?  search:
summary | log | graphiclog1 | graphiclog2 | commit | commitdiff | tree | refs | edit | fork
blame | history | raw | HEAD
vfs: check userland buffers before reading them.
[haiku.git] / src / system / kernel / syscalls.cpp
blob40d538780f5435a87f26ff3a689f00d086037354
1 /*
2 * Copyright 2008, Ingo Weinhold, ingo_weinhold@gmx.de.
3 * Copyright 2004-2010, Haiku Inc. All rights reserved.
4 * Distributed under the terms of the MIT License.
5 */
6
7
8 /*! Big case statement for dispatching syscalls, as well as the generic
9 syscall interface.
10 */
11
12
13 #include <syscalls.h>
14
15 #include <stdlib.h>
16 #include <string.h>
17
18 #include <TypeConstants.h>
19
20 #include <arch_config.h>
21 #include <arch/system_info.h>
22 #include <cpu.h>
23 #include <debug.h>
24 #include <disk_device_manager/ddm_userland_interface.h>
25 #include <elf.h>
26 #include <frame_buffer_console.h>
27 #include <fs/fd.h>
28 #include <fs/node_monitor.h>
29 #include <generic_syscall.h>
30 #include <int.h>
31 #include <kernel.h>
32 #include <kimage.h>
33 #include <ksignal.h>
34 #include <ksyscalls.h>
35 #include <ksystem_info.h>
36 #include <messaging.h>
37 #include <port.h>
38 #include <posix/realtime_sem.h>
39 #include <posix/xsi_message_queue.h>
40 #include <posix/xsi_semaphore.h>
41 #include <real_time_clock.h>
42 #include <safemode.h>
43 #include <sem.h>
44 #include <sys/resource.h>
45 #include <system_profiler.h>
46 #include <thread.h>
47 #include <tracing.h>
48 #include <user_atomic.h>
49 #include <user_mutex.h>
50 #include <usergroup.h>
51 #include <UserTimer.h>
52 #include <util/AutoLock.h>
53 #include <vfs.h>
54 #include <vm/vm.h>
55 #include <wait_for_objects.h>
56
57 #include "syscall_numbers.h"
58
59
60 typedef struct generic_syscall generic_syscall;
61
62 struct generic_syscall : DoublyLinkedListLinkImpl<generic_syscall> {
63 char subsystem[B_FILE_NAME_LENGTH];
64 syscall_hook hook;
65 uint32 version;
66 uint32 flags;
67 int32 use_count;
68 bool valid;
69 ConditionVariable unused_condition;
70 generic_syscall* previous;
71 };
72
73 typedef DoublyLinkedList<generic_syscall> GenericSyscallList;
74
75
76 static mutex sGenericSyscallLock = MUTEX_INITIALIZER("generic syscall");
77 static GenericSyscallList sGenericSyscalls;
78
79
80 #if SYSCALL_TRACING
81 static int dump_syscall_tracing(int argc, char** argv);
82 #endif
83
84
85 static generic_syscall*
86 find_generic_syscall(const char* subsystem)
87 {
88 ASSERT_LOCKED_MUTEX(&sGenericSyscallLock);
89
90 GenericSyscallList::Iterator iterator = sGenericSyscalls.GetIterator();
91
92 while (generic_syscall* syscall = iterator.Next()) {
93 if (!strcmp(syscall->subsystem, subsystem))
94 return syscall;
95 }
96
97 return NULL;
98 }
99
100
101 /*! Calls the generic syscall subsystem if any.
102 Also handles the special generic syscall function \c B_SYSCALL_INFO.
103 Returns \c B_NAME_NOT_FOUND if either the subsystem was not found, or
104 the subsystem does not support the requested function.
105 All other return codes are depending on the generic syscall implementation.
106 */
107 static inline status_t
108 _user_generic_syscall(const char* userSubsystem, uint32 function,
109 void* buffer, size_t bufferSize)
110 {
111 char subsystem[B_FILE_NAME_LENGTH];
112
113 if (!IS_USER_ADDRESS(userSubsystem)
114 || user_strlcpy(subsystem, userSubsystem, sizeof(subsystem)) < B_OK)
115 return B_BAD_ADDRESS;
116
117 //dprintf("generic_syscall(subsystem = \"%s\", function = %lu)\n", subsystem, function);
118
119 MutexLocker locker(sGenericSyscallLock);
120
121 generic_syscall* syscall = find_generic_syscall(subsystem);
122 if (syscall == NULL)
123 return B_NAME_NOT_FOUND;
124
125 if (function >= B_RESERVED_SYSCALL_BASE) {
126 if (function != B_SYSCALL_INFO) {
127 // this is all we know
128 return B_NAME_NOT_FOUND;
129 }
130
131 // special info syscall
132 if (bufferSize != sizeof(uint32))
133 return B_BAD_VALUE;
134
135 uint32 requestedVersion;
136
137 // retrieve old version
138 if (user_memcpy(&requestedVersion, buffer, sizeof(uint32)) != B_OK)
139 return B_BAD_ADDRESS;
140 if (requestedVersion != 0 && requestedVersion < syscall->version)
141 return B_BAD_TYPE;
142
143 // return current version
144 return user_memcpy(buffer, &syscall->version, sizeof(uint32));
145 }
146
147 while (syscall != NULL) {
148 generic_syscall* next;
149
150 if (syscall->valid) {
151 syscall->use_count++;
152 locker.Unlock();
153
154 status_t status
155 = syscall->hook(subsystem, function, buffer, bufferSize);
156
157 locker.Lock();
158
159 if (--syscall->use_count == 0)
160 syscall->unused_condition.NotifyAll();
161
162 if (status != B_BAD_HANDLER)
163 return status;
164 }
165
166 // the syscall may have been removed in the mean time
167 next = find_generic_syscall(subsystem);
168 if (next == syscall)
169 syscall = syscall->previous;
170 else
171 syscall = next;
172 }
173
174 return B_NAME_NOT_FOUND;
175 }
176
177
178 static inline int
179 _user_is_computer_on(void)
180 {
181 return 1;
182 }
183
184
185 // #pragma mark -
186
187
188 int32
189 syscall_dispatcher(uint32 callIndex, void* args, uint64* _returnValue)
190 {
191 bigtime_t startTime;
192
193 // dprintf("syscall_dispatcher: thread 0x%x call 0x%x, arg0 0x%x, arg1 0x%x arg2 0x%x arg3 0x%x arg4 0x%x\n",
194 // thread_get_current_thread_id(), call_num, arg0, arg1, arg2, arg3, arg4);
195
196 user_debug_pre_syscall(callIndex, args);
197
198 startTime = system_time();
199
200 switch (callIndex) {
201 // the cases are auto-generated
202 #include "syscall_dispatcher.h"
203
204 default:
205 *_returnValue = (uint64)B_BAD_VALUE;
206 }
207
208 user_debug_post_syscall(callIndex, args, *_returnValue, startTime);
209
210 // dprintf("syscall_dispatcher: done with syscall 0x%x\n", callIndex);
211
212 return B_HANDLED_INTERRUPT;
213 }
214
215
216 status_t
217 generic_syscall_init(void)
218 {
219 new(&sGenericSyscalls) GenericSyscallList;
220
221 #if SYSCALL_TRACING
222 add_debugger_command_etc("straced", &dump_syscall_tracing,
223 "Dump recorded syscall trace entries",
224 "Prints recorded trace entries. It is wrapper for the \"traced\"\n"
225 "command and supports all of its command line options (though\n"
226 "backward tracing doesn't really work). The difference is that if a\n"
227 "pre syscall trace entry is encountered, the corresponding post\n"
228 "syscall traced entry is also printed, even if it doesn't match the\n"
229 "given filter.\n", 0);
230 #endif // ENABLE_TRACING
231
232 return B_OK;
233 }
234
235
236 // #pragma mark - public API
237
238
239 status_t
240 register_generic_syscall(const char* subsystem, syscall_hook hook,
241 uint32 version, uint32 flags)
242 {
243 if (hook == NULL)
244 return B_BAD_VALUE;
245
246 MutexLocker _(sGenericSyscallLock);
247
248 generic_syscall* previous = find_generic_syscall(subsystem);
249 if (previous != NULL) {
250 if ((flags & B_DO_NOT_REPLACE_SYSCALL) != 0
251 || version < previous->version) {
252 return B_NAME_IN_USE;
253 }
254 if ((previous->flags & B_SYSCALL_NOT_REPLACEABLE) != 0)
255 return B_NOT_ALLOWED;
256 }
257
258 generic_syscall* syscall = new(std::nothrow) generic_syscall;
259 if (syscall == NULL)
260 return B_NO_MEMORY;
261
262 strlcpy(syscall->subsystem, subsystem, sizeof(syscall->subsystem));
263 syscall->hook = hook;
264 syscall->version = version;
265 syscall->flags = flags;
266 syscall->use_count = 0;
267 syscall->valid = true;
268 syscall->previous = previous;
269 syscall->unused_condition.Init(syscall, "syscall unused");
270
271 sGenericSyscalls.Add(syscall);
272
273 if (previous != NULL)
274 sGenericSyscalls.Remove(previous);
275
276 return B_OK;
277 }
278
279
280 status_t
281 unregister_generic_syscall(const char* subsystem, uint32 version)
282 {
283 // TODO: we should only remove the syscall with the matching version
284
285 while (true) {
286 MutexLocker locker(sGenericSyscallLock);
287
288 generic_syscall* syscall = find_generic_syscall(subsystem);
289 if (syscall == NULL)
290 return B_NAME_NOT_FOUND;
291
292 syscall->valid = false;
293
294 if (syscall->use_count != 0) {
295 // Wait until the syscall isn't in use anymore
296 ConditionVariableEntry entry;
297 syscall->unused_condition.Add(&entry);
298
299 locker.Unlock();
300
301 entry.Wait();
302 continue;
303 }
304
305 if (syscall->previous != NULL) {
306 // reestablish the old syscall
307 sGenericSyscalls.Add(syscall->previous);
308 }
309
310 sGenericSyscalls.Remove(syscall);
311 delete syscall;
312
313 return B_OK;
314 }
315 }
316
317
318 // #pragma mark - syscall tracing
319
320
321 #if SYSCALL_TRACING
322
323 namespace SyscallTracing {
324
325
326 static const char*
327 get_syscall_name(uint32 syscall)
328 {
329 if (syscall >= (uint32)kSyscallCount)
330 return "<invalid syscall number>";
331
332 return kExtendedSyscallInfos[syscall].name;
333 }
334
335
336 class PreSyscall : public AbstractTraceEntry {
337 public:
338 PreSyscall(uint32 syscall, const void* parameters)
339 :
340 fSyscall(syscall),
341 fParameters(NULL)
342 {
343 if (syscall < (uint32)kSyscallCount) {
344 fParameters = alloc_tracing_buffer_memcpy(parameters,
345 kSyscallInfos[syscall].parameter_size, false);
346
347 // copy string parameters, if any
348 if (fParameters != NULL && syscall != SYSCALL_KTRACE_OUTPUT) {
349 int32 stringIndex = 0;
350 const extended_syscall_info& syscallInfo
351 = kExtendedSyscallInfos[fSyscall];
352 for (int i = 0; i < syscallInfo.parameter_count; i++) {
353 const syscall_parameter_info& paramInfo
354 = syscallInfo.parameters[i];
355 if (paramInfo.type != B_STRING_TYPE)
356 continue;
357
358 const uint8* data
359 = (uint8*)fParameters + paramInfo.offset;
360 if (stringIndex < MAX_PARAM_STRINGS) {
361 fParameterStrings[stringIndex++]
362 = alloc_tracing_buffer_strcpy(
363 *(const char**)data, 64, true);
364 }
365 }
366 }
367 }
368
369 Initialized();
370 }
371
372 virtual void AddDump(TraceOutput& out)
373 {
374 out.Print("syscall pre: %s(", get_syscall_name(fSyscall));
375
376 if (fParameters != NULL) {
377 int32 stringIndex = 0;
378 const extended_syscall_info& syscallInfo
379 = kExtendedSyscallInfos[fSyscall];
380 for (int i = 0; i < syscallInfo.parameter_count; i++) {
381 const syscall_parameter_info& paramInfo
382 = syscallInfo.parameters[i];
383 const uint8* data = (uint8*)fParameters + paramInfo.offset;
384 uint64 value = 0;
385 bool printValue = true;
386 switch (paramInfo.type) {
387 case B_INT8_TYPE:
388 value = *(uint8*)data;
389 break;
390 case B_INT16_TYPE:
391 value = *(uint16*)data;
392 break;
393 case B_INT32_TYPE:
394 value = *(uint32*)data;
395 break;
396 case B_INT64_TYPE:
397 value = *(uint64*)data;
398 break;
399 case B_POINTER_TYPE:
400 value = (uint64)*(void**)data;
401 break;
402 case B_STRING_TYPE:
403 if (stringIndex < MAX_PARAM_STRINGS
404 && fSyscall != SYSCALL_KTRACE_OUTPUT) {
405 out.Print("%s\"%s\"",
406 (i == 0 ? "" : ", "),
407 fParameterStrings[stringIndex++]);
408 printValue = false;
409 } else
410 value = (uint64)*(void**)data;
411 break;
412 }
413
414 if (printValue)
415 out.Print("%s%#" B_PRIx64, (i == 0 ? "" : ", "), value);
416 }
417 }
418
419 out.Print(")");
420 }
421
422 private:
423 enum { MAX_PARAM_STRINGS = 3 };
424
425 uint32 fSyscall;
426 void* fParameters;
427 const char* fParameterStrings[MAX_PARAM_STRINGS];
428 };
429
430
431 class PostSyscall : public AbstractTraceEntry {
432 public:
433 PostSyscall(uint32 syscall, uint64 returnValue)
434 :
435 fSyscall(syscall),
436 fReturnValue(returnValue)
437 {
438 Initialized();
439 #if 0
440 if (syscall < (uint32)kSyscallCount
441 && returnValue != (returnValue & 0xffffffff)
442 && kExtendedSyscallInfos[syscall].return_type.size <= 4) {
443 panic("syscall return value 64 bit although it should be 32 "
444 "bit");
445 }
446 #endif
447 }
448
449 virtual void AddDump(TraceOutput& out)
450 {
451 out.Print("syscall post: %s() -> %#" B_PRIx64,
452 get_syscall_name(fSyscall), fReturnValue);
453 }
454
455 private:
456 uint32 fSyscall;
457 uint64 fReturnValue;
458 };
459
460 } // namespace SyscallTracing
461
462
463 extern "C" void trace_pre_syscall(uint32 syscallNumber, const void* parameters);
464
465 void
466 trace_pre_syscall(uint32 syscallNumber, const void* parameters)
467 {
468 #if SYSCALL_TRACING_IGNORE_KTRACE_OUTPUT
469 if (syscallNumber != SYSCALL_KTRACE_OUTPUT)
470 #endif
471 {
472 new(std::nothrow) SyscallTracing::PreSyscall(syscallNumber, parameters);
473 }
474 }
475
476
477 extern "C" void trace_post_syscall(int syscallNumber, uint64 returnValue);
478
479 void
480 trace_post_syscall(int syscallNumber, uint64 returnValue)
481 {
482 #if SYSCALL_TRACING_IGNORE_KTRACE_OUTPUT
483 if (syscallNumber != SYSCALL_KTRACE_OUTPUT)
484 #endif
485 {
486 new(std::nothrow) SyscallTracing::PostSyscall(syscallNumber,
487 returnValue);
488 }
489 }
490
491
492 using namespace SyscallTracing;
493
494 class SyscallWrapperTraceFilter : public WrapperTraceFilter {
495 public:
496 virtual void Init(TraceFilter* filter, int direction, bool continued)
497 {
498 fFilter = filter;
499 fHitThreadLimit = false;
500 fDirection = direction;
501
502 if (!continued)
503 fPendingThreadCount = 0;
504 }
505
506 virtual bool Filter(const TraceEntry* _entry, LazyTraceOutput& out)
507 {
508 if (fFilter == NULL)
509 return true;
510
511 if (fDirection < 0)
512 return fFilter->Filter(_entry, out);
513
514 if (const PreSyscall* entry = dynamic_cast<const PreSyscall*>(_entry)) {
515 _RemovePendingThread(entry->ThreadID());
516
517 bool accepted = fFilter->Filter(entry, out);
518 if (accepted)
519 _AddPendingThread(entry->ThreadID());
520 return accepted;
521
522 } else if (const PostSyscall* entry
523 = dynamic_cast<const PostSyscall*>(_entry)) {
524 bool wasPending = _RemovePendingThread(entry->ThreadID());
525
526 return wasPending || fFilter->Filter(entry, out);
527
528 } else if (const AbstractTraceEntry* entry
529 = dynamic_cast<const AbstractTraceEntry*>(_entry)) {
530 bool isPending = _IsPendingThread(entry->ThreadID());
531
532 return isPending || fFilter->Filter(entry, out);
533
534 } else {
535 return fFilter->Filter(_entry, out);
536 }
537 }
538
539 bool HitThreadLimit() const
540 {
541 return fHitThreadLimit;
542 }
543
544 int Direction() const
545 {
546 return fDirection;
547 }
548
549 private:
550 enum {
551 MAX_PENDING_THREADS = 32
552 };
553
554 bool _AddPendingThread(thread_id thread)
555 {
556 int32 index = _PendingThreadIndex(thread);
557 if (index >= 0)
558 return true;
559
560 if (fPendingThreadCount == MAX_PENDING_THREADS) {
561 fHitThreadLimit = true;
562 return false;
563 }
564
565 fPendingThreads[fPendingThreadCount++] = thread;
566 return true;
567 }
568
569 bool _RemovePendingThread(thread_id thread)
570 {
571 int32 index = _PendingThreadIndex(thread);
572 if (index < 0)
573 return false;
574
575 if (index + 1 < fPendingThreadCount) {
576 memmove(fPendingThreads + index, fPendingThreads + index + 1,
577 fPendingThreadCount - index - 1);
578 }
579
580 fPendingThreadCount--;
581 return true;
582 }
583
584 bool _IsPendingThread(thread_id thread)
585 {
586 return _PendingThreadIndex(thread) >= 0;
587 }
588
589 int32 _PendingThreadIndex(thread_id thread)
590 {
591 for (int32 i = 0; i < fPendingThreadCount; i++) {
592 if (fPendingThreads[i] == thread)
593 return i;
594 }
595 return -1;
596 }
597
598 TraceFilter* fFilter;
599 thread_id fPendingThreads[MAX_PENDING_THREADS];
600 int32 fPendingThreadCount;
601 int fDirection;
602 bool fHitThreadLimit;
603 };
604
605
606 static SyscallWrapperTraceFilter sFilter;
607
608 static int
609 dump_syscall_tracing(int argc, char** argv)
610 {
611 new(&sFilter) SyscallWrapperTraceFilter;
612 int result = dump_tracing(argc, argv, &sFilter);
613
614 if (sFilter.HitThreadLimit()) {
615 kprintf("Warning: The thread buffer was too small to track all "
616 "threads!\n");
617 } else if (sFilter.HitThreadLimit()) {
618 kprintf("Warning: Can't track syscalls backwards!\n");
619 }
620
621 return result;
622 }
623
624
625 #endif // SYSCALL_TRACING
626
627
628 /*
629 * kSyscallCount and kSyscallInfos here
630 */
631 // generated by gensyscalls
632 #include "syscall_table.h"
Clone of Haiku svn repository