server/debugger.c

   1 /*
   2  * Server-side debugger functions
   3  *
   4  * Copyright (C) 1999 Alexandre Julliard
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, write to the Free Software
  18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19  */
  20
  21 #include "config.h"
  22 #include "wine/port.h"
  23
  24 #include <assert.h>
  25 #include <signal.h>
  26 #include <string.h>
  27 #include <stdarg.h>
  28 #include <stdio.h>
  29
  30 #include "windef.h"
  31 #include "winbase.h"
  32
  33 #include "handle.h"
  34 #include "process.h"
  35 #include "thread.h"
  36 #include "request.h"
  37 #include "console.h"
  38
  39 enum debug_event_state { EVENT_QUEUED, EVENT_SENT, EVENT_CONTINUED };
  40
  41 /* debug event */
  42 struct debug_event
  43 {
  44     struct object          obj;       /* object header */
  45     struct list            entry;     /* entry in event queue */
  46     struct thread         *sender;    /* thread which sent this event */
  47     struct thread         *debugger;  /* debugger thread receiving the event */
  48     enum debug_event_state state;     /* event state */
  49     int                    status;    /* continuation status */
  50     debug_event_t          data;      /* event data */
  51     CONTEXT                context;   /* register context */
  52 };
  53
  54 /* debug context */
  55 struct debug_ctx
  56 {
  57     struct object        obj;         /* object header */
  58     struct list          event_queue; /* pending events queue */
  59     int                  kill_on_exit;/* kill debuggees on debugger exit ? */
  60 };
  61
  62
  63 static void debug_event_dump( struct object *obj, int verbose );
  64 static int debug_event_signaled( struct object *obj, struct thread *thread );
  65 static void debug_event_destroy( struct object *obj );
  66
  67 static const struct object_ops debug_event_ops =
  68 {
  69     sizeof(struct debug_event),    /* size */
  70     debug_event_dump,              /* dump */
  71     add_queue,                     /* add_queue */
  72     remove_queue,                  /* remove_queue */
  73     debug_event_signaled,          /* signaled */
  74     no_satisfied,                  /* satisfied */
  75     no_signal,                     /* signal */
  76     no_get_fd,                     /* get_fd */
  77     no_close_handle,               /* close_handle */
  78     debug_event_destroy            /* destroy */
  79 };
  80
  81 static void debug_ctx_dump( struct object *obj, int verbose );
  82 static int debug_ctx_signaled( struct object *obj, struct thread *thread );
  83 static void debug_ctx_destroy( struct object *obj );
  84
  85 static const struct object_ops debug_ctx_ops =
  86 {
  87     sizeof(struct debug_ctx),      /* size */
  88     debug_ctx_dump,                /* dump */
  89     add_queue,                     /* add_queue */
  90     remove_queue,                  /* remove_queue */
  91     debug_ctx_signaled,            /* signaled */
  92     no_satisfied,                  /* satisfied */
  93     no_signal,                     /* signal */
  94     no_get_fd,                     /* get_fd */
  95     no_close_handle,               /* close_handle */
  96     debug_ctx_destroy              /* destroy */
  97 };
  98
  99
 100 /* routines to build an event according to its type */
 101
 102 static int fill_exception_event( struct debug_event *event, void *arg )
 103 {
 104     memcpy( &event->data.info.exception, arg, sizeof(event->data.info.exception) );
 105     return 1;
 106 }
 107
 108 static int fill_create_thread_event( struct debug_event *event, void *arg )
 109 {
 110     struct process *debugger = event->debugger->process;
 111     struct thread *thread = event->sender;
 112     obj_handle_t handle;
 113
 114     /* documented: THREAD_GET_CONTEXT | THREAD_SET_CONTEXT | THREAD_SUSPEND_RESUME */
 115     if (!(handle = alloc_handle( debugger, thread, THREAD_ALL_ACCESS, FALSE ))) return 0;
 116     event->data.info.create_thread.handle = handle;
 117     event->data.info.create_thread.teb    = thread->teb;
 118     event->data.info.create_thread.start  = arg;
 119     return 1;
 120 }
 121
 122 static int fill_create_process_event( struct debug_event *event, void *arg )
 123 {
 124     struct process *debugger = event->debugger->process;
 125     struct thread *thread = event->sender;
 126     struct process *process = thread->process;
 127     obj_handle_t handle;
 128
 129     /* documented: PROCESS_VM_READ | PROCESS_VM_WRITE */
 130     if (!(handle = alloc_handle( debugger, process, PROCESS_ALL_ACCESS, FALSE ))) return 0;
 131     event->data.info.create_process.process = handle;
 132
 133     /* documented: THREAD_GET_CONTEXT | THREAD_SET_CONTEXT | THREAD_SUSPEND_RESUME */
 134     if (!(handle = alloc_handle( debugger, thread, THREAD_ALL_ACCESS, FALSE )))
 135     {
 136         close_handle( debugger, event->data.info.create_process.process, NULL );
 137         return 0;
 138     }
 139     event->data.info.create_process.thread = handle;
 140
 141     handle = 0;
 142     if (process->exe.file &&
 143         /* the doc says write access too, but this doesn't seem a good idea */
 144         !(handle = alloc_handle( debugger, process->exe.file, GENERIC_READ, FALSE )))
 145     {
 146         close_handle( debugger, event->data.info.create_process.process, NULL );
 147         close_handle( debugger, event->data.info.create_process.thread, NULL );
 148         return 0;
 149     }
 150     event->data.info.create_process.file       = handle;
 151     event->data.info.create_process.teb        = thread->teb;
 152     event->data.info.create_process.base       = process->exe.base;
 153     event->data.info.create_process.start      = arg;
 154     event->data.info.create_process.dbg_offset = process->exe.dbg_offset;
 155     event->data.info.create_process.dbg_size   = process->exe.dbg_size;
 156     event->data.info.create_process.name       = process->exe.name;
 157     event->data.info.create_process.unicode    = 1;
 158     return 1;
 159 }
 160
 161 static int fill_exit_thread_event( struct debug_event *event, void *arg )
 162 {
 163     struct thread *thread = arg;
 164     event->data.info.exit.exit_code = thread->exit_code;
 165     return 1;
 166 }
 167
 168 static int fill_exit_process_event( struct debug_event *event, void *arg )
 169 {
 170     struct process *process = arg;
 171     event->data.info.exit.exit_code = process->exit_code;
 172     return 1;
 173 }
 174
 175 static int fill_load_dll_event( struct debug_event *event, void *arg )
 176 {
 177     struct process *debugger = event->debugger->process;
 178     struct process_dll *dll = arg;
 179     obj_handle_t handle = 0;
 180
 181     if (dll->file && !(handle = alloc_handle( debugger, dll->file, GENERIC_READ, FALSE )))
 182         return 0;
 183     event->data.info.load_dll.handle     = handle;
 184     event->data.info.load_dll.base       = dll->base;
 185     event->data.info.load_dll.dbg_offset = dll->dbg_offset;
 186     event->data.info.load_dll.dbg_size   = dll->dbg_size;
 187     event->data.info.load_dll.name       = dll->name;
 188     event->data.info.load_dll.unicode    = 1;
 189     return 1;
 190 }
 191
 192 static int fill_unload_dll_event( struct debug_event *event, void *arg )
 193 {
 194     event->data.info.unload_dll.base = arg;
 195     return 1;
 196 }
 197
 198 static int fill_output_debug_string_event( struct debug_event *event, void *arg )
 199 {
 200     struct debug_event_output_string *data = arg;
 201     event->data.info.output_string = *data;
 202     return 1;
 203 }
 204
 205 typedef int (*fill_event_func)( struct debug_event *event, void *arg );
 206
 207 #define NB_DEBUG_EVENTS OUTPUT_DEBUG_STRING_EVENT  /* RIP_EVENT not supported */
 208
 209 static const fill_event_func fill_debug_event[NB_DEBUG_EVENTS] =
 210 {
 211     fill_exception_event,            /* EXCEPTION_DEBUG_EVENT */
 212     fill_create_thread_event,        /* CREATE_THREAD_DEBUG_EVENT */
 213     fill_create_process_event,       /* CREATE_PROCESS_DEBUG_EVENT */
 214     fill_exit_thread_event,          /* EXIT_THREAD_DEBUG_EVENT */
 215     fill_exit_process_event,         /* EXIT_PROCESS_DEBUG_EVENT */
 216     fill_load_dll_event,             /* LOAD_DLL_DEBUG_EVENT */
 217     fill_unload_dll_event,           /* UNLOAD_DLL_DEBUG_EVENT */
 218     fill_output_debug_string_event   /* OUTPUT_DEBUG_STRING_EVENT */
 219 };
 220
 221
 222 /* unlink the first event from the queue */
 223 static void unlink_event( struct debug_ctx *debug_ctx, struct debug_event *event )
 224 {
 225     list_remove( &event->entry );
 226     if (event->sender->debug_event == event) event->sender->debug_event = NULL;
 227     release_object( event );
 228 }
 229
 230 /* link an event at the end of the queue */
 231 static void link_event( struct debug_event *event )
 232 {
 233     struct debug_ctx *debug_ctx = event->debugger->debug_ctx;
 234
 235     assert( debug_ctx );
 236     grab_object( event );
 237     list_add_tail( &debug_ctx->event_queue, &event->entry );
 238     if (!event->sender->debug_event) wake_up( &debug_ctx->obj, 0 );
 239 }
 240
 241 /* find the next event that we can send to the debugger */
 242 static struct debug_event *find_event_to_send( struct debug_ctx *debug_ctx )
 243 {
 244     struct debug_event *event;
 245
 246     LIST_FOR_EACH_ENTRY( event, &debug_ctx->event_queue, struct debug_event, entry )
 247     {
 248         if (event->state == EVENT_SENT) continue;  /* already sent */
 249         if (event->sender->debug_event) continue;  /* thread busy with another one */
 250         return event;
 251     }
 252     return NULL;
 253 }
 254
 255 static void debug_event_dump( struct object *obj, int verbose )
 256 {
 257     struct debug_event *debug_event = (struct debug_event *)obj;
 258     assert( obj->ops == &debug_event_ops );
 259     fprintf( stderr, "Debug event sender=%p code=%d state=%d\n",
 260              debug_event->sender, debug_event->data.code, debug_event->state );
 261 }
 262
 263 static int debug_event_signaled( struct object *obj, struct thread *thread )
 264 {
 265     struct debug_event *debug_event = (struct debug_event *)obj;
 266     assert( obj->ops == &debug_event_ops );
 267     return debug_event->state == EVENT_CONTINUED;
 268 }
 269
 270 static void debug_event_destroy( struct object *obj )
 271 {
 272     struct debug_event *event = (struct debug_event *)obj;
 273     assert( obj->ops == &debug_event_ops );
 274
 275     /* If the event has been sent already, the handles are now under the */
 276     /* responsibility of the debugger process, so we don't touch them    */
 277     if (event->state == EVENT_QUEUED)
 278     {
 279         struct process *debugger = event->debugger->process;
 280         switch(event->data.code)
 281         {
 282         case CREATE_THREAD_DEBUG_EVENT:
 283             close_handle( debugger, event->data.info.create_thread.handle, NULL );
 284             break;
 285         case CREATE_PROCESS_DEBUG_EVENT:
 286             if (event->data.info.create_process.file)
 287                 close_handle( debugger, event->data.info.create_process.file, NULL );
 288             close_handle( debugger, event->data.info.create_process.thread, NULL );
 289             close_handle( debugger, event->data.info.create_process.process, NULL );
 290             break;
 291         case LOAD_DLL_DEBUG_EVENT:
 292             if (event->data.info.load_dll.handle)
 293                 close_handle( debugger, event->data.info.load_dll.handle, NULL );
 294             break;
 295         }
 296     }
 297     if (event->sender->context == &event->context) event->sender->context = NULL;
 298     release_object( event->sender );
 299     release_object( event->debugger );
 300 }
 301
 302 static void debug_ctx_dump( struct object *obj, int verbose )
 303 {
 304     struct debug_ctx *debug_ctx = (struct debug_ctx *)obj;
 305     assert( obj->ops == &debug_ctx_ops );
 306     fprintf( stderr, "Debug context head=%p tail=%p\n",
 307              debug_ctx->event_queue.next, debug_ctx->event_queue.prev );
 308 }
 309
 310 static int debug_ctx_signaled( struct object *obj, struct thread *thread )
 311 {
 312     struct debug_ctx *debug_ctx = (struct debug_ctx *)obj;
 313     assert( obj->ops == &debug_ctx_ops );
 314     return find_event_to_send( debug_ctx ) != NULL;
 315 }
 316
 317 static void debug_ctx_destroy( struct object *obj )
 318 {
 319     struct list *ptr;
 320     struct debug_ctx *debug_ctx = (struct debug_ctx *)obj;
 321     assert( obj->ops == &debug_ctx_ops );
 322
 323     /* free all pending events */
 324     while ((ptr = list_head( &debug_ctx->event_queue )))
 325         unlink_event( debug_ctx, LIST_ENTRY( ptr, struct debug_event, entry ));
 326 }
 327
 328 /* continue a debug event */
 329 static int continue_debug_event( struct process *process, struct thread *thread, int status )
 330 {
 331     struct debug_ctx *debug_ctx = current->debug_ctx;
 332
 333     if (debug_ctx && process->debugger == current && thread->process == process)
 334     {
 335         struct debug_event *event;
 336
 337         /* find the event in the queue */
 338         LIST_FOR_EACH_ENTRY( event, &debug_ctx->event_queue, struct debug_event, entry )
 339         {
 340             if (event->state != EVENT_SENT) continue;
 341             if (event->sender == thread)
 342             {
 343                 assert( event->sender->debug_event == event );
 344
 345                 event->status = status;
 346                 event->state  = EVENT_CONTINUED;
 347                 wake_up( &event->obj, 0 );
 348                 unlink_event( debug_ctx, event );
 349                 resume_process( process );
 350                 return 1;
 351             }
 352         }
 353     }
 354     /* not debugging this process, or no such event */
 355     set_error( STATUS_ACCESS_DENIED );  /* FIXME */
 356     return 0;
 357 }
 358
 359 /* alloc a debug event for a debugger */
 360 static struct debug_event *alloc_debug_event( struct thread *thread, int code,
 361                                               void *arg, const CONTEXT *context )
 362 {
 363     struct thread *debugger = thread->process->debugger;
 364     struct debug_event *event;
 365
 366     assert( code > 0 && code <= NB_DEBUG_EVENTS );
 367     /* cannot queue a debug event for myself */
 368     assert( debugger->process != thread->process );
 369
 370     /* build the event */
 371     if (!(event = alloc_object( &debug_event_ops ))) return NULL;
 372     event->state     = EVENT_QUEUED;
 373     event->sender    = (struct thread *)grab_object( thread );
 374     event->debugger  = (struct thread *)grab_object( debugger );
 375     event->data.code = code;
 376
 377     if (!fill_debug_event[code-1]( event, arg ))
 378     {
 379         event->data.code = -1;  /* make sure we don't attempt to close handles */
 380         release_object( event );
 381         return NULL;
 382     }
 383     if (context)
 384     {
 385         memcpy( &event->context, context, sizeof(event->context) );
 386         thread->context = &event->context;
 387     }
 388     return event;
 389 }
 390
 391 /* generate a debug event from inside the server and queue it */
 392 void generate_debug_event( struct thread *thread, int code, void *arg )
 393 {
 394     if (thread->process->debugger)
 395     {
 396         struct debug_event *event = alloc_debug_event( thread, code, arg, NULL );
 397         if (event)
 398         {
 399             link_event( event );
 400             suspend_process( thread->process );
 401             release_object( event );
 402         }
 403     }
 404 }
 405
 406 /* attach a process to a debugger thread and suspend it */
 407 static int debugger_attach( struct process *process, struct thread *debugger )
 408 {
 409     struct thread *thread;
 410
 411     if (process->debugger) goto error;  /* already being debugged */
 412     if (!is_process_init_done( process )) goto error;  /* still starting up */
 413     if (list_empty( &process->thread_list )) goto error;  /* no thread running in the process */
 414
 415     /* make sure we don't create a debugging loop */
 416     for (thread = debugger; thread; thread = thread->process->debugger)
 417         if (thread->process == process) goto error;
 418
 419     /* don't let a debugger debug its console... won't work */
 420     if (debugger->process->console && debugger->process->console->renderer->process == process)
 421         goto error;
 422
 423     suspend_process( process );
 424     if (!attach_process( process ) || !set_process_debugger( process, debugger ))
 425     {
 426         resume_process( process );
 427         return 0;
 428     }
 429     if (!set_process_debug_flag( process, 1 ))
 430     {
 431         process->debugger = NULL;
 432         resume_process( process );
 433         return 0;
 434     }
 435     return 1;
 436
 437  error:
 438     set_error( STATUS_ACCESS_DENIED );
 439     return 0;
 440 }
 441
 442
 443 /* detach a process from a debugger thread (and resume it ?) */
 444 int debugger_detach( struct process *process, struct thread *debugger )
 445 {
 446     struct debug_event *event;
 447     struct debug_ctx *debug_ctx;
 448
 449     if (!process->debugger || process->debugger != debugger)
 450         goto error;  /* not currently debugged, or debugged by another debugger */
 451     if (!debugger->debug_ctx ) goto error; /* should be a debugger */
 452     /* init should be done, otherwise wouldn't be attached */
 453     assert(is_process_init_done(process));
 454
 455     suspend_process( process );
 456     /* send continue indication for all events */
 457     debug_ctx = debugger->debug_ctx;
 458
 459     /* find the event in the queue
 460      * FIXME: could loop on process' threads and look the debug_event field */
 461     LIST_FOR_EACH_ENTRY( event, &debug_ctx->event_queue, struct debug_event, entry )
 462     {
 463         if (event->state != EVENT_QUEUED) continue;
 464
 465         if (event->sender->process == process)
 466         {
 467             assert( event->sender->debug_event == event );
 468             event->status = DBG_CONTINUE;
 469             event->state  = EVENT_CONTINUED;
 470             wake_up( &event->obj, 0 );
 471             unlink_event( debug_ctx, event );
 472             /* from queued debug event */
 473             resume_process( process );
 474             break;
 475         }
 476     }
 477
 478     /* remove relationships between process and its debugger */
 479     process->debugger = NULL;
 480     if (!set_process_debug_flag( process, 0 )) clear_error();  /* ignore error */
 481     detach_process( process );
 482
 483     /* from this function */
 484     resume_process( process );
 485     return 0;
 486
 487  error:
 488     set_error( STATUS_ACCESS_DENIED );
 489     return 0;
 490 }
 491
 492 /* generate all startup events of a given process */
 493 void generate_startup_debug_events( struct process *process, void *entry )
 494 {
 495     struct list *ptr;
 496     struct thread *thread, *first_thread = get_process_first_thread( process );
 497
 498     /* generate creation events */
 499     LIST_FOR_EACH_ENTRY( thread, &process->thread_list, struct thread, proc_entry )
 500     {
 501         if (thread == first_thread)
 502             generate_debug_event( thread, CREATE_PROCESS_DEBUG_EVENT, entry );
 503         else
 504             generate_debug_event( thread, CREATE_THREAD_DEBUG_EVENT, NULL );
 505     }
 506
 507     /* generate dll events (in loading order, i.e. reverse list order) */
 508     ptr = list_tail( &process->dlls );
 509     while (ptr)
 510     {
 511         struct process_dll *dll = LIST_ENTRY( ptr, struct process_dll, entry );
 512         generate_debug_event( first_thread, LOAD_DLL_DEBUG_EVENT, dll );
 513         ptr = list_prev( &process->dlls, ptr );
 514     }
 515 }
 516
 517 /* set the debugger of a given process */
 518 int set_process_debugger( struct process *process, struct thread *debugger )
 519 {
 520     struct debug_ctx *debug_ctx;
 521
 522     assert( !process->debugger );
 523
 524     if (!debugger->debug_ctx)  /* need to allocate a context */
 525     {
 526         if (!(debug_ctx = alloc_object( &debug_ctx_ops ))) return 0;
 527         debug_ctx->kill_on_exit = 1;
 528         list_init( &debug_ctx->event_queue );
 529         debugger->debug_ctx = debug_ctx;
 530     }
 531     process->debugger = debugger;
 532     return 1;
 533 }
 534
 535 /* a thread is exiting */
 536 void debug_exit_thread( struct thread *thread )
 537 {
 538     if (thread->debug_ctx)  /* this thread is a debugger */
 539     {
 540         if (thread->debug_ctx->kill_on_exit)
 541         {
 542             /* kill all debugged processes */
 543             kill_debugged_processes( thread, thread->exit_code );
 544         }
 545         else
 546         {
 547             detach_debugged_processes( thread );
 548         }
 549         release_object( thread->debug_ctx );
 550         thread->debug_ctx = NULL;
 551     }
 552 }
 553
 554 /* Wait for a debug event */
 555 DECL_HANDLER(wait_debug_event)
 556 {
 557     struct debug_ctx *debug_ctx = current->debug_ctx;
 558     struct debug_event *event;
 559
 560     if (!debug_ctx)  /* current thread is not a debugger */
 561     {
 562         set_error( STATUS_INVALID_HANDLE );
 563         return;
 564     }
 565     reply->wait = 0;
 566     if ((event = find_event_to_send( debug_ctx )))
 567     {
 568         size_t size = get_reply_max_size();
 569         event->state = EVENT_SENT;
 570         event->sender->debug_event = event;
 571         reply->pid = get_process_id( event->sender->process );
 572         reply->tid = get_thread_id( event->sender );
 573         if (size > sizeof(debug_event_t)) size = sizeof(debug_event_t);
 574         set_reply_data( &event->data, size );
 575     }
 576     else  /* no event ready */
 577     {
 578         reply->pid  = 0;
 579         reply->tid  = 0;
 580         if (req->get_handle)
 581             reply->wait = alloc_handle( current->process, debug_ctx, SYNCHRONIZE, FALSE );
 582     }
 583 }
 584
 585 /* Continue a debug event */
 586 DECL_HANDLER(continue_debug_event)
 587 {
 588     struct process *process = get_process_from_id( req->pid );
 589     if (process)
 590     {
 591         struct thread *thread = get_thread_from_id( req->tid );
 592         if (thread)
 593         {
 594             continue_debug_event( process, thread, req->status );
 595             release_object( thread );
 596         }
 597         release_object( process );
 598     }
 599 }
 600
 601 /* Start debugging an existing process */
 602 DECL_HANDLER(debug_process)
 603 {
 604     struct process *process = get_process_from_id( req->pid );
 605     if (!process) return;
 606
 607     if (!req->attach)
 608     {
 609         debugger_detach( process, current );
 610     }
 611     else if (debugger_attach( process, current ))
 612     {
 613         struct debug_event_exception data;
 614         struct thread *thread = get_process_first_thread( process );
 615
 616         generate_startup_debug_events( process, NULL );
 617         resume_process( process );
 618
 619         data.record.ExceptionCode    = EXCEPTION_BREAKPOINT;
 620         data.record.ExceptionFlags   = EXCEPTION_CONTINUABLE;
 621         data.record.ExceptionRecord  = NULL;
 622         data.record.ExceptionAddress = get_thread_ip( thread );
 623         data.record.NumberParameters = 0;
 624         data.first = 1;
 625         generate_debug_event( thread, EXCEPTION_DEBUG_EVENT, &data );
 626     }
 627     release_object( process );
 628 }
 629
 630 /* queue an exception event */
 631 DECL_HANDLER(queue_exception_event)
 632 {
 633     reply->handle = 0;
 634     if (current->process->debugger)
 635     {
 636         struct debug_event_exception data;
 637         struct debug_event *event;
 638         const CONTEXT *context = get_req_data();
 639         const EXCEPTION_RECORD *rec = (const EXCEPTION_RECORD *)(context + 1);
 640
 641         if (get_req_data_size() < sizeof(*rec) + sizeof(*context))
 642         {
 643             set_error( STATUS_INVALID_PARAMETER );
 644             return;
 645         }
 646         data.record = *rec;
 647         data.first  = req->first;
 648         if ((event = alloc_debug_event( current, EXCEPTION_DEBUG_EVENT, &data, context )))
 649         {
 650             if ((reply->handle = alloc_handle( current->process, event, SYNCHRONIZE, FALSE )))
 651             {
 652                 link_event( event );
 653                 suspend_process( current->process );
 654             }
 655             release_object( event );
 656         }
 657     }
 658 }
 659
 660 /* retrieve the status of an exception event */
 661 DECL_HANDLER(get_exception_status)
 662 {
 663     struct debug_event *event;
 664
 665     reply->status = 0;
 666     if ((event = (struct debug_event *)get_handle_obj( current->process, req->handle,
 667                                                        0, &debug_event_ops )))
 668     {
 669         if (event->state == EVENT_CONTINUED)
 670         {
 671             reply->status = event->status;
 672             if (current->context == &event->context)
 673             {
 674                 size_t size = min( sizeof(CONTEXT), get_reply_max_size() );
 675                 set_reply_data( &event->context, size );
 676                 current->context = NULL;
 677             }
 678         }
 679         else set_error( STATUS_PENDING );
 680         release_object( event );
 681     }
 682 }
 683
 684 /* send an output string to the debugger */
 685 DECL_HANDLER(output_debug_string)
 686 {
 687     struct debug_event_output_string data;
 688
 689     data.string  = req->string;
 690     data.unicode = req->unicode;
 691     data.length  = req->length;
 692     generate_debug_event( current, OUTPUT_DEBUG_STRING_EVENT, &data );
 693 }
 694
 695 /* simulate a breakpoint in a process */
 696 DECL_HANDLER(debug_break)
 697 {
 698     struct process *process;
 699
 700     reply->self = 0;
 701     if (!(process = get_process_from_handle( req->handle, PROCESS_SET_INFORMATION /*FIXME*/ )))
 702         return;
 703     if (process != current->process)
 704     {
 705         /* find a suitable thread to signal */
 706         struct thread *thread;
 707         LIST_FOR_EACH_ENTRY( thread, &process->thread_list, struct thread, proc_entry )
 708         {
 709             if (send_thread_signal( thread, SIGTRAP )) goto done;
 710         }
 711         set_error( STATUS_ACCESS_DENIED );
 712     }
 713     else reply->self = 1;
 714
 715 done:
 716     release_object( process );
 717 }
 718
 719 /* set debugger kill on exit flag */
 720 DECL_HANDLER(set_debugger_kill_on_exit)
 721 {
 722     if (!current->debug_ctx)
 723     {
 724         set_error( STATUS_ACCESS_DENIED );
 725         return;
 726     }
 727     current->debug_ctx->kill_on_exit = req->kill_on_exit;
 728 }