135 lines
3.5 KiB
C++
135 lines
3.5 KiB
C++
//===- Unix/DynamicLibrary.cpp - Unix DL Implementation ---------*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This file provides the UNIX specific implementation of DynamicLibrary.
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//
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//===----------------------------------------------------------------------===//
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#if defined(HAVE_DLFCN_H) && defined(HAVE_DLOPEN)
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#include <dlfcn.h>
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DynamicLibrary::HandleSet::~HandleSet() {
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// Close the libraries in reverse order.
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for (void *Handle : llvm::reverse(Handles))
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::dlclose(Handle);
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if (Process)
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::dlclose(Process);
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// llvm_shutdown called, Return to default
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DynamicLibrary::SearchOrder = DynamicLibrary::SO_Linker;
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}
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void *DynamicLibrary::HandleSet::DLOpen(const char *File, std::string *Err) {
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void *Handle = ::dlopen(File, RTLD_LAZY|RTLD_GLOBAL);
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if (!Handle) {
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if (Err) *Err = ::dlerror();
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return &DynamicLibrary::Invalid;
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}
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#ifdef __CYGWIN__
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// Cygwin searches symbols only in the main
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// with the handle of dlopen(NULL, RTLD_GLOBAL).
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if (!File)
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Handle = RTLD_DEFAULT;
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#endif
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return Handle;
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}
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void DynamicLibrary::HandleSet::DLClose(void *Handle) {
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::dlclose(Handle);
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}
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void *DynamicLibrary::HandleSet::DLSym(void *Handle, const char *Symbol) {
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return ::dlsym(Handle, Symbol);
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}
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#else // !HAVE_DLOPEN
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DynamicLibrary::HandleSet::~HandleSet() {}
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void *DynamicLibrary::HandleSet::DLOpen(const char *File, std::string *Err) {
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if (Err) *Err = "dlopen() not supported on this platform";
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return &Invalid;
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}
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void DynamicLibrary::HandleSet::DLClose(void *Handle) {
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}
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void *DynamicLibrary::HandleSet::DLSym(void *Handle, const char *Symbol) {
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return nullptr;
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}
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#endif
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// Must declare the symbols in the global namespace.
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static void *DoSearch(const char* SymbolName) {
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#define EXPLICIT_SYMBOL(SYM) \
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extern void *SYM; if (!strcmp(SymbolName, #SYM)) return (void*)&SYM
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// If this is darwin, it has some funky issues, try to solve them here. Some
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// important symbols are marked 'private external' which doesn't allow
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// SearchForAddressOfSymbol to find them. As such, we special case them here,
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// there is only a small handful of them.
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#ifdef __APPLE__
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{
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// __eprintf is sometimes used for assert() handling on x86.
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//
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// FIXME: Currently disabled when using Clang, as we don't always have our
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// runtime support libraries available.
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#ifndef __clang__
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#ifdef __i386__
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EXPLICIT_SYMBOL(__eprintf);
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#endif
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#endif
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}
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#endif
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#ifdef __CYGWIN__
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{
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EXPLICIT_SYMBOL(_alloca);
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EXPLICIT_SYMBOL(__main);
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}
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#endif
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#undef EXPLICIT_SYMBOL
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// This macro returns the address of a well-known, explicit symbol
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#define EXPLICIT_SYMBOL(SYM) \
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if (!strcmp(SymbolName, #SYM)) return &SYM
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// Under glibc we have a weird situation. The stderr/out/in symbols are both
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// macros and global variables because of standards requirements. So, we
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// boldly use the EXPLICIT_SYMBOL macro without checking for a #define first.
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#if defined(__GLIBC__)
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{
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EXPLICIT_SYMBOL(stderr);
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EXPLICIT_SYMBOL(stdout);
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EXPLICIT_SYMBOL(stdin);
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}
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#else
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// For everything else, we want to check to make sure the symbol isn't defined
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// as a macro before using EXPLICIT_SYMBOL.
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{
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#ifndef stdin
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EXPLICIT_SYMBOL(stdin);
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#endif
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#ifndef stdout
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EXPLICIT_SYMBOL(stdout);
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#endif
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#ifndef stderr
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EXPLICIT_SYMBOL(stderr);
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#endif
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}
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#endif
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#undef EXPLICIT_SYMBOL
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return nullptr;
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}
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