extend.c

开发snmp的开发包有两个开放的SNMP开发库

 *  Locate the appropriate entry for a given request
 */
netsnmp_extend *
_extend_find_entry( netsnmp_request_info       *request,
                    netsnmp_table_request_info *table_info,
                    int mode  )
{
    netsnmp_extend            *eptr;
    extend_registration_block *ereg;
    int line_idx;
    oid oid_buf[MAX_OID_LEN];
    int oid_len;
    int i;
    char *token;
    int   token_len;

    if (!request || !table_info || !table_info->indexes
                 || !table_info->indexes->next_variable) {
        DEBUGMSGTL(( "nsExtendTable:output2", "invalid invocation\n"));
        return NULL;
    }

    ereg = _find_extension_block( request->requestvb->name,
                                  request->requestvb->name_length );

    /***
     *  GET handling - find the exact entry being requested
     ***/
    if ( mode == MODE_GET ) {
        DEBUGMSGTL(( "nsExtendTable:output2", "GET: %s / %d\n ",
                      table_info->indexes->val.string,
                     *table_info->indexes->next_variable->val.integer));
        for ( eptr = ereg->ehead; eptr; eptr = eptr->next ) {
            if ( !strcmp( eptr->token, table_info->indexes->val.string ))
                break;
        }

        if ( eptr ) {
            /*
             * Ensure the output is available...
             */
            if (!(eptr->flags & NS_EXTEND_FLAGS_ACTIVE) ||
               (netsnmp_cache_check_and_reload( eptr->cache ) < 0 ))
                return NULL;

            /*
             * ...and check the line requested is valid
             */
            line_idx = *table_info->indexes->next_variable->val.integer;
            if (eptr->numlines < line_idx)
                return NULL;
        }
        return eptr;
    }

        /***
         *  GETNEXT handling - find the first suitable entry
         ***/
    else {
        if (!table_info->indexes->val_len ) {
            DEBUGMSGTL(( "nsExtendTable:output2", "GETNEXT: first entry\n"));
            /*
             * Beginning of the table - find the first active
             *  (and successful) entry, and use the first line of it
             */
            for (eptr = ereg->ehead; eptr; eptr = eptr->next ) {
                if ((eptr->flags & NS_EXTEND_FLAGS_ACTIVE) &&
                    (netsnmp_cache_check_and_reload( eptr->cache ) >= 0 )) {
                    line_idx = 1;
                    break;
                }
            }
        } else {
            token     =  table_info->indexes->val.string;
            token_len =  table_info->indexes->val_len;
            line_idx  = *table_info->indexes->next_variable->val.integer;
            DEBUGMSGTL(( "nsExtendTable:output2", "GETNEXT: %s / %d\n ",
                          token, line_idx ));
            /*
             * Otherwise, find the first entry not earlier
             * than the requested token...
             */
            for (eptr = ereg->ehead; eptr; eptr = eptr->next ) {
                if ( strlen(eptr->token) > token_len )
                    break;
                if ( strlen(eptr->token) == token_len &&
                     strcmp(eptr->token, token) >= 0 )
                    break;
            }
            if (!eptr)
                return NULL;    /* (assuming there is one) */

            /*
             * ... and make sure it's active & the output is available
             * (or use the first following entry that is)
             */
            for (    ; eptr; eptr = eptr->next ) {
                if ((eptr->flags & NS_EXTEND_FLAGS_ACTIVE) &&
                    (netsnmp_cache_check_and_reload( eptr->cache ) >= 0 )) {
                    break;
                }
                line_idx = 1;
            }

            if (!eptr)
                return NULL;    /* (assuming there is one) */

            /*
             *  If we're working with the same entry that was requested,
             *  see whether we've reached the end of the output...
             */
            if (!strcmp( eptr->token, token )) {
                if ( eptr->numlines <= line_idx ) {
                    /*
                     * ... and if so, move on to the first line
                     * of the next (active and successful) entry.
                     */
                    line_idx = 1;
                    for (eptr = eptr->next ; eptr; eptr = eptr->next ) {
                        if ((eptr->flags & NS_EXTEND_FLAGS_ACTIVE) &&
                            (netsnmp_cache_check_and_reload( eptr->cache ) >= 0 )) {
                            break;
                        }
                    }
                } else {
                    /*
                     * Otherwise just use the next line of this entry.
                     */
                    line_idx++;
                }
            }
            else {
                /*
                 * If this is not the same entry that was requested,
                 * then we should return the first line.
                 */
                line_idx = 1;
            }
        }
        if (eptr) {
            DEBUGMSGTL(( "nsExtendTable:output2", "GETNEXT -> %s / %d\n ",
                          eptr->token, line_idx));
            /*
             * Since we're processing a GETNEXT request,
             * now we've found the appropriate entry (and line),
             * we need to update the varbind OID ...
             */
            memset(oid_buf, 0, sizeof(oid_buf));
            oid_len = ereg->oid_len;
            memcpy( oid_buf, ereg->root_oid, oid_len*sizeof(oid));
            oid_buf[ oid_len++ ] = 4;    /* nsExtendOutput2Table */
            oid_buf[ oid_len++ ] = 1;    /* nsExtendOutput2Entry */
            oid_buf[ oid_len++ ] = COLUMN_EXTOUT2_OUTLINE;
                                         /* string token index */
            oid_buf[ oid_len++ ] = strlen(eptr->token);
            for ( i=0; i < (int)strlen(eptr->token); i++ )
                oid_buf[ oid_len+i ] = eptr->token[i];
            oid_len += strlen( eptr->token );
                                         /* plus line number */
            oid_buf[ oid_len++ ] = line_idx;
            snmp_set_var_objid( request->requestvb, oid_buf, oid_len );
            /*
             * ... and index values to match.
             */
            snmp_set_var_value( table_info->indexes,
                                eptr->token, strlen(eptr->token));
            snmp_set_var_value( table_info->indexes->next_variable,
                                &line_idx, sizeof(line_idx));
        }
        return eptr;  /* Finally, signal success */
    }
    return NULL;
}

/*
 *  Multi-line output handler
 *  Locate the appropriate entry (using _extend_find_entry)
 *  and return the appropriate output line
 */
int
handle_nsExtendOutput2Table(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_extend             *extension;
    char *cp;
    int line_idx;
    int len;

    for ( request=requests; request; request=request->next ) {
        if (request->processed)
            continue;

        table_info = netsnmp_extract_table_info( request );
        extension  = _extend_find_entry( request, table_info, reqinfo->mode );

        DEBUGMSGTL(( "nsExtendTable:output2", "varbind: "));
        DEBUGMSGOID(("nsExtendTable:output2", request->requestvb->name,
                                              request->requestvb->name_length));
        DEBUGMSG((   "nsExtendTable:output2", " (%s)\n",
                                    (extension) ? extension->token : "[none]"));

        if (!extension) {
            if (reqinfo->mode == MODE_GET)
                netsnmp_set_request_error(reqinfo, request, SNMP_NOSUCHINSTANCE);
            else
                netsnmp_set_request_error(reqinfo, request, SNMP_ENDOFMIBVIEW);
            continue;
        }

        switch (reqinfo->mode) {
        case MODE_GET:
        case MODE_GETNEXT:
            switch (table_info->colnum) {
            case COLUMN_EXTOUT2_OUTLINE:
                /* 
                 * Determine which line we've been asked for....
                 */
                line_idx = *table_info->indexes->next_variable->val.integer;
                cp  = extension->lines[line_idx-1];

                /* 
                 * ... and how long it is.
                 */
                if ( extension->numlines > line_idx )
                    len = (extension->lines[line_idx])-cp -1;
                else if (cp)
                    len = strlen(cp);
                else
                    len = 0;

                snmp_set_var_typed_value( request->requestvb,
                                          ASN_OCTET_STR, cp, len );
                break;
            default:
                netsnmp_set_request_error(reqinfo, request, SNMP_NOSUCHOBJECT);
                continue;
            }
            break;
        default:
            netsnmp_set_request_error(reqinfo, request, SNMP_ERR_GENERR);
            return SNMP_ERR_GENERR;
        }
    }
    return SNMP_ERR_NOERROR;
}

#ifndef USING_UCD_SNMP_EXTENSIBLE_MODULE
        /*************************
         *
         *  Compatability with the UCD extTable
         *
         *************************/

u_char *
var_extensible_old(struct variable * vp,
                     oid * name,
                     size_t * length,
                     int exact,
                     size_t * var_len, WriteMethod ** write_method)
{
    netsnmp_old_extend *exten = NULL;
    static long     long_ret;
    int idx;

    if (header_simple_table
        (vp, name, length, exact, var_len, write_method, num_compatability_entries))
        return (NULL);

    idx = name[*length-1] -1;
    exten = &compatability_entries[ idx ];
    if (exten) {
        switch (vp->magic) {
        case MIBINDEX:
            long_ret = name[*length - 1];
            return ((u_char *) (&long_ret));
        case ERRORNAME:        /* name defined in config file */
            *var_len = strlen(exten->exec_entry->token);
            return ((u_char *) (exten->exec_entry->token));
        case SHELLCOMMAND:
            *var_len = strlen(exten->exec_entry->command);
            return ((u_char *) (exten->exec_entry->command));
        case ERRORFLAG:        /* return code from the process */
            netsnmp_cache_check_and_reload( exten->exec_entry->cache );
            long_ret = exten->exec_entry->result;
            return ((u_char *) (&long_ret));
        case ERRORMSG:         /* first line of text returned from the process */
            netsnmp_cache_check_and_reload( exten->exec_entry->cache );
            if (exten->exec_entry->numlines > 1) {
                *var_len = (exten->exec_entry->lines[1])-
                           (exten->exec_entry->output) -1;
            } else if (exten->exec_entry->output) {
                *var_len = strlen(exten->exec_entry->output);
            } else {
                *var_len = 0;
            }
            return ((u_char *) (exten->exec_entry->output));
        case ERRORFIX:
            *write_method = fixExec2Error;
            long_return = 0;
            return ((u_char *) &long_return);

        case ERRORFIXCMD:
            if (exten->efix_entry) {
                *var_len = strlen(exten->efix_entry->command);
                return ((u_char *) exten->efix_entry->command);
            } else {
                *var_len = 0;
                return ((u_char *) &long_return);  /* Just needs to be non-null! */
            }
        }
        return NULL;
    }
    return NULL;
}


int
fixExec2Error(int action,
             u_char * var_val,
             u_char var_val_type,
             size_t var_val_len,
             u_char * statP, oid * name, size_t name_len)
{
    netsnmp_old_extend *exten = NULL;
    int idx;

    idx = name[name_len-1] -1;
    exten = &compatability_entries[ idx ];

    switch (action) {
    case MODE_SET_RESERVE1:
        if (var_val_type != ASN_INTEGER) {
            snmp_log(LOG_ERR, "Wrong type != int\n");
            return SNMP_ERR_WRONGTYPE;
        }
        idx = *((long *) var_val);
        if (idx != 1) {
            snmp_log(LOG_ERR, "Wrong value != 1\n");
            return SNMP_ERR_WRONGVALUE;
        }
        if (!exten || !exten->efix_entry) {
            snmp_log(LOG_ERR, "No command to run\n");
            return SNMP_ERR_GENERR;
        }
        return SNMP_ERR_NOERROR;

    case MODE_SET_COMMIT:
        netsnmp_cache_check_and_reload( exten->efix_entry->cache );
    }
    return SNMP_ERR_NOERROR;
}
#endif