1 /* 2 * Emulation of Linux signals 3 * 4 * Copyright (c) 2003 Fabrice Bellard 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License as published by 8 * the Free Software Foundation; either version 2 of the License, or 9 * (at your option) any later version. 10 * 11 * This program is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 * GNU General Public License for more details. 15 * 16 * You should have received a copy of the GNU General Public License 17 * along with this program; if not, see <http://www.gnu.org/licenses/>. 18 */ 19 #include "qemu/osdep.h" 20 #include "qemu/bitops.h" 21 #include "qemu/cutils.h" 22 #include "gdbstub/user.h" 23 #include "exec/page-protection.h" 24 #include "accel/tcg/cpu-ops.h" 25 26 #include <sys/ucontext.h> 27 #include <sys/resource.h> 28 29 #include "qemu.h" 30 #include "user-internals.h" 31 #include "strace.h" 32 #include "loader.h" 33 #include "trace.h" 34 #include "signal-common.h" 35 #include "host-signal.h" 36 #include "user/cpu_loop.h" 37 #include "user/page-protection.h" 38 #include "user/safe-syscall.h" 39 #include "user/signal.h" 40 #include "tcg/tcg.h" 41 42 /* target_siginfo_t must fit in gdbstub's siginfo save area. */ 43 QEMU_BUILD_BUG_ON(sizeof(target_siginfo_t) > MAX_SIGINFO_LENGTH); 44 45 static struct target_sigaction sigact_table[TARGET_NSIG]; 46 47 static void host_signal_handler(int host_signum, siginfo_t *info, 48 void *puc); 49 50 /* Fallback addresses into sigtramp page. */ 51 abi_ulong default_sigreturn; 52 abi_ulong default_rt_sigreturn; 53 54 /* 55 * System includes define _NSIG as SIGRTMAX + 1, but qemu (like the kernel) 56 * defines TARGET_NSIG as TARGET_SIGRTMAX and the first signal is 1. 57 * Signal number 0 is reserved for use as kill(pid, 0), to test whether 58 * a process exists without sending it a signal. 59 */ 60 #ifdef __SIGRTMAX 61 QEMU_BUILD_BUG_ON(__SIGRTMAX + 1 != _NSIG); 62 #endif 63 static uint8_t host_to_target_signal_table[_NSIG] = { 64 #define MAKE_SIG_ENTRY(sig) [sig] = TARGET_##sig, 65 MAKE_SIGNAL_LIST 66 #undef MAKE_SIG_ENTRY 67 }; 68 69 static uint8_t target_to_host_signal_table[TARGET_NSIG + 1]; 70 71 /* valid sig is between 1 and _NSIG - 1 */ 72 int host_to_target_signal(int sig) 73 { 74 if (sig < 1) { 75 return sig; 76 } 77 if (sig >= _NSIG) { 78 return TARGET_NSIG + 1; 79 } 80 return host_to_target_signal_table[sig]; 81 } 82 83 /* valid sig is between 1 and TARGET_NSIG */ 84 int target_to_host_signal(int sig) 85 { 86 if (sig < 1) { 87 return sig; 88 } 89 if (sig > TARGET_NSIG) { 90 return _NSIG; 91 } 92 return target_to_host_signal_table[sig]; 93 } 94 95 static inline void target_sigaddset(target_sigset_t *set, int signum) 96 { 97 signum--; 98 abi_ulong mask = (abi_ulong)1 << (signum % TARGET_NSIG_BPW); 99 set->sig[signum / TARGET_NSIG_BPW] |= mask; 100 } 101 102 static inline int target_sigismember(const target_sigset_t *set, int signum) 103 { 104 signum--; 105 abi_ulong mask = (abi_ulong)1 << (signum % TARGET_NSIG_BPW); 106 return ((set->sig[signum / TARGET_NSIG_BPW] & mask) != 0); 107 } 108 109 void host_to_target_sigset_internal(target_sigset_t *d, 110 const sigset_t *s) 111 { 112 int host_sig, target_sig; 113 target_sigemptyset(d); 114 for (host_sig = 1; host_sig < _NSIG; host_sig++) { 115 target_sig = host_to_target_signal(host_sig); 116 if (target_sig < 1 || target_sig > TARGET_NSIG) { 117 continue; 118 } 119 if (sigismember(s, host_sig)) { 120 target_sigaddset(d, target_sig); 121 } 122 } 123 } 124 125 void host_to_target_sigset(target_sigset_t *d, const sigset_t *s) 126 { 127 target_sigset_t d1; 128 int i; 129 130 host_to_target_sigset_internal(&d1, s); 131 for(i = 0;i < TARGET_NSIG_WORDS; i++) 132 d->sig[i] = tswapal(d1.sig[i]); 133 } 134 135 void target_to_host_sigset_internal(sigset_t *d, 136 const target_sigset_t *s) 137 { 138 int host_sig, target_sig; 139 sigemptyset(d); 140 for (target_sig = 1; target_sig <= TARGET_NSIG; target_sig++) { 141 host_sig = target_to_host_signal(target_sig); 142 if (host_sig < 1 || host_sig >= _NSIG) { 143 continue; 144 } 145 if (target_sigismember(s, target_sig)) { 146 sigaddset(d, host_sig); 147 } 148 } 149 } 150 151 void target_to_host_sigset(sigset_t *d, const target_sigset_t *s) 152 { 153 target_sigset_t s1; 154 int i; 155 156 for(i = 0;i < TARGET_NSIG_WORDS; i++) 157 s1.sig[i] = tswapal(s->sig[i]); 158 target_to_host_sigset_internal(d, &s1); 159 } 160 161 void host_to_target_old_sigset(abi_ulong *old_sigset, 162 const sigset_t *sigset) 163 { 164 target_sigset_t d; 165 host_to_target_sigset(&d, sigset); 166 *old_sigset = d.sig[0]; 167 } 168 169 void target_to_host_old_sigset(sigset_t *sigset, 170 const abi_ulong *old_sigset) 171 { 172 target_sigset_t d; 173 int i; 174 175 d.sig[0] = *old_sigset; 176 for(i = 1;i < TARGET_NSIG_WORDS; i++) 177 d.sig[i] = 0; 178 target_to_host_sigset(sigset, &d); 179 } 180 181 int block_signals(void) 182 { 183 TaskState *ts = get_task_state(thread_cpu); 184 sigset_t set; 185 186 /* It's OK to block everything including SIGSEGV, because we won't 187 * run any further guest code before unblocking signals in 188 * process_pending_signals(). 189 */ 190 sigfillset(&set); 191 sigprocmask(SIG_SETMASK, &set, 0); 192 193 return qatomic_xchg(&ts->signal_pending, 1); 194 } 195 196 /* Wrapper for sigprocmask function 197 * Emulates a sigprocmask in a safe way for the guest. Note that set and oldset 198 * are host signal set, not guest ones. Returns -QEMU_ERESTARTSYS if 199 * a signal was already pending and the syscall must be restarted, or 200 * 0 on success. 201 * If set is NULL, this is guaranteed not to fail. 202 */ 203 int do_sigprocmask(int how, const sigset_t *set, sigset_t *oldset) 204 { 205 TaskState *ts = get_task_state(thread_cpu); 206 207 if (oldset) { 208 *oldset = ts->signal_mask; 209 } 210 211 if (set) { 212 int i; 213 214 if (block_signals()) { 215 return -QEMU_ERESTARTSYS; 216 } 217 218 switch (how) { 219 case SIG_BLOCK: 220 sigorset(&ts->signal_mask, &ts->signal_mask, set); 221 break; 222 case SIG_UNBLOCK: 223 for (i = 1; i <= NSIG; ++i) { 224 if (sigismember(set, i)) { 225 sigdelset(&ts->signal_mask, i); 226 } 227 } 228 break; 229 case SIG_SETMASK: 230 ts->signal_mask = *set; 231 break; 232 default: 233 g_assert_not_reached(); 234 } 235 236 /* Silently ignore attempts to change blocking status of KILL or STOP */ 237 sigdelset(&ts->signal_mask, SIGKILL); 238 sigdelset(&ts->signal_mask, SIGSTOP); 239 } 240 return 0; 241 } 242 243 /* Just set the guest's signal mask to the specified value; the 244 * caller is assumed to have called block_signals() already. 245 */ 246 void set_sigmask(const sigset_t *set) 247 { 248 TaskState *ts = get_task_state(thread_cpu); 249 250 ts->signal_mask = *set; 251 } 252 253 /* sigaltstack management */ 254 255 int on_sig_stack(unsigned long sp) 256 { 257 TaskState *ts = get_task_state(thread_cpu); 258 259 return (sp - ts->sigaltstack_used.ss_sp 260 < ts->sigaltstack_used.ss_size); 261 } 262 263 int sas_ss_flags(unsigned long sp) 264 { 265 TaskState *ts = get_task_state(thread_cpu); 266 267 return (ts->sigaltstack_used.ss_size == 0 ? SS_DISABLE 268 : on_sig_stack(sp) ? SS_ONSTACK : 0); 269 } 270 271 abi_ulong target_sigsp(abi_ulong sp, struct target_sigaction *ka) 272 { 273 /* 274 * This is the X/Open sanctioned signal stack switching. 275 */ 276 TaskState *ts = get_task_state(thread_cpu); 277 278 if ((ka->sa_flags & TARGET_SA_ONSTACK) && !sas_ss_flags(sp)) { 279 return ts->sigaltstack_used.ss_sp + ts->sigaltstack_used.ss_size; 280 } 281 return sp; 282 } 283 284 void target_save_altstack(target_stack_t *uss, CPUArchState *env) 285 { 286 TaskState *ts = get_task_state(thread_cpu); 287 288 __put_user(ts->sigaltstack_used.ss_sp, &uss->ss_sp); 289 __put_user(sas_ss_flags(get_sp_from_cpustate(env)), &uss->ss_flags); 290 __put_user(ts->sigaltstack_used.ss_size, &uss->ss_size); 291 } 292 293 abi_long target_restore_altstack(target_stack_t *uss, CPUArchState *env) 294 { 295 TaskState *ts = get_task_state(thread_cpu); 296 size_t minstacksize = TARGET_MINSIGSTKSZ; 297 target_stack_t ss; 298 299 #if defined(TARGET_PPC64) 300 /* ELF V2 for PPC64 has a 4K minimum stack size for signal handlers */ 301 struct image_info *image = ts->info; 302 if (get_ppc64_abi(image) > 1) { 303 minstacksize = 4096; 304 } 305 #endif 306 307 __get_user(ss.ss_sp, &uss->ss_sp); 308 __get_user(ss.ss_size, &uss->ss_size); 309 __get_user(ss.ss_flags, &uss->ss_flags); 310 311 if (on_sig_stack(get_sp_from_cpustate(env))) { 312 return -TARGET_EPERM; 313 } 314 315 switch (ss.ss_flags) { 316 default: 317 return -TARGET_EINVAL; 318 319 case TARGET_SS_DISABLE: 320 ss.ss_size = 0; 321 ss.ss_sp = 0; 322 break; 323 324 case TARGET_SS_ONSTACK: 325 case 0: 326 if (ss.ss_size < minstacksize) { 327 return -TARGET_ENOMEM; 328 } 329 break; 330 } 331 332 ts->sigaltstack_used.ss_sp = ss.ss_sp; 333 ts->sigaltstack_used.ss_size = ss.ss_size; 334 return 0; 335 } 336 337 /* siginfo conversion */ 338 339 static inline void host_to_target_siginfo_noswap(target_siginfo_t *tinfo, 340 const siginfo_t *info) 341 { 342 int sig = host_to_target_signal(info->si_signo); 343 int si_code = info->si_code; 344 int si_type; 345 tinfo->si_signo = sig; 346 tinfo->si_errno = 0; 347 tinfo->si_code = info->si_code; 348 349 /* This memset serves two purposes: 350 * (1) ensure we don't leak random junk to the guest later 351 * (2) placate false positives from gcc about fields 352 * being used uninitialized if it chooses to inline both this 353 * function and tswap_siginfo() into host_to_target_siginfo(). 354 */ 355 memset(tinfo->_sifields._pad, 0, sizeof(tinfo->_sifields._pad)); 356 357 /* This is awkward, because we have to use a combination of 358 * the si_code and si_signo to figure out which of the union's 359 * members are valid. (Within the host kernel it is always possible 360 * to tell, but the kernel carefully avoids giving userspace the 361 * high 16 bits of si_code, so we don't have the information to 362 * do this the easy way...) We therefore make our best guess, 363 * bearing in mind that a guest can spoof most of the si_codes 364 * via rt_sigqueueinfo() if it likes. 365 * 366 * Once we have made our guess, we record it in the top 16 bits of 367 * the si_code, so that tswap_siginfo() later can use it. 368 * tswap_siginfo() will strip these top bits out before writing 369 * si_code to the guest (sign-extending the lower bits). 370 */ 371 372 switch (si_code) { 373 case SI_USER: 374 case SI_TKILL: 375 case SI_KERNEL: 376 /* Sent via kill(), tkill() or tgkill(), or direct from the kernel. 377 * These are the only unspoofable si_code values. 378 */ 379 tinfo->_sifields._kill._pid = info->si_pid; 380 tinfo->_sifields._kill._uid = info->si_uid; 381 si_type = QEMU_SI_KILL; 382 break; 383 default: 384 /* Everything else is spoofable. Make best guess based on signal */ 385 switch (sig) { 386 case TARGET_SIGCHLD: 387 tinfo->_sifields._sigchld._pid = info->si_pid; 388 tinfo->_sifields._sigchld._uid = info->si_uid; 389 if (si_code == CLD_EXITED) 390 tinfo->_sifields._sigchld._status = info->si_status; 391 else 392 tinfo->_sifields._sigchld._status 393 = host_to_target_signal(info->si_status & 0x7f) 394 | (info->si_status & ~0x7f); 395 tinfo->_sifields._sigchld._utime = info->si_utime; 396 tinfo->_sifields._sigchld._stime = info->si_stime; 397 si_type = QEMU_SI_CHLD; 398 break; 399 case TARGET_SIGIO: 400 tinfo->_sifields._sigpoll._band = info->si_band; 401 tinfo->_sifields._sigpoll._fd = info->si_fd; 402 si_type = QEMU_SI_POLL; 403 break; 404 default: 405 /* Assume a sigqueue()/mq_notify()/rt_sigqueueinfo() source. */ 406 tinfo->_sifields._rt._pid = info->si_pid; 407 tinfo->_sifields._rt._uid = info->si_uid; 408 /* XXX: potential problem if 64 bit */ 409 tinfo->_sifields._rt._sigval.sival_ptr 410 = (abi_ulong)(unsigned long)info->si_value.sival_ptr; 411 si_type = QEMU_SI_RT; 412 break; 413 } 414 break; 415 } 416 417 tinfo->si_code = deposit32(si_code, 16, 16, si_type); 418 } 419 420 static void tswap_siginfo(target_siginfo_t *tinfo, 421 const target_siginfo_t *info) 422 { 423 int si_type = extract32(info->si_code, 16, 16); 424 int si_code = sextract32(info->si_code, 0, 16); 425 426 __put_user(info->si_signo, &tinfo->si_signo); 427 __put_user(info->si_errno, &tinfo->si_errno); 428 __put_user(si_code, &tinfo->si_code); 429 430 /* We can use our internal marker of which fields in the structure 431 * are valid, rather than duplicating the guesswork of 432 * host_to_target_siginfo_noswap() here. 433 */ 434 switch (si_type) { 435 case QEMU_SI_KILL: 436 __put_user(info->_sifields._kill._pid, &tinfo->_sifields._kill._pid); 437 __put_user(info->_sifields._kill._uid, &tinfo->_sifields._kill._uid); 438 break; 439 case QEMU_SI_TIMER: 440 __put_user(info->_sifields._timer._timer1, 441 &tinfo->_sifields._timer._timer1); 442 __put_user(info->_sifields._timer._timer2, 443 &tinfo->_sifields._timer._timer2); 444 break; 445 case QEMU_SI_POLL: 446 __put_user(info->_sifields._sigpoll._band, 447 &tinfo->_sifields._sigpoll._band); 448 __put_user(info->_sifields._sigpoll._fd, 449 &tinfo->_sifields._sigpoll._fd); 450 break; 451 case QEMU_SI_FAULT: 452 __put_user(info->_sifields._sigfault._addr, 453 &tinfo->_sifields._sigfault._addr); 454 break; 455 case QEMU_SI_CHLD: 456 __put_user(info->_sifields._sigchld._pid, 457 &tinfo->_sifields._sigchld._pid); 458 __put_user(info->_sifields._sigchld._uid, 459 &tinfo->_sifields._sigchld._uid); 460 __put_user(info->_sifields._sigchld._status, 461 &tinfo->_sifields._sigchld._status); 462 __put_user(info->_sifields._sigchld._utime, 463 &tinfo->_sifields._sigchld._utime); 464 __put_user(info->_sifields._sigchld._stime, 465 &tinfo->_sifields._sigchld._stime); 466 break; 467 case QEMU_SI_RT: 468 __put_user(info->_sifields._rt._pid, &tinfo->_sifields._rt._pid); 469 __put_user(info->_sifields._rt._uid, &tinfo->_sifields._rt._uid); 470 __put_user(info->_sifields._rt._sigval.sival_ptr, 471 &tinfo->_sifields._rt._sigval.sival_ptr); 472 break; 473 default: 474 g_assert_not_reached(); 475 } 476 } 477 478 void host_to_target_siginfo(target_siginfo_t *tinfo, const siginfo_t *info) 479 { 480 target_siginfo_t tgt_tmp; 481 host_to_target_siginfo_noswap(&tgt_tmp, info); 482 tswap_siginfo(tinfo, &tgt_tmp); 483 } 484 485 /* XXX: we support only POSIX RT signals are used. */ 486 /* XXX: find a solution for 64 bit (additional malloced data is needed) */ 487 void target_to_host_siginfo(siginfo_t *info, const target_siginfo_t *tinfo) 488 { 489 /* This conversion is used only for the rt_sigqueueinfo syscall, 490 * and so we know that the _rt fields are the valid ones. 491 */ 492 abi_ulong sival_ptr; 493 494 __get_user(info->si_signo, &tinfo->si_signo); 495 __get_user(info->si_errno, &tinfo->si_errno); 496 __get_user(info->si_code, &tinfo->si_code); 497 __get_user(info->si_pid, &tinfo->_sifields._rt._pid); 498 __get_user(info->si_uid, &tinfo->_sifields._rt._uid); 499 __get_user(sival_ptr, &tinfo->_sifields._rt._sigval.sival_ptr); 500 info->si_value.sival_ptr = (void *)(long)sival_ptr; 501 } 502 503 /* returns 1 if given signal should dump core if not handled */ 504 static int core_dump_signal(int sig) 505 { 506 switch (sig) { 507 case TARGET_SIGABRT: 508 case TARGET_SIGFPE: 509 case TARGET_SIGILL: 510 case TARGET_SIGQUIT: 511 case TARGET_SIGSEGV: 512 case TARGET_SIGTRAP: 513 case TARGET_SIGBUS: 514 return (1); 515 default: 516 return (0); 517 } 518 } 519 520 int host_interrupt_signal; 521 522 static void signal_table_init(const char *rtsig_map) 523 { 524 int hsig, tsig, count; 525 526 if (rtsig_map) { 527 /* 528 * Map host RT signals to target RT signals according to the 529 * user-provided specification. 530 */ 531 const char *s = rtsig_map; 532 533 while (true) { 534 int i; 535 536 if (qemu_strtoi(s, &s, 10, &tsig) || *s++ != ' ') { 537 fprintf(stderr, "Malformed target signal in QEMU_RTSIG_MAP\n"); 538 exit(EXIT_FAILURE); 539 } 540 if (qemu_strtoi(s, &s, 10, &hsig) || *s++ != ' ') { 541 fprintf(stderr, "Malformed host signal in QEMU_RTSIG_MAP\n"); 542 exit(EXIT_FAILURE); 543 } 544 if (qemu_strtoi(s, &s, 10, &count) || (*s && *s != ',')) { 545 fprintf(stderr, "Malformed signal count in QEMU_RTSIG_MAP\n"); 546 exit(EXIT_FAILURE); 547 } 548 549 for (i = 0; i < count; i++, tsig++, hsig++) { 550 if (tsig < TARGET_SIGRTMIN || tsig > TARGET_NSIG) { 551 fprintf(stderr, "%d is not a target rt signal\n", tsig); 552 exit(EXIT_FAILURE); 553 } 554 if (hsig < SIGRTMIN || hsig > SIGRTMAX) { 555 fprintf(stderr, "%d is not a host rt signal\n", hsig); 556 exit(EXIT_FAILURE); 557 } 558 if (host_to_target_signal_table[hsig]) { 559 fprintf(stderr, "%d already maps %d\n", 560 hsig, host_to_target_signal_table[hsig]); 561 exit(EXIT_FAILURE); 562 } 563 host_to_target_signal_table[hsig] = tsig; 564 } 565 566 if (*s) { 567 s++; 568 } else { 569 break; 570 } 571 } 572 } else { 573 /* 574 * Default host-to-target RT signal mapping. 575 * 576 * Signals are supported starting from TARGET_SIGRTMIN and going up 577 * until we run out of host realtime signals. Glibc uses the lower 2 578 * RT signals and (hopefully) nobody uses the upper ones. 579 * This is why SIGRTMIN (34) is generally greater than __SIGRTMIN (32). 580 * To fix this properly we would need to do manual signal delivery 581 * multiplexed over a single host signal. 582 * Attempts for configure "missing" signals via sigaction will be 583 * silently ignored. 584 * 585 * Reserve two signals for internal usage (see below). 586 */ 587 588 hsig = SIGRTMIN + 2; 589 for (tsig = TARGET_SIGRTMIN; 590 hsig <= SIGRTMAX && tsig <= TARGET_NSIG; 591 hsig++, tsig++) { 592 host_to_target_signal_table[hsig] = tsig; 593 } 594 } 595 596 /* 597 * Remap the target SIGABRT, so that we can distinguish host abort 598 * from guest abort. When the guest registers a signal handler or 599 * calls raise(SIGABRT), the host will raise SIG_RTn. If the guest 600 * arrives at dump_core_and_abort(), we will map back to host SIGABRT 601 * so that the parent (native or emulated) sees the correct signal. 602 * Finally, also map host to guest SIGABRT so that the emulated 603 * parent sees the correct mapping from wait status. 604 */ 605 606 host_to_target_signal_table[SIGABRT] = 0; 607 for (hsig = SIGRTMIN; hsig <= SIGRTMAX; hsig++) { 608 if (!host_to_target_signal_table[hsig]) { 609 if (host_interrupt_signal) { 610 host_to_target_signal_table[hsig] = TARGET_SIGABRT; 611 break; 612 } else { 613 host_interrupt_signal = hsig; 614 } 615 } 616 } 617 if (hsig > SIGRTMAX) { 618 fprintf(stderr, 619 "No rt signals left for interrupt and SIGABRT mapping\n"); 620 exit(EXIT_FAILURE); 621 } 622 623 /* Invert the mapping that has already been assigned. */ 624 for (hsig = 1; hsig < _NSIG; hsig++) { 625 tsig = host_to_target_signal_table[hsig]; 626 if (tsig) { 627 if (target_to_host_signal_table[tsig]) { 628 fprintf(stderr, "%d is already mapped to %d\n", 629 tsig, target_to_host_signal_table[tsig]); 630 exit(EXIT_FAILURE); 631 } 632 target_to_host_signal_table[tsig] = hsig; 633 } 634 } 635 636 host_to_target_signal_table[SIGABRT] = TARGET_SIGABRT; 637 638 /* Map everything else out-of-bounds. */ 639 for (hsig = 1; hsig < _NSIG; hsig++) { 640 if (host_to_target_signal_table[hsig] == 0) { 641 host_to_target_signal_table[hsig] = TARGET_NSIG + 1; 642 } 643 } 644 for (count = 0, tsig = 1; tsig <= TARGET_NSIG; tsig++) { 645 if (target_to_host_signal_table[tsig] == 0) { 646 target_to_host_signal_table[tsig] = _NSIG; 647 count++; 648 } 649 } 650 651 trace_signal_table_init(count); 652 } 653 654 void signal_init(const char *rtsig_map) 655 { 656 TaskState *ts = get_task_state(thread_cpu); 657 struct sigaction act, oact; 658 659 /* initialize signal conversion tables */ 660 signal_table_init(rtsig_map); 661 662 /* Set the signal mask from the host mask. */ 663 sigprocmask(0, 0, &ts->signal_mask); 664 665 sigfillset(&act.sa_mask); 666 act.sa_flags = SA_SIGINFO; 667 act.sa_sigaction = host_signal_handler; 668 669 /* 670 * A parent process may configure ignored signals, but all other 671 * signals are default. For any target signals that have no host 672 * mapping, set to ignore. For all core_dump_signal, install our 673 * host signal handler so that we may invoke dump_core_and_abort. 674 * This includes SIGSEGV and SIGBUS, which are also need our signal 675 * handler for paging and exceptions. 676 */ 677 for (int tsig = 1; tsig <= TARGET_NSIG; tsig++) { 678 int hsig = target_to_host_signal(tsig); 679 abi_ptr thand = TARGET_SIG_IGN; 680 681 if (hsig >= _NSIG) { 682 continue; 683 } 684 685 /* As we force remap SIGABRT, cannot probe and install in one step. */ 686 if (tsig == TARGET_SIGABRT) { 687 sigaction(SIGABRT, NULL, &oact); 688 sigaction(hsig, &act, NULL); 689 } else { 690 struct sigaction *iact = core_dump_signal(tsig) ? &act : NULL; 691 sigaction(hsig, iact, &oact); 692 } 693 694 if (oact.sa_sigaction != (void *)SIG_IGN) { 695 thand = TARGET_SIG_DFL; 696 } 697 sigact_table[tsig - 1]._sa_handler = thand; 698 } 699 700 sigaction(host_interrupt_signal, &act, NULL); 701 } 702 703 /* Force a synchronously taken signal. The kernel force_sig() function 704 * also forces the signal to "not blocked, not ignored", but for QEMU 705 * that work is done in process_pending_signals(). 706 */ 707 void force_sig(int sig) 708 { 709 CPUState *cpu = thread_cpu; 710 target_siginfo_t info = {}; 711 712 info.si_signo = sig; 713 info.si_errno = 0; 714 info.si_code = TARGET_SI_KERNEL; 715 info._sifields._kill._pid = 0; 716 info._sifields._kill._uid = 0; 717 queue_signal(cpu_env(cpu), info.si_signo, QEMU_SI_KILL, &info); 718 } 719 720 /* 721 * Force a synchronously taken QEMU_SI_FAULT signal. For QEMU the 722 * 'force' part is handled in process_pending_signals(). 723 */ 724 void force_sig_fault(int sig, int code, abi_ulong addr) 725 { 726 CPUState *cpu = thread_cpu; 727 target_siginfo_t info = {}; 728 729 info.si_signo = sig; 730 info.si_errno = 0; 731 info.si_code = code; 732 info._sifields._sigfault._addr = addr; 733 queue_signal(cpu_env(cpu), sig, QEMU_SI_FAULT, &info); 734 } 735 736 /* Force a SIGSEGV if we couldn't write to memory trying to set 737 * up the signal frame. oldsig is the signal we were trying to handle 738 * at the point of failure. 739 */ 740 #if !defined(TARGET_RISCV) 741 void force_sigsegv(int oldsig) 742 { 743 if (oldsig == SIGSEGV) { 744 /* Make sure we don't try to deliver the signal again; this will 745 * end up with handle_pending_signal() calling dump_core_and_abort(). 746 */ 747 sigact_table[oldsig - 1]._sa_handler = TARGET_SIG_DFL; 748 } 749 force_sig(TARGET_SIGSEGV); 750 } 751 #endif 752 753 void cpu_loop_exit_sigsegv(CPUState *cpu, target_ulong addr, 754 MMUAccessType access_type, bool maperr, uintptr_t ra) 755 { 756 const TCGCPUOps *tcg_ops = CPU_GET_CLASS(cpu)->tcg_ops; 757 758 if (tcg_ops->record_sigsegv) { 759 tcg_ops->record_sigsegv(cpu, addr, access_type, maperr, ra); 760 } 761 762 force_sig_fault(TARGET_SIGSEGV, 763 maperr ? TARGET_SEGV_MAPERR : TARGET_SEGV_ACCERR, 764 addr); 765 cpu->exception_index = EXCP_INTERRUPT; 766 cpu_loop_exit_restore(cpu, ra); 767 } 768 769 void cpu_loop_exit_sigbus(CPUState *cpu, target_ulong addr, 770 MMUAccessType access_type, uintptr_t ra) 771 { 772 const TCGCPUOps *tcg_ops = CPU_GET_CLASS(cpu)->tcg_ops; 773 774 if (tcg_ops->record_sigbus) { 775 tcg_ops->record_sigbus(cpu, addr, access_type, ra); 776 } 777 778 force_sig_fault(TARGET_SIGBUS, TARGET_BUS_ADRALN, addr); 779 cpu->exception_index = EXCP_INTERRUPT; 780 cpu_loop_exit_restore(cpu, ra); 781 } 782 783 /* abort execution with signal */ 784 static G_NORETURN 785 void die_with_signal(int host_sig) 786 { 787 struct sigaction act = { 788 .sa_handler = SIG_DFL, 789 }; 790 791 /* 792 * The proper exit code for dying from an uncaught signal is -<signal>. 793 * The kernel doesn't allow exit() or _exit() to pass a negative value. 794 * To get the proper exit code we need to actually die from an uncaught 795 * signal. Here the default signal handler is installed, we send 796 * the signal and we wait for it to arrive. 797 */ 798 sigfillset(&act.sa_mask); 799 sigaction(host_sig, &act, NULL); 800 801 kill(getpid(), host_sig); 802 803 /* Make sure the signal isn't masked (reusing the mask inside of act). */ 804 sigdelset(&act.sa_mask, host_sig); 805 sigsuspend(&act.sa_mask); 806 807 /* unreachable */ 808 _exit(EXIT_FAILURE); 809 } 810 811 static G_NORETURN 812 void dump_core_and_abort(CPUArchState *env, int target_sig) 813 { 814 CPUState *cpu = env_cpu(env); 815 TaskState *ts = get_task_state(cpu); 816 int host_sig, core_dumped = 0; 817 818 /* On exit, undo the remapping of SIGABRT. */ 819 if (target_sig == TARGET_SIGABRT) { 820 host_sig = SIGABRT; 821 } else { 822 host_sig = target_to_host_signal(target_sig); 823 } 824 trace_user_dump_core_and_abort(env, target_sig, host_sig); 825 gdb_signalled(env, target_sig); 826 827 /* dump core if supported by target binary format */ 828 if (core_dump_signal(target_sig) && (ts->bprm->core_dump != NULL)) { 829 stop_all_tasks(); 830 core_dumped = 831 ((*ts->bprm->core_dump)(target_sig, env) == 0); 832 } 833 if (core_dumped) { 834 /* we already dumped the core of target process, we don't want 835 * a coredump of qemu itself */ 836 struct rlimit nodump; 837 getrlimit(RLIMIT_CORE, &nodump); 838 nodump.rlim_cur=0; 839 setrlimit(RLIMIT_CORE, &nodump); 840 (void) fprintf(stderr, "qemu: uncaught target signal %d (%s) - %s\n", 841 target_sig, strsignal(host_sig), "core dumped" ); 842 } 843 844 preexit_cleanup(env, 128 + target_sig); 845 die_with_signal(host_sig); 846 } 847 848 /* queue a signal so that it will be send to the virtual CPU as soon 849 as possible */ 850 void queue_signal(CPUArchState *env, int sig, int si_type, 851 target_siginfo_t *info) 852 { 853 CPUState *cpu = env_cpu(env); 854 TaskState *ts = get_task_state(cpu); 855 856 trace_user_queue_signal(env, sig); 857 858 info->si_code = deposit32(info->si_code, 16, 16, si_type); 859 860 ts->sync_signal.info = *info; 861 ts->sync_signal.pending = sig; 862 /* signal that a new signal is pending */ 863 qatomic_set(&ts->signal_pending, 1); 864 } 865 866 867 /* Adjust the signal context to rewind out of safe-syscall if we're in it */ 868 static inline void rewind_if_in_safe_syscall(void *puc) 869 { 870 host_sigcontext *uc = (host_sigcontext *)puc; 871 uintptr_t pcreg = host_signal_pc(uc); 872 873 if (pcreg > (uintptr_t)safe_syscall_start 874 && pcreg < (uintptr_t)safe_syscall_end) { 875 host_signal_set_pc(uc, (uintptr_t)safe_syscall_start); 876 } 877 } 878 879 static G_NORETURN 880 void die_from_signal(siginfo_t *info) 881 { 882 char sigbuf[4], codebuf[12]; 883 const char *sig, *code = NULL; 884 885 switch (info->si_signo) { 886 case SIGSEGV: 887 sig = "SEGV"; 888 switch (info->si_code) { 889 case SEGV_MAPERR: 890 code = "MAPERR"; 891 break; 892 case SEGV_ACCERR: 893 code = "ACCERR"; 894 break; 895 } 896 break; 897 case SIGBUS: 898 sig = "BUS"; 899 switch (info->si_code) { 900 case BUS_ADRALN: 901 code = "ADRALN"; 902 break; 903 case BUS_ADRERR: 904 code = "ADRERR"; 905 break; 906 } 907 break; 908 case SIGILL: 909 sig = "ILL"; 910 switch (info->si_code) { 911 case ILL_ILLOPC: 912 code = "ILLOPC"; 913 break; 914 case ILL_ILLOPN: 915 code = "ILLOPN"; 916 break; 917 case ILL_ILLADR: 918 code = "ILLADR"; 919 break; 920 case ILL_PRVOPC: 921 code = "PRVOPC"; 922 break; 923 case ILL_PRVREG: 924 code = "PRVREG"; 925 break; 926 case ILL_COPROC: 927 code = "COPROC"; 928 break; 929 } 930 break; 931 case SIGFPE: 932 sig = "FPE"; 933 switch (info->si_code) { 934 case FPE_INTDIV: 935 code = "INTDIV"; 936 break; 937 case FPE_INTOVF: 938 code = "INTOVF"; 939 break; 940 } 941 break; 942 case SIGTRAP: 943 sig = "TRAP"; 944 break; 945 default: 946 snprintf(sigbuf, sizeof(sigbuf), "%d", info->si_signo); 947 sig = sigbuf; 948 break; 949 } 950 if (code == NULL) { 951 snprintf(codebuf, sizeof(sigbuf), "%d", info->si_code); 952 code = codebuf; 953 } 954 955 error_report("QEMU internal SIG%s {code=%s, addr=%p}", 956 sig, code, info->si_addr); 957 die_with_signal(info->si_signo); 958 } 959 960 static void host_sigsegv_handler(CPUState *cpu, siginfo_t *info, 961 host_sigcontext *uc) 962 { 963 uintptr_t host_addr = (uintptr_t)info->si_addr; 964 /* 965 * Convert forcefully to guest address space: addresses outside 966 * reserved_va are still valid to report via SEGV_MAPERR. 967 */ 968 bool is_valid = h2g_valid(host_addr); 969 abi_ptr guest_addr = h2g_nocheck(host_addr); 970 uintptr_t pc = host_signal_pc(uc); 971 bool is_write = host_signal_write(info, uc); 972 MMUAccessType access_type = adjust_signal_pc(&pc, is_write); 973 bool maperr; 974 975 /* If this was a write to a TB protected page, restart. */ 976 if (is_write 977 && is_valid 978 && info->si_code == SEGV_ACCERR 979 && handle_sigsegv_accerr_write(cpu, host_signal_mask(uc), 980 pc, guest_addr)) { 981 return; 982 } 983 984 /* 985 * If the access was not on behalf of the guest, within the executable 986 * mapping of the generated code buffer, then it is a host bug. 987 */ 988 if (access_type != MMU_INST_FETCH 989 && !in_code_gen_buffer((void *)(pc - tcg_splitwx_diff))) { 990 die_from_signal(info); 991 } 992 993 maperr = true; 994 if (is_valid && info->si_code == SEGV_ACCERR) { 995 /* 996 * With reserved_va, the whole address space is PROT_NONE, 997 * which means that we may get ACCERR when we want MAPERR. 998 */ 999 if (page_get_flags(guest_addr) & PAGE_VALID) { 1000 maperr = false; 1001 } else { 1002 info->si_code = SEGV_MAPERR; 1003 } 1004 } 1005 1006 sigprocmask(SIG_SETMASK, host_signal_mask(uc), NULL); 1007 cpu_loop_exit_sigsegv(cpu, guest_addr, access_type, maperr, pc); 1008 } 1009 1010 static uintptr_t host_sigbus_handler(CPUState *cpu, siginfo_t *info, 1011 host_sigcontext *uc) 1012 { 1013 uintptr_t pc = host_signal_pc(uc); 1014 bool is_write = host_signal_write(info, uc); 1015 MMUAccessType access_type = adjust_signal_pc(&pc, is_write); 1016 1017 /* 1018 * If the access was not on behalf of the guest, within the executable 1019 * mapping of the generated code buffer, then it is a host bug. 1020 */ 1021 if (!in_code_gen_buffer((void *)(pc - tcg_splitwx_diff))) { 1022 die_from_signal(info); 1023 } 1024 1025 if (info->si_code == BUS_ADRALN) { 1026 uintptr_t host_addr = (uintptr_t)info->si_addr; 1027 abi_ptr guest_addr = h2g_nocheck(host_addr); 1028 1029 sigprocmask(SIG_SETMASK, host_signal_mask(uc), NULL); 1030 cpu_loop_exit_sigbus(cpu, guest_addr, access_type, pc); 1031 } 1032 return pc; 1033 } 1034 1035 static void host_signal_handler(int host_sig, siginfo_t *info, void *puc) 1036 { 1037 CPUState *cpu = thread_cpu; 1038 CPUArchState *env = cpu_env(cpu); 1039 TaskState *ts = get_task_state(cpu); 1040 target_siginfo_t tinfo; 1041 host_sigcontext *uc = puc; 1042 struct emulated_sigtable *k; 1043 int guest_sig; 1044 uintptr_t pc = 0; 1045 bool sync_sig = false; 1046 void *sigmask; 1047 1048 if (host_sig == host_interrupt_signal) { 1049 ts->signal_pending = 1; 1050 cpu_exit(thread_cpu); 1051 return; 1052 } 1053 1054 /* 1055 * Non-spoofed SIGSEGV and SIGBUS are synchronous, and need special 1056 * handling wrt signal blocking and unwinding. Non-spoofed SIGILL, 1057 * SIGFPE, SIGTRAP are always host bugs. 1058 */ 1059 if (info->si_code > 0) { 1060 switch (host_sig) { 1061 case SIGSEGV: 1062 /* Only returns on handle_sigsegv_accerr_write success. */ 1063 host_sigsegv_handler(cpu, info, uc); 1064 return; 1065 case SIGBUS: 1066 pc = host_sigbus_handler(cpu, info, uc); 1067 sync_sig = true; 1068 break; 1069 case SIGILL: 1070 case SIGFPE: 1071 case SIGTRAP: 1072 die_from_signal(info); 1073 } 1074 } 1075 1076 /* get target signal number */ 1077 guest_sig = host_to_target_signal(host_sig); 1078 if (guest_sig < 1 || guest_sig > TARGET_NSIG) { 1079 return; 1080 } 1081 trace_user_host_signal(env, host_sig, guest_sig); 1082 1083 host_to_target_siginfo_noswap(&tinfo, info); 1084 k = &ts->sigtab[guest_sig - 1]; 1085 k->info = tinfo; 1086 k->pending = guest_sig; 1087 ts->signal_pending = 1; 1088 1089 /* 1090 * For synchronous signals, unwind the cpu state to the faulting 1091 * insn and then exit back to the main loop so that the signal 1092 * is delivered immediately. 1093 */ 1094 if (sync_sig) { 1095 cpu->exception_index = EXCP_INTERRUPT; 1096 cpu_loop_exit_restore(cpu, pc); 1097 } 1098 1099 rewind_if_in_safe_syscall(puc); 1100 1101 /* 1102 * Block host signals until target signal handler entered. We 1103 * can't block SIGSEGV or SIGBUS while we're executing guest 1104 * code in case the guest code provokes one in the window between 1105 * now and it getting out to the main loop. Signals will be 1106 * unblocked again in process_pending_signals(). 1107 * 1108 * WARNING: we cannot use sigfillset() here because the sigmask 1109 * field is a kernel sigset_t, which is much smaller than the 1110 * libc sigset_t which sigfillset() operates on. Using sigfillset() 1111 * would write 0xff bytes off the end of the structure and trash 1112 * data on the struct. 1113 */ 1114 sigmask = host_signal_mask(uc); 1115 memset(sigmask, 0xff, SIGSET_T_SIZE); 1116 sigdelset(sigmask, SIGSEGV); 1117 sigdelset(sigmask, SIGBUS); 1118 1119 /* interrupt the virtual CPU as soon as possible */ 1120 cpu_exit(thread_cpu); 1121 } 1122 1123 /* do_sigaltstack() returns target values and errnos. */ 1124 /* compare linux/kernel/signal.c:do_sigaltstack() */ 1125 abi_long do_sigaltstack(abi_ulong uss_addr, abi_ulong uoss_addr, 1126 CPUArchState *env) 1127 { 1128 target_stack_t oss, *uoss = NULL; 1129 abi_long ret = -TARGET_EFAULT; 1130 1131 if (uoss_addr) { 1132 /* Verify writability now, but do not alter user memory yet. */ 1133 if (!lock_user_struct(VERIFY_WRITE, uoss, uoss_addr, 0)) { 1134 goto out; 1135 } 1136 target_save_altstack(&oss, env); 1137 } 1138 1139 if (uss_addr) { 1140 target_stack_t *uss; 1141 1142 if (!lock_user_struct(VERIFY_READ, uss, uss_addr, 1)) { 1143 goto out; 1144 } 1145 ret = target_restore_altstack(uss, env); 1146 if (ret) { 1147 goto out; 1148 } 1149 } 1150 1151 if (uoss_addr) { 1152 memcpy(uoss, &oss, sizeof(oss)); 1153 unlock_user_struct(uoss, uoss_addr, 1); 1154 uoss = NULL; 1155 } 1156 ret = 0; 1157 1158 out: 1159 if (uoss) { 1160 unlock_user_struct(uoss, uoss_addr, 0); 1161 } 1162 return ret; 1163 } 1164 1165 /* do_sigaction() return target values and host errnos */ 1166 int do_sigaction(int sig, const struct target_sigaction *act, 1167 struct target_sigaction *oact, abi_ulong ka_restorer) 1168 { 1169 struct target_sigaction *k; 1170 int host_sig; 1171 int ret = 0; 1172 1173 trace_signal_do_sigaction_guest(sig, TARGET_NSIG); 1174 1175 if (sig < 1 || sig > TARGET_NSIG) { 1176 return -TARGET_EINVAL; 1177 } 1178 1179 if (act && (sig == TARGET_SIGKILL || sig == TARGET_SIGSTOP)) { 1180 return -TARGET_EINVAL; 1181 } 1182 1183 if (block_signals()) { 1184 return -QEMU_ERESTARTSYS; 1185 } 1186 1187 k = &sigact_table[sig - 1]; 1188 if (oact) { 1189 __put_user(k->_sa_handler, &oact->_sa_handler); 1190 __put_user(k->sa_flags, &oact->sa_flags); 1191 #ifdef TARGET_ARCH_HAS_SA_RESTORER 1192 __put_user(k->sa_restorer, &oact->sa_restorer); 1193 #endif 1194 /* Not swapped. */ 1195 oact->sa_mask = k->sa_mask; 1196 } 1197 if (act) { 1198 __get_user(k->_sa_handler, &act->_sa_handler); 1199 __get_user(k->sa_flags, &act->sa_flags); 1200 #ifdef TARGET_ARCH_HAS_SA_RESTORER 1201 __get_user(k->sa_restorer, &act->sa_restorer); 1202 #endif 1203 #ifdef TARGET_ARCH_HAS_KA_RESTORER 1204 k->ka_restorer = ka_restorer; 1205 #endif 1206 /* To be swapped in target_to_host_sigset. */ 1207 k->sa_mask = act->sa_mask; 1208 1209 /* we update the host linux signal state */ 1210 host_sig = target_to_host_signal(sig); 1211 trace_signal_do_sigaction_host(host_sig, TARGET_NSIG); 1212 if (host_sig > SIGRTMAX) { 1213 /* we don't have enough host signals to map all target signals */ 1214 qemu_log_mask(LOG_UNIMP, "Unsupported target signal #%d, ignored\n", 1215 sig); 1216 /* 1217 * we don't return an error here because some programs try to 1218 * register an handler for all possible rt signals even if they 1219 * don't need it. 1220 * An error here can abort them whereas there can be no problem 1221 * to not have the signal available later. 1222 * This is the case for golang, 1223 * See https://github.com/golang/go/issues/33746 1224 * So we silently ignore the error. 1225 */ 1226 return 0; 1227 } 1228 if (host_sig != SIGSEGV && host_sig != SIGBUS) { 1229 struct sigaction act1; 1230 1231 sigfillset(&act1.sa_mask); 1232 act1.sa_flags = SA_SIGINFO; 1233 if (k->_sa_handler == TARGET_SIG_IGN) { 1234 /* 1235 * It is important to update the host kernel signal ignore 1236 * state to avoid getting unexpected interrupted syscalls. 1237 */ 1238 act1.sa_sigaction = (void *)SIG_IGN; 1239 } else if (k->_sa_handler == TARGET_SIG_DFL) { 1240 if (core_dump_signal(sig)) { 1241 act1.sa_sigaction = host_signal_handler; 1242 } else { 1243 act1.sa_sigaction = (void *)SIG_DFL; 1244 } 1245 } else { 1246 act1.sa_sigaction = host_signal_handler; 1247 if (k->sa_flags & TARGET_SA_RESTART) { 1248 act1.sa_flags |= SA_RESTART; 1249 } 1250 } 1251 ret = sigaction(host_sig, &act1, NULL); 1252 } 1253 } 1254 return ret; 1255 } 1256 1257 static void handle_pending_signal(CPUArchState *cpu_env, int sig, 1258 struct emulated_sigtable *k) 1259 { 1260 CPUState *cpu = env_cpu(cpu_env); 1261 abi_ulong handler; 1262 sigset_t set; 1263 target_siginfo_t unswapped; 1264 target_sigset_t target_old_set; 1265 struct target_sigaction *sa; 1266 TaskState *ts = get_task_state(cpu); 1267 1268 trace_user_handle_signal(cpu_env, sig); 1269 /* dequeue signal */ 1270 k->pending = 0; 1271 1272 /* 1273 * Writes out siginfo values byteswapped, accordingly to the target. 1274 * It also cleans the si_type from si_code making it correct for 1275 * the target. We must hold on to the original unswapped copy for 1276 * strace below, because si_type is still required there. 1277 */ 1278 if (unlikely(qemu_loglevel_mask(LOG_STRACE))) { 1279 unswapped = k->info; 1280 } 1281 tswap_siginfo(&k->info, &k->info); 1282 1283 sig = gdb_handlesig(cpu, sig, NULL, &k->info, sizeof(k->info)); 1284 if (!sig) { 1285 sa = NULL; 1286 handler = TARGET_SIG_IGN; 1287 } else { 1288 sa = &sigact_table[sig - 1]; 1289 handler = sa->_sa_handler; 1290 } 1291 1292 if (unlikely(qemu_loglevel_mask(LOG_STRACE))) { 1293 print_taken_signal(sig, &unswapped); 1294 } 1295 1296 if (handler == TARGET_SIG_DFL) { 1297 /* default handler : ignore some signal. The other are job control or fatal */ 1298 if (sig == TARGET_SIGTSTP || sig == TARGET_SIGTTIN || sig == TARGET_SIGTTOU) { 1299 kill(getpid(),SIGSTOP); 1300 } else if (sig != TARGET_SIGCHLD && 1301 sig != TARGET_SIGURG && 1302 sig != TARGET_SIGWINCH && 1303 sig != TARGET_SIGCONT) { 1304 dump_core_and_abort(cpu_env, sig); 1305 } 1306 } else if (handler == TARGET_SIG_IGN) { 1307 /* ignore sig */ 1308 } else if (handler == TARGET_SIG_ERR) { 1309 dump_core_and_abort(cpu_env, sig); 1310 } else { 1311 /* compute the blocked signals during the handler execution */ 1312 sigset_t *blocked_set; 1313 1314 target_to_host_sigset(&set, &sa->sa_mask); 1315 /* SA_NODEFER indicates that the current signal should not be 1316 blocked during the handler */ 1317 if (!(sa->sa_flags & TARGET_SA_NODEFER)) 1318 sigaddset(&set, target_to_host_signal(sig)); 1319 1320 /* save the previous blocked signal state to restore it at the 1321 end of the signal execution (see do_sigreturn) */ 1322 host_to_target_sigset_internal(&target_old_set, &ts->signal_mask); 1323 1324 /* block signals in the handler */ 1325 blocked_set = ts->in_sigsuspend ? 1326 &ts->sigsuspend_mask : &ts->signal_mask; 1327 sigorset(&ts->signal_mask, blocked_set, &set); 1328 ts->in_sigsuspend = 0; 1329 1330 /* if the CPU is in VM86 mode, we restore the 32 bit values */ 1331 #if defined(TARGET_I386) && !defined(TARGET_X86_64) 1332 { 1333 CPUX86State *env = cpu_env; 1334 if (env->eflags & VM_MASK) 1335 save_v86_state(env); 1336 } 1337 #endif 1338 /* prepare the stack frame of the virtual CPU */ 1339 #if defined(TARGET_ARCH_HAS_SETUP_FRAME) 1340 if (sa->sa_flags & TARGET_SA_SIGINFO) { 1341 setup_rt_frame(sig, sa, &k->info, &target_old_set, cpu_env); 1342 } else { 1343 setup_frame(sig, sa, &target_old_set, cpu_env); 1344 } 1345 #else 1346 /* These targets do not have traditional signals. */ 1347 setup_rt_frame(sig, sa, &k->info, &target_old_set, cpu_env); 1348 #endif 1349 if (sa->sa_flags & TARGET_SA_RESETHAND) { 1350 sa->_sa_handler = TARGET_SIG_DFL; 1351 } 1352 } 1353 } 1354 1355 void process_pending_signals(CPUArchState *cpu_env) 1356 { 1357 CPUState *cpu = env_cpu(cpu_env); 1358 int sig; 1359 TaskState *ts = get_task_state(cpu); 1360 sigset_t set; 1361 sigset_t *blocked_set; 1362 1363 while (qatomic_read(&ts->signal_pending)) { 1364 sigfillset(&set); 1365 sigprocmask(SIG_SETMASK, &set, 0); 1366 1367 restart_scan: 1368 sig = ts->sync_signal.pending; 1369 if (sig) { 1370 /* Synchronous signals are forced, 1371 * see force_sig_info() and callers in Linux 1372 * Note that not all of our queue_signal() calls in QEMU correspond 1373 * to force_sig_info() calls in Linux (some are send_sig_info()). 1374 * However it seems like a kernel bug to me to allow the process 1375 * to block a synchronous signal since it could then just end up 1376 * looping round and round indefinitely. 1377 */ 1378 if (sigismember(&ts->signal_mask, target_to_host_signal_table[sig]) 1379 || sigact_table[sig - 1]._sa_handler == TARGET_SIG_IGN) { 1380 sigdelset(&ts->signal_mask, target_to_host_signal_table[sig]); 1381 sigact_table[sig - 1]._sa_handler = TARGET_SIG_DFL; 1382 } 1383 1384 handle_pending_signal(cpu_env, sig, &ts->sync_signal); 1385 } 1386 1387 for (sig = 1; sig <= TARGET_NSIG; sig++) { 1388 blocked_set = ts->in_sigsuspend ? 1389 &ts->sigsuspend_mask : &ts->signal_mask; 1390 1391 if (ts->sigtab[sig - 1].pending && 1392 (!sigismember(blocked_set, 1393 target_to_host_signal_table[sig]))) { 1394 handle_pending_signal(cpu_env, sig, &ts->sigtab[sig - 1]); 1395 /* Restart scan from the beginning, as handle_pending_signal 1396 * might have resulted in a new synchronous signal (eg SIGSEGV). 1397 */ 1398 goto restart_scan; 1399 } 1400 } 1401 1402 /* if no signal is pending, unblock signals and recheck (the act 1403 * of unblocking might cause us to take another host signal which 1404 * will set signal_pending again). 1405 */ 1406 qatomic_set(&ts->signal_pending, 0); 1407 ts->in_sigsuspend = 0; 1408 set = ts->signal_mask; 1409 sigdelset(&set, SIGSEGV); 1410 sigdelset(&set, SIGBUS); 1411 sigprocmask(SIG_SETMASK, &set, 0); 1412 } 1413 ts->in_sigsuspend = 0; 1414 } 1415 1416 int process_sigsuspend_mask(sigset_t **pset, target_ulong sigset, 1417 target_ulong sigsize) 1418 { 1419 TaskState *ts = get_task_state(thread_cpu); 1420 sigset_t *host_set = &ts->sigsuspend_mask; 1421 target_sigset_t *target_sigset; 1422 1423 if (sigsize != sizeof(*target_sigset)) { 1424 /* Like the kernel, we enforce correct size sigsets */ 1425 return -TARGET_EINVAL; 1426 } 1427 1428 target_sigset = lock_user(VERIFY_READ, sigset, sigsize, 1); 1429 if (!target_sigset) { 1430 return -TARGET_EFAULT; 1431 } 1432 target_to_host_sigset(host_set, target_sigset); 1433 unlock_user(target_sigset, sigset, 0); 1434 1435 *pset = host_set; 1436 return 0; 1437 } 1438