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The NIS+ namespace functions are used to locate and manipulate all NIS+ objects except the NIS+ entry objects. See nis_objects(3NSL). To look up the NIS+ entry objects within a NIS+ table, refer to nis_subr(3NSL).
nis_lookup() resolves a NIS+ name and returns a copy of that object from a NIS+ server. nis_add() and nis_remove() add and remove objects to the NIS+ namespace, respectively. nis_modify() can change specific attributes of
an object that already exists in the namespace.
These functions should be used only with names that refer to an NIS+ Directory, NIS+ Table, NIS+ Group, or NIS+ Private object. If a name refers to an NIS+ entry object, the functions listed in nis_subr(3NSL) should be used.
nis_freeresult() frees all memory associated with a nis_result structure. This function must be called to free the memory associated with a NIS+ result. nis_lookup(), nis_add(), nis_remove(), and nis_modify() all return a pointer to a nis_result() structure which must be freed by calling nis_freeresult() when you have finished using it. If one or more of the objects returned in the structure need to be retained, they can be copied with nis_clone_object(3NSL). See nis_subr(3NSL).
nis_lookup() takes two parameters, the name of the object to be resolved in name, and a flags parameter, flags, which is defined below. The object name is expected to correspond to the syntax of a non-indexed NIS+ name . See nis_tables(3NSL). The nis_lookup() function is the only function from this group that can use a non-fully qualified name. If the parameter name
is not a fully qualified name, then the flag EXPAND_NAME must be specified in the call. If this flag is not specified, the function will fail with the error NIS_BADNAME.
The flags parameter is constructed by logically ORing zero or more flags from the following list.
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FOLLOW_LINKS
- When specified, the client library will ``follow'' links by issuing another NIS+ lookup call for the object named by the link. If the linked object is itself a link, then this process will iterate
until the either a object is found that is not a LINK type object, or the library has followed 16 links.
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HARD_LOOKUP
- When specified, the client library will retry the lookup until it is answered by a server. Using this flag will cause the library to block until at least one NIS+ server is available. If the network connectivity
is impaired, this can be a relatively long time.
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NO_CACHE
- When specified, the client library will bypass any object caches and will get the object from either the master NIS+ server or one of its replicas.
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MASTER_ONLY
- When specified, the client library will bypass any object caches and any domain replicas and fetch the object from the NIS+ master server for the object's domain. This insures that the object returned is
up to date at the cost of a possible performance degradation and failure if the master server is unavailable or physically distant.
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EXPAND_NAME
- When specified, the client library will attempt to expand a partially qualified name by calling the function nis_getnames(), which uses the environment variable NIS_PATH. See nis_subr(3NSL).
The status value may be translated to ASCII text using the function nis_sperrno(). See nis_error(3NSL).
On return, the objects array in the result will contain one and possibly several objects that were resolved by the request. If the FOLLOW_LINKS flag was present, on success the function could return several entry objects if the link in
question pointed within a table. If an error occurred when following a link, the objects array will contain a copy of the link object itself.
The function nis_add() will take the object obj and add it to the NIS+ namespace with the name name. This operation will fail if the client making the request does not have the create access right
for the domain in which this object will be added. The parameter name must contain a fully qualified NIS+ name. The object members zo_name and zo_domain will be constructed from this name. This operation will fail if the
object already exists. This feature prevents the accidental addition of objects over another object that has been added by another process.
The function nis_remove() will remove the object with name name from the NIS+ namespace. The client making this request must have the destroy access right for the domain in which this object resides. If the named object is
a link, the link is removed and not the object that it points to. If the parameter obj is not NULL, it is assumed to point to a copy of the object being removed. In this case, if the object on the server does not have
the same object identifier as the object being passed, the operation will fail with the NIS_NOTSAMEOBJ error. This feature allows the client to insure that it is removing the desired object. The parameter name must contain a fully qualified
NIS+ name.
The function nis_modify() will modify the object named by name to the field values in the object pointed to by obj. This object should contain a copy of the object from the name space that is being modified. This operation
will fail with the error NIS_NOTSAMEOBJ if the object identifier of the passed object does not match that of the object being modified in the namespace.
Normally the contents of the member zo_name in the nis_object structure would be constructed from the name passed in the name parameter. However, if it is non-null the client library will use the name in the zo_name member to perform a rename operation on the object. This name must not contain any unquoted `.'(dot) characters. If these conditions are not met the operation will fail and return the NIS_BADNAME error code.
You cannot modify the name of an object if that modification would cause the object to reside in a different domain.
You cannot modify the schema of a table object.
Results
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These functions return a pointer to a structure of type nis_result:
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struct nis_result {
nis_error status;
struct {
uint_t objects_len;
nis_object *objects_val;
} objects;
netobj cookie;
uint32_t zticks;
uint32_t dticks;
uint32_t aticks;
uint32_t cticks;
};
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The status member contains the error status of the the operation. A text message that describes the error can be obtained by calling the function nis_sperrno(). See nis_error(3NSL).
The objects structure contains two members. objects_val is an array of nis_object structures; objects_len is the number of cells in the array. These objects will be freed by the call to nis_freeresult(). If you need to keep a copy of one or more objects, they can be copied with the function nis_clone_object() and freed with the function nis_destroy_object(). See nis_server(3NSL). Refer to nis_objects(3NSL) for a description of the nis_object structure.
The various ticks contain details of where the time was taken during a request. They can be used to tune one's data organization for faster access and to compare different database implementations.
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zticks
- The time spent in the NIS+ service itself. This count starts when the server receives the request and stops when it sends the reply.
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dticks
- The time spent in the database backend. This time is measured from the time a database call starts, until the result is returned. If the request results in multiple calls to the database, this is the sum of all the time spent
in those calls.
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aticks
- The time spent in any ``accelerators'' or caches. This includes the time required to locate the server needed to resolve the request.
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cticks
- The total time spent in the request. This clock starts when you enter the client library and stops when a result is returned. By subtracting the sum of the other ticks values from this value, you can obtain the local overhead
of generating a NIS+ request.
Subtracting the value in dticks from the value in zticks will yield the time spent in the service code itself. Subtracting the sum of the values in zticks and aticks from the
value in cticks will yield the time spent in the client library itself. Note: all of the tick times are measured in microseconds.
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