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 /*
  32  * Define some primitives to manipulate sigset_t.
  33  */
  34
  35 #ifndef __HAVE_ARCH_SIG_BITOPS
  36 #include <linux/bitops.h>
  37
  38 /* We don't use <linux/bitops.h> for these because there is no need to
  39    be atomic.  */
  40 static inline void sigaddset(sigset_t *set, int _sig)
  41 {
  42         unsigned long sig = _sig - 1;
  43         if (_NSIG_WORDS == 1)
  44                 set->sig[0] |= 1UL << sig;
  45         else
  46                 set->sig[sig / _NSIG_BPW] |= 1UL << (sig % _NSIG_BPW);
  47 }
  48
  49 static inline void sigdelset(sigset_t *set, int _sig)
  50 {
  51         unsigned long sig = _sig - 1;
  52         if (_NSIG_WORDS == 1)
  53                 set->sig[0] &= ~(1UL << sig);
  54         else
  55                 set->sig[sig / _NSIG_BPW] &= ~(1UL << (sig % _NSIG_BPW));
  56 }
  57
  58 static inline int sigismember(sigset_t *set, int _sig)
  59 {
  60         unsigned long sig = _sig - 1;
  61         if (_NSIG_WORDS == 1)
  62                 return 1 & (set->sig[0] >> sig);
  63         else
  64                 return 1 & (set->sig[sig / _NSIG_BPW] >> (sig % _NSIG_BPW));
  65 }
  66
  67 #endif /* __HAVE_ARCH_SIG_BITOPS */
  68
  69 static inline int sigisemptyset(sigset_t *set)
  70 {
  71         switch (_NSIG_WORDS) {
  72         case 4:
  73                 return (set->sig[3] | set->sig[2] |
  74                         set->sig[1] | set->sig[0]) == 0;
  75         case 2:
  76                 return (set->sig[1] | set->sig[0]) == 0;
  77         case 1:
  78                 return set->sig[0] == 0;
  79         default:
  80                 BUILD_BUG();
  81                 return 0;
  82         }
  83 }
  84
  85 #define sigmask(sig)    (1UL << ((sig) - 1))
  86
  87 #ifndef __HAVE_ARCH_SIG_SETOPS
  88 #include <linux/string.h>
  89
  90 #define _SIG_SET_BINOP(name, op)                                        \
  91 static inline void name(sigset_t *r, const sigset_t *a, const sigset_t *b) \
  92 {                                                                       \
  93         unsigned long a0, a1, a2, a3, b0, b1, b2, b3;                   \
  94                                                                         \
  95         switch (_NSIG_WORDS) {                                          \
  96         case 4:                                                         \
  97                 a3 = a->sig[3]; a2 = a->sig[2];                         \
  98                 b3 = b->sig[3]; b2 = b->sig[2];                         \
  99                 r->sig[3] = op(a3, b3);                                 \
 100                 r->sig[2] = op(a2, b2);                                 \
 101         case 2:                                                         \
 102                 a1 = a->sig[1]; b1 = b->sig[1];                         \
 103                 r->sig[1] = op(a1, b1);                                 \
 104         case 1:                                                         \
 105                 a0 = a->sig[0]; b0 = b->sig[0];                         \
 106                 r->sig[0] = op(a0, b0);                                 \
 107                 break;                                                  \
 108         default:                                                        \
 109                 BUILD_BUG();                                            \
 110         }                                                               \
 111 }
 112
 113 #define _sig_or(x,y)    ((x) | (y))
 114 _SIG_SET_BINOP(sigorsets, _sig_or)
 115
 116 #define _sig_and(x,y)   ((x) & (y))
 117 _SIG_SET_BINOP(sigandsets, _sig_and)
 118
 119 #define _sig_andn(x,y)  ((x) & ~(y))
 120 _SIG_SET_BINOP(sigandnsets, _sig_andn)
 121
 122 #undef _SIG_SET_BINOP
 123 #undef _sig_or
 124 #undef _sig_and
 125 #undef _sig_andn
 126
 127 #define _SIG_SET_OP(name, op)                                           \
 128 static inline void name(sigset_t *set)                                  \
 129 {                                                                       \
 130         switch (_NSIG_WORDS) {                                          \
 131         case 4: set->sig[3] = op(set->sig[3]);                          \
 132                 set->sig[2] = op(set->sig[2]);                          \
 133         case 2: set->sig[1] = op(set->sig[1]);                          \
 134         case 1: set->sig[0] = op(set->sig[0]);                          \
 135                     break;                                              \
 136         default:                                                        \
 137                 BUILD_BUG();                                            \
 138         }                                                               \
 139 }
 140
 141 #define _sig_not(x)     (~(x))
 142 _SIG_SET_OP(signotset, _sig_not)
 143
 144 #undef _SIG_SET_OP
 145 #undef _sig_not
 146
 147 static inline void sigemptyset(sigset_t *set)
 148 {
 149         switch (_NSIG_WORDS) {
 150         default:
 151                 memset(set, 0, sizeof(sigset_t));
 152                 break;
 153         case 2: set->sig[1] = 0;
 154         case 1: set->sig[0] = 0;
 155                 break;
 156         }
 157 }
 158
 159 static inline void sigfillset(sigset_t *set)
 160 {
 161         switch (_NSIG_WORDS) {
 162         default:
 163                 memset(set, -1, sizeof(sigset_t));
 164                 break;
 165         case 2: set->sig[1] = -1;
 166         case 1: set->sig[0] = -1;
 167                 break;
 168         }
 169 }
 170
 171 /* Some extensions for manipulating the low 32 signals in particular.  */
 172
 173 static inline void sigaddsetmask(sigset_t *set, unsigned long mask)
 174 {
 175         set->sig[0] |= mask;
 176 }
 177
 178 static inline void sigdelsetmask(sigset_t *set, unsigned long mask)
 179 {
 180         set->sig[0] &= ~mask;
 181 }
 182
 183 static inline int sigtestsetmask(sigset_t *set, unsigned long mask)
 184 {
 185         return (set->sig[0] & mask) != 0;
 186 }
 187
 188 static inline void siginitset(sigset_t *set, unsigned long mask)
 189 {
 190         set->sig[0] = mask;
 191         switch (_NSIG_WORDS) {
 192         default:
 193                 memset(&set->sig[1], 0, sizeof(long)*(_NSIG_WORDS-1));
 194                 break;
 195         case 2: set->sig[1] = 0;
 196         case 1: ;
 197         }
 198 }
 199
 200 static inline void siginitsetinv(sigset_t *set, unsigned long mask)
 201 {
 202         set->sig[0] = ~mask;
 203         switch (_NSIG_WORDS) {
 204         default:
 205                 memset(&set->sig[1], -1, sizeof(long)*(_NSIG_WORDS-1));
 206                 break;
 207         case 2: set->sig[1] = -1;
 208         case 1: ;
 209         }
 210 }
 211
 212 #endif /* __HAVE_ARCH_SIG_SETOPS */
 213
 214 static inline void init_sigpending(struct sigpending *sig)
 215 {
 216         sigemptyset(&sig->signal);
 217         INIT_LIST_HEAD(&sig->list);
 218 }
 219
 220 extern void flush_sigqueue(struct sigpending *queue);
 221
 222 /* Test if 'sig' is valid signal. Use this instead of testing _NSIG directly */
 223 static inline int valid_signal(unsigned long sig)
 224 {
 225         return sig <= _NSIG ? 1 : 0;
 226 }
 227
 228 struct timespec;
 229 struct pt_regs;
 230
 231 extern int next_signal(struct sigpending *pending, sigset_t *mask);
 232 extern int do_send_sig_info(int sig, struct siginfo *info,
 233                                 struct task_struct *p, bool group);
 234 extern int group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p);
 235 extern int __group_send_sig_info(int, struct siginfo *, struct task_struct *);
 236 extern int do_sigtimedwait(const sigset_t *, siginfo_t *,
 237                                 const struct timespec *);
 238 extern int sigprocmask(int, sigset_t *, sigset_t *);
 239 extern void set_current_blocked(sigset_t *);
 240 extern void __set_current_blocked(const sigset_t *);
 241 extern int show_unhandled_signals;
 242 extern int sigsuspend(sigset_t *);
 243
 244 struct sigaction {
 245 #ifndef __ARCH_HAS_IRIX_SIGACTION
 246         __sighandler_t  sa_handler;
 247         unsigned long   sa_flags;
 248 #else
 249         unsigned int    sa_flags;
 250         __sighandler_t  sa_handler;
 251 #endif
 252 #ifdef __ARCH_HAS_SA_RESTORER
 253         __sigrestore_t sa_restorer;
 254 #endif
 255         sigset_t        sa_mask;        /* mask last for extensibility */
 256 };
 257
 258 struct k_sigaction {
 259         struct sigaction sa;
 260 #ifdef __ARCH_HAS_KA_RESTORER
 261         __sigrestore_t ka_restorer;
 262 #endif
 263 };
 264
 265 #ifdef CONFIG_OLD_SIGACTION
 266 struct old_sigaction {
 267         __sighandler_t sa_handler;
 268         old_sigset_t sa_mask;
 269         unsigned long sa_flags;
 270         __sigrestore_t sa_restorer;
 271 };
 272 #endif
 273
 274 struct ksignal {
 275         struct k_sigaction ka;
 276         siginfo_t info;
 277         int sig;
 278 };
 279
 280 extern int 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 static inline void allow_signal(int sig)
 286 {
 287         /*
 288          * Kernel threads handle their own signals. Let the signal code
 289          * know it'll be handled, so that they don't get converted to
 290          * SIGKILL or just silently dropped.
 291          */
 292         kernel_sigaction(sig, (__force __sighandler_t)2);
 293 }
 294
 295 static inline void disallow_signal(int sig)
 296 {
 297         kernel_sigaction(sig, SIG_IGN);
 298 }
 299
 300 extern struct kmem_cache *sighand_cachep;
 301
 302 int unhandled_signal(struct task_struct *tsk, int sig);
 303
 304 /*
 305  * In POSIX a signal is sent either to a specific thread (Linux task)
 306  * or to the process as a whole (Linux thread group).  How the signal
 307  * is sent determines whether it's to one thread or the whole group,
 308  * which determines which signal mask(s) are involved in blocking it
 309  * from being delivered until later.  When the signal is delivered,
 310  * either it's caught or ignored by a user handler or it has a default
 311  * effect that applies to the whole thread group (POSIX process).
 312  *
 313  * The possible effects an unblocked signal set to SIG_DFL can have are:
 314  *   ignore     - Nothing Happens
 315  *   terminate  - kill the process, i.e. all threads in the group,
 316  *                similar to exit_group.  The group leader (only) reports
 317  *                WIFSIGNALED status to its parent.
 318  *   coredump   - write a core dump file describing all threads using
 319  *                the same mm and then kill all those threads
 320  *   stop       - stop all the threads in the group, i.e. TASK_STOPPED state
 321  *
 322  * SIGKILL and SIGSTOP cannot be caught, blocked, or ignored.
 323  * Other signals when not blocked and set to SIG_DFL behaves as follows.
 324  * The job control signals also have other special effects.
 325  *
 326  *      +--------------------+------------------+
 327  *      |  POSIX signal      |  default action  |
 328  *      +--------------------+------------------+
 329  *      |  SIGHUP            |  terminate       |
 330  *      |  SIGINT            |  terminate       |
 331  *      |  SIGQUIT           |  coredump        |
 332  *      |  SIGILL            |  coredump        |
 333  *      |  SIGTRAP           |  coredump        |
 334  *      |  SIGABRT/SIGIOT    |  coredump        |
 335  *      |  SIGBUS            |  coredump        |
 336  *      |  SIGFPE            |  coredump        |
 337  *      |  SIGKILL           |  terminate(+)    |
 338  *      |  SIGUSR1           |  terminate       |
 339  *      |  SIGSEGV           |  coredump        |
 340  *      |  SIGUSR2           |  terminate       |
 341  *      |  SIGPIPE           |  terminate       |
 342  *      |  SIGALRM           |  terminate       |
 343  *      |  SIGTERM           |  terminate       |
 344  *      |  SIGCHLD           |  ignore          |
 345  *      |  SIGCONT           |  ignore(*)       |
 346  *      |  SIGSTOP           |  stop(*)(+)      |
 347  *      |  SIGTSTP           |  stop(*)         |
 348  *      |  SIGTTIN           |  stop(*)         |
 349  *      |  SIGTTOU           |  stop(*)         |
 350  *      |  SIGURG            |  ignore          |
 351  *      |  SIGXCPU           |  coredump        |
 352  *      |  SIGXFSZ           |  coredump        |
 353  *      |  SIGVTALRM         |  terminate       |
 354  *      |  SIGPROF           |  terminate       |
 355  *      |  SIGPOLL/SIGIO     |  terminate       |
 356  *      |  SIGSYS/SIGUNUSED  |  coredump        |
 357  *      |  SIGSTKFLT         |  terminate       |
 358  *      |  SIGWINCH          |  ignore          |
 359  *      |  SIGPWR            |  terminate       |
 360  *      |  SIGRTMIN-SIGRTMAX |  terminate       |
 361  *      +--------------------+------------------+
 362  *      |  non-POSIX signal  |  default action  |
 363  *      +--------------------+------------------+
 364  *      |  SIGEMT            |  coredump        |
 365  *      +--------------------+------------------+
 366  *
 367  * (+) For SIGKILL and SIGSTOP the action is "always", not just "default".
 368  * (*) Special job control effects:
 369  * When SIGCONT is sent, it resumes the process (all threads in the group)
 370  * from TASK_STOPPED state and also clears any pending/queued stop signals
 371  * (any of those marked with "stop(*)").  This happens regardless of blocking,
 372  * catching, or ignoring SIGCONT.  When any stop signal is sent, it clears
 373  * any pending/queued SIGCONT signals; this happens regardless of blocking,
 374  * catching, or ignored the stop signal, though (except for SIGSTOP) the
 375  * default action of stopping the process may happen later or never.
 376  */
 377
 378 #ifdef SIGEMT
 379 #define SIGEMT_MASK     rt_sigmask(SIGEMT)
 380 #else
 381 #define SIGEMT_MASK     0
 382 #endif
 383
 384 #if SIGRTMIN > BITS_PER_LONG
 385 #define rt_sigmask(sig) (1ULL << ((sig)-1))
 386 #else
 387 #define rt_sigmask(sig) sigmask(sig)
 388 #endif
 389 #define siginmask(sig, mask) (rt_sigmask(sig) & (mask))
 390
 391 #define SIG_KERNEL_ONLY_MASK (\
 392         rt_sigmask(SIGKILL)   |  rt_sigmask(SIGSTOP))
 393
 394 #define SIG_KERNEL_STOP_MASK (\
 395         rt_sigmask(SIGSTOP)   |  rt_sigmask(SIGTSTP)   | \
 396         rt_sigmask(SIGTTIN)   |  rt_sigmask(SIGTTOU)   )
 397
 398 #define SIG_KERNEL_COREDUMP_MASK (\
 399         rt_sigmask(SIGQUIT)   |  rt_sigmask(SIGILL)    | \
 400         rt_sigmask(SIGTRAP)   |  rt_sigmask(SIGABRT)   | \
 401         rt_sigmask(SIGFPE)    |  rt_sigmask(SIGSEGV)   | \
 402         rt_sigmask(SIGBUS)    |  rt_sigmask(SIGSYS)    | \
 403         rt_sigmask(SIGXCPU)   |  rt_sigmask(SIGXFSZ)   | \
 404         SIGEMT_MASK                                    )
 405
 406 #define SIG_KERNEL_IGNORE_MASK (\
 407         rt_sigmask(SIGCONT)   |  rt_sigmask(SIGCHLD)   | \
 408         rt_sigmask(SIGWINCH)  |  rt_sigmask(SIGURG)    )
 409
 410 #define sig_kernel_only(sig) \
 411         (((sig) < SIGRTMIN) && siginmask(sig, SIG_KERNEL_ONLY_MASK))
 412 #define sig_kernel_coredump(sig) \
 413         (((sig) < SIGRTMIN) && siginmask(sig, SIG_KERNEL_COREDUMP_MASK))
 414 #define sig_kernel_ignore(sig) \
 415         (((sig) < SIGRTMIN) && siginmask(sig, SIG_KERNEL_IGNORE_MASK))
 416 #define sig_kernel_stop(sig) \
 417         (((sig) < SIGRTMIN) && siginmask(sig, SIG_KERNEL_STOP_MASK))
 418
 419 #define sig_user_defined(t, signr) \
 420         (((t)->sighand->action[(signr)-1].sa.sa_handler != SIG_DFL) &&  \
 421          ((t)->sighand->action[(signr)-1].sa.sa_handler != SIG_IGN))
 422
 423 #define sig_fatal(t, signr) \
 424         (!siginmask(signr, SIG_KERNEL_IGNORE_MASK|SIG_KERNEL_STOP_MASK) && \
 425          (t)->sighand->action[(signr)-1].sa.sa_handler == SIG_DFL)
 426
 427 void signals_init(void);
 428
 429 int restore_altstack(const stack_t __user *);
 430 int __save_altstack(stack_t __user *, unsigned long);
 431
 432 #define save_altstack_ex(uss, sp) do { \
 433         stack_t __user *__uss = uss; \
 434         struct task_struct *t = current; \
 435         put_user_ex((void __user *)t->sas_ss_sp, &__uss->ss_sp); \
 436         put_user_ex(sas_ss_flags(sp), &__uss->ss_flags); \
 437         put_user_ex(t->sas_ss_size, &__uss->ss_size); \
 438 } while (0);
 439
 440 #ifdef CONFIG_PROC_FS
 441 struct seq_file;
 442 extern void render_sigset_t(struct seq_file *, const char *, sigset_t *);
 443 #endif
 444
 445 #endif /* _LINUX_SIGNAL_H */