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[settings] Provide fetch_setting_origin() 

Inspired-by: Glenn Brown <glenn@myri.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
This commit is contained in:
Michael Brown 2011-03-22 17:41:47 +00:00
parent f732fa28c8
commit ba8dd80487
2 changed files with 49 additions and 5 deletions
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52
src/core/settings.c
View File

@ -552,10 +552,11 @@ int store_setting ( struct settings *settings, struct setting *setting,
}
/**
* Fetch value of setting
* Fetch value and origin of setting
*
* @v settings Settings block, or NULL to search all blocks
* @v setting Setting to fetch
* @v origin Origin of setting to fill in
* @v data Buffer to fill with setting data
* @v len Length of buffer
* @ret len Length of setting data, or negative error
@ -563,13 +564,17 @@ int store_setting ( struct settings *settings, struct setting *setting,
* The actual length of the setting will be returned even if
* the buffer was too small.
*/
int fetch_setting ( struct settings *settings, struct setting *setting,
void *data, size_t len ) {
static int fetch_setting_and_origin ( struct settings *settings,
struct setting *setting,
struct settings **origin,
void *data, size_t len ) {
struct settings *child;
int ret;
/* Avoid returning uninitialised data on error */
memset ( data, 0, len );
if ( origin )
*origin = NULL;
/* NULL settings implies starting at the global settings root */
if ( ! settings )
@ -583,19 +588,56 @@ int fetch_setting ( struct settings *settings, struct setting *setting,
if ( setting_applies ( settings, setting ) &&
( ( ret = settings->op->fetch ( settings, setting,
data, len ) ) >= 0 ) ) {
if ( origin )
*origin = settings;
return ret;
}
/* Recurse into each child block in turn */
list_for_each_entry ( child, &settings->children, siblings ) {
if ( ( ret = fetch_setting ( child, setting,
data, len ) ) >= 0 )
if ( ( ret = fetch_setting_and_origin ( child, setting, origin,
data, len ) ) >= 0 )
return ret;
}
return -ENOENT;
}
/**
* Fetch value of setting
*
* @v settings Settings block, or NULL to search all blocks
* @v setting Setting to fetch
* @v data Buffer to fill with setting data
* @v len Length of buffer
* @ret len Length of setting data, or negative error
*
* The actual length of the setting will be returned even if
* the buffer was too small.
*/
int fetch_setting ( struct settings *settings, struct setting *setting,
void *data, size_t len ) {
return fetch_setting_and_origin ( settings, setting, NULL, data, len );
}
/**
* Fetch origin of setting
*
* @v settings Settings block, or NULL to search all blocks
* @v setting Setting to fetch
* @ret origin Origin of setting, or NULL if not found
*
* This function can also be used as an existence check for the
* setting.
*/
struct settings * fetch_setting_origin ( struct settings *settings,
struct setting *setting ) {
struct settings *origin;
fetch_setting_and_origin ( settings, setting, &origin, NULL, 0 );
return origin;
}
/**
* Fetch length of setting
*

2
src/include/ipxe/settings.h
View File

@ -217,6 +217,8 @@ extern int store_setting ( struct settings *settings, struct setting *setting,
const void *data, size_t len );
extern int fetch_setting ( struct settings *settings, struct setting *setting,
void *data, size_t len );
extern struct settings * fetch_setting_origin ( struct settings *settings,
struct setting *setting );
extern int fetch_setting_len ( struct settings *settings,
struct setting *setting );
extern int fetch_string_setting ( struct settings *settings,