src/nobug_resources.c

   1 /*
   2  This file is part of the NoBug debugging library.
   3
   4  Copyright (C)
   5    2007, 2008, 2009, 2010,              Christian Thaeter <ct@pipapo.org>
   6
   7  This program is free software; you can redistribute it and/or modify
   8  it under the terms of the GNU General Public License as published by
   9  the Free Software Foundation; either version 2 of the License, or
  10  (at your option) any later version.
  11
  12  This program is distributed in the hope that it will be useful,
  13  but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  GNU General Public License for more details.
  16
  17  You should have received a copy of the GNU General Public License
  18  along with this program; if not, contact Christian Thaeter <ct@pipapo.org>.
  19 */
  20 #include <stdlib.h>
  21
  22 #define NOBUG_LIBNOBUG_C
  23 #include "nobug.h"
  24 #include "llist.h"
  25 #include "mpool.h"
  26
  27 /*
  28 //deadlock There are 2 kinds of nodes: `resource_record` hold registered resources and `resource_user` which
  29 //deadlock attach to (enter) a resource.
  30 //deadlock
  31 //deadlock Each thread keeps stacklist of each `resource_user` it created, new enters will push on the stack,
  32 //deadlock leaving a resource will remove it from this stacklist.
  33 //deadlock
  34 //deadlock All `resource_records` in use are linked in a global precedence list, items of equal precedence are
  35 //deadlock spaned by a skip pointer. Whenever a resource is entered the deadlock checker asserts that one does
  36 //deadlock not break existing precedences. By doing so the precedence list gets continously refined as the system
  37 //deadlock learns about new lock patterns.
  38 //deadlock
  39 //deadlock As a consequence of this algorithm the deadlock checker does not only find real deadlocks but
  40 //deadlock already potential deadlocks by violations of the locking order which is a lot simpler than finding
  41 //deadlock actual deadlocks.
  42 //deadlock
  43 //deadlock This also means that the deadlock tracker currently only works with hierarchical locking policies
  44 //deadlock other approaches to prevent deadlocks are not yet supported and will be added on demand.
  45 //deadlock
  46 //deadlock
  47 //deadlock
  48 */
  49
  50 /*
  51   How much memory to reserve for a mpool chunk, 16k by default
  52  */
  53 #ifndef NOBUG_RESOURCE_MPOOL_CHUNKSIZE
  54 #define NOBUG_RESOURCE_MPOOL_CHUNKSIZE (4096<<(sizeof(void*)/4))        /* That is roughly 8k chunks on 32bit, 16k chunks on 64 bit machines */
  55 #endif
  56
  57 #if NOBUG_USE_PTHREAD
  58 pthread_mutex_t nobug_resource_mutex;
  59 #endif
  60
  61 #define nobug_resourcestates    \
  62   resource_state(invalid),      \
  63   resource_state(waiting),      \
  64   resource_state(trying),       \
  65   resource_state(exclusive),    \
  66   resource_state(recursive),    \
  67   resource_state(shared),
  68
  69
  70 #define resource_state(name) #name
  71 const char* nobug_resource_states[] =
  72   {
  73     nobug_resourcestates
  74     NULL
  75   };
  76 #undef resource_state
  77
  78 const char* nobug_resource_error = NULL;
  79
  80 static llist nobug_resource_registry;
  81 static nobug_mpool nobug_resource_record_pool;
  82 static nobug_mpool nobug_resource_user_pool;
  83 #if NOBUG_USE_PTHREAD
  84 static nobug_mpool nobug_resource_node_pool;
  85 #endif
  86
  87 static void nobug_resource_record_dtor (void*);
  88 static void nobug_resource_user_dtor (void*);
  89 #if NOBUG_USE_PTHREAD
  90 static void nobug_resource_node_dtor (void*);
  91 #endif
  92
  93
  94 void
  95 nobug_resource_init (void)
  96 {
  97 #if NOBUG_USE_PTHREAD
  98   static pthread_mutexattr_t attr;
  99   pthread_mutexattr_init (&attr);
 100   pthread_mutexattr_settype (&attr, PTHREAD_MUTEX_RECURSIVE);
 101   pthread_mutex_init (&nobug_resource_mutex, &attr);
 102 #endif
 103
 104   llist_init (&nobug_resource_registry);
 105
 106   nobug_mpool_init (&nobug_resource_record_pool,
 107               sizeof(struct nobug_resource_record),
 108               NOBUG_RESOURCE_MPOOL_CHUNKSIZE/sizeof(struct nobug_resource_record),
 109               nobug_resource_record_dtor);
 110
 111   nobug_mpool_init (&nobug_resource_user_pool,
 112               sizeof(struct nobug_resource_user),
 113               NOBUG_RESOURCE_MPOOL_CHUNKSIZE/sizeof(struct nobug_resource_user),
 114               nobug_resource_user_dtor);
 115
 116 #if NOBUG_USE_PTHREAD
 117   nobug_mpool_init (&nobug_resource_node_pool,
 118               sizeof(struct nobug_resource_node),
 119               NOBUG_RESOURCE_MPOOL_CHUNKSIZE/sizeof(struct nobug_resource_node),
 120               nobug_resource_node_dtor);
 121 #endif
 122 }
 123
 124
 125 void
 126 nobug_resource_destroy (void)
 127 {
 128 #if NOBUG_USE_PTHREAD
 129   nobug_mpool_destroy (&nobug_resource_node_pool);
 130 #endif
 131   nobug_mpool_destroy (&nobug_resource_user_pool);
 132   nobug_mpool_destroy (&nobug_resource_record_pool);
 133 }
 134
 135
 136 unsigned
 137 nobug_resource_record_available (void)
 138 {
 139   return nobug_mpool_available (&nobug_resource_record_pool);
 140 }
 141
 142
 143 unsigned
 144 nobug_resource_user_available (void)
 145 {
 146   return nobug_mpool_available (&nobug_resource_user_pool);
 147 }
 148
 149
 150 #if NOBUG_USE_PTHREAD
 151 unsigned
 152 nobug_resource_node_available (void)
 153 {
 154   return nobug_mpool_available (&nobug_resource_node_pool);
 155 }
 156
 157
 158 static void
 159 nobug_resource_node_free (struct nobug_resource_node* self)
 160 {
 161   LLIST_WHILE_HEAD (&self->childs, c)
 162     nobug_resource_node_free (LLIST_TO_STRUCTP(c, struct nobug_resource_node, cldnode));
 163
 164   llist_unlink_fast_ (&self->cldnode);
 165   llist_unlink_fast_ (&self->node);
 166   nobug_mpool_free (&nobug_resource_node_pool, self);
 167 }
 168
 169
 170 static void
 171 nobug_resource_node_dtor (void* p)
 172 {
 173   struct nobug_resource_node* n = p;
 174   llist_unlink_fast_ (&n->node);
 175   /* must unlink childs, because we don't destroy the tree bottom up */
 176   llist_unlink_fast_ (&n->childs);
 177   llist_unlink_fast_ (&n->cldnode);
 178 }
 179 #endif
 180
 181
 182 static void
 183 nobug_resource_record_dtor (void* p)
 184 {
 185   struct nobug_resource_record* self = p;
 186   llist_unlink_fast_ (&self->hdr.node);
 187
 188 #if NOBUG_USE_PTHREAD
 189   /* destroy all nodes recursively */
 190   LLIST_WHILE_HEAD (&self->nodes, n)
 191     nobug_resource_node_free ((struct nobug_resource_node*)n);
 192 #endif
 193 }
 194
 195
 196 static void
 197 nobug_resource_user_dtor (void* p)
 198 {
 199   struct nobug_resource_user* u = p;
 200   llist_unlink_fast_ (&u->hdr.node);
 201 #if NOBUG_USE_PTHREAD
 202   llist_unlink_fast_ (&u->res_stack);
 203 #endif
 204 }
 205
 206
 207 static int
 208 compare_resource_records (const_LList av, const_LList bv, void* unused)
 209 {
 210   (void) unused;
 211   const struct nobug_resource_record* a = (const struct nobug_resource_record*)av;
 212   const struct nobug_resource_record* b = (const struct nobug_resource_record*)bv;
 213
 214   return a->object_id > b->object_id ? 1 : a->object_id < b->object_id ? -1 : 0;
 215 }
 216
 217
 218 struct nobug_resource_record*
 219 nobug_resource_announce (const char* type, const char* name, const void* object_id, const struct nobug_context extra)
 220 {
 221 #if NOBUG_USE_PTHREAD
 222   pthread_mutex_lock (&nobug_resource_mutex);
 223 #endif
 224
 225   struct nobug_resource_record* node = nobug_mpool_alloc (&nobug_resource_record_pool);
 226   if (!node)
 227     {
 228       nobug_resource_error = "internal allocation error";
 229       return NULL;
 230     }
 231
 232   node->hdr.name = name;
 233   node->object_id = object_id;
 234   node->type = type;
 235
 236   /* TODO better lookup method than list search (psplay?) */
 237   if (llist_ufind (&nobug_resource_registry, &node->hdr.node, compare_resource_records, NULL))
 238     {
 239       nobug_resource_error = "already registered";
 240       return NULL;
 241     }
 242
 243   llist_init (&node->users);
 244   node->hdr.extra = extra;
 245 #if NOBUG_USE_PTHREAD
 246   llist_init (&node->nodes);
 247 #endif
 248
 249   llist_insert_head (&nobug_resource_registry, llist_init (&node->hdr.node));
 250
 251   return node;
 252 }
 253
 254 void
 255 nobug_resource_announce_complete (void)
 256 {
 257 #if NOBUG_USE_PTHREAD
 258   pthread_mutex_unlock (&nobug_resource_mutex);
 259 #endif
 260 }
 261
 262
 263 int
 264 nobug_resource_forget (struct nobug_resource_record* self)
 265 {
 266 #if NOBUG_USE_PTHREAD
 267   pthread_mutex_lock (&nobug_resource_mutex);
 268 #endif
 269   if (!llist_find (&nobug_resource_registry, &self->hdr.node, compare_resource_records, NULL))
 270     {
 271       nobug_resource_error = "not registered";
 272       return 0;
 273     }
 274
 275   if (!llist_is_empty (&self->users))
 276     {
 277       nobug_resource_error = "still in use";
 278       return 0;
 279     }
 280
 281   nobug_resource_record_dtor (self);
 282
 283   nobug_mpool_free (&nobug_resource_record_pool, self);
 284
 285 #if NOBUG_USE_PTHREAD
 286   pthread_mutex_unlock (&nobug_resource_mutex);
 287 #endif
 288
 289   return 1;
 290 }
 291
 292
 293
 294 #if NOBUG_USE_PTHREAD
 295 static int
 296 nobug_resource_node_resource_cmpfn (const_LList a, const_LList b, void* extra)
 297 {
 298   (void) extra;
 299   return ((struct nobug_resource_node*)a)->resource ==
 300     ((struct nobug_resource_node*)b)->resource?0:-1;
 301 }
 302
 303
 304 struct nobug_resource_node*
 305 nobug_resource_node_new (struct nobug_resource_record* resource,
 306                          struct nobug_resource_node* parent)
 307 {
 308   struct nobug_resource_node* self = nobug_mpool_alloc (&nobug_resource_node_pool);
 309   if (self)
 310     {
 311       llist_insert_head (&resource->nodes, llist_init (&self->node));
 312       self->resource = resource;
 313
 314       self->parent = parent;
 315
 316       llist_init (&self->childs);
 317       llist_init (&self->cldnode);
 318       if (parent)
 319         llist_insert_head (&parent->childs, &self->cldnode);
 320     }
 321   return self;
 322 }
 323 #endif
 324
 325
 326 //dlalgo HEAD~ The Resource Tracking Algorithm; deadlock_detection; how resources are tracked
 327 //dlalgo
 328 //dlalgo Each resource registers a global 'resource_record'.
 329 //dlalgo
 330 //dlalgo Every new locking path discovered is stored as 'resource_node' structures which refer to the associated
 331 //dlalgo 'resource_record'.
 332 //dlalgo
 333 //dlalgo Threads keep a trail of 'resource_user' strcutures for each resource entered. This 'resource_user' struct
 334 //dlalgo refer to the 'resource_nodes' and thus indirectly to the associated 'resource_record'.
 335 //dlalgo
 336 //dlalgo The deadlock checker uses this information to test if the acqusition of a new resource would yield a
 337 //dlalgo potential deadlock.
 338 //dlalgo
 339 struct nobug_resource_user*
 340 nobug_resource_enter (struct nobug_resource_record* resource,
 341                       const char* identifier,
 342                       enum nobug_resource_state state,
 343                       const struct nobug_context extra)
 344 {
 345   if (!resource)
 346     {
 347       nobug_resource_error = "no resource";
 348       return NULL;
 349     }
 350
 351 #if NOBUG_USE_PTHREAD
 352   pthread_mutex_lock (&nobug_resource_mutex);
 353
 354   struct nobug_tls_data* tls = nobug_thread_get ();
 355
 356   //dlalgo HEAD^ Entering Resources; nobug_resource_enter; deadlock check on enter
 357   //dlalgo
 358   //dlalgo In multithreaded programs, whenever a thread wants to wait for a 'resource_record'
 359   //dlalgo the deadlock checker jumps in.
 360   //dlalgo
 361   //dlalgo The deadlock checking algorithm is anticipatory as it will find and abort on conditions which may lead
 362   //dlalgo to a potential deadlock by violating the locking order learned earlier.
 363   //dlalgo
 364   //dlalgo Each thread holds a stack (list) of each 'resource_user' it created. Leaving
 365   //dlalgo a resource will remove it from this stacklist.
 366   //dlalgo
 367   //dlalgo Each 'resource_record' stores the trail which other 'resource_records' are already entered. This relations
 368   //dlalgo are implemented with the 'resource_node' helper structure.
 369   //dlalgo
 370   //dlalgo ////
 371   //dlalgo TODO: insert diagram here
 372   //dlalgo   2-3
 373   //dlalgo 1
 374   //dlalgo   3-4-2
 375   //dlalgo
 376   //dlalgo 1-3-2-4
 377   //dlalgo
 378   //dlalgo 3-4-2
 379   //dlalgo
 380   //dlalgo 1-4-2
 381   //dlalgo
 382   //dlalgo ////
 383   //dlalgo
 384   //dlalgo First we find out if there is already a node from the to be acquired resource back to
 385   //dlalgo the topmost node of the current threads user stack.
 386   //dlalgo
 387   //dlalgo [source,c]
 388   //dlalgo ---------------------------------------------------------------------
 389   struct nobug_resource_user* user = NULL;                      //dlalgo VERBATIM
 390   struct nobug_resource_node* node = NULL;                      //dlalgo VERBATIM
 391                                                                 //dlalgo VERBATIM
 392   if (!llist_is_empty (&tls->res_stack))                        //dlalgo VERBATIM
 393     {                                                           //dlalgo VERBATIM
 394       user = LLIST_TO_STRUCTP (llist_tail (&tls->res_stack),    //dlalgo VERBATIM
 395                                struct nobug_resource_user,      //dlalgo VERBATIM
 396                                res_stack);                      //dlalgo VERBATIM
 397                                                                 //dlalgo VERBATIM
 398       struct nobug_resource_node templ =                        //dlalgo VERBATIM
 399         {                                                       //dlalgo VERBATIM
 400           {NULL, NULL},                                         //dlalgo          ...
 401           user->current->resource,                              //dlalgo VERBATIM
 402           NULL,                                                 //dlalgo          ...
 403           {NULL, NULL},
 404           {NULL, NULL}
 405         };                                                      //dlalgo VERBATIM
 406                                                                 //dlalgo VERBATIM
 407       node = (struct nobug_resource_node*)                      //dlalgo VERBATIM
 408         llist_ufind (&resource->nodes,                          //dlalgo VERBATIM
 409                      &templ.node,                               //dlalgo VERBATIM
 410                      nobug_resource_node_resource_cmpfn,        //dlalgo VERBATIM
 411                      NULL);                                     //dlalgo VERBATIM
 412     }                                                           //dlalgo VERBATIM
 413   //dlalgo   ...
 414   //dlalgo ---------------------------------------------------------------------
 415   //dlalgo
 416 #endif
 417
 418   //dlalgo Deadlock checking is only done when the node is entered in `WAITING` state and only
 419   //dlalgo available in multithreaded programs.
 420   //dlalgo
 421   //dlalgo [source,c]
 422   //dlalgo ---------------------------------------------------------------------
 423   if (state == NOBUG_RESOURCE_WAITING)                          //dlalgo VERBATIM
 424     {                                                           //dlalgo VERBATIM
 425 #if NOBUG_USE_PTHREAD                                           //dlalgo VERBATIM
 426       //dlalgo       ...
 427       //dlalgo ---------------------------------------------------------------------
 428       //dlalgo
 429
 430       //dlalgo If node was found above, then this locking path is already validated and no deadlock can happen,
 431       //dlalgo else, if this stack already holds a resource (user is set) we have to go on with checking.
 432       //dlalgo
 433       //dlalgo [source,c]
 434       //dlalgo ---------------------------------------------------------------------
 435       if (!node && user)                                                //dlalgo VERBATIM
 436         {                                                               //dlalgo VERBATIM
 437           //dlalgo           ...
 438           //dlalgo ---------------------------------------------------------------------
 439           //dlalgo
 440           //dlalgo If not then its checked that the resource to be entered is not on any parent trail of the current topmost resource,
 441           //dlalgo if it is then this could be a deadlock which needs to be further investigated.
 442           //dlalgo
 443           //dlalgo [source,c]
 444           //dlalgo ---------------------------------------------------------------------
 445           LLIST_FOREACH (&user->current->resource->nodes, n)            //dlalgo VERBATIM
 446             {                                                           //dlalgo VERBATIM
 447               for (struct nobug_resource_node* itr =                    //dlalgo VERBATIM
 448                      ((struct nobug_resource_node*)n)->parent;          //dlalgo VERBATIM
 449                    itr;                                                 //dlalgo VERBATIM
 450                    itr = itr->parent)                                   //dlalgo VERBATIM
 451                 {                                                       //dlalgo VERBATIM
 452                   if (itr->resource == resource)                        //dlalgo VERBATIM
 453                     {                                                   //dlalgo VERBATIM
 454                       //dlalgo                       ...
 455                       //dlalgo ---------------------------------------------------------------------
 456                       //dlalgo
 457                       //dlalgo if the resource was on the trail, we search if there is a common ancestor before the resource
 458                       //dlalgo on the trail and the threads current chain,
 459                       //dlalgo if yes then this ancestor protects against deadlocks and we can continue.
 460                       //dlalgo
 461                       //dlalgo [source,c]
 462                       //dlalgo ---------------------------------------------------------------------
 463                       for (struct nobug_resource_node* itr2 = itr->parent;              //dlalgo VERBATIM
 464                            itr2;                                                        //dlalgo VERBATIM
 465                            itr2 = itr2->parent)                                         //dlalgo VERBATIM
 466                         {                                                               //dlalgo VERBATIM
 467                           LLIST_FOREACH_REV (&tls->res_stack, p)                        //dlalgo VERBATIM
 468                             {                                                           //dlalgo VERBATIM
 469                               struct nobug_resource_user* user =                        //dlalgo VERBATIM
 470                                 LLIST_TO_STRUCTP (p,                                    //dlalgo VERBATIM
 471                                                   struct nobug_resource_user,           //dlalgo VERBATIM
 472                                                   res_stack);                           //dlalgo VERBATIM
 473                               if (user->current->resource == itr2->resource)            //dlalgo VERBATIM
 474                                 goto done;                                              //dlalgo VERBATIM
 475                             }                                                           //dlalgo VERBATIM
 476                           //dlalgo ---------------------------------------------------------------------
 477                           //dlalgo
 478                           //dlalgo If no ancestor found, we finally abort with a potential deadlock condition.
 479                           //dlalgo
 480                           //dlalgo [source,c]
 481                           //dlalgo ---------------------------------------------------------------------
 482                           nobug_resource_error = "possible deadlock detected";          //dlalgo VERBATIM
 483                           return NULL;                                                  //dlalgo VERBATIM
 484                           //dlalgo                           ...
 485                           //dlalgo ---------------------------------------------------------------------
 486                           //dlalgo
 487                         }
 488                     }
 489                 }
 490             }
 491         }
 492     done:;
 493 #endif
 494     }
 495   else if (state == NOBUG_RESOURCE_TRYING)
 496     {
 497       /* nothing */
 498     }
 499   else if (state == NOBUG_RESOURCE_EXCLUSIVE)
 500     {
 501       /* check that everyone is waiting */
 502       LLIST_FOREACH (&resource->users, n)
 503         if (((struct nobug_resource_user*)n)->state != NOBUG_RESOURCE_WAITING &&
 504             ((struct nobug_resource_user*)n)->state != NOBUG_RESOURCE_TRYING)
 505           {
 506             nobug_resource_error = "invalid enter state (resource already claimed)";
 507             break;
 508           }
 509     }
 510 #if NOBUG_USE_PTHREAD
 511   else if (state == NOBUG_RESOURCE_RECURSIVE)
 512     {
 513       /* check that everyone *else* is waiting */
 514       LLIST_FOREACH (&resource->users, n)
 515         {
 516           struct nobug_resource_user* user = (struct nobug_resource_user*)n;
 517           if (user->state != NOBUG_RESOURCE_WAITING &&
 518               user->state != NOBUG_RESOURCE_TRYING &&
 519               user->thread != tls)
 520             {
 521               nobug_resource_error = "invalid enter state (resource already claimed non recursive by another thread)";
 522               break;
 523             }
 524           else if (!(user->state == NOBUG_RESOURCE_WAITING ||
 525                      user->state == NOBUG_RESOURCE_TRYING ||
 526                      user->state == NOBUG_RESOURCE_RECURSIVE) &&
 527                    user->thread == tls)
 528             {
 529               nobug_resource_error = "invalid enter state (resource already claimed non recursive by this thread)";
 530               break;
 531             }
 532         }
 533     }
 534 #endif
 535   else if (state == NOBUG_RESOURCE_SHARED)
 536     {
 537       /* check that every one else is waiting or hold it shared */
 538       LLIST_FOREACH (&resource->users, n)
 539         if (((struct nobug_resource_user*)n)->state != NOBUG_RESOURCE_WAITING &&
 540             ((struct nobug_resource_user*)n)->state != NOBUG_RESOURCE_TRYING &&
 541             ((struct nobug_resource_user*)n)->state != NOBUG_RESOURCE_SHARED)
 542           {
 543             nobug_resource_error = "invalid enter state (resource already claimed non shared)";
 544             break;
 545           }
 546     }
 547   else
 548     nobug_resource_error = "invalid enter state";
 549
 550   if (nobug_resource_error)
 551     return NULL;
 552
 553   struct nobug_resource_user* new_user = nobug_mpool_alloc (&nobug_resource_user_pool);
 554   if (!new_user)
 555     {
 556       nobug_resource_error = "internal allocation error";
 557       return NULL;
 558     }
 559
 560   new_user->hdr.name = identifier;
 561   new_user->hdr.extra = extra;
 562   new_user->state = state;
 563   llist_insert_head (&resource->users, llist_init (&new_user->hdr.node));
 564
 565 #if NOBUG_USE_PTHREAD
 566   if (!node)
 567     {
 568       /* no node found, create a new one */
 569       node = nobug_resource_node_new (resource, user?user->current:NULL);
 570       if (!node)
 571         {
 572           nobug_resource_error = "internal allocation error";
 573           return NULL;
 574         }
 575     }
 576
 577   new_user->current = node;
 578   new_user->thread = tls;
 579   llist_insert_tail (&tls->res_stack, llist_init (&new_user->res_stack));
 580
 581   pthread_mutex_unlock (&nobug_resource_mutex);
 582 #endif
 583
 584   return new_user;
 585 }
 586
 587
 588 #if NOBUG_USE_PTHREAD
 589 static int
 590 nobug_resource_node_parent_cmpfn (const_LList a, const_LList b, void* extra)
 591 {
 592   (void) extra;
 593   return ((struct nobug_resource_node*)a)->parent ==
 594     ((struct nobug_resource_node*)b)->parent?0:-1;
 595 }
 596 #endif
 597
 598
 599 void
 600 nobug_resource_leave_pre (void)
 601 {
 602 #if NOBUG_USE_PTHREAD
 603   pthread_mutex_lock (&nobug_resource_mutex);
 604 #endif
 605 }
 606
 607
 608 int
 609 nobug_resource_leave (struct nobug_resource_user* user)
 610 {
 611   if (!user)
 612     {
 613       nobug_resource_error = "no handle";
 614       return 0;
 615     }
 616
 617   if (!user->current?user->current->resource:NULL)
 618     {
 619       nobug_resource_error = "not entered";
 620       return 0;
 621     }
 622   else
 623     {
 624       //dlalgo
 625       //dlalgo HEAD^ Leaving Resources; nobug_resource_leave; fix resource lists
 626       //dlalgo
 627       //dlalgo store the tail and next aside, we need it later
 628       //dlalgo
 629       //dlalgo [source,c]
 630       //dlalgo ---------------------------------------------------------------------
 631 #if NOBUG_USE_PTHREAD                                                           //dlalgo VERBATIM
 632       struct nobug_resource_user* tail =                                        //dlalgo VERBATIM
 633         LLIST_TO_STRUCTP (llist_tail (&user->thread->res_stack),                //dlalgo VERBATIM
 634                           struct nobug_resource_user,                           //dlalgo VERBATIM
 635                           res_stack);                                           //dlalgo VERBATIM
 636
 637       struct nobug_resource_user* next =                                        //dlalgo VERBATIM
 638         LLIST_TO_STRUCTP (llist_next (&user->res_stack),                        //dlalgo VERBATIM
 639                           struct nobug_resource_user,                           //dlalgo VERBATIM
 640                           res_stack);                                           //dlalgo VERBATIM
 641       //dlalgo ---------------------------------------------------------------------
 642       //dlalgo
 643       //dlalgo remove user struct from thread stack
 644       //dlalgo The res_stack is now like it is supposed to look like with the 'user' removed.
 645       //dlalgo We now need to fix the node tree up to match this list.
 646       //dlalgo
 647       //dlalgo [source,c]
 648       //dlalgo ---------------------------------------------------------------------
 649       llist_unlink_fast_ (&user->res_stack);                                    //dlalgo VERBATIM
 650       //dlalgo ---------------------------------------------------------------------
 651       //dlalgo
 652       //dlalgo When the the user node was not the tail or only node of the thread stack, we have to check
 653       //dlalgo (and possibly construct) a new node chain for it. No valdation of this chain needs to be done,
 654       //dlalgo since it was already validated when entering the resources first.
 655       //dlalgo
 656       //dlalgo [source,c]
 657       //dlalgo ---------------------------------------------------------------------
 658       if (user != tail && !llist_is_empty (&user->thread->res_stack))           //dlalgo VERBATIM
 659         {                                                                       //dlalgo VERBATIM
 660           struct nobug_resource_user* parent = NULL;                            //dlalgo VERBATIM
 661           if (llist_head (&user->thread->res_stack) != &next->res_stack)        //dlalgo VERBATIM
 662             {                                                                   //dlalgo VERBATIM
 663               parent =                                                          //dlalgo VERBATIM
 664                 LLIST_TO_STRUCTP (llist_prev (&next->res_stack),                //dlalgo VERBATIM
 665                                   struct nobug_resource_user,                   //dlalgo VERBATIM
 666                                   res_stack);                                   //dlalgo VERBATIM
 667             }                                                                   //dlalgo VERBATIM
 668           //dlalgo ---------------------------------------------------------------------
 669           //dlalgo
 670           //dlalgo iterate over all users following the removed node, finding nodes pointing to this users or
 671           //dlalgo create new nodes.
 672           //dlalgo
 673           //dlalgo [source,c]
 674           //dlalgo ---------------------------------------------------------------------
 675           LLIST_FORRANGE (&next->res_stack, &user->thread->res_stack, n)        //dlalgo VERBATIM
 676             {                                                                   //dlalgo VERBATIM
 677               struct nobug_resource_user* cur =                                 //dlalgo VERBATIM
 678                 LLIST_TO_STRUCTP (n,                                            //dlalgo VERBATIM
 679                                   struct nobug_resource_user,                   //dlalgo VERBATIM
 680                                   res_stack);                                   //dlalgo VERBATIM
 681               //dlalgo VERBATIM
 682               struct nobug_resource_record* resource = cur->current->resource;
 683
 684               //dlalgo ---------------------------------------------------------------------
 685               //TODO this search could be optimized out after we creates a node once,
 686               //TODO    all following nodes need to be created too
 687               //dlalgo
 688               //dlalgo find the node pointing back to parent, create a new one if not found, rinse repeat
 689               //dlalgo
 690               //dlalgo [source,c]
 691               //dlalgo ---------------------------------------------------------------------
 692               struct nobug_resource_node templ =                                //dlalgo VERBATIM
 693                 {                                                               //dlalgo VERBATIM
 694                   {NULL, NULL},                                                 //dlalgo                   ...
 695                   NULL,                                                         //dlalgo VERBATIM
 696                   parent?parent->current:NULL,                                  //dlalgo                   ...
 697                   {NULL, NULL},
 698                   {NULL, NULL}
 699                 };                                                              //dlalgo VERBATIM
 700               //dlalgo VERBATIM
 701               struct nobug_resource_node* node = (struct nobug_resource_node*)  //dlalgo VERBATIM
 702                 llist_ufind (&resource->nodes,                                  //dlalgo VERBATIM
 703                              &templ.node,                                       //dlalgo VERBATIM
 704                              nobug_resource_node_parent_cmpfn,                  //dlalgo VERBATIM
 705                              NULL);                                             //dlalgo VERBATIM
 706               //dlalgo VERBATIM
 707               if (!node)                                                        //dlalgo VERBATIM
 708                 {                                                               //dlalgo VERBATIM
 709                   node = nobug_resource_node_new (resource,                     //dlalgo VERBATIM
 710                                                   parent?parent->current:NULL); //dlalgo VERBATIM
 711                   if (!node)                                                    //dlalgo VERBATIM
 712                     {                                                           //dlalgo VERBATIM
 713                       nobug_resource_error = "internal allocation error";       //dlalgo VERBATIM
 714                       return 0;                                                 //dlalgo VERBATIM
 715                     }                                                           //dlalgo VERBATIM
 716                 }                                                               //dlalgo VERBATIM
 717               //dlalgo VERBATIM
 718               parent = cur;                                                     //dlalgo VERBATIM
 719             }                                                                   //dlalgo VERBATIM
 720         }                                                                       //dlalgo VERBATIM
 721       //dlalgo ---------------------------------------------------------------------
 722       //dlalgo
 723 #endif
 724
 725       llist_unlink_fast_ (&user->hdr.node);
 726       nobug_mpool_free (&nobug_resource_user_pool, user);
 727     }
 728
 729
 730 #if NOBUG_USE_PTHREAD
 731   pthread_mutex_unlock (&nobug_resource_mutex);
 732 #endif
 733
 734   return 1;
 735 }
 736
 737
 738 int
 739 nobug_resource_state (struct nobug_resource_user* user,
 740                       enum nobug_resource_state state)
 741 {
 742   if (!user)
 743     {
 744       nobug_resource_error = "no user handle";
 745       return 0;
 746     }
 747
 748 #if NOBUG_USE_PTHREAD
 749   pthread_mutex_lock (&nobug_resource_mutex);
 750 #endif
 751
 752   if (user->state == NOBUG_RESOURCE_WAITING || user->state == NOBUG_RESOURCE_TRYING)
 753     {
 754       if (state == NOBUG_RESOURCE_EXCLUSIVE)
 755         {
 756           /* check that every one is waiting */
 757           LLIST_FOREACH (&user->current->resource->users, n)
 758             if (((struct nobug_resource_user*)n)->state != NOBUG_RESOURCE_WAITING)
 759               {
 760                 nobug_resource_error = "resource hold by another thread";
 761                 break;
 762               }
 763         }
 764 #if NOBUG_USE_PTHREAD
 765       else if (state == NOBUG_RESOURCE_RECURSIVE)
 766         {
 767           /* check that every one else is waiting */
 768           LLIST_FOREACH (&user->current->resource->users, n)
 769             if (((struct nobug_resource_user*)n)->state != NOBUG_RESOURCE_WAITING &&
 770                 ((struct nobug_resource_user*)n)->thread != nobug_thread_get ())
 771               {
 772                 nobug_resource_error = "resource hold by another thread";
 773                 break;
 774               }
 775         }
 776 #endif
 777       else if (state == NOBUG_RESOURCE_SHARED)
 778         {
 779           /* check that every one else is waiting or shared */
 780           LLIST_FOREACH (&user->current->resource->users, n)
 781             if (((struct nobug_resource_user*)n)->state != NOBUG_RESOURCE_WAITING
 782                 && ((struct nobug_resource_user*)n)->state != NOBUG_RESOURCE_SHARED)
 783               {
 784                 nobug_resource_error = "resource hold by another thread nonshared";
 785                 break;
 786               }
 787         }
 788       else
 789         nobug_resource_error = "invalid state transistion";
 790
 791       /* ok we got it */
 792       if (!nobug_resource_error)
 793         user->state = state;
 794     }
 795   else if (state == NOBUG_RESOURCE_WAITING || state == NOBUG_RESOURCE_TRYING)
 796     user->state = state;
 797   else
 798     nobug_resource_error = "invalid state transistion";
 799
 800   if (nobug_resource_error)
 801     return 0;
 802
 803 #if NOBUG_USE_PTHREAD
 804   pthread_mutex_unlock (&nobug_resource_mutex);
 805 #endif
 806
 807   return 1;
 808 }
 809
 810
 811 enum nobug_resource_state
 812 nobug_resource_mystate (struct nobug_resource_record* res)
 813 {
 814   enum nobug_resource_state ret = NOBUG_RESOURCE_INVALID;
 815 #if NOBUG_USE_PTHREAD
 816   pthread_mutex_lock (&nobug_resource_mutex);
 817   struct nobug_tls_data* iam = nobug_thread_get ();
 818 #endif
 819
 820   LLIST_FOREACH_REV (&res->users, u)
 821     {
 822       struct nobug_resource_user* user = (struct nobug_resource_user*) u;
 823 #if NOBUG_USE_PTHREAD
 824       if (user->thread == iam)
 825         ret = user->state;
 826 #else
 827       ret = user->state;
 828 #endif
 829     }
 830
 831 #if NOBUG_USE_PTHREAD
 832   pthread_mutex_unlock (&nobug_resource_mutex);
 833 #endif
 834
 835   return ret;
 836 }
 837
 838
 839 static void
 840 nobug_resource_dump_ (char** start, char* header, struct nobug_resource_record* resource, const struct nobug_resource_dump_context context)
 841 {
 842 #if NOBUG_USE_PTHREAD
 843   nobug_log_line (start, header, context.flag, context.level,
 844                   " %s:%d: %s:%s: hold by %u entities:",
 845                   nobug_basename(resource->hdr.extra.file), resource->hdr.extra.line,
 846                   resource->type, resource->hdr.name,
 847                   llist_count (&resource->users));
 848 #else
 849   nobug_log_line (start, header, context.flag, context.level,
 850                   " %s:%d: %s:%s: hold by %u entities:",
 851                   nobug_basename(resource->hdr.extra.file), resource->hdr.extra.line,
 852                   resource->type, resource->hdr.name,
 853                   llist_count (&resource->users));
 854 #endif
 855
 856   LLIST_FOREACH (&resource->users, n)
 857     {
 858       struct nobug_resource_user* node = (struct nobug_resource_user*)n;
 859 #if NOBUG_USE_PTHREAD
 860       nobug_log_line (start, header, context.flag, context.level,
 861                       NOBUG_TAB"%s:%d: %s %s: %s",
 862                       nobug_basename(node->hdr.extra.file), node->hdr.extra.line,
 863                       node->hdr.name, node->thread->thread_id,
 864                       nobug_resource_states[node->state]);
 865 #else
 866       nobug_log_line (start, header, context.flag, context.level,
 867                       NOBUG_TAB"%s:%d: %s: %s",
 868                       nobug_basename(node->hdr.extra.file), node->hdr.extra.line,
 869                       node->hdr.name, nobug_resource_states[node->state]);
 870 #endif
 871     }
 872 }
 873
 874 void
 875 nobug_resource_dump (struct nobug_resource_record* resource, const struct nobug_resource_dump_context context)
 876 {
 877   if (!resource) return;
 878
 879 #if NOBUG_USE_PTHREAD
 880   pthread_mutex_lock (&nobug_resource_mutex);
 881 #endif
 882
 883   char header[NOBUG_MAX_LOG_HEADER_SIZE];
 884   char* start = nobug_log_begin (header, context.flag, "RESOURCE_DUMP", context.ctx);
 885
 886   nobug_resource_dump_ (&start, header, resource, context);
 887
 888   nobug_log_end (context.flag, context.level);
 889
 890 #if NOBUG_USE_PTHREAD
 891   pthread_mutex_unlock (&nobug_resource_mutex);
 892 #endif
 893 }
 894
 895
 896 void
 897 nobug_resource_dump_all (const struct nobug_resource_dump_context context)
 898 {
 899 #if NOBUG_USE_PTHREAD
 900   pthread_mutex_lock (&nobug_resource_mutex);
 901 #endif
 902
 903   char header[NOBUG_MAX_LOG_HEADER_SIZE];
 904   char* start = nobug_log_begin (header, context.flag, "RESOURCE_DUMP", context.ctx);
 905
 906   LLIST_FOREACH (&nobug_resource_registry, n)
 907     {
 908       struct nobug_resource_record* node = (struct nobug_resource_record*)n;
 909       nobug_resource_dump_ (&start, header, node, context);
 910     }
 911
 912   nobug_log_end (context.flag, context.level);
 913
 914 #if NOBUG_USE_PTHREAD
 915   pthread_mutex_unlock (&nobug_resource_mutex);
 916 #endif
 917
 918 }
 919
 920
 921 void
 922 nobug_resource_list (const struct nobug_resource_dump_context context)
 923 {
 924 #if NOBUG_USE_PTHREAD
 925   pthread_mutex_lock (&nobug_resource_mutex);
 926 #endif
 927
 928   char header[NOBUG_MAX_LOG_HEADER_SIZE];
 929   char* start = nobug_log_begin (header, context.flag, "RESOURCE_LIST", context.ctx);
 930
 931   if (!llist_is_empty (&nobug_resource_registry))
 932     {
 933       LLIST_FOREACH (&nobug_resource_registry, n)
 934         {
 935           struct nobug_resource_record* node = (struct nobug_resource_record*)n;
 936           nobug_log_line (&start, header,
 937                           context.flag, context.level,
 938                           " %s:%d: %s: %s: %p",
 939                           nobug_basename(node->hdr.extra.file), node->hdr.extra.line,
 940                           node->type, node->hdr.name, node->object_id);
 941         }
 942     }
 943   else
 944     {
 945       nobug_log_line (&start, header, context.flag, context.level, " No resources registered");
 946     }
 947
 948   nobug_log_end (context.flag, context.level);
 949
 950 #if NOBUG_USE_PTHREAD
 951   pthread_mutex_unlock (&nobug_resource_mutex);
 952 #endif
 953 }
 954
 955 /*
 956 //      Local Variables:
 957 //      mode: C
 958 //      c-file-style: "gnu"
 959 //      indent-tabs-mode: nil
 960 //      End:
 961 */