glibc/nscd/nscd.c

409 lines
9.7 KiB
C

/* Copyright (c) 1998, 1999, 2000, 2001 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Thorsten Kukuk <kukuk@suse.de>, 1998.
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. */
/* nscd - Name Service Cache Daemon. Caches passwd, group, and hosts. */
#include <argp.h>
#include <assert.h>
#include <errno.h>
#include <error.h>
#include <grp.h>
#include <libintl.h>
#include <locale.h>
#include <pthread.h>
#include <pwd.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include <unistd.h>
#include <sys/socket.h>
#include <sys/un.h>
#include "dbg_log.h"
#include "nscd.h"
/* Get libc version number. */
#include <version.h>
#define PACKAGE _libc_intl_domainname
/* Structure used by main() thread to keep track of the number of
active threads. Used to limit how many threads it will create
and under a shutdown condition to wait till all in-progress
requests have finished before "turning off the lights". */
typedef struct
{
int num_active;
pthread_cond_t thread_exit_cv;
pthread_mutex_t mutex;
} thread_info_t;
thread_info_t thread_info;
int do_shutdown;
int disabled_passwd;
int disabled_group;
int go_background = 1;
const char *server_user;
int secure[lastdb];
int secure_in_use;
static const char *conffile = _PATH_NSCDCONF;
static int check_pid (const char *file);
static int write_pid (const char *file);
static void drop_privileges (void);
/* Name and version of program. */
static void print_version (FILE *stream, struct argp_state *state);
void (*argp_program_version_hook) (FILE *, struct argp_state *) = print_version;
/* Definitions of arguments for argp functions. */
static const struct argp_option options[] =
{
{ "config-file", 'f', N_("NAME"), 0,
N_("Read configuration data from NAME") },
{ "debug", 'd', NULL, 0,
N_("Do not fork and display messages on the current tty") },
{ "nthreads", 't', N_("NUMBER"), 0, N_("Start NUMBER threads") },
{ "shutdown", 'K', NULL, 0, N_("Shut the server down") },
{ "statistic", 'g', NULL, 0, N_("Print current configuration statistic") },
{ "invalidate", 'i', N_("TABLE"), 0,
N_("Invalidate the specified cache") },
{ "secure", 'S', N_("TABLE,yes"), 0, N_("Use separate cache for each user")},
{ NULL, 0, NULL, 0, NULL }
};
/* Short description of program. */
static const char doc[] = N_("Name Service Cache Daemon.");
/* Prototype for option handler. */
static error_t parse_opt (int key, char *arg, struct argp_state *state);
/* Data structure to communicate with argp functions. */
static struct argp argp =
{
options, parse_opt, NULL, doc,
};
int
main (int argc, char **argv)
{
int remaining;
/* Set locale via LC_ALL. */
setlocale (LC_ALL, "");
/* Set the text message domain. */
textdomain (PACKAGE);
/* Parse and process arguments. */
argp_parse (&argp, argc, argv, 0, &remaining, NULL);
if (remaining != argc)
{
error (0, 0, gettext ("wrong number of arguments"));
argp_help (&argp, stdout, ARGP_HELP_SEE, program_invocation_short_name);
exit (EXIT_FAILURE);
}
/* Check if we are already running. */
if (check_pid (_PATH_NSCDPID))
error (EXIT_FAILURE, 0, _("already running"));
/* Behave like a daemon. */
if (go_background)
{
int i;
if (fork ())
exit (0);
for (i = 0; i < getdtablesize (); i++)
close (i);
if (fork ())
exit (0);
setsid ();
chdir ("/");
openlog ("nscd", LOG_CONS | LOG_ODELAY, LOG_DAEMON);
if (write_pid (_PATH_NSCDPID) < 0)
dbg_log ("%s: %s", _PATH_NSCDPID, strerror (errno));
/* Ignore job control signals. */
signal (SIGTTOU, SIG_IGN);
signal (SIGTTIN, SIG_IGN);
signal (SIGTSTP, SIG_IGN);
}
signal (SIGINT, termination_handler);
signal (SIGQUIT, termination_handler);
signal (SIGTERM, termination_handler);
signal (SIGPIPE, SIG_IGN);
/* Cleanup files created by a previous `bind'. */
unlink (_PATH_NSCDSOCKET);
/* Init databases. */
nscd_init (conffile);
/* Change to unprivileged UID if specifed in config file */
if(server_user && !secure_in_use)
drop_privileges ();
/* Handle incoming requests */
start_threads ();
return 0;
}
/* Handle program arguments. */
static error_t
parse_opt (int key, char *arg, struct argp_state *state)
{
switch (key)
{
case 'd':
++debug_level;
go_background = 0;
break;
case 'f':
conffile = arg;
break;
case 'K':
if (getuid () != 0)
error (EXIT_FAILURE, 0, _("Only root is allowed to use this option!"));
{
int sock = nscd_open_socket ();
request_header req;
ssize_t nbytes;
if (sock == -1)
exit (EXIT_FAILURE);
req.version = NSCD_VERSION;
req.type = SHUTDOWN;
req.key_len = 0;
nbytes = TEMP_FAILURE_RETRY (write (sock, &req,
sizeof (request_header)));
close (sock);
exit (nbytes != sizeof (request_header) ? EXIT_FAILURE : EXIT_SUCCESS);
}
case 'g':
if (getuid () != 0)
error (EXIT_FAILURE, 0, _("Only root is allowed to use this option!"));
receive_print_stats ();
/* Does not return. */
case 'i':
if (getuid () != 0)
error (EXIT_FAILURE, 0, _("Only root is allowed to use this option!"));
else
{
int sock = nscd_open_socket ();
request_header req;
ssize_t nbytes;
if (sock == -1)
exit (EXIT_FAILURE);
if (strcmp (arg, "passwd") == 0)
req.key_len = sizeof "passwd";
else if (strcmp (arg, "group") == 0)
req.key_len = sizeof "group";
else if (strcmp (arg, "hosts") == 0)
req.key_len = sizeof "hosts";
else
return ARGP_ERR_UNKNOWN;
req.version = NSCD_VERSION;
req.type = INVALIDATE;
nbytes = TEMP_FAILURE_RETRY (write (sock, &req,
sizeof (request_header)));
if (nbytes != sizeof (request_header))
{
close (sock);
exit (EXIT_FAILURE);
}
nbytes = TEMP_FAILURE_RETRY (write (sock, (void *)arg, req.key_len));
close (sock);
exit (nbytes != req.key_len ? EXIT_FAILURE : EXIT_SUCCESS);
}
case 't':
nthreads = atol (arg);
break;
case 'S':
if (strcmp (arg, "passwd,yes") == 0)
secure_in_use = secure[pwddb] = 1;
else if (strcmp (arg, "group,yes") == 0)
secure_in_use = secure[grpdb] = 1;
else if (strcmp (arg, "hosts,yes") == 0)
secure_in_use = secure[hstdb] = 1;
break;
default:
return ARGP_ERR_UNKNOWN;
}
return 0;
}
/* Print the version information. */
static void
print_version (FILE *stream, struct argp_state *state)
{
fprintf (stream, "nscd (GNU %s) %s\n", PACKAGE, VERSION);
fprintf (stream, 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\
"), "2001");
fprintf (stream, gettext ("Written by %s.\n"),
"Thorsten Kukuk and Ulrich Drepper");
}
/* Create a socket connected to a name. */
int
nscd_open_socket (void)
{
struct sockaddr_un addr;
int sock;
sock = socket (PF_UNIX, SOCK_STREAM, 0);
if (sock < 0)
return -1;
addr.sun_family = AF_UNIX;
assert (sizeof (addr.sun_path) >= sizeof (_PATH_NSCDSOCKET));
strcpy (addr.sun_path, _PATH_NSCDSOCKET);
if (connect (sock, (struct sockaddr *) &addr, sizeof (addr)) < 0)
{
close (sock);
return -1;
}
return sock;
}
/* Cleanup. */
void
termination_handler (int signum)
{
close_sockets ();
/* Clean up the file created by `bind'. */
unlink (_PATH_NSCDSOCKET);
/* Clean up pid file. */
unlink (_PATH_NSCDPID);
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 (file, "r");
if (fp)
{
pid_t pid;
int n;
n = fscanf (fp, "%d", &pid);
fclose (fp);
if (n != 1 || 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 (file, "w");
if (fp == NULL)
return -1;
fprintf (fp, "%d\n", getpid ());
if (fflush (fp) || ferror (fp))
return -1;
fclose (fp);
return 0;
}
/* Look up the uid and gid associated with the user we are supposed to run
the server as, and then call setgid(), setgroups(), and setuid().
Otherwise, abort- we should not run as root if the configuration file
specifically tells us not to. */
static void
drop_privileges (void)
{
int buflen = 256;
char *buffer = alloca (buflen);
struct passwd resultbuf;
struct passwd *pwd;
while (__getpwnam_r (server_user, &resultbuf, buffer, buflen, &pwd) != 0
&& errno == ERANGE)
{
errno = 0;
buflen += 256;
buffer = alloca (buflen);
}
if(!pwd)
{
dbg_log (_("Failed to look up user '%s' to run server as"),
server_user);
exit(1);
}
setgroups (0, NULL);
setgid (pwd->pw_gid);
setuid (pwd->pw_uid);
}