536 lines
18 KiB
C
536 lines
18 KiB
C
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/***
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*open.c - file open
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*
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* Copyright (c) 1989-2001, Microsoft Corporation. All rights reserved.
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*
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*Purpose:
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* defines _open() and _sopen() - open or create a file
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*
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*Revision History:
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* 06-13-89 PHG Module created, based on asm version
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* 11-11-89 JCR Replaced DOS32QUERYFILEMODE with DOS32QUERYPATHINFO
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* 03-13-90 GJF Made calling type _CALLTYPE2 (for now), added #include
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* <cruntime.h>, fixed some compiler warnings and fixed
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* copyright. Also, cleaned up the formatting a bit.
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* 07-24-90 SBM Removed '32' from API names
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* 08-14-90 SBM Compiles cleanly with -W3
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* 09-07-90 SBM Added stdarg code (inside #if 0..#endif) to make
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* open and sopen match prototypes. Test and use this
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* someday.
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* 10-01-90 GJF New-style function declarators.
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* 11-16-90 GJF Wrote version for Win32 API and appended it via an
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* #ifdef. The Win32 version is similar to the old DOS
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* version (though in C) and far different from either
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* the Cruiser or OS/2 versions.
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* 12-03-90 GJF Fixed a dozen or so minor errors in the Win32 version.
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* 12-06-90 SRW Changed to use _osfile and _osfhnd instead of _osfinfo
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* 12-28-90 SRW Added cast of void * to char * for Mips C Compiler
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* 12-31-90 SRW Fixed spen to call CreateFile instead of OpenFile
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* 01-16-91 GJF ANSI naming.
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* 02-07-91 SRW Changed to call _get_osfhandle [_WIN32_]
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* 02-19-91 SRW Adapt to OpenFile/CreateFile changes [_WIN32_]
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* 02-25-91 SRW Renamed _get_free_osfhnd to be _alloc_osfhnd [_WIN32_]
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* 04-09-91 PNT Added _MAC_ conditional
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* 07-10-91 GJF Store fileflags into _osfile array before call to
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* _lseek_lk (bug found by LarryO) [_WIN32_].
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* 01-02-92 GJF Fixed Win32 version (not Cruiser!) so that pmode is not
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* referenced unless _O_CREAT has been specified.
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* 02-04-92 GJF Make better use of CreateFile options.
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* 04-06-92 SRW Pay attention to _O_NOINHERIT flag in oflag parameter
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* 05-02-92 SRW Add support for _O_TEMPORARY flag in oflag parameter.
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* Causes FILE_ATTRIBUTE_TEMPORARY flag to be set in call
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* to the Win32 CreateFile API.
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* 07-01-92 GJF Close handle in case of error. Also, don't try to set
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* FRDONLY bit anymore - no longer needed/used. [_WIN32_].
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* 01-03-93 SRW Fix va_arg/va_end usage
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* 04-06-93 SKS Replace _CRTAPI* with __cdecl
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* 05-24-93 PML Add support for _O_SEQUENTIAL, _O_RANDOM,
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* and _O_SHORT_LIVED
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* 07-12-93 GJF Fixed bug in reading last char in text file. Also,use
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* proper SEEK constants in _lseek_lk calls.
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* 11-01-93 CFW Enable Unicode variant, rip out CRUISER.
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* 02-15-95 GJF Appended Mac version of source file (somewhat cleaned
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* up), with appropriate #ifdef-s.
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* 06-06-95 CFW Enable shared writing.
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* 06-12-95 GJF Replaced _osfile[] with _osfile() (macro referencing
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* field in ioinfo struct).
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* 05-16-96 GJF Propagate _O_NOINHERIT to FNOINHERIT (new _osfile
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* bit). Also detab-ed.
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* 05-31-96 SKS Fix expression error in GJF's most recent check-in
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* 07-08-96 GJF Replaced defined(_WIN32) with !defined(_MAC), and
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* defined(_M_M68K) || defined(_M_MPPC) with
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* defined(_MAC). Also, cleaned up the format a bit.
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* 08-01-96 RDK For PMac, change data type for _endlowio terminator
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* pointer, use safer PBHOpenDFSync call, and process
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* _O_TEMPORARY open flag to implement delete after close.
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* 12-29-97 GJF Exception-safe locking.
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* 02-07-98 GJF Changes for Win64: arg type for _set_osfhnd is now
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* intptr_t.
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* 04-28-99 PML Wrap __declspec(allocate()) in _CRTALLOC macro.
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* 05-17-99 PML Remove all Macintosh support.
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* 10-27-99 GB VS7#14742 made a fix for opening the file in
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* O_TEMPORARY mode so as to enable sucessive open on the
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* same file if share permissions are there.
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*
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*******************************************************************************/
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#include <sect_attribs.h>
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#include <cruntime.h>
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#include <oscalls.h>
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#include <msdos.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <internal.h>
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#include <io.h>
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#include <share.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <sys\types.h>
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#include <sys\stat.h>
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#include <mtdll.h>
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#include <stdarg.h>
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#include <tchar.h>
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#ifdef _MT
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static int __cdecl _tsopen_lk ( int *,
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int *,
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const _TSCHAR *,
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int,
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int,
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int );
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#endif /* _MT */
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/***
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*int _open(path, flag, pmode) - open or create a file
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*
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*Purpose:
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* Opens the file and prepares for subsequent reading or writing.
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* the flag argument specifies how to open the file:
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* _O_APPEND - reposition file ptr to end before every write
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* _O_BINARY - open in binary mode
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* _O_CREAT - create a new file* no effect if file already exists
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* _O_EXCL - return error if file exists, only use with O_CREAT
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* _O_RDONLY - open for reading only
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* _O_RDWR - open for reading and writing
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* _O_TEXT - open in text mode
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* _O_TRUNC - open and truncate to 0 length (must have write permission)
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* _O_WRONLY - open for writing only
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* _O_NOINHERIT -handle will not be inherited by child processes.
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* exactly one of _O_RDONLY, _O_WRONLY, _O_RDWR must be given
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*
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* The pmode argument is only required when _O_CREAT is specified. Its
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* flag settings:
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* _S_IWRITE - writing permitted
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* _S_IREAD - reading permitted
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* _S_IREAD | _S_IWRITE - both reading and writing permitted
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* The current file-permission maks is applied to pmode before
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* setting the permission (see umask).
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*
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* The oflag and mode parameter have different meanings under DOS. See
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* the A_xxx attributes in msdos.inc
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*
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* Note, the _creat() function also uses this function but setting up the
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* correct arguments and calling _open(). _creat() sets the __creat_flag
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* to 1 prior to calling _open() so _open() can return correctly. _open()
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* returns the file handle in eax in this case.
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*
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*Entry:
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* _TSCHAR *path - file name
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* int flag - flags for _open()
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* int pmode - permission mode for new files
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*
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*Exit:
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* returns file handle of open file if successful
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* returns -1 (and sets errno) if fails
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*
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*Exceptions:
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*
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*******************************************************************************/
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int __cdecl _topen (
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const _TSCHAR *path,
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int oflag,
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...
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)
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{
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va_list ap;
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int pmode;
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#ifdef _MT
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int fh;
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int retval;
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int unlock_flag = 0;
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#endif /* MT */
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va_start(ap, oflag);
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pmode = va_arg(ap, int);
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va_end(ap);
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#ifdef _MT
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__try {
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retval = _tsopen_lk( &unlock_flag,
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&fh,
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path,
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oflag,
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_SH_DENYNO,
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pmode );
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}
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__finally {
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if ( unlock_flag )
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_unlock_fh(fh);
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}
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return retval;
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#else /* ndef _MT */
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/* default sharing mode is DENY NONE */
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return _tsopen(path, oflag, _SH_DENYNO, pmode);
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#endif /* _MT */
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}
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/***
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*int _sopen(path, oflag, shflag, pmode) - opne a file with sharing
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*
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*Purpose:
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* Opens the file with possible file sharing.
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* shflag defines the sharing flags:
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* _SH_COMPAT - set compatability mode
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* _SH_DENYRW - deny read and write access to the file
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* _SH_DENYWR - deny write access to the file
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* _SH_DENYRD - deny read access to the file
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* _SH_DENYNO - permit read and write access
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*
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* Other flags are the same as _open().
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*
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* SOPEN is the routine used when file sharing is desired.
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*
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*Entry:
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* _TSCHAR *path - file to open
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* int oflag - open flag
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* int shflag - sharing flag
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* int pmode - permission mode (needed only when creating file)
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*
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*Exit:
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* returns file handle for the opened file
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* returns -1 and sets errno if fails.
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*
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*Exceptions:
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*
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*******************************************************************************/
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int __cdecl _tsopen (
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const _TSCHAR *path,
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int oflag,
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int shflag,
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...
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)
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{
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#ifdef _MT
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va_list ap;
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int pmode;
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int fh;
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int retval;
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int unlock_flag = 0;
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va_start(ap, shflag);
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pmode = va_arg(ap, int);
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va_end(ap);
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__try {
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retval = _tsopen_lk( &unlock_flag,
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&fh,
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path,
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oflag,
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shflag,
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pmode );
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}
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__finally {
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if ( unlock_flag )
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_unlock_fh(fh);
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}
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return retval;
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}
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static int __cdecl _tsopen_lk (
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int *punlock_flag,
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int *pfh,
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const _TSCHAR *path,
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int oflag,
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int shflag,
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int pmode
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)
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{
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#endif /* _MT */
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int fh; /* handle of opened file */
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int filepos; /* length of file - 1 */
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_TSCHAR ch; /* character at end of file */
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char fileflags; /* _osfile flags */
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#ifndef _MT
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va_list ap;
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int pmode;
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#endif /* _MT */
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HANDLE osfh; /* OS handle of opened file */
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DWORD fileaccess; /* OS file access (requested) */
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DWORD fileshare; /* OS file sharing mode */
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DWORD filecreate; /* OS method of opening/creating */
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DWORD fileattrib; /* OS file attribute flags */
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DWORD isdev; /* device indicator in low byte */
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SECURITY_ATTRIBUTES SecurityAttributes;
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SecurityAttributes.nLength = sizeof( SecurityAttributes );
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SecurityAttributes.lpSecurityDescriptor = NULL;
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if (oflag & _O_NOINHERIT) {
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SecurityAttributes.bInheritHandle = FALSE;
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fileflags = FNOINHERIT;
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}
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else {
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SecurityAttributes.bInheritHandle = TRUE;
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fileflags = 0;
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}
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/* figure out binary/text mode */
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if ((oflag & _O_BINARY) == 0)
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if (oflag & _O_TEXT)
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fileflags |= FTEXT;
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else if (_fmode != _O_BINARY) /* check default mode */
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fileflags |= FTEXT;
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/*
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* decode the access flags
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*/
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switch( oflag & (_O_RDONLY | _O_WRONLY | _O_RDWR) ) {
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case _O_RDONLY: /* read access */
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fileaccess = GENERIC_READ;
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break;
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case _O_WRONLY: /* write access */
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fileaccess = GENERIC_WRITE;
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break;
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case _O_RDWR: /* read and write access */
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fileaccess = GENERIC_READ | GENERIC_WRITE;
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break;
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default: /* error, bad oflag */
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errno = EINVAL;
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_doserrno = 0L; /* not an OS error */
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return -1;
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}
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/*
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* decode sharing flags
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*/
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switch ( shflag ) {
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case _SH_DENYRW: /* exclusive access */
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fileshare = 0L;
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break;
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case _SH_DENYWR: /* share read access */
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fileshare = FILE_SHARE_READ;
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break;
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case _SH_DENYRD: /* share write access */
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fileshare = FILE_SHARE_WRITE;
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break;
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case _SH_DENYNO: /* share read and write access */
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fileshare = FILE_SHARE_READ | FILE_SHARE_WRITE;
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break;
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default: /* error, bad shflag */
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errno = EINVAL;
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_doserrno = 0L; /* not an OS error */
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return -1;
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}
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/*
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* decode open/create method flags
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*/
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switch ( oflag & (_O_CREAT | _O_EXCL | _O_TRUNC) ) {
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case 0:
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case _O_EXCL: // ignore EXCL w/o CREAT
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filecreate = OPEN_EXISTING;
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break;
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case _O_CREAT:
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filecreate = OPEN_ALWAYS;
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break;
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case _O_CREAT | _O_EXCL:
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case _O_CREAT | _O_TRUNC | _O_EXCL:
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filecreate = CREATE_NEW;
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break;
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case _O_TRUNC:
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||
|
|
case _O_TRUNC | _O_EXCL: // ignore EXCL w/o CREAT
|
||
|
|
filecreate = TRUNCATE_EXISTING;
|
||
|
|
break;
|
||
|
|
|
||
|
|
case _O_CREAT | _O_TRUNC:
|
||
|
|
filecreate = CREATE_ALWAYS;
|
||
|
|
break;
|
||
|
|
|
||
|
|
default:
|
||
|
|
// this can't happen ... all cases are covered
|
||
|
|
errno = EINVAL;
|
||
|
|
_doserrno = 0L;
|
||
|
|
return -1;
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* decode file attribute flags if _O_CREAT was specified
|
||
|
|
*/
|
||
|
|
fileattrib = FILE_ATTRIBUTE_NORMAL; /* default */
|
||
|
|
|
||
|
|
if ( oflag & _O_CREAT ) {
|
||
|
|
#ifndef _MT
|
||
|
|
/*
|
||
|
|
* set up variable argument list stuff
|
||
|
|
*/
|
||
|
|
va_start(ap, shflag);
|
||
|
|
pmode = va_arg(ap, int);
|
||
|
|
va_end(ap);
|
||
|
|
#endif /* _MT */
|
||
|
|
|
||
|
|
if ( !((pmode & ~_umaskval) & _S_IWRITE) )
|
||
|
|
fileattrib = FILE_ATTRIBUTE_READONLY;
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Set temporary file (delete-on-close) attribute if requested.
|
||
|
|
*/
|
||
|
|
if ( oflag & _O_TEMPORARY ) {
|
||
|
|
fileattrib |= FILE_FLAG_DELETE_ON_CLOSE;
|
||
|
|
fileaccess |= DELETE;
|
||
|
|
if (_osplatform == VER_PLATFORM_WIN32_NT )
|
||
|
|
fileshare |= FILE_SHARE_DELETE;
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Set temporary file (delay-flush-to-disk) attribute if requested.
|
||
|
|
*/
|
||
|
|
if ( oflag & _O_SHORT_LIVED )
|
||
|
|
fileattrib |= FILE_ATTRIBUTE_TEMPORARY;
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Set sequential or random access attribute if requested.
|
||
|
|
*/
|
||
|
|
if ( oflag & _O_SEQUENTIAL )
|
||
|
|
fileattrib |= FILE_FLAG_SEQUENTIAL_SCAN;
|
||
|
|
else if ( oflag & _O_RANDOM )
|
||
|
|
fileattrib |= FILE_FLAG_RANDOM_ACCESS;
|
||
|
|
|
||
|
|
/*
|
||
|
|
* get an available handle.
|
||
|
|
*
|
||
|
|
* multi-thread note: the returned handle is locked!
|
||
|
|
*/
|
||
|
|
if ( (fh = _alloc_osfhnd()) == -1 ) {
|
||
|
|
errno = EMFILE; /* too many open files */
|
||
|
|
_doserrno = 0L; /* not an OS error */
|
||
|
|
return -1; /* return error to caller */
|
||
|
|
}
|
||
|
|
|
||
|
|
#ifdef _MT
|
||
|
|
*punlock_flag = 1;
|
||
|
|
*pfh = fh;
|
||
|
|
#endif
|
||
|
|
|
||
|
|
/*
|
||
|
|
* try to open/create the file
|
||
|
|
*/
|
||
|
|
if ( (osfh = CreateFile( (LPTSTR)path,
|
||
|
|
fileaccess,
|
||
|
|
fileshare,
|
||
|
|
&SecurityAttributes,
|
||
|
|
filecreate,
|
||
|
|
fileattrib,
|
||
|
|
NULL ))
|
||
|
|
== (HANDLE)(-1) )
|
||
|
|
{
|
||
|
|
/*
|
||
|
|
* OS call to open/create file failed! map the error, release
|
||
|
|
* the lock, and return -1. note that it's not necessary to
|
||
|
|
* call _free_osfhnd (it hasn't been used yet).
|
||
|
|
*/
|
||
|
|
_dosmaperr(GetLastError()); /* map error */
|
||
|
|
return -1; /* return error to caller */
|
||
|
|
}
|
||
|
|
|
||
|
|
/* find out what type of file (file/device/pipe) */
|
||
|
|
if ( (isdev = GetFileType(osfh)) == FILE_TYPE_UNKNOWN ) {
|
||
|
|
CloseHandle(osfh);
|
||
|
|
_dosmaperr(GetLastError()); /* map error */
|
||
|
|
return -1;
|
||
|
|
}
|
||
|
|
|
||
|
|
/* is isdev value to set flags */
|
||
|
|
if (isdev == FILE_TYPE_CHAR)
|
||
|
|
fileflags |= FDEV;
|
||
|
|
else if (isdev == FILE_TYPE_PIPE)
|
||
|
|
fileflags |= FPIPE;
|
||
|
|
|
||
|
|
/*
|
||
|
|
* the file is open. now, set the info in _osfhnd array
|
||
|
|
*/
|
||
|
|
_set_osfhnd(fh, (intptr_t)osfh);
|
||
|
|
|
||
|
|
/*
|
||
|
|
* mark the handle as open. store flags gathered so far in _osfile
|
||
|
|
* array.
|
||
|
|
*/
|
||
|
|
fileflags |= FOPEN;
|
||
|
|
_osfile(fh) = fileflags;
|
||
|
|
|
||
|
|
if ( !(fileflags & (FDEV|FPIPE)) && (fileflags & FTEXT) &&
|
||
|
|
(oflag & _O_RDWR) )
|
||
|
|
{
|
||
|
|
/* We have a text mode file. If it ends in CTRL-Z, we wish to
|
||
|
|
remove the CTRL-Z character, so that appending will work.
|
||
|
|
We do this by seeking to the end of file, reading the last
|
||
|
|
byte, and shortening the file if it is a CTRL-Z. */
|
||
|
|
|
||
|
|
if ((filepos = _lseek_lk(fh, -1, SEEK_END)) == -1) {
|
||
|
|
/* OS error -- should ignore negative seek error,
|
||
|
|
since that means we had a zero-length file. */
|
||
|
|
if (_doserrno != ERROR_NEGATIVE_SEEK) {
|
||
|
|
_close_lk(fh);
|
||
|
|
return -1;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
else {
|
||
|
|
/* Seek was OK, read the last char in file. The last
|
||
|
|
char is a CTRL-Z if and only if _read returns 0
|
||
|
|
and ch ends up with a CTRL-Z. */
|
||
|
|
ch = 0;
|
||
|
|
if (_read_lk(fh, &ch, 1) == 0 && ch == 26) {
|
||
|
|
/* read was OK and we got CTRL-Z! Wipe it
|
||
|
|
out! */
|
||
|
|
if (_chsize_lk(fh,filepos) == -1)
|
||
|
|
{
|
||
|
|
_close_lk(fh);
|
||
|
|
return -1;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
/* now rewind the file to the beginning */
|
||
|
|
if ((filepos = _lseek_lk(fh, 0, SEEK_SET)) == -1) {
|
||
|
|
_close_lk(fh);
|
||
|
|
return -1;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Set FAPPEND flag if appropriate. Don't do this for devices or pipes.
|
||
|
|
*/
|
||
|
|
if ( !(fileflags & (FDEV|FPIPE)) && (oflag & _O_APPEND) )
|
||
|
|
_osfile(fh) |= FAPPEND;
|
||
|
|
|
||
|
|
return fh; /* return handle */
|
||
|
|
}
|