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
36 static security_context_t current_sid;
37
renew_current_security_context(void)38 void FAST_FUNC renew_current_security_context(void)
39 {
40 freecon(current_sid); /* Release old context */
41 getcon(¤t_sid); /* update */
42 }
set_current_security_context(security_context_t sid)43 void 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 */
exec_shell(const char * shell,int loginshell,const char ** additional_args)54 void 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
exec_login_shell(const char * shell)87 void 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] */
exec_prog_or_SHELL(char ** argv)93 void 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