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.
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>
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.
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>
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.
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.
commit d1be0a59d4,
"Cygwin: winpids: Fix getting process multiple times"
fixed duplicate processes in ps -W output, but it fixed
the symptom, not the cause. It also didn't fix the problem
that the `ps' process itself may show up twice in its own
output.
This patch fixes it. The spawn worker only deleted the
"winpid.PID" symlink of the current process if the child is
a non-Cygwin process, under the assumption that the exec'ing
process exits anyway. However, the Window in which both
winpid.PID symlinks point to the same cygpid.PID area is just
too long. The spawn worker now also deletes its own winpid.PID
symlink if the exec'ed process is a Cygwin process.
Additionally the fix from d1be0a59d4
is now performed on the calling process, too.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
commit c0d7d3e1a2 removed the usage of the
LCMAP_BYTEREV flag in the call to LCMapStringW to workaround a strange
bug in LCMapStringW. This patch didn't take a userspace call of
wcsxfrm{_l} with NULL buffer and 0 size to evaluate the required buffer
size into account. This introduced a crash trying to byte swap the
NULL buffer. This patch fixes that problem.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
3.0.0 changed uname but missed to align /proc/version
which then used the old uname function on the new uname
struct.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
The winpid symlinks got created with no query permissions, so
only admins could see all Cygwin processes. Create symlinks
so everyone has query permissions instead.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
Canceling the timer thread runs under lock. The thread uses the same
lock to guard its timer_tracker struct access. If the timing is bad,
timer_settime or timer_delete grab the lock at the same time, the timer
expires. In the end, cancel waits for the thread sync while the thread
waits for ther lock to be released.
Fix this by not waiting for the thread sync under lock.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
On setting the timer, the thread is accidentally only canceled when
disarming the timer. This leaks one thread per timer_settimer call.
Move the thread cancellation where it belongs.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
Inspecting the content of case-sensitive directories
on remote machines results in lots of errors like
disappearing diretories and files, file not found, etc.
This is not feasible as default behaviour
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
timerfd_tracker::fixup_after_fork_exec always tries to restore
the shared timer region at the same address as in the parent.
This is entirely unnecessary and wasn't intended, rather some
kind of copy/paste thinko. Fix that. Print NtMapViewOfSection
status code in api_fatal on failure for debugging.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
The "optimized" condition to recognize an unarmed timer was plain
wrong. Replace it by checking the stored it_value against 0.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
Under WOW64 on 64 bit Windows 7, MsV1_0S4ULogon appears to be
unimplemented, probably under Vista as well. Re-enable
create_token method, to allow basic seteuid on W7 WOW64 and
Vista as well.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
Commit c1023ee353 changed the way
path_conv::binmode() works. Rather than returning three states,
O_BINARY, O_TEXT, 0, it only returned 2 states, O_BINARY, O_TEXT. Since
mounts are only binary if they are explicitely mounted binary by setting
the MOUNT_BINARY flag, textmode is default.
This introduced a new bug. When inheriting stdio HANDLEs from native
Windows processes, the fhandler and its path_conv are created from a
device struct only. None of the path or mount flags get set this way.
So the mount flags are 0 and path_conv::binmode() returned 0.
After the path_conv::binmode() change it returned O_TEXT since, as
explained above, the default mount mode is textmode.
Rather than just enforcing binary mode for path_conv's created from
device structs, this patch changes the default mount mode to binary:
Replace MOUNT_BINARY flag with MOUNT_TEXT flag with opposite meaning.
Drop all explicit setting of MOUNT_BINARY. Drop local set_flags
function, it doesn't add any value.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
When recognizing a negative pid, optind is off by one. The
code correcting this has been erroneously removed by commit
8de660271f. Revert that.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
When looking up valid accounts by name, LookupAccountName returns
a SID and a case-correct domain name. However, the name was input
and LookupAccountName is case-insensitive, so the name is not
necessarily written the same way as in SAM or AD.
Fix that by doing a reverse lookup on the just fetched SID. This
fetches the account name in the correct case. Override the
incoming name with the case correct name from LookupAccountSid.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
dtable::set_file_pointers_for_exec is called from
child_info_spawn::worker to move the file position of O_APPEND
files to EOF if the child is a native child.
However, this only works correctly for the first O_APPEND
file descriptor:
- set_file_pointers_for_exec calls SetFilePointer. The higher
4 bytes of the desired file offset are given to SetFilePointer
as pointer to a DWORD value. On return, SetFilePointer returns
the higher 4 bytes of the new file position in this DWORD.
- So for the second and subsequent descriptors the higher 4 byte
of the file position depend on what the actual file position
of the previous file has been set to:
- If the file is > 2 Gigs, the high offset will not be 0 anymore.
- If the desciptor points to a non-seekable file (i.e., a pipe
or socket), SetFilePosition returns an error and sets the high
position to -1.
Fix this by calling SetFilePointerEx instead, which does not
modify the incoming position value.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
Using the Windows PID as Cygwin PID has a few drawbacks:
- the PIDs on Windows get reused quickly. Some POSIX applications choke
on that, so we need extra code to avoid too quick PID reuse.
- The code to avoid PID reuse keeps parent process handles and
(depending on a build option) child processes open unnecessarily.
- After an execve, the process has a split personality: Its Windows PID
is a new PID, while its Cygwin PID is the PID of the execve caller
process. This requires to keep two procinfo shared sections open, the
second just to redirect process info requests to the first, correct
one.
This patch changes the way Cygwin PIDs are generated:
- Cygwin PIDs are generated independently of the Windows PID, in a way
expected by POSIX processes. The PIDs are created incrementally in
the range between 2 and 65535, round-robin.
- On startup of the first Cygwin process, choose a semi-random start PID
for the first process in the lower PID range to make the PIDs slightly
unpredictable. This may not be necessary but it seems kind of inviting
to know that the first Cygwin process always starts with PID 2.
- Every process not only creates the shared procinfo section, but also a
symlink in the NT namespace, symlinking the Windows PID to the Cygwin
PID. This drops the need for the extra procinfo section after execve.
- Don't keep other process handles around unnecessarily.
- Simplify the code creating/opening the shared procinfo section and
make a clear distinction between interfaces getting a Cygwin PID and
interfaces getting a Windows PID.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
POSIX requires that raise(3) is equivalent to
pthread_kill(pthread_self(), sig);
in multi-threaded applications. Our raise just called kill(sig).
Fix that.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
- This simple and official method replaces cyglsa and "create token"
methods. No network share access, same as before.
- lsaauth and create_token are disabled now. If problems crop up,
they can be easily reactivated. If no problems crop up, they
can be removed in a while, together with the lsaauth subdir.
- Bump Cygwin version to 3.0.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
So far seteuid could change uid to any existing account, given
sufficient permissions of the caller. This is kind of bad since
it disallows admins to refuse login to disabled or locked out
accounts.
Add check for the account's UF_ACCOUNTDISABLE or UF_LOCKOUT flags
and don't let the user in, if one of the flags is set.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
If gethostname() fails we call GetComputerNameEx with
ComputerNameDnsFullyQualified. This is wrong, gethostname should return
the hostname only, not the FQDN. Fix this by calling GetComputerNameEx
with ComputerNameDnsHostname.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
When reusing a cygthread, the stub method fails to set the thread name
to the new name. The name is only set when actually creating the
thread. Fix that by moving the SetThreadName call right in front of the
thread function call.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
First cut of a timerfd implementation.
Still TODO:
- fork/exec semantics
- timerfd_settime TFD_TIMER_CANCEL_ON_SET flag
- ioctl(TFD_IOC_SET_TICKS)
- bug fixes
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
First cut of a signalfd implementation.
Still TODO: Non-polling select.
This should mostly work as on Linux except for missing support
for some members of struct signalfd_siginfo, namely ssi_fd,
ssi_band (both SIGIO/SIGPOLL, not fully implemented) and ssi_trapno
(HW exception, required HW support).
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
There's a long-standing bug in select. If we have poll-only
descriptors in the fd set, select overwrites the incoming
fd sets with the polling result. If none of the fds is ready,
select has to loop again. But now the fd sets are set to all
zero and select hangs.
Fix this by utilizing the local fd sets r, w, e as storage for
the incoming fd sets and use them to initialize select_stuff.
If we have to loop, overwritung the incoming fd sets doesn't matter.
While at it, rename r, w, e to readfds_in, writefds_in, exceptfds_in.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
fhandler_socket_wsock::set_socket_handle calls set_flags after
setting the O_NONBLOCK/O_CLOEXEC flags, thus overwriting them.
It also turns out that fhandler_socket_wsock::init_events is called
too late. The inheritence flags are changed before creating the
socket event handling objects. Thus, inheritence flags for
those objects are wrong with SOCK_CLOEXEC.
Fix this by reordering the calls and setting the file flags through
fhandler_base::set_flags.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
Regression introduced with 2.11.0:
The failure paths in socket, socketpair and accept4 functions and
methods accidentally release *unused* cygheap_fdmanip objects. The
subsequently called dtable::release method was designed to be called for
*used* cygheap_fdmanip objects only. Using them on unused objects leads
to NULL pointer member dereferencing.
Worse, the inet/local accept4 methods only release the cygheap_fdmanip
object but neglect to delete the just created fhandler_socket_* object.
Fix this by removing the erroneous release calls in the aforementioned
failure paths and delete the fhandler_socket_* object in accept4 instead.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
The fhandler_base_overlapped::copyto clears atomic_write_buf on the
clone, but none of the derived classes were doing this. This allowed
the destructor to double-free the buffer and corrupt cygheap.
Clear atomic_write_buf in copyto of all derived classes.
Commit 35998fc2fa fixed the buffer underun
in win32 path normalization, but introduced a new bug: A wrong
assumption led to the inability to backtrack the path outside of the
current working directory in case of relative paths.
This patch fixes this problem, together with a minor problem if the CWD
is on a network share: The result erroneously started with tripple
backslash if the src path starts with a single backslash.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
Starting with Windows 10, LookupAccountSid/Name return valid
info for the login session with new SID_NAME_USE value
SidTypeLogonSession. To return the same info as on pre-Windows 10,
we have to handle this type.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
This patch follows glibc. Original commit message:
Author: Florian Weimer <fweimer@redhat.com>
Date: Thu, 14 Apr 2016 06:54:57 +0000
Remove union wait [BZ #19613]
The overloading approach in the W* macros was incompatible with
integer expressions of a type different from int. Applications
using union wait and these macros will have to migrate to the
POSIX-specified int status type.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
* create new function __get_cpus_per_group to evaluate # of CPU groups
* Call from format_proc_cpuinfo and sched_getcpu
* Bump API minor version
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
Updates to misc files to integrate AIO into the Cygwin source tree.
Much of it has to be done when adding any new syscalls. There are
some updates to limits.h for AIO-specific limits. And some doc mods.
Certain tape drives (known example: QUANTUM_ULTRIUM-HH6) return
the non-standard ERROR_NOT_READY rather than ERROR_NO_MEDIA_IN_DRIVE
if no media is present. ERROR_NOT_READY is not documented as valid
return code from GetTapeStatus. Without handling this error code
Cygwin's tape code can't report an offline state to user space.
Fix this by converting ERROR_NOT_READY to ERROR_NO_MEDIA_IN_DRIVE
where appropriate.
Add a debug_printf to mtinfo_drive::get_status to allow requesting
user info without having to rebuild the DLL.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
- Move pthread_join to thread.cc to have all `join' calls in
the same file (pthread_timedjoin_np needs pthread_convert_abstime
which is static inline in thread.cc)
- Bump API version
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
When reading/writing block devices, Cygwin emulates Linux, providing
a byte-exact file position, albeit the underlying device drivers don't.
Unfortunately this only worked correctly for reading. The raw_write
method failed to revalidate the buffer after the read-modify-write
cycle in case len is not a multiple of the sector length. This in
turn resulted in lseek reporting a wrong file pointer.
Also, fix a condition for invalidating the buffer after writing from
a remaining read buffer.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
The original dll_init code was living under the wrong assumption that
dll_dllcrt0_1 and in turn dll_list::alloc will be called for each
LoadLibrary call. The same wrong assumption was made for
cygwin_detach_dll/dll_list::detach called via FreeLibrary.
In reality, dll_dllcrt0_1 gets only called once at first LoadLibrary
and cygwin_detach_dll once at last FreeLibrary.
In effect, reference counting for DLLs was completely broken after fork:
parent:
l1 = dlopen ("lib1"); // LoadLibrary, LoadCount = 1
l2 = dlopen ("lib1"); // LoadLibrary, LoadCount = 2
fork (); // LoadLibrary in the child, LoadCount = 1!
child:
dlclose (l1); // FreeLibrary actually frees the lib
x = dlsym (l2); // SEGV
* Move reference counting to dlopen/dlclose since only those functions
have to keep track of loading/unloading DLLs in the application context.
* Remove broken accounting code from dll_list::alloc and dll_list::detach.
* Fix error handling in dlclose.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
Note that this always returns with dli_sname and dli_saddr set to NULL,
indicating no symbol matching addr could be found.
Signed-off-by: Jon Turney <jon.turney@dronecode.org.uk>
This patch alters the behaviour of dll_list::topsort to preserve the
order of dlopen'd units.
The load order of unrelated DLLs is reversed every time fork is called,
since dll_list::topsort finds the tail of the list and then unwinds to
reinsert items. My change takes advantage of what should be undefined
behaviour in dll_list::populate_deps (ndeps non-zero and ndeps and deps
not initialised) to allow the deps field to be initialised prior to the
call and appended to, rather than overwritten.
All DLLs which have been dlopen'd have their deps list initialised with
the list of all previously dlopen'd units. These extra dependencies mean
that the unwind preserves the order of dlopen'd units.
The motivation for this is the FlexDLL linker used in OCaml. The FlexDLL
linker allows a dlopen'd unit to refer to symbols in previously dlopen'd
units and it resolves these symbols in DllMain before anything else has
initialised (including the Cygwin DLL). This means that dependencies may
exist between dlopen'd units (which the OCaml runtime system
understands) but which Windows is unaware of. During fork, the
process-level table which FlexDLL uses to get the symbol table of each
DLL is copied over but because the load order of dlopen'd DLLs is
reversed, it is possible for FlexDLL to attempt to access memory in the
DLL before it has been loaded and hence it fails with an access
violation. Because the list is reversed on each call to fork, it means
that a subsequent call to fork puts the DLLs back into the correct
order, hence "even" invocations of fork work!
An interesting side-effect is that this only occurs if the DLLs load at
their preferred base address - if they have to be rebased, then FlexDLL
works because at the time that the dependent unit is loaded out of
order, there is still in memory the "dummy" DONT_RESOLVE_DLL_REFERENCES
version of the dependency which, as it happens, will contain the correct
symbol table in the data section. For my tests, this initially appeared
to be an x86-only problem, but that was only because the two DLLs on x64
should have been rebased.
Signed-off-by: David Allsopp <david.allsopp@metastack.com>
Update the getconf utility to support the new flag as well as
_PC_POSIX_PERMISSIONS and _PC_POSIX_SECURITY. These were previously
unsupported, probably as an oversight.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
Long-standing problem in one of the corner cases of rename(2):
If we rename a directory a check is performed to see if newpath is
identical to oldpath or a subdir of oldpath. This check is
(accidentally? no hints anywhere in ChangeLogs or code) performed
case-insensitive for as long as we use Unicode paths and NT functions.
This leads to the problems described in
https://cygwin.com/ml/cygwin/2016-09/msg00264.html
Change this to be conditional case-sensitive as all other checks but
let's take this with a grain of salt. There may be corner-cases in
this corner-case which require to chek parts of the path always
case-insensitive. Off the top of my head I can't construct such a
case but that's no proof they don't exist :}
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
On Windows 8.1 and later, the NetUserChangePassword call apparently
doesn't accept the usual "\\server" string anymore, but requires to
use the "domain" instead, otherwise it emits en error code 1265,
ERROR_DOWNGRADE_DETECTED. Since this is accepted by pre-8.1 as well,
use the domain indiscriminately when calling NetUserChangePassword
from passwd(1).
While at it, do some minor cleanup in passwd.c.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
This patch adds pthread_getname_np and pthread_setname_np.
These were added to glibc in 2.12[1] and are also present in some form on
NetBSD and several UNIXes.
The code is based on NetBSD's implementation with changes to better match
Linux behaviour.
Implementation quirks:
* pthread_setname_np with a NULL pointer segfaults (as linux)
* pthread_setname_np returns ERANGE for names longer than 16 characters (as
linux)
* pthread_getname_np with a NULL pointer returns EFAULT (as linux)
* pthread_getname_np with a buffer length of less than 16 returns ERANGE (as
linux)
* pthread_getname_np truncates the thread name to fit the buffer length.
This guarantees success even when the default thread name is longer than 16
characters, but means there is no way to discover the actual length of the
thread name. (Linux always truncates the thread name to 16 characters)
* Changing program_invocation_short_name changes the default thread name (on
linux, it has no effect on the default thread name)
I'll leave it up to you to decide if any of these matter.
This is implemented via class pthread_attr to make it easier to add
pthread_attr_[gs]etname_np (present in NetBSD and some UNIXes) should it
ever be added to Linux (or we decide we want it anyway).
[1] https://sourceware.org/git/?p=glibc.git;a=blob;f=NEWS
POSIX requires that SSIZE_MAX have the same type as ssize_t, but
on 32-bit, we were defining it as a long even though ssize_t
resolves to an int. It also requires that SSIZE_MAX be usable
via preprocessor #if, so we can't cheat and use a cast.
If this were newlib, I'd have had to hack _intsup.h to probe the
qualities of size_t (via gcc's __SIZE_TYPE__), similar to how we
already probe the qualities of int8_t and friends, then cross our
fingers that ssize_t happens to have the same rank (most systems
do, but POSIX permits a system where they differ such as size_t
being long while ssize_t is int). Unfortunately gcc gives us
neither __SSIZE_TYPE__ nor __SSIZE_MAX__. On the other hand, our
limits.h is specific to cygwin, so we can just shortcut to the
correct results rather than being generic to all possible ABI.
Signed-off-by: Eric Blake <eblake@redhat.com>
Corinna Vinschen
Ken Brown
Mark Geisert
Corinna Vinschen
Yaakov Selkowitz
Michael Haubenwallner
Jozef Lawrynowicz
David McFarland
Jon Turney
David Allsopp
Eric Blake