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 };
  40
  41
  42 static void debug_event_dump( struct object *obj, int verbose );
  43 static int debug_event_signaled( struct object *obj, struct thread *thread );
  44 static void debug_event_destroy( struct object *obj );
  45
  46 static const struct object_ops debug_event_ops =
  47 {
  48     sizeof(struct debug_event),    /* size */
  49     debug_event_dump,              /* dump */
  50     add_queue,                     /* add_queue */
  51     remove_queue,                  /* remove_queue */
  52     debug_event_signaled,          /* signaled */
  53     no_satisfied,                  /* satisfied */
  54     NULL,                          /* get_poll_events */
  55     NULL,                          /* poll_event */
  56     no_get_fd,                     /* get_fd */
  57     no_flush,                      /* flush */
  58     no_get_file_info,              /* get_file_info */
  59     debug_event_destroy            /* destroy */
  60 };
  61
  62 static void debug_ctx_dump( struct object *obj, int verbose );
  63 static int debug_ctx_signaled( struct object *obj, struct thread *thread );
  64 static void debug_ctx_destroy( struct object *obj );
  65
  66 static const struct object_ops debug_ctx_ops =
  67 {
  68     sizeof(struct debug_ctx),      /* size */
  69     debug_ctx_dump,                /* dump */
  70     add_queue,                     /* add_queue */
  71     remove_queue,                  /* remove_queue */
  72     debug_ctx_signaled,            /* signaled */
  73     no_satisfied,                  /* satisfied */
  74     NULL,                          /* get_poll_events */
  75     NULL,                          /* poll_event */
  76     no_get_fd,                     /* get_fd */
  77     no_flush,                      /* flush */
  78     no_get_file_info,              /* get_file_info */
  79     debug_ctx_destroy              /* destroy */
  80 };
  81
  82
  83 /* routines to build an event according to its type */
  84
  85 static int fill_exception_event( struct debug_event *event, void *arg )
  86 {
  87     memcpy( &event->data.info.exception, arg, sizeof(event->data.info.exception) );
  88     return 1;
  89 }
  90
  91 static int fill_create_thread_event( struct debug_event *event, void *arg )
  92 {
  93     struct process *debugger = event->debugger->process;
  94     struct thread *thread = event->sender;
  95     handle_t handle;
  96
  97     /* documented: THREAD_GET_CONTEXT | THREAD_SET_CONTEXT | THREAD_SUSPEND_RESUME */
  98     if (!(handle = alloc_handle( debugger, thread, THREAD_ALL_ACCESS, FALSE ))) return 0;
  99     event->data.info.create_thread.handle = handle;
 100     event->data.info.create_thread.teb    = thread->teb;
 101     event->data.info.create_thread.start  = arg;
 102     return 1;
 103 }
 104
 105 static int fill_create_process_event( struct debug_event *event, void *arg )
 106 {
 107     struct process *debugger = event->debugger->process;
 108     struct thread *thread = event->sender;
 109     struct process *process = thread->process;
 110     handle_t handle;
 111
 112     /* documented: PROCESS_VM_READ | PROCESS_VM_WRITE */
 113     if (!(handle = alloc_handle( debugger, process, PROCESS_ALL_ACCESS, FALSE ))) return 0;
 114     event->data.info.create_process.process = handle;
 115
 116     /* documented: THREAD_GET_CONTEXT | THREAD_SET_CONTEXT | THREAD_SUSPEND_RESUME */
 117     if (!(handle = alloc_handle( debugger, thread, THREAD_ALL_ACCESS, FALSE )))
 118     {
 119         close_handle( debugger, event->data.info.create_process.process, NULL );
 120         return 0;
 121     }
 122     event->data.info.create_process.thread = handle;
 123
 124     handle = 0;
 125     if (process->exe.file &&
 126         /* the doc says write access too, but this doesn't seem a good idea */
 127         !(handle = alloc_handle( debugger, process->exe.file, GENERIC_READ, FALSE )))
 128     {
 129         close_handle( debugger, event->data.info.create_process.process, NULL );
 130         close_handle( debugger, event->data.info.create_process.thread, NULL );
 131         return 0;
 132     }
 133     event->data.info.create_process.file       = handle;
 134     event->data.info.create_process.teb        = thread->teb;
 135     event->data.info.create_process.base       = process->exe.base;
 136     event->data.info.create_process.start      = arg;
 137     event->data.info.create_process.dbg_offset = process->exe.dbg_offset;
 138     event->data.info.create_process.dbg_size   = process->exe.dbg_size;
 139     event->data.info.create_process.name       = process->exe.name;
 140     event->data.info.create_process.unicode    = 0;
 141     return 1;
 142 }
 143
 144 static int fill_exit_thread_event( struct debug_event *event, void *arg )
 145 {
 146     struct thread *thread = arg;
 147     event->data.info.exit.exit_code = thread->exit_code;
 148     return 1;
 149 }
 150
 151 static int fill_exit_process_event( struct debug_event *event, void *arg )
 152 {
 153     struct process *process = arg;
 154     event->data.info.exit.exit_code = process->exit_code;
 155     return 1;
 156 }
 157
 158 static int fill_load_dll_event( struct debug_event *event, void *arg )
 159 {
 160     struct process *debugger = event->debugger->process;
 161     struct process_dll *dll = arg;
 162     handle_t handle = 0;
 163
 164     if (dll->file && !(handle = alloc_handle( debugger, dll->file, GENERIC_READ, FALSE )))
 165         return 0;
 166     event->data.info.load_dll.handle     = handle;
 167     event->data.info.load_dll.base       = dll->base;
 168     event->data.info.load_dll.dbg_offset = dll->dbg_offset;
 169     event->data.info.load_dll.dbg_size   = dll->dbg_size;
 170     event->data.info.load_dll.name       = dll->name;
 171     event->data.info.load_dll.unicode    = 0;
 172     return 1;
 173 }
 174
 175 static int fill_unload_dll_event( struct debug_event *event, void *arg )
 176 {
 177     event->data.info.unload_dll.base = arg;
 178     return 1;
 179 }
 180
 181 static int fill_output_debug_string_event( struct debug_event *event, void *arg )
 182 {
 183     struct output_debug_string_request *req = arg;
 184     event->data.info.output_string.string  = req->string;
 185     event->data.info.output_string.unicode = req->unicode;
 186     event->data.info.output_string.length  = req->length;
 187     return 1;
 188 }
 189
 190 typedef int (*fill_event_func)( struct debug_event *event, void *arg );
 191
 192 #define NB_DEBUG_EVENTS OUTPUT_DEBUG_STRING_EVENT  /* RIP_EVENT not supported */
 193
 194 static const fill_event_func fill_debug_event[NB_DEBUG_EVENTS] =
 195 {
 196     fill_exception_event,            /* EXCEPTION_DEBUG_EVENT */
 197     fill_create_thread_event,        /* CREATE_THREAD_DEBUG_EVENT */
 198     fill_create_process_event,       /* CREATE_PROCESS_DEBUG_EVENT */
 199     fill_exit_thread_event,          /* EXIT_THREAD_DEBUG_EVENT */
 200     fill_exit_process_event,         /* EXIT_PROCESS_DEBUG_EVENT */
 201     fill_load_dll_event,             /* LOAD_DLL_DEBUG_EVENT */
 202     fill_unload_dll_event,           /* UNLOAD_DLL_DEBUG_EVENT */
 203     fill_output_debug_string_event   /* OUTPUT_DEBUG_STRING_EVENT */
 204 };
 205
 206
 207 /* unlink the first event from the queue */
 208 static void unlink_event( struct debug_ctx *debug_ctx, struct debug_event *event )
 209 {
 210     if (event->prev) event->prev->next = event->next;
 211     else debug_ctx->event_head = event->next;
 212     if (event->next) event->next->prev = event->prev;
 213     else debug_ctx->event_tail = event->prev;
 214     event->next = event->prev = NULL;
 215     if (event->sender->debug_event == event) event->sender->debug_event = NULL;
 216     release_object( event );
 217 }
 218
 219 /* link an event at the end of the queue */
 220 static void link_event( struct debug_ctx *debug_ctx, struct debug_event *event )
 221 {
 222     grab_object( event );
 223     event->next = NULL;
 224     event->prev = debug_ctx->event_tail;
 225     debug_ctx->event_tail = event;
 226     if (event->prev) event->prev->next = event;
 227     else debug_ctx->event_head = event;
 228     if (!event->sender->debug_event) wake_up( &debug_ctx->obj, 0 );
 229 }
 230
 231 /* find the next event that we can send to the debugger */
 232 static struct debug_event *find_event_to_send( struct debug_ctx *debug_ctx )
 233 {
 234     struct debug_event *event;
 235     for (event = debug_ctx->event_head; event; event = event->next)
 236     {
 237         if (event->state == EVENT_SENT) continue;  /* already sent */
 238         if (event->sender->debug_event) continue;  /* thread busy with another one */
 239         break;
 240     }
 241     return event;
 242 }
 243
 244 /* build a reply for the send_event request */
 245 static void build_exception_event_reply( struct thread *thread, struct object *obj, int signaled )
 246 {
 247     struct exception_event_request *req = get_req_ptr( thread );
 248     struct debug_event *event = (struct debug_event *)obj;
 249     assert( obj->ops == &debug_event_ops );
 250     req->status = event->status;
 251     thread->context = NULL;
 252 }
 253
 254 static void debug_event_dump( struct object *obj, int verbose )
 255 {
 256     struct debug_event *debug_event = (struct debug_event *)obj;
 257     assert( obj->ops == &debug_event_ops );
 258     fprintf( stderr, "Debug event sender=%p code=%d state=%d\n",
 259              debug_event->sender, debug_event->data.code, debug_event->state );
 260 }
 261
 262 static int debug_event_signaled( struct object *obj, struct thread *thread )
 263 {
 264     struct debug_event *debug_event = (struct debug_event *)obj;
 265     assert( obj->ops == &debug_event_ops );
 266     return debug_event->state == EVENT_CONTINUED;
 267 }
 268
 269 static void debug_event_destroy( struct object *obj )
 270 {
 271     struct debug_event *event = (struct debug_event *)obj;
 272     assert( obj->ops == &debug_event_ops );
 273
 274     /* cannot still be in the queue */
 275     assert( !event->next );
 276     assert( !event->prev );
 277
 278     /* If the event has been sent already, the handles are now under the */
 279     /* responsibility of the debugger process, so we don't touch them    */
 280     if (event->state == EVENT_QUEUED)
 281     {
 282         struct process *debugger = event->debugger->process;
 283         switch(event->data.code)
 284         {
 285         case CREATE_THREAD_DEBUG_EVENT:
 286             close_handle( debugger, event->data.info.create_thread.handle, NULL );
 287             break;
 288         case CREATE_PROCESS_DEBUG_EVENT:
 289             if (event->data.info.create_process.file)
 290                 close_handle( debugger, event->data.info.create_process.file, NULL );
 291             close_handle( debugger, event->data.info.create_process.thread, NULL );
 292             close_handle( debugger, event->data.info.create_process.process, NULL );
 293             break;
 294         case LOAD_DLL_DEBUG_EVENT:
 295             if (event->data.info.load_dll.handle)
 296                 close_handle( debugger, event->data.info.load_dll.handle, NULL );
 297             break;
 298         }
 299     }
 300     release_object( event->sender );
 301     release_object( event->debugger );
 302 }
 303
 304 static void debug_ctx_dump( struct object *obj, int verbose )
 305 {
 306     struct debug_ctx *debug_ctx = (struct debug_ctx *)obj;
 307     assert( obj->ops == &debug_ctx_ops );
 308     fprintf( stderr, "Debug context head=%p tail=%p\n",
 309              debug_ctx->event_head, debug_ctx->event_tail );
 310 }
 311
 312 static int debug_ctx_signaled( struct object *obj, struct thread *thread )
 313 {
 314     struct debug_ctx *debug_ctx = (struct debug_ctx *)obj;
 315     assert( obj->ops == &debug_ctx_ops );
 316     return find_event_to_send( debug_ctx ) != NULL;
 317 }
 318
 319 static void debug_ctx_destroy( struct object *obj )
 320 {
 321     struct debug_event *event;
 322     struct debug_ctx *debug_ctx = (struct debug_ctx *)obj;
 323     assert( obj->ops == &debug_ctx_ops );
 324
 325     /* free all pending events */
 326     while ((event = debug_ctx->event_head) != NULL) unlink_event( debug_ctx, event );
 327 }
 328
 329 /* continue a debug event */
 330 static int continue_debug_event( struct process *process, struct thread *thread, int status )
 331 {
 332     struct debug_event *event;
 333     struct debug_ctx *debug_ctx = current->debug_ctx;
 334
 335     if (!debug_ctx || process->debugger != current || thread->process != process) goto error;
 336
 337     /* find the event in the queue */
 338     for (event = debug_ctx->event_head; event; event = event->next)
 339     {
 340         if (event->state != EVENT_SENT) continue;
 341         if (event->sender == thread) break;
 342     }
 343     if (!event) goto error;
 344
 345     assert( event->sender->debug_event == event );
 346
 347     event->status = status;
 348     event->state  = EVENT_CONTINUED;
 349     wake_up( &event->obj, 0 );
 350
 351     unlink_event( debug_ctx, event );
 352     resume_process( process );
 353     return 1;
 354  error:
 355     /* not debugging this process, or no such event */
 356     set_error( STATUS_ACCESS_DENIED );  /* FIXME */
 357     return 0;
 358 }
 359
 360 /* queue a debug event for a debugger */
 361 static struct debug_event *queue_debug_event( struct thread *thread, int code, void *arg )
 362 {
 363     struct thread *debugger = thread->process->debugger;
 364     struct debug_ctx *debug_ctx = debugger->debug_ctx;
 365     struct debug_event *event;
 366
 367     assert( code > 0 && code <= NB_DEBUG_EVENTS );
 368     assert( debug_ctx );
 369     /* cannot queue a debug event for myself */
 370     assert( debugger->process != thread->process );
 371
 372     /* build the event */
 373     if (!(event = alloc_object( &debug_event_ops, -1 ))) return NULL;
 374     event->next      = NULL;
 375     event->prev      = NULL;
 376     event->state     = EVENT_QUEUED;
 377     event->sender    = (struct thread *)grab_object( thread );
 378     event->debugger  = (struct thread *)grab_object( debugger );
 379     event->data.code = code;
 380
 381     if (!fill_debug_event[code-1]( event, arg ))
 382     {
 383         event->data.code = -1;  /* make sure we don't attempt to close handles */
 384         release_object( event );
 385         return NULL;
 386     }
 387
 388     link_event( debug_ctx, event );
 389     suspend_process( thread->process );
 390     return event;
 391 }
 392
 393 /* generate a debug event from inside the server and queue it */
 394 void generate_debug_event( struct thread *thread, int code, void *arg )
 395 {
 396     if (thread->process->debugger)
 397     {
 398         struct debug_event *event = queue_debug_event( thread, code, arg );
 399         if (event) release_object( event );
 400     }
 401 }
 402
 403 /* attach a process to a debugger thread and suspend it */
 404 static int debugger_attach( struct process *process, struct thread *debugger )
 405 {
 406     struct thread *thread;
 407
 408     if (process->debugger) goto error;  /* already being debugged */
 409     if (process->init_event) goto error;  /* still starting up */
 410
 411     /* make sure we don't create a debugging loop */
 412     for (thread = debugger; thread; thread = thread->process->debugger)
 413         if (thread->process == process) goto error;
 414
 415     suspend_process( process );
 416
 417     /* we must have been able to attach all threads */
 418     for (thread = process->thread_list; thread; thread = thread->proc_next)
 419         if (!thread->attached)
 420         {
 421             fprintf( stderr, "%p not attached\n", thread );
 422             resume_process( process );
 423             goto error;
 424         }
 425
 426     if (set_process_debugger( process, debugger )) return 1;
 427     resume_process( process );
 428     return 0;
 429
 430  error:
 431     set_error( STATUS_ACCESS_DENIED );
 432     return 0;
 433 }
 434
 435 /* generate all startup events of a given process */
 436 void generate_startup_debug_events( struct process *process, void *entry )
 437 {
 438     struct process_dll *dll;
 439     struct thread *thread = process->thread_list;
 440
 441     /* generate creation events */
 442     generate_debug_event( thread, CREATE_PROCESS_DEBUG_EVENT, entry );
 443     while ((thread = thread->proc_next))
 444         generate_debug_event( thread, CREATE_THREAD_DEBUG_EVENT, NULL );
 445
 446     /* generate dll events (in loading order, i.e. reverse list order) */
 447     for (dll = &process->exe; dll->next; dll = dll->next);
 448     while (dll != &process->exe)
 449     {
 450         generate_debug_event( process->thread_list, LOAD_DLL_DEBUG_EVENT, dll );
 451         dll = dll->prev;
 452     }
 453 }
 454
 455 /* set the debugger of a given process */
 456 int set_process_debugger( struct process *process, struct thread *debugger )
 457 {
 458     struct debug_ctx *debug_ctx;
 459
 460     assert( !process->debugger );
 461
 462     if (!debugger->debug_ctx)  /* need to allocate a context */
 463     {
 464         if (!(debug_ctx = alloc_object( &debug_ctx_ops, -1 ))) return 0;
 465         debug_ctx->event_head = NULL;
 466         debug_ctx->event_tail = NULL;
 467         debugger->debug_ctx = debug_ctx;
 468     }
 469     process->debugger = debugger;
 470     return 1;
 471 }
 472
 473 /* a thread is exiting */
 474 void debug_exit_thread( struct thread *thread )
 475 {
 476     if (thread->debug_ctx)  /* this thread is a debugger */
 477     {
 478         /* kill all debugged processes */
 479         kill_debugged_processes( thread, thread->exit_code );
 480         release_object( thread->debug_ctx );
 481         thread->debug_ctx = NULL;
 482     }
 483 }
 484
 485 /* Wait for a debug event */
 486 DECL_HANDLER(wait_debug_event)
 487 {
 488     struct debug_ctx *debug_ctx = current->debug_ctx;
 489     struct debug_event *event;
 490
 491     if (!debug_ctx)  /* current thread is not a debugger */
 492     {
 493         set_error( STATUS_INVALID_HANDLE );
 494         return;
 495     }
 496     req->wait = 0;
 497     if ((event = find_event_to_send( debug_ctx )))
 498     {
 499         size_t size = get_req_data_size(req);
 500         event->state = EVENT_SENT;
 501         event->sender->debug_event = event;
 502         req->pid = event->sender->process;
 503         req->tid = event->sender;
 504         if (size > sizeof(debug_event_t)) size = sizeof(debug_event_t);
 505         memcpy( get_req_data(req), &event->data, size );
 506         set_req_data_size( req, size );
 507     }
 508     else  /* no event ready */
 509     {
 510         req->pid  = 0;
 511         req->tid  = 0;
 512         set_req_data_size( req, 0 );
 513         if (req->get_handle)
 514             req->wait = alloc_handle( current->process, debug_ctx, SYNCHRONIZE, FALSE );
 515     }
 516 }
 517
 518 /* Continue a debug event */
 519 DECL_HANDLER(continue_debug_event)
 520 {
 521     struct process *process = get_process_from_id( req->pid );
 522     if (process)
 523     {
 524         struct thread *thread = get_thread_from_id( req->tid );
 525         if (thread)
 526         {
 527             continue_debug_event( process, thread, req->status );
 528             release_object( thread );
 529         }
 530         release_object( process );
 531     }
 532 }
 533
 534 /* Start debugging an existing process */
 535 DECL_HANDLER(debug_process)
 536 {
 537     struct debug_event_exception data;
 538     struct debug_event *event;
 539     struct process *process = get_process_from_id( req->pid );
 540     if (!process) return;
 541
 542     if (debugger_attach( process, current ))
 543     {
 544         generate_startup_debug_events( process, NULL );
 545         resume_process( process );
 546
 547         data.record.ExceptionCode    = EXCEPTION_BREAKPOINT;
 548         data.record.ExceptionFlags   = EXCEPTION_CONTINUABLE;
 549         data.record.ExceptionRecord  = NULL;
 550         data.record.ExceptionAddress = get_thread_ip( process->thread_list );
 551         data.record.NumberParameters = 0;
 552         data.first = 1;
 553         if ((event = queue_debug_event( process->thread_list, EXCEPTION_DEBUG_EVENT, &data )))
 554             release_object( event );
 555     }
 556     release_object( process );
 557 }
 558
 559 /* send an exception event */
 560 DECL_HANDLER(exception_event)
 561 {
 562     req->status = 0;
 563     if (current->process->debugger)
 564     {
 565         struct debug_event_exception data;
 566         struct debug_event *event;
 567         CONTEXT *context = get_req_data( req );
 568         EXCEPTION_RECORD *rec = (EXCEPTION_RECORD *)(context + 1);
 569
 570         if (get_req_data_size( req ) < sizeof(*rec) + sizeof(*context))
 571         {
 572             set_error( STATUS_INVALID_PARAMETER );
 573             return;
 574         }
 575         data.record = *rec;
 576         data.first  = req->first;
 577         if ((event = queue_debug_event( current, EXCEPTION_DEBUG_EVENT, &data )))
 578         {
 579             struct object *obj = &event->obj;
 580             current->context = context;
 581             sleep_on( 1, &obj, 0, 0, 0, build_exception_event_reply );
 582             release_object( event );
 583         }
 584     }
 585 }
 586
 587 /* send an output string to the debugger */
 588 DECL_HANDLER(output_debug_string)
 589 {
 590     if (current->process->debugger)
 591     {
 592         struct debug_event *event = queue_debug_event( current, OUTPUT_DEBUG_STRING_EVENT, req );
 593         if (event) release_object( event );
 594     }
 595 }