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/* Block address translation
Copyright (C) 1996 Free Software Foundation, Inc.
Written by Miles Bader <miles@gnu.ai.mit.edu>
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., 675 Mass Ave, Cambridge, MA 02139, USA. */
#include <malloc.h>
#include <hurd/fs.h>
#include "store.h"
static error_t
remap_read (struct store *store,
off_t addr, size_t index, size_t amount,
void **buf, size_t *len)
{
return store_read (store->children[0], addr, amount, buf, len);
}
static error_t
remap_write (struct store *store,
off_t addr, size_t index, void *buf, size_t len,
size_t *amount)
{
return store_write (store->children[0], addr, buf, len, amount);
}
error_t
remap_allocate_encoding (const struct store *store, struct store_enc *enc)
{
enc->num_ints += 3;
enc->num_offsets += store->num_runs * 2;
return store_allocate_child_encodings (store, enc);
}
error_t
remap_encode (const struct store *store, struct store_enc *enc)
{
int i;
enc->ints[enc->cur_int++] = store->class->id;
enc->ints[enc->cur_int++] = store->flags;
enc->ints[enc->cur_int++] = store->num_runs;
for (i = 0; i < store->num_runs; i++)
{
enc->offsets[enc->cur_offset++] = store->runs[i].start;
enc->offsets[enc->cur_offset++] = store->runs[i].length;
}
return store_encode_children (store, enc);
}
error_t
remap_decode (struct store_enc *enc, const struct store_class *const *classes,
struct store **store)
{
if (enc->cur_int + 3 > enc->num_ints)
return EINVAL;
else
{
int type = enc->ints[enc->cur_int++];
int flags = enc->ints[enc->cur_int++];
int num_runs = enc->ints[enc->cur_int++];
error_t create_remap (const struct store_run *runs, size_t num_runs)
{
struct store *source;
error_t err = store_decode_children (enc, 1, classes, &source);
if (! err)
err = store_remap_create (source, runs, num_runs, flags, store);
return err;
}
return store_with_decoded_runs (enc, num_runs, create_remap);
}
}
struct store_class
store_remap_class =
{
STORAGE_REMAP, "remap", remap_read, remap_write,
remap_allocate_encoding, remap_encode, remap_decode,
store_set_child_flags, store_clear_child_flags
};
/* Return a new store in STORE that reflects the blocks in RUNS & RUNS_LEN
from SOURCE; SOURCE is consumed, but RUNS is not. Unlike the
store_remap function, this function always operates by creating a new
store of type `remap' which has SOURCE as a child, and so may be less
efficient than store_remap for some types of stores. */
error_t
store_remap_create (struct store *source,
const struct store_run *runs, size_t num_runs,
int flags, struct store **store)
{
error_t err;
*store = _make_store (&store_remap_class, MACH_PORT_NULL, flags | source->flags,
source->block_size, runs, num_runs, 0);
if (! *store)
return ENOMEM;
err = store_set_children (*store, &source, 1);
if (err)
store_free (*store);
return err;
}
/* For each run in RUNS, of length NUM_RUNS, translate the */
error_t
store_remap_runs (const struct store_run *runs, size_t num_runs,
const struct store_run *base_runs, size_t num_base_runs,
struct store_run **xruns, size_t *num_xruns)
{
int i, j;
size_t xruns_alloced = num_runs + num_base_runs;
/* Add the single run [ADDR, LEN) to *XRUNS, returning true if successful. */
int add_run (off_t addr, off_t len)
{
if (*num_xruns == xruns_alloced)
/* Make some more space in *XRUNS. */
{
struct store_run *new;
xruns_alloced *= 2;
new = realloc (*xruns, xruns_alloced * sizeof (struct store_run));
if (! new)
return 0;
*xruns = new;
}
(*xruns)[(*num_xruns)++] = (struct store_run){ addr, len };
return 1;
}
*xruns = malloc (xruns_alloced * sizeof (struct store_run));
if (! *xruns)
return ENOMEM;
/* Clean up and return error code CODE. */
#define ERR(code) do { free (*xruns); return (code); } while (0)
for (i = 0; i < num_runs; i++)
{
off_t addr = runs[i].start, left = runs[i].length;
if (addr >= 0)
for (j = 0; j < num_base_runs && left > 0; j++)
{
off_t baddr = base_runs[j].start;
off_t blen = base_runs[j].length;
if (addr >= blen)
addr -= blen;
else if (baddr < 0)
/* A hole, which is invalid. */
ERR (EINVAL);
else
/* Add another output run. */
{
off_t len = blen - addr; /* Size of next output run. */
if (! add_run (baddr + addr, len > left ? left : len))
ERR (ENOMEM);
addr = 0;
left -= len;
}
}
else
/* a hole */
if (! add_run (-1, left))
ERR (ENOMEM);
}
if (xruns_alloced > *num_xruns)
*xruns = realloc (*xruns, *num_xruns * sizeof (struct store_run));
return 0;
}
/* Return a store in STORE that reflects the blocks in RUNS & RUNS_LEN from
SOURCE; SOURCE is consumed, but not RUNS. Unlike the store_remap_create
function, this may simply modify SOURCE and return it. */
error_t
store_remap (struct store *source,
const struct store_run *runs, size_t num_runs,
struct store **store)
{
if (source->class->remap)
/* Use the class-specific remaping function. */
return (* source->class->remap) (source, runs, num_runs, store);
else
/* Just replace SOURCE's runs-list by an appropiately translated RUNS. */
{
struct store_run *xruns = 0;
size_t num_xruns = 0;
error_t err =
store_remap_runs (runs, num_runs, source->runs, source->num_runs,
&xruns, &num_xruns);
if (! err)
{
/* Don't use store_set_runs -- we've already allocated the
storage. */
free (source->runs);
source->runs = xruns;
source->num_runs = num_xruns;
source->flags &= ~STORE_ENFORCED;
source->end = 0; /* Needed to make _store_derive work. */
_store_derive (source);
*store = source;
}
return err;
}
}
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