sysdeps/unix/sysv/linux/arm/sigaction.c

   1 /* Copyright (C) 1997-2018 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    <http://www.gnu.org/licenses/>.  */
  17
  18 #include <errno.h>
  19 #include <signal.h>
  20 #include <string.h>
  21
  22 #include <sysdep.h>
  23 #include <sys/syscall.h>
  24
  25 /* The difference here is that the sigaction structure used in the
  26    kernel is not the same as we use in the libc.  Therefore we must
  27    translate it here.  */
  28 #include <kernel_sigaction.h>
  29
  30 #define SA_RESTORER     0x04000000
  31
  32 extern void __default_sa_restorer (void);
  33 extern void __default_rt_sa_restorer (void);
  34
  35 /* When RT signals are in use we need to use a different return stub.  */
  36 #define choose_restorer(flags)                                  \
  37   (flags & SA_SIGINFO) ? __default_rt_sa_restorer               \
  38   : __default_sa_restorer
  39
  40 /* If ACT is not NULL, change the action for SIG to *ACT.
  41    If OACT is not NULL, put the old action for SIG in *OACT.  */
  42 int
  43 __libc_sigaction (int sig, const struct sigaction *act, struct sigaction *oact)
  44 {
  45   int result;
  46
  47   struct kernel_sigaction kact, koact;
  48
  49   if (act)
  50     {
  51       kact.k_sa_handler = act->sa_handler;
  52       memcpy (&kact.sa_mask, &act->sa_mask, sizeof (sigset_t));
  53       kact.sa_flags = act->sa_flags;
  54 #ifdef HAVE_SA_RESTORER
  55       if (kact.sa_flags & SA_RESTORER)
  56         kact.sa_restorer = act->sa_restorer;
  57       else
  58         {
  59           kact.sa_restorer = choose_restorer (kact.sa_flags);
  60           kact.sa_flags |= SA_RESTORER;
  61         }
  62 #endif
  63     }
  64
  65   /* XXX The size argument hopefully will have to be changed to the
  66      real size of the user-level sigset_t.  */
  67   result = INLINE_SYSCALL (rt_sigaction, 4, sig,
  68                            act ? &kact : NULL,
  69                            oact ? &koact : NULL, _NSIG / 8);
  70
  71   if (oact && result >= 0)
  72     {
  73       oact->sa_handler = koact.k_sa_handler;
  74       memcpy (&oact->sa_mask, &koact.sa_mask, sizeof (sigset_t));
  75       oact->sa_flags = koact.sa_flags;
  76 #ifdef HAVE_SA_RESTORER
  77       oact->sa_restorer = koact.sa_restorer;
  78 #endif
  79     }
  80   return result;
  81 }
  82 libc_hidden_def (__libc_sigaction)
  83
  84 #include <nptl/sigaction.c>