This is a followup to a report back in 2011 about essentially the same issue:
https://cygwin.com/ml/cygwin/2011-04/msg00031.html
The same test program in that report demonstrates the issue, but with
kill sending any non-zero signal. To reiterate, the problem here is
POSIX compliance with respect to sending signals to zombie processes.
http://pubs.opengroup.org/onlinepubs/9699919799/functions/kill.html
claims:
Existing implementations vary on the result of a kill() with pid
indicating an inactive process (a terminated process that has not been
waited for by its parent). Some indicate success on such a call
(subject to permission checking), while others give an error of
[ESRCH]. Since the definition of process lifetime in this volume of
POSIX.1-2008 covers inactive processes, the [ESRCH] error as described
is inappropriate in this case. In particular, this means that an
application cannot have a parent process check for termination of a
particular child with kill(). (Usually this is done with the null
signal; this can be done reliably with waitpid().)
In response to the originally issue, this was fixed *specifically* for
the case of kill(pid, 0). But my reading of the above is that kill()
should return 0 in this case regardless of the signal (modulo
permissions, etc.). On Linux, for example, when calling kill with pid
of a zombie process the kernel will happily deliver the signal to the
relevant task_struct; it will just never be acted on since the task
will never run again.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
Bump GPLv2+ to GPLv3+ for some files, clarify BSD 2-clause.
Everything else stays under GPLv3+.
New Linking Exception exempts resulting executables from LGPLv3 section 4.
Add CONTRIBUTORS file to keep track of licensing.
Remove 'Copyright Red Hat Inc' comments.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
This reverts commit 0008bdea02.
This patch introduced a regression. Calling FOO=$(...) in zsh hangs
indefinitely and has to be killed forcefully.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
G++ 6.0 asserts that the "this" pointer is non-null for member
functions.
Refactor methods that check if "this" is non-null to resolve this.
winsup/cygwin/ChangeLog:
external.cc (cygwin_internal): Check for a null pinfo before calling
cmdline.
fhandler_dsp.cc (Audio::blockSize): Make static.
fhandler_dsp.cc (Audio_in): add default_buf_info.
fhandler_dsp.cc (Audio_out): Ditto.
fhandler_dsp.cc (Audio_out::buf_info): Refactor method to call
default_buf_info if dev_ is null.
fhandler_dsp.cc (Audio_in::buf_info): Ditto.
fhandler_dsp.cc (fhandler_dev_dsp::_ioctl): Call Audio_out::default_buf_info if audio_out_ is null.
fhandler_dsp.cc (fhandler_dev_dsp::_ioctl): Call Audio_in::default_buf_info if audio_in_ is null.
fhandler_process.cc (format_process_fd): Check if pinfo is null.
fhandler_process.cc (format_process_root): Ditto.
fhandler_process.cc (format_process_cwd): Ditto.
fhandler_process.cc (format_process_cmdline): Ditto.
signal.cc (tty_min::kill_pgrp): Ditto.
signal.cc (_pinfo::kill0): Ditto.
sigproc.cc (pid_exists): Ditto.
sigproc.cc (remove_proc): Ditto.
times.cc (clock_gettime): Ditto.
times.cc (clock_getcpuclockid): Ditto.
path.cc (cwdstuff::override_win32_cwd): Check if old_cwd is null.
path.cc (fcwd_access_t::Free): Factor null check of "this" out to
caller(s).
pinfo.cc (_pinfo::exists): Ditto.
pinfo.cc (_pinfo::fd): Ditto.
pinfo.cc (_pinfo::fds): Ditto.
pinfo.cc (_pinfo::root): Ditto.
pinfo.cc (_pinfo::cwd): Ditto.
pinfo.cc (_pinfo::cmdline): Ditto.
signal.cc (_pinfo::kill): Ditto.
pinfo.cc (_pinfo::commune_request): remove non-null check on "this", as
this method is only called from pinfo.cc after null checks
pinfo.cc (_pinfo::pipe_fhandler): remove non-null check on "this", as
this method is only called from pipe.cc (fhandler_pipe::open) after a null check.
Signed-off-by: Peter Foley <pefoley2@pefoley.com>
* signal.cc (sigwait): Fix return value to reflect errno in case of
error according to POSIX. Never return EINTR.
* thread.cc (pthread_kill): Return errno if sig_send failed.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
* exceptions.cc (_cygtls::call_signal_handler): Drop manipulating
thread's ss_flags here. It's not safe against longjmp.
* signal.cc (sigaltstack): Check if we're running on the alternate
stack and set ss_flags returned in oss to SS_ONSTACK.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
handler.
* cygtls.cc (_cygtls::remove): Accommodate the fact that pathbufs
has been moved from _local_storage to _cygtls.
* cygtls.h (class tls_pathbuf): Add comment to hint to gendef usage
of counters. Change type of counters to uint32_t for clarity.
Remove _cygtls as friend class.
(struct _local_storage): Move pathbufs from here...
(struct _cygtls): ...to here, allowing to access it from _sigbe.
(class san): Only define on 32 bit. Remove errno, _c_cnt and _w_cnt
members.
(san::setup): Drop parameter. Don't initialize removed members.
(san::leave): Don't set removed members.
(class myfault): Only define on 32 bit.
(myfault::faulted): Only keep implementation not taking any parameter.
Drop argument in call to sebastian.setup.
(__try/__leave/__except/__endtry): Implement to support real SEH. For
now stick to SJLJ on 32 bit.
* dcrt0.cc (dll_crt0_0): Drop 64 bit call to
exception::install_myfault_handler.
* exception.h (exception_handler): Define with EXCEPTION_DISPOSITION
as return type.
(PDISPATCHER_CONTEXT): Define as void * on 32 bit. Define as pointer
to _DISPATCHER_CONTEXT on 64 bit.
(class exception): Define separately for 32 and 64 bit.
(exception::myfault): Add handler for myfault SEH handling on 64 bit.
(exception::exception): Fix mangled method name to account for change
in type of last parameter.
(exception::install_myfault_handler): Remove.
* exceptions.cc (exception::myfault_handle): Remove.
(exception::myfault): New SEH handler for 64 bit.
* gendef (_sigbe): Set tls_pathbuf counters to 0 explicitely when
returning to the caller.
* ntdll.h: Move a comment to a better place.
(struct _SCOPE_TABLE): Define on 64 bit.
* thread.cc (verifyable_object_isvalid): Remove gcc 4.7 workaround.
* tls_pbuf.cc (tls_pbuf): Fix to accommodate new place of pathbufs.
(tls_pathbuf::destroy): Change type of loop variables to uint32_t.
* tls_pbuf.h (class tmp_pathbuf): Change type of buffer counters to
uint32_t. Accommodate new place of pathbufs.
* tlsoffsets.h: Regenerate.
* tlsoffsets64.h: Regenerate.
(telldir): Per POSIX, return -1 and set errno to EBADF, rather than
just returning 0, on invalid directory stream.
* signal.cc (sigwaitinfo): Return -1, not EFAULT, when SEGV was catched.
warnings between regparm definitions and declarations.
* smallprint.cc (__small_vswprintf): Conditionalize declaration and
setting of l_opt for only x86_64.
* spawn.cc (child_info_spawn::worker): Remove unused 'pid' variable.
* thread.cc (verifyable_object_isvalid): Temporarily define as
non-inline with gcc 4.7+, regardless of target.
(mainly in fhandler*) start fixing gcc 4.7.2 mismatch between regparm
definitions and declarations.
* gendef: Define some functions to take @ declaration to accommodate _regN
defines which use __stdcall.
* gentls_offsets: Define __regN macros as empty.
* autoload.cc (wsock_init): Remove unneeded regparm attribute.
* winsup.h (__reg1): Define.
(__reg2): Define.
(__reg3): Define.
* advapi32.cc (DuplicateTokenEx): Coerce some initializers to avoid warnings
from gcc 4.7.2.
* exceptions.cc (status_info): Declare struct to use NTSTATUS.
(cygwin_exception::dump_exception): Coerce e->ExceptionCode to NTSTATUS.
* fhandler_clipboard.cc (cygnativeformat): Redefine as UINT to avoid gcc 4.7.2
warnings.
(fhandler_dev_clipboard::read): Ditto.
* sigproc.h (sigdelayed): Make symbol globally available.
* gendef (sigdelayed): Specifically zero incyg and stacklock.
* signal.cc (sigwaitinfo): Lock _my_tls and try harder to clean up signal
information.
* exceptions.cc (sig_handle_tty_stop): Make sure that incyg is cleared when
exiting if we have no parent process. Only wait for signal_arrived.
(sigpacket::process): Make continue_now a bool. Delay sending signal_arrived
until the end. Make code more defensive to avoid calling signal handler when
stopped. Only set signal_arrived when stopped.
* sigproc.cc (sig_hold): Rename from sigCONT. Make static.
(sig_send): Accommodate sigCONT -> sig_hold rename.
(wait_sig): Ditto.
* sigproc.h (sigCONT): Delete declaration.
* fhandler_console.cc (fhandler_console::write): Use new '%0c' facility to
print characters. Change to paranoid to avoid excessive strace output.
* fhandler_tty.cc (fhandler_pty_master::accept_input): Make frequent strace
printf "paranoid" to help cut down on strace output size.
* signal.cc (sigsuspend): Add standard syscall strace output.
(sigpause): Ditto.
(pause): Ditto.
* cygtls.h (_cygtls::reset_signal_arrived): New function.
* cygserver_ipc.h (ipc_set_proc_info): Use _cygtls::ipc_set_proc_info to set
per-thread signal arrived value.
* cygthread.cc (cygthread::detach): Use per-thread signal_arrived via
set_thread_waiting.
* fork.cc (_cygtls::fixup_after_fork): Clear signal_arrived.
(_cygtls::remove): Close any signal_arrived handle when thread exists.
(_cygtls::find_tls): Remove unneeded function.
* cygtls.h: Update copyright.
(class _cygtls): Reorganize to help avoid rebuilding newlib when structure
changes.
(_cygtls::event): Delete.
(_cygtls::threadkill): Ditto.
(_cygtls::signal_waiting): Declare new bool.
(_cygtls::find_tls): Delete declaration.
(_cygtls::set_threadkill): Ditto.
(_cygtls::reset_threadkill): Ditto.
(_cygtls::set_signal_arrived): Declare new function.
(class set_thread_waiting): Declare new class.
* cygwait.cc (cw_nowait_storage): Define.
(cygwait): Set per-thread signal_arrived via set_thread_waiting. Don't
special-case _main_tls.
* cygwait.h (cw_nowait): Define.
(cw_infinite): Ditto.
(cygwait): Redefine pathological wait-only case.
* dcrt0.cc (dll_crt0_0): Remove call to now-defunct events_init().
(dll_crt0_1): Remove call to now-defunct create_signal_arrived().
* exceptions.cc: Reflect set_signal_mask() argument reordering throughout.
Remove signal mask synchronization throughout.
(events_init): Delete definition.
(mask_sync): Delete now-unneeded mask synchronization.
(set_signal_mask): Reverse order of arguments to "standard" to, from layout.
Rename "newmask" argument to "setmask". Remove debugging.
(sig_handle_tty_stop): Use cancelable_wait rather than WFMO.
(_cygtls::interrupt_setup): Don't treat "threadkill" events specially.
Conditionally set signal_arrived depending on whether the thread has created it
or not.
(sigpacket::process): Reorganize to reflect thread-specific sending of signals
which is more in line with the way it was actually supposed to work.
* fhandler_socket.cc (get_inet_addr): Use cancelable_wait rather than
IsEventSignalled to avoid potential race.
(fhandler_socket::wait_for_events): Set signal_arrived event using
set_thread_waiting().
(fhandler_socket::close): Use cygwait for the case of just waiting 10 ms for a
signal.
* fhandler_tape.cc (fhandler_dev_tape::_lock): Use cancelable_wait rather than
WFMO. Redo switch/case tests accordingly.
* fhandler_termios.cc (fhandler_termios::bg_check): Use cygwait for case of
just waiting 0 ms for a potential signal.
* fhandler_tty.cc (fhandler_pty_master::process_slave_output): Use
cancelable_wait rather than WFSO.
* fhandler_windows.cc (fhandler_windows::read): Set per-thread signal_arrived
via set_thread_waiting().
* flock.cc (lf_setlock): Ditto.
* select.cc (pselect): Ditto. Set per-thread signal_arrived using
set_thread_waiting().
* gendef: Don't special case handling of _cygtls::sig for threads.
* gentls_offsets: Use #pragma once in tlsoffsets.h.
* ntdll.h: Use #pragma once.
* poll.cc: Reflect set_signal_mask() argument reordering.
* posix_ipc.cc (ipc_mutex_lock): Use cancelable_wait rather than WFMO.
(ipc_cond_timedwait): Set perl-thread signal arrived using
set_thread_waiting().
* security.h: Use #pragma once.
* signal.cc (abort): Reflect set_signal_mask() argument reordering.
(clock_nanosleep): Ditto. Change call to cancelable_wait to properly specify
handling of cancel and interrupt.
(sigwaitinfo): Remove handling of per-thread event in favor of per-thread
signal_arrived. Use cancelable_wait rather than WFSO.
* sigproc.cc (signal_arrived): Delete definition.
(create_signal_arrived): Ditto.
* sigproc.h (signal_arrived): Delete declaration.
(set_signal_mask): Avoid defining as a "C" function. Don't conditionally
declare.
(create_signal_arrived): Delete declaration.
* syscalls.cc (rename): Use cygwait() rather than WFSO.
* thread.h (fast_mutex::lock): Use cw_infinite rather than LARGE_NULL.
* wait.cc (wait4): Ditto.
* thread.cc (pthread_mutex::lock): Ditto.
(pthread::join): Ditto.
(semaphore::_wait): Ditto.
(pthread_kill): Remove set_threadkill() accommodation.
* tlsoffsets.h: Regenerate.
why -fomit-frame-pointer doesn't work right for passwd.o and path.o. Add
-static to link command line for cygwin0.dll.
* fhandler_disk_file.cc (fhandler_disk_file::facl): Reorganize slightly to
silence compiler warning when compiling with -fstack-check.
* net.cc (inet_ntop6): Initialize structure members to silence compiler warning
when compiling with -fstack-check.
* pseudo-reloc.cc (_pei386_runtime_relocator): Make this a C function. Detect
NULL u.
* winsup.h (_pei386_runtime_relocator): Declare this as extern "C".
* lib/_cygwin_crt0_common.cc (_pei386_runtime_relocator): Call with NULL
argument.
* signal.cc (sigaction_worker): Eliminate last argument. Let callers report
their own strace info. Regparmize.
(sigaction): Reflect sigaction_worker changes.
(siginterrupt): Ditto.
* exceptions.cc: Update copyright.
information.
* exceptions.cc (_cygtls::inside_kernel): Modernize comment. Consider
executing a DLL from the Wow64 directory as being "in the kernel".
(_cygtls::call_signal_handler): For now, only deal with main_tls signals if
main_tls is known to be executing in the cygwin DLL. To more closely emulate
linux, consider the operation to be restartable if not executing in the main
thread.
* globals.cc (windows_system_directory): Remove NO_COPY.
(windows_system_directory_length): Ditto.
(system_wow64_directory): New variable.
(system_wow64_directory_length): Ditto.
* select.cc (cygwin_select): Don't issue a EINTR on non-main threads since that
seems to be what Linux does. Add missing break to signal case/switch.
(select_stuff::wait): Don't issue a EINTR on non-main threads since that seems
to be what Linux does. Remove now-unneeded accommodation for
WAIT_IO_COMPLETION. Add a comment.
* sigproc.h (cygwait): Ditto. Don't return if signal_received noticed and it's
not the main thread.
* signal.cc (sigprocmask): Add standard syscall debug stuff.
* thread.cc (pthread_sigmask): Ditto.
(munlock): Ditto.
(posix_madvise): Ditto.
* signal.cc: Remove obsolete sigcatchers stuff throughout.
(sigaction_worker): Add function name parameter and use it to show standard
syscall return value debugging output. Also add fault protection.
(sigaction): Accommodate extra argument to sigaction_worker.
(siginterrupt): Ditto.
* syscalls.cc (read): Remove obsolete sigcatchers stuff.
(readv): Ditto.
Throughout, change syscalls to report on return values using new %R format
option.
* smallprint.cc (__small_vsprintf): Add parsing for %R to report on return
values and possible errno from syscalls.
* errno.cc (errmap): Add PRIVILEGE_NOT_HELD.
* fhandler_tty.cc (fhandler_pty_master::setup): When creating a thread use
shorter name to reduce debuggging output.
* select.cc (start_thread_pipe): Ditto.
(start_thread_serial): Ditto.
(start_thread_socket): Ditto.
(start_thread_mailslot): Ditto.
* sigproc.cc (talktome): Ditto.
have been terminated prior to setting flag.
* signal.cc (sigwaitinfo): Zero event before closing to signal other threads
that it is no longer available.
Throughout rename _PROC_* to _CH_*.
* child_info.h: Include "pinfo.h".
(child_info_types): Rename _PROC_* -> _CH_* to avoid confusion with similarly
named constants.
(_PROC_*): Delete unneeded aliases.
(PROC_*): Ditto.
(CURR_CHILD_INFO_MAGIC): Ditto.
(cchildren): Define using "pinfo_minimal".
(child_info::set_saw_ctrl_c): Move to
(child_info_spawn::set_saw_ctrl_c): Here.
(child_info_spawn::lock): New field.
(child_info_spawn::hExeced): Ditto.
(child_info_spawn::ev): Ditto.
(child_info_spawn::~child_info_spawn): Move to sigproc.cc.
(child_info_spawn::child_info_spawn): Ditto.
(child_info_spawn::cleanup): Declare new function.
(child_info_spawn::set_saw_ctrl_c): Move to this class. Set flag only when
execed and return true when we have set the flag.
(child_info_spawn::child_info_spawn::signal_myself_exited): New function.
(child_info_spawn::wait_for_myself): Ditto.
(child_info_spawn::has_execed_cygwin): Ditto.
(child_info_spawn::has_execed): Ditto. Replaces "hExeced" test.
(child_info_spawn::operator HANDLE&): New operator.
(child_info_spawn::worker): Define old "spawn_guts" as class member.
(ch_spawn): Declare.
(have_execed): Define.
(have_execed_cygwin): Ditto.
* cygheap.h: Update comment.
* dcrt0.cc (get_cygwin_startup_info): Use _CH_* enums.
(child_info_spawn::handle_spawn): Ditto.
(dll_crt0_0): Ditto.
(multiple_cygwin_problem): Ditto.
* exceptions.cc (chExeced): Delete obsolete declaration.
(ctrl_c_handler): Reference set_saw_ctrl_c via new ch_spawn global.
* globals.cc (hExeced): Delete.
* pinfo.cc (pinfo::thisproc): Refer to cygheap as ::cygheap for consistency in
handle naming when -DDEBUGGING.
(pinfo::init): Accommodate case where myself.h is known but h0 is passed in.
(pinfo::pinfo): New constructor for setting up a pinfo passed in by previous
exec'or.
(pinfo::proc_waiter): Don't handle subprocess if we're in the process of
exiting due to an exec of a cygwin process. Don't close rd_proc_pipe here.
Close it when we actually are finished with the process. Use new
ch_spawn.signal_myself_exited function to let exec stub know that subprocess
has exited.
(pinfo::wait): Clarify debugging output.
(pinfo::release): Use "close_h" to close all handles to avoid races.
(winpids::add): Assume that elements of the array do not need to be zeroed and
are properly initialized or suffer problems on pinfo::release. Don't close
hProcess since release does that now.
* pinfo.h: Update comment.
(pinfo_minimal): Move some elements from pinfo here so that child_info_spawn
can use them.
(pinfo): Inherit from pinfo_minimal.
(pinfo::pinfo): Modify to accommodate new pinfo_minimal.
(pinfo::allow_remove): New function.
* sigproc.cc (proc_subproc): Use boolean values for true/false. Implement
PROC_EXEC_CLEANUP.
(proc_terminate): Set ppid = 1 since the procs list will only be iterated when
the process has not execed. Don't do any cleanup here since it is now handled
in pinfo::release.
(sigproc_init): Initialize sync_proc_subproc earlier.
(child_info::child_info): Assume that all important fields are properly
initialized and avoid memset().
(child_info_spawn::child_info_spawn): Specifically test for execing and then
set up appropriate fields in the struct.
(child_info_spawn::cleanup): Define new function.
(child_info_spawn::record_children): Specifically test for being execed here.
Fill in pinfo_minimal part of children array.
(child_info_spawn::reattach_children): Use constructor to duplicate information
for previous exec'or. Add more debugging output.
(remove_proc): Force deletion of thread when exiting due to exec. Rely on
pinfo::cleanup in release.
* sigproc.h (PROC_EXEC_CLEANUP): New enum.
(PROC_DETACHED_CHILD): Delete.
* spawn.cc (chExeced): Delete.
(child_info_spawn::worker): Rename from spawn_guts. Use elements of
child_info_spawn throughout rather than ch.whatever. Use ::cygheap to refer to
global rather than element of child_info. Use wait_for_myself() rather than
waitpid(). Call child_info_spawn::cleanup on function return.
(spawnve): Reflect movement of spawn_guts functionality into
child_info_spawn::worker.
* syscalls.cc (popen): Ditto.
* winsup.h (spawn_guts): Delete declaration.
* posix.sgml (std-notimpl): Move clock_nanosleep from here...
(std-susv4): ... to here.
(std-notes): Note limitations of clock_nanosleep.
* signal.cc (clock_nanosleep): Renamed from nanosleep, adding clock_id
and flags arguments and changing return values throughout.
Improve checks for illegal rqtp values. Add support for
CLOCK_MONOTONIC and TIMER_ABSTIME.
(nanosleep): Rewrite in terms of clock_nanosleep.
(sleep): Ditto.
(usleep): Ditto.
* thread.cc: Mark clock_nanosleep in list of cancellation points.
* include/cygwin/version.h (CYGWIN_VERSION_API_MINOR): Bump.
in PID_EXITED state. Report pid 0 when pid does not exist rather than pid -1.
Make debug output reflect actual function call.
* sigproc.cc (stopped_or_terminated): Set process state to reaped when we've
finished waiting for it.
* include/sys/cygwin.h (PID_REAPED): New enum.
* spawn.cc (spawn_guts): Set a flag when a process is not a cygwin process.
* fhandler_tty.cc (fhandler_tty_slave::init): Remove previous change. Try a
different method to determine when we should become the process group owner.
* signal.cc (kill0): Remove archaic code which dealt with never-set flag.
Erik Bray
Corinna Vinschen
Peter Foley
Christopher Faylor
Yaakov Selkowitz
Eric Blake