signal/signal.h

   1 /* Copyright (C) 1991-2023 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-generic.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   __attribute_deprecated_msg__ ("Use the sigsuspend function instead");
 153 # else
 154 extern int __sigpause (int __sig_or_mask, int __is_sig);
 155 /* Remove a signal from the signal mask and suspend the process.  */
 156 #  define sigpause(sig) __sigpause ((sig), 1)
 157 # endif
 158 #endif
 159
 160
 161 #ifdef __USE_MISC
 162 /* None of the following functions should be used anymore.  They are here
 163    only for compatibility.  A single word (`int') is not guaranteed to be
 164    enough to hold a complete signal mask and therefore these functions
 165    simply do not work in many situations.  Use `sigprocmask' instead.  */
 166
 167 /* Compute mask for signal SIG.  */
 168 # define sigmask(sig) \
 169   __glibc_macro_warning ("sigmask is deprecated") \
 170   ((int)(1u << ((sig) - 1)))
 171
 172 /* Block signals in MASK, returning the old mask.  */
 173 extern int sigblock (int __mask) __THROW __attribute_deprecated__;
 174
 175 /* Set the mask of blocked signals to MASK, returning the old mask.  */
 176 extern int sigsetmask (int __mask) __THROW __attribute_deprecated__;
 177
 178 /* Return currently selected signal mask.  */
 179 extern int siggetmask (void) __THROW __attribute_deprecated__;
 180 #endif /* Use misc.  */
 181
 182
 183 #ifdef __USE_MISC
 184 # define NSIG   _NSIG
 185 #endif
 186
 187 #ifdef __USE_GNU
 188 typedef __sighandler_t sighandler_t;
 189 #endif
 190
 191 /* 4.4 BSD uses the name `sig_t' for this.  */
 192 #ifdef __USE_MISC
 193 typedef __sighandler_t sig_t;
 194 #endif
 195
 196 #ifdef __USE_POSIX
 197
 198 /* Clear all signals from SET.  */
 199 extern int sigemptyset (sigset_t *__set) __THROW __nonnull ((1));
 200
 201 /* Set all signals in SET.  */
 202 extern int sigfillset (sigset_t *__set) __THROW __nonnull ((1));
 203
 204 /* Add SIGNO to SET.  */
 205 extern int sigaddset (sigset_t *__set, int __signo) __THROW __nonnull ((1));
 206
 207 /* Remove SIGNO from SET.  */
 208 extern int sigdelset (sigset_t *__set, int __signo) __THROW __nonnull ((1));
 209
 210 /* Return 1 if SIGNO is in SET, 0 if not.  */
 211 extern int sigismember (const sigset_t *__set, int __signo)
 212      __THROW __nonnull ((1));
 213
 214 # ifdef __USE_GNU
 215 /* Return non-empty value is SET is not empty.  */
 216 extern int sigisemptyset (const sigset_t *__set) __THROW __nonnull ((1));
 217
 218 /* Build new signal set by combining the two inputs set using logical AND.  */
 219 extern int sigandset (sigset_t *__set, const sigset_t *__left,
 220                       const sigset_t *__right) __THROW __nonnull ((1, 2, 3));
 221
 222 /* Build new signal set by combining the two inputs set using logical OR.  */
 223 extern int sigorset (sigset_t *__set, const sigset_t *__left,
 224                      const sigset_t *__right) __THROW __nonnull ((1, 2, 3));
 225 # endif /* GNU */
 226
 227 /* Get the system-specific definitions of `struct sigaction'
 228    and the `SA_*' and `SIG_*'. constants.  */
 229 # include <bits/sigaction.h>
 230
 231 /* Get and/or change the set of blocked signals.  */
 232 extern int sigprocmask (int __how, const sigset_t *__restrict __set,
 233                         sigset_t *__restrict __oset) __THROW;
 234
 235 /* Change the set of blocked signals to SET,
 236    wait until a signal arrives, and restore the set of blocked signals.
 237
 238    This function is a cancellation point and therefore not marked with
 239    __THROW.  */
 240 extern int sigsuspend (const sigset_t *__set) __nonnull ((1));
 241
 242 /* Get and/or set the action for signal SIG.  */
 243 extern int sigaction (int __sig, const struct sigaction *__restrict __act,
 244                       struct sigaction *__restrict __oact) __THROW;
 245
 246 /* Put in SET all signals that are blocked and waiting to be delivered.  */
 247 extern int sigpending (sigset_t *__set) __THROW __nonnull ((1));
 248
 249
 250 # ifdef __USE_POSIX199506
 251 /* Select any of pending signals from SET or wait for any to arrive.
 252
 253    This function is a cancellation point and therefore not marked with
 254    __THROW.  */
 255 extern int sigwait (const sigset_t *__restrict __set, int *__restrict __sig)
 256      __nonnull ((1, 2));
 257 # endif /* Use POSIX 1995.  */
 258
 259 # ifdef __USE_POSIX199309
 260 /* Select any of pending signals from SET and place information in INFO.
 261
 262    This function is a cancellation point and therefore not marked with
 263    __THROW.  */
 264 extern int sigwaitinfo (const sigset_t *__restrict __set,
 265                         siginfo_t *__restrict __info) __nonnull ((1));
 266
 267 /* Select any of pending signals from SET and place information in INFO.
 268    Wait the time specified by TIMEOUT if no signal is pending.
 269
 270    This function is a cancellation point and therefore not marked with
 271    __THROW.  */
 272 #  ifndef __USE_TIME_BITS64
 273 extern int sigtimedwait (const sigset_t *__restrict __set,
 274                          siginfo_t *__restrict __info,
 275                          const struct timespec *__restrict __timeout)
 276      __nonnull ((1));
 277 #  else
 278 #   ifdef __REDIRECT
 279 extern int __REDIRECT (sigtimedwait,
 280                        (const sigset_t *__restrict __set,
 281                         siginfo_t *__restrict __info,
 282                         const struct timespec *__restrict __timeout),
 283                        __sigtimedwait64)
 284      __nonnull ((1));
 285 #   else
 286 #    define sigtimedwait __sigtimedwait64
 287 #   endif
 288 #  endif
 289
 290 /* Send signal SIG to the process PID.  Associate data in VAL with the
 291    signal.  */
 292 extern int sigqueue (__pid_t __pid, int __sig, const union sigval __val)
 293      __THROW;
 294 # endif /* Use POSIX 199306.  */
 295
 296 #endif /* Use POSIX.  */
 297
 298 #ifdef __USE_MISC
 299
 300 /* Get machine-dependent `struct sigcontext' and signal subcodes.  */
 301 # include <bits/sigcontext.h>
 302
 303 /* Restore the state saved in SCP.  */
 304 extern int sigreturn (struct sigcontext *__scp) __THROW;
 305
 306 #endif /* Use misc.  */
 307
 308
 309 #if defined __USE_XOPEN_EXTENDED || defined __USE_XOPEN2K8
 310 # define __need_size_t
 311 # include <stddef.h>
 312
 313 # include <bits/types/stack_t.h>
 314 # if defined __USE_XOPEN || defined __USE_XOPEN2K8
 315 /* This will define `ucontext_t' and `mcontext_t'.  */
 316 #  include <sys/ucontext.h>
 317 # endif
 318 #endif /* Use POSIX.1-2008 or X/Open Unix.  */
 319
 320 #if defined __USE_XOPEN_EXTENDED || defined __USE_MISC
 321 /* If INTERRUPT is nonzero, make signal SIG interrupt system calls
 322    (causing them to fail with EINTR); if INTERRUPT is zero, make system
 323    calls be restarted after signal SIG.  */
 324 extern int siginterrupt (int __sig, int __interrupt) __THROW
 325   __attribute_deprecated_msg__ ("Use sigaction with SA_RESTART instead");
 326
 327 # include <bits/sigstack.h>
 328 # include <bits/sigstksz.h>
 329 # include <bits/ss_flags.h>
 330
 331 /* Alternate signal handler stack interface.
 332    This interface should always be preferred over `sigstack'.  */
 333 extern int sigaltstack (const stack_t *__restrict __ss,
 334                         stack_t *__restrict __oss) __THROW;
 335 #endif /* __USE_XOPEN_EXTENDED || __USE_MISC */
 336
 337 #if ((defined __USE_XOPEN_EXTENDED && !defined __USE_XOPEN2K8)  \
 338      || defined __USE_MISC)
 339 # include <bits/types/struct_sigstack.h>
 340 #endif
 341
 342 #if ((defined __USE_XOPEN_EXTENDED && !defined __USE_XOPEN2K)   \
 343      || defined __USE_MISC)
 344 /* Run signals handlers on the stack specified by SS (if not NULL).
 345    If OSS is not NULL, it is filled in with the old signal stack status.
 346    This interface is obsolete and on many platform not implemented.  */
 347 extern int sigstack (struct sigstack *__ss, struct sigstack *__oss)
 348      __THROW __attribute_deprecated__;
 349 #endif
 350
 351 #ifdef __USE_XOPEN_EXTENDED
 352 /* Simplified interface for signal management.  */
 353
 354 /* Add SIG to the calling process' signal mask.  */
 355 extern int sighold (int __sig) __THROW
 356   __attribute_deprecated_msg__ ("Use the sigprocmask function instead");
 357
 358 /* Remove SIG from the calling process' signal mask.  */
 359 extern int sigrelse (int __sig) __THROW
 360   __attribute_deprecated_msg__ ("Use the sigprocmask function instead");
 361
 362 /* Set the disposition of SIG to SIG_IGN.  */
 363 extern int sigignore (int __sig) __THROW
 364   __attribute_deprecated_msg__ ("Use the signal function instead");
 365
 366 /* Set the disposition of SIG.  */
 367 extern __sighandler_t sigset (int __sig, __sighandler_t __disp) __THROW
 368   __attribute_deprecated_msg__
 369     ("Use the signal and sigprocmask functions instead");
 370 #endif
 371
 372 #if defined __USE_POSIX199506 || defined __USE_UNIX98
 373 /* Some of the functions for handling signals in threaded programs must
 374    be defined here.  */
 375 # include <bits/pthreadtypes.h>
 376 # include <bits/sigthread.h>
 377 #endif /* use Unix98 */
 378
 379 /* The following functions are used internally in the C library and in
 380    other code which need deep insights.  */
 381
 382 /* Return number of available real-time signal with highest priority.  */
 383 extern int __libc_current_sigrtmin (void) __THROW;
 384 /* Return number of available real-time signal with lowest priority.  */
 385 extern int __libc_current_sigrtmax (void) __THROW;
 386
 387 #define SIGRTMIN        (__libc_current_sigrtmin ())
 388 #define SIGRTMAX        (__libc_current_sigrtmax ())
 389
 390 /* System-specific extensions.  */
 391 #include <bits/signal_ext.h>
 392
 393 __END_DECLS
 394
 395 #endif /* not signal.h */