include/linux/signal.h

   1 #ifndef _LINUX_SIGNAL_H
   2 #define _LINUX_SIGNAL_H
   3
   4 #include <linux/list.h>
   5 #include <uapi/linux/signal.h>
   6
   7 struct task_struct;
   8
   9 /* for sysctl */
  10 extern int print_fatal_signals;
  11 /*
  12  * Real Time signals may be queued.
  13  */
  14
  15 struct sigqueue {
  16         struct list_head list;
  17         int flags;
  18         siginfo_t info;
  19         struct user_struct *user;
  20 };
  21
  22 /* flags values. */
  23 #define SIGQUEUE_PREALLOC       1
  24
  25 struct sigpending {
  26         struct list_head list;
  27         sigset_t signal;
  28 };
  29
  30 /*
  31  * Define some primitives to manipulate sigset_t.
  32  */
  33
  34 #ifndef __HAVE_ARCH_SIG_BITOPS
  35 #include <linux/bitops.h>
  36
  37 /* We don't use <linux/bitops.h> for these because there is no need to
  38    be atomic.  */
  39 static inline void sigaddset(sigset_t *set, int _sig)
  40 {
  41         unsigned long sig = _sig - 1;
  42         if (_NSIG_WORDS == 1)
  43                 set->sig[0] |= 1UL << sig;
  44         else
  45                 set->sig[sig / _NSIG_BPW] |= 1UL << (sig % _NSIG_BPW);
  46 }
  47
  48 static inline void sigdelset(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 int sigismember(sigset_t *set, int _sig)
  58 {
  59         unsigned long sig = _sig - 1;
  60         if (_NSIG_WORDS == 1)
  61                 return 1 & (set->sig[0] >> sig);
  62         else
  63                 return 1 & (set->sig[sig / _NSIG_BPW] >> (sig % _NSIG_BPW));
  64 }
  65
  66 #endif /* __HAVE_ARCH_SIG_BITOPS */
  67
  68 static inline int sigisemptyset(sigset_t *set)
  69 {
  70         extern void _NSIG_WORDS_is_unsupported_size(void);
  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                 _NSIG_WORDS_is_unsupported_size();
  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         extern void _NSIG_WORDS_is_unsupported_size(void);              \
  94         unsigned long a0, a1, a2, a3, b0, b1, b2, b3;                   \
  95                                                                         \
  96         switch (_NSIG_WORDS) {                                          \
  97             case 4:                                                     \
  98                 a3 = a->sig[3]; a2 = a->sig[2];                         \
  99                 b3 = b->sig[3]; b2 = b->sig[2];                         \
 100                 r->sig[3] = op(a3, b3);                                 \
 101                 r->sig[2] = op(a2, b2);                                 \
 102             case 2:                                                     \
 103                 a1 = a->sig[1]; b1 = b->sig[1];                         \
 104                 r->sig[1] = op(a1, b1);                                 \
 105             case 1:                                                     \
 106                 a0 = a->sig[0]; b0 = b->sig[0];                         \
 107                 r->sig[0] = op(a0, b0);                                 \
 108                 break;                                                  \
 109             default:                                                    \
 110                 _NSIG_WORDS_is_unsupported_size();                      \
 111         }                                                               \
 112 }
 113
 114 #define _sig_or(x,y)    ((x) | (y))
 115 _SIG_SET_BINOP(sigorsets, _sig_or)
 116
 117 #define _sig_and(x,y)   ((x) & (y))
 118 _SIG_SET_BINOP(sigandsets, _sig_and)
 119
 120 #define _sig_andn(x,y)  ((x) & ~(y))
 121 _SIG_SET_BINOP(sigandnsets, _sig_andn)
 122
 123 #undef _SIG_SET_BINOP
 124 #undef _sig_or
 125 #undef _sig_and
 126 #undef _sig_andn
 127
 128 #define _SIG_SET_OP(name, op)                                           \
 129 static inline void name(sigset_t *set)                                  \
 130 {                                                                       \
 131         extern void _NSIG_WORDS_is_unsupported_size(void);              \
 132                                                                         \
 133         switch (_NSIG_WORDS) {                                          \
 134             case 4: set->sig[3] = op(set->sig[3]);                      \
 135                     set->sig[2] = op(set->sig[2]);                      \
 136             case 2: set->sig[1] = op(set->sig[1]);                      \
 137             case 1: set->sig[0] = op(set->sig[0]);                      \
 138                     break;                                              \
 139             default:                                                    \
 140                 _NSIG_WORDS_is_unsupported_size();                      \
 141         }                                                               \
 142 }
 143
 144 #define _sig_not(x)     (~(x))
 145 _SIG_SET_OP(signotset, _sig_not)
 146
 147 #undef _SIG_SET_OP
 148 #undef _sig_not
 149
 150 static inline void sigemptyset(sigset_t *set)
 151 {
 152         switch (_NSIG_WORDS) {
 153         default:
 154                 memset(set, 0, sizeof(sigset_t));
 155                 break;
 156         case 2: set->sig[1] = 0;
 157         case 1: set->sig[0] = 0;
 158                 break;
 159         }
 160 }
 161
 162 static inline void sigfillset(sigset_t *set)
 163 {
 164         switch (_NSIG_WORDS) {
 165         default:
 166                 memset(set, -1, sizeof(sigset_t));
 167                 break;
 168         case 2: set->sig[1] = -1;
 169         case 1: set->sig[0] = -1;
 170                 break;
 171         }
 172 }
 173
 174 /* Some extensions for manipulating the low 32 signals in particular.  */
 175
 176 static inline void sigaddsetmask(sigset_t *set, unsigned long mask)
 177 {
 178         set->sig[0] |= mask;
 179 }
 180
 181 static inline void sigdelsetmask(sigset_t *set, unsigned long mask)
 182 {
 183         set->sig[0] &= ~mask;
 184 }
 185
 186 static inline int sigtestsetmask(sigset_t *set, unsigned long mask)
 187 {
 188         return (set->sig[0] & mask) != 0;
 189 }
 190
 191 static inline void siginitset(sigset_t *set, unsigned long mask)
 192 {
 193         set->sig[0] = mask;
 194         switch (_NSIG_WORDS) {
 195         default:
 196                 memset(&set->sig[1], 0, sizeof(long)*(_NSIG_WORDS-1));
 197                 break;
 198         case 2: set->sig[1] = 0;
 199         case 1: ;
 200         }
 201 }
 202
 203 static inline void siginitsetinv(sigset_t *set, unsigned long mask)
 204 {
 205         set->sig[0] = ~mask;
 206         switch (_NSIG_WORDS) {
 207         default:
 208                 memset(&set->sig[1], -1, sizeof(long)*(_NSIG_WORDS-1));
 209                 break;
 210         case 2: set->sig[1] = -1;
 211         case 1: ;
 212         }
 213 }
 214
 215 #endif /* __HAVE_ARCH_SIG_SETOPS */
 216
 217 static inline void init_sigpending(struct sigpending *sig)
 218 {
 219         sigemptyset(&sig->signal);
 220         INIT_LIST_HEAD(&sig->list);
 221 }
 222
 223 extern void flush_sigqueue(struct sigpending *queue);
 224
 225 /* Test if 'sig' is valid signal. Use this instead of testing _NSIG directly */
 226 static inline int valid_signal(unsigned long sig)
 227 {
 228         return sig <= _NSIG ? 1 : 0;
 229 }
 230
 231 struct timespec;
 232 struct pt_regs;
 233
 234 extern int next_signal(struct sigpending *pending, sigset_t *mask);
 235 extern int do_send_sig_info(int sig, struct siginfo *info,
 236                                 struct task_struct *p, bool group);
 237 extern int group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p);
 238 extern int __group_send_sig_info(int, struct siginfo *, struct task_struct *);
 239 extern int do_sigtimedwait(const sigset_t *, siginfo_t *,
 240                                 const struct timespec *);
 241 extern int sigprocmask(int, sigset_t *, sigset_t *);
 242 extern void set_current_blocked(sigset_t *);
 243 extern void __set_current_blocked(const sigset_t *);
 244 extern int show_unhandled_signals;
 245 extern int sigsuspend(sigset_t *);
 246
 247 struct sigaction {
 248 #ifndef __ARCH_HAS_IRIX_SIGACTION
 249         __sighandler_t  sa_handler;
 250         unsigned long   sa_flags;
 251 #else
 252         unsigned int    sa_flags;
 253         __sighandler_t  sa_handler;
 254 #endif
 255 #ifdef __ARCH_HAS_SA_RESTORER
 256         __sigrestore_t sa_restorer;
 257 #endif
 258         sigset_t        sa_mask;        /* mask last for extensibility */
 259 };
 260
 261 struct k_sigaction {
 262         struct sigaction sa;
 263 #ifdef __ARCH_HAS_KA_RESTORER
 264         __sigrestore_t ka_restorer;
 265 #endif
 266 };
 267
 268 #ifdef CONFIG_OLD_SIGACTION
 269 struct old_sigaction {
 270         __sighandler_t sa_handler;
 271         old_sigset_t sa_mask;
 272         unsigned long sa_flags;
 273         __sigrestore_t sa_restorer;
 274 };
 275 #endif
 276
 277 struct ksignal {
 278         struct k_sigaction ka;
 279         siginfo_t info;
 280         int sig;
 281 };
 282
 283 extern int get_signal(struct ksignal *ksig);
 284 extern void signal_setup_done(int failed, struct ksignal *ksig, int stepping);
 285 extern void exit_signals(struct task_struct *tsk);
 286 extern void kernel_sigaction(int, __sighandler_t);
 287
 288 static inline void allow_signal(int sig)
 289 {
 290         /*
 291          * Kernel threads handle their own signals. Let the signal code
 292          * know it'll be handled, so that they don't get converted to
 293          * SIGKILL or just silently dropped.
 294          */
 295         kernel_sigaction(sig, (__force __sighandler_t)2);
 296 }
 297
 298 static inline void disallow_signal(int sig)
 299 {
 300         kernel_sigaction(sig, SIG_IGN);
 301 }
 302
 303 extern struct kmem_cache *sighand_cachep;
 304
 305 int unhandled_signal(struct task_struct *tsk, int sig);
 306
 307 /*
 308  * In POSIX a signal is sent either to a specific thread (Linux task)
 309  * or to the process as a whole (Linux thread group).  How the signal
 310  * is sent determines whether it's to one thread or the whole group,
 311  * which determines which signal mask(s) are involved in blocking it
 312  * from being delivered until later.  When the signal is delivered,
 313  * either it's caught or ignored by a user handler or it has a default
 314  * effect that applies to the whole thread group (POSIX process).
 315  *
 316  * The possible effects an unblocked signal set to SIG_DFL can have are:
 317  *   ignore     - Nothing Happens
 318  *   terminate  - kill the process, i.e. all threads in the group,
 319  *                similar to exit_group.  The group leader (only) reports
 320  *                WIFSIGNALED status to its parent.
 321  *   coredump   - write a core dump file describing all threads using
 322  *                the same mm and then kill all those threads
 323  *   stop       - stop all the threads in the group, i.e. TASK_STOPPED state
 324  *
 325  * SIGKILL and SIGSTOP cannot be caught, blocked, or ignored.
 326  * Other signals when not blocked and set to SIG_DFL behaves as follows.
 327  * The job control signals also have other special effects.
 328  *
 329  *      +--------------------+------------------+
 330  *      |  POSIX signal      |  default action  |
 331  *      +--------------------+------------------+
 332  *      |  SIGHUP            |  terminate       |
 333  *      |  SIGINT            |  terminate       |
 334  *      |  SIGQUIT           |  coredump        |
 335  *      |  SIGILL            |  coredump        |
 336  *      |  SIGTRAP           |  coredump        |
 337  *      |  SIGABRT/SIGIOT    |  coredump        |
 338  *      |  SIGBUS            |  coredump        |
 339  *      |  SIGFPE            |  coredump        |
 340  *      |  SIGKILL           |  terminate(+)    |
 341  *      |  SIGUSR1           |  terminate       |
 342  *      |  SIGSEGV           |  coredump        |
 343  *      |  SIGUSR2           |  terminate       |
 344  *      |  SIGPIPE           |  terminate       |
 345  *      |  SIGALRM           |  terminate       |
 346  *      |  SIGTERM           |  terminate       |
 347  *      |  SIGCHLD           |  ignore          |
 348  *      |  SIGCONT           |  ignore(*)       |
 349  *      |  SIGSTOP           |  stop(*)(+)      |
 350  *      |  SIGTSTP           |  stop(*)         |
 351  *      |  SIGTTIN           |  stop(*)         |
 352  *      |  SIGTTOU           |  stop(*)         |
 353  *      |  SIGURG            |  ignore          |
 354  *      |  SIGXCPU           |  coredump        |
 355  *      |  SIGXFSZ           |  coredump        |
 356  *      |  SIGVTALRM         |  terminate       |
 357  *      |  SIGPROF           |  terminate       |
 358  *      |  SIGPOLL/SIGIO     |  terminate       |
 359  *      |  SIGSYS/SIGUNUSED  |  coredump        |
 360  *      |  SIGSTKFLT         |  terminate       |
 361  *      |  SIGWINCH          |  ignore          |
 362  *      |  SIGPWR            |  terminate       |
 363  *      |  SIGRTMIN-SIGRTMAX |  terminate       |
 364  *      +--------------------+------------------+
 365  *      |  non-POSIX signal  |  default action  |
 366  *      +--------------------+------------------+
 367  *      |  SIGEMT            |  coredump        |
 368  *      +--------------------+------------------+
 369  *
 370  * (+) For SIGKILL and SIGSTOP the action is "always", not just "default".
 371  * (*) Special job control effects:
 372  * When SIGCONT is sent, it resumes the process (all threads in the group)
 373  * from TASK_STOPPED state and also clears any pending/queued stop signals
 374  * (any of those marked with "stop(*)").  This happens regardless of blocking,
 375  * catching, or ignoring SIGCONT.  When any stop signal is sent, it clears
 376  * any pending/queued SIGCONT signals; this happens regardless of blocking,
 377  * catching, or ignored the stop signal, though (except for SIGSTOP) the
 378  * default action of stopping the process may happen later or never.
 379  */
 380
 381 #ifdef SIGEMT
 382 #define SIGEMT_MASK     rt_sigmask(SIGEMT)
 383 #else
 384 #define SIGEMT_MASK     0
 385 #endif
 386
 387 #if SIGRTMIN > BITS_PER_LONG
 388 #define rt_sigmask(sig) (1ULL << ((sig)-1))
 389 #else
 390 #define rt_sigmask(sig) sigmask(sig)
 391 #endif
 392 #define siginmask(sig, mask) (rt_sigmask(sig) & (mask))
 393
 394 #define SIG_KERNEL_ONLY_MASK (\
 395         rt_sigmask(SIGKILL)   |  rt_sigmask(SIGSTOP))
 396
 397 #define SIG_KERNEL_STOP_MASK (\
 398         rt_sigmask(SIGSTOP)   |  rt_sigmask(SIGTSTP)   | \
 399         rt_sigmask(SIGTTIN)   |  rt_sigmask(SIGTTOU)   )
 400
 401 #define SIG_KERNEL_COREDUMP_MASK (\
 402         rt_sigmask(SIGQUIT)   |  rt_sigmask(SIGILL)    | \
 403         rt_sigmask(SIGTRAP)   |  rt_sigmask(SIGABRT)   | \
 404         rt_sigmask(SIGFPE)    |  rt_sigmask(SIGSEGV)   | \
 405         rt_sigmask(SIGBUS)    |  rt_sigmask(SIGSYS)    | \
 406         rt_sigmask(SIGXCPU)   |  rt_sigmask(SIGXFSZ)   | \
 407         SIGEMT_MASK                                    )
 408
 409 #define SIG_KERNEL_IGNORE_MASK (\
 410         rt_sigmask(SIGCONT)   |  rt_sigmask(SIGCHLD)   | \
 411         rt_sigmask(SIGWINCH)  |  rt_sigmask(SIGURG)    )
 412
 413 #define sig_kernel_only(sig) \
 414         (((sig) < SIGRTMIN) && siginmask(sig, SIG_KERNEL_ONLY_MASK))
 415 #define sig_kernel_coredump(sig) \
 416         (((sig) < SIGRTMIN) && siginmask(sig, SIG_KERNEL_COREDUMP_MASK))
 417 #define sig_kernel_ignore(sig) \
 418         (((sig) < SIGRTMIN) && siginmask(sig, SIG_KERNEL_IGNORE_MASK))
 419 #define sig_kernel_stop(sig) \
 420         (((sig) < SIGRTMIN) && siginmask(sig, SIG_KERNEL_STOP_MASK))
 421
 422 #define sig_user_defined(t, signr) \
 423         (((t)->sighand->action[(signr)-1].sa.sa_handler != SIG_DFL) &&  \
 424          ((t)->sighand->action[(signr)-1].sa.sa_handler != SIG_IGN))
 425
 426 #define sig_fatal(t, signr) \
 427         (!siginmask(signr, SIG_KERNEL_IGNORE_MASK|SIG_KERNEL_STOP_MASK) && \
 428          (t)->sighand->action[(signr)-1].sa.sa_handler == SIG_DFL)
 429
 430 void signals_init(void);
 431
 432 int restore_altstack(const stack_t __user *);
 433 int __save_altstack(stack_t __user *, unsigned long);
 434
 435 #define save_altstack_ex(uss, sp) do { \
 436         stack_t __user *__uss = uss; \
 437         struct task_struct *t = current; \
 438         put_user_ex((void __user *)t->sas_ss_sp, &__uss->ss_sp); \
 439         put_user_ex(sas_ss_flags(sp), &__uss->ss_flags); \
 440         put_user_ex(t->sas_ss_size, &__uss->ss_size); \
 441 } while (0);
 442
 443 #ifdef CONFIG_PROC_FS
 444 struct seq_file;
 445 extern void render_sigset_t(struct seq_file *, const char *, sigset_t *);
 446 #endif
 447
 448 #endif /* _LINUX_SIGNAL_H */