glibc/nscd/nscd.c

/* Copyright (c) 1998 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Thorsten Kukuk <kukuk@vt.uni-paderborn.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 and group.  */

#include <argp.h>
#include <errno.h>
#include <error.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 = 0;
int disabled_passwd = 0;
int disabled_group = 0;
int go_background = 1;
const char *conffile = _PATH_NSCDCONF;

static void termination_handler (int signum);
static int check_pid (const char *file);
static int write_pid (const char *file);
static void handle_requests (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") },
  { "shutdown", 'K', NULL, 0, N_("Shut the server down") },
  { "statistic", 'g', NULL, 0, N_("Print current configuration statistic") },
  { NULL, 0, NULL, 0, NULL }
};

/* Short description of program.  */
static const char doc[] = N_("Name Switch Cache Daemon.");

/* Prototype for option handler.  */
static error_t parse_opt __P ((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))
    {
      fputs (_("already running"), stderr);
      exit (EXIT_FAILURE);
    }

  /* 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);

      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);

  nscd_parse_file (conffile);

  /* Create first sockets */
  init_sockets ();
  /* Init databases */
  if ((cache_pwdinit () < 0) || (cache_grpinit () < 0))
    {
      fputs (_("Not enough memory\n"), stderr);
      return 1;
    }
  /* Handle incoming requests */
  handle_requests ();

  return 0;
}


/* Handle program arguments.  */
static error_t
parse_opt (int key, char *arg, struct argp_state *state)
{
  switch (key)
    {
    case 'd':
      debug_flag = 1;
      go_background = 0;
      break;
    case 'f':
      conffile = arg;
      break;
    case 'K':
      if (getuid () != 0)
	{
	  printf (_("Only root is allowed to use this option!\n\n"));
	  exit (EXIT_FAILURE);
	}
      {
	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 = write (sock, &req, sizeof (request_header));
	close (sock);
	if (nbytes != req.key_len)
	  exit (EXIT_FAILURE);
	else
	  exit (EXIT_SUCCESS);
      }
    case 'g':
      print_stat ();
      exit (EXIT_SUCCESS);
    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\
"), "1998");
  fprintf (stream, gettext ("Written by %s.\n"), "Thorsten Kukuk");
}


/* 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;
  strcpy (addr.sun_path, _PATH_NSCDSOCKET);
  if (connect (sock, (struct sockaddr *) &addr, sizeof (addr)) < 0)
    {
      close (sock);
      return -1;
    }

  return sock;
}

/* Cleanup.  */
static void
termination_handler (int signum)
{
  close_sockets ();

  /* Clean up the files 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;

      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 (file, "w");
  if (fp == NULL)
    return -1;

  fprintf (fp, "%d\n", getpid ());
  if (ferror (fp))
    return -1;

  fclose (fp);

  return 0;
}

/* Type of the lookup function for netname2user.  */
typedef int (*pwbyname_function) (const char *name, struct passwd *pw,
				   char *buffer, size_t buflen);

/* Handle incoming requests.  */
static
void handle_requests (void)
{
  request_header req;
  int conn; /* Handle on which connection (client) the request came from.  */
  int done = 0;
  char *key;
  pthread_attr_t th_attr;

  /* We will create all threads detached.  Therefore prepare an attribute
     now.  */
  pthread_attr_init (&th_attr);
  pthread_attr_setdetachstate (&th_attr, PTHREAD_CREATE_DETACHED);

  while (!done)
    {
      key = NULL;
      get_request (&conn, &req, &key);
      if (debug_flag)
	dbg_log (_("handle_requests: request received (Version = %d)"),
		 req.version);
      switch (req.type)
	{
	case GETPWBYNAME:
	  {
	    param_t *param = malloc (sizeof (param_t));
	    pthread_t thread;
	    int status;

	    if (debug_flag)
	      dbg_log ("\tGETPWBYNAME (%s)", key);
	    param->key = key;
	    param->conn = conn;
	    if (disabled_passwd)
	      status = pthread_create (&thread, &th_attr, cache_pw_disabled,
				       (void *)param);
	    else
	      status = pthread_create (&thread, &th_attr, cache_getpwnam,
				       (void *)param);
	    if (status != 0)
	      {
		dbg_log (_("Creation of thread failed: %s"), strerror (errno));
		close_socket (conn);
	      }
	    pthread_detach (thread);
	  }
	  break;
	case GETPWBYUID:
	  {
	    param_t *param = malloc (sizeof (param_t));
	    pthread_t thread;
	    int status;

	    if (debug_flag)
	      dbg_log ("\tGETPWBYUID (%s)", key);
	    param->key = key;
	    param->conn = conn;
	    if (disabled_passwd)
	      status = pthread_create (&thread, &th_attr, cache_pw_disabled,
			      (void *)param);
	    else
	      status = pthread_create (&thread, &th_attr, cache_getpwuid,
				       (void *)param);
	    if (status != 0)
	      {
		dbg_log (_("Creation of thread failed: %s"), strerror (errno));
		close_socket (conn);
	      }
	  }
	  break;
	case GETGRBYNAME:
	  {
	    param_t *param = malloc (sizeof (param_t));
	    pthread_t thread;
	    int status;

	    if (debug_flag)
	      dbg_log ("\tGETGRBYNAME (%s)", key);
	    param->key = key;
	    param->conn = conn;
	    if (disabled_group)
	      status = pthread_create (&thread, &th_attr, cache_gr_disabled,
				       (void *)param);
	    else
	      status = pthread_create (&thread, &th_attr, cache_getgrnam,
				       (void *)param);
	    if (status != 0)
	      {
		dbg_log (_("Creation of thread failed: %s"), strerror (errno));
		close_socket (conn);
	      }
	  }
	  break;
	case GETGRBYGID:
	  {
	    param_t *param = malloc (sizeof (param_t));
	    pthread_t thread;
	    int status;

	    if (debug_flag)
	      dbg_log ("\tGETGRBYGID (%s)", key);
	    param->key = key;
	    param->conn = conn;
	    if (disabled_group)
	      status = pthread_create (&thread, &th_attr, cache_gr_disabled,
				       (void *)param);
	    else
	      status = pthread_create (&thread, &th_attr, cache_getgrgid,
				       (void *)param);
	    if (status != 0)
	      {
		dbg_log (_("Creation of thread failed: %s"), strerror (errno));
		close_socket (conn);
	      }
	  }
	  break;
	case GETHOSTBYNAME:
	  /* Not yetimplemented.  */
	  close_socket (conn);
	  break;
	case GETHOSTBYADDR:
	  /* Not yet implemented. */
	  close_socket (conn);
	  break;
	case SHUTDOWN:
	  do_shutdown = 1;
	  close_socket (0);
	  close_socket (conn);
	  /* Clean up the files created by `bind'.  */
	  unlink (_PATH_NSCDSOCKET);
	  /* Clean up pid file.  */
	  unlink (_PATH_NSCDPID);
	  done = 1;
	  break;
	case GETSTAT:
	  {
	    stat_response_header resp;

	    if (debug_flag)
	      dbg_log ("\tGETSTAT");

	    get_pw_stat (&resp);
	    get_gr_stat (&resp);
	    resp.debug_level = debug_flag;
	    resp.pw_enabled = !disabled_passwd;
	    resp.gr_enabled = !disabled_group;

	    stat_send (conn, &resp);

	    close_socket (conn);
	  }
	  break;
	default:
	  dbg_log (_("Unknown request (%d)"), req.type);
	  break;
	}
    }

  pthread_attr_destroy (&th_attr);
}