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