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