LXR busybox/libbb/run

   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#if ENABLE_SELINUX
  32#include <selinux/selinux.h>  /* for setexeccon  */
  33#endif
  34
  35#if ENABLE_SELINUX
  36static security_context_t current_sid;
  37
  38void FAST_FUNC renew_current_security_context(void)
  39{
  40        freecon(current_sid);  /* Release old context  */
  41        getcon(&current_sid);  /* update */
  42}
  43void FAST_FUNC set_current_security_context(security_context_t sid)
  44{
  45        freecon(current_sid);  /* Release old context  */
  46        current_sid = sid;
  47}
  48
  49#endif
  50
  51/* Exec SHELL, or DEFAULT_SHELL if SHELL is "" or NULL.
  52 * If ADDITIONAL_ARGS is not NULL, pass them to the shell.
  53 */
  54void FAST_FUNC exec_shell(const char *shell, int loginshell, const char **additional_args)
  55{
  56        const char **args;
  57
  58        args = additional_args;
  59        while (args && *args)
  60                args++;
  61
  62        args = xzalloc(sizeof(args[0]) * (2 + (args - additional_args)));
  63
  64        if (!shell || !shell[0])
  65                shell = DEFAULT_SHELL;
  66
  67        args[0] = bb_get_last_path_component_nostrip(shell);
  68        if (loginshell)
  69                args[0] = xasprintf("-%s", args[0]);
  70        /*args[1] = NULL; - already is */
  71        if (additional_args) {
  72                int cnt = 0;
  73                while (*additional_args)
  74                        args[++cnt] = *additional_args++;
  75        }
  76
  77#if ENABLE_SELINUX
  78        if (current_sid)
  79                setexeccon(current_sid);
  80        if (ENABLE_FEATURE_CLEAN_UP)
  81                freecon(current_sid);
  82#endif
  83        execv(shell, (char **) args);
  84        bb_perror_msg_and_die("can't execute '%s'", shell);
  85}
  86
  87void FAST_FUNC exec_login_shell(const char *shell)
  88{
  89        exec_shell(shell, 1, NULL);
  90}
  91
  92/* Typical idiom for applets which exec *optional* PROG [ARGS] */
  93void FAST_FUNC exec_prog_or_SHELL(char **argv)
  94{
  95        if (argv[0]) {
  96                BB_EXECVP_or_die(argv);
  97        }
  98        /* Both users (nsenter and unshare) do indeed exec
  99         * a _login_ shell (with dash in argv[0])!
 100         */
 101        exec_login_shell(getenv("SHELL"));
 102}
 103