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      1 //===-- asan_debugging.cc -------------------------------------------------===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 //
     10 // This file is a part of AddressSanitizer, an address sanity checker.
     11 //
     12 // This file contains various functions that are generally useful to call when
     13 // using a debugger (LLDB, GDB).
     14 //===----------------------------------------------------------------------===//
     15 
     16 #include "asan_allocator.h"
     17 #include "asan_flags.h"
     18 #include "asan_internal.h"
     19 #include "asan_mapping.h"
     20 #include "asan_report.h"
     21 #include "asan_thread.h"
     22 
     23 namespace __asan {
     24 
     25 void GetInfoForStackVar(uptr addr, AddressDescription *descr, AsanThread *t) {
     26   descr->name[0] = 0;
     27   descr->region_address = 0;
     28   descr->region_size = 0;
     29   descr->region_kind = "stack";
     30 
     31   AsanThread::StackFrameAccess access;
     32   if (!t->GetStackFrameAccessByAddr(addr, &access))
     33     return;
     34   InternalMmapVector<StackVarDescr> vars(16);
     35   if (!ParseFrameDescription(access.frame_descr, &vars)) {
     36     return;
     37   }
     38 
     39   for (uptr i = 0; i < vars.size(); i++) {
     40     if (access.offset <= vars[i].beg + vars[i].size) {
     41       internal_strncat(descr->name, vars[i].name_pos,
     42                        Min(descr->name_size, vars[i].name_len));
     43       descr->region_address = addr - (access.offset - vars[i].beg);
     44       descr->region_size = vars[i].size;
     45       return;
     46     }
     47   }
     48 }
     49 
     50 void GetInfoForHeapAddress(uptr addr, AddressDescription *descr) {
     51   AsanChunkView chunk = FindHeapChunkByAddress(addr);
     52 
     53   descr->name[0] = 0;
     54   descr->region_address = 0;
     55   descr->region_size = 0;
     56 
     57   if (!chunk.IsValid()) {
     58     descr->region_kind = "heap-invalid";
     59     return;
     60   }
     61 
     62   descr->region_address = chunk.Beg();
     63   descr->region_size = chunk.UsedSize();
     64   descr->region_kind = "heap";
     65 }
     66 
     67 void AsanLocateAddress(uptr addr, AddressDescription *descr) {
     68   if (DescribeAddressIfShadow(addr, descr, /* print */ false)) {
     69     return;
     70   }
     71   if (GetInfoForAddressIfGlobal(addr, descr)) {
     72     return;
     73   }
     74   asanThreadRegistry().Lock();
     75   AsanThread *thread = FindThreadByStackAddress(addr);
     76   asanThreadRegistry().Unlock();
     77   if (thread) {
     78     GetInfoForStackVar(addr, descr, thread);
     79     return;
     80   }
     81   GetInfoForHeapAddress(addr, descr);
     82 }
     83 
     84 static uptr AsanGetStack(uptr addr, uptr *trace, u32 size, u32 *thread_id,
     85                          bool alloc_stack) {
     86   AsanChunkView chunk = FindHeapChunkByAddress(addr);
     87   if (!chunk.IsValid()) return 0;
     88 
     89   StackTrace stack(nullptr, 0);
     90   if (alloc_stack) {
     91     if (chunk.AllocTid() == kInvalidTid) return 0;
     92     stack = chunk.GetAllocStack();
     93     if (thread_id) *thread_id = chunk.AllocTid();
     94   } else {
     95     if (chunk.FreeTid() == kInvalidTid) return 0;
     96     stack = chunk.GetFreeStack();
     97     if (thread_id) *thread_id = chunk.FreeTid();
     98   }
     99 
    100   if (trace && size) {
    101     size = Min(size, Min(stack.size, kStackTraceMax));
    102     for (uptr i = 0; i < size; i++)
    103       trace[i] = StackTrace::GetPreviousInstructionPc(stack.trace[i]);
    104 
    105     return size;
    106   }
    107 
    108   return 0;
    109 }
    110 
    111 } // namespace __asan
    112 
    113 using namespace __asan;
    114 
    115 SANITIZER_INTERFACE_ATTRIBUTE
    116 const char *__asan_locate_address(uptr addr, char *name, uptr name_size,
    117                                   uptr *region_address, uptr *region_size) {
    118   AddressDescription descr = { name, name_size, 0, 0, nullptr };
    119   AsanLocateAddress(addr, &descr);
    120   if (region_address) *region_address = descr.region_address;
    121   if (region_size) *region_size = descr.region_size;
    122   return descr.region_kind;
    123 }
    124 
    125 SANITIZER_INTERFACE_ATTRIBUTE
    126 uptr __asan_get_alloc_stack(uptr addr, uptr *trace, uptr size, u32 *thread_id) {
    127   return AsanGetStack(addr, trace, size, thread_id, /* alloc_stack */ true);
    128 }
    129 
    130 SANITIZER_INTERFACE_ATTRIBUTE
    131 uptr __asan_get_free_stack(uptr addr, uptr *trace, uptr size, u32 *thread_id) {
    132   return AsanGetStack(addr, trace, size, thread_id, /* alloc_stack */ false);
    133 }
    134 
    135 SANITIZER_INTERFACE_ATTRIBUTE
    136 void __asan_get_shadow_mapping(uptr *shadow_scale, uptr *shadow_offset) {
    137   if (shadow_scale)
    138     *shadow_scale = SHADOW_SCALE;
    139   if (shadow_offset)
    140     *shadow_offset = SHADOW_OFFSET;
    141 }
    142