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590 lines
16 KiB
590 lines
16 KiB
/***
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*open.c - file open
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*
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* Copyright (c) 1989-1993, 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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* 05-24-93 PML Add support for _O_SEQUENTIAL, _O_RANDOM,
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* and _O_SHORT_LIVED
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*
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*******************************************************************************/
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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 <stdlib.h>
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#include <sys\types.h>
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#include <sys\stat.h>
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#include <os2dll.h>
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#include <stdarg.h>
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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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* char *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 _CRTAPI2 _open (
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const char *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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va_start(ap, oflag);
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pmode = va_arg(ap, int);
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va_end(ap);
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/* default sharing mode is DENY NONE */
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return _sopen(path, oflag, _SH_DENYNO, pmode);
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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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* char *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 _CRTAPI2 _sopen (
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const char *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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int fh; /* handle of opened file */
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int filepos; /* length of file - 1 */
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char ch; /* character at end of file */
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char fileflags; /* _osfile flags */
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va_list ap; /* variable argument (pmode) */
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int pmode;
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#ifdef _CRUISER_
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int t; /* temp */
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int dosretval; /* OS/2 return value */
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int isdev; /* device indicator in low byte */
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int attrib; /* attribute */
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int openflag; /* OS/2 open flag */
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int openmode; /* OS/2 open mode */
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#endif /* _CRUISER_ */
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#ifdef _WIN32_
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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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}
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else {
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SecurityAttributes.bInheritHandle = TRUE;
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}
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#endif /* _WIN32_ */
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#ifdef _CRUISER_
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/* Set up variable argument list stuff */
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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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#endif
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/* figure out binary/text mode */
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if (oflag & _O_BINARY)
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fileflags = 0;
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else if (oflag & _O_TEXT)
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fileflags = (char)FTEXT;
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else if (_fmode == _O_BINARY) /* check default mode */
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fileflags = 0;
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else
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fileflags = (char)FTEXT;
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#ifdef _CRUISER_ /* CRUISER TARGET */
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/* code requires below conditions */
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#if _O_RDONLY != OPEN_ACCESS_READONLY || _O_WRONLY != OPEN_ACCESS_WRITEONLY || _O_RDWR != OPEN_ACCESS_READWRITE
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#error OS/2 and XENIX flags not compatible
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#endif
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#if _O_RDWR != 2 || _O_RDONLY != 0 || _O_WRONLY != 1
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#error access flags are wrong
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#endif
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/*
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Set up the OpenMode and OpenFlag parameters for the DOSOPEN call
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OpenMode fields will be set as follows:
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high byte
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DASD 0 (normal file)
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File Write-through 0 (use buffer cache)
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Fail-Errors 0 (use hard error handler)
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low byte
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Inheritance 0 (child inherits files)
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Sharing Mode <from shflag param>
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Access Mode <from oflag parameter>
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OpenFlag bytes are set as follows:
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high byte
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0x00
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low byte - low nibble
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0x0 _O_EXCL specified
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0x2 _O_TRUNC specified
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0x1 otherwise
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low byte - high nibble
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0x1 _O_CREAT specified
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0x0 otherwise
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*/
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/* first, convert the permission mode to the DOS attribute byte */
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if ((pmode & ~_umaskval) & _S_IWRITE)
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attrib = 0; /* writable */
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else
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attrib = FILE_READONLY; /* read-only */
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if ((oflag & _O_EXCL) && !(oflag & _O_CREAT))
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oflag &= ~_O_EXCL; /* _O_EXCL only works with _O_CREAT */
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if (oflag & _O_EXCL) {
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openflag = 0; /* just create */
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}
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else if (oflag & _O_TRUNC) {
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FILESTATUS fs; /* File Status structure */
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openflag = FILE_TRUNCATE; /* truncate file */
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/* if the file exists, don't change its attribute */
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if (!DOSQUERYPATHINFO((char *)path, 1, &fs, sizeof(fs)))
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/* file exists, use current attribute */
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attrib = fs.attrFile;
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}
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else
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openflag = FILE_OPEN; /* open the file */
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if (oflag & _O_CREAT)
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openflag |= FILE_CREATE;
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/* here we take advantage of the fact that OS/2 and XENIX access flags
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are the same bits -- the bottom two */
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openmode = shflag | (oflag & 3);
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/* OK, we're now ready to open the file */
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if (dosretval = DOSOPEN((char *)path, &fh, &t, 0, attrib, openflag,
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openmode, 0, 0)) {
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/* OS/2 error occured */
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if (dosretval == ERROR_OPEN_FAILED) {
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_doserrno = dosretval;
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if (openflag & FILE_CREATE)
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errno = EEXIST; /* file existed */
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else
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errno = ENOENT; /* file didn't exist */
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return -1;
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}
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else {
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_dosmaperr(dosretval); /* map error */
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return -1;
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}
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}
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if ((unsigned)fh >= (unsigned)_nfile) {
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/* handle is out of range; close and return EMFILE */
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DOSCLOSE(fh);
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errno = EMFILE;
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_doserrno = 0; /* not OS/2 error */
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return -1;
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}
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_lock_fh(fh); /* lock the file handle */
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/* find out what type of file (file/device/pipe) */
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if (dosretval = DOSQUERYHTYPE(fh, &isdev, &t)) {
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/* OS/2 error */
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_unlock_fh(fh);
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_dosmaperr(dosretval); /* map error */
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return -1;
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}
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/* is isdev value to set flags */
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if ((isdev & 0xFF) == HANDTYPE_DEVICE)
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fileflags |= FDEV;
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else if ((isdev & 0xFF) == HANDTYPE_PIPE)
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fileflags |= FPIPE;
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#else /* ndef _CRUISER_ */
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#ifdef _WIN32_
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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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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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filecreate = CREATE_NEW;
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break;
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case _O_TRUNC:
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filecreate = TRUNCATE_EXISTING;
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break;
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case _O_CREAT | _O_TRUNC:
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filecreate = CREATE_ALWAYS;
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break;
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default:
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errno = EINVAL;
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_doserrno = 0L;
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return -1;
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}
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/*
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* decode file attribute flags if _O_CREAT was specified
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*/
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fileattrib = FILE_ATTRIBUTE_NORMAL; /* default */
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if ( oflag & _O_CREAT ) {
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/*
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* set up variable argument list stuff
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*/
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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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if ( !((pmode & ~_umaskval) & _S_IWRITE) )
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fileattrib = FILE_ATTRIBUTE_READONLY;
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}
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/*
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* Set temporary file (delete-on-close) attribute if requested.
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*/
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if ( oflag & _O_TEMPORARY ) {
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fileattrib |= FILE_FLAG_DELETE_ON_CLOSE;
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fileaccess |= DELETE;
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}
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/*
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* Set temporary file (delay-flush-to-disk) attribute if requested.
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*/
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if ( oflag & _O_SHORT_LIVED )
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fileattrib |= FILE_ATTRIBUTE_TEMPORARY;
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/*
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* Set sequential or random access attribute if requested.
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*/
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if ( oflag & _O_SEQUENTIAL )
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fileattrib |= FILE_FLAG_SEQUENTIAL_SCAN;
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else if ( oflag & _O_RANDOM )
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fileattrib |= FILE_FLAG_RANDOM_ACCESS;
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/*
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* get an available handle.
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*
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* multi-thread note: the returned handle is locked!
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*/
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if ( (fh = _alloc_osfhnd()) == -1 ) {
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errno = EMFILE; /* too many open files */
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_doserrno = 0L; /* not an OS error */
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return -1; /* return error to caller */
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}
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/*
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* try to open/create the file
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*/
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if ( (osfh = CreateFile((LPSTR)path,
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fileaccess,
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fileshare,
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&SecurityAttributes,
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filecreate,
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fileattrib,
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NULL
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))
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== (HANDLE)0xffffffff ) {
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/*
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* OS call to open/create file failed! map the error, release
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* the lock, and return -1. note that it's not necessary to
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* call _free_osfhnd (it hasn't been used yet).
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*/
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_dosmaperr(GetLastError()); /* map error */
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_unlock_fh(fh);
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return -1; /* return error to caller */
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}
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/* find out what type of file (file/device/pipe) */
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if ( (isdev = GetFileType(osfh)) == FILE_TYPE_UNKNOWN ) {
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CloseHandle(osfh);
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_dosmaperr(GetLastError()); /* map error */
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_unlock_fh(fh);
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return -1;
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}
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/* is isdev value to set flags */
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if (isdev == FILE_TYPE_CHAR)
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fileflags |= FDEV;
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else if (isdev == FILE_TYPE_PIPE)
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fileflags |= FPIPE;
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/*
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* the file is open. now, set the info in _osfhnd array
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*/
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_set_osfhnd(fh, (long)osfh);
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#else /* ndef _WIN32_ */
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#ifdef _MAC_
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TBD();
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#else /* ndef _MAC_ */
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#error ERROR - ONLY CRUISER, WIN32, OR MAC TARGET SUPPORTED!
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#endif /* _MAC_ */
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#endif /* _WIN32_ */
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#endif /* _CRUISER_ */
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/*
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* mark the handle as open. store flags gathered so far in _osfile
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* array.
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*/
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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, FILE_END)) == -1) {
|
|
/* OS error -- should ignore negative seek error,
|
|
since that means we had a zero-length file. */
|
|
if (_doserrno != ERROR_NEGATIVE_SEEK) {
|
|
_close(fh);
|
|
_unlock_fh(fh);
|
|
return -1;
|
|
}
|
|
}
|
|
else {
|
|
/* seek was OK, read the last char in file */
|
|
if (_read_lk(fh, &ch, 1) == 1 && ch == 26) {
|
|
/* read was OK and we got CTRL-Z! Wipe it
|
|
out! */
|
|
if (_chsize_lk(fh,filepos) == -1)
|
|
{
|
|
_close(fh);
|
|
_unlock_fh(fh);
|
|
return -1;
|
|
}
|
|
}
|
|
|
|
/* now rewind the file to the beginning */
|
|
if ((filepos = _lseek_lk(fh, 0, FILE_BEGIN)) == -1) {
|
|
_close(fh);
|
|
_unlock_fh(fh);
|
|
return -1;
|
|
}
|
|
}
|
|
}
|
|
|
|
#ifdef _CRUISER_
|
|
/* We want to know if we have write access to set the FRDONLY flag
|
|
in the _osfile entry. We also set the FAPPEND flag.
|
|
Don't do this for pipes or devices. */
|
|
|
|
if (!(fileflags & (FDEV|FPIPE))) {
|
|
if (_access((char *)path, 2) == -1)
|
|
_osfile[fh] |= FRDONLY;
|
|
|
|
if (oflag & _O_APPEND)
|
|
_osfile[fh] |= FAPPEND;
|
|
}
|
|
#else /* ndef _CRUISER_ */
|
|
#ifdef _WIN32_
|
|
|
|
/*
|
|
* Set FAPPEND flag if appropriate. Don't do this for devices or pipes.
|
|
*/
|
|
if ( !(fileflags & (FDEV|FPIPE)) && (oflag & _O_APPEND) )
|
|
_osfile[fh] |= FAPPEND;
|
|
|
|
#endif /* _WIN32_ */
|
|
#endif /* _CRUISER_*/
|
|
|
|
_unlock_fh(fh); /* unlock handle */
|
|
|
|
return fh; /* return handle */
|
|
}
|