include/linux/signal.h

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