login: make it saner and smaller by ~0.5k.
This commit is contained in:
Denis Vlasenko
parent
6bbd174593
commit
9a9edf200b
@ -29,59 +29,59 @@
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#ifdef CONFIG_FEATURE_UTMP
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// import from utmp.c
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static void checkutmp(int picky);
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static void setutmp(const char *name, const char *line);
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/* Stuff global to this file */
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static struct utmp utent;
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static void read_or_build_utent(int picky);
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static void write_utent(const char *username);
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#endif
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enum {
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TIMEOUT = 60,
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EMPTY_USERNAME_COUNT = 10,
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USERNAME_SIZE = 32,
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TTYNAME_SIZE = 32,
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};
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static int check_nologin(int amroot);
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static void die_if_nologin_and_non_root(int amroot);
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#if defined CONFIG_FEATURE_SECURETTY
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static int check_tty(const char *tty);
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static int check_securetty(void);
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#else
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static inline int check_tty(const char *tty) { return 1; }
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static inline int check_securetty(void) { return 1; }
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#endif
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static int is_my_tty(const char *tty);
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static int login_prompt(char *buf_name);
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static int is_my_tty(void);
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static void get_username_or_die(char *buf, int size_buf);
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static void motd(void);
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static void alarm_handler(int sig ATTRIBUTE_UNUSED)
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{
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fprintf(stderr, "\r\nLogin timed out after %s seconds\r\n", TIMEOUT);
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fprintf(stderr, "\r\nLogin timed out after %d seconds\r\n", TIMEOUT);
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exit(EXIT_SUCCESS);
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}
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static char full_tty[TTYNAME_SIZE];
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static char* short_tty = full_tty;
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int login_main(int argc, char **argv)
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{
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char tty[BUFSIZ];
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char full_tty[200];
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char fromhost[512];
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char username[USERNAME_SIZE];
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const char *tmp;
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int amroot;
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int flag;
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int failed;
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int count = 0;
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struct passwd *pw, pw_copy;
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struct passwd *pw;
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#ifdef CONFIG_WHEEL_GROUP
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struct group *grp;
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#endif
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int opt_preserve = 0;
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int opt_fflag = 0;
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char *opt_host = 0;
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int alarmstarted = 0;
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#ifdef CONFIG_SELINUX
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security_context_t user_sid = NULL;
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#endif
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@ -90,7 +90,6 @@ int login_main(int argc, char **argv)
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amroot = (getuid() == 0);
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signal(SIGALRM, alarm_handler);
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alarm(TIMEOUT);
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alarmstarted = 1;
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while ((flag = getopt(argc, argv, "f:h:p")) != EOF) {
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switch (flag) {
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@ -105,10 +104,10 @@ int login_main(int argc, char **argv)
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if (optarg != argv[optind-1])
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bb_show_usage();
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if (!amroot) /* Auth bypass only if real UID is zero */
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bb_error_msg_and_die("-f permission denied");
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if (!amroot) /* Auth bypass only if real UID is zero */
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bb_error_msg_and_die("-f is for root only");
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safe_strncpy(username, optarg, USERNAME_SIZE);
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safe_strncpy(username, optarg, sizeof(username));
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opt_fflag = 1;
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break;
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case 'h':
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@ -118,113 +117,83 @@ int login_main(int argc, char **argv)
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bb_show_usage();
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}
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}
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if (optind < argc) /* user from command line (getty) */
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safe_strncpy(username, argv[optind], USERNAME_SIZE);
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safe_strncpy(username, argv[optind], sizeof(username));
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/* Let's find out and memorize our tty */
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if (!isatty(0) || !isatty(1) || !isatty(2))
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return EXIT_FAILURE; /* Must be a terminal */
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#ifdef CONFIG_FEATURE_UTMP
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checkutmp(!amroot);
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#endif
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safe_strncpy(full_tty, "UNKNOWN", sizeof(full_tty));
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tmp = ttyname(0);
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if (tmp && (strncmp(tmp, "/dev/", 5) == 0))
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safe_strncpy(tty, tmp + 5, sizeof(tty));
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else if (tmp && *tmp == '/')
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safe_strncpy(tty, tmp, sizeof(tty));
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else
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safe_strncpy(tty, "UNKNOWN", sizeof(tty));
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if (tmp) {
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safe_strncpy(full_tty, tmp, sizeof(full_tty));
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if (strncmp(full_tty, "/dev/", 5) == 0)
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short_tty = full_tty + 5;
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}
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#ifdef CONFIG_FEATURE_UTMP
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if (amroot)
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memset(utent.ut_host, 0, sizeof(utent.ut_host));
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#endif
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if (ENABLE_FEATURE_UTMP) {
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read_or_build_utent(!amroot);
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if (amroot)
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memset(utent.ut_host, 0, sizeof(utent.ut_host));
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}
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if (opt_host) {
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#ifdef CONFIG_FEATURE_UTMP
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safe_strncpy(utent.ut_host, opt_host, sizeof(utent.ut_host));
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#endif
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if (ENABLE_FEATURE_UTMP)
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safe_strncpy(utent.ut_host, opt_host, sizeof(utent.ut_host));
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snprintf(fromhost, sizeof(fromhost)-1, " on `%.100s' from "
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"`%.200s'", tty, opt_host);
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"`%.200s'", short_tty, opt_host);
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}
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else
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snprintf(fromhost, sizeof(fromhost)-1, " on `%.100s'", tty);
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snprintf(fromhost, sizeof(fromhost)-1, " on `%.100s'", short_tty);
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bb_setpgrp;
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openlog(bb_applet_name, LOG_PID | LOG_CONS | LOG_NOWAIT, LOG_AUTH);
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while (1) {
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failed = 0;
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if (!username[0])
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if (!login_prompt(username))
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return EXIT_FAILURE;
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if (!alarmstarted && (TIMEOUT > 0)) {
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alarm(TIMEOUT);
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alarmstarted = 1;
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}
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get_username_or_die(username, sizeof(username));
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pw = getpwnam(username);
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if (!pw) {
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pw_copy.pw_name = "UNKNOWN";
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pw_copy.pw_passwd = "!";
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opt_fflag = 0;
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failed = 1;
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} else
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pw_copy = *pw;
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pw = &pw_copy;
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if ((pw->pw_passwd[0] == '!') || (pw->pw_passwd[0] == '*'))
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failed = 1;
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if (opt_fflag) {
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opt_fflag = 0;
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goto auth_ok;
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safe_strncpy(username, "UNKNOWN", sizeof(username));
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goto auth_failed;
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}
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if (!failed && (pw->pw_uid == 0) && (!check_tty(tty)))
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failed = 1;
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if (pw->pw_passwd[0] == '!' || pw->pw_passwd[0] == '*')
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goto auth_failed;
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if (opt_fflag)
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break; /* -f USER: success without asking passwd */
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if (pw->pw_uid == 0 && !check_securetty())
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goto auth_failed;
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/* Don't check the password if password entry is empty (!) */
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if (!pw->pw_passwd[0])
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goto auth_ok;
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break;
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/* authorization takes place here */
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if (correct_password(pw))
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goto auth_ok;
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failed = 1;
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auth_ok:
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if (!failed)
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break;
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break;
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auth_failed:
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opt_fflag = 0;
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bb_do_delay(FAIL_DELAY);
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puts("Login incorrect");
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username[0] = 0;
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if (++count == 3) {
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syslog(LOG_WARNING, "invalid password for `%s'%s", pw->pw_name, fromhost);
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syslog(LOG_WARNING, "invalid password for `%s'%s",
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username, fromhost);
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return EXIT_FAILURE;
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}
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username[0] = '\0';
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}
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alarm(0);
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if (check_nologin(pw->pw_uid == 0))
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return EXIT_FAILURE;
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die_if_nologin_and_non_root(pw->pw_uid == 0);
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#ifdef CONFIG_FEATURE_UTMP
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setutmp(username, tty);
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#endif
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if (*tty != '/')
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snprintf(full_tty, sizeof(full_tty)-1, "/dev/%s", tty);
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else
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safe_strncpy(full_tty, tty, sizeof(full_tty)-1);
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if (ENABLE_FEATURE_UTMP)
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write_utent(username);
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#ifdef CONFIG_SELINUX
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if (is_selinux_enabled()) {
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@ -249,7 +218,7 @@ auth_ok:
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}
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}
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#endif
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if (!is_my_tty(full_tty))
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if (!is_my_tty())
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syslog(LOG_ERR, "unable to determine TTY name, got %s", full_tty);
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/* Try these, but don't complain if they fail
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@ -300,96 +269,91 @@ auth_ok:
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}
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static int login_prompt(char *buf_name)
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static void get_username_or_die(char *buf, int size_buf)
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{
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char buf[1024];
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char *sp, *ep;
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int i;
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int c, cntdown;
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cntdown = EMPTY_USERNAME_COUNT;
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prompt:
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/* skip whitespace */
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print_login_prompt();
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do {
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c = getchar();
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if (c == EOF) exit(1);
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if (c == '\n') {
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if (!--cntdown) exit(1);
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goto prompt;
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}
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} while (isspace(c));
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for (i=0; i<EMPTY_USERNAME_COUNT; i++) {
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print_login_prompt();
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if (!fgets(buf, sizeof(buf)-1, stdin))
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return 0;
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if (!strchr(buf, '\n'))
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return 0;
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for (sp = buf; isspace(*sp); sp++) { }
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for (ep = sp; isgraph(*ep); ep++) { }
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*ep = '\0';
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safe_strncpy(buf_name, sp, USERNAME_SIZE);
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if (buf_name[0])
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return 1;
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}
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return 0;
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*buf++ = c;
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if (!fgets(buf, size_buf-2, stdin))
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exit(1);
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if (!strchr(buf, '\n'))
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exit(1);
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while (isgraph(*buf)) buf++;
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*buf = '\0';
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}
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static int check_nologin(int amroot)
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static void die_if_nologin_and_non_root(int amroot)
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{
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if (access(bb_path_nologin_file, F_OK) == 0) {
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FILE *fp;
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int c;
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FILE *fp;
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int c;
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fp = fopen(bb_path_nologin_file, "r");
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if (fp) {
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while ((c = getc(fp)) != EOF)
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putchar((c=='\n') ? '\r' : c);
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if (access(bb_path_nologin_file, F_OK))
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return;
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fflush(stdout);
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fclose(fp);
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} else {
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puts("\r\nSystem closed for routine maintenance.\r");
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}
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if (!amroot)
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return 1;
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puts("\r\n[Disconnect bypassed -- root login allowed.]\r");
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}
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return 0;
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fp = fopen(bb_path_nologin_file, "r");
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if (fp) {
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while ((c = getc(fp)) != EOF)
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putchar((c=='\n') ? '\r' : c);
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fflush(stdout);
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fclose(fp);
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} else
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puts("\r\nSystem closed for routine maintenance\r");
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if (!amroot)
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exit(1);
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puts("\r\n[Disconnect bypassed -- root login allowed.]\r");
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}
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#ifdef CONFIG_FEATURE_SECURETTY
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static int check_tty(const char *tty)
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static int check_securetty(void)
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{
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FILE *fp;
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int i;
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char buf[BUFSIZ];
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fp = fopen(bb_path_securetty_file, "r");
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if (fp) {
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while (fgets(buf, sizeof(buf)-1, fp)) {
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for(i = strlen(buf)-1; i>=0; --i) {
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if (!isspace(buf[i]))
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break;
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}
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buf[++i] = '\0';
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if ((buf[0]=='\0') || (buf[0]=='#'))
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continue;
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if (strcmp(buf, tty)== 0) {
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fclose(fp);
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return 1;
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}
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}
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fclose(fp);
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return 0;
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if (!fp) {
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/* A missing securetty file is not an error. */
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return 1;
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}
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/* A missing securetty file is not an error. */
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return 1;
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while (fgets(buf, sizeof(buf)-1, fp)) {
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for(i = strlen(buf)-1; i>=0; --i) {
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if (!isspace(buf[i]))
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break;
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}
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buf[++i] = '\0';
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if ((buf[0]=='\0') || (buf[0]=='#'))
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continue;
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if (strcmp(buf, short_tty) == 0) {
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fclose(fp);
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return 1;
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}
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}
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fclose(fp);
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return 0;
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}
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#endif
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/* returns 1 if true */
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static int is_my_tty(const char *tty)
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static int is_my_tty(void)
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{
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struct stat by_name, by_fd;
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if (stat(tty, &by_name) || fstat(0, &by_fd))
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if (stat(full_tty, &by_name) || fstat(0, &by_fd))
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return 0;
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if (by_name.st_rdev != by_fd.st_rdev)
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@ -414,15 +378,10 @@ static void motd(void)
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#ifdef CONFIG_FEATURE_UTMP
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// vv Taken from tinylogin utmp.c vv
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#define NO_UTENT \
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"No utmp entry. You must exec \"login\" from the lowest level \"sh\""
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#define NO_TTY \
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"Unable to determine your tty name."
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/* vv Taken from tinylogin utmp.c vv */
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/*
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* checkutmp - see if utmp file is correct for this process
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* read_or_build_utent - see if utmp file is correct for this process
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*
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* System V is very picky about the contents of the utmp file
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* and requires that a slot for the current process exist.
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@ -435,9 +394,8 @@ static void motd(void)
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* command line flags.
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*/
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static void checkutmp(int picky)
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static void read_or_build_utent(int picky)
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{
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char *line;
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struct utmp *ut;
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pid_t pid = getpid();
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@ -446,53 +404,41 @@ static void checkutmp(int picky)
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/* First, try to find a valid utmp entry for this process. */
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while ((ut = getutent()))
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if (ut->ut_pid == pid && ut->ut_line[0] && ut->ut_id[0] &&
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(ut->ut_type == LOGIN_PROCESS || ut->ut_type == USER_PROCESS))
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(ut->ut_type == LOGIN_PROCESS || ut->ut_type == USER_PROCESS))
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break;
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/* If there is one, just use it, otherwise create a new one. */
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if (ut) {
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utent = *ut;
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} else {
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time_t t_tmp;
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if (picky) {
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puts(NO_UTENT);
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exit(1);
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}
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line = ttyname(0);
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if (!line) {
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puts(NO_TTY);
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exit(1);
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}
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if (strncmp(line, "/dev/", 5) == 0)
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line += 5;
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if (picky)
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bb_error_msg_and_die("no utmp entry found");
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memset(&utent, 0, sizeof(utent));
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utent.ut_type = LOGIN_PROCESS;
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utent.ut_pid = pid;
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strncpy(utent.ut_line, line, sizeof(utent.ut_line));
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/* XXX - assumes /dev/tty?? */
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strncpy(utent.ut_id, utent.ut_line + 3, sizeof(utent.ut_id));
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strncpy(utent.ut_line, short_tty, sizeof(utent.ut_line));
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/* This one is only 4 chars wide. Try to fit something
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* remotely meaningful by skipping "tty"... */
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strncpy(utent.ut_id, short_tty + 3, sizeof(utent.ut_id));
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strncpy(utent.ut_user, "LOGIN", sizeof(utent.ut_user));
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t_tmp = (time_t)utent.ut_time;
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time(&t_tmp);
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utent.ut_time = time(NULL);
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}
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}
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/*
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* setutmp - put a USER_PROCESS entry in the utmp file
|
||||
* write_utent - put a USER_PROCESS entry in the utmp file
|
||||
*
|
||||
* setutmp changes the type of the current utmp entry to
|
||||
* write_utent changes the type of the current utmp entry to
|
||||
* USER_PROCESS. the wtmp file will be updated as well.
|
||||
*/
|
||||
|
||||
static void setutmp(const char *name, const char *line ATTRIBUTE_UNUSED)
|
||||
static void write_utent(const char *username)
|
||||
{
|
||||
time_t t_tmp = (time_t)utent.ut_time;
|
||||
|
||||
utent.ut_type = USER_PROCESS;
|
||||
strncpy(utent.ut_user, name, sizeof(utent.ut_user));
|
||||
time(&t_tmp);
|
||||
/* other fields already filled in by checkutmp above */
|
||||
strncpy(utent.ut_user, username, sizeof(utent.ut_user));
|
||||
utent.ut_time = time(NULL);
|
||||
/* other fields already filled in by read_or_build_utent above */
|
||||
setutent();
|
||||
pututline(&utent);
|
||||
endutent();
|
||||
|
||||
Loading…
x
Reference in New Issue
Block a user