different from what has been offered in libc_r (the one spotted in the
original PR which is found in libthr has already been removed by David's
commit, which is rev. 1.44 of lib/libthr/thread/thr_private.h):
- Use POSIX standard prototype for ttyname_r, which is,
int ttyname_r(int, char *, size_t);
Instead of:
char *ttyname_r(int, char *, size_t);
This is to conform IEEE Std 1003.1, 2004 Edition [1].
- Since we need to use standard errno for return code, include
errno.h in ttyname.c
- Update ttyname(3) implementation according to reflect the API
change.
- Document new ttyname_r(3) behavior
- Since we already make use of a thread local storage for
ttyname(3), remove the BUGS section.
- Remove conflicting ttyname_r related declarations found in libc_r.
Hopefully this change should not have changed the API/ABI, as the ttyname_r
symbol was never introduced before the last unistd.h change which happens a
couple of days before.
[1] http://www.opengroup.org/onlinepubs/009695399/functions/ttyname.html
Requested by: Tom McLaughlin <tmclaugh sdf lonestar org>
Through PR: threads/76938
Patched by: Craig Rodrigues <rodrigc crodrigues org> (with minor changes)
Prompted by: mezz@
not save (restore) the global pointer (GP) in the jmpbuf in setjmp
(longjmp) because it's not needed in general. GP is considered a
scratch register at callsites and hence is always restored after a
call (when it's possible that the call resolves to a symbol in a
different loadmodule; otherwise GP does not have to be saved and
restored at all), including calls to setjmp/longjmp. There's just
one problem with this now that we use setjmp/longjmp for context
switching: A new context must have GP defined properly for the
thread's entry point. This means that we need to put GP in the
jmpbuf and consequently that we have to restore is in longjmp.
This automaticly requires us to save it as well.
When setjmp/longjmp isn't used for context switching, this can be
reverted again.
because we have 2 stacks per thread: the regular downward
memory stack and the irregular upward register stack. This
implementation lets both stacks grow toward each other. An
alternative scheme is to have them grow away from each other.
The alternate scheme has the advantage that both stack grow
toward guard pages. Since libc_r is virtually dead and we
really want the *context stuff for thread switching, we don't
try to be perfect, just functional.
by filling in the jump table.
Convert uses of pthread routines within libc_r to use the internal
versions (_pthread_foo instead of pthread_foo).
Remove a couple of globals from application namespace.
to/from a ucontext when a thread is interrupted by a signal.
This will be removed when a proper fix is made in the kernel
to save/restore the FP state without breaking the ABI.
at file flags and replace it with functions that will avoid null
pointer checks.
MFC to be done by archie ;-)
PR: 42100
Reviewed by: archie, robert
MFC after: 3 days
and pthread_resume_all_np(). These suspend and resume all threads except
the current thread, respectively. The existing functions pthread_single_np()
and pthread_multi_np(), which formerly had no effect, now exhibit the same
behaviour and pthread_suspend_all_np() and pthread_resume_all_np(). These
functions have been added mostly for the native java port.
Don't allow the uthread kernel pipe to use the same descriptors as
stdio. Mostily submitted by Oswald Buddenhagen <ossi@kde.org>.
Correct some minor style nits.
of an alternate signal stack for handling signals. Let the kernel
send signals on the stack of the current thread and teach the threads
signal handler how to deliver signals to the current thread if it
needs to. Also, always store a threads context as a jmp_buf. Eventually
this will change to be a ucontext_t or mcontext_t.
Other small nits. Use struct pthread * instead of pthread_t in internal
library routines. The threads code wants struct pthread *, and pthread_t
doesn't necessarily have to be the same.
Reviewed by: jasone
return address when modifying a jmp_buf to create a new thread context.
Also set t12 with the return address.
This should fix libc_r on alpha.
With much detective work by: Bernd Walter <ticso@cicely.de>
kernel #defines to figure out where the stack is located. This stops
libc_r from exploding when the kernel is compiled with a different
KVM size. IMHO this is all kinda bogus, it would be better to just
check %esp and work from that.
- uthread_signal.c; libc_r does not wrap signal() since 1998/04/29.
- uthread_attr_setprio.c; it was never connected to the build, and
pthread_attr_setprio() does not exist in POSIX.
- uthread_sigblock.c and uthread_sigsetmask.c; these were no-ops
bloating libc_r's space.
pthread_private.h:
- Removed prototypes of non-syscalls: send().
- Removed prototypes of unused syscalls: sigpending(), sigsuspend(),
and select().
- Fixed prototype of fork().
- MFS: Fixed prototypes of <sys/socket.h> syscalls.
Reviewed by: deischen
Approved by: deischen, jasone
be malloc()ed, but they are now allocated using mmap(), just as the
default-size stacks are. A separate cache of stacks is kept for
non-default-size stacks.
Collaboration with: deischen
atomically:
1) Search _thread_list for the thread to join.
2) Search _dead_list for the thread to join.
3) Set the running thread as the joiner.
While we're at it, fix a race in the case where multiple threads try to
join on the same thread. POSIX says that the behavior of multiple joiners
is undefined, but the fix is cheap as a result of the other fix.
keep track of a joiner. POSIX only supports a single joiner, so this
simplification is acceptable.
At the same time, make sure to mark a joined thread as detached so that
its resources can be freed.
Reviewed by: deischen
PR: 24345
application to provide locking for I/O operations. This doesn't
break any of my tests, but the old behavior can be restored by
compiling with _FDLOCKS_ENABLED. This will eventually be removed
when it is obvious it does not cause any problems.
Remove most of flockfile implementation, with the exception of
flockfile_debug.
Make error messages more informational (submitted by Mike Heffner
<spock@techfour.net>, who's now known as mikeh@FreeBSD.org).
Add another check for thread library initialization (jdp, we
really need a way to get _thread_init called at program start
before any constructors are run).
_foo - wrapped system call
foo - weak definition to _foo
and for cancellation points:
_foo - wrapped system call
__foo - enter cancellation point, call _foo(), leave
cancellation point
foo - weak definition to __foo
Change use of global _thread_run to call a function to get the
currently running thread.
Make all pthread_foo functions weak definitions to _pthread_foo,
where _pthread_foo is the implementation. This allows an application
to provide its own pthread functions.
Provide slightly different versions of pthread_mutex_lock and
pthread_mutex_init so that we can tell the difference between
a libc mutex and an application mutex. Threads holding mutexes
internal to libc should never be allowed to exit, call signal
handlers, or cancel.
Approved by: -arch
the kernel to (re)use the alternate signal stack. In this
case, we don't return normally from the signal handler,
so the kernel still thinks we are using the signal stack.
The fixes a nasty bug where the signal handler can start
fiddling with the stack of a thread while the handler is
actually running on the same stack.
MFC candidate
file descriptors needing to be polled (Doh!). Reported
by Dan Nelson <dnelson@emsphone.com>.
Don't install and start the scheduling timer until the
first thread is created. This prevents the overhead of
having a periodic scheduling signal in a single threaded
program. Reported by Dan Nelson <dnelson@emsphone.com>.
Allow builtin longjmps out of application installed
signal handlers without the need perform any post-handler
cleanup:
o Change signal handling to save the threads interrupted
context on the stack. The threads current context is
now always stored in the same place (in the pthread).
If and when a signal handler returns, the interrupted
context is copied back to the storage area in the pthread.
o Before calling invoking a signal handler for a thread,
back the thread out of any internal waiting queues
(mutex, CV, join, etc) to which it belongs.
Rework uthread_info.c a bit to make it easier to change
the format of a thread dump.
Use an alternal signal stack for the thread library's
signal handler. This allows us to fiddle with the main
threads stack without fear of it being in use.
Reviewed by: jasone
thread switches should be on par with that under scheduler
activations.
o Timing is achieved through the use of a fixed interval
timer (ITIMER_PROF) to count scheduling ticks instead
of retrieving the time-of-day upon every thread switch
and calculating elapsed real time.
o Polling for I/O readiness is performed once for each
scheduling tick instead of every thread switch.
o The non-signal saving/restoring versions of setjmp/longjmp
are used to save and restore thread contexts. This may
allow the removal of _THREAD_SAFE macros from setjmp()
and longjmp() - needs more investigation.
Change signal handling so that signals are handled in the
context of the thread that is receiving the signal. When
signals are dispatched to a thread, a special signal handling
frame is created on top of the target threads stack. The
frame contains the threads saved state information and a new
context in which the thread can run. The applications signal
handler is invoked through a wrapper routine that knows how
to restore the threads saved state and unwind to previous
frames.
Fix interruption of threads due to signals. Some states
were being improperly interrupted while other states were
not being interrupted. This should fix several PRs.
Signal handlers, which are invoked as a result of a process
signal (not by pthread_kill()), are now called with the
code (or siginfo_t if SA_SIGINFO was set in sa_flags) and
sigcontext_t as received from the process signal handler.
Modify the search for a thread to which a signal is delivered.
The search algorithm is now:
o First thread found in sigwait() with signal in wait mask.
o First thread found sigsuspend()'d on the signal.
o Current thread if signal is unmasked.
o First thread found with signal unmasked.
Collapse machine dependent support into macros defined in
pthread_private.h. These should probably eventually be moved
into separate MD files.
Change the range of settable priorities to be compliant with
POSIX (0-31). The threads library uses higher priorities
internally for real-time threads (not yet implemented) and
threads executing signal handlers. Real-time threads and
threads running signal handlers add 64 and 32, respectively,
to a threads base priority.
Some other small changes and cleanups.
PR: 17757 18559 21943
Reviewed by: jasone
not have a user-supplied signal handler, when a signal is delivered, one
thread will receive the signal, and then the code reverts to having no
signal handler for the signal. This can leave the other sigwait()ing
threads stranded permanently if the signal is later ignored, or can result
in process termination when the process should have delivered the signal to
one of the threads in sigwait().
To fix this problem, maintain a count of sigwait()ers for each signal that
has no default signal handler. Use the count to correctly install/uninstall
dummy signal handlers.
Reviewed by: deischen
not allowed to return EINTR, but use of pthread_suspend_np() could cause
EINTR to be returned. To fix this, restructure pthread_suspend_np() so that
it does not interrupt a thread that is waiting on a mutex or condition, and
keep enough state around that pthread_resume_np() can fix things up
afterwards.
Reviewed by: deischen
