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

   1 /*      $NetBSD$        */
   2
   3 /*++
   4 /* NAME
   5 /*      mkmap_dbm 3
   6 /* SUMMARY
   7 /*      create or open database, DBM style
   8 /* SYNOPSIS
   9 /*      #include <mkmap.h>
  10 /*
  11 /*      MKMAP   *mkmap_dbm_open(path)
  12 /*      const char *path;
  13 /* DESCRIPTION
  14 /*      This module implements support for creating DBM databases.
  15 /*
  16 /*      mkmap_dbm_open() takes a file name, appends the ".dir" and ".pag"
  17 /*      suffixes, and creates or opens the named DBM database.
  18 /*      This routine is a DBM-specific helper for the more general
  19 /*      mkmap_open() routine.
  20 /*
  21 /*      All errors are fatal.
  22 /* SEE ALSO
  23 /*      dict_dbm(3), DBM 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_dbm.h>
  47 #include <myflock.h>
  48
  49 /* Application-specific. */
  50
  51 #include "mkmap.h"
  52
  53 #ifdef HAS_DBM
  54 #ifdef PATH_NDBM_H
  55 #include PATH_NDBM_H
  56 #else
  57 #include <ndbm.h>
  58 #endif
  59
  60 typedef struct MKMAP_DBM {
  61     MKMAP   mkmap;                      /* parent class */
  62     char   *lock_file;                  /* path name */
  63     int     lock_fd;                    /* -1 or open locked file */
  64 } MKMAP_DBM;
  65
  66 /* mkmap_dbm_after_close - clean up after closing database */
  67
  68 static void mkmap_dbm_after_close(MKMAP *mp)
  69 {
  70     MKMAP_DBM *mkmap = (MKMAP_DBM *) mp;
  71
  72     if (mkmap->lock_fd >= 0 && close(mkmap->lock_fd) < 0)
  73         msg_warn("close %s: %m", mkmap->lock_file);
  74     myfree(mkmap->lock_file);
  75 }
  76
  77 /* mkmap_dbm_open - create or open database */
  78
  79 MKMAP  *mkmap_dbm_open(const char *path)
  80 {
  81     MKMAP_DBM *mkmap = (MKMAP_DBM *) mymalloc(sizeof(*mkmap));
  82     char   *pag_file;
  83     int     pag_fd;
  84
  85     /*
  86      * Fill in the generic members.
  87      */
  88     mkmap->lock_file = concatenate(path, ".dir", (char *) 0);
  89     mkmap->mkmap.open = dict_dbm_open;
  90     mkmap->mkmap.after_open = 0;
  91     mkmap->mkmap.after_close = mkmap_dbm_after_close;
  92
  93     /*
  94      * Unfortunately, not all systems support locking on open(), so we open
  95      * the .dir and .pag files before truncating them. Keep one file open for
  96      * locking.
  97      */
  98     if ((mkmap->lock_fd = open(mkmap->lock_file, O_CREAT | O_RDWR, 0644)) < 0)
  99         msg_fatal("open %s: %m", mkmap->lock_file);
 100
 101     pag_file = concatenate(path, ".pag", (char *) 0);
 102     if ((pag_fd = open(pag_file, O_CREAT | O_RDWR, 0644)) < 0)
 103         msg_fatal("open %s: %m", pag_file);
 104     if (close(pag_fd))
 105         msg_warn("close %s: %m", pag_file);
 106     myfree(pag_file);
 107
 108     /*
 109      * Get an exclusive lock - we're going to change the database so we can't
 110      * have any spectators.
 111      */
 112     if (myflock(mkmap->lock_fd, INTERNAL_LOCK, MYFLOCK_OP_EXCLUSIVE) < 0)
 113         msg_fatal("lock %s: %m", mkmap->lock_file);
 114
 115     return (&mkmap->mkmap);
 116 }
 117
 118 #endif