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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>
#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 */
#ifdef __APPLE__
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(), 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
if (!_PyVerify_fd(fd) || !isatty(fd)) {
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[100];
int is_ascii;
unsigned int i;
char* ascii_aliases[] = {
"ascii",
"646",
"ansi-x3.4-1968",
"ansi-x3-4-1968",
"ansi-x3.4-1986",
"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 occured, 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)
{
#ifdef __APPLE__
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__ */
}
/* 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)
{
#ifdef __APPLE__
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__ */
}
/* In principle, this should use HAVE__WSTAT, and _wstat
should be detected by autoconf. However, no current
POSIX system provides that function, so testing for
it is pointless.
Not sure whether the MS_WINDOWS guards are necessary:
perhaps for cygwin/mingw builds?
*/
#if defined(HAVE_STAT) && !defined(MS_WINDOWS)
/* Get file status. Encode the path to the locale encoding. */
int
_Py_wstat(const wchar_t* path, struct stat *buf)
{
int err;
char *fname;
fname = Py_EncodeLocale(path, NULL);
if (fname == NULL) {
errno = EINVAL;
return -1;
}
err = stat(fname, buf);
PyMem_Free(fname);
return err;
}
#endif
#if defined(HAVE_FSTAT) || defined(MS_WINDOWS)
#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 an signed 32-bit integer: see issue
#23152.
*/
int
_Py_fstat(int fd, struct _Py_stat_struct *result)
{
#ifdef MS_WINDOWS
BY_HANDLE_FILE_INFORMATION info;
HANDLE h;
int type;
if (!_PyVerify_fd(fd))
h = INVALID_HANDLE_VALUE;
else
h = (HANDLE)_get_osfhandle(fd);
/* Protocol violation: we explicitly clear errno, instead of
setting it to a POSIX error. Callers should use GetLastError. */
errno = 0;
if (h == INVALID_HANDLE_VALUE) {
/* This is really a C library error (invalid file handle).
We set the Win32 error to the closes one matching. */
SetLastError(ERROR_INVALID_HANDLE);
return -1;
}
memset(result, 0, sizeof(*result));
type = GetFileType(h);
if (type == FILE_TYPE_UNKNOWN) {
DWORD error = GetLastError();
if (error != 0) {
return -1;
}
/* else: valid but unknown file */
}
if (type != FILE_TYPE_DISK) {
if (type == FILE_TYPE_CHAR)
result->st_mode = _S_IFCHR;
else if (type == FILE_TYPE_PIPE)
result->st_mode = _S_IFIFO;
return 0;
}
if (!GetFileInformationByHandle(h, &info)) {
return -1;
}
_Py_attribute_data_to_stat(&info, 0, result);
/* specific to fstat() */
result->st_ino = (((__int64)info.nFileIndexHigh)<<32) + info.nFileIndexLow;
return 0;
#else
return fstat(fd, result);
#endif
}
#endif /* HAVE_FSTAT || MS_WINDOWS */
#ifdef HAVE_STAT
/* 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
}
#endif /* HAVE_STAT */
static int
get_inheritable(int fd, int raise)
{
#ifdef MS_WINDOWS
HANDLE handle;
DWORD flags;
if (!_PyVerify_fd(fd)) {
if (raise)
PyErr_SetFromErrno(PyExc_OSError);
return -1;
}
handle = (HANDLE)_get_osfhandle(fd);
if (handle == INVALID_HANDLE_VALUE) {
if (raise)
PyErr_SetFromWindowsErr(0);
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;
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 inheritable = get_inheritable(fd, raise);
if (inheritable == -1)
return -1;
*atomic_flag_works = !inheritable;
}
if (*atomic_flag_works)
return 0;
}
#ifdef MS_WINDOWS
if (!_PyVerify_fd(fd)) {
if (raise)
PyErr_SetFromErrno(PyExc_OSError);
return -1;
}
handle = (HANDLE)_get_osfhandle(fd);
if (handle == INVALID_HANDLE_VALUE) {
if (raise)
PyErr_SetFromWindowsErr(0);
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) {
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. */
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)
flags &= ~FD_CLOEXEC;
else
flags |= FD_CLOEXEC;
res = fcntl(fd, F_SETFD, 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);
}
/* Open a file with the specified flags (wrapper to open() function).
The file descriptor is created non-inheritable. */
int
_Py_open(const char *pathname, int flags)
{
int fd;
#ifdef MS_WINDOWS
fd = open(pathname, flags | O_NOINHERIT);
if (fd < 0)
return fd;
#else
int *atomic_flag_works;
#ifdef O_CLOEXEC
atomic_flag_works = &_Py_open_cloexec_works;
flags |= O_CLOEXEC;
#else
atomic_flag_works = NULL;
#endif
fd = open(pathname, flags);
if (fd < 0)
return fd;
if (set_inheritable(fd, 0, 0, atomic_flag_works) < 0) {
close(fd);
return -1;
}
#endif /* !MS_WINDOWS */
return fd;
}
/* 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. */
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. */
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. The file descriptor is created
non-inheritable.
Return the new file object on success, or NULL if the file cannot be open or
(if PyErr_Occurred()) on unicode error. */
FILE*
_Py_fopen_obj(PyObject *path, const char *mode)
{
FILE *f;
#ifdef MS_WINDOWS
wchar_t *wpath;
wchar_t wmode[10];
int usize;
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)
return NULL;
f = _wfopen(wpath, wmode);
#else
PyObject *bytes;
if (!PyUnicode_FSConverter(path, &bytes))
return NULL;
f = fopen(PyBytes_AS_STRING(bytes), mode);
Py_DECREF(bytes);
#endif
if (f == NULL)
return NULL;
if (make_non_inheritable(fileno(f)) < 0) {
fclose(f);
return NULL;
}
return f;
}
#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
if (!_PyVerify_fd(fd)) {
PyErr_SetFromErrno(PyExc_OSError);
return -1;
}
#ifdef MS_WINDOWS
handle = (HANDLE)_get_osfhandle(fd);
if (handle == INVALID_HANDLE_VALUE) {
PyErr_SetFromWindowsErr(0);
return -1;
}
/* get the file type, ignore the error if it failed */
ftype = GetFileType(handle);
Py_BEGIN_ALLOW_THREADS
fd = dup(fd);
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) {
close(fd);
return -1;
}
}
#elif defined(HAVE_FCNTL_H) && defined(F_DUPFD_CLOEXEC)
Py_BEGIN_ALLOW_THREADS
fd = fcntl(fd, F_DUPFD_CLOEXEC, 0);
Py_END_ALLOW_THREADS
if (fd < 0) {
PyErr_SetFromErrno(PyExc_OSError);
return -1;
}
#else
Py_BEGIN_ALLOW_THREADS
fd = dup(fd);
Py_END_ALLOW_THREADS
if (fd < 0) {
PyErr_SetFromErrno(PyExc_OSError);
return -1;
}
if (_Py_set_inheritable(fd, 0, NULL) < 0) {
close(fd);
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 = fcntl(fd, F_GETFL, 0);
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;
flags = fcntl(fd, F_GETFL, 0);
if (flags < 0)
goto error;
if (blocking)
flags = flags & (~O_NONBLOCK);
else
flags = flags | O_NONBLOCK;
res = fcntl(fd, F_SETFL, flags);
if (res < 0)
goto error;
#endif
return 0;
error:
PyErr_SetFromErrno(PyExc_OSError);
return -1;
}
#endif
#ifdef _MSC_VER
#if _MSC_VER >= 1900
/* This function lets the Windows CRT validate the file handle without
terminating the process if it's invalid. */
int
_PyVerify_fd(int fd)
{
intptr_t osh;
/* Fast check for the only condition we know */
if (fd < 0) {
_set_errno(EBADF);
return 0;
}
osh = _get_osfhandle(fd);
return osh != (intptr_t)-1;
}
#elif _MSC_VER >= 1400
/* Legacy implementation of _PyVerify_fd while transitioning to
* MSVC 14.0. This should eventually be removed. (issue23524)
*/
/* Microsoft CRT in VS2005 and higher will verify that a filehandle is
* valid and raise an assertion if it isn't.
* Normally, an invalid fd is likely to be a C program error and therefore
* an assertion can be useful, but it does contradict the POSIX standard
* which for write(2) states:
* "Otherwise, -1 shall be returned and errno set to indicate the error."
* "[EBADF] The fildes argument is not a valid file descriptor open for
* writing."
* Furthermore, python allows the user to enter any old integer
* as a fd and should merely raise a python exception on error.
* The Microsoft CRT doesn't provide an official way to check for the
* validity of a file descriptor, but we can emulate its internal behaviour
* by using the exported __pinfo data member and knowledge of the
* internal structures involved.
* The structures below must be updated for each version of visual studio
* according to the file internal.h in the CRT source, until MS comes
* up with a less hacky way to do this.
* (all of this is to avoid globally modifying the CRT behaviour using
* _set_invalid_parameter_handler() and _CrtSetReportMode())
*/
/* The actual size of the structure is determined at runtime.
* Only the first items must be present.
*/
typedef struct {
intptr_t osfhnd;
char osfile;
} my_ioinfo;
extern __declspec(dllimport) char * __pioinfo[];
#define IOINFO_L2E 5
#define IOINFO_ARRAYS 64
#define IOINFO_ARRAY_ELTS (1 << IOINFO_L2E)
#define _NHANDLE_ (IOINFO_ARRAYS * IOINFO_ARRAY_ELTS)
#define FOPEN 0x01
#define _NO_CONSOLE_FILENO (intptr_t)-2
/* This function emulates what the windows CRT does to validate file handles */
int
_PyVerify_fd(int fd)
{
const int i1 = fd >> IOINFO_L2E;
const int i2 = fd & ((1 << IOINFO_L2E) - 1);
static size_t sizeof_ioinfo = 0;
/* Determine the actual size of the ioinfo structure,
* as used by the CRT loaded in memory
*/
if (sizeof_ioinfo == 0 && __pioinfo[0] != NULL) {
sizeof_ioinfo = _msize(__pioinfo[0]) / IOINFO_ARRAY_ELTS;
}
if (sizeof_ioinfo == 0) {
/* This should not happen... */
goto fail;
}
/* See that it isn't a special CLEAR fileno */
if (fd != _NO_CONSOLE_FILENO) {
/* Microsoft CRT would check that 0<=fd<_nhandle but we can't do that. Instead
* we check pointer validity and other info
*/
if (0 <= i1 && i1 < IOINFO_ARRAYS && __pioinfo[i1] != NULL) {
/* finally, check that the file is open */
my_ioinfo* info = (my_ioinfo*)(__pioinfo[i1] + i2 * sizeof_ioinfo);
if (info->osfile & FOPEN) {
return 1;
}
}
}
fail:
errno = EBADF;
return 0;
}
#endif /* _MSC_VER >= 1900 || _MSC_VER >= 1400 */
#endif /* defined _MSC_VER */
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