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

   1 /*      $NetBSD$        */
   2
   3 /*++
   4 /* NAME
   5 /*      qmgr_scan 3
   6 /* SUMMARY
   7 /*      queue scanning
   8 /* SYNOPSIS
   9 /*      #include "qmgr.h"
  10 /*
  11 /*      QMGR_SCAN *qmgr_scan_create(queue_name)
  12 /*      const char *queue_name;
  13 /*
  14 /*      char    *qmgr_scan_next(scan_info)
  15 /*      QMGR_SCAN *scan_info;
  16 /*
  17 /*      void    qmgr_scan_request(scan_info, flags)
  18 /*      QMGR_SCAN *scan_info;
  19 /*      int     flags;
  20 /* DESCRIPTION
  21 /*      This module implements queue scans. A queue scan always runs
  22 /*      to completion, so that all files get a fair chance. The caller
  23 /*      can request that a queue scan be restarted once it completes.
  24 /*
  25 /*      qmgr_scan_create() creates a context for scanning the named queue,
  26 /*      but does not start a queue scan.
  27 /*
  28 /*      qmgr_scan_next() returns the base name of the next queue file.
  29 /*      A null pointer means that no file was found. qmgr_scan_next()
  30 /*      automagically restarts a queue scan when a scan request had
  31 /*      arrived while the scan was in progress.
  32 /*
  33 /*      qmgr_scan_request() records a request for the next queue scan. The
  34 /*      flags argument is the bit-wise OR of zero or more of the following,
  35 /*      unrecognized flags being ignored:
  36 /* .IP QMGR_FLUSH_ONCE
  37 /*      Forget state information about dead hosts or transports.
  38 /*      This request takes effect immediately.
  39 /* .IP QMGR_FLUSH_DFXP
  40 /*      Override the defer_transports setting. This takes effect
  41 /*      immediately when a queue scan is in progress, and affects
  42 /*      the next queue scan.
  43 /* .IP QMGR_SCAN_ALL
  44 /*      Ignore queue file time stamps. This takes effect immediately
  45 /*      when a queue scan is in progress, and affects the next queue
  46 /*      scan.
  47 /* .IP QMGR_SCAN_START
  48 /*      Start a queue scan when none is in progress, or restart the
  49 /*      current scan upon completion.
  50 /* DIAGNOSTICS
  51 /*      Fatal: out of memory.
  52 /*      Panic: interface violations, internal consistency errors.
  53 /* LICENSE
  54 /* .ad
  55 /* .fi
  56 /*      The Secure Mailer license must be distributed with this software.
  57 /* AUTHOR(S)
  58 /*      Wietse Venema
  59 /*      IBM T.J. Watson Research
  60 /*      P.O. Box 704
  61 /*      Yorktown Heights, NY 10598, USA
  62 /*--*/
  63
  64 /* System library. */
  65
  66 #include <sys_defs.h>
  67
  68 /* Utility library. */
  69
  70 #include <msg.h>
  71 #include <mymalloc.h>
  72 #include <scan_dir.h>
  73
  74 /* Global library. */
  75
  76 #include <mail_scan_dir.h>
  77
  78 /* Application-specific. */
  79
  80 #include "qmgr.h"
  81
  82 /* qmgr_scan_start - start queue scan */
  83
  84 static void qmgr_scan_start(QMGR_SCAN *scan_info)
  85 {
  86     const char *myname = "qmgr_scan_start";
  87
  88     /*
  89      * Sanity check.
  90      */
  91     if (scan_info->handle)
  92         msg_panic("%s: %s queue scan in progress",
  93                   myname, scan_info->queue);
  94
  95     /*
  96      * Give the poor tester a clue.
  97      */
  98     if (msg_verbose)
  99         msg_info("%s: %sstart %s queue scan",
 100                  myname,
 101                  scan_info->nflags & QMGR_SCAN_START ? "re" : "",
 102                  scan_info->queue);
 103
 104     /*
 105      * Start or restart the scan.
 106      */
 107     scan_info->flags = scan_info->nflags;
 108     scan_info->nflags = 0;
 109     scan_info->handle = scan_dir_open(scan_info->queue);
 110 }
 111
 112 /* qmgr_scan_request - request for future scan */
 113
 114 void    qmgr_scan_request(QMGR_SCAN *scan_info, int flags)
 115 {
 116
 117     /*
 118      * Apply "forget all dead destinations" requests immediately. Throttle
 119      * dead transports and queues at the earliest opportunity: preferably
 120      * during an already ongoing queue scan, otherwise the throttling will
 121      * have to wait until a "start scan" trigger arrives.
 122      *
 123      * The QMGR_FLUSH_ONCE request always comes with QMGR_FLUSH_DFXP, and
 124      * sometimes it also comes with QMGR_SCAN_ALL. It becomes a completely
 125      * different story when a flush request is encoded in file permissions.
 126      */
 127     if (flags & QMGR_FLUSH_ONCE)
 128         qmgr_enable_all();
 129
 130     /*
 131      * Apply "ignore time stamp" requests also towards the scan that is
 132      * already in progress.
 133      */
 134     if (scan_info->handle != 0 && (flags & QMGR_SCAN_ALL))
 135         scan_info->flags |= QMGR_SCAN_ALL;
 136
 137     /*
 138      * Apply "override defer_transports" requests also towards the scan that
 139      * is already in progress.
 140      */
 141     if (scan_info->handle != 0 && (flags & QMGR_FLUSH_DFXP))
 142         scan_info->flags |= QMGR_FLUSH_DFXP;
 143
 144     /*
 145      * If a scan is in progress, just record the request.
 146      */
 147     scan_info->nflags |= flags;
 148     if (scan_info->handle == 0 && (flags & QMGR_SCAN_START) != 0) {
 149         scan_info->nflags &= ~QMGR_SCAN_START;
 150         qmgr_scan_start(scan_info);
 151     }
 152 }
 153
 154 /* qmgr_scan_next - look for next queue file */
 155
 156 char   *qmgr_scan_next(QMGR_SCAN *scan_info)
 157 {
 158     char   *path = 0;
 159
 160     /*
 161      * Restart the scan if we reach the end and a queue scan request has
 162      * arrived in the mean time.
 163      */
 164     if (scan_info->handle && (path = mail_scan_dir_next(scan_info->handle)) == 0) {
 165         scan_info->handle = scan_dir_close(scan_info->handle);
 166         if (msg_verbose && (scan_info->nflags & QMGR_SCAN_START) == 0)
 167             msg_info("done %s queue scan", scan_info->queue);
 168     }
 169     if (!scan_info->handle && (scan_info->nflags & QMGR_SCAN_START)) {
 170         qmgr_scan_start(scan_info);
 171         path = mail_scan_dir_next(scan_info->handle);
 172     }
 173     return (path);
 174 }
 175
 176 /* qmgr_scan_create - create queue scan context */
 177
 178 QMGR_SCAN *qmgr_scan_create(const char *queue)
 179 {
 180     QMGR_SCAN *scan_info;
 181
 182     scan_info = (QMGR_SCAN *) mymalloc(sizeof(*scan_info));
 183     scan_info->queue = mystrdup(queue);
 184     scan_info->flags = scan_info->nflags = 0;
 185     scan_info->handle = 0;
 186     return (scan_info);
 187 }