/*
 * auditd.c: This is a simple audit daemon that throws all messages away.
 *
 * Copyright (C) 2006  Red Hat, Inc.  All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#define _GNU_SOURCE 1

#include "config.h"

#include <sys/types.h>
#include <sys/syscall.h>
#include <sys/poll.h>
#include <unistd.h>
#include <fcntl.h>
#include <signal.h>
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <errno.h>

#include <libaudit.h>

#include "auditd.h"

static int done;

static void sig_done(int sig)
{
    done = 1;
}

static void do_auditd(int fd) {
    struct audit_reply rep;
    sigset_t sigs;
    struct sigaction sa;
    struct pollfd pds = {
        .events = POLLIN,
        .revents = 0,
        .fd = fd,
    };

    if (audit_set_pid(fd, getpid(), WAIT_YES) < 0)
        return;

    if (audit_set_enabled(fd, 1) < 0)
        return;

    memset(&sa, '\0', sizeof (sa));
    sa.sa_handler = sig_done;
    sigaction(SIGTERM, &sa, NULL);
    sigaction(SIGINT, &sa, NULL);
    sigaction(SIGHUP, &sa, NULL);

    sigfillset(&sigs);
    sigdelset(&sigs, SIGTERM);
    sigdelset(&sigs, SIGINT);
    sigdelset(&sigs, SIGHUP);

    while (1) {
        int retval;

        memset(&rep, 0, sizeof(rep));

        do {
            retval = ppoll(&pds, 1, NULL, &sigs);
        } while (retval == -1 && errno == EINTR && !done);

        if (done)
            break;

        if (audit_get_reply(fd, &rep, GET_REPLY_NONBLOCKING, 0) > 0) {
            /* we don't actually want to do anything here. */
            ;
        }
    }
    return;
}

int audit_daemonize(void) {
    int fd;
    pid_t child;

/* I guess we should actually do something with the output of AC_FUNC_FORK */
#ifndef HAVE_WORKING_FORK
#error "Autoconf could not find a working fork. Please fix this."
#endif

    if ((child = fork()) > 0)
        return 0;

    if (child < 0)
        return -1;

    /* Close stdin and friends */
    close(STDIN_FILENO);
    close(STDOUT_FILENO);
    close(STDERR_FILENO);

    if ((fd = open("/proc/self/oom_score_adj", O_RDWR)) >= 0) {
        write(fd, "-1000", 5);
        close(fd);
    }
    fd = audit_open();
    do_auditd(fd);
    audit_close(fd);

    return 0;
}

int main(void) {
    if (audit_daemonize() < 0)
    {
        perror("fork");
        return 1;
    }

    return 0;
}

/*
 * vim:ts=8:sw=4:sts=4:et
 */