1 | /* |
2 | * Copyright (c) Facebook, Inc. and its affiliates. |
3 | * |
4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
5 | * you may not use this file except in compliance with the License. |
6 | * You may obtain a copy of the License at |
7 | * |
8 | * http://www.apache.org/licenses/LICENSE-2.0 |
9 | * |
10 | * Unless required by applicable law or agreed to in writing, software |
11 | * distributed under the License is distributed on an "AS IS" BASIS, |
12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
13 | * See the License for the specific language governing permissions and |
14 | * limitations under the License. |
15 | */ |
16 | |
17 | #include <folly/Demangle.h> |
18 | |
19 | #include <algorithm> |
20 | #include <cstring> |
21 | |
22 | #include <folly/detail/Demangle.h> |
23 | #include <folly/lang/CString.h> |
24 | #include <folly/portability/Config.h> |
25 | |
26 | #if FOLLY_DETAIL_HAVE_DEMANGLE_H |
27 | |
28 | #include <cxxabi.h> |
29 | |
30 | #endif |
31 | |
32 | namespace folly { |
33 | |
34 | #if FOLLY_DETAIL_HAVE_DEMANGLE_H |
35 | |
36 | fbstring demangle(const char* name) { |
37 | if (!name) { |
38 | return fbstring(); |
39 | } |
40 | #ifdef FOLLY_DEMANGLE_MAX_SYMBOL_SIZE |
41 | // GCC's __cxa_demangle() uses on-stack data structures for the |
42 | // parser state which are linear in the number of components of the |
43 | // symbol. For extremely long symbols, this can cause a stack |
44 | // overflow. We set an arbitrary symbol length limit above which we |
45 | // just return the mangled name. |
46 | size_t mangledLen = strlen(name); |
47 | if (mangledLen > FOLLY_DEMANGLE_MAX_SYMBOL_SIZE) { |
48 | return fbstring(name, mangledLen); |
49 | } |
50 | #endif |
51 | |
52 | int status; |
53 | size_t len = 0; |
54 | // malloc() memory for the demangled type name |
55 | char* demangled = abi::__cxa_demangle(name, nullptr, &len, &status); |
56 | if (status != 0) { |
57 | return name; |
58 | } |
59 | // len is the length of the buffer (including NUL terminator and maybe |
60 | // other junk) |
61 | return fbstring(demangled, strlen(demangled), len, AcquireMallocatedString()); |
62 | } |
63 | |
64 | namespace { |
65 | |
66 | struct DemangleBuf { |
67 | char* dest; |
68 | size_t remaining; |
69 | size_t total; |
70 | }; |
71 | |
72 | void demangleCallback(const char* str, size_t size, void* p) { |
73 | DemangleBuf* buf = static_cast<DemangleBuf*>(p); |
74 | size_t n = std::min(buf->remaining, size); |
75 | memcpy(buf->dest, str, n); |
76 | buf->dest += n; |
77 | buf->remaining -= n; |
78 | buf->total += size; |
79 | } |
80 | |
81 | } // namespace |
82 | |
83 | size_t demangle(const char* name, char* out, size_t outSize) { |
84 | #ifdef FOLLY_DEMANGLE_MAX_SYMBOL_SIZE |
85 | size_t mangledLen = strlen(name); |
86 | if (mangledLen > FOLLY_DEMANGLE_MAX_SYMBOL_SIZE) { |
87 | if (outSize) { |
88 | size_t n = std::min(mangledLen, outSize - 1); |
89 | memcpy(out, name, n); |
90 | out[n] = '\0'; |
91 | } |
92 | return mangledLen; |
93 | } |
94 | #endif |
95 | |
96 | DemangleBuf dbuf; |
97 | dbuf.dest = out; |
98 | dbuf.remaining = outSize ? outSize - 1 : 0; // leave room for null term |
99 | dbuf.total = 0; |
100 | |
101 | // Unlike most library functions, this returns 1 on success and 0 on failure |
102 | int status = |
103 | detail::cplus_demangle_v3_callback_wrapper(name, demangleCallback, &dbuf); |
104 | if (status == 0) { // failed, return original |
105 | return folly::strlcpy(out, name, outSize); |
106 | } |
107 | if (outSize != 0) { |
108 | *dbuf.dest = '\0'; |
109 | } |
110 | return dbuf.total; |
111 | } |
112 | |
113 | #else |
114 | |
115 | fbstring demangle(const char* name) { |
116 | return name; |
117 | } |
118 | |
119 | size_t demangle(const char* name, char* out, size_t outSize) { |
120 | return folly::strlcpy(out, name, outSize); |
121 | } |
122 | |
123 | #endif |
124 | |
125 | } // namespace folly |
126 | |