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-rw-r--r--trans/new-fifo.c810
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;
+}