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 wait_debug_event request */
 245 static void build_wait_debug_reply( struct thread *thread, struct object *obj, int signaled )
 246 {
 247     struct wait_debug_event_request *req = get_req_ptr( thread );
 248
 249     if (obj)
 250     {
 251         struct debug_ctx *debug_ctx = (struct debug_ctx *)obj;
 252         struct debug_event *event = find_event_to_send( debug_ctx );
 253         size_t size = get_req_data_size(req);
 254
 255         /* the object that woke us has to be our debug context */
 256         assert( obj->ops == &debug_ctx_ops );
 257         assert( event );
 258
 259         event->state = EVENT_SENT;
 260         event->sender->debug_event = event;
 261         req->pid = event->sender->process;
 262         req->tid = event->sender;
 263         if (size > sizeof(debug_event_t)) size = sizeof(debug_event_t);
 264         memcpy( get_req_data(req), &event->data, size );
 265         set_req_data_size( req, size );
 266     }
 267     else  /* timeout or error */
 268     {
 269         set_req_data_size( req, 0 );
 270         req->pid  = 0;
 271         req->tid  = 0;
 272     }
 273 }
 274
 275 /* build a reply for the send_event request */
 276 static void build_exception_event_reply( struct thread *thread, struct object *obj, int signaled )
 277 {
 278     struct exception_event_request *req = get_req_ptr( thread );
 279     struct debug_event *event = (struct debug_event *)obj;
 280     assert( obj->ops == &debug_event_ops );
 281     req->status = event->status;
 282     thread->context = NULL;
 283 }
 284
 285 static void debug_event_dump( struct object *obj, int verbose )
 286 {
 287     struct debug_event *debug_event = (struct debug_event *)obj;
 288     assert( obj->ops == &debug_event_ops );
 289     fprintf( stderr, "Debug event sender=%p code=%d state=%d\n",
 290              debug_event->sender, debug_event->data.code, debug_event->state );
 291 }
 292
 293 static int debug_event_signaled( struct object *obj, struct thread *thread )
 294 {
 295     struct debug_event *debug_event = (struct debug_event *)obj;
 296     assert( obj->ops == &debug_event_ops );
 297     return debug_event->state == EVENT_CONTINUED;
 298 }
 299
 300 static void debug_event_destroy( struct object *obj )
 301 {
 302     struct debug_event *event = (struct debug_event *)obj;
 303     assert( obj->ops == &debug_event_ops );
 304
 305     /* cannot still be in the queue */
 306     assert( !event->next );
 307     assert( !event->prev );
 308
 309     /* If the event has been sent already, the handles are now under the */
 310     /* responsibility of the debugger process, so we don't touch them    */
 311     if (event->state == EVENT_QUEUED)
 312     {
 313         struct process *debugger = event->debugger->process;
 314         switch(event->data.code)
 315         {
 316         case CREATE_THREAD_DEBUG_EVENT:
 317             close_handle( debugger, event->data.info.create_thread.handle, NULL );
 318             break;
 319         case CREATE_PROCESS_DEBUG_EVENT:
 320             if (event->data.info.create_process.file)
 321                 close_handle( debugger, event->data.info.create_process.file, NULL );
 322             close_handle( debugger, event->data.info.create_process.thread, NULL );
 323             close_handle( debugger, event->data.info.create_process.process, NULL );
 324             break;
 325         case LOAD_DLL_DEBUG_EVENT:
 326             if (event->data.info.load_dll.handle)
 327                 close_handle( debugger, event->data.info.load_dll.handle, NULL );
 328             break;
 329         }
 330     }
 331     release_object( event->sender );
 332     release_object( event->debugger );
 333 }
 334
 335 static void debug_ctx_dump( struct object *obj, int verbose )
 336 {
 337     struct debug_ctx *debug_ctx = (struct debug_ctx *)obj;
 338     assert( obj->ops == &debug_ctx_ops );
 339     fprintf( stderr, "Debug context head=%p tail=%p\n",
 340              debug_ctx->event_head, debug_ctx->event_tail );
 341 }
 342
 343 static int debug_ctx_signaled( struct object *obj, struct thread *thread )
 344 {
 345     struct debug_ctx *debug_ctx = (struct debug_ctx *)obj;
 346     assert( obj->ops == &debug_ctx_ops );
 347     return find_event_to_send( debug_ctx ) != NULL;
 348 }
 349
 350 static void debug_ctx_destroy( struct object *obj )
 351 {
 352     struct debug_event *event;
 353     struct debug_ctx *debug_ctx = (struct debug_ctx *)obj;
 354     assert( obj->ops == &debug_ctx_ops );
 355
 356     /* free all pending events */
 357     while ((event = debug_ctx->event_head) != NULL) unlink_event( debug_ctx, event );
 358 }
 359
 360 /* wait for a debug event (or send a reply at once if one is pending) */
 361 static int wait_for_debug_event( int timeout )
 362 {
 363     struct debug_ctx *debug_ctx = current->debug_ctx;
 364     struct object *obj = &debug_ctx->obj;
 365     int flags = 0;
 366     struct timeval tv;
 367
 368     if (!debug_ctx)  /* current thread is not a debugger */
 369     {
 370         set_error( STATUS_INVALID_HANDLE );
 371         return 0;
 372     }
 373     if (timeout != -1)
 374     {
 375         flags = SELECT_TIMEOUT;
 376         gettimeofday( &tv, 0 );
 377         add_timeout( &tv, timeout );
 378     }
 379     else tv.tv_sec = tv.tv_usec = 0;
 380     return sleep_on( 1, &obj, flags, tv.tv_sec, tv.tv_usec, build_wait_debug_reply );
 381 }
 382
 383 /* continue a debug event */
 384 static int continue_debug_event( struct process *process, struct thread *thread, int status )
 385 {
 386     struct debug_event *event;
 387     struct debug_ctx *debug_ctx = current->debug_ctx;
 388
 389     if (!debug_ctx || process->debugger != current || thread->process != process) goto error;
 390
 391     /* find the event in the queue */
 392     for (event = debug_ctx->event_head; event; event = event->next)
 393     {
 394         if (event->state != EVENT_SENT) continue;
 395         if (event->sender == thread) break;
 396     }
 397     if (!event) goto error;
 398
 399     assert( event->sender->debug_event == event );
 400
 401     event->status = status;
 402     event->state  = EVENT_CONTINUED;
 403     wake_up( &event->obj, 0 );
 404
 405     unlink_event( debug_ctx, event );
 406     resume_process( process );
 407     return 1;
 408  error:
 409     /* not debugging this process, or no such event */
 410     set_error( STATUS_ACCESS_DENIED );  /* FIXME */
 411     return 0;
 412 }
 413
 414 /* queue a debug event for a debugger */
 415 static struct debug_event *queue_debug_event( struct thread *thread, int code, void *arg )
 416 {
 417     struct thread *debugger = thread->process->debugger;
 418     struct debug_ctx *debug_ctx = debugger->debug_ctx;
 419     struct debug_event *event;
 420
 421     assert( code > 0 && code <= NB_DEBUG_EVENTS );
 422     assert( debug_ctx );
 423     /* cannot queue a debug event for myself */
 424     assert( debugger->process != thread->process );
 425
 426     /* build the event */
 427     if (!(event = alloc_object( &debug_event_ops, -1 ))) return NULL;
 428     event->next      = NULL;
 429     event->prev      = NULL;
 430     event->state     = EVENT_QUEUED;
 431     event->sender    = (struct thread *)grab_object( thread );
 432     event->debugger  = (struct thread *)grab_object( debugger );
 433     event->data.code = code;
 434
 435     if (!fill_debug_event[code-1]( event, arg ))
 436     {
 437         event->data.code = -1;  /* make sure we don't attempt to close handles */
 438         release_object( event );
 439         return NULL;
 440     }
 441
 442     link_event( debug_ctx, event );
 443     suspend_process( thread->process );
 444     return event;
 445 }
 446
 447 /* generate a debug event from inside the server and queue it */
 448 void generate_debug_event( struct thread *thread, int code, void *arg )
 449 {
 450     if (thread->process->debugger)
 451     {
 452         struct debug_event *event = queue_debug_event( thread, code, arg );
 453         if (event) release_object( event );
 454     }
 455 }
 456
 457 /* attach a process to a debugger thread and suspend it */
 458 static int debugger_attach( struct process *process, struct thread *debugger )
 459 {
 460     struct thread *thread;
 461
 462     if (process->debugger) goto error;  /* already being debugged */
 463     if (process->init_event) goto error;  /* still starting up */
 464
 465     /* make sure we don't create a debugging loop */
 466     for (thread = debugger; thread; thread = thread->process->debugger)
 467         if (thread->process == process) goto error;
 468
 469     suspend_process( process );
 470
 471     /* we must have been able to attach all threads */
 472     for (thread = process->thread_list; thread; thread = thread->proc_next)
 473         if (!thread->attached)
 474         {
 475             fprintf( stderr, "%p not attached\n", thread );
 476             resume_process( process );
 477             goto error;
 478         }
 479
 480     if (set_process_debugger( process, debugger )) return 1;
 481     resume_process( process );
 482     return 0;
 483
 484  error:
 485     set_error( STATUS_ACCESS_DENIED );
 486     return 0;
 487 }
 488
 489 /* generate all startup events of a given process */
 490 void generate_startup_debug_events( struct process *process, void *entry )
 491 {
 492     struct process_dll *dll;
 493     struct thread *thread = process->thread_list;
 494
 495     /* generate creation events */
 496     generate_debug_event( thread, CREATE_PROCESS_DEBUG_EVENT, entry );
 497     while ((thread = thread->proc_next))
 498         generate_debug_event( thread, CREATE_THREAD_DEBUG_EVENT, NULL );
 499
 500     /* generate dll events (in loading order, i.e. reverse list order) */
 501     for (dll = &process->exe; dll->next; dll = dll->next);
 502     while (dll != &process->exe)
 503     {
 504         generate_debug_event( process->thread_list, LOAD_DLL_DEBUG_EVENT, dll );
 505         dll = dll->prev;
 506     }
 507 }
 508
 509 /* set the debugger of a given process */
 510 int set_process_debugger( struct process *process, struct thread *debugger )
 511 {
 512     struct debug_ctx *debug_ctx;
 513
 514     assert( !process->debugger );
 515
 516     if (!debugger->debug_ctx)  /* need to allocate a context */
 517     {
 518         if (!(debug_ctx = alloc_object( &debug_ctx_ops, -1 ))) return 0;
 519         debug_ctx->event_head = NULL;
 520         debug_ctx->event_tail = NULL;
 521         debugger->debug_ctx = debug_ctx;
 522     }
 523     process->debugger = debugger;
 524     return 1;
 525 }
 526
 527 /* a thread is exiting */
 528 void debug_exit_thread( struct thread *thread )
 529 {
 530     if (thread->debug_ctx)  /* this thread is a debugger */
 531     {
 532         /* kill all debugged processes */
 533         kill_debugged_processes( thread, thread->exit_code );
 534         release_object( thread->debug_ctx );
 535         thread->debug_ctx = NULL;
 536     }
 537 }
 538
 539 /* Wait for a debug event */
 540 DECL_HANDLER(wait_debug_event)
 541 {
 542     if (!wait_for_debug_event( req->timeout ))
 543     {
 544         req->pid = NULL;
 545         req->tid = NULL;
 546         set_req_data_size( req, 0 );
 547     }
 548 }
 549
 550 /* Continue a debug event */
 551 DECL_HANDLER(continue_debug_event)
 552 {
 553     struct process *process = get_process_from_id( req->pid );
 554     if (process)
 555     {
 556         struct thread *thread = get_thread_from_id( req->tid );
 557         if (thread)
 558         {
 559             continue_debug_event( process, thread, req->status );
 560             release_object( thread );
 561         }
 562         release_object( process );
 563     }
 564 }
 565
 566 /* Start debugging an existing process */
 567 DECL_HANDLER(debug_process)
 568 {
 569     struct debug_event_exception data;
 570     struct debug_event *event;
 571     struct process *process = get_process_from_id( req->pid );
 572     if (!process) return;
 573
 574     if (debugger_attach( process, current ))
 575     {
 576         generate_startup_debug_events( process, NULL );
 577         resume_process( process );
 578
 579         data.record.ExceptionCode    = EXCEPTION_BREAKPOINT;
 580         data.record.ExceptionFlags   = EXCEPTION_CONTINUABLE;
 581         data.record.ExceptionRecord  = NULL;
 582         data.record.ExceptionAddress = get_thread_ip( process->thread_list );
 583         data.record.NumberParameters = 0;
 584         data.first = 1;
 585         if ((event = queue_debug_event( process->thread_list, EXCEPTION_DEBUG_EVENT, &data )))
 586             release_object( event );
 587     }
 588     release_object( process );
 589 }
 590
 591 /* send an exception event */
 592 DECL_HANDLER(exception_event)
 593 {
 594     req->status = 0;
 595     if (current->process->debugger)
 596     {
 597         struct debug_event_exception data;
 598         struct debug_event *event;
 599         CONTEXT *context = get_req_data( req );
 600         EXCEPTION_RECORD *rec = (EXCEPTION_RECORD *)(context + 1);
 601
 602         if (get_req_data_size( req ) < sizeof(*rec) + sizeof(*context))
 603         {
 604             set_error( STATUS_INVALID_PARAMETER );
 605             return;
 606         }
 607         data.record = *rec;
 608         data.first  = req->first;
 609         if ((event = queue_debug_event( current, EXCEPTION_DEBUG_EVENT, &data )))
 610         {
 611             struct object *obj = &event->obj;
 612             current->context = context;
 613             sleep_on( 1, &obj, 0, 0, 0, build_exception_event_reply );
 614             release_object( event );
 615         }
 616     }
 617 }
 618
 619 /* send an output string to the debugger */
 620 DECL_HANDLER(output_debug_string)
 621 {
 622     if (current->process->debugger)
 623     {
 624         struct debug_event *event = queue_debug_event( current, OUTPUT_DEBUG_STRING_EVENT, req );
 625         if (event) release_object( event );
 626     }
 627 }