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