//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// POSIX-like portability helper functions.
//
// These generally behave like the proper posix functions, with these
// exceptions:
// On Windows, they take paths in wchar_t* form, instead of char* form.
// The symlink() function is split into two frontends, symlink_file()
// and symlink_dir().
//
// These are provided within an anonymous namespace within the detail
// namespace - callers need to include this header and call them as
// detail::function(), regardless of platform.
//
#ifndef POSIX_COMPAT_H
#define POSIX_COMPAT_H
#include <__assert>
#include <__config>
#include <filesystem>
#include "error.h"
#include "time_utils.h"
#if defined(_LIBCPP_WIN32API)
# define WIN32_LEAN_AND_MEAN
# define NOMINMAX
# include <io.h>
# include <windows.h>
# include <winioctl.h>
#else
# include <fcntl.h>
# include <sys/stat.h>
# include <sys/statvfs.h>
# include <sys/time.h>
# include <unistd.h>
#endif
#include <stdlib.h>
#include <time.h>
#if defined(_LIBCPP_WIN32API)
// This struct isn't defined in the normal Windows SDK, but only in the
// Windows Driver Kit.
struct LIBCPP_REPARSE_DATA_BUFFER {
unsigned long ReparseTag;
unsigned short ReparseDataLength;
unsigned short Reserved;
union {
struct {
unsigned short SubstituteNameOffset;
unsigned short SubstituteNameLength;
unsigned short PrintNameOffset;
unsigned short PrintNameLength;
unsigned long Flags;
wchar_t PathBuffer[1];
} SymbolicLinkReparseBuffer;
struct {
unsigned short SubstituteNameOffset;
unsigned short SubstituteNameLength;
unsigned short PrintNameOffset;
unsigned short PrintNameLength;
wchar_t PathBuffer[1];
} MountPointReparseBuffer;
struct {
unsigned char DataBuffer[1];
} GenericReparseBuffer;
};
};
#endif
_LIBCPP_BEGIN_NAMESPACE_FILESYSTEM
namespace detail {
#if defined(_LIBCPP_WIN32API)
// Various C runtime header sets provide more or less of these. As we
// provide our own implementation, undef all potential defines from the
// C runtime headers and provide a complete set of macros of our own.
# undef _S_IFMT
# undef _S_IFDIR
# undef _S_IFCHR
# undef _S_IFIFO
# undef _S_IFREG
# undef _S_IFBLK
# undef _S_IFLNK
# undef _S_IFSOCK
# define _S_IFMT 0xF000
# define _S_IFDIR 0x4000
# define _S_IFCHR 0x2000
# define _S_IFIFO 0x1000
# define _S_IFREG 0x8000
# define _S_IFBLK 0x6000
# define _S_IFLNK 0xA000
# define _S_IFSOCK 0xC000
# undef S_ISDIR
# undef S_ISFIFO
# undef S_ISCHR
# undef S_ISREG
# undef S_ISLNK
# undef S_ISBLK
# undef S_ISSOCK
# define S_ISDIR(m) (((m) & _S_IFMT) == _S_IFDIR)
# define S_ISCHR(m) (((m) & _S_IFMT) == _S_IFCHR)
# define S_ISFIFO(m) (((m) & _S_IFMT) == _S_IFIFO)
# define S_ISREG(m) (((m) & _S_IFMT) == _S_IFREG)
# define S_ISBLK(m) (((m) & _S_IFMT) == _S_IFBLK)
# define S_ISLNK(m) (((m) & _S_IFMT) == _S_IFLNK)
# define S_ISSOCK(m) (((m) & _S_IFMT) == _S_IFSOCK)
# define O_NONBLOCK 0
inline int set_errno(int e = GetLastError()) {
errno = static_cast<int>(__win_err_to_errc(e));
return -1;
}
class WinHandle {
public:
WinHandle(const wchar_t* p, DWORD access, DWORD flags) {
h = CreateFileW(
p,
access,
FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
nullptr,
OPEN_EXISTING,
FILE_FLAG_BACKUP_SEMANTICS | flags,
nullptr);
}
~WinHandle() {
if (h != INVALID_HANDLE_VALUE)
CloseHandle(h);
}
operator HANDLE() const { return h; }
operator bool() const { return h != INVALID_HANDLE_VALUE; }
private:
HANDLE h;
};
inline int stat_handle(HANDLE h, StatT* buf) {
FILE_BASIC_INFO basic;
if (!GetFileInformationByHandleEx(h, FileBasicInfo, &basic, sizeof(basic)))
return set_errno();
memset(buf, 0, sizeof(*buf));
buf->st_mtim = filetime_to_timespec(basic.LastWriteTime);
buf->st_atim = filetime_to_timespec(basic.LastAccessTime);
buf->st_mode = 0555; // Read-only
if (!(basic.FileAttributes & FILE_ATTRIBUTE_READONLY))
buf->st_mode |= 0222; // Write
if (basic.FileAttributes & FILE_ATTRIBUTE_DIRECTORY) {
buf->st_mode |= _S_IFDIR;
} else {
buf->st_mode |= _S_IFREG;
}
if (basic.FileAttributes & FILE_ATTRIBUTE_REPARSE_POINT) {
FILE_ATTRIBUTE_TAG_INFO tag;
if (!GetFileInformationByHandleEx(h, FileAttributeTagInfo, &tag, sizeof(tag)))
return set_errno();
if (tag.ReparseTag == IO_REPARSE_TAG_SYMLINK)
buf->st_mode = (buf->st_mode & ~_S_IFMT) | _S_IFLNK;
}
FILE_STANDARD_INFO standard;
if (!GetFileInformationByHandleEx(h, FileStandardInfo, &standard, sizeof(standard)))
return set_errno();
buf->st_nlink = standard.NumberOfLinks;
buf->st_size = standard.EndOfFile.QuadPart;
BY_HANDLE_FILE_INFORMATION info;
if (!GetFileInformationByHandle(h, &info))
return set_errno();
buf->st_dev = info.dwVolumeSerialNumber;
memcpy(&buf->st_ino.id[0], &info.nFileIndexHigh, 4);
memcpy(&buf->st_ino.id[4], &info.nFileIndexLow, 4);
return 0;
}
inline int stat_file(const wchar_t* path, StatT* buf, DWORD flags) {
WinHandle h(path, FILE_READ_ATTRIBUTES, flags);
if (!h)
return set_errno();
int ret = stat_handle(h, buf);
return ret;
}
inline int stat(const wchar_t* path, StatT* buf) { return stat_file(path, buf, 0); }
inline int lstat(const wchar_t* path, StatT* buf) { return stat_file(path, buf, FILE_FLAG_OPEN_REPARSE_POINT); }
inline int fstat(int fd, StatT* buf) {
HANDLE h = reinterpret_cast<HANDLE>(_get_osfhandle(fd));
return stat_handle(h, buf);
}
inline int mkdir(const wchar_t* path, int permissions) {
(void)permissions;
if (!CreateDirectoryW(path, nullptr))
return set_errno();
return 0;
}
inline int symlink_file_dir(const wchar_t* oldname, const wchar_t* newname, bool is_dir) {
path dest(oldname);
dest.make_preferred();
oldname = dest.c_str();
DWORD flags = is_dir ? SYMBOLIC_LINK_FLAG_DIRECTORY : 0;
if (CreateSymbolicLinkW(newname, oldname, flags | SYMBOLIC_LINK_FLAG_ALLOW_UNPRIVILEGED_CREATE))
return 0;
int e = GetLastError();
if (e != ERROR_INVALID_PARAMETER)
return set_errno(e);
if (CreateSymbolicLinkW(newname, oldname, flags))
return 0;
return set_errno();
}
inline int symlink_file(const wchar_t* oldname, const wchar_t* newname) {
return symlink_file_dir(oldname, newname, false);
}
inline int symlink_dir(const wchar_t* oldname, const wchar_t* newname) {
return symlink_file_dir(oldname, newname, true);
}
inline int link(const wchar_t* oldname, const wchar_t* newname) {
if (CreateHardLinkW(newname, oldname, nullptr))
return 0;
return set_errno();
}
inline int remove(const wchar_t* path) {
detail::WinHandle h(path, DELETE, FILE_FLAG_OPEN_REPARSE_POINT);
if (!h)
return set_errno();
FILE_DISPOSITION_INFO info;
info.DeleteFile = TRUE;
if (!SetFileInformationByHandle(h, FileDispositionInfo, &info, sizeof(info)))
return set_errno();
return 0;
}
inline int truncate_handle(HANDLE h, off_t length) {
LARGE_INTEGER size_param;
size_param.QuadPart = length;
if (!SetFilePointerEx(h, size_param, 0, FILE_BEGIN))
return set_errno();
if (!SetEndOfFile(h))
return set_errno();
return 0;
}
inline int ftruncate(int fd, off_t length) {
HANDLE h = reinterpret_cast<HANDLE>(_get_osfhandle(fd));
return truncate_handle(h, length);
}
inline int truncate(const wchar_t* path, off_t length) {
detail::WinHandle h(path, GENERIC_WRITE, 0);
if (!h)
return set_errno();
return truncate_handle(h, length);
}
inline int rename(const wchar_t* from, const wchar_t* to) {
if (!(MoveFileExW(from, to, MOVEFILE_COPY_ALLOWED | MOVEFILE_REPLACE_EXISTING | MOVEFILE_WRITE_THROUGH)))
return set_errno();
return 0;
}
inline int chdir(const wchar_t* path) {
if (!SetCurrentDirectoryW(path))
return set_errno();
return 0;
}
struct StatVFS {
uint64_t f_frsize;
uint64_t f_blocks;
uint64_t f_bfree;
uint64_t f_bavail;
};
inline int statvfs(const wchar_t* p, StatVFS* buf) {
path dir = p;
while (true) {
error_code local_ec;
const file_status st = status(dir, local_ec);
if (!exists(st) || is_directory(st))
break;
path parent = dir.parent_path();
if (parent == dir) {
errno = ENOENT;
return -1;
}
dir = parent;
}
ULARGE_INTEGER free_bytes_available_to_caller, total_number_of_bytes, total_number_of_free_bytes;
if (!GetDiskFreeSpaceExW(
dir.c_str(), &free_bytes_available_to_caller, &total_number_of_bytes, &total_number_of_free_bytes))
return set_errno();
buf->f_frsize = 1;
buf->f_blocks = total_number_of_bytes.QuadPart;
buf->f_bfree = total_number_of_free_bytes.QuadPart;
buf->f_bavail = free_bytes_available_to_caller.QuadPart;
return 0;
}
inline wchar_t* getcwd([[maybe_unused]] wchar_t* in_buf, [[maybe_unused]] size_t in_size) {
// Only expected to be used with us allocating the buffer.
_LIBCPP_ASSERT_INTERNAL(in_buf == nullptr, "Windows getcwd() assumes in_buf==nullptr");
_LIBCPP_ASSERT_INTERNAL(in_size == 0, "Windows getcwd() assumes in_size==0");
size_t buff_size = MAX_PATH + 10;
std::unique_ptr<wchar_t, decltype(&::free)> buff(static_cast<wchar_t*>(malloc(buff_size * sizeof(wchar_t))), &::free);
DWORD retval = GetCurrentDirectoryW(buff_size, buff.get());
if (retval > buff_size) {
buff_size = retval;
buff.reset(static_cast<wchar_t*>(malloc(buff_size * sizeof(wchar_t))));
retval = GetCurrentDirectoryW(buff_size, buff.get());
}
if (!retval) {
set_errno();
return nullptr;
}
return buff.release();
}
inline wchar_t* realpath(const wchar_t* path, [[maybe_unused]] wchar_t* resolved_name) {
// Only expected to be used with us allocating the buffer.
_LIBCPP_ASSERT_INTERNAL(resolved_name == nullptr, "Windows realpath() assumes a null resolved_name");
WinHandle h(path, FILE_READ_ATTRIBUTES, 0);
if (!h) {
set_errno();
return nullptr;
}
size_t buff_size = MAX_PATH + 10;
std::unique_ptr<wchar_t, decltype(&::free)> buff(static_cast<wchar_t*>(malloc(buff_size * sizeof(wchar_t))), &::free);
DWORD retval = GetFinalPathNameByHandleW(h, buff.get(), buff_size, FILE_NAME_NORMALIZED | VOLUME_NAME_DOS);
if (retval > buff_size) {
buff_size = retval;
buff.reset(static_cast<wchar_t*>(malloc(buff_size * sizeof(wchar_t))));
retval = GetFinalPathNameByHandleW(h, buff.get(), buff_size, FILE_NAME_NORMALIZED | VOLUME_NAME_DOS);
}
if (!retval) {
set_errno();
return nullptr;
}
wchar_t* ptr = buff.get();
if (!wcsncmp(ptr, L"\\\\?\\", 4)) {
if (ptr[5] == ':') { // \\?\X: -> X:
memmove(&ptr[0], &ptr[4], (wcslen(&ptr[4]) + 1) * sizeof(wchar_t));
} else if (!wcsncmp(&ptr[4], L"UNC\\", 4)) { // \\?\UNC\server -> \\server
wcscpy(&ptr[0], L"\\\\");
memmove(&ptr[2], &ptr[8], (wcslen(&ptr[8]) + 1) * sizeof(wchar_t));
}
}
return buff.release();
}
# define AT_FDCWD -1
# define AT_SYMLINK_NOFOLLOW 1
using ModeT = int;
inline int fchmod_handle(HANDLE h, int perms) {
FILE_BASIC_INFO basic;
if (!GetFileInformationByHandleEx(h, FileBasicInfo, &basic, sizeof(basic)))
return set_errno();
DWORD orig_attributes = basic.FileAttributes;
basic.FileAttributes &= ~FILE_ATTRIBUTE_READONLY;
if ((perms & 0222) == 0)
basic.FileAttributes |= FILE_ATTRIBUTE_READONLY;
if (basic.FileAttributes != orig_attributes && !SetFileInformationByHandle(h, FileBasicInfo, &basic, sizeof(basic)))
return set_errno();
return 0;
}
inline int fchmodat(int /*fd*/, const wchar_t* path, int perms, int flag) {
DWORD attributes = GetFileAttributesW(path);
if (attributes == INVALID_FILE_ATTRIBUTES)
return set_errno();
if (attributes & FILE_ATTRIBUTE_REPARSE_POINT && !(flag & AT_SYMLINK_NOFOLLOW)) {
// If the file is a symlink, and we are supposed to operate on the target
// of the symlink, we need to open a handle to it, without the
// FILE_FLAG_OPEN_REPARSE_POINT flag, to open the destination of the
// symlink, and operate on it via the handle.
detail::WinHandle h(path, FILE_READ_ATTRIBUTES | FILE_WRITE_ATTRIBUTES, 0);
if (!h)
return set_errno();
return fchmod_handle(h, perms);
} else {
// For a non-symlink, or if operating on the symlink itself instead of
// its target, we can use SetFileAttributesW, saving a few calls.
DWORD orig_attributes = attributes;
attributes &= ~FILE_ATTRIBUTE_READONLY;
if ((perms & 0222) == 0)
attributes |= FILE_ATTRIBUTE_READONLY;
if (attributes != orig_attributes && !SetFileAttributesW(path, attributes))
return set_errno();
}
return 0;
}
inline int fchmod(int fd, int perms) {
HANDLE h = reinterpret_cast<HANDLE>(_get_osfhandle(fd));
return fchmod_handle(h, perms);
}
# define MAX_SYMLINK_SIZE MAXIMUM_REPARSE_DATA_BUFFER_SIZE
using SSizeT = ::int64_t;
inline SSizeT readlink(const wchar_t* path, wchar_t* ret_buf, size_t bufsize) {
uint8_t buf[MAXIMUM_REPARSE_DATA_BUFFER_SIZE];
detail::WinHandle h(path, FILE_READ_ATTRIBUTES, FILE_FLAG_OPEN_REPARSE_POINT);
if (!h)
return set_errno();
DWORD out;
if (!DeviceIoControl(h, FSCTL_GET_REPARSE_POINT, nullptr, 0, buf, sizeof(buf), &out, 0))
return set_errno();
const auto* reparse = reinterpret_cast<LIBCPP_REPARSE_DATA_BUFFER*>(buf);
size_t path_buf_offset = offsetof(LIBCPP_REPARSE_DATA_BUFFER, SymbolicLinkReparseBuffer.PathBuffer[0]);
if (out < path_buf_offset) {
errno = EINVAL;
return -1;
}
if (reparse->ReparseTag != IO_REPARSE_TAG_SYMLINK) {
errno = EINVAL;
return -1;
}
const auto& symlink = reparse->SymbolicLinkReparseBuffer;
unsigned short name_offset, name_length;
if (symlink.PrintNameLength == 0) {
name_offset = symlink.SubstituteNameOffset;
name_length = symlink.SubstituteNameLength;
} else {
name_offset = symlink.PrintNameOffset;
name_length = symlink.PrintNameLength;
}
// name_offset/length are expressed in bytes, not in wchar_t
if (path_buf_offset + name_offset + name_length > out) {
errno = EINVAL;
return -1;
}
if (name_length / sizeof(wchar_t) > bufsize) {
errno = ENOMEM;
return -1;
}
memcpy(ret_buf, &symlink.PathBuffer[name_offset / sizeof(wchar_t)], name_length);
return name_length / sizeof(wchar_t);
}
#else
inline int symlink_file(const char* oldname, const char* newname) { return ::symlink(oldname, newname); }
inline int symlink_dir(const char* oldname, const char* newname) { return ::symlink(oldname, newname); }
using ::chdir;
using ::fchmod;
# if defined(AT_SYMLINK_NOFOLLOW) && defined(AT_FDCWD)
using ::fchmodat;
# endif
using ::fstat;
using ::ftruncate;
using ::getcwd;
using ::link;
using ::lstat;
using ::mkdir;
using ::readlink;
using ::realpath;
using ::remove;
using ::rename;
using ::stat;
using ::statvfs;
using ::truncate;
# define O_BINARY 0
using StatVFS = struct statvfs;
using ModeT = ::mode_t;
using SSizeT = ::ssize_t;
#endif
} // namespace detail
_LIBCPP_END_NAMESPACE_FILESYSTEM
#endif // POSIX_COMPAT_H
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