Initial revision

1 files changed, 810 insertions, 0 deletions

diff --git a/trans/new-fifo.c b/trans/new-fifo.c
new file mode 100644
index 00000000..44dd5afc
--- /dev/null
+++ b/trans/new-fifo.c
@@ -0,0 +1,810 @@
+/* A translator for fifos
+
+   Copyright (C) 1995, 1996 Free Software Foundation, Inc.
+
+   Written by Miles Bader <miles@gnu.ai.mit.edu>
+
+   This program is free software; you can redistribute it and/or
+   modify it under the terms of the GNU General Public License as
+   published by the Free Software Foundation; either version 2, or (at
+   your option) any later version.
+
+   This program is distributed in the hope that it will be useful, but
+   WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
+
+#include <stdio.h>
+#include <errno.h>
+#include <argp.h>
+#include <unistd.h>
+#include <error.h>
+#include <string.h>
+#include <fcntl.h>
+#include <assert.h>
+
+#include <cthreads.h>
+#include <hurd.h>
+#include <argz.h>
+#include <hurd/fshelp.h>
+#include <hurd/ports.h>
+#include <hurd/trivfs.h>
+#include <hurd/fsys.h>
+#include <hurd/pipe.h>
+#include <hurd/paths.h>
+
+#define DEFAULT_SERVER _SERVERS "fifo";
+
+struct port_bucket *port_bucket;
+struct port_class *fifo_port_class, *server_port_class, *fsys_port_class;
+
+/* ---------------------------------------------------------------- */
+
+static const struct argp_option options[] =
+{
+  {"multiple-readers", 'r', 0,     0, "Allow multiple simultaneous readers"},
+  {"noblock",          'n', 0,     0, "Don't block on open"},
+  {"dgram",            'd', 0,     0, "Reflect write record boundaries"},
+  {"server",	       's', 0,     0, "Operate in server mode"},
+  {"standalone",       'S', 0,     0, "Don't attempt to use a fifo server"},
+  {"use-server",       'U', "NAME",0, "Attempt use server NAME"},
+  {0,0}
+};
+
+/* Per translator variables.  */
+struct fifo_trans
+{
+  /* True if this not a real translator, but instead a translator server,
+     which responds to requests to create translators.  */
+  int server;
+
+  /* True if opens for writing should hang until there's a reader.  */
+  int wait_for_reader;
+  /* True if opens for reading should hang until there's a writer.  */
+  int wait_for_writer;
+  /* True if opens for read should hang until there are no other readers.  */
+  int one_reader;
+
+  /* If non-null, the name of a fifo server to do the translation in our
+     stead.  */
+  char *use_server;
+
+  /* The translator from which this was initialized.  */
+  struct fifo_trans *parent;
+
+  /* What kinds of pipes we use.  */
+  struct pipe_class *fifo_pipe_class;
+
+  /* The current fifo that new opens will see, or NULL if there is none.  */
+  struct pipe *active_fifo;
+  /* Lock this when changing ACTIVE_FIFO.  */
+  struct mutex active_fifo_lock;
+  /* Signal this when ACTIVE_FIFO may have changed.  */
+  struct condition active_fifo_changed;
+};
+
+/* Return a new FIFO_TRANS in TRANS, initializing it from FROM if it's
+   non-null, where possible.  */
+static void
+fifo_trans_create (struct fifo_trans *from, struct fifo_trans **trans)
+{
+  struct fifo_trans *new = malloc (sizeof (struct fifo_trans));
+
+  new->server = 0;
+  mutex_init (&new->active_fifo_lock);
+  condition_init (&new->active_fifo_changed);
+
+  new->parent = from;
+
+  if (from)
+    /* Inherit things that can be inherited.  */
+    {
+      new->wait_for_reader = from->wait_for_reader;
+      new->wait_for_writer = from->wait_for_writer;
+      new->one_reader = from->one_reader;
+      new->use_server = from->use_server;
+      new->fifo_pipe_class = from->fifo_pipe_class;
+    }
+  else
+    /* Otherwise just use default values.  */
+    {
+      new->wait_for_reader = 1;
+      new->wait_for_writer = 1;
+      new->one_reader = 1;
+      new->use_server = DEFAULT_SERVER;
+      new->fifo_pipe_class = stream_pipe_class;
+    }
+
+  *trans = new;
+}
+
+static void
+fifo_trans_free (struct fifo_trans *trans)
+{
+  free (trans);
+}
+
+static error_t
+fifo_trans_start (struct fifo_trans *trans, mach_port_t requestor)
+{
+  struct trivfs_control *control;
+  struct port_class *class =
+    (trans->server ? server_port_class : fifo_port_class);
+  error_t
+    err = trivfs_startup (requestor, 0,
+			  fsys_port_class, port_bucket, class, port_bucket,
+			  &control);
+  if (!err)
+    control->hook = trans;
+  return err;
+}
+
+/* Parse our options.  SERVER is true if we are a fifo server providing
+   service for others (in which case we don't print error messages).  The
+   results of the parse are put into TRANS.  */
+static error_t
+fifo_trans_parse_args (struct fifo_trans *trans, int argc, char **argv,
+		       int print_errs)
+{
+  error_t parse_opt (int key, char *arg, struct argp_state *state)
+    {
+      switch (key)
+	{
+	case 'r': trans->one_reader = 0; break;
+	case 'n': trans->wait_for_reader = trans->wait_for_writer = 0; break;
+	case 'd': trans->fifo_pipe_class = seqpack_pipe_class;
+	case 's': trans->server = 1; break;
+	case 'U': trans->use_server = arg; break;
+	case 'S': trans->use_server = 0; break;
+	default:  return EINVAL;
+	}
+      return 0;
+    }
+  struct argp argp = {options, parse_opt};
+  return argp_parse (&argp, argc, argv, print_errs ? 0 : ARGP_SILENT, 0);
+}
+
+/* ---------------------------------------------------------------- */
+
+struct port_class *trivfs_protid_portclasses[1];
+struct port_class *trivfs_cntl_portclasses[1];
+int trivfs_protid_nportclasses = 1;
+int trivfs_cntl_nportclasses = 1;
+
+void
+main (int argc, char **argv)
+{
+  error_t err;
+  mach_port_t bootstrap;
+  struct fifo_trans *trans;
+  /* Clean up a fsys control node.  */
+  void clean_fsys (void *vfsys)
+    {
+      struct trivfs_control *fsys = vfsys;
+      if (fsys->hook)
+	fifo_trans_free (fsys->hook);
+      trivfs_clean_cntl (fsys);
+    }
+
+  fifo_trans_create (0, &trans);
+
+  if (fifo_trans_parse_args (trans, argc, argv, 1) != 0)
+    exit (1);
+
+  task_get_bootstrap_port (mach_task_self (), &bootstrap);
+  if (bootstrap == MACH_PORT_NULL)
+    error(1, 0, "must be started as a translator");
+
+  if (!trans->server && trans->use_server)
+    /* Attempt to contact a fifo server to do our work for us.  */
+    {
+      err = fshelp_delegate_translation (trans->use_server, bootstrap, argv);
+      if (!err)
+	exit (0);
+    }
+
+  port_bucket = ports_create_bucket ();
+  fifo_port_class =  ports_create_class (trivfs_clean_protid, 0);
+  server_port_class =  ports_create_class (trivfs_clean_protid, 0);
+  fsys_port_class = ports_create_class (clean_fsys, 0);
+
+  trivfs_protid_portclasses[0] = fifo_port_class;
+  trivfs_protid_portclasses[1] = server_port_class;
+  trivfs_cntl_portclasses[0] = fsys_port_class;
+
+  /* Reply to our parent */
+  fifo_trans_start (trans, bootstrap);
+
+  /* Launch. */
+  do
+    {
+      ports_enable_class (fifo_port_class);
+      ports_manage_port_operations_multithread (port_bucket,
+						trivfs_demuxer,
+						30*1000, 5*60*1000, 0, 0);
+    }
+  while (ports_count_class (fifo_port_class) > 0);
+
+  exit (0);
+}
+
+/* ---------------------------------------------------------------- */
+
+static error_t
+fifo_trans_open (struct fifo_trans *trans, int flags, void **hook)
+{
+  error_t err = 0;
+
+  if (flags & (O_READ | O_WRITE))
+    {
+      mutex_lock (&trans->active_fifo_lock);
+
+/* Wait until the active fifo has changed so that CONDITION is true.  */
+#define WAIT(condition, noblock_err)					     \
+  while (!err && !(condition)) 						     \
+    if (flags & O_NONBLOCK) 						     \
+      {			 						     \
+        err = noblock_err; 						     \
+        break;		 						     \
+      }			 						     \
+    else if (hurd_condition_wait (&trans->active_fifo_changed,		     \
+				  &trans->active_fifo_lock))		     \
+      err = EINTR;
+
+      if (flags & O_READ)
+	/* When opening for read, what we do depends on what mode this server
+	   is running in.  The default (if ONE_READER is set) is to only
+	   allow one reader at a time, with additional opens for read
+	   blocking here until the old reader goes away; otherwise, we allow
+	   multiple readers.  If WAIT_FOR_WRITER is true, then once we've
+	   created a fifo, we also block until someone opens it for writing;
+	   otherwise, the first read will block until someone writes
+	   something.  */
+	{
+	  if (trans->one_reader)
+	    /* Wait until there isn't any active fifo, so we can make one. */
+	    WAIT (!trans->active_fifo || !trans->active_fifo->readers,
+		  EWOULDBLOCK);
+	  if (!err && trans->active_fifo == NULL)
+	    /* No other readers, and indeed, no fifo; make one.  */
+	    err = pipe_create (trans->fifo_pipe_class, &trans->active_fifo);
+	  if (!err)
+	    {
+	      pipe_add_reader (trans->active_fifo);
+	      condition_broadcast (&trans->active_fifo_changed);
+	      /* We'll unlock ACTIVE_FIFO_LOCK below; the writer code won't
+		 make us block because we've ensured that there's a reader
+		 for it.  */
+
+	      if (trans->wait_for_writer)
+		/* Wait until there's a writer.  */
+		{
+		  WAIT (trans->active_fifo->writers, 0);
+		  if (err)
+		    /* Back out the new pipe creation.  */
+		    {
+		      pipe_remove_reader (trans->active_fifo);
+		      trans->active_fifo = NULL;
+		      condition_broadcast (&trans->active_fifo_changed);
+		    }
+		}
+	      else
+		/* Otherwise prevent an immediate eof.  */
+		trans->active_fifo->flags &= ~PIPE_BROKEN;
+	    }
+	}
+
+      if (!err && (flags & O_WRITE))
+	/* Open the trans->active_fifo for writing.  If WAIT_FOR_READER is
+	   true, then we block until there's someone to read what we wrote,
+	   otherwise, if there's no fifo, we create one, which we just write
+	   into and leave it for someone to read later.  */
+	{
+	  if (trans->wait_for_reader)
+	    /* Wait until there's a fifo to write to.  */
+	    WAIT (trans->active_fifo && trans->active_fifo->readers, 0);
+	  if (!err && trans->active_fifo == NULL)
+	    /* No other readers, and indeed, no fifo; make one.  */
+	    {
+	      err = pipe_create (trans->fifo_pipe_class, &trans->active_fifo);
+	      if (!err)
+		trans->active_fifo->flags &= ~PIPE_BROKEN;
+	    }
+	  if (!err)
+	    {
+	      pipe_add_writer (trans->active_fifo);
+	      condition_broadcast (&trans->active_fifo_changed);
+	    }
+	}
+
+      *hook = trans->active_fifo;
+    }
+
+  mutex_unlock (&trans->active_fifo_lock);
+
+  return err;
+}
+
+static void
+fifo_trans_close (struct fifo_trans *trans, struct trivfs_peropen *po)
+{
+  int was_active, going_away = 0;
+  int flags = po->openmodes;
+  struct pipe *pipe = po->hook;
+
+  if (!pipe)
+    return;
+
+  mutex_lock (&trans->active_fifo_lock);
+  was_active = (trans->active_fifo == pipe);
+
+  if (was_active)
+    /* We're the last reader; when we're gone there is no more joy.  */
+    going_away = ((flags & O_READ) && pipe->readers == 1);
+  else
+    /* Let others have their fun.  */
+    mutex_unlock (&trans->active_fifo_lock);
+
+  if (flags & O_READ)
+    pipe_remove_reader (pipe);
+  if (flags & O_WRITE)
+    pipe_remove_writer (pipe);
+  /* At this point, PIPE may be gone, so we can't look at it again.  */
+
+  if (was_active)
+    {
+      if (going_away)
+	trans->active_fifo = NULL;
+      condition_broadcast (&trans->active_fifo_changed);
+      mutex_unlock (&trans->active_fifo_lock);
+    }
+}
+
+static error_t
+open_hook (struct trivfs_peropen *po)
+{
+  struct fifo_trans *trans = po->cntl->hook;
+
+  if (! trans->server)
+    /* We're opening a normal fifo node.  */
+    return fifo_trans_open (trans, po->openmodes, &po->hook);
+  else if (po->openmodes & (O_READ|O_WRITE|O_APPEND))
+    return EPERM;
+  else
+    /* We're a fifo server serving a new fifo.  */
+    return 0;
+}
+
+static void
+close_hook (struct trivfs_peropen *po)
+{
+  struct fifo_trans *trans = po->cntl->hook;
+
+  if (! trans->server)
+    /* We're closing a normal fifo node.  */
+    fifo_trans_close (trans, po);
+}
+
+/* Trivfs hooks  */
+
+int trivfs_fstype = FSTYPE_MISC;
+int trivfs_fsid = 0;
+
+int trivfs_support_read = 1;
+int trivfs_support_write = 1;
+int trivfs_support_exec = 0;
+
+int trivfs_allow_open = O_READ | O_WRITE;
+
+error_t (*trivfs_peropen_create_hook) (struct trivfs_peropen *) = open_hook;
+void (*trivfs_peropen_destroy_hook) (struct trivfs_peropen *) = close_hook;
+
+void
+trivfs_modify_stat (struct trivfs_protid *cred, struct stat *st)
+{
+  struct fifo_trans *trans = cred->po->cntl->hook;
+  if (! trans->server)
+    /* A fifo node */
+    {
+      struct pipe *pipe = cred->po->hook;
+
+      st->st_mode &= ~S_IFMT;
+      st->st_mode |= S_IFIFO;
+
+      if (pipe)
+	{
+	  mutex_lock (&pipe->lock);
+	  st->st_size = pipe_readable (pipe, 1);
+	  st->st_blocks = st->st_size >> 9;
+	  mutex_unlock (&pipe->lock);
+	}
+      else
+	st->st_size = st->st_blocks = 0;
+
+      /* As we try to be clever with large transfers, ask for them. */
+      st->st_blksize = vm_page_size * 16;
+    }
+}
+
+error_t
+trivfs_goaway (struct trivfs_control *fsys, int flags)
+{
+  error_t err;
+  int num_opens;
+  int force = flags & FSYS_GOAWAY_FORCE;
+  int unlink = flags & FSYS_GOAWAY_UNLINK;
+  struct fifo_trans *trans = fsys->hook;
+
+  err = ports_inhibit_port_rpcs (fsys);
+  if (err == EINTR || (err && !force))
+    return err;
+
+  num_opens = ports_count_class (fsys->protid_class);
+  if (num_opens > 0 && !force && !unlink)
+    /* Still some opens, and we're not being forced to go away, so don't.*/
+    {
+      ports_enable_class (fsys->protid_class);
+      ports_resume_port_rpcs (fsys);
+      return EBUSY;
+    }
+
+  /* Kill the control connection.  */
+  mach_port_deallocate (mach_task_self (), fsys->underlying);
+  fsys->underlying = MACH_PORT_NULL;
+  ports_destroy_right (fsys);
+
+  if (force)
+    /* Kill opens.  */
+    {
+      error_t maybe_trash_protid (void *vcred)
+	{
+	  struct trivfs_protid *cred = vcred;
+	  if (cred->po->cntl == fsys)
+	    {
+	      ports_destroy_right (cred);
+	      ports_interrupt_rpcs (cred);
+	    }
+	  return 0;
+	}
+      ports_bucket_iterate (((struct port_info *)fsys)->bucket,
+			    maybe_trash_protid);
+    }
+
+  if (! trans->parent)
+    /* The root translator, go away, bye bye.  */
+    exit (0);
+
+  /* Let things continue; what should die will.  */
+  ports_enable_class (fsys->protid_class);
+  ports_resume_port_rpcs (fsys);
+
+  return 0;
+}
+
+/* ---------------------------------------------------------------- */
+
+/* Return objects mapping the data underlying this memory object.  If
+   the object can be read then memobjrd will be provided; if the
+   object can be written then memobjwr will be provided.  For objects
+   where read data and write data are the same, these objects will be
+   equal, otherwise they will be disjoint.  Servers are permitted to
+   implement io_map but not io_map_cntl.  Some objects do not provide
+   mapping; they will set none of the ports and return an error.  Such
+   objects can still be accessed by io_read and io_write.  */
+error_t
+trivfs_S_io_map(struct trivfs_protid *cred,
+		memory_object_t *rdobj,
+		mach_msg_type_name_t *rdtype,
+		memory_object_t *wrobj,
+		mach_msg_type_name_t *wrtype)
+{
+  return EINVAL;
+}
+
+/* ---------------------------------------------------------------- */
+
+/* Read data from an IO object.  If offset if -1, read from the object
+   maintained file pointer.  If the object is not seekable, offset is
+   ignored.  The amount desired to be read is in AMT.  */
+error_t
+trivfs_S_io_read (struct trivfs_protid *cred,
+		  mach_port_t reply, mach_msg_type_name_t reply_type,
+		  char **data, size_t *data_len,
+		  off_t offs, size_t amount)
+{
+  error_t err;
+
+  if (!cred)
+    err = EOPNOTSUPP;
+  else if (!(cred->po->openmodes & O_READ))
+    err = EBADF;
+  else
+    {
+      struct pipe *pipe = cred->po->hook;
+      assert (pipe);
+      mutex_lock (&pipe->lock);
+      err = pipe_read (pipe, cred->po->openmodes & O_NONBLOCK, NULL,
+		       data, data_len, amount);
+      mutex_unlock (&pipe->lock);
+    }
+
+  return err;
+}
+
+/* ---------------------------------------------------------------- */
+
+/* Tell how much data can be read from the object without blocking for
+   a "long time" (this should be the same meaning of "long time" used
+   by the nonblocking flag.  */
+error_t
+trivfs_S_io_readable (struct trivfs_protid *cred,
+		      mach_port_t reply, mach_msg_type_name_t reply_type,
+		      size_t *amount)
+{
+  error_t err;
+
+  if (!cred)
+    err = EOPNOTSUPP;
+  else if (!(cred->po->openmodes & O_READ))
+    err = EBADF;
+  else
+    {
+      struct pipe *pipe = cred->po->hook;
+      assert (pipe);
+      mutex_lock (&pipe->lock);
+      *amount = pipe_readable (pipe, 1);
+      mutex_unlock (&pipe->lock);
+      err = 0;
+    }
+
+  return err;
+}
+
+/* ---------------------------------------------------------------- */
+
+/* Change current read/write offset */
+error_t
+trivfs_S_io_seek (struct trivfs_protid *cred,
+		  mach_port_t reply, mach_msg_type_name_t reply_type,
+		  off_t offset, int whence, off_t *new_offset)
+{
+  if (!cred)
+    return EOPNOTSUPP;
+  return ESPIPE;
+}
+
+/* ---------------------------------------------------------------- */
+
+/* SELECT_TYPE is the bitwise OR of SELECT_READ, SELECT_WRITE, and SELECT_URG.
+   Block until one of the indicated types of i/o can be done "quickly", and
+   return the types that are then available.  ID_TAG is returned as passed; it
+   is just for the convenience of the user in matching up reply messages with
+   specific requests sent.  */
+error_t
+trivfs_S_io_select (struct trivfs_protid *cred,
+		    mach_port_t reply, mach_msg_type_name_t reply_type,
+		    int *select_type, int *tag)
+{
+  struct pipe *pipe;
+  error_t err = 0;
+  int ready = 0;
+
+  if (!cred)
+    return EOPNOTSUPP;
+
+  pipe = cred->po->hook;
+
+  if (*select_type & SELECT_READ)
+    if (cred->po->openmodes & O_READ)
+      {
+	mutex_lock (&pipe->lock);
+	if (pipe_wait_readable (pipe, 1, 1) != EWOULDBLOCK)
+	  ready |= SELECT_READ; /* Data immediately readable (or error). */
+	mutex_unlock (&pipe->lock);
+      }
+    else
+      ready |= SELECT_READ;	/* Error immediately available...  */
+
+  if (*select_type & SELECT_WRITE)
+    if (cred->po->openmodes & O_WRITE)
+      {
+	mutex_lock (&pipe->lock);
+	if (pipe_wait_writable (pipe, 1) != EWOULDBLOCK)
+	  ready |= SELECT_WRITE; /* Data immediately writable (or error). */
+	mutex_unlock (&pipe->lock);
+      }
+    else
+      ready |= SELECT_WRITE;	/* Error immediately available...  */
+
+  if (ready)
+    *select_type = ready;
+  else
+    /* Wait for something to change.  */
+    {
+      ports_interrupt_self_on_port_death (cred, reply);
+      err = pipe_pair_select (pipe, pipe, select_type, 1);
+    }
+
+  return err;
+}
+
+/* ---------------------------------------------------------------- */
+
+/* Write data to an IO object.  If offset is -1, write at the object
+   maintained file pointer.  If the object is not seekable, offset is
+   ignored.  The amount successfully written is returned in amount.  A
+   given user should not have more than one outstanding io_write on an
+   object at a time; servers implement congestion control by delaying
+   responses to io_write.  Servers may drop data (returning ENOBUFS)
+   if they recevie more than one write when not prepared for it.  */
+error_t
+trivfs_S_io_write (struct trivfs_protid *cred,
+		   mach_port_t reply, mach_msg_type_name_t reply_type,
+		   char *data, size_t data_len,
+		   off_t offs, size_t *amount)
+{
+  error_t err;
+
+  if (!cred)
+    err = EOPNOTSUPP;
+  else if (!(cred->po->openmodes & O_WRITE))
+    err = EBADF;
+  else
+    {
+      struct pipe *pipe = cred->po->hook;
+      mutex_lock (&pipe->lock);
+      err = pipe_write (pipe, cred->po->openmodes & O_NONBLOCK, NULL,
+			data, data_len, amount);
+      mutex_unlock (&pipe->lock);
+    }
+
+  return err;
+}
+
+/* ---------------------------------------------------------------- */
+
+/* Truncate file.  */
+error_t
+trivfs_S_file_set_size (struct trivfs_protid *cred,
+			mach_port_t reply, mach_msg_type_name_t reply_type,
+			off_t size)
+{
+  return size == 0 ? 0 : EINVAL;
+}
+
+/* ---------------------------------------------------------------- */
+/* These four routines modify the O_APPEND, O_ASYNC, O_FSYNC, and
+   O_NONBLOCK bits for the IO object. In addition, io_get_openmodes
+   will tell you which of O_READ, O_WRITE, and O_EXEC the object can
+   be used for.  The O_ASYNC bit affects icky async I/O; good async 
+   I/O is done through io_async which is orthogonal to these calls. */
+
+error_t
+trivfs_S_io_get_openmodes (struct trivfs_protid *cred,
+			   mach_port_t reply, mach_msg_type_name_t reply_type,
+			   int *bits)
+{
+  if (!cred)
+    return EOPNOTSUPP;
+  else
+    {
+      *bits = cred->po->openmodes;
+      return 0;
+    }
+}
+
+error_t
+trivfs_S_io_set_all_openmodes(struct trivfs_protid *cred,
+			      mach_port_t reply,
+			      mach_msg_type_name_t reply_type,
+			      int mode)
+{
+  if (!cred)
+    return EOPNOTSUPP;
+  else
+    return 0;
+}
+
+error_t
+trivfs_S_io_set_some_openmodes (struct trivfs_protid *cred,
+				mach_port_t reply,
+				mach_msg_type_name_t reply_type,
+				int bits)
+{
+  if (!cred)
+    return EOPNOTSUPP;
+  else
+    return 0;
+}
+
+error_t
+trivfs_S_io_clear_some_openmodes (struct trivfs_protid *cred,
+				  mach_port_t reply,
+				  mach_msg_type_name_t reply_type,
+				  int bits)
+{
+  if (!cred)
+    return EOPNOTSUPP;
+  else
+    return 0;
+}
+
+/* ---------------------------------------------------------------- */
+/* Get/set the owner of the IO object.  For terminals, this affects
+   controlling terminal behavior (see term_become_ctty).  For all
+   objects this affects old-style async IO.  Negative values represent
+   pgrps.  This has nothing to do with the owner of a file (as
+   returned by io_stat, and as used for various permission checks by
+   filesystems).  An owner of 0 indicates that there is no owner.  */
+
+error_t
+trivfs_S_io_get_owner (struct trivfs_protid *cred,
+		       mach_port_t reply,
+		       mach_msg_type_name_t reply_type,
+		       pid_t *owner)
+{
+  if (!cred)
+    return EOPNOTSUPP;
+  *owner = 0;
+  return 0;
+}
+
+error_t
+trivfs_S_io_mod_owner (struct trivfs_protid *cred,
+		       mach_port_t reply, mach_msg_type_name_t reply_type,
+		       pid_t owner)
+{
+  if (!cred)
+    return EOPNOTSUPP;
+  else
+    return EINVAL;
+}
+
+/* ---------------------------------------------------------------- */
+
+/* Ask SERVER to provide fsys translation service for us.  REQUESTOR is
+   the bootstrap port supplied to the original translator, and ARGV are
+   the command line arguments.  If the recipient accepts the request, he
+   (or some delegate) should send fsys_startup to REQUESTOR to start the
+   filesystem up.  */
+error_t
+trivfs_S_fsys_forward (mach_port_t server,
+		       mach_port_t reply,
+		       mach_msg_type_name_t replytype,
+		       mach_port_t requestor,
+		       char *argz, size_t argz_len)
+{
+  error_t err;
+  struct fifo_trans *server_trans, *trans;
+  int argc = argz_count (argz, argz_len);
+  char **argv = alloca (sizeof (char *) * (argc + 1));
+  /* SERVER should be our root node.  */
+  struct trivfs_protid *cred =
+    ports_lookup_port (port_bucket, server, server_port_class);
+
+  if (!cred)
+    return EOPNOTSUPP;
+
+  server_trans = cred->po->cntl->hook;
+  assert (server_trans->server);
+
+  argz_extract (argz, argz_len, argv);
+
+  /* Make a new translator, inheriting from its server.  */
+  fifo_trans_create (server_trans, &trans);
+
+  /* Parse the new arguments to change the defaults.  */
+  err = fifo_trans_parse_args (trans, argc, argv, 0);
+
+  if (!err)
+    /* Set our new translator along it's merry way... */
+    fifo_trans_start (trans, requestor);
+
+  ports_port_deref (cred);
+
+  return err;
+}