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_TRAPNO, 44 SIL_FAULT_MCEERR, 45 SIL_FAULT_BNDERR, 46 SIL_FAULT_PKUERR, 47 SIL_FAULT_PERF_EVENT, 48 SIL_CHLD, 49 SIL_RT, 50 SIL_SYS, 51 }; 52 53 enum siginfo_layout siginfo_layout(unsigned sig, int si_code); 54 55 /* 56 * Define some primitives to manipulate sigset_t. 57 */ 58 59 #ifndef __HAVE_ARCH_SIG_BITOPS 60 #include <linux/bitops.h> 61 62 /* We don't use <linux/bitops.h> for these because there is no need to 63 be atomic. */ 64 static inline void sigaddset(sigset_t *set, int _sig) 65 { 66 unsigned long sig = _sig - 1; 67 if (_NSIG_WORDS == 1) 68 set->sig[0] |= 1UL << sig; 69 else 70 set->sig[sig / _NSIG_BPW] |= 1UL << (sig % _NSIG_BPW); 71 } 72 73 static inline void sigdelset(sigset_t *set, int _sig) 74 { 75 unsigned long sig = _sig - 1; 76 if (_NSIG_WORDS == 1) 77 set->sig[0] &= ~(1UL << sig); 78 else 79 set->sig[sig / _NSIG_BPW] &= ~(1UL << (sig % _NSIG_BPW)); 80 } 81 82 static inline int sigismember(sigset_t *set, int _sig) 83 { 84 unsigned long sig = _sig - 1; 85 if (_NSIG_WORDS == 1) 86 return 1 & (set->sig[0] >> sig); 87 else 88 return 1 & (set->sig[sig / _NSIG_BPW] >> (sig % _NSIG_BPW)); 89 } 90 91 #endif /* __HAVE_ARCH_SIG_BITOPS */ 92 93 static inline int sigisemptyset(sigset_t *set) 94 { 95 switch (_NSIG_WORDS) { 96 case 4: 97 return (set->sig[3] | set->sig[2] | 98 set->sig[1] | set->sig[0]) == 0; 99 case 2: 100 return (set->sig[1] | set->sig[0]) == 0; 101 case 1: 102 return set->sig[0] == 0; 103 default: 104 BUILD_BUG(); 105 return 0; 106 } 107 } 108 109 static inline int sigequalsets(const sigset_t *set1, const sigset_t *set2) 110 { 111 switch (_NSIG_WORDS) { 112 case 4: 113 return (set1->sig[3] == set2->sig[3]) && 114 (set1->sig[2] == set2->sig[2]) && 115 (set1->sig[1] == set2->sig[1]) && 116 (set1->sig[0] == set2->sig[0]); 117 case 2: 118 return (set1->sig[1] == set2->sig[1]) && 119 (set1->sig[0] == set2->sig[0]); 120 case 1: 121 return set1->sig[0] == set2->sig[0]; 122 } 123 return 0; 124 } 125 126 #define sigmask(sig) (1UL << ((sig) - 1)) 127 128 #ifndef __HAVE_ARCH_SIG_SETOPS 129 #include <linux/string.h> 130 131 #define _SIG_SET_BINOP(name, op) \ 132 static inline void name(sigset_t *r, const sigset_t *a, const sigset_t *b) \ 133 { \ 134 unsigned long a0, a1, a2, a3, b0, b1, b2, b3; \ 135 \ 136 switch (_NSIG_WORDS) { \ 137 case 4: \ 138 a3 = a->sig[3]; a2 = a->sig[2]; \ 139 b3 = b->sig[3]; b2 = b->sig[2]; \ 140 r->sig[3] = op(a3, b3); \ 141 r->sig[2] = op(a2, b2); \ 142 fallthrough; \ 143 case 2: \ 144 a1 = a->sig[1]; b1 = b->sig[1]; \ 145 r->sig[1] = op(a1, b1); \ 146 fallthrough; \ 147 case 1: \ 148 a0 = a->sig[0]; b0 = b->sig[0]; \ 149 r->sig[0] = op(a0, b0); \ 150 break; \ 151 default: \ 152 BUILD_BUG(); \ 153 } \ 154 } 155 156 #define _sig_or(x,y) ((x) | (y)) 157 _SIG_SET_BINOP(sigorsets, _sig_or) 158 159 #define _sig_and(x,y) ((x) & (y)) 160 _SIG_SET_BINOP(sigandsets, _sig_and) 161 162 #define _sig_andn(x,y) ((x) & ~(y)) 163 _SIG_SET_BINOP(sigandnsets, _sig_andn) 164 165 #undef _SIG_SET_BINOP 166 #undef _sig_or 167 #undef _sig_and 168 #undef _sig_andn 169 170 #define _SIG_SET_OP(name, op) \ 171 static inline void name(sigset_t *set) \ 172 { \ 173 switch (_NSIG_WORDS) { \ 174 case 4: set->sig[3] = op(set->sig[3]); \ 175 set->sig[2] = op(set->sig[2]); \ 176 fallthrough; \ 177 case 2: set->sig[1] = op(set->sig[1]); \ 178 fallthrough; \ 179 case 1: set->sig[0] = op(set->sig[0]); \ 180 break; \ 181 default: \ 182 BUILD_BUG(); \ 183 } \ 184 } 185 186 #define _sig_not(x) (~(x)) 187 _SIG_SET_OP(signotset, _sig_not) 188 189 #undef _SIG_SET_OP 190 #undef _sig_not 191 192 static inline void sigemptyset(sigset_t *set) 193 { 194 switch (_NSIG_WORDS) { 195 default: 196 memset(set, 0, sizeof(sigset_t)); 197 break; 198 case 2: set->sig[1] = 0; 199 fallthrough; 200 case 1: set->sig[0] = 0; 201 break; 202 } 203 } 204 205 static inline void sigfillset(sigset_t *set) 206 { 207 switch (_NSIG_WORDS) { 208 default: 209 memset(set, -1, sizeof(sigset_t)); 210 break; 211 case 2: set->sig[1] = -1; 212 fallthrough; 213 case 1: set->sig[0] = -1; 214 break; 215 } 216 } 217 218 /* Some extensions for manipulating the low 32 signals in particular. */ 219 220 static inline void sigaddsetmask(sigset_t *set, unsigned long mask) 221 { 222 set->sig[0] |= mask; 223 } 224 225 static inline void sigdelsetmask(sigset_t *set, unsigned long mask) 226 { 227 set->sig[0] &= ~mask; 228 } 229 230 static inline int sigtestsetmask(sigset_t *set, unsigned long mask) 231 { 232 return (set->sig[0] & mask) != 0; 233 } 234 235 static inline void siginitset(sigset_t *set, unsigned long mask) 236 { 237 set->sig[0] = mask; 238 switch (_NSIG_WORDS) { 239 default: 240 memset(&set->sig[1], 0, sizeof(long)*(_NSIG_WORDS-1)); 241 break; 242 case 2: set->sig[1] = 0; 243 break; 244 case 1: ; 245 } 246 } 247 248 static inline void siginitsetinv(sigset_t *set, unsigned long mask) 249 { 250 set->sig[0] = ~mask; 251 switch (_NSIG_WORDS) { 252 default: 253 memset(&set->sig[1], -1, sizeof(long)*(_NSIG_WORDS-1)); 254 break; 255 case 2: set->sig[1] = -1; 256 break; 257 case 1: ; 258 } 259 } 260 261 #endif /* __HAVE_ARCH_SIG_SETOPS */ 262 263 static inline void init_sigpending(struct sigpending *sig) 264 { 265 sigemptyset(&sig->signal); 266 INIT_LIST_HEAD(&sig->list); 267 } 268 269 extern void flush_sigqueue(struct sigpending *queue); 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 } while (0); 466 467 #ifdef CONFIG_PROC_FS 468 struct seq_file; 469 extern void render_sigset_t(struct seq_file *, const char *, sigset_t *); 470 #endif 471 472 #ifndef arch_untagged_si_addr 473 /* 474 * Given a fault address and a signal and si_code which correspond to the 475 * _sigfault union member, returns the address that must appear in si_addr if 476 * the signal handler does not have SA_EXPOSE_TAGBITS enabled in sa_flags. 477 */ 478 static inline void __user *arch_untagged_si_addr(void __user *addr, 479 unsigned long sig, 480 unsigned long si_code) 481 { 482 return addr; 483 } 484 #endif 485 486 #endif /* _LINUX_SIGNAL_H */ 487