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Diffstat (limited to 'src/master/master_watch.c')
| -rw-r--r-- | src/master/master_watch.c | 151 |
1 files changed, 151 insertions, 0 deletions
diff --git a/src/master/master_watch.c b/src/master/master_watch.c new file mode 100644 index 0000000..1af26fe --- /dev/null +++ b/src/master/master_watch.c @@ -0,0 +1,151 @@ +/*++ +/* 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]; + } + } +} |