/* ====================================================================
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 2000-2003 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Apache" and "Apache Software Foundation" must
 *    not be used to endorse or promote products derived from this
 *    software without prior written permission. For written
 *    permission, please contact apache@apache.org.
 *
 * 5. Products derived from this software may not be called "Apache",
 *    nor may "Apache" appear in their name, without prior written
 *    permission of the Apache Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 *
 * Portions of this software are based upon public domain software
 * originally written at the National Center for Supercomputing Applications,
 * University of Illinois, Urbana-Champaign.
 */

/*
 * This file will include OS specific functions which are not inlineable.
 * Any inlineable functions should be defined in os-inline.c instead.
 */

#ifdef _OSD_POSIX

#include "os.h"

#include "httpd.h"
#include "http_config.h"
#include "http_log.h"
#include "apr_lib.h"

#define USER_LEN 8

typedef enum
{
    bs2_unknown,     /* not initialized yet. */
    bs2_noFORK,      /* no fork() because -X flag was specified */
    bs2_FORK,        /* only fork() because uid != 0 */
    bs2_UFORK        /* Normally, ufork() is used to switch identities. */
} bs2_ForkType;

static bs2_ForkType forktype = bs2_unknown;


static void ap_str_toupper(char *str)
{
    while (*str) {
	*str = apr_toupper(*str);
	++str;
    }
}

/* Determine the method for forking off a child in such a way as to
 * set both the POSIX and BS2000 user id's to the unprivileged user.
 */
static bs2_ForkType os_forktype(int one_process)
{
    /* have we checked the OS version before? If yes return the previous
     * result - the OS release isn't going to change suddenly!
     */
    if (forktype == bs2_unknown) {
        /* not initialized yet */

        /* No fork if the one_process option was set */
        if (one_process) {
            forktype = bs2_noFORK;
        }
        /* If the user is unprivileged, use the normal fork() only. */
        else if (getuid() != 0) {
            forktype = bs2_FORK;
        }
        else
            forktype = bs2_UFORK;
    }
    return forktype;
}



/* This routine complements the setuid() call: it causes the BS2000 job
 * environment to be switched to the target user's user id.
 * That is important if CGI scripts try to execute native BS2000 commands.
 */
int os_init_job_environment(server_rec *server, const char *user_name, int one_process)
{
    bs2_ForkType            type = os_forktype(one_process);

    /* We can be sure that no change to uid==0 is possible because of
     * the checks in http_core.c:set_user()
     */

    if (one_process) {

	type = forktype = bs2_noFORK;

	ap_log_error(APLOG_MARK, APLOG_ERR, 0, server,
		     "The debug mode of Apache should only "
		     "be started by an unprivileged user!");
	return 0;
    }

    return 0;
}

/* BS2000 requires a "special" version of fork() before a setuid() call */
pid_t os_fork(const char *user)
{
    pid_t pid;
    char  username[USER_LEN+1];

    switch (os_forktype(0)) {

      case bs2_FORK:
	pid = fork();
	break;

      case bs2_UFORK:
	apr_cpystrn(username, user, sizeof username);

	/* Make user name all upper case - for some versions of ufork() */
	ap_str_toupper(username);

	pid = ufork(username);
	if (pid == -1 && errno == EPERM) {
	    ap_log_error(APLOG_MARK, APLOG_EMERG, errno,
			 NULL, "ufork: Possible mis-configuration "
			 "for user %s - Aborting.", user);
	    exit(1);
	}
	break;

      default:
	pid = 0;
	break;
    }

    return pid;
}

#else /* _OSD_POSIX */
void bs2000_os_is_not_here()
{
}
#endif /* _OSD_POSIX */