[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.

1 files changed, 122 insertions, 80 deletions

diff --git a/src/include/gpxe/settings.h b/src/include/gpxe/settings.h
index 1b9c059b..7198399e 100644
--- a/src/include/gpxe/settings.h
+++ b/src/include/gpxe/settings.h
@@ -8,73 +8,96 @@
  */
 
 #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
@@ -84,71 +107,90 @@ struct config_setting {
 	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 */