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#ifndef _GNU_SOURCE
#define _GNU_SOURCE
#endif
#ifndef CHANGE_SRC_ACTUAL_FUNCTION_H_
#define CHANGE_SRC_ACTUAL_FUNCTION_H_
#include <dlfcn.h>
#include <sys/mman.h>
#include <sys/uio.h>
#include <memory>
#include <cstring>
namespace {
template <class Result, typename... Arguments>
using function_ptr = Result(*)(Arguments...);
template <typename FunctionPtr>
FunctionPtr get_actual_function(const std::string& symbol_name) {
const void* symbol_address{ dlsym(RTLD_NEXT, symbol_name.c_str()) };
FunctionPtr actual_function{};
std::memcpy(&actual_function, &symbol_address, sizeof(symbol_address));
return actual_function;
}
}
namespace actual {
static auto write = get_actual_function<
function_ptr<ssize_t, int, const void*, size_t>
>("write");
static auto writev = get_actual_function<
function_ptr<ssize_t, int, const iovec*, int>
>("writev");
static auto rename = get_actual_function<
function_ptr<int, const char*, const char*>
>("rename");
static auto rmdir = get_actual_function<
function_ptr<int, const char*>
>("rmdir");
static auto unlink = get_actual_function<
function_ptr<int, const char*>
>("unlink");
static auto unlinkat = get_actual_function<
function_ptr<int, int, const char*, int>
>("unlinkat");
static auto mmap = get_actual_function<
function_ptr<void*, void*, size_t, int, int, int, off_t>
>("mmap");
}
#endif // CHANGE_SRC_ACTUAL_FUNCTION_H_
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