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 <stdio.h>
  28
  29 #include "winbase.h"
  30
  31 #include "handle.h"
  32 #include "process.h"
  33 #include "thread.h"
  34 #include "request.h"
  35 #include "console.h"
  36
  37 enum debug_event_state { EVENT_QUEUED, EVENT_SENT, EVENT_CONTINUED };
  38
  39 /* debug event */
  40 struct debug_event
  41 {
  42     struct object          obj;       /* object header */
  43     struct debug_event    *next;      /* event queue */
  44     struct debug_event    *prev;
  45     struct thread         *sender;    /* thread which sent this event */
  46     struct thread         *debugger;  /* debugger thread receiving the event */
  47     enum debug_event_state state;     /* event state */
  48     int                    status;    /* continuation status */
  49     debug_event_t          data;      /* event data */
  50     CONTEXT                context;   /* register context */
  51 };
  52
  53 /* debug context */
  54 struct debug_ctx
  55 {
  56     struct object        obj;         /* object header */
  57     struct debug_event  *event_head;  /* head of pending events queue */
  58     struct debug_event  *event_tail;  /* tail of 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     NULL,                          /* get_poll_events */
  76     NULL,                          /* poll_event */
  77     no_get_fd,                     /* get_fd */
  78     no_flush,                      /* flush */
  79     no_get_file_info,              /* get_file_info */
  80     NULL,                          /* queue_async */
  81     debug_event_destroy            /* destroy */
  82 };
  83
  84 static void debug_ctx_dump( struct object *obj, int verbose );
  85 static int debug_ctx_signaled( struct object *obj, struct thread *thread );
  86 static void debug_ctx_destroy( struct object *obj );
  87
  88 static const struct object_ops debug_ctx_ops =
  89 {
  90     sizeof(struct debug_ctx),      /* size */
  91     debug_ctx_dump,                /* dump */
  92     add_queue,                     /* add_queue */
  93     remove_queue,                  /* remove_queue */
  94     debug_ctx_signaled,            /* signaled */
  95     no_satisfied,                  /* satisfied */
  96     NULL,                          /* get_poll_events */
  97     NULL,                          /* poll_event */
  98     no_get_fd,                     /* get_fd */
  99     no_flush,                      /* flush */
 100     no_get_file_info,              /* get_file_info */
 101     NULL,                          /* queue_async */
 102     debug_ctx_destroy              /* destroy */
 103 };
 104
 105
 106 /* routines to build an event according to its type */
 107
 108 static int fill_exception_event( struct debug_event *event, void *arg )
 109 {
 110     memcpy( &event->data.info.exception, arg, sizeof(event->data.info.exception) );
 111     return 1;
 112 }
 113
 114 static int fill_create_thread_event( struct debug_event *event, void *arg )
 115 {
 116     struct process *debugger = event->debugger->process;
 117     struct thread *thread = event->sender;
 118     obj_handle_t handle;
 119
 120     /* documented: THREAD_GET_CONTEXT | THREAD_SET_CONTEXT | THREAD_SUSPEND_RESUME */
 121     if (!(handle = alloc_handle( debugger, thread, THREAD_ALL_ACCESS, FALSE ))) return 0;
 122     event->data.info.create_thread.handle = handle;
 123     event->data.info.create_thread.teb    = thread->teb;
 124     event->data.info.create_thread.start  = arg;
 125     return 1;
 126 }
 127
 128 static int fill_create_process_event( struct debug_event *event, void *arg )
 129 {
 130     struct process *debugger = event->debugger->process;
 131     struct thread *thread = event->sender;
 132     struct process *process = thread->process;
 133     obj_handle_t handle;
 134
 135     /* documented: PROCESS_VM_READ | PROCESS_VM_WRITE */
 136     if (!(handle = alloc_handle( debugger, process, PROCESS_ALL_ACCESS, FALSE ))) return 0;
 137     event->data.info.create_process.process = handle;
 138
 139     /* documented: THREAD_GET_CONTEXT | THREAD_SET_CONTEXT | THREAD_SUSPEND_RESUME */
 140     if (!(handle = alloc_handle( debugger, thread, THREAD_ALL_ACCESS, FALSE )))
 141     {
 142         close_handle( debugger, event->data.info.create_process.process, NULL );
 143         return 0;
 144     }
 145     event->data.info.create_process.thread = handle;
 146
 147     handle = 0;
 148     if (process->exe.file &&
 149         /* the doc says write access too, but this doesn't seem a good idea */
 150         !(handle = alloc_handle( debugger, process->exe.file, GENERIC_READ, FALSE )))
 151     {
 152         close_handle( debugger, event->data.info.create_process.process, NULL );
 153         close_handle( debugger, event->data.info.create_process.thread, NULL );
 154         return 0;
 155     }
 156     event->data.info.create_process.file       = handle;
 157     event->data.info.create_process.teb        = thread->teb;
 158     event->data.info.create_process.base       = process->exe.base;
 159     event->data.info.create_process.start      = arg;
 160     event->data.info.create_process.dbg_offset = process->exe.dbg_offset;
 161     event->data.info.create_process.dbg_size   = process->exe.dbg_size;
 162     event->data.info.create_process.name       = process->exe.name;
 163     event->data.info.create_process.unicode    = 0;
 164     return 1;
 165 }
 166
 167 static int fill_exit_thread_event( struct debug_event *event, void *arg )
 168 {
 169     struct thread *thread = arg;
 170     event->data.info.exit.exit_code = thread->exit_code;
 171     return 1;
 172 }
 173
 174 static int fill_exit_process_event( struct debug_event *event, void *arg )
 175 {
 176     struct process *process = arg;
 177     event->data.info.exit.exit_code = process->exit_code;
 178     return 1;
 179 }
 180
 181 static int fill_load_dll_event( struct debug_event *event, void *arg )
 182 {
 183     struct process *debugger = event->debugger->process;
 184     struct process_dll *dll = arg;
 185     obj_handle_t handle = 0;
 186
 187     if (dll->file && !(handle = alloc_handle( debugger, dll->file, GENERIC_READ, FALSE )))
 188         return 0;
 189     event->data.info.load_dll.handle     = handle;
 190     event->data.info.load_dll.base       = dll->base;
 191     event->data.info.load_dll.dbg_offset = dll->dbg_offset;
 192     event->data.info.load_dll.dbg_size   = dll->dbg_size;
 193     event->data.info.load_dll.name       = dll->name;
 194     event->data.info.load_dll.unicode    = 0;
 195     return 1;
 196 }
 197
 198 static int fill_unload_dll_event( struct debug_event *event, void *arg )
 199 {
 200     event->data.info.unload_dll.base = arg;
 201     return 1;
 202 }
 203
 204 static int fill_output_debug_string_event( struct debug_event *event, void *arg )
 205 {
 206     struct debug_event_output_string *data = arg;
 207     event->data.info.output_string = *data;
 208     return 1;
 209 }
 210
 211 typedef int (*fill_event_func)( struct debug_event *event, void *arg );
 212
 213 #define NB_DEBUG_EVENTS OUTPUT_DEBUG_STRING_EVENT  /* RIP_EVENT not supported */
 214
 215 static const fill_event_func fill_debug_event[NB_DEBUG_EVENTS] =
 216 {
 217     fill_exception_event,            /* EXCEPTION_DEBUG_EVENT */
 218     fill_create_thread_event,        /* CREATE_THREAD_DEBUG_EVENT */
 219     fill_create_process_event,       /* CREATE_PROCESS_DEBUG_EVENT */
 220     fill_exit_thread_event,          /* EXIT_THREAD_DEBUG_EVENT */
 221     fill_exit_process_event,         /* EXIT_PROCESS_DEBUG_EVENT */
 222     fill_load_dll_event,             /* LOAD_DLL_DEBUG_EVENT */
 223     fill_unload_dll_event,           /* UNLOAD_DLL_DEBUG_EVENT */
 224     fill_output_debug_string_event   /* OUTPUT_DEBUG_STRING_EVENT */
 225 };
 226
 227
 228 /* unlink the first event from the queue */
 229 static void unlink_event( struct debug_ctx *debug_ctx, struct debug_event *event )
 230 {
 231     if (event->prev) event->prev->next = event->next;
 232     else debug_ctx->event_head = event->next;
 233     if (event->next) event->next->prev = event->prev;
 234     else debug_ctx->event_tail = event->prev;
 235     event->next = event->prev = NULL;
 236     if (event->sender->debug_event == event) event->sender->debug_event = NULL;
 237     release_object( event );
 238 }
 239
 240 /* link an event at the end of the queue */
 241 static void link_event( struct debug_event *event )
 242 {
 243     struct debug_ctx *debug_ctx = event->debugger->debug_ctx;
 244
 245     assert( debug_ctx );
 246     grab_object( event );
 247     event->next = NULL;
 248     event->prev = debug_ctx->event_tail;
 249     debug_ctx->event_tail = event;
 250     if (event->prev) event->prev->next = event;
 251     else debug_ctx->event_head = event;
 252     if (!event->sender->debug_event) wake_up( &debug_ctx->obj, 0 );
 253 }
 254
 255 /* find the next event that we can send to the debugger */
 256 static struct debug_event *find_event_to_send( struct debug_ctx *debug_ctx )
 257 {
 258     struct debug_event *event;
 259     for (event = debug_ctx->event_head; event; event = event->next)
 260     {
 261         if (event->state == EVENT_SENT) continue;  /* already sent */
 262         if (event->sender->debug_event) continue;  /* thread busy with another one */
 263         break;
 264     }
 265     return event;
 266 }
 267
 268 static void debug_event_dump( struct object *obj, int verbose )
 269 {
 270     struct debug_event *debug_event = (struct debug_event *)obj;
 271     assert( obj->ops == &debug_event_ops );
 272     fprintf( stderr, "Debug event sender=%p code=%d state=%d\n",
 273              debug_event->sender, debug_event->data.code, debug_event->state );
 274 }
 275
 276 static int debug_event_signaled( struct object *obj, struct thread *thread )
 277 {
 278     struct debug_event *debug_event = (struct debug_event *)obj;
 279     assert( obj->ops == &debug_event_ops );
 280     return debug_event->state == EVENT_CONTINUED;
 281 }
 282
 283 static void debug_event_destroy( struct object *obj )
 284 {
 285     struct debug_event *event = (struct debug_event *)obj;
 286     assert( obj->ops == &debug_event_ops );
 287
 288     /* cannot still be in the queue */
 289     assert( !event->next );
 290     assert( !event->prev );
 291
 292     /* If the event has been sent already, the handles are now under the */
 293     /* responsibility of the debugger process, so we don't touch them    */
 294     if (event->state == EVENT_QUEUED)
 295     {
 296         struct process *debugger = event->debugger->process;
 297         switch(event->data.code)
 298         {
 299         case CREATE_THREAD_DEBUG_EVENT:
 300             close_handle( debugger, event->data.info.create_thread.handle, NULL );
 301             break;
 302         case CREATE_PROCESS_DEBUG_EVENT:
 303             if (event->data.info.create_process.file)
 304                 close_handle( debugger, event->data.info.create_process.file, NULL );
 305             close_handle( debugger, event->data.info.create_process.thread, NULL );
 306             close_handle( debugger, event->data.info.create_process.process, NULL );
 307             break;
 308         case LOAD_DLL_DEBUG_EVENT:
 309             if (event->data.info.load_dll.handle)
 310                 close_handle( debugger, event->data.info.load_dll.handle, NULL );
 311             break;
 312         }
 313     }
 314     if (event->sender->context == &event->context) event->sender->context = NULL;
 315     release_object( event->sender );
 316     release_object( event->debugger );
 317 }
 318
 319 static void debug_ctx_dump( struct object *obj, int verbose )
 320 {
 321     struct debug_ctx *debug_ctx = (struct debug_ctx *)obj;
 322     assert( obj->ops == &debug_ctx_ops );
 323     fprintf( stderr, "Debug context head=%p tail=%p\n",
 324              debug_ctx->event_head, debug_ctx->event_tail );
 325 }
 326
 327 static int debug_ctx_signaled( struct object *obj, struct thread *thread )
 328 {
 329     struct debug_ctx *debug_ctx = (struct debug_ctx *)obj;
 330     assert( obj->ops == &debug_ctx_ops );
 331     return find_event_to_send( debug_ctx ) != NULL;
 332 }
 333
 334 static void debug_ctx_destroy( struct object *obj )
 335 {
 336     struct debug_event *event;
 337     struct debug_ctx *debug_ctx = (struct debug_ctx *)obj;
 338     assert( obj->ops == &debug_ctx_ops );
 339
 340     /* free all pending events */
 341     while ((event = debug_ctx->event_head) != NULL) unlink_event( debug_ctx, event );
 342 }
 343
 344 /* continue a debug event */
 345 static int continue_debug_event( struct process *process, struct thread *thread, int status )
 346 {
 347     struct debug_event *event;
 348     struct debug_ctx *debug_ctx = current->debug_ctx;
 349
 350     if (!debug_ctx || process->debugger != current || thread->process != process) goto error;
 351
 352     /* find the event in the queue */
 353     for (event = debug_ctx->event_head; event; event = event->next)
 354     {
 355         if (event->state != EVENT_SENT) continue;
 356         if (event->sender == thread) break;
 357     }
 358     if (!event) goto error;
 359
 360     assert( event->sender->debug_event == event );
 361
 362     event->status = status;
 363     event->state  = EVENT_CONTINUED;
 364     wake_up( &event->obj, 0 );
 365
 366     unlink_event( debug_ctx, event );
 367     resume_process( process );
 368     return 1;
 369  error:
 370     /* not debugging this process, or no such event */
 371     set_error( STATUS_ACCESS_DENIED );  /* FIXME */
 372     return 0;
 373 }
 374
 375 /* alloc a debug event for a debugger */
 376 static struct debug_event *alloc_debug_event( struct thread *thread, int code,
 377                                               void *arg, const CONTEXT *context )
 378 {
 379     struct thread *debugger = thread->process->debugger;
 380     struct debug_event *event;
 381
 382     assert( code > 0 && code <= NB_DEBUG_EVENTS );
 383     /* cannot queue a debug event for myself */
 384     assert( debugger->process != thread->process );
 385
 386     /* build the event */
 387     if (!(event = alloc_object( &debug_event_ops, -1 ))) return NULL;
 388     event->next      = NULL;
 389     event->prev      = NULL;
 390     event->state     = EVENT_QUEUED;
 391     event->sender    = (struct thread *)grab_object( thread );
 392     event->debugger  = (struct thread *)grab_object( debugger );
 393     event->data.code = code;
 394
 395     if (!fill_debug_event[code-1]( event, arg ))
 396     {
 397         event->data.code = -1;  /* make sure we don't attempt to close handles */
 398         release_object( event );
 399         return NULL;
 400     }
 401     if (context)
 402     {
 403         memcpy( &event->context, context, sizeof(event->context) );
 404         thread->context = &event->context;
 405     }
 406     return event;
 407 }
 408
 409 /* generate a debug event from inside the server and queue it */
 410 void generate_debug_event( struct thread *thread, int code, void *arg )
 411 {
 412     if (thread->process->debugger)
 413     {
 414         struct debug_event *event = alloc_debug_event( thread, code, arg, NULL );
 415         if (event)
 416         {
 417             link_event( event );
 418             suspend_process( thread->process );
 419             release_object( event );
 420         }
 421     }
 422 }
 423
 424 /* attach a process to a debugger thread and suspend it */
 425 static int debugger_attach( struct process *process, struct thread *debugger )
 426 {
 427     struct thread *thread;
 428
 429     if (process->debugger) goto error;  /* already being debugged */
 430     if (!is_process_init_done( process )) goto error;  /* still starting up */
 431     if (!process->thread_list) goto error;  /* no thread running in the process */
 432
 433     /* make sure we don't create a debugging loop */
 434     for (thread = debugger; thread; thread = thread->process->debugger)
 435         if (thread->process == process) goto error;
 436
 437     /* don't let a debugger debug its console... won't work */
 438     if (debugger->process->console && debugger->process->console->renderer->process == process)
 439         goto error;
 440
 441     suspend_process( process );
 442
 443     /* we must have been able to attach all threads */
 444     if (!process->thread_list) goto error2;
 445     for (thread = process->thread_list; thread; thread = thread->proc_next)
 446     {
 447         if (!thread->attached) goto error2;
 448     }
 449
 450     if (set_process_debugger( process, debugger )) return 1;
 451     resume_process( process );
 452     return 0;
 453
 454  error2:
 455     resume_process( process );
 456  error:
 457     set_error( STATUS_ACCESS_DENIED );
 458     return 0;
 459 }
 460
 461
 462 /* detach a process from a debugger thread (and resume it ?) */
 463 int debugger_detach( struct process *process, struct thread *debugger )
 464 {
 465     struct thread *thread;
 466     struct debug_event *event;
 467     struct debug_ctx *debug_ctx;
 468
 469     if (!process->debugger || process->debugger != debugger)
 470         goto error;  /* not currently debugged, or debugged by another debugger */
 471     if (!debugger->debug_ctx ) goto error; /* should be a debugger */
 472     /* init should be done, otherwise wouldn't be attached */
 473     assert(is_process_init_done(process));
 474
 475     suspend_process( process );
 476     /* send continue indication for all events */
 477     debug_ctx = debugger->debug_ctx;
 478
 479     /* find the event in the queue
 480      * FIXME: could loop on process' threads and look the debug_event field */
 481     for (event = debug_ctx->event_head; event; event = event->next)
 482     {
 483         if (event->state != EVENT_QUEUED) continue;
 484
 485         if (event->sender->process == process)
 486         {
 487             assert( event->sender->debug_event == event );
 488             event->status = DBG_CONTINUE;
 489             event->state  = EVENT_CONTINUED;
 490             wake_up( &event->obj, 0 );
 491             unlink_event( debug_ctx, event );
 492             /* from queued debug event */
 493             resume_process( process );
 494         }
 495     }
 496
 497     /* remove relationships between process and its debugger */
 498     process->debugger = NULL;
 499     release_object( debugger->debug_ctx );
 500     debugger->debug_ctx = NULL;
 501
 502     /* now detach all the threads */
 503     for (thread = process->thread_list; thread; thread = thread->proc_next)
 504     {
 505         if (thread->attached)
 506         {
 507             detach_thread( thread, 0 );
 508         }
 509     }
 510
 511     /* from this function */
 512     resume_process( process );
 513     return 0;
 514
 515  error:
 516     set_error( STATUS_ACCESS_DENIED );
 517     return 0;
 518 }
 519
 520 /* generate all startup events of a given process */
 521 void generate_startup_debug_events( struct process *process, void *entry )
 522 {
 523     struct process_dll *dll;
 524     struct thread *thread = process->thread_list;
 525
 526     /* generate creation events */
 527     generate_debug_event( thread, CREATE_PROCESS_DEBUG_EVENT, entry );
 528     while ((thread = thread->proc_next))
 529         generate_debug_event( thread, CREATE_THREAD_DEBUG_EVENT, NULL );
 530
 531     /* generate dll events (in loading order, i.e. reverse list order) */
 532     dll = &process->exe;
 533     while (dll->next) dll = dll->next;
 534     while (dll != &process->exe)
 535     {
 536         generate_debug_event( process->thread_list, LOAD_DLL_DEBUG_EVENT, dll );
 537         dll = dll->prev;
 538     }
 539 }
 540
 541 /* set the debugger of a given process */
 542 int set_process_debugger( struct process *process, struct thread *debugger )
 543 {
 544     struct debug_ctx *debug_ctx;
 545
 546     assert( !process->debugger );
 547
 548     if (!debugger->debug_ctx)  /* need to allocate a context */
 549     {
 550         if (!(debug_ctx = alloc_object( &debug_ctx_ops, -1 ))) return 0;
 551         debug_ctx->event_head = NULL;
 552         debug_ctx->event_tail = NULL;
 553         debug_ctx->kill_on_exit = 1;
 554         debugger->debug_ctx = debug_ctx;
 555     }
 556     process->debugger = debugger;
 557     return 1;
 558 }
 559
 560 /* a thread is exiting */
 561 void debug_exit_thread( struct thread *thread )
 562 {
 563     if (thread->debug_ctx)  /* this thread is a debugger */
 564     {
 565         if (thread->debug_ctx->kill_on_exit)
 566         {
 567             /* kill all debugged processes */
 568             kill_debugged_processes( thread, thread->exit_code );
 569         }
 570         else
 571         {
 572             detach_debugged_processes( thread );
 573         }
 574         release_object( thread->debug_ctx );
 575         thread->debug_ctx = NULL;
 576     }
 577 }
 578
 579 /* Wait for a debug event */
 580 DECL_HANDLER(wait_debug_event)
 581 {
 582     struct debug_ctx *debug_ctx = current->debug_ctx;
 583     struct debug_event *event;
 584
 585     if (!debug_ctx)  /* current thread is not a debugger */
 586     {
 587         set_error( STATUS_INVALID_HANDLE );
 588         return;
 589     }
 590     reply->wait = 0;
 591     if ((event = find_event_to_send( debug_ctx )))
 592     {
 593         size_t size = get_reply_max_size();
 594         event->state = EVENT_SENT;
 595         event->sender->debug_event = event;
 596         reply->pid = get_process_id( event->sender->process );
 597         reply->tid = get_thread_id( event->sender );
 598         if (size > sizeof(debug_event_t)) size = sizeof(debug_event_t);
 599         set_reply_data( &event->data, size );
 600     }
 601     else  /* no event ready */
 602     {
 603         reply->pid  = 0;
 604         reply->tid  = 0;
 605         if (req->get_handle)
 606             reply->wait = alloc_handle( current->process, debug_ctx, SYNCHRONIZE, FALSE );
 607     }
 608 }
 609
 610 /* Continue a debug event */
 611 DECL_HANDLER(continue_debug_event)
 612 {
 613     struct process *process = get_process_from_id( req->pid );
 614     if (process)
 615     {
 616         struct thread *thread = get_thread_from_id( req->tid );
 617         if (thread)
 618         {
 619             continue_debug_event( process, thread, req->status );
 620             release_object( thread );
 621         }
 622         release_object( process );
 623     }
 624 }
 625
 626 /* Start debugging an existing process */
 627 DECL_HANDLER(debug_process)
 628 {
 629     struct process *process = get_process_from_id( req->pid );
 630     if (!process) return;
 631
 632     if (!req->attach)
 633     {
 634         debugger_detach( process, current );
 635     }
 636     else if (debugger_attach( process, current ))
 637     {
 638         struct debug_event_exception data;
 639
 640         generate_startup_debug_events( process, NULL );
 641         resume_process( process );
 642
 643         data.record.ExceptionCode    = EXCEPTION_BREAKPOINT;
 644         data.record.ExceptionFlags   = EXCEPTION_CONTINUABLE;
 645         data.record.ExceptionRecord  = NULL;
 646         data.record.ExceptionAddress = get_thread_ip( process->thread_list );
 647         data.record.NumberParameters = 0;
 648         data.first = 1;
 649         generate_debug_event( process->thread_list, EXCEPTION_DEBUG_EVENT, &data );
 650     }
 651     release_object( process );
 652 }
 653
 654 /* queue an exception event */
 655 DECL_HANDLER(queue_exception_event)
 656 {
 657     reply->handle = 0;
 658     if (current->process->debugger)
 659     {
 660         struct debug_event_exception data;
 661         struct debug_event *event;
 662         const CONTEXT *context = get_req_data();
 663         EXCEPTION_RECORD *rec = (EXCEPTION_RECORD *)(context + 1);
 664
 665         if (get_req_data_size() < sizeof(*rec) + sizeof(*context))
 666         {
 667             set_error( STATUS_INVALID_PARAMETER );
 668             return;
 669         }
 670         data.record = *rec;
 671         data.first  = req->first;
 672         if ((event = alloc_debug_event( current, EXCEPTION_DEBUG_EVENT, &data, context )))
 673         {
 674             if ((reply->handle = alloc_handle( current->process, event, SYNCHRONIZE, FALSE )))
 675             {
 676                 link_event( event );
 677                 suspend_process( current->process );
 678             }
 679             release_object( event );
 680         }
 681     }
 682 }
 683
 684 /* retrieve the status of an exception event */
 685 DECL_HANDLER(get_exception_status)
 686 {
 687     struct debug_event *event;
 688
 689     reply->status = 0;
 690     if ((event = (struct debug_event *)get_handle_obj( current->process, req->handle,
 691                                                        0, &debug_event_ops )))
 692     {
 693         if (event->state == EVENT_CONTINUED)
 694         {
 695             reply->status = event->status;
 696             if (current->context == &event->context)
 697             {
 698                 size_t size = min( sizeof(CONTEXT), get_reply_max_size() );
 699                 set_reply_data( &event->context, size );
 700                 current->context = NULL;
 701             }
 702         }
 703         else set_error( STATUS_PENDING );
 704         release_object( event );
 705     }
 706 }
 707
 708 /* send an output string to the debugger */
 709 DECL_HANDLER(output_debug_string)
 710 {
 711     struct debug_event_output_string data;
 712
 713     data.string  = req->string;
 714     data.unicode = req->unicode;
 715     data.length  = req->length;
 716     generate_debug_event( current, OUTPUT_DEBUG_STRING_EVENT, &data );
 717 }
 718
 719 /* simulate a breakpoint in a process */
 720 DECL_HANDLER(debug_break)
 721 {
 722     struct process *process;
 723
 724     reply->self = 0;
 725     if (!(process = get_process_from_handle( req->handle, PROCESS_SET_INFORMATION /*FIXME*/ )))
 726         return;
 727     if (process != current->process)
 728     {
 729         /* find a suitable thread to signal */
 730         struct thread *thread;
 731         for (thread = process->thread_list; thread; thread = thread->proc_next)
 732         {
 733             if (thread->unix_pid)
 734             {
 735                 kill( thread->unix_pid, SIGTRAP );
 736                 break;
 737             }
 738         }
 739         if (!thread) set_error( STATUS_ACCESS_DENIED );
 740     }
 741     else reply->self = 1;
 742     release_object( process );
 743 }
 744
 745 /* set debugger kill on exit flag */
 746 DECL_HANDLER(set_debugger_kill_on_exit)
 747 {
 748     if (!current->debug_ctx)
 749     {
 750         set_error( STATUS_ACCESS_DENIED );
 751         return;
 752     }
 753     current->debug_ctx->kill_on_exit = req->kill_on_exit;
 754 }