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Added basic infrastructure for manipulating settings.
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Michael Brown committed Aug 11, 2006
1 parent 3b45f05 commit db46972
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148 changes: 148 additions & 0 deletions src/core/settings.c
@@ -0,0 +1,148 @@
/*
* 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 <stdlib.h>
#include <string.h>
#include <errno.h>
#include <assert.h>
#include <gpxe/settings.h>

/** @file
*
* Configuration settings
*
*/

/** Registered configuration setting types */
static struct config_setting_type
config_setting_types[0] __table_start ( config_setting_types );
static struct config_setting_type
config_setting_types_end[0] __table_end ( config_setting_types );

/** Registered configuration settings */
static struct config_setting
config_settings[0] __table_start ( config_settings );
static struct config_setting
config_settings_end[0] __table_end ( config_settings );

/**
* Find configuration setting type
*
* @v name Name
* @ret type Configuration setting type, or NULL
*/
static struct config_setting_type *
find_config_setting_type ( const char *name ) {
struct config_setting_type *type;

for ( type = config_setting_types ; type < config_setting_types_end ;
type++ ) {
if ( strcmp ( name, type->name ) == 0 )
return type;
}
return NULL;
}

/**
* Find configuration setting
*
* @v name Name
* @ret setting Configuration setting, or NULL
*/
static struct config_setting * find_config_setting ( const char *name ) {
struct config_setting *setting;

for ( setting = config_settings ; setting < config_settings_end ;
setting++ ) {
if ( strcmp ( name, setting->name ) == 0 )
return setting;
}
return NULL;
}

/**
* Find or build configuration setting
*
* @v name Name
* @v tmp_setting Temporary buffer for constructing a setting
* @ret setting Configuration setting, or NULL
*
* Find setting if it exists. If it doesn't exist, but the name is of
* the form "<num>.<type>" (e.g. "12.string"), then construct a
* setting for that tag and data type, and return it. The constructed
* setting will be placed in the temporary buffer.
*/
static struct config_setting *
find_or_build_config_setting ( const char *name,
struct config_setting *tmp_setting ) {
struct config_setting *setting;
char *separator;

/* Look in the list of registered settings first */
setting = find_config_setting ( name );
if ( setting )
return setting;

/* If name is of the form "<num>.<type>", try to construct a setting */
setting = tmp_setting;
memset ( setting, 0, sizeof ( *setting ) );
setting->name = name;
setting->tag = strtoul ( name, &separator, 10 );
if ( *separator != '.' )
return NULL;
setting->type = find_config_setting_type ( separator + 1 );
if ( ! setting->type )
return NULL;
return setting;
}

/** Show value of setting
*
* @v context Configuration context
* @v name Configuration setting name
* @ret value Setting value (as a string), or NULL
*/
const char * ( show_setting ) ( struct config_context *context,
const char *name ) {
struct config_setting *setting;
struct config_setting tmp_setting;

setting = find_or_build_config_setting ( name, &tmp_setting );
if ( ! setting )
return NULL;
return setting->type->show ( context, setting );
}

/** Set value of setting
*
* @v context Configuration context
* @v name Configuration setting name
* @v value Setting value (as a string)
* @ret rc Return status code
*/
int ( set_setting ) ( struct config_context *context, const char *name,
const char *value ) {
struct config_setting *setting;
struct config_setting tmp_setting;

setting = find_or_build_config_setting ( name, &tmp_setting );
if ( ! setting )
return -ENOENT;
return setting->type->set ( context, setting, value );
}
103 changes: 103 additions & 0 deletions src/include/gpxe/settings.h
@@ -0,0 +1,103 @@
#ifndef _GPXE_SETTINGS_H
#define _GPXE_SETTINGS_H

/** @file
*
* Configuration settings
*
*/

#include <stdint.h>
#include <gpxe/dhcp.h>
#include <gpxe/tables.h>

struct config_setting;

/**
* A configuration context
*
* This identifies the context within which settings are inspected and
* changed. For example, the context might be global, or might be
* restricted to the settings stored in NVS on a particular device.
*/
struct config_context {
/** DHCP options block, or NULL
*
* If NULL, all registered DHCP options blocks will be used.
*/
struct dhcp_option_block *options;
};

/**
* A configuration setting type
*
* This represents a type of configuration setting (e.g. string, IPv4
* address, etc.).
*/
struct config_setting_type {
/** Name
*
* This is the name exposed to the user (e.g. "string").
*/
const char *name;
/** Show value of setting
*
* @v context Configuration context
* @v setting Configuration setting
* @ret value Setting value (as a string), or NULL
*/
const char * ( * show ) ( struct config_context *context,
struct config_setting *setting );
/** Set value of setting
*
* @v context Configuration context
* @v setting Configuration setting
* @v value Setting value (as a string)
* @ret rc Return status code
*/
int ( * set ) ( struct config_context *context,
struct config_setting *setting,
const char *value );
};

/** Declare a configuration setting type */
#define __config_setting_type __table ( config_setting_types, 01 )

/**
* A configuration setting
*
* This represents a single configuration setting (e.g. "hostname").
*/
struct config_setting {
/** Name
*
* This is the human-readable name for the setting. Where
* possible, it should match the name used in dhcpd.conf (see
* dhcp-options(5)).
*/
const char *name;
/** DHCP option tag
*
* This is the DHCP tag used to identify the option in DHCP
* packets and stored option blocks.
*/
unsigned int tag;
/** Configuration setting type
*
* This identifies the type of setting (e.g. string, IPv4
* address, etc.).
*/
struct config_setting_type *type;
};

/** Declare a configuration setting */
#define __config_setting __table ( config_settings, 01 )

/* Function prototypes */

extern const char * ( show_setting ) ( struct config_context *context,
const char *name );
extern int ( set_setting ) ( struct config_context *context, const char *name,
const char *value );

#endif /* _GPXE_SETTINGS_H */

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