1 /* Copyright (C) 1991, 92, 93, 94, 95, 96, 1996 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Library General Public License as
6 published by the Free Software Foundation; either version 2 of the
7 License, or (at your option) any later version.
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Library General Public License for more details.
14 You should have received a copy of the GNU Library General Public
15 License along with the GNU C Library; see the file COPYING.LIB. If
16 not, write to the Free Software Foundation, Inc., 675 Mass Ave,
17 Cambridge, MA 02139, USA. */
22 #include <hurd/signal.h>
23 #include <cthreads.h> /* For `struct mutex'. */
25 #include "hurdfault.h"
26 #include "hurdmalloc.h" /* XXX */
28 const char *_hurdsig_getenv (const char *);
30 struct mutex _hurd_siglock;
33 /* Port that receives signals and other miscellaneous messages. */
34 mach_port_t _hurd_msgport;
36 /* Thread listening on it. */
37 thread_t _hurd_msgport_thread;
39 /* Thread which receives task-global signals. */
40 thread_t _hurd_sigthread;
42 /* Linked-list of per-thread signal state. */
43 struct hurd_sigstate *_hurd_sigstates;
45 /* Timeout for RPC's after interrupt_operation. */
46 mach_msg_timeout_t _hurd_interrupted_rpc_timeout = 3000;
49 default_sigaction (struct sigaction actions[NSIG])
53 __sigemptyset (&actions[0].sa_mask);
54 actions[0].sa_flags = SA_RESTART;
55 actions[0].sa_handler = SIG_DFL;
57 for (signo = 1; signo < NSIG; ++signo)
58 actions[signo] = actions[0];
61 struct hurd_sigstate *
62 _hurd_thread_sigstate (thread_t thread)
64 struct hurd_sigstate *ss;
65 __mutex_lock (&_hurd_siglock);
66 for (ss = _hurd_sigstates; ss != NULL; ss = ss->next)
67 if (ss->thread == thread)
71 ss = malloc (sizeof (*ss));
73 __libc_fatal ("hurd: Can't allocate thread sigstate\n");
75 __spin_lock_init (&ss->lock);
77 /* Initialize default state. */
78 __sigemptyset (&ss->blocked);
79 __sigemptyset (&ss->pending);
80 memset (&ss->sigaltstack, 0, sizeof (ss->sigaltstack));
81 ss->preempters = NULL;
83 ss->intr_port = MACH_PORT_NULL;
86 /* Initialize the sigaction vector from the default signal receiving
87 thread's state, and its from the system defaults. */
88 if (thread == _hurd_sigthread)
89 default_sigaction (ss->actions);
92 struct hurd_sigstate *s;
93 for (s = _hurd_sigstates; s != NULL; s = s->next)
94 if (s->thread == _hurd_sigthread)
98 __spin_lock (&s->lock);
99 memcpy (ss->actions, s->actions, sizeof (s->actions));
100 __spin_unlock (&s->lock);
103 default_sigaction (ss->actions);
106 ss->next = _hurd_sigstates;
107 _hurd_sigstates = ss;
109 __mutex_unlock (&_hurd_siglock);
113 /* Signal delivery itself is on this page. */
116 #include <hurd/crash.h>
117 #include <hurd/paths.h>
120 #include <sys/wait.h>
121 #include "thread_state.h"
122 #include <hurd/msg_server.h>
123 #include <hurd/msg_reply.h> /* For __msg_sig_post_reply. */
124 #include <hurd/interrupt.h>
128 int _hurd_core_limit; /* XXX */
130 /* Call the crash dump server to mummify us before we die.
131 Returns nonzero if a core file was written. */
133 write_corefile (int signo, const struct hurd_signal_detail *detail)
136 mach_port_t coreserver;
137 file_t file, coredir;
141 When we have a protocol to make the server return an error
142 for RLIMIT_FSIZE, then tell the corefile fs server the RLIMIT_CORE
143 value in place of the RLIMIT_FSIZE value. */
145 /* First get a port to the core dumping server. */
146 coreserver = MACH_PORT_NULL;
147 name = _hurdsig_getenv ("CRASHSERVER");
149 coreserver = __file_name_lookup (name, 0, 0);
150 if (coreserver == MACH_PORT_NULL)
151 coreserver = __file_name_lookup (_SERVERS_CRASH, 0, 0);
152 if (coreserver == MACH_PORT_NULL)
155 /* Get a port to the directory where the new core file will reside. */
156 name = _hurdsig_getenv ("COREFILE");
159 coredir = __file_name_split (name, (char **) &name);
160 if (coredir == MACH_PORT_NULL)
162 /* Create the new file, but don't link it into the directory yet. */
163 if (err = __dir_mkfile (coredir, O_WRONLY|O_CREAT,
164 0600 & ~_hurd_umask, /* XXX ? */
168 /* Call the core dumping server to write the core file. */
169 err = __crash_dump_task (coreserver,
172 signo, detail->code, detail->error,
173 detail->exc, detail->exc_code, detail->exc_subcode,
174 _hurd_ports[INIT_PORT_CTTYID].port,
175 MACH_MSG_TYPE_COPY_SEND);
176 __mach_port_deallocate (__mach_task_self (), coreserver);
178 /* The core dump into FILE succeeded, so now link it into the
180 err = __dir_link (file, coredir, name, 1);
181 __mach_port_deallocate (__mach_task_self (), file);
182 __mach_port_deallocate (__mach_task_self (), coredir);
187 /* The lowest-numbered thread state flavor value is 1,
188 so we use bit 0 in machine_thread_all_state.set to
189 record whether we have done thread_abort. */
190 #define THREAD_ABORTED 1
192 /* SS->thread is suspended. Abort the thread and get its basic state. */
194 abort_thread (struct hurd_sigstate *ss, struct machine_thread_all_state *state,
195 void (*reply) (void))
197 if (!(state->set & THREAD_ABORTED))
199 error_t err = __thread_abort (ss->thread);
201 /* Clear all thread state flavor set bits, because thread_abort may
202 have changed the state. */
203 state->set = THREAD_ABORTED;
209 machine_get_basic_state (ss->thread, state);
212 /* Find the location of the MiG reply port cell in use by the thread whose
213 state is described by THREAD_STATE. If SIGTHREAD is nonzero, make sure
214 that this location can be set without faulting, or else return NULL. */
217 interrupted_reply_port_location (struct machine_thread_all_state *thread_state,
220 mach_port_t *portloc = (mach_port_t *) __hurd_threadvar_location_from_sp
221 (_HURD_THREADVAR_MIG_REPLY, (void *) thread_state->basic.SP);
223 if (sigthread && _hurdsig_catch_memory_fault (portloc))
224 /* Faulted trying to read the stack. */
227 /* Fault now if this pointer is bogus. */
228 *(volatile mach_port_t *) portloc = *portloc;
231 _hurdsig_end_catch_fault ();
236 #include <hurd/sigpreempt.h>
237 #include "intr-msg.h"
239 /* Timeout on interrupt_operation calls. */
240 mach_msg_timeout_t _hurdsig_interrupt_timeout = 1000;
242 /* SS->thread is suspended.
244 Abort any interruptible RPC operation the thread is doing.
246 This uses only the constant member SS->thread and the unlocked, atomically
247 set member SS->intr_port, so no locking is needed.
249 If successfully sent an interrupt_operation and therefore the thread should
250 wait for its pending RPC to return (possibly EINTR) before taking the
251 incoming signal, returns the reply port to be received on. Otherwise
252 returns MACH_PORT_NULL.
254 SIGNO is used to find the applicable SA_RESTART bit. If SIGNO is zero,
255 the RPC fails with EINTR instead of restarting (thread_cancel).
257 *STATE_CHANGE is set nonzero if STATE->basic was modified and should
258 be applied back to the thread if it might ever run again, else zero. */
261 _hurdsig_abort_rpcs (struct hurd_sigstate *ss, int signo, int sigthread,
262 struct machine_thread_all_state *state, int *state_change,
263 void (*reply) (void))
265 extern const void _hurd_intr_rpc_msg_in_trap;
266 mach_port_t rcv_port = MACH_PORT_NULL;
267 mach_port_t intr_port;
271 intr_port = ss->intr_port;
272 if (intr_port == MACH_PORT_NULL)
273 /* No interruption needs done. */
274 return MACH_PORT_NULL;
276 /* Abort the thread's kernel context, so any pending message send or
277 receive completes immediately or aborts. */
278 abort_thread (ss, state, reply);
280 if (state->basic.PC < (natural_t) &_hurd_intr_rpc_msg_in_trap)
282 /* The thread is about to do the RPC, but hasn't yet entered
283 mach_msg. Mutate the thread's state so it knows not to try
285 INTR_MSG_BACK_OUT (&state->basic);
286 MACHINE_THREAD_STATE_SET_PC (&state->basic,
287 &_hurd_intr_rpc_msg_in_trap);
288 state->basic.SYSRETURN = MACH_SEND_INTERRUPTED;
291 else if (state->basic.PC == (natural_t) &_hurd_intr_rpc_msg_in_trap &&
292 /* The thread was blocked in the system call. After thread_abort,
293 the return value register indicates what state the RPC was in
295 state->basic.SYSRETURN == MACH_RCV_INTERRUPTED)
297 /* The RPC request message was sent and the thread was waiting for
298 the reply message; now the message receive has been aborted, so
299 the mach_msg call will return MACH_RCV_INTERRUPTED. We must tell
300 the server to interrupt the pending operation. The thread must
301 wait for the reply message before running the signal handler (to
302 guarantee that the operation has finished being interrupted), so
303 our nonzero return tells the trampoline code to finish the message
304 receive operation before running the handler. */
306 mach_port_t *reply = interrupted_reply_port_location (state,
308 error_t err = __interrupt_operation (intr_port, _hurdsig_interrupt_timeout);
314 /* The interrupt didn't work.
315 Destroy the receive right the thread is blocked on. */
316 __mach_port_destroy (__mach_task_self (), *reply);
317 *reply = MACH_PORT_NULL;
320 /* The system call return value register now contains
321 MACH_RCV_INTERRUPTED; when mach_msg resumes, it will retry the
322 call. Since we have just destroyed the receive right, the
323 retry will fail with MACH_RCV_INVALID_NAME. Instead, just
324 change the return value here to EINTR so mach_msg will not
325 retry and the EINTR error code will propagate up. */
326 state->basic.SYSRETURN = EINTR;
332 /* All threads whose RPCs were interrupted by the interrupt_operation
333 call above will retry their RPCs unless we clear SS->intr_port.
334 So we clear it for the thread taking a signal when SA_RESTART is
335 clear, so that its call returns EINTR. */
336 if (! signo || !(ss->actions[signo].sa_flags & SA_RESTART))
337 ss->intr_port = MACH_PORT_NULL;
344 /* Abort the RPCs being run by all threads but this one;
345 all other threads should be suspended. If LIVE is nonzero, those
346 threads may run again, so they should be adjusted as necessary to be
347 happy when resumed. STATE is clobbered as a scratch area; its initial
348 contents are ignored, and its contents on return are not useful. */
351 abort_all_rpcs (int signo, struct machine_thread_all_state *state, int live)
353 /* We can just loop over the sigstates. Any thread doing something
354 interruptible must have one. We needn't bother locking because all
355 other threads are stopped. */
357 struct hurd_sigstate *ss;
359 mach_port_t *reply_ports;
361 /* First loop over the sigstates to count them.
362 We need to know how big a vector we will need for REPLY_PORTS. */
364 for (ss = _hurd_sigstates; ss != NULL; ss = ss->next)
367 reply_ports = alloca (nthreads * sizeof *reply_ports);
370 for (ss = _hurd_sigstates; ss != NULL; ss = ss->next, ++nthreads)
371 if (ss->thread == _hurd_msgport_thread)
372 reply_ports[nthreads] = MACH_PORT_NULL;
376 state->set = 0; /* Reset scratch area. */
378 /* Abort any operation in progress with interrupt_operation.
379 Record the reply port the thread is waiting on.
380 We will wait for all the replies below. */
381 reply_ports[nthreads] = _hurdsig_abort_rpcs (ss, signo, 1,
382 state, &state_changed,
386 if (reply_ports[nthreads] != MACH_PORT_NULL)
388 /* We will wait for the reply to this RPC below, so the
389 thread must issue a new RPC rather than waiting for the
390 reply to the one it sent. */
391 state->basic.SYSRETURN = EINTR;
395 /* Aborting the RPC needed to change this thread's state,
396 and it might ever run again. So write back its state. */
397 __thread_set_state (ss->thread, MACHINE_THREAD_STATE_FLAVOR,
398 (natural_t *) &state->basic,
399 MACHINE_THREAD_STATE_COUNT);
403 /* Wait for replies from all the successfully interrupted RPCs. */
404 while (nthreads-- > 0)
405 if (reply_ports[nthreads] != MACH_PORT_NULL)
408 mach_msg_header_t head;
409 err = __mach_msg (&head, MACH_RCV_MSG|MACH_RCV_TIMEOUT, 0, sizeof head,
410 reply_ports[nthreads],
411 _hurd_interrupted_rpc_timeout, MACH_PORT_NULL);
414 case MACH_RCV_TIMED_OUT:
415 case MACH_RCV_TOO_LARGE:
424 struct hurd_signal_preempter *_hurdsig_preempters;
425 sigset_t _hurdsig_preempted_set;
427 /* Mask of stop signals. */
428 #define STOPSIGS (sigmask (SIGTTIN) | sigmask (SIGTTOU) | \
429 sigmask (SIGSTOP) | sigmask (SIGTSTP))
431 /* Deliver a signal. SS is not locked. */
433 _hurd_internal_post_signal (struct hurd_sigstate *ss,
434 int signo, struct hurd_signal_detail *detail,
435 mach_port_t reply_port,
436 mach_msg_type_name_t reply_port_type,
440 struct machine_thread_all_state thread_state;
441 enum { stop, ignore, core, term, handle } act;
442 struct hurd_signal_preempter *pe;
443 sighandler_t handler;
447 /* Reply to this sig_post message. */
448 __typeof (__msg_sig_post_reply) *reply_rpc
449 = (untraced ? __msg_sig_post_untraced_reply : __msg_sig_post_reply);
453 if (reply_port == MACH_PORT_NULL)
455 err = (*reply_rpc) (reply_port, reply_port_type, 0);
456 reply_port = MACH_PORT_NULL;
457 if (err != MACH_SEND_INVALID_DEST) /* Ignore dead reply port. */
461 /* Mark the signal as pending. */
462 void mark_pending (void)
464 __sigaddset (&ss->pending, signo);
465 /* Save the details to be given to the handler when SIGNO is
467 ss->pending_data[signo] = *detail;
470 /* Suspend the process with SIGNO. */
473 /* Stop all other threads and mark ourselves stopped. */
476 /* Hold the siglock while stopping other threads to be
477 sure it is not held by another thread afterwards. */
478 __mutex_lock (&_hurd_siglock);
479 __proc_dostop (port, _hurd_msgport_thread);
480 __mutex_unlock (&_hurd_siglock);
481 abort_all_rpcs (signo, &thread_state, 1);
483 __proc_mark_stop (port, signo, detail->code);
487 /* Resume the process after a suspension. */
490 /* Resume the process from being stopped. */
492 mach_msg_type_number_t nthreads, i;
498 /* Tell the proc server we are continuing. */
499 __USEPORT (PROC, __proc_mark_cont (port));
500 /* Fetch ports to all our threads and resume them. */
501 err = __task_threads (__mach_task_self (), &threads, &nthreads);
503 for (i = 0; i < nthreads; ++i)
505 if (threads[i] != _hurd_msgport_thread &&
506 (act != handle || threads[i] != ss->thread))
508 err = __thread_resume (threads[i]);
511 err = __mach_port_deallocate (__mach_task_self (),
515 __vm_deallocate (__mach_task_self (),
516 (vm_address_t) threads,
517 nthreads * sizeof *threads);
520 /* The thread that will run the handler is already suspended. */
527 /* This is PTRACE_CONTINUE. */
530 /* This call is just to check for pending signals. */
531 __spin_lock (&ss->lock);
532 goto check_pending_signals;
537 thread_state.set = 0; /* We know nothing. */
539 __spin_lock (&ss->lock);
541 /* Check for a preempted signal. Preempted signals can arrive during
542 critical sections. */
545 for (pe = ss->preempters; pe && handler == SIG_ERR; pe = pe->next)
546 if (HURD_PREEMPT_SIGNAL_P (pe, signo, detail->code))
547 handler = (*pe->preempter) (pe, ss, &signo, detail);
549 if (handler == SIG_ERR && (__sigmask (signo) & _hurdsig_preempted_set))
551 __mutex_lock (&_hurd_siglock);
552 for (pe = _hurdsig_preempters; pe && handler == SIG_ERR; pe = pe->next)
553 if (HURD_PREEMPT_SIGNAL_P (pe, signo, detail->code))
554 handler = (*pe->preempter) (pe, ss, &signo, detail);
555 __mutex_unlock (&_hurd_siglock);
560 if (handler == SIG_IGN)
561 /* Ignore the signal altogether. */
563 if (handler != SIG_ERR)
564 /* Run the preemption-provided handler. */
568 /* No preemption. Do normal handling. */
570 if (!untraced && __sigismember (&_hurdsig_traced, signo))
572 /* We are being traced. Stop to tell the debugger of the signal. */
574 /* Already stopped. Mark the signal as pending;
575 when resumed, we will notice it and stop again. */
579 __spin_unlock (&ss->lock);
584 handler = ss->actions[signo].sa_handler;
586 if (handler == SIG_DFL)
587 /* Figure out the default action for this signal. */
591 /* A sig_post msg with SIGNO==0 is sent to
592 tell us to check for pending signals. */
624 if (_hurd_pgrp == _hurd_pid)
626 /* We are the process group leader. Since there is no
627 user-specified handler for SIGINFO, we use a default one
628 which prints something interesting. We use the normal
629 handler mechanism instead of just doing it here to avoid
630 the signal thread faulting or blocking in this
631 potentially hairy operation. */
633 handler = _hurd_siginfo_handler;
643 else if (handler == SIG_IGN)
648 if (__sigmask (signo) & STOPSIGS)
649 /* Stop signals clear a pending SIGCONT even if they
650 are handled or ignored (but not if preempted). */
651 ss->pending &= ~sigmask (SIGCONT);
654 if (signo == SIGCONT)
655 /* Even if handled or ignored (but not preempted), SIGCONT clears
656 stop signals and resumes the process. */
657 ss->pending &= ~STOPSIGS;
659 if (_hurd_stopped && act != stop && (untraced || signo == SIGCONT))
664 if (_hurd_orphaned && act == stop &&
665 (__sigmask (signo) & (__sigmask (SIGTTIN) | __sigmask (SIGTTOU) |
666 __sigmask (SIGTSTP))))
668 /* If we would ordinarily stop for a job control signal, but we are
669 orphaned so noone would ever notice and continue us again, we just
670 quietly die, alone and in the dark. */
671 detail->code = signo;
676 /* Handle receipt of a blocked signal, or any signal while stopped. */
677 if (act != ignore && /* Signals ignored now are forgotten now. */
678 __sigismember (&ss->blocked, signo) ||
679 (signo != SIGKILL && _hurd_stopped))
685 /* Perform the chosen action for the signal. */
691 /* We are already stopped, but receiving an untraced stop
692 signal. Instead of resuming and suspending again, just
693 notify the proc server of the new stop signal. */
694 error_t err = __USEPORT (PROC, __proc_mark_stop
695 (port, signo, detail->code));
699 /* Suspend the process. */
704 /* Nobody cares about this signal. If there was a call to resume
705 above in SIGCONT processing and we've left a thread suspended,
706 now's the time to set it going. */
709 err = __thread_resume (ss->thread);
716 /* We got a fault setting up the stack frame for the handler.
717 Nothing to do but die; BSD gets SIGILL in this case. */
718 detail->code = signo; /* XXX ? */
723 case term: /* Time to die. */
724 case core: /* And leave a rotting corpse. */
725 /* Have the proc server stop all other threads in our task. */
726 err = __USEPORT (PROC, __proc_dostop (port, _hurd_msgport_thread));
728 /* No more user instructions will be executed.
729 The signal can now be considered delivered. */
731 /* Abort all server operations now in progress. */
732 abort_all_rpcs (signo, &thread_state, 0);
735 int status = W_EXITCODE (0, signo);
736 /* Do a core dump if desired. Only set the wait status bit saying we
737 in fact dumped core if the operation was actually successful. */
738 if (act == core && write_corefile (signo, detail))
740 /* Tell proc how we died and then stick the saber in the gut. */
746 /* Call a handler for this signal. */
748 struct sigcontext *scp, ocontext;
749 int wait_for_reply, state_changed;
751 /* Stop the thread and abort its pending RPC operations. */
754 err = __thread_suspend (ss->thread);
758 /* Abort the thread's kernel context, so any pending message send
759 or receive completes immediately or aborts. If an interruptible
760 RPC is in progress, abort_rpcs will do this. But we must always
761 do it before fetching the thread's state, because
762 thread_get_state is never kosher before thread_abort. */
763 abort_thread (ss, &thread_state, NULL);
767 /* We have a previous sigcontext that sigreturn was about
768 to restore when another signal arrived. */
772 if (_hurdsig_catch_memory_fault (ss->context))
774 /* We faulted reading the thread's stack. Forget that
775 context and pretend it wasn't there. It almost
776 certainly crash if this handler returns, but that's it's
782 /* Copy the context from the thread's stack before
783 we start diddling the stack to set up the handler. */
784 ocontext = *ss->context;
785 ss->context = &ocontext;
787 _hurdsig_end_catch_fault ();
789 if (! machine_get_basic_state (ss->thread, &thread_state))
791 loc = interrupted_reply_port_location (&thread_state, 1);
792 if (loc && *loc != MACH_PORT_NULL)
793 /* This is the reply port for the context which called
794 sigreturn. Since we are abandoning that context entirely
795 and restoring SS->context instead, destroy this port. */
796 __mach_port_destroy (__mach_task_self (), *loc);
798 /* The thread was in sigreturn, not in any interruptible RPC. */
801 assert (! __spin_lock_locked (&ss->critical_section_lock));
806 = (_hurdsig_abort_rpcs (ss, signo, 1,
807 &thread_state, &state_changed,
811 if (__spin_lock_locked (&ss->critical_section_lock))
813 /* The thread is in a critical section. Mark the signal as
814 pending. When it finishes the critical section, it will
815 check for pending signals. */
817 assert (! state_changed);
818 __thread_resume (ss->thread);
823 /* Call the machine-dependent function to set the thread up
824 to run the signal handler, and preserve its old context. */
825 scp = _hurd_setup_sighandler (ss, handler, signo, detail,
826 wait_for_reply, &thread_state);
830 /* Set the machine-independent parts of the signal context. */
833 /* Fetch the thread variable for the MiG reply port,
834 and set it to MACH_PORT_NULL. */
835 mach_port_t *loc = interrupted_reply_port_location (&thread_state,
839 scp->sc_reply_port = *loc;
840 *loc = MACH_PORT_NULL;
843 scp->sc_reply_port = MACH_PORT_NULL;
845 /* Save the intr_port in use by the interrupted code,
846 and clear the cell before running the trampoline. */
847 scp->sc_intr_port = ss->intr_port;
848 ss->intr_port = MACH_PORT_NULL;
852 /* After the handler runs we will restore to the state in
853 SS->context, not the state of the thread now. So restore
854 that context's reply port and intr port. */
856 scp->sc_reply_port = ss->context->sc_reply_port;
857 scp->sc_intr_port = ss->context->sc_intr_port;
863 /* Backdoor extra argument to signal handler. */
864 scp->sc_error = detail->error;
866 /* Block SIGNO and requested signals while running the handler. */
867 scp->sc_mask = ss->blocked;
868 ss->blocked |= __sigmask (signo) | ss->actions[signo].sa_mask;
870 /* Start the thread running the handler (or possibly waiting for an
871 RPC reply before running the handler). */
872 err = __thread_set_state (ss->thread, MACHINE_THREAD_STATE_FLAVOR,
873 (natural_t *) &thread_state.basic,
874 MACHINE_THREAD_STATE_COUNT);
876 err = __thread_resume (ss->thread);
878 thread_state.set = 0; /* Everything we know is now wrong. */
883 /* The signal has either been ignored or is now being handled. We can
884 consider it delivered and reply to the killer. */
887 /* We get here unless the signal was fatal. We still hold SS->lock.
888 Check for pending signals, and loop to post them. */
890 /* Return nonzero if SS has any signals pending we should worry about.
891 We don't worry about any pending signals if we are stopped, nor if
892 SS is in a critical section. We are guaranteed to get a sig_post
893 message before any of them become deliverable: either the SIGCONT
894 signal, or a sig_post with SIGNO==0 as an explicit poll when the
895 thread finishes its critical section. */
896 inline int signals_pending (void)
898 if (_hurd_stopped || __spin_lock_locked (&ss->critical_section_lock))
900 return pending = ss->pending & ~ss->blocked;
903 check_pending_signals:
906 if (signals_pending ())
908 for (signo = 1; signo < NSIG; ++signo)
909 if (__sigismember (&pending, signo))
912 __sigdelset (&ss->pending, signo);
913 *detail = ss->pending_data[signo];
914 __spin_unlock (&ss->lock);
919 /* No pending signals left undelivered for this thread.
920 If we were sent signal 0, we need to check for pending
921 signals for all threads. */
924 __spin_unlock (&ss->lock);
925 __mutex_lock (&_hurd_siglock);
926 for (ss = _hurd_sigstates; ss != NULL; ss = ss->next)
928 __spin_lock (&ss->lock);
929 for (signo = 1; signo < NSIG; ++signo)
930 if (__sigismember (&ss->pending, signo)
931 && (!__sigismember (&ss->blocked, signo)
932 /* We "deliver" immediately pending blocked signals whose
933 action might be to ignore, so that if ignored they are
934 dropped right away. */
935 || ss->actions[signo].sa_handler == SIG_IGN
936 || ss->actions[signo].sa_handler == SIG_DFL))
938 mutex_unlock (&_hurd_siglock);
939 goto deliver_pending;
941 __spin_unlock (&ss->lock);
943 __mutex_unlock (&_hurd_siglock);
947 /* No more signals pending; SS->lock is still locked.
948 Wake up any sigsuspend call that is blocking SS->thread. */
949 if (ss->suspended != MACH_PORT_NULL)
951 /* There is a sigsuspend waiting. Tell it to wake up. */
953 mach_msg_header_t msg;
954 err = __mach_port_insert_right (__mach_task_self (),
955 ss->suspended, ss->suspended,
956 MACH_MSG_TYPE_MAKE_SEND);
958 msg.msgh_bits = MACH_MSGH_BITS (MACH_MSG_TYPE_MOVE_SEND, 0);
959 msg.msgh_remote_port = ss->suspended;
960 msg.msgh_local_port = MACH_PORT_NULL;
961 /* These values do not matter. */
962 msg.msgh_id = 8675309; /* Jenny, Jenny. */
963 msg.msgh_seqno = 17; /* Random. */
964 ss->suspended = MACH_PORT_NULL;
965 err = __mach_msg (&msg, MACH_SEND_MSG, sizeof msg, 0,
966 MACH_PORT_NULL, MACH_MSG_TIMEOUT_NONE,
970 __spin_unlock (&ss->lock);
974 /* All pending signals delivered to all threads.
975 Now we can send the reply message even for signal 0. */
979 /* Decide whether REFPORT enables the sender to send us a SIGNO signal.
980 Returns zero if so, otherwise the error code to return to the sender. */
983 signal_allowed (int signo, mach_port_t refport)
985 if (signo < 0 || signo >= NSIG)
988 if (refport == __mach_task_self ())
989 /* Can send any signal. */
992 /* Avoid needing to check for this below. */
993 if (refport == MACH_PORT_NULL)
1005 /* Job control signals can be sent by the controlling terminal. */
1006 if (__USEPORT (CTTYID, port == refport))
1012 /* A continue signal can be sent by anyone in the session. */
1013 mach_port_t sessport;
1014 if (! __USEPORT (PROC, __proc_getsidport (port, &sessport)))
1016 __mach_port_deallocate (__mach_task_self (), sessport);
1017 if (refport == sessport)
1026 /* Any io object a file descriptor refers to might send us
1027 one of these signals using its async ID port for REFPORT.
1029 This is pretty wide open; it is not unlikely that some random
1030 process can at least open for reading something we have open,
1031 get its async ID port, and send us a spurious SIGIO or SIGURG
1032 signal. But BSD is actually wider open than that!--you can set
1033 the owner of an io object to any process or process group
1034 whatsoever and send them gratuitous signals.
1036 Someday we could implement some reasonable scheme for
1037 authorizing SIGIO and SIGURG signals properly. */
1040 int lucky = 0; /* True if we find a match for REFPORT. */
1041 __mutex_lock (&_hurd_dtable_lock);
1042 for (d = 0; !lucky && (unsigned) d < (unsigned) _hurd_dtablesize; ++d)
1044 struct hurd_userlink ulink;
1046 mach_port_t asyncid;
1047 if (_hurd_dtable[d] == NULL)
1049 port = _hurd_port_get (&_hurd_dtable[d]->port, &ulink);
1050 if (! __io_get_icky_async_id (port, &asyncid))
1052 if (refport == asyncid)
1053 /* Break out of the loop on the next iteration. */
1055 __mach_port_deallocate (__mach_task_self (), asyncid);
1057 _hurd_port_free (&_hurd_dtable[d]->port, &ulink, port);
1059 /* If we found a lucky winner, we've set D to -1 in the loop. */
1065 /* If this signal is legit, we have done `goto win' by now.
1066 When we return the error, mig deallocates REFPORT. */
1070 /* Deallocate the REFPORT send right; we are done with it. */
1071 __mach_port_deallocate (__mach_task_self (), refport);
1076 /* Implement the sig_post RPC from <hurd/msg.defs>;
1077 sent when someone wants us to get a signal. */
1079 _S_msg_sig_post (mach_port_t me,
1080 mach_port_t reply_port, mach_msg_type_name_t reply_port_type,
1081 int signo, natural_t sigcode,
1082 mach_port_t refport)
1085 struct hurd_signal_detail d;
1087 if (err = signal_allowed (signo, refport))
1093 /* Post the signal to the designated signal-receiving thread. This will
1094 reply when the signal can be considered delivered. */
1095 _hurd_internal_post_signal (_hurd_thread_sigstate (_hurd_sigthread),
1096 signo, &d, reply_port, reply_port_type,
1097 0); /* Stop if traced. */
1099 return MIG_NO_REPLY; /* Already replied. */
1102 /* Implement the sig_post_untraced RPC from <hurd/msg.defs>;
1103 sent when the debugger wants us to really get a signal
1104 even if we are traced. */
1106 _S_msg_sig_post_untraced (mach_port_t me,
1107 mach_port_t reply_port,
1108 mach_msg_type_name_t reply_port_type,
1109 int signo, natural_t sigcode,
1110 mach_port_t refport)
1113 struct hurd_signal_detail d;
1115 if (err = signal_allowed (signo, refport))
1121 /* Post the signal to the designated signal-receiving thread. This will
1122 reply when the signal can be considered delivered. */
1123 _hurd_internal_post_signal (_hurd_thread_sigstate (_hurd_sigthread),
1124 signo, &d, reply_port, reply_port_type,
1125 1); /* Untraced flag. */
1127 return MIG_NO_REPLY; /* Already replied. */
1130 extern void __mig_init (void *);
1132 #include <mach/task_special_ports.h>
1134 /* Initialize the message port and _hurd_sigthread and start the signal
1138 _hurdsig_init (void)
1141 vm_size_t stacksize;
1143 __mutex_init (&_hurd_siglock);
1145 err = __mach_port_allocate (__mach_task_self (),
1146 MACH_PORT_RIGHT_RECEIVE,
1148 assert_perror (err);
1150 /* Make a send right to the signal port. */
1151 err = __mach_port_insert_right (__mach_task_self (),
1154 MACH_MSG_TYPE_MAKE_SEND);
1155 assert_perror (err);
1157 /* Set the default thread to receive task-global signals
1158 to this one, the main (first) user thread. */
1159 _hurd_sigthread = __mach_thread_self ();
1161 /* Start the signal thread listening on the message port. */
1163 err = __thread_create (__mach_task_self (), &_hurd_msgport_thread);
1164 assert_perror (err);
1166 stacksize = __vm_page_size * 4; /* Small stack for signal thread. */
1167 err = __mach_setup_thread (__mach_task_self (), _hurd_msgport_thread,
1168 _hurd_msgport_receive,
1169 (vm_address_t *) &__hurd_sigthread_stack_base,
1171 assert_perror (err);
1173 __hurd_sigthread_stack_end = __hurd_sigthread_stack_base + stacksize;
1174 __hurd_sigthread_variables =
1175 malloc (__hurd_threadvar_max * sizeof (unsigned long int));
1176 if (__hurd_sigthread_variables == NULL)
1177 __libc_fatal ("hurd: Can't allocate thread variables for signal thread\n");
1179 /* Reinitialize the MiG support routines so they will use a per-thread
1180 variable for the cached reply port. */
1181 __mig_init ((void *) __hurd_sigthread_stack_base);
1183 err = __thread_resume (_hurd_msgport_thread);
1184 assert_perror (err);
1186 /* Receive exceptions on the signal port. */
1187 __task_set_special_port (__mach_task_self (),
1188 TASK_EXCEPTION_PORT, _hurd_msgport);
1191 /* Reauthenticate with the proc server. */
1194 reauth_proc (mach_port_t new)
1196 mach_port_t ref, ignore;
1198 ref = __mach_reply_port ();
1199 if (! HURD_PORT_USE (&_hurd_ports[INIT_PORT_PROC],
1200 __proc_reauthenticate (port, ref,
1201 MACH_MSG_TYPE_MAKE_SEND) ||
1202 __auth_user_authenticate (new, ref,
1203 MACH_MSG_TYPE_MAKE_SEND,
1205 && ignore != MACH_PORT_NULL)
1206 __mach_port_deallocate (__mach_task_self (), ignore);
1207 __mach_port_destroy (__mach_task_self (), ref);
1209 (void) &reauth_proc; /* Silence compiler warning. */
1211 text_set_element (_hurd_reauth_hook, reauth_proc);
1213 /* Like `getenv', but safe for the signal thread to run.
1214 If the environment is trashed, this will just return NULL. */
1217 _hurdsig_getenv (const char *variable)
1219 if (_hurdsig_catch_memory_fault (__environ))
1220 /* We bombed in getenv. */
1224 const size_t len = strlen (variable);
1226 char *volatile *ep = __environ;
1229 const char *p = *ep;
1230 _hurdsig_fault_preempter.first = (long int) p;
1231 _hurdsig_fault_preempter.last = VM_MAX_ADDRESS;
1232 if (! strncmp (p, variable, len) && p[len] == '=')
1237 valuelen = strlen (p);
1238 _hurdsig_fault_preempter.last = (long int) (p + valuelen);
1239 value = malloc (++valuelen);
1241 memcpy (value, p, valuelen);
1244 _hurdsig_fault_preempter.first = (long int) ++ep;
1245 _hurdsig_fault_preempter.last = (long int) (ep + 1);
1247 _hurdsig_end_catch_fault ();