xterm 368 and mintty 3.5.1 implement a new feature to support
notification of terminal scaling via font zooming also if the terminal
text dimensions (rows/columns) stay unchanged, using
ioctl(TIOCSWINSZ), raising SIGWINCH;
this patches cygwin to support that scenario
- In commit bb93c6d7, the race issue was not completely fixed. In
the pseudo console inheritance, if the destination process to
which the ownership of pseudo console switches, is found but exits
before switching, the inheritance fails. Currently, this extremely
rarely happens. This patch fixes the issue.
- 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().
- Currently, names of output pipes are "pty%d-to-master" and "pty%d-
to-master-cyg" and names of input pipes are "pty%d-to-slave" and
"pty%d-from-master". With this patch, these pipes are renamed to
"pty%d-to-master-nat", "pty%d-to-master", "pty%d-from-master-nat"
and "pty%d-from-master" respectively.
- Currently, transfer input is triggered even if the stdin of native
app is not a pseudo console. With this patch it is triggered only
if the stdin is a pseudo console.
- If two non-cygwin apps are started simultaneously, attaching to
pseudo console sometimes fails. This is because the second app
trys to attach to the process not started yet. This patch avoids
the issue by attaching to the stub process rather than the other
non-cygwin app.
- Perhaps current code misunderstand meaning of the IGNBRK. As far
as I investigated, IGNBRK is concerned with break signal in serial
port but there is no evidence that it has effect to ignore Ctrl-C.
This patch stops ignoring Ctrl-C by IGNBRK for non-cygwin apps.
- If two non-cygwin apps are started simultaneously and this is the
first execution of non-cygwin apps in the pty, these occasionally
hang up. The cause is the race issue between term_has_pcon_cap(),
reset_switch_to_pcon() and setup_pseudoconsole(). This patch fixes
the issue.
- 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.
- 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.
- After commit bb428520, there has been the disadvantage:
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.
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 buffer used in get_console_process_id(), introduced by commit
72770148, is too large and ERROR_NOT_ENOUGH_MEMORY occurs in Win7.
Therefore, the buffer size has been reduced.
- cat exits immediately in the following senario.
1) Execute env CYGWIN=disable_pcon script
2) Execute cmd.exe
3) Execute cat in cmd.exe.
This is caused by setting input_available_event for the pipe for
non-cygwin app. This patch fixes the issue.
- 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.
- The workaround for rlwrap introduced by commit 8199b0cc does not
take effect for rlwrap 0.40 or later. This patch add a workaround
for rlwrap 0.40 or later as well.
- Previous workaround has a problem that screen is distorted if up
arrow key is pressed at the first line after running "rlwrap cmd".
This patch fixes the issue.
- Previous code to read response for CSI6n allows invalid response
such as "CSI Pl; Pc H" other than correct response "CSI Pl; Pc R".
With this patch, the response is checked more strictly.
- Sometimes timeout period in term_has_pcon_cap() may not be enough
when the machine slows down for some reason. This patch eases the
issue. In the new code, effective timeout period is expected to be
extended as a result due to slowing-down the wait loop as well when
the machine gets into busy.
- If vim is executed in WSL in mintty, some garbage string caused
by "OSC Ps;? BEL/ST" will be shown in some situations. This patch
fixes the issue by removing "OSC Ps;? BEL/ST" from pseudo console
output.
- Calling ResizePseudoConsole() generates some escape sequences.
Due to this behaviour, if the output of non-cygwin app is piped
to less, screen is sometimes distorted when the screen is resized.
With this patch, ResizePseudoConsole() is not called if stdout is
redirected.
- If output of non-cygwin process is piped to cygwin process, such
as less, the non-cygwin process sometimes fails to start and hangs.
This patch fixes the issue.
- Charset conversion for UTF-7, ISO-2022 and ISCII, which are not
supported in cygwin, does not work properly as a result. At the
expense of the above, the code has been simplified a bit.
- If pseudo console is disabled, non-cygwin apps do not detect
console device. In this case, some apps output UTF-8 regardless
of the locale setting. At least git-for-windows, rust-based apps
and node.js do that. This patch provides backward compatibility
as default behaviour by setting console codepage to the charset of
the locale. Even in the cases above, garbled output is prevented
with this patch in most cases because mintty uses UTF-8 by default.
I beleave this is not really a problem in cygwin side but that in
app side, however, some users complain about garbled output with
existing apps in MSYS2 (which is based on cygwin) in which pseudo
console is disabled by default.
Takashi Yano
Ken Brown
Thomas Wolff
Corinna Vinschen
Takashi Yano via Cygwin-patches