/***
*dup2.c - Duplicate file handles
*
* Copyright (c) 1989-1995, Microsoft Corporation. All rights reserved.
*
*Purpose:
* defines _dup2() - duplicate file handles
*
*Revision History:
* 06-09-89 PHG Module created, based on asm version
* 03-12-90 GJF Made calling type _CALLTYPE2 (for now), added #include
* <cruntime.h> and fixed the copyright. Also, cleaned up
* the formatting a bit.
* 04-03-90 GJF Now _CALLTYPE1.
* 07-24-90 SBM Removed '32' from API names
* 08-14-90 SBM Compiles cleanly with -W3
* 09-28-90 GJF New-style function declarator.
* 12-04-90 GJF Appended Win32 version onto the source with #ifdef-s.
* It is enough different that there is little point in
* trying to more closely merge the two versions.
* 12-04-90 SRW Changed to include <oscalls.h> instead of <doscalls.h>
* 12-06-90 SRW Changed to use _osfile and _osfhnd instead of _osfinfo
* 01-16-91 GJF ANSI naming.
* 02-07-91 SRW Changed to call _get_osfhandle [_WIN32_]
* 02-18-91 SRW Changed to call _free_osfhnd [_WIN32_]
* 02-25-91 SRW Renamed _get_free_osfhnd to be _alloc_osfhnd [_WIN32_]
* 02-13-92 GJF Replaced _nfile by _nhandle for Win32.
* 09-04-92 GJF Check for unopened fh1 and gracefully handle fh1 ==
* fh2.
* 04-06-93 SKS Replace _CRTAPI* with __cdecl
* 09-06-94 CFW Remove Cruiser support.
* 09-06-94 CFW Replace MTHREAD with _MT.
* 12-03-94 SKS Clean up OS/2 references
* 01-04-95 GJF _WIN32_ -> _WIN32
* 02-15-95 GJF Appended Mac version of source file (somewhat cleaned
* up), with appropriate #ifdef-s.
* 06-11-95 GJF Replaced _osfile[] with _osfile() (macro referencing
* field in ioinfo struct).
* 06-26-95 GJF Added support to grow the ioinfo arrays in order to
* ensure an ioinfo struct exists for fh2.
*
*******************************************************************************/
#ifdef _WIN32
#include <cruntime.h>
#include <io.h>
#include <oscalls.h>
#include <msdos.h>
#include <mtdll.h>
#include <errno.h>
#include <stdlib.h>
#include <internal.h>
#include <malloc.h>
#include <dbgint.h>
static int __cdecl extend_ioinfo_arrays(int);
/***
*int _dup2(fh1, fh2) - force handle 2 to refer to handle 1
*
*Purpose:
* Forces file handle 2 to refer to the same file as file
* handle 1. If file handle 2 referred to an open file, that file
* is closed.
*
* Multi-thread: We must hold 2 lowio locks at the same time
* to ensure multi-thread integrity. In order to prevent deadlock,
* we always get the lower file handle lock first. Order of unlocking
* does not matter. If you modify this routine, make sure you don't
* cause any deadlocks! Scary stuff, kids!!
*
*Entry:
* int fh1 - file handle to duplicate
* int fh2 - file handle to assign to file handle 1
*
*Exit:
* returns 0 if successful, -1 (and sets errno) if fails.
*
*Exceptions:
*
*******************************************************************************/
int __cdecl _dup2 (
int fh1,
int fh2
)
{
ULONG dosretval; /* o.s. return code */
/* validate file handles */
if ( ((unsigned)fh1 >= (unsigned)_nhandle) ||
!(_osfile(fh1) & FOPEN) ||
((unsigned)fh2 >= _NHANDLE_) ) {
/* handle out of range */
errno = EBADF;
_doserrno = 0; /* not an OS error */
return -1;
}
/*
* Make sure there is an ioinfo struct corresponding to fh2.
*/
if ( (fh2 >= _nhandle) && (extend_ioinfo_arrays(fh2) != 0) ) {
errno = ENOMEM;
return -1;
}
#if defined(_MT) && !defined(DLL_FOR_WIN32S)
/* get the two file handle locks; in order to prevent deadlock,
get the lowest handle lock first. */
if ( fh1 < fh2 ) {
_lock_fh(fh1);
_lock_fh(fh2);
}
else if ( fh1 > fh2 ) {
_lock_fh(fh2);
_lock_fh(fh1);
}
/*
* 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, release locks and 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).
*/
_unlock_fh(fh1);
_unlock_fh(fh2);
errno = EBADF;
_doserrno = 0; /* not an OS error */
return -1;
}
#endif
/*
* 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.
*/
_unlock_fh(fh1);
_unlock_fh(fh2);
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_lk as we
* already own lock
*/
(void) _close_lk(fh2);
/* Duplicate source file onto target file */
{
long new_osfhandle;
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);
_unlock_fh(fh1);
_unlock_fh(fh2);
return -1;
}
/* copy _osfile information */
_osfile(fh2) = _osfile(fh1);
/* unlock file handles */
_unlock_fh(fh1);
_unlock_fh(fh2);
return 0;
}
/***
*static int extend_ioinfo_arrays( int fh ) - extend ioinfo arrays to fh
*
*Purpose:
* Allocate and initialize arrays of ioinfo structs,filling in
* __pioinfo[],until there is an ioinfo struct corresponding to fh.
*
* Note: It is assumed the fh < _NHANDLE_!
*
*Entry:
* int fh - C file handle corresponding to ioinfo
*
*Exit:
* returns 0 if successful, -1
*
*Exceptions:
*
*******************************************************************************/
static int __cdecl extend_ioinfo_arrays(
int fh
)
{
ioinfo *pio;
int i;
/*
* Walk __pioinfo[], allocating an array of ioinfo structs for each
* empty entry, until there is an ioinfo struct corresponding to fh.
*/
for ( i = 0 ; fh >= _nhandle ; i++ ) {
if ( __pioinfo[i] == NULL ) {
if ( (pio = _malloc_crt( IOINFO_ARRAY_ELTS * sizeof(ioinfo) ))
!= NULL )
{
__pioinfo[i] = pio;
_nhandle += IOINFO_ARRAY_ELTS;
for ( ; pio < __pioinfo[i] + IOINFO_ARRAY_ELTS ; pio++ ) {
pio->osfile = 0;
pio->osfhnd = (long)INVALID_HANDLE_VALUE;
pio->pipech = 10;
#if defined(_MT) && !defined(DLL_FOR_WIN32S)
pio->lockinitflag = 0;
#endif
}
}
else {
/*
* Couldn't allocate another array, return failure.
*/
return -1;
}
}
}
return 0;
}
#else /* ndef _WIN32 */
#if defined(_M_MPPC) || defined(_M_M68K)
#include <cruntime.h>
#include <errno.h>
#include <io.h>
#include <internal.h>
#include <stdlib.h>
#include <msdos.h>
/***
*int _dup2(fh1, fh2) - force handle 2 to refer to handle 1
*
*Purpose:
* Forces file handle 2 to refer to the same file as file
* handle 1. If file handle 2 referred to an open file, that file
* is closed.
*
*
*Entry:
* int fh1 - file handle to duplicate
* int fh2 - file handle to assign to file handle 1
*
*Exit:
* returns 0 if successful, -1 (and sets errno) if fails.
*
*Exceptions:
*
*******************************************************************************/
int __cdecl _dup2 (
int fh1,
int fh2
)
{
if ((unsigned int)fh2 > (unsigned int)_nfile)
{
errno = EBADF;
_macerrno = 0;
return -1;
}
if (_osfile[fh2] & FOPEN)
{
_close(fh2);
}
if (__dupx(fh1, fh2) == fh2)
{
return 0;
}
else
{
return -1;
}
}
#endif /* defined(_M_MPPC) || defined(_M_M68K) */
#endif /* _WIN32 */