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/*
* Copyright (C) 2006 Michael Brown <mbrown@fensystems.co.uk>.
*
* 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 of the
* License, or 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 <stdint.h>
#include <string.h>
#include <gpxe/dhcp.h>
#include <gpxe/nvs.h>
/** @file
*
* Non-volatile storage
*
*/
static size_t nvs_options_len ( struct nvs_device *nvs ) {
struct dhcp_option *option;
uint8_t sum;
unsigned int i;
size_t len;
for ( sum = 0, i = 0 ; i < nvs->len ; i++ ) {
sum += * ( ( uint8_t * ) ( nvs->options->data + i ) );
}
if ( sum != 0 ) {
DBG ( "NVS %p has bad checksum %02x; assuming empty\n",
nvs, sum );
return 0;
}
option = nvs->options->data;
if ( option->tag == DHCP_PAD ) {
DBG ( "NVS %p has bad start; assuming empty\n", nvs );
return 0;
}
option = find_dhcp_option ( nvs->options, DHCP_END );
if ( ! option ) {
DBG ( "NVS %p has no end tag; assuming empty\n", nvs );
return 0;
}
len = ( ( void * ) option - nvs->options->data + 1 );
DBG ( "NVS %p contains %zd bytes of options (maximum %zd)\n",
nvs, len, nvs->len );
return len;
}
int nvs_register ( struct nvs_device *nvs ) {
struct dhcp_option *option;
int rc;
nvs->options = alloc_dhcp_options ( nvs->len );
if ( ! nvs->options ) {
DBG ( "NVS %p could not allocate %zd bytes\n", nvs, nvs->len );
rc = -ENOMEM;
goto err;
}
if ( ( rc = nvs->op->read ( nvs, 0, nvs->options->data,
nvs->len ) ) != 0 ) {
DBG ( "NVS %p could not read [0,%zd)\n", nvs, nvs->len );
goto err;
}
nvs->options->len = nvs->options->max_len;
nvs->options->len = nvs_options_len ( nvs );
if ( ! nvs->options->len ) {
option = nvs->options->data;
option->tag = DHCP_END;
nvs->options->len = 1;
}
register_dhcp_options ( nvs->options );
return 0;
err:
free_dhcp_options ( nvs->options );
nvs->options = NULL;
return rc;
}
void nvs_unregister ( struct nvs_device *nvs ) {
if ( nvs->options ) {
unregister_dhcp_options ( nvs->options );
free_dhcp_options ( nvs->options );
nvs->options = NULL;
}
}
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