libc/sysdeps/linux/common/internal-signals.h

   1 /* Copyright (C) 2014-2017 Free Software Foundation, Inc.
   2
   3    The GNU C Library is free software; you can redistribute it and/or
   4    modify it under the terms of the GNU Lesser General Public
   5    License as published by the Free Software Foundation; either
   6    version 2.1 of the License, or (at your option) any later version.
   7
   8    The GNU C Library is distributed in the hope that it will be useful,
   9    but WITHOUT ANY WARRANTY; without even the implied warranty of
  10    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11    Lesser General Public License for more details.
  12
  13    You should have received a copy of the GNU Lesser General Public
  14    License along with the GNU C Library; if not, see
  15    <http://www.gnu.org/licenses/>.  */
  16
  17 #include <signal.h>
  18
  19 /* The signal used for asynchronous cancelation.  */
  20 #define SIGCANCEL       __SIGRTMIN
  21
  22 /* Signal needed for the kernel-supported POSIX timer implementation.
  23    We can reuse the cancellation signal since we can distinguish
  24    cancellation from timer expirations.  */
  25 #define SIGTIMER        SIGCANCEL
  26
  27 /* Signal used to implement the setuid et.al. functions.  */
  28 #define SIGSETXID       (__SIGRTMIN + 1)
  29
  30 /* Return if sig is used internally.  */
  31 static inline int
  32 __is_internal_signal (int sig)
  33 {
  34   return (sig == SIGCANCEL) || (sig == SIGTIMER) || (sig == SIGSETXID);
  35 }
  36
  37 /* Remove internal signal from the mask.  */
  38 static inline void
  39 __clear_internal_signals (sigset_t *set)
  40 {
  41   __sigdelset (set, SIGCANCEL);
  42   __sigdelset (set, SIGTIMER);
  43   __sigdelset (set, SIGSETXID);
  44 }
  45
  46 #define SIGALL_SET \
  47   ((__sigset_t) { .__val = {[0 ...  _SIGSET_NWORDS-1 ] =  -1 } })
  48
  49 /* Block all signals, including internal ones.  */
  50 static inline int
  51 __libc_signal_block_all (sigset_t *set)
  52 {
  53   INTERNAL_SYSCALL_DECL (err);
  54   return INTERNAL_SYSCALL (rt_sigprocmask, err, 4, SIG_BLOCK, &SIGALL_SET,
  55                            set, _NSIG / 8);
  56 }
  57
  58 /* Block all application signals (excluding internal ones).  */
  59 static inline int
  60 __libc_signal_block_app (sigset_t *set)
  61 {
  62   sigset_t allset = SIGALL_SET;
  63   __clear_internal_signals (&allset);
  64   INTERNAL_SYSCALL_DECL (err);
  65   return INTERNAL_SYSCALL (rt_sigprocmask, err, 4, SIG_BLOCK, &allset, set,
  66                            _NSIG / 8);
  67 }
  68
  69 /* Restore current process signal mask.  */
  70 static inline int
  71 __libc_signal_restore_set (const sigset_t *set)
  72 {
  73   INTERNAL_SYSCALL_DECL (err);
  74   return INTERNAL_SYSCALL (rt_sigprocmask, err, 4, SIG_SETMASK, set, NULL,
  75                            _NSIG / 8);
  76 }
  77
  78 /* Used to communicate with signal handler.  */
  79 extern struct xid_command *__xidcmd attribute_hidden;