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 <assert.h>
  22 #include <signal.h>
  23 #include <string.h>
  24 #include <stdio.h>
  25
  26 #include "winbase.h"
  27
  28 #include "handle.h"
  29 #include "process.h"
  30 #include "thread.h"
  31 #include "request.h"
  32 #include "console.h"
  33
  34 enum debug_event_state { EVENT_QUEUED, EVENT_SENT, EVENT_CONTINUED };
  35
  36 /* debug event */
  37 struct debug_event
  38 {
  39     struct object          obj;       /* object header */
  40     struct debug_event    *next;      /* event queue */
  41     struct debug_event    *prev;
  42     struct thread         *sender;    /* thread which sent this event */
  43     struct thread         *debugger;  /* debugger thread receiving the event */
  44     enum debug_event_state state;     /* event state */
  45     int                    status;    /* continuation status */
  46     debug_event_t          data;      /* event data */
  47     CONTEXT                context;   /* register context */
  48 };
  49
  50 /* debug context */
  51 struct debug_ctx
  52 {
  53     struct object        obj;         /* object header */
  54     struct debug_event  *event_head;  /* head of pending events queue */
  55     struct debug_event  *event_tail;  /* tail of pending events queue */
  56     int                  kill_on_exit;/* kill debuggees on debugger exit ? */
  57 };
  58
  59
  60 static void debug_event_dump( struct object *obj, int verbose );
  61 static int debug_event_signaled( struct object *obj, struct thread *thread );
  62 static void debug_event_destroy( struct object *obj );
  63
  64 static const struct object_ops debug_event_ops =
  65 {
  66     sizeof(struct debug_event),    /* size */
  67     debug_event_dump,              /* dump */
  68     add_queue,                     /* add_queue */
  69     remove_queue,                  /* remove_queue */
  70     debug_event_signaled,          /* signaled */
  71     no_satisfied,                  /* satisfied */
  72     NULL,                          /* get_poll_events */
  73     NULL,                          /* poll_event */
  74     no_get_fd,                     /* get_fd */
  75     no_flush,                      /* flush */
  76     no_get_file_info,              /* get_file_info */
  77     NULL,                          /* queue_async */
  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     NULL,                          /* get_poll_events */
  94     NULL,                          /* poll_event */
  95     no_get_fd,                     /* get_fd */
  96     no_flush,                      /* flush */
  97     no_get_file_info,              /* get_file_info */
  98     NULL,                          /* queue_async */
  99     debug_ctx_destroy              /* destroy */
 100 };
 101
 102
 103 /* routines to build an event according to its type */
 104
 105 static int fill_exception_event( struct debug_event *event, void *arg )
 106 {
 107     memcpy( &event->data.info.exception, arg, sizeof(event->data.info.exception) );
 108     return 1;
 109 }
 110
 111 static int fill_create_thread_event( struct debug_event *event, void *arg )
 112 {
 113     struct process *debugger = event->debugger->process;
 114     struct thread *thread = event->sender;
 115     handle_t handle;
 116
 117     /* documented: THREAD_GET_CONTEXT | THREAD_SET_CONTEXT | THREAD_SUSPEND_RESUME */
 118     if (!(handle = alloc_handle( debugger, thread, THREAD_ALL_ACCESS, FALSE ))) return 0;
 119     event->data.info.create_thread.handle = handle;
 120     event->data.info.create_thread.teb    = thread->teb;
 121     event->data.info.create_thread.start  = arg;
 122     return 1;
 123 }
 124
 125 static int fill_create_process_event( struct debug_event *event, void *arg )
 126 {
 127     struct process *debugger = event->debugger->process;
 128     struct thread *thread = event->sender;
 129     struct process *process = thread->process;
 130     handle_t handle;
 131
 132     /* documented: PROCESS_VM_READ | PROCESS_VM_WRITE */
 133     if (!(handle = alloc_handle( debugger, process, PROCESS_ALL_ACCESS, FALSE ))) return 0;
 134     event->data.info.create_process.process = handle;
 135
 136     /* documented: THREAD_GET_CONTEXT | THREAD_SET_CONTEXT | THREAD_SUSPEND_RESUME */
 137     if (!(handle = alloc_handle( debugger, thread, THREAD_ALL_ACCESS, FALSE )))
 138     {
 139         close_handle( debugger, event->data.info.create_process.process, NULL );
 140         return 0;
 141     }
 142     event->data.info.create_process.thread = handle;
 143
 144     handle = 0;
 145     if (process->exe.file &&
 146         /* the doc says write access too, but this doesn't seem a good idea */
 147         !(handle = alloc_handle( debugger, process->exe.file, GENERIC_READ, FALSE )))
 148     {
 149         close_handle( debugger, event->data.info.create_process.process, NULL );
 150         close_handle( debugger, event->data.info.create_process.thread, NULL );
 151         return 0;
 152     }
 153     event->data.info.create_process.file       = handle;
 154     event->data.info.create_process.teb        = thread->teb;
 155     event->data.info.create_process.base       = process->exe.base;
 156     event->data.info.create_process.start      = arg;
 157     event->data.info.create_process.dbg_offset = process->exe.dbg_offset;
 158     event->data.info.create_process.dbg_size   = process->exe.dbg_size;
 159     event->data.info.create_process.name       = process->exe.name;
 160     event->data.info.create_process.unicode    = 0;
 161     return 1;
 162 }
 163
 164 static int fill_exit_thread_event( struct debug_event *event, void *arg )
 165 {
 166     struct thread *thread = arg;
 167     event->data.info.exit.exit_code = thread->exit_code;
 168     return 1;
 169 }
 170
 171 static int fill_exit_process_event( struct debug_event *event, void *arg )
 172 {
 173     struct process *process = arg;
 174     event->data.info.exit.exit_code = process->exit_code;
 175     return 1;
 176 }
 177
 178 static int fill_load_dll_event( struct debug_event *event, void *arg )
 179 {
 180     struct process *debugger = event->debugger->process;
 181     struct process_dll *dll = arg;
 182     handle_t handle = 0;
 183
 184     if (dll->file && !(handle = alloc_handle( debugger, dll->file, GENERIC_READ, FALSE )))
 185         return 0;
 186     event->data.info.load_dll.handle     = handle;
 187     event->data.info.load_dll.base       = dll->base;
 188     event->data.info.load_dll.dbg_offset = dll->dbg_offset;
 189     event->data.info.load_dll.dbg_size   = dll->dbg_size;
 190     event->data.info.load_dll.name       = dll->name;
 191     event->data.info.load_dll.unicode    = 0;
 192     return 1;
 193 }
 194
 195 static int fill_unload_dll_event( struct debug_event *event, void *arg )
 196 {
 197     event->data.info.unload_dll.base = arg;
 198     return 1;
 199 }
 200
 201 static int fill_output_debug_string_event( struct debug_event *event, void *arg )
 202 {
 203     struct debug_event_output_string *data = arg;
 204     event->data.info.output_string = *data;
 205     return 1;
 206 }
 207
 208 typedef int (*fill_event_func)( struct debug_event *event, void *arg );
 209
 210 #define NB_DEBUG_EVENTS OUTPUT_DEBUG_STRING_EVENT  /* RIP_EVENT not supported */
 211
 212 static const fill_event_func fill_debug_event[NB_DEBUG_EVENTS] =
 213 {
 214     fill_exception_event,            /* EXCEPTION_DEBUG_EVENT */
 215     fill_create_thread_event,        /* CREATE_THREAD_DEBUG_EVENT */
 216     fill_create_process_event,       /* CREATE_PROCESS_DEBUG_EVENT */
 217     fill_exit_thread_event,          /* EXIT_THREAD_DEBUG_EVENT */
 218     fill_exit_process_event,         /* EXIT_PROCESS_DEBUG_EVENT */
 219     fill_load_dll_event,             /* LOAD_DLL_DEBUG_EVENT */
 220     fill_unload_dll_event,           /* UNLOAD_DLL_DEBUG_EVENT */
 221     fill_output_debug_string_event   /* OUTPUT_DEBUG_STRING_EVENT */
 222 };
 223
 224
 225 /* unlink the first event from the queue */
 226 static void unlink_event( struct debug_ctx *debug_ctx, struct debug_event *event )
 227 {
 228     if (event->prev) event->prev->next = event->next;
 229     else debug_ctx->event_head = event->next;
 230     if (event->next) event->next->prev = event->prev;
 231     else debug_ctx->event_tail = event->prev;
 232     event->next = event->prev = NULL;
 233     if (event->sender->debug_event == event) event->sender->debug_event = NULL;
 234     release_object( event );
 235 }
 236
 237 /* link an event at the end of the queue */
 238 static void link_event( struct debug_event *event )
 239 {
 240     struct debug_ctx *debug_ctx = event->debugger->debug_ctx;
 241
 242     assert( debug_ctx );
 243     grab_object( event );
 244     event->next = NULL;
 245     event->prev = debug_ctx->event_tail;
 246     debug_ctx->event_tail = event;
 247     if (event->prev) event->prev->next = event;
 248     else debug_ctx->event_head = event;
 249     if (!event->sender->debug_event) wake_up( &debug_ctx->obj, 0 );
 250 }
 251
 252 /* find the next event that we can send to the debugger */
 253 static struct debug_event *find_event_to_send( struct debug_ctx *debug_ctx )
 254 {
 255     struct debug_event *event;
 256     for (event = debug_ctx->event_head; event; event = event->next)
 257     {
 258         if (event->state == EVENT_SENT) continue;  /* already sent */
 259         if (event->sender->debug_event) continue;  /* thread busy with another one */
 260         break;
 261     }
 262     return event;
 263 }
 264
 265 static void debug_event_dump( struct object *obj, int verbose )
 266 {
 267     struct debug_event *debug_event = (struct debug_event *)obj;
 268     assert( obj->ops == &debug_event_ops );
 269     fprintf( stderr, "Debug event sender=%p code=%d state=%d\n",
 270              debug_event->sender, debug_event->data.code, debug_event->state );
 271 }
 272
 273 static int debug_event_signaled( struct object *obj, struct thread *thread )
 274 {
 275     struct debug_event *debug_event = (struct debug_event *)obj;
 276     assert( obj->ops == &debug_event_ops );
 277     return debug_event->state == EVENT_CONTINUED;
 278 }
 279
 280 static void debug_event_destroy( struct object *obj )
 281 {
 282     struct debug_event *event = (struct debug_event *)obj;
 283     assert( obj->ops == &debug_event_ops );
 284
 285     /* cannot still be in the queue */
 286     assert( !event->next );
 287     assert( !event->prev );
 288
 289     /* If the event has been sent already, the handles are now under the */
 290     /* responsibility of the debugger process, so we don't touch them    */
 291     if (event->state == EVENT_QUEUED)
 292     {
 293         struct process *debugger = event->debugger->process;
 294         switch(event->data.code)
 295         {
 296         case CREATE_THREAD_DEBUG_EVENT:
 297             close_handle( debugger, event->data.info.create_thread.handle, NULL );
 298             break;
 299         case CREATE_PROCESS_DEBUG_EVENT:
 300             if (event->data.info.create_process.file)
 301                 close_handle( debugger, event->data.info.create_process.file, NULL );
 302             close_handle( debugger, event->data.info.create_process.thread, NULL );
 303             close_handle( debugger, event->data.info.create_process.process, NULL );
 304             break;
 305         case LOAD_DLL_DEBUG_EVENT:
 306             if (event->data.info.load_dll.handle)
 307                 close_handle( debugger, event->data.info.load_dll.handle, NULL );
 308             break;
 309         }
 310     }
 311     if (event->sender->context == &event->context) event->sender->context = NULL;
 312     release_object( event->sender );
 313     release_object( event->debugger );
 314 }
 315
 316 static void debug_ctx_dump( struct object *obj, int verbose )
 317 {
 318     struct debug_ctx *debug_ctx = (struct debug_ctx *)obj;
 319     assert( obj->ops == &debug_ctx_ops );
 320     fprintf( stderr, "Debug context head=%p tail=%p\n",
 321              debug_ctx->event_head, debug_ctx->event_tail );
 322 }
 323
 324 static int debug_ctx_signaled( struct object *obj, struct thread *thread )
 325 {
 326     struct debug_ctx *debug_ctx = (struct debug_ctx *)obj;
 327     assert( obj->ops == &debug_ctx_ops );
 328     return find_event_to_send( debug_ctx ) != NULL;
 329 }
 330
 331 static void debug_ctx_destroy( struct object *obj )
 332 {
 333     struct debug_event *event;
 334     struct debug_ctx *debug_ctx = (struct debug_ctx *)obj;
 335     assert( obj->ops == &debug_ctx_ops );
 336
 337     /* free all pending events */
 338     while ((event = debug_ctx->event_head) != NULL) unlink_event( debug_ctx, event );
 339 }
 340
 341 /* continue a debug event */
 342 static int continue_debug_event( struct process *process, struct thread *thread, int status )
 343 {
 344     struct debug_event *event;
 345     struct debug_ctx *debug_ctx = current->debug_ctx;
 346
 347     if (!debug_ctx || process->debugger != current || thread->process != process) goto error;
 348
 349     /* find the event in the queue */
 350     for (event = debug_ctx->event_head; event; event = event->next)
 351     {
 352         if (event->state != EVENT_SENT) continue;
 353         if (event->sender == thread) break;
 354     }
 355     if (!event) goto error;
 356
 357     assert( event->sender->debug_event == event );
 358
 359     event->status = status;
 360     event->state  = EVENT_CONTINUED;
 361     wake_up( &event->obj, 0 );
 362
 363     unlink_event( debug_ctx, event );
 364     resume_process( process );
 365     return 1;
 366  error:
 367     /* not debugging this process, or no such event */
 368     set_error( STATUS_ACCESS_DENIED );  /* FIXME */
 369     return 0;
 370 }
 371
 372 /* alloc a debug event for a debugger */
 373 static struct debug_event *alloc_debug_event( struct thread *thread, int code,
 374                                               void *arg, const CONTEXT *context )
 375 {
 376     struct thread *debugger = thread->process->debugger;
 377     struct debug_event *event;
 378
 379     assert( code > 0 && code <= NB_DEBUG_EVENTS );
 380     /* cannot queue a debug event for myself */
 381     assert( debugger->process != thread->process );
 382
 383     /* build the event */
 384     if (!(event = alloc_object( &debug_event_ops, -1 ))) return NULL;
 385     event->next      = NULL;
 386     event->prev      = NULL;
 387     event->state     = EVENT_QUEUED;
 388     event->sender    = (struct thread *)grab_object( thread );
 389     event->debugger  = (struct thread *)grab_object( debugger );
 390     event->data.code = code;
 391
 392     if (!fill_debug_event[code-1]( event, arg ))
 393     {
 394         event->data.code = -1;  /* make sure we don't attempt to close handles */
 395         release_object( event );
 396         return NULL;
 397     }
 398     if (context)
 399     {
 400         memcpy( &event->context, context, sizeof(event->context) );
 401         thread->context = &event->context;
 402     }
 403     return event;
 404 }
 405
 406 /* generate a debug event from inside the server and queue it */
 407 void generate_debug_event( struct thread *thread, int code, void *arg )
 408 {
 409     if (thread->process->debugger)
 410     {
 411         struct debug_event *event = alloc_debug_event( thread, code, arg, NULL );
 412         if (event)
 413         {
 414             link_event( event );
 415             suspend_process( thread->process );
 416             release_object( event );
 417         }
 418     }
 419 }
 420
 421 /* attach a process to a debugger thread and suspend it */
 422 static int debugger_attach( struct process *process, struct thread *debugger )
 423 {
 424     struct thread *thread;
 425
 426     if (process->debugger) goto error;  /* already being debugged */
 427     if (process->init_event) goto error;  /* still starting up */
 428
 429     /* make sure we don't create a debugging loop */
 430     for (thread = debugger; thread; thread = thread->process->debugger)
 431         if (thread->process == process) goto error;
 432
 433     /* don't let a debugger debug its console... won't work */
 434     if (debugger->process->console && debugger->process->console->renderer->process == process)
 435         goto error;
 436
 437     suspend_process( process );
 438
 439     /* we must have been able to attach all threads */
 440     for (thread = process->thread_list; thread; thread = thread->proc_next)
 441     {
 442         if (!thread->attached)
 443         {
 444             resume_process( process );
 445             goto error;
 446         }
 447     }
 448
 449     if (set_process_debugger( process, debugger )) return 1;
 450     resume_process( process );
 451     return 0;
 452
 453  error:
 454     set_error( STATUS_ACCESS_DENIED );
 455     return 0;
 456 }
 457
 458
 459 /* detach a process from a debugger thread (and resume it ?) */
 460 int debugger_detach( struct process *process, struct thread *debugger )
 461 {
 462     struct thread *thread;
 463     struct debug_event *event;
 464     struct debug_ctx *debug_ctx;
 465
 466     if (!process->debugger || process->debugger != debugger)
 467         goto error;  /* not currently debugged, or debugged by another debugger */
 468     if (!debugger->debug_ctx ) goto error; /* should be a debugger */
 469     /* init should be done, otherwise wouldn't be attached */
 470     assert(!process->init_event);
 471
 472     suspend_process( process );
 473     /* send continue indication for all events */
 474     debug_ctx = debugger->debug_ctx;
 475
 476     /* find the event in the queue
 477      * FIXME: could loop on process' threads and look the debug_event field */
 478     for (event = debug_ctx->event_head; event; event = event->next)
 479     {
 480         if (event->state != EVENT_QUEUED) continue;
 481
 482         if (event->sender->process == process)
 483         {
 484             assert( event->sender->debug_event == event );
 485             event->status = DBG_CONTINUE;
 486             event->state  = EVENT_CONTINUED;
 487             wake_up( &event->obj, 0 );
 488             unlink_event( debug_ctx, event );
 489             /* from queued debug event */
 490             resume_process( process );
 491         }
 492     }
 493
 494     /* remove relationships between process and its debugger */
 495     process->debugger = NULL;
 496     release_object( debugger->debug_ctx );
 497     debugger->debug_ctx = NULL;
 498
 499     /* now detach all the threads */
 500     for (thread = process->thread_list; thread; thread = thread->proc_next)
 501     {
 502         if (thread->attached)
 503         {
 504             detach_thread( thread, 0 );
 505         }
 506     }
 507
 508     /* from this function */
 509     resume_process( process );
 510     return 0;
 511
 512  error:
 513     set_error( STATUS_ACCESS_DENIED );
 514     return 0;
 515 }
 516
 517 /* generate all startup events of a given process */
 518 void generate_startup_debug_events( struct process *process, void *entry )
 519 {
 520     struct process_dll *dll;
 521     struct thread *thread = process->thread_list;
 522
 523     /* generate creation events */
 524     generate_debug_event( thread, CREATE_PROCESS_DEBUG_EVENT, entry );
 525     while ((thread = thread->proc_next))
 526         generate_debug_event( thread, CREATE_THREAD_DEBUG_EVENT, NULL );
 527
 528     /* generate dll events (in loading order, i.e. reverse list order) */
 529     dll = &process->exe;
 530     while (dll->next) dll = dll->next;
 531     while (dll != &process->exe)
 532     {
 533         generate_debug_event( process->thread_list, LOAD_DLL_DEBUG_EVENT, dll );
 534         dll = dll->prev;
 535     }
 536 }
 537
 538 /* set the debugger of a given process */
 539 int set_process_debugger( struct process *process, struct thread *debugger )
 540 {
 541     struct debug_ctx *debug_ctx;
 542
 543     assert( !process->debugger );
 544
 545     if (!debugger->debug_ctx)  /* need to allocate a context */
 546     {
 547         if (!(debug_ctx = alloc_object( &debug_ctx_ops, -1 ))) return 0;
 548         debug_ctx->event_head = NULL;
 549         debug_ctx->event_tail = NULL;
 550         debug_ctx->kill_on_exit = 1;
 551         debugger->debug_ctx = debug_ctx;
 552     }
 553     process->debugger = debugger;
 554     return 1;
 555 }
 556
 557 /* a thread is exiting */
 558 void debug_exit_thread( struct thread *thread )
 559 {
 560     if (thread->debug_ctx)  /* this thread is a debugger */
 561     {
 562         if (thread->debug_ctx->kill_on_exit)
 563         {
 564             /* kill all debugged processes */
 565             kill_debugged_processes( thread, thread->exit_code );
 566         }
 567         else
 568         {
 569             detach_debugged_processes( thread );
 570         }
 571         release_object( thread->debug_ctx );
 572         thread->debug_ctx = NULL;
 573     }
 574 }
 575
 576 /* Wait for a debug event */
 577 DECL_HANDLER(wait_debug_event)
 578 {
 579     struct debug_ctx *debug_ctx = current->debug_ctx;
 580     struct debug_event *event;
 581
 582     if (!debug_ctx)  /* current thread is not a debugger */
 583     {
 584         set_error( STATUS_INVALID_HANDLE );
 585         return;
 586     }
 587     reply->wait = 0;
 588     if ((event = find_event_to_send( debug_ctx )))
 589     {
 590         size_t size = get_reply_max_size();
 591         event->state = EVENT_SENT;
 592         event->sender->debug_event = event;
 593         reply->pid = event->sender->process;
 594         reply->tid = event->sender;
 595         if (size > sizeof(debug_event_t)) size = sizeof(debug_event_t);
 596         set_reply_data( &event->data, size );
 597     }
 598     else  /* no event ready */
 599     {
 600         reply->pid  = 0;
 601         reply->tid  = 0;
 602         if (req->get_handle)
 603             reply->wait = alloc_handle( current->process, debug_ctx, SYNCHRONIZE, FALSE );
 604     }
 605 }
 606
 607 /* Continue a debug event */
 608 DECL_HANDLER(continue_debug_event)
 609 {
 610     struct process *process = get_process_from_id( req->pid );
 611     if (process)
 612     {
 613         struct thread *thread = get_thread_from_id( req->tid );
 614         if (thread)
 615         {
 616             continue_debug_event( process, thread, req->status );
 617             release_object( thread );
 618         }
 619         release_object( process );
 620     }
 621 }
 622
 623 /* Start debugging an existing process */
 624 DECL_HANDLER(debug_process)
 625 {
 626     struct process *process = get_process_from_id( req->pid );
 627     if (!process) return;
 628
 629     if (!req->attach)
 630     {
 631         debugger_detach( process, current );
 632     }
 633     else if (debugger_attach( process, current ))
 634     {
 635         struct debug_event_exception data;
 636
 637         generate_startup_debug_events( process, NULL );
 638         resume_process( process );
 639
 640         data.record.ExceptionCode    = EXCEPTION_BREAKPOINT;
 641         data.record.ExceptionFlags   = EXCEPTION_CONTINUABLE;
 642         data.record.ExceptionRecord  = NULL;
 643         data.record.ExceptionAddress = get_thread_ip( process->thread_list );
 644         data.record.NumberParameters = 0;
 645         data.first = 1;
 646         generate_debug_event( process->thread_list, EXCEPTION_DEBUG_EVENT, &data );
 647     }
 648     release_object( process );
 649 }
 650
 651 /* queue an exception event */
 652 DECL_HANDLER(queue_exception_event)
 653 {
 654     reply->handle = 0;
 655     if (current->process->debugger)
 656     {
 657         struct debug_event_exception data;
 658         struct debug_event *event;
 659         const CONTEXT *context = get_req_data();
 660         EXCEPTION_RECORD *rec = (EXCEPTION_RECORD *)(context + 1);
 661
 662         if (get_req_data_size() < sizeof(*rec) + sizeof(*context))
 663         {
 664             set_error( STATUS_INVALID_PARAMETER );
 665             return;
 666         }
 667         data.record = *rec;
 668         data.first  = req->first;
 669         if ((event = alloc_debug_event( current, EXCEPTION_DEBUG_EVENT, &data, context )))
 670         {
 671             if ((reply->handle = alloc_handle( current->process, event, SYNCHRONIZE, FALSE )))
 672             {
 673                 link_event( event );
 674                 suspend_process( current->process );
 675             }
 676             release_object( event );
 677         }
 678     }
 679 }
 680
 681 /* retrieve the status of an exception event */
 682 DECL_HANDLER(get_exception_status)
 683 {
 684     struct debug_event *event;
 685
 686     reply->status = 0;
 687     if ((event = (struct debug_event *)get_handle_obj( current->process, req->handle,
 688                                                        0, &debug_event_ops )))
 689     {
 690         if (event->state == EVENT_CONTINUED)
 691         {
 692             reply->status = event->status;
 693             if (current->context == &event->context)
 694             {
 695                 size_t size = min( sizeof(CONTEXT), get_reply_max_size() );
 696                 set_reply_data( &event->context, size );
 697                 current->context = NULL;
 698             }
 699         }
 700         else set_error( STATUS_PENDING );
 701         release_object( event );
 702     }
 703 }
 704
 705 /* send an output string to the debugger */
 706 DECL_HANDLER(output_debug_string)
 707 {
 708     struct debug_event_output_string data;
 709
 710     data.string  = req->string;
 711     data.unicode = req->unicode;
 712     data.length  = req->length;
 713     generate_debug_event( current, OUTPUT_DEBUG_STRING_EVENT, &data );
 714 }
 715
 716 /* simulate a breakpoint in a process */
 717 DECL_HANDLER(debug_break)
 718 {
 719     struct process *process;
 720
 721     reply->self = 0;
 722     if (!(process = get_process_from_handle( req->handle, PROCESS_SET_INFORMATION /*FIXME*/ )))
 723         return;
 724     if (process != current->process)
 725     {
 726         /* find a suitable thread to signal */
 727         struct thread *thread;
 728         for (thread = process->thread_list; thread; thread = thread->proc_next)
 729         {
 730             if (thread->unix_pid)
 731             {
 732                 kill( thread->unix_pid, SIGTRAP );
 733                 break;
 734             }
 735         }
 736         if (!thread) set_error( STATUS_ACCESS_DENIED );
 737     }
 738     else reply->self = 1;
 739     release_object( process );
 740 }
 741
 742 /* set debugger kill on exit flag */
 743 DECL_HANDLER(set_debugger_kill_on_exit)
 744 {
 745     if (!current->debug_ctx)
 746     {
 747         set_error( STATUS_ACCESS_DENIED );
 748         return;
 749     }
 750     current->debug_ctx->kill_on_exit = req->kill_on_exit;
 751 }