include/linux/signal.h

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