newlib-cygwin/winsup/cygwin/fhandler_mailslot.cc

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/* fhandler_mailslot.cc. See fhandler.h for a description of the fhandler classes.
Copyright 2005, 2007 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 "cygerrno.h"
#include "security.h"
#include "path.h"
#include "fhandler.h"
#include "ntdll.h"
/**********************************************************************/
/* fhandler_mailslot */
fhandler_mailslot::fhandler_mailslot ()
: fhandler_base ()
{
}
int __stdcall
fhandler_mailslot::fstat (struct __stat64 *buf)
{
debug_printf ("here");
fhandler_base::fstat (buf);
if (is_auto_device ())
{
buf->st_mode = S_IFCHR | S_IRUSR | S_IWUSR;
buf->st_uid = geteuid32 ();
buf->st_gid = getegid32 ();
buf->st_nlink = 1;
buf->st_blksize = PREFERRED_IO_BLKSIZE;
time_as_timestruc_t (&buf->st_ctim);
buf->st_atim = buf->st_mtim = buf->st_birthtim = buf->st_ctim;
}
return 0;
}
int
fhandler_mailslot::open (int flags, mode_t mode)
{
int res = 0;
NTSTATUS status;
IO_STATUS_BLOCK io;
OBJECT_ATTRIBUTES attr;
HANDLE x;
LARGE_INTEGER timeout;
switch (flags & O_ACCMODE)
{
case O_RDONLY: /* Server */
timeout.QuadPart = (flags & O_NONBLOCK) ? 0LL : 0x8000000000000000LL;
status = NtCreateMailslotFile (&x, GENERIC_READ | SYNCHRONIZE,
pc.get_object_attr (attr, sec_none),
&io, FILE_SYNCHRONOUS_IO_NONALERT,
0, 0, &timeout);
if (!NT_SUCCESS (status))
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{
/* FIXME: It's not possible to open the read side of an existing
mailslot again. You'll get a handle, but using it in ReadFile
returns ERROR_INVALID_PARAMETER. On the other hand,
NtCreateMailslotFile returns with STATUS_OBJECT_NAME_EXISTS if
the mailslot has been created already.
So this is an exclusive open for now. *Duplicating* read side
handles works, though, so it might be an option to duplicate
the handle from the first process to the current process for
opening the mailslot. */
#if 0
if (status != STATUS_OBJECT_NAME_COLLISION)
{
__seterrno_from_nt_status (status);
break;
}
status = NtOpenFile (&x, GENERIC_READ | SYNCHRONIZE,
pc.get_object_attr (attr, sec_none), &io,
FILE_SHARE_VALID_FLAGS,
FILE_SYNCHRONOUS_IO_NONALERT);
#endif
if (!NT_SUCCESS (status))
{
__seterrno_from_nt_status (status);
break;
}
}
set_io_handle (x);
set_flags (flags, O_BINARY);
res = 1;
set_open_status ();
break;
case O_WRONLY: /* Client */
/* The client is the DLL exclusively. Don't allow opening from
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application code. */
extern fhandler_mailslot *dev_kmsg;
if (this != dev_kmsg)
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{
set_errno (EPERM); /* As on Linux. */
break;
}
status = NtOpenFile (&x, GENERIC_WRITE | SYNCHRONIZE,
pc.get_object_attr (attr, sec_none), &io,
FILE_SHARE_VALID_FLAGS,
FILE_SYNCHRONOUS_IO_NONALERT);
if (!NT_SUCCESS (status))
{
__seterrno_from_nt_status (status);
break;
}
set_io_handle (x);
set_flags (flags, O_BINARY);
res = 1;
set_open_status ();
break;
default:
set_errno (EINVAL);
break;
}
return res;
}
int
fhandler_mailslot::write (const void *ptr, size_t len)
{
/* Check for 425/426 byte weirdness */
if (len == 425 || len == 426)
{
char buf[427];
buf[425] = buf[426] = '\0';
memcpy (buf, ptr, len);
return raw_write (buf, 427);
}
return raw_write (ptr, len);
}
int
fhandler_mailslot::ioctl (unsigned int cmd, void *buf)
{
int res = -1;
NTSTATUS status;
IO_STATUS_BLOCK io;
switch (cmd)
{
case FIONBIO:
{
FILE_MAILSLOT_SET_INFORMATION fmsi;
fmsi.ReadTimeout.QuadPart = buf ? 0LL : 0x8000000000000000LL;
status = NtSetInformationFile (get_handle (), &io, &fmsi, sizeof fmsi,
FileMailslotSetInformation);
if (!NT_SUCCESS (status))
{
debug_printf ("NtSetInformationFile (%X): %08x",
fmsi.ReadTimeout.QuadPart, status);
__seterrno_from_nt_status (status);
break;
}
}
/*FALLTHRU*/
default:
res = fhandler_base::ioctl (cmd, buf);
break;
}
return res;
}