nscd/nscd.c

   1 /* Copyright (c) 1998,1999,2000,2001,2002,2003 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Thorsten Kukuk <kukuk@suse.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 Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the 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    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    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 <dirent.h>
  25 #include <errno.h>
  26 #include <error.h>
  27 #include <fcntl.h>
  28 #include <libintl.h>
  29 #include <locale.h>
  30 #include <paths.h>
  31 #include <pthread.h>
  32 #include <signal.h>
  33 #include <stdbool.h>
  34 #include <stdio.h>
  35 #include <stdlib.h>
  36 #include <string.h>
  37 #include <syslog.h>
  38 #include <unistd.h>
  39 #include <sys/socket.h>
  40 #include <sys/stat.h>
  41 #include <sys/un.h>
  42
  43 #include "dbg_log.h"
  44 #include "nscd.h"
  45 #include "../nss/nsswitch.h"
  46 #include <device-nrs.h>
  47
  48 /* Get libc version number.  */
  49 #include <version.h>
  50
  51 #define PACKAGE _libc_intl_domainname
  52
  53 /* Structure used by main() thread to keep track of the number of
  54    active threads.  Used to limit how many threads it will create
  55    and under a shutdown condition to wait till all in-progress
  56    requests have finished before "turning off the lights".  */
  57
  58 typedef struct
  59 {
  60   int             num_active;
  61   pthread_cond_t  thread_exit_cv;
  62   pthread_mutex_t mutex;
  63 } thread_info_t;
  64
  65 thread_info_t thread_info;
  66
  67 int do_shutdown;
  68 int disabled_passwd;
  69 int disabled_group;
  70 int go_background = 1;
  71
  72 int secure[lastdb];
  73 int secure_in_use;
  74 static const char *conffile = _PATH_NSCDCONF;
  75
  76 time_t start_time;
  77
  78 static int check_pid (const char *file);
  79 static int write_pid (const char *file);
  80
  81 /* Name and version of program.  */
  82 static void print_version (FILE *stream, struct argp_state *state);
  83 void (*argp_program_version_hook) (FILE *, struct argp_state *) = print_version;
  84
  85 /* Definitions of arguments for argp functions.  */
  86 static const struct argp_option options[] =
  87 {
  88   { "config-file", 'f', N_("NAME"), 0,
  89     N_("Read configuration data from NAME") },
  90   { "debug", 'd', NULL, 0,
  91     N_("Do not fork and display messages on the current tty") },
  92   { "nthreads", 't', N_("NUMBER"), 0, N_("Start NUMBER threads") },
  93   { "shutdown", 'K', NULL, 0, N_("Shut the server down") },
  94   { "statistic", 'g', NULL, 0, N_("Print current configuration statistic") },
  95   { "invalidate", 'i', N_("TABLE"), 0,
  96     N_("Invalidate the specified cache") },
  97   { "secure", 'S', N_("TABLE,yes"), 0, N_("Use separate cache for each user")},
  98   { NULL, 0, NULL, 0, NULL }
  99 };
 100
 101 /* Short description of program.  */
 102 static const char doc[] = N_("Name Service Cache Daemon.");
 103
 104 /* Prototype for option handler.  */
 105 static error_t parse_opt (int key, char *arg, struct argp_state *state);
 106
 107 /* Data structure to communicate with argp functions.  */
 108 static struct argp argp =
 109 {
 110   options, parse_opt, NULL, doc,
 111 };
 112
 113 /* True if only statistics are requested.  */
 114 static bool get_stats;
 115
 116 int
 117 main (int argc, char **argv)
 118 {
 119   int remaining;
 120
 121   /* Set locale via LC_ALL.  */
 122   setlocale (LC_ALL, "");
 123   /* Set the text message domain.  */
 124   textdomain (PACKAGE);
 125
 126   /* Parse and process arguments.  */
 127   argp_parse (&argp, argc, argv, 0, &remaining, NULL);
 128
 129   if (remaining != argc)
 130     {
 131       error (0, 0, gettext ("wrong number of arguments"));
 132       argp_help (&argp, stdout, ARGP_HELP_SEE, program_invocation_short_name);
 133       exit (EXIT_FAILURE);
 134     }
 135
 136   /* Read the configuration file.  */
 137   if (nscd_parse_file (conffile, dbs) != 0)
 138     {
 139       /* We couldn't read the configuration file.  We don't start the
 140          server.  */
 141       dbg_log (_("cannot read configuration file; this is fatal"));
 142       exit (1);
 143     }
 144
 145   /* Do we only get statistics?  */
 146   if (get_stats)
 147     /* Does not return.  */
 148     receive_print_stats ();
 149
 150   /* Check if we are already running. */
 151   if (check_pid (_PATH_NSCDPID))
 152     error (EXIT_FAILURE, 0, _("already running"));
 153
 154   /* Remember when we started.  */
 155   start_time = time (NULL);
 156
 157   /* Behave like a daemon.  */
 158   if (go_background)
 159     {
 160       int i;
 161
 162       if (fork ())
 163         exit (0);
 164
 165       int nullfd = open (_PATH_DEVNULL, O_RDWR);
 166       if (nullfd != -1)
 167         {
 168           struct stat64 st;
 169
 170           if (fstat64 (nullfd, &st) == 0 && S_ISCHR (st.st_mode) != 0
 171 #if defined DEV_NULL_MAJOR && defined DEV_NULL_MINOR
 172               && st.st_rdev == makedev (DEV_NULL_MAJOR, DEV_NULL_MINOR)
 173 #endif
 174               )
 175             {
 176               /* It is the /dev/null special device alright.  */
 177               (void) dup2 (nullfd, STDIN_FILENO);
 178               (void) dup2 (nullfd, STDOUT_FILENO);
 179               (void) dup2 (nullfd, STDERR_FILENO);
 180
 181               if (nullfd > 2)
 182                 close (nullfd);
 183             }
 184           else
 185             {
 186               /* Ugh, somebody is trying to play a trick on us.  */
 187               close (nullfd);
 188               nullfd = -1;
 189             }
 190         }
 191       int min_close_fd = nullfd == -1 ? 0 : STDERR_FILENO + 1;
 192
 193       DIR *d = opendir ("/proc/self/fd");
 194       if (d != NULL)
 195         {
 196           struct dirent64 *dirent;
 197           int dfdn = dirfd (d);
 198
 199           while ((dirent = readdir64 (d)) != NULL)
 200             {
 201               char *endp;
 202               long int fdn = strtol (dirent->d_name, &endp, 10);
 203
 204               if (*endp == '\0' && fdn != dfdn && fdn >= min_close_fd)
 205                 close ((int) fdn);
 206             }
 207
 208           closedir (d);
 209         }
 210       else
 211         for (i = min_close_fd; i < getdtablesize (); i++)
 212           close (i);
 213
 214       if (fork ())
 215         exit (0);
 216
 217       setsid ();
 218
 219       chdir ("/");
 220
 221       openlog ("nscd", LOG_CONS | LOG_ODELAY, LOG_DAEMON);
 222
 223       if (write_pid (_PATH_NSCDPID) < 0)
 224         dbg_log ("%s: %s", _PATH_NSCDPID, strerror (errno));
 225
 226       /* Ignore job control signals.  */
 227       signal (SIGTTOU, SIG_IGN);
 228       signal (SIGTTIN, SIG_IGN);
 229       signal (SIGTSTP, SIG_IGN);
 230     }
 231
 232   signal (SIGINT, termination_handler);
 233   signal (SIGQUIT, termination_handler);
 234   signal (SIGTERM, termination_handler);
 235   signal (SIGPIPE, SIG_IGN);
 236
 237   /* Cleanup files created by a previous `bind'.  */
 238   unlink (_PATH_NSCDSOCKET);
 239
 240   /* Make sure we do not get recursive calls.  */
 241   __nss_disable_nscd ();
 242
 243   /* Init databases.  */
 244   nscd_init ();
 245
 246   /* Handle incoming requests */
 247   start_threads ();
 248
 249   return 0;
 250 }
 251
 252
 253 /* Handle program arguments.  */
 254 static error_t
 255 parse_opt (int key, char *arg, struct argp_state *state)
 256 {
 257   switch (key)
 258     {
 259     case 'd':
 260       ++debug_level;
 261       go_background = 0;
 262       break;
 263
 264     case 'f':
 265       conffile = arg;
 266       break;
 267
 268     case 'K':
 269       if (getuid () != 0)
 270         error (EXIT_FAILURE, 0, _("Only root is allowed to use this option!"));
 271       {
 272         int sock = nscd_open_socket ();
 273         request_header req;
 274         ssize_t nbytes;
 275
 276         if (sock == -1)
 277           exit (EXIT_FAILURE);
 278
 279         req.version = NSCD_VERSION;
 280         req.type = SHUTDOWN;
 281         req.key_len = 0;
 282         nbytes = TEMP_FAILURE_RETRY (write (sock, &req,
 283                                             sizeof (request_header)));
 284         close (sock);
 285         exit (nbytes != sizeof (request_header) ? EXIT_FAILURE : EXIT_SUCCESS);
 286       }
 287
 288     case 'g':
 289       get_stats = true;
 290       break;
 291
 292     case 'i':
 293       if (getuid () != 0)
 294         error (EXIT_FAILURE, 0, _("Only root is allowed to use this option!"));
 295       else
 296         {
 297           int sock = nscd_open_socket ();
 298           request_header req;
 299           ssize_t nbytes;
 300
 301           if (sock == -1)
 302             exit (EXIT_FAILURE);
 303
 304           if (strcmp (arg, "passwd") == 0)
 305             req.key_len = sizeof "passwd";
 306           else if (strcmp (arg, "group") == 0)
 307             req.key_len = sizeof "group";
 308           else if (strcmp (arg, "hosts") == 0)
 309             req.key_len = sizeof "hosts";
 310           else
 311             return ARGP_ERR_UNKNOWN;
 312
 313           req.version = NSCD_VERSION;
 314           req.type = INVALIDATE;
 315           nbytes = TEMP_FAILURE_RETRY (write (sock, &req,
 316                                               sizeof (request_header)));
 317           if (nbytes != sizeof (request_header))
 318             {
 319               close (sock);
 320               exit (EXIT_FAILURE);
 321             }
 322
 323           nbytes = TEMP_FAILURE_RETRY (write (sock, (void *)arg, req.key_len));
 324
 325           close (sock);
 326
 327           exit (nbytes != req.key_len ? EXIT_FAILURE : EXIT_SUCCESS);
 328         }
 329
 330     case 't':
 331       nthreads = atol (arg);
 332       break;
 333
 334     case 'S':
 335       if (strcmp (arg, "passwd,yes") == 0)
 336         secure_in_use = secure[pwddb] = 1;
 337       else if (strcmp (arg, "group,yes") == 0)
 338         secure_in_use = secure[grpdb] = 1;
 339       else if (strcmp (arg, "hosts,yes") == 0)
 340         secure_in_use = secure[hstdb] = 1;
 341       break;
 342
 343     default:
 344       return ARGP_ERR_UNKNOWN;
 345     }
 346
 347   return 0;
 348 }
 349
 350 /* Print the version information.  */
 351 static void
 352 print_version (FILE *stream, struct argp_state *state)
 353 {
 354   fprintf (stream, "nscd (GNU %s) %s\n", PACKAGE, VERSION);
 355   fprintf (stream, gettext ("\
 356 Copyright (C) %s Free Software Foundation, Inc.\n\
 357 This is free software; see the source for copying conditions.  There is NO\n\
 358 warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n\
 359 "), "2003");
 360   fprintf (stream, gettext ("Written by %s.\n"),
 361            "Thorsten Kukuk and Ulrich Drepper");
 362 }
 363
 364
 365 /* Create a socket connected to a name.  */
 366 int
 367 nscd_open_socket (void)
 368 {
 369   struct sockaddr_un addr;
 370   int sock;
 371
 372   sock = socket (PF_UNIX, SOCK_STREAM, 0);
 373   if (sock < 0)
 374     return -1;
 375
 376   addr.sun_family = AF_UNIX;
 377   assert (sizeof (addr.sun_path) >= sizeof (_PATH_NSCDSOCKET));
 378   strcpy (addr.sun_path, _PATH_NSCDSOCKET);
 379   if (connect (sock, (struct sockaddr *) &addr, sizeof (addr)) < 0)
 380     {
 381       close (sock);
 382       return -1;
 383     }
 384
 385   return sock;
 386 }
 387
 388 /* Cleanup.  */
 389 void
 390 termination_handler (int signum)
 391 {
 392   close_sockets ();
 393
 394   /* Clean up the file created by `bind'.  */
 395   unlink (_PATH_NSCDSOCKET);
 396
 397   /* Clean up pid file.  */
 398   unlink (_PATH_NSCDPID);
 399
 400   exit (EXIT_SUCCESS);
 401 }
 402
 403 /* Returns 1 if the process in pid file FILE is running, 0 if not.  */
 404 static int
 405 check_pid (const char *file)
 406 {
 407   FILE *fp;
 408
 409   fp = fopen (file, "r");
 410   if (fp)
 411     {
 412       pid_t pid;
 413       int n;
 414
 415       n = fscanf (fp, "%d", &pid);
 416       fclose (fp);
 417
 418       if (n != 1 || kill (pid, 0) == 0)
 419         return 1;
 420     }
 421
 422   return 0;
 423 }
 424
 425 /* Write the current process id to the file FILE.
 426    Returns 0 if successful, -1 if not.  */
 427 static int
 428 write_pid (const char *file)
 429 {
 430   FILE *fp;
 431
 432   fp = fopen (file, "w");
 433   if (fp == NULL)
 434     return -1;
 435
 436   fprintf (fp, "%d\n", getpid ());
 437   if (fflush (fp) || ferror (fp))
 438     return -1;
 439
 440   fclose (fp);
 441
 442   return 0;
 443 }