nscd/nscd.c

   1 /* Copyright (c) 1998-2003, 2004 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/mman.h>
  40 #include <sys/socket.h>
  41 #include <sys/stat.h>
  42 #include <sys/uio.h>
  43 #include <sys/un.h>
  44
  45 #include "dbg_log.h"
  46 #include "nscd.h"
  47 #include "../nss/nsswitch.h"
  48 #include <device-nrs.h>
  49
  50 /* Get libc version number.  */
  51 #include <version.h>
  52
  53 #define PACKAGE _libc_intl_domainname
  54
  55 /* Structure used by main() thread to keep track of the number of
  56    active threads.  Used to limit how many threads it will create
  57    and under a shutdown condition to wait till all in-progress
  58    requests have finished before "turning off the lights".  */
  59
  60 typedef struct
  61 {
  62   int             num_active;
  63   pthread_cond_t  thread_exit_cv;
  64   pthread_mutex_t mutex;
  65 } thread_info_t;
  66
  67 thread_info_t thread_info;
  68
  69 int do_shutdown;
  70 int disabled_passwd;
  71 int disabled_group;
  72 int go_background = 1;
  73
  74 int secure_in_use;
  75 static const char *conffile = _PATH_NSCDCONF;
  76
  77 time_t start_time;
  78
  79 uintptr_t pagesize_m1;
  80
  81 static int check_pid (const char *file);
  82 static int write_pid (const char *file);
  83
  84 /* Name and version of program.  */
  85 static void print_version (FILE *stream, struct argp_state *state);
  86 void (*argp_program_version_hook) (FILE *, struct argp_state *) = print_version;
  87
  88 /* Definitions of arguments for argp functions.  */
  89 static const struct argp_option options[] =
  90 {
  91   { "config-file", 'f', N_("NAME"), 0,
  92     N_("Read configuration data from NAME") },
  93   { "debug", 'd', NULL, 0,
  94     N_("Do not fork and display messages on the current tty") },
  95   { "nthreads", 't', N_("NUMBER"), 0, N_("Start NUMBER threads") },
  96   { "shutdown", 'K', NULL, 0, N_("Shut the server down") },
  97   { "statistic", 'g', NULL, 0, N_("Print current configuration statistic") },
  98   { "invalidate", 'i', N_("TABLE"), 0,
  99     N_("Invalidate the specified cache") },
 100   { "secure", 'S', N_("TABLE,yes"), 0, N_("Use separate cache for each user")},
 101   { NULL, 0, NULL, 0, NULL }
 102 };
 103
 104 /* Short description of program.  */
 105 static const char doc[] = N_("Name Service Cache Daemon.");
 106
 107 /* Prototype for option handler.  */
 108 static error_t parse_opt (int key, char *arg, struct argp_state *state);
 109
 110 /* Data structure to communicate with argp functions.  */
 111 static struct argp argp =
 112 {
 113   options, parse_opt, NULL, doc,
 114 };
 115
 116 /* True if only statistics are requested.  */
 117 static bool get_stats;
 118
 119 int
 120 main (int argc, char **argv)
 121 {
 122   int remaining;
 123
 124   /* Set locale via LC_ALL.  */
 125   setlocale (LC_ALL, "");
 126   /* Set the text message domain.  */
 127   textdomain (PACKAGE);
 128
 129   /* Parse and process arguments.  */
 130   argp_parse (&argp, argc, argv, 0, &remaining, NULL);
 131
 132   if (remaining != argc)
 133     {
 134       error (0, 0, gettext ("wrong number of arguments"));
 135       argp_help (&argp, stdout, ARGP_HELP_SEE, program_invocation_short_name);
 136       exit (EXIT_FAILURE);
 137     }
 138
 139   /* Read the configuration file.  */
 140   if (nscd_parse_file (conffile, dbs) != 0)
 141     {
 142       /* We couldn't read the configuration file.  We don't start the
 143          server.  */
 144       dbg_log (_("cannot read configuration file; this is fatal"));
 145       exit (1);
 146     }
 147
 148   /* Do we only get statistics?  */
 149   if (get_stats)
 150     /* Does not return.  */
 151     receive_print_stats ();
 152
 153   /* Check if we are already running. */
 154   if (check_pid (_PATH_NSCDPID))
 155     error (EXIT_FAILURE, 0, _("already running"));
 156
 157   /* Remember when we started.  */
 158   start_time = time (NULL);
 159
 160   /* Determine page size.  */
 161   pagesize_m1 = getpagesize () - 1;
 162
 163   /* Behave like a daemon.  */
 164   if (go_background)
 165     {
 166       int i;
 167
 168       pid_t pid = fork ();
 169       if (pid == -1)
 170         error (EXIT_FAILURE, errno, _("cannot fork"));
 171       if (pid != 0)
 172         exit (0);
 173
 174       int nullfd = open (_PATH_DEVNULL, O_RDWR);
 175       if (nullfd != -1)
 176         {
 177           struct stat64 st;
 178
 179           if (fstat64 (nullfd, &st) == 0 && S_ISCHR (st.st_mode) != 0
 180 #if defined DEV_NULL_MAJOR && defined DEV_NULL_MINOR
 181               && st.st_rdev == makedev (DEV_NULL_MAJOR, DEV_NULL_MINOR)
 182 #endif
 183               )
 184             {
 185               /* It is the /dev/null special device alright.  */
 186               (void) dup2 (nullfd, STDIN_FILENO);
 187               (void) dup2 (nullfd, STDOUT_FILENO);
 188               (void) dup2 (nullfd, STDERR_FILENO);
 189
 190               if (nullfd > 2)
 191                 close (nullfd);
 192             }
 193           else
 194             {
 195               /* Ugh, somebody is trying to play a trick on us.  */
 196               close (nullfd);
 197               nullfd = -1;
 198             }
 199         }
 200       int min_close_fd = nullfd == -1 ? 0 : STDERR_FILENO + 1;
 201
 202       DIR *d = opendir ("/proc/self/fd");
 203       if (d != NULL)
 204         {
 205           struct dirent64 *dirent;
 206           int dfdn = dirfd (d);
 207
 208           while ((dirent = readdir64 (d)) != NULL)
 209             {
 210               char *endp;
 211               long int fdn = strtol (dirent->d_name, &endp, 10);
 212
 213               if (*endp == '\0' && fdn != dfdn && fdn >= min_close_fd)
 214                 close ((int) fdn);
 215             }
 216
 217           closedir (d);
 218         }
 219       else
 220         for (i = min_close_fd; i < getdtablesize (); i++)
 221           close (i);
 222
 223       pid = fork ();
 224       if (pid == -1)
 225         error (EXIT_FAILURE, errno, _("cannot fork"));
 226       if (pid != 0)
 227         exit (0);
 228
 229       setsid ();
 230
 231       chdir ("/");
 232
 233       openlog ("nscd", LOG_CONS | LOG_ODELAY, LOG_DAEMON);
 234
 235       if (write_pid (_PATH_NSCDPID) < 0)
 236         dbg_log ("%s: %s", _PATH_NSCDPID, strerror (errno));
 237
 238       if (!init_logfile ())
 239         dbg_log (_("Could not create log file"));
 240
 241       /* Ignore job control signals.  */
 242       signal (SIGTTOU, SIG_IGN);
 243       signal (SIGTTIN, SIG_IGN);
 244       signal (SIGTSTP, SIG_IGN);
 245     }
 246
 247   signal (SIGINT, termination_handler);
 248   signal (SIGQUIT, termination_handler);
 249   signal (SIGTERM, termination_handler);
 250   signal (SIGPIPE, SIG_IGN);
 251
 252   /* Cleanup files created by a previous 'bind'.  */
 253   unlink (_PATH_NSCDSOCKET);
 254
 255   /* Make sure we do not get recursive calls.  */
 256   __nss_disable_nscd ();
 257
 258   /* Init databases.  */
 259   nscd_init ();
 260
 261   /* Handle incoming requests */
 262   start_threads ();
 263
 264   return 0;
 265 }
 266
 267
 268 /* Handle program arguments.  */
 269 static error_t
 270 parse_opt (int key, char *arg, struct argp_state *state)
 271 {
 272   switch (key)
 273     {
 274     case 'd':
 275       ++debug_level;
 276       go_background = 0;
 277       break;
 278
 279     case 'f':
 280       conffile = arg;
 281       break;
 282
 283     case 'K':
 284       if (getuid () != 0)
 285         error (EXIT_FAILURE, 0, _("Only root is allowed to use this option!"));
 286       {
 287         int sock = nscd_open_socket ();
 288         request_header req;
 289         ssize_t nbytes;
 290
 291         if (sock == -1)
 292           exit (EXIT_FAILURE);
 293
 294         req.version = NSCD_VERSION;
 295         req.type = SHUTDOWN;
 296         req.key_len = 0;
 297         nbytes = TEMP_FAILURE_RETRY (write (sock, &req,
 298                                             sizeof (request_header)));
 299         close (sock);
 300         exit (nbytes != sizeof (request_header) ? EXIT_FAILURE : EXIT_SUCCESS);
 301       }
 302
 303     case 'g':
 304       get_stats = true;
 305       break;
 306
 307     case 'i':
 308       if (getuid () != 0)
 309         error (EXIT_FAILURE, 0, _("Only root is allowed to use this option!"));
 310       else
 311         {
 312           int sock = nscd_open_socket ();
 313
 314           if (sock == -1)
 315             exit (EXIT_FAILURE);
 316
 317           request_header req;
 318           ssize_t nbytes;
 319           struct iovec iov[2];
 320
 321           if (strcmp (arg, "passwd") == 0)
 322             req.key_len = sizeof "passwd";
 323           else if (strcmp (arg, "group") == 0)
 324             req.key_len = sizeof "group";
 325           else if (strcmp (arg, "hosts") == 0)
 326             req.key_len = sizeof "hosts";
 327           else
 328             return ARGP_ERR_UNKNOWN;
 329
 330           req.version = NSCD_VERSION;
 331           req.type = INVALIDATE;
 332
 333           iov[0].iov_base = &req;
 334           iov[0].iov_len = sizeof (req);
 335           iov[1].iov_base = (void *) key;
 336           iov[1].iov_len = req.key_len;
 337
 338           nbytes = TEMP_FAILURE_RETRY (writev (sock, iov, 2));
 339
 340           close (sock);
 341
 342           exit (nbytes != iov[0].iov_len + iov[1].iov_len
 343                 ? EXIT_FAILURE : EXIT_SUCCESS);
 344         }
 345
 346     case 't':
 347       nthreads = atol (arg);
 348       break;
 349
 350     case 'S':
 351       if (strcmp (arg, "passwd,yes") == 0)
 352         secure_in_use = dbs[pwddb].secure = 1;
 353       else if (strcmp (arg, "group,yes") == 0)
 354         secure_in_use = dbs[grpdb].secure = 1;
 355       else if (strcmp (arg, "hosts,yes") == 0)
 356         secure_in_use = dbs[hstdb].secure = 1;
 357       break;
 358
 359     default:
 360       return ARGP_ERR_UNKNOWN;
 361     }
 362
 363   return 0;
 364 }
 365
 366 /* Print the version information.  */
 367 static void
 368 print_version (FILE *stream, struct argp_state *state)
 369 {
 370   fprintf (stream, "nscd (GNU %s) %s\n", PACKAGE, VERSION);
 371   fprintf (stream, gettext ("\
 372 Copyright (C) %s Free Software Foundation, Inc.\n\
 373 This is free software; see the source for copying conditions.  There is NO\n\
 374 warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n\
 375 "), "2004");
 376   fprintf (stream, gettext ("Written by %s.\n"),
 377            "Thorsten Kukuk and Ulrich Drepper");
 378 }
 379
 380
 381 /* Create a socket connected to a name.  */
 382 int
 383 nscd_open_socket (void)
 384 {
 385   struct sockaddr_un addr;
 386   int sock;
 387
 388   sock = socket (PF_UNIX, SOCK_STREAM, 0);
 389   if (sock < 0)
 390     return -1;
 391
 392   addr.sun_family = AF_UNIX;
 393   assert (sizeof (addr.sun_path) >= sizeof (_PATH_NSCDSOCKET));
 394   strcpy (addr.sun_path, _PATH_NSCDSOCKET);
 395   if (connect (sock, (struct sockaddr *) &addr, sizeof (addr)) < 0)
 396     {
 397       close (sock);
 398       return -1;
 399     }
 400
 401   return sock;
 402 }
 403
 404 /* Cleanup.  */
 405 void
 406 termination_handler (int signum)
 407 {
 408   close_sockets ();
 409
 410   /* Clean up the file created by 'bind'.  */
 411   unlink (_PATH_NSCDSOCKET);
 412
 413   /* Clean up pid file.  */
 414   unlink (_PATH_NSCDPID);
 415
 416   // XXX Terminate threads.
 417
 418   /* Synchronize memory.  */
 419   for (int cnt = 0; cnt < lastdb; ++cnt)
 420     if (dbs[cnt].persistent)
 421       // XXX async OK?
 422       msync (dbs[cnt].head, dbs[cnt].memsize, MS_ASYNC);
 423
 424   _exit (EXIT_SUCCESS);
 425 }
 426
 427 /* Returns 1 if the process in pid file FILE is running, 0 if not.  */
 428 static int
 429 check_pid (const char *file)
 430 {
 431   FILE *fp;
 432
 433   fp = fopen (file, "r");
 434   if (fp)
 435     {
 436       pid_t pid;
 437       int n;
 438
 439       n = fscanf (fp, "%d", &pid);
 440       fclose (fp);
 441
 442       if (n != 1 || kill (pid, 0) == 0)
 443         return 1;
 444     }
 445
 446   return 0;
 447 }
 448
 449 /* Write the current process id to the file FILE.
 450    Returns 0 if successful, -1 if not.  */
 451 static int
 452 write_pid (const char *file)
 453 {
 454   FILE *fp;
 455
 456   fp = fopen (file, "w");
 457   if (fp == NULL)
 458     return -1;
 459
 460   fprintf (fp, "%d\n", getpid ());
 461   if (fflush (fp) || ferror (fp))
 462     return -1;
 463
 464   fclose (fp);
 465
 466   return 0;
 467 }