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