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

   1 /* Copyright (C) 1997, 1998, 1999, 2000, 2002, 2003, 2005, 2006
   2    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 <errno.h>
  20 #include <signal.h>
  21 #include <string.h>
  22
  23 #include <sysdep.h>
  24 #include <sys/syscall.h>
  25 #include <kernel-features.h>
  26
  27 /* The difference here is that the sigaction structure used in the
  28    kernel is not the same as we use in the libc.  Therefore we must
  29    translate it here.  */
  30 #include <kernel_sigaction.h>
  31
  32 /* The variable is shared between all wrappers around signal handling
  33    functions which have RT equivalents.  */
  34 int __libc_missing_rt_sigs;
  35
  36 #define SA_RESTORER     0x04000000
  37
  38 #ifdef __ARM_EABI__
  39 extern void __default_sa_restorer_v1(void);
  40 extern void __default_sa_restorer_v2(void);
  41 extern void __default_rt_sa_restorer_v1(void);
  42 extern void __default_rt_sa_restorer_v2(void);
  43 # ifdef __ASSUME_SIGFRAME_V2
  44 #  define __default_sa_restorer __default_sa_restorer_v2
  45 #  define __default_rt_sa_restorer __default_rt_sa_restorer_v2
  46 # else
  47 #  include <ldsodefs.h>
  48 #  define __default_sa_restorer (GLRO(dl_osversion) >= 0x020612 \
  49                                  ? __default_sa_restorer_v2     \
  50                                  : __default_sa_restorer_v1)
  51 #  define __default_rt_sa_restorer (GLRO(dl_osversion) >= 0x020612      \
  52                                     ? __default_rt_sa_restorer_v2       \
  53                                     : __default_rt_sa_restorer_v1)
  54 # endif
  55 #else
  56 extern void __default_sa_restorer(void);
  57 extern void __default_rt_sa_restorer(void);
  58 #endif
  59
  60 /* When RT signals are in use we need to use a different return stub.  */
  61 #ifdef __NR_rt_sigreturn
  62 #define choose_restorer(flags)                                  \
  63   (flags & SA_SIGINFO) ? __default_rt_sa_restorer               \
  64   : __default_sa_restorer
  65 #else
  66 #define choose_restorer(flags)                                  \
  67   __default_sa_restorer
  68 #endif
  69
  70 /* If ACT is not NULL, change the action for SIG to *ACT.
  71    If OACT is not NULL, put the old action for SIG in *OACT.  */
  72 int
  73 __libc_sigaction (sig, act, oact)
  74      int sig;
  75      const struct sigaction *act;
  76      struct sigaction *oact;
  77 {
  78 #ifndef __ASSUME_REALTIME_SIGNALS
  79   struct old_kernel_sigaction k_sigact, k_osigact;
  80 #endif
  81   int result;
  82
  83 #ifdef __NR_rt_sigaction
  84   /* First try the RT signals.  */
  85 # ifndef __ASSUME_REALTIME_SIGNALS
  86   if (!__libc_missing_rt_sigs)
  87 # endif
  88     {
  89       struct kernel_sigaction kact, koact;
  90 # ifndef __ASSUME_REALTIME_SIGNALS
  91       int saved_errno = errno;
  92 # endif
  93
  94       if (act)
  95         {
  96           kact.k_sa_handler = act->sa_handler;
  97           memcpy (&kact.sa_mask, &act->sa_mask, sizeof (sigset_t));
  98           kact.sa_flags = act->sa_flags;
  99 # ifdef HAVE_SA_RESTORER
 100           if (kact.sa_flags & SA_RESTORER)
 101             kact.sa_restorer = act->sa_restorer;
 102           else
 103             {
 104               kact.sa_restorer = choose_restorer (kact.sa_flags);
 105               kact.sa_flags |= SA_RESTORER;
 106             }
 107 # endif
 108         }
 109
 110       /* XXX The size argument hopefully will have to be changed to the
 111          real size of the user-level sigset_t.  */
 112       result = INLINE_SYSCALL (rt_sigaction, 4, sig,
 113                                act ? __ptrvalue (&kact) : NULL,
 114                                oact ? __ptrvalue (&koact) : NULL, _NSIG / 8);
 115
 116 # ifndef __ASSUME_REALTIME_SIGNALS
 117       if (result >= 0 || errno != ENOSYS)
 118 # endif
 119         {
 120           if (oact && result >= 0)
 121             {
 122               oact->sa_handler = koact.k_sa_handler;
 123               memcpy (&oact->sa_mask, &koact.sa_mask, sizeof (sigset_t));
 124               oact->sa_flags = koact.sa_flags;
 125 # ifdef HAVE_SA_RESTORER
 126               oact->sa_restorer = koact.sa_restorer;
 127 # endif
 128             }
 129           return result;
 130         }
 131
 132 # ifndef __ASSUME_REALTIME_SIGNALS
 133       __set_errno (saved_errno);
 134       __libc_missing_rt_sigs = 1;
 135 # endif
 136     }
 137 #endif
 138
 139 #ifndef __ASSUME_REALTIME_SIGNALS
 140   if (act)
 141     {
 142       k_sigact.k_sa_handler = act->sa_handler;
 143       k_sigact.sa_mask = act->sa_mask.__val[0];
 144       k_sigact.sa_flags = act->sa_flags;
 145 # ifdef HAVE_SA_RESTORER
 146       if (k_sigact.sa_flags & SA_RESTORER)
 147         k_sigact.sa_restorer = act->sa_restorer;
 148       else
 149         {
 150           k_sigact.sa_restorer = choose_restorer (k_sigact.sa_flags);
 151           k_sigact.sa_flags |= SA_RESTORER;
 152         }
 153 # endif
 154     }
 155   result = INLINE_SYSCALL (sigaction, 3, sig,
 156                            act ? __ptrvalue (&k_sigact) : NULL,
 157                            oact ? __ptrvalue (&k_osigact) : NULL);
 158   if (oact && result >= 0)
 159     {
 160       oact->sa_handler = k_osigact.k_sa_handler;
 161       oact->sa_mask.__val[0] = k_osigact.sa_mask;
 162       oact->sa_flags = k_osigact.sa_flags;
 163 # ifdef HAVE_SA_RESTORER
 164       oact->sa_restorer = k_osigact.sa_restorer;
 165 # endif
 166     }
 167   return result;
 168 #endif
 169 }
 170 libc_hidden_def (__libc_sigaction)
 171
 172 #ifdef WRAPPER_INCLUDE
 173 # include WRAPPER_INCLUDE
 174 #endif
 175
 176 #ifndef LIBC_SIGACTION
 177 weak_alias (__libc_sigaction, __sigaction)
 178 libc_hidden_weak (__sigaction)
 179 weak_alias (__libc_sigaction, sigaction)
 180 #endif