uclibc-ng/libc/sysdeps/linux/arm/sigaction.c

/* Copyright (C) 1997,1998,1999,2000,2002,2003 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, write to the Free
   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   02111-1307 USA.

   Totally hacked up for uClibc by Erik Andersen <andersen@codepoet.org>
   */

#include <errno.h>
#include <signal.h>
#include <string.h>
#include <sys/syscall.h>
#include <bits/kernel_sigaction.h>

#define SA_RESTORER	0x04000000
extern void __default_sa_restorer(void);
extern void __default_rt_sa_restorer(void);

extern __typeof(sigaction) __libc_sigaction;

/* When RT signals are in use we need to use a different return stub.  */
#ifdef __NR_rt_sigreturn
#define choose_restorer(flags)					\
  (flags & SA_SIGINFO) ? __default_rt_sa_restorer		\
  : __default_sa_restorer
#else
#define choose_restorer(flags)					\
  __default_sa_restorer
#endif

#ifdef __NR_rt_sigaction

libc_hidden_proto(memcpy)

/* If ACT is not NULL, change the action for SIG to *ACT.
   If OACT is not NULL, put the old action for SIG in *OACT.  */
int __libc_sigaction (int sig, const struct sigaction *act, struct sigaction *oact)
{
    int result;
    struct kernel_sigaction kact, koact;

    if (act) {
	kact.k_sa_handler = act->sa_handler;
	memcpy (&kact.sa_mask, &act->sa_mask, sizeof (sigset_t));
	kact.sa_flags = act->sa_flags;
# ifdef HAVE_SA_RESTORER
	/* If the user specified SA_ONSTACK this means she is trying to
	   use the old-style stack switching.  Unfortunately this
	   requires the sa_restorer field so we cannot install our own
	   handler.  (In fact the user is likely to be out of luck anyway
	   since the kernel currently only supports stack switching via
	   the X/Open sigaltstack interface, but we allow for the
	   possibility that this might change in the future.)  */
	if (kact.sa_flags & (SA_RESTORER | SA_ONSTACK)) {
	    kact.sa_restorer = act->sa_restorer;
	} else {
	    kact.sa_restorer = choose_restorer (kact.sa_flags);
	    kact.sa_flags |= SA_RESTORER;
	}
# endif
    }

    /* XXX The size argument hopefully will have to be changed to the
       real size of the user-level sigset_t.  */
    result = __syscall_rt_sigaction(sig, act ? __ptrvalue (&kact) : NULL,
	    oact ? __ptrvalue (&koact) : NULL, _NSIG / 8);
    if (oact && result >= 0) {
	oact->sa_handler = koact.k_sa_handler;
	memcpy (&oact->sa_mask, &koact.sa_mask, sizeof (sigset_t));
	oact->sa_flags = koact.sa_flags;
# ifdef HAVE_SA_RESTORER
	oact->sa_restorer = koact.sa_restorer;
# endif
    }
    return result;
}


#else

/* If ACT is not NULL, change the action for SIG to *ACT.
   If OACT is not NULL, put the old action for SIG in *OACT.  */
int __libc_sigaction (int sig, const struct sigaction *act, struct sigaction *oact)
{
    int result;
    struct old_kernel_sigaction kact, koact;

    if (act) {
	kact.k_sa_handler = act->sa_handler;
	kact.sa_mask = act->sa_mask.__val[0];
	kact.sa_flags = act->sa_flags;
# ifdef HAVE_SA_RESTORER
	/* See the comments above for why we test SA_ONSTACK.  */
	if (kact.sa_flags & (SA_RESTORER | SA_ONSTACK)) {
	    kact.sa_restorer = act->sa_restorer;
	} else {
	    kact.sa_restorer = choose_restorer (kact.sa_flags);
	    kact.sa_flags |= SA_RESTORER;
	}
# endif
    }
    result = __syscall_sigaction(sig, act ? __ptrvalue (&kact) : NULL,
	    oact ? __ptrvalue (&koact) : NULL);
    if (oact && result >= 0) {
	oact->sa_handler = koact.k_sa_handler;
	oact->sa_mask.__val[0] = koact.sa_mask;
	oact->sa_flags = koact.sa_flags;
# ifdef HAVE_SA_RESTORER
	oact->sa_restorer = koact.sa_restorer;
# endif
    }
    return result;
}

#endif

#ifndef LIBC_SIGACTION
libc_hidden_proto(sigaction)
weak_alias(__libc_sigaction,sigaction)
libc_hidden_weak(sigaction)
#endif