net-snmp 代理端开发问题记录

来源：互联网发布：sai软件上色编辑：程序博客网时间：2024/05/21 17:27

1.需要在Table中使用rowstatus操作来添加数据，先附上大部分代码

int eocTrapTable_handler(netsnmp_mib_handler* handler,
                              netsnmp_handler_registration* reginfo,
                              netsnmp_agent_request_info* reqinfo,
                              netsnmp_request_info* requests)
{
    netsnmp_request_info *request;
    netsnmp_table_request_info *table_info;
    netsnmp_variable_list *var;
    struct commitInfo *ci = NULL;
    void *data_context = NULL;
    oid *suffix;
    size_t suffix_len;

    suffix = requests->requestvb->name + reginfo->rootoid_len + 1;
    suffix_len = requests->requestvb->name_length - (reginfo->rootoid_len + 1);

    for(request=requests; request; request=request->next)
    {
        var = request->requestvb;
        if(request->processed != 0)
        {
            continue;
        }

        switch(reqinfo->mode)
        {
            case MODE_GET:
                data_context = netsnmp_extract_iterator_context(request);
                if(data_context == NULL)
                {
                    netsnmp_set_request_error(reqinfo, request, SNMP_NOSUCHINSTANCE);
                    continue;
                }
                break;
            case MODE_SET_RESERVE1:
                data_context = netsnmp_extract_iterator_context(request);
                break;
            default:
                ci = netsnmp_oid_stash_get_data(commitStorage, suffix+1, suffix_len-1);
                break;
        }

        table_info = netsnmp_extract_table_info(request);
        if(table_info == NULL)
        {
            continue;
        }

        switch(reqinfo->mode)
        {
            case MODE_GET:
                switch(table_info->colnum)
                {
                    case XXXXXXXXX:
                        break;

case XXXXXXXXX:
break;

                       case XXXXXXXXX:
                        break;
                    default:
                        snmp_log(LOG_ERR, "problem encountered in eocTrapTable_handler: unknown column\n");
                }
                break;

            case MODE_SET_RESERVE1:
                ci = netsnmp_oid_stash_get_data(commitStorage, suffix+1, suffix_len-1);

                if(!ci)
                {
                    ci = (struct commitInfo *)SNMP_MALLOC_STRUCT(commitInfo);
                    if(!data_context)
                    {
                        ci->data_context = eocTrapTable_create_data_context(table_info->indexes, 0);
                        ci->new_row = 1;
                    }
                    else
                    {
                        ci->data_context = data_context;
                    }
                    netsnmp_oid_stash_add_data(&commitStorage, suffix+1, suffix_len-1, ci);
                }
                break;

            case MODE_SET_RESERVE2:
                 /********************/
                break;

            case MODE_SET_ACTION:
                switch(table_info->colnum)
                {

                    case COLUMN_EOCTRAPIP:

                          /********************/
                        break;
                    case COLUMN_EOCTRAPCOMMUNITY:
                       /********************/
                        break;
                    case COLUMN_EOCTRAPSTATUS:
                      /********************/
                        break;
                    case COLUMN_EOCTRAPROWSTATUS:
                        {
                            int ret;
                            ret = set_eocTrapRowStatus(ci->data_context,
                                                       (long *)request->requestvb->val.string,
                                                       request->requestvb->val_len);
                            if(ret)
                            {
                                netsnmp_set_request_error(reqinfo, request, ret);
                            }

                            if(*request->requestvb->val.integer == RS_DESTROY)
                            {
                                ci->new_row = -1;
                            }
                        }
                        break;
                 }
                break;

            case MODE_SET_COMMIT:
                if(!ci->have_committed)
                {
                    eocTrapTable_commit_row(&ci->data_context, ci->new_row);
                    ci->have_committed = 1;
                }
                break;

            case MODE_SET_UNDO:
                switch(table_info->colnum)
                {
                    case COLUMN_EOCTRAPIP:
                        {
                            int retval;
                            struct undoInfo *ui;

                            ui = netsnmp_oid_stash_get_data(undoStorage, suffix, suffix_len);

                            retval = set_eocTrapIP(ci->data_context, ui->ptr, ui->len);
                            if(retval)
                            {
                                netsnmp_set_request_error(reqinfo, request, SNMP_ERR_UNDOFAILED);
                            }
                        }
                        break;
                    case COLUMN_EOCTRAPROWSTATUS:
                        {
                            int retval;
                            struct undoInfo *ui;

                            ui = netsnmp_oid_stash_get_data(undoStorage, suffix, suffix_len);

                            retval = set_eocTrapRowStatus(ci->data_context, ui->ptr, ui->len);
                            if(retval)
                            {
                                netsnmp_set_request_error(reqinfo, request, SNMP_ERR_UNDOFAILED);
                            }
                        }
                        break;
                    case COLUMN_EOCTRAPCOMMUNITY:
                    case COLUMN_EOCTRAPSTATUS:
                        break;
                }
                break;

            case MODE_SET_FREE:
                break;

            default:
                snmp_log(LOG_ERR, "problem encountered in eocTrapTable_handler: unsupported mode\n");
        }
    }

    switch(reqinfo->mode)
    {
        case MODE_SET_UNDO:
        case MODE_SET_FREE:
        case MODE_SET_COMMIT:
            netsnmp_oid_stash_free(&undoStorage, eocTrapGroup_free_undoInfo);
            netsnmp_oid_stash_free(&commitStorage, netsnmp_oid_stash_no_free);
            break;
    }

    return SNMP_ERR_NOERROR;
}

int set_eocTrapRowStatus(void* data_context, long* val, size_t val_len)
{
    struct eocTrapTable_entry *entry = (struct eocTrapTable_entry*)data_context;
     printf("BBBBBBB\n");
   printf("index=%d\n",entry->index);
   printf("len=%ld\n",val_len);
   printf("lval=%ld\n",*val);
    memcpy(&entry->rowStatus, val, val_len);
   printf("CCCCCCC\n");
   printf("rowStatus==%d\n",entry->rowStatus);
    return SNMP_ERR_NOERROR;
}

void* eocTrapTable_create_data_context(netsnmp_variable_list* index_data, int column)
{
   struct eocTrapTable_entry *entry = NULL;

   entry = (struct eocTrapTable_entry *)SNMP_MALLOC_STRUCT(eocTrapTable_entry);
   if(!entry)
   {
           snmp_log(LOG_ERR,"%s:%d\n", __FUNCTION__,__LINE__);
           return;
   }
   memset(entry, 0, sizeof(struct eocTrapTable_entry));

   entry->index = *(index_data->val.integer);

   entry->next = g_eocTrapTable_head;
   g_eocTrapTable_head = entry;

   return entry;

}

本人刚接触snmp不久，在对于给一个空表添加数据的问题很是烦恼，因为在mibbrowser工具中空表是选不到表变量来直行set操作，然后我在工具加载好的mib库中选中某个节点和rowstatus一起set ，会返回设置失败，原因是没有加上索引，那么问题来了既然是空表，又哪来的索引，所以在set的时候，要对set的的oid加上索引，才能执行set操作。这一步走过了，但是我发现我的程序snmpd 在执行set的时候发生了段错误，我找来找去结果发现，段错误出现在set_eocTrapRowStatus中只要一使用entry->index就段错误只打印出BBBBBBB，我发现这个entry等于NULL ，使用指针才发生段错误。我就往上面的代码找，经过不懈努力原来的代码中case MODE_SET_RESERVE1:中执行的eocTrapTable_create_data_context(table_info->indexes, 0);这个函数是一个假函数是直接return NULL；问题就在这里之后我仿写了这个函数创建了表项之后执行上述空表添加就ok了。

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