newlib/winsup/cygwin/fhandler_fifo.cc

372 lines
9.0 KiB
C++

/* fhandler_fifo.cc - See fhandler.h for a description of the fhandler classes.
Copyright 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012
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 "miscfuncs.h"
#include "cygerrno.h"
#include "security.h"
#include "path.h"
#include "fhandler.h"
#include "dtable.h"
#include "cygheap.h"
#include "sigproc.h"
#include "cygtls.h"
#include "shared_info.h"
#include "ntdll.h"
#include "cygwait.h"
fhandler_fifo::fhandler_fifo ():
fhandler_base_overlapped (),
read_ready (NULL), write_ready (NULL)
{
max_atomic_write = DEFAULT_PIPEBUFSIZE;
need_fork_fixup (true);
}
#define fnevent(w) fifo_name (npbuf, w "-event")
#define fnpipe() fifo_name (npbuf, "fifo")
#define create_pipe(r, w) \
fhandler_pipe::create (sa_buf, (r), (w), 0, fnpipe (), open_mode)
char *
fhandler_fifo::fifo_name (char *buf, const char *what)
{
/* Generate a semi-unique name to associate with this fifo. */
__small_sprintf (buf, "%s.%08x.%016X", what, get_dev (),
get_ino ());
return buf;
}
inline PSECURITY_ATTRIBUTES
sec_user_cloexec (bool cloexec, PSECURITY_ATTRIBUTES sa, PSID sid)
{
return cloexec ? sec_user_nih (sa, sid) : sec_user (sa, sid);
}
bool inline
fhandler_fifo::arm (HANDLE h)
{
#ifdef DEBUGGING
const char *what;
if (h == read_ready)
what = "reader";
else if (h == write_ready)
what = "writer";
else
what = "overlapped event";
debug_only_printf ("arming %s", what);
#endif
bool res = SetEvent (h);
if (!res)
debug_printf ("SetEvent for %s failed, %E", res);
return res;
}
int
fhandler_fifo::open (int flags, mode_t)
{
enum
{
success,
error_errno_set,
error_set_errno
} res;
bool reader, writer, duplexer;
DWORD open_mode = FILE_FLAG_OVERLAPPED;
/* Determine what we're doing with this fhandler: reading, writing, both */
switch (flags & O_ACCMODE)
{
case O_RDONLY:
reader = true;
writer = false;
duplexer = false;
break;
case O_WRONLY:
writer = true;
reader = false;
duplexer = false;
break;
case O_RDWR:
open_mode |= PIPE_ACCESS_DUPLEX;
reader = true;
writer = false;
duplexer = true;
break;
default:
set_errno (EINVAL);
res = error_errno_set;
goto out;
}
debug_only_printf ("reader %d, writer %d, duplexer %d", reader, writer, duplexer);
set_flags (flags);
char char_sa_buf[1024];
LPSECURITY_ATTRIBUTES sa_buf;
sa_buf = sec_user_cloexec (flags & O_CLOEXEC, (PSECURITY_ATTRIBUTES) char_sa_buf,
cygheap->user.sid());
char npbuf[MAX_PATH];
/* Create control events for this named pipe */
if (!(read_ready = CreateEvent (sa_buf, duplexer, false, fnevent ("r"))))
{
debug_printf ("CreatEvent for %s failed, %E", npbuf);
res = error_set_errno;
goto out;
}
if (!(write_ready = CreateEvent (sa_buf, false, false, fnevent ("w"))))
{
debug_printf ("CreatEvent for %s failed, %E", npbuf);
res = error_set_errno;
goto out;
}
/* If we're reading, create the pipe, signal that we're ready and wait for
a writer.
FIXME: Probably need to special case O_RDWR case. */
if (!reader)
/* We are not a reader */;
else if (create_pipe (&get_io_handle (), NULL))
{
debug_printf ("create of reader failed");
res = error_set_errno;
goto out;
}
else if (!arm (read_ready))
{
res = error_set_errno;
goto out;
}
else if (!duplexer && !wait (write_ready))
{
res = error_errno_set;
goto out;
}
/* If we're writing, it's a little tricky since it is possible that
we're attempting to open the other end of a pipe which is already
connected. In that case, we detect ERROR_PIPE_BUSY, reset the
read_ready event and wait for the reader to allow us to connect
by signalling read_ready.
Once the pipe has been set up, we signal write_ready. */
if (writer)
{
int err;
while (1)
if (!wait (read_ready))
{
res = error_errno_set;
goto out;
}
else if ((err = create_pipe (NULL, &get_io_handle ())) == 0)
break;
else if (err == ERROR_PIPE_BUSY)
{
debug_only_printf ("pipe busy");
ResetEvent (read_ready);
}
else
{
debug_printf ("create of writer failed");
res = error_set_errno;
goto out;
}
if (!arm (write_ready))
{
res = error_set_errno;
goto out;
}
}
/* If setup_overlapped() succeeds (and why wouldn't it?) we are all set. */
if (setup_overlapped () == 0)
res = success;
else
{
debug_printf ("setup_overlapped failed, %E");
res = error_set_errno;
}
out:
if (res == error_set_errno)
__seterrno ();
if (res != success)
{
if (read_ready)
{
CloseHandle (read_ready);
read_ready = NULL;
}
if (write_ready)
{
CloseHandle (write_ready);
write_ready = NULL;
}
if (get_io_handle ())
CloseHandle (get_io_handle ());
}
debug_printf ("res %d", res);
return res == success;
}
bool
fhandler_fifo::wait (HANDLE h)
{
#ifdef DEBUGGING
const char *what;
if (h == read_ready)
what = "reader";
else if (h == write_ready)
what = "writer";
else
what = "overlapped event";
#endif
/* Set the wait to zero for non-blocking I/O-related events. */
DWORD wait = ((h == read_ready || h == write_ready)
&& get_flags () & O_NONBLOCK) ? 0 : INFINITE;
debug_only_printf ("waiting for %s", what);
/* Wait for the event. Set errno, as appropriate if something goes wrong. */
switch (cygwait (h, wait))
{
case WAIT_OBJECT_0:
debug_only_printf ("successfully waited for %s", what);
return true;
case WAIT_SIGNALED:
debug_only_printf ("interrupted by signal while waiting for %s", what);
set_errno (EINTR);
return false;
case WAIT_CANCELED:
debug_only_printf ("cancellable interruption while waiting for %s", what);
pthread::static_cancel_self (); /* never returns */
break;
case WAIT_TIMEOUT:
if (h == write_ready)
{
debug_only_printf ("wait timed out waiting for write but will still open reader since non-blocking mode");
return true;
}
else
{
set_errno (ENXIO);
return false;
}
break;
default:
debug_only_printf ("unknown error while waiting for %s", what);
__seterrno ();
return false;
}
}
void __stdcall
fhandler_fifo::raw_read (void *in_ptr, size_t& len)
{
size_t orig_len = len;
for (int i = 0; i < 2; i++)
{
fhandler_base_overlapped::raw_read (in_ptr, len);
if (len || i || WaitForSingleObject (read_ready, 0) != WAIT_OBJECT_0)
break;
/* If we got here, then fhandler_base_overlapped::raw_read returned 0,
indicating "EOF" and something has set read_ready to zero. That means
we should have a client waiting to connect.
FIXME: If the client CTRL-C's the open during this time then this
could hang indefinitely. Maybe implement a timeout? */
if (!DisconnectNamedPipe (get_io_handle ()))
{
debug_printf ("DisconnecttNamedPipe failed, %E");
goto errno_out;
}
else if (!ConnectNamedPipe (get_io_handle (), get_overlapped ())
&& GetLastError () != ERROR_IO_PENDING)
{
debug_printf ("ConnectNamedPipe failed, %E");
goto errno_out;
}
else if (!arm (read_ready))
goto errno_out;
else if (!wait (get_overlapped_buffer ()->hEvent))
goto errout; /* If wait() fails, errno is set so no need to set it */
len = orig_len; /* Reset since raw_read above set it to zero. */
}
return;
errno_out:
__seterrno ();
errout:
len = -1;
}
int __stdcall
fhandler_fifo::fstatvfs (struct statvfs *sfs)
{
fhandler_disk_file fh (pc);
fh.get_device () = FH_FS;
return fh.fstatvfs (sfs);
}
int
fhandler_fifo::close ()
{
CloseHandle (read_ready);
CloseHandle (write_ready);
return fhandler_base::close ();
}
int
fhandler_fifo::dup (fhandler_base *child, int flags)
{
if (fhandler_base_overlapped::dup (child, flags))
{
__seterrno ();
return -1;
}
fhandler_fifo *fhf = (fhandler_fifo *) child;
if (!DuplicateHandle (GetCurrentProcess (), read_ready,
GetCurrentProcess (), &fhf->read_ready,
0, true, DUPLICATE_SAME_ACCESS))
{
fhf->close ();
__seterrno ();
return -1;
}
if (!DuplicateHandle (GetCurrentProcess (), write_ready,
GetCurrentProcess (), &fhf->write_ready,
0, true, DUPLICATE_SAME_ACCESS))
{
CloseHandle (fhf->read_ready);
fhf->close ();
__seterrno ();
return -1;
}
return 0;
}
void
fhandler_fifo::fixup_after_fork (HANDLE parent)
{
fhandler_base_overlapped::fixup_after_fork (parent);
fork_fixup (parent, read_ready, "read_ready");
fork_fixup (parent, write_ready, "write_ready");
}
void
fhandler_fifo::set_close_on_exec (bool val)
{
fhandler_base::set_close_on_exec (val);
set_no_inheritance (read_ready, val);
set_no_inheritance (write_ready, val);
}