS_DIST_MSG_DBG
  	erts_fprintf(stderr, "DIST MSG DEBUG: erts_prepare_dist_ext() failed:\n");
  	bw(buf, orig_len);
  #endif
  	ctl_len = 0;
      }
  
      if (res < 0) {
  #ifdef ERTS_DIST_MSG_DBG
  	erts_fprintf(stderr, "DIST MSG DEBUG: erts_decode_dist_ext_size(CTL) failed:\n");
  	bw(buf, orig_len);
  #endif
  	PURIFY_MSG("data error");
  	goto data_error;
      }
  
      if (ctl_len > DIST_CTL_DEFAULT_SIZE) {
  	ctl = erts_alloc(ERTS_ALC_T_DCTRL_BUF, ctl_len * sizeof(Eterm));
      }
      hp = ctl;
  
      erts_factory_tmp_init(&factory, ctl, ctl_len, ERTS_ALC_T_DCTRL_BUF);
      arg = erts_decode_dist_ext(&factory, &ede);
      if (is_non_value(arg)) {
  #ifdef ERTS_DIST_MSG_DBG
  	erts_fprintf(stderr, "DIST MSG DEBUG: erts_decode_dist_ext(CTL) failed:\n");
  	bw(buf, orig_len);
  #endif
  	PURIFY_MSG("data error");
  	goto decode_error;
      }
      ctl_len = t - buf;
  
  #ifdef ERTS_DIST_MSG_DBG
      erts_fprintf(stderr, "<<%s CTL: %T\n", len != orig_len ? "P" : " ", arg);
  #endif
  
      if (is_not_tuple(arg) || 
  	(tuple = tuple_val(arg), (tuple_arity = arityval(*tuple)) < 1) ||
  	is_not_small(tuple[1])) {
   	goto invalid_message;
      }
  
      token_size = 0;
  
      switch (type = unsigned_val(tuple[1])) {
      case DOP_LINK:
  	if (tuple_arity != 3) {
  	    goto invalid_message;
  	}
  	from = tuple[2];
  	to   = tuple[3];  /* local proc to link to */
  
  	if (is_not_pid(from) || is_not_pid(to)) {
  	    goto invalid_message;
  	}
  
  	rp = erts_pid2proc_opt(NULL, 0,
  			       to, ERTS_PROC_LOCK_LINK,
  			       ERTS_P2P_FLG_ALLOW_OTHER_X);
  	if (!rp) {
  	    /* This is tricky (we MUST force a distributed send) */
  	    ErtsDSigData dsd;
  	    int code;
  	    code = erts_dsig_prepare(&dsd, dep, NULL, ERTS_DSP_NO_LOCK, 0);
  	    if (code == ERTS_DSIG_PREP_CONNECTED) {
  		code = erts_dsig_send_exit(&dsd, to, from, am_noproc);
  		ASSERT(code == ERTS_DSIG_SEND_OK);
  	    }
  	    break;
  	}
  
  	erts_smp_de_links_lock(dep);
  	res = erts_add_link(&ERTS_P_LINKS(rp), LINK_PID, from);
  
  	if (res < 0) {
  	    /* It was already there! Lets skip the rest... */
  	    erts_smp_de_links_unlock(dep);
  	    erts_smp_proc_unlock(rp, ERTS_PROC_LOCK_LINK);
  	    break;
  	}
  	lnk = erts_add_or_lookup_link(&(dep->nlinks), LINK_PID, rp->common.id);
  	erts_add_link(&(ERTS_LINK_ROOT(lnk)), LINK_PID, from);
  	erts_smp_de_links_unlock(dep);
  
  	if (IS_TRACED_FL(rp, F_TRACE_PROCS))
  	    trace_proc(NULL, 0, rp, am_getting_linked, from);
  
  	erts_smp_proc_unlock(rp, ERTS_PROC_LOCK_LINK);
  	break;
  
      case DOP_UNLINK: {
  	ErtsDistLinkData dld;
  	if (tuple_arity != 3) {
  	    goto invalid_message;
  	}
  	from = tuple[2];
  	to = tuple[3];
  	if (is_not_pid(from) || is_not_pid(to)) {
  	    goto invalid_message;
  	}
  	
  	rp = erts_pid2proc_opt(NULL, 0,
  			       to, ERTS_PROC_LOCK_LINK,
  			       ERTS_P2P_FLG_ALLOW_OTHER_X);
  	if (!rp)
  	    break;
  
  	lnk = erts_remove_link(&ERTS_P_LINKS(rp), from);
  
  	if (IS_TRACED_FL(rp, F_TRACE_PROCS) && lnk != NULL) {
  	    trace_proc(NULL, 0, rp, am_getting_unlinked, from);
  	}
  
  	erts_smp_proc_unlock(rp, ERTS_PROC_LOCK_LINK);
  
  	erts_remove_dist_link(&dld, to, from, dep);
  	erts_destroy_dist_link(&dld);
  	if (lnk)
  	    erts_destroy_link(lnk);
  	break;
      }
      
      case DOP_MONITOR_P: {
  	/* A remote process wants to monitor us, we get:
  	   {DOP_MONITOR_P, Remote pid, local pid or name, ref} */
  	Eterm name;
  	
  	if (tuple_arity != 4) {
  	    goto invalid_message;
  	}
  
  	watcher = tuple[2];
  	watched = tuple[3];  /* local proc to monitor */
  	ref     = tuple[4];
  
  	if (is_not_ref(ref)) {
  	    goto invalid_message;
  	}
  
  	if (is_atom(watched)) {
  	    name = watched;
  	    rp = erts_whereis_process(NULL, 0,
  				      watched, ERTS_PROC_LOCK_LINK,
  				      ERTS_P2P_FLG_ALLOW_OTHER_X);
  	}
  	else {
  	    name = NIL;
  	    rp = erts_pid2proc_opt(NULL, 0,
  				   watched, ERTS_PROC_LOCK_LINK,
  				   ERTS_P2P_FLG_ALLOW_OTHER_X);
  	}
  
  	if (!rp) {
  	    ErtsDSigData dsd;
  	    int code;
  	    code = erts_dsig_prepare(&dsd, dep, NULL, ERTS_DSP_NO_LOCK, 0);
  	    if (code == ERTS_DSIG_PREP_CONNECTED) {
  		code = erts_dsig_send_m_exit(&dsd, watcher, watched, ref,
  					     am_noproc);
  		ASSERT(code == ERTS_DSIG_SEND_OK);
  	    }
  	}
  	else {
  	    if (is_atom(watched))
  		watched = rp->common.id;
  	    erts_smp_de_links_lock(dep);
  	    erts_add_monitor(&(dep->monitors), MON_ORIGIN, ref, watched, name);
  	    erts_add_monitor(&ERTS_P_MONITORS(rp), MON_TARGET, ref, watcher, name);
  	    erts_smp_de_links_unlock(dep);
  	    erts_smp_proc_unlock(rp, ERTS_PROC_LOCK_LINK);
  	}
  
  	break;
      }
  
      case DOP_DEMONITOR_P:
  	/* A remote node informs us that a local pid in no longer monitored
  	   We get {DOP_DEMONITOR_P, Remote pid, Local pid or name, ref},
  	   We need only the ref of course */
  
  	if (tuple_arity != 4) {
  	    goto invalid_message;
  	}
  	/* watcher = tuple[2]; */
  	/* watched = tuple[3]; May be an atom in case of monitor name */
  	ref = tuple[4];
  
  	if(is_not_ref(ref)) {
  	    goto invalid_message;
  	}
  
  	erts_smp_de_links_lock(dep);
  	mon = erts_remove_monitor(&(dep->monitors),ref);
  	erts_smp_de_links_unlock(dep);
  	/* ASSERT(mon != NULL); can happen in case of broken dist message */
  	if (mon == NULL) {
  	    break;
  	}
  	watched = mon->u.pid;
  	erts_destroy_monitor(mon);
  	rp = erts_pid2proc_opt(NULL, 0,
  			       watched, ERTS_PROC_LOCK_LINK,
  			       ERTS_P2P_FLG_ALLOW_OTHER_X);
  	if (!rp) {
  	    break;
  	}
  	mon = erts_remove_monitor(&ERTS_P_MONITORS(rp), ref);
  	erts_smp_proc_unlock(rp, ERTS_PROC_LOCK_LINK);
  	ASSERT(mon != NULL);
  	if (mon == NULL) {
  	    break;
  	}
  	erts_destroy_monitor(mon);
  	break;
  
      case DOP_REG_SEND_TT:
  	if (tuple_arity != 5) {
  	    goto invalid_message;
  	}
  
  	token_size = size_object(tuple[5]);
  	/* Fall through ... */
      case DOP_REG_SEND:
  	/* {DOP_REG_SEND, From, Cookie, ToName} -- Message */
  	/* {DOP_REG_SEND_TT, From, Cookie, ToName, TraceToken} -- Message */
  
  	/*
  	 * There is intentionally no testing of the cookie (it is always '')
  	 * from R9B and onwards.
  	 */
  	if (type != DOP_REG_SEND_TT && tuple_arity != 4) {
  	    goto invalid_message;
  	}
  
  #ifdef ERTS_DIST_MSG_DBG
  	dist_msg_dbg(&ede, "MSG", buf, orig_len);
  #endif
  
  	from = tuple[2];
  	to = tuple[4];
  	if (is_not_pid(from) || is_not_atom(to)){
  	    goto invalid_message;
  	}
  	rp = erts_whereis_process(NULL, 0, to, 0, 0);
  	if (rp) {
  	    Uint xsize = (type == DOP_REG_SEND
  			  ? 0
  			  : ERTS_HEAP_FRAG_SIZE(token_size));
  	    ErtsProcLocks locks = 0;
  	    ErtsDistExternal *ede_copy;
  
  	    ede_copy = erts_make_dist_ext_copy(&ede, xsize);
  	    if (type == DOP_REG_SEND) {
  		token = NIL;
  	    } else {
  		ErlHeapFragment *heap_frag;
  		ErlOffHeap *ohp;
  		ASSERT(xsize);
  		heap_frag = erts_dist_ext_trailer(ede_copy);
  		ERTS_INIT_HEAP_FRAG(heap_frag, token_size, token_size);
  		hp = heap_frag->mem;
  		ohp = &heap_frag->off_heap;
  		token = tuple[5];
  		token = copy_struct(token, token_size, &hp, ohp);
  	    }
  
  	    erts_queue_dist_message(rp, locks, ede_copy, token, from);
  	    if (locks)
  		erts_smp_proc_unlock(rp, locks);
  	}
  	break;
  
      case DOP_SEND_TT:
  	if (tuple_arity != 4) {
  	    goto invalid_message;
  	}
  	
  	token_size = size_object(tuple[4]);
  	/* Fall through ... */
      case DOP_SEND:
  	/*
  	 * There is intentionally no testing of the cookie (it is always '')
  	 * from R9B and onwards.
  	 */
  #ifdef ERTS_DIST_MSG_DBG
  	dist_msg_dbg(&ede, "MSG", buf, orig_len);
  #endif
  	if (type != DOP_SEND_TT && tuple_arity != 3) {
  	    goto invalid_message;
  	}
  	to = tuple[3];
  	if (is_not_pid(to)) {
  	    goto invalid_message;
  	}
  	rp = erts_proc_lookup(to);
  	if (rp) {
  	    Uint xsize = type == DOP_SEND ? 0 : ERTS_HEAP_FRAG_SIZE(token_size);
  	    ErtsProcLocks locks = 0;
  	    ErtsDistExternal *ede_copy;
  
  	    ede_copy = erts_make_dist_ext_copy(&ede, xsize);
  	    if (type == DOP_SEND) {
  		token = NIL;
  	    } else {
  		ErlHeapFragment *heap_frag;
  		ErlOffHeap *ohp;
  		ASSERT(xsize);
  		heap_frag = erts_dist_ext_trailer(ede_copy);
  		ERTS_INIT_HEAP_FRAG(heap_frag, token_size, token_size);
  		hp = heap_frag->mem;
  		ohp = &heap_frag->off_heap;
  		token = tuple[4];
  		token = copy_struct(token, token_size, &hp, ohp);
  	    }
  
  	    erts_queue_dist_message(rp, locks, ede_copy, token, tuple[2]);
  	    if (locks)
  		erts_smp_proc_unlock(rp, locks);
  	}
  	break;
  
      case DOP_MONITOR_P_EXIT: {
  	/* We are monitoring a process on the remote node which dies, we get
  	   {DOP_MONITOR_P_EXIT, Remote pid or name, Local pid, ref, reason} */
  	   
  
  	DeclareTmpHeapNoproc(lhp,3);
  	Eterm sysname;
  	ErtsProcLocks rp_locks = ERTS_PROC_LOCKS_MSG_SEND|ERTS_PROC_LOCK_LINK;
  
  	if (tuple_arity != 5) {
  	    goto invalid_message;
  	}
  
  	/* watched = tuple[2]; */  /* remote proc which died */
  	/* watcher = tuple[3]; */
  	ref     = tuple[4];
  	reason  = tuple[5];
  
  	if(is_not_ref(ref)) {
  	    goto invalid_message;
  	}
  
  	erts_smp_de_links_lock(dep);
  	sysname = dep->sysname;
  	mon = erts_remove_monitor(&(dep->monitors), ref);
  	/*
  	 * If demonitor was performed at the same time as the
  	 * monitored process exits, monitoring side will have
  	 * removed info about monitor. In this case, do nothing
  	 * and everything will be as it should.
  	 */
  	erts_smp_de_links_unlock(dep);
  	if (mon == NULL) {
  	    break;
  	}
  	rp = erts_pid2proc(NULL, 0, mon->u.pid, rp_locks);
  
  	erts_destroy_monitor(mon);
  	if (rp == NULL) {
  	    break;
  	}
  
  	mon = erts_remove_monitor(&ERTS_P_MONITORS(rp), ref);
  
  	if (mon == NULL) {
  	    erts_smp_proc_unlock(rp, rp_locks);
  	    break;
  	}
  	UseTmpHeapNoproc(3);
  	
  	watched = (is_not_nil(mon->name)
  		   ? TUPLE2(&lhp[0], mon->name, sysname)
  		   : mon->u.pid);
  	
  	erts_queue_monitor_message(rp, &rp_locks,
  				   ref, am_process, watched, reason);
  	erts_smp_proc_unlock(rp, rp_locks);
  	erts_destroy_monitor(mon);
  	UnUseTmpHeapNoproc(3);
  	break;
      }
  
      case DOP_EXIT_TT:
      case DOP_EXIT: {
  	ErtsDistLinkData dld;
  	ErtsProcLocks rp_locks = ERTS_PROC_LOCK_LINK|ERTS_PROC_LOCKS_XSIG_SEND;
  	/* 'from', which 'to' is linked to, died */
  	if (type == DOP_EXIT) {
  	    if (tuple_arity != 4) {
  		goto invalid_message;
  	    }
  	    
  	    from = tuple[2];
  	    to = tuple[3];
  	    reason = tuple[4];
  	    token = NIL;
  	} else {
  	    if (tuple_arity != 5) {
  		goto invalid_message;
  	    }
  	    from = tuple[2];
  	    to = tuple[3];
  	    token = tuple[4];
  	    reason = tuple[5];
  	}
  	if (is_not_pid(from) || is_not_internal_pid(to)) {
  	    goto invalid_message;
  	}
  
  	rp = erts_pid2proc(NULL, 0, to, rp_locks);
  	if (!rp)
  	    lnk = NULL;
  	else {
  	    lnk = erts_remove_link(&ERTS_P_LINKS(rp), from);
  
  	    /* If lnk == NULL, we have unlinked on this side, i.e.
  	     * ignore exit.
  	     */
  	    if (lnk) {
  		int xres;
  #if 0
  		/* Arndt: Maybe it should never be 'kill', but it can be,
  		   namely when a linked process does exit(kill). Until we know
  		   whether that is incorrect and what should happen instead,
  		   we leave the assertion out. */
  		ASSERT(reason != am_kill); /* should never be kill (killed) */
  #endif
  		xres = erts_send_exit_signal(NULL,
  					     from,
  					     rp,
  					     &rp_locks, 
  					     reason,
  					     token,
  					     NULL,
  					     ERTS_XSIG_FLG_IGN_KILL);
  		if (xres >= 0 && IS_TRACED_FL(rp, F_TRACE_PROCS)) {
  		    /* We didn't exit the process and it is traced */
                      if (rp_locks & ERTS_PROC_LOCKS_XSIG_SEND) {
                          erts_smp_proc_unlock(rp, ERTS_PROC_LOCKS_XSIG_SEND);
                          rp_locks &= ~ERTS_PROC_LOCKS_XSIG_SEND;
                      }
  		    trace_proc(NULL, 0, rp, am_getting_unlinked, from);
  		}
  	    }
  	    erts_smp_proc_unlock(rp, rp_locks);
  	}
  	erts_remove_dist_link(&dld, to, from, dep);
  	if (lnk)
  	    erts_destroy_link(lnk);
  	erts_destroy_dist_link(&dld);
  	break;
      }
      case DOP_EXIT2_TT:
      case DOP_EXIT2: {
  	ErtsProcLocks rp_locks = ERTS_PROC_LOCKS_XSIG_SEND;
  	/* 'from' is send an exit signal to 'to' */
  	if (type == DOP_EXIT2) {
  	    if (tuple_arity != 4) {
  		goto invalid_message;
  	    }
  	    from = tuple[2];
  	    to = tuple[3];
  	    reason = tuple[4];
  	    token = NIL;
  	} else {
  	    if (tuple_arity != 5) {
  		goto invalid_message;
  	    }
  	    from = tuple[2];
  	    to = tuple[3];
  	    token = tuple[4];
  	    reason = tuple[5];
  	}
  	if (is_not_pid(from) || is_not_internal_pid(to)) {
  	    goto invalid_message;
  	}
  	rp = erts_pid2proc(NULL, 0, to, rp_locks);
  	if (rp) {
  	    (void) erts_send_exit_signal(NULL,
  					 from,
  					 rp,
  					 &rp_locks,
  					 reason,
  					 token,
  					 NULL,
  					 0);
  	    erts_smp_proc_unlock(rp, rp_locks);
  	}
  	break;
      }
      case DOP_GROUP_LEADER:
  	if (tuple_arity != 3) {
  	    goto invalid_message;
  	}
  	from = tuple[2];   /* Group leader  */
  	to = tuple[3];     /* new member */
  	if (is_not_pid(from) || is_not_pid(to)) {
  	    goto invalid_message;
  	}
  
  	rp = erts_pid2proc(NULL, 0, to, ERTS_PROC_LOCK_MAIN);
  	if (!rp)
  	    break;
  	rp->group_leader = STORE_NC_IN_PROC(rp, from);
  	erts_smp_proc_unlock(rp, ERTS_PROC_LOCK_MAIN);
  	break;
  
      default: 
  	goto invalid_message;
      }
  
      erts_factory_close(&factory);
      if (ctl != ctl_default) {
  	erts_free(ERTS_ALC_T_DCTRL_BUF, (void *) ctl);
      }
      UnUseTmpHeapNoproc(DIST_CTL_DEFAULT_SIZE);
      ERTS_SMP_CHK_NO_PROC_LOCKS;
      return 0;
   invalid_message:
      {
  	erts_dsprintf_buf_t *dsbufp = erts_create_logger_dsbuf();
  	erts_dsprintf(dsbufp, "Invalid distribution message: %.200T", arg);
  	erts_send_error_to_logger_nogl(dsbufp);
      }
  decode_error:
      PURIFY_MSG("data error");
      erts_factory_close(&factory);
      if (ctl != ctl_default) {
  	erts_free(ERTS_ALC_T_DCTRL_BUF, (void *) ctl);
      }
  data_error:
      UnUseTmpHeapNoproc(DIST_CTL_DEFAULT_SIZE);
      erts_deliver_port_exit(prt, dep->cid, am_killed, 0, 1);
      ERTS_SMP_CHK_NO_PROC_LOCKS;
      return -1;
  }
  
  static int dsig_send_ctl(ErtsDSigData* dsdp, Eterm ctl, int force_busy)
  {
      struct erts_dsig_send_context ctx;
      int ret;
      ctx.ctl = ctl;
      ctx.msg = THE_NON_VALUE;
      ctx.force_busy = force_busy;
      ctx.phase = ERTS_DSIG_SEND_PHASE_INIT;
  #ifdef DEBUG
      ctx.reds = 1; /* provoke assert below (no reduction count without msg) */
  #endif
      ret = erts_dsig_send(dsdp, &ctx);
      ASSERT(ret != ERTS_DSIG_SEND_CONTINUE);
      return ret;
  }
  
  int
  erts_dsig_send(ErtsDSigData *dsdp, struct erts_dsig_send_context* ctx)
  {
      int retval;
      Sint initial_reds = ctx->reds;
      Eterm cid;
  
      while (1) {
  	switch (ctx->phase) {
  	case ERTS_DSIG_SEND_PHASE_INIT:
  	    ctx->flags = dsdp->dep->flags;
  	    ctx->c_p = dsdp->proc;
  
  	    if (!ctx->c_p || dsdp->no_suspend)
  		ctx->force_busy = 1;
  
  	    ERTS_SMP_LC_ASSERT(!ctx->c_p
  			       || (ERTS_PROC_LOCK_MAIN
  				   == erts_proc_lc_my_proc_locks(ctx->c_p)));
  
  	    if (!erts_is_alive)
  		return ERTS_DSIG_SEND_OK;
  
  	    if (ctx->flags & DFLAG_DIST_HDR_ATOM_CACHE) {
  		ctx->acmp = erts_get_atom_cache_map(ctx->c_p);
  		ctx->pass_through_size = 0;
  	    }
  	    else {
  		ctx->acmp = NULL;
  		ctx->pass_through_size = 1;
  	    }
  
      #ifdef ERTS_DIST_MSG_DBG
  	    erts_fprintf(stderr, ">>%s CTL: %T\n", ctx->pass_through_size ? "P" : " ", ctx->ctl);
          if (is_value(ctx->msg))
              erts_fprintf(stderr, "    MSG: %T\n", ctx->msg);
      #endif
  
  	    ctx->data_size = ctx->pass_through_size;
  	    erts_reset_atom_cache_map(ctx->acmp);
  	    erts_encode_dist_ext_size(ctx->ctl, ctx->flags, ctx->acmp, &ctx->data_size);
  
  	    if (is_value(ctx->msg)) {
  		ctx->u.sc.wstack.wstart = NULL;
  		ctx->u.sc.flags = ctx->flags;
  		ctx->u.sc.level = 0;
  		ctx->phase = ERTS_DSIG_SEND_PHASE_MSG_SIZE;
  	    } else {
  		ctx->phase = ERTS_DSIG_SEND_PHASE_ALLOC;
  	    }
  	    break;
  
  	case ERTS_DSIG_SEND_PHASE_MSG_SIZE:
  	    if (erts_encode_dist_ext_size_int(ctx->msg, ctx, &ctx->data_size)) {
  		retval = ERTS_DSIG_SEND_CONTINUE;
  		goto done;
  	    }
  
  	    ctx->phase = ERTS_DSIG_SEND_PHASE_ALLOC;
  	case ERTS_DSIG_SEND_PHASE_ALLOC:
  	    erts_finalize_atom_cache_map(ctx->acmp, ctx->flags);
  
  	    ctx->dhdr_ext_size = erts_encode_ext_dist_header_size(ctx->acmp);
  	    ctx->data_size += ctx->dhdr_ext_size;
  
  	    ctx->obuf = alloc_dist_obuf(ctx->data_size);
  	    ctx->obuf->ext_endp = &ctx->obuf->data[0] + ctx->pass_through_size + ctx->dhdr_ext_size;
  
  	    /* Encode internal version of dist header */
  	    ctx->obuf->extp = erts_encode_ext_dist_header_setup(ctx->obuf->ext_endp, ctx->acmp);
  	    /* Encode control message */
  	    erts_encode_dist_ext(ctx->ctl, &ctx->obuf->ext_endp, ctx->flags, ctx->acmp, NULL, NULL);
  	    if (is_value(ctx->msg)) {
  		ctx->u.ec.flags = ctx->flags;
  		ctx->u.ec.level = 0;
  		ctx->u.ec.wstack.wstart = NULL;
  		ctx->phase = ERTS_DSIG_SEND_PHASE_MSG_ENCODE;
  	    } else {
  		ctx->phase = ERTS_DSIG_SEND_PHASE_FIN;
  	    }
  	    break;
  
  	case ERTS_DSIG_SEND_PHASE_MSG_ENCODE:
  	    if (erts_encode_dist_ext(ctx->msg, &ctx->obuf->ext_endp, ctx->flags, ctx->acmp, &ctx->u.ec, &ctx->reds)) {
  		retval = ERTS_DSIG_SEND_CONTINUE;
  		goto done;
  	    }
  
  	    ctx->phase = ERTS_DSIG_SEND_PHASE_FIN;
  	case ERTS_DSIG_SEND_PHASE_FIN: {
  	    DistEntry *dep = dsdp->dep;
  	    int suspended = 0;
  	    int resume = 0;
  
  	    ASSERT(ctx->obuf->extp < ctx->obuf->ext_endp);
  	    ASSERT(&ctx->obuf->data[0] <= ctx->obuf->extp - ctx->pass_through_size);
  	    ASSERT(ctx->obuf->ext_endp <= &ctx->obuf->data[0] + ctx->data_size);
  
  	    ctx->data_size = ctx->obuf->ext_endp - ctx->obuf->extp;
  
  	    /*
  	     * Signal encoded; now verify that the connection still exists,
  	     * and if so enqueue the signal and schedule it for send.
  	     */
  	    ctx->obuf->next = NULL;
  	    erts_smp_de_rlock(dep);
  	    cid = dep->cid;
  	    if (cid != dsdp->cid
  		|| dep->connection_id != dsdp->connection_id
  		|| dep->status & ERTS_DE_SFLG_EXITING) {
  		/* Not the same connection as when we started; drop message... */
  		erts_smp_de_runlock(dep);
  		free_dist_obuf(ctx->obuf);
  	    }
  	    else {
  		ErtsProcList *plp = NULL;
  		erts_smp_mtx_lock(&dep->qlock);
  		dep->qsize += size_obuf(ctx->obuf);
  		if (dep->qsize >= erts_dist_buf_busy_limit)
  		    dep->qflgs |= ERTS_DE_QFLG_BUSY;
  		if (!ctx->force_busy && (dep->qflgs & ERTS_DE_QFLG_BUSY)) {
  		    erts_smp_mtx_unlock(&dep->qlock);
  
  		    plp = erts_proclist_create(ctx->c_p);
  		    erts_suspend(ctx->c_p, ERTS_PROC_LOCK_MAIN, NULL);
  		    suspended = 1;
  		    erts_smp_mtx_lock(&dep->qlock);
  		}
  
  		/* Enqueue obuf on dist entry */
  		if (dep->out_queue.last)
  		    dep->out_queue.last->next = ctx->obuf;
  		else
  		    dep->out_queue.first = ctx->obuf;
  		dep->out_queue.last = ctx->obuf;
  
  		if (!ctx->force_busy) {
  		    if (!(dep->qflgs & ERTS_DE_QFLG_BUSY)) {
  			if (suspended)
  			    resume = 1; /* was busy when we started, but isn't now */
      #ifdef USE_VM_PROBES
  			if (resume && DTRACE_ENABLED(dist_port_not_busy)) {
  			    DTRACE_CHARBUF(port_str, 64);
  			    DTRACE_CHARBUF(remote_str, 64);
  
  			    erts_snprintf(port_str, sizeof(DTRACE_CHARBUF_NAME(port_str)),
  					  "%T", cid);
  			    erts_snprintf(remote_str, sizeof(DTRACE_CHARBUF_NAME(remote_str)),
  					  "%T", dep->sysname);
  			    DTRACE3(dist_port_not_busy, erts_this_node_sysname,
  				    port_str, remote_str);
  			}
      #endif
  		    }
  		    else {
  			/* Enqueue suspended process on dist entry */
  			ASSERT(plp);
  			erts_proclist_store_last(&dep->suspended, plp);
  		    }
  		}
  
  		erts_smp_mtx_unlock(&dep->qlock);
  		erts_schedule_dist_command(NULL, dep);
  		erts_smp_de_runlock(dep);
  
  		if (resume) {
  		    erts_resume(ctx->c_p, ERTS_PROC_LOCK_MAIN);
  		    erts_proclist_destroy(plp);
  		    /*
  		     * Note that the calling process still have to yield as if it
  		     * suspended. If not, the calling process could later be
  		     * erroneously scheduled when it shouldn't be.
  		     */
  		}
  	    }
  	    ctx->obuf = NULL;
  
  	    if (suspended) {
      #ifdef USE_VM_PROBES
  		if (!resume && DTRACE_ENABLED(dist_port_busy)) {
  		    DTRACE_CHARBUF(port_str, 64);
  		    DTRACE_CHARBUF(remote_str, 64);
  		    DTRACE_CHARBUF(pid_str, 16);
  
  		    erts_snprintf(port_str, sizeof(DTRACE_CHARBUF_NAME(port_str)), "%T", cid);
  		    erts_snprintf(remote_str, sizeof(DTRACE_CHARBUF_NAME(remote_str)),
  				  "%T", dep->sysname);
  		    erts_snprintf(pid_str, sizeof(DTRACE_CHARBUF_NAME(pid_str)),
  				  "%T", ctx->c_p->common.id);
  		    DTRACE4(dist_port_busy, erts_this_node_sysname,
  			    port_str, remote_str, pid_str);
  		}
      #endif
  		if (!resume && erts_system_monitor_flags.busy_dist_port)
  		    monitor_generic(ctx->c_p, am_busy_dist_port, cid);
  		retval = ERTS_DSIG_SEND_YIELD;
  	    } else {
  		retval = ERTS_DSIG_SEND_OK;
  	    }
  	    goto done;
  	}
  	default:
  	    erts_exit(ERTS_ABORT_EXIT, "dsig_send invalid phase (%d)\n", (int)ctx->phase);
  	}
      }
  
  done:
      if (ctx->msg && ctx->c_p) {
  	BUMP_REDS(ctx->c_p, (initial_reds - ctx->reds) / TERM_TO_BINARY_LOOP_FACTOR);
      }
      return retval;
  }
  
  static Uint
  dist_port_command(Port *prt, ErtsDistOutputBuf *obuf)
  {
      int fpe_was_unmasked;
      Uint size = obuf->ext_endp - obuf->extp;
  
      ERTS_SMP_CHK_NO_PROC_LOCKS;
      ERTS_SMP_LC_ASSERT(erts_lc_is_port_locked(prt));
  
      if (size > (Uint) INT_MAX)
  	erts_exit(ERTS_DUMP_EXIT,
  		 "Absurdly large distribution output data buffer "
  		 "(%beu bytes) passed.\n",
  		 size);
  
  #ifdef USE_VM_PROBES
      if (DTRACE_ENABLED(dist_output)) {
          DTRACE_CHARBUF(port_str, 64);
          DTRACE_CHARBUF(remote_str, 64);
  
          erts_snprintf(port_str, sizeof(DTRACE_CHARBUF_NAME(port_str)),
                        "%T", prt->common.id);
          erts_snprintf(remote_str, sizeof(DTRACE_CHARBUF_NAME(remote_str)),
                        "%T", prt->dist_entry->sysname);
          DTRACE4(dist_output, erts_this_node_sysname, port_str,
                  remote_str, size);
      }
  #endif
      prt->caller = NIL;
      fpe_was_unmasked = erts_block_fpe();
      (*prt->drv_ptr->output)((ErlDrvData) prt->drv_data,
  			    (char*) obuf->extp,
  			    (int) size);
      erts_unblock_fpe(fpe_was_unmasked);
      return size;
  }
  
  static Uint
  dist_port_commandv(Port *prt, ErtsDistOutputBuf *obuf)
  {
      int fpe_was_unmasked;
      Uint size = obuf->ext_endp - obuf->extp;
      SysIOVec iov[2];
      ErlDrvBinary* bv[2];
      ErlIOVec eiov;
  
      ERTS_SMP_CHK_NO_PROC_LOCKS;
      ERTS_SMP_LC_ASSERT(erts_lc_is_port_locked(prt));
  
      if (size > (Uint) INT_MAX)
  	erts_exit(ERTS_DUMP_EXIT,
  		 "Absurdly large distribution output data buffer "
  		 "(%beu bytes) passed.\n",
  		 size);
  
      iov[0].iov_base = NULL;
      iov[0].iov_len = 0;
      bv[0] = NULL;
  
      iov[1].iov_base = obuf->extp;
      iov[1].iov_len = size;
      bv[1] = Binary2ErlDrvBinary(ErtsDistOutputBuf2Binary(obuf));
  
      eiov.vsize = 2;
      eiov.size = size;
      eiov.iov = iov;
      eiov.binv = bv;
  
      ASSERT(prt->drv_ptr->outputv);
  
  #ifdef USE_VM_PROBES
      if (DTRACE_ENABLED(dist_outputv)) {
          DTRACE_CHARBUF(port_str, 64);
          DTRACE_CHARBUF(remote_str, 64);
  
          erts_snprintf(port_str, sizeof(DTRACE_CHARBUF_NAME(port_str)),
                        "%T", prt->common.id);
          erts_snprintf(remote_str, sizeof(DTRACE_CHARBUF_NAME(remote_str)),
                        "%T", prt->dist_entry->sysname);
          DTRACE4(dist_outputv, erts_this_node_sysname, port_str,
                  remote_str, size);
      }
  #endif
      prt->caller = NIL;
      fpe_was_unmasked = erts_block_fpe();
      (*prt->drv_ptr->outputv)((ErlDrvData) prt->drv_data, &eiov);
      erts_unblock_fpe(fpe_was_unmasked);
  
      return size;
  }
  
  
  #if defined(ARCH_64)
  #define ERTS_PORT_REDS_MASK__ 0x003fffffffffffffL
  #elif defined(ARCH_32)
  #define ERTS_PORT_REDS_MASK__ 0x003fffff
  #else
  #  error "Ohh come on ... !?!"
  #endif
  
  #define ERTS_PORT_REDS_DIST_CMD_START 5
  #define ERTS_PORT_REDS_DIST_CMD_FINALIZE 3
  #define ERTS_PORT_REDS_DIST_CMD_EXIT 200
  #define ERTS_PORT_REDS_DIST_CMD_RESUMED 5
  #define ERTS_PORT_REDS_DIST_CMD_DATA(SZ) \
    ((SZ) < (1 << 10) \
     ? ((Sint) 1) \
     : ((((Sint) (SZ)) >> 10) & ((Sint) ERTS_PORT_REDS_MASK__)))
  
  int
  erts_dist_command(Port *prt, int reds_limit)
  {
      Sint reds = ERTS_PORT_REDS_DIST_CMD_START;
      Uint32 status;
      Uint32 flags;
      Sint obufsize = 0;
      ErtsDistOutputQueue oq, foq;
      DistEntry *dep = prt->dist_entry;
      Uint (*send)(Port *prt, ErtsDistOutputBuf *obuf);
      erts_aint32_t sched_flags;
      ErtsSchedulerData *esdp = erts_get_scheduler_data();
  
      ERTS_SMP_LC_ASSERT(erts_lc_is_port_locked(prt));
  
      erts_smp_refc_inc(&dep->refc, 1); /* Otherwise dist_entry might be
  				     removed if port command fails */
  
      erts_smp_atomic_set_mb(&dep->dist_cmd_scheduled, 0);
  
      erts_smp_de_rlock(dep);
      flags = dep->flags;
      status = dep->status;
      send = dep->send;
      erts_smp_de_runlock(dep);
  
      if (status & ERTS_DE_SFLG_EXITING) {
  	erts_deliver_port_exit(prt, prt->common.id, am_killed, 0, 1);
  	erts_deref_dist_entry(dep);
  	return reds + ERTS_PORT_REDS_DIST_CMD_EXIT;
      }
  
      ASSERT(send);
  
      /*
       * We need to remove both out queues from the
       * dist entry while passing it to port command;
       * otherwise, port command will free the buffers
       * in the queues on failure and we'll end up with
       * a mess.
       */
  
      erts_smp_mtx_lock(&dep->qlock);
      oq.first = dep->out_queue.first;
      oq.last = dep->out_queue.last;
      dep->out_queue.first = NULL;
      dep->out_queue.last = NULL;
      erts_smp_mtx_unlock(&dep->qlock);
  
      foq.first = dep->finalized_out_queue.first;
      foq.last = dep->finalized_out_queue.last;
      dep->finalized_out_queue.first = NULL;
      dep->finalized_out_queue.last = NULL;
  
      sched_flags = erts_smp_atomic32_read_nob(&prt->sched.flags);
  
      if (reds > reds_limit)
  	goto preempted;
  
      if (!(sched_flags & ERTS_PTS_FLG_BUSY_PORT) && foq.first) {
  	int preempt = 0;
  	do {
  	    Uint size;
  	    ErtsDistOutputBuf *fob;
  
  	    size = (*send)(prt, foq.first);
  	    esdp->io.out += (Uint64) size;
  #ifdef ERTS_RAW_DIST_MSG_DBG
  	    erts_fprintf(stderr, ">> ");
  	    bw(foq.first->extp, size);
  #endif
  	    reds += ERTS_PORT_REDS_DIST_CMD_DATA(size);
  	    fob = foq.first;
  	    obufsize += size_obuf(fob);
  	    foq.first = foq.first->next;
  	    free_dist_obuf(fob);
  	    sched_flags = erts_smp_atomic32_read_nob(&prt->sched.flags);
  	    preempt = reds > reds_limit || (sched_flags & ERTS_PTS_FLG_EXIT);
  	    if (sched_flags & ERTS_PTS_FLG_BUSY_PORT)
  		break;
  	} while (foq.first && !preempt);
  	if (!foq.first)
  	    foq.last = NULL;
  	if (preempt)
  	    goto preempted;
      }
  
      if (sched_flags & ERTS_PTS_FLG_BUSY_PORT) {
  	if (oq.first) {
  	    ErtsDistOutputBuf *ob;
  	    int preempt;
  	finalize_only:
  	    preempt = 0;
  	    ob = oq.first;
  	    ASSERT(ob);
  	    do {
  		ob->extp = erts_encode_ext_dist_header_finalize(ob->extp,
  								dep->cache,
  								flags);
  		if (!(flags & DFLAG_DIST_HDR_ATOM_CACHE))
  		    *--ob->extp = PASS_THROUGH; /* Old node; 'pass through'
  						   needed */
  		ASSERT(&ob->data[0] <= ob->extp && ob->extp < ob->ext_endp);
  		reds += ERTS_PORT_REDS_DIST_CMD_FINALIZE;
  		preempt = reds > reds_limit;
  		if (preempt)
  		    break;
  		ob = ob->next;
  	    } while (ob);
  	    /*
  	     * At least one buffer was finalized; if we got preempted,
  	     * ob points to the last buffer that we finalized.
  	     */
  	    if (foq.last)
  		foq.last->next = oq.first;
  	    else
  		foq.first = oq.first;
  	    if (!preempt) {
  		/* All buffers finalized */
  		foq.last = oq.last;
  		oq.first = oq.last = NULL;
  	    }
  	    else {
  		/* Not all buffers finalized; split oq. */
  		foq.last = ob;
  		oq.first = ob->next;
  		if (oq.first)
  		    ob->next = NULL;
  		else
  		    oq.last = NULL;
  	    }
  	    if (preempt)
  		goto preempted;
  	}
      }
      else {
  	int preempt = 0;
  	while (oq.first && !preempt) {
  	    ErtsDistOutputBuf *fob;
  	    Uint size;
  	    oq.first->extp
  		= erts_encode_ext_dist_header_finalize(oq.first->extp,
  						       dep->cache,
  						       flags);
  	    reds += ERTS_PORT_REDS_DIST_CMD_FINALIZE;
  	    if (!(flags & DFLAG_DIST_HDR_ATOM_CACHE))
  		*--oq.first->extp = PASS_THROUGH; /* Old node; 'pass through'
  						     needed */
  	    ASSERT(&oq.first->data[0] <= oq.first->extp
  		   && oq.first->extp < oq.first->ext_endp);
  	    size = (*send)(prt, oq.first);
  	    esdp->io.out += (Uint64) size;
  #ifdef ERTS_RAW_DIST_MSG_DBG
  	    erts_fprintf(stderr, ">> ");
  	    bw(oq.first->extp, size);
  #endif
  	    reds += ERTS_PORT_REDS_DIST_CMD_DATA(size);
  	    fob = oq.first;
  	    obufsize += size_obuf(fob);
  	    oq.first = oq.first->next;
  	    free_dist_obuf(fob);
  	    sched_flags = erts_smp_atomic32_read_nob(&prt->sched.flags);
  	    preempt = reds > reds_limit || (sched_flags & ERTS_PTS_FLG_EXIT);
  	    if ((sched_flags & ERTS_PTS_FLG_BUSY_PORT) && oq.first && !preempt)
  		goto finalize_only;
  	}
  
  	ASSERT(!oq.first || preempt);
  
  	/*
  	 * Preempt if not all buffers have been handled.
  	 */
  	if (preempt && oq.first)
  	    goto preempted;
  
  #ifdef DEBUG
  	oq.last = NULL;
  #endif
  	ASSERT(!oq.first);
  	ASSERT(!foq.first && !foq.last);
  
  	/*
  	 * Everything that was buffered when we started have now been
  	 * written to the port. If port isn't busy but dist entry is
  	 * and we havn't got too muched queued on dist entry, set
  	 * dist entry in a non-busy state and resume suspended
  	 * processes.
  	 */
  	erts_smp_mtx_lock(&dep->qlock);
  	ASSERT(dep->qsize >= obufsize);
  	dep->qsize -= obufsize;
  	obufsize = 0;
  	if (!(sched_flags & ERTS_PTS_FLG_BUSY_PORT)
  	    && (dep->qflgs & ERTS_DE_QFLG_BUSY)
  	    && dep->qsize < erts_dist_buf_busy_limit) {
  	    ErtsProcList *suspendees;
  	    int resumed;
  	    suspendees = get_suspended_on_de(dep, ERTS_DE_QFLG_BUSY);
  	    erts_smp_mtx_unlock(&dep->qlock);
  
  	    resumed = erts_resume_processes(suspendees);
  	    reds += resumed*ERTS_PORT_REDS_DIST_CMD_RESUMED;
  	}
  	else
  	    erts_smp_mtx_unlock(&dep->qlock);
      }
  
      ASSERT(!oq.first && !oq.last);
  
   done:
  
      if (obufsize != 0) {
  	ASSERT(obufsize > 0);
  	erts_smp_mtx_lock(&dep->qlock);
  	ASSERT(dep->qsize >= obufsize);
  	dep->qsize -= obufsize;
  	erts_smp_mtx_unlock(&dep->qlock);
      }
  
      ASSERT(foq.first || !foq.last);
      ASSERT(!foq.first || foq.last);
      ASSERT(!dep->finalized_out_queue.first);
      ASSERT(!dep->finalized_out_queue.last);
  
      if (foq.first) {
  	dep->finalized_out_queue.first = foq.first;
  	dep->finalized_out_queue.last = foq.last;
      }
  
       /* Avoid wrapping reduction counter... */
      if (reds > INT_MAX/2)
  	reds = INT_MAX/2;
  
      erts_deref_dist_entry(dep);
  
      return reds;
  
   preempted:
      /*
       * Here we assume that state has been read
       * since last call to driver.
       */
  
      ASSERT(oq.first || !oq.last);
      ASSERT(!oq.first || oq.last);
  
      if (sched_flags & ERTS_PTS_FLG_EXIT) {
  	/*
  	 * Port died during port command; clean up 'oq'
  	 * and 'foq'. Things buffered in dist entry after
  	 * we begun processing the queues have already been
  	 * cleaned up when port terminated.
  	 */
  
  	if (oq.first)
  	    oq.last->next = foq.first;
  	else
  	    oq.first = foq.first;
  
  	while (oq.first) {
  	    ErtsDistOutputBuf *fob = oq.first;
  	    oq.first = oq.first->next;
  	    obufsize += size_obuf(fob);
  	    free_dist_obuf(fob);
  	}
  
  	foq.first = NULL;
  	foq.last = NULL;
  
  #ifdef DEBUG
  	erts_smp_mtx_lock(&dep->qlock);
  	ASSERT(dep->qsize == obufsize);
  	erts_smp_mtx_unlock(&dep->qlock);
  #endif
      }
      else {
  	if (oq.first) {
  	    /*
  	     * Unhandle buffers need to be put back first
  	     * in out_queue.
  	     */
  	    erts_smp_mtx_lock(&dep->qlock);
  	    dep->qsize -= obufsize;
  	    obufsize = 0;
  	    oq.last->next = dep->out_queue.first;
  	    dep->out_queue.first = oq.first;
  	    if (!dep->out_queue.last)
  		dep->out_queue.last = oq.last;
  	    erts_smp_mtx_unlock(&dep->qlock);
  	}
  
  	erts_schedule_dist_command(prt, NULL);
      }
      goto done;
  }
  
  void
  erts_dist_port_not_busy(Port *prt)
  {
  #ifdef USE_VM_PROBES
      if (DTRACE_ENABLED(dist_port_not_busy)) {
          DTRACE_CHARBUF(port_str, 64);
          DTRACE_CHARBUF(remote_str, 64);
  
          erts_snprintf(port_str, sizeof(DTRACE_CHARBUF_NAME(port_str)),
                        "%T", prt->common.id);
          erts_snprintf(remote_str, sizeof(DTRACE_CHARBUF_NAME(remote_str)),
                        "%T", prt->dist_entry->sysname);
          DTRACE3(dist_port_not_busy, erts_this_node_sysname,
                  port_str, remote_str);
      }
  #endif
      erts_schedule_dist_command(prt, NULL);
  }
  
  void
  erts_kill_dist_connection(DistEntry *dep, Uint32 connection_id)
  {
      erts_smp_de_rwlock(dep);
      if (is_internal_port(dep->cid)
  	&& connection_id == dep->connection_id
  	&& !(dep->status & ERTS_DE_SFLG_EXITING)) {
  
  	dep->status |= ERTS_DE_SFLG_EXITING;
  
  	erts_smp_mtx_lock(&dep->qlock);
  	ASSERT(!(dep->qflgs & ERTS_DE_QFLG_EXIT));
  	dep->qflgs |= ERTS_DE_QFLG_EXIT;
  	erts_smp_mtx_unlock(&dep->qlock);
  
  	erts_schedule_dist_command(NULL, dep);
      }
      erts_smp_de_rwunlock(dep);
  }
  
  struct print_to_data {
      fmtfn_t to;
      void *arg;
  };
  
  static void doit_print_monitor_info(ErtsMonitor *mon, void *vptdp)
  {
      fmtfn_t to = ((struct print_to_data *) vptdp)->to;
      void *arg = ((struct print_to_data *) vptdp)->arg;
      Process *rp;
      ErtsMonitor *rmon;
      rp = erts_proc_lookup(mon->u.pid);
      if (!rp || (rmon = erts_lookup_monitor(ERTS_P_MONITORS(rp), mon->ref)) == NULL) {
  	erts_print(to, arg, "Warning, stray monitor for: %T\n", mon->u.pid);
      } else if (mon->type == MON_ORIGIN) {
  	/* Local pid is being monitored */
  	erts_print(to, arg, "Remotely monitored by: %T %T\n",
  		   mon->u.pid, rmon->u.pid);
      } else {
  	erts_print(to, arg, "Remote monitoring: %T ", mon->u.pid);
  	if (is_not_atom(rmon->u.pid))
  	    erts_print(to, arg, "%T\n", rmon->u.pid);
  	else
  	    erts_print(to, arg, "{%T, %T}\n",
  		       rmon->name,
  		       rmon->u.pid); /* which in this case is the 
  				      remote system name... */
      }
  }    
  
  static void print_monitor_info(fmtfn_t to, void *arg, ErtsMonitor *mon)
  {
      struct print_to_data ptd = {to, arg};
      erts_doforall_monitors(mon,&doit_print_monitor_info,&ptd);
  }
  
  typedef struct {
      struct print_to_data *ptdp;
      Eterm from;
  } PrintLinkContext;
  
  static void doit_print_link_info2(ErtsLink *lnk, void *vpplc)
  {
      PrintLinkContext *pplc = (PrintLinkContext *) vpplc;
      erts_print(pplc->ptdp->to, pplc->ptdp->arg, "Remote link: %T %T\n",
  	       pplc->from, lnk->pid);
  }
  
  static void doit_print_link_info(ErtsLink *lnk, void *vptdp)
  {
      if (is_internal_pid(lnk->pid) && erts_proc_lookup(lnk->pid)) {
  	PrintLinkContext plc = {(struct print_to_data *) vptdp, lnk->pid};
  	erts_doforall_links(ERTS_LINK_ROOT(lnk), &doit_print_link_info2, &plc);
      } 
  }
  
  static void print_link_info(fmtfn_t to, void *arg, ErtsLink *lnk)
  {
      struct print_to_data ptd = {to, arg};
      erts_doforall_links(lnk, &doit_print_link_info, (void *) &ptd);
  }
  
  typedef struct {
      struct print_to_data ptd;
      Eterm sysname;
  } PrintNodeLinkContext;
      
  
  static void doit_print_nodelink_info(ErtsLink *lnk, void *vpcontext)
  {
      PrintNodeLinkContext *pcontext = vpcontext;
  
      if (is_internal_pid(lnk->pid) && erts_proc_lookup(lnk->pid))
  	erts_print(pcontext->ptd.to, pcontext->ptd.arg,
  		   "Remote monitoring: %T %T\n", lnk->pid, pcontext->sysname);
  }
  
  static void print_nodelink_info(fmtfn_t to, void *arg, ErtsLink *lnk, Eterm sysname)
  {
      PrintNodeLinkContext context = {{to, arg}, sysname};
      erts_doforall_links(lnk, &doit_print_nodelink_info, &context);
  }
  
  
  static int
  info_dist_entry(fmtfn_t to, void *arg, DistEntry *dep, int visible, int connected)
  {
  
    if (visible && connected) {
        erts_print(to, arg, "=visible_node:");
    } else if (connected) {
        erts_print(to, arg, "=hidden_node:");
    } else {
        erts_print(to, arg, "=not_connected:");
    }
    erts_print(to, arg, "%d\n", dist_entry_channel_no(dep));
  
    if(connected && is_nil(dep->cid)) {
      erts_print(to, arg,
  	       "Error: Not connected node still registered as connected:%T\n",
  	       dep->sysname);
      return 0;
    }
  
    if(!connected && is_not_nil(dep->cid)) {
      erts_print(to, arg,
  	       "Error: Connected node not registered as connected:%T\n",
  	       dep->sysname);
      return 0;
    }
  
    erts_print(to, arg, "Name: %T", dep->sysname);
  #ifdef DEBUG
    erts_print(to, arg, " (refc=%d)", erts_smp_refc_read(&dep->refc, 0));
  #endif
    erts_print(to, arg, "\n");
    if (!connected && is_nil(dep->cid)) {
      if (dep->nlinks) {
        erts_print(to, arg, "Error: Got links to not connected node:%T\n",
  		 dep->sysname);
      }
      return 0;
    }
  
    erts_print(to, arg, "Controller: %T\n", dep->cid, to);
  
    erts_print_node_info(to, arg, dep->sysname, NULL, NULL);
    print_monitor_info(to, arg, dep->monitors);
    print_link_info(to, arg, dep->nlinks);
    print_nodelink_info(to, arg, dep->node_links, dep->sysname);
  
    return 0;
      
  }
  int distribution_info(fmtfn_t to, void *arg)	/* Called by break handler */
  {
      DistEntry *dep;
  
      erts_print(to, arg, "=node:%T\n", erts_this_dist_entry->sysname);
   
      if (erts_this_node->sysname == am_Noname) {
  	erts_print(to, arg, "=no_distribution\n");
  	return(0);
      }
  
  #if 0
      if (!erts_visible_dist_entries && !erts_hidden_dist_entries) 
        erts_print(to, arg, "Alive but not holding any connections \n");
  #endif
  
      for(dep = erts_visible_dist_entries; dep; dep = dep->next) {
        info_dist_entry(to, arg, dep, 1, 1);
      }
  
      for(dep = erts_hidden_dist_entries; dep; dep = dep->next) {
        info_dist_entry(to, arg, dep, 0, 1);
      }
  
      for (dep = erts_not_connected_dist_entries; dep; dep = dep->next) {
          if (dep != erts_this_dist_entry) {
              info_dist_entry(to, arg, dep, 0, 0);
          }
      }
  
      return(0);
  }
  
  /****************************************************************************
    DISTRIBUTION BIFS:
  
              setnode/2     -- start distribution
              setnode/3     -- set node controller
  
              node/1        -- return objects node name
              node/0        -- return this node name
              nodes/0       -- return a list of all (non hidden) nodes
              is_alive      -- return true if distribution is running else false
  	    monitor_node  -- turn on/off node monitoring
  
              node controller only:
              dist_exit/3       -- send exit signals from remote to local process
              dist_link/2       -- link a remote process to a local
              dist_unlink/2     -- unlink a remote from a local
  ****************************************************************************/
  
  
  
  /**********************************************************************
   ** Set the node name of current node fail if node already is set.
   ** setnode(name@host, Creation)
   ** loads functions pointer to trap_functions from module erlang.
   **    erlang:dsend/2
   **    erlang:dlink/1
   **    erlang:dunlink/1
   **    erlang:dmonitor_node/3
   **    erlang:dgroup_leader/2
   **    erlang:dexit/2
   **  -- are these needed ?
   **    dexit/1
   ***********************************************************************/
  
  BIF_RETTYPE setnode_2(BIF_ALIST_2)
  {
      Process *net_kernel;
      Uint creation;
  
      /* valid creation ? */
      if(!term_to_Uint(BIF_ARG_2, &creation))
  	goto error;
      if(creation > 3)
  	goto error;
  
      /* valid node name ? */
      if (!is_node_name_atom(BIF_ARG_1))
  	goto error;
  
      if (BIF_ARG_1 == am_Noname) /* cant use this name !! */
  	goto error;
      if (erts_is_alive)     /* must not be alive! */
  	goto error;
  
      /* Check that all trap functions are defined !! */
      if (dsend2_trap->addressv[0] == NULL ||
  	dsend3_trap->addressv[0] == NULL ||
  	/*	dsend_nosuspend_trap->address == NULL ||*/
  	dlink_trap->addressv[0] == NULL ||
  	dunlink_trap->addressv[0] == NULL ||
  	dmonitor_node_trap->addressv[0] == NULL ||
  	dgroup_leader_trap->addressv[0] == NULL ||
  	dmonitor_p_trap->addressv[0] == NULL ||
  	dexit_trap->addressv[0] == NULL) {
  	goto error;
      }
  
      net_kernel = erts_whereis_process(BIF_P, ERTS_PROC_LOCK_MAIN,
  				      am_net_kernel, ERTS_PROC_LOCK_MAIN, 0);
      if (!net_kernel)
  	goto error;
  
      /* By setting F_DISTRIBUTION on net_kernel,
       * do_net_exist will be called when net_kernel is terminated !! */
      net_kernel->flags |= F_DISTRIBUTION;
  
      if (net_kernel != BIF_P)
  	erts_smp_proc_unlock(net_kernel, ERTS_PROC_LOCK_MAIN);
  
  #ifdef DEBUG
      erts_smp_rwmtx_rlock(&erts_dist_table_rwmtx);
      ASSERT(!erts_visible_dist_entries && !erts_hidden_dist_entries);
      erts_smp_rwmtx_runlock(&erts_dist_table_rwmtx);
  #endif
  
      erts_smp_proc_unlock(BIF_P, ERTS_PROC_LOCK_MAIN);
      erts_smp_thr_progress_block();
      inc_no_nodes();
      erts_set_this_node(BIF_ARG_1, (Uint32) creation);
      erts_is_alive = 1;
      send_nodes_mon_msgs(NULL, am_nodeup, BIF_ARG_1, am_visible, NIL);
      erts_smp_thr_progress_unblock();
      erts_smp_proc_lock(BIF_P, ERTS_PROC_LOCK_MAIN);
  
      BIF_RET(am_true);
  
   error:
      BIF_ERROR(BIF_P, BADARG);
  }
  
  /**********************************************************************
   ** Allocate a dist entry, set node name install the connection handler
   ** setnode_3({name@host, Creation}, Cid, {Type, Version, Initial, IC, OC})
   ** Type = flag field, where the flags are specified in dist.h
   ** Version = distribution version, >= 1
   ** IC = in_cookie (ignored)
   ** OC = out_cookie (ignored)
   **
   ** Note that in distribution protocols above 1, the Initial parameter
   ** is always NIL and the cookies are always the atom '', cookies are not
   ** sent in the distribution messages but are only used in 
   ** the handshake.
   **
   ***********************************************************************/
  
  BIF_RETTYPE setnode_3(BIF_ALIST_3)
  {
      BIF_RETTYPE ret;
      Uint flags;
      unsigned long version;
      Eterm ic, oc;
      Eterm *tp;
      DistEntry *dep = NULL;
      Port *pp = NULL;
  
      /* Prepare for success */
      ERTS_BIF_PREP_RET(ret, am_true);
  
      /*
       * Check and pick out arguments
       */
  
      if (!is_node_name_atom(BIF_ARG_1) ||
  	is_not_internal_port(BIF_ARG_2) ||
  	(erts_this_node->sysname == am_Noname)) {
  	goto badarg;
      }
  
      if (!is_tuple(BIF_ARG_3))
  	goto badarg;
      tp = tuple_val(BIF_ARG_3);
      if (*tp++ != make_arityval(4))
  	goto badarg;
      if (!is_small(*tp))
  	goto badarg;
      flags = unsigned_val(*tp++);
      if (!is_small(*tp) || (version = unsigned_val(*tp)) == 0)
  	goto badarg;
      ic = *(++tp);
      oc = *(++tp);
      if (!is_atom(ic) || !is_atom(oc))
  	goto badarg;
  
      /* DFLAG_EXTENDED_REFERENCES is compulsory from R9 and forward */
      if (!(DFLAG_EXTENDED_REFERENCES & flags)) {
  	erts_dsprintf_buf_t *dsbufp = erts_create_logger_dsbuf();
  	erts_dsprintf(dsbufp, "%T", BIF_P->common.id);
  	if (BIF_P->common.u.alive.reg)
  	    erts_dsprintf(dsbufp, " (%T)", BIF_P->common.u.alive.reg->name);
  	erts_dsprintf(dsbufp,
  		      " attempted to enable connection to node %T "
  		      "which is not able to handle extended references.\n",
  		      BIF_ARG_1);
  	erts_send_error_to_logger(BIF_P->group_leader, dsbufp);
  	goto badarg;
      }
  
      /*
       * Arguments seem to be in order.
       */
  
      /* get dist_entry */
      dep = erts_find_or_insert_dist_entry(BIF_ARG_1);
      if (dep == erts_this_dist_entry)
  	goto badarg;
      else if (!dep)
  	goto system_limit; /* Should never happen!!! */
  
      pp = erts_id2port_sflgs(BIF_ARG_2,
  			    BIF_P,
  			    ERTS_PROC_LOCK_MAIN,
  			    ERTS_PORT_SFLGS_INVALID_LOOKUP);
      erts_smp_de_rwlock(dep);
  
      if (!pp || (erts_atomic32_read_nob(&pp->state)
  		& ERTS_PORT_SFLG_EXITING))
  	goto badarg;
  
      if ((pp->drv_ptr->flags & ERL_DRV_FLAG_SOFT_BUSY) == 0)
  	goto badarg;
  
      if (dep->cid == BIF_ARG_2 && pp->dist_entry == dep)
  	goto done; /* Already set */
  
      if (dep->status & ERTS_DE_SFLG_EXITING) {
  	/* Suspend on dist entry waiting for the exit to finish */
  	ErtsProcList *plp = erts_proclist_create(BIF_P);
  	plp->next = NULL;
  	erts_suspend(BIF_P, ERTS_PROC_LOCK_MAIN, NULL);
  	erts_smp_mtx_lock(&dep->qlock);
  	erts_proclist_store_last(&dep->suspended, plp);
  	erts_smp_mtx_unlock(&dep->qlock);
  	goto yield;
      }
  
      ASSERT(!(dep->status & ERTS_DE_SFLG_EXITING));
  
      if (pp->dist_entry || is_not_nil(dep->cid))
  	goto badarg;
  
      erts_atomic32_read_bor_nob(&pp->state, ERTS_PORT_SFLG_DISTRIBUTION);
  
      /*
       * Dist-ports do not use the "busy port message queue" functionality, but
       * instead use "busy dist entry" functionality.
       */
      {
  	ErlDrvSizeT disable = ERL_DRV_BUSY_MSGQ_DISABLED;
  	erl_drv_busy_msgq_limits(ERTS_Port2ErlDrvPort(pp), &disable, NULL);
      }
  
      pp->dist_entry = dep;
  
      dep->version = version;
      dep->creation = 0;
  
      ASSERT(pp->drv_ptr->outputv || pp->drv_ptr->output);
  
  #if 1
      dep->send = (pp->drv_ptr->outputv
  		 ? dist_port_commandv
  		 : dist_port_command);
  #else
      dep->send = dist_port_command;
  #endif
      ASSERT(dep->send);
  
  #ifdef DEBUG
      erts_smp_mtx_lock(&dep->qlock);
      ASSERT(dep->qsize == 0);
      erts_smp_mtx_unlock(&dep->qlock);
  #endif
  
      erts_set_dist_entry_connected(dep, BIF_ARG_2, flags);
  
      if (flags & DFLAG_DIST_HDR_ATOM_CACHE)
  	create_cache(dep);
  
      erts_smp_de_rwunlock(dep);
      dep = NULL; /* inc of refc transferred to port (dist_entry field) */
  
      inc_no_nodes();
  
      send_nodes_mon_msgs(BIF_P,
  			am_nodeup,
  			BIF_ARG_1,
  			flags & DFLAG_PUBLISHED ? am_visible : am_hidden,
  			NIL);
   done:
  
      if (dep && dep != erts_this_dist_entry) {
  	erts_smp_de_rwunlock(dep);
  	erts_deref_dist_entry(dep);
      }
  
      if (pp)
  	erts_port_release(pp);
  
      return ret;
  
   yield:
      ERTS_BIF_PREP_YIELD3(ret, bif_export[BIF_setnode_3], BIF_P,
  			 BIF_ARG_1, BIF_ARG_2, BIF_ARG_3);
      goto done;
  
   badarg:
      ERTS_BIF_PREP_ERROR(ret, BIF_P, BADARG);
      goto done;
  
   system_limit:
      ERTS_BIF_PREP_ERROR(ret, BIF_P, SYSTEM_LIMIT);
      goto done;
  }
  
  
  /**********************************************************************/
  /* dist_exit(Local, Term, Remote) -> Bool */
  
  BIF_RETTYPE dist_exit_3(BIF_ALIST_3)
  {
      Eterm local;
      Eterm remote;
      DistEntry *rdep;
  
      local = BIF_ARG_1;
      remote = BIF_ARG_3;
  
      /* Check that remote is a remote process */
      if (is_not_external_pid(remote))
  	goto error;
  
      rdep = external_dist_entry(remote);
      
      if(rdep == erts_this_dist_entry)
  	goto error;
  
      /* Check that local is local */
      if (is_internal_pid(local)) {
  	Process *lp;
  	ErtsProcLocks lp_locks;
  	if (BIF_P->common.id == local) {
  	    lp_locks = ERTS_PROC_LOCKS_ALL;
  	    lp = BIF_P;
  	    erts_smp_proc_lock(BIF_P, ERTS_PROC_LOCKS_ALL_MINOR);
  	}
  	else {
  	    lp_locks = ERTS_PROC_LOCKS_XSIG_SEND;
  	    lp = erts_pid2proc(BIF_P, ERTS_PROC_LOCK_MAIN,
  			       local, lp_locks);
  	    if (!lp) {
  		BIF_RET(am_true); /* ignore */
  	    }
  	}
  	
  	(void) erts_send_exit_signal(BIF_P,
  				     remote,
  				     lp,
  				     &lp_locks,
  				     BIF_ARG_2,
  				     NIL,
  				     NULL,
  				     0);
  #ifdef ERTS_SMP
  	if (lp == BIF_P)
  	    lp_locks &= ~ERTS_PROC_LOCK_MAIN;
  #endif
  	erts_smp_proc_unlock(lp, lp_locks);
  	if (lp == BIF_P) {
  	    erts_aint32_t state = erts_smp_atomic32_read_acqb(&BIF_P->state);
  	    /*
  	     * We may have exited current process and may have to take action.
  	     */
  	    if (state & (ERTS_PSFLG_EXITING|ERTS_PSFLG_PENDING_EXIT)) {
  #ifdef ERTS_SMP
  		if (state & ERTS_PSFLG_PENDING_EXIT)
  		    erts_handle_pending_exit(BIF_P, ERTS_PROC_LOCK_MAIN);
  #endif
  		ERTS_BIF_EXITED(BIF_P);
  	    }
  	}
      }
      else if (is_external_pid(local)
  	     && external_dist_entry(local) == erts_this_dist_entry) {
  	BIF_RET(am_true); /* ignore */
      }
      else
  	goto error;
      BIF_RET(am_true);
  
   error:
      BIF_ERROR(BIF_P, BADARG);
  }
  
  /**********************************************************************/
  /* node(Object) -> Node */
  
  BIF_RETTYPE node_1(BIF_ALIST_1)
  { 
      if (is_not_node_container(BIF_ARG_1))
        BIF_ERROR(BIF_P, BADARG);
      BIF_RET(node_container_node_name(BIF_ARG_1));
  }
  
  /**********************************************************************/
  /* node() -> Node */
  
  BIF_RETTYPE node_0(BIF_ALIST_0)
  {
      BIF_RET(erts_this_dist_entry->sysname);
  }
  
  
  /**********************************************************************/
  /* nodes() -> [ Node ] */
  
  #if 0 /* Done in erlang.erl instead. */
  BIF_RETTYPE nodes_0(BIF_ALIST_0)
  {
    return nodes_1(BIF_P, am_visible);
  }
  #endif
  
  
  BIF_RETTYPE nodes_1(BIF_ALIST_1)
  {
      Eterm result;
      int length;
      Eterm* hp;
      int not_connected = 0;
      int visible = 0;
      int hidden = 0;
      int this = 0;
      DeclareTmpHeap(buf,2,BIF_P); /* For one cons-cell */
      DistEntry *dep;
      Eterm arg_list = BIF_ARG_1;
  #ifdef DEBUG
      Eterm* endp;
  #endif
  
      UseTmpHeap(2,BIF_P);
  
      if (is_atom(BIF_ARG_1))
        arg_list = CONS(buf, BIF_ARG_1, NIL);
  
      while (is_list(arg_list)) {
        switch(CAR(list_val(arg_list))) {
        case am_visible:   visible = 1;                                 break;
        case am_hidden:    hidden = 1;                                  break;
        case am_known:     visible = hidden = not_connected = this = 1; break;
        case am_this:      this = 1;                                    break;
        case am_connected: visible = hidden = 1;                        break;
        default:           goto error;                                  break;
        }
        arg_list = CDR(list_val(arg_list));
      }
  
      if (is_not_nil(arg_list)) {
  	goto error;
      }
  
      length = 0;
  
      erts_smp_rwmtx_rlock(&erts_dist_table_rwmtx);
  
      ASSERT(erts_no_of_not_connected_dist_entries > 0);
      ASSERT(erts_no_of_hidden_dist_entries >= 0);
      ASSERT(erts_no_of_visible_dist_entries >= 0);
      if(not_connected)
        length += (erts_no_of_not_connected_dist_entries - 1);
      if(hidden)
        length += erts_no_of_hidden_dist_entries;
      if(visible)
        length += erts_no_of_visible_dist_entries;
      if(this)
        length++;
  
      result = NIL;
  
      if (length == 0) {
  	erts_smp_rwmtx_runlock(&erts_dist_table_rwmtx);
  	goto done;
      }
  
      hp = HAlloc(BIF_P, 2*length);
  
  #ifdef DEBUG
      endp = hp + length*2;
  #endif
      if(not_connected)
        for(dep = erts_not_connected_dist_entries; dep; dep = dep->next) {
            if (dep != erts_this_dist_entry) {
              result = CONS(hp, dep->sysname, result);
              hp += 2;
            }
        }
      if(hidden)
        for(dep = erts_hidden_dist_entries; dep; dep = dep->next) {
  	result = CONS(hp, dep->sysname, result);
  	hp += 2;
        }
      if(visible)
        for(dep = erts_visible_dist_entries; dep; dep = dep->next) {
  	result = CONS(hp, dep->sysname, result);
  	hp += 2;
        }
      if(this) {
  	result = CONS(hp, erts_this_dist_entry->sysname, result);
  	hp += 2;
      }
      ASSERT(endp == hp);
      erts_smp_rwmtx_runlock(&erts_dist_table_rwmtx);
  
  done:
      UnUseTmpHeap(2,BIF_P);
      BIF_RET(result);
  
  error:
      UnUseTmpHeap(2,BIF_P);
      BIF_ERROR(BIF_P,BADARG);
  }
  
  /**********************************************************************/
  /* is_alive() -> Bool */
  
  BIF_RETTYPE is_alive_0(BIF_ALIST_0)
  {
      Eterm res = erts_is_alive ? am_true : am_false;
      BIF_RET(res);
  }
  
  /**********************************************************************/
  /* erlang:monitor_node(Node, Bool, Options) -> Bool */
  
  static BIF_RETTYPE
  monitor_node(Process* p, Eterm Node, Eterm Bool, Eterm Options)
  {
      DistEntry *dep;
      ErtsLink *lnk;
      Eterm l;
  
      for (l = Options; l != NIL && is_list(l); l = CDR(list_val(l))) {
  	Eterm t = CAR(list_val(l));
  	/* allow_passive_connect the only available option right now */
  	if (t != am_allow_passive_connect) {
  	    BIF_ERROR(p, BADARG);
  	}
      }
      if (l != NIL) {
  	BIF_ERROR(p, BADARG);
      }
  
      if (is_not_atom(Node) ||
  	((Bool != am_true) && (Bool != am_false)) ||
  	((erts_this_node->sysname == am_Noname)
  	 && (Node != erts_this_node->sysname))) {
  	BIF_ERROR(p, BADARG);
      }
      dep = erts_sysname_to_connected_dist_entry(Node);
      if (!dep) {
      do_trap:
  	BIF_TRAP3(dmonitor_node_trap, p, Node, Bool, Options);
      }
      if (dep == erts_this_dist_entry)
  	goto done;
  
      erts_smp_proc_lock(p, ERTS_PROC_LOCK_LINK);
      erts_smp_de_rlock(dep);
      if (ERTS_DE_IS_NOT_CONNECTED(dep)) {
  	erts_smp_proc_unlock(p, ERTS_PROC_LOCK_LINK);
  	erts_smp_de_runlock(dep);
  	goto do_trap;
      }
      erts_smp_de_links_lock(dep);
      erts_smp_de_runlock(dep);
  
      if (Bool == am_true) {
  	ASSERT(dep->cid != NIL);
  	lnk = erts_add_or_lookup_link(&(dep->node_links), LINK_NODE, 
  				      p->common.id);
  	++ERTS_LINK_REFC(lnk);
  	lnk = erts_add_or_lookup_link(&ERTS_P_LINKS(p), LINK_NODE, Node);
  	++ERTS_LINK_REFC(lnk);
      }
      else  {
  	lnk = erts_lookup_link(dep->node_links, p->common.id);
  	if (lnk != NULL) {
  	    if ((--ERTS_LINK_REFC(lnk)) == 0) {
  		erts_destroy_link(erts_remove_link(&(dep->node_links), 
  						   p->common.id));
  	    }
  	}
  	lnk = erts_lookup_link(ERTS_P_LINKS(p), Node);
  	if (lnk != NULL) {
  	    if ((--ERTS_LINK_REFC(lnk)) == 0) {
  		erts_destroy_link(erts_remove_link(&ERTS_P_LINKS(p),
  						   Node));
  	    }
  	}
      }
  
      erts_smp_de_links_unlock(dep);
      erts_smp_proc_unlock(p, ERTS_PROC_LOCK_LINK);
  
   done:
      erts_deref_dist_entry(dep);
      BIF_RET(am_true);
  }
  
  BIF_RETTYPE monitor_node_3(BIF_ALIST_3)
  {
      BIF_RET(monitor_node(BIF_P, BIF_ARG_1, BIF_ARG_2, BIF_ARG_3));
  }
  
  
  /* monitor_node(Node, Bool) -> Bool */
  
  BIF_RETTYPE monitor_node_2(BIF_ALIST_2)
  {
      BIF_RET(monitor_node(BIF_P, BIF_ARG_1, BIF_ARG_2, NIL));
  }
  
  BIF_RETTYPE net_kernel_dflag_unicode_io_1(BIF_ALIST_1)
  {
      DistEntry *de;
      Uint32 f;
      if (is_not_pid(BIF_ARG_1)) {
  	BIF_ERROR(BIF_P,BADARG);
      }
      de = pid_dist_entry(BIF_ARG_1);
      ASSERT(de != NULL);
      if (de == erts_this_dist_entry) {
  	BIF_RET(am_true);
      }
      erts_smp_de_rlock(de);
      f = de->flags;
      erts_smp_de_runlock(de);
      BIF_RET(((f & DFLAG_UNICODE_IO) ? am_true : am_false));
  }
      
  /*
   * The major part of the implementation of net_kernel:monitor_nodes/[1,2]
   * follows.
   *
   * Currently net_kernel:monitor_nodes/[1,2] calls process_flag/2 which in
   * turn calls erts_monitor_nodes(). If the process_flag() call fails (with
   * badarg), the code in net_kernel determines what type of error to return.
   * This in order to simplify the task of being backward compatible.
   */
  
  #define ERTS_NODES_MON_OPT_TYPE_VISIBLE		(((Uint16) 1) << 0)
  #define ERTS_NODES_MON_OPT_TYPE_HIDDEN		(((Uint16) 1) << 1)
  #define ERTS_NODES_MON_OPT_DOWN_REASON		(((Uint16) 1) << 2)
  
  #define ERTS_NODES_MON_OPT_TYPES \
    (ERTS_NODES_MON_OPT_TYPE_VISIBLE|ERTS_NODES_MON_OPT_TYPE_HIDDEN)
  
  typedef struct ErtsNodesMonitor_ ErtsNodesMonitor;
  struct ErtsNodesMonitor_ {
      ErtsNodesMonitor *prev;
      ErtsNodesMonitor *next;
      Process *proc;
      Uint16 opts;
      Uint16 no;
  };
  
  static erts_smp_mtx_t nodes_monitors_mtx;
  static ErtsNodesMonitor *nodes_monitors;
  static ErtsNodesMonitor *nodes_monitors_end;
  
  /*
   * Nodes monitors are stored in a double linked list. 'nodes_monitors'
   * points to the beginning of the list and 'nodes_monitors_end' points
   * to the end of the list.
   *
   * There might be more than one entry per process in the list. If so,
   * they are located in sequence. The 'nodes_monitors' field of the
   * process struct refers to the first element in the sequence
   * corresponding to the process in question.
   */
  
  static void
  init_nodes_monitors(void)
  {
      erts_smp_mtx_init(&nodes_monitors_mtx, "nodes_monitors");
      nodes_monitors = NULL;
      nodes_monitors_end = NULL;
  }
  
  static ERTS_INLINE Uint
  nodes_mon_msg_sz(ErtsNodesMonitor *nmp, Eterm what, Eterm reason)
  {
      Uint sz;
      if (!nmp->opts) {
  	sz = 3;
      }
      else {
  	sz = 0;
  
  	if (nmp->opts & ERTS_NODES_MON_OPT_TYPES)
  	    sz += 2 + 3;
  
  	if (what == am_nodedown
  	    && (nmp->opts & ERTS_NODES_MON_OPT_DOWN_REASON)) {
  	    if (is_not_immed(reason))
  		sz += size_object(reason);
  	    sz += 2 + 3;
  	}
  
  	sz += 4;
      }
      return sz;
  }
  
  static ERTS_INLINE void
  send_nodes_mon_msg(Process *rp,
  		   ErtsProcLocks *rp_locksp,
  		   ErtsNodesMonitor *nmp,
  		   Eterm node,
  		   Eterm what,
  		   Eterm type,
  		   Eterm reason,
  		   Uint sz)
  {
      Eterm msg;
      Eterm *hp;
      ErtsMessage *mp;
      ErlOffHeap *ohp;
  #ifdef DEBUG
      Eterm *hend;
  #endif
  
      mp = erts_alloc_message_heap(rp, rp_locksp, sz, &hp, &ohp);
  #ifdef DEBUG
      hend = hp + sz;
  #endif
  
      if (!nmp->opts) {
  	msg = TUPLE2(hp, what, node);
  #ifdef DEBUG
  	hp += 3;
  #endif
      }
      else {
  	Eterm tup;
  	Eterm info = NIL;
  
  	if (nmp->opts & (ERTS_NODES_MON_OPT_TYPE_VISIBLE
  			 | ERTS_NODES_MON_OPT_TYPE_HIDDEN)) {
  
  	    tup = TUPLE2(hp, am_node_type, type);
  	    hp += 3;
  	    info = CONS(hp, tup, info);
  	    hp += 2;
  	}
  
  	if (what == am_nodedown
  	    && (nmp->opts & ERTS_NODES_MON_OPT_DOWN_REASON)) {
  	    Eterm rsn_cpy;
  	    
  	    if (is_immed(reason))
  		rsn_cpy = reason;
  	    else {
  		Eterm rsn_sz = size_object(reason);
  		rsn_cpy = copy_struct(reason, rsn_sz, &hp, ohp);
  	    }
  
  	    tup = TUPLE2(hp, am_nodedown_reason, rsn_cpy);
  	    hp += 3;
  	    info = CONS(hp, tup, info);
  	    hp += 2;
  	}
  
  	msg = TUPLE3(hp, what, node, info);
  #ifdef DEBUG
  	hp += 4;
  #endif
      }
  
      ASSERT(hend == hp);
      erts_queue_message(rp, *rp_locksp, mp, msg, am_system);
  }
  
  static void
  send_nodes_mon_msgs(Process *c_p, Eterm what, Eterm node, Eterm type, Eterm reason)
  {
      ErtsNodesMonitor *nmp;
      ErtsProcLocks rp_locks = 0; /* Init to shut up false warning */
      Process *rp = NULL;
  
      ASSERT(is_immed(what));
      ASSERT(is_immed(node));
      ASSERT(is_immed(type));
  #ifdef USE_VM_PROBES
      if (DTRACE_ENABLED(dist_monitor)) {
          DTRACE_CHARBUF(what_str, 12);
          DTRACE_CHARBUF(node_str, 64);
          DTRACE_CHARBUF(type_str, 12);
          DTRACE_CHARBUF(reason_str, 64);
  
          erts_snprintf(what_str, sizeof(DTRACE_CHARBUF_NAME(what_str)), "%T", what);
          erts_snprintf(node_str, sizeof(DTRACE_CHARBUF_NAME(node_str)), "%T", node);
          erts_snprintf(type_str, sizeof(DTRACE_CHARBUF_NAME(type_str)), "%T", type);
          erts_snprintf(reason_str, sizeof(DTRACE_CHARBUF_NAME(reason_str)), "%T", reason);
          DTRACE5(dist_monitor, erts_this_node_sysname,
                  what_str, node_str, type_str, reason_str);
      }
  #endif
  
      ERTS_SMP_LC_ASSERT(!c_p
  		       || (erts_proc_lc_my_proc_locks(c_p)
  			   == ERTS_PROC_LOCK_MAIN));
      erts_smp_mtx_lock(&nodes_monitors_mtx);
  
      for (nmp = nodes_monitors; nmp; nmp = nmp->next) {
  	int i;
  	Uint16 no;
  	Uint sz;
  
  	ASSERT(nmp->proc != NULL);
  
  	if (!nmp->opts) {
  	    if (type != am_visible)
  		continue;
  	}
  	else {
  	    switch (type) {
  	    case am_hidden:
  		if (!(nmp->opts & ERTS_NODES_MON_OPT_TYPE_HIDDEN))
  		    continue;
  		break;
  	    case am_visible:
  		if ((nmp->opts & ERTS_NODES_MON_OPT_TYPES)
  		    && !(nmp->opts & ERTS_NODES_MON_OPT_TYPE_VISIBLE))
  		    continue;
  		break;
  	    default:
  		erts_exit(ERTS_ABORT_EXIT, "Bad node type found\n");
  	    }
  	}
  
  	if (rp != nmp->proc) {
  	    if (rp) {
  		if (rp == c_p)
  		    rp_locks &= ~ERTS_PROC_LOCK_MAIN;
  		erts_smp_proc_unlock(rp, rp_locks);
  	    }
  
  	    rp = nmp->proc;
  	    rp_locks = 0;
  	    if (rp == c_p)
  		rp_locks |= ERTS_PROC_LOCK_MAIN;
  	}
  
  	ASSERT(rp);
  
  	sz = nodes_mon_msg_sz(nmp, what, reason);
  
  	for (i = 0, no = nmp->no; i < no; i++)
  	    send_nodes_mon_msg(rp,
  			       &rp_locks,
  			       nmp,
  			       node,
  			       what,
  			       type,
  			       reason,
  			       sz);
      }
  
      if (rp) {
  	if (rp == c_p)
  	    rp_locks &= ~ERTS_PROC_LOCK_MAIN;
  	erts_smp_proc_unlock(rp, rp_locks);
      }
  
      erts_smp_mtx_unlock(&nodes_monitors_mtx);
  }
  
  static Eterm
  insert_nodes_monitor(Process *c_p, Uint32 opts)
  {
      Uint16 no = 1;
      Eterm res = am_false;
      ErtsNodesMonitor *xnmp, *nmp;
  
      ERTS_SMP_LC_ASSERT(erts_smp_lc_mtx_is_locked(&nodes_monitors_mtx));
      ERTS_SMP_LC_ASSERT(erts_proc_lc_my_proc_locks(c_p) & ERTS_PROC_LOCK_MAIN);
  
      xnmp = c_p->nodes_monitors;
      if (xnmp) {
  	ASSERT(!xnmp->prev || xnmp->prev->proc != c_p);
  
  	while (1) {
  	    ASSERT(xnmp->proc == c_p);
  	    if (xnmp->opts == opts)
  		break;
  	    if (!xnmp->next || xnmp->next->proc != c_p)
  		break;
  	    xnmp = xnmp->next;
  	}
  	ASSERT(xnmp);
  	ASSERT(xnmp->proc == c_p);
  	ASSERT(xnmp->opts == opts
  	       || !xnmp->next
  	       || xnmp->next->proc != c_p);
  
  	if (xnmp->opts != opts)
  	    goto alloc_new;
  	else {
  	    res = am_true;
  	    no = xnmp->no++;
  	    if (!xnmp->no) {
  		/*
  		 * 'no' wrapped; transfer all prevous monitors to new
  		 * element (which will be the next element in the list)
  		 * and set this to one...
  		 */
  		xnmp->no = 1;
  		goto alloc_new;
  	    }
  	}
      }
      else {
      alloc_new:
  	nmp = erts_alloc(ERTS_ALC_T_NODES_MON, sizeof(ErtsNodesMonitor));
  	nmp->proc = c_p;
  	nmp->opts = opts;
  	nmp->no = no;
  
  	if (xnmp) {
  	    ASSERT(nodes_monitors);
  	    ASSERT(c_p->nodes_monitors);
  	    nmp->next = xnmp->next;
  	    nmp->prev = xnmp;
  	    xnmp->next = nmp;
  	    if (nmp->next) {
  		ASSERT(nodes_monitors_end != xnmp);
  		ASSERT(nmp->next->prev == xnmp);
  		nmp->next->prev = nmp;
  	    }
  	    else {
  		ASSERT(nodes_monitors_end == xnmp);
  		nodes_monitors_end = nmp;
  	    }
  	}
  	else {
  	    ASSERT(!c_p->nodes_monitors);
  	    c_p->nodes_monitors = nmp;
  	    nmp->next = NULL;
  	    nmp->prev = nodes_monitors_end;
  	    if (nodes_monitors_end) {
  		ASSERT(nodes_monitors);
  		nodes_monitors_end->next = nmp;
  	    }
  	    else {
  		ASSERT(!nodes_monitors);
  		nodes_monitors = nmp;
  	    }
  	    nodes_monitors_end = nmp;
  	}
      }
      return res;
  }
  
  static Eterm
  remove_nodes_monitors(Process *c_p, Uint32 opts, int all)
  {
      Eterm res = am_false;
      ErtsNodesMonitor *nmp;
  
      ERTS_SMP_LC_ASSERT(erts_smp_lc_mtx_is_locked(&nodes_monitors_mtx));
      ERTS_SMP_LC_ASSERT(erts_proc_lc_my_proc_locks(c_p) & ERTS_PROC_LOCK_MAIN);
  
      nmp = c_p->nodes_monitors;
      ASSERT(!nmp || !nmp->prev || nmp->prev->proc != c_p);
  
      while (nmp && nmp->proc == c_p) {
  	if (!all && nmp->opts != opts)
  	    nmp = nmp->next;
  	else { /* if (all || nmp->opts == opts) */
  	    ErtsNodesMonitor *free_nmp;
  	    res = am_true;
  	    if (nmp->prev) {
  		ASSERT(nodes_monitors != nmp);
  		nmp->prev->next = nmp->next;
  	    }
  	    else {
  		ASSERT(nodes_monitors == nmp);
  		nodes_monitors = nmp->next;
  	    }
  	    if (nmp->next) {
  		ASSERT(nodes_monitors_end != nmp);
  		nmp->next->prev = nmp->prev;
  	    }
  	    else {
  		ASSERT(nodes_monitors_end == nmp);
  		nodes_monitors_end = nmp->prev;
  	    }
  	    free_nmp = nmp;
  	    nmp = nmp->next;
  	    if (c_p->nodes_monitors == free_nmp)
  		c_p->nodes_monitors = nmp && nmp->proc == c_p ? nmp : NULL;
  	    erts_free(ERTS_ALC_T_NODES_MON, free_nmp);
  	}
      }
      
      ASSERT(!all || !c_p->nodes_monitors);
      return res;
  }
  
  void
  erts_delete_nodes_monitors(Process *c_p, ErtsProcLocks locks)
  {
  #if defined(ERTS_ENABLE_LOCK_CHECK) && defined(ERTS_SMP)
      if (c_p) {
  	ErtsProcLocks might_unlock = locks & ~ERTS_PROC_LOCK_MAIN;
  	if (might_unlock)
  	    erts_proc_lc_might_unlock(c_p, might_unlock);
      }
  #endif
      if (erts_smp_mtx_trylock(&nodes_monitors_mtx) == EBUSY) {
  	ErtsProcLocks unlock_locks = locks & ~ERTS_PROC_LOCK_MAIN;
  	if (c_p && unlock_locks)
  	    erts_smp_proc_unlock(c_p, unlock_locks);
  	erts_smp_mtx_lock(&nodes_monitors_mtx);
  	if (c_p && unlock_locks)
  	    erts_smp_proc_lock(c_p, unlock_locks);
      }
      remove_nodes_monitors(c_p, 0, 1);
      erts_smp_mtx_unlock(&nodes_monitors_mtx);
  }
  
  Eterm
  erts_monitor_nodes(Process *c_p, Eterm on, Eterm olist)
  {
      Eterm res;
      Eterm opts_list = olist;
      Uint16 opts = (Uint16) 0;
  
      ASSERT(c_p);
      ERTS_SMP_LC_ASSERT(erts_proc_lc_my_proc_locks(c_p) == ERTS_PROC_LOCK_MAIN);
  
      if (on != am_true && on != am_false)
  	return THE_NON_VALUE;
  
      if (is_not_nil(opts_list)) {
  	int all = 0, visible = 0, hidden = 0;
  
  	while (is_list(opts_list)) {
  	    Eterm *cp = list_val(opts_list);
  	    Eterm opt = CAR(cp);
  	    opts_list = CDR(cp);
  	    if (opt == am_nodedown_reason)
  		opts |= ERTS_NODES_MON_OPT_DOWN_REASON;
  	    else if (is_tuple(opt)) {
  		Eterm* tp = tuple_val(opt);
  		if (arityval(tp[0]) != 2)
  		    return THE_NON_VALUE;
  		switch (tp[1]) {
  		case am_node_type:
  		    switch (tp[2]) {
  		    case am_visible:
  			if (hidden || all)
  			    return THE_NON_VALUE;
  			opts |= ERTS_NODES_MON_OPT_TYPE_VISIBLE;
  			visible = 1;
  			break;
  		    case am_hidden:
  			if (visible || all)
  			    return THE_NON_VALUE;
  			opts |= ERTS_NODES_MON_OPT_TYPE_HIDDEN;
  			hidden = 1;
  			break;
  		    case am_all:
  			if (visible || hidden)
  			    return THE_NON_VALUE;
  			opts |= ERTS_NODES_MON_OPT_TYPES;
  			all = 1;
  			break;
  		    default:
  			return THE_NON_VALUE;
  		    }
  		    break;
  		default:
  		    return THE_NON_VALUE;
  		}
  	    }
  	    else {
  		return THE_NON_VALUE;
  	    }
  	}
  
  	if (is_not_nil(opts_list))
  	    return THE_NON_VALUE;
      }
  
      erts_smp_mtx_lock(&nodes_monitors_mtx);
  
      if (on == am_true)
  	res = insert_nodes_monitor(c_p, opts);
      else
  	res = remove_nodes_monitors(c_p, opts, 0);
  
      erts_smp_mtx_unlock(&nodes_monitors_mtx);
  
      return res;
  }
  
  /*
   * Note, this function is only used for debuging.
   */
  
  Eterm
  erts_processes_monitoring_nodes(Process *c_p)
  {
      ErtsNodesMonitor *nmp;
      Eterm res;
      Eterm *hp;
      Eterm **hpp;
      Uint sz;
      Uint *szp;
  #ifdef DEBUG
      Eterm *hend;
  #endif
  
      ASSERT(c_p);
      ERTS_SMP_LC_ASSERT(erts_proc_lc_my_proc_locks(c_p) == ERTS_PROC_LOCK_MAIN);
      erts_smp_mtx_lock(&nodes_monitors_mtx);
  
      sz = 0;
      szp = &sz;
      hpp = NULL;
  
   bld_result:
      res = NIL;
  
      for (nmp = nodes_monitors_end; nmp; nmp = nmp->prev) {
  	Uint16 i;
  	for (i = 0; i < nmp->no; i++) {
  	    Eterm olist = NIL;
  	    if (nmp->opts & ERTS_NODES_MON_OPT_TYPES) {
  		Eterm type;
  		switch (nmp->opts & ERTS_NODES_MON_OPT_TYPES) {
  		case ERTS_NODES_MON_OPT_TYPES:        type = am_all;     break;
  		case ERTS_NODES_MON_OPT_TYPE_VISIBLE: type = am_visible; break;
  		case ERTS_NODES_MON_OPT_TYPE_HIDDEN:  type = am_hidden;  break;
  		default: erts_exit(ERTS_ABORT_EXIT, "Bad node type found\n");
  		}
  		olist = erts_bld_cons(hpp, szp, 
  				      erts_bld_tuple(hpp, szp, 2,
  						     am_node_type,
  						     type),
  				      olist);
  	    }
  	    if (nmp->opts & ERTS_NODES_MON_OPT_DOWN_REASON)
  		olist = erts_bld_cons(hpp, szp, am_nodedown_reason, olist);
  	    res = erts_bld_cons(hpp, szp,
  				erts_bld_tuple(hpp, szp, 2,
  					       nmp->proc->common.id,
  					       olist),
  				res);
  	}
      }
  
      if (!hpp) {
  	hp = HAlloc(c_p, sz);
  #ifdef DEBUG
  	hend = hp + sz;
  #endif
  	hpp = &hp;
  	szp = NULL;
  	goto bld_result;
      }
  
      ASSERT(hp == hend);
  
      erts_smp_mtx_unlock(&nodes_monitors_mtx);
  
      return res;
  }
  