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newlib/winsup/cygwin/fhandler_fifo.cc

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/* fhandler_fifo.cc - See fhandler.h for a description of the fhandler classes.
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 <w32api/winioctl.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"
/* This is only to be used for writers. When reading,
STATUS_PIPE_EMPTY simply means there's no data to be read. */
#define STATUS_PIPE_IS_CLOSED(status) \
({ NTSTATUS _s = (status); \
_s == STATUS_PIPE_CLOSING \
|| _s == STATUS_PIPE_BROKEN \
|| _s == STATUS_PIPE_EMPTY; })
fhandler_fifo::fhandler_fifo ():
fhandler_base (), read_ready (NULL), write_ready (NULL),
listen_client_thr (NULL), lct_termination_evt (NULL), nclients (0),
nconnected (0)
{
pipe_name_buf[0] = L'\0';
need_fork_fixup (true);
}
PUNICODE_STRING
fhandler_fifo::get_pipe_name ()
{
if (!pipe_name_buf[0])
{
__small_swprintf (pipe_name_buf, L"%S-fifo.%08x.%016X",
&cygheap->installation_key, get_dev (), get_ino ());
RtlInitUnicodeString (&pipe_name, pipe_name_buf);
}
return &pipe_name;
}
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
what = "writer";
debug_only_printf ("arming %s", what);
#endif
bool res = SetEvent (h);
if (!res)
#ifdef DEBUGGING
debug_printf ("SetEvent for %s failed, %E", what);
#else
debug_printf ("SetEvent failed, %E");
#endif
return res;
}
static HANDLE
create_event ()
{
NTSTATUS status;
OBJECT_ATTRIBUTES attr;
HANDLE evt = NULL;
InitializeObjectAttributes (&attr, NULL, 0, NULL, NULL);
status = NtCreateEvent (&evt, EVENT_ALL_ACCESS, &attr,
NotificationEvent, FALSE);
if (!NT_SUCCESS (status))
__seterrno_from_nt_status (status);
return evt;
}
static void
set_pipe_non_blocking (HANDLE ph, bool nonblocking)
{
NTSTATUS status;
IO_STATUS_BLOCK io;
FILE_PIPE_INFORMATION fpi;
fpi.ReadMode = FILE_PIPE_MESSAGE_MODE;
fpi.CompletionMode = nonblocking ? FILE_PIPE_COMPLETE_OPERATION
: FILE_PIPE_QUEUE_OPERATION;
status = NtSetInformationFile (ph, &io, &fpi, sizeof fpi,
FilePipeInformation);
if (!NT_SUCCESS (status))
debug_printf ("NtSetInformationFile(FilePipeInformation): %y", status);
}
/* The pipe instance is always in blocking mode when this is called. */
int
fifo_client_handler::connect ()
{
NTSTATUS status;
IO_STATUS_BLOCK io;
if (connect_evt)
ResetEvent (connect_evt);
else if (!(connect_evt = create_event ()))
return -1;
status = NtFsControlFile (fh->get_handle (), connect_evt, NULL, NULL, &io,
FSCTL_PIPE_LISTEN, NULL, 0, NULL, 0);
switch (status)
{
case STATUS_PENDING:
case STATUS_PIPE_LISTENING:
state = fc_connecting;
break;
case STATUS_PIPE_CONNECTED:
state = fc_connected;
set_pipe_non_blocking (fh->get_handle (), true);
break;
default:
__seterrno_from_nt_status (status);
return -1;
}
return 0;
}
int
fhandler_fifo::disconnect_and_reconnect (int i)
{
NTSTATUS status;
IO_STATUS_BLOCK io;
HANDLE ph = client[i].fh->get_handle ();
status = NtFsControlFile (ph, NULL, NULL, NULL, &io, FSCTL_PIPE_DISCONNECT,
NULL, 0, NULL, 0);
/* Short-lived. Don't use cygwait. We don't want to be interrupted. */
if (status == STATUS_PENDING
&& NtWaitForSingleObject (ph, FALSE, NULL) == WAIT_OBJECT_0)
status = io.Status;
if (!NT_SUCCESS (status))
{
__seterrno_from_nt_status (status);
return -1;
}
set_pipe_non_blocking (client[i].fh->get_handle (), false);
if (client[i].connect () < 0)
return -1;
if (client[i].state == fc_connected)
nconnected++;
return 0;
}
NTSTATUS
fhandler_fifo::npfs_handle (HANDLE &nph)
{
static NO_COPY SRWLOCK npfs_lock;
static NO_COPY HANDLE npfs_dirh;
NTSTATUS status = STATUS_SUCCESS;
OBJECT_ATTRIBUTES attr;
IO_STATUS_BLOCK io;
/* Lockless after first call. */
if (npfs_dirh)
{
nph = npfs_dirh;
return STATUS_SUCCESS;
}
AcquireSRWLockExclusive (&npfs_lock);
if (!npfs_dirh)
{
InitializeObjectAttributes (&attr, &ro_u_npfs, 0, NULL, NULL);
status = NtOpenFile (&npfs_dirh, FILE_READ_ATTRIBUTES | SYNCHRONIZE,
&attr, &io, FILE_SHARE_READ | FILE_SHARE_WRITE,
0);
}
ReleaseSRWLockExclusive (&npfs_lock);
if (NT_SUCCESS (status))
nph = npfs_dirh;
return status;
}
/* Called when a FIFO is first opened for reading and again each time
a new client is needed. Each pipe instance is created in blocking
mode so that we can easily wait for a connection. After it is
connected, it is put in nonblocking mode. */
HANDLE
fhandler_fifo::create_pipe_instance (bool first)
{
NTSTATUS status;
HANDLE npfsh;
HANDLE ph = NULL;
ACCESS_MASK access;
OBJECT_ATTRIBUTES attr;
IO_STATUS_BLOCK io;
ULONG hattr;
ULONG sharing;
ULONG nonblocking = FILE_PIPE_QUEUE_OPERATION;
ULONG max_instances = -1;
LARGE_INTEGER timeout;
status = npfs_handle (npfsh);
if (!NT_SUCCESS (status))
{
__seterrno_from_nt_status (status);
return NULL;
}
access = GENERIC_READ | FILE_READ_ATTRIBUTES | FILE_WRITE_ATTRIBUTES
| SYNCHRONIZE;
sharing = FILE_SHARE_READ | FILE_SHARE_WRITE;
hattr = OBJ_INHERIT;
if (first)
hattr |= OBJ_CASE_INSENSITIVE;
InitializeObjectAttributes (&attr, get_pipe_name (),
hattr, npfsh, NULL);
timeout.QuadPart = -500000;
status = NtCreateNamedPipeFile (&ph, access, &attr, &io, sharing,
first ? FILE_CREATE : FILE_OPEN, 0,
FILE_PIPE_MESSAGE_TYPE,
FILE_PIPE_MESSAGE_MODE,
nonblocking, max_instances,
DEFAULT_PIPEBUFSIZE, DEFAULT_PIPEBUFSIZE,
&timeout);
if (!NT_SUCCESS (status))
__seterrno_from_nt_status (status);
return ph;
}
/* Called when a FIFO is opened for writing. */
NTSTATUS
fhandler_fifo::open_pipe ()
{
NTSTATUS status;
HANDLE npfsh;
ACCESS_MASK access;
OBJECT_ATTRIBUTES attr;
IO_STATUS_BLOCK io;
ULONG sharing;
HANDLE ph = NULL;
status = npfs_handle (npfsh);
if (!NT_SUCCESS (status))
return status;
access = GENERIC_WRITE | SYNCHRONIZE;
InitializeObjectAttributes (&attr, get_pipe_name (), OBJ_INHERIT,
npfsh, NULL);
sharing = FILE_SHARE_READ | FILE_SHARE_WRITE;
status = NtOpenFile (&ph, access, &attr, &io, sharing, 0);
if (NT_SUCCESS (status))
set_io_handle (ph);
return status;
}
int
fhandler_fifo::add_client ()
{
fifo_client_handler fc;
fhandler_base *fh;
bool first = (nclients == 0);
if (nclients == MAX_CLIENTS)
{
set_errno (EMFILE);
return -1;
}
if (!(fc.dummy_evt = create_event ()))
return -1;
if (!(fh = build_fh_dev (dev ())))
{
set_errno (EMFILE);
return -1;
}
fc.fh = fh;
HANDLE ph = create_pipe_instance (first);
if (!ph)
goto errout;
fh->set_io_handle (ph);
fh->set_flags (get_flags ());
if (fc.connect () < 0)
{
fc.close ();
goto errout;
}
if (fc.state == fc_connected)
nconnected++;
client[nclients++] = fc;
return 0;
errout:
delete fh;
return -1;
}
/* Just hop to the listen_client_thread method. */
DWORD WINAPI
listen_client_func (LPVOID param)
{
fhandler_fifo *fh = (fhandler_fifo *) param;
return fh->listen_client_thread ();
}
/* Start a thread that listens for client connections. Whenever a new
client connects, it creates a new pipe_instance if necessary.
(There may already be an available instance if a client has
disconnected.) */
bool
fhandler_fifo::listen_client ()
{
if (!(lct_termination_evt = create_event ()))
return false;
listen_client_thr = CreateThread (NULL, PREFERRED_IO_BLKSIZE,
listen_client_func, (PVOID) this, 0, NULL);
if (!listen_client_thr)
{
__seterrno ();
HANDLE evt = InterlockedExchangePointer (&lct_termination_evt, NULL);
if (evt)
CloseHandle (evt);
return false;
}
return true;
}
DWORD
fhandler_fifo::listen_client_thread ()
{
while (1)
{
bool found;
HANDLE w[MAX_CLIENTS + 1];
int i;
DWORD wait_ret;
fifo_client_lock ();
found = false;
for (i = 0; i < nclients; i++)
switch (client[i].state)
{
case fc_invalid:
if (disconnect_and_reconnect (i) < 0)
{
fifo_client_unlock ();
goto errout;
}
/* Fall through. */
case fc_connected:
w[i] = client[i].dummy_evt;
break;
case fc_connecting:
found = true;
w[i] = client[i].connect_evt;
break;
case fc_unknown: /* Shouldn't happen. */
default:
break;
}
w[nclients] = lct_termination_evt;
int res = 0;
if (!found)
res = add_client ();
fifo_client_unlock ();
if (res < 0)
goto errout;
else if (!found)
continue;
if (!arm (read_ready))
{
__seterrno ();
goto errout;
}
/* Wait for a client to connect. */
wait_ret = WaitForMultipleObjects (nclients + 1, w, false, INFINITE);
i = wait_ret - WAIT_OBJECT_0;
if (i < 0 || i > nclients)
goto errout;
else if (i == nclients) /* Reader is closing. */
return 0;
else
{
fifo_client_lock ();
client[i].state = fc_connected;
nconnected++;
set_pipe_non_blocking (client[i].fh->get_handle (), true);
fifo_client_unlock ();
yield ();
}
}
errout:
ResetEvent (read_ready);
return -1;
}
int
fhandler_fifo::open (int flags, mode_t)
{
enum
{
success,
error_errno_set,
error_set_errno
} res;
bool reader, writer, duplexer;
/* 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:
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);
if (reader)
nohandle (true);
/* Create control events for this named pipe */
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];
__small_sprintf (npbuf, "r-event.%08x.%016X", get_dev (), get_ino ());
if (!(read_ready = CreateEvent (sa_buf, duplexer, false, npbuf)))
{
debug_printf ("CreateEvent for %s failed, %E", npbuf);
res = error_set_errno;
goto out;
}
npbuf[0] = 'w';
if (!(write_ready = CreateEvent (sa_buf, false, false, npbuf)))
{
debug_printf ("CreateEvent for %s failed, %E", npbuf);
res = error_set_errno;
goto out;
}
/* If we're reading, start the listen_client thread (which should
signal read_ready), and wait for a writer. */
if (reader)
{
if (!listen_client ())
{
debug_printf ("create of listen_client thread failed");
res = error_errno_set;
goto out;
}
/* Wait for the listen_client thread to create the pipe and
signal read_ready. This should be quick. */
HANDLE w[2] = { listen_client_thr, read_ready };
switch (WaitForMultipleObjects (2, w, FALSE, INFINITE))
{
case WAIT_OBJECT_0:
debug_printf ("listen_client_thread exited unexpectedly");
DWORD err;
GetExitCodeThread (listen_client_thr, &err);
__seterrno_from_win_error (err);
res = error_errno_set;
goto out;
break;
case WAIT_OBJECT_0 + 1:
if (!arm (read_ready))
{
res = error_set_errno;
goto out;
}
break;
default:
res = error_set_errno;
goto out;
break;
}
if (!duplexer && !wait (write_ready))
{
res = error_errno_set;
goto out;
}
else
res = success;
}
/* If we're writing, wait for read_ready and then connect to the
pipe. This should always succeed quickly if the reader's
listen_client thread is running. Then signal write_ready. */
if (writer)
{
if (!wait (read_ready))
{
res = error_errno_set;
goto out;
}
NTSTATUS status = open_pipe ();
if (!NT_SUCCESS (status))
{
debug_printf ("create of writer failed");
__seterrno_from_nt_status (status);
res = error_errno_set;
goto out;
}
else if (!arm (write_ready))
{
res = error_set_errno;
goto out;
}
else
{
set_pipe_non_blocking (get_handle (), true);
res = success;
}
}
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 ());
if (listen_client_thr)
CloseHandle (listen_client_thr);
}
debug_printf ("res %d", res);
return res == success;
}
off_t
fhandler_fifo::lseek (off_t offset, int whence)
{
debug_printf ("(%D, %d)", offset, whence);
set_errno (ESPIPE);
return -1;
}
bool
fhandler_fifo::wait (HANDLE h)
{
#ifdef DEBUGGING
const char *what;
if (h == read_ready)
what = "reader";
else
what = "writer";
#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;
}
}
ssize_t __reg3
fhandler_fifo::raw_write (const void *ptr, size_t len)
{
ssize_t ret = -1;
NTSTATUS status;
IO_STATUS_BLOCK io;
status = NtWriteFile (get_handle (), NULL, NULL, NULL, &io,
(PVOID) ptr, len, NULL, NULL);
if (NT_SUCCESS (status))
{
/* NtWriteFile returns success with # of bytes written == 0 in
case writing on a non-blocking pipe fails if the pipe buffer
is full. */
if (io.Information == 0)
set_errno (EAGAIN);
else
ret = io.Information;
}
else if (STATUS_PIPE_IS_CLOSED (status))
{
set_errno (EPIPE);
raise (SIGPIPE);
}
else
__seterrno_from_nt_status (status);
return ret;
}
void __reg3
fhandler_fifo::raw_read (void *in_ptr, size_t& len)
{
size_t orig_len = len;
/* Start the listen_client thread if necessary (e.g., after dup or fork). */
if (!listen_client_thr && !listen_client ())
goto errout;
while (1)
{
if (nconnected == 0) /* EOF */
{
len = 0;
return;
}
/* Poll the connected clients for input. */
fifo_client_lock ();
for (int i = 0; i < nclients; i++)
if (client[i].state == fc_connected)
{
len = orig_len;
client[i].fh->fhandler_base::raw_read (in_ptr, len);
ssize_t nread = (ssize_t) len;
if (nread > 0)
{
fifo_client_unlock ();
return;
}
else if (nread < 0 && GetLastError () != ERROR_NO_DATA)
{
fifo_client_unlock ();
goto errout;
}
else if (nread == 0) /* Client has disconnected. */
{
client[i].state = fc_invalid;
nconnected--;
}
}
fifo_client_unlock ();
if (is_nonblocking ())
{
set_errno (EAGAIN);
goto errout;
}
else
{
/* Allow interruption. Copied from
fhandler_socket_unix::open_reparse_point. */
pthread_testcancel ();
if (cygwait (NULL, cw_nowait, cw_sig_eintr) == WAIT_SIGNALED
&& !_my_tls.call_signal_handler ())
{
set_errno (EINTR);
goto errout;
}
/* Don't hog the CPU. */
Sleep (1);
}
}
errout:
len = -1;
}
int __reg2
fhandler_fifo::fstatvfs (struct statvfs *sfs)
{
fhandler_disk_file fh (pc);
fh.get_device () = FH_FS;
return fh.fstatvfs (sfs);
}
int
fifo_client_handler::close ()
{
int res = 0;
if (fh)
res = fh->close ();
if (connect_evt)
CloseHandle (connect_evt);
if (dummy_evt)
CloseHandle (dummy_evt);
return res;
}
int
fhandler_fifo::close ()
{
int res = 0;
HANDLE evt = InterlockedExchangePointer (&lct_termination_evt, NULL);
HANDLE thr = InterlockedExchangePointer (&listen_client_thr, NULL);
if (thr)
{
if (evt)
SetEvent (evt);
WaitForSingleObject (thr, INFINITE);
DWORD err;
GetExitCodeThread (thr, &err);
if (err)
debug_printf ("listen_client_thread exited with code %d", err);
CloseHandle (thr);
}
if (evt)
CloseHandle (evt);
if (read_ready)
CloseHandle (read_ready);
if (write_ready)
CloseHandle (write_ready);
for (int i = 0; i < nclients; i++)
if (client[i].close () < 0)
res = -1;
return fhandler_base::close () || res;
}
int
fhandler_fifo::dup (fhandler_base *child, int flags)
{
if (fhandler_base::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::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);
}
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