- 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.
- After commit 095972ce5b, charset
conversion in mintty is broken if charset is set to other than
UTF-8. This seems to be caused because mintty does not set locale
yet at fork() call. This patch changes the timing of set_locale()
call again to avoid this issue.
- If native app is exec()'ed in a new pty, setup_locale() loses the
chance to be called. For example, with "mintty -e cmd", charset
conversion does not work as expected. This patch fixes the issue.
This patch has been inspired by the Linux kernel patch
294f69e662d1 compiler_attributes.h: Add 'fallthrough' pseudo keyword for switch/case use
written by Joe Perches <joe AT perches DOT com> based on an idea from
Dan Carpenter <dan DOT carpenter AT oracle DOT com>. The following text
is from the original log message:
Reserve the pseudo keyword 'fallthrough' for the ability to convert the
various case block /* fallthrough */ style comments to appear to be an
actual reserved word with the same gcc case block missing fallthrough
warning capability.
All switch/case blocks now should end in one of:
break;
fallthrough;
goto <label>;
return [expression];
continue;
In C mode, GCC supports the __fallthrough__ attribute since 7.1,
the same time the warning and the comment parsing were introduced.
Cygwin-only: add an explicit -Wimplicit-fallthrough=5 to the build
flags.
- After commit 0365031ce1, key input
becomes not working by following steps.
1) Start cmd.exe in mintty.
2) Open another mintty.
3) Execute "echo AAA > /dev/pty*" (pty* is the pty opened in 1.)
This patch fixes the issue.
- Return value of eat_readahead() is redefined. The return values
of fhandler_termios::eat_readahead() and fhandler_pty_slave::
eat_readahead() were little bit different. This patch unifies
them to number of bytes eaten by eat_readahead().
- Considerration for raixget() is added to fhandler_pty_master::
accept_input() code.
- Transfering contents of read ahead buffer in
fhandler_pty_master::transfer_input_to_pcon() is removed since
it is not necessary.
- fhandler_pty_slave::eat_readahead() ckecks EOL only when ICANON
is set.
- Guard for _POSIX_VDISABLE is added in checking EOL.
- If vim is started from WSL (Ubuntu) which is executed in pseudo
console in mintty, shift key and ctrl key do not work. Though
this issue is similar to the issue resolved by commit
4527541ec6, that commit is not
effective for this issue. This patch fixes the issue by discarding
"CSI > Pm m" in fhandler_pty_master::pty_master_fwd_thread().
- 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.
- If the output of non-cygwin apps is browsed using less, screen is
ocasionally distorted after less exits. This frequently happens
if cmd.exe is executed after less. This patch fixes the issue.
- In current pty, the window title can not be set from non-cygwin
program due to the code which prevents overwriting the window
title to "cygwin-console-helper.exe" in fhandler_pty_master::pty_
master_fwd_thread(). This patch fixes the issue.
- 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.
- The number of slaves attached to pseudo console is used only for
triggering redraw screen. Counting was not only needless, but also
did not work as expected. This patch removes the code for counting.
- After commit 071b8e0cbd, the problem
reported in https://cygwin.com/pipermail/cygwin/2020-May/244873.html
occurs. This is due to freeing console device accidentally rather
than pseudo console. This patch makes sure to call FreeConsole()
only if the process is attached to the pseudo console of the current
pty.
When `cygwin-console-helper.exe` is either missing, or corresponds to a
different Cygwin runtime, we currently wait forever while setting up
access to the pseudo console, even long after the process is gone that
was supposed to signal that it set up access to the pseudo console.
Let's handle that more gracefully: if the process exited without
signaling, we cannot use the pseudo console. In that case, let's just
fall back to not using it.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
fhandler_socket_unix::fixup_after_exec incorrectly calls
fhandler_socket_unix::fixup_after_fork with a NULL parent process
handle. Not only that calling DuplicateHandle with a NULL parent
handle fails, but it's utterly wrong trying to duplicate the handles
at all here.
Rather just set some important values to NULL and reopen the shared
memory region. Create a fixup_helper method to call common code from
fixup_after_fork and fixup_after_exec.
Add comments to other invocations of fixup_after_fork with NULL
handle to mark them as correct this way.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
- In push_to_pcon_screenbuffer(), open() and ioctl() are called.
Since push_to_pcon_screenbuffer() is called in read() and write(),
errno which is set in read() and write() code may be overwritten
in open() or ioctl() call. This patch prevent this situation.
- PTY has a bug reported in:
https://cygwin.com/ml/cygwin/2020-02/msg00067.html.
This is the result of state mismatch between real pseudo console
attaching state and state variable. This patch fixes the issue.
- PTY has a problem that the key input, which is typed during
windows native app is running, disappear when it returns to shell.
(Problem 3 in https://cygwin.com/ml/cygwin/2020-02/msg00007.html)
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 patch realize transfering input data between these two pipes.
- Debug codes used in the early stage of pseudo console support are
removed. (Regarding ALWAYS_USE_PCON and USE_API_HOOK) Along with
this, the codes related to this change are organized.
- PTY code has a problem that tcsh is terminated if the following
command is executed.
true; chcp &
This seems to be caused by invalid pointer access which occurs
when the process exits during the kill() code is execuetd. This
patch avoids the issue by not using kill().
- After commit 6cc299f0e2, outputs of
cygwin programs which call both printf() and WriteConsole() are
frequently distorted. This patch fixes the issue.
- The cause of the problem reported in
https://www.cygwin.com/ml/cygwin/2020-01/msg00220.html is that the
chars input before dup() cannot be read from the new file descriptor.
This is because the readahead buffer (rabuf) in the console is newly
created by dup(), and does not inherit from the parent. This patch
fixes the issue.
- For programs which does not work properly with pseudo console,
disable_pcon in environment CYGWIN is introduced. If disable_pcon
is set, pseudo console support is disabled.
- For programs compiled with -mwindows option, reopening slave is
needed in push_to_pcon_screenbuffer(), however, it was not at
appropriate place. This causes the problem reported in
https://www.cygwin.com/ml/cygwin/2020-01/msg00161.html. This
patch fixes the issue.
- Though this rarely happens, sometimes the first printing of non-
cygwin process does not displayed correctly. To fix this issue,
the code for waiting for forwarding by master_fwd_thread is revised.
- After commit e1a0775dc0, the problem
reported in https://www.cygwin.com/ml/cygwin/2020-01/msg00093.html
occurs. For Gnu scren and tmux, calling FreeConsole() on pty close
is necessary. However, if FreeConsole() is called, cygwin setup
with '-h' option does not work. Therefore, the commit
e1a0775dc0 delayed closing pty.
This is the cause of the problem above. Now, instead of delaying
pty close, FreeConsole() is not called if the process is non cygwin
processes such as cygwin setup.
- Special function keys such as arrow keys or function keys do not
work in ConEmu with cygwin-connector after commit
6a06c6bc8f. This patch fixes the
issue.
- PTY code which support pseudo console has a problem that causes
handle leaks. Four of these are bug in pty code, and the other
one seems to be a bug of Windows10. ClosePseudoConsole() fails
to close one internal handle. This patch fixes the issue.
- If two PTYs are opened in the same process and the first one
is closed, the helper process for the first PTY remains running.
This patch fixes the issue.
- Even with commit fe512b2b12, pty
still has a problem in ESC[?3h and ESC[?3l handling if invalid
sequence such as ESC[?$ is sent. This patch fixes the issue.
- Pseudo console clears console screen buffer if ESC[?3h or ESC[?3l
is sent. However, xterm/vt100 does not clear screen. This cause
mismatch between real screen and console screen buffer. Therefore,
this patch triggers redraw screen in that situation so that the
synchronization is done on the next execution of native app.
This solves the problem reported in:
https://www.cygwin.com/ml/cygwin-patches/2019-q4/msg00116.html
- Previously, pty cleared screen at startup for synchronization
between the real screen and console screen buffer for pseudo
console. With this patch, instead of clearing screen, the screen
is redrawn when the first native program is executed after pty
is created. In other words, synchronization is deferred until
the native app is executed. Moreover, this realizes excluding
$TERM dependent code.
Takashi Yano
Takashi Yano via Cygwin-patches
Corinna Vinschen
Johannes Schindelin