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      1 /*	$NetBSD: bounce_cleanup.c,v 1.1.1.1 2009/06/23 10:08:42 tron Exp $	*/
      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 }
    180