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 #include "winerror.h"
  13
  14 #include "handle.h"
  15 #include "process.h"
  16 #include "thread.h"
  17 #include "request.h"
  18
  19 enum debug_event_state { EVENT_QUEUED, EVENT_SENT, EVENT_CONTINUED };
  20
  21 /* debug event */
  22 struct debug_event
  23 {
  24     struct object          obj;       /* object header */
  25     struct debug_event    *next;      /* event queue */
  26     struct debug_event    *prev;
  27     struct thread         *sender;    /* thread which sent this event */
  28     struct thread         *debugger;  /* debugger thread receiving the event */
  29     enum debug_event_state state;     /* event state */
  30     int                    status;    /* continuation status */
  31     int                    code;      /* event code */
  32     union debug_event_data data;      /* event data */
  33 };
  34
  35 /* debug context */
  36 struct debug_ctx
  37 {
  38     struct object        obj;         /* object header */
  39     struct debug_event  *event_head;  /* head of pending events queue */
  40     struct debug_event  *event_tail;  /* tail of pending events queue */
  41     struct debug_event  *to_send;     /* next event on the queue to send to debugger */
  42 };
  43
  44
  45 static void debug_event_dump( struct object *obj, int verbose );
  46 static int debug_event_signaled( struct object *obj, struct thread *thread );
  47 static void debug_event_destroy( struct object *obj );
  48
  49 static const struct object_ops debug_event_ops =
  50 {
  51     sizeof(struct debug_event),    /* size */
  52     debug_event_dump,              /* dump */
  53     add_queue,                     /* add_queue */
  54     remove_queue,                  /* remove_queue */
  55     debug_event_signaled,          /* signaled */
  56     no_satisfied,                  /* satisfied */
  57     NULL,                          /* get_poll_events */
  58     NULL,                          /* poll_event */
  59     no_read_fd,                    /* get_read_fd */
  60     no_write_fd,                   /* get_write_fd */
  61     no_flush,                      /* flush */
  62     no_get_file_info,              /* get_file_info */
  63     debug_event_destroy            /* destroy */
  64 };
  65
  66 static void debug_ctx_dump( struct object *obj, int verbose );
  67 static int debug_ctx_signaled( struct object *obj, struct thread *thread );
  68 static void debug_ctx_destroy( struct object *obj );
  69
  70 static const struct object_ops debug_ctx_ops =
  71 {
  72     sizeof(struct debug_ctx),      /* size */
  73     debug_ctx_dump,                /* dump */
  74     add_queue,                     /* add_queue */
  75     remove_queue,                  /* remove_queue */
  76     debug_ctx_signaled,            /* signaled */
  77     no_satisfied,                  /* satisfied */
  78     NULL,                          /* get_poll_events */
  79     NULL,                          /* poll_event */
  80     no_read_fd,                    /* get_read_fd */
  81     no_write_fd,                   /* get_write_fd */
  82     no_flush,                      /* flush */
  83     no_get_file_info,              /* get_file_info */
  84     debug_ctx_destroy              /* destroy */
  85 };
  86
  87 /* size of the event data */
  88 static const int event_sizes[] =
  89 {
  90     0,
  91     sizeof(struct debug_event_exception),       /* EXCEPTION_DEBUG_EVENT */
  92     sizeof(struct debug_event_create_thread),   /* CREATE_THREAD_DEBUG_EVENT */
  93     sizeof(struct debug_event_create_process),  /* CREATE_PROCESS_DEBUG_EVENT */
  94     sizeof(struct debug_event_exit),            /* EXIT_THREAD_DEBUG_EVENT */
  95     sizeof(struct debug_event_exit),            /* EXIT_PROCESS_DEBUG_EVENT */
  96     sizeof(struct debug_event_load_dll),        /* LOAD_DLL_DEBUG_EVENT */
  97     sizeof(struct debug_event_unload_dll),      /* UNLOAD_DLL_DEBUG_EVENT */
  98     sizeof(struct debug_event_output_string),   /* OUTPUT_DEBUG_STRING_EVENT */
  99     sizeof(struct debug_event_rip_info)         /* RIP_EVENT */
 100 };
 101
 102
 103 /* initialise the fields that do not need to be filled by the client */
 104 static int fill_debug_event( struct thread *debugger, struct thread *thread,
 105                              struct debug_event *event )
 106 {
 107     int handle;
 108
 109     /* some events need special handling */
 110     switch(event->code)
 111     {
 112     case CREATE_THREAD_DEBUG_EVENT:
 113         if ((event->data.create_thread.handle = alloc_handle( debugger->process, thread,
 114                /* documented: THREAD_GET_CONTEXT | THREAD_SET_CONTEXT | THREAD_SUSPEND_RESUME */
 115                                                               THREAD_ALL_ACCESS, FALSE )) == -1)
 116             return 0;
 117         break;
 118     case CREATE_PROCESS_DEBUG_EVENT:
 119         if ((handle = event->data.create_process.file) != -1)
 120         {
 121             if ((handle = duplicate_handle( thread->process, handle, debugger->process,
 122                                             GENERIC_READ, FALSE, 0 )) == -1)
 123                 return 0;
 124             event->data.create_process.file = handle;
 125         }
 126         if ((event->data.create_process.process = alloc_handle( debugger->process, thread->process,
 127                                            /* documented: PROCESS_VM_READ | PROCESS_VM_WRITE */
 128                                                                 PROCESS_ALL_ACCESS, FALSE )) == -1)
 129         {
 130             if (handle != -1) close_handle( debugger->process, handle );
 131             return 0;
 132         }
 133         if ((event->data.create_process.thread = alloc_handle( debugger->process, thread,
 134                /* documented: THREAD_GET_CONTEXT | THREAD_SET_CONTEXT | THREAD_SUSPEND_RESUME */
 135                                                                THREAD_ALL_ACCESS, FALSE )) == -1)
 136         {
 137             if (handle != -1) close_handle( debugger->process, handle );
 138             close_handle( debugger->process, event->data.create_process.process );
 139             return 0;
 140         }
 141         break;
 142     case LOAD_DLL_DEBUG_EVENT:
 143         if ((handle = event->data.load_dll.handle) != -1)
 144         {
 145             if ((handle = duplicate_handle( thread->process, handle, debugger->process,
 146                                             GENERIC_READ, FALSE, 0 )) == -1)
 147                 return 0;
 148             event->data.load_dll.handle = handle;
 149         }
 150         break;
 151     }
 152     return 1;
 153 }
 154
 155 /* unlink the first event from the queue */
 156 static void unlink_event( struct debug_ctx *debug_ctx, struct debug_event *event )
 157 {
 158     if (event->prev) event->prev->next = event->next;
 159     else debug_ctx->event_head = event->next;
 160     if (event->next) event->next->prev = event->prev;
 161     else debug_ctx->event_tail = event->prev;
 162     if (debug_ctx->to_send == event) debug_ctx->to_send = event->next;
 163     event->next = event->prev = NULL;
 164     release_object( event );
 165 }
 166
 167 /* link an event at the end of the queue */
 168 static void link_event( struct debug_ctx *debug_ctx, struct debug_event *event )
 169 {
 170     grab_object( event );
 171     event->next = NULL;
 172     event->prev = debug_ctx->event_tail;
 173     debug_ctx->event_tail = event;
 174     if (event->prev) event->prev->next = event;
 175     else debug_ctx->event_head = event;
 176     if (!debug_ctx->to_send)
 177     {
 178         debug_ctx->to_send = event;
 179         wake_up( &debug_ctx->obj, 0 );
 180     }
 181 }
 182
 183 /* build a reply for the wait_debug_event request */
 184 static void build_wait_debug_reply( struct thread *thread, struct object *obj, int signaled )
 185 {
 186     struct wait_debug_event_request *req = get_req_ptr( thread );
 187
 188     if (obj)
 189     {
 190         struct debug_ctx *debug_ctx = (struct debug_ctx *)obj;
 191         struct debug_event *event = debug_ctx->to_send;
 192
 193         /* the object that woke us has to be our debug context */
 194         assert( obj->ops == &debug_ctx_ops );
 195         assert( event );
 196
 197         event->state = EVENT_SENT;
 198         debug_ctx->to_send = event->next;
 199         req->code = event->code;
 200         req->pid  = event->sender->process;
 201         req->tid  = event->sender;
 202         memcpy( req + 1, &event->data, event_sizes[event->code] );
 203     }
 204     else  /* timeout or error */
 205     {
 206         req->code = 0;
 207         req->pid  = 0;
 208         req->tid  = 0;
 209         thread->error = signaled;
 210     }
 211 }
 212
 213 /* build a reply for the send_event request */
 214 static void build_send_event_reply( struct thread *thread, struct object *obj, int signaled )
 215 {
 216     struct send_debug_event_request *req = get_req_ptr( thread );
 217     struct debug_event *event = (struct debug_event *)obj;
 218     assert( obj->ops == &debug_event_ops );
 219
 220     req->status = event->status;
 221     /* copy the context into the reply */
 222     if (event->code == EXCEPTION_DEBUG_EVENT)
 223         memcpy( req + 1, &event->data, event_sizes[event->code] );
 224 }
 225
 226 static void debug_event_dump( struct object *obj, int verbose )
 227 {
 228     struct debug_event *debug_event = (struct debug_event *)obj;
 229     assert( obj->ops == &debug_event_ops );
 230     fprintf( stderr, "Debug event sender=%p code=%d state=%d\n",
 231              debug_event->sender, debug_event->code, debug_event->state );
 232 }
 233
 234 static int debug_event_signaled( struct object *obj, struct thread *thread )
 235 {
 236     struct debug_event *debug_event = (struct debug_event *)obj;
 237     assert( obj->ops == &debug_event_ops );
 238     return debug_event->state == EVENT_CONTINUED;
 239 }
 240
 241 static void debug_event_destroy( struct object *obj )
 242 {
 243     struct debug_event *event = (struct debug_event *)obj;
 244     assert( obj->ops == &debug_event_ops );
 245
 246     /* cannot still be in the queue */
 247     assert( !event->next );
 248     assert( !event->prev );
 249
 250     /* If the event has been sent already, the handles are now under the */
 251     /* responsibility of the debugger process, so we don't touch them    */
 252     if (event->state == EVENT_QUEUED)
 253     {
 254         struct process *debugger = event->debugger->process;
 255         switch(event->code)
 256         {
 257         case CREATE_THREAD_DEBUG_EVENT:
 258             close_handle( debugger, event->data.create_thread.handle );
 259             break;
 260         case CREATE_PROCESS_DEBUG_EVENT:
 261             if (event->data.create_process.file != -1)
 262                 close_handle( debugger, event->data.create_process.file );
 263             close_handle( debugger, event->data.create_process.thread );
 264             close_handle( debugger, event->data.create_process.process );
 265             break;
 266         case LOAD_DLL_DEBUG_EVENT:
 267             if (event->data.load_dll.handle != -1)
 268                 close_handle( debugger, event->data.load_dll.handle );
 269             break;
 270         }
 271     }
 272     release_object( event->sender );
 273     release_object( event->debugger );
 274 }
 275
 276 static void debug_ctx_dump( struct object *obj, int verbose )
 277 {
 278     struct debug_ctx *debug_ctx = (struct debug_ctx *)obj;
 279     assert( obj->ops == &debug_ctx_ops );
 280     fprintf( stderr, "Debug context head=%p tail=%p to_send=%p\n",
 281              debug_ctx->event_head, debug_ctx->event_tail, debug_ctx->to_send );
 282 }
 283
 284 static int debug_ctx_signaled( struct object *obj, struct thread *thread )
 285 {
 286     struct debug_ctx *debug_ctx = (struct debug_ctx *)obj;
 287     assert( obj->ops == &debug_ctx_ops );
 288     return debug_ctx->to_send != NULL;
 289 }
 290
 291 static void debug_ctx_destroy( struct object *obj )
 292 {
 293     struct debug_event *event;
 294     struct debug_ctx *debug_ctx = (struct debug_ctx *)obj;
 295     assert( obj->ops == &debug_ctx_ops );
 296
 297     /* free all pending events */
 298     while ((event = debug_ctx->event_head) != NULL) unlink_event( debug_ctx, event );
 299 }
 300
 301 /* wait for a debug event (or send a reply at once if one is pending) */
 302 static int wait_for_debug_event( int timeout )
 303 {
 304     struct debug_ctx *debug_ctx = current->debug_ctx;
 305     struct object *obj = &debug_ctx->obj;
 306     int flags = 0;
 307
 308     if (!debug_ctx)  /* current thread is not a debugger */
 309     {
 310         set_error( ERROR_INVALID_HANDLE );
 311         return 0;
 312     }
 313     if (timeout != -1) flags = SELECT_TIMEOUT;
 314     return sleep_on( 1, &obj, flags, timeout, build_wait_debug_reply );
 315 }
 316
 317 /* continue a debug event */
 318 static int continue_debug_event( struct process *process, struct thread *thread, int status )
 319 {
 320     struct debug_event *event;
 321     struct debug_ctx *debug_ctx = current->debug_ctx;
 322
 323     if (!debug_ctx || process->debugger != current || thread->process != process) goto error;
 324
 325     /* find the event in the queue */
 326     for (event = debug_ctx->event_head; event; event = event->next)
 327     {
 328         if (event == debug_ctx->to_send) goto error;
 329         if (event->sender == thread) break;
 330         event = event->next;
 331     }
 332     if (!event) goto error;
 333
 334     event->status = status;
 335     event->state  = EVENT_CONTINUED;
 336     wake_up( &event->obj, 0 );
 337
 338     unlink_event( debug_ctx, event );
 339     resume_process( process );
 340     return 1;
 341  error:
 342     /* not debugging this process, or no such event */
 343     set_error( ERROR_ACCESS_DENIED );  /* FIXME */
 344     return 0;
 345 }
 346
 347 /* queue a debug event for a debugger */
 348 static struct debug_event *queue_debug_event( struct thread *debugger, struct thread *thread,
 349                                               int code, void *data )
 350 {
 351     struct debug_ctx *debug_ctx = debugger->debug_ctx;
 352     struct debug_event *event;
 353
 354     assert( debug_ctx );
 355     /* cannot queue a debug event for myself */
 356     assert( debugger->process != thread->process );
 357
 358     /* build the event */
 359     if (!(event = alloc_object( &debug_event_ops, -1 ))) return NULL;
 360     event->next     = NULL;
 361     event->prev     = NULL;
 362     event->state    = EVENT_QUEUED;
 363     event->code     = code;
 364     event->sender   = (struct thread *)grab_object( thread );
 365     event->debugger = (struct thread *)grab_object( debugger );
 366     memcpy( &event->data, data, event_sizes[code] );
 367
 368     if (!fill_debug_event( debugger, thread, event ))
 369     {
 370         event->code = -1;  /* make sure we don't attempt to close handles */
 371         release_object( event );
 372         return NULL;
 373     }
 374
 375     link_event( debug_ctx, event );
 376     suspend_process( thread->process );
 377     return event;
 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( ERROR_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( ERROR_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         struct debug_event_exit exit;
 421         exit.exit_code = exit_code;
 422         if (thread->process->running_threads == 1)
 423             /* this is the last thread, send an exit process event */
 424             event = queue_debug_event( debugger, thread, EXIT_PROCESS_DEBUG_EVENT, &exit );
 425         else
 426             event = queue_debug_event( debugger, thread, EXIT_THREAD_DEBUG_EVENT, &exit );
 427         if (event) release_object( event );
 428     }
 429
 430     if (debug_ctx)  /* this thread is a debugger */
 431     {
 432         /* kill all debugged processes */
 433         kill_debugged_processes( thread, exit_code );
 434         thread->debug_ctx = NULL;
 435         release_object( debug_ctx );
 436     }
 437 }
 438
 439 /* Wait for a debug event */
 440 DECL_HANDLER(wait_debug_event)
 441 {
 442     if (!wait_for_debug_event( req->timeout ))
 443     {
 444         req->code = 0;
 445         req->pid  = NULL;
 446         req->tid  = NULL;
 447     }
 448 }
 449
 450 /* Continue a debug event */
 451 DECL_HANDLER(continue_debug_event)
 452 {
 453     struct process *process = get_process_from_id( req->pid );
 454     if (process)
 455     {
 456         struct thread *thread = get_thread_from_id( req->tid );
 457         if (thread)
 458         {
 459             continue_debug_event( process, thread, req->status );
 460             release_object( thread );
 461         }
 462         release_object( process );
 463     }
 464 }
 465
 466 /* Start debugging an existing process */
 467 DECL_HANDLER(debug_process)
 468 {
 469     struct process *process = get_process_from_id( req->pid );
 470     if (process)
 471     {
 472         debugger_attach( process, current );
 473         /* FIXME: should notify the debugged process somehow */
 474         release_object( process );
 475     }
 476 }
 477
 478 /* Send a debug event */
 479 DECL_HANDLER(send_debug_event)
 480 {
 481     struct thread *debugger = current->process->debugger;
 482     struct debug_event *event;
 483
 484     if ((req->code <= 0) || (req->code > RIP_EVENT))
 485     {
 486         fatal_protocol_error( current, "send_debug_event: bad code %d\n", req->code );
 487         return;
 488     }
 489     req->status = 0;
 490     if (debugger && ((event = queue_debug_event( debugger, current, req->code, req + 1 ))))
 491     {
 492         /* wait for continue_debug_event */
 493         struct object *obj = &event->obj;
 494         sleep_on( 1, &obj, 0, -1, build_send_event_reply );
 495         release_object( event );
 496     }
 497 }