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cpython/Python/fileutils.c

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#include "Python.h"
#include "osdefs.h"
#include <locale.h>
#ifdef MS_WINDOWS
# include <malloc.h>
# include <windows.h>
extern int winerror_to_errno(int);
#endif
#ifdef HAVE_LANGINFO_H
#include <langinfo.h>
#endif
#ifdef HAVE_SYS_IOCTL_H
#include <sys/ioctl.h>
#endif
#ifdef HAVE_FCNTL_H
#include <fcntl.h>
#endif /* HAVE_FCNTL_H */
#if defined(__APPLE__) || defined(__ANDROID__)
extern wchar_t* _Py_DecodeUTF8_surrogateescape(const char *s, Py_ssize_t size);
#endif
#ifdef O_CLOEXEC
/* Does open() support the O_CLOEXEC flag? Possible values:
-1: unknown
0: open() ignores O_CLOEXEC flag, ex: Linux kernel older than 2.6.23
1: open() supports O_CLOEXEC flag, close-on-exec is set
The flag is used by _Py_open(), _Py_open_noraise(), io.FileIO
and os.open(). */
int _Py_open_cloexec_works = -1;
#endif
PyObject *
_Py_device_encoding(int fd)
{
#if defined(MS_WINDOWS)
UINT cp;
#endif
int valid;
_Py_BEGIN_SUPPRESS_IPH
valid = isatty(fd);
_Py_END_SUPPRESS_IPH
if (!valid)
Py_RETURN_NONE;
#if defined(MS_WINDOWS)
if (fd == 0)
cp = GetConsoleCP();
else if (fd == 1 || fd == 2)
cp = GetConsoleOutputCP();
else
cp = 0;
/* GetConsoleCP() and GetConsoleOutputCP() return 0 if the application
has no console */
if (cp != 0)
return PyUnicode_FromFormat("cp%u", (unsigned int)cp);
#elif defined(CODESET)
{
char *codeset = nl_langinfo(CODESET);
if (codeset != NULL && codeset[0] != 0)
return PyUnicode_FromString(codeset);
}
#endif
Py_RETURN_NONE;
}
#if !defined(__APPLE__) && !defined(MS_WINDOWS)
extern int _Py_normalize_encoding(const char *, char *, size_t);
/* Workaround FreeBSD and OpenIndiana locale encoding issue with the C locale.
On these operating systems, nl_langinfo(CODESET) announces an alias of the
ASCII encoding, whereas mbstowcs() and wcstombs() functions use the
ISO-8859-1 encoding. The problem is that os.fsencode() and os.fsdecode() use
locale.getpreferredencoding() codec. For example, if command line arguments
are decoded by mbstowcs() and encoded back by os.fsencode(), we get a
UnicodeEncodeError instead of retrieving the original byte string.
The workaround is enabled if setlocale(LC_CTYPE, NULL) returns "C",
nl_langinfo(CODESET) announces "ascii" (or an alias to ASCII), and at least
one byte in range 0x80-0xff can be decoded from the locale encoding. The
workaround is also enabled on error, for example if getting the locale
failed.
Values of force_ascii:
1: the workaround is used: Py_EncodeLocale() uses
encode_ascii_surrogateescape() and Py_DecodeLocale() uses
decode_ascii_surrogateescape()
0: the workaround is not used: Py_EncodeLocale() uses wcstombs() and
Py_DecodeLocale() uses mbstowcs()
-1: unknown, need to call check_force_ascii() to get the value
*/
static int force_ascii = -1;
static int
check_force_ascii(void)
{
char *loc;
#if defined(HAVE_LANGINFO_H) && defined(CODESET)
char *codeset, **alias;
char encoding[20]; /* longest name: "iso_646.irv_1991\0" */
int is_ascii;
unsigned int i;
char* ascii_aliases[] = {
"ascii",
/* Aliases from Lib/encodings/aliases.py */
"646",
"ansi_x3.4_1968",
"ansi_x3.4_1986",
"ansi_x3_4_1968",
"cp367",
"csascii",
"ibm367",
"iso646_us",
"iso_646.irv_1991",
"iso_ir_6",
"us",
"us_ascii",
NULL
};
#endif
loc = setlocale(LC_CTYPE, NULL);
if (loc == NULL)
goto error;
if (strcmp(loc, "C") != 0) {
/* the LC_CTYPE locale is different than C */
return 0;
}
#if defined(HAVE_LANGINFO_H) && defined(CODESET)
codeset = nl_langinfo(CODESET);
if (!codeset || codeset[0] == '\0') {
/* CODESET is not set or empty */
goto error;
}
if (!_Py_normalize_encoding(codeset, encoding, sizeof(encoding)))
goto error;
is_ascii = 0;
for (alias=ascii_aliases; *alias != NULL; alias++) {
if (strcmp(encoding, *alias) == 0) {
is_ascii = 1;
break;
}
}
if (!is_ascii) {
/* nl_langinfo(CODESET) is not "ascii" or an alias of ASCII */
return 0;
}
for (i=0x80; i<0xff; i++) {
unsigned char ch;
wchar_t wch;
size_t res;
ch = (unsigned char)i;
res = mbstowcs(&wch, (char*)&ch, 1);
if (res != (size_t)-1) {
/* decoding a non-ASCII character from the locale encoding succeed:
the locale encoding is not ASCII, force ASCII */
return 1;
}
}
/* None of the bytes in the range 0x80-0xff can be decoded from the locale
encoding: the locale encoding is really ASCII */
return 0;
#else
/* nl_langinfo(CODESET) is not available: always force ASCII */
return 1;
#endif
error:
/* if an error occurred, force the ASCII encoding */
return 1;
}
static char*
encode_ascii_surrogateescape(const wchar_t *text, size_t *error_pos)
{
char *result = NULL, *out;
size_t len, i;
wchar_t ch;
if (error_pos != NULL)
*error_pos = (size_t)-1;
len = wcslen(text);
result = PyMem_Malloc(len + 1); /* +1 for NUL byte */
if (result == NULL)
return NULL;
out = result;
for (i=0; i<len; i++) {
ch = text[i];
if (ch <= 0x7f) {
/* ASCII character */
*out++ = (char)ch;
}
else if (0xdc80 <= ch && ch <= 0xdcff) {
/* UTF-8b surrogate */
*out++ = (char)(ch - 0xdc00);
}
else {
if (error_pos != NULL)
*error_pos = i;
PyMem_Free(result);
return NULL;
}
}
*out = '\0';
return result;
}
#endif /* !defined(__APPLE__) && !defined(MS_WINDOWS) */
#if !defined(__APPLE__) && (!defined(MS_WINDOWS) || !defined(HAVE_MBRTOWC))
static wchar_t*
decode_ascii_surrogateescape(const char *arg, size_t *size)
{
wchar_t *res;
unsigned char *in;
wchar_t *out;
size_t argsize = strlen(arg) + 1;
if (argsize > PY_SSIZE_T_MAX/sizeof(wchar_t))
return NULL;
res = PyMem_RawMalloc(argsize*sizeof(wchar_t));
if (!res)
return NULL;
in = (unsigned char*)arg;
out = res;
while(*in)
if(*in < 128)
*out++ = *in++;
else
*out++ = 0xdc00 + *in++;
*out = 0;
if (size != NULL)
*size = out - res;
return res;
}
#endif
/* Decode a byte string from the locale encoding with the
surrogateescape error handler: undecodable bytes are decoded as characters
in range U+DC80..U+DCFF. If a byte sequence can be decoded as a surrogate
character, escape the bytes using the surrogateescape error handler instead
of decoding them.
Return a pointer to a newly allocated wide character string, use
PyMem_RawFree() to free the memory. If size is not NULL, write the number of
wide characters excluding the null character into *size
Return NULL on decoding error or memory allocation error. If *size* is not
NULL, *size is set to (size_t)-1 on memory error or set to (size_t)-2 on
decoding error.
Decoding errors should never happen, unless there is a bug in the C
library.
Use the Py_EncodeLocale() function to encode the character string back to a
byte string. */
wchar_t*
Py_DecodeLocale(const char* arg, size_t *size)
{
#if defined(__APPLE__) || defined(__ANDROID__)
wchar_t *wstr;
wstr = _Py_DecodeUTF8_surrogateescape(arg, strlen(arg));
if (size != NULL) {
if (wstr != NULL)
*size = wcslen(wstr);
else
*size = (size_t)-1;
}
return wstr;
#else
wchar_t *res;
size_t argsize;
size_t count;
#ifdef HAVE_MBRTOWC
unsigned char *in;
wchar_t *out;
mbstate_t mbs;
#endif
#ifndef MS_WINDOWS
if (force_ascii == -1)
force_ascii = check_force_ascii();
if (force_ascii) {
/* force ASCII encoding to workaround mbstowcs() issue */
res = decode_ascii_surrogateescape(arg, size);
if (res == NULL)
goto oom;
return res;
}
#endif
#ifdef HAVE_BROKEN_MBSTOWCS
/* Some platforms have a broken implementation of
* mbstowcs which does not count the characters that
* would result from conversion. Use an upper bound.
*/
argsize = strlen(arg);
#else
argsize = mbstowcs(NULL, arg, 0);
#endif
if (argsize != (size_t)-1) {
if (argsize == PY_SSIZE_T_MAX)
goto oom;
argsize += 1;
if (argsize > PY_SSIZE_T_MAX/sizeof(wchar_t))
goto oom;
res = (wchar_t *)PyMem_RawMalloc(argsize*sizeof(wchar_t));
if (!res)
goto oom;
count = mbstowcs(res, arg, argsize);
if (count != (size_t)-1) {
wchar_t *tmp;
/* Only use the result if it contains no
surrogate characters. */
for (tmp = res; *tmp != 0 &&
!Py_UNICODE_IS_SURROGATE(*tmp); tmp++)
;
if (*tmp == 0) {
if (size != NULL)
*size = count;
return res;
}
}
PyMem_RawFree(res);
}
/* Conversion failed. Fall back to escaping with surrogateescape. */
#ifdef HAVE_MBRTOWC
/* Try conversion with mbrtwoc (C99), and escape non-decodable bytes. */
/* Overallocate; as multi-byte characters are in the argument, the
actual output could use less memory. */
argsize = strlen(arg) + 1;
if (argsize > PY_SSIZE_T_MAX/sizeof(wchar_t))
goto oom;
res = (wchar_t*)PyMem_RawMalloc(argsize*sizeof(wchar_t));
if (!res)
goto oom;
in = (unsigned char*)arg;
out = res;
memset(&mbs, 0, sizeof mbs);
while (argsize) {
size_t converted = mbrtowc(out, (char*)in, argsize, &mbs);
if (converted == 0)
/* Reached end of string; null char stored. */
break;
if (converted == (size_t)-2) {
/* Incomplete character. This should never happen,
since we provide everything that we have -
unless there is a bug in the C library, or I
misunderstood how mbrtowc works. */
PyMem_RawFree(res);
if (size != NULL)
*size = (size_t)-2;
return NULL;
}
if (converted == (size_t)-1) {
/* Conversion error. Escape as UTF-8b, and start over
in the initial shift state. */
*out++ = 0xdc00 + *in++;
argsize--;
memset(&mbs, 0, sizeof mbs);
continue;
}
if (Py_UNICODE_IS_SURROGATE(*out)) {
/* Surrogate character. Escape the original
byte sequence with surrogateescape. */
argsize -= converted;
while (converted--)
*out++ = 0xdc00 + *in++;
continue;
}
/* successfully converted some bytes */
in += converted;
argsize -= converted;
out++;
}
if (size != NULL)
*size = out - res;
#else /* HAVE_MBRTOWC */
/* Cannot use C locale for escaping; manually escape as if charset
is ASCII (i.e. escape all bytes > 128. This will still roundtrip
correctly in the locale's charset, which must be an ASCII superset. */
res = decode_ascii_surrogateescape(arg, size);
if (res == NULL)
goto oom;
#endif /* HAVE_MBRTOWC */
return res;
oom:
if (size != NULL)
*size = (size_t)-1;
return NULL;
#endif /* __APPLE__ or __ANDROID__ */
}
/* Encode a wide character string to the locale encoding with the
surrogateescape error handler: surrogate characters in the range
U+DC80..U+DCFF are converted to bytes 0x80..0xFF.
Return a pointer to a newly allocated byte string, use PyMem_Free() to free
the memory. Return NULL on encoding or memory allocation error.
If error_pos is not NULL, *error_pos is set to the index of the invalid
character on encoding error, or set to (size_t)-1 otherwise.
Use the Py_DecodeLocale() function to decode the bytes string back to a wide
character string. */
char*
Py_EncodeLocale(const wchar_t *text, size_t *error_pos)
{
#if defined(__APPLE__) || defined(__ANDROID__)
Py_ssize_t len;
PyObject *unicode, *bytes = NULL;
char *cpath;
unicode = PyUnicode_FromWideChar(text, wcslen(text));
if (unicode == NULL)
return NULL;
bytes = _PyUnicode_AsUTF8String(unicode, "surrogateescape");
Py_DECREF(unicode);
if (bytes == NULL) {
PyErr_Clear();
if (error_pos != NULL)
*error_pos = (size_t)-1;
return NULL;
}
len = PyBytes_GET_SIZE(bytes);
cpath = PyMem_Malloc(len+1);
if (cpath == NULL) {
PyErr_Clear();
Py_DECREF(bytes);
if (error_pos != NULL)
*error_pos = (size_t)-1;
return NULL;
}
memcpy(cpath, PyBytes_AsString(bytes), len + 1);
Py_DECREF(bytes);
return cpath;
#else /* __APPLE__ */
const size_t len = wcslen(text);
char *result = NULL, *bytes = NULL;
size_t i, size, converted;
wchar_t c, buf[2];
#ifndef MS_WINDOWS
if (force_ascii == -1)
force_ascii = check_force_ascii();
if (force_ascii)
return encode_ascii_surrogateescape(text, error_pos);
#endif
/* The function works in two steps:
1. compute the length of the output buffer in bytes (size)
2. outputs the bytes */
size = 0;
buf[1] = 0;
while (1) {
for (i=0; i < len; i++) {
c = text[i];
if (c >= 0xdc80 && c <= 0xdcff) {
/* UTF-8b surrogate */
if (bytes != NULL) {
*bytes++ = c - 0xdc00;
size--;
}
else
size++;
continue;
}
else {
buf[0] = c;
if (bytes != NULL)
converted = wcstombs(bytes, buf, size);
else
converted = wcstombs(NULL, buf, 0);
if (converted == (size_t)-1) {
if (result != NULL)
PyMem_Free(result);
if (error_pos != NULL)
*error_pos = i;
return NULL;
}
if (bytes != NULL) {
bytes += converted;
size -= converted;
}
else
size += converted;
}
}
if (result != NULL) {
*bytes = '\0';
break;
}
size += 1; /* nul byte at the end */
result = PyMem_Malloc(size);
if (result == NULL) {
if (error_pos != NULL)
*error_pos = (size_t)-1;
return NULL;
}
bytes = result;
}
return result;
#endif /* __APPLE__ or __ANDROID__ */
}
#ifdef MS_WINDOWS
static __int64 secs_between_epochs = 11644473600; /* Seconds between 1.1.1601 and 1.1.1970 */
static void
FILE_TIME_to_time_t_nsec(FILETIME *in_ptr, time_t *time_out, int* nsec_out)
{
/* XXX endianness. Shouldn't matter, as all Windows implementations are little-endian */
/* Cannot simply cast and dereference in_ptr,
since it might not be aligned properly */
__int64 in;
memcpy(&in, in_ptr, sizeof(in));
*nsec_out = (int)(in % 10000000) * 100; /* FILETIME is in units of 100 nsec. */
*time_out = Py_SAFE_DOWNCAST((in / 10000000) - secs_between_epochs, __int64, time_t);
}
void
_Py_time_t_to_FILE_TIME(time_t time_in, int nsec_in, FILETIME *out_ptr)
{
/* XXX endianness */
__int64 out;
out = time_in + secs_between_epochs;
out = out * 10000000 + nsec_in / 100;
memcpy(out_ptr, &out, sizeof(out));
}
/* Below, we *know* that ugo+r is 0444 */
#if _S_IREAD != 0400
#error Unsupported C library
#endif
static int
attributes_to_mode(DWORD attr)
{
int m = 0;
if (attr & FILE_ATTRIBUTE_DIRECTORY)
m |= _S_IFDIR | 0111; /* IFEXEC for user,group,other */
else
m |= _S_IFREG;
if (attr & FILE_ATTRIBUTE_READONLY)
m |= 0444;
else
m |= 0666;
return m;
}
void
_Py_attribute_data_to_stat(BY_HANDLE_FILE_INFORMATION *info, ULONG reparse_tag,
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_nlink = info->nNumberOfLinks;
result->st_ino = (((__int64)info->nFileIndexHigh)<<32) + info->nFileIndexLow;
if (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;
}
result->st_file_attributes = info->dwFileAttributes;
}
#endif
/* Return information about a file.
On POSIX, use fstat().
On Windows, use GetFileType() and GetFileInformationByHandle() which support
files larger than 2 GB. fstat() may fail with EOVERFLOW on files larger
than 2 GB because the file size type is a signed 32-bit integer: see issue
#23152.
On Windows, set the last Windows error and return nonzero on error. On
POSIX, set errno and return nonzero on error. Fill status and return 0 on
success. */
int
_Py_fstat_noraise(int fd, struct _Py_stat_struct *status)
{
#ifdef MS_WINDOWS
BY_HANDLE_FILE_INFORMATION info;
HANDLE h;
int type;
_Py_BEGIN_SUPPRESS_IPH
h = (HANDLE)_get_osfhandle(fd);
_Py_END_SUPPRESS_IPH
if (h == INVALID_HANDLE_VALUE) {
/* errno is already set by _get_osfhandle, but we also set
the Win32 error for callers who expect that */
SetLastError(ERROR_INVALID_HANDLE);
return -1;
}
memset(status, 0, sizeof(*status));
type = GetFileType(h);
if (type == FILE_TYPE_UNKNOWN) {
DWORD error = GetLastError();
if (error != 0) {
errno = winerror_to_errno(error);
return -1;
}
/* else: valid but unknown file */
}
if (type != FILE_TYPE_DISK) {
if (type == FILE_TYPE_CHAR)
status->st_mode = _S_IFCHR;
else if (type == FILE_TYPE_PIPE)
status->st_mode = _S_IFIFO;
return 0;
}
if (!GetFileInformationByHandle(h, &info)) {
/* 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);
/* specific to fstat() */
status->st_ino = (((__int64)info.nFileIndexHigh)<<32) + info.nFileIndexLow;
return 0;
#else
return fstat(fd, status);
#endif
}
/* Return information about a file.
On POSIX, use fstat().
On Windows, use GetFileType() and GetFileInformationByHandle() which support
files larger than 2 GB. fstat() may fail with EOVERFLOW on files larger
than 2 GB because the file size type is a signed 32-bit integer: see issue
#23152.
Raise an exception and return -1 on error. On Windows, set the last Windows
error on error. On POSIX, set errno on error. Fill status and return 0 on
success.
Release the GIL to call GetFileType() and GetFileInformationByHandle(), or
to call fstat(). The caller must hold the GIL. */
int
_Py_fstat(int fd, struct _Py_stat_struct *status)
{
int res;
#ifdef WITH_THREAD
assert(PyGILState_Check());
#endif
Py_BEGIN_ALLOW_THREADS
res = _Py_fstat_noraise(fd, status);
Py_END_ALLOW_THREADS
if (res != 0) {
#ifdef MS_WINDOWS
PyErr_SetFromWindowsErr(0);
#else
PyErr_SetFromErrno(PyExc_OSError);
#endif
return -1;
}
return 0;
}
/* Call _wstat() on Windows, or encode the path to the filesystem encoding and
call stat() otherwise. Only fill st_mode attribute on Windows.
Return 0 on success, -1 on _wstat() / stat() error, -2 if an exception was
raised. */
int
_Py_stat(PyObject *path, struct stat *statbuf)
{
#ifdef MS_WINDOWS
int err;
struct _stat wstatbuf;
wchar_t *wpath;
wpath = PyUnicode_AsUnicode(path);
if (wpath == NULL)
return -2;
err = _wstat(wpath, &wstatbuf);
if (!err)
statbuf->st_mode = wstatbuf.st_mode;
return err;
#else
int ret;
PyObject *bytes = PyUnicode_EncodeFSDefault(path);
if (bytes == NULL)
return -2;
ret = stat(PyBytes_AS_STRING(bytes), statbuf);
Py_DECREF(bytes);
return ret;
#endif
}
static int
get_inheritable(int fd, int raise)
{
#ifdef MS_WINDOWS
HANDLE handle;
DWORD flags;
_Py_BEGIN_SUPPRESS_IPH
handle = (HANDLE)_get_osfhandle(fd);
_Py_END_SUPPRESS_IPH
if (handle == INVALID_HANDLE_VALUE) {
if (raise)
PyErr_SetFromErrno(PyExc_OSError);
return -1;
}
if (!GetHandleInformation(handle, &flags)) {
if (raise)
PyErr_SetFromWindowsErr(0);
return -1;
}
return (flags & HANDLE_FLAG_INHERIT);
#else
int flags;
flags = fcntl(fd, F_GETFD, 0);
if (flags == -1) {
if (raise)
PyErr_SetFromErrno(PyExc_OSError);
return -1;
}
return !(flags & FD_CLOEXEC);
#endif
}
/* Get the inheritable flag of the specified file descriptor.
Return 1 if the file descriptor can be inherited, 0 if it cannot,
raise an exception and return -1 on error. */
int
_Py_get_inheritable(int fd)
{
return get_inheritable(fd, 1);
}
static int
set_inheritable(int fd, int inheritable, int raise, int *atomic_flag_works)
{
#ifdef MS_WINDOWS
HANDLE handle;
DWORD flags;
#else
#if defined(HAVE_SYS_IOCTL_H) && defined(FIOCLEX) && defined(FIONCLEX)
static int ioctl_works = -1;
int request;
int err;
#endif
int flags, new_flags;
int res;
#endif
/* atomic_flag_works can only be used to make the file descriptor
non-inheritable */
assert(!(atomic_flag_works != NULL && inheritable));
if (atomic_flag_works != NULL && !inheritable) {
if (*atomic_flag_works == -1) {
int isInheritable = get_inheritable(fd, raise);
if (isInheritable == -1)
return -1;
*atomic_flag_works = !isInheritable;
}
if (*atomic_flag_works)
return 0;
}
#ifdef MS_WINDOWS
_Py_BEGIN_SUPPRESS_IPH
handle = (HANDLE)_get_osfhandle(fd);
_Py_END_SUPPRESS_IPH
if (handle == INVALID_HANDLE_VALUE) {
if (raise)
PyErr_SetFromErrno(PyExc_OSError);
return -1;
}
if (inheritable)
flags = HANDLE_FLAG_INHERIT;
else
flags = 0;
if (!SetHandleInformation(handle, HANDLE_FLAG_INHERIT, flags)) {
if (raise)
PyErr_SetFromWindowsErr(0);
return -1;
}
return 0;
#else
#if defined(HAVE_SYS_IOCTL_H) && defined(FIOCLEX) && defined(FIONCLEX)
if (ioctl_works != 0) {
/* fast-path: ioctl() only requires one syscall */
if (inheritable)
request = FIONCLEX;
else
request = FIOCLEX;
err = ioctl(fd, request, NULL);
if (!err) {
ioctl_works = 1;
return 0;
}
if (errno != ENOTTY && errno != EACCES) {
if (raise)
PyErr_SetFromErrno(PyExc_OSError);
return -1;
}
else {
/* Issue #22258: Here, ENOTTY means "Inappropriate ioctl for
device". The ioctl is declared but not supported by the kernel.
Remember that ioctl() doesn't work. It is the case on
Illumos-based OS for example.
Issue #27057: When SELinux policy disallows ioctl it will fail
with EACCES. While FIOCLEX is safe operation it may be
unavailable because ioctl was denied altogether.
This can be the case on Android. */
ioctl_works = 0;
}
/* fallback to fcntl() if ioctl() does not work */
}
#endif
/* slow-path: fcntl() requires two syscalls */
flags = fcntl(fd, F_GETFD);
if (flags < 0) {
if (raise)
PyErr_SetFromErrno(PyExc_OSError);
return -1;
}
if (inheritable) {
new_flags = flags & ~FD_CLOEXEC;
}
else {
new_flags = flags | FD_CLOEXEC;
}
if (new_flags == flags) {
/* FD_CLOEXEC flag already set/cleared: nothing to do */
return 0;
}
res = fcntl(fd, F_SETFD, new_flags);
if (res < 0) {
if (raise)
PyErr_SetFromErrno(PyExc_OSError);
return -1;
}
return 0;
#endif
}
/* Make the file descriptor non-inheritable.
Return 0 on success, set errno and return -1 on error. */
static int
make_non_inheritable(int fd)
{
return set_inheritable(fd, 0, 0, NULL);
}
/* Set the inheritable flag of the specified file descriptor.
On success: return 0, on error: raise an exception if raise is nonzero
and return -1.
If atomic_flag_works is not NULL:
* if *atomic_flag_works==-1, check if the inheritable is set on the file
descriptor: if yes, set *atomic_flag_works to 1, otherwise set to 0 and
set the inheritable flag
* if *atomic_flag_works==1: do nothing
* if *atomic_flag_works==0: set inheritable flag to False
Set atomic_flag_works to NULL if no atomic flag was used to create the
file descriptor.
atomic_flag_works can only be used to make a file descriptor
non-inheritable: atomic_flag_works must be NULL if inheritable=1. */
int
_Py_set_inheritable(int fd, int inheritable, int *atomic_flag_works)
{
return set_inheritable(fd, inheritable, 1, atomic_flag_works);
}
static int
_Py_open_impl(const char *pathname, int flags, int gil_held)
{
int fd;
int async_err = 0;
#ifndef MS_WINDOWS
int *atomic_flag_works;
#endif
#ifdef MS_WINDOWS
flags |= O_NOINHERIT;
#elif defined(O_CLOEXEC)
atomic_flag_works = &_Py_open_cloexec_works;
flags |= O_CLOEXEC;
#else
atomic_flag_works = NULL;
#endif
if (gil_held) {
do {
Py_BEGIN_ALLOW_THREADS
fd = open(pathname, flags);
Py_END_ALLOW_THREADS
} while (fd < 0
&& errno == EINTR && !(async_err = PyErr_CheckSignals()));
if (async_err)
return -1;
if (fd < 0) {
PyErr_SetFromErrnoWithFilename(PyExc_OSError, pathname);
return -1;
}
}
else {
fd = open(pathname, flags);
if (fd < 0)
return -1;
}
#ifndef MS_WINDOWS
if (set_inheritable(fd, 0, gil_held, atomic_flag_works) < 0) {
close(fd);
return -1;
}
#endif
return fd;
}
/* Open a file with the specified flags (wrapper to open() function).
Return a file descriptor on success. Raise an exception and return -1 on
error.
The file descriptor is created non-inheritable.
When interrupted by a signal (open() fails with EINTR), retry the syscall,
except if the Python signal handler raises an exception.
Release the GIL to call open(). The caller must hold the GIL. */
int
_Py_open(const char *pathname, int flags)
{
#ifdef WITH_THREAD
/* _Py_open() must be called with the GIL held. */
assert(PyGILState_Check());
#endif
return _Py_open_impl(pathname, flags, 1);
}
/* Open a file with the specified flags (wrapper to open() function).
Return a file descriptor on success. Set errno and return -1 on error.
The file descriptor is created non-inheritable.
If interrupted by a signal, fail with EINTR. */
int
_Py_open_noraise(const char *pathname, int flags)
{
return _Py_open_impl(pathname, flags, 0);
}
/* Open a file. Use _wfopen() on Windows, encode the path to the locale
encoding and use fopen() otherwise.
The file descriptor is created non-inheritable.
If interrupted by a signal, fail with EINTR. */
FILE *
_Py_wfopen(const wchar_t *path, const wchar_t *mode)
{
FILE *f;
#ifndef MS_WINDOWS
char *cpath;
char cmode[10];
size_t r;
r = wcstombs(cmode, mode, 10);
if (r == (size_t)-1 || r >= 10) {
errno = EINVAL;
return NULL;
}
cpath = Py_EncodeLocale(path, NULL);
if (cpath == NULL)
return NULL;
f = fopen(cpath, cmode);
PyMem_Free(cpath);
#else
f = _wfopen(path, mode);
#endif
if (f == NULL)
return NULL;
if (make_non_inheritable(fileno(f)) < 0) {
fclose(f);
return NULL;
}
return f;
}
/* Wrapper to fopen().
The file descriptor is created non-inheritable.
If interrupted by a signal, fail with EINTR. */
FILE*
_Py_fopen(const char *pathname, const char *mode)
{
FILE *f = fopen(pathname, mode);
if (f == NULL)
return NULL;
if (make_non_inheritable(fileno(f)) < 0) {
fclose(f);
return NULL;
}
return f;
}
/* Open a file. Call _wfopen() on Windows, or encode the path to the filesystem
encoding and call fopen() otherwise.
Return the new file object on success. Raise an exception and return NULL
on error.
The file descriptor is created non-inheritable.
When interrupted by a signal (open() fails with EINTR), retry the syscall,
except if the Python signal handler raises an exception.
Release the GIL to call _wfopen() or fopen(). The caller must hold
the GIL. */
FILE*
_Py_fopen_obj(PyObject *path, const char *mode)
{
FILE *f;
int async_err = 0;
#ifdef MS_WINDOWS
wchar_t *wpath;
wchar_t wmode[10];
int usize;
#ifdef WITH_THREAD
assert(PyGILState_Check());
#endif
if (!PyUnicode_Check(path)) {
PyErr_Format(PyExc_TypeError,
"str file path expected under Windows, got %R",
Py_TYPE(path));
return NULL;
}
wpath = PyUnicode_AsUnicode(path);
if (wpath == NULL)
return NULL;
usize = MultiByteToWideChar(CP_ACP, 0, mode, -1, wmode, sizeof(wmode));
if (usize == 0) {
PyErr_SetFromWindowsErr(0);
return NULL;
}
do {
Py_BEGIN_ALLOW_THREADS
f = _wfopen(wpath, wmode);
Py_END_ALLOW_THREADS
} while (f == NULL
&& errno == EINTR && !(async_err = PyErr_CheckSignals()));
#else
PyObject *bytes;
char *path_bytes;
#ifdef WITH_THREAD
assert(PyGILState_Check());
#endif
if (!PyUnicode_FSConverter(path, &bytes))
return NULL;
path_bytes = PyBytes_AS_STRING(bytes);
do {
Py_BEGIN_ALLOW_THREADS
f = fopen(path_bytes, mode);
Py_END_ALLOW_THREADS
} while (f == NULL
&& errno == EINTR && !(async_err = PyErr_CheckSignals()));
Py_DECREF(bytes);
#endif
if (async_err)
return NULL;
if (f == NULL) {
PyErr_SetFromErrnoWithFilenameObject(PyExc_OSError, path);
return NULL;
}
if (set_inheritable(fileno(f), 0, 1, NULL) < 0) {
fclose(f);
return NULL;
}
return f;
}
/* Read count bytes from fd into buf.
On success, return the number of read bytes, it can be lower than count.
If the current file offset is at or past the end of file, no bytes are read,
and read() returns zero.
On error, raise an exception, set errno and return -1.
When interrupted by a signal (read() fails with EINTR), retry the syscall.
If the Python signal handler raises an exception, the function returns -1
(the syscall is not retried).
Release the GIL to call read(). The caller must hold the GIL. */
Py_ssize_t
_Py_read(int fd, void *buf, size_t count)
{
Py_ssize_t n;
int err;
int async_err = 0;
#ifdef WITH_THREAD
assert(PyGILState_Check());
#endif
/* _Py_read() must not be called with an exception set, otherwise the
* caller may think that read() was interrupted by a signal and the signal
* handler raised an exception. */
assert(!PyErr_Occurred());
#ifdef MS_WINDOWS
if (count > INT_MAX) {
/* On Windows, the count parameter of read() is an int */
count = INT_MAX;
}
#else
if (count > PY_SSIZE_T_MAX) {
/* if count is greater than PY_SSIZE_T_MAX,
* read() result is undefined */
count = PY_SSIZE_T_MAX;
}
#endif
_Py_BEGIN_SUPPRESS_IPH
do {
Py_BEGIN_ALLOW_THREADS
errno = 0;
#ifdef MS_WINDOWS
n = read(fd, buf, (int)count);
#else
n = read(fd, buf, count);
#endif
/* save/restore errno because PyErr_CheckSignals()
* and PyErr_SetFromErrno() can modify it */
err = errno;
Py_END_ALLOW_THREADS
} while (n < 0 && err == EINTR &&
!(async_err = PyErr_CheckSignals()));
_Py_END_SUPPRESS_IPH
if (async_err) {
/* read() was interrupted by a signal (failed with EINTR)
* and the Python signal handler raised an exception */
errno = err;
assert(errno == EINTR && PyErr_Occurred());
return -1;
}
if (n < 0) {
PyErr_SetFromErrno(PyExc_OSError);
errno = err;
return -1;
}
return n;
}
static Py_ssize_t
_Py_write_impl(int fd, const void *buf, size_t count, int gil_held)
{
Py_ssize_t n;
int err;
int async_err = 0;
_Py_BEGIN_SUPPRESS_IPH
#ifdef MS_WINDOWS
if (count > 32767 && isatty(fd)) {
/* Issue #11395: the Windows console returns an error (12: not
enough space error) on writing into stdout if stdout mode is
binary and the length is greater than 66,000 bytes (or less,
depending on heap usage). */
count = 32767;
}
else if (count > INT_MAX)
count = INT_MAX;
#else
if (count > PY_SSIZE_T_MAX) {
/* write() should truncate count to PY_SSIZE_T_MAX, but it's safer
* to do it ourself to have a portable behaviour. */
count = PY_SSIZE_T_MAX;
}
#endif
if (gil_held) {
do {
Py_BEGIN_ALLOW_THREADS
errno = 0;
#ifdef MS_WINDOWS
n = write(fd, buf, (int)count);
#else
n = write(fd, buf, count);
#endif
/* save/restore errno because PyErr_CheckSignals()
* and PyErr_SetFromErrno() can modify it */
err = errno;
Py_END_ALLOW_THREADS
} while (n < 0 && err == EINTR &&
!(async_err = PyErr_CheckSignals()));
}
else {
do {
errno = 0;
#ifdef MS_WINDOWS
n = write(fd, buf, (int)count);
#else
n = write(fd, buf, count);
#endif
err = errno;
} while (n < 0 && err == EINTR);
}
_Py_END_SUPPRESS_IPH
if (async_err) {
/* write() was interrupted by a signal (failed with EINTR)
and the Python signal handler raised an exception (if gil_held is
nonzero). */
errno = err;
assert(errno == EINTR && (!gil_held || PyErr_Occurred()));
return -1;
}
if (n < 0) {
if (gil_held)
PyErr_SetFromErrno(PyExc_OSError);
errno = err;
return -1;
}
return n;
}
/* Write count bytes of buf into fd.
On success, return the number of written bytes, it can be lower than count
including 0. On error, raise an exception, set errno and return -1.
When interrupted by a signal (write() fails with EINTR), retry the syscall.
If the Python signal handler raises an exception, the function returns -1
(the syscall is not retried).
Release the GIL to call write(). The caller must hold the GIL. */
Py_ssize_t
_Py_write(int fd, const void *buf, size_t count)
{
#ifdef WITH_THREAD
assert(PyGILState_Check());
#endif
/* _Py_write() must not be called with an exception set, otherwise the
* caller may think that write() was interrupted by a signal and the signal
* handler raised an exception. */
assert(!PyErr_Occurred());
return _Py_write_impl(fd, buf, count, 1);
}
/* Write count bytes of buf into fd.
*
* On success, return the number of written bytes, it can be lower than count
* including 0. On error, set errno and return -1.
*
* When interrupted by a signal (write() fails with EINTR), retry the syscall
* without calling the Python signal handler. */
Py_ssize_t
_Py_write_noraise(int fd, const void *buf, size_t count)
{
return _Py_write_impl(fd, buf, count, 0);
}
#ifdef HAVE_READLINK
/* Read value of symbolic link. Encode the path to the locale encoding, decode
the result from the locale encoding. Return -1 on error. */
int
_Py_wreadlink(const wchar_t *path, wchar_t *buf, size_t bufsiz)
{
char *cpath;
char cbuf[MAXPATHLEN];
wchar_t *wbuf;
int res;
size_t r1;
cpath = Py_EncodeLocale(path, NULL);
if (cpath == NULL) {
errno = EINVAL;
return -1;
}
res = (int)readlink(cpath, cbuf, Py_ARRAY_LENGTH(cbuf));
PyMem_Free(cpath);
if (res == -1)
return -1;
if (res == Py_ARRAY_LENGTH(cbuf)) {
errno = EINVAL;
return -1;
}
cbuf[res] = '\0'; /* buf will be null terminated */
wbuf = Py_DecodeLocale(cbuf, &r1);
if (wbuf == NULL) {
errno = EINVAL;
return -1;
}
if (bufsiz <= r1) {
PyMem_RawFree(wbuf);
errno = EINVAL;
return -1;
}
wcsncpy(buf, wbuf, bufsiz);
PyMem_RawFree(wbuf);
return (int)r1;
}
#endif
#ifdef HAVE_REALPATH
/* Return the canonicalized absolute pathname. Encode path to the locale
encoding, decode the result from the locale encoding.
Return NULL on error. */
wchar_t*
_Py_wrealpath(const wchar_t *path,
wchar_t *resolved_path, size_t resolved_path_size)
{
char *cpath;
char cresolved_path[MAXPATHLEN];
wchar_t *wresolved_path;
char *res;
size_t r;
cpath = Py_EncodeLocale(path, NULL);
if (cpath == NULL) {
errno = EINVAL;
return NULL;
}
res = realpath(cpath, cresolved_path);
PyMem_Free(cpath);
if (res == NULL)
return NULL;
wresolved_path = Py_DecodeLocale(cresolved_path, &r);
if (wresolved_path == NULL) {
errno = EINVAL;
return NULL;
}
if (resolved_path_size <= r) {
PyMem_RawFree(wresolved_path);
errno = EINVAL;
return NULL;
}
wcsncpy(resolved_path, wresolved_path, resolved_path_size);
PyMem_RawFree(wresolved_path);
return resolved_path;
}
#endif
/* Get the current directory. size is the buffer size in wide characters
including the null character. Decode the path from the locale encoding.
Return NULL on error. */
wchar_t*
_Py_wgetcwd(wchar_t *buf, size_t size)
{
#ifdef MS_WINDOWS
int isize = (int)Py_MIN(size, INT_MAX);
return _wgetcwd(buf, isize);
#else
char fname[MAXPATHLEN];
wchar_t *wname;
size_t len;
if (getcwd(fname, Py_ARRAY_LENGTH(fname)) == NULL)
return NULL;
wname = Py_DecodeLocale(fname, &len);
if (wname == NULL)
return NULL;
if (size <= len) {
PyMem_RawFree(wname);
return NULL;
}
wcsncpy(buf, wname, size);
PyMem_RawFree(wname);
return buf;
#endif
}
/* Duplicate a file descriptor. The new file descriptor is created as
non-inheritable. Return a new file descriptor on success, raise an OSError
exception and return -1 on error.
The GIL is released to call dup(). The caller must hold the GIL. */
int
_Py_dup(int fd)
{
#ifdef MS_WINDOWS
HANDLE handle;
DWORD ftype;
#endif
#ifdef WITH_THREAD
assert(PyGILState_Check());
#endif
#ifdef MS_WINDOWS
_Py_BEGIN_SUPPRESS_IPH
handle = (HANDLE)_get_osfhandle(fd);
_Py_END_SUPPRESS_IPH
if (handle == INVALID_HANDLE_VALUE) {
PyErr_SetFromErrno(PyExc_OSError);
return -1;
}
/* get the file type, ignore the error if it failed */
ftype = GetFileType(handle);
Py_BEGIN_ALLOW_THREADS
_Py_BEGIN_SUPPRESS_IPH
fd = dup(fd);
_Py_END_SUPPRESS_IPH
Py_END_ALLOW_THREADS
if (fd < 0) {
PyErr_SetFromErrno(PyExc_OSError);
return -1;
}
/* Character files like console cannot be make non-inheritable */
if (ftype != FILE_TYPE_CHAR) {
if (_Py_set_inheritable(fd, 0, NULL) < 0) {
_Py_BEGIN_SUPPRESS_IPH
close(fd);
_Py_END_SUPPRESS_IPH
return -1;
}
}
#elif defined(HAVE_FCNTL_H) && defined(F_DUPFD_CLOEXEC)
Py_BEGIN_ALLOW_THREADS
_Py_BEGIN_SUPPRESS_IPH
fd = fcntl(fd, F_DUPFD_CLOEXEC, 0);
_Py_END_SUPPRESS_IPH
Py_END_ALLOW_THREADS
if (fd < 0) {
PyErr_SetFromErrno(PyExc_OSError);
return -1;
}
#else
Py_BEGIN_ALLOW_THREADS
_Py_BEGIN_SUPPRESS_IPH
fd = dup(fd);
_Py_END_SUPPRESS_IPH
Py_END_ALLOW_THREADS
if (fd < 0) {
PyErr_SetFromErrno(PyExc_OSError);
return -1;
}
if (_Py_set_inheritable(fd, 0, NULL) < 0) {
_Py_BEGIN_SUPPRESS_IPH
close(fd);
_Py_END_SUPPRESS_IPH
return -1;
}
#endif
return fd;
}
#ifndef MS_WINDOWS
/* Get the blocking mode of the file descriptor.
Return 0 if the O_NONBLOCK flag is set, 1 if the flag is cleared,
raise an exception and return -1 on error. */
int
_Py_get_blocking(int fd)
{
int flags;
_Py_BEGIN_SUPPRESS_IPH
flags = fcntl(fd, F_GETFL, 0);
_Py_END_SUPPRESS_IPH
if (flags < 0) {
PyErr_SetFromErrno(PyExc_OSError);
return -1;
}
return !(flags & O_NONBLOCK);
}
/* Set the blocking mode of the specified file descriptor.
Set the O_NONBLOCK flag if blocking is False, clear the O_NONBLOCK flag
otherwise.
Return 0 on success, raise an exception and return -1 on error. */
int
_Py_set_blocking(int fd, int blocking)
{
#if defined(HAVE_SYS_IOCTL_H) && defined(FIONBIO)
int arg = !blocking;
if (ioctl(fd, FIONBIO, &arg) < 0)
goto error;
#else
int flags, res;
_Py_BEGIN_SUPPRESS_IPH
flags = fcntl(fd, F_GETFL, 0);
if (flags >= 0) {
if (blocking)
flags = flags & (~O_NONBLOCK);
else
flags = flags | O_NONBLOCK;
res = fcntl(fd, F_SETFL, flags);
} else {
res = -1;
}
_Py_END_SUPPRESS_IPH
if (res < 0)
goto error;
#endif
return 0;
error:
PyErr_SetFromErrno(PyExc_OSError);
return -1;
}
#endif
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