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