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1 /*
2  * Copyright (C) 2012 The Android Open Source Project
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  *  * Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  *  * Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in
12  *    the documentation and/or other materials provided with the
13  *    distribution.
14  *
15  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
17  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
18  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
19  * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
21  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
22  * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
23  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
24  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
25  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  */
28 
29 #include <errno.h>
30 #include <inttypes.h>
31 #include <malloc.h>
32 #include <pthread.h>
33 #include <signal.h>
34 #include <stdio.h>
35 #include <stdlib.h>
36 #include <string.h>
37 #include <sys/cdefs.h>
38 #include <sys/param.h>
39 #include <sys/syscall.h>
40 #include <unistd.h>
41 
42 #include <mutex>
43 #include <vector>
44 
45 #include <android-base/file.h>
46 #include <android-base/properties.h>
47 #include <android-base/stringprintf.h>
48 #include <bionic/malloc_tagged_pointers.h>
49 #include <platform/bionic/reserved_signals.h>
50 #include <private/MallocXmlElem.h>
51 #include <private/bionic_malloc_dispatch.h>
52 
53 #include "Config.h"
54 #include "DebugData.h"
55 #include "backtrace.h"
56 #include "debug_disable.h"
57 #include "debug_log.h"
58 #include "malloc_debug.h"
59 #include "UnwindBacktrace.h"
60 
61 // ------------------------------------------------------------------------
62 // Global Data
63 // ------------------------------------------------------------------------
64 DebugData* g_debug;
65 
66 bool* g_zygote_child;
67 
68 const MallocDispatch* g_dispatch;
69 // ------------------------------------------------------------------------
70 
71 // ------------------------------------------------------------------------
72 // Use C style prototypes for all exported functions. This makes it easy
73 // to do dlsym lookups during libc initialization when malloc debug
74 // is enabled.
75 // ------------------------------------------------------------------------
76 __BEGIN_DECLS
77 
78 bool debug_initialize(const MallocDispatch* malloc_dispatch, bool* malloc_zygote_child,
79                       const char* options);
80 void debug_finalize();
81 void debug_dump_heap(const char* file_name);
82 void debug_get_malloc_leak_info(uint8_t** info, size_t* overall_size, size_t* info_size,
83                                 size_t* total_memory, size_t* backtrace_size);
84 bool debug_write_malloc_leak_info(FILE* fp);
85 ssize_t debug_malloc_backtrace(void* pointer, uintptr_t* frames, size_t frame_count);
86 void debug_free_malloc_leak_info(uint8_t* info);
87 size_t debug_malloc_usable_size(void* pointer);
88 void* debug_malloc(size_t size);
89 void debug_free(void* pointer);
90 void* debug_aligned_alloc(size_t alignment, size_t size);
91 void* debug_memalign(size_t alignment, size_t bytes);
92 void* debug_realloc(void* pointer, size_t bytes);
93 void* debug_calloc(size_t nmemb, size_t bytes);
94 struct mallinfo debug_mallinfo();
95 int debug_mallopt(int param, int value);
96 int debug_malloc_info(int options, FILE* fp);
97 int debug_posix_memalign(void** memptr, size_t alignment, size_t size);
98 int debug_malloc_iterate(uintptr_t base, size_t size,
99                          void (*callback)(uintptr_t base, size_t size, void* arg), void* arg);
100 void debug_malloc_disable();
101 void debug_malloc_enable();
102 
103 #if defined(HAVE_DEPRECATED_MALLOC_FUNCS)
104 void* debug_pvalloc(size_t bytes);
105 void* debug_valloc(size_t size);
106 #endif
107 
108 __END_DECLS
109 // ------------------------------------------------------------------------
110 
111 class ScopedConcurrentLock {
112  public:
ScopedConcurrentLock()113   ScopedConcurrentLock() {
114     pthread_rwlock_rdlock(&lock_);
115   }
~ScopedConcurrentLock()116   ~ScopedConcurrentLock() {
117     pthread_rwlock_unlock(&lock_);
118   }
119 
Init()120   static void Init() {
121     pthread_rwlockattr_t attr;
122     // Set the attribute so that when a write lock is pending, read locks are no
123     // longer granted.
124     pthread_rwlockattr_setkind_np(&attr, PTHREAD_RWLOCK_PREFER_WRITER_NONRECURSIVE_NP);
125     pthread_rwlock_init(&lock_, &attr);
126   }
127 
BlockAllOperations()128   static void BlockAllOperations() {
129     pthread_rwlock_wrlock(&lock_);
130   }
131 
132  private:
133   static pthread_rwlock_t lock_;
134 };
135 pthread_rwlock_t ScopedConcurrentLock::lock_;
136 
137 // Use this because the sigprocmask* functions filter out the reserved bionic
138 // signals including the signal this code blocks.
__rt_sigprocmask(int how,const sigset64_t * new_set,sigset64_t * old_set,size_t sigset_size)139 static inline int __rt_sigprocmask(int how, const sigset64_t* new_set, sigset64_t* old_set,
140                                    size_t sigset_size) {
141   return syscall(SYS_rt_sigprocmask, how, new_set, old_set, sigset_size);
142 }
143 
144 // Need to block the backtrace signal while in malloc debug routines
145 // otherwise there is a chance of a deadlock and timeout when unwinding.
146 // This can occur if a thread is paused while owning a malloc debug
147 // internal lock.
148 class ScopedBacktraceSignalBlocker {
149  public:
ScopedBacktraceSignalBlocker()150   ScopedBacktraceSignalBlocker() {
151     sigemptyset64(&backtrace_set_);
152     sigaddset64(&backtrace_set_, BIONIC_SIGNAL_BACKTRACE);
153     sigset64_t old_set;
154     __rt_sigprocmask(SIG_BLOCK, &backtrace_set_, &old_set, sizeof(backtrace_set_));
155     if (sigismember64(&old_set, BIONIC_SIGNAL_BACKTRACE)) {
156       unblock_ = false;
157     }
158   }
159 
~ScopedBacktraceSignalBlocker()160   ~ScopedBacktraceSignalBlocker() {
161     if (unblock_) {
162       __rt_sigprocmask(SIG_UNBLOCK, &backtrace_set_, nullptr, sizeof(backtrace_set_));
163     }
164   }
165 
166  private:
167   bool unblock_ = true;
168   sigset64_t backtrace_set_;
169 };
170 
InitAtfork()171 static void InitAtfork() {
172   static pthread_once_t atfork_init = PTHREAD_ONCE_INIT;
173   pthread_once(&atfork_init, []() {
174     pthread_atfork(
175         []() {
176           if (g_debug != nullptr) {
177             g_debug->PrepareFork();
178           }
179         },
180         []() {
181           if (g_debug != nullptr) {
182             g_debug->PostForkParent();
183           }
184         },
185         []() {
186           if (g_debug != nullptr) {
187             g_debug->PostForkChild();
188           }
189         });
190   });
191 }
192 
BacktraceAndLog()193 void BacktraceAndLog() {
194   if (g_debug->config().options() & BACKTRACE_FULL) {
195     std::vector<uintptr_t> frames;
196     std::vector<unwindstack::LocalFrameData> frames_info;
197     if (!Unwind(&frames, &frames_info, 256)) {
198       error_log("  Backtrace failed to get any frames.");
199     } else {
200       UnwindLog(frames_info);
201     }
202   } else {
203     std::vector<uintptr_t> frames(256);
204     size_t num_frames = backtrace_get(frames.data(), frames.size());
205     if (num_frames == 0) {
206       error_log("  Backtrace failed to get any frames.");
207     } else {
208       backtrace_log(frames.data(), num_frames);
209     }
210   }
211 }
212 
LogError(const void * pointer,const char * error_str)213 static void LogError(const void* pointer, const char* error_str) {
214   error_log(LOG_DIVIDER);
215   error_log("+++ ALLOCATION %p %s", pointer, error_str);
216 
217   // If we are tracking already freed pointers, check to see if this is
218   // one so we can print extra information.
219   if (g_debug->config().options() & FREE_TRACK) {
220     PointerData::LogFreeBacktrace(pointer);
221   }
222 
223   error_log("Backtrace at time of failure:");
224   BacktraceAndLog();
225   error_log(LOG_DIVIDER);
226   if (g_debug->config().options() & ABORT_ON_ERROR) {
227     abort();
228   }
229 }
230 
VerifyPointer(const void * pointer,const char * function_name)231 static bool VerifyPointer(const void* pointer, const char* function_name) {
232   if (g_debug->HeaderEnabled()) {
233     Header* header = g_debug->GetHeader(pointer);
234     if (header->tag != DEBUG_TAG) {
235       std::string error_str;
236       if (header->tag == DEBUG_FREE_TAG) {
237         error_str = std::string("USED AFTER FREE (") + function_name + ")";
238       } else {
239         error_str = android::base::StringPrintf("HAS INVALID TAG %" PRIx32 " (%s)", header->tag,
240                                                 function_name);
241       }
242       LogError(pointer, error_str.c_str());
243       return false;
244     }
245   }
246 
247   if (g_debug->TrackPointers()) {
248     if (!PointerData::Exists(pointer)) {
249       std::string error_str(std::string("UNKNOWN POINTER (") + function_name + ")");
250       LogError(pointer, error_str.c_str());
251       return false;
252     }
253   }
254   return true;
255 }
256 
InternalMallocUsableSize(void * pointer)257 static size_t InternalMallocUsableSize(void* pointer) {
258   if (g_debug->HeaderEnabled()) {
259     return g_debug->GetHeader(pointer)->usable_size;
260   } else {
261     return g_dispatch->malloc_usable_size(pointer);
262   }
263 }
264 
InitHeader(Header * header,void * orig_pointer,size_t size)265 static void* InitHeader(Header* header, void* orig_pointer, size_t size) {
266   header->tag = DEBUG_TAG;
267   header->orig_pointer = orig_pointer;
268   header->size = size;
269   header->usable_size = g_dispatch->malloc_usable_size(orig_pointer);
270   if (header->usable_size == 0) {
271     g_dispatch->free(orig_pointer);
272     return nullptr;
273   }
274   header->usable_size -= g_debug->pointer_offset() + reinterpret_cast<uintptr_t>(header) -
275                          reinterpret_cast<uintptr_t>(orig_pointer);
276 
277   if (g_debug->config().options() & FRONT_GUARD) {
278     uint8_t* guard = g_debug->GetFrontGuard(header);
279     memset(guard, g_debug->config().front_guard_value(), g_debug->config().front_guard_bytes());
280   }
281 
282   if (g_debug->config().options() & REAR_GUARD) {
283     uint8_t* guard = g_debug->GetRearGuard(header);
284     memset(guard, g_debug->config().rear_guard_value(), g_debug->config().rear_guard_bytes());
285     // If the rear guard is enabled, set the usable size to the exact size
286     // of the allocation.
287     header->usable_size = header->size;
288   }
289 
290   return g_debug->GetPointer(header);
291 }
292 
293 extern "C" void __asan_init() __attribute__((weak));
294 
debug_initialize(const MallocDispatch * malloc_dispatch,bool * zygote_child,const char * options)295 bool debug_initialize(const MallocDispatch* malloc_dispatch, bool* zygote_child,
296                       const char* options) {
297   if (zygote_child == nullptr || options == nullptr) {
298     return false;
299   }
300 
301   if (__asan_init != 0) {
302     error_log("malloc debug cannot be enabled alongside ASAN");
303     return false;
304   }
305 
306   InitAtfork();
307 
308   g_zygote_child = zygote_child;
309 
310   g_dispatch = malloc_dispatch;
311 
312   if (!DebugDisableInitialize()) {
313     return false;
314   }
315 
316   DebugData* debug = new DebugData();
317   if (!debug->Initialize(options)) {
318     delete debug;
319     DebugDisableFinalize();
320     return false;
321   }
322   g_debug = debug;
323 
324   // Always enable the backtrace code since we will use it in a number
325   // of different error cases.
326   backtrace_startup();
327 
328   if (g_debug->config().options() & VERBOSE) {
329     info_log("%s: malloc debug enabled", getprogname());
330   }
331 
332   ScopedConcurrentLock::Init();
333 
334   return true;
335 }
336 
debug_finalize()337 void debug_finalize() {
338   if (g_debug == nullptr) {
339     return;
340   }
341 
342   // Make sure that there are no other threads doing debug allocations
343   // before we kill everything.
344   ScopedConcurrentLock::BlockAllOperations();
345 
346   // Turn off capturing allocations calls.
347   DebugDisableSet(true);
348 
349   if (g_debug->config().options() & FREE_TRACK) {
350     PointerData::VerifyAllFreed();
351   }
352 
353   if (g_debug->config().options() & LEAK_TRACK) {
354     PointerData::LogLeaks();
355   }
356 
357   if ((g_debug->config().options() & BACKTRACE) && g_debug->config().backtrace_dump_on_exit()) {
358     debug_dump_heap(android::base::StringPrintf("%s.%d.exit.txt",
359                                                 g_debug->config().backtrace_dump_prefix().c_str(),
360                                                 getpid()).c_str());
361   }
362 
363   backtrace_shutdown();
364 
365   delete g_debug;
366   g_debug = nullptr;
367 
368   DebugDisableFinalize();
369 }
370 
debug_get_malloc_leak_info(uint8_t ** info,size_t * overall_size,size_t * info_size,size_t * total_memory,size_t * backtrace_size)371 void debug_get_malloc_leak_info(uint8_t** info, size_t* overall_size, size_t* info_size,
372                                 size_t* total_memory, size_t* backtrace_size) {
373   ScopedConcurrentLock lock;
374   ScopedDisableDebugCalls disable;
375   ScopedBacktraceSignalBlocker blocked;
376 
377   // Verify the arguments.
378   if (info == nullptr || overall_size == nullptr || info_size == nullptr || total_memory == nullptr ||
379       backtrace_size == nullptr) {
380     error_log("get_malloc_leak_info: At least one invalid parameter.");
381     return;
382   }
383 
384   *info = nullptr;
385   *overall_size = 0;
386   *info_size = 0;
387   *total_memory = 0;
388   *backtrace_size = 0;
389 
390   if (!(g_debug->config().options() & BACKTRACE)) {
391     error_log(
392         "get_malloc_leak_info: Allocations not being tracked, to enable "
393         "set the option 'backtrace'.");
394     return;
395   }
396 
397   PointerData::GetInfo(info, overall_size, info_size, total_memory, backtrace_size);
398 }
399 
debug_free_malloc_leak_info(uint8_t * info)400 void debug_free_malloc_leak_info(uint8_t* info) {
401   g_dispatch->free(info);
402 }
403 
debug_malloc_usable_size(void * pointer)404 size_t debug_malloc_usable_size(void* pointer) {
405   if (DebugCallsDisabled() || pointer == nullptr) {
406     return g_dispatch->malloc_usable_size(pointer);
407   }
408   ScopedConcurrentLock lock;
409   ScopedDisableDebugCalls disable;
410   ScopedBacktraceSignalBlocker blocked;
411 
412   if (!VerifyPointer(pointer, "malloc_usable_size")) {
413     return 0;
414   }
415 
416   return InternalMallocUsableSize(pointer);
417 }
418 
InternalMalloc(size_t size)419 static void* InternalMalloc(size_t size) {
420   if ((g_debug->config().options() & BACKTRACE) && g_debug->pointer->ShouldDumpAndReset()) {
421     debug_dump_heap(android::base::StringPrintf(
422                         "%s.%d.txt", g_debug->config().backtrace_dump_prefix().c_str(), getpid())
423                         .c_str());
424   }
425 
426   if (size == 0) {
427     size = 1;
428   }
429 
430   size_t real_size = size + g_debug->extra_bytes();
431   if (real_size < size) {
432     // Overflow.
433     errno = ENOMEM;
434     return nullptr;
435   }
436 
437   if (size > PointerInfoType::MaxSize()) {
438     errno = ENOMEM;
439     return nullptr;
440   }
441 
442   void* pointer;
443   if (g_debug->HeaderEnabled()) {
444     Header* header =
445         reinterpret_cast<Header*>(g_dispatch->memalign(MINIMUM_ALIGNMENT_BYTES, real_size));
446     if (header == nullptr) {
447       return nullptr;
448     }
449     pointer = InitHeader(header, header, size);
450   } else {
451     pointer = g_dispatch->malloc(real_size);
452   }
453 
454   if (pointer != nullptr) {
455     if (g_debug->TrackPointers()) {
456       PointerData::Add(pointer, size);
457     }
458 
459     if (g_debug->config().options() & FILL_ON_ALLOC) {
460       size_t bytes = InternalMallocUsableSize(pointer);
461       size_t fill_bytes = g_debug->config().fill_on_alloc_bytes();
462       bytes = (bytes < fill_bytes) ? bytes : fill_bytes;
463       memset(pointer, g_debug->config().fill_alloc_value(), bytes);
464     }
465   }
466   return pointer;
467 }
468 
debug_malloc(size_t size)469 void* debug_malloc(size_t size) {
470   if (DebugCallsDisabled()) {
471     return g_dispatch->malloc(size);
472   }
473   ScopedConcurrentLock lock;
474   ScopedDisableDebugCalls disable;
475   ScopedBacktraceSignalBlocker blocked;
476 
477   void* pointer = InternalMalloc(size);
478 
479   if (g_debug->config().options() & RECORD_ALLOCS) {
480     g_debug->record->AddEntry(new MallocEntry(pointer, size));
481   }
482 
483   return pointer;
484 }
485 
InternalFree(void * pointer)486 static void InternalFree(void* pointer) {
487   if ((g_debug->config().options() & BACKTRACE) && g_debug->pointer->ShouldDumpAndReset()) {
488     debug_dump_heap(android::base::StringPrintf(
489                         "%s.%d.txt", g_debug->config().backtrace_dump_prefix().c_str(), getpid())
490                         .c_str());
491   }
492 
493   void* free_pointer = pointer;
494   size_t bytes;
495   Header* header;
496   if (g_debug->HeaderEnabled()) {
497     header = g_debug->GetHeader(pointer);
498     free_pointer = header->orig_pointer;
499 
500     if (g_debug->config().options() & FRONT_GUARD) {
501       if (!g_debug->front_guard->Valid(header)) {
502         g_debug->front_guard->LogFailure(header);
503       }
504     }
505     if (g_debug->config().options() & REAR_GUARD) {
506       if (!g_debug->rear_guard->Valid(header)) {
507         g_debug->rear_guard->LogFailure(header);
508       }
509     }
510 
511     header->tag = DEBUG_FREE_TAG;
512 
513     bytes = header->usable_size;
514   } else {
515     bytes = g_dispatch->malloc_usable_size(pointer);
516   }
517 
518   if (g_debug->config().options() & FILL_ON_FREE) {
519     size_t fill_bytes = g_debug->config().fill_on_free_bytes();
520     bytes = (bytes < fill_bytes) ? bytes : fill_bytes;
521     memset(pointer, g_debug->config().fill_free_value(), bytes);
522   }
523 
524   if (g_debug->TrackPointers()) {
525     PointerData::Remove(pointer);
526   }
527 
528   if (g_debug->config().options() & FREE_TRACK) {
529     // Do not add the allocation until we are done modifying the pointer
530     // itself. This avoids a race if a lot of threads are all doing
531     // frees at the same time and we wind up trying to really free this
532     // pointer from another thread, while still trying to free it in
533     // this function.
534     pointer = PointerData::AddFreed(pointer);
535     if (pointer != nullptr) {
536       if (g_debug->HeaderEnabled()) {
537         pointer = g_debug->GetHeader(pointer)->orig_pointer;
538       }
539       g_dispatch->free(pointer);
540     }
541   } else {
542     g_dispatch->free(free_pointer);
543   }
544 }
545 
debug_free(void * pointer)546 void debug_free(void* pointer) {
547   if (DebugCallsDisabled() || pointer == nullptr) {
548     return g_dispatch->free(pointer);
549   }
550   ScopedConcurrentLock lock;
551   ScopedDisableDebugCalls disable;
552   ScopedBacktraceSignalBlocker blocked;
553 
554   if (g_debug->config().options() & RECORD_ALLOCS) {
555     g_debug->record->AddEntry(new FreeEntry(pointer));
556   }
557 
558   if (!VerifyPointer(pointer, "free")) {
559     return;
560   }
561 
562   InternalFree(pointer);
563 }
564 
debug_memalign(size_t alignment,size_t bytes)565 void* debug_memalign(size_t alignment, size_t bytes) {
566   if (DebugCallsDisabled()) {
567     return g_dispatch->memalign(alignment, bytes);
568   }
569   ScopedConcurrentLock lock;
570   ScopedDisableDebugCalls disable;
571   ScopedBacktraceSignalBlocker blocked;
572 
573   if (bytes == 0) {
574     bytes = 1;
575   }
576 
577   if (bytes > PointerInfoType::MaxSize()) {
578     errno = ENOMEM;
579     return nullptr;
580   }
581 
582   void* pointer;
583   if (g_debug->HeaderEnabled()) {
584     // Make the alignment a power of two.
585     if (!powerof2(alignment)) {
586       alignment = BIONIC_ROUND_UP_POWER_OF_2(alignment);
587     }
588     // Force the alignment to at least MINIMUM_ALIGNMENT_BYTES to guarantee
589     // that the header is aligned properly.
590     if (alignment < MINIMUM_ALIGNMENT_BYTES) {
591       alignment = MINIMUM_ALIGNMENT_BYTES;
592     }
593 
594     // We don't have any idea what the natural alignment of
595     // the underlying native allocator is, so we always need to
596     // over allocate.
597     size_t real_size = alignment + bytes + g_debug->extra_bytes();
598     if (real_size < bytes) {
599       // Overflow.
600       errno = ENOMEM;
601       return nullptr;
602     }
603 
604     pointer = g_dispatch->malloc(real_size);
605     if (pointer == nullptr) {
606       return nullptr;
607     }
608 
609     uintptr_t value = reinterpret_cast<uintptr_t>(pointer) + g_debug->pointer_offset();
610     // Now align the pointer.
611     value += (-value % alignment);
612 
613     Header* header = g_debug->GetHeader(reinterpret_cast<void*>(value));
614     pointer = InitHeader(header, pointer, bytes);
615   } else {
616     size_t real_size = bytes + g_debug->extra_bytes();
617     if (real_size < bytes) {
618       // Overflow.
619       errno = ENOMEM;
620       return nullptr;
621     }
622     pointer = g_dispatch->memalign(alignment, real_size);
623   }
624 
625   if (pointer != nullptr) {
626     if (g_debug->TrackPointers()) {
627       PointerData::Add(pointer, bytes);
628     }
629 
630     if (g_debug->config().options() & FILL_ON_ALLOC) {
631       size_t bytes = InternalMallocUsableSize(pointer);
632       size_t fill_bytes = g_debug->config().fill_on_alloc_bytes();
633       bytes = (bytes < fill_bytes) ? bytes : fill_bytes;
634       memset(pointer, g_debug->config().fill_alloc_value(), bytes);
635     }
636 
637     if (g_debug->config().options() & RECORD_ALLOCS) {
638       g_debug->record->AddEntry(new MemalignEntry(pointer, bytes, alignment));
639     }
640   }
641 
642   return pointer;
643 }
644 
debug_realloc(void * pointer,size_t bytes)645 void* debug_realloc(void* pointer, size_t bytes) {
646   if (DebugCallsDisabled()) {
647     return g_dispatch->realloc(pointer, bytes);
648   }
649   ScopedConcurrentLock lock;
650   ScopedDisableDebugCalls disable;
651   ScopedBacktraceSignalBlocker blocked;
652 
653   if (pointer == nullptr) {
654     pointer = InternalMalloc(bytes);
655     if (g_debug->config().options() & RECORD_ALLOCS) {
656       g_debug->record->AddEntry(new ReallocEntry(pointer, bytes, nullptr));
657     }
658     return pointer;
659   }
660 
661   if (!VerifyPointer(pointer, "realloc")) {
662     return nullptr;
663   }
664 
665   if (bytes == 0) {
666     if (g_debug->config().options() & RECORD_ALLOCS) {
667       g_debug->record->AddEntry(new ReallocEntry(nullptr, bytes, pointer));
668     }
669 
670     InternalFree(pointer);
671     return nullptr;
672   }
673 
674   size_t real_size = bytes;
675   if (g_debug->config().options() & EXPAND_ALLOC) {
676     real_size += g_debug->config().expand_alloc_bytes();
677     if (real_size < bytes) {
678       // Overflow.
679       errno = ENOMEM;
680       return nullptr;
681     }
682   }
683 
684   if (bytes > PointerInfoType::MaxSize()) {
685     errno = ENOMEM;
686     return nullptr;
687   }
688 
689   void* new_pointer;
690   size_t prev_size;
691   if (g_debug->HeaderEnabled()) {
692     // Same size, do nothing.
693     Header* header = g_debug->GetHeader(pointer);
694     if (real_size == header->size) {
695       if (g_debug->TrackPointers()) {
696         // Remove and re-add so that the backtrace is updated.
697         PointerData::Remove(pointer);
698         PointerData::Add(pointer, real_size);
699       }
700       return pointer;
701     }
702 
703     // Allocation is shrinking.
704     if (real_size < header->usable_size) {
705       header->size = real_size;
706       if (g_debug->config().options() & REAR_GUARD) {
707         // Don't bother allocating a smaller pointer in this case, simply
708         // change the header usable_size and reset the rear guard.
709         header->usable_size = header->size;
710         memset(g_debug->GetRearGuard(header), g_debug->config().rear_guard_value(),
711                g_debug->config().rear_guard_bytes());
712       }
713       if (g_debug->TrackPointers()) {
714         // Remove and re-add so that the backtrace is updated.
715         PointerData::Remove(pointer);
716         PointerData::Add(pointer, real_size);
717       }
718       return pointer;
719     }
720 
721     // Allocate the new size.
722     new_pointer = InternalMalloc(bytes);
723     if (new_pointer == nullptr) {
724       errno = ENOMEM;
725       return nullptr;
726     }
727 
728     prev_size = header->usable_size;
729     memcpy(new_pointer, pointer, prev_size);
730     InternalFree(pointer);
731   } else {
732     if (g_debug->TrackPointers()) {
733       PointerData::Remove(pointer);
734     }
735 
736     prev_size = g_dispatch->malloc_usable_size(pointer);
737     new_pointer = g_dispatch->realloc(pointer, real_size);
738     if (new_pointer == nullptr) {
739       return nullptr;
740     }
741 
742     if (g_debug->TrackPointers()) {
743       PointerData::Add(new_pointer, real_size);
744     }
745   }
746 
747   if (g_debug->config().options() & FILL_ON_ALLOC) {
748     size_t bytes = InternalMallocUsableSize(new_pointer);
749     if (bytes > g_debug->config().fill_on_alloc_bytes()) {
750       bytes = g_debug->config().fill_on_alloc_bytes();
751     }
752     if (bytes > prev_size) {
753       memset(reinterpret_cast<void*>(reinterpret_cast<uintptr_t>(new_pointer) + prev_size),
754              g_debug->config().fill_alloc_value(), bytes - prev_size);
755     }
756   }
757 
758   if (g_debug->config().options() & RECORD_ALLOCS) {
759     g_debug->record->AddEntry(new ReallocEntry(new_pointer, bytes, pointer));
760   }
761 
762   return new_pointer;
763 }
764 
debug_calloc(size_t nmemb,size_t bytes)765 void* debug_calloc(size_t nmemb, size_t bytes) {
766   if (DebugCallsDisabled()) {
767     return g_dispatch->calloc(nmemb, bytes);
768   }
769   ScopedConcurrentLock lock;
770   ScopedDisableDebugCalls disable;
771   ScopedBacktraceSignalBlocker blocked;
772 
773   size_t size;
774   if (__builtin_mul_overflow(nmemb, bytes, &size)) {
775     // Overflow
776     errno = ENOMEM;
777     return nullptr;
778   }
779 
780   if (size == 0) {
781     size = 1;
782   }
783 
784   size_t real_size;
785   if (__builtin_add_overflow(size, g_debug->extra_bytes(), &real_size)) {
786     // Overflow.
787     errno = ENOMEM;
788     return nullptr;
789   }
790 
791   if (real_size > PointerInfoType::MaxSize()) {
792     errno = ENOMEM;
793     return nullptr;
794   }
795 
796   void* pointer;
797   if (g_debug->HeaderEnabled()) {
798     // Need to guarantee the alignment of the header.
799     Header* header =
800         reinterpret_cast<Header*>(g_dispatch->memalign(MINIMUM_ALIGNMENT_BYTES, real_size));
801     if (header == nullptr) {
802       return nullptr;
803     }
804     memset(header, 0, g_dispatch->malloc_usable_size(header));
805     pointer = InitHeader(header, header, size);
806   } else {
807     pointer = g_dispatch->calloc(1, real_size);
808   }
809 
810   if (g_debug->config().options() & RECORD_ALLOCS) {
811     g_debug->record->AddEntry(new CallocEntry(pointer, bytes, nmemb));
812   }
813 
814   if (pointer != nullptr && g_debug->TrackPointers()) {
815     PointerData::Add(pointer, size);
816   }
817   return pointer;
818 }
819 
debug_mallinfo()820 struct mallinfo debug_mallinfo() {
821   return g_dispatch->mallinfo();
822 }
823 
debug_mallopt(int param,int value)824 int debug_mallopt(int param, int value) {
825   return g_dispatch->mallopt(param, value);
826 }
827 
debug_malloc_info(int options,FILE * fp)828 int debug_malloc_info(int options, FILE* fp) {
829   if (DebugCallsDisabled() || !g_debug->TrackPointers()) {
830     return g_dispatch->malloc_info(options, fp);
831   }
832 
833   // Make sure any pending output is written to the file.
834   fflush(fp);
835 
836   ScopedConcurrentLock lock;
837   ScopedDisableDebugCalls disable;
838   ScopedBacktraceSignalBlocker blocked;
839 
840   // Avoid any issues where allocations are made that will be freed
841   // in the fclose.
842   int fd = fileno(fp);
843   MallocXmlElem root(fd, "malloc", "version=\"debug-malloc-1\"");
844   std::vector<ListInfoType> list;
845   PointerData::GetAllocList(&list);
846 
847   size_t alloc_num = 0;
848   for (size_t i = 0; i < list.size(); i++) {
849     MallocXmlElem alloc(fd, "allocation", "nr=\"%zu\"", alloc_num);
850 
851     size_t total = 1;
852     size_t size = list[i].size;
853     while (i < list.size() - 1 && list[i + 1].size == size) {
854       i++;
855       total++;
856     }
857     MallocXmlElem(fd, "size").Contents("%zu", list[i].size);
858     MallocXmlElem(fd, "total").Contents("%zu", total);
859     alloc_num++;
860   }
861   return 0;
862 }
863 
debug_aligned_alloc(size_t alignment,size_t size)864 void* debug_aligned_alloc(size_t alignment, size_t size) {
865   if (DebugCallsDisabled()) {
866     return g_dispatch->aligned_alloc(alignment, size);
867   }
868   if (!powerof2(alignment) || (size % alignment) != 0) {
869     errno = EINVAL;
870     return nullptr;
871   }
872   return debug_memalign(alignment, size);
873 }
874 
debug_posix_memalign(void ** memptr,size_t alignment,size_t size)875 int debug_posix_memalign(void** memptr, size_t alignment, size_t size) {
876   if (DebugCallsDisabled()) {
877     return g_dispatch->posix_memalign(memptr, alignment, size);
878   }
879 
880   if (alignment < sizeof(void*) || !powerof2(alignment)) {
881     return EINVAL;
882   }
883   int saved_errno = errno;
884   *memptr = debug_memalign(alignment, size);
885   errno = saved_errno;
886   return (*memptr != nullptr) ? 0 : ENOMEM;
887 }
888 
debug_malloc_iterate(uintptr_t base,size_t size,void (* callback)(uintptr_t,size_t,void *),void * arg)889 int debug_malloc_iterate(uintptr_t base, size_t size, void (*callback)(uintptr_t, size_t, void*),
890                   void* arg) {
891   ScopedConcurrentLock lock;
892   if (g_debug->TrackPointers()) {
893     // Since malloc is disabled, don't bother acquiring any locks.
894     for (auto it = PointerData::begin(); it != PointerData::end(); ++it) {
895       callback(it->first, InternalMallocUsableSize(reinterpret_cast<void*>(it->first)), arg);
896     }
897     return 0;
898   }
899 
900   // An option that adds a header will add pointer tracking, so no need to
901   // check if headers are enabled.
902   return g_dispatch->malloc_iterate(base, size, callback, arg);
903 }
904 
debug_malloc_disable()905 void debug_malloc_disable() {
906   ScopedConcurrentLock lock;
907   g_dispatch->malloc_disable();
908   if (g_debug->pointer) {
909     g_debug->pointer->PrepareFork();
910   }
911 }
912 
debug_malloc_enable()913 void debug_malloc_enable() {
914   ScopedConcurrentLock lock;
915   if (g_debug->pointer) {
916     g_debug->pointer->PostForkParent();
917   }
918   g_dispatch->malloc_enable();
919 }
920 
debug_malloc_backtrace(void * pointer,uintptr_t * frames,size_t max_frames)921 ssize_t debug_malloc_backtrace(void* pointer, uintptr_t* frames, size_t max_frames) {
922   if (DebugCallsDisabled() || pointer == nullptr) {
923     return 0;
924   }
925   ScopedConcurrentLock lock;
926   ScopedDisableDebugCalls disable;
927   ScopedBacktraceSignalBlocker blocked;
928 
929   if (!(g_debug->config().options() & BACKTRACE)) {
930     return 0;
931   }
932   pointer = UntagPointer(pointer);
933   return PointerData::GetFrames(pointer, frames, max_frames);
934 }
935 
936 #if defined(HAVE_DEPRECATED_MALLOC_FUNCS)
debug_pvalloc(size_t bytes)937 void* debug_pvalloc(size_t bytes) {
938   if (DebugCallsDisabled()) {
939     return g_dispatch->pvalloc(bytes);
940   }
941 
942   size_t pagesize = getpagesize();
943   size_t size = __BIONIC_ALIGN(bytes, pagesize);
944   if (size < bytes) {
945     // Overflow
946     errno = ENOMEM;
947     return nullptr;
948   }
949   return debug_memalign(pagesize, size);
950 }
951 
debug_valloc(size_t size)952 void* debug_valloc(size_t size) {
953   if (DebugCallsDisabled()) {
954     return g_dispatch->valloc(size);
955   }
956   return debug_memalign(getpagesize(), size);
957 }
958 #endif
959 
960 static std::mutex g_dump_lock;
961 
write_dump(int fd)962 static void write_dump(int fd) {
963   dprintf(fd, "Android Native Heap Dump v1.2\n\n");
964 
965   std::string fingerprint = android::base::GetProperty("ro.build.fingerprint", "unknown");
966   dprintf(fd, "Build fingerprint: '%s'\n\n", fingerprint.c_str());
967 
968   PointerData::DumpLiveToFile(fd);
969 
970   dprintf(fd, "MAPS\n");
971   std::string content;
972   if (!android::base::ReadFileToString("/proc/self/maps", &content)) {
973     dprintf(fd, "Could not open /proc/self/maps\n");
974   } else {
975     dprintf(fd, "%s", content.c_str());
976   }
977   dprintf(fd, "END\n");
978 }
979 
debug_write_malloc_leak_info(FILE * fp)980 bool debug_write_malloc_leak_info(FILE* fp) {
981   // Make sure any pending output is written to the file.
982   fflush(fp);
983 
984   ScopedConcurrentLock lock;
985   ScopedDisableDebugCalls disable;
986   ScopedBacktraceSignalBlocker blocked;
987 
988   std::lock_guard<std::mutex> guard(g_dump_lock);
989 
990   if (!(g_debug->config().options() & BACKTRACE)) {
991     return false;
992   }
993 
994   write_dump(fileno(fp));
995 
996   return true;
997 }
998 
debug_dump_heap(const char * file_name)999 void debug_dump_heap(const char* file_name) {
1000   ScopedConcurrentLock lock;
1001   ScopedDisableDebugCalls disable;
1002   ScopedBacktraceSignalBlocker blocked;
1003 
1004   std::lock_guard<std::mutex> guard(g_dump_lock);
1005 
1006   int fd = open(file_name, O_RDWR | O_CREAT | O_NOFOLLOW | O_TRUNC | O_CLOEXEC, 0644);
1007   if (fd == -1) {
1008     error_log("Unable to create file: %s", file_name);
1009     return;
1010   }
1011 
1012   error_log("Dumping to file: %s\n", file_name);
1013   write_dump(fd);
1014   close(fd);
1015 }
1016