1 //===-- asan_debugging.cc -------------------------------------------------===//
2 //
3 // This file is distributed under the University of Illinois Open Source
4 // License. See LICENSE.TXT for details.
5 //
6 //===----------------------------------------------------------------------===//
7 //
8 // This file is a part of AddressSanitizer, an address sanity checker.
9 //
10 // This file contains various functions that are generally useful to call when
11 // using a debugger (LLDB, GDB).
12 //===----------------------------------------------------------------------===//
13
14 #include "asan_allocator.h"
15 #include "asan_descriptions.h"
16 #include "asan_flags.h"
17 #include "asan_internal.h"
18 #include "asan_mapping.h"
19 #include "asan_report.h"
20 #include "asan_thread.h"
21
22 namespace {
23 using namespace __asan;
24
FindInfoForStackVar(uptr addr,const char * frame_descr,uptr offset,char * name,uptr name_size,uptr & region_address,uptr & region_size)25 static void FindInfoForStackVar(uptr addr, const char *frame_descr, uptr offset,
26 char *name, uptr name_size,
27 uptr ®ion_address, uptr ®ion_size) {
28 InternalMmapVector<StackVarDescr> vars;
29 vars.reserve(16);
30 if (!ParseFrameDescription(frame_descr, &vars)) {
31 return;
32 }
33
34 for (uptr i = 0; i < vars.size(); i++) {
35 if (offset <= vars[i].beg + vars[i].size) {
36 // We use name_len + 1 because strlcpy will guarantee a \0 at the end, so
37 // if we're limiting the copy due to name_len, we add 1 to ensure we copy
38 // the whole name and then terminate with '\0'.
39 internal_strlcpy(name, vars[i].name_pos,
40 Min(name_size, vars[i].name_len + 1));
41 region_address = addr - (offset - vars[i].beg);
42 region_size = vars[i].size;
43 return;
44 }
45 }
46 }
47
AsanGetStack(uptr addr,uptr * trace,u32 size,u32 * thread_id,bool alloc_stack)48 uptr AsanGetStack(uptr addr, uptr *trace, u32 size, u32 *thread_id,
49 bool alloc_stack) {
50 AsanChunkView chunk = FindHeapChunkByAddress(addr);
51 if (!chunk.IsValid()) return 0;
52
53 StackTrace stack(nullptr, 0);
54 if (alloc_stack) {
55 if (chunk.AllocTid() == kInvalidTid) return 0;
56 stack = chunk.GetAllocStack();
57 if (thread_id) *thread_id = chunk.AllocTid();
58 } else {
59 if (chunk.FreeTid() == kInvalidTid) return 0;
60 stack = chunk.GetFreeStack();
61 if (thread_id) *thread_id = chunk.FreeTid();
62 }
63
64 if (trace && size) {
65 size = Min(size, Min(stack.size, kStackTraceMax));
66 for (uptr i = 0; i < size; i++)
67 trace[i] = StackTrace::GetPreviousInstructionPc(stack.trace[i]);
68
69 return size;
70 }
71
72 return 0;
73 }
74
75 } // namespace
76
77 SANITIZER_INTERFACE_ATTRIBUTE
__asan_locate_address(uptr addr,char * name,uptr name_size,uptr * region_address_ptr,uptr * region_size_ptr)78 const char *__asan_locate_address(uptr addr, char *name, uptr name_size,
79 uptr *region_address_ptr,
80 uptr *region_size_ptr) {
81 AddressDescription descr(addr);
82 uptr region_address = 0;
83 uptr region_size = 0;
84 const char *region_kind = nullptr;
85 if (name && name_size > 0) name[0] = 0;
86
87 if (auto shadow = descr.AsShadow()) {
88 // region_{address,size} are already 0
89 switch (shadow->kind) {
90 case kShadowKindLow:
91 region_kind = "low shadow";
92 break;
93 case kShadowKindGap:
94 region_kind = "shadow gap";
95 break;
96 case kShadowKindHigh:
97 region_kind = "high shadow";
98 break;
99 }
100 } else if (auto heap = descr.AsHeap()) {
101 region_kind = "heap";
102 region_address = heap->chunk_access.chunk_begin;
103 region_size = heap->chunk_access.chunk_size;
104 } else if (auto stack = descr.AsStack()) {
105 region_kind = "stack";
106 if (!stack->frame_descr) {
107 // region_{address,size} are already 0
108 } else {
109 FindInfoForStackVar(addr, stack->frame_descr, stack->offset, name,
110 name_size, region_address, region_size);
111 }
112 } else if (auto global = descr.AsGlobal()) {
113 region_kind = "global";
114 auto &g = global->globals[0];
115 internal_strlcpy(name, g.name, name_size);
116 region_address = g.beg;
117 region_size = g.size;
118 } else {
119 // region_{address,size} are already 0
120 region_kind = "heap-invalid";
121 }
122
123 CHECK(region_kind);
124 if (region_address_ptr) *region_address_ptr = region_address;
125 if (region_size_ptr) *region_size_ptr = region_size;
126 return region_kind;
127 }
128
129 SANITIZER_INTERFACE_ATTRIBUTE
__asan_get_alloc_stack(uptr addr,uptr * trace,uptr size,u32 * thread_id)130 uptr __asan_get_alloc_stack(uptr addr, uptr *trace, uptr size, u32 *thread_id) {
131 return AsanGetStack(addr, trace, size, thread_id, /* alloc_stack */ true);
132 }
133
134 SANITIZER_INTERFACE_ATTRIBUTE
__asan_get_free_stack(uptr addr,uptr * trace,uptr size,u32 * thread_id)135 uptr __asan_get_free_stack(uptr addr, uptr *trace, uptr size, u32 *thread_id) {
136 return AsanGetStack(addr, trace, size, thread_id, /* alloc_stack */ false);
137 }
138
139 SANITIZER_INTERFACE_ATTRIBUTE
__asan_get_shadow_mapping(uptr * shadow_scale,uptr * shadow_offset)140 void __asan_get_shadow_mapping(uptr *shadow_scale, uptr *shadow_offset) {
141 if (shadow_scale)
142 *shadow_scale = SHADOW_SCALE;
143 if (shadow_offset)
144 *shadow_offset = SHADOW_OFFSET;
145 }
146