1/*
2 * Copyright 2014-present Facebook, Inc.
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/portability/Config.h>
24
25#if FOLLY_DETAIL_HAVE_DEMANGLE_H
26
27#include <cxxabi.h>
28
29#endif
30
31namespace folly {
32
33#if FOLLY_DETAIL_HAVE_DEMANGLE_H
34
35fbstring demangle(const char* name) {
36#ifdef FOLLY_DEMANGLE_MAX_SYMBOL_SIZE
37 // GCC's __cxa_demangle() uses on-stack data structures for the
38 // parser state which are linear in the number of components of the
39 // symbol. For extremely long symbols, this can cause a stack
40 // overflow. We set an arbitrary symbol length limit above which we
41 // just return the mangled name.
42 size_t mangledLen = strlen(name);
43 if (mangledLen > FOLLY_DEMANGLE_MAX_SYMBOL_SIZE) {
44 return fbstring(name, mangledLen);
45 }
46#endif
47
48 int status;
49 size_t len = 0;
50 // malloc() memory for the demangled type name
51 char* demangled = abi::__cxa_demangle(name, nullptr, &len, &status);
52 if (status != 0) {
53 return name;
54 }
55 // len is the length of the buffer (including NUL terminator and maybe
56 // other junk)
57 return fbstring(demangled, strlen(demangled), len, AcquireMallocatedString());
58}
59
60namespace {
61
62struct DemangleBuf {
63 char* dest;
64 size_t remaining;
65 size_t total;
66};
67
68void demangleCallback(const char* str, size_t size, void* p) {
69 DemangleBuf* buf = static_cast<DemangleBuf*>(p);
70 size_t n = std::min(buf->remaining, size);
71 memcpy(buf->dest, str, n);
72 buf->dest += n;
73 buf->remaining -= n;
74 buf->total += size;
75}
76
77} // namespace
78
79size_t demangle(const char* name, char* out, size_t outSize) {
80#ifdef FOLLY_DEMANGLE_MAX_SYMBOL_SIZE
81 size_t mangledLen = strlen(name);
82 if (mangledLen > FOLLY_DEMANGLE_MAX_SYMBOL_SIZE) {
83 if (outSize) {
84 size_t n = std::min(mangledLen, outSize - 1);
85 memcpy(out, name, n);
86 out[n] = '\0';
87 }
88 return mangledLen;
89 }
90#endif
91
92 DemangleBuf dbuf;
93 dbuf.dest = out;
94 dbuf.remaining = outSize ? outSize - 1 : 0; // leave room for null term
95 dbuf.total = 0;
96
97 // Unlike most library functions, this returns 1 on success and 0 on failure
98 int status =
99 detail::cplus_demangle_v3_callback_wrapper(name, demangleCallback, &dbuf);
100 if (status == 0) { // failed, return original
101 return folly::strlcpy(out, name, outSize);
102 }
103 if (outSize != 0) {
104 *dbuf.dest = '\0';
105 }
106 return dbuf.total;
107}
108
109#else
110
111fbstring demangle(const char* name) {
112 return name;
113}
114
115size_t demangle(const char* name, char* out, size_t outSize) {
116 return folly::strlcpy(out, name, outSize);
117}
118
119#endif
120
121size_t strlcpy(char* dest, const char* const src, size_t size) {
122 size_t len = strlen(src);
123 if (size != 0) {
124 size_t n = std::min(len, size - 1); // always null terminate!
125 memcpy(dest, src, n);
126 dest[n] = '\0';
127 }
128 return len;
129}
130
131} // namespace folly
132