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