source: MondoRescue/branches/stable/mindi-busybox/loginutils/sulogin.c@ 902

/* vi: set sw=4 ts=4: */
#include <fcntl.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include <unistd.h>
#include <utmp.h>
#include <sys/resource.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <ctype.h>
#include <time.h>

#include "busybox.h"


#define SULOGIN_PROMPT "\nGive root password for system maintenance\n" \
    "(or type Control-D for normal startup):"

static const char * const forbid[] = {
    "ENV",
    "BASH_ENV",
    "HOME",
    "IFS",
    "PATH",
    "SHELL",
    "LD_LIBRARY_PATH",
    "LD_PRELOAD",
    "LD_TRACE_LOADED_OBJECTS",
    "LD_BIND_NOW",
    "LD_AOUT_LIBRARY_PATH",
    "LD_AOUT_PRELOAD",
    "LD_NOWARN",
    "LD_KEEPDIR",
    (char *) 0
};



static void catchalarm(int ATTRIBUTE_UNUSED junk)
{
    exit(EXIT_FAILURE);
}


int sulogin_main(int argc, char **argv)
{
    char *cp;
    char *device = NULL;
    const char *name = "root";
    int timeout = 0;

#define pass bb_common_bufsiz1

    struct passwd pwent;
    struct passwd *pwd;
    const char * const *p;
#if ENABLE_FEATURE_SHADOWPASSWDS
    struct spwd *spwd = NULL;
#endif

    openlog("sulogin", LOG_PID | LOG_CONS | LOG_NOWAIT, LOG_AUTH);
    if (argc > 1) {
        if (strncmp(argv[1], "-t", 2) == 0) {
            if (argv[1][2] == '\0') { /* -t NN */
                if (argc > 2) {
                    timeout = atoi(argv[2]);
                    if (argc > 3) {
                        device = argv[3];
                    }
                }
            } else { /* -tNNN */
                timeout = atoi(&argv[1][2]);
                if (argc > 2) {
                    device = argv[2];
                }
            }
        } else {
            device = argv[1];
        }
        if (device) {
            close(0);
            close(1);
            close(2);
            if (open(device, O_RDWR) == 0) {
                dup(0);
                dup(0);
            } else {
                syslog(LOG_WARNING, "cannot open %s\n", device);
                exit(EXIT_FAILURE);
            }
        }
    }
    if (access(bb_path_passwd_file, 0) == -1) {
        syslog(LOG_WARNING, "No password file\n");
        bb_error_msg_and_die("No password file\n");
    }
    if (!isatty(0) || !isatty(1) || !isatty(2)) {
        exit(EXIT_FAILURE);
    }


    /* Clear out anything dangerous from the environment */
    for (p = forbid; *p; p++)
        unsetenv(*p);


    signal(SIGALRM, catchalarm);
    if (!(pwd = getpwnam(name))) {
        syslog(LOG_WARNING, "No password entry for `root'\n");
        bb_error_msg_and_die("No password entry for `root'\n");
    }
    pwent = *pwd;
#if ENABLE_FEATURE_SHADOWPASSWDS
    spwd = NULL;
    if (pwd && ((strcmp(pwd->pw_passwd, "x") == 0)
                || (strcmp(pwd->pw_passwd, "*") == 0))) {
        endspent();
        spwd = getspnam(name);
        if (spwd) {
            pwent.pw_passwd = spwd->sp_pwdp;
        }
    }
#endif
    while (1) {
        cp = bb_askpass(timeout, SULOGIN_PROMPT);
        if (!cp || !*cp) {
            puts("\n");
            fflush(stdout);
            syslog(LOG_INFO, "Normal startup\n");
            exit(EXIT_SUCCESS);
        } else {
            safe_strncpy(pass, cp, sizeof(pass));
            memset(cp, 0, strlen(cp));
        }
        if (strcmp(pw_encrypt(pass, pwent.pw_passwd), pwent.pw_passwd) == 0) {
            break;
        }
        bb_do_delay(FAIL_DELAY);
        puts("Login incorrect");
        fflush(stdout);
        syslog(LOG_WARNING, "Incorrect root password\n");
    }
    memset(pass, 0, strlen(pass));
    signal(SIGALRM, SIG_DFL);
    puts("Entering System Maintenance Mode\n");
    fflush(stdout);
    syslog(LOG_INFO, "System Maintenance Mode\n");

#if ENABLE_SELINUX
    renew_current_security_context();
#endif

    run_shell(pwent.pw_shell, 1, 0, 0);

    return (0);
}