external/ibm-public/postfix/dist/src/bounce/bounce_cleanup.c

   1 /*      $NetBSD$        */
   2
   3 /*++
   4 /* NAME
   5 /*      bounce_cleanup 3
   6 /* SUMMARY
   7 /*      cleanup logfile upon error
   8 /* SYNOPSIS
   9 /*      #include "bounce_service.h"
  10 /*
  11 /*      int     bounce_cleanup_registered()
  12 /*
  13 /*      void    bounce_cleanup_register(queue_id)
  14 /*      char    *queue_id;
  15 /*
  16 /*      void    bounce_cleanup_log(void)
  17 /*
  18 /*      void    bounce_cleanup_unregister(void)
  19 /* DESCRIPTION
  20 /*      This module implements support for deleting the current
  21 /*      bounce logfile in case of errors, and upon the arrival
  22 /*      of a SIGTERM signal (shutdown).
  23 /*
  24 /*      bounce_cleanup_register() registers a callback routine with the
  25 /*      run-time error handler, for automatic logfile removal in case
  26 /*      of a fatal run-time error.
  27 /*
  28 /*      bounce_cleanup_unregister() cleans up storage used by
  29 /*      bounce_cleanup_register().
  30 /*
  31 /*      In-between bounce_cleanup_register() and bounce_cleanup_unregister()
  32 /*      calls, a call of bounce_cleanup_log() will delete the registered
  33 /*      bounce logfile.
  34 /*
  35 /*      bounce_cleanup_registered() returns non-zero when a cleanup
  36 /*      trap has been set.
  37 /* DIAGNOSTICS
  38 /*      Fatal error: all file access errors. Panic: nested calls of
  39 /*      bounce_cleanup_register(); any calls of bounce_cleanup_unregister()
  40 /*      or bounce_cleanup_log() without preceding bounce_cleanup_register()
  41 /*      call.
  42 /* BUGS
  43 /* SEE ALSO
  44 /*      master(8) process manager
  45 /* LICENSE
  46 /* .ad
  47 /* .fi
  48 /*      The Secure Mailer license must be distributed with this software.
  49 /* AUTHOR(S)
  50 /*      Wietse Venema
  51 /*      IBM T.J. Watson Research
  52 /*      P.O. Box 704
  53 /*      Yorktown Heights, NY 10598, USA
  54 /*--*/
  55
  56 /* System library. */
  57
  58 #include <sys_defs.h>
  59 #include <unistd.h>
  60 #include <signal.h>
  61 #include <stdlib.h>
  62
  63 /* Utility library. */
  64
  65 #include <msg.h>
  66 #include <mymalloc.h>
  67 #include <vstring.h>
  68
  69 /* Global library. */
  70
  71 #include <mail_queue.h>
  72
  73 /* Application-specific. */
  74
  75 #include "bounce_service.h"
  76
  77  /*
  78   * Support for removing a logfile when an update fails. In order to do this,
  79   * we save a copy of the currently-open logfile name, and register a
  80   * callback function pointer with the run-time error handler. The saved
  81   * pathname is made global so that the application can see whether or not a
  82   * trap was set up.
  83   */
  84 static MSG_CLEANUP_FN bounce_cleanup_func;      /* saved callback */
  85 VSTRING *bounce_cleanup_path;           /* saved path name */
  86
  87 /* bounce_cleanup_callback - run-time callback to cleanup logfile */
  88
  89 static void bounce_cleanup_callback(void)
  90 {
  91
  92     /*
  93      * Remove the logfile.
  94      */
  95     if (bounce_cleanup_path)
  96         bounce_cleanup_log();
  97
  98     /*
  99      * Execute the saved cleanup action.
 100      */
 101     if (bounce_cleanup_func)
 102         bounce_cleanup_func();
 103 }
 104
 105 /* bounce_cleanup_log - clean up the logfile */
 106
 107 void    bounce_cleanup_log(void)
 108 {
 109     const char *myname = "bounce_cleanup_log";
 110
 111     /*
 112      * Sanity checks.
 113      */
 114     if (bounce_cleanup_path == 0)
 115         msg_panic("%s: no cleanup context", myname);
 116
 117     /*
 118      * This function may be called before a logfile is created or after it
 119      * has been deleted, so do not complain.
 120      */
 121     (void) unlink(vstring_str(bounce_cleanup_path));
 122 }
 123
 124 /* bounce_cleanup_sig - signal handler */
 125
 126 static void bounce_cleanup_sig(int sig)
 127 {
 128
 129     /*
 130      * Running as a signal handler - don't do complicated stuff.
 131      */
 132     if (bounce_cleanup_path)
 133         (void) unlink(vstring_str(bounce_cleanup_path));
 134     _exit(sig);
 135 }
 136
 137 /* bounce_cleanup_register - register logfile to clean up */
 138
 139 void    bounce_cleanup_register(char *service, char *queue_id)
 140 {
 141     const char *myname = "bounce_cleanup_register";
 142
 143     /*
 144      * Sanity checks.
 145      */
 146     if (bounce_cleanup_path)
 147         msg_panic("%s: nested call", myname);
 148
 149     /*
 150      * Save a copy of the logfile path, and of the last callback function
 151      * pointer registered with the run-time error handler.
 152      */
 153     bounce_cleanup_path = vstring_alloc(10);
 154     (void) mail_queue_path(bounce_cleanup_path, service, queue_id);
 155     bounce_cleanup_func = msg_cleanup(bounce_cleanup_callback);
 156     signal(SIGTERM, bounce_cleanup_sig);
 157 }
 158
 159 /* bounce_cleanup_unregister - unregister logfile to clean up */
 160
 161 void    bounce_cleanup_unregister(void)
 162 {
 163     const char *myname = "bounce_cleanup_unregister";
 164
 165     /*
 166      * Sanity checks.
 167      */
 168     if (bounce_cleanup_path == 0)
 169         msg_panic("%s: no cleanup context", myname);
 170
 171     /*
 172      * Restore the saved callback function pointer, and release storage for
 173      * the saved logfile pathname.
 174      */
 175     signal(SIGTERM, SIG_DFL);
 176     (void) msg_cleanup(bounce_cleanup_func);
 177     vstring_free(bounce_cleanup_path);
 178     bounce_cleanup_path = 0;
 179 }