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:/* Needs to be run by root or be suid root - needs to change uid and gid: */
16 //applet:IF_SULOGIN(APPLET(sulogin, BB_DIR_SBIN, BB_SUID_DROP))
18 //kbuild:lib-$(CONFIG_SULOGIN) += sulogin.o
20 //usage:#define sulogin_trivial_usage
21 //usage: "[-t N] [TTY]"
22 //usage:#define sulogin_full_usage "\n\n"
23 //usage: "Single user login\n"
24 //usage: "\n -t N Timeout"
29 int sulogin_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
30 int sulogin_main(int argc UNUSED_PARAM, char **argv)
36 logmode = LOGMODE_BOTH;
37 openlog(applet_name, 0, LOG_AUTH);
39 opt_complementary = "t+"; /* -t N */
40 getopt32(argv, "t:", &timeout);
46 dup(xopen(argv[0], O_RDWR));
51 /* Malicious use like "sulogin /dev/sda"? */
52 if (!isatty(0) || !isatty(1) || !isatty(2)) {
53 logmode = LOGMODE_SYSLOG;
54 bb_error_msg_and_die("not a tty");
57 /* Clear dangerous stuff, set PATH */
58 sanitize_env_if_suid();
68 r = ask_and_check_password_extended(pwd, timeout,
69 "Give root password for system maintenance\n"
70 "(or type Control-D for normal startup):"
73 /* ^D, ^C, timeout, or read error */
74 bb_info_msg("Normal startup");
80 bb_do_delay(LOGIN_FAIL_DELAY);
81 bb_info_msg("Login incorrect");
84 bb_info_msg("System Maintenance Mode");
86 IF_SELINUX(renew_current_security_context());
88 shell = getenv("SUSHELL");
90 shell = getenv("sushell");
92 shell = pwd->pw_shell;
94 /* Exec login shell with no additional parameters. Never returns. */
95 run_shell(shell, 1, NULL, NULL);
98 bb_error_msg_and_die("no password entry for root");