reactos/sdk/lib/ucrt/filesystem/stat.cpp
2025-01-16 14:18:53 +02:00

606 lines
16 KiB
C++

/***
*stat64.c - get file status
*
* Copyright (c) Microsoft Corporation. All rights reserved.
*
*Purpose:
* defines _stat64() - get file status
*
*******************************************************************************/
#include <ctype.h>
#include <direct.h>
#include <errno.h>
#include <fcntl.h>
#include <corecrt_internal_lowio.h>
#include <corecrt_internal_time.h>
#include <corecrt_internal_win32_buffer.h>
#include <io.h>
#include <share.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/types.h>
namespace
{
struct file_handle_traits
{
typedef int type;
inline static bool close(_In_ type const fh) throw()
{
_close(fh);
return true;
}
inline static type get_invalid_value() throw()
{
return -1;
}
};
struct find_handle_traits
{
typedef HANDLE type;
static bool close(_In_ type const handle) throw()
{
return ::FindClose(handle) != FALSE;
}
static type get_invalid_value() throw()
{
return INVALID_HANDLE_VALUE;
}
};
typedef __crt_unique_handle_t<file_handle_traits> scoped_file_handle;
typedef __crt_unique_handle_t<find_handle_traits> unique_find_handle;
}
static bool __cdecl is_slash(wchar_t const c) throw()
{
return c == L'\\' || c == L'/';
}
static bool __cdecl compute_size(BY_HANDLE_FILE_INFORMATION const& file_info, long& size) throw()
{
size = 0;
_VALIDATE_RETURN_NOEXC(file_info.nFileSizeHigh == 0 && file_info.nFileSizeLow <= LONG_MAX, EOVERFLOW, false);
size = static_cast<long>(file_info.nFileSizeLow);
return true;
}
static bool __cdecl compute_size(BY_HANDLE_FILE_INFORMATION const& file_info, __int64& size) throw()
{
size = 0;
_VALIDATE_RETURN_NOEXC(file_info.nFileSizeHigh <= LONG_MAX, EOVERFLOW, false);
size = static_cast<__int64>(
static_cast<unsigned __int64>(file_info.nFileSizeHigh) * 0x100000000ll +
static_cast<unsigned __int64>(file_info.nFileSizeLow));
return true;
}
_Success_(return != 0)
static wchar_t* __cdecl call_wfullpath(
_Out_writes_z_(buffer_size) wchar_t* const buffer,
wchar_t const* const path,
size_t const buffer_size,
_Inout_ wchar_t** const buffer_result
) throw()
{
errno_t const saved_errno = errno;
errno = 0;
wchar_t* const result = _wfullpath(buffer, path, buffer_size);
if (result != nullptr)
{
errno = saved_errno;
return result;
}
if (errno != ERANGE)
return nullptr;
errno = saved_errno;
*buffer_result = _wfullpath(nullptr, path, 0);
return *buffer_result;
}
static bool __cdecl has_executable_extension(wchar_t const* const path) throw()
{
if (!path)
{
return false;
}
wchar_t const* const last_dot = wcsrchr(path, L'.');
if (!last_dot)
{
return false;
}
if (_wcsicmp(last_dot, L".exe") != 0 &&
_wcsicmp(last_dot, L".cmd") != 0 &&
_wcsicmp(last_dot, L".bat") != 0 &&
_wcsicmp(last_dot, L".com") != 0)
{
return false;
}
return true;
}
static bool __cdecl is_root_or_empty(wchar_t const* const path) throw()
{
if (!path)
{
return false;
}
bool const has_drive_letter_and_colon = __ascii_iswalpha(path[0]) && path[1] == L':';
wchar_t const* const path_start = has_drive_letter_and_colon
? path + 2
: path;
if (path_start[0] == L'\0')
{
return true;
}
if (is_slash(path_start[0]) && path_start[1] == L'\0')
{
return true;
}
return false;
}
static unsigned short __cdecl convert_to_stat_mode(
int const attributes,
wchar_t const* const path
) throw()
{
unsigned const os_mode = attributes & 0xff;
// check to see if this is a directory - note we must make a special
// check for the root, which DOS thinks is not a directory:
bool const is_directory = (os_mode & FILE_ATTRIBUTE_DIRECTORY) != 0;
unsigned short stat_mode = is_directory || is_root_or_empty(path)
? _S_IFDIR | _S_IEXEC
: _S_IFREG;
// If attribute byte does not have read-only bit, it is read-write:
stat_mode |= (os_mode & FILE_ATTRIBUTE_READONLY) != 0
? _S_IREAD
: _S_IREAD | _S_IWRITE;
// See if file appears to be an executable by checking its extension:
if (has_executable_extension(path))
stat_mode |= _S_IEXEC;
// propagate user read/write/execute bits to group/other fields:
stat_mode |= (stat_mode & 0700) >> 3;
stat_mode |= (stat_mode & 0700) >> 6;
return stat_mode;
}
// Returns false if and only if the path is invalid.
static bool __cdecl get_drive_number_from_path(wchar_t const* const path, int& drive_number) throw()
{
drive_number = 0;
// If path has a drive letter and a colon, return the value of that drive,
// as expected from _getdrive(). A = 1, B = 2, etc.
// If the path is relative, then use _getdrive() to get the current drive.
if (__ascii_iswalpha(path[0]) && path[1] == L':')
{
// If the path is just a drive letter followed by a colon, it is not a
// valid input to the stat functions:
if (path[2] == L'\0')
{
__acrt_errno_map_os_error(ERROR_FILE_NOT_FOUND);
return false;
}
drive_number = __ascii_towlower(path[0]) - L'a' + 1;
}
else
{
drive_number = _getdrive();
}
return true;
}
static bool __cdecl is_root_unc_name(wchar_t const* const path) throw()
{
// The shortest allowed string is of the form //x/y:
if (wcslen(path) < 5)
return 0;
// The string must begin with exactly two consecutive slashes:
if (!is_slash(path[0]) || !is_slash(path[1]) || is_slash(path[2]))
return 0;
// Find the slash between the server name and share name:
wchar_t const* p = path + 2; // Account for the two slashes
while (*++p)
{
if (is_slash(*p))
break;
}
// We reached the end before finding a slash, or the slash is at the end:
if (p[0] == L'\0' || p[1] == L'\0')
return 0;
// Is there a further slash?
while (*++p)
{
if (is_slash(*p))
break;
}
// Just the final slash (or no final slash):
if (p[0] == L'\0' || p[1] == L'\0')
return 1;
return 0;
}
static bool __cdecl is_usable_drive_or_unc_root(wchar_t const* const path) throw()
{
if (wcspbrk(path, L"./\\") == nullptr)
return false;
wchar_t full_path_buffer[_MAX_PATH];
__crt_unique_heap_ptr<wchar_t, __crt_public_free_policy> full_path_pointer;
wchar_t* const full_path = call_wfullpath(
full_path_buffer,
path,
_MAX_PATH,
full_path_pointer.get_address_of());
if (full_path == nullptr)
return false;
// Check to see if the path is a root of a directory ("C:\") or a UNC root
// directory ("\\server\share\"):
if (wcslen(full_path) != 3 && !is_root_unc_name(full_path))
return false;
if (GetDriveTypeW(path) <= 1)
return false;
return true;
}
template <typename TimeType>
static TimeType __cdecl convert_filetime_to_time_t(
FILETIME const file_time,
TimeType const fallback_time
) throw()
{
using time_traits = __crt_time_time_t_traits<TimeType>;
if (file_time.dwLowDateTime == 0 && file_time.dwHighDateTime == 0)
{
return fallback_time;
}
SYSTEMTIME system_time;
SYSTEMTIME local_time;
if (!FileTimeToSystemTime(&file_time, &system_time) ||
!SystemTimeToTzSpecificLocalTime(nullptr, &system_time, &local_time))
{
// Ignore failures from these APIs, for consistency with the logic below
// that ignores failures in the conversion from SYSTEMTIME to time_t.
return -1;
}
// If the conversion to time_t fails, it will return -1. We'll use this as
// the time_t value instead of failing the entire stat call, to allow callers
// to get information about files whose time information is not representable.
// (Callers use this API to test for file existence or to get file sizes.)
return time_traits::loctotime(
local_time.wYear,
local_time.wMonth,
local_time.wDay,
local_time.wHour,
local_time.wMinute,
local_time.wSecond,
-1);
}
template <typename StatStruct>
static bool __cdecl common_stat_handle_file_not_opened(
wchar_t const* const path,
StatStruct& result
) throw()
{
using time_traits = __crt_time_time_t_traits<decltype(result.st_mtime)>;
if (!is_usable_drive_or_unc_root(path))
{
__acrt_errno_map_os_error(ERROR_FILE_NOT_FOUND);
return false;
}
// Root directories (such as C:\ or \\server\share\) are fabricated:
result.st_mode = convert_to_stat_mode(FILE_ATTRIBUTE_DIRECTORY, path);
result.st_nlink = 1;
// Try to get the disk from the name; if there is none, get the current disk:
int drive_number{};
if (!get_drive_number_from_path(path, drive_number))
{
return false;
}
result.st_rdev = static_cast<_dev_t>(drive_number - 1);
result.st_dev = static_cast<_dev_t>(drive_number - 1); // A=0, B=1, etc.
result.st_mtime = time_traits::loctotime(1980, 1, 1, 0, 0, 0, -1);
result.st_atime = result.st_mtime;
result.st_ctime = result.st_mtime;
return true;
}
template <typename StatStruct>
static bool __cdecl common_stat_handle_file_opened(
wchar_t const* const path,
int const fh,
HANDLE const handle,
StatStruct& result
) throw()
{
using time_type = decltype(result.st_mtime);
// Figure out what kind of file underlies the file handle:
int const file_type = GetFileType(handle) & ~FILE_TYPE_REMOTE;
if (file_type == FILE_TYPE_DISK)
{
// Okay, it's a disk file; we'll do the normal logic below.
}
else if (file_type == FILE_TYPE_CHAR || file_type == FILE_TYPE_PIPE)
{
// We treat pipes and devices similarly: no further information is
// available from any API, so we set the fields as reasonably as
// possible and return.
result.st_mode = file_type == FILE_TYPE_CHAR
? _S_IFCHR
: _S_IFIFO;
result.st_nlink = 1;
result.st_rdev = static_cast<unsigned>(fh);
result.st_dev = static_cast<unsigned>(fh);
if (file_type != FILE_TYPE_CHAR)
{
unsigned long available;
if (PeekNamedPipe(handle, nullptr, 0, nullptr, &available, nullptr))
{
result.st_size = static_cast<_off_t>(available);
}
}
return true;
}
else if (file_type == FILE_TYPE_UNKNOWN)
{
errno = EBADF;
return false;
}
else
{
// Per the documentation we should not reach here, but we'll add
// this just to be safe:
__acrt_errno_map_os_error(GetLastError());
return false;
}
// At this point, we know we have a file on disk. Set the common fields:
result.st_nlink = 1;
if (path)
{
// Try to get the disk from the name; if there is none, get the current disk:
int drive_number{};
if (!get_drive_number_from_path(path, drive_number))
{
return false;
}
result.st_rdev = static_cast<_dev_t>(drive_number - 1);
result.st_dev = static_cast<_dev_t>(drive_number - 1); // A=0, B=1, etc.
}
BY_HANDLE_FILE_INFORMATION file_info{};
if (!GetFileInformationByHandle(handle, &file_info))
{
__acrt_errno_map_os_error(GetLastError());
return false;
}
result.st_mode = convert_to_stat_mode(file_info.dwFileAttributes, path);
result.st_mtime = convert_filetime_to_time_t(file_info.ftLastWriteTime, static_cast<time_type>(0));
result.st_atime = convert_filetime_to_time_t(file_info.ftLastAccessTime, result.st_mtime);
result.st_ctime = convert_filetime_to_time_t(file_info.ftCreationTime, result.st_mtime);
if (!compute_size(file_info, result.st_size))
{
return false;
}
return true;
}
template <typename StatStruct>
static int __cdecl common_stat(
wchar_t const* const path,
StatStruct* const result
) throw()
{
_VALIDATE_CLEAR_OSSERR_RETURN(result != nullptr, EINVAL, -1);
*result = StatStruct{};
_VALIDATE_CLEAR_OSSERR_RETURN(path != nullptr, EINVAL, -1);
__crt_unique_handle const file_handle(CreateFileW(
path,
FILE_READ_ATTRIBUTES,
FILE_SHARE_DELETE | FILE_SHARE_READ | FILE_SHARE_WRITE,
nullptr,
OPEN_EXISTING,
FILE_FLAG_BACKUP_SEMANTICS,
nullptr));
if (file_handle)
{
if (!common_stat_handle_file_opened(path, -1, file_handle.get(), *result))
{
*result = StatStruct{};
return -1;
}
}
else
{
if (!common_stat_handle_file_not_opened(path, *result))
{
*result = StatStruct{};
return -1;
}
}
return 0;
}
template <typename StatStruct>
static int __cdecl common_stat(
char const* const path,
StatStruct* const result
) throw()
{
if (path == nullptr) {
return common_stat(static_cast<wchar_t const*>(nullptr), result);
}
__crt_internal_win32_buffer<wchar_t> wide_path;
errno_t const cvt = __acrt_mbs_to_wcs_cp(path, wide_path, __acrt_get_utf8_acp_compatibility_codepage());
if (cvt != 0) {
return -1;
}
return common_stat(wide_path.data(), result);
}
extern "C" int __cdecl _stat32(char const* const path, struct _stat32* const result)
{
return common_stat(path, result);
}
extern "C" int __cdecl _stat32i64(char const* const path, struct _stat32i64* const result)
{
return common_stat(path, result);
}
extern "C" int __cdecl _stat64(char const* const path, struct _stat64* const result)
{
return common_stat(path, result);
}
extern "C" int __cdecl _stat64i32(char const* const path, struct _stat64i32* const result)
{
return common_stat(path, result);
}
extern "C" int __cdecl _wstat32(wchar_t const* const path, struct _stat32* const result)
{
return common_stat(path, result);
}
extern "C" int __cdecl _wstat32i64(wchar_t const* const path, struct _stat32i64* const result)
{
return common_stat(path, result);
}
extern "C" int __cdecl _wstat64(wchar_t const* const path, struct _stat64* const result)
{
return common_stat(path, result);
}
extern "C" int __cdecl _wstat64i32(wchar_t const* const path, struct _stat64i32* const result)
{
return common_stat(path, result);
}
template <typename StatStruct>
static int __cdecl common_fstat(int const fh, StatStruct* const result) throw()
{
_VALIDATE_CLEAR_OSSERR_RETURN(result != nullptr, EINVAL, -1);
*result = StatStruct{};
_CHECK_FH_CLEAR_OSSERR_RETURN(fh, EBADF, -1);
_VALIDATE_CLEAR_OSSERR_RETURN(fh >= 0 && fh < _nhandle, EBADF, -1);
_VALIDATE_CLEAR_OSSERR_RETURN(_osfile(fh) & FOPEN, EBADF, -1);
return __acrt_lowio_lock_fh_and_call(fh, [&]()
{
if ((_osfile(fh) & FOPEN) == 0)
{
errno = EBADF;
_ASSERTE(("Invalid file descriptor. File possibly closed by a different thread",0));
return -1;
}
if (!common_stat_handle_file_opened(nullptr, fh, reinterpret_cast<HANDLE>(_osfhnd(fh)), *result))
{
*result = StatStruct{};
return -1;
}
return 0;
});
}
extern "C" int __cdecl _fstat32(int const fh, struct _stat32* const result)
{
return common_fstat(fh, result);
}
extern "C" int __cdecl _fstat32i64(int const fh, struct _stat32i64* const result)
{
return common_fstat(fh, result);
}
extern "C" int __cdecl _fstat64(int const fh, struct _stat64* const result)
{
return common_fstat(fh, result);
}
extern "C" int __cdecl _fstat64i32(int const fh, struct _stat64i32* const result)
{
return common_fstat(fh, result);
}