| 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 | abi_ulong vdso_sigreturn_region_start; |
| 54 | abi_ulong vdso_sigreturn_region_end; |
| 55 | |
| 56 | /* |
| 57 | * System includes define _NSIG as SIGRTMAX + 1, but qemu (like the kernel) |
| 58 | * defines TARGET_NSIG as TARGET_SIGRTMAX and the first signal is 1. |
| 59 | * Signal number 0 is reserved for use as kill(pid, 0), to test whether |
| 60 | * a process exists without sending it a signal. |
| 61 | */ |
| 62 | #ifdef __SIGRTMAX |
| 63 | QEMU_BUILD_BUG_ON(__SIGRTMAX + 1 != _NSIG); |
| 64 | #endif |
| 65 | static uint8_t host_to_target_signal_table[_NSIG] = { |
| 66 | #define MAKE_SIG_ENTRY(sig) [sig] = TARGET_##sig, |
| 67 | MAKE_SIGNAL_LIST |
| 68 | #undef MAKE_SIG_ENTRY |
| 69 | }; |
| 70 | |
| 71 | static uint8_t target_to_host_signal_table[TARGET_NSIG + 1]; |
| 72 | |
| 73 | /* valid sig is between 1 and _NSIG - 1 */ |
| 74 | int host_to_target_signal(int sig) |
| 75 | { |
| 76 | if (sig < 1) { |
| 77 | return sig; |
| 78 | } |
| 79 | if (sig >= _NSIG) { |
| 80 | return TARGET_NSIG + 1; |
| 81 | } |
| 82 | return host_to_target_signal_table[sig]; |
| 83 | } |
| 84 | |
| 85 | /* valid sig is between 1 and TARGET_NSIG */ |
| 86 | int target_to_host_signal(int sig) |
| 87 | { |
| 88 | if (sig < 1) { |
| 89 | return sig; |
| 90 | } |
| 91 | if (sig > TARGET_NSIG) { |
| 92 | return _NSIG; |
| 93 | } |
| 94 | return target_to_host_signal_table[sig]; |
| 95 | } |
| 96 | |
| 97 | static inline void target_sigaddset(target_sigset_t *set, int signum) |
| 98 | { |
| 99 | signum--; |
| 100 | abi_ulong mask = (abi_ulong)1 << (signum % TARGET_NSIG_BPW); |
| 101 | set->sig[signum / TARGET_NSIG_BPW] |= mask; |
| 102 | } |
| 103 | |
| 104 | static inline int target_sigismember(const target_sigset_t *set, int signum) |
| 105 | { |
| 106 | signum--; |
| 107 | abi_ulong mask = (abi_ulong)1 << (signum % TARGET_NSIG_BPW); |
| 108 | return ((set->sig[signum / TARGET_NSIG_BPW] & mask) != 0); |
| 109 | } |
| 110 | |
| 111 | void host_to_target_sigset_internal(target_sigset_t *d, |
| 112 | const sigset_t *s) |
| 113 | { |
| 114 | int host_sig, target_sig; |
| 115 | target_sigemptyset(d); |
| 116 | for (host_sig = 1; host_sig < _NSIG; host_sig++) { |
| 117 | target_sig = host_to_target_signal(host_sig); |
| 118 | if (target_sig < 1 || target_sig > TARGET_NSIG) { |
| 119 | continue; |
| 120 | } |
| 121 | if (sigismember(s, host_sig)) { |
| 122 | target_sigaddset(d, target_sig); |
| 123 | } |
| 124 | } |
| 125 | } |
| 126 | |
| 127 | void host_to_target_sigset(target_sigset_t *d, const sigset_t *s) |
| 128 | { |
| 129 | target_sigset_t d1; |
| 130 | int i; |
| 131 | |
| 132 | host_to_target_sigset_internal(&d1, s); |
| 133 | for(i = 0;i < TARGET_NSIG_WORDS; i++) |
| 134 | d->sig[i] = tswapal(d1.sig[i]); |
| 135 | } |
| 136 | |
| 137 | void target_to_host_sigset_internal(sigset_t *d, |
| 138 | const target_sigset_t *s) |
| 139 | { |
| 140 | int host_sig, target_sig; |
| 141 | sigemptyset(d); |
| 142 | for (target_sig = 1; target_sig <= TARGET_NSIG; target_sig++) { |
| 143 | host_sig = target_to_host_signal(target_sig); |
| 144 | if (host_sig < 1 || host_sig >= _NSIG) { |
| 145 | continue; |
| 146 | } |
| 147 | if (target_sigismember(s, target_sig)) { |
| 148 | sigaddset(d, host_sig); |
| 149 | } |
| 150 | } |
| 151 | } |
| 152 | |
| 153 | void target_to_host_sigset(sigset_t *d, const target_sigset_t *s) |
| 154 | { |
| 155 | target_sigset_t s1; |
| 156 | int i; |
| 157 | |
| 158 | for(i = 0;i < TARGET_NSIG_WORDS; i++) |
| 159 | s1.sig[i] = tswapal(s->sig[i]); |
| 160 | target_to_host_sigset_internal(d, &s1); |
| 161 | } |
| 162 | |
| 163 | void host_to_target_old_sigset(abi_ulong *old_sigset, |
| 164 | const sigset_t *sigset) |
| 165 | { |
| 166 | target_sigset_t d; |
| 167 | host_to_target_sigset(&d, sigset); |
| 168 | *old_sigset = d.sig[0]; |
| 169 | } |
| 170 | |
| 171 | void target_to_host_old_sigset(sigset_t *sigset, |
| 172 | const abi_ulong *old_sigset) |
| 173 | { |
| 174 | target_sigset_t d; |
| 175 | int i; |
| 176 | |
| 177 | d.sig[0] = *old_sigset; |
| 178 | for(i = 1;i < TARGET_NSIG_WORDS; i++) |
| 179 | d.sig[i] = 0; |
| 180 | target_to_host_sigset(sigset, &d); |
| 181 | } |
| 182 | |
| 183 | int block_signals(void) |
| 184 | { |
| 185 | TaskState *ts = get_task_state(thread_cpu); |
| 186 | sigset_t set; |
| 187 | |
| 188 | /* It's OK to block everything including SIGSEGV, because we won't |
| 189 | * run any further guest code before unblocking signals in |
| 190 | * process_pending_signals(). |
| 191 | */ |
| 192 | sigfillset(&set); |
| 193 | sigprocmask(SIG_SETMASK, &set, 0); |
| 194 | |
| 195 | return qatomic_xchg(&ts->signal_pending, 1); |
| 196 | } |
| 197 | |
| 198 | /* Wrapper for sigprocmask function |
| 199 | * Emulates a sigprocmask in a safe way for the guest. Note that set and oldset |
| 200 | * are host signal set, not guest ones. Returns -QEMU_ERESTARTSYS if |
| 201 | * a signal was already pending and the syscall must be restarted, or |
| 202 | * 0 on success. |
| 203 | * If set is NULL, this is guaranteed not to fail. |
| 204 | */ |
| 205 | int do_sigprocmask(int how, const sigset_t *set, sigset_t *oldset) |
| 206 | { |
| 207 | TaskState *ts = get_task_state(thread_cpu); |
| 208 | |
| 209 | if (oldset) { |
| 210 | *oldset = ts->signal_mask; |
| 211 | } |
| 212 | |
| 213 | if (set) { |
| 214 | int i; |
| 215 | |
| 216 | if (block_signals()) { |
| 217 | return -QEMU_ERESTARTSYS; |
| 218 | } |
| 219 | |
| 220 | switch (how) { |
| 221 | case SIG_BLOCK: |
| 222 | sigorset(&ts->signal_mask, &ts->signal_mask, set); |
| 223 | break; |
| 224 | case SIG_UNBLOCK: |
| 225 | for (i = 1; i <= NSIG; ++i) { |
| 226 | if (sigismember(set, i)) { |
| 227 | sigdelset(&ts->signal_mask, i); |
| 228 | } |
| 229 | } |
| 230 | break; |
| 231 | case SIG_SETMASK: |
| 232 | ts->signal_mask = *set; |
| 233 | break; |
| 234 | default: |
| 235 | g_assert_not_reached(); |
| 236 | } |
| 237 | |
| 238 | /* Silently ignore attempts to change blocking status of KILL or STOP */ |
| 239 | sigdelset(&ts->signal_mask, SIGKILL); |
| 240 | sigdelset(&ts->signal_mask, SIGSTOP); |
| 241 | } |
| 242 | return 0; |
| 243 | } |
| 244 | |
| 245 | /* Just set the guest's signal mask to the specified value; the |
| 246 | * caller is assumed to have called block_signals() already. |
| 247 | */ |
| 248 | void set_sigmask(const sigset_t *set) |
| 249 | { |
| 250 | TaskState *ts = get_task_state(thread_cpu); |
| 251 | |
| 252 | ts->signal_mask = *set; |
| 253 | } |
| 254 | |
| 255 | /* sigaltstack management */ |
| 256 | |
| 257 | int on_sig_stack(unsigned long sp) |
| 258 | { |
| 259 | TaskState *ts = get_task_state(thread_cpu); |
| 260 | |
| 261 | return (sp - ts->sigaltstack_used.ss_sp |
| 262 | < ts->sigaltstack_used.ss_size); |
| 263 | } |
| 264 | |
| 265 | int sas_ss_flags(unsigned long sp) |
| 266 | { |
| 267 | TaskState *ts = get_task_state(thread_cpu); |
| 268 | |
| 269 | return (ts->sigaltstack_used.ss_size == 0 ? SS_DISABLE |
| 270 | : on_sig_stack(sp) ? SS_ONSTACK : 0); |
| 271 | } |
| 272 | |
| 273 | abi_ulong target_sigsp(abi_ulong sp, struct target_sigaction *ka) |
| 274 | { |
| 275 | /* |
| 276 | * This is the X/Open sanctioned signal stack switching. |
| 277 | */ |
| 278 | TaskState *ts = get_task_state(thread_cpu); |
| 279 | |
| 280 | if ((ka->sa_flags & TARGET_SA_ONSTACK) && !sas_ss_flags(sp)) { |
| 281 | return ts->sigaltstack_used.ss_sp + ts->sigaltstack_used.ss_size; |
| 282 | } |
| 283 | return sp; |
| 284 | } |
| 285 | |
| 286 | void target_save_altstack(target_stack_t *uss, CPUArchState *env) |
| 287 | { |
| 288 | TaskState *ts = get_task_state(thread_cpu); |
| 289 | |
| 290 | __put_user(ts->sigaltstack_used.ss_sp, &uss->ss_sp); |
| 291 | __put_user(sas_ss_flags(get_sp_from_cpustate(env)), &uss->ss_flags); |
| 292 | __put_user(ts->sigaltstack_used.ss_size, &uss->ss_size); |
| 293 | } |
| 294 | |
| 295 | abi_long target_restore_altstack(target_stack_t *uss, CPUArchState *env) |
| 296 | { |
| 297 | TaskState *ts = get_task_state(thread_cpu); |
| 298 | size_t minstacksize = TARGET_MINSIGSTKSZ; |
| 299 | target_stack_t ss; |
| 300 | |
| 301 | #if defined(TARGET_PPC64) |
| 302 | /* ELF V2 for PPC64 has a 4K minimum stack size for signal handlers */ |
| 303 | struct image_info *image = ts->info; |
| 304 | if (get_ppc64_abi(image) > 1) { |
| 305 | minstacksize = 4096; |
| 306 | } |
| 307 | #endif |
| 308 | |
| 309 | __get_user(ss.ss_sp, &uss->ss_sp); |
| 310 | __get_user(ss.ss_size, &uss->ss_size); |
| 311 | __get_user(ss.ss_flags, &uss->ss_flags); |
| 312 | |
| 313 | if (on_sig_stack(get_sp_from_cpustate(env))) { |
| 314 | return -TARGET_EPERM; |
| 315 | } |
| 316 | |
| 317 | switch (ss.ss_flags) { |
| 318 | default: |
| 319 | return -TARGET_EINVAL; |
| 320 | |
| 321 | case TARGET_SS_DISABLE: |
| 322 | ss.ss_size = 0; |
| 323 | ss.ss_sp = 0; |
| 324 | break; |
| 325 | |
| 326 | case TARGET_SS_ONSTACK: |
| 327 | case 0: |
| 328 | if (ss.ss_size < minstacksize) { |
| 329 | return -TARGET_ENOMEM; |
| 330 | } |
| 331 | break; |
| 332 | } |
| 333 | |
| 334 | ts->sigaltstack_used.ss_sp = ss.ss_sp; |
| 335 | ts->sigaltstack_used.ss_size = ss.ss_size; |
| 336 | return 0; |
| 337 | } |
| 338 | |
| 339 | /* siginfo conversion */ |
| 340 | |
| 341 | static inline void host_to_target_siginfo_noswap(target_siginfo_t *tinfo, |
| 342 | const siginfo_t *info) |
| 343 | { |
| 344 | int sig = host_to_target_signal(info->si_signo); |
| 345 | int si_code = info->si_code; |
| 346 | int si_type; |
| 347 | tinfo->si_signo = sig; |
| 348 | tinfo->si_errno = 0; |
| 349 | tinfo->si_code = info->si_code; |
| 350 | |
| 351 | /* This memset serves two purposes: |
| 352 | * (1) ensure we don't leak random junk to the guest later |
| 353 | * (2) placate false positives from gcc about fields |
| 354 | * being used uninitialized if it chooses to inline both this |
| 355 | * function and tswap_siginfo() into host_to_target_siginfo(). |
| 356 | */ |
| 357 | memset(tinfo->_sifields._pad, 0, sizeof(tinfo->_sifields._pad)); |
| 358 | |
| 359 | /* This is awkward, because we have to use a combination of |
| 360 | * the si_code and si_signo to figure out which of the union's |
| 361 | * members are valid. (Within the host kernel it is always possible |
| 362 | * to tell, but the kernel carefully avoids giving userspace the |
| 363 | * high 16 bits of si_code, so we don't have the information to |
| 364 | * do this the easy way...) We therefore make our best guess, |
| 365 | * bearing in mind that a guest can spoof most of the si_codes |
| 366 | * via rt_sigqueueinfo() if it likes. |
| 367 | * |
| 368 | * Once we have made our guess, we record it in the top 16 bits of |
| 369 | * the si_code, so that tswap_siginfo() later can use it. |
| 370 | * tswap_siginfo() will strip these top bits out before writing |
| 371 | * si_code to the guest (sign-extending the lower bits). |
| 372 | */ |
| 373 | |
| 374 | switch (si_code) { |
| 375 | case SI_USER: |
| 376 | case SI_TKILL: |
| 377 | case SI_KERNEL: |
| 378 | /* Sent via kill(), tkill() or tgkill(), or direct from the kernel. |
| 379 | * These are the only unspoofable si_code values. |
| 380 | */ |
| 381 | tinfo->_sifields._kill._pid = info->si_pid; |
| 382 | tinfo->_sifields._kill._uid = info->si_uid; |
| 383 | si_type = QEMU_SI_KILL; |
| 384 | break; |
| 385 | default: |
| 386 | /* Everything else is spoofable. Make best guess based on signal */ |
| 387 | switch (sig) { |
| 388 | case TARGET_SIGCHLD: |
| 389 | tinfo->_sifields._sigchld._pid = info->si_pid; |
| 390 | tinfo->_sifields._sigchld._uid = info->si_uid; |
| 391 | if (si_code == CLD_EXITED) |
| 392 | tinfo->_sifields._sigchld._status = info->si_status; |
| 393 | else |
| 394 | tinfo->_sifields._sigchld._status |
| 395 | = host_to_target_signal(info->si_status & 0x7f) |
| 396 | | (info->si_status & ~0x7f); |
| 397 | tinfo->_sifields._sigchld._utime = info->si_utime; |
| 398 | tinfo->_sifields._sigchld._stime = info->si_stime; |
| 399 | si_type = QEMU_SI_CHLD; |
| 400 | break; |
| 401 | case TARGET_SIGIO: |
| 402 | tinfo->_sifields._sigpoll._band = info->si_band; |
| 403 | tinfo->_sifields._sigpoll._fd = info->si_fd; |
| 404 | si_type = QEMU_SI_POLL; |
| 405 | break; |
| 406 | default: |
| 407 | /* Assume a sigqueue()/mq_notify()/rt_sigqueueinfo() source. */ |
| 408 | tinfo->_sifields._rt._pid = info->si_pid; |
| 409 | tinfo->_sifields._rt._uid = info->si_uid; |
| 410 | /* XXX: potential problem if 64 bit */ |
| 411 | tinfo->_sifields._rt._sigval.sival_ptr |
| 412 | = (abi_ulong)(unsigned long)info->si_value.sival_ptr; |
| 413 | si_type = QEMU_SI_RT; |
| 414 | break; |
| 415 | } |
| 416 | break; |
| 417 | } |
| 418 | |
| 419 | tinfo->si_code = deposit32(si_code, 16, 16, si_type); |
| 420 | } |
| 421 | |
| 422 | static void tswap_siginfo(target_siginfo_t *tinfo, |
| 423 | const target_siginfo_t *info) |
| 424 | { |
| 425 | int si_type = extract32(info->si_code, 16, 16); |
| 426 | int si_code = sextract32(info->si_code, 0, 16); |
| 427 | |
| 428 | __put_user(info->si_signo, &tinfo->si_signo); |
| 429 | __put_user(info->si_errno, &tinfo->si_errno); |
| 430 | __put_user(si_code, &tinfo->si_code); |
| 431 | |
| 432 | /* We can use our internal marker of which fields in the structure |
| 433 | * are valid, rather than duplicating the guesswork of |
| 434 | * host_to_target_siginfo_noswap() here. |
| 435 | */ |
| 436 | switch (si_type) { |
| 437 | case QEMU_SI_KILL: |
| 438 | __put_user(info->_sifields._kill._pid, &tinfo->_sifields._kill._pid); |
| 439 | __put_user(info->_sifields._kill._uid, &tinfo->_sifields._kill._uid); |
| 440 | break; |
| 441 | case QEMU_SI_TIMER: |
| 442 | __put_user(info->_sifields._timer._timer1, |
| 443 | &tinfo->_sifields._timer._timer1); |
| 444 | __put_user(info->_sifields._timer._timer2, |
| 445 | &tinfo->_sifields._timer._timer2); |
| 446 | break; |
| 447 | case QEMU_SI_POLL: |
| 448 | __put_user(info->_sifields._sigpoll._band, |
| 449 | &tinfo->_sifields._sigpoll._band); |
| 450 | __put_user(info->_sifields._sigpoll._fd, |
| 451 | &tinfo->_sifields._sigpoll._fd); |
| 452 | break; |
| 453 | case QEMU_SI_FAULT: |
| 454 | __put_user(info->_sifields._sigfault._addr, |
| 455 | &tinfo->_sifields._sigfault._addr); |
| 456 | break; |
| 457 | case QEMU_SI_CHLD: |
| 458 | __put_user(info->_sifields._sigchld._pid, |
| 459 | &tinfo->_sifields._sigchld._pid); |
| 460 | __put_user(info->_sifields._sigchld._uid, |
| 461 | &tinfo->_sifields._sigchld._uid); |
| 462 | __put_user(info->_sifields._sigchld._status, |
| 463 | &tinfo->_sifields._sigchld._status); |
| 464 | __put_user(info->_sifields._sigchld._utime, |
| 465 | &tinfo->_sifields._sigchld._utime); |
| 466 | __put_user(info->_sifields._sigchld._stime, |
| 467 | &tinfo->_sifields._sigchld._stime); |
| 468 | break; |
| 469 | case QEMU_SI_RT: |
| 470 | __put_user(info->_sifields._rt._pid, &tinfo->_sifields._rt._pid); |
| 471 | __put_user(info->_sifields._rt._uid, &tinfo->_sifields._rt._uid); |
| 472 | __put_user(info->_sifields._rt._sigval.sival_ptr, |
| 473 | &tinfo->_sifields._rt._sigval.sival_ptr); |
| 474 | break; |
| 475 | default: |
| 476 | g_assert_not_reached(); |
| 477 | } |
| 478 | } |
| 479 | |
| 480 | void host_to_target_siginfo(target_siginfo_t *tinfo, const siginfo_t *info) |
| 481 | { |
| 482 | target_siginfo_t tgt_tmp; |
| 483 | host_to_target_siginfo_noswap(&tgt_tmp, info); |
| 484 | tswap_siginfo(tinfo, &tgt_tmp); |
| 485 | } |
| 486 | |
| 487 | /* XXX: we support only POSIX RT signals are used. */ |
| 488 | /* XXX: find a solution for 64 bit (additional malloced data is needed) */ |
| 489 | void target_to_host_siginfo(siginfo_t *info, const target_siginfo_t *tinfo) |
| 490 | { |
| 491 | /* This conversion is used only for the rt_sigqueueinfo syscall, |
| 492 | * and so we know that the _rt fields are the valid ones. |
| 493 | */ |
| 494 | abi_ulong sival_ptr; |
| 495 | |
| 496 | __get_user(info->si_signo, &tinfo->si_signo); |
| 497 | __get_user(info->si_errno, &tinfo->si_errno); |
| 498 | __get_user(info->si_code, &tinfo->si_code); |
| 499 | __get_user(info->si_pid, &tinfo->_sifields._rt._pid); |
| 500 | __get_user(info->si_uid, &tinfo->_sifields._rt._uid); |
| 501 | __get_user(sival_ptr, &tinfo->_sifields._rt._sigval.sival_ptr); |
| 502 | info->si_value.sival_ptr = (void *)(long)sival_ptr; |
| 503 | } |
| 504 | |
| 505 | /* returns 1 if given signal should dump core if not handled */ |
| 506 | static int core_dump_signal(int sig) |
| 507 | { |
| 508 | switch (sig) { |
| 509 | case TARGET_SIGABRT: |
| 510 | case TARGET_SIGFPE: |
| 511 | case TARGET_SIGILL: |
| 512 | case TARGET_SIGQUIT: |
| 513 | case TARGET_SIGSEGV: |
| 514 | case TARGET_SIGTRAP: |
| 515 | case TARGET_SIGBUS: |
| 516 | return (1); |
| 517 | default: |
| 518 | return (0); |
| 519 | } |
| 520 | } |
| 521 | |
| 522 | int host_interrupt_signal; |
| 523 | |
| 524 | static void signal_table_init(const char *rtsig_map) |
| 525 | { |
| 526 | int hsig, tsig, count; |
| 527 | |
| 528 | if (rtsig_map) { |
| 529 | /* |
| 530 | * Map host RT signals to target RT signals according to the |
| 531 | * user-provided specification. |
| 532 | */ |
| 533 | const char *s = rtsig_map; |
| 534 | |
| 535 | while (true) { |
| 536 | int i; |
| 537 | |
| 538 | if (qemu_strtoi(s, &s, 10, &tsig) || *s++ != ' ') { |
| 539 | fprintf(stderr, "Malformed target signal in QEMU_RTSIG_MAP\n"); |
| 540 | exit(EXIT_FAILURE); |
| 541 | } |
| 542 | if (qemu_strtoi(s, &s, 10, &hsig) || *s++ != ' ') { |
| 543 | fprintf(stderr, "Malformed host signal in QEMU_RTSIG_MAP\n"); |
| 544 | exit(EXIT_FAILURE); |
| 545 | } |
| 546 | if (qemu_strtoi(s, &s, 10, &count) || (*s && *s != ',')) { |
| 547 | fprintf(stderr, "Malformed signal count in QEMU_RTSIG_MAP\n"); |
| 548 | exit(EXIT_FAILURE); |
| 549 | } |
| 550 | |
| 551 | for (i = 0; i < count; i++, tsig++, hsig++) { |
| 552 | if (tsig < TARGET_SIGRTMIN || tsig > TARGET_NSIG) { |
| 553 | fprintf(stderr, "%d is not a target rt signal\n", tsig); |
| 554 | exit(EXIT_FAILURE); |
| 555 | } |
| 556 | if (hsig < SIGRTMIN || hsig > SIGRTMAX) { |
| 557 | fprintf(stderr, "%d is not a host rt signal\n", hsig); |
| 558 | exit(EXIT_FAILURE); |
| 559 | } |
| 560 | if (host_to_target_signal_table[hsig]) { |
| 561 | fprintf(stderr, "%d already maps %d\n", |
| 562 | hsig, host_to_target_signal_table[hsig]); |
| 563 | exit(EXIT_FAILURE); |
| 564 | } |
| 565 | host_to_target_signal_table[hsig] = tsig; |
| 566 | } |
| 567 | |
| 568 | if (*s) { |
| 569 | s++; |
| 570 | } else { |
| 571 | break; |
| 572 | } |
| 573 | } |
| 574 | } else { |
| 575 | /* |
| 576 | * Default host-to-target RT signal mapping. |
| 577 | * |
| 578 | * Signals are supported starting from TARGET_SIGRTMIN and going up |
| 579 | * until we run out of host realtime signals. Glibc uses the lower 2 |
| 580 | * RT signals and (hopefully) nobody uses the upper ones. |
| 581 | * This is why SIGRTMIN (34) is generally greater than __SIGRTMIN (32). |
| 582 | * To fix this properly we would need to do manual signal delivery |
| 583 | * multiplexed over a single host signal. |
| 584 | * Attempts for configure "missing" signals via sigaction will be |
| 585 | * silently ignored. |
| 586 | * |
| 587 | * Reserve two signals for internal usage (see below). |
| 588 | */ |
| 589 | |
| 590 | hsig = SIGRTMIN + 2; |
| 591 | for (tsig = TARGET_SIGRTMIN; |
| 592 | hsig <= SIGRTMAX && tsig <= TARGET_NSIG; |
| 593 | hsig++, tsig++) { |
| 594 | host_to_target_signal_table[hsig] = tsig; |
| 595 | } |
| 596 | } |
| 597 | |
| 598 | /* |
| 599 | * Remap the target SIGABRT, so that we can distinguish host abort |
| 600 | * from guest abort. When the guest registers a signal handler or |
| 601 | * calls raise(SIGABRT), the host will raise SIG_RTn. If the guest |
| 602 | * arrives at dump_core_and_abort(), we will map back to host SIGABRT |
| 603 | * so that the parent (native or emulated) sees the correct signal. |
| 604 | * Finally, also map host to guest SIGABRT so that the emulated |
| 605 | * parent sees the correct mapping from wait status. |
| 606 | */ |
| 607 | |
| 608 | host_to_target_signal_table[SIGABRT] = 0; |
| 609 | for (hsig = SIGRTMIN; hsig <= SIGRTMAX; hsig++) { |
| 610 | if (!host_to_target_signal_table[hsig]) { |
| 611 | if (host_interrupt_signal) { |
| 612 | host_to_target_signal_table[hsig] = TARGET_SIGABRT; |
| 613 | break; |
| 614 | } else { |
| 615 | host_interrupt_signal = hsig; |
| 616 | } |
| 617 | } |
| 618 | } |
| 619 | if (hsig > SIGRTMAX) { |
| 620 | fprintf(stderr, |
| 621 | "No rt signals left for interrupt and SIGABRT mapping\n"); |
| 622 | exit(EXIT_FAILURE); |
| 623 | } |
| 624 | |
| 625 | /* Invert the mapping that has already been assigned. */ |
| 626 | for (hsig = 1; hsig < _NSIG; hsig++) { |
| 627 | tsig = host_to_target_signal_table[hsig]; |
| 628 | if (tsig) { |
| 629 | if (target_to_host_signal_table[tsig]) { |
| 630 | fprintf(stderr, "%d is already mapped to %d\n", |
| 631 | tsig, target_to_host_signal_table[tsig]); |
| 632 | exit(EXIT_FAILURE); |
| 633 | } |
| 634 | target_to_host_signal_table[tsig] = hsig; |
| 635 | } |
| 636 | } |
| 637 | |
| 638 | host_to_target_signal_table[SIGABRT] = TARGET_SIGABRT; |
| 639 | |
| 640 | /* Map everything else out-of-bounds. */ |
| 641 | for (hsig = 1; hsig < _NSIG; hsig++) { |
| 642 | if (host_to_target_signal_table[hsig] == 0) { |
| 643 | host_to_target_signal_table[hsig] = TARGET_NSIG + 1; |
| 644 | } |
| 645 | } |
| 646 | for (count = 0, tsig = 1; tsig <= TARGET_NSIG; tsig++) { |
| 647 | if (target_to_host_signal_table[tsig] == 0) { |
| 648 | target_to_host_signal_table[tsig] = _NSIG; |
| 649 | count++; |
| 650 | } |
| 651 | } |
| 652 | |
| 653 | trace_signal_table_init(count); |
| 654 | } |
| 655 | |
| 656 | void signal_init(const char *rtsig_map) |
| 657 | { |
| 658 | TaskState *ts = get_task_state(thread_cpu); |
| 659 | struct sigaction act, oact; |
| 660 | |
| 661 | /* initialize signal conversion tables */ |
| 662 | signal_table_init(rtsig_map); |
| 663 | |
| 664 | /* Set the signal mask from the host mask. */ |
| 665 | sigprocmask(0, 0, &ts->signal_mask); |
| 666 | |
| 667 | sigfillset(&act.sa_mask); |
| 668 | act.sa_flags = SA_SIGINFO; |
| 669 | act.sa_sigaction = host_signal_handler; |
| 670 | |
| 671 | /* |
| 672 | * A parent process may configure ignored signals, but all other |
| 673 | * signals are default. For any target signals that have no host |
| 674 | * mapping, set to ignore. For all core_dump_signal, install our |
| 675 | * host signal handler so that we may invoke dump_core_and_abort. |
| 676 | * This includes SIGSEGV and SIGBUS, which are also need our signal |
| 677 | * handler for paging and exceptions. |
| 678 | */ |
| 679 | for (int tsig = 1; tsig <= TARGET_NSIG; tsig++) { |
| 680 | int hsig = target_to_host_signal(tsig); |
| 681 | abi_ptr thand = TARGET_SIG_IGN; |
| 682 | |
| 683 | if (hsig >= _NSIG) { |
| 684 | continue; |
| 685 | } |
| 686 | |
| 687 | /* As we force remap SIGABRT, cannot probe and install in one step. */ |
| 688 | if (tsig == TARGET_SIGABRT) { |
| 689 | sigaction(SIGABRT, NULL, &oact); |
| 690 | sigaction(hsig, &act, NULL); |
| 691 | } else { |
| 692 | struct sigaction *iact = core_dump_signal(tsig) ? &act : NULL; |
| 693 | sigaction(hsig, iact, &oact); |
| 694 | } |
| 695 | |
| 696 | if (oact.sa_sigaction != (void *)SIG_IGN) { |
| 697 | thand = TARGET_SIG_DFL; |
| 698 | } |
| 699 | sigact_table[tsig - 1]._sa_handler = thand; |
| 700 | } |
| 701 | |
| 702 | sigaction(host_interrupt_signal, &act, NULL); |
| 703 | } |
| 704 | |
| 705 | /* Force a synchronously taken signal. The kernel force_sig() function |
| 706 | * also forces the signal to "not blocked, not ignored", but for QEMU |
| 707 | * that work is done in process_pending_signals(). |
| 708 | */ |
| 709 | void force_sig(int sig) |
| 710 | { |
| 711 | CPUState *cpu = thread_cpu; |
| 712 | target_siginfo_t info = {}; |
| 713 | |
| 714 | info.si_signo = sig; |
| 715 | info.si_errno = 0; |
| 716 | info.si_code = TARGET_SI_KERNEL; |
| 717 | info._sifields._kill._pid = 0; |
| 718 | info._sifields._kill._uid = 0; |
| 719 | queue_signal(cpu_env(cpu), info.si_signo, QEMU_SI_KILL, &info); |
| 720 | } |
| 721 | |
| 722 | /* |
| 723 | * Force a synchronously taken QEMU_SI_FAULT signal. For QEMU the |
| 724 | * 'force' part is handled in process_pending_signals(). |
| 725 | */ |
| 726 | void force_sig_fault(int sig, int code, abi_ulong addr) |
| 727 | { |
| 728 | CPUState *cpu = thread_cpu; |
| 729 | target_siginfo_t info = {}; |
| 730 | |
| 731 | info.si_signo = sig; |
| 732 | info.si_errno = 0; |
| 733 | info.si_code = code; |
| 734 | info._sifields._sigfault._addr = addr; |
| 735 | queue_signal(cpu_env(cpu), sig, QEMU_SI_FAULT, &info); |
| 736 | } |
| 737 | |
| 738 | /* Force a SIGSEGV if we couldn't write to memory trying to set |
| 739 | * up the signal frame. oldsig is the signal we were trying to handle |
| 740 | * at the point of failure. |
| 741 | */ |
| 742 | #if !defined(TARGET_RISCV) |
| 743 | void force_sigsegv(int oldsig) |
| 744 | { |
| 745 | if (oldsig == SIGSEGV) { |
| 746 | /* Make sure we don't try to deliver the signal again; this will |
| 747 | * end up with handle_pending_signal() calling dump_core_and_abort(). |
| 748 | */ |
| 749 | sigact_table[oldsig - 1]._sa_handler = TARGET_SIG_DFL; |
| 750 | } |
| 751 | force_sig(TARGET_SIGSEGV); |
| 752 | } |
| 753 | #endif |
| 754 | |
| 755 | void cpu_loop_exit_sigsegv(CPUState *cpu, vaddr addr, |
| 756 | MMUAccessType access_type, bool maperr, uintptr_t ra) |
| 757 | { |
| 758 | const TCGCPUOps *tcg_ops = cpu->cc->tcg_ops; |
| 759 | |
| 760 | if (tcg_ops->record_sigsegv) { |
| 761 | tcg_ops->record_sigsegv(cpu, addr, access_type, maperr, ra); |
| 762 | } |
| 763 | |
| 764 | force_sig_fault(TARGET_SIGSEGV, |
| 765 | maperr ? TARGET_SEGV_MAPERR : TARGET_SEGV_ACCERR, |
| 766 | addr); |
| 767 | cpu->exception_index = EXCP_INTERRUPT; |
| 768 | cpu_loop_exit_restore(cpu, ra); |
| 769 | } |
| 770 | |
| 771 | void cpu_loop_exit_sigbus(CPUState *cpu, vaddr addr, |
| 772 | MMUAccessType access_type, uintptr_t ra) |
| 773 | { |
| 774 | const TCGCPUOps *tcg_ops = cpu->cc->tcg_ops; |
| 775 | |
| 776 | if (tcg_ops->record_sigbus) { |
| 777 | tcg_ops->record_sigbus(cpu, addr, access_type, ra); |
| 778 | } |
| 779 | |
| 780 | force_sig_fault(TARGET_SIGBUS, TARGET_BUS_ADRALN, addr); |
| 781 | cpu->exception_index = EXCP_INTERRUPT; |
| 782 | cpu_loop_exit_restore(cpu, ra); |
| 783 | } |
| 784 | |
| 785 | /* abort execution with signal */ |
| 786 | static G_NORETURN |
| 787 | void die_with_signal(int host_sig) |
| 788 | { |
| 789 | struct sigaction act = { |
| 790 | .sa_handler = SIG_DFL, |
| 791 | }; |
| 792 | |
| 793 | /* |
| 794 | * The proper exit code for dying from an uncaught signal is -<signal>. |
| 795 | * The kernel doesn't allow exit() or _exit() to pass a negative value. |
| 796 | * To get the proper exit code we need to actually die from an uncaught |
| 797 | * signal. Here the default signal handler is installed, we send |
| 798 | * the signal and we wait for it to arrive. |
| 799 | */ |
| 800 | sigfillset(&act.sa_mask); |
| 801 | sigaction(host_sig, &act, NULL); |
| 802 | |
| 803 | kill(getpid(), host_sig); |
| 804 | |
| 805 | /* Make sure the signal isn't masked (reusing the mask inside of act). */ |
| 806 | sigdelset(&act.sa_mask, host_sig); |
| 807 | sigsuspend(&act.sa_mask); |
| 808 | |
| 809 | /* unreachable */ |
| 810 | _exit(EXIT_FAILURE); |
| 811 | } |
| 812 | |
| 813 | static G_NORETURN |
| 814 | void dump_core_and_abort(CPUArchState *env, int target_sig) |
| 815 | { |
| 816 | CPUState *cpu = env_cpu(env); |
| 817 | TaskState *ts = get_task_state(cpu); |
| 818 | int host_sig, core_dumped = 0; |
| 819 | |
| 820 | /* On exit, undo the remapping of SIGABRT. */ |
| 821 | if (target_sig == TARGET_SIGABRT) { |
| 822 | host_sig = SIGABRT; |
| 823 | } else { |
| 824 | host_sig = target_to_host_signal(target_sig); |
| 825 | } |
| 826 | trace_user_dump_core_and_abort(env, target_sig, host_sig); |
| 827 | gdb_signalled(env, target_sig); |
| 828 | |
| 829 | /* dump core if supported by target binary format */ |
| 830 | if (core_dump_signal(target_sig) && (ts->bprm->core_dump != NULL)) { |
| 831 | stop_all_tasks(); |
| 832 | core_dumped = |
| 833 | ((*ts->bprm->core_dump)(target_sig, env) == 0); |
| 834 | } |
| 835 | if (core_dumped) { |
| 836 | /* we already dumped the core of target process, we don't want |
| 837 | * a coredump of qemu itself */ |
| 838 | struct rlimit nodump; |
| 839 | getrlimit(RLIMIT_CORE, &nodump); |
| 840 | nodump.rlim_cur=0; |
| 841 | setrlimit(RLIMIT_CORE, &nodump); |
| 842 | (void) fprintf(stderr, "qemu: uncaught target signal %d (%s) - %s\n", |
| 843 | target_sig, strsignal(host_sig), "core dumped" ); |
| 844 | } |
| 845 | |
| 846 | preexit_cleanup(env, 128 + target_sig); |
| 847 | die_with_signal(host_sig); |
| 848 | } |
| 849 | |
| 850 | /* queue a signal so that it will be send to the virtual CPU as soon |
| 851 | as possible */ |
| 852 | void queue_signal(CPUArchState *env, int sig, int si_type, |
| 853 | target_siginfo_t *info) |
| 854 | { |
| 855 | CPUState *cpu = env_cpu(env); |
| 856 | TaskState *ts = get_task_state(cpu); |
| 857 | |
| 858 | trace_user_queue_signal(env, sig); |
| 859 | |
| 860 | info->si_code = deposit32(info->si_code, 16, 16, si_type); |
| 861 | |
| 862 | ts->sync_signal.info = *info; |
| 863 | ts->sync_signal.pending = sig; |
| 864 | /* signal that a new signal is pending */ |
| 865 | qatomic_set(&ts->signal_pending, 1); |
| 866 | } |
| 867 | |
| 868 | |
| 869 | /* Adjust the signal context to rewind out of safe-syscall if we're in it */ |
| 870 | static inline void rewind_if_in_safe_syscall(void *puc) |
| 871 | { |
| 872 | host_sigcontext *uc = (host_sigcontext *)puc; |
| 873 | uintptr_t pcreg = host_signal_pc(uc); |
| 874 | |
| 875 | if (pcreg > (uintptr_t)safe_syscall_start |
| 876 | && pcreg < (uintptr_t)safe_syscall_end) { |
| 877 | host_signal_set_pc(uc, (uintptr_t)safe_syscall_start); |
| 878 | } |
| 879 | } |
| 880 | |
| 881 | static G_NORETURN |
| 882 | void die_from_signal(siginfo_t *info) |
| 883 | { |
| 884 | char sigbuf[4], codebuf[12]; |
| 885 | const char *sig, *code = NULL; |
| 886 | |
| 887 | switch (info->si_signo) { |
| 888 | case SIGSEGV: |
| 889 | sig = "SEGV"; |
| 890 | switch (info->si_code) { |
| 891 | case SEGV_MAPERR: |
| 892 | code = "MAPERR"; |
| 893 | break; |
| 894 | case SEGV_ACCERR: |
| 895 | code = "ACCERR"; |
| 896 | break; |
| 897 | } |
| 898 | break; |
| 899 | case SIGBUS: |
| 900 | sig = "BUS"; |
| 901 | switch (info->si_code) { |
| 902 | case BUS_ADRALN: |
| 903 | code = "ADRALN"; |
| 904 | break; |
| 905 | case BUS_ADRERR: |
| 906 | code = "ADRERR"; |
| 907 | break; |
| 908 | } |
| 909 | break; |
| 910 | case SIGILL: |
| 911 | sig = "ILL"; |
| 912 | switch (info->si_code) { |
| 913 | case ILL_ILLOPC: |
| 914 | code = "ILLOPC"; |
| 915 | break; |
| 916 | case ILL_ILLOPN: |
| 917 | code = "ILLOPN"; |
| 918 | break; |
| 919 | case ILL_ILLADR: |
| 920 | code = "ILLADR"; |
| 921 | break; |
| 922 | case ILL_PRVOPC: |
| 923 | code = "PRVOPC"; |
| 924 | break; |
| 925 | case ILL_PRVREG: |
| 926 | code = "PRVREG"; |
| 927 | break; |
| 928 | case ILL_COPROC: |
| 929 | code = "COPROC"; |
| 930 | break; |
| 931 | } |
| 932 | break; |
| 933 | case SIGFPE: |
| 934 | sig = "FPE"; |
| 935 | switch (info->si_code) { |
| 936 | case FPE_INTDIV: |
| 937 | code = "INTDIV"; |
| 938 | break; |
| 939 | case FPE_INTOVF: |
| 940 | code = "INTOVF"; |
| 941 | break; |
| 942 | } |
| 943 | break; |
| 944 | case SIGTRAP: |
| 945 | sig = "TRAP"; |
| 946 | break; |
| 947 | default: |
| 948 | snprintf(sigbuf, sizeof(sigbuf), "%d", info->si_signo); |
| 949 | sig = sigbuf; |
| 950 | break; |
| 951 | } |
| 952 | if (code == NULL) { |
| 953 | snprintf(codebuf, sizeof(sigbuf), "%d", info->si_code); |
| 954 | code = codebuf; |
| 955 | } |
| 956 | |
| 957 | error_report("QEMU internal SIG%s {code=%s, addr=%p}", |
| 958 | sig, code, info->si_addr); |
| 959 | die_with_signal(info->si_signo); |
| 960 | } |
| 961 | |
| 962 | static void host_sigsegv_handler(CPUState *cpu, siginfo_t *info, |
| 963 | host_sigcontext *uc) |
| 964 | { |
| 965 | uintptr_t host_addr = (uintptr_t)info->si_addr; |
| 966 | /* |
| 967 | * Convert forcefully to guest address space: addresses outside |
| 968 | * reserved_va are still valid to report via SEGV_MAPERR. |
| 969 | */ |
| 970 | bool is_valid = h2g_valid(host_addr); |
| 971 | abi_ptr guest_addr = h2g_nocheck(host_addr); |
| 972 | uintptr_t pc = host_signal_pc(uc); |
| 973 | bool is_write = host_signal_write(info, uc); |
| 974 | MMUAccessType access_type = adjust_signal_pc(&pc, is_write); |
| 975 | bool maperr; |
| 976 | |
| 977 | /* If this was a write to a TB protected page, restart. */ |
| 978 | if (is_write |
| 979 | && is_valid |
| 980 | && info->si_code == SEGV_ACCERR |
| 981 | && handle_sigsegv_accerr_write(cpu, host_signal_mask(uc), |
| 982 | pc, guest_addr)) { |
| 983 | return; |
| 984 | } |
| 985 | |
| 986 | /* |
| 987 | * If the access was not on behalf of the guest, within the executable |
| 988 | * mapping of the generated code buffer, then it is a host bug. |
| 989 | */ |
| 990 | if (access_type != MMU_INST_FETCH |
| 991 | && !in_code_gen_buffer((void *)(pc - tcg_splitwx_diff))) { |
| 992 | die_from_signal(info); |
| 993 | } |
| 994 | |
| 995 | maperr = true; |
| 996 | if (is_valid && info->si_code == SEGV_ACCERR) { |
| 997 | /* |
| 998 | * With reserved_va, the whole address space is PROT_NONE, |
| 999 | * which means that we may get ACCERR when we want MAPERR. |
| 1000 | */ |
| 1001 | if (page_get_flags(guest_addr) & PAGE_VALID) { |
| 1002 | maperr = false; |
| 1003 | } else { |
| 1004 | info->si_code = SEGV_MAPERR; |
| 1005 | } |
| 1006 | } |
| 1007 | |
| 1008 | sigprocmask(SIG_SETMASK, host_signal_mask(uc), NULL); |
| 1009 | cpu_loop_exit_sigsegv(cpu, guest_addr, access_type, maperr, pc); |
| 1010 | } |
| 1011 | |
| 1012 | static uintptr_t host_sigbus_handler(CPUState *cpu, siginfo_t *info, |
| 1013 | host_sigcontext *uc) |
| 1014 | { |
| 1015 | uintptr_t pc = host_signal_pc(uc); |
| 1016 | bool is_write = host_signal_write(info, uc); |
| 1017 | MMUAccessType access_type = adjust_signal_pc(&pc, is_write); |
| 1018 | |
| 1019 | /* |
| 1020 | * If the access was not on behalf of the guest, within the executable |
| 1021 | * mapping of the generated code buffer, then it is a host bug. |
| 1022 | */ |
| 1023 | if (!in_code_gen_buffer((void *)(pc - tcg_splitwx_diff))) { |
| 1024 | die_from_signal(info); |
| 1025 | } |
| 1026 | |
| 1027 | if (info->si_code == BUS_ADRALN) { |
| 1028 | uintptr_t host_addr = (uintptr_t)info->si_addr; |
| 1029 | abi_ptr guest_addr = h2g_nocheck(host_addr); |
| 1030 | |
| 1031 | sigprocmask(SIG_SETMASK, host_signal_mask(uc), NULL); |
| 1032 | cpu_loop_exit_sigbus(cpu, guest_addr, access_type, pc); |
| 1033 | } |
| 1034 | return pc; |
| 1035 | } |
| 1036 | |
| 1037 | static void host_signal_handler(int host_sig, siginfo_t *info, void *puc) |
| 1038 | { |
| 1039 | CPUState *cpu = thread_cpu; |
| 1040 | CPUArchState *env = cpu_env(cpu); |
| 1041 | TaskState *ts = get_task_state(cpu); |
| 1042 | target_siginfo_t tinfo; |
| 1043 | host_sigcontext *uc = puc; |
| 1044 | struct emulated_sigtable *k; |
| 1045 | int guest_sig; |
| 1046 | uintptr_t pc = 0; |
| 1047 | bool sync_sig = false; |
| 1048 | void *sigmask; |
| 1049 | |
| 1050 | if (host_sig == host_interrupt_signal) { |
| 1051 | ts->signal_pending = 1; |
| 1052 | cpu_exit(thread_cpu); |
| 1053 | return; |
| 1054 | } |
| 1055 | |
| 1056 | /* |
| 1057 | * Non-spoofed SIGSEGV and SIGBUS are synchronous, and need special |
| 1058 | * handling wrt signal blocking and unwinding. Non-spoofed SIGILL, |
| 1059 | * SIGFPE, SIGTRAP are always host bugs. |
| 1060 | */ |
| 1061 | if (info->si_code > 0) { |
| 1062 | switch (host_sig) { |
| 1063 | case SIGSEGV: |
| 1064 | /* Only returns on handle_sigsegv_accerr_write success. */ |
| 1065 | host_sigsegv_handler(cpu, info, uc); |
| 1066 | return; |
| 1067 | case SIGBUS: |
| 1068 | pc = host_sigbus_handler(cpu, info, uc); |
| 1069 | sync_sig = true; |
| 1070 | break; |
| 1071 | case SIGILL: |
| 1072 | case SIGFPE: |
| 1073 | case SIGTRAP: |
| 1074 | die_from_signal(info); |
| 1075 | } |
| 1076 | } |
| 1077 | |
| 1078 | /* get target signal number */ |
| 1079 | guest_sig = host_to_target_signal(host_sig); |
| 1080 | if (guest_sig < 1 || guest_sig > TARGET_NSIG) { |
| 1081 | return; |
| 1082 | } |
| 1083 | trace_user_host_signal(env, host_sig, guest_sig); |
| 1084 | |
| 1085 | host_to_target_siginfo_noswap(&tinfo, info); |
| 1086 | k = &ts->sigtab[guest_sig - 1]; |
| 1087 | k->info = tinfo; |
| 1088 | k->pending = guest_sig; |
| 1089 | ts->signal_pending = 1; |
| 1090 | |
| 1091 | /* |
| 1092 | * For synchronous signals, unwind the cpu state to the faulting |
| 1093 | * insn and then exit back to the main loop so that the signal |
| 1094 | * is delivered immediately. |
| 1095 | */ |
| 1096 | if (sync_sig) { |
| 1097 | cpu->exception_index = EXCP_INTERRUPT; |
| 1098 | cpu_loop_exit_restore(cpu, pc); |
| 1099 | } |
| 1100 | |
| 1101 | rewind_if_in_safe_syscall(puc); |
| 1102 | |
| 1103 | /* |
| 1104 | * Block host signals until target signal handler entered. We |
| 1105 | * can't block SIGSEGV or SIGBUS while we're executing guest |
| 1106 | * code in case the guest code provokes one in the window between |
| 1107 | * now and it getting out to the main loop. Signals will be |
| 1108 | * unblocked again in process_pending_signals(). |
| 1109 | * |
| 1110 | * WARNING: we cannot use sigfillset() here because the sigmask |
| 1111 | * field is a kernel sigset_t, which is much smaller than the |
| 1112 | * libc sigset_t which sigfillset() operates on. Using sigfillset() |
| 1113 | * would write 0xff bytes off the end of the structure and trash |
| 1114 | * data on the struct. |
| 1115 | */ |
| 1116 | sigmask = host_signal_mask(uc); |
| 1117 | memset(sigmask, 0xff, SIGSET_T_SIZE); |
| 1118 | sigdelset(sigmask, SIGSEGV); |
| 1119 | sigdelset(sigmask, SIGBUS); |
| 1120 | |
| 1121 | /* interrupt the virtual CPU as soon as possible */ |
| 1122 | cpu_exit(thread_cpu); |
| 1123 | } |
| 1124 | |
| 1125 | /* do_sigaltstack() returns target values and errnos. */ |
| 1126 | /* compare linux/kernel/signal.c:do_sigaltstack() */ |
| 1127 | abi_long do_sigaltstack(abi_ulong uss_addr, abi_ulong uoss_addr, |
| 1128 | CPUArchState *env) |
| 1129 | { |
| 1130 | target_stack_t oss, *uoss = NULL; |
| 1131 | abi_long ret = -TARGET_EFAULT; |
| 1132 | |
| 1133 | if (uoss_addr) { |
| 1134 | /* Verify writability now, but do not alter user memory yet. */ |
| 1135 | if (!lock_user_struct(VERIFY_WRITE, uoss, uoss_addr, 0)) { |
| 1136 | goto out; |
| 1137 | } |
| 1138 | target_save_altstack(&oss, env); |
| 1139 | } |
| 1140 | |
| 1141 | if (uss_addr) { |
| 1142 | target_stack_t *uss; |
| 1143 | |
| 1144 | if (!lock_user_struct(VERIFY_READ, uss, uss_addr, 1)) { |
| 1145 | goto out; |
| 1146 | } |
| 1147 | ret = target_restore_altstack(uss, env); |
| 1148 | if (ret) { |
| 1149 | goto out; |
| 1150 | } |
| 1151 | } |
| 1152 | |
| 1153 | if (uoss_addr) { |
| 1154 | memcpy(uoss, &oss, sizeof(oss)); |
| 1155 | unlock_user_struct(uoss, uoss_addr, 1); |
| 1156 | uoss = NULL; |
| 1157 | } |
| 1158 | ret = 0; |
| 1159 | |
| 1160 | out: |
| 1161 | if (uoss) { |
| 1162 | unlock_user_struct(uoss, uoss_addr, 0); |
| 1163 | } |
| 1164 | return ret; |
| 1165 | } |
| 1166 | |
| 1167 | /* do_sigaction() return target values and host errnos */ |
| 1168 | int do_sigaction(int sig, const struct target_sigaction *act, |
| 1169 | struct target_sigaction *oact, abi_ulong ka_restorer) |
| 1170 | { |
| 1171 | struct target_sigaction *k; |
| 1172 | int host_sig; |
| 1173 | int ret = 0; |
| 1174 | |
| 1175 | trace_signal_do_sigaction_guest(sig, TARGET_NSIG); |
| 1176 | |
| 1177 | if (sig < 1 || sig > TARGET_NSIG) { |
| 1178 | return -TARGET_EINVAL; |
| 1179 | } |
| 1180 | |
| 1181 | if (act && (sig == TARGET_SIGKILL || sig == TARGET_SIGSTOP)) { |
| 1182 | return -TARGET_EINVAL; |
| 1183 | } |
| 1184 | |
| 1185 | if (block_signals()) { |
| 1186 | return -QEMU_ERESTARTSYS; |
| 1187 | } |
| 1188 | |
| 1189 | k = &sigact_table[sig - 1]; |
| 1190 | if (oact) { |
| 1191 | __put_user(k->_sa_handler, &oact->_sa_handler); |
| 1192 | __put_user(k->sa_flags, &oact->sa_flags); |
| 1193 | #ifdef TARGET_ARCH_HAS_SA_RESTORER |
| 1194 | __put_user(k->sa_restorer, &oact->sa_restorer); |
| 1195 | #endif |
| 1196 | /* Not swapped. */ |
| 1197 | oact->sa_mask = k->sa_mask; |
| 1198 | } |
| 1199 | if (act) { |
| 1200 | __get_user(k->_sa_handler, &act->_sa_handler); |
| 1201 | __get_user(k->sa_flags, &act->sa_flags); |
| 1202 | #ifdef TARGET_ARCH_HAS_SA_RESTORER |
| 1203 | __get_user(k->sa_restorer, &act->sa_restorer); |
| 1204 | #endif |
| 1205 | #ifdef TARGET_ARCH_HAS_KA_RESTORER |
| 1206 | k->ka_restorer = ka_restorer; |
| 1207 | #endif |
| 1208 | /* To be swapped in target_to_host_sigset. */ |
| 1209 | k->sa_mask = act->sa_mask; |
| 1210 | |
| 1211 | /* we update the host linux signal state */ |
| 1212 | host_sig = target_to_host_signal(sig); |
| 1213 | trace_signal_do_sigaction_host(host_sig, TARGET_NSIG); |
| 1214 | if (host_sig > SIGRTMAX) { |
| 1215 | /* we don't have enough host signals to map all target signals */ |
| 1216 | qemu_log_mask(LOG_UNIMP, "Unsupported target signal #%d, ignored\n", |
| 1217 | sig); |
| 1218 | /* |
| 1219 | * we don't return an error here because some programs try to |
| 1220 | * register an handler for all possible rt signals even if they |
| 1221 | * don't need it. |
| 1222 | * An error here can abort them whereas there can be no problem |
| 1223 | * to not have the signal available later. |
| 1224 | * This is the case for golang, |
| 1225 | * See https://github.com/golang/go/issues/33746 |
| 1226 | * So we silently ignore the error. |
| 1227 | */ |
| 1228 | return 0; |
| 1229 | } |
| 1230 | if (host_sig != SIGSEGV && host_sig != SIGBUS) { |
| 1231 | struct sigaction act1; |
| 1232 | |
| 1233 | sigfillset(&act1.sa_mask); |
| 1234 | act1.sa_flags = SA_SIGINFO; |
| 1235 | if (k->_sa_handler == TARGET_SIG_IGN) { |
| 1236 | /* |
| 1237 | * It is important to update the host kernel signal ignore |
| 1238 | * state to avoid getting unexpected interrupted syscalls. |
| 1239 | */ |
| 1240 | act1.sa_sigaction = (void *)SIG_IGN; |
| 1241 | } else if (k->_sa_handler == TARGET_SIG_DFL) { |
| 1242 | if (core_dump_signal(sig)) { |
| 1243 | act1.sa_sigaction = host_signal_handler; |
| 1244 | } else { |
| 1245 | act1.sa_sigaction = (void *)SIG_DFL; |
| 1246 | } |
| 1247 | } else { |
| 1248 | act1.sa_sigaction = host_signal_handler; |
| 1249 | if (k->sa_flags & TARGET_SA_RESTART) { |
| 1250 | act1.sa_flags |= SA_RESTART; |
| 1251 | } |
| 1252 | } |
| 1253 | ret = sigaction(host_sig, &act1, NULL); |
| 1254 | } |
| 1255 | } |
| 1256 | return ret; |
| 1257 | } |
| 1258 | |
| 1259 | static void handle_pending_signal(CPUArchState *cpu_env, int sig, |
| 1260 | struct emulated_sigtable *k) |
| 1261 | { |
| 1262 | CPUState *cpu = env_cpu(cpu_env); |
| 1263 | abi_ulong handler; |
| 1264 | sigset_t set; |
| 1265 | target_siginfo_t unswapped; |
| 1266 | target_sigset_t target_old_set; |
| 1267 | struct target_sigaction *sa; |
| 1268 | TaskState *ts = get_task_state(cpu); |
| 1269 | |
| 1270 | trace_user_handle_signal(cpu_env, sig); |
| 1271 | /* dequeue signal */ |
| 1272 | k->pending = 0; |
| 1273 | |
| 1274 | /* |
| 1275 | * Writes out siginfo values byteswapped, accordingly to the target. |
| 1276 | * It also cleans the si_type from si_code making it correct for |
| 1277 | * the target. We must hold on to the original unswapped copy for |
| 1278 | * strace below, because si_type is still required there. |
| 1279 | */ |
| 1280 | if (unlikely(qemu_loglevel_mask(LOG_STRACE))) { |
| 1281 | unswapped = k->info; |
| 1282 | } |
| 1283 | tswap_siginfo(&k->info, &k->info); |
| 1284 | |
| 1285 | sig = gdb_handlesig(cpu, sig, NULL, &k->info, sizeof(k->info)); |
| 1286 | if (!sig) { |
| 1287 | sa = NULL; |
| 1288 | handler = TARGET_SIG_IGN; |
| 1289 | } else { |
| 1290 | sa = &sigact_table[sig - 1]; |
| 1291 | handler = sa->_sa_handler; |
| 1292 | } |
| 1293 | |
| 1294 | if (unlikely(qemu_loglevel_mask(LOG_STRACE))) { |
| 1295 | print_taken_signal(sig, &unswapped); |
| 1296 | } |
| 1297 | |
| 1298 | if (handler == TARGET_SIG_DFL) { |
| 1299 | /* default handler : ignore some signal. The other are job control or fatal */ |
| 1300 | if (sig == TARGET_SIGTSTP || sig == TARGET_SIGTTIN || sig == TARGET_SIGTTOU) { |
| 1301 | kill(getpid(),SIGSTOP); |
| 1302 | } else if (sig != TARGET_SIGCHLD && |
| 1303 | sig != TARGET_SIGURG && |
| 1304 | sig != TARGET_SIGWINCH && |
| 1305 | sig != TARGET_SIGCONT) { |
| 1306 | dump_core_and_abort(cpu_env, sig); |
| 1307 | } |
| 1308 | } else if (handler == TARGET_SIG_IGN) { |
| 1309 | /* ignore sig */ |
| 1310 | } else if (handler == TARGET_SIG_ERR) { |
| 1311 | dump_core_and_abort(cpu_env, sig); |
| 1312 | } else { |
| 1313 | /* compute the blocked signals during the handler execution */ |
| 1314 | sigset_t *blocked_set; |
| 1315 | |
| 1316 | target_to_host_sigset(&set, &sa->sa_mask); |
| 1317 | /* SA_NODEFER indicates that the current signal should not be |
| 1318 | blocked during the handler */ |
| 1319 | if (!(sa->sa_flags & TARGET_SA_NODEFER)) |
| 1320 | sigaddset(&set, target_to_host_signal(sig)); |
| 1321 | |
| 1322 | /* save the previous blocked signal state to restore it at the |
| 1323 | end of the signal execution (see do_sigreturn) */ |
| 1324 | host_to_target_sigset_internal(&target_old_set, &ts->signal_mask); |
| 1325 | |
| 1326 | /* block signals in the handler */ |
| 1327 | blocked_set = ts->in_sigsuspend ? |
| 1328 | &ts->sigsuspend_mask : &ts->signal_mask; |
| 1329 | sigorset(&ts->signal_mask, blocked_set, &set); |
| 1330 | ts->in_sigsuspend = 0; |
| 1331 | |
| 1332 | /* if the CPU is in VM86 mode, we restore the 32 bit values */ |
| 1333 | #if defined(TARGET_I386) && !defined(TARGET_X86_64) |
| 1334 | { |
| 1335 | CPUX86State *env = cpu_env; |
| 1336 | if (env->eflags & VM_MASK) |
| 1337 | save_v86_state(env); |
| 1338 | } |
| 1339 | #endif |
| 1340 | /* prepare the stack frame of the virtual CPU */ |
| 1341 | #if defined(TARGET_ARCH_HAS_SETUP_FRAME) |
| 1342 | if (sa->sa_flags & TARGET_SA_SIGINFO) { |
| 1343 | setup_rt_frame(sig, sa, &k->info, &target_old_set, cpu_env); |
| 1344 | } else { |
| 1345 | setup_frame(sig, sa, &target_old_set, cpu_env); |
| 1346 | } |
| 1347 | #else |
| 1348 | /* These targets do not have traditional signals. */ |
| 1349 | setup_rt_frame(sig, sa, &k->info, &target_old_set, cpu_env); |
| 1350 | #endif |
| 1351 | if (sa->sa_flags & TARGET_SA_RESETHAND) { |
| 1352 | sa->_sa_handler = TARGET_SIG_DFL; |
| 1353 | } |
| 1354 | } |
| 1355 | } |
| 1356 | |
| 1357 | void process_pending_signals(CPUArchState *cpu_env) |
| 1358 | { |
| 1359 | CPUState *cpu = env_cpu(cpu_env); |
| 1360 | int sig; |
| 1361 | TaskState *ts = get_task_state(cpu); |
| 1362 | sigset_t set; |
| 1363 | sigset_t *blocked_set; |
| 1364 | |
| 1365 | while (qatomic_read(&ts->signal_pending)) { |
| 1366 | sigfillset(&set); |
| 1367 | sigprocmask(SIG_SETMASK, &set, 0); |
| 1368 | |
| 1369 | restart_scan: |
| 1370 | sig = ts->sync_signal.pending; |
| 1371 | if (sig) { |
| 1372 | /* Synchronous signals are forced, |
| 1373 | * see force_sig_info() and callers in Linux |
| 1374 | * Note that not all of our queue_signal() calls in QEMU correspond |
| 1375 | * to force_sig_info() calls in Linux (some are send_sig_info()). |
| 1376 | * However it seems like a kernel bug to me to allow the process |
| 1377 | * to block a synchronous signal since it could then just end up |
| 1378 | * looping round and round indefinitely. |
| 1379 | */ |
| 1380 | if (sigismember(&ts->signal_mask, target_to_host_signal_table[sig]) |
| 1381 | || sigact_table[sig - 1]._sa_handler == TARGET_SIG_IGN) { |
| 1382 | sigdelset(&ts->signal_mask, target_to_host_signal_table[sig]); |
| 1383 | sigact_table[sig - 1]._sa_handler = TARGET_SIG_DFL; |
| 1384 | } |
| 1385 | |
| 1386 | handle_pending_signal(cpu_env, sig, &ts->sync_signal); |
| 1387 | /* |
| 1388 | * Restart scan from the beginning, as handle_pending_signal |
| 1389 | * might have resulted in a new synchronous signal (eg SIGSEGV). |
| 1390 | */ |
| 1391 | goto restart_scan; |
| 1392 | } |
| 1393 | |
| 1394 | for (sig = 1; sig <= TARGET_NSIG; sig++) { |
| 1395 | blocked_set = ts->in_sigsuspend ? |
| 1396 | &ts->sigsuspend_mask : &ts->signal_mask; |
| 1397 | |
| 1398 | if (ts->sigtab[sig - 1].pending && |
| 1399 | (!sigismember(blocked_set, |
| 1400 | target_to_host_signal_table[sig]))) { |
| 1401 | handle_pending_signal(cpu_env, sig, &ts->sigtab[sig - 1]); |
| 1402 | /* Restart scan, explained above. */ |
| 1403 | goto restart_scan; |
| 1404 | } |
| 1405 | } |
| 1406 | |
| 1407 | /* if no signal is pending, unblock signals and recheck (the act |
| 1408 | * of unblocking might cause us to take another host signal which |
| 1409 | * will set signal_pending again). |
| 1410 | */ |
| 1411 | qatomic_set(&ts->signal_pending, 0); |
| 1412 | ts->in_sigsuspend = 0; |
| 1413 | set = ts->signal_mask; |
| 1414 | sigdelset(&set, SIGSEGV); |
| 1415 | sigdelset(&set, SIGBUS); |
| 1416 | sigprocmask(SIG_SETMASK, &set, 0); |
| 1417 | } |
| 1418 | ts->in_sigsuspend = 0; |
| 1419 | } |
| 1420 | |
| 1421 | int process_sigsuspend_mask(sigset_t **pset, target_ulong sigset, |
| 1422 | target_ulong sigsize) |
| 1423 | { |
| 1424 | TaskState *ts = get_task_state(thread_cpu); |
| 1425 | sigset_t *host_set = &ts->sigsuspend_mask; |
| 1426 | target_sigset_t *target_sigset; |
| 1427 | |
| 1428 | if (sigsize != sizeof(*target_sigset)) { |
| 1429 | /* Like the kernel, we enforce correct size sigsets */ |
| 1430 | return -TARGET_EINVAL; |
| 1431 | } |
| 1432 | |
| 1433 | target_sigset = lock_user(VERIFY_READ, sigset, sigsize, 1); |
| 1434 | if (!target_sigset) { |
| 1435 | return -TARGET_EFAULT; |
| 1436 | } |
| 1437 | target_to_host_sigset(host_set, target_sigset); |
| 1438 | unlock_user(target_sigset, sigset, 0); |
| 1439 | |
| 1440 | *pset = host_set; |
| 1441 | return 0; |
| 1442 | } |