The expression computing the next-less-power of 2 for the next write
when the pipe buffer is getting filled up allows negative shift values.
This works on Intel CPUs because the shift expression only evaluates the
5 LSBs, but it's undefined behaviour per the C standard. Use the
correct expression to get a positive shift value.
Fixes: 170e6badb621 ("Cygwin: pipe: improve writing when pipe buffer is almost full")
Reported-by: Takashi Yano <takashi.yano@nifty.ne.jp>
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
If a cygwin app is executed from a non-cygwin app and the cygwin
app exits, the read pipe remains in the non-blocking mode because
of the commit fc691d0246b9. Due to this behaviour, the non-cygwin
app cannot read the pipe correctly after that. Similarly, if a
non-cygwin app is executed from a cygwin app and the non-cygwin
app exits, the read pipe remains in the blocking mode. With this
patch, the blocking mode of the read pipe is stored into a variable
was_blocking_read_pipe on set_pipe_non_blocking() when the cygwin
app starts and restored on close(). In addition, the pipe mode is
set to non-blocking mode in raw_read() if the mode is blocking
mode by referring the variable is_blocking_read_pipe as well.
is_blocking_read_pipe is a member of fhandler_pipe class and is set
by set_pipe_non_blocking(), so if other process sets the pipe mode
to blocking mode, the current process cannot know the pipe is
blocking mode. Therefore, is_blocking_read_pipe is also set on the
signal __SIGNONCYGCHLD, which is sent to the process group when
non-cygwin app is started.
Addresses: https://github.com/git-for-windows/git/issues/5115
Fixes: fc691d0246b9 ("Cygwin: pipe: Make sure to set read pipe non-blocking for cygwin apps.");
Reported-by: isaacag, Johannes Schindelin <Johannes.Schindelin@gmx.de>
Reviewed-by: Corinna Vinschen <corinna@vinschen.de>, Ken Brown <kbrown@cornell.edu>
Signed-off-by: Takashi Yano <takashi.yano@nifty.ne.jp>
After the commit 7f3c22532577, writing to pipe extremely slows down.
This is because cygwait(select_sem, 10, cw_cancel) is called even
when write operation is already completed. With this patch, the
cygwait() is called only if the write operation is not completed.
Addresses: https://cygwin.com/pipermail/cygwin/2024-August/256398.html
Fixes: 7f3c22532577 ("Cygwin: pipe: handle signals explicitely in raw_write")
Reported-by: Jim Reisert AD1C <jjreisert@alum.mit.edu>
Reviewed-by: Corinna Vinschen <corinna@vinschen.de>
Signed-off-by: Takashi Yano <takashi.yano@nifty.ne.jp>
(cherry picked from commit f78009cb1ccf84cc343cf2441c76196461d87532)
If a nonblocking write requires short writes, just try it once
as in the blocking case. After all, we are nonblocking, so
don't loop unnecessarily.
Fixes: 170e6badb621 ("Cygwin: pipe: improve writing when pipe buffer is almost full")
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
There's no reason to overwrite len1 with align if they are the same value.
Fixes: 170e6badb621 ("Cygwin: pipe: improve writing when pipe buffer is almost full")
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
So far fhandler_pipe_fifo::raw_write always returns -1/EINTR
if a signal arrived. Linux does not do that if there's still
space left in the pipe buffer.
The Linux buffer handling can't be emulated by Cygwin, but we
can do something similar which makes it much more likely to still
write successfully even if the buffer is almost full.
Utilize pipe_data_available to return valid pipe buffer usage
to raw_write, allowing a more sophisticated way to fill the
buffer while maintaining comaptibility with non-Cygwin pipes.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
The simple cygwait call in fhandler_pipe_fifo::raw_write doesn't
take the SA_RESTART setting into account. Move handling the
signal into raw_write.
Fixes: 4b25687ea3ee2 ("Cygwin: fhandler_pipe: add raw_read and raw_write")
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
If pipe reader is a non-cygwin app first, and cygwin process reads
the same pipe after that, the pipe has been set to bclocking mode
for the cygwin app. However, the commit 9e4d308cd592 assumes the
pipe for cygwin process always is non-blocking mode. With this patch,
the pipe mode is reset to non-blocking when cygwin app is started.
Addresses: https://cygwin.com/pipermail/cygwin/2024-March/255644.html
Fixes: 9e4d308cd592 ("Cygwin: pipe: Adopt FILE_SYNCHRONOUS_IO_NONALERT flag for read pipe.")
Reported-by: wh <wh9692@protonmail.com>
Reviewed-by: Corinna Vinschen <corinna@vinschen.de>
Signed-off-by: Takashi Yano <takashi.yano@nifty.ne.jp>
Non-cygwin app may call ReadFile() for empty pipe, which makes
NtQueryObject() for ObjectNameInformation block in fhandler_pipe::
get_query_hdl_per_process. Therefore, do not to try to get query_hdl
for non-cygwin apps.
Addresses: https://github.com/msys2/msys2-runtime/issues/202
Fixes: b531d6b06eeb ("Cygwin: pipe: Introduce temporary query_hdl.")
Reported-by: Alisa Sireneva, Johannes Schindelin <Johannes.Schindelin@gmx.de>
Reviewed-by: Corinna Vinschen <corinna@vinschen.de>
Signed-off-by: Takashi Yano <takashi.yano@nifty.ne.jp>
also, take mode flags parameter instead of just a bool.
Introduce __FALLOC_FL_TRUNCATE mode flag as internal flag to
indictae being called from ftruncate(2).
This is in preparation of an upcoming change introducing the
Linx-specific fallocate(2) call.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
https://cygwin.com/pipermail/cygwin/2022-December/252628.html
After the commit 9e4d308cd592, the performance of read from non-cygwin
pipe has been degraded. This is because select_sem mechanism does not
work for non-cygwin pipe. This patch fixes the issue.
Fixes: 9e4d308cd592 ("Cygwin: pipe: Adopt FILE_SYNCHRONOUS_IO_NONALERT
flag for read pipe.")
Reported-by: tryandbuy <tryandbuy@proton.me>
Reviewed-by: Corinna Vinschen <corinna@vinschen.de>
Signed-off-by: Takashi Yano <takashi.yano@nifty.ne.jp>
Only required for Windows 7.
This allows to remove fhandler_pipe::get_query_hdl_per_system(),
too.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
