baby_steps.c

snmp的源代码,已经在我的ubuntu下编译通过

/*
 * baby_steps.c
 * $Id: baby_steps.c,v 1.10.2.1 2004/12/10 03:30:19 rstory Exp $
 */
#include <net-snmp/net-snmp-config.h>
#include <net-snmp/net-snmp-includes.h>
#include <net-snmp/agent/net-snmp-agent-includes.h>

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

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

#define BABY_STEPS_PER_MODE_MAX     4
#define BSTEP_USE_ORIGINAL          0xffff

static u_short get_mode_map[BABY_STEPS_PER_MODE_MAX] = {
    MODE_BSTEP_PRE_REQUEST, MODE_BSTEP_OBJECT_LOOKUP, BSTEP_USE_ORIGINAL, MODE_BSTEP_POST_REQUEST };

static u_short set_mode_map[SNMP_MSG_INTERNAL_SET_MAX][BABY_STEPS_PER_MODE_MAX] = {
    /*R1*/
    { MODE_BSTEP_PRE_REQUEST, MODE_BSTEP_OBJECT_LOOKUP, MODE_BSTEP_ROW_CREATE,
      MODE_BSTEP_CHECK_VALUE },
    /*R2*/
    { MODE_BSTEP_UNDO_SETUP, BABY_STEP_NONE, BABY_STEP_NONE, BABY_STEP_NONE },
    /*A */
    { MODE_BSTEP_SET_VALUE,MODE_BSTEP_CHECK_CONSISTENCY,
      MODE_BSTEP_COMMIT, BABY_STEP_NONE },
    /*C */
    { MODE_BSTEP_IRREVERSIBLE_COMMIT, MODE_BSTEP_UNDO_CLEANUP, MODE_BSTEP_POST_REQUEST,
      BABY_STEP_NONE},
    /*F */
    { MODE_BSTEP_UNDO_CLEANUP, MODE_BSTEP_POST_REQUEST, BABY_STEP_NONE,
      BABY_STEP_NONE },
    /*U */
    { MODE_BSTEP_UNDO_COMMIT, MODE_BSTEP_UNDO_SET, MODE_BSTEP_UNDO_CLEANUP,
      MODE_BSTEP_POST_REQUEST}
};

static int
_baby_steps_helper(netsnmp_mib_handler *handler,
                   netsnmp_handler_registration *reginfo,
                   netsnmp_agent_request_info *reqinfo,
                   netsnmp_request_info *requests);
static int
_baby_steps_access_multiplexer(netsnmp_mib_handler *handler,
                               netsnmp_handler_registration *reginfo,
                               netsnmp_agent_request_info *reqinfo,
                               netsnmp_request_info *requests);
    
/** @defgroup baby_steps baby_steps: calls your handler in baby_steps for set processing.
 *  @ingroup handler
 *  @{
 */

/** returns a baby_steps handler that can be injected into a given
 *  handler chain.
 */
netsnmp_mib_handler *
netsnmp_baby_steps_handler_get(u_long modes)
{
    netsnmp_mib_handler *mh;
    netsnmp_baby_steps_modes *md;

    mh = netsnmp_create_handler("baby_steps", _baby_steps_helper);
    if(!mh)
        return NULL;

    md = SNMP_MALLOC_TYPEDEF(netsnmp_baby_steps_modes);
    if (NULL == md) {
        snmp_log(LOG_ERR,"malloc failed in netsnmp_baby_steps_handler_get\n");
        netsnmp_handler_free(mh);
        mh = NULL;
    }
    else {
        mh->myvoid = md;
        if (0 == modes)
            modes = BABY_STEP_ALL;
        md->registered = modes;
    }

    /*
     * don't set MIB_HANDLER_AUTO_NEXT, since we need to call lower
     * handlers with a munged mode.
     */
    
    return mh;
}

/** @internal Implements the baby_steps handler */
static int
_baby_steps_helper(netsnmp_mib_handler *handler,
                         netsnmp_handler_registration *reginfo,
                         netsnmp_agent_request_info *reqinfo,
                         netsnmp_request_info *requests)
{
    netsnmp_baby_steps_modes *bs_modes;
    int save_mode, i, rc = SNMP_ERR_NOERROR;
    u_short *mode_map_ptr;
    
    DEBUGMSGTL(("baby_steps", "Got request, mode %s\n",
                se_find_label_in_slist("agent_mode",reqinfo->mode)));

    bs_modes = handler->myvoid;
    netsnmp_assert(NULL != bs_modes);

    switch (reqinfo->mode) {

    case MODE_SET_RESERVE1:
        /*
         * clear completed modes
         * xxx-rks: this will break for pdus with set requests to different
         * rows in the same table when the handler is set up to use the row
         * merge helper as well (or if requests are serialized).
         */
        bs_modes->completed = 0;
        /** fall through */

    case MODE_SET_RESERVE2:
    case MODE_SET_ACTION:
    case MODE_SET_COMMIT:
    case MODE_SET_FREE:
    case MODE_SET_UNDO:
        mode_map_ptr = set_mode_map[reqinfo->mode];
        break;
            
    default:
        /*
         * clear completed modes
         */
        bs_modes->completed = 0;

        mode_map_ptr = get_mode_map;
    }

    /*
     * NOTE: if you update this chart, please update the versions in
     *       local/mib2c-conf.d/parent-set.m2i
     *       agent/mibgroup/helpers/baby_steps.c
     * while you're at it.
     */
    /*
     ***********************************************************************
     * Baby Steps Flow Chart (2004.06.05)                                  *
     *                                                                     *
     * +--------------+    +================+    U = unconditional path    *
     * |optional state|    ||required state||    S = path for success      *
     * +--------------+    +================+    E = path for error        *
     ***********************************************************************
     *
     *                        +--------------+
     *                        |     pre      |
     *                        |   request    |
     *                        +--------------+
     *                               | U
     * +-------------+        +==============+
     * |    row    |f|<-------||  object    ||
     * |  create   |1|      E ||  lookup    ||
     * +-------------+        +==============+
     *     E |   | S                 | S
     *       |   +------------------>|
     *       |                +==============+
     *       |              E ||   check    ||
     *       |<---------------||   values   ||
     *       |                +==============+
     *       |                       | S
     *       |                +==============+
     *       |       +<-------||   undo     ||
     *       |       |      E ||   setup    ||
     *       |       |        +==============+
     *       |       |               | S
     *       |       |        +==============+
     *       |       |        ||    set     ||-------------------------->+
     *       |       |        ||   value    || E                         |
     *       |       |        +==============+                           |
     *       |       |               | S                                 |
     *       |       |        +--------------+                           |
     *       |       |        |    check     |-------------------------->|
     *       |       |        |  consistency | E                         |
     *       |       |        +--------------+                           |
     *       |       |               | S                                 |
     *       |       |        +==============+         +==============+  |
     *       |       |        ||   commit   ||-------->||     undo   ||  |
     *       |       |        ||            || E       ||    commit  ||  |
     *       |       |        +==============+         +==============+  |
     *       |       |               | S                     U |<--------+
     *       |       |        +--------------+         +==============+
     *       |       |        | irreversible |         ||    undo    ||
     *       |       |        |    commit    |         ||     set    ||
     *       |       |        +--------------+         +==============+
     *       |       |               | U                     U |
     *       |       +-------------->|<------------------------+
     *       |                +==============+
     *       |                ||   undo     ||
     *       |                ||  cleanup   ||
     *       |                +==============+
     *       +---------------------->| U
     *                               |
     *                          (err && f1)------------------->+
     *                               |                         |
     *                        +--------------+         +--------------+
     *                        |    post      |<--------|      row     |
     *                        |   request    |       U |    release   |
     *                        +--------------+         +--------------+
     *
     */
    /*
     * save original mode
     */
    save_mode = reqinfo->mode;
    for(i = 0; i < BABY_STEPS_PER_MODE_MAX; ++i ) {
        /*
         * break if we run out of baby steps for this mode
         */
        if(mode_map_ptr[i] == BABY_STEP_NONE)
            break;

        DEBUGMSGTL(("baby_steps", " baby step mode %s\n",
                    se_find_label_in_slist("babystep_mode",mode_map_ptr[i])));

        /*
         * skip modes the handler didn't register for
         */
        if (BSTEP_USE_ORIGINAL != mode_map_ptr[i]) {
            u_int    mode_flag;

            /*
             * skip undo commit if commit wasn't hit, and
             * undo_cleanup if undo_setup wasn't hit.
             */
            if((MODE_SET_UNDO == save_mode) &&
               (MODE_BSTEP_UNDO_COMMIT == mode_map_ptr[i]) &&
               !(BABY_STEP_COMMIT & bs_modes->completed)) {
                DEBUGMSGTL(("baby_steps",
                            "   skipping commit undo (no commit)\n"));
                continue;
            }
            else if((MODE_SET_FREE == save_mode) &&
               (MODE_BSTEP_UNDO_CLEANUP == mode_map_ptr[i]) &&
               !(BABY_STEP_UNDO_SETUP & bs_modes->completed)) {
                DEBUGMSGTL(("baby_steps",
                            "   skipping undo cleanup (no undo setup)\n"));
                continue;
            }

            reqinfo->mode = mode_map_ptr[i];
            mode_flag = netsnmp_baby_step_mode2flag( mode_map_ptr[i] );
            if((mode_flag & bs_modes->registered))
                bs_modes->completed |= mode_flag;
            else {
                DEBUGMSGTL(("baby_steps",
                            "   skipping mode (not registered)\n"));
                continue;
            }

        
        }
        else {
            reqinfo->mode = save_mode;