include/linux/signal.h

   1 #ifndef _LINUX_SIGNAL_H
   2 #define _LINUX_SIGNAL_H
   3
   4 #include <linux/bug.h>
   5 #include <linux/signal_types.h>
   6
   7 struct task_struct;
   8
   9 /* for sysctl */
  10 extern int print_fatal_signals;
  11
  12 #ifndef HAVE_ARCH_COPY_SIGINFO
  13
  14 #include <linux/string.h>
  15
  16 static inline void copy_siginfo(struct siginfo *to, struct siginfo *from)
  17 {
  18         if (from->si_code < 0)
  19                 memcpy(to, from, sizeof(*to));
  20         else
  21                 /* _sigchld is currently the largest know union member */
  22                 memcpy(to, from, __ARCH_SI_PREAMBLE_SIZE + sizeof(from->_sifields._sigchld));
  23 }
  24
  25 #endif
  26
  27 /*
  28  * Define some primitives to manipulate sigset_t.
  29  */
  30
  31 #ifndef __HAVE_ARCH_SIG_BITOPS
  32 #include <linux/bitops.h>
  33
  34 /* We don't use <linux/bitops.h> for these because there is no need to
  35    be atomic.  */
  36 static inline void sigaddset(sigset_t *set, int _sig)
  37 {
  38         unsigned long sig = _sig - 1;
  39         if (_NSIG_WORDS == 1)
  40                 set->sig[0] |= 1UL << sig;
  41         else
  42                 set->sig[sig / _NSIG_BPW] |= 1UL << (sig % _NSIG_BPW);
  43 }
  44
  45 static inline void sigdelset(sigset_t *set, int _sig)
  46 {
  47         unsigned long sig = _sig - 1;
  48         if (_NSIG_WORDS == 1)
  49                 set->sig[0] &= ~(1UL << sig);
  50         else
  51                 set->sig[sig / _NSIG_BPW] &= ~(1UL << (sig % _NSIG_BPW));
  52 }
  53
  54 static inline int sigismember(sigset_t *set, int _sig)
  55 {
  56         unsigned long sig = _sig - 1;
  57         if (_NSIG_WORDS == 1)
  58                 return 1 & (set->sig[0] >> sig);
  59         else
  60                 return 1 & (set->sig[sig / _NSIG_BPW] >> (sig % _NSIG_BPW));
  61 }
  62
  63 #endif /* __HAVE_ARCH_SIG_BITOPS */
  64
  65 static inline int sigisemptyset(sigset_t *set)
  66 {
  67         switch (_NSIG_WORDS) {
  68         case 4:
  69                 return (set->sig[3] | set->sig[2] |
  70                         set->sig[1] | set->sig[0]) == 0;
  71         case 2:
  72                 return (set->sig[1] | set->sig[0]) == 0;
  73         case 1:
  74                 return set->sig[0] == 0;
  75         default:
  76                 BUILD_BUG();
  77                 return 0;
  78         }
  79 }
  80
  81 static inline int sigequalsets(const sigset_t *set1, const sigset_t *set2)
  82 {
  83         switch (_NSIG_WORDS) {
  84         case 4:
  85                 return  (set1->sig[3] == set2->sig[3]) &&
  86                         (set1->sig[2] == set2->sig[2]) &&
  87                         (set1->sig[1] == set2->sig[1]) &&
  88                         (set1->sig[0] == set2->sig[0]);
  89         case 2:
  90                 return  (set1->sig[1] == set2->sig[1]) &&
  91                         (set1->sig[0] == set2->sig[0]);
  92         case 1:
  93                 return  set1->sig[0] == set2->sig[0];
  94         }
  95         return 0;
  96 }
  97
  98 #define sigmask(sig)    (1UL << ((sig) - 1))
  99
 100 #ifndef __HAVE_ARCH_SIG_SETOPS
 101 #include <linux/string.h>
 102
 103 #define _SIG_SET_BINOP(name, op)                                        \
 104 static inline void name(sigset_t *r, const sigset_t *a, const sigset_t *b) \
 105 {                                                                       \
 106         unsigned long a0, a1, a2, a3, b0, b1, b2, b3;                   \
 107                                                                         \
 108         switch (_NSIG_WORDS) {                                          \
 109         case 4:                                                         \
 110                 a3 = a->sig[3]; a2 = a->sig[2];                         \
 111                 b3 = b->sig[3]; b2 = b->sig[2];                         \
 112                 r->sig[3] = op(a3, b3);                                 \
 113                 r->sig[2] = op(a2, b2);                                 \
 114         case 2:                                                         \
 115                 a1 = a->sig[1]; b1 = b->sig[1];                         \
 116                 r->sig[1] = op(a1, b1);                                 \
 117         case 1:                                                         \
 118                 a0 = a->sig[0]; b0 = b->sig[0];                         \
 119                 r->sig[0] = op(a0, b0);                                 \
 120                 break;                                                  \
 121         default:                                                        \
 122                 BUILD_BUG();                                            \
 123         }                                                               \
 124 }
 125
 126 #define _sig_or(x,y)    ((x) | (y))
 127 _SIG_SET_BINOP(sigorsets, _sig_or)
 128
 129 #define _sig_and(x,y)   ((x) & (y))
 130 _SIG_SET_BINOP(sigandsets, _sig_and)
 131
 132 #define _sig_andn(x,y)  ((x) & ~(y))
 133 _SIG_SET_BINOP(sigandnsets, _sig_andn)
 134
 135 #undef _SIG_SET_BINOP
 136 #undef _sig_or
 137 #undef _sig_and
 138 #undef _sig_andn
 139
 140 #define _SIG_SET_OP(name, op)                                           \
 141 static inline void name(sigset_t *set)                                  \
 142 {                                                                       \
 143         switch (_NSIG_WORDS) {                                          \
 144         case 4: set->sig[3] = op(set->sig[3]);                          \
 145                 set->sig[2] = op(set->sig[2]);                          \
 146         case 2: set->sig[1] = op(set->sig[1]);                          \
 147         case 1: set->sig[0] = op(set->sig[0]);                          \
 148                     break;                                              \
 149         default:                                                        \
 150                 BUILD_BUG();                                            \
 151         }                                                               \
 152 }
 153
 154 #define _sig_not(x)     (~(x))
 155 _SIG_SET_OP(signotset, _sig_not)
 156
 157 #undef _SIG_SET_OP
 158 #undef _sig_not
 159
 160 static inline void sigemptyset(sigset_t *set)
 161 {
 162         switch (_NSIG_WORDS) {
 163         default:
 164                 memset(set, 0, sizeof(sigset_t));
 165                 break;
 166         case 2: set->sig[1] = 0;
 167         case 1: set->sig[0] = 0;
 168                 break;
 169         }
 170 }
 171
 172 static inline void sigfillset(sigset_t *set)
 173 {
 174         switch (_NSIG_WORDS) {
 175         default:
 176                 memset(set, -1, sizeof(sigset_t));
 177                 break;
 178         case 2: set->sig[1] = -1;
 179         case 1: set->sig[0] = -1;
 180                 break;
 181         }
 182 }
 183
 184 /* Some extensions for manipulating the low 32 signals in particular.  */
 185
 186 static inline void sigaddsetmask(sigset_t *set, unsigned long mask)
 187 {
 188         set->sig[0] |= mask;
 189 }
 190
 191 static inline void sigdelsetmask(sigset_t *set, unsigned long mask)
 192 {
 193         set->sig[0] &= ~mask;
 194 }
 195
 196 static inline int sigtestsetmask(sigset_t *set, unsigned long mask)
 197 {
 198         return (set->sig[0] & mask) != 0;
 199 }
 200
 201 static inline void siginitset(sigset_t *set, unsigned long mask)
 202 {
 203         set->sig[0] = mask;
 204         switch (_NSIG_WORDS) {
 205         default:
 206                 memset(&set->sig[1], 0, sizeof(long)*(_NSIG_WORDS-1));
 207                 break;
 208         case 2: set->sig[1] = 0;
 209         case 1: ;
 210         }
 211 }
 212
 213 static inline void siginitsetinv(sigset_t *set, unsigned long mask)
 214 {
 215         set->sig[0] = ~mask;
 216         switch (_NSIG_WORDS) {
 217         default:
 218                 memset(&set->sig[1], -1, sizeof(long)*(_NSIG_WORDS-1));
 219                 break;
 220         case 2: set->sig[1] = -1;
 221         case 1: ;
 222         }
 223 }
 224
 225 #endif /* __HAVE_ARCH_SIG_SETOPS */
 226
 227 static inline void init_sigpending(struct sigpending *sig)
 228 {
 229         sigemptyset(&sig->signal);
 230         INIT_LIST_HEAD(&sig->list);
 231 }
 232
 233 extern void flush_sigqueue(struct sigpending *queue);
 234
 235 /* Test if 'sig' is valid signal. Use this instead of testing _NSIG directly */
 236 static inline int valid_signal(unsigned long sig)
 237 {
 238         return sig <= _NSIG ? 1 : 0;
 239 }
 240
 241 struct timespec;
 242 struct pt_regs;
 243
 244 extern int next_signal(struct sigpending *pending, sigset_t *mask);
 245 extern int do_send_sig_info(int sig, struct siginfo *info,
 246                                 struct task_struct *p, bool group);
 247 extern int group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p);
 248 extern int __group_send_sig_info(int, struct siginfo *, struct task_struct *);
 249 extern int do_sigtimedwait(const sigset_t *, siginfo_t *,
 250                                 const struct timespec *);
 251 extern int sigprocmask(int, sigset_t *, sigset_t *);
 252 extern void set_current_blocked(sigset_t *);
 253 extern void __set_current_blocked(const sigset_t *);
 254 extern int show_unhandled_signals;
 255
 256 extern int get_signal(struct ksignal *ksig);
 257 extern void signal_setup_done(int failed, struct ksignal *ksig, int stepping);
 258 extern void exit_signals(struct task_struct *tsk);
 259 extern void kernel_sigaction(int, __sighandler_t);
 260
 261 static inline void allow_signal(int sig)
 262 {
 263         /*
 264          * Kernel threads handle their own signals. Let the signal code
 265          * know it'll be handled, so that they don't get converted to
 266          * SIGKILL or just silently dropped.
 267          */
 268         kernel_sigaction(sig, (__force __sighandler_t)2);
 269 }
 270
 271 static inline void disallow_signal(int sig)
 272 {
 273         kernel_sigaction(sig, SIG_IGN);
 274 }
 275
 276 extern struct kmem_cache *sighand_cachep;
 277
 278 int unhandled_signal(struct task_struct *tsk, int sig);
 279
 280 /*
 281  * In POSIX a signal is sent either to a specific thread (Linux task)
 282  * or to the process as a whole (Linux thread group).  How the signal
 283  * is sent determines whether it's to one thread or the whole group,
 284  * which determines which signal mask(s) are involved in blocking it
 285  * from being delivered until later.  When the signal is delivered,
 286  * either it's caught or ignored by a user handler or it has a default
 287  * effect that applies to the whole thread group (POSIX process).
 288  *
 289  * The possible effects an unblocked signal set to SIG_DFL can have are:
 290  *   ignore     - Nothing Happens
 291  *   terminate  - kill the process, i.e. all threads in the group,
 292  *                similar to exit_group.  The group leader (only) reports
 293  *                WIFSIGNALED status to its parent.
 294  *   coredump   - write a core dump file describing all threads using
 295  *                the same mm and then kill all those threads
 296  *   stop       - stop all the threads in the group, i.e. TASK_STOPPED state
 297  *
 298  * SIGKILL and SIGSTOP cannot be caught, blocked, or ignored.
 299  * Other signals when not blocked and set to SIG_DFL behaves as follows.
 300  * The job control signals also have other special effects.
 301  *
 302  *      +--------------------+------------------+
 303  *      |  POSIX signal      |  default action  |
 304  *      +--------------------+------------------+
 305  *      |  SIGHUP            |  terminate       |
 306  *      |  SIGINT            |  terminate       |
 307  *      |  SIGQUIT           |  coredump        |
 308  *      |  SIGILL            |  coredump        |
 309  *      |  SIGTRAP           |  coredump        |
 310  *      |  SIGABRT/SIGIOT    |  coredump        |
 311  *      |  SIGBUS            |  coredump        |
 312  *      |  SIGFPE            |  coredump        |
 313  *      |  SIGKILL           |  terminate(+)    |
 314  *      |  SIGUSR1           |  terminate       |
 315  *      |  SIGSEGV           |  coredump        |
 316  *      |  SIGUSR2           |  terminate       |
 317  *      |  SIGPIPE           |  terminate       |
 318  *      |  SIGALRM           |  terminate       |
 319  *      |  SIGTERM           |  terminate       |
 320  *      |  SIGCHLD           |  ignore          |
 321  *      |  SIGCONT           |  ignore(*)       |
 322  *      |  SIGSTOP           |  stop(*)(+)      |
 323  *      |  SIGTSTP           |  stop(*)         |
 324  *      |  SIGTTIN           |  stop(*)         |
 325  *      |  SIGTTOU           |  stop(*)         |
 326  *      |  SIGURG            |  ignore          |
 327  *      |  SIGXCPU           |  coredump        |
 328  *      |  SIGXFSZ           |  coredump        |
 329  *      |  SIGVTALRM         |  terminate       |
 330  *      |  SIGPROF           |  terminate       |
 331  *      |  SIGPOLL/SIGIO     |  terminate       |
 332  *      |  SIGSYS/SIGUNUSED  |  coredump        |
 333  *      |  SIGSTKFLT         |  terminate       |
 334  *      |  SIGWINCH          |  ignore          |
 335  *      |  SIGPWR            |  terminate       |
 336  *      |  SIGRTMIN-SIGRTMAX |  terminate       |
 337  *      +--------------------+------------------+
 338  *      |  non-POSIX signal  |  default action  |
 339  *      +--------------------+------------------+
 340  *      |  SIGEMT            |  coredump        |
 341  *      +--------------------+------------------+
 342  *
 343  * (+) For SIGKILL and SIGSTOP the action is "always", not just "default".
 344  * (*) Special job control effects:
 345  * When SIGCONT is sent, it resumes the process (all threads in the group)
 346  * from TASK_STOPPED state and also clears any pending/queued stop signals
 347  * (any of those marked with "stop(*)").  This happens regardless of blocking,
 348  * catching, or ignoring SIGCONT.  When any stop signal is sent, it clears
 349  * any pending/queued SIGCONT signals; this happens regardless of blocking,
 350  * catching, or ignored the stop signal, though (except for SIGSTOP) the
 351  * default action of stopping the process may happen later or never.
 352  */
 353
 354 #ifdef SIGEMT
 355 #define SIGEMT_MASK     rt_sigmask(SIGEMT)
 356 #else
 357 #define SIGEMT_MASK     0
 358 #endif
 359
 360 #if SIGRTMIN > BITS_PER_LONG
 361 #define rt_sigmask(sig) (1ULL << ((sig)-1))
 362 #else
 363 #define rt_sigmask(sig) sigmask(sig)
 364 #endif
 365
 366 #define siginmask(sig, mask) \
 367         ((sig) < SIGRTMIN && (rt_sigmask(sig) & (mask)))
 368
 369 #define SIG_KERNEL_ONLY_MASK (\
 370         rt_sigmask(SIGKILL)   |  rt_sigmask(SIGSTOP))
 371
 372 #define SIG_KERNEL_STOP_MASK (\
 373         rt_sigmask(SIGSTOP)   |  rt_sigmask(SIGTSTP)   | \
 374         rt_sigmask(SIGTTIN)   |  rt_sigmask(SIGTTOU)   )
 375
 376 #define SIG_KERNEL_COREDUMP_MASK (\
 377         rt_sigmask(SIGQUIT)   |  rt_sigmask(SIGILL)    | \
 378         rt_sigmask(SIGTRAP)   |  rt_sigmask(SIGABRT)   | \
 379         rt_sigmask(SIGFPE)    |  rt_sigmask(SIGSEGV)   | \
 380         rt_sigmask(SIGBUS)    |  rt_sigmask(SIGSYS)    | \
 381         rt_sigmask(SIGXCPU)   |  rt_sigmask(SIGXFSZ)   | \
 382         SIGEMT_MASK                                    )
 383
 384 #define SIG_KERNEL_IGNORE_MASK (\
 385         rt_sigmask(SIGCONT)   |  rt_sigmask(SIGCHLD)   | \
 386         rt_sigmask(SIGWINCH)  |  rt_sigmask(SIGURG)    )
 387
 388 #define sig_kernel_only(sig)            siginmask(sig, SIG_KERNEL_ONLY_MASK)
 389 #define sig_kernel_coredump(sig)        siginmask(sig, SIG_KERNEL_COREDUMP_MASK)
 390 #define sig_kernel_ignore(sig)          siginmask(sig, SIG_KERNEL_IGNORE_MASK)
 391 #define sig_kernel_stop(sig)            siginmask(sig, SIG_KERNEL_STOP_MASK)
 392
 393 #define sig_user_defined(t, signr) \
 394         (((t)->sighand->action[(signr)-1].sa.sa_handler != SIG_DFL) &&  \
 395          ((t)->sighand->action[(signr)-1].sa.sa_handler != SIG_IGN))
 396
 397 #define sig_fatal(t, signr) \
 398         (!siginmask(signr, SIG_KERNEL_IGNORE_MASK|SIG_KERNEL_STOP_MASK) && \
 399          (t)->sighand->action[(signr)-1].sa.sa_handler == SIG_DFL)
 400
 401 void signals_init(void);
 402
 403 int restore_altstack(const stack_t __user *);
 404 int __save_altstack(stack_t __user *, unsigned long);
 405
 406 #define save_altstack_ex(uss, sp) do { \
 407         stack_t __user *__uss = uss; \
 408         struct task_struct *t = current; \
 409         put_user_ex((void __user *)t->sas_ss_sp, &__uss->ss_sp); \
 410         put_user_ex(t->sas_ss_flags, &__uss->ss_flags); \
 411         put_user_ex(t->sas_ss_size, &__uss->ss_size); \
 412         if (t->sas_ss_flags & SS_AUTODISARM) \
 413                 sas_ss_reset(t); \
 414 } while (0);
 415
 416 #ifdef CONFIG_PROC_FS
 417 struct seq_file;
 418 extern void render_sigset_t(struct seq_file *, const char *, sigset_t *);
 419 #endif
 420
 421 #endif /* _LINUX_SIGNAL_H */