We already fetched the correct SECURITY_ATTRIBUTES at the start of
fhandler_pipe::create, so using another SECURITY_ATTRIBUTES object for
the mutex and semaphore objects doesn't make much sense.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
select_sem gets created on the read side with inheritence settings
depending on the O_CLOEXEC flag. Then it gets duplicated to the write
side with unconditional inheritence. Fix that.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
Fold all code branches potentially having read or written data into
a single if branch, so signalling select_sem catches all cases.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
Rename fhandler_pipe_and_fifo::max_atomic_write to pipe_buf_size.
This reflect its actual meaning better. The fhandler_pipe_and_fifo
constructor initializes it to DEFAULT_PIPEBUFSIZE (== 64K), which is
the buffer size for the windows pipes created by fhandler_pipe and
fhandler_fifo. But if we inherit a stdio pipe handle from a
non-Cygwin process, the buffer size could be different.
To remedy this, add a method fhandler_pipe::set_pipe_buf_size that
queries the OS for the pipe buffer size, and use it in
dtable::init_std_file_from_handle.
In blocking mode, the underlying IO must always be terminated,
one way or the other, to make sure the application knows the exact
state after returning from the IO function. Therefore, always call
CancelIo in blocking mode.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
Just cancelling a thread doesn't cancel async IO started by this thread.
Fix this by returning from cygwait and calling CancelIo before canceling
self.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
- By guarding read with read_mtx, no more than one ReadFile can
be called simultaneously. So couting read handles is no longer
necessary.
- Make raw_read code as similar as possible to raw_write code.
This is a parent of fhandler_pipe and fhandler_fifo for code that is
common between the two classes. Currently it just contains
max_atomic_write and raw_write(). The latter is identical to what
used to be fhandler_pipe::raw_write().
FILE_PIPE_LOCAL_INFORMATION::WriteQuotaAvailable is unreliable.
Usually WriteQuotaAvailable on the write side reflects the space
available in the inbound buffer on the read side. However, if a
pipe read is currently pending, WriteQuotaAvailable on the write side
is decremented by the number of bytes the read side is requesting.
So it's possible (even likely) that WriteQuotaAvailable is 0, even
if the inbound buffer on the read side is not full. This can lead to
a deadlock situation: The reader is waiting for data, but select
on the writer side assumes that no space is available in the read
side inbound buffer.
This patch implements a workaround by never trying to read more than
half the buffer size blocking if the read buffer is empty. This first
cut tries to take the number of open readers into account by reducing
the amount of requested bytes accordingly.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
POSIX requires atomicity for non-blocking writes <= PIPE_BUF bytes
and writing of at least 1 byte if any buffer space is left.
Windows NtWriteFile returns STATUS_SUCCESS and "0 bytes written"
if the write doesn't match buffer space. Fix this discrepancy.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
The buffer pointer is incremented by "chunk", which is what we
typically try to write, but this isn't what actually got written.
Increment the buffer pointer by what we actually wrote, as returned
by NtWriteFile.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
The read handles of pipes created by CreateNamedPipe don't have
FILE_WRITE_ATTRIBUTES access unless the pipe is created with
PIPE_ACCESS_DUPLEX. This causes set_pipe_non_blocking to fail on such
handles. To fix this, add a helper function nt_create, which uses
NtCreateNamedPipeFile instead of CreateNamedPipe and gives us more
flexibility in setting access rights.
Use this helper function in fhandler_pipe::create (fhandler_pipe *[2],
unsigned, int), which is the version of fhandler_pipe::create used by
the pipe and pipe2 system calls.
For convenience, also add a static member function
fhandler_pipe::npfs_handle similar to those used by fhandler_fifo and
fhandler_socket_unix.
Add methods 'set_pipe_non_blocking' and 'fcntl' to keep the blocking
mode of the Windows pipe in sync with that of the fhandler_pipe
object. This applies to pipes created with the 'pipe' and 'pipe2'
system calls.
Previously fhandler_pipe was derived from fhandler_base_overlapped,
which we are going to remove in a future commit. Make minimal changes
so that the build still succeeds.
Analyzing the fhandler::copyto logic shows that the fhandler_base::reset
method was only called from copyto anyway.
Trying to convert reset to a protected method uncovered that the copyto
method is actually thought upside down from an object oriented POV.
Rather than calling copyto, manipulating the object given as parameter,
rename the method to copy_from, which manipulates the calling object
itself with data from the object given as parameter.
Eventually make reset a protected method and rename it to
_copy_from_reset_helper to clarify it's only called from copy_from.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
path_conv::reset_conv_handle is only called after fhandler::copyto
has been called. This duplicated the path_conv_handle if there was
one, so just setting the conv handle to NULL potentially produces a
handle leak. Replace reset_conv_handle calls with calls to
close_conv_handle and drop the reset_conv_handle method.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
The symlink target of /proc/PID/fd files pointing to pipes and
sockets are just artificial filenames referencing the object using
some internal number. The pipe open code expects a path specifying
process pid and the internal number so it access the right process
and pipe.
- Set the posix path of the pipe to the simple pipe name only,
as it shows up in /proc/PID/fd. A /proc/self prefix is just
as wrong as a /dev/fd prefix.
- Revert thinko in fhandler_pipe::open expecting the name as
/proc/self/fd/... In fact this should never happen.
- Fix up the path before re-opening the pipe instead.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
Takashi Yano
Corinna Vinschen
Ken Brown