LXR busybox/libbb/change

   1/* vi: set sw=4 ts=4: */
   2/*
   3 * Copyright 1989 - 1991, Julianne Frances Haugh <jockgrrl@austin.rr.com>
   4 * All rights reserved.
   5 *
   6 * Redistribution and use in source and binary forms, with or without
   7 * modification, are permitted provided that the following conditions
   8 * are met:
   9 * 1. Redistributions of source code must retain the above copyright
  10 *    notice, this list of conditions and the following disclaimer.
  11 * 2. Redistributions in binary form must reproduce the above copyright
  12 *    notice, this list of conditions and the following disclaimer in the
  13 *    documentation and/or other materials provided with the distribution.
  14 * 3. Neither the name of Julianne F. Haugh nor the names of its contributors
  15 *    may be used to endorse or promote products derived from this software
  16 *    without specific prior written permission.
  17 *
  18 * THIS SOFTWARE IS PROVIDED BY JULIE HAUGH AND CONTRIBUTORS ''AS IS'' AND
  19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  21 * ARE DISCLAIMED.  IN NO EVENT SHALL JULIE HAUGH OR CONTRIBUTORS BE LIABLE
  22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  28 * SUCH DAMAGE.
  29 */
  30#include "libbb.h"
  31
  32/* Become the user and group(s) specified by PW.  */
  33void FAST_FUNC change_identity(const struct passwd *pw)
  34{
  35        int res;
  36
  37        res = initgroups(pw->pw_name, pw->pw_gid);
  38        endgrent(); /* helps to close a fd used internally by libc */
  39
  40        if (res != 0) {
  41                /*
  42                 * If initgroups() fails because a system call is unimplemented
  43                 * then we are running on a Linux kernel compiled without multiuser
  44                 * support (CONFIG_MULTIUSER is not defined).
  45                 *
  46                 * If we are running without multiuser support *and* the target uid
  47                 * already matches the current uid then we can skip the change of
  48                 * identity.
  49                 */
  50                if (errno == ENOSYS && pw->pw_uid == getuid()) {
  51                        return;
  52                }
  53
  54                bb_perror_msg_and_die("can't set groups");
  55        }
  56
  57        xsetgid(pw->pw_gid);
  58        xsetuid(pw->pw_uid);
  59}
  60