table_array.c

snmp的源代码,已经在我的ubuntu下编译通过

/*
 * table_array.c
 * $Id: table_array.c,v 5.23.2.1 2004/12/10 03:39:39 rstory Exp $
 */

#include <net-snmp/net-snmp-config.h>

#if HAVE_STRING_H
#include <string.h>
#else
#include <strings.h>
#endif

#include <net-snmp/net-snmp-includes.h>
#include <net-snmp/agent/net-snmp-agent-includes.h>

#include <net-snmp/agent/table.h>
#include <net-snmp/agent/table_array.h>
#include <net-snmp/library/container.h>
#include <net-snmp/library/snmp_assert.h>

#if HAVE_DMALLOC_H
#include <dmalloc.h>
#endif

/*
 * snmp.h:#define SNMP_MSG_INTERNAL_SET_BEGIN        -1 
 * snmp.h:#define SNMP_MSG_INTERNAL_SET_RESERVE1     0 
 * snmp.h:#define SNMP_MSG_INTERNAL_SET_RESERVE2     1 
 * snmp.h:#define SNMP_MSG_INTERNAL_SET_ACTION       2 
 * snmp.h:#define SNMP_MSG_INTERNAL_SET_COMMIT       3 
 * snmp.h:#define SNMP_MSG_INTERNAL_SET_FREE         4 
 * snmp.h:#define SNMP_MSG_INTERNAL_SET_UNDO         5 
 */

static const char *mode_name[] = {
    "Reserve 1",
    "Reserve 2",
    "Action",
    "Commit",
    "Free",
    "Undo"
};

/*
 * PRIVATE structure for holding important info for each table.
 */
typedef struct table_container_data_s {

   /** registration info for the table */
    netsnmp_table_registration_info *tblreg_info;

   /** container for the table rows */
   netsnmp_container          *table;

    /*
     * mutex_type                lock;
     */

   /** do we want to group rows with the same index
    * together when calling callbacks? */
    int             group_rows;

   /** callbacks for this table */
    netsnmp_table_array_callbacks *cb;

} table_container_data;

/** @defgroup table_array table_array: Helps you implement a table when data can be stored locally. The data is stored in a sorted array, using a binary search for lookups.
 *  @ingroup table
 *
 *  The table_array handler is used (automatically) in conjuntion
 *  with the @link table table@endlink handler. It is primarily
 *  intended to be used with the mib2c configuration file
 *  mib2c.array-user.conf.
 *
 *  The code generated by mib2c is useful when you have control of
 *  the data for each row. If you cannot control when rows are added
 *  and deleted (or at least be notified of changes to row data),
 *  then this handler is probably not for you.
 *
 *  This handler makes use of callbacks (function pointers) to
 *  handle various tasks. Code is generated for each callback,
 *  but will need to be reviewed and flushed out by the user.
 *
 *  NOTE NOTE NOTE: Once place where mib2c is somewhat lacking
 *  is with regards to tables with external indices. If your
 *  table makes use of one or more external indices, please
 *  review the generated code very carefully for comments
 *  regarding external indices.
 *
 *  NOTE NOTE NOTE: This helper, the API and callbacks are still
 *  being tested and may change.
 *
 *  The generated code will define a structure for storage of table
 *  related data. This structure must be used, as it contains the index
 *  OID for the row, which is used for keeping the array sorted. You can
 *  add addition fields or data to the structure for your own use.
 *
 *  The generated code will also have code to handle SNMP-SET processing.
 *  If your table does not support any SET operations, simply comment
 *  out the #define <PREFIX>_SET_HANDLING (where <PREFIX> is your
 *  table name) in the header file.
 *
 *  SET processing modifies the row in-place. The duplicate_row
 *  callback will be called to save a copy of the original row.
 *  In the event of a failure before the commite phase, the
 *  row_copy callback will be called to restore the original row
 *  from the copy.
 *
 *  Code will be generated to handle row creation. This code may be
 *  disabled by commenting out the #define <PREFIX>_ROW_CREATION
 *  in the header file.
 *
 *  If your table contains a RowStatus object, by default the
 *  code will not allow object in an active row to be modified.
 *  To allow active rows to be modified, remove the comment block
 *  around the #define <PREFIX>_CAN_MODIFY_ACTIVE_ROW in the header
 *  file.
 *
 *  Code will be generated to maintain a secondary index for all
 *  rows, stored in a binary tree. This is very useful for finding
 *  rows by a key other than the OID index. By default, the functions
 *  for maintaining this tree will be based on a character string.
 *  NOTE: this will likely be made into a more generic mechanism,
 *  using new callback methods, in the near future.
 *
 *  The generated code contains many TODO comments. Make sure you
 *  check each one to see if it applies to your code. Examples include
 *  checking indices for syntax (ranges, etc), initializing default
 *  values in newly created rows, checking for row activation and
 *  deactivation requirements, etc.
 *
 * @{
 */

/**********************************************************************
 **********************************************************************
 *                                                                    *
 *                                                                    *
 * PUBLIC Registration functions                                      *
 *                                                                    *
 *                                                                    *
 **********************************************************************
 **********************************************************************/
/** register specified callbacks for the specified table/oid. If the
    group_rows parameter is set, the row related callbacks will be
    called once for each unique row index. Otherwise, each callback
    will be called only once, for all objects.
*/
int
netsnmp_table_container_register(netsnmp_handler_registration *reginfo,
                             netsnmp_table_registration_info *tabreg,
                             netsnmp_table_array_callbacks *cb,
                             netsnmp_container *container,
                             int group_rows)
{
    table_container_data *tad = SNMP_MALLOC_TYPEDEF(table_container_data);
    if (!tad)
        return SNMPERR_GENERR;
    tad->tblreg_info = tabreg;  /* we need it too, but it really is not ours */

    if (!cb) {
        snmp_log(LOG_ERR, "table_array registration with no callbacks\n" );
        return SNMPERR_GENERR;
    }
    /*
     * check for required callbacks
     */
    if ((cb->can_set &&
         ((NULL==cb->duplicate_row) || (NULL==cb->delete_row) ||
          (NULL==cb->row_copy)) )) {
        snmp_log(LOG_ERR, "table_array registration with incomplete "
                 "callback structure.\n");
        return SNMPERR_GENERR;
    }

    if (NULL==container)
        tad->table = netsnmp_container_find("table_array");
    else
        tad->table = container;
    if (NULL==container->compare)
        container->compare = netsnmp_compare_netsnmp_index;
    if (NULL==container->ncompare)
        container->ncompare = netsnmp_ncompare_netsnmp_index;
    
    tad->cb = cb;

    reginfo->handler->myvoid = tad;

    return netsnmp_register_table(reginfo, tabreg);
}

/** find the handler for the table_array helper. */
netsnmp_mib_handler *
netsnmp_find_table_array_handler(netsnmp_handler_registration *reginfo)
{
    netsnmp_mib_handler *mh;
    if (!reginfo)
        return NULL;
    mh = reginfo->handler;
    while (mh) {
        if (mh->access_method == netsnmp_table_array_helper_handler)
            break;
        mh = mh->next;
    }

    return mh;
}

/** find the context data used by the table_array helper */
netsnmp_container      *
netsnmp_extract_array_context(netsnmp_request_info *request)
{
    return netsnmp_request_get_list_data(request, TABLE_ARRAY_NAME);
}

/** this function is called to validate RowStatus transitions. */
int
netsnmp_table_array_check_row_status(netsnmp_table_array_callbacks *cb,
                                     netsnmp_request_group *ag,
                                     long *rs_new, long *rs_old)
{
    netsnmp_index *row_ctx;
    netsnmp_index *undo_ctx;
    if (!ag || !cb)
        return SNMPERR_GENERR;
    row_ctx  = ag->existing_row;
    undo_ctx = ag->undo_info;
    
    /*
     * xxx-rks: revisit row delete scenario
     */
    if (row_ctx) {
        /*
         * either a new row, or change to old row
         */
        /*
         * is it set to active?
         */
        if (RS_IS_GOING_ACTIVE(*rs_new)) {
            /*
             * is it ready to be active?
             */
            if ((NULL==cb->can_activate) ||
                cb->can_activate(undo_ctx, row_ctx, ag))
                *rs_new = RS_ACTIVE;
            else
                return SNMP_ERR_INCONSISTENTVALUE;
        } else {
            /*
             * not going active
             */
            if (undo_ctx) {
                /*
                 * change
                 */
                if (RS_IS_ACTIVE(*rs_old)) {
                    /*
                     * check pre-reqs for deactivation
                     */
                    if (cb->can_deactivate &&
                        !cb->can_deactivate(undo_ctx, row_ctx, ag)) {
                        return SNMP_ERR_INCONSISTENTVALUE;
                    }
                }
            } else {
                /*
                 * new row
                 */
            }

            if (*rs_new != RS_DESTROY) {
                if ((NULL==cb->can_activate) ||
                    cb->can_activate(undo_ctx, row_ctx, ag))
                    *rs_new = RS_NOTINSERVICE;
                else
                    *rs_new = RS_NOTREADY;
            } else {
                if (cb->can_delete && !cb->can_delete(undo_ctx, row_ctx, ag)) {
                    return SNMP_ERR_INCONSISTENTVALUE;
                }
                ag->row_deleted = 1;
            }
        }
    } else {
        /*
         * check pre-reqs for delete row
         */
        if (cb->can_delete && !cb->can_delete(undo_ctx, row_ctx, ag)) {
            return SNMP_ERR_INCONSISTENTVALUE;
        }