- In pipe_data_available() in select.cc, PeekNamedPipe() call is
not needed if WriteQuotaAvailable is non-zero because we already
know the write pipe has a space. Therefore, with this patch,
PeekNamedPipe() is called only when WriteQuotaAvailable is zero.
This makes select() on pipe faster a bit.
- Currently, raw_read(), raw_write() and close() release select_sem
unconditionally even if no waiter for select_sem exists. With this
patch, only the minimum number of semaphores required is released.
- Usually WriteQuotaAvailable retrieved by NtQueryInformationFile()
on the write side reflects the space available in the inbound buffer
on the read side. However, if a pipe read is currently pending,
WriteQuotaAvailable on the write side is decremented by the number
of bytes the read side is requesting. So it's possible (even likely)
that WriteQuotaAvailable is 0, even if the inbound buffer on the
read side is not full. This can lead to a deadlock situation:
The reader is waiting for data, but select on the writer side
assumes that no space is available in the read side inbound buffer.
Currently, to avoid this stuation, read() does not request larger
block than pipe size - 1. However, this mechanism does not take
effect if the reader side is non-cygwin app.
The only reliable information is available on the read side, so
fetch info from the read side via the pipe-specific query handle
(query_hdl) introduced.
If the query_hdl (read handle) is kept in write side, writer can
not detect closure of read pipe. Therefore, raw_write() counts
write handle and query_hdl. If they are equal, only the pairs of
write handle and query_hdl are alive. In this case, raw_write()
returns EPIPE and raises SIGPIPE.
- Nonblocking pipes (PIPE_NOWAIT) are not well handled by non-Cygwin
tools, so convert pipe handles to PIPE_WAIT handles when spawning
a non-Cygwin process.
We already fetched the correct SECURITY_ATTRIBUTES at the start of
fhandler_pipe::create, so using another SECURITY_ATTRIBUTES object for
the mutex and semaphore objects doesn't make much sense.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
select_sem gets created on the read side with inheritence settings
depending on the O_CLOEXEC flag. Then it gets duplicated to the write
side with unconditional inheritence. Fix that.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
Fold all code branches potentially having read or written data into
a single if branch, so signalling select_sem catches all cases.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
Rename fhandler_pipe_and_fifo::max_atomic_write to pipe_buf_size.
This reflect its actual meaning better. The fhandler_pipe_and_fifo
constructor initializes it to DEFAULT_PIPEBUFSIZE (== 64K), which is
the buffer size for the windows pipes created by fhandler_pipe and
fhandler_fifo. But if we inherit a stdio pipe handle from a
non-Cygwin process, the buffer size could be different.
To remedy this, add a method fhandler_pipe::set_pipe_buf_size that
queries the OS for the pipe buffer size, and use it in
dtable::init_std_file_from_handle.
Given we return 1 already if WriteQuotaAvailable is > 0, the condition
for tiny pipes is never true. Fix the comments.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
In blocking mode, the underlying IO must always be terminated,
one way or the other, to make sure the application knows the exact
state after returning from the IO function. Therefore, always call
CancelIo in blocking mode.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
Just cancelling a thread doesn't cancel async IO started by this thread.
Fix this by returning from cygwait and calling CancelIo before canceling
self.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
- By guarding read with read_mtx, no more than one ReadFile can
be called simultaneously. So couting read handles is no longer
necessary.
- Make raw_read code as similar as possible to raw_write code.
This is a parent of fhandler_pipe and fhandler_fifo for code that is
common between the two classes. Currently it just contains
max_atomic_write and raw_write(). The latter is identical to what
used to be fhandler_pipe::raw_write().
FILE_PIPE_LOCAL_INFORMATION::WriteQuotaAvailable is unreliable.
Usually WriteQuotaAvailable on the write side reflects the space
available in the inbound buffer on the read side. However, if a
pipe read is currently pending, WriteQuotaAvailable on the write side
is decremented by the number of bytes the read side is requesting.
So it's possible (even likely) that WriteQuotaAvailable is 0, even
if the inbound buffer on the read side is not full. This can lead to
a deadlock situation: The reader is waiting for data, but select
on the writer side assumes that no space is available in the read
side inbound buffer.
This patch implements a workaround by never trying to read more than
half the buffer size blocking if the read buffer is empty. This first
cut tries to take the number of open readers into account by reducing
the amount of requested bytes accordingly.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
POSIX requires atomicity for non-blocking writes <= PIPE_BUF bytes
and writing of at least 1 byte if any buffer space is left.
Windows NtWriteFile returns STATUS_SUCCESS and "0 bytes written"
if the write doesn't match buffer space. Fix this discrepancy.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
The buffer pointer is incremented by "chunk", which is what we
typically try to write, but this isn't what actually got written.
Increment the buffer pointer by what we actually wrote, as returned
by NtWriteFile.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
get_obj_handle_count() is used in flock only so far, but pipe
handling might have a usage, too, soon. Given that this function
might be generally useful and isn't restricted to flock usage,
move it to miscfuncs.cc and make it non-static. Add a prototype
in miscfuncs.h.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
I wasted valuable minutes of my life just to find out why we export
this weird version of pipe. In the pre-2000 era the idea was Cygwin
could be used as drop-in replacement for msvcrt.dll, apparently.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
The read handles of pipes created by CreateNamedPipe don't have
FILE_WRITE_ATTRIBUTES access unless the pipe is created with
PIPE_ACCESS_DUPLEX. This causes set_pipe_non_blocking to fail on such
handles. To fix this, add a helper function nt_create, which uses
NtCreateNamedPipeFile instead of CreateNamedPipe and gives us more
flexibility in setting access rights.
Use this helper function in fhandler_pipe::create (fhandler_pipe *[2],
unsigned, int), which is the version of fhandler_pipe::create used by
the pipe and pipe2 system calls.
For convenience, also add a static member function
fhandler_pipe::npfs_handle similar to those used by fhandler_fifo and
fhandler_socket_unix.
Add methods 'set_pipe_non_blocking' and 'fcntl' to keep the blocking
mode of the Windows pipe in sync with that of the fhandler_pipe
object. This applies to pipes created with the 'pipe' and 'pipe2'
system calls.
Previously fhandler_pipe was derived from fhandler_base_overlapped,
which we are going to remove in a future commit. Make minimal changes
so that the build still succeeds.
In https://cygwin.com/pipermail/cygwin/2021-September/249361.html
Brian pointed out that initializing the structure would be more
future proof, should the developers at Microsoft ever decide to
split the Reserved field and use some bits of the struct for
other purposes.
Fixes: 3d322ac930 ("Cygwin: fix initializing MEM_EXTENDED_PARAMETER")
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
MEM_EXTENDED_PARAMETER consists of a 64 bit bitfield which contains
the Type and the Reserved members. The former usage of designated
initializer lists initialized Type, but not Reserved. Since that's
not possible anymore due to a g++ 11.2 bug, Cygwin initializes the
MEM_EXTENDED_PARAMETER structs explicitely. This results in a
random value in Reserved, which at least VirtualAlloc2 chokes on
(ERROR_INVALID_PARAMETER).
Set Reserved explicitely to 0 for a fix.
Fixes: bdb7991db3 ("Cygwin: workaround a g++ 11.2 initialization bug")
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
The handle is created non-inheritable but gets inheritable when
dup'ing the file descriptor. Fix that.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
Modern gcc's generate additional DWARF 5 debug sections, which were
still missing in our Cygwin loader script. With ld from binutils 2.37,
this results in diagnostic output when linking the Cygwin DLL...
ld: cygwin0.dll:/4: section below image base
ld: cygwin0.dll:/20: section below image base
ld: cygwin0.dll:/36: section below image base
...and the section addresses given to these sections (.debug_loclists,
.debug_rnglists, debug_line_str) will be wrong.
Fix this by adding the missing DWARF 5 sections to our linker script
template cygwin.sc.in. Add a comment in terms of the deprecated
DWARF 4 section .debug_types.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
Signed-off-by: Jon Turney <jon.turney@dronecode.org.uk>
This was used before switching to automake to allow easy tweaking
of optimization and debugging settings from the command line during
testing. Reenable.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
trying to use aggregate initialization syntax on a member of a
nameless union member failes in g++ 11.2.
Workaround this by using explicit initialization.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
The GCC diagnostic ignored "-Wstringop-overflow" pragma doesn't work
as expected anymore. Use the still working expression.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
The register keyword was already deprecated with C++11, but
with C++17 it has been entirely removed.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
Revert mx parameter and mutex lock while operating the list.
Mutex was removed with 94d24160 informing that:
'Use InterlockedCompareExchangePointer to ensure race safeness
without using a mutex.'
But it does not.
Calling pthread_mutex_init and pthread_mutex_destroy from two or
more threads occasionally leads to hang in pthread_mutex_destroy.
To not change the behaviour of other cases where List_insert was called,
List_insert_nolock is added.
As outlined in the previous patch, the non-atomicity of iterating
over a directory in the NT namespace via NtQueryDirectoryObject
one entry each, results in potential duplication of directory entries.
Fix this for fhandler_procsys::readdir as well by fetching the entire
dir inside fhandler_procsys::opendir, storing it in a buffer, and just
return buffer content from fhandler_procsys::readdir.
Fixes: 43f65cdd7d ("fhandler_procsys.cc: New file.")
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
Due to reports on the Cygwin mailing list[1][2], it was uncovered
that a NtOpenDirectoryObject/NtQueryDirectoryObject/NtClose sequence
with NtQueryDirectoryObject iterating over the directory entries,
one entry per invocation, is not running atomically. If new entries
are inserted into the queried directory, other entries may be moved
around and then accidentally show up twice while iterating.
Change (almost) all NtQueryDirectoryObject invocations so that it gets
a really big buffer (64K) and ideally fetches all entries at once.
This appears to work atomically.
"Almost" all, because fhandler_procsys::readdir can't be easily changed.
[1] https://cygwin.com/pipermail/cygwin/2021-July/248998.html
[2] https://cygwin.com/pipermail/cygwin/2021-August/249124.html
Fixes: e9c8cb3193 ("(format_proc_partitions): Revamp loop over existing harddisks by scanning the NT native \Device object directory and looking for Harddisk entries.")
Fixes: a998dd7055 ("Implement advisory file locking.")
Fixes: 3b7cd74bfd ("(winpids::enum_processes): Fetch Cygwin processes from listing of shared cygwin object dir in the native NT namespace.")
Fixes: 0d6f2b0117 ("syscalls.cc (sync_worker): Rewrite using native NT functions.")
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
Commit 3434d35a64 fixed a problem when
accessing block devices via their /proc/sys/Device entries. This
changed the way stat info is generated for these devices, resulting
in identical inode numbers for all block devices under /proc/sys/Device.
This patch fixes that by faking a device number for these devices, just as
before.
Fixes: 3434d35a64 ("Cygwin: Fix access to block devices below /proc/sys.")
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
Make sure to cast to ulong all DWORD values displayed with format "%lu".
More instances are fixed here than in either my earlier unused patch or
Corinna's patch. I decided to use typedef..ulong for more compact code.
Address jturney's reported small issues:
- Remove explicit external ref for cygwin_internal() as it is already
provided by <sys/cygwin.h>.
- Leave intact ref for cygwin_dll_path[] as it is required by function(s)
in path.cc that profiler uses. Added comment to that effect.
- Delete existing main() wrapper. Rename main2() to main(). This because
profiler is now a Cygwin program and doesn't need to dynamically load
cygwin1.dll.
- Documentation issues will be addressed in a separate xml patch.
(I would have linked message-ids of Corinna's and Jon's messages for
proper theading but I no longer have their original emails and the mail
archives don't show msgids any more.)
The doc for gmondump says 1 or more FILENAME are expected, but 0 is
handled. That's an oversight. Make invocation with 0 FILENAMEs print a
one-line help message.
Reword the beginning of profiler's description doc to clarify target's
child processes are run but only optionally profiled.
If a service is supported as TCP and UDP service, GetAddrInfo does not
return two entries, one for TCP, one for UDP, as on Linux. Rather, it
just returns a single entry with ai_socktype and ai_protocol set to 0.
If the service only exists as TCP or UDP service, then ai->ai_socktype
is set, but ai_protocol isn't.
Fortunately we copy over the result from Windows into local storage
anyway, so this patch adds code to fix up the fields neglected by
Windows. In case ai_socktype as well as ai_protocol are 0, duplicate
the entry with valid values for ai_socktype and ai_protocol.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
If an interface is disconnected, net.cc:get_ifs tries to fetch IPv4
addresses from the registry. If it fails, it currently returns
pointers to sockaddr structs with zero address. Return a NULL pointer
instead, to signal the caller of getifaddrs that we do not have a
valid struct sockaddr.
Partially addresses: https://cygwin.com/pipermail/cygwin/2021-July/248970.html
It appears to be the case that NtQueryTimer can return a negative time
remaining for an unsignalled timer. The value appears to be less than
the timer resolution.
Signed-off-by: David Allsopp <david.allsopp@metastack.com>
DWORD has different types on 32 and 64 bit. Use a common cast to
unsigned long to use %lu format for DWORD values throughout.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
These are updates to wire into the build tree the new tools profiler and
gmondump, and to supply documentation for the tools.
The documentation for profiler and ssp now mention each other but do not
discuss their similarities or differences. That will be handled in a
future update to the "Profiling Cygwin Programs" section of the Cygwin
User's Guide, to be supplied.
This new tool was formerly part of 'profiler' but was spun out thanks to
Jon T's reasonable review comment. Gmondump is more of a debugging tool
than something users might have need for. Users would more likely use
gprof to make use of symbolic info like function names and source line
numbers.
The new tool formerly known as cygmon is renamed to 'profiler'. For the
name I considered 'ipsampler' and could not think of any others. I'm open
to a different name if any is suggested.
I decided that a discussion of the pros and cons of this profiler vs the
existing ssp should probably be in the "Profiling Cygwin Programs" section
of the Cygwin User's Guide rather than in the help for either. That
material will be supplied at some point.
CONTEXT buffers are made child-specific and thus thread-specific since
there is one profiler thread for each child program being profiled.
The SetThreadPriority() warning comment has been expanded.
chmod() works on Cygwin so the "//XXX ineffective" comment is gone.
I decided to make the "sample all executable sections" and "sample
dynamically generated code" suggestions simply expanded comments for now.
The profiler program is now a Cygwin exe rather than a native exe.
The Linux man page for cfsetspeed(3) specifies that the speed argument
must be one of the constants Bnnn (e.g., B9600) defined in termios.h.
But Linux in fact allows the speed to be the numerical baud rate
(e.g., 9600). For consistency with Linux, we now do the same.
Addresses: https://cygwin.com/pipermail/cygwin/2021-July/248887.html
The default PSAPI_VERSION is controlled by WIN32_WINNT, which we set to
0x0a00 when building utils since 48a76190 (and is the default in w32api
>= 9.0.0)
In order for the built executables to run on Windows Vista, we must also
define PSAPI_VERSION as 1 (otherwise '#define GetModuleFileNameExA
K32GetModuleFileNameExA' causes a 'The procedure entry point
K32GetModuleFilenameExA could not be located in the dynamic link library
kernel32.dll' error at run time).
Also drop uneeded psapi.h from dlfcn.cc (31ddf45d), resource.cc
(34a6eeab) and ps.cc (1def2148).
Use <cmdsynopsis> element markup in utils docbook documentation, rather
than some preformatted text inside <screen>.
(This didn't happen as part of 646745cb, when we first started using
refentry elements to make it possible to generate manpages)
This helps produce better looking manpages:
* uses bold (for command names) and italic (for replaceable items)
* different output formats inconsistently treat tabs inside <screen>
(so we have to be careful to not use them in that preformatted text)
Also clean up various issues:
* Replace '[OPTIONS]' with a real synopsis of the options
* Consistently use 'ITEM...' rather than 'ITEM1 [ITEM2...]' for an item
which should appear 1 or more times (cygcheck -f, getfacl, kill)
* Consistently document the '-h | -V' invocation form
* Since replaceable items are now marked up so they have some formatting
indicating they are replaceable, we can drop wrapping them in angle
brackets, as is done in some places
* Add missing '-W' and '-p PID' options to ps synopsis
* Adjust cygpath synopsis to show that only one 'System information'
option is allowed, possibly modified by -A
Future work:
* Sync up the actual help emitted by the util, where it's been improved
* Also don't use <screen> for formatting 'OPTIONS' section of manpage
* pldd inconsistently uses '-?' rather than '-h'!
* Drop duplicate 'Options:' headers (mkgroup, mkpassword)
* Add missing indication that MACHINE is optional with -L (mkgroup, mkpassword)
* Tweak some <refpurpose> which try to be a synopsis, rather than a decription (passwd, ssp)
* Drop some stray '\n' in setfacl options
* Move 'Original Author' note in ssp to an AUTHORS section
* Use <para> to improve formatting of tzset manpage
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
The new GetFinalPathNameW handling for native symlinks in inner path
components is disabled if caller doesn't want to follow symlinks, or
doesn't want to follow reparse points.
Corinna Vinschen
Takashi Yano
Ken Brown
Aleksand Malikov
Mark Geisert
Jon Turney
David Allsopp
Thomas Wolff
Jeremy Drake
Brian Inglis