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/*++
/* NAME
/* master_watch 3
/* SUMMARY
/* Postfix master - monitor main.cf changes
/* SYNOPSIS
/* #include "master.h"
/*
/* void master_str_watch(str_watch_table)
/* const MASTER_STR_WATCH *str_watch_table;
/*
/* void master_int_watch(int_watch_table)
/* MASTER_INT_WATCH *int_watch_table;
/* DESCRIPTION
/* The Postfix master daemon is a long-running process. After
/* main.cf is changed, some parameter changes may require that
/* master data structures be recomputed.
/*
/* Unfortunately, some main.cf changes cannot be applied
/* on-the-fly, either because they require killing off existing
/* child processes and thus disrupt service, or because the
/* necessary support for on-the-fly data structure update has
/* not yet been implemented. Such main.cf changes trigger a
/* warning that they require that Postfix be stopped and
/* restarted.
/*
/* This module provides functions that monitor selected main.cf
/* parameters for change. The operation of these functions is
/* controlled by tables that specify the parameter name, the
/* current parameter value, a historical parameter value,
/* optional flags, and an optional notify call-back function.
/*
/* master_str_watch() monitors string-valued parameters for
/* change, and master_int_watch() does the same for integer-valued
/* parameters. Note that master_int_watch() needs read-write
/* access to its argument table, while master_str_watch() needs
/* read-only access only.
/*
/* The functions log a warning when a parameter value has
/* changed after re-reading main.cf, but the parameter is not
/* flagged in the MASTER_*_WATCH table as "updatable" with
/* MASTER_WATCH_FLAG_UPDATABLE.
/*
/* If the parameter has a notify call-back function, then the
/* function is called after main.cf is read for the first time.
/* If the parameter is flagged as "updatable", then the function
/* is also called when the parameter value changes after
/* re-reading main.cf.
/* LICENSE
/* .ad
/* .fi
/* The Secure Mailer license must be distributed with this software.
/* AUTHOR(S)
/* Wietse Venema
/* IBM T.J. Watson Research
/* P.O. Box 704
/* Yorktown Heights, NY 10598, USA
/*--*/
/* System library. */
#include <sys_defs.h>
#include <string.h>
#include <unistd.h>
/* Utility library. */
#include <msg.h>
#include <mymalloc.h>
/* Application-specific. */
#include "master.h"
/* master_str_watch - watch string-valued parameters for change */
void master_str_watch(const MASTER_STR_WATCH *str_watch_table)
{
const MASTER_STR_WATCH *wp;
for (wp = str_watch_table; wp->name != 0; wp++) {
/*
* Detect changes to monitored parameter values. If a change is
* supported, we discard the backed up value and update it to the
* current value later. Otherwise we complain.
*/
if (wp->backup[0] != 0
&& strcmp(wp->backup[0], wp->value[0]) != 0) {
if ((wp->flags & MASTER_WATCH_FLAG_UPDATABLE) == 0) {
msg_warn("ignoring %s parameter value change", wp->name);
msg_warn("old value: \"%s\", new value: \"%s\"",
wp->backup[0], wp->value[0]);
msg_warn("to change %s, stop and start Postfix", wp->name);
} else {
myfree(wp->backup[0]);
wp->backup[0] = 0;
}
}
/*
* Initialize the backed up parameter value, or update it if this
* parameter supports updates after initialization. Optionally
* notify the application that this parameter has changed.
*/
if (wp->backup[0] == 0) {
if (wp->notify != 0)
wp->notify();
wp->backup[0] = mystrdup(wp->value[0]);
}
}
}
/* master_int_watch - watch integer-valued parameters for change */
void master_int_watch(MASTER_INT_WATCH *int_watch_table)
{
MASTER_INT_WATCH *wp;
for (wp = int_watch_table; wp->name != 0; wp++) {
/*
* Detect changes to monitored parameter values. If a change is
* supported, we discard the backed up value and update it to the
* current value later. Otherwise we complain.
*/
if ((wp->flags & MASTER_WATCH_FLAG_ISSET) != 0
&& wp->backup != wp->value[0]) {
if ((wp->flags & MASTER_WATCH_FLAG_UPDATABLE) == 0) {
msg_warn("ignoring %s parameter value change", wp->name);
msg_warn("old value: \"%d\", new value: \"%d\"",
wp->backup, wp->value[0]);
msg_warn("to change %s, stop and start Postfix", wp->name);
} else {
wp->flags &= ~MASTER_WATCH_FLAG_ISSET;
}
}
/*
* Initialize the backed up parameter value, or update if it this
* parameter supports updates after initialization. Optionally
* notify the application that this parameter has changed.
*/
if ((wp->flags & MASTER_WATCH_FLAG_ISSET) == 0) {
if (wp->notify != 0)
wp->notify();
wp->flags |= MASTER_WATCH_FLAG_ISSET;
wp->backup = wp->value[0];
}
}
}
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