external/ibm-public/postfix/dist/src/global/mkmap_sdbm.c

   1 /*      $NetBSD$        */
   2
   3 /*++
   4 /* NAME
   5 /*      mkmap_sdbm 3
   6 /* SUMMARY
   7 /*      create or open database, SDBM style
   8 /* SYNOPSIS
   9 /*      #include <mkmap.h>
  10 /*
  11 /*      MKMAP   *mkmap_sdbm_open(path)
  12 /*      const char *path;
  13 /* DESCRIPTION
  14 /*      This module implements support for creating SDBM databases.
  15 /*
  16 /*      mkmap_sdbm_open() takes a file name, appends the ".dir" and ".pag"
  17 /*      suffixes, and creates or opens the named SDBM database.
  18 /*      This routine is a SDBM-specific helper for the more general
  19 /*      mkmap_open() routine.
  20 /*
  21 /*      All errors are fatal.
  22 /* SEE ALSO
  23 /*      dict_sdbm(3), SDBM dictionary interface.
  24 /* LICENSE
  25 /* .ad
  26 /* .fi
  27 /*      The Secure Mailer license must be distributed with this software.
  28 /* AUTHOR(S)
  29 /*      Wietse Venema
  30 /*      IBM T.J. Watson Research
  31 /*      P.O. Box 704
  32 /*      Yorktown Heights, NY 10598, USA
  33 /*--*/
  34
  35 /* System library. */
  36
  37 #include <sys_defs.h>
  38 #include <unistd.h>
  39
  40 /* Utility library. */
  41
  42 #include <msg.h>
  43 #include <mymalloc.h>
  44 #include <stringops.h>
  45 #include <dict.h>
  46 #include <dict_sdbm.h>
  47 #include <myflock.h>
  48
  49 /* Application-specific. */
  50
  51 #include "mkmap.h"
  52
  53 #ifdef HAS_SDBM
  54
  55 #include <sdbm.h>
  56
  57 typedef struct MKMAP_SDBM {
  58     MKMAP   mkmap;                      /* parent class */
  59     char   *lock_file;                  /* path name */
  60     int     lock_fd;                    /* -1 or open locked file */
  61 } MKMAP_SDBM;
  62
  63 /* mkmap_sdbm_after_close - clean up after closing database */
  64
  65 static void mkmap_sdbm_after_close(MKMAP *mp)
  66 {
  67     MKMAP_SDBM *mkmap = (MKMAP_SDBM *) mp;
  68
  69     if (mkmap->lock_fd >= 0 && close(mkmap->lock_fd) < 0)
  70         msg_warn("close %s: %m", mkmap->lock_file);
  71     myfree(mkmap->lock_file);
  72 }
  73
  74 /* mkmap_sdbm_open - create or open database */
  75
  76 MKMAP  *mkmap_sdbm_open(const char *path)
  77 {
  78     MKMAP_SDBM *mkmap = (MKMAP_SDBM *) mymalloc(sizeof(*mkmap));
  79     char   *pag_file;
  80     int     pag_fd;
  81
  82     /*
  83      * Fill in the generic members.
  84      */
  85     mkmap->lock_file = concatenate(path, ".dir", (char *) 0);
  86     mkmap->mkmap.open = dict_sdbm_open;
  87     mkmap->mkmap.after_open = 0;
  88     mkmap->mkmap.after_close = mkmap_sdbm_after_close;
  89
  90     /*
  91      * Unfortunately, not all systems support locking on open(), so we open
  92      * the .dir and .pag files before truncating them. Keep one file open for
  93      * locking.
  94      */
  95     if ((mkmap->lock_fd = open(mkmap->lock_file, O_CREAT | O_RDWR, 0644)) < 0)
  96         msg_fatal("open %s: %m", mkmap->lock_file);
  97
  98     pag_file = concatenate(path, ".pag", (char *) 0);
  99     if ((pag_fd = open(pag_file, O_CREAT | O_RDWR, 0644)) < 0)
 100         msg_fatal("open %s: %m", pag_file);
 101     if (close(pag_fd))
 102         msg_warn("close %s: %m", pag_file);
 103     myfree(pag_file);
 104
 105     /*
 106      * Get an exclusive lock - we're going to change the database so we can't
 107      * have any spectators.
 108      */
 109     if (myflock(mkmap->lock_fd, INTERNAL_LOCK, MYFLOCK_OP_EXCLUSIVE) < 0)
 110         msg_fatal("lock %s: %m", mkmap->lock_file);
 111
 112     return (&mkmap->mkmap);
 113 }
 114
 115 #endif