src/health.c

   1 #include "common.h"
   2
   3 // ----------------------------------------------------------------------------
   4 // RRDVAR management
   5
   6 int rrdvar_compare(void* a, void* b) {
   7     if(((RRDVAR *)a)->hash < ((RRDVAR *)b)->hash) return -1;
   8     else if(((RRDVAR *)a)->hash > ((RRDVAR *)b)->hash) return 1;
   9     else return strcmp(((RRDVAR *)a)->name, ((RRDVAR *)b)->name);
  10 }
  11
  12 static inline RRDVAR *rrdvar_index_add(avl_tree_lock *tree, RRDVAR *rv) {
  13     RRDVAR *ret = (RRDVAR *)avl_insert_lock(tree, (avl *)(rv));
  14     if(ret != rv)
  15         debug(D_VARIABLES, "Request to insert RRDVAR '%s' into index failed. Already exists.", rv->name);
  16
  17     return ret;
  18 }
  19
  20 static inline RRDVAR *rrdvar_index_del(avl_tree_lock *tree, RRDVAR *rv) {
  21     RRDVAR *ret = (RRDVAR *)avl_remove_lock(tree, (avl *)(rv));
  22     if(!ret)
  23         fatal("Request to remove RRDVAR '%s' from index failed. Not Found.", rv->name);
  24
  25     return ret;
  26 }
  27
  28 static inline RRDVAR *rrdvar_index_find(avl_tree_lock *tree, const char *name, uint32_t hash) {
  29     RRDVAR tmp;
  30     tmp.name = (char *)name;
  31     tmp.hash = (hash)?hash:simple_hash(tmp.name);
  32
  33     return (RRDVAR *)avl_search_lock(tree, (avl *)&tmp);
  34 }
  35
  36 static inline RRDVAR *rrdvar_create(const char *name, uint32_t hash, int type, calculated_number *value) {
  37     RRDVAR *rv = callocz(1, sizeof(RRDVAR));
  38
  39     rv->name = (char *)name;
  40     rv->hash = (hash)?hash:simple_hash((rv->name));
  41     rv->type = type;
  42     rv->value = value;
  43
  44     return rv;
  45 }
  46
  47 static inline void rrdvar_free(RRDHOST *host, RRDVAR *rv) {
  48     if(host) {
  49         // FIXME: we may need some kind of locking here
  50         // to have mutually exclusive access with eval()
  51         EVAL_VARIABLE *rf;
  52         for (rf = host->references; rf; rf = rf->next)
  53             if (rf->rrdvar == rv) rf->rrdvar = NULL;
  54     }
  55
  56     freez(rv);
  57 }
  58
  59 static inline RRDVAR *rrdvar_create_and_index(const char *scope, avl_tree_lock *tree, const char *name, uint32_t hash, int type, calculated_number *value) {
  60     RRDVAR *rv = rrdvar_index_find(tree, name, hash);
  61     if(unlikely(!rv)) {
  62         debug(D_VARIABLES, "Variable '%s' not found in scope '%s'. Creating a new one.", name, scope);
  63
  64         rv = rrdvar_create(name, hash, type, value);
  65         RRDVAR *ret = rrdvar_index_add(tree, rv);
  66         if(unlikely(ret != rv)) {
  67             debug(D_VARIABLES, "Variable '%s' in scope '%s' already exists", name, scope);
  68             rrdvar_free(NULL, rv);
  69             rv = NULL;
  70         }
  71         else
  72             debug(D_VARIABLES, "Variable '%s' created in scope '%s'", name, scope);
  73     }
  74     else {
  75         // already exists
  76         rv = NULL;
  77     }
  78
  79     /*
  80      * check
  81     if(rv) {
  82         RRDVAR *ret = rrdvar_index_find(tree, name, hash);
  83         if(ret != rv) fatal("oops! 1");
  84
  85         ret = rrdvar_index_del(tree, rv);
  86         if(ret != rv) fatal("oops! 2");
  87
  88         ret = rrdvar_index_add(tree, rv);
  89         if(ret != rv) fatal("oops! 3");
  90     }
  91     */
  92
  93     return rv;
  94 }
  95
  96 // ----------------------------------------------------------------------------
  97 // RRDSETVAR management
  98
  99 #define RRDSETVAR_ID_MAX 1024
 100
 101 RRDSETVAR *rrdsetvar_create(RRDSET *st, const char *variable, int type, void *value, uint32_t options) {
 102     debug(D_VARIABLES, "RRDVARSET create for chart id '%s' name '%s' with variable name '%s'", st->id, st->name, variable);
 103     RRDSETVAR *rs = (RRDSETVAR *)callocz(1, sizeof(RRDSETVAR));
 104
 105     char buffer[RRDSETVAR_ID_MAX + 1];
 106     snprintfz(buffer, RRDSETVAR_ID_MAX, "%s.%s", st->id, variable);
 107     rs->fullid = strdupz(buffer);
 108     rs->hash_fullid = simple_hash(rs->fullid);
 109
 110     snprintfz(buffer, RRDSETVAR_ID_MAX, "%s.%s", st->name, variable);
 111     rs->fullname = strdupz(buffer);
 112     rs->hash_fullname = simple_hash(rs->fullname);
 113
 114     rs->variable = strdupz(variable);
 115     rs->hash_variable = simple_hash(rs->variable);
 116
 117     rs->type = type;
 118     rs->value = value;
 119     rs->options = options;
 120     rs->rrdset = st;
 121
 122     rs->local        = rrdvar_create_and_index("local",   &st->variables_root_index, rs->variable, rs->hash_variable, rs->type, rs->value);
 123     rs->context      = rrdvar_create_and_index("context", &st->rrdcontext->variables_root_index, rs->fullid, rs->hash_fullid, rs->type, rs->value);
 124     rs->host         = rrdvar_create_and_index("host",    &st->rrdhost->variables_root_index, rs->fullid, rs->hash_fullid, rs->type, rs->value);
 125     rs->context_name = rrdvar_create_and_index("context", &st->rrdcontext->variables_root_index, rs->fullname, rs->hash_fullname, rs->type, rs->value);
 126     rs->host_name    = rrdvar_create_and_index("host",    &st->rrdhost->variables_root_index, rs->fullname, rs->hash_fullname, rs->type, rs->value);
 127
 128     rs->next = st->variables;
 129     st->variables = rs;
 130
 131     return rs;
 132 }
 133
 134 void rrdsetvar_rename_all(RRDSET *st) {
 135     debug(D_VARIABLES, "RRDSETVAR rename for chart id '%s' name '%s'", st->id, st->name);
 136
 137     // only these 2 can change name
 138     // rs->context_name
 139     // rs->host_name
 140
 141     char buffer[RRDSETVAR_ID_MAX + 1];
 142     RRDSETVAR *rs, *next = st->variables;
 143     while((rs = next)) {
 144         next = rs->next;
 145
 146         snprintfz(buffer, RRDSETVAR_ID_MAX, "%s.%s", st->name, rs->variable);
 147
 148         if (strcmp(buffer, rs->fullname)) {
 149             // name changed
 150             if (rs->context_name) {
 151                 rrdvar_index_del(&st->rrdcontext->variables_root_index, rs->context_name);
 152                 rrdvar_free(st->rrdhost, rs->context_name);
 153             }
 154
 155             if (rs->host_name) {
 156                 rrdvar_index_del(&st->rrdhost->variables_root_index, rs->host_name);
 157                 rrdvar_free(st->rrdhost, rs->host_name);
 158             }
 159
 160             freez(rs->fullname);
 161             rs->fullname = strdupz(st->name);
 162             rs->hash_fullname = simple_hash(rs->fullname);
 163             rs->context_name = rrdvar_create_and_index("context", &st->rrdcontext->variables_root_index, rs->fullname, rs->hash_fullname, rs->type, rs->value);
 164             rs->host_name    = rrdvar_create_and_index("host",    &st->rrdhost->variables_root_index, rs->fullname, rs->hash_fullname, rs->type, rs->value);
 165         }
 166     }
 167
 168     rrdsetcalc_link_matching(st);
 169 }
 170
 171 void rrdsetvar_free(RRDSETVAR *rs) {
 172     RRDSET *st = rs->rrdset;
 173     debug(D_VARIABLES, "RRDSETVAR free for chart id '%s' name '%s', variable '%s'", st->id, st->name, rs->variable);
 174
 175     if(rs->local) {
 176         rrdvar_index_del(&st->variables_root_index, rs->local);
 177         rrdvar_free(st->rrdhost, rs->local);
 178     }
 179
 180     if(rs->context) {
 181         rrdvar_index_del(&st->rrdcontext->variables_root_index, rs->context);
 182         rrdvar_free(st->rrdhost, rs->context);
 183     }
 184
 185     if(rs->host) {
 186         rrdvar_index_del(&st->rrdhost->variables_root_index, rs->host);
 187         rrdvar_free(st->rrdhost, rs->host);
 188     }
 189
 190     if(rs->context_name) {
 191         rrdvar_index_del(&st->rrdcontext->variables_root_index, rs->context_name);
 192         rrdvar_free(st->rrdhost, rs->context_name);
 193     }
 194
 195     if(rs->host_name) {
 196         rrdvar_index_del(&st->rrdhost->variables_root_index, rs->host_name);
 197         rrdvar_free(st->rrdhost, rs->host_name);
 198     }
 199
 200     if(st->variables == rs) {
 201         st->variables = rs->next;
 202     }
 203     else {
 204         RRDSETVAR *t;
 205         for (t = st->variables; t && t->next != rs; t = t->next);
 206         if(!t) error("RRDSETVAR '%s' not found in chart '%s' variables linked list", rs->fullname, st->id);
 207         else t->next = rs->next;
 208     }
 209
 210     freez(rs->fullid);
 211     freez(rs->fullname);
 212     freez(rs->variable);
 213     freez(rs);
 214 }
 215
 216 // ----------------------------------------------------------------------------
 217 // RRDDIMVAR management
 218
 219 #define RRDDIMVAR_ID_MAX 1024
 220
 221 RRDDIMVAR *rrddimvar_create(RRDDIM *rd, int type, const char *prefix, const char *suffix, void *value, uint32_t options) {
 222     RRDSET *st = rd->rrdset;
 223
 224     debug(D_VARIABLES, "RRDDIMSET create for chart id '%s' name '%s', dimension id '%s', name '%s%s%s'", st->id, st->name, rd->id, (prefix)?prefix:"", rd->name, (suffix)?suffix:"");
 225
 226     if(!prefix) prefix = "";
 227     if(!suffix) suffix = "";
 228
 229     char buffer[RRDDIMVAR_ID_MAX + 1];
 230     RRDDIMVAR *rs = (RRDDIMVAR *)callocz(1, sizeof(RRDDIMVAR));
 231
 232     rs->prefix = strdupz(prefix);
 233     rs->suffix = strdupz(suffix);
 234
 235     snprintfz(buffer, RRDDIMVAR_ID_MAX, "%s%s%s", rs->prefix, rd->id, rs->suffix);
 236     rs->id = strdupz(buffer);
 237     rs->hash = simple_hash(rs->id);
 238
 239     snprintfz(buffer, RRDDIMVAR_ID_MAX, "%s%s%s", rs->prefix, rd->name, rs->suffix);
 240     rs->name = strdupz(buffer);
 241     rs->hash_name = simple_hash(rs->name);
 242
 243     snprintfz(buffer, RRDDIMVAR_ID_MAX, "%s.%s", rd->rrdset->id, rs->id);
 244     rs->fullidid = strdupz(buffer);
 245     rs->hash_fullidid = simple_hash(rs->fullidid);
 246
 247     snprintfz(buffer, RRDDIMVAR_ID_MAX, "%s.%s", rd->rrdset->id, rs->name);
 248     rs->fullidname = strdupz(buffer);
 249     rs->hash_fullidname = simple_hash(rs->fullidname);
 250
 251     snprintfz(buffer, RRDDIMVAR_ID_MAX, "%s.%s", rd->rrdset->name, rs->id);
 252     rs->fullnameid = strdupz(buffer);
 253     rs->hash_fullnameid = simple_hash(rs->fullnameid);
 254
 255     snprintfz(buffer, RRDDIMVAR_ID_MAX, "%s.%s", rd->rrdset->name, rs->name);
 256     rs->fullnamename = strdupz(buffer);
 257     rs->hash_fullnamename = simple_hash(rs->fullnamename);
 258
 259     rs->type = type;
 260     rs->value = value;
 261     rs->options = options;
 262     rs->rrddim = rd;
 263
 264     rs->local_id     = rrdvar_create_and_index("local",   &st->variables_root_index, rs->id, rs->hash, rs->type, rs->value);
 265     rs->local_name   = rrdvar_create_and_index("local",   &st->variables_root_index, rs->name, rs->hash_name, rs->type, rs->value);
 266
 267     rs->context_fullidid     = rrdvar_create_and_index("context", &st->rrdcontext->variables_root_index, rs->fullidid, rs->hash_fullidid, rs->type, rs->value);
 268     rs->context_fullidname   = rrdvar_create_and_index("context", &st->rrdcontext->variables_root_index, rs->fullidname, rs->hash_fullidname, rs->type, rs->value);
 269     rs->context_fullnameid   = rrdvar_create_and_index("context", &st->rrdcontext->variables_root_index, rs->fullnameid, rs->hash_fullnameid, rs->type, rs->value);
 270     rs->context_fullnamename = rrdvar_create_and_index("context", &st->rrdcontext->variables_root_index, rs->fullnamename, rs->hash_fullnamename, rs->type, rs->value);
 271
 272     rs->host_fullidid     = rrdvar_create_and_index("host", &st->rrdhost->variables_root_index, rs->fullidid, rs->hash_fullidid, rs->type, rs->value);
 273     rs->host_fullidname   = rrdvar_create_and_index("host", &st->rrdhost->variables_root_index, rs->fullidname, rs->hash_fullidname, rs->type, rs->value);
 274     rs->host_fullnameid   = rrdvar_create_and_index("host", &st->rrdhost->variables_root_index, rs->fullnameid, rs->hash_fullnameid, rs->type, rs->value);
 275     rs->host_fullnamename = rrdvar_create_and_index("host", &st->rrdhost->variables_root_index, rs->fullnamename, rs->hash_fullnamename, rs->type, rs->value);
 276
 277     rs->next = rd->variables;
 278     rd->variables = rs;
 279
 280     return rs;
 281 }
 282
 283 void rrddimvar_rename_all(RRDDIM *rd) {
 284     RRDSET *st = rd->rrdset;
 285     debug(D_VARIABLES, "RRDDIMSET rename for chart id '%s' name '%s', dimension id '%s', name '%s'", st->id, st->name, rd->id, rd->name);
 286
 287     RRDDIMVAR *rs, *next = rd->variables;
 288     while((rs = next)) {
 289         next = rs->next;
 290
 291         if (strcmp(rd->name, rs->name)) {
 292             char buffer[RRDDIMVAR_ID_MAX + 1];
 293             // name changed
 294
 295             // name
 296             if (rs->local_name) {
 297                 rrdvar_index_del(&st->variables_root_index, rs->local_name);
 298                 rrdvar_free(st->rrdhost, rs->local_name);
 299             }
 300             freez(rs->name);
 301             snprintfz(buffer, RRDDIMVAR_ID_MAX, "%s%s%s", rs->prefix, rd->name, rs->suffix);
 302             rs->name = strdupz(buffer);
 303             rs->hash_name = simple_hash(rs->name);
 304             rs->local_name = rrdvar_create_and_index("local", &st->variables_root_index, rs->name, rs->hash_name, rs->type, rs->value);
 305
 306             // fullidname
 307             if (rs->context_fullidname) {
 308                 rrdvar_index_del(&st->rrdcontext->variables_root_index, rs->context_fullidname);
 309                 rrdvar_free(st->rrdhost, rs->context_fullidname);
 310             }
 311             if (rs->host_fullidname) {
 312                 rrdvar_index_del(&st->rrdhost->variables_root_index, rs->context_fullidname);
 313                 rrdvar_free(st->rrdhost, rs->host_fullidname);
 314             }
 315             freez(rs->fullidname);
 316             snprintfz(buffer, RRDDIMVAR_ID_MAX, "%s.%s", st->id, rs->name);
 317             rs->fullidname = strdupz(buffer);
 318             rs->hash_fullidname = simple_hash(rs->fullidname);
 319             rs->context_fullidname = rrdvar_create_and_index("context", &st->rrdcontext->variables_root_index,
 320                                                              rs->fullidname, rs->hash_fullidname, rs->type, rs->value);
 321             rs->host_fullidname = rrdvar_create_and_index("host", &st->rrdhost->variables_root_index,
 322                                                              rs->fullidname, rs->hash_fullidname, rs->type, rs->value);
 323
 324             // fullnameid
 325             if (rs->context_fullnameid) {
 326                 rrdvar_index_del(&st->rrdcontext->variables_root_index, rs->context_fullnameid);
 327                 rrdvar_free(st->rrdhost, rs->context_fullnameid);
 328             }
 329             if (rs->host_fullnameid) {
 330                 rrdvar_index_del(&st->rrdhost->variables_root_index, rs->context_fullnameid);
 331                 rrdvar_free(st->rrdhost, rs->host_fullnameid);
 332             }
 333             freez(rs->fullnameid);
 334             snprintfz(buffer, RRDDIMVAR_ID_MAX, "%s.%s", st->name, rs->id);
 335             rs->fullnameid = strdupz(buffer);
 336             rs->hash_fullnameid = simple_hash(rs->fullnameid);
 337             rs->context_fullnameid = rrdvar_create_and_index("context", &st->rrdcontext->variables_root_index,
 338                                                              rs->fullnameid, rs->hash_fullnameid, rs->type, rs->value);
 339             rs->host_fullnameid = rrdvar_create_and_index("host", &st->rrdhost->variables_root_index,
 340                                                           rs->fullnameid, rs->hash_fullnameid, rs->type, rs->value);
 341
 342             // fullnamename
 343             if (rs->context_fullnamename) {
 344                 rrdvar_index_del(&st->rrdcontext->variables_root_index, rs->context_fullnamename);
 345                 rrdvar_free(st->rrdhost, rs->context_fullnamename);
 346             }
 347             if (rs->host_fullnamename) {
 348                 rrdvar_index_del(&st->rrdhost->variables_root_index, rs->context_fullnamename);
 349                 rrdvar_free(st->rrdhost, rs->host_fullnamename);
 350             }
 351             freez(rs->fullnamename);
 352             snprintfz(buffer, RRDDIMVAR_ID_MAX, "%s.%s", st->name, rs->name);
 353             rs->fullnamename = strdupz(buffer);
 354             rs->hash_fullnamename = simple_hash(rs->fullnamename);
 355             rs->context_fullnamename = rrdvar_create_and_index("context", &st->rrdcontext->variables_root_index,
 356                                                              rs->fullnamename, rs->hash_fullnamename, rs->type, rs->value);
 357             rs->host_fullnamename = rrdvar_create_and_index("host", &st->rrdhost->variables_root_index,
 358                                                           rs->fullnamename, rs->hash_fullnamename, rs->type, rs->value);
 359         }
 360     }
 361 }
 362
 363 void rrddimvar_free(RRDDIMVAR *rs) {
 364     RRDDIM *rd = rs->rrddim;
 365     RRDSET *st = rd->rrdset;
 366     debug(D_VARIABLES, "RRDDIMSET free for chart id '%s' name '%s', dimension id '%s', name '%s', prefix='%s', suffix='%s'", st->id, st->name, rd->id, rd->name, rs->prefix, rs->suffix);
 367
 368     if(rs->local_id) {
 369         rrdvar_index_del(&st->variables_root_index, rs->local_id);
 370         rrdvar_free(st->rrdhost, rs->local_id);
 371     }
 372     if(rs->local_name) {
 373         rrdvar_index_del(&st->variables_root_index, rs->local_name);
 374         rrdvar_free(st->rrdhost, rs->local_name);
 375     }
 376
 377     if(rs->context_fullidid) {
 378         rrdvar_index_del(&st->rrdcontext->variables_root_index, rs->context_fullidid);
 379         rrdvar_free(st->rrdhost, rs->context_fullidid);
 380     }
 381     if(rs->context_fullidname) {
 382         rrdvar_index_del(&st->rrdcontext->variables_root_index, rs->context_fullidname);
 383         rrdvar_free(st->rrdhost, rs->context_fullidname);
 384     }
 385     if(rs->context_fullnameid) {
 386         rrdvar_index_del(&st->rrdcontext->variables_root_index, rs->context_fullnameid);
 387         rrdvar_free(st->rrdhost, rs->context_fullnameid);
 388     }
 389     if(rs->context_fullnamename) {
 390         rrdvar_index_del(&st->rrdcontext->variables_root_index, rs->context_fullnamename);
 391         rrdvar_free(st->rrdhost, rs->context_fullnamename);
 392     }
 393
 394     if(rs->host_fullidid) {
 395         rrdvar_index_del(&st->rrdhost->variables_root_index, rs->host_fullidid);
 396         rrdvar_free(st->rrdhost, rs->host_fullidid);
 397     }
 398     if(rs->host_fullidname) {
 399         rrdvar_index_del(&st->rrdhost->variables_root_index, rs->host_fullidname);
 400         rrdvar_free(st->rrdhost, rs->host_fullidname);
 401     }
 402     if(rs->host_fullnameid) {
 403         rrdvar_index_del(&st->rrdhost->variables_root_index, rs->host_fullnameid);
 404         rrdvar_free(st->rrdhost, rs->host_fullnameid);
 405     }
 406     if(rs->host_fullnamename) {
 407         rrdvar_index_del(&st->rrdhost->variables_root_index, rs->host_fullnamename);
 408         rrdvar_free(st->rrdhost, rs->host_fullnamename);
 409     }
 410
 411     if(rd->variables == rs) {
 412         debug(D_VARIABLES, "RRDDIMSET removing first entry for chart id '%s' name '%s', dimension id '%s', name '%s'", st->id, st->name, rd->id, rd->name);
 413         rd->variables = rs->next;
 414     }
 415     else {
 416         debug(D_VARIABLES, "RRDDIMSET removing non-first entry for chart id '%s' name '%s', dimension id '%s', name '%s'", st->id, st->name, rd->id, rd->name);
 417         RRDDIMVAR *t;
 418         for (t = rd->variables; t && t->next != rs; t = t->next) ;
 419         if(!t) error("RRDDIMVAR '%s' not found in dimension '%s/%s' variables linked list", rs->name, st->id, rd->id);
 420         else t->next = rs->next;
 421     }
 422
 423     freez(rs->prefix);
 424     freez(rs->suffix);
 425     freez(rs->id);
 426     freez(rs->name);
 427     freez(rs->fullidid);
 428     freez(rs->fullidname);
 429     freez(rs->fullnameid);
 430     freez(rs->fullnamename);
 431     freez(rs);
 432 }
 433
 434 // ----------------------------------------------------------------------------
 435 // RRDCALC management
 436
 437 // this has to be called while the caller has locked
 438 // the RRDHOST
 439 static inline void rrdhostcalc_linked(RRDHOST *host, RRDCALC *rc) {
 440     // move it to be last
 441
 442     if(!rc->next)
 443         // we are last already
 444         return;
 445
 446     RRDCALC *t, *last = NULL, *prev = NULL;
 447     for (t = host->calculations; t ; t = t->next) {
 448         if(t->next == rc)
 449             prev = t;
 450
 451         if(!t->next)
 452             last = t;
 453     }
 454
 455     if(!last) {
 456         error("RRDCALC '%s' cannot be linked to the end of host '%s' list", rc->name, host->hostname);
 457         return;
 458     }
 459
 460     if(prev)
 461         prev->next = rc->next;
 462     else {
 463         if(host->calculations == rc)
 464             host->calculations = rc->next;
 465         else {
 466             error("RRDCALC '%s' is not found in host '%s' list", rc->name, host->hostname);
 467             return;
 468         }
 469     }
 470
 471     last->next = rc;
 472     rc->next = NULL;
 473 }
 474
 475 // this has to be called while the caller has locked
 476 // the RRDHOST
 477 static inline void rrdhostcalc_unlinked(RRDHOST *host, RRDCALC *rc) {
 478     // move it to be first
 479
 480     if(host->calculations == rc) {
 481         // ok, we are the first
 482         return;
 483     }
 484     else {
 485         // find the previous one
 486         RRDCALC *t;
 487         for (t = host->calculations; t && t->next != rc; rc = rc->next) ;
 488         if(unlikely(!t)) {
 489             error("RRDCALC '%s' is not linked to host '%s'.", rc->name, host->hostname);
 490             return;
 491         }
 492         t->next = rc->next;
 493         rc->next = host->calculations;
 494         host->calculations = rc;
 495     }
 496 }
 497
 498 static void rrdsetcalc_link(RRDSET *st, RRDCALC *rc) {
 499     rc->rrdset = st;
 500
 501     rc->local   = rrdvar_create_and_index("local", &st->variables_root_index, rc->name, rc->hash, RRDVAR_TYPE_CALCULATED, &rc->value);
 502     rc->context = rrdvar_create_and_index("context", &st->rrdcontext->variables_root_index, rc->name, rc->hash, RRDVAR_TYPE_CALCULATED, &rc->value);
 503     rc->host    = rrdvar_create_and_index("host", &st->rrdhost->variables_root_index, rc->name, rc->hash, RRDVAR_TYPE_CALCULATED, &rc->value);
 504
 505     rrdhostcalc_linked(st->rrdhost, rc);
 506 }
 507
 508 // this has to be called while the RRDHOST is locked
 509 void rrdsetcalc_link_matching(RRDSET *st) {
 510     RRDCALC *rc;
 511
 512     for(rc = st->rrdhost->calculations; rc ; rc = rc->next) {
 513         // since unlinked ones are in front and linked at the end
 514         // we stop on the first linked RRDCALC
 515         if(rc->rrdset != NULL) break;
 516
 517         if((rc->hash_chart == st->hash && !strcmp(rc->name, st->id)) ||
 518                 (rc->hash_chart == st->hash_name && !strcmp(rc->name, st->name))) {
 519             rrdsetcalc_link(st, rc);
 520         }
 521     }
 522 }
 523
 524 // this has to be called while the RRDHOST is locked
 525 void rrdsetcalc_unlink(RRDCALC *rc) {
 526     RRDSET *st = rc->rrdset;
 527
 528     if(!st) {
 529         error("Requested to unlink RRDCALC '%s' which is not linked to any RRDSET", rc->name);
 530         return;
 531     }
 532
 533     RRDHOST *host = st->rrdhost;
 534
 535     // unlink it
 536     if(rc->rrdset_prev)
 537         rc->rrdset_prev->rrdset_next = rc->rrdset_next;
 538
 539     if(rc->rrdset_next)
 540         rc->rrdset_next->rrdset_prev = rc->rrdset_prev;
 541
 542     if(st->calculations == rc)
 543         st->calculations = rc->rrdset_next;
 544
 545     rc->rrdset_prev = rc->rrdset_next = NULL;
 546
 547     if(rc->local) {
 548         rrdvar_index_del(&st->variables_root_index, rc->local);
 549         rrdvar_free(st->rrdhost, rc->local);
 550         rc->local = NULL;
 551     }
 552
 553     if(rc->context) {
 554         rrdvar_index_del(&st->rrdcontext->variables_root_index, rc->context);
 555         rc->context = NULL;
 556     }
 557
 558     if(rc->host) {
 559         rrdvar_index_del(&st->rrdhost->variables_root_index, rc->host);
 560         rc->host = NULL;
 561     }
 562
 563     rc->rrdset = NULL;
 564
 565     // RRDCALC will remain in RRDHOST
 566     // so that if the matching chart is found in the future
 567     // it will be applied automatically
 568
 569     rrdhostcalc_unlinked(host, rc);
 570 }
 571
 572 RRDCALC *rrdcalc_create(RRDHOST *host, const char *name, const char *chart, const char *dimensions, int group_method, uint32_t after, uint32_t before, int update_every, uint32_t options) {
 573     uint32_t hash = simple_hash(name);
 574
 575     RRDCALC *rc;
 576
 577     // make sure it does not already exist
 578     for(rc = host->calculations; rc ; rc = rc->next) {
 579         if (rc->hash == hash && !strcmp(name, rc->name)) {
 580             error("Attempted to create RRDCAL '%s' in host '%s', but it already exists. Ignoring it.", name, host->hostname);
 581             return NULL;
 582         }
 583     }
 584
 585     rc = callocz(1, sizeof(RRDCALC));
 586
 587     rc->name = strdupz(name);
 588     rc->hash = simple_hash(rc->name);
 589
 590     rc->chart = strdupz(chart);
 591     rc->hash_chart = simple_hash(rc->chart);
 592
 593     if(dimensions) {
 594         rc->dimensions = strdupz(dimensions);
 595         rc->hash_chart = simple_hash(rc->chart);
 596     }
 597
 598     return NULL;
 599 }
 600
 601 void rrdcalc_free(RRDCALC *rc) {
 602     if(!rc) return;
 603
 604     if(rc->rrdset) rrdsetcalc_unlink(rc);
 605
 606     freez(rc);
 607 }