diff options
Diffstat (limited to 'src/logoutd.c')
| -rw-r--r-- | src/logoutd.c | 279 |
1 files changed, 279 insertions, 0 deletions
diff --git a/src/logoutd.c b/src/logoutd.c new file mode 100644 index 0000000..03680f3 --- /dev/null +++ b/src/logoutd.c @@ -0,0 +1,279 @@ +/* + * SPDX-FileCopyrightText: 1991 - 1993, Julianne Frances Haugh + * SPDX-FileCopyrightText: 1996 - 2000, Marek Michałkiewicz + * SPDX-FileCopyrightText: 2001 - 2006, Tomasz Kłoczko + * + * SPDX-License-Identifier: BSD-3-Clause + */ + +#include <config.h> + +#ident "$Id$" + +#include <fcntl.h> +#include <signal.h> +#include <stdio.h> +#include <sys/stat.h> +#include <sys/types.h> +#include "defines.h" +#include "prototypes.h" +#include "shadowlog.h" +/* + * Global variables + */ +const char *Prog; + +#ifndef DEFAULT_HUP_MESG +#define DEFAULT_HUP_MESG _("login time exceeded\n\n") +#endif + +#ifndef HUP_MESG_FILE +#define HUP_MESG_FILE "/etc/logoutd.mesg" +#endif + +/* local function prototypes */ +#ifdef USE_UTMPX +static int check_login (const struct utmpx *ut); +#else /* !USE_UTMPX */ +static int check_login (const struct utmp *ut); +#endif /* !USE_UTMPX */ +static void send_mesg_to_tty (int tty_fd); + +/* + * check_login - check if user (struct utmpx/utmp) allowed to stay logged in + */ +#ifdef USE_UTMPX +static int check_login (const struct utmpx *ut) +#else /* !USE_UTMPX */ +static int check_login (const struct utmp *ut) +#endif /* !USE_UTMPX */ +{ + char user[sizeof (ut->ut_user) + 1]; + time_t now; + + /* + * ut_user may not have the terminating NUL. + */ + strncpy (user, ut->ut_user, sizeof (ut->ut_user)); + user[sizeof (ut->ut_user)] = '\0'; + + (void) time (&now); + + /* + * Check if they are allowed to be logged in right now. + */ + if (!isttytime (user, ut->ut_line, now)) { + return 0; + } + return 1; +} + + +static void send_mesg_to_tty (int tty_fd) +{ + TERMIO oldt, newt; + FILE *mesg_file, *tty_file; + bool is_tty; + + tty_file = fdopen (tty_fd, "w"); + if (NULL == tty_file) { + return; + } + + is_tty = (GTTY (tty_fd, &oldt) == 0); + if (is_tty) { + /* Suggested by Ivan Nejgebauar <ian@unsux.ns.ac.yu>: + set OPOST before writing the message. */ + newt = oldt; + newt.c_oflag |= OPOST; + STTY (tty_fd, &newt); + } + + mesg_file = fopen (HUP_MESG_FILE, "r"); + if (NULL != mesg_file) { + int c; + while ((c = getc (mesg_file)) != EOF) { + if (c == '\n') { + putc ('\r', tty_file); + } + putc (c, tty_file); + } + fclose (mesg_file); + } else { + fputs (DEFAULT_HUP_MESG, tty_file); + } + fflush (tty_file); + fclose (tty_file); + + if (is_tty) { + STTY (tty_fd, &oldt); + } +} + + +/* + * logoutd - logout daemon to enforce /etc/porttime file policy + * + * logoutd is started at system boot time and enforces the login + * time and port restrictions specified in /etc/porttime. The + * utmpx/utmp file is periodically scanned and offending users are logged + * off from the system. + */ +int main (int argc, char **argv) +{ + int i; + int status; + pid_t pid; + +#ifdef USE_UTMPX + struct utmpx *ut; +#else /* !USE_UTMPX */ + struct utmp *ut; +#endif /* !USE_UTMPX */ + char user[sizeof (ut->ut_user) + 1]; /* terminating NUL */ + char tty_name[sizeof (ut->ut_line) + 6]; /* /dev/ + NUL */ + int tty_fd; + + if (1 != argc) { + (void) fputs (_("Usage: logoutd\n"), stderr); + } + + (void) setlocale (LC_ALL, ""); + (void) bindtextdomain (PACKAGE, LOCALEDIR); + (void) textdomain (PACKAGE); + +#ifndef DEBUG + for (i = 0; close (i) == 0; i++); + + setpgrp (); + + /* + * Put this process in the background. + */ + pid = fork (); + if (pid > 0) { + /* parent */ + exit (EXIT_SUCCESS); + } else if (pid < 0) { + /* error */ + perror ("fork"); + exit (EXIT_FAILURE); + } +#endif /* !DEBUG */ + + /* + * Start syslogging everything + */ + Prog = Basename (argv[0]); + log_set_progname(Prog); + log_set_logfd(stderr); + + OPENLOG ("logoutd"); + + /* + * Scan the utmpx/utmp file once per minute looking for users that + * are not supposed to still be logged in. + */ + while (true) { + + /* + * Attempt to re-open the utmpx/utmp file. The file is only + * open while it is being used. + */ +#ifdef USE_UTMPX + setutxent (); +#else /* !USE_UTMPX */ + setutent (); +#endif /* !USE_UTMPX */ + + /* + * Read all of the entries in the utmpx/utmp file. The entries + * for login sessions will be checked to see if the user + * is permitted to be signed on at this time. + */ +#ifdef USE_UTMPX + while ((ut = getutxent ()) != NULL) +#else /* !USE_UTMPX */ + while ((ut = getutent ()) != NULL) +#endif /* !USE_UTMPX */ + { + if (ut->ut_type != USER_PROCESS) { + continue; + } + if (ut->ut_user[0] == '\0') { + continue; + } + if (check_login (ut)) { + continue; + } + + /* + * Put the rest of this in a child process. This + * keeps the scan from waiting on other ports to die. + */ + + pid = fork (); + if (pid > 0) { + /* parent */ + continue; + } else if (pid < 0) { + /* failed - give up until the next scan */ + break; + } + /* child */ + + if (strncmp (ut->ut_line, "/dev/", 5) != 0) { + strcpy (tty_name, "/dev/"); + } else { + tty_name[0] = '\0'; + } + + strncat (tty_name, ut->ut_line, UT_LINESIZE); +#ifndef O_NOCTTY +#define O_NOCTTY 0 +#endif + tty_fd = + open (tty_name, O_WRONLY | O_NDELAY | O_NOCTTY); + if (tty_fd != -1) { + send_mesg_to_tty (tty_fd); + close (tty_fd); + sleep (10); + } + + if (ut->ut_pid > 1) { + kill (-ut->ut_pid, SIGHUP); + sleep (10); + kill (-ut->ut_pid, SIGKILL); + } + + strncpy (user, ut->ut_user, sizeof (user) - 1); + user[sizeof (user) - 1] = '\0'; + + SYSLOG ((LOG_NOTICE, + "logged off user '%s' on '%s'", user, + tty_name)); + + /* + * This child has done all it can, drop dead. + */ + exit (EXIT_SUCCESS); + } + +#ifdef USE_UTMPX + endutxent (); +#else /* !USE_UTMPX */ + endutent (); +#endif /* !USE_UTMPX */ + +#ifndef DEBUG + sleep (60); +#endif + /* + * Reap any dead babies ... + */ + while (wait (&status) != -1); + } + + return EXIT_FAILURE; +} + |