[Settings] Start revamping the configuration settings API.

Add the concept of an abstract configuration setting, comprising a (DHCP)
tag value and an associated byte sequence.

Add the concept of a settings namespace.

Add functions for extracting string, IPv4 address, and signed and
unsigned integer values from configuration settings (analogous to
dhcp_snprintf(), dhcp_ipv4_option(), etc.).

Update functions for parsing and formatting named/typed options to work
with new settings API.

Update NVO commands and config UI to use new settings API.

src/hci/commands/config_cmd.c

 #include <gpxe/settings.h>
 #include <gpxe/settings_ui.h>
 
-
-#include <gpxe/nvo.h>
-extern struct nvo_block *ugly_nvo_hack;
-
-
 static int config_exec ( int argc, char **argv ) {
-	struct config_context dummy_context;
+	struct settings *settings;
 	int rc;
 
-	if ( argc != 1 ) {
-		printf ( "Usage: %s\n"
+	if ( argc > 2 ) {
+		printf ( "Usage: %s [scope]\n"
 			 "Opens the option configuration console\n", argv[0] );
 		return 1;
 	}
 
-	if ( ! ugly_nvo_hack ) {
-		printf ( "No non-volatile option storage available\n" );
-		return 1;
+	if ( argc == 2 ) {
+		settings = find_settings ( argv[1] );
+		if ( ! settings ) {
+			printf ( "No such scope \"%s\"\n", argv[1] );
+			return 1;
+		}
+	} else {
+		settings = &interactive_settings;
 	}
 
-	dummy_context.options = ugly_nvo_hack->options;
-	if ( ( rc = settings_ui ( &dummy_context ) ) != 0 ) {
+	if ( ( rc = settings_ui ( settings ) ) != 0 ) {
 		printf ( "Could not save settings: %s\n",
 			 strerror ( rc ) );
 		return 1;

src/hci/commands/nvo_cmd.c

 #include <string.h>
 #include <errno.h>
 #include <getopt.h>
-#include <gpxe/nvo.h>
-#include <gpxe/dhcp.h>
 #include <gpxe/settings.h>
 #include <gpxe/command.h>
 
-extern struct nvo_block *ugly_nvo_hack;
-
 static int show_exec ( int argc, char **argv ) {
-	struct config_context dummy_context;
 	char buf[256];
 	int rc;
 
-	if ( ! ugly_nvo_hack ) {
-		printf ( "No non-volatile option storage available\n" );
-		return 1;
-	}
-
 	if ( argc != 2 ) {
 		printf ( "Syntax: %s <identifier>\n", argv[0] );
 		return 1;
 	}
 
-	dummy_context.options = ugly_nvo_hack->options;
-	if ( ( rc = show_named_setting ( &dummy_context, argv[1], buf,
-					 sizeof ( buf ) ) ) < 0 ) {
+	if ( ( rc = get_named_setting ( argv[1], buf, sizeof ( buf ) ) ) < 0 ){
 		printf ( "Could not find \"%s\": %s\n",
-			 argv[1], strerror ( -rc ) );
+			 argv[1], strerror ( rc ) );
 		return 1;
 	}
 
 }
 
 static int set_exec ( int argc, char **argv ) {
-	struct config_context dummy_context;
 	int rc;
 
-	if ( ! ugly_nvo_hack ) {
-		printf ( "No non-volatile option storage available\n" );
-		return 1;
-	}
-
 	if ( argc != 3 ) {
-		printf ( "Syntax: %s <identifier> <value>\n",
-			 argv[0] );
+		printf ( "Syntax: %s <identifier> <value>\n", argv[0] );
 		return 1;
 	}
 
-	dummy_context.options = ugly_nvo_hack->options;
-	if ( ( rc = set_named_setting ( &dummy_context, argv[1],
-					argv[2] ) ) != 0 ) {
+	if ( ( rc = set_named_setting ( argv[1], argv[2] ) ) != 0 ) {
 		printf ( "Could not set \"%s\"=\"%s\": %s\n",
-			 argv[1], argv[2], strerror ( -rc ) );
-		return 1;
-	}
-	
-	if ( nvo_save ( ugly_nvo_hack ) != 0 ) {
-		printf ( "Could not save options to non-volatile storage\n" );
+			 argv[1], argv[2], strerror ( rc ) );
 		return 1;
 	}
 
 }
 
 static int clear_exec ( int argc, char **argv ) {
-	struct config_context dummy_context;
 	int rc;
 
-	if ( ! ugly_nvo_hack ) {
-		printf ( "No non-volatile option storage available\n" );
-		return 1;
-	}
-
 	if ( argc != 2 ) {
-		printf ( "Syntax: %s <identifier>\n",
-			 argv[0] );
+		printf ( "Syntax: %s <identifier>\n", argv[0] );
 		return 1;
 	}
 
-	dummy_context.options = ugly_nvo_hack->options;
-	if ( ( rc = clear_named_setting ( &dummy_context, argv[1] ) ) != 0 ) {
+	if ( ( rc = delete_named_setting ( argv[1] ) ) != 0 ) {
 		printf ( "Could not clear \"%s\": %s\n",
-			 argv[1], strerror ( -rc ) );
+			 argv[1], strerror ( rc ) );
 		return 1;
 	}
 	

src/hci/tui/settings_ui.c

  *
  */
 
-#include <gpxe/nvo.h>
-extern struct nvo_block *ugly_nvo_hack;
-
 /* Colour pairs */
 #define CPAIR_NORMAL	1
 #define CPAIR_SELECT	2
 
 /** A setting widget */
 struct setting_widget {
-	/** Configuration context */
-	struct config_context *context;
+	/** Settings block */
+	struct settings *settings;
 	/** Configuration setting */
-	struct config_setting *setting;
+	struct named_setting *setting;
 	/** Screen row */
 	unsigned int row;
 	/** Screen column */
 };
 
 /** Registered configuration settings */
-static struct config_setting config_settings[0]
-	__table_start ( struct config_setting, config_settings );
-static struct config_setting config_settings_end[0]
-	__table_end ( struct config_setting, config_settings );
-#define NUM_SETTINGS ( ( unsigned ) ( config_settings_end - config_settings ) )
+static struct named_setting named_settings[0]
+	__table_start ( struct named_setting, named_settings );
+static struct named_setting named_settings_end[0]
+	__table_end ( struct named_setting, named_settings );
+#define NUM_SETTINGS ( ( unsigned ) ( named_settings_end - named_settings ) )
 
 static void load_setting ( struct setting_widget *widget ) __nonnull;
 static int save_setting ( struct setting_widget *widget ) __nonnull;
 static void init_setting ( struct setting_widget *widget,
-                           struct config_context *context,
-                           struct config_setting *setting,
+                           struct settings *settings,
+                           struct named_setting *setting,
                            unsigned int row, unsigned int col ) __nonnull;
 static void draw_setting ( struct setting_widget *widget ) __nonnull;
 static int edit_setting ( struct setting_widget *widget, int key ) __nonnull;
 static void init_setting_index ( struct setting_widget *widget,
-                                 struct config_context *context,
+                                 struct settings *settings,
                                  unsigned int index ) __nonnull;
 static void vmsg ( unsigned int row, const char *fmt, va_list args ) __nonnull;
 static void msg ( unsigned int row, const char *fmt, ... ) __nonnull;
 static void valert ( const char *fmt, va_list args ) __nonnull;
 static void alert ( const char *fmt, ... ) __nonnull;
-static void draw_info_row ( struct config_setting *setting ) __nonnull;
-static int main_loop ( struct config_context *context ) __nonnull;
+static void draw_info_row ( struct named_setting *setting ) __nonnull;
+static int main_loop ( struct settings *settings ) __nonnull;
 
 /**
- * Load setting widget value from configuration context
+ * Load setting widget value from configuration settings
  *
  * @v widget		Setting widget
  *
 	widget->editing = 0;
 
 	/* Read current setting value */
-	if ( show_setting ( widget->context, widget->setting,
-			    widget->value, sizeof ( widget->value ) ) < 0 ) {
+	if ( get_typed_setting ( widget->settings, widget->setting->tag,
+				 widget->setting->type, widget->value,
+				 sizeof ( widget->value ) ) < 0 ) {
 		widget->value[0] = '\0';
 	}	
 
 }
 
 /**
- * Save setting widget value back to configuration context
+ * Save setting widget value back to configuration settings
  *
  * @v widget		Setting widget
  */
 static int save_setting ( struct setting_widget *widget ) {
-	return set_setting ( widget->context, widget->setting, widget->value );
+	return set_typed_setting ( widget->settings, widget->setting->tag,
+				   widget->setting->type, widget->value );
 }
 
 /**
  * Initialise setting widget
  *
  * @v widget		Setting widget
- * @v context		Configuration context
+ * @v settings		Settings block
  * @v setting		Configuration setting
  * @v row		Screen row
  * @v col		Screen column
  */
 static void init_setting ( struct setting_widget *widget,
-			   struct config_context *context,
-			   struct config_setting *setting,
+			   struct settings *settings,
+			   struct named_setting *setting,
 			   unsigned int row, unsigned int col ) {
 
 	/* Initialise widget structure */
 	memset ( widget, 0, sizeof ( *widget ) );
-	widget->context = context;
+	widget->settings = settings;
 	widget->setting = setting;
 	widget->row = row;
 	widget->col = col;
  * Initialise setting widget by index
  *
  * @v widget		Setting widget
- * @v context		Configuration context
+ * @v settings		Settings block
  * @v index		Index of setting with settings list
  */
 static void init_setting_index ( struct setting_widget *widget,
-				 struct config_context *context,
+				 struct settings *settings,
 				 unsigned int index ) {
-	init_setting ( widget, context, &config_settings[index],
+	init_setting ( widget, settings, &named_settings[index],
 		       ( SETTINGS_LIST_ROW + index ), SETTINGS_LIST_COL );
 }
 
  *
  * @v setting		Current configuration setting
  */
-static void draw_info_row ( struct config_setting *setting ) {
+static void draw_info_row ( struct named_setting *setting ) {
 	clearmsg ( INFO_ROW );
 	attron ( A_BOLD );
-	msg ( INFO_ROW, "%s (%s) - %s", setting->name,
-	      setting->type->description, setting->description );
+	msg ( INFO_ROW, "%s - %s", setting->name, setting->description );
 	attroff ( A_BOLD );
 }
 
 		      "Ctrl-C - discard changes" );
 	} else {
 		msg ( INSTRUCTION_ROW,
-		      "Ctrl-S - save configuration" );
+		      "Ctrl-X - exit configuration utility" );
 	}
 }
 
-static int main_loop ( struct config_context *context ) {
+static int main_loop ( struct settings *settings ) {
 	struct setting_widget widget;
 	unsigned int current = 0;
 	unsigned int next;
 	draw_title_row();
 	color_set ( CPAIR_NORMAL, NULL );
 	for ( i = ( NUM_SETTINGS - 1 ) ; i >= 0 ; i-- ) {
-		init_setting_index ( &widget, context, i );
+		init_setting_index ( &widget, settings, i );
 		draw_setting ( &widget );
 	}
 
 				if ( next > 0 )
 					next--;
 				break;
-			case CTRL_S:
-				if ( ( rc = nvo_save ( ugly_nvo_hack ) ) != 0){
-					alert ( " Could not save options: %s ",
-						strerror ( rc ) );
-				}
-				return rc;
+			case CTRL_X:
+				return 0;
 			default:
 				edit_setting ( &widget, key );
 				break;
 			}	
 			if ( next != current ) {
 				draw_setting ( &widget );
-				init_setting_index ( &widget, context, next );
+				init_setting_index ( &widget, settings, next );
 				current = next;
 			}
 		}
 	
 }
 
-int settings_ui ( struct config_context *context ) {
+int settings_ui ( struct settings *settings ) {
 	int rc;
 
 	initscr();
 	color_set ( CPAIR_NORMAL, NULL );
 	erase();
 	
-	rc = main_loop ( context );
+	rc = main_loop ( settings );
 
 	endwin();
 

src/include/gpxe/settings.h

  */
 
 #include <stdint.h>
-#include <gpxe/dhcp.h>
 #include <gpxe/tables.h>
+#include <gpxe/list.h>
+#include <gpxe/refcnt.h>
 
-struct config_setting;
+struct settings;
+struct in_addr;
 
-/**
- * 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
+/** Settings block operations */
+struct settings_operations {
+	/** Set value of setting
+	 *
+	 * @v settings		Settings block
+	 * @v tag		Setting tag number
+	 * @v data		Setting data, or NULL to clear setting
+	 * @v len		Length of setting data
+	 * @ret rc		Return status code
+	 */
+	int ( * set ) ( struct settings *settings, unsigned int tag,
+			const void *data, size_t len );
+	/** Get value of setting
+	 *
+	 * @v settings		Settings block
+	 * @v tag		Setting tag number
+	 * @v data		Buffer to fill with setting data
+	 * @v len		Length of buffer
+	 * @ret len		Length of setting data, or negative error
 	 *
-	 * If NULL, all registered DHCP options blocks will be used.
+	 * The actual length of the setting will be returned even if
+	 * the buffer was too small.
 	 */
-	struct dhcp_option_block *options;
+	int ( * get ) ( struct settings *settings, unsigned int tag,
+			void *data, size_t len );
+};
+
+/** A settings block */
+struct settings {
+	/** Reference counter */
+	struct refcnt *refcnt;
+	/** Name */
+	char name[16];
+	/** List of all settings */
+	struct list_head list;
+	/** Settings block operations */
+	struct settings_operations *op;
 };
 
 /**
- * A configuration setting type
+ * A setting type
  *
- * This represents a type of configuration setting (e.g. string, IPv4
- * address, etc.).
+ * This represents a type of setting (e.g. string, IPv4 address,
+ * etc.).
  */
-struct config_setting_type {
+struct setting_type {
 	/** Name
 	 *
 	 * This is the name exposed to the user (e.g. "string").
 	 */
 	const char *name;
-	/** Description */
-	const char *description;
-	/** Show value of setting
+	/** Parse and set value of setting
 	 *
-	 * @v context		Configuration context
-	 * @v setting		Configuration setting
-	 * @v buf		Buffer to contain value
+	 * @v settings		Settings block
+	 * @v tag		Setting tag number
+	 * @v value		Formatted setting data
+	 * @ret rc		Return status code
+	 */
+	int ( * setf ) ( struct settings *settings, unsigned int tag,
+			 const char *value );
+	/** Get and format value of setting
+	 *
+	 * @v settings		Settings block, or NULL to search all blocks
+	 * @v tag		Setting tag number
+	 * @v buf		Buffer to contain formatted value
 	 * @v len		Length of buffer
 	 * @ret len		Length of formatted value, or negative error
 	 */
-	int ( * show ) ( struct config_context *context,
-			 struct config_setting *setting,
+	int ( * getf ) ( struct settings *settings, unsigned int tag,
 			 char *buf, size_t len );
-	/** 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 ( struct config_setting_type, config_setting_types, 01 )
+#define	__setting_type \
+	__table ( struct setting_type, setting_types, 01 )
 
 /**
- * A configuration setting
+ * A named setting
  *
- * This represents a single configuration setting (e.g. "hostname").
+ * This represents a single setting (e.g. "hostname"), encapsulating
+ * the information about the setting's tag number and type.
  */
-struct config_setting {
+struct named_setting {
 	/** Name
 	 *
 	 * This is the human-readable name for the setting.  Where
 	const char *name;
 	/** Description */
 	const char *description;
-	/** DHCP option tag
-	 *
-	 * This is the DHCP tag used to identify the option in DHCP
-	 * packets and stored option blocks.
-	 */
+	/** Setting tag number */
 	unsigned int tag;
-	/** Configuration setting type
+	/** Setting type
 	 *
 	 * This identifies the type of setting (e.g. string, IPv4
 	 * address, etc.).
 	 */
-	struct config_setting_type *type;
+	struct setting_type *type;
 };
 
 /** Declare a configuration setting */
-#define	__config_setting __table ( struct config_setting, config_settings, 01 )
+#define	__named_setting __table ( struct named_setting, named_settings, 01 )
+
+extern struct settings interactive_settings;
+
+extern int get_setting ( struct settings *settings, unsigned int tag,
+			 void *data, size_t len );
+extern int get_setting_len ( struct settings *settings, unsigned int tag );
+extern int get_string_setting ( struct settings *settings, unsigned int tag,
+				char *data, size_t len );
+extern int get_ipv4_setting ( struct settings *settings, unsigned int tag,
+			      struct in_addr *inp );
+extern int get_int_setting ( struct settings *settings, unsigned int tag,
+			     long *value );
+extern int get_uint_setting ( struct settings *settings, unsigned int tag,
+			      unsigned long *value );
+extern struct settings * find_settings ( const char *name );
+extern int set_typed_setting ( struct settings *settings,
+			       unsigned int tag, struct setting_type *type,
+			       const char *value );
+extern int set_named_setting ( const char *name, const char *value );
+extern int get_named_setting ( const char *name, char *buf, size_t len );
 
 /**
- * Show value of setting
+ * Set value of setting
  *
- * @v context		Configuration context
- * @v setting		Configuration setting
- * @v buf		Buffer to contain value
- * @v len		Length of buffer
- * @ret len		Length of formatted value, or negative error
+ * @v settings		Settings block
+ * @v tag		Setting tag number
+ * @v data		Setting data, or NULL to clear setting
+ * @v len		Length of setting data
+ * @ret rc		Return status code
  */
-static inline int show_setting ( struct config_context *context,
-				 struct config_setting *setting,
-				 char *buf, size_t len ) {
-	return setting->type->show ( context, setting, buf, len );
+static inline int set_setting ( struct settings *settings, unsigned int tag,
+				const void *data, size_t len ) {
+	return settings->op->set ( settings, tag, data, len );
 }
 
-extern int set_setting ( struct config_context *context,
-			 struct config_setting *setting,
-			 const char *value );
-
 /**
- * Clear setting
+ * Delete setting
  *
- * @v context		Configuration context
- * @v setting		Configuration setting
+ * @v settings		Settings block
+ * @v tag		Setting tag number
  * @ret rc		Return status code
  */
-static inline int clear_setting ( struct config_context *context,
-				  struct config_setting *setting ) {
-	delete_dhcp_option ( context->options, setting->tag );
-	return 0;
+static inline int delete_setting ( struct settings *settings,
+				   unsigned int tag ) {
+	return set_setting ( settings, tag, NULL, 0 );
 }
 
-/* Function prototypes */
-extern int show_named_setting ( struct config_context *context,
-				const char *name, char *buf, size_t len );
-extern int set_named_setting ( struct config_context *context,
-			       const char *name, const char *value );
+/**
+ * Get and format value of setting
+ *
+ * @v settings		Settings block, or NULL to search all blocks
+ * @v tag		Setting tag number
+ * @v type		Settings type
+ * @v buf		Buffer to contain formatted value
+ * @v len		Length of buffer
+ * @ret len		Length of formatted value, or negative error
+ */
+static inline int get_typed_setting ( struct settings *settings,
+				      unsigned int tag,
+				      struct setting_type *type,
+				      char *buf, size_t len ) {
+	return type->getf ( settings, tag, buf, len );
+}
 
 /**
- * Clear named setting
+ * Delete named setting
  *
- * @v context		Configuration context
- * @v name		Configuration setting name
+ * @v name		Name of setting
  * @ret rc		Return status code
  */
-static inline int clear_named_setting ( struct config_context *context,
-					const char *name ) {
-	return set_named_setting ( context, name, NULL );
+static inline int delete_named_setting ( const char *name ) {
+	return set_named_setting ( name, NULL );
 }
 
 #endif /* _GPXE_SETTINGS_H */

src/include/gpxe/settings_ui.h

  *
  */
 
-struct config_context;
+struct settings;
 
-extern int settings_ui ( struct config_context *context ) __nonnull;
+extern int settings_ui ( struct settings *settings ) __nonnull;
 
 #endif /* _GPXE_SETTINGS_UI_H */