/**
* This function injects a "read only" handler into the handler chain
* prior to serializing/registering the handler.
*
* The only purpose of this "read only" handler is to return an
* appropriate error for any requests passed to it in a SET mode.
* Inserting it into your handler chain will ensure you're never
* asked to perform a SET request so you can ignore those error
* conditions.
*
* @param reginfo a handler registration structure which could get created
* using netsnmp_create_handler_registration. Used to register
* a read only instance helper handler.
*
* @return
* MIB_REGISTERED_OK is returned if the registration was a success.
* Failures are MIB_REGISTRATION_FAILED and MIB_DUPLICATE_REGISTRATION.
*/
int
netsnmp_register_read_only_instance(netsnmp_handler_registration *reginfo)
{
netsnmp_inject_handler(reginfo, netsnmp_get_instance_handler());
netsnmp_inject_handler(reginfo, netsnmp_get_read_only_handler());
return netsnmp_register_serialize(reginfo);
}
/** registers a handler as a read-only data table
* If table_info != NULL, it registers it as a normal table too. */
int
netsnmp_register_read_only_table_data(netsnmp_handler_registration *reginfo,
netsnmp_table_data *table,
netsnmp_table_registration_info *table_info)
{
netsnmp_inject_handler(reginfo, netsnmp_get_read_only_handler());
return netsnmp_register_table_data(reginfo, table, table_info);
}
int
netsnmp_register_read_only_scalar(netsnmp_handler_registration *reginfo)
{
/*
* Extend the registered OID with space for the instance subid
* (but don't extend the length just yet!)
*/
reginfo->rootoid = realloc(reginfo->rootoid,
(reginfo->rootoid_len+1) * sizeof(oid) );
reginfo->rootoid[ reginfo->rootoid_len ] = 0;
netsnmp_inject_handler(reginfo, netsnmp_get_instance_handler());
netsnmp_inject_handler(reginfo, netsnmp_get_scalar_handler());
netsnmp_inject_handler(reginfo, netsnmp_get_read_only_handler());
return netsnmp_register_serialize(reginfo);
}
/**
* This function injects a "read only" handler into the handler chain
* prior to serializing/registering the handler.
*
* The only purpose of this "read only" handler is to return an
* appropriate error for any requests passed to it in a SET mode.
* Inserting it into your handler chain will ensure you're never
* asked to perform a SET request so you can ignore those error
* conditions.
*
* @param reginfo a handler registration structure which could get created
* using netsnmp_create_handler_registration. Used to register
* a read only instance helper handler.
*
* @return
* MIB_REGISTERED_OK is returned if the registration was a success.
* Failures are MIB_REGISTRATION_FAILED and MIB_DUPLICATE_REGISTRATION.
*/
int
netsnmp_register_read_only_instance(netsnmp_handler_registration *reginfo)
{
netsnmp_mib_handler *h1, *h2;
if (!reginfo)
return MIB_REGISTRATION_FAILED;
h1 = netsnmp_get_instance_handler();
h2 = netsnmp_get_read_only_handler();
if (h1 && h2 && netsnmp_inject_handler(reginfo, h1) == SNMPERR_SUCCESS) {
h1 = NULL;
if (netsnmp_inject_handler(reginfo, h2) == SNMPERR_SUCCESS)
return netsnmp_register_serialize(reginfo);
}
snmp_log(LOG_ERR, "failed to register read only instance\n");
netsnmp_handler_free(h1);
netsnmp_handler_free(h2);
netsnmp_handler_registration_free(reginfo);
return MIB_REGISTRATION_FAILED;
}
/** initializes the read_only helper which then registers a read_only
* handler as a run-time injectable handler for configuration file
* use.
*/
void
netsnmp_init_read_only_helper(void)
{
netsnmp_register_handler_by_name("read_only",
netsnmp_get_read_only_handler());
}
