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

   1 /*      $NetBSD$        */
   2
   3 /*++
   4 /* NAME
   5 /*      master_wakeup 3
   6 /* SUMMARY
   7 /*      Postfix master - start/stop service wakeup timers
   8 /* SYNOPSIS
   9 /*      #include "master.h"
  10 /*
  11 /*      void    master_wakeup_init(serv)
  12 /*      MASTER_SERV *serv;
  13 /*
  14 /*      void    master_wakeup_cleanup(serv)
  15 /*      MASTER_SERV *serv;
  16 /* DESCRIPTION
  17 /*      This module implements automatic service wakeup. In order to
  18 /*      wakeup a service, a wakeup trigger is sent to the corresponding
  19 /*      service port or FIFO, and a timer is started to repeat this sequence
  20 /*      after a configurable amount of time.
  21 /*
  22 /*      master_wakeup_init() wakes up the named service. No wakeup
  23 /*      is done or scheduled when a zero wakeup time is given, or when
  24 /*      the service has been throttled in the mean time.
  25 /*      It is OK to call master_wakeup_init() while a timer is already
  26 /*      running for the named service. The effect is to restart the
  27 /*      wakeup timer.
  28 /*
  29 /*      master_wakeup_cleanup() cancels the wakeup timer for the named
  30 /*      service. It is an error to disable a service while it still has
  31 /*      an active wakeup timer (doing so would cause a dangling reference
  32 /*      to a non-existent service).
  33 /*      It is OK to call master_wakeup_cleanup() even when no timer is
  34 /*      active for the named service.
  35 /* DIAGNOSTICS
  36 /* BUGS
  37 /* SEE ALSO
  38 /*      inet_trigger(3), internet-domain client
  39 /*      unix_trigger(3), unix-domain client
  40 /*      fifo_trigger(3), fifo client
  41 /*      upass_trigger(3), file descriptor passing client
  42 /* LICENSE
  43 /* .ad
  44 /* .fi
  45 /*      The Secure Mailer license must be distributed with this software.
  46 /* AUTHOR(S)
  47 /*      Wietse Venema
  48 /*      IBM T.J. Watson Research
  49 /*      P.O. Box 704
  50 /*      Yorktown Heights, NY 10598, USA
  51 /*--*/
  52
  53 /* System library. */
  54
  55 #include <sys_defs.h>
  56 #include <unistd.h>
  57 #include <string.h>
  58
  59 /* Utility library. */
  60
  61 #include <msg.h>
  62 #include <trigger.h>
  63 #include <events.h>
  64 #include <set_eugid.h>
  65 #include <set_ugid.h>
  66
  67 /* Global library. */
  68
  69 #include <mail_proto.h>                 /* triggers */
  70 #include <mail_params.h>
  71
  72 /* Application-specific. */
  73
  74 #include "mail_server.h"
  75 #include "master.h"
  76
  77 /* master_wakeup_timer_event - wakeup event handler */
  78
  79 static void master_wakeup_timer_event(int unused_event, char *context)
  80 {
  81     const char *myname = "master_wakeup_timer_event";
  82     MASTER_SERV *serv = (MASTER_SERV *) context;
  83     int     status;
  84     static char wakeup = TRIGGER_REQ_WAKEUP;
  85
  86     /*
  87      * Don't wakeup services whose automatic wakeup feature was turned off in
  88      * the mean time.
  89      */
  90     if (serv->wakeup_time == 0)
  91         return;
  92
  93     /*
  94      * Don't wake up services that are throttled. Find out what transport to
  95      * use. We can't block here so we choose a short timeout.
  96      */
  97 #define BRIEFLY 1
  98
  99     if (MASTER_THROTTLED(serv) == 0) {
 100         if (msg_verbose)
 101             msg_info("%s: service %s", myname, serv->name);
 102
 103         switch (serv->type) {
 104         case MASTER_SERV_TYPE_INET:
 105             status = inet_trigger(serv->name, &wakeup, sizeof(wakeup), BRIEFLY);
 106             break;
 107         case MASTER_SERV_TYPE_UNIX:
 108             status = LOCAL_TRIGGER(serv->name, &wakeup, sizeof(wakeup), BRIEFLY);
 109             break;
 110 #ifdef MASTER_SERV_TYPE_PASS
 111         case MASTER_SERV_TYPE_PASS:
 112             status = PASS_TRIGGER(serv->name, &wakeup, sizeof(wakeup), BRIEFLY);
 113             break;
 114 #endif
 115
 116             /*
 117              * If someone compromises the postfix account then this must not
 118              * overwrite files outside the chroot jail. Countermeasures:
 119              *
 120              * - Limit the damage by accessing the FIFO as postfix not root.
 121              *
 122              * - Have fifo_trigger() call safe_open() so we won't follow
 123              * arbitrary hard/symlinks to files in/outside the chroot jail.
 124              *
 125              * - All non-chroot postfix-related files must be root owned (or
 126              * postfix check complains).
 127              *
 128              * - The postfix user and group ID must not be shared with other
 129              * applications (says the INSTALL documentation).
 130              *
 131              * Result of a discussion with Michael Tokarev, who received his
 132              * insights from Solar Designer, who tested Postfix with a kernel
 133              * module that is paranoid about open() calls.
 134              */
 135         case MASTER_SERV_TYPE_FIFO:
 136             set_eugid(var_owner_uid, var_owner_gid);
 137             status = fifo_trigger(serv->name, &wakeup, sizeof(wakeup), BRIEFLY);
 138             set_ugid(getuid(), getgid());
 139             break;
 140         default:
 141             msg_panic("%s: unknown service type: %d", myname, serv->type);
 142         }
 143         if (status < 0)
 144             msg_warn("%s: service %s(%s): %m",
 145                      myname, serv->ext_name, serv->name);
 146     }
 147
 148     /*
 149      * Schedule another wakeup event.
 150      */
 151     event_request_timer(master_wakeup_timer_event, (char *) serv,
 152                         serv->wakeup_time);
 153 }
 154
 155 /* master_wakeup_init - start automatic service wakeup */
 156
 157 void    master_wakeup_init(MASTER_SERV *serv)
 158 {
 159     const char *myname = "master_wakeup_init";
 160
 161     if (serv->wakeup_time == 0 || (serv->flags & MASTER_FLAG_CONDWAKE))
 162         return;
 163     if (msg_verbose)
 164         msg_info("%s: service %s time %d",
 165                  myname, serv->name, serv->wakeup_time);
 166     master_wakeup_timer_event(0, (char *) serv);
 167 }
 168
 169 /* master_wakeup_cleanup - cancel wakeup timer */
 170
 171 void    master_wakeup_cleanup(MASTER_SERV *serv)
 172 {
 173     const char *myname = "master_wakeup_cleanup";
 174
 175     /*
 176      * Cleanup, even when the wakeup feature has been turned off. There might
 177      * still be a pending timer. Don't depend on the code that reloads the
 178      * config file to reset the wakeup timer when things change.
 179      */
 180     if (msg_verbose)
 181         msg_info("%s: service %s", myname, serv->name);
 182
 183     event_cancel_timer(master_wakeup_timer_event, (char *) serv);
 184 }