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  <h1>cache_handler.c</h1>

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00001 <span class="preprocessor">#include &lt;net-snmp/net-snmp-config.h&gt;</span>
00002 
00003 <span class="preprocessor">#if HAVE_STRING_H</span>
00004 <span class="preprocessor">#include &lt;string.h&gt;</span>
00005 <span class="preprocessor">#else</span>
00006 <span class="preprocessor">#include &lt;strings.h&gt;</span>
00007 <span class="preprocessor">#endif</span>
00008 
00009 <span class="preprocessor">#include &lt;net-snmp/net-snmp-includes.h&gt;</span>
00010 <span class="preprocessor">#include &lt;net-snmp/agent/net-snmp-agent-includes.h&gt;</span>
00011 
00012 <span class="preprocessor">#include &lt;net-snmp/agent/cache_handler.h&gt;</span>
00013 
00014 <span class="keyword">static</span> netsnmp_cache  *cache_head = NULL;
00015 <span class="keyword">static</span> <span class="keywordtype">int</span>             cache_outstanding_valid = 0;
00016 <span class="keyword">static</span> <span class="keywordtype">int</span>             _cache_load( netsnmp_cache *cache );
00017 
00018 <span class="preprocessor">#define CACHE_RELEASE_FREQUENCY 60      </span><span class=
"comment">/* Check for expired caches every 60s */</span>
00019 
00020 <span class="keywordtype">void</span>            <a class="code" href=
"group__cache__handler.html#ga21">release_cached_resources</a>(<span class="keywordtype">unsigned</span> <span class=
"keywordtype">int</span> regNo,
00021                                          <span class="keywordtype">void</span> *clientargs);
00022 
00110 netsnmp_cache *
<a name="l00111" id="l00111"></a><a class="code" href="group__cache__handler.html#ga0">00111</a> <a class="code" href=
"group__cache__handler.html#ga0">netsnmp_cache_get_head</a>(<span class="keywordtype">void</span>)
00112 {
00113     <span class="keywordflow">return</span> cache_head;
00114 }
00115 
00118 netsnmp_cache *
<a name="l00119" id="l00119"></a><a class="code" href="group__cache__handler.html#ga1">00119</a> <a class="code" href=
"group__cache__handler.html#ga1">netsnmp_cache_find_by_oid</a>(oid * rootoid, <span class="keywordtype">int</span> rootoid_len)
00120 {
00121     netsnmp_cache  *cache;
00122 
00123     <span class="keywordflow">for</span> (cache = cache_head; cache; cache = cache-&gt;next) {
00124         <span class="keywordflow">if</span> (0 == <a class="code" href=
"group__library.html#ga106">netsnmp_oid_equals</a>(cache-&gt;rootoid, cache-&gt;rootoid_len,
00125                                     rootoid, rootoid_len))
00126             <span class="keywordflow">return</span> cache;
00127     }
00128     
00129     <span class="keywordflow">return</span> NULL;
00130 }
00131 
00134 netsnmp_cache *
<a name="l00135" id="l00135"></a><a class="code" href="group__cache__handler.html#ga2">00135</a> <a class="code" href=
"group__cache__handler.html#ga2">netsnmp_cache_create</a>(<span class=
"keywordtype">int</span> timeout, NetsnmpCacheLoad * load_hook,
00136                      NetsnmpCacheFree * free_hook,
00137                      oid * rootoid, <span class="keywordtype">int</span> rootoid_len)
00138 {
00139     netsnmp_cache  *cache = NULL;
00140 
00141     cache = <a class="code" href="group__util.html#ga39">SNMP_MALLOC_TYPEDEF</a>(netsnmp_cache);
00142     <span class="keywordflow">if</span> (NULL == cache) {
00143         <a class="code" href="group__snmp__logging.html#ga41">snmp_log</a>(LOG_ERR,<span class=
"stringliteral">"malloc error in netsnmp_cache_create\n"</span>);
00144         <span class="keywordflow">return</span> NULL;
00145     }
00146     cache-&gt;timeout = timeout;
00147     cache-&gt;load_cache = load_hook;
00148     cache-&gt;free_cache = free_hook;
00149     cache-&gt;enabled = 1;
00150 
00151     <span class="keywordflow">if</span>(0 == cache-&gt;timeout)
00152         cache-&gt;timeout = netsnmp_ds_get_int(NETSNMP_DS_APPLICATION_ID,
00153                                             NETSNMP_DS_AGENT_CACHE_TIMEOUT);
00154 
00155     
00156     <span class="comment">/*</span>
00157 <span class="comment">     * Add the registered OID information, and tack</span>
00158 <span class="comment">     * this onto the list for cache SNMP management</span>
00159 <span class="comment">     *</span>
00160 <span class="comment">     * Note that this list is not ordered.</span>
00161 <span class="comment">     *    table_iterator rules again!</span>
00162 <span class="comment">     */</span>
00163     <span class="keywordflow">if</span> (rootoid) {
00164         cache-&gt;rootoid = snmp_duplicate_objid(rootoid, rootoid_len);
00165         cache-&gt;rootoid_len = rootoid_len;
00166         cache-&gt;next = cache_head;
00167         <span class="keywordflow">if</span> (cache_head)
00168             cache_head-&gt;prev = cache;
00169         cache_head = cache;
00170     }
00171 
00172     <span class="keywordflow">return</span> cache;
00173 }
00174 
00176 <span class="keyword">static</span> <span class="keywordtype">void</span>
00177 _timer_reload(<span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> regNo, <span class=
"keywordtype">void</span> *clientargs)
00178 {
00179     netsnmp_cache *cache = (netsnmp_cache *)clientargs;
00180 
00181     DEBUGMSGT((<span class="stringliteral">"cache_timer:start"</span>, <span class=
"stringliteral">"loading cache %p\n"</span>, cache));
00182 
00183     cache-&gt;expired = 1;
00184 
00185     _cache_load(cache);
00186 }
00187 
00189 <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span>
<a name="l00190" id="l00190"></a><a class="code" href="group__cache__handler.html#ga4">00190</a> <a class="code" href=
"group__cache__handler.html#ga4">netsnmp_cache_timer_start</a>(netsnmp_cache *cache)
00191 {
00192     <span class="keywordflow">if</span>(NULL == cache)
00193         <span class="keywordflow">return</span> 0;
00194 
00195     DEBUGMSGTL(( <span class="stringliteral">"cache_timer:start"</span>, <span class="stringliteral">"OID: "</span>));
00196     DEBUGMSGOID((<span class="stringliteral">"cache_timer:start"</span>, cache-&gt;rootoid, cache-&gt;rootoid_len));
00197     DEBUGMSG((   <span class="stringliteral">"cache_timer:start"</span>, <span class="stringliteral">"\n"</span>));
00198 
00199     <span class="keywordflow">if</span>(0 != cache-&gt;timer_id) {
00200         <a class="code" href="group__snmp__logging.html#ga41">snmp_log</a>(LOG_WARNING, <span class=
"stringliteral">"cache has existing timer id.\n"</span>);
00201         <span class="keywordflow">return</span> cache-&gt;timer_id;
00202     }
00203     
00204     <span class="keywordflow">if</span>(! (cache-&gt;flags &amp; NETSNMP_CACHE_AUTO_RELOAD)) {
00205         <a class="code" href="group__snmp__logging.html#ga41">snmp_log</a>(LOG_ERR,
00206                  <span class="stringliteral">"cache_timer_start called but auto_reload not set.\n"</span>);
00207         <span class="keywordflow">return</span> 0;
00208     }
00209 
00210     cache-&gt;timer_id = <a class="code" href=
"group__snmp__alarm.html#ga14">snmp_alarm_register</a>(cache-&gt;timeout, SA_REPEAT,
00211                                           _timer_reload, cache);
00212     <span class="keywordflow">if</span>(0 == cache-&gt;timer_id) {
00213         <a class="code" href="group__snmp__logging.html#ga41">snmp_log</a>(LOG_ERR,<span class=
"stringliteral">"could not register alarm\n"</span>);
00214         <span class="keywordflow">return</span> 0;
00215     }
00216 
00217     cache-&gt;flags &amp;= ~NETSNMP_CACHE_AUTO_RELOAD;
00218     DEBUGMSGT((<span class="stringliteral">"cache_timer:start"</span>,
00219                <span class="stringliteral">"starting timer %d for cache %p\n"</span>, cache-&gt;timer_id, cache));
00220     <span class="keywordflow">return</span> cache-&gt;timer_id;
00221 }
00222 
00224 <span class="keywordtype">void</span>
<a name="l00225" id="l00225"></a><a class="code" href="group__cache__handler.html#ga5">00225</a> <a class="code" href=
"group__cache__handler.html#ga5">netsnmp_cache_timer_stop</a>(netsnmp_cache *cache)
00226 {
00227     <span class="keywordflow">if</span>(NULL == cache)
00228         <span class="keywordflow">return</span>;
00229 
00230     <span class="keywordflow">if</span>(0 == cache-&gt;timer_id) {
00231         <a class="code" href="group__snmp__logging.html#ga41">snmp_log</a>(LOG_WARNING, <span class=
"stringliteral">"cache has no timer id.\n"</span>);
00232         <span class="keywordflow">return</span>;
00233     }
00234 
00235     DEBUGMSGT((<span class="stringliteral">"cache_timer:stop"</span>,
00236                <span class="stringliteral">"stopping timer %d for cache %p\n"</span>, cache-&gt;timer_id, cache));
00237 
00238     <a class="code" href="group__snmp__alarm.html#ga6">snmp_alarm_unregister</a>(cache-&gt;timer_id);
00239     cache-&gt;flags |= NETSNMP_CACHE_AUTO_RELOAD;
00240 }
00241 
00242 
00245 <a class="code" href="structnetsnmp__mib__handler__s.html">netsnmp_mib_handler</a> *
<a name="l00246" id="l00246"></a><a class="code" href="group__cache__handler.html#ga6">00246</a> <a class="code" href=
"group__cache__handler.html#ga6">netsnmp_cache_handler_get</a>(netsnmp_cache* cache)
00247 {
00248     <a class="code" href="structnetsnmp__mib__handler__s.html">netsnmp_mib_handler</a> *ret = NULL;
00249     
00250     ret = <a class="code" href="group__handler.html#ga7">netsnmp_create_handler</a>(<span class=
"stringliteral">"cache_handler"</span>,
00251                                  netsnmp_cache_helper_handler);
00252     <span class="keywordflow">if</span> (ret) {
00253         ret-&gt;<a class="code" href="structnetsnmp__mib__handler__s.html#o2">flags</a> |= MIB_HANDLER_AUTO_NEXT;
00254         ret-&gt;<a class="code" href="structnetsnmp__mib__handler__s.html#o1">myvoid</a> = (<span class=
"keywordtype">void</span> *) cache;
00255         
00256         <span class="keywordflow">if</span>(NULL != cache) {
00257             <span class=
"keywordflow">if</span> ((cache-&gt;flags &amp; NETSNMP_CACHE_PRELOAD) &amp;&amp; ! cache-&gt;valid) {
00258                 <span class="comment">/*</span>
00259 <span class="comment">                 * load cache, ignore rc</span>
00260 <span class="comment">                 * (failed load doesn't affect registration)</span>
00261 <span class="comment">                 */</span>
00262                 (void)_cache_load(cache);
00263             }
00264             <span class="keywordflow">if</span> (cache-&gt;flags &amp; NETSNMP_CACHE_AUTO_RELOAD)
00265                 <a class="code" href="group__cache__handler.html#ga4">netsnmp_cache_timer_start</a>(cache);
00266             
00267         }
00268     }
00269     <span class="keywordflow">return</span> ret;
00270 }
00271 
00274 <a class="code" href="structnetsnmp__mib__handler__s.html">netsnmp_mib_handler</a> *
<a name="l00275" id="l00275"></a><a class="code" href="group__cache__handler.html#ga7">00275</a> <a class="code" href=
"group__cache__handler.html#ga7">netsnmp_get_cache_handler</a>(<span class=
"keywordtype">int</span> timeout, NetsnmpCacheLoad * load_hook,
00276                           NetsnmpCacheFree * free_hook,
00277                           oid * rootoid, <span class="keywordtype">int</span> rootoid_len)
00278 {
00279     <a class="code" href="structnetsnmp__mib__handler__s.html">netsnmp_mib_handler</a> *ret = NULL;
00280     netsnmp_cache  *cache = NULL;
00281 
00282     ret = <a class="code" href="group__cache__handler.html#ga6">netsnmp_cache_handler_get</a>(NULL);
00283     <span class="keywordflow">if</span> (ret) {
00284         cache = <a class="code" href=
"group__cache__handler.html#ga2">netsnmp_cache_create</a>(timeout, load_hook, free_hook,
00285                                      rootoid, rootoid_len);
00286         ret-&gt;<a class="code" href="structnetsnmp__mib__handler__s.html#o1">myvoid</a> = (<span class=
"keywordtype">void</span> *) cache;
00287     }
00288     <span class="keywordflow">return</span> ret;
00289 }
00290 
00293 <span class="keywordtype">int</span>
<a name="l00294" id="l00294"></a><a class="code" href="group__cache__handler.html#ga8">00294</a> <a class="code" href=
"group__cache__handler.html#ga8">netsnmp_cache_handler_register</a>(<a class="code" href=
"structnetsnmp__handler__registration__s.html">netsnmp_handler_registration</a> * reginfo,
00295                                netsnmp_cache* cache)
00296 {
00297     <a class="code" href="structnetsnmp__mib__handler__s.html">netsnmp_mib_handler</a> *handler = NULL;
00298     handler = <a class="code" href="group__cache__handler.html#ga6">netsnmp_cache_handler_get</a>(cache);
00299 
00300     <a class="code" href="group__handler.html#ga14">netsnmp_inject_handler</a>(reginfo, handler);
00301     <span class="keywordflow">return</span> <a class="code" href=
"group__handler.html#ga10">netsnmp_register_handler</a>(reginfo);
00302 }
00303 
00306 <span class="keywordtype">int</span>
<a name="l00307" id="l00307"></a><a class="code" href="group__cache__handler.html#ga9">00307</a> <a class="code" href=
"group__cache__handler.html#ga9">netsnmp_register_cache_handler</a>(<a class="code" href=
"structnetsnmp__handler__registration__s.html">netsnmp_handler_registration</a> * reginfo,
00308                                <span class="keywordtype">int</span> timeout, NetsnmpCacheLoad * load_hook,
00309                                NetsnmpCacheFree * free_hook)
00310 {
00311     <a class="code" href="structnetsnmp__mib__handler__s.html">netsnmp_mib_handler</a> *handler = NULL;
00312     handler = <a class="code" href=
"group__cache__handler.html#ga7">netsnmp_get_cache_handler</a>(timeout, load_hook, free_hook,
00313                                         reginfo-&gt;<a class="code" href=
"structnetsnmp__handler__registration__s.html#o2">rootoid</a>,
00314                                         reginfo-&gt;<a class="code" href=
"structnetsnmp__handler__registration__s.html#o3">rootoid_len</a>);
00315 
00316     <a class="code" href="group__handler.html#ga14">netsnmp_inject_handler</a>(reginfo, handler);
00317     <span class="keywordflow">return</span> <a class="code" href=
"group__handler.html#ga10">netsnmp_register_handler</a>(reginfo);
00318 }
00319 
00320 NETSNMP_STATIC_INLINE <span class="keywordtype">char</span> *
00321 _build_cache_name(<span class="keyword">const</span> <span class="keywordtype">char</span> *name)
00322 {
00323     <span class="keywordtype">char</span> *dup = malloc(strlen(name) + strlen(CACHE_NAME) + 2);
00324     <span class="keywordflow">if</span> (NULL == dup)
00325         <span class="keywordflow">return</span> NULL;
00326     sprintf(dup, <span class="stringliteral">"%s:%s"</span>, CACHE_NAME, name);
00327     <span class="keywordflow">return</span> dup;
00328 }
00329 
00331 <span class="keywordtype">void</span>
<a name="l00332" id="l00332"></a><a class="code" href="group__cache__handler.html#ga11">00332</a> <a class="code" href=
"group__cache__handler.html#ga11">netsnmp_cache_reqinfo_insert</a>(netsnmp_cache* cache,
00333                              <a class="code" href=
"structnetsnmp__agent__request__info__s.html">netsnmp_agent_request_info</a> * reqinfo,
00334                              <span class="keyword">const</span> <span class="keywordtype">char</span> *name)
00335 {
00336     <span class="keywordtype">char</span> *cache_name = _build_cache_name(name);
00337     <span class="keywordflow">if</span> (NULL == netsnmp_agent_get_list_data(reqinfo, cache_name)) {
00338         DEBUGMSGTL((<span class="stringliteral">"verbose:helper:cache_handler"</span>, <span class=
"stringliteral">" adding '%s' to %p\n"</span>,
00339                     cache_name, reqinfo));
00340         netsnmp_agent_add_list_data(reqinfo,
00341                                     <a class="code" href=
"group__data__list.html#ga3">netsnmp_create_data_list</a>(cache_name,
00342                                                              cache, NULL));
00343     }
00344     <a class="code" href="group__util.html#ga36">SNMP_FREE</a>(cache_name);
00345 }
00346 
00348 netsnmp_cache  *
<a name="l00349" id="l00349"></a><a class="code" href="group__cache__handler.html#ga12">00349</a> <a class="code" href=
"group__cache__handler.html#ga12">netsnmp_cache_reqinfo_extract</a>(<a class="code" href=
"structnetsnmp__agent__request__info__s.html">netsnmp_agent_request_info</a> * reqinfo,
00350                               <span class="keyword">const</span> <span class="keywordtype">char</span> *name)
00351 {
00352     netsnmp_cache  *result;
00353     <span class="keywordtype">char</span> *cache_name = _build_cache_name(name);
00354     result = netsnmp_agent_get_list_data(reqinfo, cache_name);
00355     <a class="code" href="group__util.html#ga36">SNMP_FREE</a>(cache_name);
00356     <span class="keywordflow">return</span> result;
00357 }
00358 
00360 netsnmp_cache  *
<a name="l00361" id="l00361"></a><a class="code" href="group__cache__handler.html#ga13">00361</a> <a class="code" href=
"group__cache__handler.html#ga13">netsnmp_extract_cache_info</a>(<a class="code" href=
"structnetsnmp__agent__request__info__s.html">netsnmp_agent_request_info</a> * reqinfo)
00362 {
00363     <span class="keywordflow">return</span> <a class="code" href=
"group__cache__handler.html#ga12">netsnmp_cache_reqinfo_extract</a>(reqinfo, CACHE_NAME);
00364 }
00365 
00366 
00368 <span class="keywordtype">int</span>
<a name="l00369" id="l00369"></a><a class="code" href="group__cache__handler.html#ga14">00369</a> <a class="code" href=
"group__cache__handler.html#ga14">netsnmp_cache_check_expired</a>(netsnmp_cache *cache)
00370 {
00371     <span class="keywordflow">if</span>(NULL == cache)
00372         <span class="keywordflow">return</span> 0;
00373     
00374     <span class="keywordflow">if</span>(!cache-&gt;valid || (NULL == cache-&gt;timestamp) || (-1 == cache-&gt;timeout))
00375         cache-&gt;expired = 1;
00376     <span class="keywordflow">else</span>
00377         cache-&gt;expired = <a class="code" href=
"group__util.html#ga20">atime_ready</a>(cache-&gt;timestamp, 1000 * cache-&gt;timeout);
00378     
00379     <span class="keywordflow">return</span> cache-&gt;expired;
00380 }
00381 
00383 <span class="keywordtype">int</span>
<a name="l00384" id="l00384"></a><a class="code" href="group__cache__handler.html#ga15">00384</a> <a class="code" href=
"group__cache__handler.html#ga15">netsnmp_cache_check_and_reload</a>(netsnmp_cache * cache)
00385 {
00386     <span class="keywordflow">if</span> (!cache) {
00387         DEBUGMSG((<span class="stringliteral">"helper:cache_handler"</span>, <span class=
"stringliteral">" no cache\n"</span>));
00388         <span class="keywordflow">return</span> 0;       <span class="comment">/* ?? or -1 */</span>
00389     }
00390     <span class="keywordflow">if</span> (!cache-&gt;valid || <a class="code" href=
"group__cache__handler.html#ga14">netsnmp_cache_check_expired</a>(cache))
00391         <span class="keywordflow">return</span> _cache_load( cache );
00392     <span class="keywordflow">else</span> {
00393         DEBUGMSG((<span class="stringliteral">"helper:cache_handler"</span>, <span class=
"stringliteral">" cached (%d)\n"</span>,
00394                   cache-&gt;timeout));
00395         <span class="keywordflow">return</span> 0;
00396     }
00397 }
00398 
00400 <span class="keywordtype">int</span>
<a name="l00401" id="l00401"></a><a class="code" href="group__cache__handler.html#ga16">00401</a> <a class="code" href=
"group__cache__handler.html#ga16">netsnmp_cache_is_valid</a>(<a class="code" href=
"structnetsnmp__agent__request__info__s.html">netsnmp_agent_request_info</a> * reqinfo, 
00402                        <span class="keyword">const</span> <span class="keywordtype">char</span>* name)
00403 {
00404     netsnmp_cache  *cache = <a class="code" href=
"group__cache__handler.html#ga12">netsnmp_cache_reqinfo_extract</a>(reqinfo, name);
00405     <span class="keywordflow">return</span> (cache &amp;&amp; cache-&gt;valid);
00406 }
00407 
00411 <span class="keywordtype">int</span>
<a name="l00412" id="l00412"></a><a class="code" href="group__cache__handler.html#ga17">00412</a> <a class="code" href=
"group__cache__handler.html#ga17">netsnmp_is_cache_valid</a>(<a class="code" href=
"structnetsnmp__agent__request__info__s.html">netsnmp_agent_request_info</a> * reqinfo)
00413 {
00414     <span class="keywordflow">return</span> <a class="code" href=
"group__cache__handler.html#ga16">netsnmp_cache_is_valid</a>(reqinfo, CACHE_NAME);
00415 }
00416 
00418 <span class="keywordtype">int</span>
<a name="l00419" id="l00419"></a><a class="code" href="group__cache__handler.html#ga18">00419</a> <a class="code" href=
"group__cache__handler.html#ga18">netsnmp_cache_helper_handler</a>(<a class="code" href=
"structnetsnmp__mib__handler__s.html">netsnmp_mib_handler</a> * handler,
00420                              <a class="code" href=
"structnetsnmp__handler__registration__s.html">netsnmp_handler_registration</a> * reginfo,
00421                              <a class="code" href=
"structnetsnmp__agent__request__info__s.html">netsnmp_agent_request_info</a> * reqinfo,
00422                              <a class="code" href=
"structnetsnmp__request__info__s.html">netsnmp_request_info</a> * requests)
00423 {
00424     netsnmp_cache  *cache = NULL;
00425     netsnmp_handler_args cache_hint;
00426 
00427     DEBUGMSGTL((<span class="stringliteral">"helper:cache_handler"</span>, <span class=
"stringliteral">"Got request (%d) for %s: "</span>,
00428                 reqinfo-&gt;<a class="code" href=
"structnetsnmp__agent__request__info__s.html#o0">mode</a>, reginfo-&gt;<a class="code" href=
"structnetsnmp__handler__registration__s.html#o0">handlerName</a>));
00429     DEBUGMSGOID((<span class="stringliteral">"helper:cache_handler"</span>, reginfo-&gt;<a class="code" href=
"structnetsnmp__handler__registration__s.html#o2">rootoid</a>,
00430                  reginfo-&gt;<a class="code" href="structnetsnmp__handler__registration__s.html#o3">rootoid_len</a>));
00431     DEBUGMSG((<span class="stringliteral">"helper:cache_handler"</span>, <span class="stringliteral">"\n"</span>));
00432 
00433     netsnmp_assert(handler-&gt;<a class="code" href=
"structnetsnmp__mib__handler__s.html#o2">flags</a> &amp; MIB_HANDLER_AUTO_NEXT);
00434 
00435     cache = (netsnmp_cache *) handler-&gt;<a class="code" href="structnetsnmp__mib__handler__s.html#o1">myvoid</a>;
00436     <span class="keywordflow">if</span> (netsnmp_ds_get_boolean(NETSNMP_DS_APPLICATION_ID,
00437                                NETSNMP_DS_AGENT_NO_CACHING) ||
00438         !cache || !cache-&gt;enabled || !cache-&gt;load_cache) {
00439         DEBUGMSG((<span class="stringliteral">"helper:cache_handler"</span>, <span class=
"stringliteral">" caching disabled or "</span>
00440                   <span class="stringliteral">"cache not found, disabled or had no load method\n"</span>));
00441         <span class="keywordflow">return</span> SNMP_ERR_NOERROR;
00442     }
00443 
00444     <span class="comment">/*</span>
00445 <span class="comment">     * Make the handler-chain parameters available to</span>
00446 <span class="comment">     * the cache_load hook routine.</span>
00447 <span class="comment">     */</span>
00448     cache_hint.handler = handler;
00449     cache_hint.reginfo = reginfo;
00450     cache_hint.reqinfo = reqinfo;
00451     cache_hint.requests = requests;
00452     cache-&gt;cache_hint = &amp;cache_hint;
00453 
00454     <span class="keywordflow">switch</span> (reqinfo-&gt;<a class="code" href=
"structnetsnmp__agent__request__info__s.html#o0">mode</a>) {
00455 
00456     <span class="keywordflow">case</span> MODE_GET:
00457     <span class="keywordflow">case</span> MODE_GETNEXT:
00458     <span class="keywordflow">case</span> MODE_GETBULK:
00459     <span class="keywordflow">case</span> MODE_SET_RESERVE1: {
00460 
00461         <span class="comment">/*</span>
00462 <span class="comment">         * only touch cache once per pdu request, to prevent a cache</span>
00463 <span class="comment">         * reload while a module is using cached data.</span>
00464 <span class="comment">         *</span>
00465 <span class="comment">         * XXX: this won't catch a request reloading the cache while</span>
00466 <span class="comment">         * a previous (delegated) request is still using the cache.</span>
00467 <span class="comment">         * maybe use a reference counter?</span>
00468 <span class="comment">         */</span>
00469         <span class="keywordflow">if</span> (<a class="code" href=
"group__cache__handler.html#ga16">netsnmp_cache_is_valid</a>(reqinfo, reginfo-&gt;<a class="code" href=
"structnetsnmp__handler__registration__s.html#o0">handlerName</a>))
00470             <span class="keywordflow">return</span> SNMP_ERR_NOERROR;
00471 
00472         <span class="comment">/*</span>
00473 <span class="comment">         * call the load hook, and update the cache timestamp.</span>
00474 <span class="comment">         * If it's not already there, add to reqinfo</span>
00475 <span class="comment">         */</span>
00476         <a class="code" href="group__cache__handler.html#ga15">netsnmp_cache_check_and_reload</a>(cache);
00477         <a class="code" href=
"group__cache__handler.html#ga11">netsnmp_cache_reqinfo_insert</a>(cache, reqinfo, reginfo-&gt;<a class="code" href=
"structnetsnmp__handler__registration__s.html#o0">handlerName</a>);
00479         }
00480         <span class="keywordflow">return</span> SNMP_ERR_NOERROR;
00481 
00482     <span class="keywordflow">case</span> MODE_SET_RESERVE2:
00483     <span class="keywordflow">case</span> MODE_SET_FREE:
00484     <span class="keywordflow">case</span> MODE_SET_ACTION:
00485     <span class="keywordflow">case</span> MODE_SET_UNDO:
00486         netsnmp_assert(<a class="code" href=
"group__cache__handler.html#ga16">netsnmp_cache_is_valid</a>(reqinfo, reginfo-&gt;<a class="code" href=
"structnetsnmp__handler__registration__s.html#o0">handlerName</a>));
00488         <span class="keywordflow">return</span> SNMP_ERR_NOERROR;
00489 
00490         <span class="comment">/*</span>
00491 <span class="comment">         * A (successful) SET request wouldn't typically trigger a reload of</span>
00492 <span class="comment">         *  the cache, but might well invalidate the current contents.</span>
00493 <span class="comment">         * Only do this on the last pass through.</span>
00494 <span class="comment">         */</span>
00495     <span class="keywordflow">case</span> MODE_SET_COMMIT:
00496         <span class="keywordflow">if</span> (cache-&gt;valid &amp;&amp; 
00497             ! (cache-&gt;flags &amp; NETSNMP_CACHE_DONT_INVALIDATE_ON_SET) ) {
00498             cache-&gt;free_cache(cache, cache-&gt;magic);
00499             cache-&gt;valid = 0;
00500         }
00502         <span class="keywordflow">return</span> SNMP_ERR_NOERROR;
00503 
00504     <span class="keywordflow">default</span>:
00505         <a class="code" href="group__snmp__logging.html#ga41">snmp_log</a>(LOG_WARNING, <span class=
"stringliteral">"cache_handler: Unrecognised mode (%d)\n"</span>,
00506                  reqinfo-&gt;<a class="code" href="structnetsnmp__agent__request__info__s.html#o0">mode</a>);
00507         <a class="code" href="group__snmp__agent.html#ga73">netsnmp_request_set_error_all</a>(requests, SNMP_ERR_GENERR);
00508         <span class="keywordflow">return</span> SNMP_ERR_GENERR;
00509     }
00510     <a class="code" href="group__snmp__agent.html#ga73">netsnmp_request_set_error_all</a>(requests, SNMP_ERR_GENERR);
00511     <span class="keywordflow">return</span> SNMP_ERR_GENERR;     <span class="comment">/* should never get here */</span>
00512 }
00513 
00514 <span class="keyword">static</span> <span class="keywordtype">void</span>
00515 _cache_free( netsnmp_cache *cache )
00516 {
00517     <span class="keywordflow">if</span> (NULL != cache-&gt;free_cache) {
00518         cache-&gt;free_cache(cache, cache-&gt;magic);
00519         cache-&gt;valid = 0;
00520     }
00521 }
00522 
00523 <span class="keyword">static</span> <span class="keywordtype">int</span>
00524 _cache_load( netsnmp_cache *cache )
00525 {
00526     <span class="keywordtype">int</span> ret = -1;
00527 
00528     <span class="comment">/*</span>
00529 <span class="comment">     * If we've got a valid cache, then release it before reloading</span>
00530 <span class="comment">     */</span>
00531     <span class="keywordflow">if</span> (cache-&gt;valid &amp;&amp;
00532         (! (cache-&gt;flags &amp; NETSNMP_CACHE_DONT_FREE_BEFORE_LOAD)))
00533         _cache_free(cache);
00534 
00535     <span class="keywordflow">if</span> ( cache-&gt;load_cache)
00536         ret = cache-&gt;load_cache(cache, cache-&gt;magic);
00537     <span class="keywordflow">if</span> (ret &lt; 0) {
00538         DEBUGMSG((<span class="stringliteral">"helper:cache_handler"</span>, <span class=
"stringliteral">" load failed (%d)\n"</span>,
00539                   ret));
00540         cache-&gt;valid = 0;
00541         <span class="keywordflow">return</span> ret;
00542     }
00543     cache-&gt;valid = 1;
00544     cache-&gt;expired = 0;
00545 
00546     <span class="comment">/*</span>
00547 <span class="comment">     * If we didn't previously have any valid caches outstanding,</span>
00548 <span class="comment">     *   then schedule a pass of the auto-release routine.</span>
00549 <span class="comment">     */</span>
00550     <span class="keywordflow">if</span> ((!cache_outstanding_valid) &amp;&amp;
00551         (! (cache-&gt;flags &amp; NETSNMP_CACHE_DONT_FREE_EXPIRED))) {
00552         <a class="code" href="group__snmp__alarm.html#ga14">snmp_alarm_register</a>(CACHE_RELEASE_FREQUENCY,
00553                             0, release_cached_resources, NULL);
00554         cache_outstanding_valid = 1;
00555     }
00556     <span class="keywordflow">if</span> (cache-&gt;timestamp)
00557         <a class="code" href="group__util.html#ga16">atime_setMarker</a>(cache-&gt;timestamp);
00558     <span class="keywordflow">else</span>
00559         cache-&gt;timestamp = <a class="code" href="group__util.html#ga15">atime_newMarker</a>();
00560     DEBUGMSG((<span class="stringliteral">"helper:cache_handler"</span>, <span class=
"stringliteral">" loaded (%d)\n"</span>,
00561               cache-&gt;timeout));
00562 
00563     <span class="keywordflow">return</span> ret;
00564 }
00565 
00566 
00567 
00575 <span class="keywordtype">void</span>
<a name="l00576" id="l00576"></a><a class="code" href="group__cache__handler.html#ga21">00576</a> <a class="code" href=
"group__cache__handler.html#ga21">release_cached_resources</a>(<span class="keywordtype">unsigned</span> <span class=
"keywordtype">int</span> regNo, <span class="keywordtype">void</span> *clientargs)
00577 {
00578     netsnmp_cache  *cache = NULL;
00579 
00580     cache_outstanding_valid = 0;
00581     DEBUGMSGTL((<span class="stringliteral">"helper:cache_handler"</span>, <span class=
"stringliteral">"running auto-release\n"</span>));
00582     <span class="keywordflow">for</span> (cache = cache_head; cache; cache = cache-&gt;next) {
00583         DEBUGMSGTL((<span class="stringliteral">"helper:cache_handler"</span>,<span class=
"stringliteral">" checking %p (flags 0x%x)\n"</span>,
00584                      cache, cache-&gt;flags));
00585         <span class="keywordflow">if</span> (cache-&gt;valid &amp;&amp;
00586             ! (cache-&gt;flags &amp; NETSNMP_CACHE_DONT_AUTO_RELEASE)) {
00587             DEBUGMSGTL((<span class="stringliteral">"helper:cache_handler"</span>,<span class=
"stringliteral">"  releasing %p\n"</span>, cache));
00588             <span class="comment">/*</span>
00589 <span class="comment">             * Check to see if this cache has timed out.</span>
00590 <span class="comment">             * If so, release the cached resources.</span>
00591 <span class="comment">             * Otherwise, note that we still have at</span>
00592 <span class="comment">             *   least one active cache.</span>
00593 <span class="comment">             */</span>
00594             <span class="keywordflow">if</span> (<a class="code" href=
"group__cache__handler.html#ga14">netsnmp_cache_check_expired</a>(cache)) {
00595                 <span class="keywordflow">if</span>(! (cache-&gt;flags &amp; NETSNMP_CACHE_DONT_FREE_EXPIRED))
00596                     _cache_free(cache);
00597             } <span class="keywordflow">else</span> {
00598                 cache_outstanding_valid = 1;
00599             }
00600         }
00601     }
00602     <span class="comment">/*</span>
00603 <span class="comment">     * If there are any caches still valid &amp; active,</span>
00604 <span class="comment">     *   then schedule another pass.</span>
00605 <span class="comment">     */</span>
00606     <span class="keywordflow">if</span> (cache_outstanding_valid) {
00607         <a class="code" href="group__snmp__alarm.html#ga14">snmp_alarm_register</a>(CACHE_RELEASE_FREQUENCY,
00608                             0, <a class="code" href="group__cache__handler.html#ga21">release_cached_resources</a>, NULL);
00609     }
00610 }
</pre>
  </div>
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  <address style="align: right;">
    <small>Generated on Fri Dec 30 13:47:44 2005 for net-snmp by&nbsp; <a href="http://www.doxygen.org/index.html"><img src=
    "doxygen.png" alt="doxygen" align="middle" border="0" /></a> 1.3.9.1</small>
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