Otherwise big stacks have a higher probability to collide with
randomized PEBs and TEBs after fork.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
Unfortunately Windows doesn't understand WSL symlinks,
despite being a really easy job. NT functions trying
to access paths traversing WSL symlinks return the status
code STATUS_IO_REPARSE_TAG_NOT_HANDLED. Handle this
status code same as STATUS_OBJECT_PATH_NOT_FOUND in
symlink_info::check to align behaviour to traversing
paths with other non-NTFS type symlinks.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
The descriptions of symlink handling are a bit dated, so
revamp them and add the new WSL symlink type.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
WSL symlinks are reparse points containing a POSIX path in UTF-8.
On filesystems supporting reparse points, use this symlink type.
On other filesystems, or in case of error, fall back to the good
old plain SYSTEM file.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
Commit 4a36897af3 allowed to convert /mnt/<drive> path
prefixes to Cygwin cygdrive prefixes on the fly. However,
the patch neglected WSL symlinks pointing to the /mnt
directory. Rearrange path conversion so /mnt is converted
to the cygdrive prefix path itself.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
Treat WSL symlinks just like other symlinks. Convert
absolute paths pointing to Windows drives via
/mnt/<driveletter> to Windows-style paths <driveletter>:
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
This reverts commit 082f2513c7.
Turns out, Linux as well as BSD really only wait for the smaller
number, MIN or # of requested bytes.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
Per termios, read waits for MIN chars even if the number of requested
bytes is less. This requires to add WaitCommEvent to wait non-busily
for MIN chars prior to calling ReadFile, so, reintroduce it.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
Sharing the OVERLAPPED struct and event object in there between
read and select calls in the fhandler might have been a nice
optimization way back when, but it is a dangerous, not thread-safe
approach. Fix this by creating per-fhandler, per-call OVERLAPPED
structs and event objects on demand.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
- make sure event object is reset
- set read_ready to true if WaitCommEvent returns success
- improve debugging
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
tcsetattr checks if the VTIME and VMIN values changed and only
calls SetCommTimeouts if so. That's a problem if tcsetattr
is supposed to set VTIME and VIMN to 0, because these are the
start values anyway. But this requires to set ReadIntervalTimeout
to MAXDWORD, which just doesn't happen.
Fix this by dropping the over-optimization of checking the old
values before calling SetCommTimeouts,
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
After changing the type of fhandler_serial::vtime_ to cc_t, vtime_
must be stored in 10s of seconds, not in milliseconds.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
Get rid of WaitCommEvent and using overlapped_armed to share the
same overlapped operation between read and select. Rather, make
sure to cancel the overlapped IO before leaving any of these functions.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
- Datatypes were incorrect, especially vmin_ and vtime_.
Change them to cc_t, as in user space.
- Error checking had a gap or two. Debug output used the
wrong formatting.
- Don't use ev member for ClearCommError and WaitCommEvent.
Both returned values are different (error value vs. event
code). The values are not used elsewhere so it doesn't make
sense to store them in the object. Therefore, drop ev member.
- Some variable names were not very helpful. Especially using
n as lpNumberOfBytesTransferred from GetOverlappedResult and
then actually printing it as if it makes sense was quite
puzzeling.
- Rework the loop and the definition of minchars so that it
still makes sense when looping.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
- Don't use ev member for ClearCommError and WaitCommEvent.
Both returned values are different (error value vs. event
code). The values are not used elsewhere so it doesn't make
sense to store them in the object.
- Drop local variable ready which is used inconsequentially.
- Since WFSO already waits 10 ms, don't wait again if no char
is in the inbound queue.
- Avoid else if chains.
- Only print one line of debug output on error.
- Drop overlapped_armed < 0 check. This value is only set in
fhandler_serial::raw_read if VTIME > 0, and even then it's only
set to be immediately reset to 0 before calling ReadFile. So
overlapped_armed is never actually < 0 when calling select.
- Fix a screwed up statement order.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
Passing a pointer to a local variable to WriteConsoleA is
not actually needed if we're not going to do anything with
what WriteConsoleA would put in there.
For the wpbuf class the pointer argument was made optional,
so it can be just left out; other call places now pass a
NULL pointer instead. The local variables `wn' and `n'
are no unused, so they go away.
Replace direct access to a pair of co-dependent variables
by calls to methods of a class that encapsulates their relation.
Also replace C #define by C++ class constant.
- In xterm compatible mode, "ESC 7" and "ESC 8" do not work properly
in the senario:
1) Execute /bin/ls /bin to fill screen.
2) Sned CSI?1049h to alternate screen.
3) Reduce window size.
4) Send CSI?1049l to resume screen.
5) Send "ESC 7" and "ESC 8".
After sending "ESC 8", the cursor goes to incorrect position. This
patch adds a workaround for this issue.
- This patch fixes the issue that xterm compatible mode for input
is not correctly set/unset in some situation such as:
1) cat is stopped by ctrl-c.
2) The window size is changed in less.
In case 1), request_xterm_mode_input(true) is called in read(),
however, cat is stopped without request_xterm_mode_input(false).
In case 2), less uses longjmp in signal handler, therefore,
corresponding request_xterm_mode_input(false) is not called if
the SIGWINCH signal is sent within read(). With this patch,
InterlockedExchange() is used instead of InterlockedIncrement/
Decrement().
So far ioctl(TIOCINQ) could end up returning -1 with errno set to EINVAL
if a non-zero device error mask has been returned by ClearCommError.
This doesn't reflect Linux behaviour, which always returns the number of
chars in the inbound queue, independent of any I/O error condition.
EINVAL was a pretty weird error code to use in this scenario, too.
Fix this by dropping all checking for device errors in the TIOCINQ
case. Just return the number of chars in the inbound queue.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
- This patch makes some detailed behaviour of ESC sequences such as
"CSI Ps L" (IL), "CSI Ps M" (DL) and "ESC M" (RI) in xterm mode
match with real xterm.
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>
Aligning the stack pointer using an asm statement isn't any longer
supported. gcc-9.2.0 generates the following warning:
init.cc:33:46: error: listing the stack pointer register '%esp'
in a clobber list is deprecated [-Werror=deprecated]
[...]
init.cc:33:46: note: the value of the stack pointer after an
'asm' statement must be the same as it was before the statement
Replace the asm expression with the gcc function attribute
`force_align_arg_pointer'. This aligns the stack exactly as
required.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
reopen_shmem is accidentally called on the parent fhandler
rather than the child fhandler, and it's called too early.
Make sure to call it on the child and only after its shmem_handle
is valid.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
Update dumper for bfd API changes in binutils 2.34
libbfd doesn't guarantee API stability, so we've just been lucky this
hasn't broken more often.
See binutils commit fd361982.
- In Win10 upto 1809, xterm compatible mode does not have REP
escape sequence which terminfo declares. This patch adds support
for "CSI Ps b" (REP). With this patch, bvi (binary editor) works
normally in Win10 1809. Also, xterm compatible mode does not have
"CSI Pm `" (HPA), "CSI Pm a" (HPR) and "CSI Ps e" (VPR). However,
they do not appear to be declared by terminfo. Therefore, these
have been pending.
- Cygwin console with xterm compatible mode causes problem reported
in https://www.cygwin.com/ml/cygwin-patches/2020-q1/msg00212.html
if background/foreground colors are set to gray/black respectively
in Win10 1903/1909. This is caused by "CSI Ps L" (IL), "CSI Ps M"
(DL) and "ESC M" (RI) control sequences which are broken. This
patch adds a workaround for the issue.
The helper function ttynam creates a tty name by using sprintf wrongly
on a pretty short buffer. The foramt string only specifies a minimum
field length, not a maximum field length, so gcc-9.2.0 complains:
ps.cc:101:23: warning: 'sprintf' may write a terminating nul past the
end of the destination [-Wformat-overflow=]
Fix this thoroughly by specifying a maximum field width as well as by
using snprintf with a fixed buffer length. Also, drop using a static
buffer in favor of using a buffer in the caller.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
...from structs used for data exchange between clients and cygserver.
All of the structs have the same size and member offsets, packed or
unpacked. Keeping the packed attribute results in ominous warnings
from gcc-9.2.0:
cygserver.cc:259:10: warning: taking address of packed member of
'client_request_attach_tty::request_attach_tty' may result in an
unaligned pointer value [-Waddress-of-packed-member]
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
gcc-9.2.0 has an execve builtin which uses the nothrow attribute.
This results in an error when aliasing execve to _execve for newlib:
exec.cc:88:23: error: 'int _execve(const char*, char* const*, char*
const*)' specifies less restrictive attribute than its target
'int execve(const char*, char* const*, char* const*)': 'nothrow'
[-Werror=missing-attributes]
88 | EXPORT_ALIAS (execve, _execve) /* For newlib */
Add the -fno-builtin-execve CFLAGS when building exec.o to override
the gcc builtin.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
The variable returning the overrun count from the tracker object after
disarming the overrun counter was not correctly initialized. For some
reason this has only been noticed by gcc-9.2.0, not by the formerly used
gcc-7.4.0.
This problem should not have had any runtime impact. The method
timer_tracker::disarm_overrun_event is supposed to be called in
lock-step with timer_tracker::arm_overrun_event, which in turn
results in the variable getting a valid value.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
linux 4.6 x86/cpu: Add advanced power management bits
Bit 11 of CPUID 8000_0007 edx is processor feedback interface.
Bit 12 of CPUID 8000_0007 edx is accumulated power.
Print proper names in /proc/cpuinfo
[missed enabling this 2016 change during previous major cpuinfo update
as no power related changes were made to the Linux files since then]
- Accessing shared_console_info before initialization causes access
violation because it is a NULL pointer. The cause of the problem
reported in https://cygwin.com/ml/cygwin/2020-02/msg00197.html is
this NULL pointer access in request_xterm_mode_output() when it is
called from close(). This patch makes sure that shared_console_info
is not NULL before calling request_xterm_mode_output().
Added in Linux 5.6:
Check FSRM and use REP MOVSB for short copies on systems that have it.
>From the Intel Optimization Reference Manual:
3.7.6.1 Fast Short REP MOVSB
Beginning with processors based on Ice Lake Client microarchitecture,
REP MOVSB performance is enhanced with string lengths up to 128 bytes.
Support for fast-short REP MOVSB is indicated by the CPUID feature flag:
CPUID [EAX=7H, ECX=0H).EDX.FAST_SHORT_REP_MOVSB[bit 4] = 1.
There is no change in the REP STOS performance.
A NUL byte in the output stream got accidentally not handled as IGN char
in xterm console mode. The internal mbtowc conversion doesn't handle
embedded NUL values gracefully, it always stops converting at NUL bytes.
This broke the output of strings with embedded NUL bytes.
Fix this by always skipping IGN chars in the "normal char output loop"
and make sure not to move the cursor one position to the right, as in
legacy console mode.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
NSIG is a deprecated symbol only visible under MISC visibility.
_NSIG is used widely instead, and on most systems NSIG is
defined in terms of _NSIG.
Follow suit: Change NSIG to _NSIG throughout and change visiblity
of NSIG to be defined only in __MISC_VISIBLE case.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
- If two cygwin programs are executed simultaneousley with pipes
in cmd.exe, xterm compatible mode is accidentally disabled by
the process which ends first. After that, escape sequences are
not handled correctly in the other app. This is the problem 2
reported in https://cygwin.com/ml/cygwin/2020-02/msg00116.html.
This patch fixes the issue. This patch also fixes the problem 3.
For these issues, the timing of setting and unsetting xterm
compatible mode is changed. For read, xterm compatible mode is
enabled only within read() or select() functions. For write, it
is enabled every time write() is called, and restored on close().
- 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().
- With this patch, foreground color and background color are allowed
to be set simultaneously by 24 bit color escape sequence such as
ESC[38;2;0;0;255;48;2;128;128;0m in legacy console mode.
When fhandler_base::fstat_helper is called, the handle h returned by
get_stat_handle() should be pc.handle() and should be safe to use for
getting the file information. Previously, the call to
get_file_attribute() for FIFOs set the first argument to NULL instead
of h, thereby forcing the file to be opened for fetching the security
descriptor in get_file_sd().
Make fhandler_socket_local::dup and fhandler_socket_local::fcntl (a
new method) call fhandler_base::dup and fhandler_base::fcntl if O_PATH
is set.
We're viewing the socket as a disk file here, but there's no need to
implement the actions of fhandler_disk_file::dup and
fhandler_disk_file::fcntl, which do nothing useful in this case beyond
what the fhandler_base methods do. (The extra actions are only useful
when I/O is going to be done on the file.)
If O_PATH is set, then the fhandler_socket_local object has a handle
that can be used for getting the statvfs information. Use it by
calling fhandler_base::fstatvfs_by_handle. Without this change,
fhandler_disk_file::fstatfvs would be called on a new fhandler_disk
object, which would then have to be opened.
If an AF_LOCAL socket is opened with O_PATH, all socket system calls
that take a file descriptor argument fail on the resulting descriptor.
Make sure that errno is set as on Linux for those calls that are
implemented on Linux. In almost all cases it is ENOTSOCK. There are
two exceptions:
- sockatatmark(3); errno is EBADF.
- bindresvport(3); errno is EAFNOSUPPORT if the second argument sin
(of type struct sockaddr_in *) is non-NULL and satisfies
sin->sin_family == AF_INET.
Finally, there are two BSD socket system calls implemented on Cygwin
but not Linux: getpeereid(3) and bindresvport_sa(3). Set errno to
ENOTSOCK for these for consistency with the majority of the other
calls.
If that flag is not set, or if an attempt is made to open a different
type of socket, the errno is now EOPNOTSUPP instead of ENXIO. This is
consistent with POSIX, starting with the 2016 edition. Earlier
editions were silent on this issue.
Opening is done in a (new) fhandler_socket_local::open method by
calling fhandler_base::open_fs.
Also add a corresponding fhandler_socket_local::close method.
This edits licenses held by Berkeley and NetBSD, both of which
have removed the advertising requirement from their licenses.
Signed-off-by: Keith Packard <keithp@keithp.com>
This option has been disabled long ago and nobody missed it.
Removing drops a bit of unneeded code
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
If O_PATH is set, then the fhandler_fifo object has a handle that can
be used for getting the statvfs information. Use it by calling
fhandler_base::fstatvfs_by_handle. Before this change,
fhandler_disk_file::fstatfvs was called on a new fhandler_disk_file
object, which would then have to be opened.
Define a new method fhandler_base::fstatvfs_by_handle, extracted from
fhandler_disk_file::fstatvfs, which gets the statvfs information when
a handle is available.
This will be used in future commits for special files that have been
opened with O_PATH.
Treat a special file opened with O_PATH the same as a regular file,
i.e., use its handle to get the stat information.
Before this change, fstat_fs opened the file a second time, with the
wrong flags and without closing the existing handle. A side effect
was to change the openflags of the file, possibly causing further
system calls to fail.
Currently this change only affects FIFOs, but it will affect
AF_LOCAL/AF_UNIX sockets too once they support O_PATH.
mknod32 actually creates a path_conv, just to call mknod_worker
with a win32 path. This doesn't only require to create path_conv
twice, it also breaks permissions on filesystems supporting ACLs.
Fix this by passing the path_conv created in the caller down to
symlink_worker. Also, while at it, simplify the handling of trailing
slashes and move it out of symlink_worker. Especially use the
new PC_SYM_NOFOLLOW_DIR flag to avoid fiddeling with creating
a new path copy without the trailing slash.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
Usually a trailing slash requires to follow an existing symlink,
even with PC_SYM_NOFOLLOW. The reason is that "foo/" is equivalent
to "foo/." so the symlink is in fact not the last path component,
"." is. This is default for almost all scenarios.
PC_SYM_NOFOLLOW_DIR now allows the caller to request not to
follow the symlink even if a trailing slash is given. This can
be used in callers to perform certain functions Linux-compatible.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
- 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.
If the O_PATH flag is set, fhandler_fifo::open now simply calls
fhandler_base::open_fs.
The previous attempt to handle O_PATH in commit aa55d22c, "Cygwin:
honor the O_PATH flag when opening a FIFO", fixed a hang but otherwise
didn't do anything useful.
If O_PATH is set in the flags argument of
fhandler_base::device_access_denied, return false. No
read/write/execute access should be required in this case.
Previously, the call to device_access_denied in open(2) would lead to
an attempt to open the file with read access even if the O_PATH flag
was set.
rdpru flag is cpuid xfn 80000008 ebx bit 4 added in linux 5.5;
see AMD64 Architecture Programmer's Manual Volume 3:
General-Purpose and System Instructions
https://www.amd.com/system/files/TechDocs/24594.pdf#page=329
and elsewhere in that document
- 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.
Following Linux, allow the pathname argument to be an empty string if
the AT_EMPTY_PATH flag is specified. In this case the dirfd argument
can refer to any type of file, not just a directory, and the call
operates on that file. In particular, dirfd can refer to a symlink
that was opened with O_PATH | O_NOFOLLOW.
Following Linux, allow the pathname argument to be an empty string,
provided the dirfd argument refers to a symlink opened with
O_PATH | O_NOFOLLOW. The readlinkat call then operates on that
symlink.
Commit 283cb372, "Cygwin: normalize_win32_path: improve error
checking", required a prefix '\\?\' or '\??\' in the source path to be
followed by 'UNC\' or 'X:\', where X is a drive letter. That was too
restrictive, since it disallowed the paths '\\?\X: and '\??\X:'. This
caused problems when a user tried to use the root of a drive as the
Cygwin installation root, as reported here:
https://cygwin.com/ml/cygwin/2020-01/msg00111.html
Modify the requirement so that '\??\X:' and '\\?\X:' are now allowed
as source paths, without a trailing backslash.
- In octave gui, sometimes state mismatch between real pty state
and state variable occurs. For example, this occurs when 'ls'
command is executed in octave gui. This patch fixes the issue.
- 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.
- The console with 24bit color support has a problem that console
mode is changed if cygwin process is executed in cmd.exe which
started in cygwin shell. For example, cursor keys become not
working if bash -> cmd -> true are executed in this order.
This patch fixes the issue.
- In Win10 1809, the cursor position sometimes goes out of screen
by clear command in console. This seems to be caused by escape
sequence CSI3J (ESC[3J). This happens only for 1809. This patch
is a workaround for the issue.
- 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.
- The slowing down issue of X11 forwarding using ssh -Y, reported
in https://www.cygwin.com/ml/cygwin/2019-12/msg00295.html,
is due to the change of select() code for pty in the commit
915fcd0ae8. cygthread::detach()
takes at most about 10msec because Sleep() is used in the thread.
For this issue, this patch uses cygwait() instead of Sleep() and
introduces an event to abort the wait. For not only pty, but pipe
and fifo also have the same problem potentially, so this patch
applies same strategy to them as well.
Though our implementation of cpu sets doesn't need it, software from
Linux environments expects this definition to be present. It's
documented on the Linux CPU_SET(3) man page but was left out due to
oversight.
Addresses https://cygwin.com/ml/cygwin/2019-12/msg00248.html
Add that flag to the pipe type argument when creating the Windows
named pipe. And add a definition of that flag to ntdll.h (copied from
/usr/include/w32api/ddk/ntifs.h).
- 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.
Both functions were introduce with Windows 7 only, so we need to
autoload them for the sake of Vista/2008.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
On certain error conditions there is a code snippet that checks
whether the last component of the path has a trailing dot or space or
a leading space. Skip this check if the last component is empty,
i.e., if the path ends with a backslash. This avoids an assertion
failure if the trailing backslash is the only backslash in the path,
as is the case for a DOS drive 'X:\'.
Addresses: https://cygwin.com/ml/cygwin/2019-12/msg00016.html
- 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.
fhandler_console::create_invisible_console_workaround() does not use the
lpApplicationName parameter and neglects to quote its command name on
lpCommandLine in the call to CreateProcessW.
Given CreateProcessW's brain-dead method to evaluate the application
path given on the command line, this opens up a security problem if
Cygwin is installed into a path with spaces in it.
Fix this by using the lpApplicationName parameter and quoting of the
application path in the lpCommandLine parameter (used as argv[0] in
the called console helper.
For extended paranoia, make the argument string array big enough to
fit full 64 bit pointer values into it. Handles usually only use
the lower 32 bit, but better safe than sorry.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
FH_CONS_MAX should refelect the fact that we allow 128 consoles, even if
it's unused.
Suggested-by: Achim Gratz <Stromeko@nexgo.de>
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
Commit 5a0f2c00aa "Cygwin: fork/exec: fix child process permissions"
removed the PROCESS_DUP_HANDLE handle permission of the parent process
handle in the child to avoid a security problem.
It turned out that this broke the following scenario: If a process forks
and then the parent execs, the child loses the ability to register the
parent's death. To wit, after the parent died the child process does
not set its own PPID to 1 anymore.
The current exec mechanism copies required handle values (handles to
keep contact to the child processes) into the child_info for the
about-to-be-exec'ed process. The exec'ed process is supposed to
duplicate these handles. This fails, given that we don't allow the
exec'ed process PROCESS_DUP_HANDLE access to the exec'ing process since
commit 5a0f2c00aa.
The fix is to avoid the DuplicateHandle calls in the exec'ed process.
This patch sets the affected handles to "inheritable" in the exec'ing
process at exec time. The exec'ed process just copies the handle values
and resets handle inheritance to "non-inheritable". The exec'ing
process doesn't have to reset handle inheritance, it exits after setting
up the exec'ed process anyway.
Testcase: $ ssh-agent /bin/sleep 3
ssh-agent forks and the parent exec's sleep. After sleep exits, `ps'
should show ssh-agent to have PPID 1, and eventually ssh-agent exits.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
Call find_exec with the FE_NNF flag to enforce a NULL return when the
executable isn't found in $PATH. Convert NULL to "". This aligns
spawnvp and spawnvpe with execvp and execvpe.
If the directory name has the form 'x:' followed by one or more
slashes or backslashes, and if there's at least one backslash, assume
that the user is referring to 'x:\', the root directory of drive x,
and don't strip the backslash.
Previously all trailing slashes and backslashes were stripped, and the
name was treated as a relative file name containing a literal colon.
Addresses https://cygwin.com/ml/cygwin/2019-08/msg00334.html.
Add feature test print macro that makes feature, bit, and flag text
comparison and checking easier. Handle as common former Intel only
feature flags also supported on AMD. Change order and some flag names
to agree with current Linux.
If the source path starts with the Win32 long path prefix '\\?\' or
the NT object directory prefix '\??\', require the prefix to be
followed by 'UNC\' or '<drive letter>:\'. Otherwise return EINVAL.
This fixes the assertion failure in symlink_info::check that was
reported here:
https://cygwin.com/ml/cygwin/2019-09/msg00228.html
That assertion failure was caused by normalize_win32_path returning a
path with no backslashes when the source path was '\\?\DRIVE'.
If the last component of the directory name is a symlink followed by a
slash, rmdir now fails, following Linux but not POSIX, even if the
symlink resolves to an existing empty directory.
mkdir was similarly changed in 2009 in commit
52dba6a5c4. Modify a comment to clarify
the purpose of that commit.
Addresses https://cygwin.com/ml/cygwin/2019-09/msg00221.html.
Prior to commit b0717aae, path_conv::check had the following code:
if (strncmp (path, "\\\\.\\", 4))
{
/* Windows ignores trailing dots and spaces in the last path
component, and ignores exactly one trailing dot in inner
path components. */
char *tail = NULL;
[...]
if (!tail || tail == path)
/* nothing */;
else if (tail[-1] != '\\')
{
*tail = '\0';
[...]
}
Commit b0717aae0 intended to disable this code, but it inadvertently
disabled only part of it. In particular, the declaration of the local
tail variable was in the disabled code, but the following remained:
if (!tail || tail == path)
/* nothing */;
else if (tail[-1] != '\\')
{
*tail = '\0';
[...]
}
[A later commit removed the disabled code.]
The tail variable here points into a string different from path,
causing that string to be truncated under some circumstances. See
https://cygwin.com/ml/cygwin/2019-09/msg00001.html
for more details.
This commit fixes the problem by removing the leftover code
that was intended to be removed in b0717aae.
- The autoload feature is used rather than GetModuleHandle(),
GetProcAddress() for CreatePseudoConsole(), ResizePseudoConsole()
and ClosePseudoConsole().
- Since calling system __loadlocale() caused execution error,
PTY used its own NLS function. The cause of the error has been
found, the corresponding code has been rewritten using system
function.
The CPU_SET macros defined in Cygwin's include/sys/cpuset.h must not
be visible in an application's namespace unless _GNU_SOURCE has been
#defined. Internally this means wrapping them in #if __GNU_VISIBLE.
- In non-canonical mode, cygwin console returned only one character
even if several keys are typed before read() called. This patch
fixes this behaviour.
- Previously, input and output pipes were switched together between
the traditional pty and the pseudo console. However, for example,
if stdin is redirected to another device, it is better to leave
input pipe traditional pty side even for non-cygwin program. This
patch realizes such behaviour.
- If screen alternated while pseudo console switching, it sometimes
failed. This might happen when the output of the non-cygwin program
is piped to less. This patch fixes this issue.
- When the I/O pipe is switched to the pseudo console side, the
behaviour of Ctrl-C was unstable. This rarely happens, however,
for example, shell sometimes crashes by Ctrl-C in that situation.
Furthermore, Ctrl-C was ignored if output of non-cygwin program
is redirected to pipe. This patch fixes these issues.
- Forcibly attach to pseudo console in advance so that the error
messages by system_printf() are displayed to screen reliably.
This is needed when stdout is redirected to another pty. In this
case, process has two ptys opened. However, process can attach
to only one console. So it is necessary to change console attached.
- PTY with pseudo console support sitll has problem which potentially
cause state mismatch between state variable and real console state.
This patch fixes this issue.
- select() did not work correctly when both read and except are
polled simultaneously for the same fd and the r/w pipe is switched
to pseudo console side. This patch fixes this isseu.
- Pseudo console support introduced by commit
169d65a577 shows garbage ^[[H^[[J in
some of emacs screens. These screens do not handle ANSI escape
sequences. Therefore, clear screen is disabled on these screens.
- Pseudo console support introduced by commit
169d65a577 sometimes cause random
crash or freeze by pressing ^C while cygwin and non-cygwin
processes are executed simultaneously in the same pty. This
patch is a workaround for this issue.
- API hook used for pseudo console support causes slow down.
This patch limits API hook to only program which is linked
with the corresponding APIs. Normal cygwin program is not
linked with such APIs (such as WriteFile, etc...) directly,
therefore, no slow down occurs. However, console access by
cygwin.dll itself cannot switch the r/w pipe to pseudo console
side. Therefore, the code to switch it forcely to pseudo
console side is added to smallprint.cc and strace.cc.
- Pseudo console support introduced by commit
169d65a577 has some bugs which
cause mismatch between state variables and real pseudo console
state regarding console attaching and r/w pipe switching. This
patch fixes this issue by redesigning the state management.
- PTY uses Win32 API hook for pseudo console suppot. The function
hook_api() is used for this purpose and defined in fhandler_tty.cc
previously. This patch moves it into hookapi.cc.
- Support pseudo console in PTY. Pseudo console is a new feature
in Windows 10 1809, which provides console APIs on virtual
terminal. With this patch, native console applications can work
in PTYs such as mintty, ssh, gnu screen or tmux.
Rather than waiting for signalfd_select_wait in a thread, which is racy,
create a global event "my_pendingsigs_evt" which is set and reset by
wait_sig depending only on the fact if blocked signals are pending or not.
This in turn allows to WFMO on this event in select as soon as signalfds
are present in the read descriptor set. Select's peek and verify
will then check if one of the present signalfds is affected.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
Borrow a trick from strace to lessen occurrences of "??? => ???" in ldd
output. Specifically, if the module name isn't found in the usual place
in the mapped image, use the file handle we have to look up the name.
On sigwaitinfo or reading from a signalfd, signal processing sets up
signal handling via sigdelayed even if the handler address is NULL.
This doesn't have any impact on sigwaitinfo scenarios (or at least, I
wasn't able to come up with a reproducer) but it breaks signalfd
scenarios, where eventually a call to call_signal_handler from
sigdelayed will try to call the NULL function.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
- If screen is alternated on console, cursor position is not restored
correctly in the case of xterm compatible mode is enabled. For example,
the shell prompt is shown at incorrect position after using vim.
This patch fixes this problem.
- The horizontal tab positions are broken after resizing console window.
This seems to be a bug of xterm compatible mode of windows console.
This workaround fixes this problem.
The default implementation of the fenv.h methods return
-EOPNOTSUP. Some of these have implementations appropriate
for soft-float.
The intention of the new fenv.h is that it be portable
and that architectures provide their own implementation
of sys/fenv.h.
This avoids collisions of shmat maps with Windows own datastructures
when allocating top-down.
This patch moves the mmap_allocator class definition into its
own files and just uses it from mmap and shmat.
Adding default winvar 'PATH=C:\cygwin64\binZ' to an environment that is
already allocated for 'SYSTEMROOT=ZWINDIR=Z', we need to count that
trailing (Z)ero as well. Otherwise we trigger this assertion failure:
$ /bin/env -i SYSTEMROOT= WINDIR= /bin/env
assertion "(s - envblock) <= tl" failed: file "/home/corinna/src/cygwin/cygwin-3.0.7/cygwin-3.0.7-1.x86_64/src/newlib-cygwin/winsup/cygwin/environ.cc", line 1302, function: char** build_env(const char* const*, WCHAR*&, int&, bool, HANDLE)
Aborted (core dumped)
When the exec family of functions is called for a script-like
file, the av::setup function handles the exec[vl]p case as
well. The execve case for files not starting with a she-bang
is handled first by returning ENOEXEC. Only after that, the
file's executability is checked.
This leads to the problem that ENOEXEC is returned for non-executable
files as well. A calling shell interprets this as a file it should try
to run as script. This is not desired for non-executable files.
Fix this problem by checking the file for executability first. Only
after that, follow the other potential code paths.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
This patch supplies an implementation of the CPU_SET(3) processor
affinity macros as documented on the relevant Linux man page.
There is a mostly superset implementation of cpusets under newlib's
libc/sys/RTEMS/include/sys that has Linux and FreeBSD compatibility
and is built on top of FreeBSD bitsets. This Cygwin implementation
and the RTEMS one could be combined if desired at some future point.
Do not attach to the child before it was successfully initialized, or we
would need more sophisticated cleanup on child initialization failure,
like suppressing SIGCHILD delivery with multiple threads ("waitproc")
involved.
Improves "Cygwin: fork: Remember child not before success.",
commit f03ea8e1c5, which leads to fork
problems if cygserver is running:
https://cygwin.com/ml/cygwin-patches/2019-q2/msg00155.html
During fork, the child process requires the process table to be
initialized for fixup_shms_after_fork, while still allowing subsequent
dlls.load_after_fork to fail silently (for when the "forkable" hardlinks
are not created yet).
pinfo::remember not performing reattach anymore requires explicit
pinfo::reattach now where appropriate.
Prepares to improve "Cygwin: fork: Remember child not before success."
commit f03ea8e1c5, which leads to fork
problems if cygserver is running:
https://cygwin.com/ml/cygwin-patches/2019-q2/msg00155.html
Introducing an independent Cygwin PID introduced a regression:
The expectation is that the myself pinfo pointer always points to a
specific address right in front of the loaded Cygwin DLL.
However, the independent Cygwin PID changes broke this. To create
myself at the right address requires to call init with h0 set to
INVALID_HANDLE_VALUE or an existing address:
void
pinfo::init (pid_t n, DWORD flag, HANDLE h0)
{
[...]
if (!h0 || myself.h)
[...]
else
{
shloc = SH_MYSELF;
if (h0 == INVALID_HANDLE_VALUE) <-- !!!
h0 = NULL;
}
The aforementioned commits changed that so h0 was always NULL, this way
creating myself at an arbitrary address.
This patch makes sure to set the handle to INVALID_HANDLE_VALUE again
when creating a new process, so init knows that myself has to be created
in the right spot. While at it, fix a potential uninitialized handle
value in child_info_spawn::handle_spawn.
Fixes: b5e1003722 ("Cygwin: processes: use dedicated Cygwin PID rather than Windows PID")
Fixes: 88605243a1 ("Cygwin: fix child getting another pid after spawnve")
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
_pinfo::set_ctty sets myself's pgid to the ctty pgid if the process has
been started from a non-Cygwin process. This isn't the right thing to
do when started from GDB. GDB starts the application via standard
Windows means, not via Cygwin fork/exec, so it's treated as being
a non-Cygwin parent.
But we want the app running in it's own process group. So skip this
step when running under a debugger
Signed-off-by: Corinna Vinschen <corinna-cygwin@cygwin.com>
Return -1 with EINVAL if pgid < 0.
Previously tcsetpgrp() would blindly go ahead and set the pgid of the
controlling terminal to a negative value, causing later calls to
various functions to fail.
For example, gdb has code like the following:
tcsetpgrp (0, getpgid (inf->pid));
If getpgid (inf->pid) fails (returns -1), then this code would set the
pgid of fd 0 to -1, so that some later calls to getpgid() would also
return -1. This caused the problem reported here:
https://cygwin.com/ml/cygwin/2019-07/msg00166.html.
So far negative values were denoting files, positive values
denoting directories. We should prefer a less error prone
method. Redefine virtual_ftype_t to contain only positive
values and replace checks for negativ or positive values with
inline functions virt_ftype_isfile() and virt_ftype_isdir().
Drop outdcated comments referring to numerical virtual_ftype_t
values.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
commit 2607639992 "Improve error handling in /proc/[pid]/
virtual files." changed the return value of the /proc/PID
formatting functions to return -1 instead of 0 in the error
case to allow a filesize of 0.
The patch neglected to change this behaviour for /proc/PID/fd
content. This patch fixes that.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
Change path_conv::is_lnk_special() so that it returns false on socket
files.
is_lnk_special() is called by rename2() in order to deal with special
files (FIFOs and symlinks, for example) whose Win32 names usually have
a ".lnk" suffix. Socket files do not fall into this category, and
this change prevents ".lnk" from being appended erroneously when such
files are renamed.
Remove a now redundant !pc.issocket() from fhandler_disk_file::link().
It is used only once, and the name is supposed to suggest "device that
is not based on the filesystem". This intended meaning is clearer if
we just replace is_auto_device() by its definition at the place where
it's used.
The sigpending mechanism failed to check if the pending signal was a
process-wide signal, or a signal for the curent thread. Fix that by
adding a matching conditional to wait_sig's __SIGPENDING code.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
So far sig_send's return type is int. The problem with this is
that sig_send returns a sigset_t on __SIGPENDING, and sigset_t
is defined as long type. So the function only returns the lower
32 bit of sigset_t, which is fine on 32 bit, but casts away the
pending RT signals on 64 bit.
Fix this by changing the return type of sig_send to sigset_t, so
as not to narrow down the sigset when returning from handling
__SIGPENDING. Make sure to cast correctly in all invocations
of sig_send.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
Have sched_getaffinity() interface like glibc's, and provide an
undocumented internal interface __sched_getaffinity_sys() like the Linux
kernel's sched_getaffinity() for benefit of taskset(1).
Add a function timerfd_tracker::enter_critical_section_cancelable,
which is like enter_critical_section but honors a cancel event. Call
this when a timer expires while the timerfd thread is in its inner
loop. This avoids a deadlock if timerfd_tracker::dtor has entered its
critical section and is trying to cancel the thread. See
https://cygwin.com/ml/cygwin/2019-06/msg00096.html.
This patch set implements the Linux syscalls sched_getaffinity,
sched_setaffinity, pthread_getaffinity_np, and pthread_setaffinity_np.
Linux has a straightforward view of the cpu sets used in affinity masks.
They are simply long (1024-bit) bit masks. This code emulates that view
while internally dealing with Windows' distribution of available CPUs among
processor groups.
Make it a manual reset event. It's only used once to allow a reader
to open, and there's no reason to ever reset it. Defensively set it
when a client connection is recorded, even though it should be set by
the writer that connected.
Call NtReadFile directly instead of calling fhandler_base::raw_read.
In addition to being simpler, this gives us access to the return value
from NtReadFile.
Add a method fifo_client_handler::pipe_state that queries Windows for
the state of a pipe instance. Use this to help terminate the
listen_client thread cleanly.
If the last client handler is useless, delete it instead of declaring
it invalid.
fhandler_fifo::close could be called from a signal handler or another
thread at a time when another function is holding the fifo_client
lock. This could prevent the listen_client thread from acting on the
thread termination event. Avoid a deadlock by calling
fifo_client_unlock at the beginning of fhandler_fifo::close.
libX11 provides <X11/Xlocale.h>. The build of libX11 itself adds
include/X11 to the compiler's include path. This results in a name
collision with /usr/include/xlocale.h on case-insensitive filesystems.
Commit 90e35b1eb3 renamed sys/_locale.h to xlocale.h in March 2017 under
the assumption that we should provide the locale_t type in the same file
as on Linux, FreeBSD, and Darwin.
A few weeks later (June 2017), glibc removed the xlocale.h file in favor
of bits/types/locale_t.h, which shouldn't be included directly anyway.
For reference and the reasoning, see
https://sourceware.org/git/?p=glibc.git;a=commit;h=f0be25b6336d
Given the above, revert 90e35b1eb3 and
fix additional usage of xlocale.h.
32 bit Cygwin performs a POSIX-compatible mapping after EOF which
is not supported in this form on Windows. The 64 bit Windows
kernel never supported the AT_ROUND_TO_PAGE mapping flag, so we
couldn't page-aligned map the space right after the file's EOF.
So mapping beyond EOF was disabled in 64 bit Windows and WOW64.
However, if mmap works, a matching munmap should work as well,
*and* it should not accidentally unmap unrelated memory.
Therefore we enable mapping beyond EOF on 64 bit as well. Since
that mapping is always 64K aligned, the are between the last file
page and the next 64K allocation boundary will be unallocated.
There's no way around that.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
When using NtCreateFile when creating a directory that already exists,
it will correctly return 'STATUS_OBJECT_NAME_COLLISION'.
However using this function to create a directory (and all its parents)
a normal use would be to start with mkdir(‘/cygdrive/c’) which translates
to ‘C:\’ for which it'll instead return ‘STATUS_ACCESS_DENIED’.
An increasing number of tools are being included in Windows which have the
same names as those included in Cygwin packages. Indicating which one is
first in PATH can be helpful in diagnosing behavioural discrepencies
between them.
Also, fix the alphabetization of ssh.
64 bit Windows started out with a 44 bit address space due to a
restriction of the AMD64 CPUs at the time. Starting with Windows
8.1, these CPUs are not supported anymore and Windows switched to
the full 48 bit address space supported by AMD64.
Cygwin didn't follow suit yet so mmaps are still restricted to
the lower 44 bit address space. Fix that by using a system-specific
upper address for mmap allocations, 44 bit up to Windows 8, 48 bit
starting with Windows 8.1.
While at it, move the heap by another 8 Gigs to leave some space
for a potential extension of DLL address space, and restrict the
mmap lower address so the heap can grow to 32 Gigs before colliding
with mmaps.
Do not remember the child before it was successfully initialized, or we
would need more sophisticated cleanup on child initialization failure,
like cleaning up the process table and suppressing SIGCHILD delivery
with multiple threads ("waitproc") involved. Compared to that, the
potential slowdown due to an extra yield () call should be negligible.
Pause the child process after performing fork fixups even if there were
no dynamically loaded dlls with extra data/bss transfers to wait for.
This allows the parent process to cancel the current fork call even if
the child process was successfully initialized already.
This is a preparation for when the parent does remember the child no
earlier than after successful child initialization.
Querying the ntlength and existence of the /var/run/cygfork directory in
the very first Cygwin process should not use nt_max_path_buf, as that
one is used by dll_list::alloc already.
NtQueryVirtualMemory for MemorySectionName may return some old path even
if the process was just started, for when some directory in between was
renamed - maybe because the NT file cache is hot for the old path still.
This was seen during gcc bootstrap, returning a MemorySectionName of
".../gcc/xgcc.exe" even if started as ".../prev-gcc/xgcc.exe", where the
directory rename from "gcc" to "prev-gcc" was done the moment before.
As we stat the module's real file right after loading now, there is no
point in using NtQueryVirtualMemory with MemorySectionName any more, and
we can use what GetModuleFileName returned instead.
-Add vendor identification
-Support in get_cpu_cache
Background:
Chengdu Haiguang IC Design Co., Ltd (Hygon) is a Joint Venture
between AMD and Haiguang Information Technology Co.,Ltd., aims at
providing high performance x86 processor for China server market.
Its first generation processor codename is Dhyana, which
originates from AMD technology and shares most of the
architecture with AMD's family 17h, but with different CPU Vendor
ID("HygonGenuine")/Family series number(Family 18h).
Related Hygon kernel patch can be found on:
http://lkml.kernel.org/r/5ce86123a7b9dad925ac583d88d2f921040e859b.1538583282.git.puwen@hygon.cn
Signed-off-by: Jinke Fan <fanjinke@hygon.cn>
There's no longer a need to consider the connect_evt after fork/exec.
After stopping the listen_client thread, all client handlers should be
in the fc_connected or fc_invalid states, so their connect_evt members
won't be used again.
Also remove code in fhandler_fifo::dup that just repeats things
already done in stop_listen_client.
Add a method fhandler_fifo::check_listen_client_thread that checks
whether the thread is running. Use it in raw_read instead of just
testing the handle listen_client_thr.
On exit from the listen_client thread, make sure there's no pending
FSCTL_PIPE_LISTEN request. Otherwise we might get a client connection
after restarting the thread, and we won't have a handle for
communicating with that client.
Remove the retry loop in the case of STATUS_PIPE_LISTENING; that case
shouldn't occur.
Remove the now-unused fc_connecting value from
fifo_client_connect_state.
It's now up to the caller to pass a handle to open_pipe and, if
desired, to call set_handle on return.
This will be useful for a future commit, in which we will open a
client connection without setting an io_handle.
When opening a duplexer, open a client connection to the first client
handler. Previously we gave the duplexer a bogus write handle, which
was just a duplicate of the first client handler's handle. This meant
that we had a pipe server with no clients connected, and all I/O
attempts failed with STATUS_PIPE_LISTENING.
Extend the last fcntl change to duplexers.
Remove a now unused fifo_client_handler constructor, as well as the
long unusued method fifo_client_handler::connect.
Don't create the pipe in duplex mode; the server handle will only be
used for reading.