1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _LINUX_SIGNAL_H 3 #define _LINUX_SIGNAL_H 4 5 #include <linux/bug.h> 6 #include <linux/signal_types.h> 7 #include <linux/string.h> 8 9 struct task_struct; 10 11 /* for sysctl */ 12 extern int print_fatal_signals; 13 14 static inline void copy_siginfo(kernel_siginfo_t *to, 15 const kernel_siginfo_t *from) 16 { 17 memcpy(to, from, sizeof(*to)); 18 } 19 20 static inline void clear_siginfo(kernel_siginfo_t *info) 21 { 22 memset(info, 0, sizeof(*info)); 23 } 24 25 #define SI_EXPANSION_SIZE (sizeof(struct siginfo) - sizeof(struct kernel_siginfo)) 26 27 static inline void copy_siginfo_to_external(siginfo_t *to, 28 const kernel_siginfo_t *from) 29 { 30 memcpy(to, from, sizeof(*from)); 31 memset(((char *)to) + sizeof(struct kernel_siginfo), 0, 32 SI_EXPANSION_SIZE); 33 } 34 35 int copy_siginfo_to_user(siginfo_t __user *to, const kernel_siginfo_t *from); 36 int copy_siginfo_from_user(kernel_siginfo_t *to, const siginfo_t __user *from); 37 38 enum siginfo_layout { 39 SIL_KILL, 40 SIL_TIMER, 41 SIL_POLL, 42 SIL_FAULT, 43 SIL_FAULT_MCEERR, 44 SIL_FAULT_BNDERR, 45 SIL_FAULT_PKUERR, 46 SIL_PERF_EVENT, 47 SIL_CHLD, 48 SIL_RT, 49 SIL_SYS, 50 }; 51 52 enum siginfo_layout siginfo_layout(unsigned sig, int si_code); 53 54 /* 55 * Define some primitives to manipulate sigset_t. 56 */ 57 58 #ifndef __HAVE_ARCH_SIG_BITOPS 59 #include <linux/bitops.h> 60 61 /* We don't use <linux/bitops.h> for these because there is no need to 62 be atomic. */ 63 static inline void sigaddset(sigset_t *set, int _sig) 64 { 65 unsigned long sig = _sig - 1; 66 if (_NSIG_WORDS == 1) 67 set->sig[0] |= 1UL << sig; 68 else 69 set->sig[sig / _NSIG_BPW] |= 1UL << (sig % _NSIG_BPW); 70 } 71 72 static inline void sigdelset(sigset_t *set, int _sig) 73 { 74 unsigned long sig = _sig - 1; 75 if (_NSIG_WORDS == 1) 76 set->sig[0] &= ~(1UL << sig); 77 else 78 set->sig[sig / _NSIG_BPW] &= ~(1UL << (sig % _NSIG_BPW)); 79 } 80 81 static inline int sigismember(sigset_t *set, int _sig) 82 { 83 unsigned long sig = _sig - 1; 84 if (_NSIG_WORDS == 1) 85 return 1 & (set->sig[0] >> sig); 86 else 87 return 1 & (set->sig[sig / _NSIG_BPW] >> (sig % _NSIG_BPW)); 88 } 89 90 #endif /* __HAVE_ARCH_SIG_BITOPS */ 91 92 static inline int sigisemptyset(sigset_t *set) 93 { 94 switch (_NSIG_WORDS) { 95 case 4: 96 return (set->sig[3] | set->sig[2] | 97 set->sig[1] | set->sig[0]) == 0; 98 case 2: 99 return (set->sig[1] | set->sig[0]) == 0; 100 case 1: 101 return set->sig[0] == 0; 102 default: 103 BUILD_BUG(); 104 return 0; 105 } 106 } 107 108 static inline int sigequalsets(const sigset_t *set1, const sigset_t *set2) 109 { 110 switch (_NSIG_WORDS) { 111 case 4: 112 return (set1->sig[3] == set2->sig[3]) && 113 (set1->sig[2] == set2->sig[2]) && 114 (set1->sig[1] == set2->sig[1]) && 115 (set1->sig[0] == set2->sig[0]); 116 case 2: 117 return (set1->sig[1] == set2->sig[1]) && 118 (set1->sig[0] == set2->sig[0]); 119 case 1: 120 return set1->sig[0] == set2->sig[0]; 121 } 122 return 0; 123 } 124 125 #define sigmask(sig) (1UL << ((sig) - 1)) 126 127 #ifndef __HAVE_ARCH_SIG_SETOPS 128 #include <linux/string.h> 129 130 #define _SIG_SET_BINOP(name, op) \ 131 static inline void name(sigset_t *r, const sigset_t *a, const sigset_t *b) \ 132 { \ 133 unsigned long a0, a1, a2, a3, b0, b1, b2, b3; \ 134 \ 135 switch (_NSIG_WORDS) { \ 136 case 4: \ 137 a3 = a->sig[3]; a2 = a->sig[2]; \ 138 b3 = b->sig[3]; b2 = b->sig[2]; \ 139 r->sig[3] = op(a3, b3); \ 140 r->sig[2] = op(a2, b2); \ 141 fallthrough; \ 142 case 2: \ 143 a1 = a->sig[1]; b1 = b->sig[1]; \ 144 r->sig[1] = op(a1, b1); \ 145 fallthrough; \ 146 case 1: \ 147 a0 = a->sig[0]; b0 = b->sig[0]; \ 148 r->sig[0] = op(a0, b0); \ 149 break; \ 150 default: \ 151 BUILD_BUG(); \ 152 } \ 153 } 154 155 #define _sig_or(x,y) ((x) | (y)) 156 _SIG_SET_BINOP(sigorsets, _sig_or) 157 158 #define _sig_and(x,y) ((x) & (y)) 159 _SIG_SET_BINOP(sigandsets, _sig_and) 160 161 #define _sig_andn(x,y) ((x) & ~(y)) 162 _SIG_SET_BINOP(sigandnsets, _sig_andn) 163 164 #undef _SIG_SET_BINOP 165 #undef _sig_or 166 #undef _sig_and 167 #undef _sig_andn 168 169 #define _SIG_SET_OP(name, op) \ 170 static inline void name(sigset_t *set) \ 171 { \ 172 switch (_NSIG_WORDS) { \ 173 case 4: set->sig[3] = op(set->sig[3]); \ 174 set->sig[2] = op(set->sig[2]); \ 175 fallthrough; \ 176 case 2: set->sig[1] = op(set->sig[1]); \ 177 fallthrough; \ 178 case 1: set->sig[0] = op(set->sig[0]); \ 179 break; \ 180 default: \ 181 BUILD_BUG(); \ 182 } \ 183 } 184 185 #define _sig_not(x) (~(x)) 186 _SIG_SET_OP(signotset, _sig_not) 187 188 #undef _SIG_SET_OP 189 #undef _sig_not 190 191 static inline void sigemptyset(sigset_t *set) 192 { 193 switch (_NSIG_WORDS) { 194 default: 195 memset(set, 0, sizeof(sigset_t)); 196 break; 197 case 2: set->sig[1] = 0; 198 fallthrough; 199 case 1: set->sig[0] = 0; 200 break; 201 } 202 } 203 204 static inline void sigfillset(sigset_t *set) 205 { 206 switch (_NSIG_WORDS) { 207 default: 208 memset(set, -1, sizeof(sigset_t)); 209 break; 210 case 2: set->sig[1] = -1; 211 fallthrough; 212 case 1: set->sig[0] = -1; 213 break; 214 } 215 } 216 217 /* Some extensions for manipulating the low 32 signals in particular. */ 218 219 static inline void sigaddsetmask(sigset_t *set, unsigned long mask) 220 { 221 set->sig[0] |= mask; 222 } 223 224 static inline void sigdelsetmask(sigset_t *set, unsigned long mask) 225 { 226 set->sig[0] &= ~mask; 227 } 228 229 static inline int sigtestsetmask(sigset_t *set, unsigned long mask) 230 { 231 return (set->sig[0] & mask) != 0; 232 } 233 234 static inline void siginitset(sigset_t *set, unsigned long mask) 235 { 236 set->sig[0] = mask; 237 switch (_NSIG_WORDS) { 238 default: 239 memset(&set->sig[1], 0, sizeof(long)*(_NSIG_WORDS-1)); 240 break; 241 case 2: set->sig[1] = 0; 242 break; 243 case 1: ; 244 } 245 } 246 247 static inline void siginitsetinv(sigset_t *set, unsigned long mask) 248 { 249 set->sig[0] = ~mask; 250 switch (_NSIG_WORDS) { 251 default: 252 memset(&set->sig[1], -1, sizeof(long)*(_NSIG_WORDS-1)); 253 break; 254 case 2: set->sig[1] = -1; 255 break; 256 case 1: ; 257 } 258 } 259 260 #endif /* __HAVE_ARCH_SIG_SETOPS */ 261 262 static inline void init_sigpending(struct sigpending *sig) 263 { 264 sigemptyset(&sig->signal); 265 INIT_LIST_HEAD(&sig->list); 266 } 267 268 extern void flush_sigqueue(struct sigpending *queue); 269 extern void exit_task_sigqueue_cache(struct task_struct *tsk); 270 271 /* Test if 'sig' is valid signal. Use this instead of testing _NSIG directly */ 272 static inline int valid_signal(unsigned long sig) 273 { 274 return sig <= _NSIG ? 1 : 0; 275 } 276 277 struct timespec; 278 struct pt_regs; 279 enum pid_type; 280 281 extern int next_signal(struct sigpending *pending, sigset_t *mask); 282 extern int do_send_sig_info(int sig, struct kernel_siginfo *info, 283 struct task_struct *p, enum pid_type type); 284 extern int group_send_sig_info(int sig, struct kernel_siginfo *info, 285 struct task_struct *p, enum pid_type type); 286 extern int __group_send_sig_info(int, struct kernel_siginfo *, struct task_struct *); 287 extern int sigprocmask(int, sigset_t *, sigset_t *); 288 extern void set_current_blocked(sigset_t *); 289 extern void __set_current_blocked(const sigset_t *); 290 extern int show_unhandled_signals; 291 292 extern bool get_signal(struct ksignal *ksig); 293 extern void signal_setup_done(int failed, struct ksignal *ksig, int stepping); 294 extern void exit_signals(struct task_struct *tsk); 295 extern void kernel_sigaction(int, __sighandler_t); 296 297 #define SIG_KTHREAD ((__force __sighandler_t)2) 298 #define SIG_KTHREAD_KERNEL ((__force __sighandler_t)3) 299 300 static inline void allow_signal(int sig) 301 { 302 /* 303 * Kernel threads handle their own signals. Let the signal code 304 * know it'll be handled, so that they don't get converted to 305 * SIGKILL or just silently dropped. 306 */ 307 kernel_sigaction(sig, SIG_KTHREAD); 308 } 309 310 static inline void allow_kernel_signal(int sig) 311 { 312 /* 313 * Kernel threads handle their own signals. Let the signal code 314 * know signals sent by the kernel will be handled, so that they 315 * don't get silently dropped. 316 */ 317 kernel_sigaction(sig, SIG_KTHREAD_KERNEL); 318 } 319 320 static inline void disallow_signal(int sig) 321 { 322 kernel_sigaction(sig, SIG_IGN); 323 } 324 325 extern struct kmem_cache *sighand_cachep; 326 327 extern bool unhandled_signal(struct task_struct *tsk, int sig); 328 329 /* 330 * In POSIX a signal is sent either to a specific thread (Linux task) 331 * or to the process as a whole (Linux thread group). How the signal 332 * is sent determines whether it's to one thread or the whole group, 333 * which determines which signal mask(s) are involved in blocking it 334 * from being delivered until later. When the signal is delivered, 335 * either it's caught or ignored by a user handler or it has a default 336 * effect that applies to the whole thread group (POSIX process). 337 * 338 * The possible effects an unblocked signal set to SIG_DFL can have are: 339 * ignore - Nothing Happens 340 * terminate - kill the process, i.e. all threads in the group, 341 * similar to exit_group. The group leader (only) reports 342 * WIFSIGNALED status to its parent. 343 * coredump - write a core dump file describing all threads using 344 * the same mm and then kill all those threads 345 * stop - stop all the threads in the group, i.e. TASK_STOPPED state 346 * 347 * SIGKILL and SIGSTOP cannot be caught, blocked, or ignored. 348 * Other signals when not blocked and set to SIG_DFL behaves as follows. 349 * The job control signals also have other special effects. 350 * 351 * +--------------------+------------------+ 352 * | POSIX signal | default action | 353 * +--------------------+------------------+ 354 * | SIGHUP | terminate | 355 * | SIGINT | terminate | 356 * | SIGQUIT | coredump | 357 * | SIGILL | coredump | 358 * | SIGTRAP | coredump | 359 * | SIGABRT/SIGIOT | coredump | 360 * | SIGBUS | coredump | 361 * | SIGFPE | coredump | 362 * | SIGKILL | terminate(+) | 363 * | SIGUSR1 | terminate | 364 * | SIGSEGV | coredump | 365 * | SIGUSR2 | terminate | 366 * | SIGPIPE | terminate | 367 * | SIGALRM | terminate | 368 * | SIGTERM | terminate | 369 * | SIGCHLD | ignore | 370 * | SIGCONT | ignore(*) | 371 * | SIGSTOP | stop(*)(+) | 372 * | SIGTSTP | stop(*) | 373 * | SIGTTIN | stop(*) | 374 * | SIGTTOU | stop(*) | 375 * | SIGURG | ignore | 376 * | SIGXCPU | coredump | 377 * | SIGXFSZ | coredump | 378 * | SIGVTALRM | terminate | 379 * | SIGPROF | terminate | 380 * | SIGPOLL/SIGIO | terminate | 381 * | SIGSYS/SIGUNUSED | coredump | 382 * | SIGSTKFLT | terminate | 383 * | SIGWINCH | ignore | 384 * | SIGPWR | terminate | 385 * | SIGRTMIN-SIGRTMAX | terminate | 386 * +--------------------+------------------+ 387 * | non-POSIX signal | default action | 388 * +--------------------+------------------+ 389 * | SIGEMT | coredump | 390 * +--------------------+------------------+ 391 * 392 * (+) For SIGKILL and SIGSTOP the action is "always", not just "default". 393 * (*) Special job control effects: 394 * When SIGCONT is sent, it resumes the process (all threads in the group) 395 * from TASK_STOPPED state and also clears any pending/queued stop signals 396 * (any of those marked with "stop(*)"). This happens regardless of blocking, 397 * catching, or ignoring SIGCONT. When any stop signal is sent, it clears 398 * any pending/queued SIGCONT signals; this happens regardless of blocking, 399 * catching, or ignored the stop signal, though (except for SIGSTOP) the 400 * default action of stopping the process may happen later or never. 401 */ 402 403 #ifdef SIGEMT 404 #define SIGEMT_MASK rt_sigmask(SIGEMT) 405 #else 406 #define SIGEMT_MASK 0 407 #endif 408 409 #if SIGRTMIN > BITS_PER_LONG 410 #define rt_sigmask(sig) (1ULL << ((sig)-1)) 411 #else 412 #define rt_sigmask(sig) sigmask(sig) 413 #endif 414 415 #define siginmask(sig, mask) \ 416 ((sig) > 0 && (sig) < SIGRTMIN && (rt_sigmask(sig) & (mask))) 417 418 #define SIG_KERNEL_ONLY_MASK (\ 419 rt_sigmask(SIGKILL) | rt_sigmask(SIGSTOP)) 420 421 #define SIG_KERNEL_STOP_MASK (\ 422 rt_sigmask(SIGSTOP) | rt_sigmask(SIGTSTP) | \ 423 rt_sigmask(SIGTTIN) | rt_sigmask(SIGTTOU) ) 424 425 #define SIG_KERNEL_COREDUMP_MASK (\ 426 rt_sigmask(SIGQUIT) | rt_sigmask(SIGILL) | \ 427 rt_sigmask(SIGTRAP) | rt_sigmask(SIGABRT) | \ 428 rt_sigmask(SIGFPE) | rt_sigmask(SIGSEGV) | \ 429 rt_sigmask(SIGBUS) | rt_sigmask(SIGSYS) | \ 430 rt_sigmask(SIGXCPU) | rt_sigmask(SIGXFSZ) | \ 431 SIGEMT_MASK ) 432 433 #define SIG_KERNEL_IGNORE_MASK (\ 434 rt_sigmask(SIGCONT) | rt_sigmask(SIGCHLD) | \ 435 rt_sigmask(SIGWINCH) | rt_sigmask(SIGURG) ) 436 437 #define SIG_SPECIFIC_SICODES_MASK (\ 438 rt_sigmask(SIGILL) | rt_sigmask(SIGFPE) | \ 439 rt_sigmask(SIGSEGV) | rt_sigmask(SIGBUS) | \ 440 rt_sigmask(SIGTRAP) | rt_sigmask(SIGCHLD) | \ 441 rt_sigmask(SIGPOLL) | rt_sigmask(SIGSYS) | \ 442 SIGEMT_MASK ) 443 444 #define sig_kernel_only(sig) siginmask(sig, SIG_KERNEL_ONLY_MASK) 445 #define sig_kernel_coredump(sig) siginmask(sig, SIG_KERNEL_COREDUMP_MASK) 446 #define sig_kernel_ignore(sig) siginmask(sig, SIG_KERNEL_IGNORE_MASK) 447 #define sig_kernel_stop(sig) siginmask(sig, SIG_KERNEL_STOP_MASK) 448 #define sig_specific_sicodes(sig) siginmask(sig, SIG_SPECIFIC_SICODES_MASK) 449 450 #define sig_fatal(t, signr) \ 451 (!siginmask(signr, SIG_KERNEL_IGNORE_MASK|SIG_KERNEL_STOP_MASK) && \ 452 (t)->sighand->action[(signr)-1].sa.sa_handler == SIG_DFL) 453 454 void signals_init(void); 455 456 int restore_altstack(const stack_t __user *); 457 int __save_altstack(stack_t __user *, unsigned long); 458 459 #define unsafe_save_altstack(uss, sp, label) do { \ 460 stack_t __user *__uss = uss; \ 461 struct task_struct *t = current; \ 462 unsafe_put_user((void __user *)t->sas_ss_sp, &__uss->ss_sp, label); \ 463 unsafe_put_user(t->sas_ss_flags, &__uss->ss_flags, label); \ 464 unsafe_put_user(t->sas_ss_size, &__uss->ss_size, label); \ 465 if (t->sas_ss_flags & SS_AUTODISARM) \ 466 sas_ss_reset(t); \ 467 } while (0); 468 469 #ifdef CONFIG_PROC_FS 470 struct seq_file; 471 extern void render_sigset_t(struct seq_file *, const char *, sigset_t *); 472 #endif 473 474 #ifndef arch_untagged_si_addr 475 /* 476 * Given a fault address and a signal and si_code which correspond to the 477 * _sigfault union member, returns the address that must appear in si_addr if 478 * the signal handler does not have SA_EXPOSE_TAGBITS enabled in sa_flags. 479 */ 480 static inline void __user *arch_untagged_si_addr(void __user *addr, 481 unsigned long sig, 482 unsigned long si_code) 483 { 484 return addr; 485 } 486 #endif 487 488 #endif /* _LINUX_SIGNAL_H */ 489