drd_semaphore.c revision c4b56747db5d3a6f850366f9e033cf77861dce41
1/* -*- mode: C; c-basic-offset: 3; -*- */ 2/* 3 This file is part of drd, a thread error detector. 4 5 Copyright (C) 2006-2009 Bart Van Assche <bart.vanassche@gmail.com>. 6 7 This program is free software; you can redistribute it and/or 8 modify it under the terms of the GNU General Public License as 9 published by the Free Software Foundation; either version 2 of the 10 License, or (at your option) any later version. 11 12 This program is distributed in the hope that it will be useful, but 13 WITHOUT ANY WARRANTY; without even the implied warranty of 14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 15 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, write to the Free Software 19 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 20 02111-1307, USA. 21 22 The GNU General Public License is contained in the file COPYING. 23*/ 24 25 26#include "drd_clientobj.h" 27#include "drd_error.h" 28#include "drd_semaphore.h" 29#include "drd_suppression.h" 30#include "pub_tool_errormgr.h" // VG_(maybe_record_error)() 31#include "pub_tool_libcassert.h" // tl_assert() 32#include "pub_tool_libcprint.h" // VG_(printf)() 33#include "pub_tool_machine.h" // VG_(get_IP)() 34#include "pub_tool_mallocfree.h" // VG_(malloc), VG_(free) 35#include "pub_tool_threadstate.h" // VG_(get_running_tid)() 36 37 38/* Local functions. */ 39 40static void semaphore_cleanup(struct semaphore_info* p); 41 42 43/* Local variables. */ 44 45static Bool s_trace_semaphore; 46static ULong s_semaphore_segment_creation_count; 47 48 49/* Function definitions. */ 50 51/** Push a segment at the end of the queue 'p->last_sem_post_seg'. */ 52static void drd_segment_push(struct semaphore_info* p, Segment* sg) 53{ 54 Word n; 55 56 tl_assert(sg); 57 n = VG_(addToXA)(p->last_sem_post_seg, &sg); 58#if 0 59 VG_(message)(Vg_UserMsg, "0x%lx push: added at position %ld/%ld", 60 p->a1, n, VG_(sizeXA)(p->last_sem_post_seg)); 61#endif 62 tl_assert(*(Segment**)VG_(indexXA)(p->last_sem_post_seg, n) == sg); 63} 64 65/** Pop a segment from the beginning of the queue 'p->last_sem_post_seg'. */ 66static Segment* drd_segment_pop(struct semaphore_info* p) 67{ 68 Word sz; 69 Segment* sg; 70 71 sz = VG_(sizeXA)(p->last_sem_post_seg); 72#if 0 73 VG_(message)(Vg_UserMsg, "0x%lx pop: removed from position %ld/%ld", 74 p->a1, sz - 1, sz); 75#endif 76 sg = 0; 77 if (sz > 0) 78 { 79 sg = *(Segment**)VG_(indexXA)(p->last_sem_post_seg, sz - 1); 80 tl_assert(sg); 81 VG_(dropTailXA)(p->last_sem_post_seg, 1); 82 } 83 return sg; 84} 85 86/** Enable or disable tracing of semaphore actions. */ 87void DRD_(semaphore_set_trace)(const Bool trace_semaphore) 88{ 89 s_trace_semaphore = trace_semaphore; 90} 91 92/** 93 * Initialize the memory 'p' points at as a semaphore_info structure for the 94 * client semaphore at client addres 'semaphore'. 95 */ 96static 97void drd_semaphore_initialize(struct semaphore_info* const p, 98 const Addr semaphore) 99{ 100 tl_assert(semaphore != 0); 101 tl_assert(p->a1 == semaphore); 102 tl_assert(p->type == ClientSemaphore); 103 104 p->cleanup = (void(*)(DrdClientobj*))semaphore_cleanup; 105 p->delete_thread = 0; 106 p->waits_to_skip = 0; 107 p->value = 0; 108 p->waiters = 0; 109 p->last_sem_post_tid = DRD_INVALID_THREADID; 110 p->last_sem_post_seg = VG_(newXA)(VG_(malloc), "drd.sg-stack", 111 VG_(free), sizeof(Segment*)); 112} 113 114/** 115 * Free the memory that was allocated by semaphore_initialize(). Called by 116 * DRD_(clientobj_remove)(). 117 */ 118static void semaphore_cleanup(struct semaphore_info* p) 119{ 120 Segment* sg; 121 122 if (p->waiters > 0) 123 { 124 SemaphoreErrInfo sei = { DRD_(thread_get_running_tid)(), p->a1 }; 125 VG_(maybe_record_error)(VG_(get_running_tid)(), 126 SemaphoreErr, 127 VG_(get_IP)(VG_(get_running_tid)()), 128 "Destruction of semaphore that is being waited" 129 " upon", 130 &sei); 131 } 132 while ((sg = drd_segment_pop(p))) 133 DRD_(sg_put)(sg); 134 VG_(deleteXA)(p->last_sem_post_seg); 135} 136 137/** 138 * Return a pointer to the structure with information about the specified 139 * client semaphore. Allocate a new structure if such a structure did not 140 * yet exist. 141 */ 142static 143struct semaphore_info* 144drd_semaphore_get_or_allocate(const Addr semaphore) 145{ 146 struct semaphore_info *p; 147 148 tl_assert(offsetof(DrdClientobj, semaphore) == 0); 149 p = &(DRD_(clientobj_get)(semaphore, ClientSemaphore)->semaphore); 150 if (p == 0) 151 { 152 tl_assert(offsetof(DrdClientobj, semaphore) == 0); 153 p = &(DRD_(clientobj_add)(semaphore, ClientSemaphore)->semaphore); 154 drd_semaphore_initialize(p, semaphore); 155 } 156 return p; 157} 158 159/** 160 * Return a pointer to the structure with information about the specified 161 * client semaphore, or null if no such structure was found. 162 */ 163static struct semaphore_info* semaphore_get(const Addr semaphore) 164{ 165 tl_assert(offsetof(DrdClientobj, semaphore) == 0); 166 return &(DRD_(clientobj_get)(semaphore, ClientSemaphore)->semaphore); 167} 168 169/** Called before sem_init(). */ 170struct semaphore_info* DRD_(semaphore_init)(const Addr semaphore, 171 const Word pshared, 172 const UInt value) 173{ 174 struct semaphore_info* p; 175 Segment* sg; 176 177 if (s_trace_semaphore) 178 { 179 VG_(message)(Vg_UserMsg, 180 "[%d] sem_init 0x%lx value %u\n", 181 DRD_(thread_get_running_tid)(), 182 semaphore, 183 value); 184 } 185 p = semaphore_get(semaphore); 186 if (p) 187 { 188 const ThreadId vg_tid = VG_(get_running_tid)(); 189 SemaphoreErrInfo SEI = { DRD_(thread_get_running_tid)(), semaphore }; 190 VG_(maybe_record_error)(vg_tid, 191 SemaphoreErr, 192 VG_(get_IP)(vg_tid), 193 "Semaphore reinitialization", 194 &SEI); 195 // Remove all segments from the segment stack. 196 while ((sg = drd_segment_pop(p))) 197 { 198 DRD_(sg_put)(sg); 199 } 200 } 201 else 202 { 203#if defined(VGO_darwin) 204 const ThreadId vg_tid = VG_(get_running_tid)(); 205 GenericErrInfo GEI = { DRD_(thread_get_running_tid)() }; 206 VG_(maybe_record_error)(vg_tid, 207 GenericErr, 208 VG_(get_IP)(vg_tid), 209 "sem_init() is not yet supported on Darwin", 210 &GEI); 211 return NULL; 212#else 213 p = drd_semaphore_get_or_allocate(semaphore); 214#endif 215 } 216 tl_assert(p); 217 p->waits_to_skip = value; 218 p->value = value; 219 return p; 220} 221 222/** Called after sem_destroy(). */ 223void DRD_(semaphore_destroy)(const Addr semaphore) 224{ 225 struct semaphore_info* p; 226 227 p = semaphore_get(semaphore); 228 229 if (s_trace_semaphore) 230 { 231 VG_(message)(Vg_UserMsg, 232 "[%d] sem_destroy 0x%lx value %u\n", 233 DRD_(thread_get_running_tid)(), 234 semaphore, 235 p ? p->value : 0); 236 } 237 238 if (p == 0) 239 { 240 GenericErrInfo GEI = { DRD_(thread_get_running_tid)() }; 241 VG_(maybe_record_error)(VG_(get_running_tid)(), 242 GenericErr, 243 VG_(get_IP)(VG_(get_running_tid)()), 244 "Not a semaphore", 245 &GEI); 246 return; 247 } 248 249 DRD_(clientobj_remove)(semaphore, ClientSemaphore); 250} 251 252/** Called after sem_open(). */ 253struct semaphore_info* DRD_(semaphore_open)(const Addr semaphore, 254 const Char* name, const Word oflag, 255 const Word mode, const UInt value) 256{ 257 struct semaphore_info* p; 258 Segment* sg; 259 260 if (s_trace_semaphore) 261 { 262 VG_(message)(Vg_UserMsg, 263 "[%d] sem_open 0x%lx name %s" 264 " oflag %ld mode 0x%lx value %u\n", 265 DRD_(thread_get_running_tid)(), 266 semaphore, name, oflag, mode, value); 267 } 268 269 /* Return if the sem_open() call failed. */ 270 if (! semaphore) 271 return NULL; 272 273 p = semaphore_get(semaphore); 274 if (p) 275 { 276 const ThreadId vg_tid = VG_(get_running_tid)(); 277 SemaphoreErrInfo SEI = { DRD_(thread_get_running_tid)(), semaphore }; 278 VG_(maybe_record_error)(vg_tid, 279 SemaphoreErr, 280 VG_(get_IP)(vg_tid), 281 "Semaphore reinitialization", 282 &SEI); 283 // Remove all segments from the segment stack. 284 while ((sg = drd_segment_pop(p))) 285 { 286 DRD_(sg_put)(sg); 287 } 288 } 289 else 290 { 291 p = drd_semaphore_get_or_allocate(semaphore); 292 } 293 tl_assert(p); 294 p->waits_to_skip = value; 295 p->value = value; 296 return p; 297} 298 299/** Called before sem_close(). */ 300void DRD_(semaphore_close)(const Addr semaphore) 301{ 302 struct semaphore_info* p; 303 304 p = semaphore_get(semaphore); 305 306 if (s_trace_semaphore) 307 { 308 VG_(message)(Vg_UserMsg, 309 "[%d] sem_close 0x%lx value %u\n", 310 DRD_(thread_get_running_tid)(), 311 semaphore, 312 p ? p->value : 0); 313 } 314 315 if (p == 0) 316 { 317 GenericErrInfo GEI = { DRD_(thread_get_running_tid)() }; 318 VG_(maybe_record_error)(VG_(get_running_tid)(), 319 GenericErr, 320 VG_(get_IP)(VG_(get_running_tid)()), 321 "Not a semaphore", 322 &GEI); 323 return; 324 } 325 326 DRD_(clientobj_remove)(semaphore, ClientSemaphore); 327} 328 329/** Called before sem_wait(). */ 330void DRD_(semaphore_pre_wait)(const Addr semaphore) 331{ 332 struct semaphore_info* p; 333 334 p = drd_semaphore_get_or_allocate(semaphore); 335 tl_assert(p); 336 p->waiters++; 337 338 if ((Word)(p->waiters) <= 0) 339 { 340 SemaphoreErrInfo sei = { DRD_(thread_get_running_tid)(), semaphore }; 341 VG_(maybe_record_error)(VG_(get_running_tid)(), 342 SemaphoreErr, 343 VG_(get_IP)(VG_(get_running_tid)()), 344 "Invalid semaphore", 345 &sei); 346 } 347} 348 349/** 350 * Called after sem_wait() finished. 351 * @note Do not rely on the value of 'waited' -- some glibc versions do 352 * not set it correctly. 353 */ 354void DRD_(semaphore_post_wait)(const DrdThreadId tid, const Addr semaphore, 355 const Bool waited) 356{ 357 struct semaphore_info* p; 358 Segment* sg; 359 360 p = semaphore_get(semaphore); 361 if (s_trace_semaphore) 362 { 363 VG_(message)(Vg_UserMsg, 364 "[%d] sem_wait 0x%lx value %u -> %u\n", 365 DRD_(thread_get_running_tid)(), 366 semaphore, 367 p ? p->value : 0, 368 p ? p->value - 1 : 0); 369 } 370 371 if (p) 372 { 373 p->waiters--; 374 p->value--; 375 } 376 377 /* 378 * Note: if another thread destroyed and reinitialized a semaphore while 379 * the current thread was waiting in sem_wait, p->waiters may have been 380 * set to zero by drd_semaphore_initialize() after 381 * DRD_(semaphore_pre_wait)() has finished before 382 * DRD_(semaphore_post_wait)() has been called. 383 */ 384 if (p == NULL || (Int)(p->value) < 0 || (Word)(p->waiters) < 0) 385 { 386 SemaphoreErrInfo sei = { DRD_(thread_get_running_tid)(), semaphore }; 387 VG_(maybe_record_error)(VG_(get_running_tid)(), 388 SemaphoreErr, 389 VG_(get_IP)(VG_(get_running_tid)()), 390 "Invalid semaphore", 391 &sei); 392 return; 393 } 394 395 if (p->waits_to_skip > 0) 396 p->waits_to_skip--; 397 else 398 { 399 sg = drd_segment_pop(p); 400 tl_assert(sg); 401 if (sg) 402 { 403 if (p->last_sem_post_tid != tid 404 && p->last_sem_post_tid != DRD_INVALID_THREADID) 405 { 406 DRD_(thread_new_segment_and_combine_vc)(tid, sg); 407 } 408 else 409 DRD_(thread_new_segment)(tid); 410 s_semaphore_segment_creation_count++; 411 DRD_(sg_put)(sg); 412 } 413 } 414} 415 416/** Called before sem_post(). */ 417void DRD_(semaphore_pre_post)(const DrdThreadId tid, const Addr semaphore) 418{ 419 struct semaphore_info* p; 420 Segment* sg; 421 422 p = drd_semaphore_get_or_allocate(semaphore); 423 p->value++; 424 425 if (s_trace_semaphore) 426 { 427 VG_(message)(Vg_UserMsg, 428 "[%d] sem_post 0x%lx value %u -> %u\n", 429 DRD_(thread_get_running_tid)(), 430 semaphore, 431 p->value - 1, p->value); 432 } 433 434 p->last_sem_post_tid = tid; 435 sg = 0; 436 DRD_(thread_get_latest_segment)(&sg, tid); 437 tl_assert(sg); 438 drd_segment_push(p, sg); 439 DRD_(thread_new_segment)(tid); 440 s_semaphore_segment_creation_count++; 441} 442 443/** Called after sem_post() finished. */ 444void DRD_(semaphore_post_post)(const DrdThreadId tid, const Addr semaphore, 445 const Bool succeeded) 446{ 447 /* 448 * Note: it is hard to implement the sem_post() wrapper correctly in 449 * case sem_post() returns an error code. This is because handling this 450 * case correctly requires restoring the vector clock associated with 451 * the semaphore to its original value here. In order to do that without 452 * introducing a race condition, extra locking has to be added around 453 * each semaphore call. Such extra locking would have to be added in 454 * drd_pthread_intercepts.c. However, it is hard to implement 455 * synchronization in drd_pthread_intercepts.c in a portable way without 456 * calling already redirected functions. 457 */ 458} 459 460ULong DRD_(get_semaphore_segment_creation_count)(void) 461{ 462 return s_semaphore_segment_creation_count; 463} 464