external/ibm-public/postfix/dist/src/master/master_watch.c

   1 /*      $NetBSD$        */
   2
   3 /*++
   4 /* NAME
   5 /*      master_watch 3
   6 /* SUMMARY
   7 /*      Postfix master - monitor main.cf changes
   8 /* SYNOPSIS
   9 /*      #include "master.h"
  10 /*
  11 /*      void    master_str_watch(str_watch_table)
  12 /*      const MASTER_STR_WATCH *str_watch_table;
  13 /*
  14 /*      void    master_int_watch(int_watch_table)
  15 /*      MASTER_INT_WATCH *int_watch_table;
  16 /* DESCRIPTION
  17 /*      The Postfix master daemon is a long-running process. After
  18 /*      main.cf is changed, some parameter changes may require that
  19 /*      master data structures be recomputed.
  20 /*
  21 /*      Unfortunately, some main.cf changes cannot be applied
  22 /*      on-the-fly, either because they require killing off existing
  23 /*      child processes and thus disrupt service, or because the
  24 /*      necessary support for on-the-fly data structure update has
  25 /*      not yet been implemented.  Such main.cf changes trigger a
  26 /*      warning that they require that Postfix be stopped and
  27 /*      restarted.
  28 /*
  29 /*      This module provides functions that monitor selected main.cf
  30 /*      parameters for change. The operation of these functions is
  31 /*      controlled by tables that specify the parameter name, the
  32 /*      current parameter value, a historical parameter value,
  33 /*      optional flags, and an optional notify call-back function.
  34 /*
  35 /*      master_str_watch() monitors string-valued parameters for
  36 /*      change, and master_int_watch() does the same for integer-valued
  37 /*      parameters. Note that master_int_watch() needs read-write
  38 /*      access to its argument table, while master_str_watch() needs
  39 /*      read-only access only.
  40 /*
  41 /*      The functions log a warning when a parameter value has
  42 /*      changed after re-reading main.cf, but the parameter is not
  43 /*      flagged in the MASTER_*_WATCH table as "updatable" with
  44 /*      MASTER_WATCH_FLAG_UPDATABLE.
  45 /*
  46 /*      If the parameter has a notify call-back function, then the
  47 /*      function is called after main.cf is read for the first time.
  48 /*      If the parameter is flagged as "updatable", then the function
  49 /*      is also called when the parameter value changes after
  50 /*      re-reading main.cf.
  51 /* LICENSE
  52 /* .ad
  53 /* .fi
  54 /*      The Secure Mailer license must be distributed with this software.
  55 /* AUTHOR(S)
  56 /*      Wietse Venema
  57 /*      IBM T.J. Watson Research
  58 /*      P.O. Box 704
  59 /*      Yorktown Heights, NY 10598, USA
  60 /*--*/
  61
  62 /* System library. */
  63
  64 #include <sys_defs.h>
  65 #include <string.h>
  66 #include <unistd.h>
  67
  68 /* Utility library. */
  69
  70 #include <msg.h>
  71 #include <mymalloc.h>
  72
  73 /* Application-specific. */
  74
  75 #include "master.h"
  76
  77 /* master_str_watch - watch string-valued parameters for change */
  78
  79 void    master_str_watch(const MASTER_STR_WATCH *str_watch_table)
  80 {
  81     const MASTER_STR_WATCH *wp;
  82
  83     for (wp = str_watch_table; wp->name != 0; wp++) {
  84
  85         /*
  86          * Detect changes to monitored parameter values. If a change is
  87          * supported, we discard the backed up value and update it to the
  88          * current value later. Otherwise we complain.
  89          */
  90         if (wp->backup[0] != 0
  91             && strcmp(wp->backup[0], wp->value[0]) != 0) {
  92             if ((wp->flags & MASTER_WATCH_FLAG_UPDATABLE) == 0) {
  93                 msg_warn("ignoring %s parameter value change", wp->name);
  94                 msg_warn("old value: \"%s\", new value: \"%s\"",
  95                          wp->backup[0], wp->value[0]);
  96                 msg_warn("to change %s, stop and start Postfix", wp->name);
  97             } else {
  98                 myfree(wp->backup[0]);
  99                 wp->backup[0] = 0;
 100             }
 101         }
 102
 103         /*
 104          * Initialize the backed up parameter value, or update it if this
 105          * parameter supports updates after initialization. Optionally
 106          * notify the application that this parameter has changed.
 107          */
 108         if (wp->backup[0] == 0) {
 109             if (wp->notify != 0)
 110                 wp->notify();
 111             wp->backup[0] = mystrdup(wp->value[0]);
 112         }
 113     }
 114 }
 115
 116 /* master_int_watch - watch integer-valued parameters for change */
 117
 118 void    master_int_watch(MASTER_INT_WATCH *int_watch_table)
 119 {
 120     MASTER_INT_WATCH *wp;
 121
 122     for (wp = int_watch_table; wp->name != 0; wp++) {
 123
 124         /*
 125          * Detect changes to monitored parameter values. If a change is
 126          * supported, we discard the backed up value and update it to the
 127          * current value later. Otherwise we complain.
 128          */
 129         if ((wp->flags & MASTER_WATCH_FLAG_ISSET) != 0
 130             && wp->backup != wp->value[0]) {
 131             if ((wp->flags & MASTER_WATCH_FLAG_UPDATABLE) == 0) {
 132                 msg_warn("ignoring %s parameter value change", wp->name);
 133                 msg_warn("old value: \"%d\", new value: \"%d\"",
 134                          wp->backup, wp->value[0]);
 135                 msg_warn("to change %s, stop and start Postfix", wp->name);
 136             } else {
 137                 wp->flags &= ~MASTER_WATCH_FLAG_ISSET;
 138             }
 139         }
 140
 141         /*
 142          * Initialize the backed up parameter value, or update if it this
 143          * parameter supports updates after initialization. Optionally
 144          * notify the application that this parameter has changed.
 145          */
 146         if ((wp->flags & MASTER_WATCH_FLAG_ISSET) == 0) {
 147             if (wp->notify != 0)
 148                 wp->notify();
 149             wp->flags |= MASTER_WATCH_FLAG_ISSET;
 150             wp->backup = wp->value[0];
 151         }
 152     }
 153 }