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 debug_event    *next;      /* event queue */
  46     struct debug_event    *prev;
  47     struct thread         *sender;    /* thread which sent this event */
  48     struct thread         *debugger;  /* debugger thread receiving the event */
  49     enum debug_event_state state;     /* event state */
  50     int                    status;    /* continuation status */
  51     debug_event_t          data;      /* event data */
  52     CONTEXT                context;   /* register context */
  53 };
  54
  55 /* debug context */
  56 struct debug_ctx
  57 {
  58     struct object        obj;         /* object header */
  59     struct debug_event  *event_head;  /* head of pending events queue */
  60     struct debug_event  *event_tail;  /* tail of pending events queue */
  61     int                  kill_on_exit;/* kill debuggees on debugger exit ? */
  62 };
  63
  64
  65 static void debug_event_dump( struct object *obj, int verbose );
  66 static int debug_event_signaled( struct object *obj, struct thread *thread );
  67 static void debug_event_destroy( struct object *obj );
  68
  69 static const struct object_ops debug_event_ops =
  70 {
  71     sizeof(struct debug_event),    /* size */
  72     debug_event_dump,              /* dump */
  73     add_queue,                     /* add_queue */
  74     remove_queue,                  /* remove_queue */
  75     debug_event_signaled,          /* signaled */
  76     no_satisfied,                  /* satisfied */
  77     no_get_fd,                     /* get_fd */
  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_get_fd,                     /* get_fd */
  94     debug_ctx_destroy              /* destroy */
  95 };
  96
  97
  98 /* routines to build an event according to its type */
  99
 100 static int fill_exception_event( struct debug_event *event, void *arg )
 101 {
 102     memcpy( &event->data.info.exception, arg, sizeof(event->data.info.exception) );
 103     return 1;
 104 }
 105
 106 static int fill_create_thread_event( struct debug_event *event, void *arg )
 107 {
 108     struct process *debugger = event->debugger->process;
 109     struct thread *thread = event->sender;
 110     obj_handle_t handle;
 111
 112     /* documented: THREAD_GET_CONTEXT | THREAD_SET_CONTEXT | THREAD_SUSPEND_RESUME */
 113     if (!(handle = alloc_handle( debugger, thread, THREAD_ALL_ACCESS, FALSE ))) return 0;
 114     event->data.info.create_thread.handle = handle;
 115     event->data.info.create_thread.teb    = thread->teb;
 116     event->data.info.create_thread.start  = arg;
 117     return 1;
 118 }
 119
 120 static int fill_create_process_event( struct debug_event *event, void *arg )
 121 {
 122     struct process *debugger = event->debugger->process;
 123     struct thread *thread = event->sender;
 124     struct process *process = thread->process;
 125     obj_handle_t handle;
 126
 127     /* documented: PROCESS_VM_READ | PROCESS_VM_WRITE */
 128     if (!(handle = alloc_handle( debugger, process, PROCESS_ALL_ACCESS, FALSE ))) return 0;
 129     event->data.info.create_process.process = handle;
 130
 131     /* documented: THREAD_GET_CONTEXT | THREAD_SET_CONTEXT | THREAD_SUSPEND_RESUME */
 132     if (!(handle = alloc_handle( debugger, thread, THREAD_ALL_ACCESS, FALSE )))
 133     {
 134         close_handle( debugger, event->data.info.create_process.process, NULL );
 135         return 0;
 136     }
 137     event->data.info.create_process.thread = handle;
 138
 139     handle = 0;
 140     if (process->exe.file &&
 141         /* the doc says write access too, but this doesn't seem a good idea */
 142         !(handle = alloc_handle( debugger, process->exe.file, GENERIC_READ, FALSE )))
 143     {
 144         close_handle( debugger, event->data.info.create_process.process, NULL );
 145         close_handle( debugger, event->data.info.create_process.thread, NULL );
 146         return 0;
 147     }
 148     event->data.info.create_process.file       = handle;
 149     event->data.info.create_process.teb        = thread->teb;
 150     event->data.info.create_process.base       = process->exe.base;
 151     event->data.info.create_process.start      = arg;
 152     event->data.info.create_process.dbg_offset = process->exe.dbg_offset;
 153     event->data.info.create_process.dbg_size   = process->exe.dbg_size;
 154     event->data.info.create_process.name       = process->exe.name;
 155     event->data.info.create_process.unicode    = 1;
 156     return 1;
 157 }
 158
 159 static int fill_exit_thread_event( struct debug_event *event, void *arg )
 160 {
 161     struct thread *thread = arg;
 162     event->data.info.exit.exit_code = thread->exit_code;
 163     return 1;
 164 }
 165
 166 static int fill_exit_process_event( struct debug_event *event, void *arg )
 167 {
 168     struct process *process = arg;
 169     event->data.info.exit.exit_code = process->exit_code;
 170     return 1;
 171 }
 172
 173 static int fill_load_dll_event( struct debug_event *event, void *arg )
 174 {
 175     struct process *debugger = event->debugger->process;
 176     struct process_dll *dll = arg;
 177     obj_handle_t handle = 0;
 178
 179     if (dll->file && !(handle = alloc_handle( debugger, dll->file, GENERIC_READ, FALSE )))
 180         return 0;
 181     event->data.info.load_dll.handle     = handle;
 182     event->data.info.load_dll.base       = dll->base;
 183     event->data.info.load_dll.dbg_offset = dll->dbg_offset;
 184     event->data.info.load_dll.dbg_size   = dll->dbg_size;
 185     event->data.info.load_dll.name       = dll->name;
 186     event->data.info.load_dll.unicode    = 1;
 187     return 1;
 188 }
 189
 190 static int fill_unload_dll_event( struct debug_event *event, void *arg )
 191 {
 192     event->data.info.unload_dll.base = arg;
 193     return 1;
 194 }
 195
 196 static int fill_output_debug_string_event( struct debug_event *event, void *arg )
 197 {
 198     struct debug_event_output_string *data = arg;
 199     event->data.info.output_string = *data;
 200     return 1;
 201 }
 202
 203 typedef int (*fill_event_func)( struct debug_event *event, void *arg );
 204
 205 #define NB_DEBUG_EVENTS OUTPUT_DEBUG_STRING_EVENT  /* RIP_EVENT not supported */
 206
 207 static const fill_event_func fill_debug_event[NB_DEBUG_EVENTS] =
 208 {
 209     fill_exception_event,            /* EXCEPTION_DEBUG_EVENT */
 210     fill_create_thread_event,        /* CREATE_THREAD_DEBUG_EVENT */
 211     fill_create_process_event,       /* CREATE_PROCESS_DEBUG_EVENT */
 212     fill_exit_thread_event,          /* EXIT_THREAD_DEBUG_EVENT */
 213     fill_exit_process_event,         /* EXIT_PROCESS_DEBUG_EVENT */
 214     fill_load_dll_event,             /* LOAD_DLL_DEBUG_EVENT */
 215     fill_unload_dll_event,           /* UNLOAD_DLL_DEBUG_EVENT */
 216     fill_output_debug_string_event   /* OUTPUT_DEBUG_STRING_EVENT */
 217 };
 218
 219
 220 /* unlink the first event from the queue */
 221 static void unlink_event( struct debug_ctx *debug_ctx, struct debug_event *event )
 222 {
 223     if (event->prev) event->prev->next = event->next;
 224     else debug_ctx->event_head = event->next;
 225     if (event->next) event->next->prev = event->prev;
 226     else debug_ctx->event_tail = event->prev;
 227     event->next = event->prev = NULL;
 228     if (event->sender->debug_event == event) event->sender->debug_event = NULL;
 229     release_object( event );
 230 }
 231
 232 /* link an event at the end of the queue */
 233 static void link_event( struct debug_event *event )
 234 {
 235     struct debug_ctx *debug_ctx = event->debugger->debug_ctx;
 236
 237     assert( debug_ctx );
 238     grab_object( event );
 239     event->next = NULL;
 240     event->prev = debug_ctx->event_tail;
 241     debug_ctx->event_tail = event;
 242     if (event->prev) event->prev->next = event;
 243     else debug_ctx->event_head = event;
 244     if (!event->sender->debug_event) wake_up( &debug_ctx->obj, 0 );
 245 }
 246
 247 /* find the next event that we can send to the debugger */
 248 static struct debug_event *find_event_to_send( struct debug_ctx *debug_ctx )
 249 {
 250     struct debug_event *event;
 251     for (event = debug_ctx->event_head; event; event = event->next)
 252     {
 253         if (event->state == EVENT_SENT) continue;  /* already sent */
 254         if (event->sender->debug_event) continue;  /* thread busy with another one */
 255         break;
 256     }
 257     return event;
 258 }
 259
 260 static void debug_event_dump( struct object *obj, int verbose )
 261 {
 262     struct debug_event *debug_event = (struct debug_event *)obj;
 263     assert( obj->ops == &debug_event_ops );
 264     fprintf( stderr, "Debug event sender=%p code=%d state=%d\n",
 265              debug_event->sender, debug_event->data.code, debug_event->state );
 266 }
 267
 268 static int debug_event_signaled( struct object *obj, struct thread *thread )
 269 {
 270     struct debug_event *debug_event = (struct debug_event *)obj;
 271     assert( obj->ops == &debug_event_ops );
 272     return debug_event->state == EVENT_CONTINUED;
 273 }
 274
 275 static void debug_event_destroy( struct object *obj )
 276 {
 277     struct debug_event *event = (struct debug_event *)obj;
 278     assert( obj->ops == &debug_event_ops );
 279
 280     /* cannot still be in the queue */
 281     assert( !event->next );
 282     assert( !event->prev );
 283
 284     /* If the event has been sent already, the handles are now under the */
 285     /* responsibility of the debugger process, so we don't touch them    */
 286     if (event->state == EVENT_QUEUED)
 287     {
 288         struct process *debugger = event->debugger->process;
 289         switch(event->data.code)
 290         {
 291         case CREATE_THREAD_DEBUG_EVENT:
 292             close_handle( debugger, event->data.info.create_thread.handle, NULL );
 293             break;
 294         case CREATE_PROCESS_DEBUG_EVENT:
 295             if (event->data.info.create_process.file)
 296                 close_handle( debugger, event->data.info.create_process.file, NULL );
 297             close_handle( debugger, event->data.info.create_process.thread, NULL );
 298             close_handle( debugger, event->data.info.create_process.process, NULL );
 299             break;
 300         case LOAD_DLL_DEBUG_EVENT:
 301             if (event->data.info.load_dll.handle)
 302                 close_handle( debugger, event->data.info.load_dll.handle, NULL );
 303             break;
 304         }
 305     }
 306     if (event->sender->context == &event->context) event->sender->context = NULL;
 307     release_object( event->sender );
 308     release_object( event->debugger );
 309 }
 310
 311 static void debug_ctx_dump( struct object *obj, int verbose )
 312 {
 313     struct debug_ctx *debug_ctx = (struct debug_ctx *)obj;
 314     assert( obj->ops == &debug_ctx_ops );
 315     fprintf( stderr, "Debug context head=%p tail=%p\n",
 316              debug_ctx->event_head, debug_ctx->event_tail );
 317 }
 318
 319 static int debug_ctx_signaled( struct object *obj, struct thread *thread )
 320 {
 321     struct debug_ctx *debug_ctx = (struct debug_ctx *)obj;
 322     assert( obj->ops == &debug_ctx_ops );
 323     return find_event_to_send( debug_ctx ) != NULL;
 324 }
 325
 326 static void debug_ctx_destroy( struct object *obj )
 327 {
 328     struct debug_event *event;
 329     struct debug_ctx *debug_ctx = (struct debug_ctx *)obj;
 330     assert( obj->ops == &debug_ctx_ops );
 331
 332     /* free all pending events */
 333     while ((event = debug_ctx->event_head) != NULL) unlink_event( debug_ctx, event );
 334 }
 335
 336 /* continue a debug event */
 337 static int continue_debug_event( struct process *process, struct thread *thread, int status )
 338 {
 339     struct debug_event *event;
 340     struct debug_ctx *debug_ctx = current->debug_ctx;
 341
 342     if (!debug_ctx || process->debugger != current || thread->process != process) goto error;
 343
 344     /* find the event in the queue */
 345     for (event = debug_ctx->event_head; event; event = event->next)
 346     {
 347         if (event->state != EVENT_SENT) continue;
 348         if (event->sender == thread) break;
 349     }
 350     if (!event) goto error;
 351
 352     assert( event->sender->debug_event == event );
 353
 354     event->status = status;
 355     event->state  = EVENT_CONTINUED;
 356     wake_up( &event->obj, 0 );
 357
 358     unlink_event( debug_ctx, event );
 359     resume_process( process );
 360     return 1;
 361  error:
 362     /* not debugging this process, or no such event */
 363     set_error( STATUS_ACCESS_DENIED );  /* FIXME */
 364     return 0;
 365 }
 366
 367 /* alloc a debug event for a debugger */
 368 static struct debug_event *alloc_debug_event( struct thread *thread, int code,
 369                                               void *arg, const CONTEXT *context )
 370 {
 371     struct thread *debugger = thread->process->debugger;
 372     struct debug_event *event;
 373
 374     assert( code > 0 && code <= NB_DEBUG_EVENTS );
 375     /* cannot queue a debug event for myself */
 376     assert( debugger->process != thread->process );
 377
 378     /* build the event */
 379     if (!(event = alloc_object( &debug_event_ops ))) return NULL;
 380     event->next      = NULL;
 381     event->prev      = NULL;
 382     event->state     = EVENT_QUEUED;
 383     event->sender    = (struct thread *)grab_object( thread );
 384     event->debugger  = (struct thread *)grab_object( debugger );
 385     event->data.code = code;
 386
 387     if (!fill_debug_event[code-1]( event, arg ))
 388     {
 389         event->data.code = -1;  /* make sure we don't attempt to close handles */
 390         release_object( event );
 391         return NULL;
 392     }
 393     if (context)
 394     {
 395         memcpy( &event->context, context, sizeof(event->context) );
 396         thread->context = &event->context;
 397     }
 398     return event;
 399 }
 400
 401 /* generate a debug event from inside the server and queue it */
 402 void generate_debug_event( struct thread *thread, int code, void *arg )
 403 {
 404     if (thread->process->debugger)
 405     {
 406         struct debug_event *event = alloc_debug_event( thread, code, arg, NULL );
 407         if (event)
 408         {
 409             link_event( event );
 410             suspend_process( thread->process );
 411             release_object( event );
 412         }
 413     }
 414 }
 415
 416 /* attach a process to a debugger thread and suspend it */
 417 static int debugger_attach( struct process *process, struct thread *debugger )
 418 {
 419     struct thread *thread;
 420
 421     if (process->debugger) goto error;  /* already being debugged */
 422     if (!is_process_init_done( process )) goto error;  /* still starting up */
 423     if (!process->thread_list) goto error;  /* no thread running in the process */
 424
 425     /* make sure we don't create a debugging loop */
 426     for (thread = debugger; thread; thread = thread->process->debugger)
 427         if (thread->process == process) goto error;
 428
 429     /* don't let a debugger debug its console... won't work */
 430     if (debugger->process->console && debugger->process->console->renderer->process == process)
 431         goto error;
 432
 433     suspend_process( process );
 434     if (!attach_process( process ) || !set_process_debugger( process, debugger ))
 435     {
 436         resume_process( process );
 437         return 0;
 438     }
 439     if (!set_process_debug_flag( process, 1 ))
 440     {
 441         process->debugger = NULL;
 442         resume_process( process );
 443         return 0;
 444     }
 445     return 1;
 446
 447  error:
 448     set_error( STATUS_ACCESS_DENIED );
 449     return 0;
 450 }
 451
 452
 453 /* detach a process from a debugger thread (and resume it ?) */
 454 int debugger_detach( struct process *process, struct thread *debugger )
 455 {
 456     struct debug_event *event;
 457     struct debug_ctx *debug_ctx;
 458
 459     if (!process->debugger || process->debugger != debugger)
 460         goto error;  /* not currently debugged, or debugged by another debugger */
 461     if (!debugger->debug_ctx ) goto error; /* should be a debugger */
 462     /* init should be done, otherwise wouldn't be attached */
 463     assert(is_process_init_done(process));
 464
 465     suspend_process( process );
 466     /* send continue indication for all events */
 467     debug_ctx = debugger->debug_ctx;
 468
 469     /* find the event in the queue
 470      * FIXME: could loop on process' threads and look the debug_event field */
 471     for (event = debug_ctx->event_head; event; event = event->next)
 472     {
 473         if (event->state != EVENT_QUEUED) continue;
 474
 475         if (event->sender->process == process)
 476         {
 477             assert( event->sender->debug_event == event );
 478             event->status = DBG_CONTINUE;
 479             event->state  = EVENT_CONTINUED;
 480             wake_up( &event->obj, 0 );
 481             unlink_event( debug_ctx, event );
 482             /* from queued debug event */
 483             resume_process( process );
 484         }
 485     }
 486
 487     /* remove relationships between process and its debugger */
 488     process->debugger = NULL;
 489     if (!set_process_debug_flag( process, 0 )) clear_error();  /* ignore error */
 490     detach_process( process );
 491
 492     /* from this function */
 493     resume_process( process );
 494     return 0;
 495
 496  error:
 497     set_error( STATUS_ACCESS_DENIED );
 498     return 0;
 499 }
 500
 501 /* generate all startup events of a given process */
 502 void generate_startup_debug_events( struct process *process, void *entry )
 503 {
 504     struct process_dll *dll;
 505     struct thread *thread = process->thread_list;
 506
 507     /* generate creation events */
 508     generate_debug_event( thread, CREATE_PROCESS_DEBUG_EVENT, entry );
 509     while ((thread = thread->proc_next))
 510         generate_debug_event( thread, CREATE_THREAD_DEBUG_EVENT, NULL );
 511
 512     /* generate dll events (in loading order, i.e. reverse list order) */
 513     dll = &process->exe;
 514     while (dll->next) dll = dll->next;
 515     while (dll != &process->exe)
 516     {
 517         generate_debug_event( process->thread_list, LOAD_DLL_DEBUG_EVENT, dll );
 518         dll = dll->prev;
 519     }
 520 }
 521
 522 /* set the debugger of a given process */
 523 int set_process_debugger( struct process *process, struct thread *debugger )
 524 {
 525     struct debug_ctx *debug_ctx;
 526
 527     assert( !process->debugger );
 528
 529     if (!debugger->debug_ctx)  /* need to allocate a context */
 530     {
 531         if (!(debug_ctx = alloc_object( &debug_ctx_ops ))) return 0;
 532         debug_ctx->event_head = NULL;
 533         debug_ctx->event_tail = NULL;
 534         debug_ctx->kill_on_exit = 1;
 535         debugger->debug_ctx = debug_ctx;
 536     }
 537     process->debugger = debugger;
 538     return 1;
 539 }
 540
 541 /* a thread is exiting */
 542 void debug_exit_thread( struct thread *thread )
 543 {
 544     if (thread->debug_ctx)  /* this thread is a debugger */
 545     {
 546         if (thread->debug_ctx->kill_on_exit)
 547         {
 548             /* kill all debugged processes */
 549             kill_debugged_processes( thread, thread->exit_code );
 550         }
 551         else
 552         {
 553             detach_debugged_processes( thread );
 554         }
 555         release_object( thread->debug_ctx );
 556         thread->debug_ctx = NULL;
 557     }
 558 }
 559
 560 /* Wait for a debug event */
 561 DECL_HANDLER(wait_debug_event)
 562 {
 563     struct debug_ctx *debug_ctx = current->debug_ctx;
 564     struct debug_event *event;
 565
 566     if (!debug_ctx)  /* current thread is not a debugger */
 567     {
 568         set_error( STATUS_INVALID_HANDLE );
 569         return;
 570     }
 571     reply->wait = 0;
 572     if ((event = find_event_to_send( debug_ctx )))
 573     {
 574         size_t size = get_reply_max_size();
 575         event->state = EVENT_SENT;
 576         event->sender->debug_event = event;
 577         reply->pid = get_process_id( event->sender->process );
 578         reply->tid = get_thread_id( event->sender );
 579         if (size > sizeof(debug_event_t)) size = sizeof(debug_event_t);
 580         set_reply_data( &event->data, size );
 581     }
 582     else  /* no event ready */
 583     {
 584         reply->pid  = 0;
 585         reply->tid  = 0;
 586         if (req->get_handle)
 587             reply->wait = alloc_handle( current->process, debug_ctx, SYNCHRONIZE, FALSE );
 588     }
 589 }
 590
 591 /* Continue a debug event */
 592 DECL_HANDLER(continue_debug_event)
 593 {
 594     struct process *process = get_process_from_id( req->pid );
 595     if (process)
 596     {
 597         struct thread *thread = get_thread_from_id( req->tid );
 598         if (thread)
 599         {
 600             continue_debug_event( process, thread, req->status );
 601             release_object( thread );
 602         }
 603         release_object( process );
 604     }
 605 }
 606
 607 /* Start debugging an existing process */
 608 DECL_HANDLER(debug_process)
 609 {
 610     struct process *process = get_process_from_id( req->pid );
 611     if (!process) return;
 612
 613     if (!req->attach)
 614     {
 615         debugger_detach( process, current );
 616     }
 617     else if (debugger_attach( process, current ))
 618     {
 619         struct debug_event_exception data;
 620
 621         generate_startup_debug_events( process, NULL );
 622         resume_process( process );
 623
 624         data.record.ExceptionCode    = EXCEPTION_BREAKPOINT;
 625         data.record.ExceptionFlags   = EXCEPTION_CONTINUABLE;
 626         data.record.ExceptionRecord  = NULL;
 627         data.record.ExceptionAddress = get_thread_ip( process->thread_list );
 628         data.record.NumberParameters = 0;
 629         data.first = 1;
 630         generate_debug_event( process->thread_list, EXCEPTION_DEBUG_EVENT, &data );
 631     }
 632     release_object( process );
 633 }
 634
 635 /* queue an exception event */
 636 DECL_HANDLER(queue_exception_event)
 637 {
 638     reply->handle = 0;
 639     if (current->process->debugger)
 640     {
 641         struct debug_event_exception data;
 642         struct debug_event *event;
 643         const CONTEXT *context = get_req_data();
 644         EXCEPTION_RECORD *rec = (EXCEPTION_RECORD *)(context + 1);
 645
 646         if (get_req_data_size() < sizeof(*rec) + sizeof(*context))
 647         {
 648             set_error( STATUS_INVALID_PARAMETER );
 649             return;
 650         }
 651         data.record = *rec;
 652         data.first  = req->first;
 653         if ((event = alloc_debug_event( current, EXCEPTION_DEBUG_EVENT, &data, context )))
 654         {
 655             if ((reply->handle = alloc_handle( current->process, event, SYNCHRONIZE, FALSE )))
 656             {
 657                 link_event( event );
 658                 suspend_process( current->process );
 659             }
 660             release_object( event );
 661         }
 662     }
 663 }
 664
 665 /* retrieve the status of an exception event */
 666 DECL_HANDLER(get_exception_status)
 667 {
 668     struct debug_event *event;
 669
 670     reply->status = 0;
 671     if ((event = (struct debug_event *)get_handle_obj( current->process, req->handle,
 672                                                        0, &debug_event_ops )))
 673     {
 674         if (event->state == EVENT_CONTINUED)
 675         {
 676             reply->status = event->status;
 677             if (current->context == &event->context)
 678             {
 679                 size_t size = min( sizeof(CONTEXT), get_reply_max_size() );
 680                 set_reply_data( &event->context, size );
 681                 current->context = NULL;
 682             }
 683         }
 684         else set_error( STATUS_PENDING );
 685         release_object( event );
 686     }
 687 }
 688
 689 /* send an output string to the debugger */
 690 DECL_HANDLER(output_debug_string)
 691 {
 692     struct debug_event_output_string data;
 693
 694     data.string  = req->string;
 695     data.unicode = req->unicode;
 696     data.length  = req->length;
 697     generate_debug_event( current, OUTPUT_DEBUG_STRING_EVENT, &data );
 698 }
 699
 700 /* simulate a breakpoint in a process */
 701 DECL_HANDLER(debug_break)
 702 {
 703     struct process *process;
 704
 705     reply->self = 0;
 706     if (!(process = get_process_from_handle( req->handle, PROCESS_SET_INFORMATION /*FIXME*/ )))
 707         return;
 708     if (process != current->process)
 709     {
 710         /* find a suitable thread to signal */
 711         struct thread *thread;
 712         for (thread = process->thread_list; thread; thread = thread->proc_next)
 713         {
 714             if (send_thread_signal( thread, SIGTRAP )) break;
 715         }
 716         if (!thread) set_error( STATUS_ACCESS_DENIED );
 717     }
 718     else reply->self = 1;
 719     release_object( process );
 720 }
 721
 722 /* set debugger kill on exit flag */
 723 DECL_HANDLER(set_debugger_kill_on_exit)
 724 {
 725     if (!current->debug_ctx)
 726     {
 727         set_error( STATUS_ACCESS_DENIED );
 728         return;
 729     }
 730     current->debug_ctx->kill_on_exit = req->kill_on_exit;
 731 }