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#include <Common/atomicRename.h>
#include <Common/Exception.h>
#include <Common/VersionNumber.h>
#include <Poco/Environment.h>
#include <filesystem>
namespace fs = std::filesystem;
namespace DB
{
namespace ErrorCodes
{
extern const int LOGICAL_ERROR;
extern const int ATOMIC_RENAME_FAIL;
extern const int SYSTEM_ERROR;
extern const int UNSUPPORTED_METHOD;
extern const int FILE_ALREADY_EXISTS;
}
}
#if defined(OS_LINUX)
#include <unistd.h>
#include <fcntl.h>
#include <sys/syscall.h>
#include <linux/fs.h>
/// For old versions of libc.
#if !defined(RENAME_NOREPLACE)
#define RENAME_NOREPLACE 1
#endif
#if !defined(RENAME_EXCHANGE)
#define RENAME_EXCHANGE 2
#endif
#if !defined(__NR_renameat2)
#if defined(__x86_64__)
#define __NR_renameat2 316
#elif defined(__aarch64__)
#define __NR_renameat2 276
#elif defined(__powerpc64__)
#define __NR_renameat2 357
#elif defined(__riscv)
#define __NR_renameat2 276
#else
#error "Unsupported architecture"
#endif
#endif
namespace DB
{
static bool supportsAtomicRenameImpl()
{
VersionNumber renameat2_minimal_version(3, 15, 0);
VersionNumber linux_version(Poco::Environment::osVersion());
return linux_version >= renameat2_minimal_version;
}
static bool renameat2(const std::string & old_path, const std::string & new_path, int flags)
{
if (!supportsAtomicRename())
return false;
if (old_path.empty() || new_path.empty())
throw Exception(ErrorCodes::LOGICAL_ERROR, "Cannot rename {} to {}: path is empty", old_path, new_path);
/// int olddirfd (ignored for absolute oldpath), const char *oldpath,
/// int newdirfd (ignored for absolute newpath), const char *newpath,
/// unsigned int flags
if (0 == syscall(__NR_renameat2, AT_FDCWD, old_path.c_str(), AT_FDCWD, new_path.c_str(), flags))
return true;
/// EINVAL means that filesystem does not support one of the flags.
/// It also may happen when running clickhouse in docker with Mac OS as a host OS.
/// supportsRenameat2() with uname is not enough in this case, because virtualized Linux kernel is used.
/// Other cases when EINVAL can be returned should never happen.
if (errno == EINVAL)
return false;
/// We should never get ENOSYS on Linux, because we check kernel version in supportsRenameat2Impl().
/// However, we can get in on WSL.
if (errno == ENOSYS)
return false;
if (errno == EEXIST)
throwFromErrno(fmt::format("Cannot rename {} to {} because the second path already exists", old_path, new_path), ErrorCodes::ATOMIC_RENAME_FAIL);
if (errno == ENOENT)
throwFromErrno(fmt::format("Paths cannot be exchanged because {} or {} does not exist", old_path, new_path), ErrorCodes::ATOMIC_RENAME_FAIL);
throwFromErrnoWithPath(fmt::format("Cannot rename {} to {}", old_path, new_path), new_path, ErrorCodes::SYSTEM_ERROR);
}
bool supportsAtomicRename()
{
static bool supports = supportsAtomicRenameImpl();
return supports;
}
}
#elif defined(OS_DARWIN)
// Includes
#include <dlfcn.h> // For dlsym
#include <stdio.h> // For renamex_np
#include <string.h> // For stderror
#ifndef RENAME_SWAP
#define RENAME_SWAP 0x00000002
#endif
#ifndef RENAME_EXCL
#define RENAME_EXCL 0x00000004
#endif
#define RENAME_NOREPLACE RENAME_EXCL
#define RENAME_EXCHANGE RENAME_SWAP
namespace DB
{
static bool renameat2(const std::string & old_path, const std::string & new_path, int flags)
{
using function_type = int (*)(const char * from, const char * to, unsigned int flags);
static function_type fun = reinterpret_cast<function_type>(dlsym(RTLD_DEFAULT, "renamex_np"));
if (fun == nullptr)
return false;
if (old_path.empty() || new_path.empty())
throw Exception(ErrorCodes::LOGICAL_ERROR, "Cannot rename {} to {}: path is empty", old_path, new_path);
if (0 == (*fun)(old_path.c_str(), new_path.c_str(), flags))
return true;
int errnum = errno;
if (errnum == ENOTSUP || errnum == EINVAL)
return false;
if (errnum == EEXIST)
throwFromErrno(fmt::format("Cannot rename {} to {} because the second path already exists", old_path, new_path), ErrorCodes::ATOMIC_RENAME_FAIL);
if (errnum == ENOENT)
throwFromErrno(fmt::format("Paths cannot be exchanged because {} or {} does not exist", old_path, new_path), ErrorCodes::ATOMIC_RENAME_FAIL);
throwFromErrnoWithPath(
fmt::format("Cannot rename {} to {}: {}", old_path, new_path, strerror(errnum)), new_path, ErrorCodes::SYSTEM_ERROR);
}
static bool supportsAtomicRenameImpl()
{
auto fun = dlsym(RTLD_DEFAULT, "renamex_np");
return fun != nullptr;
}
bool supportsAtomicRename()
{
static bool supports = supportsAtomicRenameImpl();
return supports;
}
}
#else
#define RENAME_NOREPLACE -1
#define RENAME_EXCHANGE -1
namespace DB
{
static bool renameat2(const std::string &, const std::string &, int)
{
return false;
}
bool supportsAtomicRename()
{
return false;
}
}
#endif
namespace DB
{
static void renameNoReplaceFallback(const std::string & old_path, const std::string & new_path)
{
/// NOTE it's unsafe
if (fs::exists(new_path))
throw Exception(ErrorCodes::FILE_ALREADY_EXISTS, "File {} exists", new_path);
fs::rename(old_path, new_path);
}
/// Do not use [[noreturn]] to avoid warnings like "code will never be executed" in other places
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wmissing-noreturn"
static void renameExchangeFallback(const std::string &, const std::string &)
{
throw Exception(ErrorCodes::UNSUPPORTED_METHOD, "System call renameat2() is not supported");
}
#pragma clang diagnostic pop
void renameNoReplace(const std::string & old_path, const std::string & new_path)
{
if (!renameat2(old_path, new_path, RENAME_NOREPLACE))
renameNoReplaceFallback(old_path, new_path);
}
void renameExchange(const std::string & old_path, const std::string & new_path)
{
if (!renameat2(old_path, new_path, RENAME_EXCHANGE))
renameExchangeFallback(old_path, new_path);
}
bool renameExchangeIfSupported(const std::string & old_path, const std::string & new_path)
{
return renameat2(old_path, new_path, RENAME_EXCHANGE);
}
}
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