sysdeps/unix/sysv/linux/sparc/sparc32/sigaction.c

   1 /* POSIX.1 sigaction call for Linux/SPARC.
   2    Copyright (C) 1997, 1998 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Miguel de Icaza (miguel@nuclecu.unam.mx), 1997.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Library General Public License as
   8    published by the Free Software Foundation; either version 2 of the
   9    License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Library General Public License for more details.
  15
  16    You should have received a copy of the GNU Library General Public
  17    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  18    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  19    Boston, MA 02111-1307, USA.  */
  20
  21 #include <string.h>
  22 #include <syscall.h>
  23 #include <sys/signal.h>
  24 #include <errno.h>
  25 #include <kernel_sigaction.h>
  26
  27 extern int __syscall_rt_sigaction (int, const struct kernel_sigaction *,
  28                                    struct kernel_sigaction *, unsigned long,
  29                                    size_t);
  30
  31 static void __rt_sigreturn_stub (void);
  32 static void __sigreturn_stub (void);
  33
  34 /* The variable is shared between all wrappers around signal handling
  35    functions which have RT equivalents.  */
  36 int __libc_missing_rt_sigs;
  37
  38 int
  39 __sigaction (int sig, __const struct sigaction *act, struct sigaction *oact)
  40 {
  41   struct old_kernel_sigaction k_sigact, k_osigact;
  42   int ret;
  43
  44   /* First try the RT signals.  */
  45   if (!__libc_missing_rt_sigs)
  46     {
  47       struct kernel_sigaction kact, koact;
  48       unsigned long stub = 0;
  49       int saved_errno = errno;
  50
  51       if (act)
  52         {
  53           kact.k_sa_handler = act->sa_handler;
  54           memcpy (&kact.sa_mask, &act->sa_mask, sizeof (sigset_t));
  55           if (((kact.sa_flags = act->sa_flags) & SA_SIGINFO) != 0)
  56             stub = (unsigned long) &__rt_sigreturn_stub;
  57           else
  58             stub = (unsigned long) &__sigreturn_stub;
  59           stub -= 8;
  60           kact.sa_restorer = NULL;
  61         }
  62
  63       /* XXX The size argument hopefully will have to be changed to the
  64          real size of the user-level sigset_t.  */
  65       ret = __syscall_rt_sigaction (sig, act ? &kact : 0,
  66                                     oact ? &koact : 0,
  67                                     stub, _NSIG / 8);
  68
  69       if (ret >= 0 || errno != ENOSYS)
  70         {
  71           if (oact && ret >= 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               oact->sa_restorer = koact.sa_restorer;
  77             }
  78           return ret;
  79         }
  80
  81       __set_errno (saved_errno);
  82       __libc_missing_rt_sigs = 1;
  83     }
  84
  85   /* Magic to tell the kernel we are using "new-style" signals, in that
  86      the signal table is not kept in userspace.  Not the same as the
  87      really-new-style rt signals.  */
  88   sig = -sig;
  89
  90   if (act)
  91     {
  92       k_sigact.k_sa_handler = act->sa_handler;
  93       k_sigact.sa_mask = act->sa_mask.__val[0];
  94       k_sigact.sa_flags = act->sa_flags;
  95       k_sigact.sa_restorer = NULL;
  96     }
  97
  98   {
  99     register int r_syscallnr __asm__("%g1") = __NR_sigaction;
 100     register int r_sig __asm__("%o0") = sig;
 101     register struct old_kernel_sigaction *r_act __asm__("%o1");
 102     register struct old_kernel_sigaction *r_oact __asm__("%o2");
 103
 104     r_act = act ? &k_sigact : NULL;
 105     r_oact = oact ? &k_osigact : NULL;
 106
 107     __asm__ __volatile__("t 0x10\n\t"
 108                          "bcc 1f\n\t"
 109                          " nop\n\t"
 110                          "sub %%g0,%%o0,%%o0\n"
 111                          "1:"
 112                          : "=r"(r_sig)
 113                          : "r"(r_syscallnr), "r"(r_act), "r"(r_oact),
 114                            "0"(r_sig));
 115
 116     ret = r_sig;
 117   }
 118
 119   if (oact && ret >= 0)
 120     {
 121       oact->sa_handler = k_osigact.k_sa_handler;
 122       oact->sa_mask.__val[0] = k_osigact.sa_mask;
 123       oact->sa_flags = k_osigact.sa_flags;
 124       oact->sa_restorer = NULL;
 125       return ret;
 126     }
 127
 128   __set_errno (-ret);
 129   return -1;
 130 }
 131
 132 weak_alias (__sigaction, sigaction);
 133
 134 static void
 135 __rt_sigreturn_stub (void)
 136 {
 137   __asm__ ("mov %0, %%g1\n\t"
 138            "ta  0x10\n\t"
 139            : /* no outputs */
 140            : "i" (__NR_rt_sigreturn));
 141 }
 142
 143 static void
 144 __sigreturn_stub (void)
 145 {
 146   __asm__ ("mov %0, %%g1\n\t"
 147            "ta  0x10\n\t"
 148            : /* no outputs */
 149            : "i" (__NR_sigreturn));
 150 }