snmp_vars.c

来自「eCos操作系统源码」· C语言 代码 · 共 566 行 · 第 1/2 页

 * int	    action;	    IN - RESERVE1, RESERVE2, COMMIT, or FREE
 * u_char   *var_val;	    IN - input or output buffer space
 * u_char   var_val_type;   IN - type of input buffer
 * int	    var_val_len;    IN - input and output buffer len
 * u_char   *statP;	    IN - pointer to local statistic
 * oid      *name           IN - pointer to name requested
 * int      name_len        IN - number of sub-ids in the name
 */

long		long_return;
#ifndef ibm032
u_char		return_buf[258];  
#else
u_char		return_buf[256]; /* nee 64 */
#endif

struct timeval	starttime;

void
init_agent (const char *app)
{
  /* get current time (ie, the time the agent started) */
  gettimeofday(&starttime, NULL);
  starttime.tv_sec--;
  starttime.tv_usec += 1000000L;

  /* we handle alarm signals ourselves in the select loop */
  ds_set_boolean(DS_LIBRARY_ID, DS_LIB_ALARM_DONT_USE_SIG, 1);

#ifdef CYGPKG_SNMPAGENT_V3_SUPPORT
  usm_set_reportErrorOnUnknownID(1);
#endif

#ifdef CAN_USE_NLIST
  init_kmem("/dev/kmem");
#endif

  setup_tree();

  init_agent_read_config(app);

#ifdef TESTING
  auto_nlist_print_tree(-2, 0);
#endif

  /* initialize agentx subagent if necessary. */
#ifdef USING_AGENTX_SUBAGENT_MODULE
  if(ds_get_boolean(DS_APPLICATION_ID, DS_AGENT_ROLE) == SUB_AGENT)
      subagent_pre_init();
#endif

}  /* end init_agent() */



oid nullOid[] = {0,0};
int nullOidLen = sizeof(nullOid)/sizeof(oid);

/*
 * getStatPtr - return a pointer to the named variable, as well as it's
 * type, length, and access control list.
 * Now uses 'search_subtree' (recursively) and 'search_subtree_vars'
 * to do most of the work
 *
 * If an exact match for the variable name exists, it is returned.  If not,
 * and exact is false, the next variable lexicographically after the
 * requested one is returned.
 *
 * If no appropriate variable can be found, NULL is returned.
 */
static  int 		found;

static u_char *
search_subtree_vars(struct subtree *tp,
		    oid *name,    /* IN - name of var, OUT - name matched */
		    size_t *namelen, /* IN -number of sub-ids in name,
                                     OUT - subid-is in matched name */
		    u_char *type, /* OUT - type of matched variable */
		    size_t *len,  /* OUT - length of matched variable */
		    u_short *acl, /* OUT - access control list */
		    int exact,    /* IN - TRUE if exact match wanted */
		    WriteMethod **write_method,
		    struct snmp_pdu *pdu, /* IN - relevant auth info re PDU */
		    int *noSuchObject)
{
    register struct variable *vp;
    struct variable	compat_var, *cvp = &compat_var;
    register int	x;
    u_char		*access = NULL;
    int			result;
    oid 		*suffix;
    size_t		suffixlen;
#if MIB_CLIENTS_ARE_EVIL
    oid			save[MAX_OID_LEN];
    size_t		savelen = 0;
#endif

	    if ( tp->variables == NULL )
		return NULL;

	    result = compare_tree(name, *namelen, tp->name, tp->namelen);
	    suffixlen = *namelen - tp->namelen;
	    suffix = name + tp->namelen;
	    /* the following is part of the setup for the compatability
	       structure below that has been moved out of the main loop.
	     */
	    memcpy(cvp->name, tp->name, tp->namelen * sizeof(oid));

            *noSuchObject = TRUE;	/* In case of null variables_len */
	    for(x = 0, vp = tp->variables; x < tp->variables_len;
		vp =(struct variable *)((char *)vp +tp->variables_width), x++){
		/* if exact and ALWAYS
		   if next  and result >= 0 */
                /* and if vp->namelen != 0   -- Wes */
		if (vp->namelen && (exact || result >= 0)){
		    result = compare_tree(suffix, suffixlen, vp->name,
				     vp->namelen);
		}
		/* if exact and result == 0
		   if next  and result <= 0 */
                /* or if vp->namelen == 0    -- Wes */
		if ((!exact && (result <= 0)) || (exact && (result == 0)) ||
                  vp->namelen == 0) {
		    /* builds an old (long) style variable structure to retain
		       compatability with var_* functions written previously.
		     */
                  if (vp->namelen)
                    memcpy((cvp->name + tp->namelen),
			  vp->name, vp->namelen * sizeof(oid));
		    cvp->namelen = tp->namelen + vp->namelen;
		    cvp->type = vp->type;
		    cvp->magic = vp->magic;
		    cvp->acl = vp->acl;
		    cvp->findVar = vp->findVar;
                    *write_method = NULL;
#if MIB_CLIENTS_ARE_EVIL
                    memcpy(save, name, *namelen*sizeof(oid));
                    savelen = *namelen;
#endif
		    DEBUGMSGTL(("snmp_vars", "Trying variable: "));
		    DEBUGMSGOID(("snmp_vars", cvp->name, cvp->namelen));
		    DEBUGMSG(("snmp_vars"," ...\n"));

		gaga:
		    access = (*(vp->findVar))(cvp, name, namelen, exact,
						  len, write_method);
	    	    DEBUGMSGTL(("snmp_vars", "Returned %s\n",
				(access==NULL) ? "(null)" : "something" ));

			/*
			 * Check that the answer is acceptable.
			 *  i.e. lies within the current subtree chunk
			 *
			 * It might be worth saving this answer just in
			 *  case it turns out to be valid, but for now
			 *  we'll simply discard it.
			 */
		    if ( access && snmp_oid_compare(name, *namelen,
						    tp->end, tp->end_len) > 0) {
			memcpy(name, tp->end, tp->end_len);
			access = 0;
		    }
#if MIB_CLIENTS_ARE_EVIL
                    if (access == NULL) {
		      if (snmp_oid_compare(name, *namelen, save, savelen) != 0) {
			DEBUGMSGTL(("snmp_vars", "evil_client: "));
			DEBUGMSGOID(("snmp_vars", save, savelen));
			DEBUGMSG(("snmp_vars"," =>"));
			DEBUGMSGOID(("snmp_vars", name, *namelen));
			DEBUGMSG(("snmp_vars","\n"));
                        memcpy(name, save, savelen*sizeof(oid));
                        *namelen = savelen;
                      }
                    }
#endif
		    if (*write_method)
			*acl = cvp->acl;
                    /* check for permission to view this part of the OID tree */
		    if ((access != NULL || (*write_method != NULL && exact)) &&
                        in_a_view(name, namelen, pdu, cvp->type)) {
			if ( access && !exact ) {
				/*
				 * We've got an answer, but shouldn't use it.
				 * But we *might* be able to use a later
				 *  instance of the same object, so we can't
				 *  legitimately move on to the next variable
				 *  in the variable structure just yet.
				 * Let's try re-calling the findVar routine
				 *  with the returned name, and see whether
				 *  the next answer is acceptable
				 */
			   *write_method = NULL;
			   goto gaga;
			}
                        access = NULL;
			*write_method = NULL;
		    } else if (exact){
			found = TRUE;
		    }
		    if (access != NULL || (*write_method != NULL && exact))
			break;
		}
		/* if exact and result <= 0 */
		if (exact && (result  <= 0)){
	            *type = cvp->type;
		    *acl = cvp->acl;
		    if (found)
                      *noSuchObject = FALSE;
		    else
                      *noSuchObject = TRUE;
		    return NULL;
		}
	    }
	    if (access != NULL || (exact && *write_method != NULL)) {
	        *type = cvp->type;
		*acl = cvp->acl;
		return access;
	    }
	    return NULL;
}

u_char *
getStatPtr(
    oid		*name,	    /* IN - name of var, OUT - name matched */
    size_t	*namelen,   /* IN -number of sub-ids in name,
                               OUT - subid-is in matched name */
    u_char	*type,	    /* OUT - type of matched variable */
    size_t	*len,	    /* OUT - length of matched variable */
    u_short	*acl,	    /* OUT - access control list */
    int		exact,	    /* IN - TRUE if exact match wanted */
    WriteMethod **write_method,
    struct snmp_pdu *pdu,   /* IN - relevant auth info re PDU */
    int		*noSuchObject)
{
    struct subtree	*tp;
    oid			save[MAX_OID_LEN];
    size_t		savelen = 0;
    u_char              result_type;
    u_short             result_acl;
    u_char        	*search_return=NULL;

    found = FALSE;

    if (!exact){
	memcpy(save, name, *namelen * sizeof(oid));
	savelen = *namelen;
    }
    *write_method = NULL;

    DEBUGMSGTL(("snmp_vars", "Looking for: "));
    DEBUGMSGOID(("snmp_vars", name, *namelen));
    DEBUGMSG(("snmp_vars"," ...\n"));

    tp = find_subtree(name, *namelen, NULL);
    
    while ( search_return == NULL && tp != NULL ) {
	DEBUGMSGTL(("snmp_vars", "Trying tree: "));
	DEBUGMSGOID(("snmp_vars", tp->name, tp->namelen));
	DEBUGMSG(("snmp_vars"," ...\n"));
	search_return = search_subtree_vars( tp, name, namelen, &result_type,
                                        len, &result_acl, exact, write_method,
                                        pdu, noSuchObject);
	if ( search_return != NULL || exact )
	    break;
	tp = tp->next;
    }
    if ( tp == NULL ) {
	if (!search_return && !exact){
	    memcpy(name, save, savelen * sizeof(oid));
	    *namelen = savelen;
	}
	if (found)
	    *noSuchObject = FALSE;
	else
	    *noSuchObject = TRUE;
        return NULL;
    }
    *type = result_type;
    *acl =  result_acl;
    return search_return;
}