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     CONTEXT                context;   /* register context */
  32 };
  33
  34 /* debug context */
  35 struct debug_ctx
  36 {
  37     struct object        obj;         /* object header */
  38     struct debug_event  *event_head;  /* head of pending events queue */
  39     struct debug_event  *event_tail;  /* tail of pending events queue */
  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_get_fd,                     /* get_fd */
  58     no_flush,                      /* flush */
  59     no_get_file_info,              /* get_file_info */
  60     debug_event_destroy            /* destroy */
  61 };
  62
  63 static void debug_ctx_dump( struct object *obj, int verbose );
  64 static int debug_ctx_signaled( struct object *obj, struct thread *thread );
  65 static void debug_ctx_destroy( struct object *obj );
  66
  67 static const struct object_ops debug_ctx_ops =
  68 {
  69     sizeof(struct debug_ctx),      /* size */
  70     debug_ctx_dump,                /* dump */
  71     add_queue,                     /* add_queue */
  72     remove_queue,                  /* remove_queue */
  73     debug_ctx_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     debug_ctx_destroy              /* destroy */
  81 };
  82
  83
  84 /* routines to build an event according to its type */
  85
  86 static int fill_exception_event( struct debug_event *event, void *arg )
  87 {
  88     memcpy( &event->data.info.exception, arg, sizeof(event->data.info.exception) );
  89     return 1;
  90 }
  91
  92 static int fill_create_thread_event( struct debug_event *event, void *arg )
  93 {
  94     struct process *debugger = event->debugger->process;
  95     struct thread *thread = event->sender;
  96     handle_t handle;
  97
  98     /* documented: THREAD_GET_CONTEXT | THREAD_SET_CONTEXT | THREAD_SUSPEND_RESUME */
  99     if (!(handle = alloc_handle( debugger, thread, THREAD_ALL_ACCESS, FALSE ))) return 0;
 100     event->data.info.create_thread.handle = handle;
 101     event->data.info.create_thread.teb    = thread->teb;
 102     event->data.info.create_thread.start  = arg;
 103     return 1;
 104 }
 105
 106 static int fill_create_process_event( struct debug_event *event, void *arg )
 107 {
 108     struct process *debugger = event->debugger->process;
 109     struct thread *thread = event->sender;
 110     struct process *process = thread->process;
 111     handle_t handle;
 112
 113     /* documented: PROCESS_VM_READ | PROCESS_VM_WRITE */
 114     if (!(handle = alloc_handle( debugger, process, PROCESS_ALL_ACCESS, FALSE ))) return 0;
 115     event->data.info.create_process.process = handle;
 116
 117     /* documented: THREAD_GET_CONTEXT | THREAD_SET_CONTEXT | THREAD_SUSPEND_RESUME */
 118     if (!(handle = alloc_handle( debugger, thread, THREAD_ALL_ACCESS, FALSE )))
 119     {
 120         close_handle( debugger, event->data.info.create_process.process, NULL );
 121         return 0;
 122     }
 123     event->data.info.create_process.thread = handle;
 124
 125     handle = 0;
 126     if (process->exe.file &&
 127         /* the doc says write access too, but this doesn't seem a good idea */
 128         !(handle = alloc_handle( debugger, process->exe.file, GENERIC_READ, FALSE )))
 129     {
 130         close_handle( debugger, event->data.info.create_process.process, NULL );
 131         close_handle( debugger, event->data.info.create_process.thread, NULL );
 132         return 0;
 133     }
 134     event->data.info.create_process.file       = handle;
 135     event->data.info.create_process.teb        = thread->teb;
 136     event->data.info.create_process.base       = process->exe.base;
 137     event->data.info.create_process.start      = arg;
 138     event->data.info.create_process.dbg_offset = process->exe.dbg_offset;
 139     event->data.info.create_process.dbg_size   = process->exe.dbg_size;
 140     event->data.info.create_process.name       = process->exe.name;
 141     event->data.info.create_process.unicode    = 0;
 142     return 1;
 143 }
 144
 145 static int fill_exit_thread_event( struct debug_event *event, void *arg )
 146 {
 147     struct thread *thread = arg;
 148     event->data.info.exit.exit_code = thread->exit_code;
 149     return 1;
 150 }
 151
 152 static int fill_exit_process_event( struct debug_event *event, void *arg )
 153 {
 154     struct process *process = arg;
 155     event->data.info.exit.exit_code = process->exit_code;
 156     return 1;
 157 }
 158
 159 static int fill_load_dll_event( struct debug_event *event, void *arg )
 160 {
 161     struct process *debugger = event->debugger->process;
 162     struct process_dll *dll = arg;
 163     handle_t handle = 0;
 164
 165     if (dll->file && !(handle = alloc_handle( debugger, dll->file, GENERIC_READ, FALSE )))
 166         return 0;
 167     event->data.info.load_dll.handle     = handle;
 168     event->data.info.load_dll.base       = dll->base;
 169     event->data.info.load_dll.dbg_offset = dll->dbg_offset;
 170     event->data.info.load_dll.dbg_size   = dll->dbg_size;
 171     event->data.info.load_dll.name       = dll->name;
 172     event->data.info.load_dll.unicode    = 0;
 173     return 1;
 174 }
 175
 176 static int fill_unload_dll_event( struct debug_event *event, void *arg )
 177 {
 178     event->data.info.unload_dll.base = arg;
 179     return 1;
 180 }
 181
 182 static int fill_output_debug_string_event( struct debug_event *event, void *arg )
 183 {
 184     struct debug_event_output_string *data = arg;
 185     event->data.info.output_string = *data;
 186     return 1;
 187 }
 188
 189 typedef int (*fill_event_func)( struct debug_event *event, void *arg );
 190
 191 #define NB_DEBUG_EVENTS OUTPUT_DEBUG_STRING_EVENT  /* RIP_EVENT not supported */
 192
 193 static const fill_event_func fill_debug_event[NB_DEBUG_EVENTS] =
 194 {
 195     fill_exception_event,            /* EXCEPTION_DEBUG_EVENT */
 196     fill_create_thread_event,        /* CREATE_THREAD_DEBUG_EVENT */
 197     fill_create_process_event,       /* CREATE_PROCESS_DEBUG_EVENT */
 198     fill_exit_thread_event,          /* EXIT_THREAD_DEBUG_EVENT */
 199     fill_exit_process_event,         /* EXIT_PROCESS_DEBUG_EVENT */
 200     fill_load_dll_event,             /* LOAD_DLL_DEBUG_EVENT */
 201     fill_unload_dll_event,           /* UNLOAD_DLL_DEBUG_EVENT */
 202     fill_output_debug_string_event   /* OUTPUT_DEBUG_STRING_EVENT */
 203 };
 204
 205
 206 /* unlink the first event from the queue */
 207 static void unlink_event( struct debug_ctx *debug_ctx, struct debug_event *event )
 208 {
 209     if (event->prev) event->prev->next = event->next;
 210     else debug_ctx->event_head = event->next;
 211     if (event->next) event->next->prev = event->prev;
 212     else debug_ctx->event_tail = event->prev;
 213     event->next = event->prev = NULL;
 214     if (event->sender->debug_event == event) event->sender->debug_event = NULL;
 215     release_object( event );
 216 }
 217
 218 /* link an event at the end of the queue */
 219 static void link_event( struct debug_event *event )
 220 {
 221     struct debug_ctx *debug_ctx = event->debugger->debug_ctx;
 222
 223     assert( debug_ctx );
 224     grab_object( event );
 225     event->next = NULL;
 226     event->prev = debug_ctx->event_tail;
 227     debug_ctx->event_tail = event;
 228     if (event->prev) event->prev->next = event;
 229     else debug_ctx->event_head = event;
 230     if (!event->sender->debug_event) wake_up( &debug_ctx->obj, 0 );
 231 }
 232
 233 /* find the next event that we can send to the debugger */
 234 static struct debug_event *find_event_to_send( struct debug_ctx *debug_ctx )
 235 {
 236     struct debug_event *event;
 237     for (event = debug_ctx->event_head; event; event = event->next)
 238     {
 239         if (event->state == EVENT_SENT) continue;  /* already sent */
 240         if (event->sender->debug_event) continue;  /* thread busy with another one */
 241         break;
 242     }
 243     return event;
 244 }
 245
 246 static void debug_event_dump( struct object *obj, int verbose )
 247 {
 248     struct debug_event *debug_event = (struct debug_event *)obj;
 249     assert( obj->ops == &debug_event_ops );
 250     fprintf( stderr, "Debug event sender=%p code=%d state=%d\n",
 251              debug_event->sender, debug_event->data.code, debug_event->state );
 252 }
 253
 254 static int debug_event_signaled( struct object *obj, struct thread *thread )
 255 {
 256     struct debug_event *debug_event = (struct debug_event *)obj;
 257     assert( obj->ops == &debug_event_ops );
 258     return debug_event->state == EVENT_CONTINUED;
 259 }
 260
 261 static void debug_event_destroy( struct object *obj )
 262 {
 263     struct debug_event *event = (struct debug_event *)obj;
 264     assert( obj->ops == &debug_event_ops );
 265
 266     /* cannot still be in the queue */
 267     assert( !event->next );
 268     assert( !event->prev );
 269
 270     /* If the event has been sent already, the handles are now under the */
 271     /* responsibility of the debugger process, so we don't touch them    */
 272     if (event->state == EVENT_QUEUED)
 273     {
 274         struct process *debugger = event->debugger->process;
 275         switch(event->data.code)
 276         {
 277         case CREATE_THREAD_DEBUG_EVENT:
 278             close_handle( debugger, event->data.info.create_thread.handle, NULL );
 279             break;
 280         case CREATE_PROCESS_DEBUG_EVENT:
 281             if (event->data.info.create_process.file)
 282                 close_handle( debugger, event->data.info.create_process.file, NULL );
 283             close_handle( debugger, event->data.info.create_process.thread, NULL );
 284             close_handle( debugger, event->data.info.create_process.process, NULL );
 285             break;
 286         case LOAD_DLL_DEBUG_EVENT:
 287             if (event->data.info.load_dll.handle)
 288                 close_handle( debugger, event->data.info.load_dll.handle, NULL );
 289             break;
 290         }
 291     }
 292     if (event->sender->context == &event->context) event->sender->context = NULL;
 293     release_object( event->sender );
 294     release_object( event->debugger );
 295 }
 296
 297 static void debug_ctx_dump( struct object *obj, int verbose )
 298 {
 299     struct debug_ctx *debug_ctx = (struct debug_ctx *)obj;
 300     assert( obj->ops == &debug_ctx_ops );
 301     fprintf( stderr, "Debug context head=%p tail=%p\n",
 302              debug_ctx->event_head, debug_ctx->event_tail );
 303 }
 304
 305 static int debug_ctx_signaled( struct object *obj, struct thread *thread )
 306 {
 307     struct debug_ctx *debug_ctx = (struct debug_ctx *)obj;
 308     assert( obj->ops == &debug_ctx_ops );
 309     return find_event_to_send( debug_ctx ) != NULL;
 310 }
 311
 312 static void debug_ctx_destroy( struct object *obj )
 313 {
 314     struct debug_event *event;
 315     struct debug_ctx *debug_ctx = (struct debug_ctx *)obj;
 316     assert( obj->ops == &debug_ctx_ops );
 317
 318     /* free all pending events */
 319     while ((event = debug_ctx->event_head) != NULL) unlink_event( debug_ctx, event );
 320 }
 321
 322 /* continue a debug event */
 323 static int continue_debug_event( struct process *process, struct thread *thread, int status )
 324 {
 325     struct debug_event *event;
 326     struct debug_ctx *debug_ctx = current->debug_ctx;
 327
 328     if (!debug_ctx || process->debugger != current || thread->process != process) goto error;
 329
 330     /* find the event in the queue */
 331     for (event = debug_ctx->event_head; event; event = event->next)
 332     {
 333         if (event->state != EVENT_SENT) continue;
 334         if (event->sender == thread) break;
 335     }
 336     if (!event) goto error;
 337
 338     assert( event->sender->debug_event == event );
 339
 340     event->status = status;
 341     event->state  = EVENT_CONTINUED;
 342     wake_up( &event->obj, 0 );
 343
 344     unlink_event( debug_ctx, event );
 345     resume_process( process );
 346     return 1;
 347  error:
 348     /* not debugging this process, or no such event */
 349     set_error( STATUS_ACCESS_DENIED );  /* FIXME */
 350     return 0;
 351 }
 352
 353 /* alloc a debug event for a debugger */
 354 static struct debug_event *alloc_debug_event( struct thread *thread, int code,
 355                                               void *arg, CONTEXT *context )
 356 {
 357     struct thread *debugger = thread->process->debugger;
 358     struct debug_event *event;
 359
 360     assert( code > 0 && code <= NB_DEBUG_EVENTS );
 361     /* cannot queue a debug event for myself */
 362     assert( debugger->process != thread->process );
 363
 364     /* build the event */
 365     if (!(event = alloc_object( &debug_event_ops, -1 ))) return NULL;
 366     event->next      = NULL;
 367     event->prev      = NULL;
 368     event->state     = EVENT_QUEUED;
 369     event->sender    = (struct thread *)grab_object( thread );
 370     event->debugger  = (struct thread *)grab_object( debugger );
 371     event->data.code = code;
 372
 373     if (!fill_debug_event[code-1]( event, arg ))
 374     {
 375         event->data.code = -1;  /* make sure we don't attempt to close handles */
 376         release_object( event );
 377         return NULL;
 378     }
 379     if (context)
 380     {
 381         memcpy( &event->context, context, sizeof(event->context) );
 382         thread->context = &event->context;
 383     }
 384     return event;
 385 }
 386
 387 /* generate a debug event from inside the server and queue it */
 388 void generate_debug_event( struct thread *thread, int code, void *arg )
 389 {
 390     if (thread->process->debugger)
 391     {
 392         struct debug_event *event = alloc_debug_event( thread, code, arg, NULL );
 393         if (event)
 394         {
 395             link_event( event );
 396             suspend_process( thread->process );
 397             release_object( event );
 398         }
 399     }
 400 }
 401
 402 /* attach a process to a debugger thread and suspend it */
 403 static int debugger_attach( struct process *process, struct thread *debugger )
 404 {
 405     struct thread *thread;
 406
 407     if (process->debugger) goto error;  /* already being debugged */
 408     if (process->init_event) goto error;  /* still starting up */
 409
 410     /* make sure we don't create a debugging loop */
 411     for (thread = debugger; thread; thread = thread->process->debugger)
 412         if (thread->process == process) goto error;
 413
 414     suspend_process( process );
 415
 416     /* we must have been able to attach all threads */
 417     for (thread = process->thread_list; thread; thread = thread->proc_next)
 418         if (!thread->attached)
 419         {
 420             fprintf( stderr, "%p not attached\n", thread );
 421             resume_process( process );
 422             goto error;
 423         }
 424
 425     if (set_process_debugger( process, debugger )) return 1;
 426     resume_process( process );
 427     return 0;
 428
 429  error:
 430     set_error( STATUS_ACCESS_DENIED );
 431     return 0;
 432 }
 433
 434 /* generate all startup events of a given process */
 435 void generate_startup_debug_events( struct process *process, void *entry )
 436 {
 437     struct process_dll *dll;
 438     struct thread *thread = process->thread_list;
 439
 440     /* generate creation events */
 441     generate_debug_event( thread, CREATE_PROCESS_DEBUG_EVENT, entry );
 442     while ((thread = thread->proc_next))
 443         generate_debug_event( thread, CREATE_THREAD_DEBUG_EVENT, NULL );
 444
 445     /* generate dll events (in loading order, i.e. reverse list order) */
 446     for (dll = &process->exe; dll->next; dll = dll->next);
 447     while (dll != &process->exe)
 448     {
 449         generate_debug_event( process->thread_list, LOAD_DLL_DEBUG_EVENT, dll );
 450         dll = dll->prev;
 451     }
 452 }
 453
 454 /* set the debugger of a given process */
 455 int set_process_debugger( struct process *process, struct thread *debugger )
 456 {
 457     struct debug_ctx *debug_ctx;
 458
 459     assert( !process->debugger );
 460
 461     if (!debugger->debug_ctx)  /* need to allocate a context */
 462     {
 463         if (!(debug_ctx = alloc_object( &debug_ctx_ops, -1 ))) return 0;
 464         debug_ctx->event_head = NULL;
 465         debug_ctx->event_tail = NULL;
 466         debugger->debug_ctx = debug_ctx;
 467     }
 468     process->debugger = debugger;
 469     return 1;
 470 }
 471
 472 /* a thread is exiting */
 473 void debug_exit_thread( struct thread *thread )
 474 {
 475     if (thread->debug_ctx)  /* this thread is a debugger */
 476     {
 477         /* kill all debugged processes */
 478         kill_debugged_processes( thread, thread->exit_code );
 479         release_object( thread->debug_ctx );
 480         thread->debug_ctx = NULL;
 481     }
 482 }
 483
 484 /* Wait for a debug event */
 485 DECL_HANDLER(wait_debug_event)
 486 {
 487     struct debug_ctx *debug_ctx = current->debug_ctx;
 488     struct debug_event *event;
 489
 490     if (!debug_ctx)  /* current thread is not a debugger */
 491     {
 492         set_error( STATUS_INVALID_HANDLE );
 493         return;
 494     }
 495     req->wait = 0;
 496     if ((event = find_event_to_send( debug_ctx )))
 497     {
 498         size_t size = get_req_data_size(req);
 499         event->state = EVENT_SENT;
 500         event->sender->debug_event = event;
 501         req->pid = event->sender->process;
 502         req->tid = event->sender;
 503         if (size > sizeof(debug_event_t)) size = sizeof(debug_event_t);
 504         memcpy( get_req_data(req), &event->data, size );
 505         set_req_data_size( req, size );
 506     }
 507     else  /* no event ready */
 508     {
 509         req->pid  = 0;
 510         req->tid  = 0;
 511         set_req_data_size( req, 0 );
 512         if (req->get_handle)
 513             req->wait = alloc_handle( current->process, debug_ctx, SYNCHRONIZE, FALSE );
 514     }
 515 }
 516
 517 /* Continue a debug event */
 518 DECL_HANDLER(continue_debug_event)
 519 {
 520     struct process *process = get_process_from_id( req->pid );
 521     if (process)
 522     {
 523         struct thread *thread = get_thread_from_id( req->tid );
 524         if (thread)
 525         {
 526             continue_debug_event( process, thread, req->status );
 527             release_object( thread );
 528         }
 529         release_object( process );
 530     }
 531 }
 532
 533 /* Start debugging an existing process */
 534 DECL_HANDLER(debug_process)
 535 {
 536     struct debug_event_exception data;
 537     struct process *process = get_process_from_id( req->pid );
 538     if (!process) return;
 539
 540     if (debugger_attach( process, current ))
 541     {
 542         generate_startup_debug_events( process, NULL );
 543         resume_process( process );
 544
 545         data.record.ExceptionCode    = EXCEPTION_BREAKPOINT;
 546         data.record.ExceptionFlags   = EXCEPTION_CONTINUABLE;
 547         data.record.ExceptionRecord  = NULL;
 548         data.record.ExceptionAddress = get_thread_ip( process->thread_list );
 549         data.record.NumberParameters = 0;
 550         data.first = 1;
 551         generate_debug_event( process->thread_list, EXCEPTION_DEBUG_EVENT, &data );
 552     }
 553     release_object( process );
 554 }
 555
 556 /* queue an exception event */
 557 DECL_HANDLER(queue_exception_event)
 558 {
 559     req->handle = 0;
 560     if (current->process->debugger)
 561     {
 562         struct debug_event_exception data;
 563         struct debug_event *event;
 564         CONTEXT *context = get_req_data( req );
 565         EXCEPTION_RECORD *rec = (EXCEPTION_RECORD *)(context + 1);
 566
 567         if (get_req_data_size( req ) < sizeof(*rec) + sizeof(*context))
 568         {
 569             set_error( STATUS_INVALID_PARAMETER );
 570             return;
 571         }
 572         data.record = *rec;
 573         data.first  = req->first;
 574         if ((event = alloc_debug_event( current, EXCEPTION_DEBUG_EVENT, &data, context )))
 575         {
 576             if ((req->handle = alloc_handle( current->process, event, SYNCHRONIZE, FALSE )))
 577             {
 578                 link_event( event );
 579                 suspend_process( current->process );
 580             }
 581             release_object( event );
 582         }
 583     }
 584 }
 585
 586 /* retrieve the status of an exception event */
 587 DECL_HANDLER(get_exception_status)
 588 {
 589     struct debug_event *event;
 590     size_t size = 0;
 591
 592     req->status = 0;
 593     if ((event = (struct debug_event *)get_handle_obj( current->process, req->handle,
 594                                                        0, &debug_event_ops )))
 595     {
 596         if (event->state == EVENT_CONTINUED)
 597         {
 598             req->status = event->status;
 599             if (current->context == &event->context)
 600             {
 601                 size = min( sizeof(CONTEXT), get_req_data_size(req) );
 602                 memcpy( get_req_data(req), &event->context, size );
 603                 current->context = NULL;
 604             }
 605         }
 606         else set_error( STATUS_PENDING );
 607         release_object( event );
 608     }
 609     set_req_data_size( req, size );
 610 }
 611
 612 /* send an output string to the debugger */
 613 DECL_HANDLER(output_debug_string)
 614 {
 615     struct debug_event_output_string data;
 616
 617     data.string  = req->string;
 618     data.unicode = req->unicode;
 619     data.length  = req->length;
 620     generate_debug_event( current, OUTPUT_DEBUG_STRING_EVENT, &data );
 621 }