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[settings] Allow for autovivification of settings blocks
Allow for settings blocks to be created on demand. This allows for constructions such as set defaults/filename http://bootserver/bootfile set defaults/priority 0xff dhcp net0 chain ${filename} which will boot from the DHCP-provided filename, or from "http://bootserver/bootfile" if the DHCP server does not provide a filename. (Note that "priority" gets interpreted as a signed integer, so setting "defaults/priority" to 0xff will cause the "defaults" settings block to have an effective priority of -1.)
This commit is contained in:
Michael Brown
parent
f95c919741
commit
ec24672db7
@ -117,6 +117,108 @@ struct simple_settings simple_settings_root = {
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/** Root settings block */
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#define settings_root simple_settings_root.settings
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/**
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* Find child named settings block
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*
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* @v parent Parent settings block
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* @v name Name within this parent
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* @ret settings Settings block, or NULL
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*/
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static struct settings * find_child_settings ( struct settings *parent,
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const char *name ) {
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struct settings *settings;
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/* Treat empty name as meaning "this block" */
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if ( ! *name )
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return parent;
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/* Look for child with matching name */
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list_for_each_entry ( settings, &parent->children, siblings ) {
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if ( strcmp ( settings->name, name ) == 0 )
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return settings;
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}
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return NULL;
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}
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/**
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* Find or create child named settings block
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*
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* @v parent Parent settings block
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* @v name Name within this parent
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* @ret settings Settings block, or NULL
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*/
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static struct settings * autovivify_child_settings ( struct settings *parent,
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const char *name ) {
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struct {
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struct simple_settings simple;
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char name[ strlen ( name ) + 1 /* NUL */ ];
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} *new_child;
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struct settings *settings;
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/* Return existing settings, if existent */
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if ( ( settings = find_child_settings ( parent, name ) ) != NULL )
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return settings;
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/* Create new simple settings block */
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new_child = zalloc ( sizeof ( *new_child ) );
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if ( ! new_child ) {
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DBGC ( parent, "Settings %p could not create child %s\n",
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parent, name );
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return NULL;
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}
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memcpy ( new_child->name, name, sizeof ( new_child->name ) );
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simple_settings_init ( &new_child->simple, NULL, new_child->name );
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settings = &new_child->simple.settings;
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register_settings ( settings, parent );
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return settings;
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}
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/**
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* Parse settings block name
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*
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* @v name Name
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* @v get_child Function to find or create child settings block
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* @ret settings Settings block, or NULL
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*/
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static struct settings *
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parse_settings_name ( const char *name,
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struct settings * ( * get_child ) ( struct settings *,
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const char * ) ) {
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struct settings *settings = &settings_root;
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char name_copy[ strlen ( name ) + 1 ];
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char *subname;
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char *remainder;
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/* Create modifiable copy of name */
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memcpy ( name_copy, name, sizeof ( name_copy ) );
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remainder = name_copy;
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/* Parse each name component in turn */
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while ( remainder ) {
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subname = remainder;
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remainder = strchr ( subname, '.' );
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if ( remainder )
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*(remainder++) = '\0';
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settings = get_child ( settings, subname );
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if ( ! settings )
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break;
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}
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return settings;
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}
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/**
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* Find named settings block
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*
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* @v name Name
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* @ret settings Settings block, or NULL
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*/
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struct settings * find_settings ( const char *name ) {
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return parse_settings_name ( name, find_child_settings );
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}
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/**
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* Apply all settings
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*
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@ -228,52 +330,6 @@ void unregister_settings ( struct settings *settings ) {
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apply_settings();
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}
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/**
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* Find child named settings block
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*
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* @v parent Parent settings block
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* @v name Name within this parent
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* @ret settings Settings block, or NULL
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*/
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struct settings * find_child_settings ( struct settings *parent,
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const char *name ) {
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struct settings *settings;
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size_t len;
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/* NULL parent => add to settings root */
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if ( parent == NULL )
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parent = &settings_root;
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/* Look for a child whose name matches the initial component */
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list_for_each_entry ( settings, &parent->children, siblings ) {
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len = strlen ( settings->name );
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if ( strncmp ( name, settings->name, len ) != 0 )
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continue;
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if ( name[len] == 0 )
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return settings;
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if ( name[len] == '.' )
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return find_child_settings ( settings,
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( name + len + 1 ) );
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}
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return NULL;
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}
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/**
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* Find named settings block
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*
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* @v name Name
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* @ret settings Settings block, or NULL
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*/
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struct settings * find_settings ( const char *name ) {
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/* If name is empty, use the root */
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if ( ! *name )
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return &settings_root;
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return find_child_settings ( &settings_root, name );
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}
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/******************************************************************************
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*
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* Core settings routines
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@ -641,6 +697,7 @@ static struct setting_type * find_setting_type ( const char *name ) {
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* Parse setting name
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*
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* @v name Name of setting
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* @v get_child Function to find or create child settings block
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* @v settings Settings block to fill in
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* @v setting Setting to fill in
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* @ret rc Return status code
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@ -649,8 +706,11 @@ static struct setting_type * find_setting_type ( const char *name ) {
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* "[settings_name/]tag_name[:type_name]" and fills in the appropriate
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* fields.
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*/
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static int parse_setting_name ( const char *name, struct settings **settings,
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struct setting *setting ) {
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static int
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parse_setting_name ( const char *name,
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struct settings * ( * get_child ) ( struct settings *,
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const char * ),
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struct settings **settings, struct setting *setting ) {
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char tmp_name[ strlen ( name ) + 1 ];
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char *settings_name;
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char *setting_name;
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@ -677,7 +737,7 @@ static int parse_setting_name ( const char *name, struct settings **settings,
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/* Identify settings block, if specified */
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if ( settings_name ) {
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*settings = find_settings ( settings_name );
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*settings = parse_settings_name ( settings_name, get_child );
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if ( *settings == NULL ) {
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DBG ( "Unrecognised settings block \"%s\" in \"%s\"\n",
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settings_name, name );
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@ -731,7 +791,8 @@ int storef_named_setting ( const char *name, const char *value ) {
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struct setting setting;
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int rc;
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if ( ( rc = parse_setting_name ( name, &settings, &setting ) ) != 0 )
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if ( ( rc = parse_setting_name ( name, autovivify_child_settings,
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&settings, &setting ) ) != 0 )
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return rc;
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return storef_setting ( settings, &setting, value );
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}
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@ -749,7 +810,8 @@ int fetchf_named_setting ( const char *name, char *buf, size_t len ) {
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struct setting setting;
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int rc;
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if ( ( rc = parse_setting_name ( name, &settings, &setting ) ) != 0 )
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if ( ( rc = parse_setting_name ( name, find_child_settings,
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&settings, &setting ) ) != 0 )
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return rc;
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return fetchf_setting ( settings, &setting, buf, len );
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}
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@ -193,8 +193,6 @@ extern int fetch_uuid_setting ( struct settings *settings,
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struct setting *setting, union uuid *uuid );
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extern int setting_cmp ( struct setting *a, struct setting *b );
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extern struct settings * find_child_settings ( struct settings *parent,
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const char *name );
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extern struct settings * find_settings ( const char *name );
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extern int storef_setting ( struct settings *settings,
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