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/* Store wire decoding
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 <string.h>
#include <malloc.h>
#include "store.h"
/* The maximum number of runs for which we allocate run vectors on the stack. */
#define MAX_STACK_RUNS (16*1024 / sizeof (struct store_run))
/* Decodes the standard leaf encoding that's common to various builtin
formats, and calls CREATE to actually create the store. */
error_t
store_std_leaf_decode (struct store_enc *enc,
store_std_leaf_create_t create,
struct store **store)
{
char *misc;
error_t err;
int type, flags, i;
mach_port_t port;
size_t block_size, num_runs, name_len, misc_len;
/* Make sure there are enough encoded ints and ports. */
if (enc->cur_int + 6 > enc->num_ints || enc->cur_port + 1 > enc->num_ports)
return EINVAL;
/* Read encoded ints. */
type = enc->ints[enc->cur_int++];
flags = enc->ints[enc->cur_int++];
block_size = enc->ints[enc->cur_int++];
num_runs = enc->ints[enc->cur_int++];
name_len = enc->ints[enc->cur_int++];
misc_len = enc->ints[enc->cur_int++];
/* Make sure there are enough encoded offsets and data. */
if (enc->cur_offset + num_runs * 2 > enc->num_offsets
|| enc->cur_data + name_len + misc_len > enc->data_len)
return EINVAL;
if (enc->data[enc->cur_data + name_len - 1] != '\0')
return EINVAL; /* Name not terminated. */
misc = malloc (misc_len);
if (! misc)
return ENOMEM;
/* Read encoded ports (be careful to deallocate this if we barf). */
port = enc->ports[enc->cur_port++];
/* Since the runs are passed in an array of off_t pairs, and we use struct
store_run, we have to make a temporary array to hold the (probably
bitwise identical) converted representation to pass to CREATE. */
if (num_runs <= MAX_STACK_RUNS)
{
struct store_run runs[num_runs];
off_t *e = enc->offsets + enc->cur_offset;
for (i = 0; i < num_runs; i++)
{
runs[i].start = *e++;
runs[i].length = *e++;
}
err = (*create)(port, flags, block_size, runs, num_runs, store);
}
else
/* Ack. Too many runs to allocate the temporary RUNS array on the stack.
This will probably never happen. */
{
struct store_run *runs = malloc (num_runs * sizeof (struct store_run));
if (runs)
{
off_t *e = enc->offsets + enc->cur_offset;
for (i = 0; i < num_runs; i++)
{
runs[i].start = *e++;
runs[i].length = *e++;
}
err = (*create)(port, flags, block_size, runs, num_runs, store);
free (runs);
}
else
err = ENOMEM;
}
if (err)
{
mach_port_deallocate (mach_task_self (), port);
free (misc);
}
else
{
(*store)->flags = flags;
(*store)->misc = misc;
(*store)->misc_len = misc_len;
}
return err;
}
/* Decode ENC, either returning a new store in STORE, or an error. CLASSES
defines the mapping from hurd storage class ids to store classes; if it is
0, STORE_STD_CLASSES is used. If nothing else is to be done with ENC, its
contents may then be freed using store_enc_dealloc. */
error_t
store_decode (struct store_enc *enc, struct store_class *classes,
struct store **store)
{
if (enc->cur_int >= enc->num_ints)
/* The first int should always be the type. */
return EINVAL;
if (! classes)
classes = store_std_classes;
while (classes)
if (classes->id == enc->ints[enc->cur_int])
if (classes->decode)
return (*classes->decode) (enc, classes, store);
else
return EOPNOTSUPP;
return EINVAL;
}
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