1 //===-- DynamicLibrary.cpp - Runtime link/load libraries --------*- C++ -*-===//
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 implements the operating system DynamicLibrary concept.
11 //
12 // FIXME: This file leaks ExplicitSymbols and OpenedHandles!
13 //
14 //===----------------------------------------------------------------------===//
15
16 #include "llvm/Support/DynamicLibrary.h"
17 #include "llvm-c/Support.h"
18 #include "llvm/ADT/DenseSet.h"
19 #include "llvm/ADT/StringMap.h"
20 #include "llvm/Config/config.h"
21 #include "llvm/Support/ManagedStatic.h"
22 #include "llvm/Support/Mutex.h"
23 #include <cstdio>
24 #include <cstring>
25
26 // Collection of symbol name/value pairs to be searched prior to any libraries.
27 static llvm::ManagedStatic<llvm::StringMap<void *> > ExplicitSymbols;
28 static llvm::ManagedStatic<llvm::sys::SmartMutex<true> > SymbolsMutex;
29
AddSymbol(StringRef symbolName,void * symbolValue)30 void llvm::sys::DynamicLibrary::AddSymbol(StringRef symbolName,
31 void *symbolValue) {
32 SmartScopedLock<true> lock(*SymbolsMutex);
33 (*ExplicitSymbols)[symbolName] = symbolValue;
34 }
35
36 char llvm::sys::DynamicLibrary::Invalid = 0;
37
38 #ifdef LLVM_ON_WIN32
39
40 #include "Windows/DynamicLibrary.inc"
41
42 #else
43
44 #if HAVE_DLFCN_H
45 #include <dlfcn.h>
46 using namespace llvm;
47 using namespace llvm::sys;
48
49 //===----------------------------------------------------------------------===//
50 //=== WARNING: Implementation here must contain only TRULY operating system
51 //=== independent code.
52 //===----------------------------------------------------------------------===//
53
54 static DenseSet<void *> *OpenedHandles = nullptr;
55
getPermanentLibrary(const char * filename,std::string * errMsg)56 DynamicLibrary DynamicLibrary::getPermanentLibrary(const char *filename,
57 std::string *errMsg) {
58 SmartScopedLock<true> lock(*SymbolsMutex);
59
60 void *handle = dlopen(filename, RTLD_LAZY|RTLD_GLOBAL);
61 if (!handle) {
62 if (errMsg) *errMsg = dlerror();
63 return DynamicLibrary();
64 }
65
66 #ifdef __CYGWIN__
67 // Cygwin searches symbols only in the main
68 // with the handle of dlopen(NULL, RTLD_GLOBAL).
69 if (!filename)
70 handle = RTLD_DEFAULT;
71 #endif
72
73 if (!OpenedHandles)
74 OpenedHandles = new DenseSet<void *>();
75
76 // If we've already loaded this library, dlclose() the handle in order to
77 // keep the internal refcount at +1.
78 if (!OpenedHandles->insert(handle).second)
79 dlclose(handle);
80
81 return DynamicLibrary(handle);
82 }
83
getAddressOfSymbol(const char * symbolName)84 void *DynamicLibrary::getAddressOfSymbol(const char *symbolName) {
85 if (!isValid())
86 return nullptr;
87 return dlsym(Data, symbolName);
88 }
89
90 #else
91
92 using namespace llvm;
93 using namespace llvm::sys;
94
getPermanentLibrary(const char * filename,std::string * errMsg)95 DynamicLibrary DynamicLibrary::getPermanentLibrary(const char *filename,
96 std::string *errMsg) {
97 if (errMsg) *errMsg = "dlopen() not supported on this platform";
98 return DynamicLibrary();
99 }
100
getAddressOfSymbol(const char * symbolName)101 void *DynamicLibrary::getAddressOfSymbol(const char *symbolName) {
102 return NULL;
103 }
104
105 #endif
106
107 namespace llvm {
108 void *SearchForAddressOfSpecialSymbol(const char* symbolName);
109 }
110
SearchForAddressOfSymbol(const char * symbolName)111 void* DynamicLibrary::SearchForAddressOfSymbol(const char *symbolName) {
112 SmartScopedLock<true> Lock(*SymbolsMutex);
113
114 // First check symbols added via AddSymbol().
115 if (ExplicitSymbols.isConstructed()) {
116 StringMap<void *>::iterator i = ExplicitSymbols->find(symbolName);
117
118 if (i != ExplicitSymbols->end())
119 return i->second;
120 }
121
122 #if HAVE_DLFCN_H
123 // Now search the libraries.
124 if (OpenedHandles) {
125 for (DenseSet<void *>::iterator I = OpenedHandles->begin(),
126 E = OpenedHandles->end(); I != E; ++I) {
127 //lt_ptr ptr = lt_dlsym(*I, symbolName);
128 void *ptr = dlsym(*I, symbolName);
129 if (ptr) {
130 return ptr;
131 }
132 }
133 }
134 #endif
135
136 if (void *Result = llvm::SearchForAddressOfSpecialSymbol(symbolName))
137 return Result;
138
139 // This macro returns the address of a well-known, explicit symbol
140 #define EXPLICIT_SYMBOL(SYM) \
141 if (!strcmp(symbolName, #SYM)) return &SYM
142
143 // On linux we have a weird situation. The stderr/out/in symbols are both
144 // macros and global variables because of standards requirements. So, we
145 // boldly use the EXPLICIT_SYMBOL macro without checking for a #define first.
146 #if defined(__linux__) and !defined(__ANDROID__)
147 {
148 EXPLICIT_SYMBOL(stderr);
149 EXPLICIT_SYMBOL(stdout);
150 EXPLICIT_SYMBOL(stdin);
151 }
152 #else
153 // For everything else, we want to check to make sure the symbol isn't defined
154 // as a macro before using EXPLICIT_SYMBOL.
155 {
156 #ifndef stdin
157 EXPLICIT_SYMBOL(stdin);
158 #endif
159 #ifndef stdout
160 EXPLICIT_SYMBOL(stdout);
161 #endif
162 #ifndef stderr
163 EXPLICIT_SYMBOL(stderr);
164 #endif
165 }
166 #endif
167 #undef EXPLICIT_SYMBOL
168
169 return nullptr;
170 }
171
172 #endif // LLVM_ON_WIN32
173
174 //===----------------------------------------------------------------------===//
175 // C API.
176 //===----------------------------------------------------------------------===//
177
LLVMLoadLibraryPermanently(const char * Filename)178 LLVMBool LLVMLoadLibraryPermanently(const char* Filename) {
179 return llvm::sys::DynamicLibrary::LoadLibraryPermanently(Filename);
180 }
181
LLVMSearchForAddressOfSymbol(const char * symbolName)182 void *LLVMSearchForAddressOfSymbol(const char *symbolName) {
183 return llvm::sys::DynamicLibrary::SearchForAddressOfSymbol(symbolName);
184 }
185
LLVMAddSymbol(const char * symbolName,void * symbolValue)186 void LLVMAddSymbol(const char *symbolName, void *symbolValue) {
187 return llvm::sys::DynamicLibrary::AddSymbol(symbolName, symbolValue);
188 }
189
190