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gh-99726: Improves correctness of stat results for Windows, and uses faster API when available (GH-102149)

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This deprecates `st_ctime` fields on Windows, with the intent to change them to contain the correct value in 3.14. For now, they should keep returning the creation time as they always have.
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Steve Dower 2023-03-16 17:27:21 +00:00 • committed by GitHub
parent e108af6eca
commit 0f175766e2
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GPG key ID: 4AEE18F83AFDEB23
10 changed files with 446 additions and 82 deletions
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130
Python/fileutils.c
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@ -8,6 +8,8 @@
#ifdef MS_WINDOWS
# include <malloc.h>
# include <windows.h>
# include <winioctl.h> // FILE_DEVICE_* constants
# include "pycore_fileutils_windows.h" // FILE_STAT_BASIC_INFORMATION
# if defined(MS_WINDOWS_GAMES) && !defined(MS_WINDOWS_DESKTOP)
# define PATHCCH_ALLOW_LONG_PATHS 0x01
# else
@ -1056,6 +1058,13 @@ FILE_TIME_to_time_t_nsec(FILETIME *in_ptr, time_t *time_out, int* nsec_out)
*time_out = Py_SAFE_DOWNCAST((in / 10000000) - secs_between_epochs, __int64, time_t);
}
static void
LARGE_INTEGER_to_time_t_nsec(LARGE_INTEGER *in_ptr, time_t *time_out, int* nsec_out)
{
*nsec_out = (int)(in_ptr->QuadPart % 10000000) * 100; /* FILETIME is in units of 100 nsec. */
*time_out = Py_SAFE_DOWNCAST((in_ptr->QuadPart / 10000000) - secs_between_epochs, __int64, time_t);
}
void
_Py_time_t_to_FILE_TIME(time_t time_in, int nsec_in, FILETIME *out_ptr)
{
@ -1085,33 +1094,126 @@ attributes_to_mode(DWORD attr)
return m;
}
typedef union {
FILE_ID_128 id;
struct {
uint64_t st_ino;
uint64_t st_ino_high;
};
} id_128_to_ino;
void
_Py_attribute_data_to_stat(BY_HANDLE_FILE_INFORMATION *info, ULONG reparse_tag,
FILE_BASIC_INFO *basic_info, FILE_ID_INFO *id_info,
struct _Py_stat_struct *result)
{
memset(result, 0, sizeof(*result));
result->st_mode = attributes_to_mode(info->dwFileAttributes);
result->st_size = (((__int64)info->nFileSizeHigh)<<32) + info->nFileSizeLow;
result->st_dev = info->dwVolumeSerialNumber;
result->st_rdev = result->st_dev;
FILE_TIME_to_time_t_nsec(&info->ftCreationTime, &result->st_ctime, &result->st_ctime_nsec);
FILE_TIME_to_time_t_nsec(&info->ftLastWriteTime, &result->st_mtime, &result->st_mtime_nsec);
FILE_TIME_to_time_t_nsec(&info->ftLastAccessTime, &result->st_atime, &result->st_atime_nsec);
result->st_dev = id_info ? id_info->VolumeSerialNumber : info->dwVolumeSerialNumber;
result->st_rdev = 0;
/* st_ctime is deprecated, but we preserve the legacy value in our caller, not here */
if (basic_info) {
LARGE_INTEGER_to_time_t_nsec(&basic_info->CreationTime, &result->st_birthtime, &result->st_birthtime_nsec);
LARGE_INTEGER_to_time_t_nsec(&basic_info->ChangeTime, &result->st_ctime, &result->st_ctime_nsec);
LARGE_INTEGER_to_time_t_nsec(&basic_info->LastWriteTime, &result->st_mtime, &result->st_mtime_nsec);
LARGE_INTEGER_to_time_t_nsec(&basic_info->LastAccessTime, &result->st_atime, &result->st_atime_nsec);
} else {
FILE_TIME_to_time_t_nsec(&info->ftCreationTime, &result->st_birthtime, &result->st_birthtime_nsec);
FILE_TIME_to_time_t_nsec(&info->ftLastWriteTime, &result->st_mtime, &result->st_mtime_nsec);
FILE_TIME_to_time_t_nsec(&info->ftLastAccessTime, &result->st_atime, &result->st_atime_nsec);
}
result->st_nlink = info->nNumberOfLinks;
result->st_ino = (((uint64_t)info->nFileIndexHigh) << 32) + info->nFileIndexLow;
if (id_info) {
id_128_to_ino file_id;
file_id.id = id_info->FileId;
result->st_ino = file_id.st_ino;
result->st_ino_high = file_id.st_ino_high;
} else {
/* should only occur for DirEntry_from_find_data, in which case the
index is likely to be zero anyway. */
result->st_ino = (((uint64_t)info->nFileIndexHigh) << 32) + info->nFileIndexLow;
}
/* bpo-37834: Only actual symlinks set the S_IFLNK flag. But lstat() will
open other name surrogate reparse points without traversing them. To
detect/handle these, check st_file_attributes and st_reparse_tag. */
result->st_reparse_tag = reparse_tag;
if (info->dwFileAttributes & FILE_ATTRIBUTE_REPARSE_POINT &&
reparse_tag == IO_REPARSE_TAG_SYMLINK) {
/* first clear the S_IFMT bits */
result->st_mode ^= (result->st_mode & S_IFMT);
/* now set the bits that make this a symlink */
result->st_mode |= S_IFLNK;
/* set the bits that make this a symlink */
result->st_mode = (result->st_mode & ~S_IFMT) | S_IFLNK;
}
result->st_file_attributes = info->dwFileAttributes;
}
void
_Py_stat_basic_info_to_stat(FILE_STAT_BASIC_INFORMATION *info,
struct _Py_stat_struct *result)
{
memset(result, 0, sizeof(*result));
result->st_mode = attributes_to_mode(info->FileAttributes);
result->st_size = info->EndOfFile.QuadPart;
LARGE_INTEGER_to_time_t_nsec(&info->CreationTime, &result->st_birthtime, &result->st_birthtime_nsec);
LARGE_INTEGER_to_time_t_nsec(&info->ChangeTime, &result->st_ctime, &result->st_ctime_nsec);
LARGE_INTEGER_to_time_t_nsec(&info->LastWriteTime, &result->st_mtime, &result->st_mtime_nsec);
LARGE_INTEGER_to_time_t_nsec(&info->LastAccessTime, &result->st_atime, &result->st_atime_nsec);
result->st_nlink = info->NumberOfLinks;
result->st_dev = info->VolumeSerialNumber.QuadPart;
/* File systems with less than 128-bits zero pad into this field */
id_128_to_ino file_id;
file_id.id = info->FileId128;
result->st_ino = file_id.st_ino;
result->st_ino_high = file_id.st_ino_high;
/* bpo-37834: Only actual symlinks set the S_IFLNK flag. But lstat() will
open other name surrogate reparse points without traversing them. To
detect/handle these, check st_file_attributes and st_reparse_tag. */
result->st_reparse_tag = info->ReparseTag;
if (info->FileAttributes & FILE_ATTRIBUTE_REPARSE_POINT &&
info->ReparseTag == IO_REPARSE_TAG_SYMLINK) {
/* set the bits that make this a symlink */
result->st_mode = (result->st_mode & ~S_IFMT) | S_IFLNK;
}
result->st_file_attributes = info->FileAttributes;
switch (info->DeviceType) {
case FILE_DEVICE_DISK:
case FILE_DEVICE_VIRTUAL_DISK:
case FILE_DEVICE_DFS:
case FILE_DEVICE_CD_ROM:
case FILE_DEVICE_CONTROLLER:
case FILE_DEVICE_DATALINK:
break;
case FILE_DEVICE_DISK_FILE_SYSTEM:
case FILE_DEVICE_CD_ROM_FILE_SYSTEM:
case FILE_DEVICE_NETWORK_FILE_SYSTEM:
result->st_mode = (result->st_mode & ~S_IFMT) | 0x6000; /* _S_IFBLK */
break;
case FILE_DEVICE_CONSOLE:
case FILE_DEVICE_NULL:
case FILE_DEVICE_KEYBOARD:
case FILE_DEVICE_MODEM:
case FILE_DEVICE_MOUSE:
case FILE_DEVICE_PARALLEL_PORT:
case FILE_DEVICE_PRINTER:
case FILE_DEVICE_SCREEN:
case FILE_DEVICE_SERIAL_PORT:
case FILE_DEVICE_SOUND:
result->st_mode = (result->st_mode & ~S_IFMT) | _S_IFCHR;
break;
case FILE_DEVICE_NAMED_PIPE:
result->st_mode = (result->st_mode & ~S_IFMT) | _S_IFIFO;
break;
default:
if (info->FileAttributes & FILE_ATTRIBUTE_DIRECTORY) {
result->st_mode = (result->st_mode & ~S_IFMT) | _S_IFDIR;
}
break;
}
}
#endif
/* Return information about a file.
@ -1131,6 +1233,8 @@ _Py_fstat_noraise(int fd, struct _Py_stat_struct *status)
{
#ifdef MS_WINDOWS
BY_HANDLE_FILE_INFORMATION info;
FILE_BASIC_INFO basicInfo;
FILE_ID_INFO idInfo;
HANDLE h;
int type;
@ -1162,14 +1266,16 @@ _Py_fstat_noraise(int fd, struct _Py_stat_struct *status)
return 0;
}
if (!GetFileInformationByHandle(h, &info)) {
if (!GetFileInformationByHandle(h, &info) ||
!GetFileInformationByHandleEx(h, FileBasicInfo, &basicInfo, sizeof(basicInfo)) ||
!GetFileInformationByHandleEx(h, FileIdInfo, &idInfo, sizeof(idInfo))) {
/* The Win32 error is already set, but we also set errno for
callers who expect it */
errno = winerror_to_errno(GetLastError());
return -1;
}
_Py_attribute_data_to_stat(&info, 0, status);
_Py_attribute_data_to_stat(&info, 0, &basicInfo, &idInfo, status);
return 0;
#else
return fstat(fd, status);