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 #ifdef __NR_rt_sigaction
  45   /* First try the RT signals.  */
  46   if (!__libc_missing_rt_sigs)
  47     {
  48       struct kernel_sigaction kact, koact;
  49       unsigned long stub = 0;
  50       int saved_errno = errno;
  51
  52       if (act)
  53         {
  54           kact.k_sa_handler = act->sa_handler;
  55           memcpy (&kact.sa_mask, &act->sa_mask, sizeof (sigset_t));
  56           if (((kact.sa_flags = act->sa_flags) & SA_SIGINFO) != 0)
  57             stub = (unsigned long) &__rt_sigreturn_stub;
  58           else
  59             stub = (unsigned long) &__sigreturn_stub;
  60           stub -= 8;
  61           kact.sa_restorer = NULL;
  62         }
  63
  64       /* XXX The size argument hopefully will have to be changed to the
  65          real size of the user-level sigset_t.  */
  66       ret = __syscall_rt_sigaction (sig, act ? &kact : 0,
  67                                     oact ? &koact : 0,
  68                                     stub, _NSIG / 8);
  69
  70       if (ret >= 0 || errno != ENOSYS)
  71         {
  72           if (oact && ret >= 0)
  73             {
  74               oact->sa_handler = koact.k_sa_handler;
  75               memcpy (&oact->sa_mask, &koact.sa_mask, sizeof (sigset_t));
  76               oact->sa_flags = koact.sa_flags;
  77               oact->sa_restorer = koact.sa_restorer;
  78             }
  79           return ret;
  80         }
  81
  82       __set_errno (saved_errno);
  83       __libc_missing_rt_sigs = 1;
  84     }
  85 #endif
  86
  87   /* Magic to tell the kernel we are using "new-style" signals, in that
  88      the signal table is not kept in userspace.  Not the same as the
  89      really-new-style rt signals.  */
  90   sig = -sig;
  91
  92   if (act)
  93     {
  94       k_sigact.k_sa_handler = act->sa_handler;
  95       k_sigact.sa_mask = act->sa_mask.__val[0];
  96       k_sigact.sa_flags = act->sa_flags;
  97       k_sigact.sa_restorer = NULL;
  98     }
  99
 100   {
 101     register int r_syscallnr __asm__("%g1") = __NR_sigaction;
 102     register int r_sig __asm__("%o0") = sig;
 103     register struct old_kernel_sigaction *r_act __asm__("%o1");
 104     register struct old_kernel_sigaction *r_oact __asm__("%o2");
 105
 106     r_act = act ? &k_sigact : NULL;
 107     r_oact = oact ? &k_osigact : NULL;
 108
 109     __asm__ __volatile__("t 0x10\n\t"
 110                          "bcc 1f\n\t"
 111                          " nop\n\t"
 112                          "sub %%g0,%%o0,%%o0\n"
 113                          "1:"
 114                          : "=r"(r_sig)
 115                          : "r"(r_syscallnr), "r"(r_act), "r"(r_oact),
 116                            "0"(r_sig));
 117
 118     ret = r_sig;
 119   }
 120
 121   if (oact && ret >= 0)
 122     {
 123       oact->sa_handler = k_osigact.k_sa_handler;
 124       oact->sa_mask.__val[0] = k_osigact.sa_mask;
 125       oact->sa_flags = k_osigact.sa_flags;
 126       oact->sa_restorer = NULL;
 127       return ret;
 128     }
 129
 130   __set_errno (-ret);
 131   return -1;
 132 }
 133
 134 weak_alias (__sigaction, sigaction);
 135
 136 static void
 137 __rt_sigreturn_stub (void)
 138 {
 139   __asm__ ("mov %0, %%g1\n\t"
 140            "ta  0x10\n\t"
 141            : /* no outputs */
 142            : "i" (__NR_rt_sigreturn));
 143 }
 144
 145 static void
 146 __sigreturn_stub (void)
 147 {
 148   __asm__ ("mov %0, %%g1\n\t"
 149            "ta  0x10\n\t"
 150            : /* no outputs */
 151            : "i" (__NR_sigreturn));
 152 }