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Diffstat (limited to 'login/utmpd/utmpd.c')
-rw-r--r--login/utmpd/utmpd.c384
1 files changed, 384 insertions, 0 deletions
diff --git a/login/utmpd/utmpd.c b/login/utmpd/utmpd.c
new file mode 100644
index 0000000000..e11218151c
--- /dev/null
+++ b/login/utmpd/utmpd.c
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+/* Copyright (C) 1997 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+ Contributed by Mark Kettenis <kettenis@phys.uva.nl>, 1997.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Library General Public License as
+ published by the Free Software Foundation; either version 2 of the
+ License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Library General Public License for more details.
+
+ You should have received a copy of the GNU Library General Public
+ License along with the GNU C Library; see the file COPYING.LIB. If not,
+ write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ Boston, MA 02111-1307, USA. */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <getopt.h>
+#include <libintl.h>
+#include <pwd.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <signal.h>
+#include <string.h>
+#include <sys/select.h>
+#include <sys/socket.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/un.h>
+#include <syslog.h>
+#include <unistd.h>
+
+#include "utmpd.h"
+#include "utmpd-private.h"
+
+/* Get libc version number. */
+#include "../../version.h"
+
+#define PACKAGE "libc"
+
+/* Long options. */
+static const struct option long_options[] =
+{
+ { "debug", no_argument, NULL, 'd' },
+ { "help", no_argument, NULL, 'h' },
+ { "version", no_argument, NULL, 'V' },
+ { NULL, 0, NULL, 0}
+};
+
+/* The UTMP database. */
+utmp_database *utmp_db;
+
+/* The socket for read only requests. */
+int ro_sock = -1;
+
+/* The socket for read/write requests. */
+int rw_sock = -1;
+
+
+/* Prototypes for the local functions. */
+static void usage (int status) __attribute__ ((noreturn));
+static void drop_priviliges (void);
+static int make_socket (const char *name);
+static void handle_requests (void) __attribute__ ((noreturn));
+static void termination_handler (int signum);
+static int check_pid (const char *file);
+static int write_pid (const char *file);
+
+
+int
+main (int argc, char *argv[])
+{
+ mode_t mask;
+ int debug;
+ int do_help;
+ int do_version;
+ int opt;
+
+ /* Initialize local variables. */
+ debug = 0;
+ do_help = 0;
+ do_version = 0;
+
+ while ((opt = getopt_long (argc, argv, "dhV", long_options, NULL)) != -1)
+ switch (opt)
+ {
+ case '\0': /* Long option. */
+ break;
+ case 'h':
+ do_help = 1;
+ break;
+ case 'd':
+ debug = 1;
+ break;
+ case 'V':
+ do_version = 1;
+ break;
+ default:
+ usage (EXIT_FAILURE);
+ }
+
+ /* Version information is reequested. */
+ if (do_version)
+ {
+ printf ("utmpd (GNU %s) %s\n", PACKAGE, VERSION);
+ printf (gettext ("\
+Copyright (C) %s Free Software Foundation, Inc.\n\
+This is free software; see the source for copying conditions. There is NO\n\
+warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n\
+"), "1997");
+ printf (gettext ("Written by %s.\n"), "Mark Kettenis");
+
+ exit (EXIT_SUCCESS);
+ }
+
+ /* Help is requested. */
+ if (do_help)
+ usage (EXIT_SUCCESS);
+
+ signal (SIGINT, termination_handler);
+ signal (SIGTERM, termination_handler);
+
+ /* Check if we are already running. */
+ if (check_pid (_PATH_UTMPDPID))
+ error (EXIT_FAILURE, 0, "already running");
+
+ /* Open UTMP database. */
+ utmp_db = open_database (_PATH_UTMP "x", _PATH_UTMP);
+ if (utmp_db == NULL)
+ error (EXIT_FAILURE, errno, "%s", _PATH_UTMP);
+
+ /* Create sockets, with the right permissions. */
+ mask = umask (S_IXUSR | S_IXGRP | S_IXOTH);
+ ro_sock = make_socket (_PATH_UTMPD_RO);
+ umask (S_IXUSR | S_IRWXG | S_IRWXO);
+ rw_sock = make_socket (_PATH_UTMPD_RW);
+ umask (mask);
+
+ /* Set the sockets up to accept connections. */
+ if (listen (ro_sock, MAX_CONNECTIONS) < 0
+ || listen (rw_sock, MAX_CONNECTIONS) < 0)
+ error (EXIT_FAILURE, errno, "cannot enable socket to accept connections");
+
+ /* Behave like a daemon. */
+ if (!debug)
+ {
+ openlog ("utmpd", LOG_CONS | LOG_ODELAY, LOG_DAEMON);
+
+ if (daemon (0, 0) < 0)
+ error (EXIT_FAILURE, errno, "cannot auto-background");
+ forked = 1;
+
+ if (write_pid (_PATH_UTMPDPID) < 0)
+ warning (errno, "%s", _PATH_UTMPDPID);
+ }
+
+ /* Drop priviliges. */
+ drop_priviliges ();
+
+ /* Handle incoming requests. */
+ handle_requests ();
+}
+
+
+/* Display usage information and exit. */
+static void
+usage (int status)
+{
+ if (status != EXIT_SUCCESS)
+ fprintf (stderr, gettext ("Try `%s --help' for more information.\n"),
+ program_invocation_name);
+ else
+ {
+ printf (gettext ("\
+Usage: %s [OPTION]...\n\
+ -d, --debug do not fork and display messages on the current tty\n\
+ -h, --help display this help and exit\n\
+ -V, --version output version information and exit\n"),
+ program_invocation_name);
+ fputs (gettext ("\
+Report bugs to <kettenis@phys.uva.nl>.\n"),
+ stdout);
+ }
+
+ exit (status);
+}
+
+
+/* Drop priviliges. */
+static void
+drop_priviliges (void)
+{
+ struct passwd *pw;
+
+ pw = getpwnam ("daemon");
+ if (pw)
+ {
+ seteuid (pw->pw_uid);
+ setegid (pw->pw_gid);
+ }
+}
+
+
+/* Make a socket in the file namespace using the filename NAME as the
+ socket's address. */
+static int
+make_socket (const char *name)
+{
+ struct sockaddr_un addr;
+ size_t size;
+ int sock;
+
+ /* Create the socket. */
+ sock = socket (PF_UNIX, SOCK_STREAM, 0);
+ if (sock < 0)
+ error (EXIT_FAILURE, errno, "cannot create socket");
+
+ /* Bind a name to the socket. */
+ addr.sun_family = AF_UNIX;
+ strcpy (addr.sun_path, name);
+
+ /* The size of the address is the offset of the start
+ of the filename, plus its length, plus one for the
+ terminating null byte. */
+ size = (offsetof (struct sockaddr_un, sun_path)
+ + strlen (addr.sun_path));
+
+ if (bind (sock, (struct sockaddr *) &addr, size) < 0)
+ error (EXIT_FAILURE, errno, "%s", name);
+
+ return sock;
+}
+
+
+/* Hanlde incoming requests. */
+static
+void handle_requests (void)
+{
+ client_connection *connection;
+ fd_set active_read_fd_set;
+ fd_set active_write_fd_set;
+ fd_set read_fd_set;
+ fd_set write_fd_set;
+ int fd;
+
+ /* Initialize the set of active sockets. */
+ FD_ZERO (&active_read_fd_set);
+ FD_ZERO (&active_write_fd_set);
+ FD_SET (rw_sock, &active_read_fd_set);
+ FD_SET (ro_sock, &active_read_fd_set);
+
+ while (1)
+ {
+ /* Block until input arrives on one or more active sockets. */
+ read_fd_set = active_read_fd_set;
+ write_fd_set = active_write_fd_set;
+ if (select (FD_SETSIZE, &read_fd_set, &write_fd_set, NULL, NULL) < 0)
+ error (EXIT_FAILURE, errno, "cannot get input on sockets");
+
+ /* Service all the sockets with input pending. */
+ for (fd = 0; fd < FD_SETSIZE; fd++)
+ {
+ if (FD_ISSET (fd, &read_fd_set))
+ {
+ if (fd == ro_sock || fd == rw_sock)
+ {
+ int access = ((fd == rw_sock) ? (R_OK | W_OK) : R_OK);
+
+ connection = accept_connection (fd, access);
+ if (connection == NULL)
+ error (0, errno, "cannot accept connection");
+
+ FD_SET (connection->sock, &active_read_fd_set);
+ }
+ else
+ {
+ connection = find_connection (fd);
+ if (connection == NULL)
+ error (EXIT_FAILURE, 0, "cannot find connection");
+
+ if (read_data (connection) < 0)
+ {
+ close_connection (connection);
+ FD_CLR (fd, &active_read_fd_set);
+ FD_CLR (fd, &active_write_fd_set);
+ }
+
+ if (connection->write_ptr > connection->write_base)
+ FD_SET (fd, &active_write_fd_set);
+ }
+ }
+ if (FD_ISSET (fd, &write_fd_set) &&
+ fd != rw_sock && fd != ro_sock)
+ {
+ connection = find_connection (fd);
+ if (connection == NULL)
+ error (EXIT_FAILURE, 0, "cannot find connection");
+
+ if (write_data (connection) < 0)
+ {
+ close_connection (connection);
+ FD_CLR (fd, &active_read_fd_set);
+ FD_CLR (fd, &active_write_fd_set);
+ }
+
+ if (connection->write_ptr == connection->write_base)
+ FD_CLR (fd, &active_write_fd_set);
+ }
+ }
+ }
+}
+
+
+/* Cleanup. */
+static void
+termination_handler (int signum)
+{
+ /* Close sockets. */
+ close (ro_sock);
+ close (rw_sock);
+
+ /* Restore user id. */
+ seteuid (getuid ());
+
+ /* Clean up the files created by `bind'. */
+ unlink (_PATH_UTMPD_RO);
+ unlink (_PATH_UTMPD_RW);
+
+ if (utmp_db)
+ close_database (utmp_db);
+
+ /* Clean up pid file. */
+ unlink (_PATH_UTMPDPID);
+
+ exit (EXIT_SUCCESS);
+}
+
+
+/* Returns 1 if the process in pid file FILE is running, 0 if not. */
+static int
+check_pid (const char *file)
+{
+ FILE *fp;
+
+ fp = fopen (_PATH_UTMPDPID, "r");
+ if (fp)
+ {
+ pid_t pid;
+
+ fscanf (fp, "%d", &pid);
+ fclose (fp);
+
+ if (kill (pid, 0) == 0)
+ return 1;
+ }
+
+ return 0;
+}
+
+/* Write the current process id to the file FILE. Returns 0 if
+ successful, -1 if not. */
+static int
+write_pid (const char *file)
+{
+ FILE *fp;
+
+ fp = fopen (_PATH_UTMPDPID, "w");
+ if (fp == NULL)
+ return -1;
+
+ fprintf (fp, "%d\n", getpid ());
+ if (ferror (fp))
+ return -1;
+
+ fclose (fp);
+
+ return 0;
+}
+
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