145 lines
4.8 KiB
C
145 lines
4.8 KiB
C
/***
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*pipe.c - create a pipe
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*
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* Copyright (c) 1989-1995, Microsoft Corporation. All rights reserved.
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*
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*Purpose:
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* defines _pipe() - creates a pipe (i.e., an I/O channel for interprocess
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* communication)
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*
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*Revision History:
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* 06-20-89 PHG Module created, based on asm version
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* 03-13-90 GJF Made calling type _CALLTYPE2 (for now), added #include
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* <cruntime.h> and fixed copyright. Also, cleaned up the
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* formatting a bit.
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* 04-03-90 GJF Now _CALLTYPE1.
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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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* 10-01-90 GJF New-style function declarator.
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* 12-04-90 SRW Changed to include <oscalls.h> instead of <doscalls.h>
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* 12-06-90 SRW Added _CRUISER_ and _WIN32 conditionals.
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* 01-18-91 GJF ANSI naming.
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* 02-18-91 SRW Added _WIN32_ implementation [_WIN32_]
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* 02-25-91 SRW Renamed _get_free_osfhnd to be _alloc_osfhnd [_WIN32_]
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* 03-13-91 SRW Fixed _pipe so it works [_WIN32_]
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* 03-18-91 SRW Fixed _pipe NtCreatePipe handles are inherited [_WIN32_]
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* 04-06-92 SRW Pay attention to _O_NOINHERIT flag in oflag parameter
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* 01-10-93 GJF Fixed bug in checking for _O_BINARY (inadvertently
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* introduced by SRW's change above).
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* 04-06-93 SKS Replace _CRTAPI* with __cdecl
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* 09-06-94 CFW Remove Cruiser support.
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* 12-03-94 SKS Clean up OS/2 references
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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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*
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*******************************************************************************/
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#include <cruntime.h>
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#include <oscalls.h>
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#include <mtdll.h>
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#include <io.h>
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#include <internal.h>
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#include <stdlib.h>
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#include <errno.h>
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#include <msdos.h>
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#include <fcntl.h>
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/***
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*int _pipe(phandles, psize, textmode) - open a pipe
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*
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*Purpose:
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* Checks if the given handle is associated with a character device
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* (terminal, console, printer, serial port)
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*
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* Multi-thread notes: No locking is performed or deemed necessary. The
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* handles returned by DOSCREATEPIPE are newly opened and, therefore,
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* should not be referenced by any thread until after the _pipe call is
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* complete. The function is not protected from some thread of the caller
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* doing, say, output to a previously invalid handle that becomes one of
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* the pipe handles. However, any such program is doomed anyway and
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* protecting the _pipe function such a case would be of little value.
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*
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*Entry:
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* int phandle[2] - array to hold returned read (phandle[0]) and write
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* (phandle[1]) handles
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*
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* unsigned psize - amount of memory, in bytes, to ask o.s. to reserve
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* for the pipe
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*
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* int textmode - _O_TEXT, _O_BINARY, _O_NOINHERIT, or 0 (use default)
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*
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*Exit:
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* returns 0 if successful
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* returns -1 if an error occurs in which case, errno is set to:
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*
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*Exceptions:
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*
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*******************************************************************************/
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int __cdecl _pipe (
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int phandles[2],
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unsigned psize,
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int textmode
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)
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{
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ULONG dosretval; /* o.s. return value */
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HANDLE ReadHandle, WriteHandle;
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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 (textmode & _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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if (!CreatePipe(&ReadHandle, &WriteHandle, &SecurityAttributes, psize)) {
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/* o.s. error */
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dosretval = GetLastError();
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_dosmaperr(dosretval);
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return -1;
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}
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/* now we must allocate C Runtime handles for Read and Write handles */
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if ((phandles[0] = _alloc_osfhnd()) != -1) {
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_osfile(phandles[0]) = (char)(FOPEN | FPIPE | FTEXT);
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if ((phandles[1] = _alloc_osfhnd()) != -1) {
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_osfile(phandles[1]) = (char)(FOPEN | FPIPE | FTEXT);
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if ( (textmode & _O_BINARY) ||
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((textmode & _O_TEXT == 0) &&
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(_fmode == _O_BINARY)) ) {
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/* binary mode */
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_osfile(phandles[0]) &= ~FTEXT;
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_osfile(phandles[1]) &= ~FTEXT;
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}
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_set_osfhnd(phandles[0], (long)ReadHandle);
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_set_osfhnd(phandles[1], (long)WriteHandle);
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errno = 0;
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_unlock_fh(phandles[1]); /* unlock handle */
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}
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else {
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_osfile(phandles[0]) = 0;
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errno = EMFILE; /* too many files */
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}
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_unlock_fh(phandles[0]); /* unlock handle */
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}
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else {
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errno = EMFILE; /* too many files */
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}
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/* If error occurred, close Win32 handles and return -1 */
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if (errno != 0) {
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CloseHandle(ReadHandle);
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CloseHandle(WriteHandle);
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_doserrno = 0; /* not an o.s. error */
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return -1;
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}
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return 0;
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}
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