reuse fhandler_virtual implementation to implement read and lseek.
The output from read(2) is modelled after the output when reading
from an mq file on Linux.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
The POSIX entry points are just wrappers now, calling into
fhandler_mqueue. While at it, eliminate mqi_flags, replace with
standard fhandler nonblocking flag.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
The mq_open call is just a framework now. This patch moves the
entire functionality into fhandler_mqueue. To support standard
OS calls (as on Linux), make fhandler_mqueue a derived class from
fhandler_disk_file and keep the base handle the handle to the
default stream, to allow implementing O_PATH functionlaity as well
as reading from the file and NOT reading binary message queue data.
Implement a standard fhandler_mqueue::open method, allowing, for
instance, to touch a file under /dev/mqueue and if it doesn't exist,
to create a message queue file.
FIXME: This introduces a BAD HACK into path_conv::check, which needs
reviewing.
Keep the posix path intact in the fhandler, and change get_proc_fd_name
accordingly to return only the basename plus leading slash for
/proc/<PID>/fd.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
This encapsulated creation, duplication, and closing of all
Windows objects connected to the message queue in the fhandler.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
build_fh_dev can take the POSIX object name as parameter anyway,
so use that and drop from mqinfo call.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
So far, the mqd_t type returned a pointer to an allocated
area under the hood. The mutex and event objects attached
to the message queue were implemented as inheritable types.
As unfortunate side effect the HANDLEs to these objects
were inherited by exec'd child processes, even though all
other message queue properties are not inherted, per POSIX.
Fix this by converting an mqd_t to a descriptor, and create a
matching fhandler_mqueue object to handle various aspects of
the message queues inside the fhandler. Especially, create the
IPC objects as non-inheritable and duplicate the HANDLEs as
part of the fixup_after_fork mechanism.
Drop using mmap and create the memory map with NT functions.
This allows to control duplication of handle and mapping in the
forked child process, without the requirement to regenerate the
map in the same spot. It also allows to dup() the descriptor,
as on Linux, albeit this isn't implemented yet.
This patch is the first cut. There's a bit more to do, like
moving more functionality from the POSIX functions into the
fhandler and making sure the mqd_t type can't be used in other
descriptor-related functions willy-nilly.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
- Currently, functions/variables regarding the handles for cygwin
apps are with "_cyg", and those of handles for non-cygwin apps
are without "_cyg", such as get_handle_cyg() and get_handle().
This patch renames these to the names without "_nat" and with
"_nat" respectively, such as get_handle() and get_handle_nat().
This was done for the fhandler_socket_local class in commits
3a2191653a, 141437d374, and 477121317d, but the fhandler_socket_unix
class was overlooked.
Previously fstat on a FIFO would call fhandler_base::fstat.
The latter is not appropriate if fhandler_fifo::open has already been
called (and O_PATH is not set), for the following reason. If a FIFO
has been opened as a writer or duplexer, then it has an io_handle that
is a pipe handle rather than a file handle. fhandler_base::fstat will
use this handle and potentially return incorrect results. If the FIFO
has been opened as a reader, then it has no io_handle, and a call to
fhandler_base::fstat will lead to a call to fhandler_base::open.
Opening the fhandler a second time can change it in undesired ways;
for example, it can modify the flags and status_flags.
The new fhandler_fifo::fstat avoids these problems by creating an
fhandler_disk_file and calling its fstat method in case
fhandler_fifo::open has already been called and O_PATH is not set.
This only affects the very seldom bordercase of apps calling setmode(fd,
0) on fhandlers not calling fhandler_base::set_open_status(). All
fhandlers not calling set_open_status() are binary mode only, but the
way reset_to_open_binmode worked, calling setmode(fd, 0) would have
"reset" their open flags to O_TEXT accidentally.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
- If ENABLE_LINE_INPUT is set, Ctrl-S is handled by Windows if the
OS is Windows 7. This conflicts with Ctrl-S handling in cygwin
console code. This patch unsets ENABLE_LINE_INPUT flag in cygwin
and set it when native app is executed.
- Currently, Ctrl-Z, Ctrl-\ and SIGWINCH does not work in console
if the process does not call read() or select(). This is because
these are processed in process_input_message() which is called
from read() or select(). This is a long standing issue of console.
Addresses:
https://cygwin.com/pipermail/cygwin/2020-May/244898.htmlhttps://cygwin.com/pipermail/cygwin/2021-February/247779.html
With this patch, new thread which handles only input signals is
introduced so that Crtl-Z, etc. work without calling read() or
select(). Ctrl-S and Ctrl-Q are also handled in this thread.
- Currently, input transfer is performed every time one line is read(),
if the non-cygwin app is running in the background. With this patch,
transfer is triggered by setpgid() rather than read() so that the
unnecessary input transfer can be reduced much in that situation.
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>
- After commit bb428520, there has been the disadvantage:
7) Pseudo console cannot be activated if it is already activated for
another process on same pty.
This patch clears this disadvantage.
- After commit bb428520, there has been the disadvantage:
2) The apps which use console API cannot be debugged with gdb. This
is because pseudo console is not activated since gdb uses
CreateProcess() rather than exec(). Even with this limitation,
attaching gdb to native app, in which pseudo console is already
activated, works.
This patch clears this disadvantage.
- PTY has a problem that the key input, which is typed during windows
native app is running, disappears when it returns to shell. This is
beacuse pty has two input pipes, one is for cygwin apps and the other
one is for native windows apps. The key input during windows native
program is running is sent to the second input pipe while cygwin
shell reads input from the first input pipe. This issue had been
fixed once by commit 29431fcb, however, the new implementation of
pseudo console support by commit bb428520 could not inherit this
feature. This patch realize transfering input data between these
two pipes bidirectionally by utilizing cygwin-console-helper process.
The helper process is launched prior to starting the non-cygwin app,
however, exits immediately unlike previous implementation.
The isdev_dev check in rmdir is unclean. Create a virtual method
fhandler_dev::rmdir to handle this transparently.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
- The functions pty_master_thread() and pty_master_fwd_thread()
should be static (i.e. should not access class member) because
the instance is deleted if the master is dup()'ed and the first
master is closed. In this case, because the dup()'ed instance
still exists, these master threads are also still alive even
though the instance has been deleted. As a result, accesing
class members in these functions causes accessi violation.
Addresses:
https://cygwin.com/pipermail/cygwin-developers/2021-January/012030.html
- After commit 232fde0e, pty changes console code page when the first
non-cygwin app is executed. If pty is started in real console device,
pty changes the code page of root console. This causes very annoying
result because changing code page changes the font of command prompt
if console is in legacy mode. This patch avoids this by creating a
new invisible console for the first pty started in console device.
- The function close_pseudoconsole() should be static so that it
can be safely called in spawn.cc even after the fhandler_pty_slave
instance has been deleted. That is, there is a problem with the
current code. This patch fixes the issue.
- If application changes the console mode, mode management introduced
by commit 10d8c278 will be corrupted. For example, stdout of jansi
v2.0.1 or later is piped to less, jansi resets the xterm mode flag
ENABLE_VIRTUAL_TERMINA_PROCESSING when jansi is terminated. This
causes garbled output in less because less needs this flag enabled.
This patch fixes the issue.
Replace the 'WCHAR pipe_name_buf[48]' class member by 'PWCHAR
pipe_name_buf', and allocate space for the latter as needed.
Change the default constructor to accommodate this change, and add a
destructor that frees the allocated space.
Also change get_pipe_name and clone to accommodate this change.
Both flags are outdated and collide with official flags in
sys/_default_fcntl.h, which may result in weird misbehaviour
of file functions.
O_NOSYMLINK is not used anyway.
O_DIROPEN is used in fhandler_virtual and derived classes.
The collision with O_NOFOLLOW results in spurious EISDIR
errors when, e. g., reading files in the registry.
fhandler_base::open_fs uses O_DIROPEN in the call to
fhandler_base::open, but it's not used in this context
further down the road.
Drop both flags and create an alternative "diropen" bool
flag in fhandler_virtual.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
- Pseudo console internally sends escape sequence CSI6n (query cursor
position) on startup of non-cygwin apps. If the terminal does not
support CSI6n, CreateProcess() hangs waiting for response. To prevent
hang, this patch disables pseudo console if the terminal does not
have CSI6n. This is checked on the first execution of non-cygwin
app using the following steps.
1) Check if the terminal support ANSI escape sequences by looking
into terminfo database. If terminfo has cursor_home (ESC [H),
the terminal is supposed to support ANSI escape sequences.
2) If the terminal supports ANSI escape sequneces, send CSI6n for
a test and wait for a responce for 40ms.
3) If there is a responce within 40ms, CSI6n is supposed to be
supported.
Also set-title capability is checked, and removes escape sequence
for setting window title if the terminal does not have the set-
title capability.
- In this implementation, pseudo console is created for each native
console app. Advantages and disadvantages of this implementation
over the previous implementation are as follows.
Advantages:
1) No performance degradation in pty output for cygwin process.
https://cygwin.com/pipermail/cygwin/2020-February/243858.html
2) Free from the problem caused by difference of behaviour of control
sequences between real terminal and pseudo console.
https://cygwin.com/pipermail/cygwin/2019-December/243281.htmlhttps://cygwin.com/pipermail/cygwin/2020-February/243855.html
3) Free from the problem in cgdb and emacs gud.
https://cygwin.com/pipermail/cygwin/2020-January/243601.htmlhttps://cygwin.com/pipermail/cygwin/2020-March/244146.html
4) Redrawing screen on executing native console apps is not necessary.
5) cygwin-console-helper is not necessary for the pseudo console
support.
6) The codes for pseudo console support are much simpler than that
of the previous one.
Disadvantages:
1) The cygwin program which calls console API directly does not work.
2) The apps which use console API cannot be debugged with gdb. This
is because pseudo console is not activated since gdb uses
CreateProcess() rather than exec(). Even with this limitation,
attaching gdb to native apps, in which pseudo console is already
activated, works.
3) Typeahead key inputs are discarded while native console app is
executed. Simirally, typeahead key inputs while cygwin app is
executed are not inherited to native console app.
4) Code page cannot be changed by chcp.com. Acctually, chcp works
itself and changes code page of its own pseudo console. However,
since pseudo console is recreated for another process, it cannot
inherit the code page.
5) system_printf() does not work after stderr is closed. (Same with
cygwin 3.0.7)
6) Startup time of native console apps is about 3 times slower than
previous implemenation.
7) Pseudo console cannot be activated if it is already activated for
another process on same pty.
The fifo_reader thread function and the function select.cc:peek_fifo()
can both change the state of a fifo_client_handler. These changes are
made under fifo_client_lock, so there is no race, but the changes can
still be incompatible.
Add code to make sure that only one of these functions can change the
state from its initial fc_listening state. Whichever function does
this calls the fhandler_fifo::record_connection method, which is now
public so that peek_fifo can call it.
Slightly modify that method to make it suitable for being called by
peek_fifo.
Make a few other small changes to the fifo_reader thread function to
change how it deals with the STATUS_PIPE_CLOSING value that can
(rarely) be returned by NtFsControlFile.
Add commentary to fhandler_fifo.cc to explain fifo_client connect
states and where they can be changed.
Don't try to read from fifo_client_handlers that are in the fc_closing
state. Experiments have shown that this always yields
STATUS_PIPE_BROKEN, so it just wastes a Windows system call.
Re-order the values in enum fifo_client_connect_state to reflect the
new status of fc_closing.
Rename the existing set_state() to query_and_set_state() to reflect
what it really does. (It queries the O/S for the pipe state.) Add a
new set_state() method, which is a standard setter, and a
corresponding getter get_state().
fhandler_fifo::take_ownership() is called from select.cc::peek_fifo
and fhandler_fifo::raw_read and could potentially block indefinitely
if something goes wrong. This is always undesirable in peek_fifo, and
it is undesirable in a nonblocking read. Fix this by adding a timeout
parameter to take_ownership.
Arbitrarily use a 1 ms timeout in peek_fifo and a 10 ms timeout in
raw_read. These numbers may have to be tweaked based on experience.
Replace the call to cygwait in take_ownership by a call to WFSO.
There's no need to allow interruption now that we have a timeout.
Use cygwait in take_ownership to allow interruption while waiting to
become owner. Return the cygwait return value or a suitable value to
indicate an error.
raw_read now checks the return value and acts accordingly.
Add a bool member 'last_read' to the fifo_client_handler structure,
which is set to true on a successful read. This is used by raw_read
as follows.
When raw_read is called, it first locates the writer (if any) for
which last_read is true. raw_read tries to read from that writer and
returns if there is input available. Otherwise, it proceeds to poll
all the writers, as before.
The effect of this is that if a writer writes some data that is only
partially read, the next attempt to read will continue to read from
the same writer. This should reduce the interleaving of output from
different writers.
When a reader opens, it needs to block if there are no writers open
(unless is is opened with O_NONBLOCK). This is easy for the first
reader to test, since it can just wait for a writer to signal that it
is open (via the write_ready event). But when a second reader wants
to open, all writers might have closed.
To check this, use a new '_nwriters' member of struct fifo_shmem_t,
which keeps track of the number of open writers. This should be more
reliable than the previous method.
Add nwriters_lock to control access to shmem->_nwriters, and remove
reader_opening_lock, which is no longer needed.
Previously only readers had access to the shared memory, but now
writers access it too so that they can increment _nwriters during
open/dup/fork/exec and decrement it during close.
Add an optional 'only_open' argument to create_shmem for use by
writers, which only open the shared memory rather than first trying to
create it. Since writers don't need to access the shared memory until
they have successfully connected to a pipe instance, they can safely
assume that a reader has already created the shared memory.
For debugging purposes, change create_shmem to return 1 instead of 0
when a reader successfully opens the shared memory after finding that
it had already been created.
Remove check_write_ready_evt, write_ready_ok_evt, and
check_write_ready(), which are no longer needed.
When opening a writer and looping to try to get a connection, recheck
read_ready at the top of the loop since the number of readers might
have changed.
To slightly speed up the process of opening the first reader, take
ownership immediately rather than waiting for the fifo_reader_thread
to handle it.
When the owning reader closes and there are still readers open, the
owner needs to wait for a new owner to be found before closing its
fifo_client handlers. This involves a loop in which dec_nreaders is
called at the beginning and inc_nreaders is called at the end. Any
other reader that tries to access shmem->_nreaders during this loop
will therefore get an inaccurate answer.
Fix this by adding an nreaders method and using it instead of
dec_nreaders and inc_nreaders. Also add nreaders_lock to control
access to the shmem->_nreaders.
Make various other changes to improve the reliability of finding a new
owner.
Use WSAIoctl(SIO_KEEPALIVE_VALS) on older systems.
Make sure that keep-alive timeout is equivalent to
TCP_KEEPIDLE + TCP_KEEPCNT * TCP_KEEPINTVL on older systems,
even with TCP_KEEPCNT being a fixed value on those systems.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
- Commit c4b060e3fe seems to be not
enough. Moreover, it does not work as expected at all in Win10
1809. This patch essentially reverts that commit and add another
fix. After all, the cause of the problem was a race issue in
switch_to_pcon_out flag. That is, this flag is set when native
app starts, however, it is delayed by wait_pcon_fwd(). Since the
flag is not set yet when less starts, the data which should go
into the output_handle accidentally goes into output_handle_cyg.
This patch fixes the problem more essentially for the cause of
the problem than previous one.
- After commit 29431fcb5b, the issue
reported in https://cygwin.com/pipermail/cygwin/2020-May/245057.html
occurs. This is caused by the following mechanism. Cygwin less
called from non-cygwin git is executed under /dev/cons* rather
than /dev/pty* because parent git process only inherits pseudo
console handle. Therefore, less sets ICANON flag for /dev/cons*
rather than original /dev/pty*. When pty is switched to non-cygwin
git process, line_edit() is used in fhandler_pty_master::write()
only to set input_available_event and read ahead buffer is supposed
to be flushed in accept_input(). However, ICANON flag is not set
for /dev/pty*, so accept_input() is not called unless newline
is entered. As a result, the input data remains in the read ahead
buffer. This patch fixes the issue.
This reverts commit 39a9cd9465.
There is no need to explicitly take ownership in fixup_after_exec; if
ownership transfer is needed, it will be taken care of by
fhandler_fifo::close when the parent closes. Moreover, closing the
parent's fifo_reader_thread can cause problems, such as the one
reported here:
https://cygwin.com/pipermail/cygwin-patches/2020q2/010235.html
Corinna Vinschen
Takashi Yano
Takashi Yano via Cygwin-patches
Ken Brown