nss/makedb.c

   1 /* Create simple DB database from textual input.
   2    Copyright (C) 1996-2000, 2011 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, write to the Free
  18    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  19    02111-1307 USA.  */
  20
  21 #include <argp.h>
  22 #include <assert.h>
  23 #include <ctype.h>
  24 #include <errno.h>
  25 #include <error.h>
  26 #include <fcntl.h>
  27 #include <inttypes.h>
  28 #include <libintl.h>
  29 #include <locale.h>
  30 #include <search.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/stat.h>
  37 #include "nss_db/nss_db.h"
  38
  39 /* Get libc version number.  */
  40 #include "../version.h"
  41
  42 /* The hashing function we use.  */
  43 #include "../intl/hash-string.h"
  44
  45 /* SELinux support.  */
  46 #ifdef HAVE_SELINUX
  47 # include <selinux/selinux.h>
  48 #endif
  49
  50 #define PACKAGE _libc_intl_domainname
  51
  52 /* List of data bases.  */
  53 struct database
  54 {
  55   char dbid;
  56   bool extra_string;
  57   struct database *next;
  58   void *entries;
  59   size_t nentries;
  60   size_t nhashentries;
  61   stridx_t *hashtable;
  62   size_t keystrlen;
  63   stridx_t *keyidxtab;
  64   char *keystrtab;
  65 } *databases;
  66 static size_t ndatabases;
  67 static size_t nhashentries_total;
  68 static size_t valstrlen;
  69 static void *valstrtree;
  70 static char *valstrtab;
  71 static size_t extrastrlen;
  72
  73 /* Database entry.  */
  74 struct dbentry
  75 {
  76   stridx_t validx;
  77   uint32_t hashval;
  78   char str[0];
  79 };
  80
  81 /* Stored string entry.  */
  82 struct valstrentry
  83 {
  84   stridx_t idx;
  85   bool extra_string;
  86   char str[0];
  87 };
  88
  89
  90 /* True if any entry has been added.  */
  91 static bool any_dbentry;
  92
  93 /* If non-zero convert key to lower case.  */
  94 static int to_lowercase;
  95
  96 /* If non-zero print content of input file, one entry per line.  */
  97 static int do_undo;
  98
  99 /* If non-zero do not print informational messages.  */
 100 static int be_quiet;
 101
 102 /* Name of output file.  */
 103 static const char *output_name;
 104
 105 /* Name and version of program.  */
 106 static void print_version (FILE *stream, struct argp_state *state);
 107 void (*argp_program_version_hook) (FILE *, struct argp_state *) = print_version;
 108
 109 /* Definitions of arguments for argp functions.  */
 110 static const struct argp_option options[] =
 111 {
 112   { "fold-case", 'f', NULL, 0, N_("Convert key to lower case") },
 113   { "output", 'o', N_("NAME"), 0, N_("Write output to file NAME") },
 114   { "quiet", 'q', NULL, 0,
 115     N_("Do not print messages while building database") },
 116   { "undo", 'u', NULL, 0,
 117     N_("Print content of database file, one entry a line") },
 118   { "generated", 'g', N_("CHAR"), 0,
 119     N_("Generated line not part of iteration") },
 120   { NULL, 0, NULL, 0, NULL }
 121 };
 122
 123 /* Short description of program.  */
 124 static const char doc[] = N_("Create simple database from textual input.");
 125
 126 /* Strings for arguments in help texts.  */
 127 static const char args_doc[] = N_("\
 128 INPUT-FILE OUTPUT-FILE\n-o OUTPUT-FILE INPUT-FILE\n-u INPUT-FILE");
 129
 130 /* Prototype for option handler.  */
 131 static error_t parse_opt (int key, char *arg, struct argp_state *state);
 132
 133 /* Function to print some extra text in the help message.  */
 134 static char *more_help (int key, const char *text, void *input);
 135
 136 /* Data structure to communicate with argp functions.  */
 137 static struct argp argp =
 138 {
 139   options, parse_opt, args_doc, doc, NULL, more_help
 140 };
 141
 142
 143 /* List of databases which are not part of the iteration table.  */
 144 static struct db_option
 145 {
 146   char dbid;
 147   struct db_option *next;
 148 } *db_options;
 149
 150
 151 /* Prototypes for local functions.  */
 152 static int process_input (FILE *input, const char *inname,
 153                           int to_lowercase, int be_quiet);
 154 static int print_database (int fd);
 155 static void compute_tables (void);
 156 static int write_output (int fd);
 157
 158 /* SELinux support.  */
 159 #ifdef HAVE_SELINUX
 160 /* Set the SELinux file creation context for the given file. */
 161 static void set_file_creation_context (const char *outname, mode_t mode);
 162 static void reset_file_creation_context (void);
 163 #else
 164 # define set_file_creation_context(_outname,_mode)
 165 # define reset_file_creation_context()
 166 #endif
 167
 168
 169 /* External functions.  */
 170 extern void *xmalloc (size_t n) __attribute_malloc__;
 171 extern void *xcalloc (size_t n, size_t m) __attribute_malloc__;
 172
 173
 174 int
 175 main (int argc, char *argv[])
 176 {
 177   const char *input_name;
 178   FILE *input_file;
 179   int remaining;
 180   int mode = 0644;
 181
 182   /* Set locale via LC_ALL.  */
 183   setlocale (LC_ALL, "");
 184
 185   /* Set the text message domain.  */
 186   textdomain (_libc_intl_domainname);
 187
 188   /* Initialize local variables.  */
 189   input_name = NULL;
 190
 191   /* Parse and process arguments.  */
 192   argp_parse (&argp, argc, argv, 0, &remaining, NULL);
 193
 194   /* Determine file names.  */
 195   if (do_undo || output_name != NULL)
 196     {
 197       if (remaining + 1 != argc)
 198         {
 199         wrong_arguments:
 200           error (0, 0, gettext ("wrong number of arguments"));
 201           argp_help (&argp, stdout, ARGP_HELP_SEE,
 202                      program_invocation_short_name);
 203           exit (1);
 204         }
 205       input_name = argv[remaining];
 206     }
 207   else
 208     {
 209       if (remaining + 2 != argc)
 210         goto wrong_arguments;
 211
 212       input_name = argv[remaining++];
 213       output_name = argv[remaining];
 214     }
 215
 216   /* Special handling if we are asked to print the database.  */
 217   if (do_undo)
 218     {
 219       int fd = open (input_name, O_RDONLY);
 220       if (fd == -1)
 221         error (EXIT_FAILURE, errno, gettext ("cannot open database file `%s'"),
 222                input_name);
 223
 224       int status = print_database (fd);
 225
 226       close (fd);
 227
 228       return status;
 229     }
 230
 231   /* Open input file.  */
 232   if (strcmp (input_name, "-") == 0 || strcmp (input_name, "/dev/stdin") == 0)
 233     input_file = stdin;
 234   else
 235     {
 236       struct stat64 st;
 237
 238       input_file = fopen64 (input_name, "r");
 239       if (input_file == NULL)
 240         error (EXIT_FAILURE, errno, gettext ("cannot open input file `%s'"),
 241                input_name);
 242
 243       /* Get the access rights from the source file.  The output file should
 244          have the same.  */
 245       if (fstat64 (fileno (input_file), &st) >= 0)
 246         mode = st.st_mode & ACCESSPERMS;
 247     }
 248
 249   /* Start the real work.  */
 250   int status = process_input (input_file, input_name, to_lowercase, be_quiet);
 251
 252   /* Close files.  */
 253   if (input_file != stdin)
 254     fclose (input_file);
 255
 256   /* No need to continue when we did not read the file successfully.  */
 257   if (status != EXIT_SUCCESS)
 258     return status;
 259
 260   /* Bail out if nothing is to be done.  */
 261   if (!any_dbentry)
 262     {
 263       if (be_quiet)
 264         return EXIT_SUCCESS;
 265       else
 266         error (EXIT_SUCCESS, 0, gettext ("no entries to be processed"));
 267     }
 268
 269   /* Compute hash and string tables.  */
 270   compute_tables ();
 271
 272   /* Open output file.  This must not be standard output so we don't
 273      handle "-" and "/dev/stdout" special.  */
 274   char *tmp_output_name;
 275   if (asprintf (&tmp_output_name, "%s.XXXXXX", output_name) == -1)
 276     error (EXIT_FAILURE, errno, gettext ("cannot create temporary file name"));
 277
 278   set_file_creation_context (output_name, mode);
 279   int fd = mkstemp (tmp_output_name);
 280   reset_file_creation_context ();
 281   if (fd == -1)
 282     error (EXIT_FAILURE, errno, gettext ("cannot create temporary file"));
 283
 284   status = write_output (fd);
 285
 286   if (status == EXIT_SUCCESS)
 287     {
 288       struct stat64 st;
 289
 290       if (fstat64 (fd, &st) == 0)
 291         {
 292           if ((st.st_mode & ACCESSPERMS) != mode)
 293             /* We ignore problems with changing the mode.  */
 294             fchmod (fd, mode);
 295         }
 296       else
 297         {
 298           error (0, errno, gettext ("cannot stat newly created file"));
 299           status = EXIT_FAILURE;
 300         }
 301     }
 302
 303   close (fd);
 304
 305   if (status == EXIT_SUCCESS)
 306     {
 307       if (rename (tmp_output_name, output_name) != 0)
 308         {
 309           error (0, errno, gettext ("cannot rename temporary file"));
 310           status = EXIT_FAILURE;
 311           goto do_unlink;
 312         }
 313     }
 314   else
 315   do_unlink:
 316     unlink (tmp_output_name);
 317
 318   return status;
 319 }
 320
 321
 322 /* Handle program arguments.  */
 323 static error_t
 324 parse_opt (int key, char *arg, struct argp_state *state)
 325 {
 326   struct db_option *newp;
 327
 328   switch (key)
 329     {
 330     case 'f':
 331       to_lowercase = 1;
 332       break;
 333     case 'o':
 334       output_name = arg;
 335       break;
 336     case 'q':
 337       be_quiet = 1;
 338       break;
 339     case 'u':
 340       do_undo = 1;
 341       break;
 342     case 'g':
 343       newp = xmalloc (sizeof (*newp));
 344       newp->dbid = arg[0];
 345       newp->next = db_options;
 346       db_options = newp;
 347       break;
 348     default:
 349       return ARGP_ERR_UNKNOWN;
 350     }
 351   return 0;
 352 }
 353
 354
 355 static char *
 356 more_help (int key, const char *text, void *input)
 357 {
 358   switch (key)
 359     {
 360     case ARGP_KEY_HELP_EXTRA:
 361       /* We print some extra information.  */
 362       return strdup (gettext ("\
 363 For bug reporting instructions, please see:\n\
 364 <http://www.gnu.org/software/libc/bugs.html>.\n"));
 365     default:
 366       break;
 367     }
 368   return (char *) text;
 369 }
 370
 371 /* Print the version information.  */
 372 static void
 373 print_version (FILE *stream, struct argp_state *state)
 374 {
 375   fprintf (stream, "makedb (GNU %s) %s\n", PACKAGE, VERSION);
 376   fprintf (stream, gettext ("\
 377 Copyright (C) %s Free Software Foundation, Inc.\n\
 378 This is free software; see the source for copying conditions.  There is NO\n\
 379 warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n\
 380 "), "2011");
 381   fprintf (stream, gettext ("Written by %s.\n"), "Ulrich Drepper");
 382 }
 383
 384
 385 static int
 386 dbentry_compare (const void *p1, const void *p2)
 387 {
 388   const struct dbentry *d1 = (const struct dbentry *) p1;
 389   const struct dbentry *d2 = (const struct dbentry *) p2;
 390
 391   if (d1->hashval != d2->hashval)
 392     return d1->hashval < d2->hashval ? -1 : 1;
 393
 394   return strcmp (d1->str, d2->str);
 395 }
 396
 397
 398 static int
 399 valstr_compare (const void *p1, const void *p2)
 400 {
 401   const struct valstrentry *d1 = (const struct valstrentry *) p1;
 402   const struct valstrentry *d2 = (const struct valstrentry *) p2;
 403
 404   return strcmp (d1->str, d2->str);
 405 }
 406
 407
 408 static int
 409 process_input (input, inname, to_lowercase, be_quiet)
 410      FILE *input;
 411      const char *inname;
 412      int to_lowercase;
 413      int be_quiet;
 414 {
 415   char *line;
 416   size_t linelen;
 417   int status;
 418   size_t linenr;
 419
 420   line = NULL;
 421   linelen = 0;
 422   status = EXIT_SUCCESS;
 423   linenr = 0;
 424
 425   struct database *last_database = NULL;
 426
 427   while (!feof_unlocked (input))
 428     {
 429       ssize_t n = getline (&line, &linelen, input);
 430       if (n < 0)
 431         /* This means end of file or some bug.  */
 432         break;
 433       if (n == 0)
 434         /* Short read.  Probably interrupted system call. */
 435         continue;
 436
 437       ++linenr;
 438
 439       if (line[n - 1] == '\n')
 440         /* Remove trailing newline.  */
 441         line[--n] = '\0';
 442
 443       char *cp = line;
 444       while (isspace (*cp))
 445         ++cp;
 446
 447       if (*cp == '#' || *cp == '\0')
 448         /* First non-space character in line '#': it's a comment.
 449            Also go to the next line if it is empty except for whitespaces. */
 450         continue;
 451
 452       /* Skip over the character indicating the database so that it is not
 453          affected by TO_LOWERCASE.  */
 454       char *key = cp++;
 455       while (*cp != '\0' && !isspace (*cp))
 456         {
 457           if (to_lowercase)
 458             *cp = tolower (*cp);
 459           ++cp;
 460         }
 461
 462       if (*cp == '\0')
 463         /* It's a line without a value field.  */
 464         continue;
 465
 466       *cp++ = '\0';
 467       size_t keylen = cp - key;
 468
 469       while (isspace (*cp))
 470         ++cp;
 471
 472       char *data = cp;
 473       size_t datalen = (&line[n] - cp) + 1;
 474
 475       /* Find the database.  */
 476       if (last_database == NULL || last_database->dbid != key[0])
 477         {
 478           last_database = databases;
 479           while (last_database != NULL && last_database->dbid != key[0])
 480             last_database = last_database->next;
 481
 482           if (last_database == NULL)
 483             {
 484               last_database = xmalloc (sizeof (*last_database));
 485               last_database->dbid = key[0];
 486               last_database->extra_string = false;
 487               last_database->next = databases;
 488               last_database->entries = NULL;
 489               last_database->nentries = 0;
 490               last_database->keystrlen = 0;
 491               databases = last_database;
 492
 493               struct db_option *runp = db_options;
 494               while (runp != NULL)
 495                 if (runp->dbid == key[0])
 496                   {
 497                     last_database->extra_string = true;
 498                     break;
 499                   }
 500                 else
 501                   runp = runp->next;
 502             }
 503         }
 504
 505       /* Skip the database selector.  */
 506       ++key;
 507       --keylen;
 508
 509       /* Store the data.  */
 510       struct valstrentry *nentry = xmalloc (sizeof (struct valstrentry)
 511                                             + datalen);
 512       if (last_database->extra_string)
 513         nentry->idx = extrastrlen;
 514       else
 515         nentry->idx = valstrlen;
 516       nentry->extra_string = last_database->extra_string;
 517       memcpy (nentry->str, data, datalen);
 518
 519       struct valstrentry **fdata = tsearch (nentry, &valstrtree,
 520                                             valstr_compare);
 521       if (fdata == NULL)
 522         error (EXIT_FAILURE, errno, gettext ("cannot create search tree"));
 523
 524       if (*fdata != nentry)
 525         {
 526           /* We can reuse a string.  */
 527           free (nentry);
 528           nentry = *fdata;
 529         }
 530       else
 531         if (last_database->extra_string)
 532           extrastrlen += datalen;
 533         else
 534           valstrlen += datalen;
 535
 536       /* Store the key.  */
 537       struct dbentry *newp = xmalloc (sizeof (struct dbentry) + keylen);
 538       newp->validx = nentry->idx;
 539       newp->hashval = __hash_string (key);
 540       memcpy (newp->str, key, keylen);
 541
 542       struct dbentry **found = tsearch (newp, &last_database->entries,
 543                                         dbentry_compare);
 544       if (found == NULL)
 545         error (EXIT_FAILURE, errno, gettext ("cannot create search tree"));
 546
 547       if (*found != newp)
 548         {
 549           free (newp);
 550           if (!be_quiet)
 551             error_at_line (0, 0, inname, linenr, gettext ("duplicate key"));
 552           continue;
 553         }
 554
 555       ++last_database->nentries;
 556       last_database->keystrlen += keylen;
 557
 558       any_dbentry = true;
 559     }
 560
 561   if (ferror_unlocked (input))
 562     {
 563       error (0, 0, gettext ("problems while reading `%s'"), inname);
 564       status = EXIT_FAILURE;
 565     }
 566
 567   return status;
 568 }
 569
 570
 571 static void
 572 copy_valstr (const void *nodep, const VISIT which, const int depth)
 573 {
 574   if (which != leaf && which != postorder)
 575     return;
 576
 577   const struct valstrentry *p = *(const struct valstrentry **) nodep;
 578
 579   strcpy (valstrtab + (p->extra_string ? valstrlen : 0) + p->idx, p->str);
 580 }
 581
 582
 583 static int
 584 is_prime (size_t candidate)
 585 {
 586   /* No even number and none less than 10 will be passed here.  */
 587   size_t divn = 3;
 588   size_t sq = divn * divn;
 589
 590   while (sq < candidate && candidate % divn != 0)
 591     {
 592       ++divn;
 593       sq += 4 * divn;
 594       ++divn;
 595     }
 596
 597   return candidate % divn != 0;
 598 }
 599
 600
 601 static size_t
 602 next_prime (size_t seed)
 603 {
 604   /* Make it definitely odd.  */
 605   seed |= 1;
 606
 607   while (!is_prime (seed))
 608     seed += 2;
 609
 610   return seed;
 611 }
 612
 613
 614 static void
 615 compute_tables (void)
 616 {
 617   valstrtab = xmalloc (roundup (valstrlen + extrastrlen, sizeof (stridx_t)));
 618   while ((valstrlen + extrastrlen) % sizeof (stridx_t) != 0)
 619     valstrtab[valstrlen++] = '\0';
 620   twalk (valstrtree, copy_valstr);
 621
 622   static struct database *db;
 623   for (db = databases; db != NULL; db = db->next)
 624     if (db->nentries != 0)
 625       {
 626         ++ndatabases;
 627
 628         /* We simply use an odd number large than twice the number of
 629            elements to store in the hash table for the size.  This gives
 630            enough efficiency.  */
 631 #define TEST_RANGE 30
 632         size_t nhashentries_min = next_prime (db->nentries < TEST_RANGE
 633                                               ? db->nentries
 634                                               : db->nentries * 2 - TEST_RANGE);
 635         size_t nhashentries_max = MAX (nhashentries_min, db->nentries * 4);
 636         size_t nhashentries_best = nhashentries_min;
 637         size_t chainlength_best = db->nentries;
 638
 639         db->hashtable = xmalloc (2 * nhashentries_max * sizeof (stridx_t)
 640                                  + db->keystrlen);
 641         db->keyidxtab = db->hashtable + nhashentries_max;
 642         db->keystrtab = (char *) (db->keyidxtab + nhashentries_max);
 643
 644         static size_t max_chainlength;
 645         static char *wp;
 646         static size_t nhashentries;
 647         static bool copy_string;
 648
 649         void add_key(const void *nodep, const VISIT which, const int depth)
 650         {
 651           if (which != leaf && which != postorder)
 652             return;
 653
 654           const struct dbentry *dbe = *(const struct dbentry **) nodep;
 655
 656           ptrdiff_t stridx;
 657           if (copy_string)
 658             {
 659               stridx = wp - db->keystrtab;
 660               wp = stpcpy (wp, dbe->str) + 1;
 661             }
 662           else
 663             stridx = 0;
 664
 665           size_t hidx = dbe->hashval % nhashentries;
 666           size_t hval2 = 1 + dbe->hashval % (nhashentries - 2);
 667           size_t chainlength = 0;
 668
 669           while (db->hashtable[hidx] != ~((stridx_t) 0))
 670             {
 671               ++chainlength;
 672               if ((hidx += hval2) >= nhashentries)
 673                 hidx -= nhashentries;
 674             }
 675
 676           db->hashtable[hidx] = ((db->extra_string ? valstrlen : 0)
 677                                  + dbe->validx);
 678           db->keyidxtab[hidx] = stridx;
 679
 680           max_chainlength = MAX (max_chainlength, chainlength);
 681         }
 682
 683         copy_string = false;
 684         nhashentries = nhashentries_min;
 685         for (size_t cnt = 0; cnt < TEST_RANGE; ++cnt)
 686           {
 687             memset (db->hashtable, '\xff', nhashentries * sizeof (stridx_t));
 688
 689             max_chainlength = 0;
 690             wp = db->keystrtab;
 691
 692             twalk (db->entries, add_key);
 693
 694             if (max_chainlength == 0)
 695               {
 696                 /* No need to look further, this is as good as it gets.  */
 697                 nhashentries_best = nhashentries;
 698                 break;
 699               }
 700
 701             if (max_chainlength < chainlength_best)
 702               {
 703                 chainlength_best = max_chainlength;
 704                 nhashentries_best = nhashentries;
 705               }
 706
 707             nhashentries = next_prime (nhashentries + 1);
 708             if (nhashentries > nhashentries_max)
 709               break;
 710           }
 711
 712         /* Recompute the best table again, this time fill in the strings.  */
 713         nhashentries = nhashentries_best;
 714         memset (db->hashtable, '\xff',
 715                 2 * nhashentries_max * sizeof (stridx_t));
 716         copy_string = true;
 717         wp = db->keystrtab;
 718
 719         twalk (db->entries, add_key);
 720
 721         db->nhashentries = nhashentries_best;
 722         nhashentries_total += nhashentries_best;
 723     }
 724 }
 725
 726
 727 static int
 728 write_output (int fd)
 729 {
 730   struct nss_db_header *header;
 731   uint64_t file_offset = (sizeof (struct nss_db_header)
 732                           + (ndatabases * sizeof (header->dbs[0])));
 733   header = alloca (file_offset);
 734
 735   header->magic = NSS_DB_MAGIC;
 736   header->ndbs = ndatabases;
 737   header->valstroffset = file_offset;
 738   header->valstrlen = valstrlen;
 739
 740   size_t filled_dbs = 0;
 741   struct iovec iov[2 + ndatabases * 3];
 742   iov[0].iov_base = header;
 743   iov[0].iov_len = file_offset;
 744
 745   iov[1].iov_base = valstrtab;
 746   iov[1].iov_len = valstrlen + extrastrlen;
 747   file_offset += iov[1].iov_len;
 748
 749   size_t keydataoffset = file_offset + nhashentries_total * sizeof (stridx_t);
 750   for (struct database *db = databases; db != NULL; db = db->next)
 751     if (db->entries != NULL)
 752       {
 753         assert (file_offset % sizeof (stridx_t) == 0);
 754         assert (filled_dbs < ndatabases);
 755
 756         header->dbs[filled_dbs].id = db->dbid;
 757         memset (header->dbs[filled_dbs].pad, '\0',
 758                 sizeof (header->dbs[0].pad));
 759         header->dbs[filled_dbs].hashsize = db->nhashentries;
 760
 761         iov[2 + filled_dbs].iov_base = db->hashtable;
 762         iov[2 + filled_dbs].iov_len = db->nhashentries * sizeof (stridx_t);
 763         header->dbs[filled_dbs].hashoffset = file_offset;
 764         file_offset += iov[2 + filled_dbs].iov_len;
 765
 766         iov[2 + ndatabases + filled_dbs * 2].iov_base = db->keyidxtab;
 767         iov[2 + ndatabases + filled_dbs * 2].iov_len
 768           = db->nhashentries * sizeof (stridx_t);
 769         header->dbs[filled_dbs].keyidxoffset = keydataoffset;
 770         keydataoffset += iov[2 + ndatabases + filled_dbs * 2].iov_len;
 771
 772         iov[3 + ndatabases + filled_dbs * 2].iov_base = db->keystrtab;
 773         iov[3 + ndatabases + filled_dbs * 2].iov_len = db->keystrlen;
 774         header->dbs[filled_dbs].keystroffset = keydataoffset;
 775         keydataoffset += iov[3 + ndatabases + filled_dbs * 2].iov_len;
 776
 777         ++filled_dbs;
 778       }
 779
 780   assert (filled_dbs == ndatabases);
 781   assert (file_offset == (iov[0].iov_len + iov[1].iov_len
 782                           + nhashentries_total * sizeof (stridx_t)));
 783   header->allocate = file_offset;
 784
 785   if (writev (fd, iov, 2 + ndatabases * 3) != keydataoffset)
 786     {
 787       error (0, errno, gettext ("failed to write new database file"));
 788       return EXIT_FAILURE;
 789     }
 790
 791   return EXIT_SUCCESS;
 792 }
 793
 794
 795 static int
 796 print_database (int fd)
 797 {
 798   struct stat64 st;
 799   if (fstat64 (fd, &st) != 0)
 800     error (EXIT_FAILURE, errno, gettext ("cannot stat database file"));
 801
 802   const struct nss_db_header *header = mmap (NULL, st.st_size, PROT_READ,
 803                                              MAP_PRIVATE|MAP_POPULATE, fd, 0);
 804   if (header == MAP_FAILED)
 805     error (EXIT_FAILURE, errno, gettext ("cannot map database file"));
 806
 807   if (header->magic != NSS_DB_MAGIC)
 808     error (EXIT_FAILURE, 0, gettext ("file not a database file"));
 809
 810   const char *valstrtab = (const char *) header + header->valstroffset;
 811
 812   for (unsigned int dbidx = 0; dbidx < header->ndbs; ++dbidx)
 813     {
 814       const stridx_t *stridxtab
 815         = ((const stridx_t *) ((const char *) header
 816                                + header->dbs[dbidx].keyidxoffset));
 817       const char *keystrtab
 818         = (const char *) header + header->dbs[dbidx].keystroffset;
 819       const stridx_t *hashtab
 820         = (const stridx_t *) ((const char *) header
 821                               + header->dbs[dbidx].hashoffset);
 822
 823       for (uint32_t hidx = 0; hidx < header->dbs[dbidx].hashsize; ++hidx)
 824         if (hashtab[hidx] != ~((stridx_t) 0))
 825           printf ("%c%s %s\n",
 826                   header->dbs[dbidx].id,
 827                   keystrtab + stridxtab[hidx],
 828                   valstrtab + hashtab[hidx]);
 829     }
 830
 831   return EXIT_SUCCESS;
 832 }
 833
 834
 835 #ifdef HAVE_SELINUX
 836 static void
 837 set_file_creation_context (const char *outname, mode_t mode)
 838 {
 839   static int enabled;
 840   static int enforcing;
 841   security_context_t ctx;
 842
 843   /* Check if SELinux is enabled, and remember. */
 844   if (enabled == 0)
 845     enabled = is_selinux_enabled ();
 846   if (enabled < 0)
 847     return;
 848
 849   /* Check if SELinux is enforcing, and remember. */
 850   if (enforcing == 0)
 851     enforcing = security_getenforce () ? 1 : -1;
 852
 853   /* Determine the context which the file should have. */
 854   ctx = NULL;
 855   if (matchpathcon (outname, S_IFREG | mode, &ctx) == 0 && ctx != NULL)
 856     {
 857       if (setfscreatecon (ctx) != 0)
 858         error (enforcing > 0 ? EXIT_FAILURE : 0, 0,
 859                gettext ("cannot set file creation context for `%s'"),
 860                outname);
 861
 862       freecon (ctx);
 863     }
 864 }
 865
 866 static void
 867 reset_file_creation_context (void)
 868 {
 869   setfscreatecon (NULL);
 870 }
 871 #endif