newlib/winsup/cygwin/fhandler_fifo.cc

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/* fhandler_fifo.cc. See fhandler.h for a description of the fhandler classes.
Copyright 2002, 2003 Red Hat, Inc.
This file is part of Cygwin.
This software is a copyrighted work licensed under the terms of the
Cygwin license. Please consult the file "CYGWIN_LICENSE" for
details. */
#include "winsup.h"
#include <errno.h>
#include <unistd.h>
#include <stdlib.h>
#include "cygerrno.h"
#include "perprocess.h"
#include "security.h"
#include "path.h"
#include "fhandler.h"
#include "dtable.h"
#include "cygheap.h"
#include "pinfo.h"
fhandler_fifo::fhandler_fifo ()
: fhandler_pipe (), output_handle (NULL), owner (NULL), upand (0),
read_use (0), write_use (0)
{
}
void
fhandler_fifo::set_use (int incr)
{
long oread_use = read_use;
if (get_flags () & (O_WRONLY | O_APPEND))
write_use += incr;
else if (get_flags () & O_RDWR)
{
write_use += incr;
read_use += incr;
}
else
read_use += incr;
if (incr >= 0)
return;
char buf[24];
__small_sprintf (buf, "%x.%x", upand, myself->pid);
ATOM ant = GlobalFindAtom (buf);
if (!ant)
return;
if (read_use <= 0 && oread_use != read_use)
{
HANDLE h = get_handle ();
if (h)
{
set_io_handle (NULL);
CloseHandle (h);
}
DeleteAtom (ant);
}
}
int
fhandler_fifo::close ()
{
fhandler_pipe::close ();
CloseHandle (get_output_handle ());
set_use (-1);
return 0;
}
#define DUMMY_O_RDONLY 4
int
fhandler_fifo::open_not_mine (int flags)
{
char buf[24];
winpids pids;
static int flagtypes[] = {DUMMY_O_RDONLY | O_RDWR, O_WRONLY | O_APPEND | O_RDWR};
HANDLE *usehandles[2] = {&(get_handle ()), &(get_output_handle ())};
int res;
for (unsigned i = 0; i < pids.npids; i++)
{
_pinfo *p = pids[i];
__small_sprintf (buf, "%x.%x", upand, p->pid);
if (!GlobalFindAtom (buf))
continue;
HANDLE hp = OpenProcess (PROCESS_DUP_HANDLE, false, p->dwProcessId);
if (!hp)
{
__seterrno ();
goto err;
}
HANDLE handles[2];
commune_result r;
r = p->commune_send (PICOM_FIFO, upand);
flags = (flags & (O_RDWR | O_WRONLY | O_APPEND)) ?: DUMMY_O_RDONLY;
for (int i = 0; i < 2; i++)
{
if (!(flags & flagtypes[i]))
continue;
if (!DuplicateHandle (hp, r.handles[i], hMainProc, usehandles[i], 0,
false, DUPLICATE_SAME_ACCESS))
{
debug_printf ("couldn't duplicate handle %d/%p, %E", i, handles[i]);
__seterrno ();
goto err;
}
if (i == 0)
{
read_state = CreateEvent (&sec_none_nih, FALSE, FALSE, NULL);
set_need_fork_fixup ();
}
}
CloseHandle (hp);
res = 1;
set_flags (flags);
goto out;
}
set_errno (EAGAIN);
err:
res = 0;
debug_printf ("failed");
out:
debug_printf ("res %d", res);
return res;
}
int
fhandler_fifo::open (int flags, mode_t)
{
int res = 1;
char buf[24];
upand = GlobalAddAtom (pc);
__small_sprintf (buf, "%x.owner", upand);
debug_printf ("mutex %s", buf);
HANDLE h = CreateMutex (&sec_none, false, buf);
if (!h)
goto errnout;
if (GetLastError () == ERROR_ALREADY_EXISTS)
{
CloseHandle (h);
return open_not_mine (flags);
}
fhandler_pipe *fhs[2];
if (create (fhs, 0, flags, true))
{
CloseHandle (h);
goto errout;
}
set_flags (fhs[0]->get_flags ());
set_io_handle (fhs[0]->get_handle ());
set_output_handle (fhs[1]->get_handle ());
guard = fhs[0]->guard;
read_state = fhs[0]->read_state;
writepipe_exists = fhs[1]->writepipe_exists;
orig_pid = fhs[0]->orig_pid;
id = fhs[0]->id;
delete (fhs[0]);
delete (fhs[1]);
set_use (1);
__small_sprintf (buf, "%x.%x", upand, myself->pid);
(void) GlobalAddAtom (buf);
goto out;
errnout:
__seterrno ();
errout:
res = 0;
out:
debug_printf ("returning %d, errno %d", res, get_errno ());
return res;
}
int
fhandler_fifo::dup (fhandler_base * child)
{
int res = fhandler_pipe::dup (child);
if (!res)
{
fhandler_fifo *ff = (fhandler_fifo *) child;
if (!DuplicateHandle (hMainProc, get_output_handle (), hMainProc,
&ff->get_output_handle (), false, true,
DUPLICATE_SAME_ACCESS))
{
child->close ();
res = -1;
}
}
return 0;
}