static int __cdecl dup2_nolock(int const source_fh, int const target_fh) throw()
{
if ((_osfile(source_fh) & FOPEN) == 0)
{
// If the source handle is not open, return an error. Noe that the
// DuplicateHandle API will not detect this error, because it implies
// that _osfhnd(source_fh) == INVALID_HANDLE_VALUE, and this is a
// legal HANDLE value to be duplicated.
errno = EBADF;
_doserrno = 0;
_ASSERTE(("Invalid file descriptor. File possibly closed by a different thread",0));
return -1;
}
// If the target is open, close it first. We ignore the possibility of an
// error here: an error simply means that the OS handle value may remain
// bound for the duration of the process.
if (_osfile(target_fh) & FOPEN)
{
_close_nolock(target_fh);
}
// Duplicate the source file onto the target file:
intptr_t new_osfhandle;
BOOL const result = DuplicateHandle(
GetCurrentProcess(),
reinterpret_cast<HANDLE>(_get_osfhandle(source_fh)),
GetCurrentProcess(),
&reinterpret_cast<HANDLE&>(new_osfhandle),
0,
TRUE,
DUPLICATE_SAME_ACCESS);
if (!result)
{
__acrt_errno_map_os_error(GetLastError());
return -1;
}
__acrt_lowio_set_os_handle(target_fh, new_osfhandle);
// Copy the _osfile information, with the FNOINHERIT bit cleared:
_osfile(target_fh) = _osfile(source_fh) & ~FNOINHERIT;
_textmode(target_fh) = _textmode(source_fh);
_tm_unicode(target_fh) = _tm_unicode(source_fh);
return 0;
}
static int __cdecl _dup_nolock(
int fh
)
{
int newfh; /* variable for new file handle */
ULONG dosretval; /* o.s. return value */
char fileinfo; /* _osfile info for file */
intptr_t new_osfhandle;
int success = FALSE;
fileinfo = _osfile(fh); /* get file info for file */
if ( !(_osfile(fh) & FOPEN) )
return -1;
/* create duplicate handle */
if ( (newfh = _alloc_osfhnd()) == -1 )
{
errno = EMFILE; /* too many files error */
_doserrno = 0L; /* not an OS error */
return -1; /* return error to caller */
}
__TRY
/*
* duplicate the file handle
*/
if ( !(DuplicateHandle(GetCurrentProcess(),
(HANDLE)_get_osfhandle(fh),
GetCurrentProcess(),
(PHANDLE)&new_osfhandle,
0L,
TRUE,
DUPLICATE_SAME_ACCESS)) )
{
dosretval = GetLastError();
}
else {
_set_osfhnd(newfh, new_osfhandle);
dosretval = 0;
}
if (dosretval)
{
/* o.s. error -- map errpr and release handle */
_dosmaperr(dosretval);
}
else
{
/*
* copy the _osfile value, with the FNOINHERIT bit cleared
*/
_osfile(newfh) = fileinfo & ~FNOINHERIT;
_textmode(newfh) = _textmode(fh);
_tm_unicode(newfh) = _tm_unicode(fh);
success = TRUE;
}
__FINALLY
if (!success)
{
_osfile(newfh) &= ~FOPEN;
}
_unlock_fh(newfh);
__END_TRY_FINALLY
return success ? newfh : -1;
}
static int __cdecl _dup2_nolock (
int fh1,
int fh2
)
{
ULONG dosretval; /* o.s. return code */
intptr_t new_osfhandle;
/*
* Re-test and take care of case of unopened source handle. This is
* necessary only in the multi-thread case where the file have been
* closed by another thread before the lock was asserted, but after
* the initial test above.
*/
if ( !(_osfile(fh1) & FOPEN) ) {
/*
* Source handle isn't open, bail out with an error.
* Note that the DuplicateHandle API will not detect this
* error since it implies that _osfhnd(fh1) ==
* INVALID_HANDLE_VALUE, and this is a legal HANDLE value
* (it's the HANDLE for the current process).
*/
errno = EBADF;
_doserrno = 0; /* not an OS error */
_ASSERTE(("Invalid file descriptor. File possibly closed by a different thread",0));
return -1;
}
/*
* Take of the case of equal handles.
*/
if ( fh1 == fh2 )
/*
* Since fh1 is known to be open, return 0 indicating success.
* This is in conformance with the POSIX specification for
* dup2.
*/
return 0;
/*
* if fh2 is open, close it.
*/
if ( _osfile(fh2) & FOPEN )
/*
* close the handle. ignore the possibility of an error - an
* error simply means that an OS handle value may remain bound
* for the duration of the process. Use _close_nolock as we
* already own lock
*/
(void) _close_nolock(fh2);
/* Duplicate source file onto target file */
if ( !(DuplicateHandle(GetCurrentProcess(),
(HANDLE)_get_osfhandle(fh1),
GetCurrentProcess(),
(PHANDLE)&new_osfhandle,
0L,
TRUE,
DUPLICATE_SAME_ACCESS)) )
{
dosretval = GetLastError();
}
else {
_set_osfhnd(fh2, new_osfhandle);
dosretval = 0;
}
if (dosretval) {
_dosmaperr(dosretval);
return -1;
}
/* copy the _osfile information, with the FNOINHERIT bit cleared */
_osfile(fh2) = _osfile(fh1) & ~FNOINHERIT;
_textmode(fh2) = _textmode(fh1);
_tm_unicode(fh2) = _tm_unicode(fh1);
return 0;
}
