sysdeps/unix/sysv/linux/sigsetops.h

   1 /* __sigset_t manipulators.  Linux version.
   2    Copyright (C) 1991-2024 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #ifndef _SIGSETOPS_H
  20 #define _SIGSETOPS_H 1
  21
  22 #include <signal.h>
  23 #include <limits.h>
  24 #include <libc-pointer-arith.h>
  25
  26 /* Return a mask that includes the bit for SIG only.  */
  27 #define __sigmask(sig) \
  28   (1UL << (((sig) - 1) % ULONG_WIDTH))
  29
  30 /* Return the word index for SIG.  */
  31 static inline unsigned long int
  32 __sigword (int sig)
  33 {
  34   return (sig - 1) / ULONG_WIDTH;
  35 }
  36
  37 /* Linux sig* functions only handle up to __NSIG_WORDS words instead of
  38    full _SIGSET_NWORDS sigset size.  The signal numbers are 1-based, and
  39    bit 0 of a signal mask is for signal 1.  */
  40 #define __NSIG_WORDS (ALIGN_UP ((_NSIG - 1), ULONG_WIDTH) / ULONG_WIDTH)
  41 _Static_assert (__NSIG_WORDS <= _SIGSET_NWORDS,
  42                 "__NSIG_WORDS > _SIGSET_WORDS");
  43
  44 /* This macro is used on syscall that takes a sigset_t to specify the expected
  45    size in bytes.  As for glibc, kernel sigset is implemented as an array of
  46    unsigned long.  */
  47 #define __NSIG_BYTES (__NSIG_WORDS * (ULONG_WIDTH / UCHAR_WIDTH))
  48
  49 static inline void
  50 __sigemptyset (sigset_t *set)
  51 {
  52   int cnt = __NSIG_WORDS;
  53   while (--cnt >= 0)
  54    set->__val[cnt] = 0;
  55 }
  56
  57 static inline void
  58 __sigfillset (sigset_t *set)
  59 {
  60   int cnt = __NSIG_WORDS;
  61   while (--cnt >= 0)
  62    set->__val[cnt] = ~0UL;
  63 }
  64
  65 static inline int
  66 __sigisemptyset (const sigset_t *set)
  67 {
  68   int cnt = __NSIG_WORDS;
  69   int ret = set->__val[--cnt];
  70   while (ret == 0 && --cnt >= 0)
  71     ret = set->__val[cnt];
  72   return ret == 0;
  73 }
  74
  75 static inline void
  76 __sigandset (sigset_t *dest, const sigset_t *left, const sigset_t *right)
  77 {
  78   int cnt = __NSIG_WORDS;
  79   while (--cnt >= 0)
  80     dest->__val[cnt] = left->__val[cnt] & right->__val[cnt];
  81 }
  82
  83 static inline void
  84 __sigorset (sigset_t *dest, const sigset_t *left, const sigset_t *right)
  85 {
  86   int cnt = __NSIG_WORDS;
  87   while (--cnt >= 0)
  88     dest->__val[cnt] = left->__val[cnt] | right->__val[cnt];
  89 }
  90
  91 static inline int
  92 __sigismember (const sigset_t *set, int sig)
  93 {
  94   unsigned long int mask = __sigmask (sig);
  95   unsigned long int word = __sigword (sig);
  96   return set->__val[word] & mask ? 1 : 0;
  97 }
  98
  99 static inline void
 100 __sigaddset (sigset_t *set, int sig)
 101 {
 102   unsigned long int mask = __sigmask (sig);
 103   unsigned long int word = __sigword (sig);
 104   set->__val[word] |= mask;
 105 }
 106
 107 static inline void
 108 __sigdelset (sigset_t *set, int sig)
 109 {
 110   unsigned long int mask = __sigmask (sig);
 111   unsigned long int word = __sigword (sig);
 112   set->__val[word] &= ~mask;
 113 }
 114
 115 #endif /* bits/sigsetops.h */