src/nobug_resources.c

   1 /*
   2  This file is part of the NoBug debugging library.
   3
   4  Copyright (C) 2007, 2008, 2009, Christian Thaeter <ct@pipapo.org>
   5
   6  This program is free software; you can redistribute it and/or modify
   7  it under the terms of the GNU General Public License as published by
   8  the Free Software Foundation; either version 2 of the License, or
   9  (at your option) any later version.
  10
  11  This program is distributed in the hope that it will be useful,
  12  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  GNU General Public License for more details.
  15
  16  You should have received a copy of the GNU General Public License
  17  along with this program; if not, contact Christian Thaeter <ct@pipapo.org>.
  18 */
  19 #include <stdlib.h>
  20
  21 #define NOBUG_LIBNOBUG_C
  22 #include "nobug.h"
  23 #include "llist.h"
  24 #include "mpool.h"
  25
  26 /*
  27 //deadlock There are 2 kinds of nodes: `resource_record` hold registered resources and `resource_user` which
  28 //deadlock attach to (enter) a resource.
  29 //deadlock
  30 //deadlock Each thread keeps stacklist of each `resource_user` it created, new enters will push on the stack,
  31 //deadlock leaving a resource will remove it from this stacklist.
  32 //deadlock
  33 //deadlock All `resource_records` in use are linked in a global precedence list, items of equal precedence are
  34 //deadlock spaned by a skip pointer. Whenever a resource is entered the deadlock checker asserts that one does
  35 //deadlock not break existing precedences. By doing so the precedence list gets continously refined as the system
  36 //deadlock learns about new lock patterns.
  37 //deadlock
  38 //deadlock As a consequence of this algorithm the deadlock checker does not only find real deadlocks but
  39 //deadlock already potential deadlocks by violations of the locking order which is a lot simpler than finding
  40 //deadlock actual deadlocks.
  41 //deadlock
  42 //deadlock This also means that the deadlock tracker currently only works with hierarchical locking policies
  43 //deadlock other approaches to prevent deadlocks are not yet supported and will be added on demand.
  44 //deadlock
  45 //deadlock
  46 //deadlock
  47 */
  48
  49 /*
  50   How much memory to reserve for a mpool chunk, 16k by default
  51  */
  52 #ifndef NOBUG_RESOURCE_MPOOL_CHUNKSIZE
  53 #define NOBUG_RESOURCE_MPOOL_CHUNKSIZE (4096<<(sizeof(void*)/4))        /* That is roughly 8k chunks on 32bit, 16k chunks on 64 bit machines */
  54 #endif
  55
  56 #if NOBUG_USE_PTHREAD
  57 pthread_mutex_t nobug_resource_mutex = PTHREAD_MUTEX_INITIALIZER;
  58 #define NOBUG_RESOURCE_LOCK pthread_mutex_lock (&nobug_resource_mutex)
  59 #define NOBUG_RESOURCE_UNLOCK pthread_mutex_unlock (&nobug_resource_mutex)
  60 #else
  61 #define NOBUG_RESOURCE_LOCK
  62 #define NOBUG_RESOURCE_UNLOCK
  63 #endif
  64
  65 #define nobug_resourcestates    \
  66   resource_state(invalid),      \
  67   resource_state(waiting),      \
  68   resource_state(exclusive),    \
  69   resource_state(recursive),    \
  70   resource_state(shared),
  71
  72
  73 #define resource_state(name) #name
  74 const char* nobug_resource_states[] =
  75   {
  76     nobug_resourcestates
  77     NULL
  78   };
  79 #undef resource_state
  80
  81 const char* nobug_resource_error = NULL;
  82
  83 static llist nobug_resource_registry;
  84 static mpool nobug_resource_record_pool;
  85 static mpool nobug_resource_user_pool;
  86 #if NOBUG_USE_PTHREAD
  87 static mpool nobug_resource_node_pool;
  88 #endif
  89
  90 static void nobug_resource_record_dtor (void*);
  91 static void nobug_resource_user_dtor (void*);
  92 #if NOBUG_USE_PTHREAD
  93 static void nobug_resource_node_dtor (void*);
  94 #endif
  95
  96
  97 void
  98 nobug_resource_init (void)
  99 {
 100   llist_init (&nobug_resource_registry);
 101
 102   mpool_init (&nobug_resource_record_pool,
 103               sizeof(struct nobug_resource_record),
 104               NOBUG_RESOURCE_MPOOL_CHUNKSIZE/sizeof(struct nobug_resource_record),
 105               nobug_resource_record_dtor);
 106
 107   mpool_init (&nobug_resource_user_pool,
 108               sizeof(struct nobug_resource_user),
 109               NOBUG_RESOURCE_MPOOL_CHUNKSIZE/sizeof(struct nobug_resource_user),
 110               nobug_resource_user_dtor);
 111
 112 #if NOBUG_USE_PTHREAD
 113   mpool_init (&nobug_resource_node_pool,
 114               sizeof(struct nobug_resource_node),
 115               NOBUG_RESOURCE_MPOOL_CHUNKSIZE/sizeof(struct nobug_resource_node),
 116               nobug_resource_node_dtor);
 117 #endif
 118 }
 119
 120
 121 void
 122 nobug_resource_destroy (void)
 123 {
 124 #if NOBUG_USE_PTHREAD
 125   mpool_destroy (&nobug_resource_node_pool);
 126 #endif
 127   mpool_destroy (&nobug_resource_user_pool);
 128   mpool_destroy (&nobug_resource_record_pool);
 129 }
 130
 131
 132 unsigned
 133 nobug_resource_record_available (void)
 134 {
 135   return mpool_available (&nobug_resource_record_pool);
 136 }
 137
 138
 139 unsigned
 140 nobug_resource_user_available (void)
 141 {
 142   return mpool_available (&nobug_resource_user_pool);
 143 }
 144
 145
 146 #if NOBUG_USE_PTHREAD
 147 unsigned
 148 nobug_resource_node_available (void)
 149 {
 150   return mpool_available (&nobug_resource_node_pool);
 151 }
 152
 153
 154 static void
 155 nobug_resource_node_free (struct nobug_resource_node* self)
 156 {
 157   LLIST_WHILE_HEAD (&self->childs, c)
 158     nobug_resource_node_free (LLIST_TO_STRUCTP(c, struct nobug_resource_node, cldnode));
 159
 160   llist_unlink_fast_ (&self->cldnode);
 161   llist_unlink_fast_ (&self->node);
 162   mpool_free (&nobug_resource_node_pool, self);
 163 }
 164
 165
 166 static void
 167 nobug_resource_node_dtor (void* p)
 168 {
 169   struct nobug_resource_node* n = p;
 170   llist_unlink_fast_ (&n->node);
 171   /* must unlink childs, because we don't destroy the tree bottom up */
 172   llist_unlink_fast_ (&n->childs);
 173   llist_unlink_fast_ (&n->cldnode);
 174 }
 175 #endif
 176
 177
 178 static void
 179 nobug_resource_record_dtor (void* p)
 180 {
 181   struct nobug_resource_record* self= p;
 182   llist_unlink_fast_ (&self->hdr.node);
 183
 184 #if NOBUG_USE_PTHREAD
 185   /* destroy all nodes recursively */
 186   LLIST_WHILE_HEAD (&self->nodes, n)
 187     nobug_resource_node_free ((struct nobug_resource_node*)n);
 188 #endif
 189 }
 190
 191
 192 static void
 193 nobug_resource_user_dtor (void* p)
 194 {
 195   struct nobug_resource_user* u = p;
 196   llist_unlink_fast_ (&u->hdr.node);
 197 #if NOBUG_USE_PTHREAD
 198   llist_unlink_fast_ (&u->res_stack);
 199 #endif
 200 }
 201
 202
 203 static int
 204 compare_resource_records (const_LList av, const_LList bv, void* unused)
 205 {
 206   (void) unused;
 207   const struct nobug_resource_record* a = (const struct nobug_resource_record*)av;
 208   const struct nobug_resource_record* b = (const struct nobug_resource_record*)bv;
 209
 210   return a->object_id > b->object_id ? 1 : a->object_id < b->object_id ? -1 : 0;
 211 }
 212
 213
 214 struct nobug_resource_record*
 215 nobug_resource_announce (const char* type, const char* name, const void* object_id, const char* extra)
 216 {
 217   NOBUG_RESOURCE_LOCK;
 218
 219   struct nobug_resource_record* node = mpool_alloc (&nobug_resource_record_pool);
 220   if (!node)
 221     {
 222       nobug_resource_error = "internal allocation error";
 223       return NULL;
 224     }
 225
 226   node->hdr.name = name;
 227   node->object_id = object_id;
 228   node->type = type;
 229
 230   /* TODO better lookup method than list search (psplay?) */
 231   if (llist_ufind (&nobug_resource_registry, &node->hdr.node, compare_resource_records, NULL))
 232     {
 233       nobug_resource_error = "already registered";
 234       return NULL;
 235     }
 236
 237   llist_init (&node->users);
 238   node->hdr.extra = extra;
 239 #if NOBUG_USE_PTHREAD
 240   llist_init (&node->nodes);
 241 #endif
 242
 243   llist_insert_head (&nobug_resource_registry, llist_init (&node->hdr.node));
 244
 245   NOBUG_RESOURCE_UNLOCK;
 246   return node;
 247 }
 248
 249
 250 int
 251 nobug_resource_forget (struct nobug_resource_record* self)
 252 {
 253   NOBUG_RESOURCE_LOCK;
 254   if (!llist_find (&nobug_resource_registry, &self->hdr.node, compare_resource_records, NULL))
 255     {
 256       nobug_resource_error = "not registered";
 257       return 0;
 258     }
 259
 260   if (!llist_is_empty (&self->users))
 261     {
 262       nobug_resource_error = "still in use";
 263       return 0;
 264     }
 265
 266   nobug_resource_record_dtor (self);
 267
 268   mpool_free (&nobug_resource_record_pool, self);
 269   NOBUG_RESOURCE_UNLOCK;
 270   return 1;
 271 }
 272
 273
 274 #if NOBUG_USE_PTHREAD
 275 static int
 276 nobug_resource_node_resource_cmpfn (const_LList a, const_LList b, void* extra)
 277 {
 278   (void) extra;
 279   return ((struct nobug_resource_node*)a)->resource ==
 280     ((struct nobug_resource_node*)b)->resource?0:-1;
 281 }
 282
 283
 284 struct nobug_resource_node*
 285 nobug_resource_node_new (struct nobug_resource_record* resource,
 286                          struct nobug_resource_node* parent)
 287 {
 288   struct nobug_resource_node* self = mpool_alloc (&nobug_resource_node_pool);
 289   if (self)
 290     {
 291       llist_insert_head (&resource->nodes, llist_init (&self->node));
 292       self->resource = resource;
 293
 294       self->parent = parent;
 295
 296       llist_init (&self->childs);
 297       llist_init (&self->cldnode);
 298       if (parent)
 299         llist_insert_head (&parent->childs, &self->cldnode);
 300     }
 301   return self;
 302 }
 303 #endif
 304
 305
 306 //dlalgo HEAD~ The Resource Tracking Algorithm; deadlock_detection; how resources are tracked
 307 //dlalgo
 308 //dlalgo Each resource registers a global 'resource_record'.
 309 //dlalgo
 310 //dlalgo Every new locking path discovered is stored as 'resource_node' structures which refer to the associated
 311 //dlalgo 'resource_record'.
 312 //dlalgo
 313 //dlalgo Threads keep a trail of 'resource_user' strcutures for each resource entered. This 'resource_user' struct
 314 //dlalgo refer to the 'resource_nodes' and thus indirectly to the associated 'resource_record'.
 315 //dlalgo
 316 //dlalgo The deadlock checker uses this information to test if the acqusition of a new resource would yield a
 317 //dlalgo potential deadlock.
 318 //dlalgo
 319 struct nobug_resource_user*
 320 nobug_resource_enter (struct nobug_resource_record* resource,
 321                       const char* identifier,
 322                       enum nobug_resource_state state,
 323                       const char* extra)
 324 {
 325   NOBUG_RESOURCE_LOCK;
 326
 327   if (!resource)
 328     {
 329       nobug_resource_error = "no resource";
 330       return NULL;
 331     }
 332
 333 #if NOBUG_USE_PTHREAD
 334   struct nobug_tls_data* tls = nobug_thread_get ();
 335
 336   //dlalgo HEAD^ Entering Resources; nobug_resource_enter; deadlock check on enter
 337   //dlalgo
 338   //dlalgo In multithreaded programs, whenever a thread wants to wait for a 'resource_record'
 339   //dlalgo the deadlock checker jumps in.
 340   //dlalgo
 341   //dlalgo The deadlock checking algorithm is anticipatory as it will find and abort on conditions which may lead
 342   //dlalgo to a potential deadlock by violating the locking order learned earlier.
 343   //dlalgo
 344   //dlalgo Each thread holds a stack (list) of each 'resource_user' it created. Leaving
 345   //dlalgo a resource will remove it from this stacklist.
 346   //dlalgo
 347   //dlalgo Each 'resource_record' stores the trail which other 'resource_records' are already entered. This relations
 348   //dlalgo are implemented with the 'resource_node' helper structure.
 349   //dlalgo
 350   //dlalgo ////
 351   //dlalgo TODO: insert diagram here
 352   //dlalgo   2-3
 353   //dlalgo 1
 354   //dlalgo   3-4-2
 355   //dlalgo
 356   //dlalgo 1-3-2-4
 357   //dlalgo
 358   //dlalgo 3-4-2
 359   //dlalgo
 360   //dlalgo 1-4-2
 361   //dlalgo
 362   //dlalgo ////
 363   //dlalgo
 364   //dlalgo First we find out if there is already a node from the to be acquired resource back to
 365   //dlalgo the topmost node of the current threads user stack.
 366   //dlalgo
 367   //dlalgo [source,c]
 368   //dlalgo ---------------------------------------------------------------------
 369   struct nobug_resource_user* user = NULL;                      //dlalgo VERBATIM
 370   struct nobug_resource_node* node = NULL;                      //dlalgo VERBATIM
 371                                                                 //dlalgo VERBATIM
 372   if (!llist_is_empty (&tls->res_stack))                        //dlalgo VERBATIM
 373     {                                                           //dlalgo VERBATIM
 374       user = LLIST_TO_STRUCTP (llist_tail (&tls->res_stack),    //dlalgo VERBATIM
 375                                struct nobug_resource_user,      //dlalgo VERBATIM
 376                                res_stack);                      //dlalgo VERBATIM
 377                                                                 //dlalgo VERBATIM
 378       struct nobug_resource_node templ =                        //dlalgo VERBATIM
 379         {                                                       //dlalgo VERBATIM
 380           {NULL, NULL},                                         //dlalgo          ...
 381           user->current->resource,                              //dlalgo VERBATIM
 382           NULL,                                                 //dlalgo          ...
 383           {NULL, NULL},
 384           {NULL, NULL}
 385         };                                                      //dlalgo VERBATIM
 386                                                                 //dlalgo VERBATIM
 387       node = (struct nobug_resource_node*)                      //dlalgo VERBATIM
 388         llist_ufind (&resource->nodes,                          //dlalgo VERBATIM
 389                      &templ.node,                               //dlalgo VERBATIM
 390                      nobug_resource_node_resource_cmpfn,        //dlalgo VERBATIM
 391                      NULL);                                     //dlalgo VERBATIM
 392     }                                                           //dlalgo VERBATIM
 393   //dlalgo   ...
 394   //dlalgo ---------------------------------------------------------------------
 395   //dlalgo
 396 #endif
 397
 398   //dlalgo Deadlock checking is only done when the node is entered in `WAITING` state and only
 399   //dlalgo available in multithreaded programs.
 400   //dlalgo
 401   //dlalgo [source,c]
 402   //dlalgo ---------------------------------------------------------------------
 403   if (state == NOBUG_RESOURCE_WAITING)                          //dlalgo VERBATIM
 404     {                                                           //dlalgo VERBATIM
 405 #if NOBUG_USE_PTHREAD                                           //dlalgo VERBATIM
 406       //dlalgo       ...
 407       //dlalgo ---------------------------------------------------------------------
 408       //dlalgo
 409
 410       //dlalgo If node was found above, then this locking path is already validated and no deadlock can happen,
 411       //dlalgo else, if this stack already holds a resource (user is set) we have to go on with checking.
 412       //dlalgo
 413       //dlalgo [source,c]
 414       //dlalgo ---------------------------------------------------------------------
 415       if (!node && user)                                                //dlalgo VERBATIM
 416         {                                                               //dlalgo VERBATIM
 417           //dlalgo           ...
 418           //dlalgo ---------------------------------------------------------------------
 419           //dlalgo
 420           //dlalgo If not then its checked that the resource to be entered is not on any parent trail of the current topmost resource,
 421           //dlalgo if it is then this could be a deadlock which needs to be further investigated.
 422           //dlalgo
 423           //dlalgo [source,c]
 424           //dlalgo ---------------------------------------------------------------------
 425           LLIST_FOREACH (&user->current->resource->nodes, n)            //dlalgo VERBATIM
 426             {                                                           //dlalgo VERBATIM
 427               for (struct nobug_resource_node* itr =                    //dlalgo VERBATIM
 428                      ((struct nobug_resource_node*)n)->parent;          //dlalgo VERBATIM
 429                    itr;                                                 //dlalgo VERBATIM
 430                    itr = itr->parent)                                   //dlalgo VERBATIM
 431                 {                                                       //dlalgo VERBATIM
 432                   if (itr->resource == resource)                        //dlalgo VERBATIM
 433                     {                                                   //dlalgo VERBATIM
 434                       //dlalgo                       ...
 435                       //dlalgo ---------------------------------------------------------------------
 436                       //dlalgo
 437                       //dlalgo if the resource was on the trail, we search if there is a common ancestor before the resource
 438                       //dlalgo on the trail and the threads current chain,
 439                       //dlalgo if yes then this ancestor protects against deadlocks and we can continue.
 440                       //dlalgo
 441                       //dlalgo [source,c]
 442                       //dlalgo ---------------------------------------------------------------------
 443                       for (struct nobug_resource_node* itr2 = itr->parent;              //dlalgo VERBATIM
 444                            itr2;                                                        //dlalgo VERBATIM
 445                            itr2 = itr2->parent)                                         //dlalgo VERBATIM
 446                         {                                                               //dlalgo VERBATIM
 447                           LLIST_FOREACH_REV (&tls->res_stack, p)                        //dlalgo VERBATIM
 448                             {                                                           //dlalgo VERBATIM
 449                               struct nobug_resource_user* user =                        //dlalgo VERBATIM
 450                                 LLIST_TO_STRUCTP (p,                                    //dlalgo VERBATIM
 451                                                   struct nobug_resource_user,           //dlalgo VERBATIM
 452                                                   res_stack);                           //dlalgo VERBATIM
 453                               if (user->current->resource == itr2->resource)            //dlalgo VERBATIM
 454                                 goto done;                                              //dlalgo VERBATIM
 455                             }                                                           //dlalgo VERBATIM
 456                           //dlalgo ---------------------------------------------------------------------
 457                           //dlalgo
 458                           //dlalgo If no ancestor found, we finally abort with a potential deadlock condition.
 459                           //dlalgo
 460                           //dlalgo [source,c]
 461                           //dlalgo ---------------------------------------------------------------------
 462                           nobug_resource_error = "possible deadlock detected";          //dlalgo VERBATIM
 463                           return NULL;                                                  //dlalgo VERBATIM
 464                           //dlalgo                           ...
 465                           //dlalgo ---------------------------------------------------------------------
 466                           //dlalgo
 467                         }
 468                     }
 469                 }
 470             }
 471         }
 472     done:;
 473 #endif
 474     }
 475   else if (state == NOBUG_RESOURCE_EXCLUSIVE)
 476     {
 477       /* check that everyone is waiting */
 478       LLIST_FOREACH (&resource->users, n)
 479         if (((struct nobug_resource_user*)n)->state != NOBUG_RESOURCE_WAITING)
 480           {
 481             nobug_resource_error = "invalid enter state (resource already claimed)";
 482             break;
 483           }
 484     }
 485 #if NOBUG_USE_PTHREAD
 486   else if (state == NOBUG_RESOURCE_RECURSIVE)
 487     {
 488       /* check that everyone *else* is waiting */
 489       LLIST_FOREACH (&resource->users, n)
 490         {
 491           struct nobug_resource_user* user = (struct nobug_resource_user*)n;
 492           if (user->state != NOBUG_RESOURCE_WAITING &&
 493               user->thread != tls)
 494             {
 495               nobug_resource_error = "invalid enter state (resource already claimed non recursive by another thread)";
 496               break;
 497             }
 498           else if (!(user->state == NOBUG_RESOURCE_WAITING ||
 499                      user->state == NOBUG_RESOURCE_RECURSIVE) &&
 500                    user->thread == tls)
 501             {
 502               nobug_resource_error = "invalid enter state (resource already claimed non recursive by this thread)";
 503               break;
 504             }
 505         }
 506     }
 507 #endif
 508   else if (state == NOBUG_RESOURCE_SHARED)
 509     {
 510       /* check that every one else is waiting or hold it shared */
 511       LLIST_FOREACH (&resource->users, n)
 512         if (((struct nobug_resource_user*)n)->state != NOBUG_RESOURCE_WAITING
 513             && ((struct nobug_resource_user*)n)->state != NOBUG_RESOURCE_SHARED)
 514           {
 515             nobug_resource_error = "invalid enter state (resource already claimed non shared)";
 516             break;
 517           }
 518     }
 519   else
 520     nobug_resource_error = "invalid enter state";
 521
 522   if (nobug_resource_error)
 523     return NULL;
 524
 525   struct nobug_resource_user* new_user = mpool_alloc (&nobug_resource_user_pool);
 526   if (!new_user)
 527     {
 528       nobug_resource_error = "internal allocation error";
 529       return NULL;
 530     }
 531
 532   new_user->hdr.name = identifier;
 533   new_user->hdr.extra = extra;
 534   new_user->state = state;
 535   llist_insert_head (&resource->users, llist_init (&new_user->hdr.node));
 536
 537 #if NOBUG_USE_PTHREAD
 538   if (!node)
 539     {
 540       /* no node found, create a new one */
 541       node = nobug_resource_node_new (resource, user?user->current:NULL);
 542       if (!node)
 543         {
 544           nobug_resource_error = "internal allocation error";
 545           return NULL;
 546         }
 547     }
 548
 549   new_user->current = node;
 550   new_user->thread = tls;
 551   llist_insert_tail (&tls->res_stack, llist_init (&new_user->res_stack));
 552 #endif
 553
 554   NOBUG_RESOURCE_UNLOCK;
 555   return new_user;
 556 }
 557
 558
 559 #if NOBUG_USE_PTHREAD
 560 static int
 561 nobug_resource_node_parent_cmpfn (const_LList a, const_LList b, void* extra)
 562 {
 563   (void) extra;
 564   return ((struct nobug_resource_node*)a)->parent ==
 565     ((struct nobug_resource_node*)b)->parent?0:-1;
 566 }
 567 #endif
 568
 569
 570 int
 571 nobug_resource_leave (struct nobug_resource_user* user)
 572 {
 573   NOBUG_RESOURCE_LOCK;
 574
 575   if (!user)
 576     {
 577       nobug_resource_error = "no handle";
 578       return 0;
 579     }
 580
 581
 582   if (!user->current?user->current->resource:NULL)
 583     {
 584       nobug_resource_error = "not entered";
 585       return 0;
 586     }
 587   else
 588     {
 589       //dlalgo
 590       //dlalgo HEAD^ Leaving Resources; nobug_resource_leave; fix resource lists
 591       //dlalgo
 592       //dlalgo store the tail and next aside, we need it later
 593       //dlalgo
 594       //dlalgo [source,c]
 595       //dlalgo ---------------------------------------------------------------------
 596 #if NOBUG_USE_PTHREAD                                                           //dlalgo VERBATIM
 597       struct nobug_resource_user* tail =                                        //dlalgo VERBATIM
 598         LLIST_TO_STRUCTP (llist_tail (&user->thread->res_stack),                //dlalgo VERBATIM
 599                           struct nobug_resource_user,                           //dlalgo VERBATIM
 600                           res_stack);                                           //dlalgo VERBATIM
 601
 602       struct nobug_resource_user* next =                                        //dlalgo VERBATIM
 603         LLIST_TO_STRUCTP (llist_next (&user->res_stack),                        //dlalgo VERBATIM
 604                           struct nobug_resource_user,                           //dlalgo VERBATIM
 605                           res_stack);                                           //dlalgo VERBATIM
 606       //dlalgo ---------------------------------------------------------------------
 607       //dlalgo
 608       //dlalgo remove user struct from thread stack
 609       //dlalgo The res_stack is now like it is supposed to look like with the 'user' removed.
 610       //dlalgo We now need to fix the node tree up to match this list.
 611       //dlalgo
 612       //dlalgo [source,c]
 613       //dlalgo ---------------------------------------------------------------------
 614       llist_unlink_fast_ (&user->res_stack);                                    //dlalgo VERBATIM
 615       //dlalgo ---------------------------------------------------------------------
 616       //dlalgo
 617       //dlalgo When the the user node was not the tail or only node of the thread stack, we have to check
 618       //dlalgo (and possibly construct) a new node chain for it. No valdation of this chain needs to be done,
 619       //dlalgo since it was already validated when entering the resources first.
 620       //dlalgo
 621       //dlalgo [source,c]
 622       //dlalgo ---------------------------------------------------------------------
 623       if (user != tail && !llist_is_empty (&user->thread->res_stack))           //dlalgo VERBATIM
 624         {                                                                       //dlalgo VERBATIM
 625           struct nobug_resource_user* parent = NULL;                            //dlalgo VERBATIM
 626           if (llist_head (&user->thread->res_stack) != &next->res_stack)        //dlalgo VERBATIM
 627             {                                                                   //dlalgo VERBATIM
 628               parent =                                                          //dlalgo VERBATIM
 629                 LLIST_TO_STRUCTP (llist_prev (&next->res_stack),                //dlalgo VERBATIM
 630                                   struct nobug_resource_user,                   //dlalgo VERBATIM
 631                                   res_stack);                                   //dlalgo VERBATIM
 632             }                                                                   //dlalgo VERBATIM
 633           //dlalgo ---------------------------------------------------------------------
 634           //dlalgo
 635           //dlalgo iterate over all users following the removed node, finding nodes pointing to this users or
 636           //dlalgo create new nodes.
 637           //dlalgo
 638           //dlalgo [source,c]
 639           //dlalgo ---------------------------------------------------------------------
 640           LLIST_FORRANGE (&next->res_stack, &user->thread->res_stack, n)        //dlalgo VERBATIM
 641             {                                                                   //dlalgo VERBATIM
 642               struct nobug_resource_user* cur =                                 //dlalgo VERBATIM
 643                 LLIST_TO_STRUCTP (n,                                            //dlalgo VERBATIM
 644                                   struct nobug_resource_user,                   //dlalgo VERBATIM
 645                                   res_stack);                                   //dlalgo VERBATIM
 646               //dlalgo VERBATIM
 647               struct nobug_resource_record* resource = cur->current->resource;
 648
 649               //dlalgo ---------------------------------------------------------------------
 650               //TODO this search could be optimized out after we creates a node once,
 651               //TODO    all following nodes need to be created too
 652               //dlalgo
 653               //dlalgo find the node pointing back to parent, create a new one if not found, rinse repeat
 654               //dlalgo
 655               //dlalgo [source,c]
 656               //dlalgo ---------------------------------------------------------------------
 657               struct nobug_resource_node templ =                                //dlalgo VERBATIM
 658                 {                                                               //dlalgo VERBATIM
 659                   {NULL, NULL},                                                 //dlalgo                   ...
 660                   NULL,                                                         //dlalgo VERBATIM
 661                   parent?parent->current:NULL,                                  //dlalgo                   ...
 662                   {NULL, NULL},
 663                   {NULL, NULL}
 664                 };                                                              //dlalgo VERBATIM
 665               //dlalgo VERBATIM
 666               struct nobug_resource_node* node = (struct nobug_resource_node*)  //dlalgo VERBATIM
 667                 llist_ufind (&resource->nodes,                                  //dlalgo VERBATIM
 668                              &templ.node,                                       //dlalgo VERBATIM
 669                              nobug_resource_node_parent_cmpfn,                  //dlalgo VERBATIM
 670                              NULL);                                             //dlalgo VERBATIM
 671               //dlalgo VERBATIM
 672               if (!node)                                                        //dlalgo VERBATIM
 673                 {                                                               //dlalgo VERBATIM
 674                   node = nobug_resource_node_new (resource,                     //dlalgo VERBATIM
 675                                                   parent?parent->current:NULL); //dlalgo VERBATIM
 676                   if (!node)                                                    //dlalgo VERBATIM
 677                     {                                                           //dlalgo VERBATIM
 678                       nobug_resource_error = "internal allocation error";       //dlalgo VERBATIM
 679                       return 0;                                                 //dlalgo VERBATIM
 680                     }                                                           //dlalgo VERBATIM
 681                 }                                                               //dlalgo VERBATIM
 682               //dlalgo VERBATIM
 683               parent = cur;                                                     //dlalgo VERBATIM
 684             }                                                                   //dlalgo VERBATIM
 685         }                                                                       //dlalgo VERBATIM
 686       //dlalgo ---------------------------------------------------------------------
 687       //dlalgo
 688 #endif
 689
 690       llist_unlink_fast_ (&user->hdr.node);
 691       mpool_free (&nobug_resource_user_pool, user);
 692     }
 693
 694   NOBUG_RESOURCE_UNLOCK;
 695   return 1;
 696 }
 697
 698
 699 int
 700 nobug_resource_state (struct nobug_resource_user* user,
 701                       enum nobug_resource_state state)
 702 {
 703   NOBUG_RESOURCE_LOCK;
 704   if (!user)
 705     {
 706       nobug_resource_error = "no user handle";
 707       return 0;
 708     }
 709
 710   if (user->state == NOBUG_RESOURCE_WAITING)
 711     {
 712       if (state == NOBUG_RESOURCE_EXCLUSIVE)
 713         {
 714           /* check that every one is waiting */
 715           LLIST_FOREACH (&user->current->resource->users, n)
 716             if (((struct nobug_resource_user*)n)->state != NOBUG_RESOURCE_WAITING)
 717               {
 718                 nobug_resource_error = "resource hold by another thread";
 719                 break;
 720               }
 721         }
 722 #if NOBUG_USE_PTHREAD
 723       else if (state == NOBUG_RESOURCE_RECURSIVE)
 724         {
 725           /* check that every one else is waiting */
 726           LLIST_FOREACH (&user->current->resource->users, n)
 727             if (((struct nobug_resource_user*)n)->state != NOBUG_RESOURCE_WAITING &&
 728                 ((struct nobug_resource_user*)n)->thread != nobug_thread_get ())
 729               {
 730                 nobug_resource_error = "resource hold by another thread";
 731                 break;
 732               }
 733         }
 734 #endif
 735       else if (state == NOBUG_RESOURCE_SHARED)
 736         {
 737           /* check that every one else is waiting or shared */
 738           LLIST_FOREACH (&user->current->resource->users, n)
 739             if (((struct nobug_resource_user*)n)->state != NOBUG_RESOURCE_WAITING
 740                 && ((struct nobug_resource_user*)n)->state != NOBUG_RESOURCE_SHARED)
 741               {
 742                 nobug_resource_error = "resource hold by another thread nonshared";
 743                 break;
 744               }
 745         }
 746       else
 747         nobug_resource_error = "invalid state transistion";
 748
 749       /* ok we got it */
 750       if (!nobug_resource_error)
 751         user->state = state;
 752     }
 753   else if (state == NOBUG_RESOURCE_WAITING)
 754     user->state = state;
 755   else
 756     nobug_resource_error = "invalid state transistion";
 757
 758   if (nobug_resource_error)
 759     return 0;
 760
 761   NOBUG_RESOURCE_UNLOCK;
 762   return 1;
 763 }
 764
 765
 766 void
 767 nobug_resource_dump (struct nobug_resource_record* resource, struct nobug_resource_dump_context* context)
 768 {
 769   if (!resource) return;
 770
 771 #if NOBUG_USE_PTHREAD
 772   nobug_log (context->flag, context->level,
 773              "%.10llu: RESOURCE_DUMP: %s:%d: %s: %s: "
 774              "%s %s:%s: hold by %u entities:",
 775              ++nobug_counter, context->file, context->line, nobug_thread_id_get(), context->func,
 776              resource->hdr.extra, resource->type, resource->hdr.name,
 777              llist_count (&resource->users));
 778 #else
 779   nobug_log (context->flag, context->level,
 780              "%.10llu: RESOURCE_DUMP: %s:%d: %s: "
 781              "%s %s:%s: hold by %u entities:",
 782              ++nobug_counter, context->file, context->line, context->func,
 783              resource->hdr.extra, resource->type, resource->hdr.name,
 784              llist_count (&resource->users));
 785 #endif
 786
 787   LLIST_FOREACH (&resource->users, n)
 788     {
 789       struct nobug_resource_user* node = (struct nobug_resource_user*)n;
 790 #if NOBUG_USE_PTHREAD
 791       nobug_log (context->flag, context->level,
 792                  "%.10llu: RESOURCE_DUMP:"NOBUG_TAB
 793                  "%s %s %s: %s",
 794                  ++nobug_counter,
 795                  node->hdr.extra, node->hdr.name, node->thread->thread_id,
 796                  nobug_resource_states[node->state]);
 797 #else
 798       nobug_log (context->flag, context->level,
 799                  "%.10llu: RESOURCE_DUMP: "NOBUG_TAB
 800                  "%s %s: %s",
 801                  ++nobug_counter,
 802                  node->hdr.extra, node->hdr.name, nobug_resource_states[node->state]);
 803 #endif
 804     }
 805 }
 806
 807
 808 void
 809 nobug_resource_dump_all (struct nobug_resource_dump_context* context)
 810 {
 811   LLIST_FOREACH (&nobug_resource_registry, n)
 812     {
 813       struct nobug_resource_record* node = (struct nobug_resource_record*)n;
 814       nobug_resource_dump (node, context);
 815     }
 816 }
 817
 818
 819 void
 820 nobug_resource_list (struct nobug_resource_dump_context* context)
 821 {
 822 #if NOBUG_USE_PTHREAD
 823           nobug_log (context->flag, context->level,
 824                      "%.10llu: RESOURCE_LIST: %s:%d: %s: %s:",
 825                      ++nobug_counter, context->file, context->line, nobug_thread_id_get(), context->func);
 826 #else
 827           nobug_log (context->flag, context->level,
 828                      "%.10llu: RESOURCE_LIST: %s:%d: %s:",
 829                      ++nobug_counter, context->file, context->line, context->func);
 830 #endif
 831
 832   if (!llist_is_empty (&nobug_resource_registry))
 833     {
 834       LLIST_FOREACH (&nobug_resource_registry, n)
 835         {
 836           struct nobug_resource_record* node = (struct nobug_resource_record*)n;
 837           nobug_log (context->flag, context->level,
 838                      "%.10llu: RESOURCE_LIST:"NOBUG_TAB
 839                      "%s %s: %s: %p",
 840                      ++nobug_counter,
 841                      node->hdr.extra, node->type, node->hdr.name, node->object_id);
 842         }
 843     }
 844   else
 845     {
 846       nobug_log (context->flag, context->level,
 847                  "%.10llu: RESOURCE_LIST:"NOBUG_TAB"No resources registered", ++nobug_counter);
 848     }
 849 }
 850
 851 /*
 852 //      Local Variables:
 853 //      mode: C
 854 //      c-file-style: "gnu"
 855 //      indent-tabs-mode: nil
 856 //      End:
 857 */