external/ibm-public/postfix/dist/src/qmgr/qmgr_peer.c

   1 /*      $NetBSD$        */
   2
   3 /*++
   4 /* NAME
   5 /*      qmgr_peer 3
   6 /* SUMMARY
   7 /*      per-job peers
   8 /* SYNOPSIS
   9 /*      #include "qmgr.h"
  10 /*
  11 /*      QMGR_PEER *qmgr_peer_create(job, queue)
  12 /*      QMGR_JOB *job;
  13 /*      QMGR_QUEUE *queue;
  14 /*
  15 /*      QMGR_PEER *qmgr_peer_find(job, queue)
  16 /*      QMGR_JOB *job;
  17 /*      QMGR_QUEUE *queue;
  18 /*
  19 /*      QMGR_PEER *qmgr_peer_obtain(job, queue)
  20 /*      QMGR_JOB *job;
  21 /*      QMGR_QUEUE *queue;
  22 /*
  23 /*      void qmgr_peer_free(peer)
  24 /*      QMGR_PEER *peer;
  25 /*
  26 /*      QMGR_PEER *qmgr_peer_select(job)
  27 /*      QMGR_JOB *job;
  28 /*
  29 /* DESCRIPTION
  30 /*      These routines add/delete/manipulate per-job peers.
  31 /*      Each peer corresponds to a specific job and destination.
  32 /*      It is similar to per-transport queue structure, but groups
  33 /*      only the entries of the given job.
  34 /*
  35 /*      qmgr_peer_create() creates an empty peer structure for the named
  36 /*      job and destination. It is an error to call this function
  37 /*      if a peer for given combination already exists.
  38 /*
  39 /*      qmgr_peer_find() looks up the peer for the named destination
  40 /*      for the named job. A null result means that the peer
  41 /*      was not found.
  42 /*
  43 /*      qmgr_peer_obtain() looks up the peer for the named destination
  44 /*      for the named job. If it doesn't exist yet, it creates it.
  45 /*
  46 /*      qmgr_peer_free() disposes of a per-job peer after all
  47 /*      its entries have been taken care of. It is an error to dispose
  48 /*      of a peer still in use.
  49 /*
  50 /*      qmgr_peer_select() attempts to find a peer of named job that
  51 /*      has messages pending delivery.  This routine implements
  52 /*      round-robin search among job's peers.
  53 /* DIAGNOSTICS
  54 /*      Panic: consistency check failure.
  55 /* LICENSE
  56 /* .ad
  57 /* .fi
  58 /*      The Secure Mailer license must be distributed with this software.
  59 /* AUTHOR(S)
  60 /*      Patrik Rak
  61 /*      patrik@raxoft.cz
  62 /*--*/
  63
  64 /* System library. */
  65
  66 #include <sys_defs.h>
  67
  68 /* Utility library. */
  69
  70 #include <msg.h>
  71 #include <htable.h>
  72 #include <mymalloc.h>
  73
  74 /* Application-specific. */
  75
  76 #include "qmgr.h"
  77
  78 /* qmgr_peer_create - create and initialize message peer structure */
  79
  80 QMGR_PEER *qmgr_peer_create(QMGR_JOB *job, QMGR_QUEUE *queue)
  81 {
  82     QMGR_PEER *peer;
  83
  84     peer = (QMGR_PEER *) mymalloc(sizeof(QMGR_PEER));
  85     peer->queue = queue;
  86     peer->job = job;
  87     QMGR_LIST_APPEND(job->peer_list, peer, peers);
  88     htable_enter(job->peer_byname, queue->name, (char *) peer);
  89     peer->refcount = 0;
  90     QMGR_LIST_INIT(peer->entry_list);
  91     return (peer);
  92 }
  93
  94 /* qmgr_peer_free - release peer structure */
  95
  96 void    qmgr_peer_free(QMGR_PEER *peer)
  97 {
  98     const char *myname = "qmgr_peer_free";
  99     QMGR_JOB *job = peer->job;
 100     QMGR_QUEUE *queue = peer->queue;
 101
 102     /*
 103      * Sanity checks. It is an error to delete a referenced peer structure.
 104      */
 105     if (peer->refcount != 0)
 106         msg_panic("%s: refcount: %d", myname, peer->refcount);
 107     if (peer->entry_list.next != 0)
 108         msg_panic("%s: entry list not empty: %s", myname, queue->name);
 109
 110     QMGR_LIST_UNLINK(job->peer_list, QMGR_PEER *, peer, peers);
 111     htable_delete(job->peer_byname, queue->name, (void (*) (char *)) 0);
 112     myfree((char *) peer);
 113 }
 114
 115 /* qmgr_peer_find - lookup peer associated with given job and queue */
 116
 117 QMGR_PEER *qmgr_peer_find(QMGR_JOB *job, QMGR_QUEUE *queue)
 118 {
 119     return ((QMGR_PEER *) htable_find(job->peer_byname, queue->name));
 120 }
 121
 122 /* qmgr_peer_obtain - find/create peer associated with given job and queue */
 123
 124 QMGR_PEER *qmgr_peer_obtain(QMGR_JOB *job, QMGR_QUEUE *queue)
 125 {
 126     QMGR_PEER *peer;
 127
 128     if ((peer = qmgr_peer_find(job, queue)) == 0)
 129         peer = qmgr_peer_create(job, queue);
 130     return (peer);
 131 }
 132
 133 /* qmgr_peer_select - select next peer suitable for delivery within given job */
 134
 135 QMGR_PEER *qmgr_peer_select(QMGR_JOB *job)
 136 {
 137     QMGR_PEER *peer;
 138     QMGR_QUEUE *queue;
 139
 140     /*
 141      * If we find a suitable site, rotate the list to enforce round-robin
 142      * selection. See similar selection code in qmgr_transport_select().
 143      */
 144     for (peer = job->peer_list.next; peer; peer = peer->peers.next) {
 145         queue = peer->queue;
 146         if (queue->window > queue->busy_refcount && peer->entry_list.next != 0) {
 147             QMGR_LIST_ROTATE(job->peer_list, peer, peers);
 148             if (msg_verbose)
 149                 msg_info("qmgr_peer_select: %s %s %s (%d of %d)",
 150                 job->message->queue_id, queue->transport->name, queue->name,
 151                          queue->busy_refcount + 1, queue->window);
 152             return (peer);
 153         }
 154     }
 155     return (0);
 156 }