1 /* vi: set sw=4 ts=4: */
3 * Mini sulogin implementation for busybox
5 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
7 //config:config SULOGIN
8 //config: bool "sulogin"
10 //config: select FEATURE_SYSLOG
12 //config: sulogin is invoked when the system goes into single user
13 //config: mode (this is done through an entry in inittab).
15 //applet:IF_SULOGIN(APPLET(sulogin, BB_DIR_SBIN, BB_SUID_DROP))
17 //kbuild:lib-$(CONFIG_SULOGIN) += sulogin.o
19 //usage:#define sulogin_trivial_usage
20 //usage: "[-t N] [TTY]"
21 //usage:#define sulogin_full_usage "\n\n"
22 //usage: "Single user login\n"
23 //usage: "\n -t N Timeout"
28 int sulogin_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
29 int sulogin_main(int argc UNUSED_PARAM, char **argv)
35 /* Note: sulogin is not a suid app. It is meant to be run by init
36 * for single user / emergency mode. init starts it as root.
37 * Normal users (potentially malisious ones) can only run it under
38 * their UID, therefore no paranoia here is warranted:
39 * $LD_LIBRARY_PATH in env, TTY = /dev/sda
40 * are no more dangerous here than in e.g. cp applet.
43 logmode = LOGMODE_BOTH;
44 openlog(applet_name, 0, LOG_AUTH);
46 opt_complementary = "t+"; /* -t N */
47 getopt32(argv, "t:", &timeout);
53 dup(xopen(argv[0], O_RDWR));
60 bb_error_msg_and_die("no password entry for root");
66 r = ask_and_check_password_extended(pwd, timeout,
67 "Give root password for system maintenance\n"
68 "(or type Control-D for normal startup):"
71 /* ^D, ^C, timeout, or read error */
72 bb_error_msg("normal startup");
78 bb_do_delay(LOGIN_FAIL_DELAY);
79 bb_error_msg("Login incorrect");
82 bb_error_msg("starting shell for system maintenance");
84 IF_SELINUX(renew_current_security_context());
86 shell = getenv("SUSHELL");
88 shell = getenv("sushell");
90 shell = pwd->pw_shell;
92 /* Exec login shell with no additional parameters. Never returns. */
93 run_shell(shell, 1, NULL, NULL);