src/SDL_fatal.c

/*
  Simple DirectMedia Layer
  Copyright (C) 1997-2011 Sam Lantinga <slouken@libsdl.org>

  This software is provided 'as-is', without any express or implied
  warranty.  In no event will the authors be held liable for any damages
  arising from the use of this software.

  Permission is granted to anyone to use this software for any purpose,
  including commercial applications, and to alter it and redistribute it
  freely, subject to the following restrictions:

  1. The origin of this software must not be misrepresented; you must not
     claim that you wrote the original software. If you use this software
     in a product, an acknowledgment in the product documentation would be
     appreciated but is not required.
  2. Altered source versions must be plainly marked as such, and must not be
     misrepresented as being the original software.
  3. This notice may not be removed or altered from any source distribution.
*/
#include "SDL_config.h"

/* General fatal signal handling code for SDL */

#ifdef HAVE_SIGNAL_H

#include <signal.h>

#include "SDL.h"
#include "SDL_fatal.h"

/* This installs some signal handlers for the more common fatal signals,
   so that if the programmer is lazy, the app doesn't die so horribly if
   the program crashes.
*/

static void
SDL_Parachute(int sig)
{
    signal(sig, SIG_DFL);
    SDL_Quit();
    raise(sig);
}

static const int SDL_fatal_signals[] = {
    SIGSEGV,
#ifdef SIGBUS
    SIGBUS,
#endif
#ifdef SIGFPE
    SIGFPE,
#endif
#ifdef SIGQUIT
    SIGQUIT,
#endif
    0
};

void
SDL_InstallParachute(void)
{
    /* Set a handler for any fatal signal not already handled */
    int i;
#ifdef HAVE_SIGACTION
    struct sigaction action;

    for (i = 0; SDL_fatal_signals[i]; ++i) {
        sigaction(SDL_fatal_signals[i], NULL, &action);
        if (action.sa_handler == SIG_DFL) {
            action.sa_handler = SDL_Parachute;
            sigaction(SDL_fatal_signals[i], &action, NULL);
        }
    }
#ifdef SIGALRM
    /* Set SIGALRM to be ignored -- necessary on Solaris */
    sigaction(SIGALRM, NULL, &action);
    if (action.sa_handler == SIG_DFL) {
        action.sa_handler = SIG_IGN;
        sigaction(SIGALRM, &action, NULL);
    }
#endif
#else
    void (*ohandler) (int);

    for (i = 0; SDL_fatal_signals[i]; ++i) {
        ohandler = signal(SDL_fatal_signals[i], SDL_Parachute);
        if (ohandler != SIG_DFL) {
            signal(SDL_fatal_signals[i], ohandler);
        }
    }
#endif /* HAVE_SIGACTION */
    return;
}

void
SDL_UninstallParachute(void)
{
    /* Remove a handler for any fatal signal handled */
    int i;
#ifdef HAVE_SIGACTION
    struct sigaction action;

    for (i = 0; SDL_fatal_signals[i]; ++i) {
        sigaction(SDL_fatal_signals[i], NULL, &action);
        if (action.sa_handler == SDL_Parachute) {
            action.sa_handler = SIG_DFL;
            sigaction(SDL_fatal_signals[i], &action, NULL);
        }
    }
#else
    void (*ohandler) (int);

    for (i = 0; SDL_fatal_signals[i]; ++i) {
        ohandler = signal(SDL_fatal_signals[i], SIG_DFL);
        if (ohandler != SDL_Parachute) {
            signal(SDL_fatal_signals[i], ohandler);
        }
    }
#endif /* HAVE_SIGACTION */
}

#else

/* No signals on this platform, nothing to do.. */

void
SDL_InstallParachute(void)
{
    return;
}

void
SDL_UninstallParachute(void)
{
    return;
}

#endif /* HAVE_SIGNAL_H */
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