This adds _hurd_sigstate_set_global_rcv used by libpthread to enable
POSIX-confirming behavior of signals on a per-thread basis.
This also provides a sigstate destructor _hurd_sigstate_delete, and a
global process signal state, which needs to be locked and check when
global disposition is enabled, thus the addition of _hurd_sigstate_lock
_hurd_sigstate_actions _hurd_sigstate_pending _hurd_sigstate_unlock helpers.
This also updates all the glibc code accordingly.
This also drops support for get_int(INIT_SIGMASK), which did not make sense
any more since we do not have a single signal thread any more.
During fork/spawn, this also reinitializes the child global sigstate's
lock. That cures an issue that would very rarely cause a deadlock in the
child in fork, tries to unlock ss' critical section lock at the end of
fork. This will typically (always?) be observed in /bin/sh, which is not
surprising as that is the foremost caller of fork.
To reproduce an intermediate state, add an endless loop if
_hurd_global_sigstate is locked after __proc_dostop (cast through
volatile); that is, while still being in the fork's parent process.
When that triggers (use the libtool testsuite), the signal thread has
already locked ss (which is _hurd_global_sigstate), and is stuck at
hurdsig.c:685 in post_signal, trying to lock _hurd_siglock (which the
main thread already has locked and keeps locked until after
__task_create). This is the case that ss->thread == MACH_PORT_NULL, that
is, a global signal. In the main thread, between __proc_dostop and
__task_create is the __thread_abort call on the signal thread which would
abort any current kernel operation (but leave ss locked). Later in fork,
in the parent, when _hurd_siglock is unlocked in fork, the parent's
signal thread can proceed and will unlock eventually the global sigstate.
In the client, _hurd_siglock will likewise be unlocked, but the global
sigstate never will be, as the client's signal thread has been configured
to restart execution from _hurd_msgport_receive. Thus, when the child
tries to unlock ss' critical section lock at the end of fork, it will
first lock the global sigstate, will spin trying to lock it, which can
never be successful, and we get our deadlock.
Options seem to be:
* Move the locking of _hurd_siglock earlier in post_signal -- but that
may generally impact performance, if this locking isn't generally
needed anyway?
On the other hand, would it actually make sense to wait here until we
are not any longer in a critical section (which is meant to disable
signal delivery anyway (but not for preempted signals?))?
* Clear the global sigstate in the fork's child with the rationale that
we're anyway restarting the signal thread from a clean state. This
has now been implemented.
Why has this problem not been observed before Jérémie's patches? (Or has
it? Perhaps even more rarely?) In _S_msg_sig_post, the signal is now
posted to a *global receiver thread*, whereas previously it was posted to
the *designated signal-receiving thread*. The latter one was in a
critical section in fork, so didn't try to handle the signal until after
leaving the critical section? (Not completely analyzed and verified.)
Another question is what the signal is that is being received
during/around the time __proc_dostop executes.
This should not change the current behavior, although this fixes a few
minor bugs which were made apparent in the process of global signal
disposition work:
- Split into more functions
- Scope variables more restrictively
- Split out inner functions
- refactor check_pending_signals
- make sigsuspend POSIX-conformant.
- fix uninitialized act value.
* sysdeps/mach/hurd/i386/intr-msg.h (INTR_MSG_TRAP): Make
_hurd_intr_rpc_msg_about_to global point to start of controlled
assembly snippet. Make it check canceled flag.
* hurd/hurdsig.c (_hurdsig_abort_rpcs): Only mutate thread if it passed
the _hurd_intr_rpc_msg_about_to point.
* hurd/intr-msg.c (_hurd_intr_rpc_mach_msg): Remove comment on mutation
issue, remove cancel flag check.
Seeing a server not able to get interrupted for 3s is not so surprising when
e.g. a lot of writes are happening. 1 minute allows to actually notice the
issue and be able to debug it.
* hurd/hurdsig.c (_hurd_interrupted_rpc_timeout): Set to 60000.
Exec needs that mach_setup_thread does *not* set up TLS since it works on
another task, so we have to split this into mach_setup_tls.
* mach/mach.h (__mach_setup_tls, mach_setup_tls): Add prototypes.
* mach/setup-thread.c (__mach_setup_thread): Move TLS setup to...
(__mach_setup_tls): ... new function.
(mach_setup_tls): New alias.
* hurd/hurdsig.c (_hurdsig_init): Call __mach_setup_tls after
__mach_setup_thread.
* sysdeps/mach/hurd/profil.c (update_waiter): Likewise.
* sysdeps/mach/hurd/setitimer.c (setitimer_locked): Likewise.
* mach/Versions [libc] (mach_setup_tls): Add symbol.
* sysdeps/mach/hurd/i386/libc.abilist (mach_setup_tls): Likewise.
* hurd/Makefile (routines): Add hurdlock.
* hurd/Versions (GLIBC_PRIVATE): Added new entry to export the above
interface.
(HURD_CTHREADS_0.3): Remove __libc_getspecific.
* hurd/hurdpid.c: Include <lowlevellock.h>
(_S_msg_proc_newids): Use lll_wait to synchronize.
* hurd/hurdsig.c: (reauth_proc): Use __mutex_lock and __mutex_unlock.
* hurd/setauth.c: Include <hurdlock.h>, use integer for synchronization.
* mach/Makefile (lock-headers): Remove machine-lock.h.
* mach/lock-intern.h: Include <lowlevellock.h> instead of
<machine-lock.h>.
(__spin_lock_t): New type.
(__SPIN_LOCK_INITIALIZER): New macro.
(__spin_lock, __spin_unlock, __spin_try_lock, __spin_lock_locked,
__mutex_init, __mutex_lock_solid, __mutex_unlock_solid, __mutex_lock,
__mutex_unlock, __mutex_trylock): Use lll to implement locks.
* mach/mutex-init.c: Include <lowlevellock.h> instead of <cthreads.h>.
(__mutex_init): Initialize with lll.
* manual/errno.texi (EOWNERDEAD, ENOTRECOVERABLE): New errno values.
* sysdeps/mach/Makefile: Add libmachuser as dependencies for libs
needing lll.
* sysdeps/mach/hurd/bits/errno.h: Regenerate.
* sysdeps/mach/hurd/cthreads.c (__libc_getspecific): Remove function.
* sysdeps/mach/hurd/bits/libc-lock.h: Remove file.
* sysdeps/mach/hurd/setpgid.c: Include <lowlevellock.h>.
(__setpgid): Use lll for synchronization.
* sysdeps/mach/hurd/setsid.c: Likewise with __setsid.
* sysdeps/mach/bits/libc-lock.h: Include <tls.h> and <lowlevellock.h>
instead of <cthreads.h>.
(_IO_lock_inexpensive): New macro
(__libc_lock_recursive_t, __rtld_lock_recursive_t): New structures.
(__libc_lock_self0): New declaration.
(__libc_lock_owner_self): New macro.
(__libc_key_t): Remove type.
(_LIBC_LOCK_INITIALIZER): New macro.
(__libc_lock_define_initialized, __libc_lock_init, __libc_lock_fini,
__libc_lock_fini_recursive, __rtld_lock_fini_recursive,
__libc_lock_lock, __libc_lock_trylock, __libc_lock_unlock,
__libc_lock_define_initialized_recursive,
__rtld_lock_define_initialized_recursive,
__libc_lock_init_recursive, __libc_lock_trylock_recursive,
__libc_lock_lock_recursive, __libc_lock_unlock_recursive,
__rtld_lock_initialize, __rtld_lock_trylock_recursive,
__rtld_lock_lock_recursive, __rtld_lock_unlock_recursive
__libc_once_define, __libc_mutex_unlock): Reimplement with lll.
(__libc_lock_define_recursive, __rtld_lock_define_recursive,
_LIBC_LOCK_RECURSIVE_INITIALIZER, _RTLD_LOCK_RECURSIVE_INITIALIZER):
New macros.
Include <libc-lockP.h> to reimplement libc_key* with pthread_key*.
* hurd/hurdlock.c: New file.
* hurd/hurdlock.h: New file.
* mach/lowlevellock.h: New file
This gets rid of a lot of kludge and gets closer to other ports.
* hurd/Makefile (headers): Remove threadvar.h.
(inline-headers): Remove threadvar.h.
* hurd/Versions (GLIBC_2.0: Remove __hurd_sigthread_stack_base,
__hurd_sigthread_stack_end, __hurd_sigthread_variables,
__hurd_threadvar_max, __hurd_errno_location.
(HURD_CTHREADS_0.3): Add pthread_getattr_np, pthread_attr_getstack.
* hurd/hurd/signal.h: Do not include <hurd/threadvar.h>.
(_hurd_self_sigstate): Use THREAD_SELF to get _hurd_sigstate.
(_HURD_SIGNAL_H_EXTERN_INLINE): Use THREAD_SELF to get _hurd_sigstate,
unless TLS is not initialized yet, in which case we do not need a
critical section yet anyway.
* hurd/hurd/threadvar.h: Include <tls.h>, do not include
<machine-sp.h>.
(__hurd_sigthread_variables, __hurd_threadvar_max): Remove variables
declarations.
(__hurd_threadvar_index): Remove enum.
(_HURD_THREADVAR_H_EXTERN_INLINE): Remove macro.
(__hurd_threadvar_location_from_sp,__hurd_threadvar_location): Remove
inlines.
(__hurd_reply_port0): New variable declaration.
(__hurd_local_reply_port): New macro.
* hurd/hurdsig.c (__hurd_sigthread_variables): Remove variable.
(interrupted_reply_port_location): Add thread_t parameter. Use it
with THREAD_TCB to access thread-local variables.
(_hurdsig_abort_rpcs): Pass ss->thread to
interrupted_reply_port_location.
(_hurd_internal_post_signal): Likewise.
(_hurdsig_init): Use presence of cthread_fork instead of
__hurd_threadvar_stack_mask to start signal thread by hand.
Remove signal thread threadvar initialization.
* hurd/hurdstartup.c: Do not include <hurd/threadvar.h>
* hurd/sigunwind.c: Include <hurd/threadvar.h>
(_hurdsig_longjmp_from_handler): Use __hurd_local_reply_port instead
of threadvar.
* sysdeps/mach/hurd/Versions (libc.GLIBC_PRIVATE): Add
__libc_lock_self0.
(ld.GLIBC_2.0): Remove __hurd_sigthread_stack_base,
__hurd_sigthread_stack_end, __hurd_sigthread_variables.
(ld.GLIBC_PRIVATE): Add __libc_lock_self0.
* sysdeps/mach/hurd/cthreads.c: Add __libc_lock_self0.
* sysdeps/mach/hurd/dl-sysdep.c (errno, __hurd_sigthread_stack_base,
__hurd_sigthread_stack_end, __hurd_sigthread_variables, threadvars,
__hurd_threadvar_stack_offset, __hurd_threadvar_stack_mask): Do not
define variables.
* sysdeps/mach/hurd/errno-loc.c: Do not include <errno.h> and
<hurd/threadvar.h>.
[IS_IN(rtld)] (rtld_errno): New variable.
[IS_IN(rtld)] (__errno_location): New weak function.
[!IS_IN(rtld)]: Include "../../../csu/errno-loc.c".
* sysdeps/mach/hurd/errno.c: Remove file.
* sysdeps/mach/hurd/fork.c: Include <hurd/threadvar.h>
(__fork): Remove THREADVAR_SPACE macro and its use.
* sysdeps/mach/hurd/i386/init-first.c (__hurd_threadvar_max): Remove
variable.
(init): Do not initialize threadvar.
* sysdeps/mach/hurd/i386/libc.abilist (__hurd_threadvar_max): Remove
symbol.
* sysdeps/mach/hurd/i386/sigreturn.c (__sigreturn): Use
__hurd_local_reply_port instead of threadvar.
* sysdeps/mach/hurd/i386/tls.h (tcbhead_t): Add reply_port and
_hurd_sigstate fields.
(HURD_DESC_TLS, __LIBC_NO_TLS, THREAD_TCB): New macro.
* sysdeps/mach/hurd/i386/trampoline.c: Remove outdated comment.
* sysdeps/mach/hurd/libc-lock.h: Do not include <hurd/threadvar.h>.
(__libc_lock_owner_self): Use &__libc_lock_self0 and THREAD_SELF
instead of threadvar.
* sysdeps/mach/hurd/libc-tsd.h: Remove file.
* sysdeps/mach/hurd/mig-reply.c (GETPORT, reply_port): Remove macros.
(use_threadvar, global_reply_port): Remove variables.
(__hurd_reply_port0): New variable.
(__mig_get_reply_port): Use __hurd_local_reply_port and
__hurd_reply_port0 instead of threadvar.
(__mig_dealloc_reply_port): Likewise.
(__mig_init): Do not initialize threadvar.
* sysdeps/mach/hurd/profil.c: Fix comment.
Add net/ethernet.h net/if_arp.h net/if_ether.h net/if_ppp.h
net/route.h.
* hurd/report-wait.c (describe_number): Use __stpcpy to prepend
flavor to description only when flavor is not NULL.
* hurd/hurdsig.c (signal_allowed): Unlock _hurd_dtable_lock
mutex after SIGIO/SIGURG lookup loop.
ignore a signal that came from a machine exception, treat it as a
fatal core-dump signal instead.
Reported by Samuel Thibault <samuel.thibault@ens-lyon.org>.
Change argument type from int to intptr_t.
* locale/global-locale.c (__libc_tsd_LOCALE_data): Conditionalize the
initializer on [! _HURD_THREADVAR_H] (bad kludge).
* sysdeps/mach/hurd/i386/init-first.c (init): Initialize
_HURD_THREADVAR_LOCALE slot to &_nl_global_locale.
* hurd/hurdsig.c (_hurdsig_init): Likewise. Zero other slots.
Reported by Jon Arney <jarney1@cox.net>.
2002-02-23 Roland McGrath <roland@frob.com>
* hurd/hurd/threadvar.h (__hurd_threadvar_location): Add __THROW to
declaration.
(__hurd_errno_location): Function removed.
* hurd/hurdsig.c (_hurdsig_init): Remove a useless line of code.
2001-07-07 Roland McGrath <roland@frob.com>
* hurd/hurdsig.c (_hurd_thread_sigstate): Use MACH_PORT_NULL, not 0.
2001-07-06 Paul Eggert <eggert@twinsun.com>
* manual/argp.texi: Remove ignored LGPL copyright notice; it's
not appropriate for documentation anyway.
* manual/libc-texinfo.sh: "Library General Public License" ->
"Lesser General Public License".
2001-07-06 Andreas Jaeger <aj@suse.de>
* All files under GPL/LGPL version 2: Place under LGPL version
2.1.
2001-01-24 Mark Kettenis <kettenis@gnu.org>
* hurd/hurdsig.c (_hurdsig_getenv): Remove spurious innermost
declaration of value such that we actually return the value of the
environment variable.
2000-08-22 Mark Kettenis <kettenis@gnu.org>
* hurd/hurdsig.c: Rearrange headers a bit.
(_hurdsig_init): Block until _hurd_msgport_thread is initialized
when cthreads is being used.
* hurd/hurdsig.c (_hurdsig_init): If __hurd_threadvar_stack_mask is
nonzero, use cthread_fork to create the signal thread.
* hurd/msgportdemux.c (_hurd_msgport_receive): Initialize
_hurd_msgport_thread here (to self).
* sysdeps/mach/hurd/fork.c (__fork): When __hurd_sigthread_stack_end
is zero, instead compute child signal thread's starting SP from parent
signal thread's current SP and the threadvar_stack variables.
* hurd/Versions (GLIBC_2.1.3): Add cthread_fork, cthread_detach.
These are now referenced weakly by _hurdsig_init.
* hurd/report-wait.c (_S_msg_report_wait): Fix typo:
&_hurd_itimer_thread not &_hurd_msgport_thread.
1999-10-01 Roland McGrath <roland@baalperazim.frob.com>
* hurd/hurdfchdir.c (_hurd_change_directory_port_from_fd): Rewrite
without HURD_DPORT_USE to clean up warnings.
* hurd/dtable.c (get_dtable_port): Likewise.
* hurd/hurdioctl.c (rectty_dtable): Renamed to install_ctty.
(install_ctty): Do the changing of the cttyid port cell here, inside
the critical section while we holding the dtable lock.
(_hurd_setcttyid, tiocsctty, tiocnotty): Use that instead of changing
the port cell and calling rectty_dtable.
(_hurd_locked_install_cttyid): New function, split out of install_ctty.
(install_ctty): Use it inside a critical section, with the lock held.
* sysdeps/mach/hurd/setsid.c (__setsid): Use
_hurd_locked_install_cttyid to effect the cttyid and dtable changes
after proc_setsid, having held the dtable lock throughout.
* hurd/dtable.c (ctty_new_pgrp): With the dtable lock held, check the
cttyid port for null and bail out early if so. The dtable lock
serializes us after any cttyid change and its associated dtable update.
* sysdeps/mach/_strerror.c: Include <libintl.h>.
1999-07-19 Roland McGrath <roland@baalperazim.frob.com>
* hurd/hurdsig.c (_hurd_internal_post_signal): If a
hurd_signal_preemptor matches but its `preemptor' field is null, use
its `handler' field directly. This is to comply with behavior
documented in <hurd/sigpreempt.h>.
