sysdeps/unix/sysv/linux/nptl-signals.h

   1 /* Special use of signals in NPTL internals.  Linux version.
   2    Copyright (C) 2014-2018 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    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <signal.h>
  20 #include <sigsetops.h>
  21
  22 /* The signal used for asynchronous cancelation.  */
  23 #define SIGCANCEL       __SIGRTMIN
  24
  25
  26 /* Signal needed for the kernel-supported POSIX timer implementation.
  27    We can reuse the cancellation signal since we can distinguish
  28    cancellation from timer expirations.  */
  29 #define SIGTIMER        SIGCANCEL
  30
  31
  32 /* Signal used to implement the setuid et.al. functions.  */
  33 #define SIGSETXID       (__SIGRTMIN + 1)
  34
  35
  36 /* Return is sig is used internally.  */
  37 static inline int
  38 __nptl_is_internal_signal (int sig)
  39 {
  40   return (sig == SIGCANCEL) || (sig == SIGTIMER) || (sig == SIGSETXID);
  41 }
  42
  43 /* Remove internal glibc signal from the mask.  */
  44 static inline void
  45 __nptl_clear_internal_signals (sigset_t *set)
  46 {
  47   __sigdelset (set, SIGCANCEL);
  48   __sigdelset (set, SIGTIMER);
  49   __sigdelset (set, SIGSETXID);
  50 }
  51
  52 #define SIGALL_SET \
  53   ((__sigset_t) { .__val = {[0 ...  _SIGSET_NWORDS-1 ] =  -1 } })
  54
  55 /* Block all signals, including internal glibc ones.  */
  56 static inline int
  57 __libc_signal_block_all (sigset_t *set)
  58 {
  59   INTERNAL_SYSCALL_DECL (err);
  60   return INTERNAL_SYSCALL (rt_sigprocmask, err, 4, SIG_BLOCK, &SIGALL_SET,
  61                            set, _NSIG / 8);
  62 }
  63
  64 /* Block all application signals (excluding internal glibc ones).  */
  65 static inline int
  66 __libc_signal_block_app (sigset_t *set)
  67 {
  68   sigset_t allset = SIGALL_SET;
  69   __nptl_clear_internal_signals (&allset);
  70   INTERNAL_SYSCALL_DECL (err);
  71   return INTERNAL_SYSCALL (rt_sigprocmask, err, 4, SIG_BLOCK, &allset, set,
  72                            _NSIG / 8);
  73 }
  74
  75 /* Restore current process signal mask.  */
  76 static inline int
  77 __libc_signal_restore_set (const sigset_t *set)
  78 {
  79   INTERNAL_SYSCALL_DECL (err);
  80   return INTERNAL_SYSCALL (rt_sigprocmask, err, 4, SIG_SETMASK, set, NULL,
  81                            _NSIG / 8);
  82 }
  83
  84 /* Used to communicate with signal handler.  */
  85 extern struct xid_command *__xidcmd attribute_hidden;