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, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #include <errno.h>
  21 #include <signal.h>
  22 #include <string.h>
  23
  24 #include <sysdep.h>
  25 #include <sys/syscall.h>
  26 #include <kernel-features.h>
  27
  28 /* The difference here is that the sigaction structure used in the
  29    kernel is not the same as we use in the libc.  Therefore we must
  30    translate it here.  */
  31 #include <kernel_sigaction.h>
  32
  33 /* The variable is shared between all wrappers around signal handling
  34    functions which have RT equivalents.  */
  35 int __libc_missing_rt_sigs;
  36
  37 #define SA_RESTORER     0x04000000
  38
  39 #ifdef __ARM_EABI__
  40 extern void __default_sa_restorer_v1(void);
  41 extern void __default_sa_restorer_v2(void);
  42 extern void __default_rt_sa_restorer_v1(void);
  43 extern void __default_rt_sa_restorer_v2(void);
  44 # ifdef __ASSUME_SIGFRAME_V2
  45 #  define __default_sa_restorer __default_sa_restorer_v2
  46 #  define __default_rt_sa_restorer __default_rt_sa_restorer_v2
  47 # else
  48 #  include <ldsodefs.h>
  49 #  define __default_sa_restorer (GLRO(dl_osversion) >= 0x020612 \
  50                                  ? __default_sa_restorer_v2     \
  51                                  : __default_sa_restorer_v1)
  52 #  define __default_rt_sa_restorer (GLRO(dl_osversion) >= 0x020612      \
  53                                     ? __default_rt_sa_restorer_v2       \
  54                                     : __default_rt_sa_restorer_v1)
  55 # endif
  56 #else
  57 extern void __default_sa_restorer(void);
  58 extern void __default_rt_sa_restorer(void);
  59 #endif
  60
  61 /* When RT signals are in use we need to use a different return stub.  */
  62 #ifdef __NR_rt_sigreturn
  63 #define choose_restorer(flags)                                  \
  64   (flags & SA_SIGINFO) ? __default_rt_sa_restorer               \
  65   : __default_sa_restorer
  66 #else
  67 #define choose_restorer(flags)                                  \
  68   __default_sa_restorer
  69 #endif
  70
  71 /* If ACT is not NULL, change the action for SIG to *ACT.
  72    If OACT is not NULL, put the old action for SIG in *OACT.  */
  73 int
  74 __libc_sigaction (sig, act, oact)
  75      int sig;
  76      const struct sigaction *act;
  77      struct sigaction *oact;
  78 {
  79 #ifndef __ASSUME_REALTIME_SIGNALS
  80   struct old_kernel_sigaction k_sigact, k_osigact;
  81 #endif
  82   int result;
  83
  84 #ifdef __NR_rt_sigaction
  85   /* First try the RT signals.  */
  86 # ifndef __ASSUME_REALTIME_SIGNALS
  87   if (!__libc_missing_rt_sigs)
  88 # endif
  89     {
  90       struct kernel_sigaction kact, koact;
  91 # ifndef __ASSUME_REALTIME_SIGNALS
  92       int saved_errno = errno;
  93 # endif
  94
  95       if (act)
  96         {
  97           kact.k_sa_handler = act->sa_handler;
  98           memcpy (&kact.sa_mask, &act->sa_mask, sizeof (sigset_t));
  99           kact.sa_flags = act->sa_flags;
 100 # ifdef HAVE_SA_RESTORER
 101           if (kact.sa_flags & SA_RESTORER)
 102             kact.sa_restorer = act->sa_restorer;
 103           else
 104             {
 105               kact.sa_restorer = choose_restorer (kact.sa_flags);
 106               kact.sa_flags |= SA_RESTORER;
 107             }
 108 # endif
 109         }
 110
 111       /* XXX The size argument hopefully will have to be changed to the
 112          real size of the user-level sigset_t.  */
 113       result = INLINE_SYSCALL (rt_sigaction, 4, sig,
 114                                act ? __ptrvalue (&kact) : NULL,
 115                                oact ? __ptrvalue (&koact) : NULL, _NSIG / 8);
 116
 117 # ifndef __ASSUME_REALTIME_SIGNALS
 118       if (result >= 0 || errno != ENOSYS)
 119 # endif
 120         {
 121           if (oact && result >= 0)
 122             {
 123               oact->sa_handler = koact.k_sa_handler;
 124               memcpy (&oact->sa_mask, &koact.sa_mask, sizeof (sigset_t));
 125               oact->sa_flags = koact.sa_flags;
 126 # ifdef HAVE_SA_RESTORER
 127               oact->sa_restorer = koact.sa_restorer;
 128 # endif
 129             }
 130           return result;
 131         }
 132
 133 # ifndef __ASSUME_REALTIME_SIGNALS
 134       __set_errno (saved_errno);
 135       __libc_missing_rt_sigs = 1;
 136 # endif
 137     }
 138 #endif
 139
 140 #ifndef __ASSUME_REALTIME_SIGNALS
 141   if (act)
 142     {
 143       k_sigact.k_sa_handler = act->sa_handler;
 144       k_sigact.sa_mask = act->sa_mask.__val[0];
 145       k_sigact.sa_flags = act->sa_flags;
 146 # ifdef HAVE_SA_RESTORER
 147       if (k_sigact.sa_flags & SA_RESTORER)
 148         k_sigact.sa_restorer = act->sa_restorer;
 149       else
 150         {
 151           k_sigact.sa_restorer = choose_restorer (k_sigact.sa_flags);
 152           k_sigact.sa_flags |= SA_RESTORER;
 153         }
 154 # endif
 155     }
 156   result = INLINE_SYSCALL (sigaction, 3, sig,
 157                            act ? __ptrvalue (&k_sigact) : NULL,
 158                            oact ? __ptrvalue (&k_osigact) : NULL);
 159   if (oact && result >= 0)
 160     {
 161       oact->sa_handler = k_osigact.k_sa_handler;
 162       oact->sa_mask.__val[0] = k_osigact.sa_mask;
 163       oact->sa_flags = k_osigact.sa_flags;
 164 # ifdef HAVE_SA_RESTORER
 165       oact->sa_restorer = k_osigact.sa_restorer;
 166 # endif
 167     }
 168   return result;
 169 #endif
 170 }
 171 libc_hidden_def (__libc_sigaction)
 172
 173 #ifdef WRAPPER_INCLUDE
 174 # include WRAPPER_INCLUDE
 175 #endif
 176
 177 #ifndef LIBC_SIGACTION
 178 weak_alias (__libc_sigaction, __sigaction)
 179 libc_hidden_weak (__sigaction)
 180 weak_alias (__libc_sigaction, sigaction)
 181 #endif