2 * interrupt-handling magic
6 * This software is part of the SBCL system. See the README file for
9 * This software is derived from the CMU CL system, which was
10 * written at Carnegie Mellon University and released into the
11 * public domain. The software is in the public domain and is
12 * provided with absolutely no warranty. See the COPYING and CREDITS
13 * files for more information.
17 /* As far as I can tell, what's going on here is:
19 * In the case of most signals, when Lisp asks us to handle the
20 * signal, the outermost handler (the one actually passed to UNIX) is
21 * either interrupt_handle_now(..) or maybe_now_maybe_later(..).
22 * In that case, the Lisp-level handler is stored in interrupt_handlers[..]
23 * and interrupt_low_level_handlers[..] is cleared.
25 * However, some signals need special handling, e.g.
27 * o the SIGSEGV (for e.g. Linux) or SIGBUS (for e.g. FreeBSD) used by the
28 * garbage collector to detect violations of write protection,
29 * because some cases of such signals (e.g. GC-related violations of
30 * write protection) are handled at C level and never passed on to
31 * Lisp. For such signals, we still store any Lisp-level handler
32 * in interrupt_handlers[..], but for the outermost handle we use
33 * the value from interrupt_low_level_handlers[..], instead of the
34 * ordinary interrupt_handle_now(..) or interrupt_handle_later(..).
36 * o the SIGTRAP (Linux/Alpha) which Lisp code uses to handle breakpoints,
37 * pseudo-atomic sections, and some classes of error (e.g. "function
38 * not defined"). This never goes anywhere near the Lisp handlers at all.
39 * See runtime/alpha-arch.c and code/signal.lisp
41 * - WHN 20000728, dan 20010128 */
48 #include <sys/types.h>
55 #include "interrupt.h"
64 #include "genesis/fdefn.h"
65 #include "genesis/simple-fun.h"
69 void run_deferred_handler(struct interrupt_data *data, void *v_context) ;
70 static void store_signal_data_for_later (struct interrupt_data *data,
71 void *handler, int signal,
73 os_context_t *context);
74 boolean interrupt_maybe_gc_int(int signal, siginfo_t *info, void *v_context);
76 extern volatile lispobj all_threads_lock;
79 * This is a workaround for some slightly silly Linux/GNU Libc
80 * behaviour: glibc defines sigset_t to support 1024 signals, which is
81 * more than the kernel. This is usually not a problem, but becomes
82 * one when we want to save a signal mask from a ucontext, and restore
83 * it later into another ucontext: the ucontext is allocated on the
84 * stack by the kernel, so copying a libc-sized sigset_t into it will
85 * overflow and cause other data on the stack to be corrupted */
87 #define REAL_SIGSET_SIZE_BYTES ((NSIG/8))
89 void sigaddset_blockable(sigset_t *s)
93 sigaddset(s, SIGQUIT);
94 sigaddset(s, SIGPIPE);
95 sigaddset(s, SIGALRM);
98 sigaddset(s, SIGTSTP);
99 sigaddset(s, SIGCHLD);
101 sigaddset(s, SIGXCPU);
102 sigaddset(s, SIGXFSZ);
103 sigaddset(s, SIGVTALRM);
104 sigaddset(s, SIGPROF);
105 sigaddset(s, SIGWINCH);
106 sigaddset(s, SIGUSR1);
107 sigaddset(s, SIGUSR2);
108 #ifdef LISP_FEATURE_SB_THREAD
109 sigaddset(s, SIG_STOP_FOR_GC);
110 sigaddset(s, SIG_INTERRUPT_THREAD);
111 sigaddset(s, SIG_THREAD_EXIT);
115 /* When we catch an internal error, should we pass it back to Lisp to
116 * be handled in a high-level way? (Early in cold init, the answer is
117 * 'no', because Lisp is still too brain-dead to handle anything.
118 * After sufficient initialization has been completed, the answer
120 boolean internal_errors_enabled = 0;
122 struct interrupt_data * global_interrupt_data;
124 /* At the toplevel repl we routinely call this function. The signal
125 * mask ought to be clear anyway most of the time, but may be non-zero
126 * if we were interrupted e.g. while waiting for a queue. */
129 void reset_signal_mask ()
133 sigprocmask(SIG_SETMASK,&new,0);
136 void reset_signal_mask ()
142 sigprocmask(SIG_SETMASK,&new,&old);
143 for(i=1; i<NSIG; i++) {
144 if(sigismember(&old,i)) {
146 "Warning: signal %d is masked: this is unexpected\n",i);
151 fprintf(stderr,"If this version of SBCL is less than three months old, please report this.\nOtherwise, please try a newer version first\n. Reset signal mask.\n");
159 * utility routines used by various signal handlers
163 build_fake_control_stack_frames(struct thread *th,os_context_t *context)
165 #ifndef LISP_FEATURE_X86
169 /* Build a fake stack frame or frames */
171 current_control_frame_pointer =
172 (lispobj *)(*os_context_register_addr(context, reg_CSP));
173 if ((lispobj *)(*os_context_register_addr(context, reg_CFP))
174 == current_control_frame_pointer) {
175 /* There is a small window during call where the callee's
176 * frame isn't built yet. */
177 if (lowtag_of(*os_context_register_addr(context, reg_CODE))
178 == FUN_POINTER_LOWTAG) {
179 /* We have called, but not built the new frame, so
180 * build it for them. */
181 current_control_frame_pointer[0] =
182 *os_context_register_addr(context, reg_OCFP);
183 current_control_frame_pointer[1] =
184 *os_context_register_addr(context, reg_LRA);
185 current_control_frame_pointer += 8;
186 /* Build our frame on top of it. */
187 oldcont = (lispobj)(*os_context_register_addr(context, reg_CFP));
190 /* We haven't yet called, build our frame as if the
191 * partial frame wasn't there. */
192 oldcont = (lispobj)(*os_context_register_addr(context, reg_OCFP));
195 /* We can't tell whether we are still in the caller if it had to
196 * allocate a stack frame due to stack arguments. */
197 /* This observation provoked some past CMUCL maintainer to ask
198 * "Can anything strange happen during return?" */
201 oldcont = (lispobj)(*os_context_register_addr(context, reg_CFP));
204 current_control_stack_pointer = current_control_frame_pointer + 8;
206 current_control_frame_pointer[0] = oldcont;
207 current_control_frame_pointer[1] = NIL;
208 current_control_frame_pointer[2] =
209 (lispobj)(*os_context_register_addr(context, reg_CODE));
214 fake_foreign_function_call(os_context_t *context)
217 struct thread *thread=arch_os_get_current_thread();
219 /* Get current Lisp state from context. */
221 dynamic_space_free_pointer =
222 (lispobj *)(*os_context_register_addr(context, reg_ALLOC));
224 if ((long)dynamic_space_free_pointer & 1) {
225 lose("dead in fake_foreign_function_call, context = %x", context);
230 current_binding_stack_pointer =
231 (lispobj *)(*os_context_register_addr(context, reg_BSP));
234 build_fake_control_stack_frames(thread,context);
236 /* Do dynamic binding of the active interrupt context index
237 * and save the context in the context array. */
239 fixnum_value(SymbolValue(FREE_INTERRUPT_CONTEXT_INDEX,thread));
241 if (context_index >= MAX_INTERRUPTS) {
242 lose("maximum interrupt nesting depth (%d) exceeded", MAX_INTERRUPTS);
245 bind_variable(FREE_INTERRUPT_CONTEXT_INDEX,
246 make_fixnum(context_index + 1),thread);
248 thread->interrupt_contexts[context_index] = context;
250 /* no longer in Lisp now */
251 foreign_function_call_active = 1;
254 /* blocks all blockable signals. If you are calling from a signal handler,
255 * the usual signal mask will be restored from the context when the handler
256 * finishes. Otherwise, be careful */
259 undo_fake_foreign_function_call(os_context_t *context)
261 struct thread *thread=arch_os_get_current_thread();
262 /* Block all blockable signals. */
265 sigaddset_blockable(&block);
266 sigprocmask(SIG_BLOCK, &block, 0);
268 /* going back into Lisp */
269 foreign_function_call_active = 0;
271 /* Undo dynamic binding of FREE_INTERRUPT_CONTEXT_INDEX */
275 /* Put the dynamic space free pointer back into the context. */
276 *os_context_register_addr(context, reg_ALLOC) =
277 (unsigned long) dynamic_space_free_pointer;
281 /* a handler for the signal caused by execution of a trap opcode
282 * signalling an internal error */
284 interrupt_internal_error(int signal, siginfo_t *info, os_context_t *context,
287 lispobj context_sap = 0;
289 fake_foreign_function_call(context);
291 /* Allocate the SAP object while the interrupts are still
293 if (internal_errors_enabled) {
294 context_sap = alloc_sap(context);
297 sigprocmask(SIG_SETMASK, os_context_sigmask_addr(context), 0);
299 if (internal_errors_enabled) {
300 SHOW("in interrupt_internal_error");
302 /* Display some rudimentary debugging information about the
303 * error, so that even if the Lisp error handler gets badly
304 * confused, we have a chance to determine what's going on. */
305 describe_internal_error(context);
307 funcall2(SymbolFunction(INTERNAL_ERROR), context_sap,
308 continuable ? T : NIL);
310 describe_internal_error(context);
311 /* There's no good way to recover from an internal error
312 * before the Lisp error handling mechanism is set up. */
313 lose("internal error too early in init, can't recover");
315 undo_fake_foreign_function_call(context); /* blocks signals again */
317 arch_skip_instruction(context);
322 interrupt_handle_pending(os_context_t *context)
324 struct thread *thread;
325 struct interrupt_data *data;
327 thread=arch_os_get_current_thread();
328 data=thread->interrupt_data;
329 /* FIXME I'm not altogether sure this is appropriate if we're
330 * here as the result of a pseudo-atomic */
331 SetSymbolValue(INTERRUPT_PENDING, NIL,thread);
333 /* restore the saved signal mask from the original signal (the
334 * one that interrupted us during the critical section) into the
335 * os_context for the signal we're currently in the handler for.
336 * This should ensure that when we return from the handler the
337 * blocked signals are unblocked */
339 memcpy(os_context_sigmask_addr(context), &data->pending_mask,
340 REAL_SIGSET_SIZE_BYTES);
342 sigemptyset(&data->pending_mask);
343 /* This will break on sparc linux: the deferred handler really wants
344 * to be called with a void_context */
345 run_deferred_handler(data,(void *)context);
349 * the two main signal handlers:
350 * interrupt_handle_now(..)
351 * maybe_now_maybe_later(..)
353 * to which we have added interrupt_handle_now_handler(..). Why?
354 * Well, mostly because the SPARC/Linux platform doesn't quite do
355 * signals the way we want them done. The third argument in the
356 * handler isn't filled in by the kernel properly, so we fix it up
357 * ourselves in the arch_os_get_context(..) function; however, we only
358 * want to do this when we first hit the handler, and not when
359 * interrupt_handle_now(..) is being called from some other handler
360 * (when the fixup will already have been done). -- CSR, 2002-07-23
364 interrupt_handle_now(int signal, siginfo_t *info, void *void_context)
366 os_context_t *context = (os_context_t*)void_context;
367 struct thread *thread=arch_os_get_current_thread();
368 #ifndef LISP_FEATURE_X86
369 boolean were_in_lisp;
371 union interrupt_handler handler;
373 #ifdef LISP_FEATURE_LINUX
374 /* Under Linux on some architectures, we appear to have to restore
375 the FPU control word from the context, as after the signal is
376 delivered we appear to have a null FPU control word. */
377 os_restore_fp_control(context);
379 handler = thread->interrupt_data->interrupt_handlers[signal];
381 if (ARE_SAME_HANDLER(handler.c, SIG_IGN)) {
385 #ifndef LISP_FEATURE_X86
386 were_in_lisp = !foreign_function_call_active;
390 fake_foreign_function_call(context);
395 "/entering interrupt_handle_now(%d, info, context)\n",
399 if (ARE_SAME_HANDLER(handler.c, SIG_DFL)) {
401 /* This can happen if someone tries to ignore or default one
402 * of the signals we need for runtime support, and the runtime
403 * support decides to pass on it. */
404 lose("no handler for signal %d in interrupt_handle_now(..)", signal);
406 } else if (lowtag_of(handler.lisp) == FUN_POINTER_LOWTAG) {
407 /* Once we've decided what to do about contexts in a
408 * return-elsewhere world (the original context will no longer
409 * be available; should we copy it or was nobody using it anyway?)
410 * then we should convert this to return-elsewhere */
412 /* CMUCL comment said "Allocate the SAPs while the interrupts
413 * are still disabled.". I (dan, 2003.08.21) assume this is
414 * because we're not in pseudoatomic and allocation shouldn't
415 * be interrupted. In which case it's no longer an issue as
416 * all our allocation from C now goes through a PA wrapper,
417 * but still, doesn't hurt */
419 lispobj info_sap,context_sap = alloc_sap(context);
420 info_sap = alloc_sap(info);
421 /* Allow signals again. */
422 sigprocmask(SIG_SETMASK, os_context_sigmask_addr(context), 0);
425 SHOW("calling Lisp-level handler");
428 funcall3(handler.lisp,
435 SHOW("calling C-level handler");
438 /* Allow signals again. */
439 sigprocmask(SIG_SETMASK, os_context_sigmask_addr(context), 0);
441 (*handler.c)(signal, info, void_context);
444 #ifndef LISP_FEATURE_X86
448 undo_fake_foreign_function_call(context); /* block signals again */
453 "/returning from interrupt_handle_now(%d, info, context)\n",
458 /* This is called at the end of a critical section if the indications
459 * are that some signal was deferred during the section. Note that as
460 * far as C or the kernel is concerned we dealt with the signal
461 * already; we're just doing the Lisp-level processing now that we
465 run_deferred_handler(struct interrupt_data *data, void *v_context) {
466 (*(data->pending_handler))
467 (data->pending_signal,&(data->pending_info), v_context);
468 data->pending_handler=0;
472 maybe_defer_handler(void *handler, struct interrupt_data *data,
473 int signal, siginfo_t *info, os_context_t *context)
475 struct thread *thread=arch_os_get_current_thread();
476 if (SymbolValue(INTERRUPTS_ENABLED,thread) == NIL) {
477 store_signal_data_for_later(data,handler,signal,info,context);
478 SetSymbolValue(INTERRUPT_PENDING, T,thread);
481 /* a slightly confusing test. arch_pseudo_atomic_atomic() doesn't
482 * actually use its argument for anything on x86, so this branch
483 * may succeed even when context is null (gencgc alloc()) */
485 #ifndef LISP_FEATURE_X86
486 (!foreign_function_call_active) &&
488 arch_pseudo_atomic_atomic(context)) {
489 store_signal_data_for_later(data,handler,signal,info,context);
490 arch_set_pseudo_atomic_interrupted(context);
496 store_signal_data_for_later (struct interrupt_data *data, void *handler,
498 siginfo_t *info, os_context_t *context)
500 data->pending_handler = handler;
501 data->pending_signal = signal;
503 memcpy(&(data->pending_info), info, sizeof(siginfo_t));
505 /* the signal mask in the context (from before we were
506 * interrupted) is copied to be restored when
507 * run_deferred_handler happens. Then the usually-blocked
508 * signals are added to the mask in the context so that we are
509 * running with blocked signals when the handler returns */
510 sigemptyset(&(data->pending_mask));
511 memcpy(&(data->pending_mask),
512 os_context_sigmask_addr(context),
513 REAL_SIGSET_SIZE_BYTES);
514 sigaddset_blockable(os_context_sigmask_addr(context));
516 /* this is also called from gencgc alloc(), in which case
517 * there has been no signal and is therefore no context. */
520 sigaddset_blockable(&new);
521 sigprocmask(SIG_BLOCK,&new,&(data->pending_mask));
527 maybe_now_maybe_later(int signal, siginfo_t *info, void *void_context)
529 os_context_t *context = arch_os_get_context(&void_context);
530 struct thread *thread=arch_os_get_current_thread();
531 struct interrupt_data *data=thread->interrupt_data;
532 #ifdef LISP_FEATURE_LINUX
533 os_restore_fp_control(context);
535 if(maybe_defer_handler(interrupt_handle_now,data,
536 signal,info,context))
538 interrupt_handle_now(signal, info, context);
539 #ifdef LISP_FEATURE_DARWIN
540 /* Work around G5 bug */
541 sigreturn(void_context);
545 #ifdef LISP_FEATURE_SB_THREAD
547 sig_stop_for_gc_handler(int signal, siginfo_t *info, void *void_context)
549 os_context_t *context = arch_os_get_context(&void_context);
550 struct thread *thread=arch_os_get_current_thread();
551 struct interrupt_data *data=thread->interrupt_data;
555 if(maybe_defer_handler(sig_stop_for_gc_handler,data,
556 signal,info,context)) {
559 /* need the context stored so it can have registers scavenged */
560 fake_foreign_function_call(context);
563 for(i=1;i<NSIG;i++) sigaddset(&ss,i); /* Block everything. */
564 sigprocmask(SIG_BLOCK,&ss,0);
566 get_spinlock(&all_threads_lock,thread->pid);
567 thread->state=STATE_STOPPED;
568 release_spinlock(&all_threads_lock);
570 sigemptyset(&ss); sigaddset(&ss,SIG_STOP_FOR_GC);
573 undo_fake_foreign_function_call(context);
578 interrupt_handle_now_handler(int signal, siginfo_t *info, void *void_context)
580 os_context_t *context = arch_os_get_context(&void_context);
581 interrupt_handle_now(signal, info, context);
582 #ifdef LISP_FEATURE_DARWIN
583 sigreturn(void_context);
588 * stuff to detect and handle hitting the GC trigger
591 #ifndef LISP_FEATURE_GENCGC
592 /* since GENCGC has its own way to record trigger */
594 gc_trigger_hit(int signal, siginfo_t *info, os_context_t *context)
596 if (current_auto_gc_trigger == NULL)
599 void *badaddr=arch_get_bad_addr(signal,info,context);
600 return (badaddr >= (void *)current_auto_gc_trigger &&
601 badaddr <((void *)current_dynamic_space + DYNAMIC_SPACE_SIZE));
606 /* manipulate the signal context and stack such that when the handler
607 * returns, it will call function instead of whatever it was doing
611 extern lispobj call_into_lisp(lispobj fun, lispobj *args, int nargs);
612 extern void post_signal_tramp(void);
613 void arrange_return_to_lisp_function(os_context_t *context, lispobj function)
615 #ifndef LISP_FEATURE_X86
616 void * fun=native_pointer(function);
617 void *code = &(((struct simple_fun *) fun)->code);
620 /* Build a stack frame showing `interrupted' so that the
621 * user's backtrace makes (as much) sense (as usual) */
622 #ifdef LISP_FEATURE_X86
623 /* Suppose the existence of some function that saved all
624 * registers, called call_into_lisp, then restored GP registers and
625 * returned. We shortcut this: fake the stack that call_into_lisp
626 * would see, then arrange to have it called directly. post_signal_tramp
627 * is the second half of this function
629 u32 *sp=(u32 *)*os_context_register_addr(context,reg_ESP);
631 *(sp-14) = post_signal_tramp; /* return address for call_into_lisp */
632 *(sp-13) = function; /* args for call_into_lisp : function*/
633 *(sp-12) = 0; /* arg array */
634 *(sp-11) = 0; /* no. args */
635 /* this order matches that used in POPAD */
636 *(sp-10)=*os_context_register_addr(context,reg_EDI);
637 *(sp-9)=*os_context_register_addr(context,reg_ESI);
638 /* this gets overwritten again before it's used, anyway */
639 *(sp-8)=*os_context_register_addr(context,reg_EBP);
640 *(sp-7)=0 ; /* POPAD doesn't set ESP, but expects a gap for it anyway */
641 *(sp-6)=*os_context_register_addr(context,reg_EBX);
643 *(sp-5)=*os_context_register_addr(context,reg_EDX);
644 *(sp-4)=*os_context_register_addr(context,reg_ECX);
645 *(sp-3)=*os_context_register_addr(context,reg_EAX);
646 *(sp-2)=*os_context_register_addr(context,reg_EBP);
647 *(sp-1)=*os_context_pc_addr(context);
650 struct thread *th=arch_os_get_current_thread();
651 build_fake_control_stack_frames(th,context);
654 #ifdef LISP_FEATURE_X86
655 *os_context_pc_addr(context) = call_into_lisp;
656 *os_context_register_addr(context,reg_ECX) = 0;
657 *os_context_register_addr(context,reg_EBP) = sp-2;
658 *os_context_register_addr(context,reg_ESP) = sp-14;
660 /* this much of the calling convention is common to all
662 *os_context_pc_addr(context) = code;
663 *os_context_register_addr(context,reg_NARGS) = 0;
664 *os_context_register_addr(context,reg_LIP) = code;
665 *os_context_register_addr(context,reg_CFP) =
666 current_control_frame_pointer;
668 #ifdef ARCH_HAS_NPC_REGISTER
669 *os_context_npc_addr(context) =
670 4 + *os_context_pc_addr(context);
672 #ifdef LISP_FEATURE_SPARC
673 *os_context_register_addr(context,reg_CODE) =
674 fun + FUN_POINTER_LOWTAG;
678 #ifdef LISP_FEATURE_SB_THREAD
679 void interrupt_thread_handler(int num, siginfo_t *info, void *v_context)
681 os_context_t *context = (os_context_t*)arch_os_get_context(&v_context);
682 struct thread *th=arch_os_get_current_thread();
683 struct interrupt_data *data=
684 th ? th->interrupt_data : global_interrupt_data;
685 if(maybe_defer_handler(interrupt_thread_handler,data,num,info,context)){
688 arrange_return_to_lisp_function(context,info->si_value.sival_int);
691 void thread_exit_handler(int num, siginfo_t *info, void *v_context)
692 { /* called when a child thread exits */
693 os_context_t *context = (os_context_t*)arch_os_get_context(&v_context);
694 struct thread *th=arch_os_get_current_thread();
697 struct interrupt_data *data=
698 th ? th->interrupt_data : global_interrupt_data;
699 if(maybe_defer_handler(thread_exit_handler,data,num,info,context)){
703 kid=waitpid(-1,&status,__WALL|WNOHANG);
705 if(WIFEXITED(status) || WIFSIGNALED(status)) {
706 struct thread *th=find_thread_by_pid(kid);
708 funcall1(SymbolFunction(HANDLE_THREAD_EXIT),make_fixnum(kid));
715 boolean handle_control_stack_guard_triggered(os_context_t *context,void *addr){
716 struct thread *th=arch_os_get_current_thread();
717 /* note the os_context hackery here. When the signal handler returns,
718 * it won't go back to what it was doing ... */
719 if(addr>=(void *)CONTROL_STACK_GUARD_PAGE(th) &&
720 addr<(void *)(CONTROL_STACK_GUARD_PAGE(th)+os_vm_page_size)) {
721 /* we hit the end of the control stack. disable protection
722 * temporarily so the error handler has some headroom */
723 protect_control_stack_guard_page(th->pid,0L);
725 arrange_return_to_lisp_function
726 (context, SymbolFunction(CONTROL_STACK_EXHAUSTED_ERROR));
732 #ifndef LISP_FEATURE_GENCGC
733 /* This function gets called from the SIGSEGV (for e.g. Linux, NetBSD, &
734 * OpenBSD) or SIGBUS (for e.g. FreeBSD) handler. Here we check
735 * whether the signal was due to treading on the mprotect()ed zone -
736 * and if so, arrange for a GC to happen. */
737 extern unsigned long bytes_consed_between_gcs; /* gc-common.c */
740 interrupt_maybe_gc(int signal, siginfo_t *info, void *void_context)
742 os_context_t *context=(os_context_t *) void_context;
743 struct thread *th=arch_os_get_current_thread();
744 struct interrupt_data *data=
745 th ? th->interrupt_data : global_interrupt_data;
747 if(!foreign_function_call_active && gc_trigger_hit(signal, info, context)){
748 clear_auto_gc_trigger();
749 if(!maybe_defer_handler
750 (interrupt_maybe_gc_int,data,signal,info,void_context))
751 interrupt_maybe_gc_int(signal,info,void_context);
759 /* this is also used by gencgc, in alloc() */
761 interrupt_maybe_gc_int(int signal, siginfo_t *info, void *void_context)
764 os_context_t *context=(os_context_t *) void_context;
765 fake_foreign_function_call(context);
766 /* SUB-GC may return without GCing if *GC-INHIBIT* is set, in
767 * which case we will be running with no gc trigger barrier
768 * thing for a while. But it shouldn't be long until the end
769 * of WITHOUT-GCING. */
772 sigaddset_blockable(&new);
773 /* enable signals before calling into Lisp */
774 sigprocmask(SIG_UNBLOCK,&new,0);
775 funcall0(SymbolFunction(SUB_GC));
776 undo_fake_foreign_function_call(context);
782 * noise to install handlers
786 undoably_install_low_level_interrupt_handler (int signal,
792 struct thread *th=arch_os_get_current_thread();
793 struct interrupt_data *data=
794 th ? th->interrupt_data : global_interrupt_data;
796 if (0 > signal || signal >= NSIG) {
797 lose("bad signal number %d", signal);
800 sa.sa_sigaction = handler;
801 sigemptyset(&sa.sa_mask);
802 sigaddset_blockable(&sa.sa_mask);
803 sa.sa_flags = SA_SIGINFO | SA_RESTART;
804 #ifdef LISP_FEATURE_C_STACK_IS_CONTROL_STACK
805 if((signal==SIG_MEMORY_FAULT)
806 #ifdef SIG_INTERRUPT_THREAD
807 || (signal==SIG_INTERRUPT_THREAD)
810 sa.sa_flags|= SA_ONSTACK;
813 sigaction(signal, &sa, NULL);
814 data->interrupt_low_level_handlers[signal] =
815 (ARE_SAME_HANDLER(handler, SIG_DFL) ? 0 : handler);
818 /* This is called from Lisp. */
820 install_handler(int signal, void handler(int, siginfo_t*, void*))
824 union interrupt_handler oldhandler;
825 struct thread *th=arch_os_get_current_thread();
826 struct interrupt_data *data=
827 th ? th->interrupt_data : global_interrupt_data;
829 FSHOW((stderr, "/entering POSIX install_handler(%d, ..)\n", signal));
832 sigaddset(&new, signal);
833 sigprocmask(SIG_BLOCK, &new, &old);
836 sigaddset_blockable(&new);
838 FSHOW((stderr, "/data->interrupt_low_level_handlers[signal]=%d\n",
839 data->interrupt_low_level_handlers[signal]));
840 if (data->interrupt_low_level_handlers[signal]==0) {
841 if (ARE_SAME_HANDLER(handler, SIG_DFL) ||
842 ARE_SAME_HANDLER(handler, SIG_IGN)) {
843 sa.sa_sigaction = handler;
844 } else if (sigismember(&new, signal)) {
845 sa.sa_sigaction = maybe_now_maybe_later;
847 sa.sa_sigaction = interrupt_handle_now_handler;
850 sigemptyset(&sa.sa_mask);
851 sigaddset_blockable(&sa.sa_mask);
852 sa.sa_flags = SA_SIGINFO | SA_RESTART;
853 sigaction(signal, &sa, NULL);
856 oldhandler = data->interrupt_handlers[signal];
857 data->interrupt_handlers[signal].c = handler;
859 sigprocmask(SIG_SETMASK, &old, 0);
861 FSHOW((stderr, "/leaving POSIX install_handler(%d, ..)\n", signal));
863 return (unsigned long)oldhandler.lisp;
870 SHOW("entering interrupt_init()");
871 global_interrupt_data=calloc(sizeof(struct interrupt_data), 1);
873 /* Set up high level handler information. */
874 for (i = 0; i < NSIG; i++) {
875 global_interrupt_data->interrupt_handlers[i].c =
876 /* (The cast here blasts away the distinction between
877 * SA_SIGACTION-style three-argument handlers and
878 * signal(..)-style one-argument handlers, which is OK
879 * because it works to call the 1-argument form where the
880 * 3-argument form is expected.) */
881 (void (*)(int, siginfo_t*, void*))SIG_DFL;
884 SHOW("returning from interrupt_init()");