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#ifndef _GNU_SOURCE
#define _GNU_SOURCE
#endif
#include <sys/mman.h>
#include <memory>
#include <algorithm>
#include <functional>
#include <unordered_set>
#include "io.h"
#include "utility.h"
static std::unique_ptr<std::unordered_set<std::string>> tracked_files;
static std::unique_ptr<io::FileDescriptorGuard> fd_guard;
static std::unique_ptr<utility::Logger> logger;
template <class Result, typename... Arguments>
std::function<Result(Arguments...)> get_real_function(
const std::string& symbol_name) {
Result (*real_function)(Arguments...) = nullptr;
const void* symbol_address = dlsym(RTLD_NEXT, symbol_name.c_str());
std::memcpy(&real_function, &symbol_address, sizeof(symbol_address));
return std::function<Result(Arguments...)>(real_function);
}
void init() __attribute__ ((constructor));
void init() {
tracked_files = std::make_unique<std::unordered_set<std::string>>();
if ( getenv("CHANGE_LOG_TARGET") != NULL ) {
fd_guard = std::make_unique<io::FileDescriptorGuard>(
getenv("CHANGE_LOG_TARGET")
);
logger = std::make_unique<utility::Logger>(*fd_guard);
} else {
logger = std::make_unique<utility::Logger>(STDERR_FILENO);
}
}
void exit(int status) {
logger->append("exit");
get_real_function<void, int>("exit")(status);
}
bool is_tracked_file(const std::string& file_name) {
return tracked_files->find(file_name) != tracked_files->end();
}
bool track_file(const std::string& file_name) {
return tracked_files->emplace(file_name).second;
}
ssize_t write(int fd, const void* buffer, size_t count) {
static auto real_write = get_real_function<ssize_t, int, const void*, size_t>("write");
if ( io::is_regular_file(fd) ) {
const std::string file_name{ io::get_file_name(fd) };
if ( !is_tracked_file(file_name) ) {
track_file(file_name);
logger->append("wrote to '" + file_name + "'");
}
}
return real_write(fd, buffer, count);
}
int rename(const char* old_path, const char* new_path) {
static auto real_rename = get_real_function<int, const char*, const char*>("rename");
if ( !is_tracked_file(old_path) ) {
track_file(old_path);
}
logger->append("renamed '" + std::string(old_path) + "' to '" + std::string(new_path) + "'");
return real_rename(old_path, new_path);
}
int rmdir(const char* path) {
static auto real_rmdir = get_real_function<int, const char*>("rmdir");
logger->append("removed directory '" + std::string(path) + "'");
return real_rmdir(path);
}
int unlink(const char* path) {
static auto real_unlink = get_real_function<int, const char*>("unlink");
logger->append("removed '" + std::string(path) + "'");
return real_unlink(path);
}
int unlinkat(int dirfd, const char* path, int flags) {
static auto real_unlinkat = get_real_function<int, int, const char*, int>("unlinkat");
if ( dirfd == AT_FDCWD ) {
logger->append("removed '" + std::string(path) + "'");
} else {
logger->append("removed '" + io::get_file_name(dirfd) + path + "'");
}
return real_unlinkat(dirfd, path, flags);
}
void* mmap(void* addr, size_t length, int prot, int flags, int fd, off_t offset) {
static auto real_mmap = get_real_function<void*, void*, size_t, int, int, int, off_t>("mmap");
if ( ( prot & PROT_WRITE ) && io::is_regular_file(fd) ) {
const std::string file_name{ io::get_file_name(fd) };
if ( !is_tracked_file(file_name) ) {
track_file(file_name);
logger->append("mmap '" + file_name + "'");
}
}
return real_mmap(addr, length, prot, flags, fd, offset);
}
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