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/* Store backend using a Mach memory object
Copyright (C) 2001 Free Software Foundation, Inc.
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 "store.h"
#include <hurd.h>
#include <hurd/sigpreempt.h>
#include <sys/mman.h>
#include <string.h>
#include <assert.h>
/* Return a new store in STORE referring to the memory object MEMOBJ.
Consumes the send right MEMOBJ. */
error_t
store_memobj_create (memory_object_t memobj, int flags, size_t block_size,
const struct store_run *runs, size_t num_runs,
struct store **store)
{
return _store_create (&store_memobj_class,
memobj, flags, block_size, runs, num_runs, 0, store);
}
/* This one is pretty easy. */
static error_t
memobj_map (const struct store *store, vm_prot_t prot, mach_port_t *memobj)
{
*memobj = store->port;
return mach_port_mod_refs (mach_task_self (), *memobj,
MACH_PORT_RIGHT_SEND, +1);
}
static error_t /* swiped from libpager's pager_memcpy */
memobj_memcpy (memory_object_t memobj,
vm_offset_t offset, void *other, size_t *size,
vm_prot_t prot)
{
vm_address_t window = 0;
vm_size_t windowsize = 8 * vm_page_size;
size_t to_copy = *size;
error_t err;
error_t copy (struct hurd_signal_preemptor *preemptor)
{
while (to_copy > 0)
{
size_t pageoff = offset & (vm_page_size - 1);
if (window)
/* Deallocate the old window. */
munmap ((caddr_t) window, windowsize);
/* Map in and copy a standard-sized window, unless that is
more than the total left to be copied. */
if (windowsize > pageoff + to_copy)
windowsize = pageoff + to_copy;
window = 0;
err = vm_map (mach_task_self (), &window, windowsize, 0, 1,
memobj, offset - pageoff, 0,
prot, prot, VM_INHERIT_NONE);
if (err)
return 0;
/* Realign the fault preemptor for the new mapping window. */
preemptor->first = window;
preemptor->last = window + windowsize;
if (prot == VM_PROT_READ)
memcpy (other, (const void *) window + pageoff,
windowsize - pageoff);
else
memcpy ((void *) window + pageoff, other, windowsize - pageoff);
offset += windowsize - pageoff;
other += windowsize - pageoff;
to_copy -= windowsize - pageoff;
}
return 0;
}
jmp_buf buf;
void fault (int signo, long int sigcode, struct sigcontext *scp)
{
assert (scp->sc_error == EKERN_MEMORY_ERROR);
err = EIO;
to_copy -= sigcode - window;
longjmp (buf, 1);
}
if (to_copy == 0)
/* Short-circuit return if nothing to do.
ERR would not be initialized by the copy loop in this case. */
return 0;
if (setjmp (buf) == 0)
hurd_catch_signal (sigmask (SIGSEGV) | sigmask (SIGBUS),
window, window + windowsize,
©, (sighandler_t) &fault);
if (window)
munmap ((caddr_t) window, windowsize);
*size -= to_copy;
return err;
}
static error_t
memobj_read (struct store *store,
store_offset_t addr, size_t index, size_t amount,
void **buf, size_t *len)
{
addr <<= store->log2_block_size;
if (((size_t) addr & (vm_page_size - 1)) == 0)
{
*len = amount;
return vm_map (mach_task_self (), (vm_address_t *) buf, amount,
0, 1, store->port, addr << store->log2_block_size, 0,
VM_PROT_READ, VM_PROT_ALL, VM_INHERIT_NONE);
}
else
{
error_t err;
int alloced = 0;
if (*len < amount)
{
*buf = mmap (0, amount, PROT_READ|PROT_WRITE, MAP_ANON, 0, 0);
if (*buf == MAP_FAILED)
return errno;
alloced = 1;
}
*len = amount;
err = memobj_memcpy (store->port, addr, *buf, len, VM_PROT_READ);
if (err && alloced)
munmap (*buf, amount);
else if (alloced && round_page (*len) < round_page (amount))
munmap (*buf + round_page (*len),
round_page (amount) - round_page (*len));
return err;
}
}
static error_t
memobj_write (struct store *store,
store_offset_t addr, size_t index,
const void *buf, size_t len, size_t *amount)
{
*amount = len;
return memobj_memcpy (store->port, addr << store->log2_block_size,
(void *) buf, amount, VM_PROT_WRITE);
}
static error_t
memobj_decode (struct store_enc *enc, const struct store_class *const *classes,
struct store **store)
{
return store_std_leaf_decode (enc, store_memobj_create, store);
}
const struct store_class
store_memobj_class =
{
STORAGE_MEMORY, "memobj",
map: memobj_map,
read: memobj_read,
write: memobj_write,
allocate_encoding: store_std_leaf_allocate_encoding,
encode: store_std_leaf_encode,
decode: memobj_decode,
};
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