Merge tag 'pull-request-2022-09-28' of https://gitlab.com/thuth/qemu into staging
[qemu.git] / bsd-user / signal.c
1 /*
2 * Emulation of BSD signals
3 *
4 * Copyright (c) 2003 - 2008 Fabrice Bellard
5 * Copyright (c) 2013 Stacey Son
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, see <http://www.gnu.org/licenses/>.
19 */
20
21 #include "qemu/osdep.h"
22 #include "qemu/log.h"
23 #include "qemu.h"
24 #include "signal-common.h"
25 #include "trace.h"
26 #include "hw/core/tcg-cpu-ops.h"
27 #include "host-signal.h"
28
29 static struct target_sigaction sigact_table[TARGET_NSIG];
30 static void host_signal_handler(int host_sig, siginfo_t *info, void *puc);
31 static void target_to_host_sigset_internal(sigset_t *d,
32 const target_sigset_t *s);
33
34 static inline int on_sig_stack(TaskState *ts, unsigned long sp)
35 {
36 return sp - ts->sigaltstack_used.ss_sp < ts->sigaltstack_used.ss_size;
37 }
38
39 static inline int sas_ss_flags(TaskState *ts, unsigned long sp)
40 {
41 return ts->sigaltstack_used.ss_size == 0 ? SS_DISABLE :
42 on_sig_stack(ts, sp) ? SS_ONSTACK : 0;
43 }
44
45 /*
46 * The BSD ABIs use the same singal numbers across all the CPU architectures, so
47 * (unlike Linux) these functions are just the identity mapping. This might not
48 * be true for XyzBSD running on AbcBSD, which doesn't currently work.
49 */
50 int host_to_target_signal(int sig)
51 {
52 return sig;
53 }
54
55 int target_to_host_signal(int sig)
56 {
57 return sig;
58 }
59
60 static inline void target_sigemptyset(target_sigset_t *set)
61 {
62 memset(set, 0, sizeof(*set));
63 }
64
65 static inline void target_sigaddset(target_sigset_t *set, int signum)
66 {
67 signum--;
68 uint32_t mask = (uint32_t)1 << (signum % TARGET_NSIG_BPW);
69 set->__bits[signum / TARGET_NSIG_BPW] |= mask;
70 }
71
72 static inline int target_sigismember(const target_sigset_t *set, int signum)
73 {
74 signum--;
75 abi_ulong mask = (abi_ulong)1 << (signum % TARGET_NSIG_BPW);
76 return (set->__bits[signum / TARGET_NSIG_BPW] & mask) != 0;
77 }
78
79 /* Adjust the signal context to rewind out of safe-syscall if we're in it */
80 static inline void rewind_if_in_safe_syscall(void *puc)
81 {
82 ucontext_t *uc = (ucontext_t *)puc;
83 uintptr_t pcreg = host_signal_pc(uc);
84
85 if (pcreg > (uintptr_t)safe_syscall_start
86 && pcreg < (uintptr_t)safe_syscall_end) {
87 host_signal_set_pc(uc, (uintptr_t)safe_syscall_start);
88 }
89 }
90
91 /*
92 * Note: The following take advantage of the BSD signal property that all
93 * signals are available on all architectures.
94 */
95 static void host_to_target_sigset_internal(target_sigset_t *d,
96 const sigset_t *s)
97 {
98 int i;
99
100 target_sigemptyset(d);
101 for (i = 1; i <= NSIG; i++) {
102 if (sigismember(s, i)) {
103 target_sigaddset(d, host_to_target_signal(i));
104 }
105 }
106 }
107
108 void host_to_target_sigset(target_sigset_t *d, const sigset_t *s)
109 {
110 target_sigset_t d1;
111 int i;
112
113 host_to_target_sigset_internal(&d1, s);
114 for (i = 0; i < _SIG_WORDS; i++) {
115 d->__bits[i] = tswap32(d1.__bits[i]);
116 }
117 }
118
119 static void target_to_host_sigset_internal(sigset_t *d,
120 const target_sigset_t *s)
121 {
122 int i;
123
124 sigemptyset(d);
125 for (i = 1; i <= TARGET_NSIG; i++) {
126 if (target_sigismember(s, i)) {
127 sigaddset(d, target_to_host_signal(i));
128 }
129 }
130 }
131
132 void target_to_host_sigset(sigset_t *d, const target_sigset_t *s)
133 {
134 target_sigset_t s1;
135 int i;
136
137 for (i = 0; i < TARGET_NSIG_WORDS; i++) {
138 s1.__bits[i] = tswap32(s->__bits[i]);
139 }
140 target_to_host_sigset_internal(d, &s1);
141 }
142
143 static bool has_trapno(int tsig)
144 {
145 return tsig == TARGET_SIGILL ||
146 tsig == TARGET_SIGFPE ||
147 tsig == TARGET_SIGSEGV ||
148 tsig == TARGET_SIGBUS ||
149 tsig == TARGET_SIGTRAP;
150 }
151
152 /* Siginfo conversion. */
153
154 /*
155 * Populate tinfo w/o swapping based on guessing which fields are valid.
156 */
157 static inline void host_to_target_siginfo_noswap(target_siginfo_t *tinfo,
158 const siginfo_t *info)
159 {
160 int sig = host_to_target_signal(info->si_signo);
161 int si_code = info->si_code;
162 int si_type;
163
164 /*
165 * Make sure we that the variable portion of the target siginfo is zeroed
166 * out so we don't leak anything into that.
167 */
168 memset(&tinfo->_reason, 0, sizeof(tinfo->_reason));
169
170 /*
171 * This is awkward, because we have to use a combination of the si_code and
172 * si_signo to figure out which of the union's members are valid.o We
173 * therefore make our best guess.
174 *
175 * Once we have made our guess, we record it in the top 16 bits of
176 * the si_code, so that tswap_siginfo() later can use it.
177 * tswap_siginfo() will strip these top bits out before writing
178 * si_code to the guest (sign-extending the lower bits).
179 */
180 tinfo->si_signo = sig;
181 tinfo->si_errno = info->si_errno;
182 tinfo->si_code = info->si_code;
183 tinfo->si_pid = info->si_pid;
184 tinfo->si_uid = info->si_uid;
185 tinfo->si_status = info->si_status;
186 tinfo->si_addr = (abi_ulong)(unsigned long)info->si_addr;
187 /*
188 * si_value is opaque to kernel. On all FreeBSD platforms,
189 * sizeof(sival_ptr) >= sizeof(sival_int) so the following
190 * always will copy the larger element.
191 */
192 tinfo->si_value.sival_ptr =
193 (abi_ulong)(unsigned long)info->si_value.sival_ptr;
194
195 switch (si_code) {
196 /*
197 * All the SI_xxx codes that are defined here are global to
198 * all the signals (they have values that none of the other,
199 * more specific signal info will set).
200 */
201 case SI_USER:
202 case SI_LWP:
203 case SI_KERNEL:
204 case SI_QUEUE:
205 case SI_ASYNCIO:
206 /*
207 * Only the fixed parts are valid (though FreeBSD doesn't always
208 * set all the fields to non-zero values.
209 */
210 si_type = QEMU_SI_NOINFO;
211 break;
212 case SI_TIMER:
213 tinfo->_reason._timer._timerid = info->_reason._timer._timerid;
214 tinfo->_reason._timer._overrun = info->_reason._timer._overrun;
215 si_type = QEMU_SI_TIMER;
216 break;
217 case SI_MESGQ:
218 tinfo->_reason._mesgq._mqd = info->_reason._mesgq._mqd;
219 si_type = QEMU_SI_MESGQ;
220 break;
221 default:
222 /*
223 * We have to go based on the signal number now to figure out
224 * what's valid.
225 */
226 si_type = QEMU_SI_NOINFO;
227 if (has_trapno(sig)) {
228 tinfo->_reason._fault._trapno = info->_reason._fault._trapno;
229 si_type = QEMU_SI_FAULT;
230 }
231 #ifdef TARGET_SIGPOLL
232 /*
233 * FreeBSD never had SIGPOLL, but emulates it for Linux so there's
234 * a chance it may popup in the future.
235 */
236 if (sig == TARGET_SIGPOLL) {
237 tinfo->_reason._poll._band = info->_reason._poll._band;
238 si_type = QEMU_SI_POLL;
239 }
240 #endif
241 /*
242 * Unsure that this can actually be generated, and our support for
243 * capsicum is somewhere between weak and non-existant, but if we get
244 * one, then we know what to save.
245 */
246 #ifdef QEMU_SI_CAPSICUM
247 if (sig == TARGET_SIGTRAP) {
248 tinfo->_reason._capsicum._syscall =
249 info->_reason._capsicum._syscall;
250 si_type = QEMU_SI_CAPSICUM;
251 }
252 #endif
253 break;
254 }
255 tinfo->si_code = deposit32(si_code, 24, 8, si_type);
256 }
257
258 static void tswap_siginfo(target_siginfo_t *tinfo, const target_siginfo_t *info)
259 {
260 int si_type = extract32(info->si_code, 24, 8);
261 int si_code = sextract32(info->si_code, 0, 24);
262
263 __put_user(info->si_signo, &tinfo->si_signo);
264 __put_user(info->si_errno, &tinfo->si_errno);
265 __put_user(si_code, &tinfo->si_code); /* Zero out si_type, it's internal */
266 __put_user(info->si_pid, &tinfo->si_pid);
267 __put_user(info->si_uid, &tinfo->si_uid);
268 __put_user(info->si_status, &tinfo->si_status);
269 __put_user(info->si_addr, &tinfo->si_addr);
270 /*
271 * Unswapped, because we passed it through mostly untouched. si_value is
272 * opaque to the kernel, so we didn't bother with potentially wasting cycles
273 * to swap it into host byte order.
274 */
275 tinfo->si_value.sival_ptr = info->si_value.sival_ptr;
276
277 /*
278 * We can use our internal marker of which fields in the structure
279 * are valid, rather than duplicating the guesswork of
280 * host_to_target_siginfo_noswap() here.
281 */
282 switch (si_type) {
283 case QEMU_SI_NOINFO: /* No additional info */
284 break;
285 case QEMU_SI_FAULT:
286 __put_user(info->_reason._fault._trapno,
287 &tinfo->_reason._fault._trapno);
288 break;
289 case QEMU_SI_TIMER:
290 __put_user(info->_reason._timer._timerid,
291 &tinfo->_reason._timer._timerid);
292 __put_user(info->_reason._timer._overrun,
293 &tinfo->_reason._timer._overrun);
294 break;
295 case QEMU_SI_MESGQ:
296 __put_user(info->_reason._mesgq._mqd, &tinfo->_reason._mesgq._mqd);
297 break;
298 case QEMU_SI_POLL:
299 /* Note: Not generated on FreeBSD */
300 __put_user(info->_reason._poll._band, &tinfo->_reason._poll._band);
301 break;
302 #ifdef QEMU_SI_CAPSICUM
303 case QEMU_SI_CAPSICUM:
304 __put_user(info->_reason._capsicum._syscall,
305 &tinfo->_reason._capsicum._syscall);
306 break;
307 #endif
308 default:
309 g_assert_not_reached();
310 }
311 }
312
313 int block_signals(void)
314 {
315 TaskState *ts = (TaskState *)thread_cpu->opaque;
316 sigset_t set;
317
318 /*
319 * It's OK to block everything including SIGSEGV, because we won't run any
320 * further guest code before unblocking signals in
321 * process_pending_signals(). We depend on the FreeBSD behaivor here where
322 * this will only affect this thread's signal mask. We don't use
323 * pthread_sigmask which might seem more correct because that routine also
324 * does odd things with SIGCANCEL to implement pthread_cancel().
325 */
326 sigfillset(&set);
327 sigprocmask(SIG_SETMASK, &set, 0);
328
329 return qatomic_xchg(&ts->signal_pending, 1);
330 }
331
332 /* Returns 1 if given signal should dump core if not handled. */
333 static int core_dump_signal(int sig)
334 {
335 switch (sig) {
336 case TARGET_SIGABRT:
337 case TARGET_SIGFPE:
338 case TARGET_SIGILL:
339 case TARGET_SIGQUIT:
340 case TARGET_SIGSEGV:
341 case TARGET_SIGTRAP:
342 case TARGET_SIGBUS:
343 return 1;
344 default:
345 return 0;
346 }
347 }
348
349 /* Abort execution with signal. */
350 static G_NORETURN
351 void dump_core_and_abort(int target_sig)
352 {
353 CPUArchState *env = thread_cpu->env_ptr;
354 CPUState *cpu = env_cpu(env);
355 TaskState *ts = cpu->opaque;
356 int core_dumped = 0;
357 int host_sig;
358 struct sigaction act;
359
360 host_sig = target_to_host_signal(target_sig);
361 gdb_signalled(env, target_sig);
362
363 /* Dump core if supported by target binary format */
364 if (core_dump_signal(target_sig) && (ts->bprm->core_dump != NULL)) {
365 stop_all_tasks();
366 core_dumped =
367 ((*ts->bprm->core_dump)(target_sig, env) == 0);
368 }
369 if (core_dumped) {
370 struct rlimit nodump;
371
372 /*
373 * We already dumped the core of target process, we don't want
374 * a coredump of qemu itself.
375 */
376 getrlimit(RLIMIT_CORE, &nodump);
377 nodump.rlim_cur = 0;
378 setrlimit(RLIMIT_CORE, &nodump);
379 (void) fprintf(stderr, "qemu: uncaught target signal %d (%s) "
380 "- %s\n", target_sig, strsignal(host_sig), "core dumped");
381 }
382
383 /*
384 * The proper exit code for dying from an uncaught signal is
385 * -<signal>. The kernel doesn't allow exit() or _exit() to pass
386 * a negative value. To get the proper exit code we need to
387 * actually die from an uncaught signal. Here the default signal
388 * handler is installed, we send ourself a signal and we wait for
389 * it to arrive.
390 */
391 memset(&act, 0, sizeof(act));
392 sigfillset(&act.sa_mask);
393 act.sa_handler = SIG_DFL;
394 sigaction(host_sig, &act, NULL);
395
396 kill(getpid(), host_sig);
397
398 /*
399 * Make sure the signal isn't masked (just reuse the mask inside
400 * of act).
401 */
402 sigdelset(&act.sa_mask, host_sig);
403 sigsuspend(&act.sa_mask);
404
405 /* unreachable */
406 abort();
407 }
408
409 /*
410 * Queue a signal so that it will be send to the virtual CPU as soon as
411 * possible.
412 */
413 void queue_signal(CPUArchState *env, int sig, int si_type,
414 target_siginfo_t *info)
415 {
416 CPUState *cpu = env_cpu(env);
417 TaskState *ts = cpu->opaque;
418
419 trace_user_queue_signal(env, sig);
420
421 info->si_code = deposit32(info->si_code, 24, 8, si_type);
422
423 ts->sync_signal.info = *info;
424 ts->sync_signal.pending = sig;
425 /* Signal that a new signal is pending. */
426 qatomic_set(&ts->signal_pending, 1);
427 return;
428 }
429
430 static int fatal_signal(int sig)
431 {
432
433 switch (sig) {
434 case TARGET_SIGCHLD:
435 case TARGET_SIGURG:
436 case TARGET_SIGWINCH:
437 case TARGET_SIGINFO:
438 /* Ignored by default. */
439 return 0;
440 case TARGET_SIGCONT:
441 case TARGET_SIGSTOP:
442 case TARGET_SIGTSTP:
443 case TARGET_SIGTTIN:
444 case TARGET_SIGTTOU:
445 /* Job control signals. */
446 return 0;
447 default:
448 return 1;
449 }
450 }
451
452 /*
453 * Force a synchronously taken QEMU_SI_FAULT signal. For QEMU the
454 * 'force' part is handled in process_pending_signals().
455 */
456 void force_sig_fault(int sig, int code, abi_ulong addr)
457 {
458 CPUState *cpu = thread_cpu;
459 CPUArchState *env = cpu->env_ptr;
460 target_siginfo_t info = {};
461
462 info.si_signo = sig;
463 info.si_errno = 0;
464 info.si_code = code;
465 info.si_addr = addr;
466 queue_signal(env, sig, QEMU_SI_FAULT, &info);
467 }
468
469 static void host_signal_handler(int host_sig, siginfo_t *info, void *puc)
470 {
471 CPUArchState *env = thread_cpu->env_ptr;
472 CPUState *cpu = env_cpu(env);
473 TaskState *ts = cpu->opaque;
474 target_siginfo_t tinfo;
475 ucontext_t *uc = puc;
476 struct emulated_sigtable *k;
477 int guest_sig;
478 uintptr_t pc = 0;
479 bool sync_sig = false;
480
481 /*
482 * Non-spoofed SIGSEGV and SIGBUS are synchronous, and need special
483 * handling wrt signal blocking and unwinding.
484 */
485 if ((host_sig == SIGSEGV || host_sig == SIGBUS) && info->si_code > 0) {
486 MMUAccessType access_type;
487 uintptr_t host_addr;
488 abi_ptr guest_addr;
489 bool is_write;
490
491 host_addr = (uintptr_t)info->si_addr;
492
493 /*
494 * Convert forcefully to guest address space: addresses outside
495 * reserved_va are still valid to report via SEGV_MAPERR.
496 */
497 guest_addr = h2g_nocheck(host_addr);
498
499 pc = host_signal_pc(uc);
500 is_write = host_signal_write(info, uc);
501 access_type = adjust_signal_pc(&pc, is_write);
502
503 if (host_sig == SIGSEGV) {
504 bool maperr = true;
505
506 if (info->si_code == SEGV_ACCERR && h2g_valid(host_addr)) {
507 /* If this was a write to a TB protected page, restart. */
508 if (is_write &&
509 handle_sigsegv_accerr_write(cpu, &uc->uc_sigmask,
510 pc, guest_addr)) {
511 return;
512 }
513
514 /*
515 * With reserved_va, the whole address space is PROT_NONE,
516 * which means that we may get ACCERR when we want MAPERR.
517 */
518 if (page_get_flags(guest_addr) & PAGE_VALID) {
519 maperr = false;
520 } else {
521 info->si_code = SEGV_MAPERR;
522 }
523 }
524
525 sigprocmask(SIG_SETMASK, &uc->uc_sigmask, NULL);
526 cpu_loop_exit_sigsegv(cpu, guest_addr, access_type, maperr, pc);
527 } else {
528 sigprocmask(SIG_SETMASK, &uc->uc_sigmask, NULL);
529 if (info->si_code == BUS_ADRALN) {
530 cpu_loop_exit_sigbus(cpu, guest_addr, access_type, pc);
531 }
532 }
533
534 sync_sig = true;
535 }
536
537 /* Get the target signal number. */
538 guest_sig = host_to_target_signal(host_sig);
539 if (guest_sig < 1 || guest_sig > TARGET_NSIG) {
540 return;
541 }
542 trace_user_host_signal(cpu, host_sig, guest_sig);
543
544 host_to_target_siginfo_noswap(&tinfo, info);
545
546 k = &ts->sigtab[guest_sig - 1];
547 k->info = tinfo;
548 k->pending = guest_sig;
549 ts->signal_pending = 1;
550
551 /*
552 * For synchronous signals, unwind the cpu state to the faulting
553 * insn and then exit back to the main loop so that the signal
554 * is delivered immediately.
555 */
556 if (sync_sig) {
557 cpu->exception_index = EXCP_INTERRUPT;
558 cpu_loop_exit_restore(cpu, pc);
559 }
560
561 rewind_if_in_safe_syscall(puc);
562
563 /*
564 * Block host signals until target signal handler entered. We
565 * can't block SIGSEGV or SIGBUS while we're executing guest
566 * code in case the guest code provokes one in the window between
567 * now and it getting out to the main loop. Signals will be
568 * unblocked again in process_pending_signals().
569 */
570 sigfillset(&uc->uc_sigmask);
571 sigdelset(&uc->uc_sigmask, SIGSEGV);
572 sigdelset(&uc->uc_sigmask, SIGBUS);
573
574 /* Interrupt the virtual CPU as soon as possible. */
575 cpu_exit(thread_cpu);
576 }
577
578 /* do_sigaltstack() returns target values and errnos. */
579 /* compare to kern/kern_sig.c sys_sigaltstack() and kern_sigaltstack() */
580 abi_long do_sigaltstack(abi_ulong uss_addr, abi_ulong uoss_addr, abi_ulong sp)
581 {
582 TaskState *ts = (TaskState *)thread_cpu->opaque;
583 int ret;
584 target_stack_t oss;
585
586 if (uoss_addr) {
587 /* Save current signal stack params */
588 oss.ss_sp = tswapl(ts->sigaltstack_used.ss_sp);
589 oss.ss_size = tswapl(ts->sigaltstack_used.ss_size);
590 oss.ss_flags = tswapl(sas_ss_flags(ts, sp));
591 }
592
593 if (uss_addr) {
594 target_stack_t *uss;
595 target_stack_t ss;
596 size_t minstacksize = TARGET_MINSIGSTKSZ;
597
598 ret = -TARGET_EFAULT;
599 if (!lock_user_struct(VERIFY_READ, uss, uss_addr, 1)) {
600 goto out;
601 }
602 __get_user(ss.ss_sp, &uss->ss_sp);
603 __get_user(ss.ss_size, &uss->ss_size);
604 __get_user(ss.ss_flags, &uss->ss_flags);
605 unlock_user_struct(uss, uss_addr, 0);
606
607 ret = -TARGET_EPERM;
608 if (on_sig_stack(ts, sp)) {
609 goto out;
610 }
611
612 ret = -TARGET_EINVAL;
613 if (ss.ss_flags != TARGET_SS_DISABLE
614 && ss.ss_flags != TARGET_SS_ONSTACK
615 && ss.ss_flags != 0) {
616 goto out;
617 }
618
619 if (ss.ss_flags == TARGET_SS_DISABLE) {
620 ss.ss_size = 0;
621 ss.ss_sp = 0;
622 } else {
623 ret = -TARGET_ENOMEM;
624 if (ss.ss_size < minstacksize) {
625 goto out;
626 }
627 }
628
629 ts->sigaltstack_used.ss_sp = ss.ss_sp;
630 ts->sigaltstack_used.ss_size = ss.ss_size;
631 }
632
633 if (uoss_addr) {
634 ret = -TARGET_EFAULT;
635 if (copy_to_user(uoss_addr, &oss, sizeof(oss))) {
636 goto out;
637 }
638 }
639
640 ret = 0;
641 out:
642 return ret;
643 }
644
645 /* do_sigaction() return host values and errnos */
646 int do_sigaction(int sig, const struct target_sigaction *act,
647 struct target_sigaction *oact)
648 {
649 struct target_sigaction *k;
650 struct sigaction act1;
651 int host_sig;
652 int ret = 0;
653
654 if (sig < 1 || sig > TARGET_NSIG) {
655 return -TARGET_EINVAL;
656 }
657
658 if ((sig == TARGET_SIGKILL || sig == TARGET_SIGSTOP) &&
659 act != NULL && act->_sa_handler != TARGET_SIG_DFL) {
660 return -TARGET_EINVAL;
661 }
662
663 if (block_signals()) {
664 return -TARGET_ERESTART;
665 }
666
667 k = &sigact_table[sig - 1];
668 if (oact) {
669 oact->_sa_handler = tswapal(k->_sa_handler);
670 oact->sa_flags = tswap32(k->sa_flags);
671 oact->sa_mask = k->sa_mask;
672 }
673 if (act) {
674 k->_sa_handler = tswapal(act->_sa_handler);
675 k->sa_flags = tswap32(act->sa_flags);
676 k->sa_mask = act->sa_mask;
677
678 /* Update the host signal state. */
679 host_sig = target_to_host_signal(sig);
680 if (host_sig != SIGSEGV && host_sig != SIGBUS) {
681 memset(&act1, 0, sizeof(struct sigaction));
682 sigfillset(&act1.sa_mask);
683 act1.sa_flags = SA_SIGINFO;
684 if (k->sa_flags & TARGET_SA_RESTART) {
685 act1.sa_flags |= SA_RESTART;
686 }
687 /*
688 * Note: It is important to update the host kernel signal mask to
689 * avoid getting unexpected interrupted system calls.
690 */
691 if (k->_sa_handler == TARGET_SIG_IGN) {
692 act1.sa_sigaction = (void *)SIG_IGN;
693 } else if (k->_sa_handler == TARGET_SIG_DFL) {
694 if (fatal_signal(sig)) {
695 act1.sa_sigaction = host_signal_handler;
696 } else {
697 act1.sa_sigaction = (void *)SIG_DFL;
698 }
699 } else {
700 act1.sa_sigaction = host_signal_handler;
701 }
702 ret = sigaction(host_sig, &act1, NULL);
703 }
704 }
705 return ret;
706 }
707
708 static inline abi_ulong get_sigframe(struct target_sigaction *ka,
709 CPUArchState *env, size_t frame_size)
710 {
711 TaskState *ts = (TaskState *)thread_cpu->opaque;
712 abi_ulong sp;
713
714 /* Use default user stack */
715 sp = get_sp_from_cpustate(env);
716
717 if ((ka->sa_flags & TARGET_SA_ONSTACK) && sas_ss_flags(ts, sp) == 0) {
718 sp = ts->sigaltstack_used.ss_sp + ts->sigaltstack_used.ss_size;
719 }
720
721 /* TODO: make this a target_arch function / define */
722 #if defined(TARGET_ARM)
723 return (sp - frame_size) & ~7;
724 #elif defined(TARGET_AARCH64)
725 return (sp - frame_size) & ~15;
726 #else
727 return sp - frame_size;
728 #endif
729 }
730
731 /* compare to $M/$M/exec_machdep.c sendsig and sys/kern/kern_sig.c sigexit */
732
733 static void setup_frame(int sig, int code, struct target_sigaction *ka,
734 target_sigset_t *set, target_siginfo_t *tinfo, CPUArchState *env)
735 {
736 struct target_sigframe *frame;
737 abi_ulong frame_addr;
738 int i;
739
740 frame_addr = get_sigframe(ka, env, sizeof(*frame));
741 trace_user_setup_frame(env, frame_addr);
742 if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0)) {
743 unlock_user_struct(frame, frame_addr, 1);
744 dump_core_and_abort(TARGET_SIGILL);
745 return;
746 }
747
748 memset(frame, 0, sizeof(*frame));
749 setup_sigframe_arch(env, frame_addr, frame, 0);
750
751 for (i = 0; i < TARGET_NSIG_WORDS; i++) {
752 __put_user(set->__bits[i], &frame->sf_uc.uc_sigmask.__bits[i]);
753 }
754
755 if (tinfo) {
756 frame->sf_si.si_signo = tinfo->si_signo;
757 frame->sf_si.si_errno = tinfo->si_errno;
758 frame->sf_si.si_code = tinfo->si_code;
759 frame->sf_si.si_pid = tinfo->si_pid;
760 frame->sf_si.si_uid = tinfo->si_uid;
761 frame->sf_si.si_status = tinfo->si_status;
762 frame->sf_si.si_addr = tinfo->si_addr;
763 /* see host_to_target_siginfo_noswap() for more details */
764 frame->sf_si.si_value.sival_ptr = tinfo->si_value.sival_ptr;
765 /*
766 * At this point, whatever is in the _reason union is complete
767 * and in target order, so just copy the whole thing over, even
768 * if it's too large for this specific signal.
769 * host_to_target_siginfo_noswap() and tswap_siginfo() have ensured
770 * that's so.
771 */
772 memcpy(&frame->sf_si._reason, &tinfo->_reason,
773 sizeof(tinfo->_reason));
774 }
775
776 set_sigtramp_args(env, sig, frame, frame_addr, ka);
777
778 unlock_user_struct(frame, frame_addr, 1);
779 }
780
781 static int reset_signal_mask(target_ucontext_t *ucontext)
782 {
783 int i;
784 sigset_t blocked;
785 target_sigset_t target_set;
786 TaskState *ts = (TaskState *)thread_cpu->opaque;
787
788 for (i = 0; i < TARGET_NSIG_WORDS; i++) {
789 if (__get_user(target_set.__bits[i],
790 &ucontext->uc_sigmask.__bits[i])) {
791 return -TARGET_EFAULT;
792 }
793 }
794 target_to_host_sigset_internal(&blocked, &target_set);
795 ts->signal_mask = blocked;
796
797 return 0;
798 }
799
800 /* See sys/$M/$M/exec_machdep.c sigreturn() */
801 long do_sigreturn(CPUArchState *env, abi_ulong addr)
802 {
803 long ret;
804 abi_ulong target_ucontext;
805 target_ucontext_t *ucontext = NULL;
806
807 /* Get the target ucontext address from the stack frame */
808 ret = get_ucontext_sigreturn(env, addr, &target_ucontext);
809 if (is_error(ret)) {
810 return ret;
811 }
812 trace_user_do_sigreturn(env, addr);
813 if (!lock_user_struct(VERIFY_READ, ucontext, target_ucontext, 0)) {
814 goto badframe;
815 }
816
817 /* Set the register state back to before the signal. */
818 if (set_mcontext(env, &ucontext->uc_mcontext, 1)) {
819 goto badframe;
820 }
821
822 /* And reset the signal mask. */
823 if (reset_signal_mask(ucontext)) {
824 goto badframe;
825 }
826
827 unlock_user_struct(ucontext, target_ucontext, 0);
828 return -TARGET_EJUSTRETURN;
829
830 badframe:
831 if (ucontext != NULL) {
832 unlock_user_struct(ucontext, target_ucontext, 0);
833 }
834 return -TARGET_EFAULT;
835 }
836
837 void signal_init(void)
838 {
839 TaskState *ts = (TaskState *)thread_cpu->opaque;
840 struct sigaction act;
841 struct sigaction oact;
842 int i;
843 int host_sig;
844
845 /* Set the signal mask from the host mask. */
846 sigprocmask(0, 0, &ts->signal_mask);
847
848 sigfillset(&act.sa_mask);
849 act.sa_sigaction = host_signal_handler;
850 act.sa_flags = SA_SIGINFO;
851
852 for (i = 1; i <= TARGET_NSIG; i++) {
853 #ifdef CONFIG_GPROF
854 if (i == TARGET_SIGPROF) {
855 continue;
856 }
857 #endif
858 host_sig = target_to_host_signal(i);
859 sigaction(host_sig, NULL, &oact);
860 if (oact.sa_sigaction == (void *)SIG_IGN) {
861 sigact_table[i - 1]._sa_handler = TARGET_SIG_IGN;
862 } else if (oact.sa_sigaction == (void *)SIG_DFL) {
863 sigact_table[i - 1]._sa_handler = TARGET_SIG_DFL;
864 }
865 /*
866 * If there's already a handler installed then something has
867 * gone horribly wrong, so don't even try to handle that case.
868 * Install some handlers for our own use. We need at least
869 * SIGSEGV and SIGBUS, to detect exceptions. We can not just
870 * trap all signals because it affects syscall interrupt
871 * behavior. But do trap all default-fatal signals.
872 */
873 if (fatal_signal(i)) {
874 sigaction(host_sig, &act, NULL);
875 }
876 }
877 }
878
879 static void handle_pending_signal(CPUArchState *env, int sig,
880 struct emulated_sigtable *k)
881 {
882 CPUState *cpu = env_cpu(env);
883 TaskState *ts = cpu->opaque;
884 struct target_sigaction *sa;
885 int code;
886 sigset_t set;
887 abi_ulong handler;
888 target_siginfo_t tinfo;
889 target_sigset_t target_old_set;
890
891 trace_user_handle_signal(env, sig);
892
893 k->pending = 0;
894
895 sig = gdb_handlesig(cpu, sig);
896 if (!sig) {
897 sa = NULL;
898 handler = TARGET_SIG_IGN;
899 } else {
900 sa = &sigact_table[sig - 1];
901 handler = sa->_sa_handler;
902 }
903
904 if (do_strace) {
905 print_taken_signal(sig, &k->info);
906 }
907
908 if (handler == TARGET_SIG_DFL) {
909 /*
910 * default handler : ignore some signal. The other are job
911 * control or fatal.
912 */
913 if (sig == TARGET_SIGTSTP || sig == TARGET_SIGTTIN ||
914 sig == TARGET_SIGTTOU) {
915 kill(getpid(), SIGSTOP);
916 } else if (sig != TARGET_SIGCHLD && sig != TARGET_SIGURG &&
917 sig != TARGET_SIGINFO && sig != TARGET_SIGWINCH &&
918 sig != TARGET_SIGCONT) {
919 dump_core_and_abort(sig);
920 }
921 } else if (handler == TARGET_SIG_IGN) {
922 /* ignore sig */
923 } else if (handler == TARGET_SIG_ERR) {
924 dump_core_and_abort(sig);
925 } else {
926 /* compute the blocked signals during the handler execution */
927 sigset_t *blocked_set;
928
929 target_to_host_sigset(&set, &sa->sa_mask);
930 /*
931 * SA_NODEFER indicates that the current signal should not be
932 * blocked during the handler.
933 */
934 if (!(sa->sa_flags & TARGET_SA_NODEFER)) {
935 sigaddset(&set, target_to_host_signal(sig));
936 }
937
938 /*
939 * Save the previous blocked signal state to restore it at the
940 * end of the signal execution (see do_sigreturn).
941 */
942 host_to_target_sigset_internal(&target_old_set, &ts->signal_mask);
943
944 blocked_set = ts->in_sigsuspend ?
945 &ts->sigsuspend_mask : &ts->signal_mask;
946 sigorset(&ts->signal_mask, blocked_set, &set);
947 ts->in_sigsuspend = false;
948 sigprocmask(SIG_SETMASK, &ts->signal_mask, NULL);
949
950 /* XXX VM86 on x86 ??? */
951
952 code = k->info.si_code; /* From host, so no si_type */
953 /* prepare the stack frame of the virtual CPU */
954 if (sa->sa_flags & TARGET_SA_SIGINFO) {
955 tswap_siginfo(&tinfo, &k->info);
956 setup_frame(sig, code, sa, &target_old_set, &tinfo, env);
957 } else {
958 setup_frame(sig, code, sa, &target_old_set, NULL, env);
959 }
960 if (sa->sa_flags & TARGET_SA_RESETHAND) {
961 sa->_sa_handler = TARGET_SIG_DFL;
962 }
963 }
964 }
965
966 void process_pending_signals(CPUArchState *env)
967 {
968 CPUState *cpu = env_cpu(env);
969 int sig;
970 sigset_t *blocked_set, set;
971 struct emulated_sigtable *k;
972 TaskState *ts = cpu->opaque;
973
974 while (qatomic_read(&ts->signal_pending)) {
975 sigfillset(&set);
976 sigprocmask(SIG_SETMASK, &set, 0);
977
978 restart_scan:
979 sig = ts->sync_signal.pending;
980 if (sig) {
981 /*
982 * Synchronous signals are forced by the emulated CPU in some way.
983 * If they are set to ignore, restore the default handler (see
984 * sys/kern_sig.c trapsignal() and execsigs() for this behavior)
985 * though maybe this is done only when forcing exit for non SIGCHLD.
986 */
987 if (sigismember(&ts->signal_mask, target_to_host_signal(sig)) ||
988 sigact_table[sig - 1]._sa_handler == TARGET_SIG_IGN) {
989 sigdelset(&ts->signal_mask, target_to_host_signal(sig));
990 sigact_table[sig - 1]._sa_handler = TARGET_SIG_DFL;
991 }
992 handle_pending_signal(env, sig, &ts->sync_signal);
993 }
994
995 k = ts->sigtab;
996 for (sig = 1; sig <= TARGET_NSIG; sig++, k++) {
997 blocked_set = ts->in_sigsuspend ?
998 &ts->sigsuspend_mask : &ts->signal_mask;
999 if (k->pending &&
1000 !sigismember(blocked_set, target_to_host_signal(sig))) {
1001 handle_pending_signal(env, sig, k);
1002 /*
1003 * Restart scan from the beginning, as handle_pending_signal
1004 * might have resulted in a new synchronous signal (eg SIGSEGV).
1005 */
1006 goto restart_scan;
1007 }
1008 }
1009
1010 /*
1011 * Unblock signals and check one more time. Unblocking signals may cause
1012 * us to take another host signal, which will set signal_pending again.
1013 */
1014 qatomic_set(&ts->signal_pending, 0);
1015 ts->in_sigsuspend = false;
1016 set = ts->signal_mask;
1017 sigdelset(&set, SIGSEGV);
1018 sigdelset(&set, SIGBUS);
1019 sigprocmask(SIG_SETMASK, &set, 0);
1020 }
1021 ts->in_sigsuspend = false;
1022 }
1023
1024 void cpu_loop_exit_sigsegv(CPUState *cpu, target_ulong addr,
1025 MMUAccessType access_type, bool maperr, uintptr_t ra)
1026 {
1027 const struct TCGCPUOps *tcg_ops = CPU_GET_CLASS(cpu)->tcg_ops;
1028
1029 if (tcg_ops->record_sigsegv) {
1030 tcg_ops->record_sigsegv(cpu, addr, access_type, maperr, ra);
1031 }
1032
1033 force_sig_fault(TARGET_SIGSEGV,
1034 maperr ? TARGET_SEGV_MAPERR : TARGET_SEGV_ACCERR,
1035 addr);
1036 cpu->exception_index = EXCP_INTERRUPT;
1037 cpu_loop_exit_restore(cpu, ra);
1038 }
1039
1040 void cpu_loop_exit_sigbus(CPUState *cpu, target_ulong addr,
1041 MMUAccessType access_type, uintptr_t ra)
1042 {
1043 const struct TCGCPUOps *tcg_ops = CPU_GET_CLASS(cpu)->tcg_ops;
1044
1045 if (tcg_ops->record_sigbus) {
1046 tcg_ops->record_sigbus(cpu, addr, access_type, ra);
1047 }
1048
1049 force_sig_fault(TARGET_SIGBUS, TARGET_BUS_ADRALN, addr);
1050 cpu->exception_index = EXCP_INTERRUPT;
1051 cpu_loop_exit_restore(cpu, ra);
1052 }