Multiple-Attribute Operations

fn_attr_get_ids
fn_attr_multiget
fn_multigetlist_next
fn_multigetlist_destroy
fn_attr_multi_modify

These operations allow the caller to specify an operation that handles on multiple attributes using one or more calls.

The failure semantics can vary widely across naming systems. In some systems the single function call can contain multiple individual naming system operations, with no guarantees of atomicity.

Get Attribute Identifiers

This operation gets a list of all the attribute identifiers that are associated with the object named name relative to the context ctx. If name is empty, the attribute identifiers associated with ctx are returned.

FN_attrset_t *fn_attr_get_ids(
    FN_ctx_t *ctx,
    const   FN_composite_name_t *name,
    unsigned int follow_link,
    FN_status_t *status);

Get Multiple Attributes

Get one or more attributes associated with the object named name relative to the context ctx. If name is empty, the attributes associated with ctx are returned.

FN_multigetlist_t *fn_attr_multiget(
    FN_ctx_t *ctx,
    const   FN_composite_name_t *name,
    const   FN_attrset_t *attr_ids,
    unsigned int follow_link,
    FN_status_t *status);
 
    FN_attribute_t *fn_multigetlist_next(
    FN_multigetlist_t *ml,
    FN_status_t *status);
 
void fn_multigetlist_destroy(   
    FN_multigetlist_t *ml);

The attributes returned are those specified in attr_ids. If the value of attr_ids is 0, all attributes associated with the named object are returned. Any attribute values in attr_ids provided by the caller are ignored; only the identifiers are relevant for this operation. Each attribute (identifier, syntax, and values) is returned one at a time using an enumeration scheme similar to that for listing a context. fn_attr_multi_get() initiates the enumeration process. It returns a handle to an FN_multigetlist_t object that can be used for subsequent fn_multigetlist_next() calls to enumerate the attributes requested.

The operation fn_multigetlist_next() returns the next attribute (identifier, syntax, and values) in the enumeration and updates ml to indicate the state of the enumeration. Successive calls to fn_multigetlist_next() using ml return successive attributes in the enumeration and further update the state of the enumeration.

The operation fn_multigetlist_destroy() frees the resources used during the enumeration. This operation can be invoked at any time to terminate the enumeration.

Implementations are not required to return all attributes requested by attr_ids. Some might choose to return only the attributes found successfully; such implementations might not necessarily return identifiers for attributes that could not be read.

Modify Multiple Attributes

Modify the attributes associated with the object named name, relative to ctx.

int fn_attr_multi_modify(
    FN_ctx_t *ctx,
    const   FN_composite_name_t *name,
    const   FN_attrmodlist_t *mods,
    unsigned int follow_link,                                  
    FN_attrmodlist_t **unexecuted_mods,
    FN_status_t *status);

In the mods parameter, the caller specifies a sequence of modifications that are to be performed in order on the attributes. Each modification in the sequence specifies a modification operation code (shown in Table 2-1) and an attribute on which to operate.

If all the modifications were performed successfully, unexecuted_mods is a NULL pointer. If an error is encountered while performing the list of modifications, status indicates the type of error and unexecuted_mods is set to point to a list of unexecuted modifications. The contents of unexecuted_mods do not share any state with mods; items in unexecuted_mods are copies of items in mods and appear in the same order in which they were originally supplied in mods. The first operation in unexecuted_mods is the first one that failed, and the code in status applies to this modification operation in particular. If status indicates a failure and a NULL pointer is returned in unexecuted_mods, that means no modifications were executed.