/*
 * selinux.c - Various SELinux related functionality needed for the loader.
 *
 * Jeremy Katz <katzj@redhat.com>
 * 
 * Copyright 2004 Red Hat, Inc.
 * Portions extracted from libselinux which was released as public domain
 *   software by the NSA.
 *
 * This software may be freely redistributed under the terms of the GNU
 * General Public License.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <string.h>

#include "loader.h"
#include "loadermisc.h"
#include "log.h"

static char * getpolicyver() {
    int fd;
    char * buf;

    fd = open("/selinux/policyvers", O_RDONLY);
    if (fd == -1) {
        return NULL;
    }

    buf = malloc(32);
    buf = memset(buf, 0, 32);
    if ((read(fd, buf, 32)) == -1) {
        logMessage("error getting policy version: %s", strerror(errno));
        free(buf);
        close(fd);
        return NULL;
    }

    close(fd);
    return buf;
}

int loadpolicy() {
    char * ver, * fn;
    char *paths[] = { "/tmp/updates/policy.", 
                      "/mnt/source/RHupdates/policy.",
                      "/mnt/runtime/etc/security/selinux/policy.",
                      NULL };
    int i, pid, status;

    ver = getpolicyver();
    if (ver == NULL) {
        return -1;
    }

    fn = malloc(128);
    fn = memset(fn, 0, 128);
    for (i = 0; paths[i]; i++) {
        snprintf(fn, 128, "%s%s", (char *) paths[i], ver);
        if (!access(fn, R_OK)) {
            break;
        }
    }

    if (access(fn, R_OK)) {
        logMessage("Unable to load suitable SELinux policy");
        return -1;
    }

    logMessage("Loading SELinux policy from %s", fn);
    if (!(pid = fork())) {
        setenv("LD_LIBRARY_PATH", LIBPATH, 1);
        execl("/usr/sbin/load_policy", 
              "/usr/sbin/load_policy", fn, NULL);
        logMessage("exec of load_policy failed: %s", strerror(errno));
        exit(1);
    }

    waitpid(pid, &status, 0);
    free(fn);
    if (WIFEXITED(status) && (WEXITSTATUS(status) != 0))
        return 1;

    return 0;
}

/* set a context for execution, from libselinux */
int setexeccon(char * context) {
    int fd;
    ssize_t ret;
    
    fd = open("/proc/self/attr/exec", O_RDWR);
    if (fd < 0)
        return -1;
    if (context) 
        ret = write(fd, context, strlen(context)+1);
    else
        ret = write(fd, NULL, 0); /* clear */
    close(fd);
    if (ret < 0)
        return -1;
    else
        return 0;
}