mono/io-layer/threads.c

   1 #include <config.h>
   2 #if HAVE_BOEHM_GC
   3 #include <gc/gc.h>
   4 #include "mono/utils/mono-hash.h"
   5 #endif
   6 #include <glib.h>
   7 #include <string.h>
   8 #include <pthread.h>
   9 #include <sched.h>
  10 #include <sys/time.h>
  11 #include <errno.h>
  12
  13 #include "mono/io-layer/wapi.h"
  14 #include "wapi-private.h"
  15 #include "timed-thread.h"
  16 #include "wait-private.h"
  17 #include "handles-private.h"
  18 #include "misc-private.h"
  19
  20 #include "mono-mutex.h"
  21
  22 #undef DEBUG
  23
  24 typedef enum {
  25         THREAD_STATE_START,
  26         THREAD_STATE_EXITED,
  27 } WapiThreadState;
  28
  29 struct _WapiHandle_thread
  30 {
  31         WapiHandle handle;
  32         WapiThreadState state;
  33         TimedThread *thread;
  34         guint32 exitstatus;
  35 };
  36
  37 static mono_mutex_t thread_signal_mutex = MONO_MUTEX_INITIALIZER;
  38 static pthread_cond_t thread_signal_cond = PTHREAD_COND_INITIALIZER;
  39
  40 /* Hash threads with tids. I thought of using TLS for this, but that
  41  * would have to set the data in the new thread, which is more hassle
  42  */
  43 static pthread_once_t thread_hash_once = PTHREAD_ONCE_INIT;
  44 static mono_mutex_t thread_hash_mutex = MONO_MUTEX_INITIALIZER;
  45 static GHashTable *thread_hash=NULL;
  46
  47 #if HAVE_BOEHM_GC
  48 static MonoGHashTable *tls_gc_hash = NULL;
  49 #endif
  50
  51 static void thread_close(WapiHandle *handle);
  52 static gboolean thread_wait(WapiHandle *handle, WapiHandle *signal,
  53                             guint32 ms);
  54 static guint32 thread_wait_multiple(gpointer data);
  55
  56 static struct _WapiHandleOps thread_ops = {
  57         thread_close,                   /* close */
  58         NULL,                           /* getfiletype */
  59         NULL,                           /* readfile */
  60         NULL,                           /* writefile */
  61         NULL,                           /* flushfile */
  62         NULL,                           /* seek */
  63         NULL,                           /* setendoffile */
  64         NULL,                           /* getfilesize */
  65         NULL,                           /* getfiletime */
  66         NULL,                           /* setfiletime */
  67         thread_wait,                    /* wait */
  68         thread_wait_multiple,           /* wait_multiple */
  69         NULL,                           /* signal */
  70 };
  71
  72 static void thread_close(WapiHandle *handle)
  73 {
  74         struct _WapiHandle_thread *thread_handle=(struct _WapiHandle_thread *)handle;
  75
  76 #ifdef DEBUG
  77         g_message(G_GNUC_PRETTY_FUNCTION
  78                   ": closing thread handle %p with thread %p id %ld",
  79                   thread_handle, thread_handle->thread,
  80                   thread_handle->thread->id);
  81 #endif
  82
  83         g_free(thread_handle->thread);
  84 }
  85
  86 static gboolean thread_wait(WapiHandle *handle, WapiHandle *signal, guint32 ms)
  87 {
  88         struct _WapiHandle_thread *thread_handle=(struct _WapiHandle_thread *)handle;
  89         int ret;
  90
  91         /* A thread can never become unsignalled after it was
  92          * signalled, so we can signal this handle now without
  93          * worrying about lost wakeups
  94          */
  95         if(signal!=NULL) {
  96                 signal->ops->signal(signal);
  97         }
  98
  99         if(handle->signalled==TRUE) {
 100                 /* Already signalled, so return straight away */
 101 #ifdef DEBUG
 102                 g_message(G_GNUC_PRETTY_FUNCTION ": thread handle %p already signalled, returning now", handle);
 103 #endif
 104
 105                 return(TRUE);
 106         }
 107
 108 #ifdef DEBUG
 109         g_message(G_GNUC_PRETTY_FUNCTION
 110                   ": waiting for %d ms for thread handle %p with id %ld", ms,
 111                   thread_handle, thread_handle->thread->id);
 112 #endif
 113
 114         if(ms==INFINITE) {
 115                 ret=_wapi_timed_thread_join(thread_handle->thread, NULL, NULL);
 116         } else {
 117                 struct timespec timeout;
 118
 119                 _wapi_calc_timeout(&timeout, ms);
 120
 121                 ret=_wapi_timed_thread_join(thread_handle->thread, &timeout,
 122                                             NULL);
 123         }
 124
 125         if(ret==0) {
 126                 /* Thread joined */
 127                 return(TRUE);
 128         } else {
 129                 /* ret might be ETIMEDOUT for timeout, or other for error */
 130                 return(FALSE);
 131         }
 132 }
 133
 134 static guint32 thread_wait_multiple(gpointer data)
 135 {
 136         WaitQueueItem *item=(WaitQueueItem *)data;
 137         int ret;
 138         guint32 numhandles, count;
 139         struct timespec timeout;
 140
 141         numhandles=item->handles[WAPI_HANDLE_THREAD]->len;
 142
 143 #ifdef DEBUG
 144         g_message(G_GNUC_PRETTY_FUNCTION
 145                   ": waiting on %d thread handles for %d ms", numhandles,
 146                   item->timeout);
 147 #endif
 148
 149         /* First, check if any of the handles are already
 150          * signalled. If waitall is specified we only return if all
 151          * handles have been signalled.
 152          */
 153         count=_wapi_handle_count_signalled(item, WAPI_HANDLE_THREAD);
 154
 155 #ifdef DEBUG
 156         g_message(G_GNUC_PRETTY_FUNCTION
 157                   ": Preliminary check found %d handles signalled", count);
 158 #endif
 159
 160         if((item->waitall==TRUE && count==numhandles) ||
 161            (item->waitall==FALSE && count>0)) {
 162                 goto success;
 163         }
 164
 165         /* OK, we need to wait for some */
 166         if(item->timeout!=INFINITE) {
 167                 _wapi_calc_timeout(&timeout, item->timeout);
 168         }
 169
 170         /* We can restart from here without resetting the timeout,
 171          * because it is calculated from absolute time, not an offset
 172          */
 173 again:
 174         mono_mutex_lock(&thread_signal_mutex);
 175         if(item->timeout==INFINITE) {
 176                 ret=mono_cond_wait(&thread_signal_cond,
 177                                       &thread_signal_mutex);
 178         } else {
 179                 ret=mono_cond_timedwait(&thread_signal_cond,
 180                                            &thread_signal_mutex,
 181                                            &timeout);
 182         }
 183         mono_mutex_unlock(&thread_signal_mutex);
 184
 185         if(ret==ETIMEDOUT) {
 186                 /* Check signalled state here, just in case a thread
 187                  * exited between the first check and the cond wait.
 188                  * We return the number of signalled handles, which
 189                  * may be fewer than the total.
 190                  */
 191 #ifdef DEBUG
 192                 g_message(G_GNUC_PRETTY_FUNCTION ": Wait timed out");
 193 #endif
 194
 195                 count=_wapi_handle_count_signalled(item, WAPI_HANDLE_THREAD);
 196                 goto success;
 197         }
 198
 199 #ifdef DEBUG
 200         g_message(G_GNUC_PRETTY_FUNCTION ": Thread exited, checking status");
 201 #endif
 202
 203         /* Another thread exited, so see if it was one we are
 204          * interested in
 205          */
 206         count=_wapi_handle_count_signalled(item, WAPI_HANDLE_THREAD);
 207
 208 #ifdef DEBUG
 209         g_message(G_GNUC_PRETTY_FUNCTION
 210                   ": Check after thread exit found %d handles signalled",
 211                   count);
 212 #endif
 213
 214         if((item->waitall==TRUE && count==numhandles) ||
 215            (item->waitall==FALSE && count>0)) {
 216                 goto success;
 217         }
 218
 219         /* Either we have waitall set with more handles to wait for,
 220          * or the thread that exited wasn't interesting to us
 221          */
 222 #ifdef DEBUG
 223         g_message(G_GNUC_PRETTY_FUNCTION ": Waiting a bit longer");
 224 #endif
 225
 226         goto again;
 227
 228 success:
 229         item->waited[WAPI_HANDLE_THREAD]=TRUE;
 230         item->waitcount[WAPI_HANDLE_THREAD]=count;
 231
 232         return(count);
 233 }
 234
 235 static void thread_exit(guint32 exitstatus, gpointer userdata)
 236 {
 237         struct _WapiHandle_thread *thread_handle=(struct _WapiHandle_thread *)userdata;
 238
 239         thread_handle->exitstatus=exitstatus;
 240         thread_handle->state=THREAD_STATE_EXITED;
 241         thread_handle->handle.signalled=TRUE;
 242
 243 #ifdef DEBUG
 244         g_message(G_GNUC_PRETTY_FUNCTION
 245                   ": Recording thread handle %p id %ld status as %d",
 246                   thread_handle, thread_handle->thread->id, exitstatus);
 247 #endif
 248
 249         /* Remove this thread from the hash */
 250         mono_mutex_lock(&thread_hash_mutex);
 251         g_hash_table_remove(thread_hash, &thread_handle->thread->id);
 252         mono_mutex_unlock(&thread_hash_mutex);
 253
 254         /* Signal any thread waiting on thread exit */
 255         mono_mutex_lock(&thread_signal_mutex);
 256         pthread_cond_broadcast(&thread_signal_cond);
 257         mono_mutex_unlock(&thread_signal_mutex);
 258 }
 259
 260 static void thread_hash_init(void)
 261 {
 262         thread_hash=g_hash_table_new(g_int_hash, g_int_equal);
 263 }
 264
 265 /**
 266  * CreateThread:
 267  * @security: Ignored for now.
 268  * @stacksize: the size in bytes of the new thread's stack. Use 0 to
 269  * default to the normal stack size. (Ignored for now).
 270  * @start: The function that the new thread should start with
 271  * @param: The parameter to give to @start.
 272  * @create: If 0, the new thread is ready to run immediately.  If
 273  * %CREATE_SUSPENDED, the new thread will be in the suspended state,
 274  * requiring a ResumeThread() call to continue running.
 275  * @tid: If non-NULL, the ID of the new thread is stored here.
 276  *
 277  * Creates a new threading handle.
 278  *
 279  * Return value: a new handle, or NULL
 280  */
 281 WapiHandle *CreateThread(WapiSecurityAttributes *security G_GNUC_UNUSED, guint32 stacksize G_GNUC_UNUSED,
 282                          WapiThreadStart start, gpointer param, guint32 create G_GNUC_UNUSED,
 283                          guint32 *tid)
 284 {
 285         struct _WapiHandle_thread *thread_handle;
 286         WapiHandle *handle;
 287         int ret;
 288
 289         pthread_once(&thread_hash_once, thread_hash_init);
 290
 291         if(start==NULL) {
 292                 return(NULL);
 293         }
 294
 295         thread_handle=(struct _WapiHandle_thread *)g_new0(struct _WapiHandle_thread, 1);
 296
 297         handle=(WapiHandle *)thread_handle;
 298         _WAPI_HANDLE_INIT(handle, WAPI_HANDLE_THREAD, thread_ops);
 299
 300         thread_handle->state=THREAD_STATE_START;
 301
 302         /* Lock around the thread create, so that the new thread cant
 303          * race us to look up the thread handle in GetCurrentThread()
 304          */
 305         mono_mutex_lock(&thread_hash_mutex);
 306
 307         ret=_wapi_timed_thread_create(&thread_handle->thread, NULL, start,
 308                                       thread_exit, param, thread_handle);
 309         if(ret!=0) {
 310 #ifdef DEBUG
 311                 g_message(G_GNUC_PRETTY_FUNCTION ": Thread create error: %s",
 312                           strerror(ret));
 313 #endif
 314                 mono_mutex_unlock(&thread_hash_mutex);
 315                 g_free(thread_handle);
 316                 return(NULL);
 317         }
 318
 319         g_hash_table_insert(thread_hash, &thread_handle->thread->id,
 320                             thread_handle);
 321         mono_mutex_unlock(&thread_hash_mutex);
 322
 323 #ifdef DEBUG
 324         g_message(G_GNUC_PRETTY_FUNCTION
 325                   ": Started thread handle %p thread %p ID %ld", thread_handle,
 326                   thread_handle->thread, thread_handle->thread->id);
 327 #endif
 328
 329         if(tid!=NULL) {
 330                 *tid=thread_handle->thread->id;
 331         }
 332
 333         return(handle);
 334 }
 335
 336 /**
 337  * ExitThread:
 338  * @exitcode: Sets the thread's exit code, which can be read from
 339  * another thread with GetExitCodeThread().
 340  *
 341  * Terminates the calling thread.  A thread can also exit by returning
 342  * from its start function. When the last thread in a process
 343  * terminates, the process itself terminates.
 344  */
 345 void ExitThread(guint32 exitcode)
 346 {
 347         _wapi_timed_thread_exit(exitcode);
 348 }
 349
 350 /**
 351  * GetExitCodeThread:
 352  * @handle: The thread handle to query
 353  * @exitcode: The thread @handle exit code is stored here
 354  *
 355  * Finds the exit code of @handle, and stores it in @exitcode.  If the
 356  * thread @handle is still running, the value stored is %STILL_ACTIVE.
 357  *
 358  * Return value: %TRUE, or %FALSE on error.
 359  */
 360 gboolean GetExitCodeThread(WapiHandle *handle, guint32 *exitcode)
 361 {
 362         struct _WapiHandle_thread *thread_handle=(struct _WapiHandle_thread *)handle;
 363
 364 #ifdef DEBUG
 365         g_message(G_GNUC_PRETTY_FUNCTION
 366                   ": Finding exit status for thread handle %p id %ld", handle,
 367                   thread_handle->thread->id);
 368 #endif
 369
 370         if(exitcode==NULL) {
 371 #ifdef DEBUG
 372                 g_message(G_GNUC_PRETTY_FUNCTION
 373                           ": Nowhere to store exit code");
 374 #endif
 375                 return(FALSE);
 376         }
 377
 378         if(thread_handle->state!=THREAD_STATE_EXITED) {
 379 #ifdef DEBUG
 380                 g_message(G_GNUC_PRETTY_FUNCTION
 381                           ": Thread still active (state %d, exited is %d)",
 382                           thread_handle->state, THREAD_STATE_EXITED);
 383 #endif
 384                 *exitcode=STILL_ACTIVE;
 385                 return(TRUE);
 386         }
 387
 388         *exitcode=thread_handle->exitstatus;
 389
 390         return(TRUE);
 391 }
 392
 393 /**
 394  * GetCurrentThreadId:
 395  *
 396  * Looks up the thread ID of the current thread.  This ID can be
 397  * passed to OpenThread() to create a new handle on this thread.
 398  *
 399  * Return value: the thread ID.
 400  */
 401 guint32 GetCurrentThreadId(void)
 402 {
 403         pthread_t tid=pthread_self();
 404
 405         return(tid);
 406 }
 407
 408 /**
 409  * GetCurrentThread:
 410  *
 411  * Looks up the handle associated with the current thread.  Under
 412  * Windows this is a pseudohandle, and must be duplicated with
 413  * DuplicateHandle() for some operations.
 414  *
 415  * Return value: The current thread handle, or %NULL on failure.
 416  * (Unknown whether Windows has a possible failure here.  It may be
 417  * necessary to implement the pseudohandle-constant behaviour).
 418  */
 419 WapiHandle *GetCurrentThread(void)
 420 {
 421         WapiHandle *ret=NULL;
 422         guint32 tid;
 423
 424         tid=GetCurrentThreadId();
 425
 426         mono_mutex_lock(&thread_hash_mutex);
 427
 428         ret=g_hash_table_lookup(thread_hash, &tid);
 429
 430         mono_mutex_unlock(&thread_hash_mutex);
 431
 432         return(ret);
 433 }
 434
 435 /**
 436  * ResumeThread:
 437  * @handle: the thread handle to resume
 438  *
 439  * Decrements the suspend count of thread @handle. A thread can only
 440  * run if its suspend count is zero.
 441  *
 442  * Return value: the previous suspend count, or 0xFFFFFFFF on error.
 443  */
 444 guint32 ResumeThread(WapiHandle *handle G_GNUC_UNUSED)
 445 {
 446         return(0xFFFFFFFF);
 447 }
 448
 449 /**
 450  * SuspendThread:
 451  * @handle: the thread handle to suspend
 452  *
 453  * Increments the suspend count of thread @handle. A thread can only
 454  * run if its suspend count is zero.
 455  *
 456  * Return value: the previous suspend count, or 0xFFFFFFFF on error.
 457  */
 458 guint32 SuspendThread(WapiHandle *handle G_GNUC_UNUSED)
 459 {
 460         return(0xFFFFFFFF);
 461 }
 462
 463 /*
 464  * We assume here that TLS_MINIMUM_AVAILABLE is less than
 465  * PTHREAD_KEYS_MAX, allowing enough overhead for a few TLS keys for
 466  * library usage.
 467  *
 468  * Currently TLS_MINIMUM_AVAILABLE is 64 and _POSIX_THREAD_KEYS_MAX
 469  * (the minimum value for PTHREAD_KEYS_MAX) is 128, so we should be
 470  * fine.
 471  */
 472
 473 static pthread_key_t TLS_keys[TLS_MINIMUM_AVAILABLE];
 474 static gboolean TLS_used[TLS_MINIMUM_AVAILABLE]={FALSE};
 475 static mono_mutex_t TLS_mutex=MONO_MUTEX_INITIALIZER;
 476
 477 /**
 478  * TlsAlloc:
 479  *
 480  * Allocates a Thread Local Storage (TLS) index.  Any thread in the
 481  * same process can use this index to store and retrieve values that
 482  * are local to that thread.
 483  *
 484  * Return value: The index value, or %TLS_OUT_OF_INDEXES if no index
 485  * is available.
 486  */
 487 guint32 TlsAlloc(void)
 488 {
 489         guint32 i;
 490
 491         mono_mutex_lock(&TLS_mutex);
 492
 493         for(i=0; i<TLS_MINIMUM_AVAILABLE; i++) {
 494                 if(TLS_used[i]==FALSE) {
 495                         TLS_used[i]=TRUE;
 496                         pthread_key_create(&TLS_keys[i], NULL);
 497
 498                         mono_mutex_unlock(&TLS_mutex);
 499
 500                         return(i);
 501                 }
 502         }
 503
 504         mono_mutex_unlock(&TLS_mutex);
 505
 506         return(TLS_OUT_OF_INDEXES);
 507 }
 508
 509 /**
 510  * TlsFree:
 511  * @idx: The TLS index to free
 512  *
 513  * Releases a TLS index, making it available for reuse.  This call
 514  * will delete any TLS data stored under index @idx in all threads.
 515  *
 516  * Return value: %TRUE on success, %FALSE otherwise.
 517  */
 518 gboolean TlsFree(guint32 idx)
 519 {
 520         mono_mutex_lock(&TLS_mutex);
 521
 522         if(TLS_used[idx]==FALSE) {
 523                 mono_mutex_unlock(&TLS_mutex);
 524                 return(FALSE);
 525         }
 526
 527         TLS_used[idx]=FALSE;
 528         pthread_key_delete(TLS_keys[idx]);
 529
 530 #if HAVE_BOEHM_GC
 531         mono_g_hash_table_remove (tls_gc_hash, GUINT_TO_POINTER (idx));
 532 #endif
 533         mono_mutex_unlock(&TLS_mutex);
 534
 535         return(TRUE);
 536 }
 537
 538 /**
 539  * TlsGetValue:
 540  * @idx: The TLS index to retrieve
 541  *
 542  * Retrieves the TLS data stored under index @idx.
 543  *
 544  * Return value: The value stored in the TLS index @idx in the current
 545  * thread, or %NULL on error.  As %NULL can be a valid return value,
 546  * in this case GetLastError() returns %ERROR_SUCCESS.
 547  */
 548 gpointer TlsGetValue(guint32 idx)
 549 {
 550         gpointer ret;
 551
 552         mono_mutex_lock(&TLS_mutex);
 553
 554         if(TLS_used[idx]==FALSE) {
 555                 mono_mutex_unlock(&TLS_mutex);
 556                 return(NULL);
 557         }
 558
 559         ret=pthread_getspecific(TLS_keys[idx]);
 560
 561         mono_mutex_unlock(&TLS_mutex);
 562
 563         return(ret);
 564 }
 565
 566 /**
 567  * TlsSetValue:
 568  * @idx: The TLS index to store
 569  * @value: The value to store under index @idx
 570  *
 571  * Stores @value at TLS index @idx.
 572  *
 573  * Return value: %TRUE on success, %FALSE otherwise.
 574  */
 575 gboolean TlsSetValue(guint32 idx, gpointer value)
 576 {
 577         int ret;
 578
 579         mono_mutex_lock(&TLS_mutex);
 580
 581         if(TLS_used[idx]==FALSE) {
 582                 mono_mutex_unlock(&TLS_mutex);
 583                 return(FALSE);
 584         }
 585
 586         ret=pthread_setspecific(TLS_keys[idx], value);
 587         if(ret!=0) {
 588                 mono_mutex_unlock(&TLS_mutex);
 589                 return(FALSE);
 590         }
 591
 592 #if HAVE_BOEHM_GC
 593         if (!tls_gc_hash)
 594                 tls_gc_hash = mono_g_hash_table_new(g_direct_hash, g_direct_equal);
 595         /* FIXME: index needs to encode the thread id, too */
 596         mono_g_hash_table_insert (tls_gc_hash, GUINT_TO_POINTER (idx), value);
 597 #endif
 598         mono_mutex_unlock(&TLS_mutex);
 599
 600         return(TRUE);
 601 }
 602
 603 /**
 604  * Sleep:
 605  * @ms: The time in milliseconds to suspend for
 606  *
 607  * Suspends execution of the current thread for @ms milliseconds.  A
 608  * value of zero causes the thread to relinquish its time slice.  A
 609  * value of %INFINITE causes an infinite delay.
 610  */
 611 void Sleep(guint32 ms)
 612 {
 613         struct timespec req, rem;
 614         div_t divvy;
 615         int ret;
 616
 617 #ifdef DEBUG
 618         g_message(G_GNUC_PRETTY_FUNCTION ": Sleeping for %d ms", ms);
 619 #endif
 620
 621         if(ms==0) {
 622                 sched_yield();
 623                 return;
 624         }
 625
 626         /* FIXME: check for INFINITE and sleep forever */
 627         divvy=div((int)ms, 1000);
 628
 629         req.tv_sec=divvy.quot;
 630         req.tv_nsec=divvy.rem*1000000;
 631
 632 again:
 633         ret=nanosleep(&req, &rem);
 634         if(ret==-1) {
 635                 /* Sleep interrupted with rem time remaining */
 636 #ifdef DEBUG
 637                 guint32 rems=rem.tv_sec*1000 + rem.tv_nsec/1000000;
 638
 639                 g_message(G_GNUC_PRETTY_FUNCTION ": Still got %d ms to go",
 640                           rems);
 641 #endif
 642                 req=rem;
 643                 goto again;
 644         }
 645 }
 646
 647 /* FIXME: implement alertable */
 648 void SleepEx(guint32 ms, gboolean alertable)
 649 {
 650         if(alertable==TRUE) {
 651                 g_warning(G_GNUC_PRETTY_FUNCTION ": alertable not implemented");
 652         }
 653
 654         Sleep(ms);
 655 }