server/debugger.c

   1 /*
   2  * Server-side debugger functions
   3  *
   4  * Copyright (C) 1999 Alexandre Julliard
   5  */
   6
   7 #include <assert.h>
   8 #include <string.h>
   9 #include <stdio.h>
  10
  11 #include "winbase.h"
  12
  13 #include "handle.h"
  14 #include "process.h"
  15 #include "thread.h"
  16 #include "request.h"
  17
  18 enum debug_event_state { EVENT_QUEUED, EVENT_SENT, EVENT_CONTINUED };
  19
  20 /* debug event */
  21 struct debug_event
  22 {
  23     struct object          obj;       /* object header */
  24     struct debug_event    *next;      /* event queue */
  25     struct debug_event    *prev;
  26     struct thread         *sender;    /* thread which sent this event */
  27     struct thread         *debugger;  /* debugger thread receiving the event */
  28     enum debug_event_state state;     /* event state */
  29     int                    status;    /* continuation status */
  30     debug_event_t          data;      /* event data */
  31 };
  32
  33 /* debug context */
  34 struct debug_ctx
  35 {
  36     struct object        obj;         /* object header */
  37     struct debug_event  *event_head;  /* head of pending events queue */
  38     struct debug_event  *event_tail;  /* tail of pending events queue */
  39     struct debug_event  *to_send;     /* next event on the queue to send to debugger */
  40 };
  41
  42
  43 static void debug_event_dump( struct object *obj, int verbose );
  44 static int debug_event_signaled( struct object *obj, struct thread *thread );
  45 static void debug_event_destroy( struct object *obj );
  46
  47 static const struct object_ops debug_event_ops =
  48 {
  49     sizeof(struct debug_event),    /* size */
  50     debug_event_dump,              /* dump */
  51     add_queue,                     /* add_queue */
  52     remove_queue,                  /* remove_queue */
  53     debug_event_signaled,          /* signaled */
  54     no_satisfied,                  /* satisfied */
  55     NULL,                          /* get_poll_events */
  56     NULL,                          /* poll_event */
  57     no_read_fd,                    /* get_read_fd */
  58     no_write_fd,                   /* get_write_fd */
  59     no_flush,                      /* flush */
  60     no_get_file_info,              /* get_file_info */
  61     debug_event_destroy            /* destroy */
  62 };
  63
  64 static void debug_ctx_dump( struct object *obj, int verbose );
  65 static int debug_ctx_signaled( struct object *obj, struct thread *thread );
  66 static void debug_ctx_destroy( struct object *obj );
  67
  68 static const struct object_ops debug_ctx_ops =
  69 {
  70     sizeof(struct debug_ctx),      /* size */
  71     debug_ctx_dump,                /* dump */
  72     add_queue,                     /* add_queue */
  73     remove_queue,                  /* remove_queue */
  74     debug_ctx_signaled,            /* signaled */
  75     no_satisfied,                  /* satisfied */
  76     NULL,                          /* get_poll_events */
  77     NULL,                          /* poll_event */
  78     no_read_fd,                    /* get_read_fd */
  79     no_write_fd,                   /* get_write_fd */
  80     no_flush,                      /* flush */
  81     no_get_file_info,              /* get_file_info */
  82     debug_ctx_destroy              /* destroy */
  83 };
  84
  85
  86 /* initialise the fields that do not need to be filled by the client */
  87 static int fill_debug_event( struct thread *debugger, struct thread *thread,
  88                              struct debug_event *event )
  89 {
  90     int handle;
  91
  92     /* some events need special handling */
  93     switch(event->data.code)
  94     {
  95     case CREATE_THREAD_DEBUG_EVENT:
  96         if ((event->data.info.create_thread.handle = alloc_handle( debugger->process, thread,
  97                /* documented: THREAD_GET_CONTEXT | THREAD_SET_CONTEXT | THREAD_SUSPEND_RESUME */
  98                                                               THREAD_ALL_ACCESS, FALSE )) == -1)
  99             return 0;
 100         break;
 101     case CREATE_PROCESS_DEBUG_EVENT:
 102         if ((handle = event->data.info.create_process.file) != -1)
 103         {
 104             if ((handle = duplicate_handle( thread->process, handle, debugger->process,
 105                                             GENERIC_READ, FALSE, 0 )) == -1)
 106                 return 0;
 107             event->data.info.create_process.file = handle;
 108         }
 109         if ((event->data.info.create_process.process = alloc_handle( debugger->process, thread->process,
 110                                            /* documented: PROCESS_VM_READ | PROCESS_VM_WRITE */
 111                                                                 PROCESS_ALL_ACCESS, FALSE )) == -1)
 112         {
 113             if (handle != -1) close_handle( debugger->process, handle );
 114             return 0;
 115         }
 116         if ((event->data.info.create_process.thread = alloc_handle( debugger->process, thread,
 117                /* documented: THREAD_GET_CONTEXT | THREAD_SET_CONTEXT | THREAD_SUSPEND_RESUME */
 118                                                                THREAD_ALL_ACCESS, FALSE )) == -1)
 119         {
 120             if (handle != -1) close_handle( debugger->process, handle );
 121             close_handle( debugger->process, event->data.info.create_process.process );
 122             return 0;
 123         }
 124         break;
 125     case LOAD_DLL_DEBUG_EVENT:
 126         if ((handle = event->data.info.load_dll.handle) != -1)
 127         {
 128             if ((handle = duplicate_handle( thread->process, handle, debugger->process,
 129                                             GENERIC_READ, FALSE, 0 )) == -1)
 130                 return 0;
 131             event->data.info.load_dll.handle = handle;
 132         }
 133         break;
 134     }
 135     return 1;
 136 }
 137
 138 /* unlink the first event from the queue */
 139 static void unlink_event( struct debug_ctx *debug_ctx, struct debug_event *event )
 140 {
 141     if (event->prev) event->prev->next = event->next;
 142     else debug_ctx->event_head = event->next;
 143     if (event->next) event->next->prev = event->prev;
 144     else debug_ctx->event_tail = event->prev;
 145     if (debug_ctx->to_send == event) debug_ctx->to_send = event->next;
 146     event->next = event->prev = NULL;
 147     release_object( event );
 148 }
 149
 150 /* link an event at the end of the queue */
 151 static void link_event( struct debug_ctx *debug_ctx, struct debug_event *event )
 152 {
 153     grab_object( event );
 154     event->next = NULL;
 155     event->prev = debug_ctx->event_tail;
 156     debug_ctx->event_tail = event;
 157     if (event->prev) event->prev->next = event;
 158     else debug_ctx->event_head = event;
 159     if (!debug_ctx->to_send)
 160     {
 161         debug_ctx->to_send = event;
 162         wake_up( &debug_ctx->obj, 0 );
 163     }
 164 }
 165
 166 /* build a reply for the wait_debug_event request */
 167 static void build_wait_debug_reply( struct thread *thread, struct object *obj, int signaled )
 168 {
 169     struct wait_debug_event_request *req = get_req_ptr( thread );
 170
 171     if (obj)
 172     {
 173         struct debug_ctx *debug_ctx = (struct debug_ctx *)obj;
 174         struct debug_event *event = debug_ctx->to_send;
 175
 176         /* the object that woke us has to be our debug context */
 177         assert( obj->ops == &debug_ctx_ops );
 178         assert( event );
 179
 180         event->state = EVENT_SENT;
 181         debug_ctx->to_send = event->next;
 182         req->event.code = event->data.code;
 183         req->pid  = event->sender->process;
 184         req->tid  = event->sender;
 185         memcpy( &req->event, &event->data, sizeof(req->event) );
 186     }
 187     else  /* timeout or error */
 188     {
 189         req->event.code = 0;
 190         req->pid  = 0;
 191         req->tid  = 0;
 192         thread->error = signaled;
 193     }
 194 }
 195
 196 /* build a reply for the send_event request */
 197 static void build_send_event_reply( struct thread *thread, struct object *obj, int signaled )
 198 {
 199     struct send_debug_event_request *req = get_req_ptr( thread );
 200     struct debug_event *event = (struct debug_event *)obj;
 201     assert( obj->ops == &debug_event_ops );
 202
 203     req->status = event->status;
 204     /* copy the context into the reply */
 205     if (event->data.code == EXCEPTION_DEBUG_EVENT)
 206         memcpy( &req->event.info.exception.context,
 207                 &event->data.info.exception.context,
 208                 sizeof(req->event.info.exception.context) );
 209 }
 210
 211 static void debug_event_dump( struct object *obj, int verbose )
 212 {
 213     struct debug_event *debug_event = (struct debug_event *)obj;
 214     assert( obj->ops == &debug_event_ops );
 215     fprintf( stderr, "Debug event sender=%p code=%d state=%d\n",
 216              debug_event->sender, debug_event->data.code, debug_event->state );
 217 }
 218
 219 static int debug_event_signaled( struct object *obj, struct thread *thread )
 220 {
 221     struct debug_event *debug_event = (struct debug_event *)obj;
 222     assert( obj->ops == &debug_event_ops );
 223     return debug_event->state == EVENT_CONTINUED;
 224 }
 225
 226 static void debug_event_destroy( struct object *obj )
 227 {
 228     struct debug_event *event = (struct debug_event *)obj;
 229     assert( obj->ops == &debug_event_ops );
 230
 231     /* cannot still be in the queue */
 232     assert( !event->next );
 233     assert( !event->prev );
 234
 235     /* If the event has been sent already, the handles are now under the */
 236     /* responsibility of the debugger process, so we don't touch them    */
 237     if (event->state == EVENT_QUEUED)
 238     {
 239         struct process *debugger = event->debugger->process;
 240         switch(event->data.code)
 241         {
 242         case CREATE_THREAD_DEBUG_EVENT:
 243             close_handle( debugger, event->data.info.create_thread.handle );
 244             break;
 245         case CREATE_PROCESS_DEBUG_EVENT:
 246             if (event->data.info.create_process.file != -1)
 247                 close_handle( debugger, event->data.info.create_process.file );
 248             close_handle( debugger, event->data.info.create_process.thread );
 249             close_handle( debugger, event->data.info.create_process.process );
 250             break;
 251         case LOAD_DLL_DEBUG_EVENT:
 252             if (event->data.info.load_dll.handle != -1)
 253                 close_handle( debugger, event->data.info.load_dll.handle );
 254             break;
 255         }
 256     }
 257     release_object( event->sender );
 258     release_object( event->debugger );
 259 }
 260
 261 static void debug_ctx_dump( struct object *obj, int verbose )
 262 {
 263     struct debug_ctx *debug_ctx = (struct debug_ctx *)obj;
 264     assert( obj->ops == &debug_ctx_ops );
 265     fprintf( stderr, "Debug context head=%p tail=%p to_send=%p\n",
 266              debug_ctx->event_head, debug_ctx->event_tail, debug_ctx->to_send );
 267 }
 268
 269 static int debug_ctx_signaled( struct object *obj, struct thread *thread )
 270 {
 271     struct debug_ctx *debug_ctx = (struct debug_ctx *)obj;
 272     assert( obj->ops == &debug_ctx_ops );
 273     return debug_ctx->to_send != NULL;
 274 }
 275
 276 static void debug_ctx_destroy( struct object *obj )
 277 {
 278     struct debug_event *event;
 279     struct debug_ctx *debug_ctx = (struct debug_ctx *)obj;
 280     assert( obj->ops == &debug_ctx_ops );
 281
 282     /* free all pending events */
 283     while ((event = debug_ctx->event_head) != NULL) unlink_event( debug_ctx, event );
 284 }
 285
 286 /* wait for a debug event (or send a reply at once if one is pending) */
 287 static int wait_for_debug_event( int timeout )
 288 {
 289     struct debug_ctx *debug_ctx = current->debug_ctx;
 290     struct object *obj = &debug_ctx->obj;
 291     int flags = 0;
 292
 293     if (!debug_ctx)  /* current thread is not a debugger */
 294     {
 295         set_error( STATUS_INVALID_HANDLE );
 296         return 0;
 297     }
 298     if (timeout != -1) flags = SELECT_TIMEOUT;
 299     return sleep_on( 1, &obj, flags, timeout, build_wait_debug_reply );
 300 }
 301
 302 /* continue a debug event */
 303 static int continue_debug_event( struct process *process, struct thread *thread, int status )
 304 {
 305     struct debug_event *event;
 306     struct debug_ctx *debug_ctx = current->debug_ctx;
 307
 308     if (!debug_ctx || process->debugger != current || thread->process != process) goto error;
 309
 310     /* find the event in the queue */
 311     for (event = debug_ctx->event_head; event; event = event->next)
 312     {
 313         if (event == debug_ctx->to_send) goto error;
 314         if (event->sender == thread) break;
 315         event = event->next;
 316     }
 317     if (!event) goto error;
 318
 319     event->status = status;
 320     event->state  = EVENT_CONTINUED;
 321     wake_up( &event->obj, 0 );
 322
 323     unlink_event( debug_ctx, event );
 324     resume_process( process );
 325     return 1;
 326  error:
 327     /* not debugging this process, or no such event */
 328     set_error( STATUS_ACCESS_DENIED );  /* FIXME */
 329     return 0;
 330 }
 331
 332 /* queue a debug event for a debugger */
 333 static struct debug_event *queue_debug_event( struct thread *debugger, struct thread *thread,
 334                                               debug_event_t *data )
 335 {
 336     struct debug_ctx *debug_ctx = debugger->debug_ctx;
 337     struct debug_event *event;
 338
 339     assert( debug_ctx );
 340     /* cannot queue a debug event for myself */
 341     assert( debugger->process != thread->process );
 342
 343     /* build the event */
 344     if (!(event = alloc_object( &debug_event_ops, -1 ))) return NULL;
 345     event->next     = NULL;
 346     event->prev     = NULL;
 347     event->state    = EVENT_QUEUED;
 348     event->sender   = (struct thread *)grab_object( thread );
 349     event->debugger = (struct thread *)grab_object( debugger );
 350     memcpy( &event->data, data, sizeof(event->data) );
 351
 352     if (!fill_debug_event( debugger, thread, event ))
 353     {
 354         event->data.code = -1;  /* make sure we don't attempt to close handles */
 355         release_object( event );
 356         return NULL;
 357     }
 358
 359     link_event( debug_ctx, event );
 360     suspend_process( thread->process );
 361     return event;
 362 }
 363
 364 /* return a pointer to the context in case the thread is inside an exception event */
 365 CONTEXT *get_debug_context( struct thread *thread )
 366 {
 367     struct debug_event *event;
 368     struct thread *debugger = thread->process->debugger;
 369
 370     if (!debugger) return NULL;  /* not being debugged */
 371     assert( debugger->debug_ctx );
 372
 373     /* find the exception event in the debugger's queue */
 374     for (event = debugger->debug_ctx->event_head; event; event = event->next)
 375         if (event->sender == thread && (event->data.code == EXCEPTION_DEBUG_EVENT))
 376             return &event->data.info.exception.context;
 377     return NULL;
 378 }
 379
 380 /* attach a process to a debugger thread */
 381 int debugger_attach( struct process *process, struct thread *debugger )
 382 {
 383     struct debug_ctx *debug_ctx;
 384     struct thread *thread;
 385
 386     if (process->debugger)  /* already being debugged */
 387     {
 388         set_error( STATUS_ACCESS_DENIED );
 389         return 0;
 390     }
 391     /* make sure we don't create a debugging loop */
 392     for (thread = debugger; thread; thread = thread->process->debugger)
 393         if (thread->process == process)
 394         {
 395             set_error( STATUS_ACCESS_DENIED );
 396             return 0;
 397         }
 398
 399     if (!debugger->debug_ctx)  /* need to allocate a context */
 400     {
 401         if (!(debug_ctx = alloc_object( &debug_ctx_ops, -1 ))) return 0;
 402         debug_ctx->event_head = NULL;
 403         debug_ctx->event_tail = NULL;
 404         debug_ctx->to_send    = NULL;
 405         debugger->debug_ctx = debug_ctx;
 406     }
 407     process->debugger = debugger;
 408     return 1;
 409 }
 410
 411 /* a thread is exiting */
 412 void debug_exit_thread( struct thread *thread, int exit_code )
 413 {
 414     struct thread *debugger = thread->process->debugger;
 415     struct debug_ctx *debug_ctx = thread->debug_ctx;
 416
 417     if (debugger)  /* being debugged -> send an event to the debugger */
 418     {
 419         struct debug_event *event;
 420         debug_event_t exit;
 421         exit.info.exit.exit_code = exit_code;
 422         /* if this is the last thread, send an exit process event */
 423         exit.code = ((thread->process->running_threads == 1) ?
 424                      EXIT_PROCESS_DEBUG_EVENT : EXIT_THREAD_DEBUG_EVENT);
 425         event = queue_debug_event( debugger, thread, &exit );
 426         if (event) release_object( event );
 427     }
 428
 429     if (debug_ctx)  /* this thread is a debugger */
 430     {
 431         /* kill all debugged processes */
 432         kill_debugged_processes( thread, exit_code );
 433         thread->debug_ctx = NULL;
 434         release_object( debug_ctx );
 435     }
 436 }
 437
 438 /* Wait for a debug event */
 439 DECL_HANDLER(wait_debug_event)
 440 {
 441     if (!wait_for_debug_event( req->timeout ))
 442     {
 443         req->event.code = 0;
 444         req->pid = NULL;
 445         req->tid = NULL;
 446     }
 447 }
 448
 449 /* Continue a debug event */
 450 DECL_HANDLER(continue_debug_event)
 451 {
 452     struct process *process = get_process_from_id( req->pid );
 453     if (process)
 454     {
 455         struct thread *thread = get_thread_from_id( req->tid );
 456         if (thread)
 457         {
 458             continue_debug_event( process, thread, req->status );
 459             release_object( thread );
 460         }
 461         release_object( process );
 462     }
 463 }
 464
 465 /* Start debugging an existing process */
 466 DECL_HANDLER(debug_process)
 467 {
 468     struct process *process = get_process_from_id( req->pid );
 469     if (process)
 470     {
 471         debugger_attach( process, current );
 472         /* FIXME: should notify the debugged process somehow */
 473         release_object( process );
 474     }
 475 }
 476
 477 /* Send a debug event */
 478 DECL_HANDLER(send_debug_event)
 479 {
 480     struct thread *debugger = current->process->debugger;
 481     struct debug_event *event;
 482
 483     if ((req->event.code <= 0) || (req->event.code > RIP_EVENT))
 484     {
 485         fatal_protocol_error( current, "send_debug_event: bad code %d\n", req->event.code );
 486         return;
 487     }
 488     req->status = 0;
 489     if (debugger && ((event = queue_debug_event( debugger, current, &req->event ))))
 490     {
 491         /* wait for continue_debug_event */
 492         struct object *obj = &event->obj;
 493         sleep_on( 1, &obj, 0, -1, build_send_event_reply );
 494         release_object( event );
 495     }
 496 }