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glibc  2.9
Functions | Variables
sigaction.c File Reference
#include <string.h>
#include <syscall.h>
#include <sys/signal.h>
#include <errno.h>
#include <kernel_sigaction.h>
#include <sysdep.h>

Go to the source code of this file.

Functions

static void __rt_sigreturn_stub (void)
static void __sigreturn_stub (void)
int __libc_sigaction (int sig, __const struct sigaction *act, struct sigaction *oact)
 libc_hidden_def (weak_alias(__libc_sigaction)

Variables

int __libc_missing_rt_sigs

Function Documentation

int __libc_sigaction ( int  sig,
__const struct sigaction act,
struct sigaction oact 
)

Definition at line 36 of file sigaction.c.

{
  struct old_kernel_sigaction k_sigact, k_osigact;
  int ret;

#ifdef __NR_rt_sigaction
  /* First try the RT signals.  */
  if (!__libc_missing_rt_sigs)
    {
      struct kernel_sigaction kact, koact;
      unsigned long stub = 0;
      int saved_errno = errno;

      if (act)
       {
         kact.k_sa_handler = act->sa_handler;
         memcpy (&kact.sa_mask, &act->sa_mask, sizeof (sigset_t));
         if (((kact.sa_flags = act->sa_flags) & SA_SIGINFO) != 0)
           stub = (unsigned long) &__rt_sigreturn_stub;
         else
           stub = (unsigned long) &__sigreturn_stub;
         stub -= 8;
         kact.sa_restorer = NULL;
       }

      /* XXX The size argument hopefully will have to be changed to the
        real size of the user-level sigset_t.  */
      ret = INLINE_SYSCALL (rt_sigaction, 5, sig, act ? &kact : 0,
                         oact ? &koact : 0, stub, _NSIG / 8);

      if (ret >= 0 || errno != ENOSYS)
       {
         if (oact && ret >= 0)
           {
             oact->sa_handler = koact.k_sa_handler;
             memcpy (&oact->sa_mask, &koact.sa_mask, sizeof (sigset_t));
             oact->sa_flags = koact.sa_flags;
             oact->sa_restorer = koact.sa_restorer;
           }
         return ret;
       }

      __set_errno (saved_errno);
      __libc_missing_rt_sigs = 1;
    }
#endif

  /* Magic to tell the kernel we are using "new-style" signals, in that
     the signal table is not kept in userspace.  Not the same as the
     really-new-style rt signals.  */
  sig = -sig;

  if (act)
    {
      k_sigact.k_sa_handler = act->sa_handler;
      k_sigact.sa_mask = act->sa_mask.__val[0];
      k_sigact.sa_flags = act->sa_flags;
      k_sigact.sa_restorer = NULL;
    }

  {
    register int r_syscallnr __asm__("%g1") = __NR_sigaction;
    register int r_sig __asm__("%o0") = sig;
    register struct old_kernel_sigaction *r_act __asm__("%o1");
    register struct old_kernel_sigaction *r_oact __asm__("%o2");

    r_act = act ? &k_sigact : NULL;
    r_oact = oact ? &k_osigact : NULL;

    __asm__ __volatile__("t 0x10\n\t"
                      "bcc 1f\n\t"
                      " nop\n\t"
                      "sub %%g0,%%o0,%%o0\n"
                      "1:"
                      : "=r"(r_sig)
                      : "r"(r_syscallnr), "r"(r_act), "r"(r_oact),
                        "0"(r_sig));

    ret = r_sig;
  }

  if (ret >= 0)
    {
      if (oact)
       {
         oact->sa_handler = k_osigact.k_sa_handler;
         oact->sa_mask.__val[0] = k_osigact.sa_mask;
         oact->sa_flags = k_osigact.sa_flags;
         oact->sa_restorer = NULL;
       }
      return ret;
    }

  __set_errno (-ret);
  return -1;
}

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static void __rt_sigreturn_stub ( void  ) [static]

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static void __sigreturn_stub ( void  ) [static]

Definition at line 155 of file sigaction.c.

{
  __asm__ ("mov %0, %%g1\n\t"
          "ta 0x10\n\t"
          : /* no outputs */
          : "i" (__NR_sigreturn));
}

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libc_hidden_def ( weak_alias __libc_sigaction)

Definition at line 133 of file sigaction.c.

{
  __asm__ ("mov %0, %%g1\n\t"
          "ta 0x10\n\t"
          : /* no outputs */
          : "i" (__NR_rt_sigreturn));
}

Variable Documentation

Definition at line 33 of file sigaction.c.