table_dataset.c

开发snmp的开发包有两个开放的SNMP开发库

#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>

static netsnmp_data_list *auto_tables;

typedef struct data_set_tables_s {
    netsnmp_table_data_set *table_set;
} data_set_tables;

typedef struct data_set_cache_s {
    void           *data;
    size_t          data_len;
} data_set_cache;

#define STATE_ACTION   1
#define STATE_COMMIT   2
#define STATE_UNDO     3
#define STATE_FREE     4

typedef struct newrow_stash_s {
    netsnmp_table_row *newrow;
    int             state;
    int             created;
    int             deleted;
} newrow_stash;

/** @defgroup table_dataset table_dataset
 *  Helps you implement a table with automatted storage.
 *  @ingroup table_data
 *
 *  This helper is obsolete.  If you are writing a new module, please
 *  consider using the table_dataset2 helper instead.
 *
 *  This handler helps you implement a table where all the data is
 *  expected to be stored within the agent itself and not in some
 *  external storage location.  It handles all MIB requests including
 *  GETs, GETNEXTs and SETs.  It's possible to simply create a table
 *  without actually ever defining a handler to be called when SNMP
 *  requests come in.  To use the data, you can either attach a
 *  sub-handler that merely uses/manipulates the data further when
 *  requests come in, or you can loop through it externally when it's
 *  actually needed.  This handler is most useful in cases where a
 *  table is holding configuration data for something which gets
 *  triggered via another event.
 *
 *  NOTE NOTE NOTE: This helper isn't complete and is likely to change
 *  somewhat over time.  Specifically, the way it stores data
 *  internally may change drastically.
 *  
 *  @{
 */

void
netsnmp_init_table_dataset(void) {
#ifndef NETSNMP_DISABLE_MIB_LOADING
    register_app_config_handler("table",
                                netsnmp_config_parse_table_set, NULL,
                                "tableoid");
#endif /* NETSNMP_DISABLE_MIB_LOADING */
    register_app_config_handler("add_row", netsnmp_config_parse_add_row,
                                NULL, "table_name indexes... values...");
}

/* ==================================
 *
 * Data Set API: Table maintenance
 *
 * ================================== */

/** Create a netsnmp_table_data_set structure given a table_data definition */
netsnmp_table_data_set *
netsnmp_create_table_data_set(const char *table_name)
{
    netsnmp_table_data_set *table_set =
        SNMP_MALLOC_TYPEDEF(netsnmp_table_data_set);
    if (!table_set)
        return NULL;
    table_set->table = netsnmp_create_table_data(table_name);
    return table_set;
}

/** clones a dataset row, including all data. */
netsnmp_table_row *
netsnmp_table_data_set_clone_row(netsnmp_table_row *row)
{
    netsnmp_table_data_set_storage *data, **newrowdata;
    netsnmp_table_row *newrow;

    if (!row)
        return NULL;

    newrow = netsnmp_table_data_clone_row(row);
    if (!newrow)
        return NULL;

    data = (netsnmp_table_data_set_storage *) row->data;

    if (data) {
        for (newrowdata =
             (netsnmp_table_data_set_storage **) &(newrow->data); data;
             newrowdata = &((*newrowdata)->next), data = data->next) {

            memdup((u_char **) newrowdata, (u_char *) data,
                   sizeof(netsnmp_table_data_set_storage));
            if (!*newrowdata) {
                netsnmp_table_dataset_delete_row(newrow);
                return NULL;
            }

            if (data->data.voidp) {
                memdup((u_char **) & ((*newrowdata)->data.voidp),
                       (u_char *) data->data.voidp, data->data_len);
                if (!(*newrowdata)->data.voidp) {
                    netsnmp_table_dataset_delete_row(newrow);
                    return NULL;
                }
            }
        }
    }
    return newrow;
}

/** deletes a single dataset table data.
 *  returns the (possibly still good) next pointer of the deleted data object.
 */
NETSNMP_INLINE netsnmp_table_data_set_storage *
netsnmp_table_dataset_delete_data(netsnmp_table_data_set_storage *data)
{
    netsnmp_table_data_set_storage *nextPtr = NULL;
    if (data) {
        nextPtr = data->next;
        SNMP_FREE(data->data.voidp);
    }
    SNMP_FREE(data);
    return nextPtr;
}

/** deletes all the data from this node and beyond in the linked list */
NETSNMP_INLINE void
netsnmp_table_dataset_delete_all_data(netsnmp_table_data_set_storage *data)
{

    while (data) {
        data = netsnmp_table_dataset_delete_data(data);
    }
}

/** deletes all the data from this node and beyond in the linked list */
NETSNMP_INLINE void
netsnmp_table_dataset_delete_row(netsnmp_table_row *row)
{
    netsnmp_table_data_set_storage *data;

    if (!row)
        return;

    data = netsnmp_table_data_delete_row(row);
    netsnmp_table_dataset_delete_all_data(data);
}

/** adds a new row to a dataset table */
NETSNMP_INLINE void
netsnmp_table_dataset_add_row(netsnmp_table_data_set *table,
                              netsnmp_table_row *row)
{
    if (!table)
        return;
    netsnmp_table_data_add_row(table->table, row);
}

/** adds a new row to a dataset table */
NETSNMP_INLINE void
netsnmp_table_dataset_replace_row(netsnmp_table_data_set *table,
                                  netsnmp_table_row *origrow,
                                  netsnmp_table_row *newrow)
{
    if (!table)
        return;
    netsnmp_table_data_replace_row(table->table, origrow, newrow);
}

/** removes a row from the table, but doesn't delete/free the column values */
NETSNMP_INLINE void
netsnmp_table_dataset_remove_row(netsnmp_table_data_set *table,
                                 netsnmp_table_row *row)
{
    if (!table)
        return;

    netsnmp_table_data_remove_and_delete_row(table->table, row);
}

/** removes a row from the table and then deletes it (and all its data) */
NETSNMP_INLINE void
netsnmp_table_dataset_remove_and_delete_row(netsnmp_table_data_set *table,
                                            netsnmp_table_row *row)
{
    netsnmp_table_data_set_storage *data;

    if (!table)
        return;

    data = (netsnmp_table_data_set_storage *)
        netsnmp_table_data_remove_and_delete_row(table->table, row);

    netsnmp_table_dataset_delete_all_data(data);
}

/* ==================================
 *
 * Data Set API: Default row operations
 *
 * ================================== */

/** creates a new row from an existing defined default set */
netsnmp_table_row *
netsnmp_table_data_set_create_row_from_defaults
    (netsnmp_table_data_set_storage *defrow)
{
    netsnmp_table_row *row;
    row = netsnmp_create_table_data_row();
    if (!row)
        return NULL;
    for (; defrow; defrow = defrow->next) {
        netsnmp_set_row_column(row, defrow->column, defrow->type,
                               defrow->data.voidp, defrow->data_len);
        if (defrow->writable)
            netsnmp_mark_row_column_writable(row, defrow->column, 1);

    }
    return row;
}

/** adds a new default row to a table_set.
 * Arguments should be the table_set, column number, variable type and
 * finally a 1 if it is allowed to be writable, or a 0 if not.  If the
 * default_value field is not NULL, it will be used to populate new
 * valuse in that column fro newly created rows. It is copied into the
 * storage template (free your calling argument).
 *
 * returns SNMPERR_SUCCESS or SNMPERR_FAILURE
 */
int
netsnmp_table_set_add_default_row(netsnmp_table_data_set *table_set,
                                  unsigned int column,
                                  int type, int writable,
                                  void *default_value,
                                  size_t default_value_len)
{
    netsnmp_table_data_set_storage *new_col, *ptr, *pptr;

    if (!table_set)
        return SNMPERR_GENERR;

    /*
     * double check 
     */
    new_col =
        netsnmp_table_data_set_find_column(table_set->default_row, column);
    if (new_col != NULL) {
        if (new_col->type == type && new_col->writable == writable)
            return SNMPERR_SUCCESS;
        return SNMPERR_GENERR;
    }

    new_col = SNMP_MALLOC_TYPEDEF(netsnmp_table_data_set_storage);
    new_col->type = type;
    new_col->writable = writable;
    new_col->column = column;
    if (default_value) {
        memdup((u_char **) & (new_col->data.voidp),
               (u_char *) default_value, default_value_len);
        new_col->data_len = default_value_len;
    }
    if (table_set->default_row == NULL)
        table_set->default_row = new_col;
    else {
        /* sort in order just because (needed for add_row support) */
        for (ptr = table_set->default_row, pptr = NULL;
             ptr;
             pptr = ptr, ptr = ptr->next) {
            if (ptr->column > column) {
                new_col->next = ptr;
                if (pptr)
                    pptr->next = new_col;
                else
                    table_set->default_row = new_col;
                return SNMPERR_SUCCESS;
            }
        }
        if (pptr)
            pptr->next = new_col;
        else
            snmp_log(LOG_ERR,"Shouldn't have gotten here: table_dataset/add_row");
    }
    return SNMPERR_SUCCESS;
}

/** adds multiple data column definitions to each row.  Functionally,
 *  this is a wrapper around calling netsnmp_table_set_add_default_row
 *  repeatedly for you.
 */
void
#if HAVE_STDARG_H
netsnmp_table_set_multi_add_default_row(netsnmp_table_data_set *tset, ...)
#else
netsnmp_table_set_multi_add_default_row(va_dcl
    )
     va_dcl
#endif
{
    va_list         debugargs;
    unsigned int    column;
    int             type, writable;
    void           *data;
    size_t          data_len;

#if HAVE_STDARG_H
    va_start(debugargs, tset);
#else
    netsnmp_table_data_set *tset;

    va_start(debugargs);
    tset = va_arg(debugargs, netsnmp_table_data_set *);
#endif

    while ((column = va_arg(debugargs, unsigned int)) != 0) {
        type = va_arg(debugargs, int);
        writable = va_arg(debugargs, int);
        data = va_arg(debugargs, void *);
        data_len = va_arg(debugargs, size_t);
        netsnmp_table_set_add_default_row(tset, column, type, writable,
                                          data, data_len);
    }

    va_end(debugargs);
}


/* ==================================
 *
 * Data Set API: MIB maintenance
 *
 * ================================== */

/** Given a netsnmp_table_data_set definition, create a handler for it */
netsnmp_mib_handler *
netsnmp_get_table_data_set_handler(netsnmp_table_data_set *data_set)
{
    netsnmp_mib_handler *ret = NULL;

    if (!data_set) {
        snmp_log(LOG_INFO,
                 "netsnmp_get_table_data_set_handler(NULL) called\n");
        return NULL;
    }

    ret =
        netsnmp_create_handler(TABLE_DATA_SET_NAME,
                               netsnmp_table_data_set_helper_handler);
    if (ret) {
        ret->flags |= MIB_HANDLER_AUTO_NEXT;
        ret->myvoid = (void *) data_set;
    }
    return ret;
}

/** register a given data_set at a given oid (specified in the
    netsnmp_handler_registration pointer).  The
    reginfo->handler->access_method *may* be null if the call doesn't
    ever want to be called for SNMP operations.
*/
int
netsnmp_register_table_data_set(netsnmp_handler_registration *reginfo,
                                netsnmp_table_data_set *data_set,
                                netsnmp_table_registration_info *table_info)
{
    if (NULL == table_info) {
        /*
         * allocate the table if one wasn't allocated 
         */
        table_info = SNMP_MALLOC_TYPEDEF(netsnmp_table_registration_info);
    }

    if (NULL == table_info->indexes && data_set->table->indexes_template) {
        /*
         * copy the indexes in 
         */
        table_info->indexes =
            snmp_clone_varbind(data_set->table->indexes_template);
    }

    if ((!table_info->min_column || !table_info->max_column) &&
        (data_set->default_row)) {
        /*
         * determine min/max columns 
         */
        unsigned int    mincol = 0xffffffff, maxcol = 0;
        netsnmp_table_data_set_storage *row;

        for (row = data_set->default_row; row; row = row->next) {
            mincol = SNMP_MIN(mincol, row->column);
            maxcol = SNMP_MAX(maxcol, row->column);
        }
        if (!table_info->min_column)
            table_info->min_column = mincol;
        if (!table_info->max_column)
            table_info->max_column = maxcol;
    }

    netsnmp_inject_handler(reginfo,
                           netsnmp_get_table_data_set_handler(data_set));
    return netsnmp_register_table_data(reginfo, data_set->table,
                                       table_info);
}

newrow_stash   *
netsnmp_table_data_set_create_newrowstash
    (netsnmp_table_data_set     *datatable,
     netsnmp_table_request_info *table_info)
{
    newrow_stash   *newrowstash = NULL;
    netsnmp_table_row *newrow   = NULL;

    newrowstash = SNMP_MALLOC_TYPEDEF(newrow_stash);
    newrowstash->created = 1;
    newrow = netsnmp_table_data_set_create_row_from_defaults
                        (datatable->default_row);
    newrow->indexes = snmp_clone_varbind(table_info->indexes);
    newrowstash->newrow = newrow;