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/* Direct store mapping
Copyright (C) 1997 Free Software Foundation, Inc.
Written by Miles Bader <miles@gnu.org>
This file is part of the GNU Hurd.
The GNU Hurd 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.
The GNU Hurd 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., 59 Temple Place - Suite 330, Boston, MA 02111, USA. */
#include <hurd.h>
#include <hurd/io.h>
#include "store.h"
/* Return a memory object paging on STORE. [among other reasons,] this may
fail because store contains non-contiguous regions on the underlying
object. In such a case you can try calling some of the routines below to
get a pager. */
error_t
store_map (const struct store *store, vm_prot_t prot,
mach_port_t *memobj)
{
error_t (*map) (const struct store *store, vm_prot_t prot,
mach_port_t *memobj) =
store->class->map;
error_t err = map ? (*map) (store, prot, memobj) : EOPNOTSUPP;
if (err == EOPNOTSUPP && store->source != MACH_PORT_NULL)
/* Can't map the store directly, but we know it represents the file
STORE->source, so we can try mapping that instead. */
{
mach_port_t rd_memobj, wr_memobj;
int ro = (store->flags & STORE_HARD_READONLY);
if ((prot & VM_PROT_WRITE) && ro)
return EACCES;
err = io_map (store->port, &rd_memobj, &wr_memobj);
if (! err)
{
*memobj = rd_memobj;
if (!ro || wr_memobj != MACH_PORT_NULL)
/* If either we or the server think this object is writable, then
the write-memory-object must be the same as the read one (if
we only care about reading, then it can be null too). */
{
if (rd_memobj == wr_memobj)
{
if (rd_memobj != MACH_PORT_NULL)
mach_port_mod_refs (mach_task_self (), rd_memobj,
MACH_PORT_RIGHT_SEND, -1);
}
else
{
if (rd_memobj != MACH_PORT_NULL)
mach_port_deallocate (mach_task_self (), rd_memobj);
if (wr_memobj != MACH_PORT_NULL)
mach_port_deallocate (mach_task_self (), wr_memobj);
err = EOPNOTSUPP;
}
}
}
}
return err;
}
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