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