nss/makedb.c

   1 /* Create simple DB database from textual input.
   2    Copyright (C) 1996-2012 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1996.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, see
  18    <http://www.gnu.org/licenses/>.  */
  19
  20 #include <argp.h>
  21 #include <assert.h>
  22 #include <ctype.h>
  23 #include <errno.h>
  24 #include <error.h>
  25 #include <fcntl.h>
  26 #include <inttypes.h>
  27 #include <libintl.h>
  28 #include <locale.h>
  29 #include <search.h>
  30 #include <stdbool.h>
  31 #include <stdio.h>
  32 #include <stdlib.h>
  33 #include <string.h>
  34 #include <unistd.h>
  35 #include <sys/mman.h>
  36 #include <sys/param.h>
  37 #include <sys/stat.h>
  38 #include <sys/uio.h>
  39 #include "nss_db/nss_db.h"
  40
  41 /* Get libc version number.  */
  42 #include "../version.h"
  43
  44 /* The hashing function we use.  */
  45 #include "../intl/hash-string.h"
  46
  47 /* SELinux support.  */
  48 #ifdef HAVE_SELINUX
  49 # include <selinux/selinux.h>
  50 #endif
  51
  52 #ifndef MAP_POPULATE
  53 # define MAP_POPULATE 0
  54 #endif
  55
  56 #define PACKAGE _libc_intl_domainname
  57
  58 /* List of data bases.  */
  59 struct database
  60 {
  61   char dbid;
  62   bool extra_string;
  63   struct database *next;
  64   void *entries;
  65   size_t nentries;
  66   size_t nhashentries;
  67   stridx_t *hashtable;
  68   size_t keystrlen;
  69   stridx_t *keyidxtab;
  70   char *keystrtab;
  71 } *databases;
  72 static size_t ndatabases;
  73 static size_t nhashentries_total;
  74 static size_t valstrlen;
  75 static void *valstrtree;
  76 static char *valstrtab;
  77 static size_t extrastrlen;
  78
  79 /* Database entry.  */
  80 struct dbentry
  81 {
  82   stridx_t validx;
  83   uint32_t hashval;
  84   char str[0];
  85 };
  86
  87 /* Stored string entry.  */
  88 struct valstrentry
  89 {
  90   stridx_t idx;
  91   bool extra_string;
  92   char str[0];
  93 };
  94
  95
  96 /* True if any entry has been added.  */
  97 static bool any_dbentry;
  98
  99 /* If non-zero convert key to lower case.  */
 100 static int to_lowercase;
 101
 102 /* If non-zero print content of input file, one entry per line.  */
 103 static int do_undo;
 104
 105 /* If non-zero do not print informational messages.  */
 106 static int be_quiet;
 107
 108 /* Name of output file.  */
 109 static const char *output_name;
 110
 111 /* Name and version of program.  */
 112 static void print_version (FILE *stream, struct argp_state *state);
 113 void (*argp_program_version_hook) (FILE *, struct argp_state *) = print_version;
 114
 115 /* Definitions of arguments for argp functions.  */
 116 static const struct argp_option options[] =
 117 {
 118   { "fold-case", 'f', NULL, 0, N_("Convert key to lower case") },
 119   { "output", 'o', N_("NAME"), 0, N_("Write output to file NAME") },
 120   { "quiet", 'q', NULL, 0,
 121     N_("Do not print messages while building database") },
 122   { "undo", 'u', NULL, 0,
 123     N_("Print content of database file, one entry a line") },
 124   { "generated", 'g', N_("CHAR"), 0,
 125     N_("Generated line not part of iteration") },
 126   { NULL, 0, NULL, 0, NULL }
 127 };
 128
 129 /* Short description of program.  */
 130 static const char doc[] = N_("Create simple database from textual input.");
 131
 132 /* Strings for arguments in help texts.  */
 133 static const char args_doc[] = N_("\
 134 INPUT-FILE OUTPUT-FILE\n-o OUTPUT-FILE INPUT-FILE\n-u INPUT-FILE");
 135
 136 /* Prototype for option handler.  */
 137 static error_t parse_opt (int key, char *arg, struct argp_state *state);
 138
 139 /* Function to print some extra text in the help message.  */
 140 static char *more_help (int key, const char *text, void *input);
 141
 142 /* Data structure to communicate with argp functions.  */
 143 static struct argp argp =
 144 {
 145   options, parse_opt, args_doc, doc, NULL, more_help
 146 };
 147
 148
 149 /* List of databases which are not part of the iteration table.  */
 150 static struct db_option
 151 {
 152   char dbid;
 153   struct db_option *next;
 154 } *db_options;
 155
 156
 157 /* Prototypes for local functions.  */
 158 static int process_input (FILE *input, const char *inname,
 159                           int to_lowercase, int be_quiet);
 160 static int print_database (int fd);
 161 static void compute_tables (void);
 162 static int write_output (int fd);
 163
 164 /* SELinux support.  */
 165 #ifdef HAVE_SELINUX
 166 /* Set the SELinux file creation context for the given file. */
 167 static void set_file_creation_context (const char *outname, mode_t mode);
 168 static void reset_file_creation_context (void);
 169 #else
 170 # define set_file_creation_context(_outname,_mode)
 171 # define reset_file_creation_context()
 172 #endif
 173
 174
 175 /* External functions.  */
 176 extern void *xmalloc (size_t n)
 177   __attribute_malloc__ __attribute_alloc_size (1);
 178 extern void *xcalloc (size_t n, size_t s)
 179   __attribute_malloc__ __attribute_alloc_size (1, 2);
 180
 181
 182 int
 183 main (int argc, char *argv[])
 184 {
 185   const char *input_name;
 186   FILE *input_file;
 187   int remaining;
 188   int mode = 0644;
 189
 190   /* Set locale via LC_ALL.  */
 191   setlocale (LC_ALL, "");
 192
 193   /* Set the text message domain.  */
 194   textdomain (_libc_intl_domainname);
 195
 196   /* Initialize local variables.  */
 197   input_name = NULL;
 198
 199   /* Parse and process arguments.  */
 200   argp_parse (&argp, argc, argv, 0, &remaining, NULL);
 201
 202   /* Determine file names.  */
 203   if (do_undo || output_name != NULL)
 204     {
 205       if (remaining + 1 != argc)
 206         {
 207         wrong_arguments:
 208           error (0, 0, gettext ("wrong number of arguments"));
 209           argp_help (&argp, stdout, ARGP_HELP_SEE,
 210                      program_invocation_short_name);
 211           exit (1);
 212         }
 213       input_name = argv[remaining];
 214     }
 215   else
 216     {
 217       if (remaining + 2 != argc)
 218         goto wrong_arguments;
 219
 220       input_name = argv[remaining++];
 221       output_name = argv[remaining];
 222     }
 223
 224   /* Special handling if we are asked to print the database.  */
 225   if (do_undo)
 226     {
 227       int fd = open (input_name, O_RDONLY);
 228       if (fd == -1)
 229         error (EXIT_FAILURE, errno, gettext ("cannot open database file `%s'"),
 230                input_name);
 231
 232       int status = print_database (fd);
 233
 234       close (fd);
 235
 236       return status;
 237     }
 238
 239   /* Open input file.  */
 240   if (strcmp (input_name, "-") == 0 || strcmp (input_name, "/dev/stdin") == 0)
 241     input_file = stdin;
 242   else
 243     {
 244       struct stat64 st;
 245
 246       input_file = fopen64 (input_name, "r");
 247       if (input_file == NULL)
 248         error (EXIT_FAILURE, errno, gettext ("cannot open input file `%s'"),
 249                input_name);
 250
 251       /* Get the access rights from the source file.  The output file should
 252          have the same.  */
 253       if (fstat64 (fileno (input_file), &st) >= 0)
 254         mode = st.st_mode & ACCESSPERMS;
 255     }
 256
 257   /* Start the real work.  */
 258   int status = process_input (input_file, input_name, to_lowercase, be_quiet);
 259
 260   /* Close files.  */
 261   if (input_file != stdin)
 262     fclose (input_file);
 263
 264   /* No need to continue when we did not read the file successfully.  */
 265   if (status != EXIT_SUCCESS)
 266     return status;
 267
 268   /* Bail out if nothing is to be done.  */
 269   if (!any_dbentry)
 270     {
 271       if (be_quiet)
 272         return EXIT_SUCCESS;
 273       else
 274         error (EXIT_SUCCESS, 0, gettext ("no entries to be processed"));
 275     }
 276
 277   /* Compute hash and string tables.  */
 278   compute_tables ();
 279
 280   /* Open output file.  This must not be standard output so we don't
 281      handle "-" and "/dev/stdout" special.  */
 282   char *tmp_output_name;
 283   if (asprintf (&tmp_output_name, "%s.XXXXXX", output_name) == -1)
 284     error (EXIT_FAILURE, errno, gettext ("cannot create temporary file name"));
 285
 286   set_file_creation_context (output_name, mode);
 287   int fd = mkstemp (tmp_output_name);
 288   reset_file_creation_context ();
 289   if (fd == -1)
 290     error (EXIT_FAILURE, errno, gettext ("cannot create temporary file"));
 291
 292   status = write_output (fd);
 293
 294   if (status == EXIT_SUCCESS)
 295     {
 296       struct stat64 st;
 297
 298       if (fstat64 (fd, &st) == 0)
 299         {
 300           if ((st.st_mode & ACCESSPERMS) != mode)
 301             /* We ignore problems with changing the mode.  */
 302             fchmod (fd, mode);
 303         }
 304       else
 305         {
 306           error (0, errno, gettext ("cannot stat newly created file"));
 307           status = EXIT_FAILURE;
 308         }
 309     }
 310
 311   close (fd);
 312
 313   if (status == EXIT_SUCCESS)
 314     {
 315       if (rename (tmp_output_name, output_name) != 0)
 316         {
 317           error (0, errno, gettext ("cannot rename temporary file"));
 318           status = EXIT_FAILURE;
 319           goto do_unlink;
 320         }
 321     }
 322   else
 323   do_unlink:
 324     unlink (tmp_output_name);
 325
 326   return status;
 327 }
 328
 329
 330 /* Handle program arguments.  */
 331 static error_t
 332 parse_opt (int key, char *arg, struct argp_state *state)
 333 {
 334   struct db_option *newp;
 335
 336   switch (key)
 337     {
 338     case 'f':
 339       to_lowercase = 1;
 340       break;
 341     case 'o':
 342       output_name = arg;
 343       break;
 344     case 'q':
 345       be_quiet = 1;
 346       break;
 347     case 'u':
 348       do_undo = 1;
 349       break;
 350     case 'g':
 351       newp = xmalloc (sizeof (*newp));
 352       newp->dbid = arg[0];
 353       newp->next = db_options;
 354       db_options = newp;
 355       break;
 356     default:
 357       return ARGP_ERR_UNKNOWN;
 358     }
 359   return 0;
 360 }
 361
 362
 363 static char *
 364 more_help (int key, const char *text, void *input)
 365 {
 366   switch (key)
 367     {
 368     case ARGP_KEY_HELP_EXTRA:
 369       /* We print some extra information.  */
 370       return strdup (gettext ("\
 371 For bug reporting instructions, please see:\n\
 372 <http://www.gnu.org/software/libc/bugs.html>.\n"));
 373     default:
 374       break;
 375     }
 376   return (char *) text;
 377 }
 378
 379 /* Print the version information.  */
 380 static void
 381 print_version (FILE *stream, struct argp_state *state)
 382 {
 383   fprintf (stream, "makedb (GNU %s) %s\n", PACKAGE, VERSION);
 384   fprintf (stream, gettext ("\
 385 Copyright (C) %s Free Software Foundation, Inc.\n\
 386 This is free software; see the source for copying conditions.  There is NO\n\
 387 warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n\
 388 "), "2012");
 389   fprintf (stream, gettext ("Written by %s.\n"), "Ulrich Drepper");
 390 }
 391
 392
 393 static int
 394 dbentry_compare (const void *p1, const void *p2)
 395 {
 396   const struct dbentry *d1 = (const struct dbentry *) p1;
 397   const struct dbentry *d2 = (const struct dbentry *) p2;
 398
 399   if (d1->hashval != d2->hashval)
 400     return d1->hashval < d2->hashval ? -1 : 1;
 401
 402   return strcmp (d1->str, d2->str);
 403 }
 404
 405
 406 static int
 407 valstr_compare (const void *p1, const void *p2)
 408 {
 409   const struct valstrentry *d1 = (const struct valstrentry *) p1;
 410   const struct valstrentry *d2 = (const struct valstrentry *) p2;
 411
 412   return strcmp (d1->str, d2->str);
 413 }
 414
 415
 416 static int
 417 process_input (input, inname, to_lowercase, be_quiet)
 418      FILE *input;
 419      const char *inname;
 420      int to_lowercase;
 421      int be_quiet;
 422 {
 423   char *line;
 424   size_t linelen;
 425   int status;
 426   size_t linenr;
 427
 428   line = NULL;
 429   linelen = 0;
 430   status = EXIT_SUCCESS;
 431   linenr = 0;
 432
 433   struct database *last_database = NULL;
 434
 435   while (!feof_unlocked (input))
 436     {
 437       ssize_t n = getline (&line, &linelen, input);
 438       if (n < 0)
 439         /* This means end of file or some bug.  */
 440         break;
 441       if (n == 0)
 442         /* Short read.  Probably interrupted system call. */
 443         continue;
 444
 445       ++linenr;
 446
 447       if (line[n - 1] == '\n')
 448         /* Remove trailing newline.  */
 449         line[--n] = '\0';
 450
 451       char *cp = line;
 452       while (isspace (*cp))
 453         ++cp;
 454
 455       if (*cp == '#' || *cp == '\0')
 456         /* First non-space character in line '#': it's a comment.
 457            Also go to the next line if it is empty except for whitespaces. */
 458         continue;
 459
 460       /* Skip over the character indicating the database so that it is not
 461          affected by TO_LOWERCASE.  */
 462       char *key = cp++;
 463       while (*cp != '\0' && !isspace (*cp))
 464         {
 465           if (to_lowercase)
 466             *cp = tolower (*cp);
 467           ++cp;
 468         }
 469
 470       if (*cp == '\0')
 471         /* It's a line without a value field.  */
 472         continue;
 473
 474       *cp++ = '\0';
 475       size_t keylen = cp - key;
 476
 477       while (isspace (*cp))
 478         ++cp;
 479
 480       char *data = cp;
 481       size_t datalen = (&line[n] - cp) + 1;
 482
 483       /* Find the database.  */
 484       if (last_database == NULL || last_database->dbid != key[0])
 485         {
 486           last_database = databases;
 487           while (last_database != NULL && last_database->dbid != key[0])
 488             last_database = last_database->next;
 489
 490           if (last_database == NULL)
 491             {
 492               last_database = xmalloc (sizeof (*last_database));
 493               last_database->dbid = key[0];
 494               last_database->extra_string = false;
 495               last_database->next = databases;
 496               last_database->entries = NULL;
 497               last_database->nentries = 0;
 498               last_database->keystrlen = 0;
 499               databases = last_database;
 500
 501               struct db_option *runp = db_options;
 502               while (runp != NULL)
 503                 if (runp->dbid == key[0])
 504                   {
 505                     last_database->extra_string = true;
 506                     break;
 507                   }
 508                 else
 509                   runp = runp->next;
 510             }
 511         }
 512
 513       /* Skip the database selector.  */
 514       ++key;
 515       --keylen;
 516
 517       /* Store the data.  */
 518       struct valstrentry *nentry = xmalloc (sizeof (struct valstrentry)
 519                                             + datalen);
 520       if (last_database->extra_string)
 521         nentry->idx = extrastrlen;
 522       else
 523         nentry->idx = valstrlen;
 524       nentry->extra_string = last_database->extra_string;
 525       memcpy (nentry->str, data, datalen);
 526
 527       struct valstrentry **fdata = tsearch (nentry, &valstrtree,
 528                                             valstr_compare);
 529       if (fdata == NULL)
 530         error (EXIT_FAILURE, errno, gettext ("cannot create search tree"));
 531
 532       if (*fdata != nentry)
 533         {
 534           /* We can reuse a string.  */
 535           free (nentry);
 536           nentry = *fdata;
 537         }
 538       else
 539         if (last_database->extra_string)
 540           extrastrlen += datalen;
 541         else
 542           valstrlen += datalen;
 543
 544       /* Store the key.  */
 545       struct dbentry *newp = xmalloc (sizeof (struct dbentry) + keylen);
 546       newp->validx = nentry->idx;
 547       newp->hashval = __hash_string (key);
 548       memcpy (newp->str, key, keylen);
 549
 550       struct dbentry **found = tsearch (newp, &last_database->entries,
 551                                         dbentry_compare);
 552       if (found == NULL)
 553         error (EXIT_FAILURE, errno, gettext ("cannot create search tree"));
 554
 555       if (*found != newp)
 556         {
 557           free (newp);
 558           if (!be_quiet)
 559             error_at_line (0, 0, inname, linenr, gettext ("duplicate key"));
 560           continue;
 561         }
 562
 563       ++last_database->nentries;
 564       last_database->keystrlen += keylen;
 565
 566       any_dbentry = true;
 567     }
 568
 569   if (ferror_unlocked (input))
 570     {
 571       error (0, 0, gettext ("problems while reading `%s'"), inname);
 572       status = EXIT_FAILURE;
 573     }
 574
 575   return status;
 576 }
 577
 578
 579 static void
 580 copy_valstr (const void *nodep, const VISIT which, const int depth)
 581 {
 582   if (which != leaf && which != postorder)
 583     return;
 584
 585   const struct valstrentry *p = *(const struct valstrentry **) nodep;
 586
 587   strcpy (valstrtab + (p->extra_string ? valstrlen : 0) + p->idx, p->str);
 588 }
 589
 590
 591 static int
 592 is_prime (size_t candidate)
 593 {
 594   /* No even number and none less than 10 will be passed here.  */
 595   size_t divn = 3;
 596   size_t sq = divn * divn;
 597
 598   while (sq < candidate && candidate % divn != 0)
 599     {
 600       ++divn;
 601       sq += 4 * divn;
 602       ++divn;
 603     }
 604
 605   return candidate % divn != 0;
 606 }
 607
 608
 609 static size_t
 610 next_prime (size_t seed)
 611 {
 612   /* Make it definitely odd.  */
 613   seed |= 1;
 614
 615   while (!is_prime (seed))
 616     seed += 2;
 617
 618   return seed;
 619 }
 620
 621
 622 static void
 623 compute_tables (void)
 624 {
 625   valstrtab = xmalloc (roundup (valstrlen + extrastrlen, sizeof (stridx_t)));
 626   while ((valstrlen + extrastrlen) % sizeof (stridx_t) != 0)
 627     valstrtab[valstrlen++] = '\0';
 628   twalk (valstrtree, copy_valstr);
 629
 630   static struct database *db;
 631   for (db = databases; db != NULL; db = db->next)
 632     if (db->nentries != 0)
 633       {
 634         ++ndatabases;
 635
 636         /* We simply use an odd number large than twice the number of
 637            elements to store in the hash table for the size.  This gives
 638            enough efficiency.  */
 639 #define TEST_RANGE 30
 640         size_t nhashentries_min = next_prime (db->nentries < TEST_RANGE
 641                                               ? db->nentries
 642                                               : db->nentries * 2 - TEST_RANGE);
 643         size_t nhashentries_max = MAX (nhashentries_min, db->nentries * 4);
 644         size_t nhashentries_best = nhashentries_min;
 645         size_t chainlength_best = db->nentries;
 646
 647         db->hashtable = xmalloc (2 * nhashentries_max * sizeof (stridx_t)
 648                                  + db->keystrlen);
 649         db->keyidxtab = db->hashtable + nhashentries_max;
 650         db->keystrtab = (char *) (db->keyidxtab + nhashentries_max);
 651
 652         static size_t max_chainlength;
 653         static char *wp;
 654         static size_t nhashentries;
 655         static bool copy_string;
 656
 657         void add_key(const void *nodep, const VISIT which, const int depth)
 658         {
 659           if (which != leaf && which != postorder)
 660             return;
 661
 662           const struct dbentry *dbe = *(const struct dbentry **) nodep;
 663
 664           ptrdiff_t stridx;
 665           if (copy_string)
 666             {
 667               stridx = wp - db->keystrtab;
 668               wp = stpcpy (wp, dbe->str) + 1;
 669             }
 670           else
 671             stridx = 0;
 672
 673           size_t hidx = dbe->hashval % nhashentries;
 674           size_t hval2 = 1 + dbe->hashval % (nhashentries - 2);
 675           size_t chainlength = 0;
 676
 677           while (db->hashtable[hidx] != ~((stridx_t) 0))
 678             {
 679               ++chainlength;
 680               if ((hidx += hval2) >= nhashentries)
 681                 hidx -= nhashentries;
 682             }
 683
 684           db->hashtable[hidx] = ((db->extra_string ? valstrlen : 0)
 685                                  + dbe->validx);
 686           db->keyidxtab[hidx] = stridx;
 687
 688           max_chainlength = MAX (max_chainlength, chainlength);
 689         }
 690
 691         copy_string = false;
 692         nhashentries = nhashentries_min;
 693         for (size_t cnt = 0; cnt < TEST_RANGE; ++cnt)
 694           {
 695             memset (db->hashtable, '\xff', nhashentries * sizeof (stridx_t));
 696
 697             max_chainlength = 0;
 698             wp = db->keystrtab;
 699
 700             twalk (db->entries, add_key);
 701
 702             if (max_chainlength == 0)
 703               {
 704                 /* No need to look further, this is as good as it gets.  */
 705                 nhashentries_best = nhashentries;
 706                 break;
 707               }
 708
 709             if (max_chainlength < chainlength_best)
 710               {
 711                 chainlength_best = max_chainlength;
 712                 nhashentries_best = nhashentries;
 713               }
 714
 715             nhashentries = next_prime (nhashentries + 1);
 716             if (nhashentries > nhashentries_max)
 717               break;
 718           }
 719
 720         /* Recompute the best table again, this time fill in the strings.  */
 721         nhashentries = nhashentries_best;
 722         memset (db->hashtable, '\xff',
 723                 2 * nhashentries_max * sizeof (stridx_t));
 724         copy_string = true;
 725         wp = db->keystrtab;
 726
 727         twalk (db->entries, add_key);
 728
 729         db->nhashentries = nhashentries_best;
 730         nhashentries_total += nhashentries_best;
 731     }
 732 }
 733
 734
 735 static int
 736 write_output (int fd)
 737 {
 738   struct nss_db_header *header;
 739   uint64_t file_offset = (sizeof (struct nss_db_header)
 740                           + (ndatabases * sizeof (header->dbs[0])));
 741   header = alloca (file_offset);
 742
 743   header->magic = NSS_DB_MAGIC;
 744   header->ndbs = ndatabases;
 745   header->valstroffset = file_offset;
 746   header->valstrlen = valstrlen;
 747
 748   size_t filled_dbs = 0;
 749   struct iovec iov[2 + ndatabases * 3];
 750   iov[0].iov_base = header;
 751   iov[0].iov_len = file_offset;
 752
 753   iov[1].iov_base = valstrtab;
 754   iov[1].iov_len = valstrlen + extrastrlen;
 755   file_offset += iov[1].iov_len;
 756
 757   size_t keydataoffset = file_offset + nhashentries_total * sizeof (stridx_t);
 758   for (struct database *db = databases; db != NULL; db = db->next)
 759     if (db->entries != NULL)
 760       {
 761         assert (file_offset % sizeof (stridx_t) == 0);
 762         assert (filled_dbs < ndatabases);
 763
 764         header->dbs[filled_dbs].id = db->dbid;
 765         memset (header->dbs[filled_dbs].pad, '\0',
 766                 sizeof (header->dbs[0].pad));
 767         header->dbs[filled_dbs].hashsize = db->nhashentries;
 768
 769         iov[2 + filled_dbs].iov_base = db->hashtable;
 770         iov[2 + filled_dbs].iov_len = db->nhashentries * sizeof (stridx_t);
 771         header->dbs[filled_dbs].hashoffset = file_offset;
 772         file_offset += iov[2 + filled_dbs].iov_len;
 773
 774         iov[2 + ndatabases + filled_dbs * 2].iov_base = db->keyidxtab;
 775         iov[2 + ndatabases + filled_dbs * 2].iov_len
 776           = db->nhashentries * sizeof (stridx_t);
 777         header->dbs[filled_dbs].keyidxoffset = keydataoffset;
 778         keydataoffset += iov[2 + ndatabases + filled_dbs * 2].iov_len;
 779
 780         iov[3 + ndatabases + filled_dbs * 2].iov_base = db->keystrtab;
 781         iov[3 + ndatabases + filled_dbs * 2].iov_len = db->keystrlen;
 782         header->dbs[filled_dbs].keystroffset = keydataoffset;
 783         keydataoffset += iov[3 + ndatabases + filled_dbs * 2].iov_len;
 784
 785         ++filled_dbs;
 786       }
 787
 788   assert (filled_dbs == ndatabases);
 789   assert (file_offset == (iov[0].iov_len + iov[1].iov_len
 790                           + nhashentries_total * sizeof (stridx_t)));
 791   header->allocate = file_offset;
 792
 793   if (writev (fd, iov, 2 + ndatabases * 3) != keydataoffset)
 794     {
 795       error (0, errno, gettext ("failed to write new database file"));
 796       return EXIT_FAILURE;
 797     }
 798
 799   return EXIT_SUCCESS;
 800 }
 801
 802
 803 static int
 804 print_database (int fd)
 805 {
 806   struct stat64 st;
 807   if (fstat64 (fd, &st) != 0)
 808     error (EXIT_FAILURE, errno, gettext ("cannot stat database file"));
 809
 810   const struct nss_db_header *header = mmap (NULL, st.st_size, PROT_READ,
 811                                              MAP_PRIVATE|MAP_POPULATE, fd, 0);
 812   if (header == MAP_FAILED)
 813     error (EXIT_FAILURE, errno, gettext ("cannot map database file"));
 814
 815   if (header->magic != NSS_DB_MAGIC)
 816     error (EXIT_FAILURE, 0, gettext ("file not a database file"));
 817
 818   const char *valstrtab = (const char *) header + header->valstroffset;
 819
 820   for (unsigned int dbidx = 0; dbidx < header->ndbs; ++dbidx)
 821     {
 822       const stridx_t *stridxtab
 823         = ((const stridx_t *) ((const char *) header
 824                                + header->dbs[dbidx].keyidxoffset));
 825       const char *keystrtab
 826         = (const char *) header + header->dbs[dbidx].keystroffset;
 827       const stridx_t *hashtab
 828         = (const stridx_t *) ((const char *) header
 829                               + header->dbs[dbidx].hashoffset);
 830
 831       for (uint32_t hidx = 0; hidx < header->dbs[dbidx].hashsize; ++hidx)
 832         if (hashtab[hidx] != ~((stridx_t) 0))
 833           printf ("%c%s %s\n",
 834                   header->dbs[dbidx].id,
 835                   keystrtab + stridxtab[hidx],
 836                   valstrtab + hashtab[hidx]);
 837     }
 838
 839   return EXIT_SUCCESS;
 840 }
 841
 842
 843 #ifdef HAVE_SELINUX
 844 static void
 845 set_file_creation_context (const char *outname, mode_t mode)
 846 {
 847   static int enabled;
 848   static int enforcing;
 849   security_context_t ctx;
 850
 851   /* Check if SELinux is enabled, and remember. */
 852   if (enabled == 0)
 853     enabled = is_selinux_enabled () ? 1 : -1;
 854   if (enabled < 0)
 855     return;
 856
 857   /* Check if SELinux is enforcing, and remember. */
 858   if (enforcing == 0)
 859     enforcing = security_getenforce () ? 1 : -1;
 860
 861   /* Determine the context which the file should have. */
 862   ctx = NULL;
 863   if (matchpathcon (outname, S_IFREG | mode, &ctx) == 0 && ctx != NULL)
 864     {
 865       if (setfscreatecon (ctx) != 0)
 866         error (enforcing > 0 ? EXIT_FAILURE : 0, 0,
 867                gettext ("cannot set file creation context for `%s'"),
 868                outname);
 869
 870       freecon (ctx);
 871     }
 872 }
 873
 874 static void
 875 reset_file_creation_context (void)
 876 {
 877   setfscreatecon (NULL);
 878 }
 879 #endif