Re: how to get table data inside request handler

I have found an answer on my question: I should keep table_set variable
(result of netsnmp_create_table_data_set()) to access them in Watcher
handler. (Watcher() is a handler of SNMP requests like GET, SET)

But now I have a strange situation:

1. My table has one row (named "ROW1", for example)

2. I receive snmpwalk request

3. Watcher() is called: here I delete all rows which I can

  netsnmp_table_row* row = netsnmp_table_data_set_get_first_row(table_set);
  while(row)
  {
  netsnmp_table_dataset_remove_and_delete_row(table_set,row);
  row = netsnmp_table_data_set_get_next_row(table_set,row);
  fprintf(stderr,"DELETED NEW ROW\n");
  }

4. snmpwalk returns "ROW1" - how is it possible if I deleted all rows in
Watcher()? And how to delete them in right way?

Actually, second snmpwalk call shows there are no any rows. I.e. I delete
all rows for next snmpwalk, but not current one.

Can you please help to find out a way to update the table when I receive GET
requests?

Thanks in advance.
2009/2/18 Alexander Bubnov <[email protected]>

> requests varibale of Watcher keeps row instead table pointer
>
> netsnmp_extract_table_data_set(requests); returns NULL
>
> netsnmp_extract_table_row(requests); returns valid data of row.
>
> What should I do to put table data inside request or how to get table data
> by row?
>
> 2009/2/18 Alexander Bubnov <[email protected]>
>
>> Hello, all!
>>
>> Can you please let me know a way getting table data to manipulate it?
>>
>> below code:
>>
>> 1. init_tables - init tables within main function.
>>
>> 2. Watcher - a callback, it is called when some request is received.
>> Inside of this callback I would like to change the table content before I
>> need to get a pointer to the table.
>>
>> inside Watcher() netsnmp_extract_table_data_set() function get NULL
>> instead returing data.
>>
>> #include<string.h>
>> #include <net-snmp/net-snmp-config.h>
>> #include <net-snmp/net-snmp-includes.h>
>> #include <net-snmp/agent/net-snmp-agent-includes.h>
>>
>> const int ROWID = 2;
>>
>>
>> static int Watcher(
>>   netsnmp_mib_handler * handler
>>   ,netsnmp_handler_registration * reginfo
>>   ,netsnmp_agent_request_info * reqinfo
>>   ,netsnmp_request_info * requests
>>   )
>> {
>>
>>   if(MODE_IS_GET(reqinfo->mode))
>>   {
>>   netsnmp_request_info *request;
>>   int i = 0;
>>
>>   for(request=requests;request;request = request->next)
>>   {
>>   netsnmp_table_data_set*table_set =
>> netsnmp_extract_table_data_set(requests);
>>
>>   if(table_set)
>>   {
>>   fprintf(stderr,"NOT NULL\n");
>>
>>   }
>>   else
>>   {
>>   fprintf(stderr,"NULL\n");
>>   }
>>   }
>>
>>   return SNMP_ERR_NOERROR;
>>   }
>>   else if(MODE_IS_SET(reqinfo->mode))
>>   {
>>   puts("SET request is is not allowed");
>>   return SNMP_ERR_NOTWRITABLE;
>>   }
>>   return SNMP_ERR_GENERR;
>> }
>>
>>
>> void init_tables()
>> {
>>   netsnmp_table_data_set *table_set;
>>   oid some_oid[] = {1,3,6,1,4,1,23668,1025,2,8,1};
>>   const char * table_name = "mytable";
>>
>>   const size_t size_some_oid = OID_LENGTH(some_oid);
>>   int count = 999;
>>   const char* pcount = (const char*)(&count);
>>
>>   table_set = netsnmp_create_table_data_set(table_name);
>>
>>   table_set->allow_creation = 0;
>>
>>   netsnmp_table_dataset_add_index(table_set, ASN_OCTET_STR);
>>
>>   netsnmp_table_set_multi_add_default_row(table_set,
>>   /*
>>   * column 2 = asn type,
>>   * writable = 0,
>>   * default value = NULL,
>>   * default value len = 0
>>   */
>>   ROWID,ASN_COUNTER,0,NULL,0,
>>   NULL /* done */ );
>>
>>   netsnmp_register_table_data_set(netsnmp_create_handler_registration
>>   (table_name, Watcher,
>>   some_oid,
>>   size_some_oid,
>>   HANDLER_CAN_RONLY|HANDLER_CAN_NOT_CREATE), table_set, NULL);
>>
>>   netsnmp_table_row *row = netsnmp_create_table_data_row();
>>   netsnmp_table_row_add_index(row, ASN_OCTET_STR, "some data string",
>>   strlen("some data string"));
>>   netsnmp_set_row_column(row, ROWID, ASN_COUNTER,
>>   pcount, sizeof(int));
>>   netsnmp_mark_row_column_writable(row, ROWID, 0);
>>   netsnmp_table_dataset_add_row(table_set, row);
>> }
>>
>>
>>
>> --
>> /BR, Alexander
>>
>
>
>
> --
> /BR, Alexander
>



-- 
/BR, Alexander

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