server/thread.c

   1 /*
   2  * Server-side thread management
   3  *
   4  * Copyright (C) 1998 Alexandre Julliard
   5  */
   6
   7 #include "config.h"
   8
   9 #include <assert.h>
  10 #include <fcntl.h>
  11 #include <signal.h>
  12 #include <stdarg.h>
  13 #include <stdio.h>
  14 #include <stdlib.h>
  15 #include <string.h>
  16 #ifdef HAVE_SYS_MMAN_H
  17 #include <sys/mman.h>
  18 #endif
  19 #include <sys/types.h>
  20 #ifdef HAVE_SYS_SOCKET_H
  21 # include <sys/socket.h>
  22 #endif
  23 #include <sys/uio.h>
  24 #include <unistd.h>
  25 #include <stdarg.h>
  26
  27 #include "winbase.h"
  28
  29 #include "handle.h"
  30 #include "process.h"
  31 #include "thread.h"
  32 #include "request.h"
  33
  34
  35 /* thread queues */
  36
  37 struct thread_wait
  38 {
  39     int                     count;      /* count of objects */
  40     int                     flags;
  41     struct timeval          timeout;
  42     struct timeout_user    *user;
  43     struct wait_queue_entry queues[1];
  44 };
  45
  46 /* asynchronous procedure calls */
  47
  48 struct thread_apc
  49 {
  50     struct thread_apc  *next;     /* queue linked list */
  51     struct thread_apc  *prev;
  52     struct object      *owner;    /* object that queued this apc */
  53     void               *func;     /* function to call in client */
  54     enum apc_type       type;     /* type of apc function */
  55     int                 nb_args;  /* number of arguments */
  56     void               *args[1];  /* function arguments */
  57 };
  58
  59
  60 /* thread operations */
  61
  62 static void dump_thread( struct object *obj, int verbose );
  63 static int thread_signaled( struct object *obj, struct thread *thread );
  64 static void thread_poll_event( struct object *obj, int event );
  65 static void destroy_thread( struct object *obj );
  66 static struct thread_apc *thread_dequeue_apc( struct thread *thread, int system_only );
  67
  68 static const struct object_ops thread_ops =
  69 {
  70     sizeof(struct thread),      /* size */
  71     dump_thread,                /* dump */
  72     add_queue,                  /* add_queue */
  73     remove_queue,               /* remove_queue */
  74     thread_signaled,            /* signaled */
  75     no_satisfied,               /* satisfied */
  76     NULL,                       /* get_poll_events */
  77     thread_poll_event,          /* poll_event */
  78     no_get_fd,                  /* get_fd */
  79     no_flush,                   /* flush */
  80     no_get_file_info,           /* get_file_info */
  81     destroy_thread              /* destroy */
  82 };
  83
  84 static struct thread *first_thread;
  85 static struct thread *booting_thread;
  86
  87 /* allocate the buffer for the communication with the client */
  88 static int alloc_client_buffer( struct thread *thread )
  89 {
  90     union generic_request *req;
  91     int fd = -1, fd_pipe[2], wait_pipe[2];
  92
  93     wait_pipe[0] = wait_pipe[1] = -1;
  94     if (pipe( fd_pipe ) == -1)
  95     {
  96         file_set_error();
  97         return 0;
  98     }
  99     if (pipe( wait_pipe ) == -1) goto error;
 100     if ((fd = create_anonymous_file()) == -1) goto error;
 101     if (ftruncate( fd, MAX_REQUEST_LENGTH ) == -1) goto error;
 102     if ((thread->buffer = mmap( 0, MAX_REQUEST_LENGTH, PROT_READ | PROT_WRITE,
 103                                 MAP_SHARED, fd, 0 )) == (void*)-1) goto error;
 104     if (!(thread->request_fd = create_request_socket( thread ))) goto error;
 105     thread->reply_fd = fd_pipe[1];
 106     thread->wait_fd  = wait_pipe[1];
 107
 108     /* make the pipes non-blocking */
 109     fcntl( fd_pipe[1], F_SETFL, O_NONBLOCK );
 110     fcntl( wait_pipe[1], F_SETFL, O_NONBLOCK );
 111
 112     /* build the first request into the buffer and send it */
 113     req = thread->buffer;
 114     req->get_thread_buffer.pid  = get_process_id( thread->process );
 115     req->get_thread_buffer.tid  = get_thread_id( thread );
 116     req->get_thread_buffer.boot = (thread == booting_thread);
 117     req->get_thread_buffer.version = SERVER_PROTOCOL_VERSION;
 118
 119     /* add it here since send_client_fd may call kill_thread */
 120     add_process_thread( thread->process, thread );
 121
 122     send_client_fd( thread, fd_pipe[0], 0 );
 123     send_client_fd( thread, wait_pipe[0], 0 );
 124     send_client_fd( thread, fd, 0 );
 125     send_reply( thread, req );
 126     close( fd_pipe[0] );
 127     close( wait_pipe[0] );
 128     close( fd );
 129
 130     return 1;
 131
 132  error:
 133     file_set_error();
 134     if (fd != -1) close( fd );
 135     close( fd_pipe[0] );
 136     close( fd_pipe[1] );
 137     if (wait_pipe[0] != -1) close( wait_pipe[0] );
 138     if (wait_pipe[1] != -1) close( wait_pipe[1] );
 139     return 0;
 140 }
 141
 142 /* initialize the structure for a newly allocated thread */
 143 inline static void init_thread_structure( struct thread *thread )
 144 {
 145     int i;
 146
 147     thread->unix_pid        = 0;  /* not known yet */
 148     thread->context         = NULL;
 149     thread->teb             = NULL;
 150     thread->mutex           = NULL;
 151     thread->debug_ctx       = NULL;
 152     thread->debug_event     = NULL;
 153     thread->queue           = NULL;
 154     thread->info            = NULL;
 155     thread->wait            = NULL;
 156     thread->system_apc.head = NULL;
 157     thread->system_apc.tail = NULL;
 158     thread->user_apc.head   = NULL;
 159     thread->user_apc.tail   = NULL;
 160     thread->error           = 0;
 161     thread->request_fd      = NULL;
 162     thread->reply_fd        = -1;
 163     thread->wait_fd         = -1;
 164     thread->state           = RUNNING;
 165     thread->attached        = 0;
 166     thread->exit_code       = 0;
 167     thread->next            = NULL;
 168     thread->prev            = NULL;
 169     thread->priority        = THREAD_PRIORITY_NORMAL;
 170     thread->affinity        = 1;
 171     thread->suspend         = 0;
 172     thread->buffer          = (void *)-1;
 173     thread->last_req        = REQ_get_thread_buffer;
 174
 175     for (i = 0; i < MAX_INFLIGHT_FDS; i++)
 176         thread->inflight[i].server = thread->inflight[i].client = -1;
 177 }
 178
 179 /* create a new thread */
 180 struct thread *create_thread( int fd, struct process *process )
 181 {
 182     struct thread *thread;
 183
 184     int flags = fcntl( fd, F_GETFL, 0 );
 185     fcntl( fd, F_SETFL, flags | O_NONBLOCK );
 186
 187     if (!(thread = alloc_object( &thread_ops, fd ))) return NULL;
 188
 189     init_thread_structure( thread );
 190
 191     thread->process = (struct process *)grab_object( process );
 192     if (!current) current = thread;
 193
 194     if (!booting_thread)  /* first thread ever */
 195     {
 196         booting_thread = thread;
 197         lock_master_socket(1);
 198     }
 199
 200     if ((thread->next = first_thread) != NULL) thread->next->prev = thread;
 201     first_thread = thread;
 202
 203 #if 0
 204     set_select_events( &thread->obj, POLLIN );  /* start listening to events */
 205 #endif
 206     if (!alloc_client_buffer( thread )) goto error;
 207     return thread;
 208
 209  error:
 210     release_object( thread );
 211     return NULL;
 212 }
 213
 214 /* handle a client event */
 215 static void thread_poll_event( struct object *obj, int event )
 216 {
 217     struct thread *thread = (struct thread *)obj;
 218     assert( obj->ops == &thread_ops );
 219
 220     if (event & (POLLERR | POLLHUP)) kill_thread( thread, 0 );
 221 #if 0
 222     else if (event & POLLIN) read_request( thread );
 223 #endif
 224 }
 225
 226 /* cleanup everything that is no longer needed by a dead thread */
 227 /* used by destroy_thread and kill_thread */
 228 static void cleanup_thread( struct thread *thread )
 229 {
 230     int i;
 231     struct thread_apc *apc;
 232
 233     while ((apc = thread_dequeue_apc( thread, 0 ))) free( apc );
 234     if (thread->buffer != (void *)-1) munmap( thread->buffer, MAX_REQUEST_LENGTH );
 235     if (thread->reply_fd != -1) close( thread->reply_fd );
 236     if (thread->wait_fd != -1) close( thread->wait_fd );
 237     if (thread->request_fd) release_object( thread->request_fd );
 238     for (i = 0; i < MAX_INFLIGHT_FDS; i++)
 239     {
 240         if (thread->inflight[i].client != -1)
 241         {
 242             close( thread->inflight[i].server );
 243             thread->inflight[i].client = thread->inflight[i].server = -1;
 244         }
 245     }
 246     thread->buffer = (void *)-1;
 247     thread->reply_fd = -1;
 248     thread->wait_fd = -1;
 249     thread->request_fd = NULL;
 250 }
 251
 252 /* destroy a thread when its refcount is 0 */
 253 static void destroy_thread( struct object *obj )
 254 {
 255     struct thread_apc *apc;
 256     struct thread *thread = (struct thread *)obj;
 257     assert( obj->ops == &thread_ops );
 258
 259     assert( !thread->debug_ctx );  /* cannot still be debugging something */
 260     release_object( thread->process );
 261     if (thread->next) thread->next->prev = thread->prev;
 262     if (thread->prev) thread->prev->next = thread->next;
 263     else first_thread = thread->next;
 264     while ((apc = thread_dequeue_apc( thread, 0 ))) free( apc );
 265     if (thread->info) release_object( thread->info );
 266     if (thread->queue) release_object( thread->queue );
 267     cleanup_thread( thread );
 268 }
 269
 270 /* dump a thread on stdout for debugging purposes */
 271 static void dump_thread( struct object *obj, int verbose )
 272 {
 273     struct thread *thread = (struct thread *)obj;
 274     assert( obj->ops == &thread_ops );
 275
 276     fprintf( stderr, "Thread pid=%d teb=%p state=%d\n",
 277              thread->unix_pid, thread->teb, thread->state );
 278 }
 279
 280 static int thread_signaled( struct object *obj, struct thread *thread )
 281 {
 282     struct thread *mythread = (struct thread *)obj;
 283     return (mythread->state == TERMINATED);
 284 }
 285
 286 /* get a thread pointer from a thread id (and increment the refcount) */
 287 struct thread *get_thread_from_id( void *id )
 288 {
 289     struct thread *t = first_thread;
 290     while (t && (t != id)) t = t->next;
 291     if (t) grab_object( t );
 292     return t;
 293 }
 294
 295 /* get a thread from a handle (and increment the refcount) */
 296 struct thread *get_thread_from_handle( handle_t handle, unsigned int access )
 297 {
 298     return (struct thread *)get_handle_obj( current->process, handle,
 299                                             access, &thread_ops );
 300 }
 301
 302 /* find a thread from a Unix pid */
 303 struct thread *get_thread_from_pid( int pid )
 304 {
 305     struct thread *t = first_thread;
 306     while (t && (t->unix_pid != pid)) t = t->next;
 307     return t;
 308 }
 309
 310 /* set all information about a thread */
 311 static void set_thread_info( struct thread *thread,
 312                              struct set_thread_info_request *req )
 313 {
 314     if (req->mask & SET_THREAD_INFO_PRIORITY)
 315         thread->priority = req->priority;
 316     if (req->mask & SET_THREAD_INFO_AFFINITY)
 317     {
 318         if (req->affinity != 1) set_error( STATUS_INVALID_PARAMETER );
 319         else thread->affinity = req->affinity;
 320     }
 321 }
 322
 323 /* suspend a thread */
 324 int suspend_thread( struct thread *thread, int check_limit )
 325 {
 326     int old_count = thread->suspend;
 327     if (thread->suspend < MAXIMUM_SUSPEND_COUNT || !check_limit)
 328     {
 329         if (!(thread->process->suspend + thread->suspend++)) stop_thread( thread );
 330     }
 331     else set_error( STATUS_SUSPEND_COUNT_EXCEEDED );
 332     return old_count;
 333 }
 334
 335 /* resume a thread */
 336 int resume_thread( struct thread *thread )
 337 {
 338     int old_count = thread->suspend;
 339     if (thread->suspend > 0)
 340     {
 341         if (!(--thread->suspend + thread->process->suspend)) continue_thread( thread );
 342     }
 343     return old_count;
 344 }
 345
 346 /* suspend all threads but the current */
 347 void suspend_all_threads( void )
 348 {
 349     struct thread *thread;
 350     for ( thread = first_thread; thread; thread = thread->next )
 351         if ( thread != current )
 352             suspend_thread( thread, 0 );
 353 }
 354
 355 /* resume all threads but the current */
 356 void resume_all_threads( void )
 357 {
 358     struct thread *thread;
 359     for ( thread = first_thread; thread; thread = thread->next )
 360         if ( thread != current )
 361             resume_thread( thread );
 362 }
 363
 364 /* add a thread to an object wait queue; return 1 if OK, 0 on error */
 365 int add_queue( struct object *obj, struct wait_queue_entry *entry )
 366 {
 367     grab_object( obj );
 368     entry->obj    = obj;
 369     entry->prev   = obj->tail;
 370     entry->next   = NULL;
 371     if (obj->tail) obj->tail->next = entry;
 372     else obj->head = entry;
 373     obj->tail = entry;
 374     return 1;
 375 }
 376
 377 /* remove a thread from an object wait queue */
 378 void remove_queue( struct object *obj, struct wait_queue_entry *entry )
 379 {
 380     if (entry->next) entry->next->prev = entry->prev;
 381     else obj->tail = entry->prev;
 382     if (entry->prev) entry->prev->next = entry->next;
 383     else obj->head = entry->next;
 384     release_object( obj );
 385 }
 386
 387 /* finish waiting */
 388 static void end_wait( struct thread *thread )
 389 {
 390     struct thread_wait *wait = thread->wait;
 391     struct wait_queue_entry *entry;
 392     int i;
 393
 394     assert( wait );
 395     for (i = 0, entry = wait->queues; i < wait->count; i++, entry++)
 396         entry->obj->ops->remove_queue( entry->obj, entry );
 397     if (wait->user) remove_timeout_user( wait->user );
 398     free( wait );
 399     thread->wait = NULL;
 400 }
 401
 402 /* build the thread wait structure */
 403 static int wait_on( int count, struct object *objects[], int flags, int sec, int usec )
 404 {
 405     struct thread_wait *wait;
 406     struct wait_queue_entry *entry;
 407     int i;
 408
 409     if (!(wait = mem_alloc( sizeof(*wait) + (count-1) * sizeof(*entry) ))) return 0;
 410     current->wait = wait;
 411     wait->count   = count;
 412     wait->flags   = flags;
 413     wait->user    = NULL;
 414     if (flags & SELECT_TIMEOUT)
 415     {
 416         wait->timeout.tv_sec = sec;
 417         wait->timeout.tv_usec = usec;
 418     }
 419
 420     for (i = 0, entry = wait->queues; i < count; i++, entry++)
 421     {
 422         struct object *obj = objects[i];
 423         entry->thread = current;
 424         if (!obj->ops->add_queue( obj, entry ))
 425         {
 426             wait->count = i;
 427             end_wait( current );
 428             return 0;
 429         }
 430     }
 431     return 1;
 432 }
 433
 434 /* check if the thread waiting condition is satisfied */
 435 static int check_wait( struct thread *thread )
 436 {
 437     int i, signaled;
 438     struct thread_wait *wait = thread->wait;
 439     struct wait_queue_entry *entry = wait->queues;
 440
 441     assert( wait );
 442     if (wait->flags & SELECT_ALL)
 443     {
 444         int not_ok = 0;
 445         /* Note: we must check them all anyway, as some objects may
 446          * want to do something when signaled, even if others are not */
 447         for (i = 0, entry = wait->queues; i < wait->count; i++, entry++)
 448             not_ok |= !entry->obj->ops->signaled( entry->obj, thread );
 449         if (not_ok) goto other_checks;
 450         /* Wait satisfied: tell it to all objects */
 451         signaled = 0;
 452         for (i = 0, entry = wait->queues; i < wait->count; i++, entry++)
 453             if (entry->obj->ops->satisfied( entry->obj, thread ))
 454                 signaled = STATUS_ABANDONED_WAIT_0;
 455         return signaled;
 456     }
 457     else
 458     {
 459         for (i = 0, entry = wait->queues; i < wait->count; i++, entry++)
 460         {
 461             if (!entry->obj->ops->signaled( entry->obj, thread )) continue;
 462             /* Wait satisfied: tell it to the object */
 463             signaled = i;
 464             if (entry->obj->ops->satisfied( entry->obj, thread ))
 465                 signaled = i + STATUS_ABANDONED_WAIT_0;
 466             return signaled;
 467         }
 468     }
 469
 470  other_checks:
 471     if ((wait->flags & SELECT_INTERRUPTIBLE) && thread->system_apc.head) return STATUS_USER_APC;
 472     if ((wait->flags & SELECT_ALERTABLE) && thread->user_apc.head) return STATUS_USER_APC;
 473     if (wait->flags & SELECT_TIMEOUT)
 474     {
 475         struct timeval now;
 476         gettimeofday( &now, NULL );
 477         if (!time_before( &now, &wait->timeout )) return STATUS_TIMEOUT;
 478     }
 479     return -1;
 480 }
 481
 482 /* attempt to wake up a thread */
 483 /* return 1 if OK, 0 if the wait condition is still not satisfied */
 484 static int wake_thread( struct thread *thread )
 485 {
 486     int signaled;
 487     if ((signaled = check_wait( thread )) == -1) return 0;
 488
 489     if (debug_level) fprintf( stderr, "%08x: *wakeup* object=%d\n",
 490                               (unsigned int)thread, signaled );
 491     end_wait( thread );
 492     send_thread_wakeup( thread, signaled );
 493     return 1;
 494 }
 495
 496 /* thread wait timeout */
 497 static void thread_timeout( void *ptr )
 498 {
 499     struct thread *thread = ptr;
 500
 501     if (debug_level) fprintf( stderr, "%08x: *timeout*\n", (unsigned int)thread );
 502
 503     assert( thread->wait );
 504     thread->wait->user = NULL;
 505     end_wait( thread );
 506     send_thread_wakeup( thread, STATUS_TIMEOUT );
 507 }
 508
 509 /* select on a list of handles */
 510 static void select_on( int count, handle_t *handles, int flags, int sec, int usec )
 511 {
 512     int ret, i;
 513     struct object *objects[MAXIMUM_WAIT_OBJECTS];
 514
 515     assert( !current->wait );
 516
 517     if ((count < 0) || (count > MAXIMUM_WAIT_OBJECTS))
 518     {
 519         set_error( STATUS_INVALID_PARAMETER );
 520         return;
 521     }
 522     for (i = 0; i < count; i++)
 523     {
 524         if (!(objects[i] = get_handle_obj( current->process, handles[i], SYNCHRONIZE, NULL )))
 525             break;
 526     }
 527
 528     if (i < count) goto done;
 529     if (!wait_on( count, objects, flags, sec, usec )) goto done;
 530
 531     if ((ret = check_wait( current )) != -1)
 532     {
 533         /* condition is already satisfied */
 534         end_wait( current );
 535         set_error( ret );
 536         goto done;
 537     }
 538
 539     /* now we need to wait */
 540     if (flags & SELECT_TIMEOUT)
 541     {
 542         if (!(current->wait->user = add_timeout_user( &current->wait->timeout,
 543                                                       thread_timeout, current )))
 544         {
 545             end_wait( current );
 546             goto done;
 547         }
 548     }
 549     set_error( STATUS_PENDING );
 550
 551 done:
 552     while (--i >= 0) release_object( objects[i] );
 553 }
 554
 555 /* attempt to wake threads sleeping on the object wait queue */
 556 void wake_up( struct object *obj, int max )
 557 {
 558     struct wait_queue_entry *entry = obj->head;
 559
 560     while (entry)
 561     {
 562         struct thread *thread = entry->thread;
 563         entry = entry->next;
 564         if (wake_thread( thread ))
 565         {
 566             if (max && !--max) break;
 567         }
 568     }
 569 }
 570
 571 /* queue an async procedure call */
 572 int thread_queue_apc( struct thread *thread, struct object *owner, void *func,
 573                       enum apc_type type, int system, int nb_args, ... )
 574 {
 575     struct thread_apc *apc;
 576     struct apc_queue *queue = system ? &thread->system_apc : &thread->user_apc;
 577
 578     /* cancel a possible previous APC with the same owner */
 579     if (owner) thread_cancel_apc( thread, owner, system );
 580
 581     if (!(apc = mem_alloc( sizeof(*apc) + (nb_args-1)*sizeof(apc->args[0]) ))) return 0;
 582     apc->prev    = queue->tail;
 583     apc->next    = NULL;
 584     apc->owner   = owner;
 585     apc->func    = func;
 586     apc->type    = type;
 587     apc->nb_args = nb_args;
 588     if (nb_args)
 589     {
 590         int i;
 591         va_list args;
 592         va_start( args, nb_args );
 593         for (i = 0; i < nb_args; i++) apc->args[i] = va_arg( args, void * );
 594         va_end( args );
 595     }
 596     queue->tail = apc;
 597     if (!apc->prev)  /* first one */
 598     {
 599         queue->head = apc;
 600         if (thread->wait) wake_thread( thread );
 601     }
 602     return 1;
 603 }
 604
 605 /* cancel the async procedure call owned by a specific object */
 606 void thread_cancel_apc( struct thread *thread, struct object *owner, int system )
 607 {
 608     struct thread_apc *apc;
 609     struct apc_queue *queue = system ? &thread->system_apc : &thread->user_apc;
 610     for (apc = queue->head; apc; apc = apc->next)
 611     {
 612         if (apc->owner != owner) continue;
 613         if (apc->next) apc->next->prev = apc->prev;
 614         else queue->tail = apc->prev;
 615         if (apc->prev) apc->prev->next = apc->next;
 616         else queue->head = apc->next;
 617         free( apc );
 618         return;
 619     }
 620 }
 621
 622 /* remove the head apc from the queue; the returned pointer must be freed by the caller */
 623 static struct thread_apc *thread_dequeue_apc( struct thread *thread, int system_only )
 624 {
 625     struct thread_apc *apc;
 626     struct apc_queue *queue = &thread->system_apc;
 627
 628     if (!queue->head && !system_only) queue = &thread->user_apc;
 629     if ((apc = queue->head))
 630     {
 631         if (apc->next) apc->next->prev = NULL;
 632         else queue->tail = NULL;
 633         queue->head = apc->next;
 634     }
 635     return apc;
 636 }
 637
 638 /* add an fd to the inflight list */
 639 /* return list index, or -1 on error */
 640 int thread_add_inflight_fd( struct thread *thread, int client, int server )
 641 {
 642     int i;
 643
 644     if (server == -1) return -1;
 645     if (client == -1)
 646     {
 647         close( server );
 648         return -1;
 649     }
 650
 651     /* first check if we already have an entry for this fd */
 652     for (i = 0; i < MAX_INFLIGHT_FDS; i++)
 653         if (thread->inflight[i].client == client)
 654         {
 655             close( thread->inflight[i].server );
 656             thread->inflight[i].server = server;
 657             return i;
 658         }
 659
 660     /* now find a free spot to store it */
 661     for (i = 0; i < MAX_INFLIGHT_FDS; i++)
 662         if (thread->inflight[i].client == -1)
 663         {
 664             thread->inflight[i].client = client;
 665             thread->inflight[i].server = server;
 666             return i;
 667         }
 668     return -1;
 669 }
 670
 671 /* get an inflight fd and purge it from the list */
 672 /* the fd must be closed when no longer used */
 673 int thread_get_inflight_fd( struct thread *thread, int client )
 674 {
 675     int i, ret;
 676
 677     if (client == -1) return -1;
 678
 679     do
 680     {
 681         for (i = 0; i < MAX_INFLIGHT_FDS; i++)
 682         {
 683             if (thread->inflight[i].client == client)
 684             {
 685                 ret = thread->inflight[i].server;
 686                 thread->inflight[i].server = thread->inflight[i].client = -1;
 687                 return ret;
 688             }
 689         }
 690     } while (!receive_fd( thread->process ));  /* in case it is still in the socket buffer */
 691     return -1;
 692 }
 693
 694 /* retrieve an LDT selector entry */
 695 static void get_selector_entry( struct thread *thread, int entry,
 696                                 unsigned int *base, unsigned int *limit,
 697                                 unsigned char *flags )
 698 {
 699     if (!thread->process->ldt_copy)
 700     {
 701         set_error( STATUS_ACCESS_DENIED );
 702         return;
 703     }
 704     if (entry >= 8192)
 705     {
 706         set_error( STATUS_INVALID_PARAMETER );  /* FIXME */
 707         return;
 708     }
 709     if (suspend_for_ptrace( thread ))
 710     {
 711         unsigned char flags_buf[4];
 712         int *addr = (int *)thread->process->ldt_copy + entry;
 713         if (read_thread_int( thread, addr, base ) == -1) goto done;
 714         if (read_thread_int( thread, addr + 8192, limit ) == -1) goto done;
 715         addr = (int *)thread->process->ldt_copy + 2*8192 + (entry >> 2);
 716         if (read_thread_int( thread, addr, (int *)flags_buf ) == -1) goto done;
 717         *flags = flags_buf[entry & 3];
 718     done:
 719         resume_thread( thread );
 720     }
 721 }
 722
 723 /* kill a thread on the spot */
 724 void kill_thread( struct thread *thread, int violent_death )
 725 {
 726     if (thread->state == TERMINATED) return;  /* already killed */
 727     thread->state = TERMINATED;
 728     if (current == thread) current = NULL;
 729     if (debug_level)
 730         fprintf( stderr,"%08x: *killed* exit_code=%d\n",
 731                  (unsigned int)thread, thread->exit_code );
 732     if (thread->wait)
 733     {
 734         end_wait( thread );
 735         /* if it is waiting on the socket, we don't need to send a SIGTERM */
 736         violent_death = 0;
 737     }
 738     debug_exit_thread( thread );
 739     abandon_mutexes( thread );
 740     remove_process_thread( thread->process, thread );
 741     wake_up( &thread->obj, 0 );
 742     detach_thread( thread, violent_death ? SIGTERM : 0 );
 743     remove_select_user( &thread->obj );
 744     cleanup_thread( thread );
 745     release_object( thread );
 746 }
 747
 748 /* take a snapshot of currently running threads */
 749 struct thread_snapshot *thread_snap( int *count )
 750 {
 751     struct thread_snapshot *snapshot, *ptr;
 752     struct thread *thread;
 753     int total = 0;
 754
 755     for (thread = first_thread; thread; thread = thread->next)
 756         if (thread->state != TERMINATED) total++;
 757     if (!total || !(snapshot = mem_alloc( sizeof(*snapshot) * total ))) return NULL;
 758     ptr = snapshot;
 759     for (thread = first_thread; thread; thread = thread->next)
 760     {
 761         if (thread->state == TERMINATED) continue;
 762         ptr->thread   = thread;
 763         ptr->count    = thread->obj.refcount;
 764         ptr->priority = thread->priority;
 765         grab_object( thread );
 766         ptr++;
 767     }
 768     *count = total;
 769     return snapshot;
 770 }
 771
 772 /* signal that we are finished booting on the client side */
 773 DECL_HANDLER(boot_done)
 774 {
 775     debug_level = max( debug_level, req->debug_level );
 776     /* Make sure last_req is initialized */
 777     current->last_req = REQ_boot_done;
 778     if (current == booting_thread)
 779     {
 780         booting_thread = (struct thread *)~0UL;  /* make sure it doesn't match other threads */
 781         lock_master_socket(0);  /* allow other clients now */
 782     }
 783 }
 784
 785 /* create a new thread */
 786 DECL_HANDLER(new_thread)
 787 {
 788     struct thread *thread;
 789     int sock[2];
 790
 791     if (socketpair( AF_UNIX, SOCK_STREAM, 0, sock ) != -1)
 792     {
 793         if ((thread = create_thread( sock[0], current->process )))
 794         {
 795             if (req->suspend) thread->suspend++;
 796             req->tid = thread;
 797             if ((req->handle = alloc_handle( current->process, thread,
 798                                              THREAD_ALL_ACCESS, req->inherit )))
 799             {
 800                 send_client_fd( current, sock[1], req->handle );
 801                 close( sock[1] );
 802                 /* thread object will be released when the thread gets killed */
 803                 return;
 804             }
 805             kill_thread( thread, 1 );
 806         }
 807         close( sock[1] );
 808     }
 809     else file_set_error();
 810 }
 811
 812 /* retrieve the thread buffer file descriptor */
 813 DECL_HANDLER(get_thread_buffer)
 814 {
 815     fatal_protocol_error( current, "get_thread_buffer: should never get called directly\n" );
 816 }
 817
 818 /* initialize a new thread */
 819 DECL_HANDLER(init_thread)
 820 {
 821     if (current->unix_pid)
 822     {
 823         fatal_protocol_error( current, "init_thread: already running\n" );
 824         return;
 825     }
 826     current->unix_pid = req->unix_pid;
 827     current->teb      = req->teb;
 828     if (current->suspend + current->process->suspend > 0) stop_thread( current );
 829     if (current->process->running_threads > 1)
 830         generate_debug_event( current, CREATE_THREAD_DEBUG_EVENT, req->entry );
 831 }
 832
 833 /* terminate a thread */
 834 DECL_HANDLER(terminate_thread)
 835 {
 836     struct thread *thread;
 837
 838     req->self = 0;
 839     req->last = 0;
 840     if ((thread = get_thread_from_handle( req->handle, THREAD_TERMINATE )))
 841     {
 842         thread->exit_code = req->exit_code;
 843         if (thread != current) kill_thread( thread, 1 );
 844         else
 845         {
 846             req->self = 1;
 847             req->last = (thread->process->running_threads == 1);
 848         }
 849         release_object( thread );
 850     }
 851 }
 852
 853 /* fetch information about a thread */
 854 DECL_HANDLER(get_thread_info)
 855 {
 856     struct thread *thread;
 857     handle_t handle = req->handle;
 858
 859     if (!handle) thread = get_thread_from_id( req->tid_in );
 860     else thread = get_thread_from_handle( req->handle, THREAD_QUERY_INFORMATION );
 861
 862     if (thread)
 863     {
 864         req->tid       = get_thread_id( thread );
 865         req->teb       = thread->teb;
 866         req->exit_code = (thread->state == TERMINATED) ? thread->exit_code : STILL_ACTIVE;
 867         req->priority  = thread->priority;
 868         release_object( thread );
 869     }
 870 }
 871
 872 /* set information about a thread */
 873 DECL_HANDLER(set_thread_info)
 874 {
 875     struct thread *thread;
 876
 877     if ((thread = get_thread_from_handle( req->handle, THREAD_SET_INFORMATION )))
 878     {
 879         set_thread_info( thread, req );
 880         release_object( thread );
 881     }
 882 }
 883
 884 /* suspend a thread */
 885 DECL_HANDLER(suspend_thread)
 886 {
 887     struct thread *thread;
 888
 889     if ((thread = get_thread_from_handle( req->handle, THREAD_SUSPEND_RESUME )))
 890     {
 891         req->count = suspend_thread( thread, 1 );
 892         release_object( thread );
 893     }
 894 }
 895
 896 /* resume a thread */
 897 DECL_HANDLER(resume_thread)
 898 {
 899     struct thread *thread;
 900
 901     if ((thread = get_thread_from_handle( req->handle, THREAD_SUSPEND_RESUME )))
 902     {
 903         req->count = resume_thread( thread );
 904         release_object( thread );
 905     }
 906 }
 907
 908 /* select on a handle list */
 909 DECL_HANDLER(select)
 910 {
 911     int count = get_req_data_size(req) / sizeof(int);
 912     select_on( count, get_req_data(req), req->flags, req->sec, req->usec );
 913 }
 914
 915 /* queue an APC for a thread */
 916 DECL_HANDLER(queue_apc)
 917 {
 918     struct thread *thread;
 919     if ((thread = get_thread_from_handle( req->handle, THREAD_SET_CONTEXT )))
 920     {
 921         thread_queue_apc( thread, NULL, req->func, APC_USER, !req->user, 1, req->param );
 922         release_object( thread );
 923     }
 924 }
 925
 926 /* get next APC to call */
 927 DECL_HANDLER(get_apc)
 928 {
 929     struct thread_apc *apc;
 930     size_t size;
 931
 932     for (;;)
 933     {
 934         if (!(apc = thread_dequeue_apc( current, !req->alertable )))
 935         {
 936             /* no more APCs */
 937             req->func    = NULL;
 938             req->type    = APC_NONE;
 939             set_req_data_size( req, 0 );
 940             return;
 941         }
 942         /* Optimization: ignore APCs that have a NULL func; they are only used
 943          * to wake up a thread, but since we got here the thread woke up already.
 944          */
 945         if (apc->func) break;
 946         free( apc );
 947     }
 948     size = apc->nb_args * sizeof(apc->args[0]);
 949     if (size > get_req_data_size(req)) size = get_req_data_size(req);
 950     req->func = apc->func;
 951     req->type = apc->type;
 952     memcpy( get_req_data(req), apc->args, size );
 953     set_req_data_size( req, size );
 954     free( apc );
 955 }
 956
 957 /* fetch a selector entry for a thread */
 958 DECL_HANDLER(get_selector_entry)
 959 {
 960     struct thread *thread;
 961     if ((thread = get_thread_from_handle( req->handle, THREAD_QUERY_INFORMATION )))
 962     {
 963         get_selector_entry( thread, req->entry, &req->base, &req->limit, &req->flags );
 964         release_object( thread );
 965     }
 966 }