Initial revision

1 files changed, 394 insertions, 0 deletions

diff --git a/trans/null.c b/trans/null.c
new file mode 100644
index 00000000..3c6cb054
--- /dev/null
+++ b/trans/null.c
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+/* A translator for providing endless empty space and immediate eof.
+
+   Copyright (C) 1995 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 <hurd.h>
+#include <hurd/ports.h>
+#include <hurd/trivfs.h>
+#include <hurd/fsys.h>
+
+#include <stdio.h>
+#include <error.h>
+#include <assert.h>
+#include <string.h>
+#include <fcntl.h>
+#include <limits.h>
+
+/* ---------------------------------------------------------------- */
+
+/* Ports port types.  */
+#define PT_CTL 0
+#define PT_NODE 1
+
+/* If true, then reading from this device will yield an endless stream of
+   zeros instead of immediate EOF.  This also makes it mappable.  */
+static int provide_zeros = 0;
+
+void
+main (int argc, char **argv)
+{
+  error_t err;
+  mach_port_t bootstrap, control, realnode;
+  struct trivfs_control *trivfs_control;
+
+  task_get_bootstrap_port (mach_task_self (), &bootstrap);
+  if (bootstrap == MACH_PORT_NULL)
+    error(1, 0, "must be started as a translator");
+  
+  if (argc == 2 &&
+      (strcmp(argv[1], "-z") == 0 || strcmp(argv[1], "--zero") == 0))
+    provide_zeros = 1;
+  else if (argc != 1)
+    {
+      fprintf(stderr, "Usage: %s [-z|--zero]", program_invocation_name);
+      exit(1);
+    }
+
+  _libports_initialize();
+
+  /* Reply to our parent */
+  control = trivfs_handle_port (MACH_PORT_NULL, PT_CTL, PT_NODE);
+  err = fsys_startup (bootstrap, control, MACH_MSG_TYPE_MAKE_SEND, &realnode);
+  if (err)
+    error(1, err, "starting translator");
+
+  /* Install the returned realnode for trivfs's use */
+  trivfs_control = ports_check_port_type (control, PT_CTL);
+  assert (trivfs_control);
+  ports_change_hardsoft (trivfs_control, 1);
+  trivfs_control->underlying = realnode;
+  ports_done_with_port (trivfs_control);
+
+  /* Launch. */
+  ports_manage_port_operations_onethread ();
+
+  exit(0);
+}
+
+/* ---------------------------------------------------------------- */
+/* Trivfs hooks  */
+
+int trivfs_fstype = FSTYPE_DEV;
+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;
+
+int trivfs_protid_porttypes[] = {PT_NODE};
+int trivfs_cntl_porttypes[] = {PT_CTL};
+int trivfs_protid_nporttypes = 1;
+int trivfs_cntl_nporttypes = 1;
+
+void
+trivfs_modify_stat (struct stat *st)
+{
+  st->st_blksize = 1;
+
+  st->st_size = 0;
+  st->st_blocks = 0;
+
+  st->st_mode &= ~S_IFMT;
+  st->st_mode |= S_IFCHR;
+}
+
+error_t
+trivfs_goaway (int flags, mach_port_t realnode, int ctltype, int pitype)
+{
+  exit(0);
+}
+
+/* ---------------------------------------------------------------- */
+/* Ports hooks  */
+
+void (*ports_cleanroutines[])(void *) =
+{
+  [PT_CTL] = trivfs_clean_cntl,
+  [PT_NODE] = trivfs_clean_protid,
+};
+
+int
+ports_demuxer (mach_msg_header_t *inp, mach_msg_header_t *outp)
+{
+  return trivfs_demuxer(inp, outp);
+}
+
+/* This will be called whenever there have been no requests to the server for
+   a significant period of time.  NHARD is the number of live hard ports;
+   NSOFT is the number of live soft ports.  This function is called while an
+   internal lock is held, so it cannot reliably call any other functions of
+   the ports library. */
+void
+ports_notice_idle (int nhard, int nsoft)
+{
+  if (nhard == 0)
+    exit(0);
+}
+
+/* This will be called whenever there are no hard ports or soft ports
+   allocated.  This function is called while an internal lock is held, so it
+   cannot reliably call any other functions of the ports library. */
+void
+ports_no_live_ports ()
+{
+  exit(0);
+}
+
+/* This will be called whenever there are no hard ports allocated but there
+   are still some soft ports.  This function is called while an internal lock
+   is held, so it cannot reliably call any other functions of the ports
+   library. */
+void
+ports_no_hard_ports ()
+{
+}
+
+/* ---------------------------------------------------------------- */
+
+/* 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.  */
+kern_return_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;		/* XXX should work! */
+}
+
+/* ---------------------------------------------------------------- */
+
+/* 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.  */
+kern_return_t
+trivfs_S_io_read(struct trivfs_protid *cred,
+		 mach_port_t reply, mach_msg_type_name_t replytype,
+		 vm_address_t *data,
+		 mach_msg_type_number_t *datalen,
+		 off_t offs,
+		 mach_msg_type_number_t amt)
+{
+  error_t err = 0;
+
+  if (!cred)
+    err = EOPNOTSUPP;
+  else if (!(cred->po->openmodes & O_READ))
+    err = EBADF;
+  else if (provide_zeros)
+    {
+      if (amt > *datalen)
+	err = vm_allocate(mach_task_self(), data, amt, 1);
+      else
+	bzero((void *)*data, amt);
+      *datalen = amt;
+    }
+  else
+    *datalen = 0;
+
+  return 0;
+}
+
+/* ---------------------------------------------------------------- */
+
+/* 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.  */
+kern_return_t
+trivfs_S_io_readable (struct trivfs_protid *cred,
+		      mach_port_t reply, mach_msg_type_name_t replytype,
+		      mach_msg_type_number_t *amount)
+{
+  if (!cred)
+    return EOPNOTSUPP;
+  else if (!(cred->po->openmodes & O_READ))
+    return EINVAL;
+  else if (provide_zeros)
+    *amount = INT_MAX;
+  else
+    *amount = 0;
+  return 0;
+}
+
+/* ---------------------------------------------------------------- */
+
+/* Change current read/write offset */
+kern_return_t
+trivfs_S_io_seek (struct trivfs_protid *cred,
+		  mach_port_t reply, mach_msg_type_name_t replytype,
+		  off_t offset, int whence, off_t *new_offset)
+{
+  if (!cred)
+    return EOPNOTSUPP;
+  *new_offset = 0;
+  return 0;
+}
+
+/* ---------------------------------------------------------------- */
+
+/* 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.  */
+kern_return_t
+trivfs_S_io_select (struct trivfs_protid *cred,
+		    mach_port_t reply, mach_msg_type_name_t replytype,
+		    int *type, int *tag)
+{
+  if (!cred)
+    return EOPNOTSUPP;
+  else if (((*type & SELECT_READ) && !(cred->po->openmodes & O_READ))
+	   || ((*type & SELECT_WRITE) && !(cred->po->openmodes & O_WRITE)))
+    return EBADF;
+  else
+    *type &= ~SELECT_URG;
+  return 0;
+}
+
+/* ---------------------------------------------------------------- */
+
+/* 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.  */
+kern_return_t
+trivfs_S_io_write (struct trivfs_protid *cred,
+		   mach_port_t reply, mach_msg_type_name_t replytype,
+		   vm_address_t data, mach_msg_type_number_t datalen,
+		   off_t offs, mach_msg_type_number_t *amt)
+{
+  if (!cred)
+    return EOPNOTSUPP;
+  else if (!(cred->po->openmodes & O_WRITE))
+    return EBADF;
+  *amt = datalen;
+  return 0;
+}
+
+/* ---------------------------------------------------------------- */
+
+/* Truncate file.  */
+kern_return_t
+trivfs_S_file_truncate (struct trivfs_protid *cred, off_t size)
+{
+  /* The zero device is `big and fixed size', so can't be truncated; the null
+     device is always really truncated.  */
+  return provide_zeros ? EINVAL : 0;
+}
+
+/* ---------------------------------------------------------------- */
+/* 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. */
+
+kern_return_t
+trivfs_S_io_get_openmodes (struct trivfs_protid *cred,
+			   mach_port_t reply, mach_msg_type_name_t replytype,
+			   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 replytype,
+			      int mode)
+{
+  if (!cred)
+    return EOPNOTSUPP;
+  else
+    return 0;
+}
+
+kern_return_t
+trivfs_S_io_set_some_openmodes (struct trivfs_protid *cred,
+				mach_port_t reply,
+				mach_msg_type_name_t replytype,
+				int bits)
+{
+  if (!cred)
+    return EOPNOTSUPP;
+  else
+    return 0;
+}
+
+kern_return_t
+trivfs_S_io_clear_some_openmodes (struct trivfs_protid *cred,
+				  mach_port_t reply,
+				  mach_msg_type_name_t replytype,
+				  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.  */
+
+kern_return_t
+trivfs_S_io_get_owner (struct trivfs_protid *cred,
+		       mach_port_t reply,
+		       mach_msg_type_name_t replytype,
+		       pid_t *owner)
+{
+  if (!cred)
+    return EOPNOTSUPP;
+  *owner = 0;
+  return 0;
+}
+
+kern_return_t
+trivfs_S_io_mod_owner (struct trivfs_protid *cred,
+		       mach_port_t reply, mach_msg_type_name_t replytype,
+		       pid_t owner)
+{
+  if (!cred)
+    return EOPNOTSUPP;
+  else
+    return EINVAL;
+}