nss/makedb.c

   1 /* Create simple DB database from textual input.
   2    Copyright (C) 1996-2016 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 <stdint.h>
  36 #include <sys/mman.h>
  37 #include <sys/param.h>
  38 #include <sys/stat.h>
  39 #include <sys/uio.h>
  40 #include "nss_db/nss_db.h"
  41
  42 /* Get libc version number.  */
  43 #include "../version.h"
  44
  45 /* The hashing function we use.  */
  46 #include "../intl/hash-string.h"
  47
  48 /* SELinux support.  */
  49 #ifdef HAVE_SELINUX
  50 # include <selinux/selinux.h>
  51 #endif
  52
  53 #ifndef MAP_POPULATE
  54 # define MAP_POPULATE 0
  55 #endif
  56
  57 #define PACKAGE _libc_intl_domainname
  58
  59 /* List of data bases.  */
  60 struct database
  61 {
  62   char dbid;
  63   bool extra_string;
  64   struct database *next;
  65   void *entries;
  66   size_t nentries;
  67   size_t nhashentries;
  68   stridx_t *hashtable;
  69   size_t keystrlen;
  70   stridx_t *keyidxtab;
  71   char *keystrtab;
  72 } *databases;
  73 static size_t ndatabases;
  74 static size_t nhashentries_total;
  75 static size_t valstrlen;
  76 static void *valstrtree;
  77 static char *valstrtab;
  78 static size_t extrastrlen;
  79
  80 /* Database entry.  */
  81 struct dbentry
  82 {
  83   stridx_t validx;
  84   uint32_t hashval;
  85   char str[0];
  86 };
  87
  88 /* Stored string entry.  */
  89 struct valstrentry
  90 {
  91   stridx_t idx;
  92   bool extra_string;
  93   char str[0];
  94 };
  95
  96
  97 /* True if any entry has been added.  */
  98 static bool any_dbentry;
  99
 100 /* If non-zero convert key to lower case.  */
 101 static int to_lowercase;
 102
 103 /* If non-zero print content of input file, one entry per line.  */
 104 static int do_undo;
 105
 106 /* If non-zero do not print informational messages.  */
 107 static int be_quiet;
 108
 109 /* Name of output file.  */
 110 static const char *output_name;
 111
 112 /* Name and version of program.  */
 113 static void print_version (FILE *stream, struct argp_state *state);
 114 void (*argp_program_version_hook) (FILE *, struct argp_state *) = print_version;
 115
 116 /* Definitions of arguments for argp functions.  */
 117 static const struct argp_option options[] =
 118 {
 119   { "fold-case", 'f', NULL, 0, N_("Convert key to lower case") },
 120   { "output", 'o', N_("NAME"), 0, N_("Write output to file NAME") },
 121   { "quiet", 'q', NULL, 0,
 122     N_("Do not print messages while building database") },
 123   { "undo", 'u', NULL, 0,
 124     N_("Print content of database file, one entry a line") },
 125   { "generated", 'g', N_("CHAR"), 0,
 126     N_("Generated line not part of iteration") },
 127   { NULL, 0, NULL, 0, NULL }
 128 };
 129
 130 /* Short description of program.  */
 131 static const char doc[] = N_("Create simple database from textual input.");
 132
 133 /* Strings for arguments in help texts.  */
 134 static const char args_doc[] = N_("\
 135 INPUT-FILE OUTPUT-FILE\n-o OUTPUT-FILE INPUT-FILE\n-u INPUT-FILE");
 136
 137 /* Prototype for option handler.  */
 138 static error_t parse_opt (int key, char *arg, struct argp_state *state);
 139
 140 /* Function to print some extra text in the help message.  */
 141 static char *more_help (int key, const char *text, void *input);
 142
 143 /* Data structure to communicate with argp functions.  */
 144 static struct argp argp =
 145 {
 146   options, parse_opt, args_doc, doc, NULL, more_help
 147 };
 148
 149
 150 /* List of databases which are not part of the iteration table.  */
 151 static struct db_option
 152 {
 153   char dbid;
 154   struct db_option *next;
 155 } *db_options;
 156
 157
 158 /* Prototypes for local functions.  */
 159 static int process_input (FILE *input, const char *inname,
 160                           int to_lowercase, int be_quiet);
 161 static int print_database (int fd);
 162 static void compute_tables (void);
 163 static int write_output (int fd);
 164
 165 /* SELinux support.  */
 166 #ifdef HAVE_SELINUX
 167 /* Set the SELinux file creation context for the given file. */
 168 static void set_file_creation_context (const char *outname, mode_t mode);
 169 static void reset_file_creation_context (void);
 170 #else
 171 # define set_file_creation_context(_outname,_mode)
 172 # define reset_file_creation_context()
 173 #endif
 174
 175
 176 /* External functions.  */
 177 #include <programs/xmalloc.h>
 178
 179
 180 int
 181 main (int argc, char *argv[])
 182 {
 183   const char *input_name;
 184   FILE *input_file;
 185   int remaining;
 186   int mode = 0644;
 187
 188   /* Set locale via LC_ALL.  */
 189   setlocale (LC_ALL, "");
 190
 191   /* Set the text message domain.  */
 192   textdomain (_libc_intl_domainname);
 193
 194   /* Initialize local variables.  */
 195   input_name = NULL;
 196
 197   /* Parse and process arguments.  */
 198   argp_parse (&argp, argc, argv, 0, &remaining, NULL);
 199
 200   /* Determine file names.  */
 201   if (do_undo || output_name != NULL)
 202     {
 203       if (remaining + 1 != argc)
 204         {
 205         wrong_arguments:
 206           error (0, 0, gettext ("wrong number of arguments"));
 207           argp_help (&argp, stdout, ARGP_HELP_SEE,
 208                      program_invocation_short_name);
 209           exit (1);
 210         }
 211       input_name = argv[remaining];
 212     }
 213   else
 214     {
 215       if (remaining + 2 != argc)
 216         goto wrong_arguments;
 217
 218       input_name = argv[remaining++];
 219       output_name = argv[remaining];
 220     }
 221
 222   /* Special handling if we are asked to print the database.  */
 223   if (do_undo)
 224     {
 225       int fd = open (input_name, O_RDONLY);
 226       if (fd == -1)
 227         error (EXIT_FAILURE, errno, gettext ("cannot open database file `%s'"),
 228                input_name);
 229
 230       int status = print_database (fd);
 231
 232       close (fd);
 233
 234       return status;
 235     }
 236
 237   /* Open input file.  */
 238   if (strcmp (input_name, "-") == 0 || strcmp (input_name, "/dev/stdin") == 0)
 239     input_file = stdin;
 240   else
 241     {
 242       struct stat64 st;
 243
 244       input_file = fopen64 (input_name, "r");
 245       if (input_file == NULL)
 246         error (EXIT_FAILURE, errno, gettext ("cannot open input file `%s'"),
 247                input_name);
 248
 249       /* Get the access rights from the source file.  The output file should
 250          have the same.  */
 251       if (fstat64 (fileno (input_file), &st) >= 0)
 252         mode = st.st_mode & ACCESSPERMS;
 253     }
 254
 255   /* Start the real work.  */
 256   int status = process_input (input_file, input_name, to_lowercase, be_quiet);
 257
 258   /* Close files.  */
 259   if (input_file != stdin)
 260     fclose (input_file);
 261
 262   /* No need to continue when we did not read the file successfully.  */
 263   if (status != EXIT_SUCCESS)
 264     return status;
 265
 266   /* Bail out if nothing is to be done.  */
 267   if (!any_dbentry)
 268     {
 269       if (be_quiet)
 270         return EXIT_SUCCESS;
 271       else
 272         error (EXIT_SUCCESS, 0, gettext ("no entries to be processed"));
 273     }
 274
 275   /* Compute hash and string tables.  */
 276   compute_tables ();
 277
 278   /* Open output file.  This must not be standard output so we don't
 279      handle "-" and "/dev/stdout" special.  */
 280   char *tmp_output_name;
 281   if (asprintf (&tmp_output_name, "%s.XXXXXX", output_name) == -1)
 282     error (EXIT_FAILURE, errno, gettext ("cannot create temporary file name"));
 283
 284   set_file_creation_context (output_name, mode);
 285   int fd = mkstemp (tmp_output_name);
 286   reset_file_creation_context ();
 287   if (fd == -1)
 288     error (EXIT_FAILURE, errno, gettext ("cannot create temporary file"));
 289
 290   status = write_output (fd);
 291
 292   if (status == EXIT_SUCCESS)
 293     {
 294       struct stat64 st;
 295
 296       if (fstat64 (fd, &st) == 0)
 297         {
 298           if ((st.st_mode & ACCESSPERMS) != mode)
 299             /* We ignore problems with changing the mode.  */
 300             fchmod (fd, mode);
 301         }
 302       else
 303         {
 304           error (0, errno, gettext ("cannot stat newly created file"));
 305           status = EXIT_FAILURE;
 306         }
 307     }
 308
 309   close (fd);
 310
 311   if (status == EXIT_SUCCESS)
 312     {
 313       if (rename (tmp_output_name, output_name) != 0)
 314         {
 315           error (0, errno, gettext ("cannot rename temporary file"));
 316           status = EXIT_FAILURE;
 317           goto do_unlink;
 318         }
 319     }
 320   else
 321   do_unlink:
 322     unlink (tmp_output_name);
 323
 324   return status;
 325 }
 326
 327
 328 /* Handle program arguments.  */
 329 static error_t
 330 parse_opt (int key, char *arg, struct argp_state *state)
 331 {
 332   struct db_option *newp;
 333
 334   switch (key)
 335     {
 336     case 'f':
 337       to_lowercase = 1;
 338       break;
 339     case 'o':
 340       output_name = arg;
 341       break;
 342     case 'q':
 343       be_quiet = 1;
 344       break;
 345     case 'u':
 346       do_undo = 1;
 347       break;
 348     case 'g':
 349       newp = xmalloc (sizeof (*newp));
 350       newp->dbid = arg[0];
 351       newp->next = db_options;
 352       db_options = newp;
 353       break;
 354     default:
 355       return ARGP_ERR_UNKNOWN;
 356     }
 357   return 0;
 358 }
 359
 360
 361 static char *
 362 more_help (int key, const char *text, void *input)
 363 {
 364   char *tp = NULL;
 365   switch (key)
 366     {
 367     case ARGP_KEY_HELP_EXTRA:
 368       /* We print some extra information.  */
 369       if (asprintf (&tp, gettext ("\
 370 For bug reporting instructions, please see:\n\
 371 %s.\n"), REPORT_BUGS_TO) < 0)
 372         return NULL;
 373       return tp;
 374     default:
 375       break;
 376     }
 377   return (char *) text;
 378 }
 379
 380 /* Print the version information.  */
 381 static void
 382 print_version (FILE *stream, struct argp_state *state)
 383 {
 384   fprintf (stream, "makedb %s%s\n", PKGVERSION, VERSION);
 385   fprintf (stream, gettext ("\
 386 Copyright (C) %s Free Software Foundation, Inc.\n\
 387 This is free software; see the source for copying conditions.  There is NO\n\
 388 warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n\
 389 "), "2016");
 390   fprintf (stream, gettext ("Written by %s.\n"), "Ulrich Drepper");
 391 }
 392
 393
 394 static int
 395 dbentry_compare (const void *p1, const void *p2)
 396 {
 397   const struct dbentry *d1 = (const struct dbentry *) p1;
 398   const struct dbentry *d2 = (const struct dbentry *) p2;
 399
 400   if (d1->hashval != d2->hashval)
 401     return d1->hashval < d2->hashval ? -1 : 1;
 402
 403   return strcmp (d1->str, d2->str);
 404 }
 405
 406
 407 static int
 408 valstr_compare (const void *p1, const void *p2)
 409 {
 410   const struct valstrentry *d1 = (const struct valstrentry *) p1;
 411   const struct valstrentry *d2 = (const struct valstrentry *) p2;
 412
 413   return strcmp (d1->str, d2->str);
 414 }
 415
 416
 417 static int
 418 process_input (FILE *input, const char *inname, int to_lowercase, int be_quiet)
 419 {
 420   char *line;
 421   size_t linelen;
 422   int status;
 423   size_t linenr;
 424
 425   line = NULL;
 426   linelen = 0;
 427   status = EXIT_SUCCESS;
 428   linenr = 0;
 429
 430   struct database *last_database = NULL;
 431
 432   while (!feof_unlocked (input))
 433     {
 434       ssize_t n = getline (&line, &linelen, input);
 435       if (n < 0)
 436         /* This means end of file or some bug.  */
 437         break;
 438       if (n == 0)
 439         /* Short read.  Probably interrupted system call. */
 440         continue;
 441
 442       ++linenr;
 443
 444       if (line[n - 1] == '\n')
 445         /* Remove trailing newline.  */
 446         line[--n] = '\0';
 447
 448       char *cp = line;
 449       while (isspace (*cp))
 450         ++cp;
 451
 452       if (*cp == '#' || *cp == '\0')
 453         /* First non-space character in line '#': it's a comment.
 454            Also go to the next line if it is empty except for whitespaces. */
 455         continue;
 456
 457       /* Skip over the character indicating the database so that it is not
 458          affected by TO_LOWERCASE.  */
 459       char *key = cp++;
 460       while (*cp != '\0' && !isspace (*cp))
 461         {
 462           if (to_lowercase)
 463             *cp = tolower (*cp);
 464           ++cp;
 465         }
 466
 467       if (*cp == '\0')
 468         /* It's a line without a value field.  */
 469         continue;
 470
 471       *cp++ = '\0';
 472       size_t keylen = cp - key;
 473
 474       while (isspace (*cp))
 475         ++cp;
 476
 477       char *data = cp;
 478       size_t datalen = (&line[n] - cp) + 1;
 479
 480       /* Find the database.  */
 481       if (last_database == NULL || last_database->dbid != key[0])
 482         {
 483           last_database = databases;
 484           while (last_database != NULL && last_database->dbid != key[0])
 485             last_database = last_database->next;
 486
 487           if (last_database == NULL)
 488             {
 489               last_database = xmalloc (sizeof (*last_database));
 490               last_database->dbid = key[0];
 491               last_database->extra_string = false;
 492               last_database->next = databases;
 493               last_database->entries = NULL;
 494               last_database->nentries = 0;
 495               last_database->keystrlen = 0;
 496               databases = last_database;
 497
 498               struct db_option *runp = db_options;
 499               while (runp != NULL)
 500                 if (runp->dbid == key[0])
 501                   {
 502                     last_database->extra_string = true;
 503                     break;
 504                   }
 505                 else
 506                   runp = runp->next;
 507             }
 508         }
 509
 510       /* Skip the database selector.  */
 511       ++key;
 512       --keylen;
 513
 514       /* Store the data.  */
 515       struct valstrentry *nentry = xmalloc (sizeof (struct valstrentry)
 516                                             + datalen);
 517       if (last_database->extra_string)
 518         nentry->idx = extrastrlen;
 519       else
 520         nentry->idx = valstrlen;
 521       nentry->extra_string = last_database->extra_string;
 522       memcpy (nentry->str, data, datalen);
 523
 524       struct valstrentry **fdata = tsearch (nentry, &valstrtree,
 525                                             valstr_compare);
 526       if (fdata == NULL)
 527         error (EXIT_FAILURE, errno, gettext ("cannot create search tree"));
 528
 529       if (*fdata != nentry)
 530         {
 531           /* We can reuse a string.  */
 532           free (nentry);
 533           nentry = *fdata;
 534         }
 535       else
 536         if (last_database->extra_string)
 537           extrastrlen += datalen;
 538         else
 539           valstrlen += datalen;
 540
 541       /* Store the key.  */
 542       struct dbentry *newp = xmalloc (sizeof (struct dbentry) + keylen);
 543       newp->validx = nentry->idx;
 544       newp->hashval = __hash_string (key);
 545       memcpy (newp->str, key, keylen);
 546
 547       struct dbentry **found = tsearch (newp, &last_database->entries,
 548                                         dbentry_compare);
 549       if (found == NULL)
 550         error (EXIT_FAILURE, errno, gettext ("cannot create search tree"));
 551
 552       if (*found != newp)
 553         {
 554           free (newp);
 555           if (!be_quiet)
 556             error_at_line (0, 0, inname, linenr, gettext ("duplicate key"));
 557           continue;
 558         }
 559
 560       ++last_database->nentries;
 561       last_database->keystrlen += keylen;
 562
 563       any_dbentry = true;
 564     }
 565
 566   if (ferror_unlocked (input))
 567     {
 568       error (0, 0, gettext ("problems while reading `%s'"), inname);
 569       status = EXIT_FAILURE;
 570     }
 571
 572   return status;
 573 }
 574
 575
 576 static void
 577 copy_valstr (const void *nodep, const VISIT which, const int depth)
 578 {
 579   if (which != leaf && which != postorder)
 580     return;
 581
 582   const struct valstrentry *p = *(const struct valstrentry **) nodep;
 583
 584   strcpy (valstrtab + (p->extra_string ? valstrlen : 0) + p->idx, p->str);
 585 }
 586
 587
 588 /* Determine if the candidate is prime by using a modified trial division
 589    algorithm. The candidate must be both odd and greater than 4.  */
 590 static int
 591 is_prime (size_t candidate)
 592 {
 593   size_t divn = 3;
 594   size_t sq = divn * divn;
 595
 596   assert (candidate > 4 && candidate % 2 != 0);
 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 sure that we're always greater than 4.  */
 613   seed = (seed + 4) | 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