signal/signal.h

   1 /* Copyright (C) 1991-2020 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <https://www.gnu.org/licenses/>.  */
  17
  18 /*
  19  *      ISO C99 Standard: 7.14 Signal handling <signal.h>
  20  */
  21
  22 #ifndef _SIGNAL_H
  23 #define _SIGNAL_H
  24
  25 #include <features.h>
  26
  27 __BEGIN_DECLS
  28
  29 #include <bits/types.h>
  30 #include <bits/signum.h>
  31
  32 #include <bits/types/sig_atomic_t.h>
  33
  34 #if defined __USE_POSIX
  35 #include <bits/types/sigset_t.h>
  36 #endif
  37
  38 #if defined __USE_XOPEN || defined __USE_XOPEN2K
  39 # ifndef __pid_t_defined
  40 typedef __pid_t pid_t;
  41 #  define __pid_t_defined
  42 #endif
  43 #ifdef __USE_XOPEN
  44 # endif
  45 # ifndef __uid_t_defined
  46 typedef __uid_t uid_t;
  47 #  define __uid_t_defined
  48 # endif
  49 #endif  /* Unix98 */
  50
  51 #ifdef __USE_POSIX199309
  52 /* We need `struct timespec' later on.  */
  53 # include <bits/types/struct_timespec.h>
  54 #endif
  55
  56 #if defined __USE_POSIX199309 || defined __USE_XOPEN_EXTENDED
  57 # include <bits/types/siginfo_t.h>
  58 # include <bits/siginfo-consts.h>
  59 #endif
  60
  61 #ifdef __USE_MISC
  62 # include <bits/types/sigval_t.h>
  63 #endif
  64
  65 #ifdef __USE_POSIX199309
  66 # include <bits/types/sigevent_t.h>
  67 # include <bits/sigevent-consts.h>
  68 #endif
  69
  70
  71 /* Type of a signal handler.  */
  72 typedef void (*__sighandler_t) (int);
  73
  74 /* The X/Open definition of `signal' specifies the SVID semantic.  Use
  75    the additional function `sysv_signal' when X/Open compatibility is
  76    requested.  */
  77 extern __sighandler_t __sysv_signal (int __sig, __sighandler_t __handler)
  78      __THROW;
  79 #ifdef __USE_GNU
  80 extern __sighandler_t sysv_signal (int __sig, __sighandler_t __handler)
  81      __THROW;
  82 #endif
  83
  84 /* Set the handler for the signal SIG to HANDLER, returning the old
  85    handler, or SIG_ERR on error.
  86    By default `signal' has the BSD semantic.  */
  87 #ifdef __USE_MISC
  88 extern __sighandler_t signal (int __sig, __sighandler_t __handler)
  89      __THROW;
  90 #else
  91 /* Make sure the used `signal' implementation is the SVID version. */
  92 # ifdef __REDIRECT_NTH
  93 extern __sighandler_t __REDIRECT_NTH (signal,
  94                                       (int __sig, __sighandler_t __handler),
  95                                       __sysv_signal);
  96 # else
  97 #  define signal __sysv_signal
  98 # endif
  99 #endif
 100
 101 #if defined __USE_XOPEN_EXTENDED && !defined __USE_XOPEN2K8
 102 /* The X/Open definition of `signal' conflicts with the BSD version.
 103    So they defined another function `bsd_signal'.  */
 104 extern __sighandler_t bsd_signal (int __sig, __sighandler_t __handler)
 105      __THROW;
 106 #endif
 107
 108 /* Send signal SIG to process number PID.  If PID is zero,
 109    send SIG to all processes in the current process's process group.
 110    If PID is < -1, send SIG to all processes in process group - PID.  */
 111 #ifdef __USE_POSIX
 112 extern int kill (__pid_t __pid, int __sig) __THROW;
 113 #endif /* Use POSIX.  */
 114
 115 #if defined __USE_MISC || defined __USE_XOPEN_EXTENDED
 116 /* Send SIG to all processes in process group PGRP.
 117    If PGRP is zero, send SIG to all processes in
 118    the current process's process group.  */
 119 extern int killpg (__pid_t __pgrp, int __sig) __THROW;
 120 #endif /* Use misc || X/Open Unix.  */
 121
 122 /* Raise signal SIG, i.e., send SIG to yourself.  */
 123 extern int raise (int __sig) __THROW;
 124
 125 #ifdef __USE_MISC
 126 /* SVID names for the same things.  */
 127 extern __sighandler_t ssignal (int __sig, __sighandler_t __handler)
 128      __THROW;
 129 extern int gsignal (int __sig) __THROW;
 130 #endif /* Use misc.  */
 131
 132 #ifdef __USE_XOPEN2K8
 133 /* Print a message describing the meaning of the given signal number.  */
 134 extern void psignal (int __sig, const char *__s);
 135
 136 /* Print a message describing the meaning of the given signal information.  */
 137 extern void psiginfo (const siginfo_t *__pinfo, const char *__s);
 138 #endif /* POSIX 2008.  */
 139
 140
 141
 142 /* The `sigpause' function in X/Open defines the argument as the
 143    signal number.  This requires redirecting to another function
 144    because the default version in glibc uses an old BSD interface.
 145
 146    This function is a cancellation point and therefore not marked with
 147    __THROW.  */
 148
 149 #ifdef __USE_XOPEN_EXTENDED
 150 # ifdef __GNUC__
 151 extern int sigpause (int __sig) __asm__ ("__xpg_sigpause");
 152 # else
 153 extern int __sigpause (int __sig_or_mask, int __is_sig);
 154 /* Remove a signal from the signal mask and suspend the process.  */
 155 #  define sigpause(sig) __sigpause ((sig), 1)
 156 # endif
 157 #endif
 158
 159
 160 #ifdef __USE_MISC
 161 /* None of the following functions should be used anymore.  They are here
 162    only for compatibility.  A single word (`int') is not guaranteed to be
 163    enough to hold a complete signal mask and therefore these functions
 164    simply do not work in many situations.  Use `sigprocmask' instead.  */
 165
 166 /* Compute mask for signal SIG.  */
 167 # define sigmask(sig) ((int)(1u << ((sig) - 1)))
 168
 169 /* Block signals in MASK, returning the old mask.  */
 170 extern int sigblock (int __mask) __THROW __attribute_deprecated__;
 171
 172 /* Set the mask of blocked signals to MASK, returning the old mask.  */
 173 extern int sigsetmask (int __mask) __THROW __attribute_deprecated__;
 174
 175 /* Return currently selected signal mask.  */
 176 extern int siggetmask (void) __THROW __attribute_deprecated__;
 177 #endif /* Use misc.  */
 178
 179
 180 #ifdef __USE_MISC
 181 # define NSIG   _NSIG
 182 #endif
 183
 184 #ifdef __USE_GNU
 185 typedef __sighandler_t sighandler_t;
 186 #endif
 187
 188 /* 4.4 BSD uses the name `sig_t' for this.  */
 189 #ifdef __USE_MISC
 190 typedef __sighandler_t sig_t;
 191 #endif
 192
 193 #ifdef __USE_POSIX
 194
 195 /* Clear all signals from SET.  */
 196 extern int sigemptyset (sigset_t *__set) __THROW __nonnull ((1));
 197
 198 /* Set all signals in SET.  */
 199 extern int sigfillset (sigset_t *__set) __THROW __nonnull ((1));
 200
 201 /* Add SIGNO to SET.  */
 202 extern int sigaddset (sigset_t *__set, int __signo) __THROW __nonnull ((1));
 203
 204 /* Remove SIGNO from SET.  */
 205 extern int sigdelset (sigset_t *__set, int __signo) __THROW __nonnull ((1));
 206
 207 /* Return 1 if SIGNO is in SET, 0 if not.  */
 208 extern int sigismember (const sigset_t *__set, int __signo)
 209      __THROW __nonnull ((1));
 210
 211 # ifdef __USE_GNU
 212 /* Return non-empty value is SET is not empty.  */
 213 extern int sigisemptyset (const sigset_t *__set) __THROW __nonnull ((1));
 214
 215 /* Build new signal set by combining the two inputs set using logical AND.  */
 216 extern int sigandset (sigset_t *__set, const sigset_t *__left,
 217                       const sigset_t *__right) __THROW __nonnull ((1, 2, 3));
 218
 219 /* Build new signal set by combining the two inputs set using logical OR.  */
 220 extern int sigorset (sigset_t *__set, const sigset_t *__left,
 221                      const sigset_t *__right) __THROW __nonnull ((1, 2, 3));
 222 # endif /* GNU */
 223
 224 /* Get the system-specific definitions of `struct sigaction'
 225    and the `SA_*' and `SIG_*'. constants.  */
 226 # include <bits/sigaction.h>
 227
 228 /* Get and/or change the set of blocked signals.  */
 229 extern int sigprocmask (int __how, const sigset_t *__restrict __set,
 230                         sigset_t *__restrict __oset) __THROW;
 231
 232 /* Change the set of blocked signals to SET,
 233    wait until a signal arrives, and restore the set of blocked signals.
 234
 235    This function is a cancellation point and therefore not marked with
 236    __THROW.  */
 237 extern int sigsuspend (const sigset_t *__set) __nonnull ((1));
 238
 239 /* Get and/or set the action for signal SIG.  */
 240 extern int sigaction (int __sig, const struct sigaction *__restrict __act,
 241                       struct sigaction *__restrict __oact) __THROW;
 242
 243 /* Put in SET all signals that are blocked and waiting to be delivered.  */
 244 extern int sigpending (sigset_t *__set) __THROW __nonnull ((1));
 245
 246
 247 # ifdef __USE_POSIX199506
 248 /* Select any of pending signals from SET or wait for any to arrive.
 249
 250    This function is a cancellation point and therefore not marked with
 251    __THROW.  */
 252 extern int sigwait (const sigset_t *__restrict __set, int *__restrict __sig)
 253      __nonnull ((1, 2));
 254 # endif /* Use POSIX 1995.  */
 255
 256 # ifdef __USE_POSIX199309
 257 /* Select any of pending signals from SET and place information in INFO.
 258
 259    This function is a cancellation point and therefore not marked with
 260    __THROW.  */
 261 extern int sigwaitinfo (const sigset_t *__restrict __set,
 262                         siginfo_t *__restrict __info) __nonnull ((1));
 263
 264 /* Select any of pending signals from SET and place information in INFO.
 265    Wait the time specified by TIMEOUT if no signal is pending.
 266
 267    This function is a cancellation point and therefore not marked with
 268    __THROW.  */
 269 extern int sigtimedwait (const sigset_t *__restrict __set,
 270                          siginfo_t *__restrict __info,
 271                          const struct timespec *__restrict __timeout)
 272      __nonnull ((1));
 273
 274 /* Send signal SIG to the process PID.  Associate data in VAL with the
 275    signal.  */
 276 extern int sigqueue (__pid_t __pid, int __sig, const union sigval __val)
 277      __THROW;
 278 # endif /* Use POSIX 199306.  */
 279
 280 #endif /* Use POSIX.  */
 281
 282 #ifdef __USE_MISC
 283
 284 /* Names of the signals.  This variable exists only for compatibility.
 285    Use `strsignal' instead (see <string.h>).  */
 286 extern const char *const _sys_siglist[_NSIG];
 287 extern const char *const sys_siglist[_NSIG];
 288
 289
 290 /* Get machine-dependent `struct sigcontext' and signal subcodes.  */
 291 # include <bits/sigcontext.h>
 292
 293 /* Restore the state saved in SCP.  */
 294 extern int sigreturn (struct sigcontext *__scp) __THROW;
 295
 296 #endif /* Use misc.  */
 297
 298
 299 #if defined __USE_XOPEN_EXTENDED || defined __USE_XOPEN2K8
 300 # define __need_size_t
 301 # include <stddef.h>
 302
 303 # include <bits/types/stack_t.h>
 304 # if defined __USE_XOPEN || defined __USE_XOPEN2K8
 305 /* This will define `ucontext_t' and `mcontext_t'.  */
 306 #  include <sys/ucontext.h>
 307 # endif
 308 #endif /* Use POSIX.1-2008 or X/Open Unix.  */
 309
 310 #if defined __USE_XOPEN_EXTENDED || defined __USE_MISC
 311 /* If INTERRUPT is nonzero, make signal SIG interrupt system calls
 312    (causing them to fail with EINTR); if INTERRUPT is zero, make system
 313    calls be restarted after signal SIG.  */
 314 extern int siginterrupt (int __sig, int __interrupt) __THROW;
 315
 316 # include <bits/sigstack.h>
 317 # include <bits/ss_flags.h>
 318
 319 /* Alternate signal handler stack interface.
 320    This interface should always be preferred over `sigstack'.  */
 321 extern int sigaltstack (const stack_t *__restrict __ss,
 322                         stack_t *__restrict __oss) __THROW;
 323 #endif /* __USE_XOPEN_EXTENDED || __USE_MISC */
 324
 325 #if ((defined __USE_XOPEN_EXTENDED && !defined __USE_XOPEN2K8)  \
 326      || defined __USE_MISC)
 327 # include <bits/types/struct_sigstack.h>
 328 #endif
 329
 330 #if ((defined __USE_XOPEN_EXTENDED && !defined __USE_XOPEN2K)   \
 331      || defined __USE_MISC)
 332 /* Run signals handlers on the stack specified by SS (if not NULL).
 333    If OSS is not NULL, it is filled in with the old signal stack status.
 334    This interface is obsolete and on many platform not implemented.  */
 335 extern int sigstack (struct sigstack *__ss, struct sigstack *__oss)
 336      __THROW __attribute_deprecated__;
 337 #endif
 338
 339 #ifdef __USE_XOPEN_EXTENDED
 340 /* Simplified interface for signal management.  */
 341
 342 /* Add SIG to the calling process' signal mask.  */
 343 extern int sighold (int __sig) __THROW;
 344
 345 /* Remove SIG from the calling process' signal mask.  */
 346 extern int sigrelse (int __sig) __THROW;
 347
 348 /* Set the disposition of SIG to SIG_IGN.  */
 349 extern int sigignore (int __sig) __THROW;
 350
 351 /* Set the disposition of SIG.  */
 352 extern __sighandler_t sigset (int __sig, __sighandler_t __disp) __THROW;
 353 #endif
 354
 355 #if defined __USE_POSIX199506 || defined __USE_UNIX98
 356 /* Some of the functions for handling signals in threaded programs must
 357    be defined here.  */
 358 # include <bits/pthreadtypes.h>
 359 # include <bits/sigthread.h>
 360 #endif /* use Unix98 */
 361
 362 /* The following functions are used internally in the C library and in
 363    other code which need deep insights.  */
 364
 365 /* Return number of available real-time signal with highest priority.  */
 366 extern int __libc_current_sigrtmin (void) __THROW;
 367 /* Return number of available real-time signal with lowest priority.  */
 368 extern int __libc_current_sigrtmax (void) __THROW;
 369
 370 #define SIGRTMIN        (__libc_current_sigrtmin ())
 371 #define SIGRTMAX        (__libc_current_sigrtmax ())
 372
 373 /* System-specific extensions.  */
 374 #include <bits/signal_ext.h>
 375
 376 __END_DECLS
 377
 378 #endif /* not signal.h */