nscd/nscd.c

   1 /* Copyright (c) 1998 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Thorsten Kukuk <kukuk@vt.uni-paderborn.de>, 1998.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Library General Public License as
   7    published by the Free Software Foundation; either version 2 of the
   8    License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Library General Public License for more details.
  14
  15    You should have received a copy of the GNU Library General Public
  16    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  17    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  18    Boston, MA 02111-1307, USA. */
  19
  20 /* nscd - Name Service Cache Daemon. Caches passwd, group, and hosts.  */
  21
  22 #include <argp.h>
  23 #include <assert.h>
  24 #include <errno.h>
  25 #include <error.h>
  26 #include <libintl.h>
  27 #include <locale.h>
  28 #include <pthread.h>
  29 #include <pwd.h>
  30 #include <signal.h>
  31 #include <stdio.h>
  32 #include <stdlib.h>
  33 #include <string.h>
  34 #include <syslog.h>
  35 #include <unistd.h>
  36 #include <sys/socket.h>
  37 #include <sys/un.h>
  38
  39 #include "dbg_log.h"
  40 #include "nscd.h"
  41
  42 /* Get libc version number.  */
  43 #include <version.h>
  44
  45 #define PACKAGE _libc_intl_domainname
  46
  47 /* Structure used by main() thread to keep track of the number of
  48    active threads.  Used to limit how many threads it will create
  49    and under a shutdown condition to wait till all in-progress
  50    requests have finished before "turning off the lights".  */
  51
  52 typedef struct
  53 {
  54   int             num_active;
  55   pthread_cond_t  thread_exit_cv;
  56   pthread_mutex_t mutex;
  57 } thread_info_t;
  58
  59 thread_info_t thread_info;
  60
  61 int do_shutdown = 0;
  62 int disabled_passwd = 0;
  63 int disabled_group = 0;
  64 int go_background = 1;
  65 static const char *conffile = _PATH_NSCDCONF;
  66
  67 static int check_pid (const char *file);
  68 static int write_pid (const char *file);
  69
  70 /* Name and version of program.  */
  71 static void print_version (FILE *stream, struct argp_state *state);
  72 void (*argp_program_version_hook) (FILE *, struct argp_state *) = print_version;
  73
  74 /* Definitions of arguments for argp functions.  */
  75 static const struct argp_option options[] =
  76 {
  77   { "config-file", 'f', N_("NAME"), 0,
  78     N_("Read configuration data from NAME") },
  79   { "debug", 'd', NULL, 0,
  80     N_("Do not fork and display messages on the current tty") },
  81   { "nthreads", 't', N_("NUMBER"), 0, N_("Start NUMBER threads") },
  82   { "shutdown", 'K', NULL, 0, N_("Shut the server down") },
  83   { "statistic", 'g', NULL, 0, N_("Print current configuration statistic") },
  84   { NULL, 0, NULL, 0, NULL }
  85 };
  86
  87 /* Short description of program.  */
  88 static const char doc[] = N_("Name Service Cache Daemon.");
  89
  90 /* Prototype for option handler.  */
  91 static error_t parse_opt __P ((int key, char *arg, struct argp_state *state));
  92
  93 /* Data structure to communicate with argp functions.  */
  94 static struct argp argp =
  95 {
  96   options, parse_opt, NULL, doc,
  97 };
  98
  99 int
 100 main (int argc, char **argv)
 101 {
 102   int remaining;
 103
 104   /* Set locale via LC_ALL.  */
 105   setlocale (LC_ALL, "");
 106   /* Set the text message domain.  */
 107   textdomain (PACKAGE);
 108
 109   /* Parse and process arguments.  */
 110   argp_parse (&argp, argc, argv, 0, &remaining, NULL);
 111
 112   if (remaining != argc)
 113     {
 114       error (0, 0, gettext ("wrong number of arguments"));
 115       argp_help (&argp, stdout, ARGP_HELP_SEE, program_invocation_short_name);
 116       exit (EXIT_FAILURE);
 117     }
 118
 119   /* Check if we are already running. */
 120   if (check_pid (_PATH_NSCDPID))
 121     error (EXIT_FAILURE, 0, _("already running"));
 122
 123   /* Behave like a daemon.  */
 124   if (go_background)
 125     {
 126       int i;
 127
 128       if (fork ())
 129         exit (0);
 130
 131       for (i = 0; i < getdtablesize (); i++)
 132         close (i);
 133
 134       if (fork ())
 135         exit (0);
 136
 137       chdir ("/");
 138
 139       openlog ("nscd", LOG_CONS | LOG_ODELAY, LOG_DAEMON);
 140
 141       if (write_pid (_PATH_NSCDPID) < 0)
 142         dbg_log ("%s: %s", _PATH_NSCDPID, strerror (errno));
 143
 144       /* Ignore job control signals.  */
 145       signal (SIGTTOU, SIG_IGN);
 146       signal (SIGTTIN, SIG_IGN);
 147       signal (SIGTSTP, SIG_IGN);
 148     }
 149
 150   signal (SIGINT, termination_handler);
 151   signal (SIGQUIT, termination_handler);
 152   signal (SIGTERM, termination_handler);
 153   signal (SIGPIPE, SIG_IGN);
 154
 155   /* Cleanup files created by a previous `bind'.  */
 156   unlink (_PATH_NSCDSOCKET);
 157
 158   /* Init databases.  */
 159   nscd_init (conffile);
 160
 161   /* Handle incoming requests */
 162   start_threads ();
 163
 164   return 0;
 165 }
 166
 167
 168 /* Handle program arguments.  */
 169 static error_t
 170 parse_opt (int key, char *arg, struct argp_state *state)
 171 {
 172   switch (key)
 173     {
 174     case 'd':
 175       ++debug_level;
 176       go_background = 0;
 177       break;
 178
 179     case 'f':
 180       conffile = arg;
 181       break;
 182
 183     case 'K':
 184       if (getuid () != 0)
 185         error (EXIT_FAILURE, 0, _("Only root is allowed to use this option!"));
 186       {
 187         int sock = nscd_open_socket ();
 188         request_header req;
 189         ssize_t nbytes;
 190
 191         if (sock == -1)
 192           exit (EXIT_FAILURE);
 193
 194         req.version = NSCD_VERSION;
 195         req.type = SHUTDOWN;
 196         req.key_len = 0;
 197         nbytes = TEMP_FAILURE_RETRY (write (sock, &req,
 198                                             sizeof (request_header)));
 199         close (sock);
 200         exit (nbytes != sizeof (request_header) ? EXIT_FAILURE : EXIT_SUCCESS);
 201       }
 202
 203     case 'g':
 204       receive_print_stats ();
 205       /* Does not return.  */
 206
 207     case 't':
 208       nthreads = atol (arg);
 209       break;
 210
 211     default:
 212       return ARGP_ERR_UNKNOWN;
 213     }
 214
 215   return 0;
 216 }
 217
 218 /* Print the version information.  */
 219 static void
 220 print_version (FILE *stream, struct argp_state *state)
 221 {
 222   fprintf (stream, "nscd (GNU %s) %s\n", PACKAGE, VERSION);
 223   fprintf (stream, gettext ("\
 224 Copyright (C) %s Free Software Foundation, Inc.\n\
 225 This is free software; see the source for copying conditions.  There is NO\n\
 226 warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n\
 227 "), "1998");
 228   fprintf (stream, gettext ("Written by %s.\n"),
 229            "Thorsten Kukuk and Ulrich Drepper");
 230 }
 231
 232
 233 /* Create a socket connected to a name.  */
 234 int
 235 nscd_open_socket (void)
 236 {
 237   struct sockaddr_un addr;
 238   int sock;
 239
 240   sock = socket (PF_UNIX, SOCK_STREAM, 0);
 241   if (sock < 0)
 242     return -1;
 243
 244   addr.sun_family = AF_UNIX;
 245   assert (sizeof (addr.sun_path) >= sizeof (_PATH_NSCDSOCKET));
 246   strcpy (addr.sun_path, _PATH_NSCDSOCKET);
 247   if (connect (sock, (struct sockaddr *) &addr, sizeof (addr)) < 0)
 248     {
 249       close (sock);
 250       return -1;
 251     }
 252
 253   return sock;
 254 }
 255
 256 /* Cleanup.  */
 257 void
 258 termination_handler (int signum)
 259 {
 260   close_sockets ();
 261
 262   /* Clean up the file created by `bind'.  */
 263   unlink (_PATH_NSCDSOCKET);
 264
 265   /* Clean up pid file.  */
 266   unlink (_PATH_NSCDPID);
 267
 268   exit (EXIT_SUCCESS);
 269 }
 270
 271 /* Returns 1 if the process in pid file FILE is running, 0 if not.  */
 272 static int
 273 check_pid (const char *file)
 274 {
 275   FILE *fp;
 276
 277   fp = fopen (file, "r");
 278   if (fp)
 279     {
 280       pid_t pid;
 281       int n;
 282
 283       n = fscanf (fp, "%d", &pid);
 284       fclose (fp);
 285
 286       if (n != 1 || kill (pid, 0) == 0)
 287         return 1;
 288     }
 289
 290   return 0;
 291 }
 292
 293 /* Write the current process id to the file FILE.
 294    Returns 0 if successful, -1 if not.  */
 295 static int
 296 write_pid (const char *file)
 297 {
 298   FILE *fp;
 299
 300   fp = fopen (file, "w");
 301   if (fp == NULL)
 302     return -1;
 303
 304   fprintf (fp, "%d\n", getpid ());
 305   if (fflush (fp) || ferror (fp))
 306     return -1;
 307
 308   fclose (fp);
 309
 310   return 0;
 311 }