busybox/loginutils/sulogin.c
Denys Vlasenko 237bedd499 getopt32: add new syntax of 'o:+' and 'o:*' for -o NUM and -o LIST
In many cases, this aqllows to drop use of opt_complementary.
Approximately -400 bytes:

function                                             old     new   delta
getopt32                                            1423    1502     +79
opt_string                                            17      18      +1
OPT_STR                                               24      25      +1
uniq_main                                            416     406     -10
timeout_main                                         279     269     -10
sulogin_main                                         270     260     -10
readprofile_main                                    1825    1815     -10
ps_main                                              543     533     -10
pidof_main                                           245     235     -10
pgrep_main                                           611     601     -10
od_main                                             2600    2590     -10
mkfs_minix_main                                     2684    2674     -10
mkfs_ext2_main                                      2603    2593     -10
microcom_main                                        712     702     -10
makemime_main                                        315     305     -10
ionice_main                                          282     272     -10
inetd_main                                          2074    2064     -10
ifplugd_main                                        1144    1134     -10
halt_main                                            353     343     -10
getopt_main                                          636     626     -10
fdisk_main                                          2854    2844     -10
env_main                                             206     196     -10
dmesg_main                                           319     309     -10
conspy_main                                         1214    1204     -10
awk_main                                             981     971     -10
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 3/22 up/down: 81/-220)         Total: -139 bytes
   text	   data	    bss	    dec	    hex	filename
 919373	    906	  14060	 934339	  e41c3	busybox_old
 918969	    906	  14060	 933935	  e402f	busybox_unstripped

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2016-07-06 21:58:02 +02:00

94 lines
2.2 KiB
C

/* vi: set sw=4 ts=4: */
/*
* Mini sulogin implementation for busybox
*
* Licensed under GPLv2 or later, see file LICENSE in this source tree.
*/
//config:config SULOGIN
//config: bool "sulogin"
//config: default y
//config: select FEATURE_SYSLOG
//config: help
//config: sulogin is invoked when the system goes into single user
//config: mode (this is done through an entry in inittab).
//applet:IF_SULOGIN(APPLET(sulogin, BB_DIR_SBIN, BB_SUID_DROP))
//kbuild:lib-$(CONFIG_SULOGIN) += sulogin.o
//usage:#define sulogin_trivial_usage
//usage: "[-t N] [TTY]"
//usage:#define sulogin_full_usage "\n\n"
//usage: "Single user login\n"
//usage: "\n -t N Timeout"
#include "libbb.h"
#include <syslog.h>
int sulogin_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int sulogin_main(int argc UNUSED_PARAM, char **argv)
{
int timeout = 0;
struct passwd *pwd;
const char *shell;
/* Note: sulogin is not a suid app. It is meant to be run by init
* for single user / emergency mode. init starts it as root.
* Normal users (potentially malisious ones) can only run it under
* their UID, therefore no paranoia here is warranted:
* $LD_LIBRARY_PATH in env, TTY = /dev/sda
* are no more dangerous here than in e.g. cp applet.
*/
logmode = LOGMODE_BOTH;
openlog(applet_name, 0, LOG_AUTH);
getopt32(argv, "t:+", &timeout);
argv += optind;
if (argv[0]) {
close(0);
close(1);
dup(xopen(argv[0], O_RDWR));
close(2);
dup(0);
}
pwd = getpwuid(0);
if (!pwd) {
bb_error_msg_and_die("no password entry for root");
}
while (1) {
int r;
r = ask_and_check_password_extended(pwd, timeout,
"Give root password for system maintenance\n"
"(or type Control-D for normal startup):"
);
if (r < 0) {
/* ^D, ^C, timeout, or read error */
bb_error_msg("normal startup");
return 0;
}
if (r > 0) {
break;
}
bb_do_delay(LOGIN_FAIL_DELAY);
bb_error_msg("Login incorrect");
}
bb_error_msg("starting shell for system maintenance");
IF_SELINUX(renew_current_security_context());
shell = getenv("SUSHELL");
if (!shell)
shell = getenv("sushell");
if (!shell)
shell = pwd->pw_shell;
/* Exec login shell with no additional parameters. Never returns. */
run_shell(shell, 1, NULL, NULL);
}