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