/*
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* Copyright (C) 2007 Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
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*/
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#include <pthread.h>
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#include <signal.h>
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#include <asm/xenomai/syscall.h>
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#include "internal.h"
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#if !HAVE_BACKTRACE
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static inline int backtrace(void **buffer, int size)
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{
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/* Not all *libcs support backtrace(). */
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return 0;
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}
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#else
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#include <execinfo.h>
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#endif
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static struct sigaction sigshadow_action_orig;
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/*
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* The following handler is part of the inner user-interface: should
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* remain extern.
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*/
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int cobalt_sigshadow_handler(int sig, siginfo_t *si, void *ctxt)
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{
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void *frames[SIGSHADOW_BACKTRACE_DEPTH];
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int action, arg, nr, skip;
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if (si->si_code != SI_QUEUE)
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return 0;
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action = sigshadow_action(si->si_int);
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switch (action) {
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case SIGSHADOW_ACTION_HARDEN:
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XENOMAI_SYSCALL1(sc_cobalt_migrate, COBALT_PRIMARY);
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break;
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case SIGSHADOW_ACTION_BACKTRACE:
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arg = sigshadow_arg(si->si_int);
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nr = backtrace(frames, sizeof(frames) / sizeof(frames[0]));
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/* Skip the sighandler context. */
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skip = nr > 3 ? 3 : 0;
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XENOMAI_SYSCALL3(sc_cobalt_backtrace, nr - skip, frames + skip, arg);
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break;
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case SIGSHADOW_ACTION_HOME:
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/*
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* We have been asked to call home from the current
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* context: sending a query for retrieving our handle
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* will just do this.
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*/
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cobalt_get_current_slow();
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break;
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default:
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return 0;
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}
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return 1;
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}
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static void sigshadow_handler(int sig, siginfo_t *si, void *ctxt)
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{
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const struct sigaction *const sa = &sigshadow_action_orig;
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sigset_t saved_sigset;
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if (cobalt_sigshadow_handler(sig, si, ctxt))
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return;
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/* Not a signal sent by the Cobalt core */
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if (((sa->sa_flags & SA_SIGINFO) == 0 && sa->sa_handler == NULL)
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|| ((sa->sa_flags & SA_SIGINFO) && sa->sa_sigaction == NULL))
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return;
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pthread_sigmask(SIG_SETMASK, &sa->sa_mask, &saved_sigset);
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if (!(sa->sa_flags & SA_SIGINFO))
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sa->sa_handler(sig);
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else
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sa->sa_sigaction(sig, si, ctxt);
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pthread_sigmask(SIG_SETMASK, &saved_sigset, NULL);
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}
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static void install_sigshadow(void)
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{
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void *dummy[SIGSHADOW_BACKTRACE_DEPTH];
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struct sigaction new_sigshadow_action;
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sigset_t saved_sigset;
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sigset_t mask_sigset;
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/*
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* Kickstart backtrace() so that it may call malloc() from a
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* safe context right now, not later on from the sigshadow
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* handler.
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*/
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backtrace(dummy, SIGSHADOW_BACKTRACE_DEPTH);
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sigemptyset(&mask_sigset);
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sigaddset(&mask_sigset, SIGSHADOW);
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new_sigshadow_action.sa_flags = SA_SIGINFO | SA_RESTART;
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new_sigshadow_action.sa_sigaction = sigshadow_handler;
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sigemptyset(&new_sigshadow_action.sa_mask);
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pthread_sigmask(SIG_BLOCK, &mask_sigset, &saved_sigset);
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sigaction(SIGSHADOW,
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&new_sigshadow_action, &sigshadow_action_orig);
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if ((sigshadow_action_orig.sa_flags & SA_NODEFER) == 0)
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sigaddset(&sigshadow_action_orig.sa_mask, SIGSHADOW);
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pthread_sigmask(SIG_SETMASK, &saved_sigset, NULL);
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}
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void cobalt_sigshadow_install_once(void)
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{
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static pthread_once_t once = PTHREAD_ONCE_INIT;
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pthread_once(&once, install_sigshadow);
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}
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