include/wvfork.h

   1 /* -*- Mode: C++ -*-
   2  * Worldvisions Weaver Software:
   3  *   Copyright (C) 1997-2002 Net Integration Technologies, Inc.
   4  */
   5 /** \file
   6  * Provides support for forking processes.
   7  */
   8
   9 #ifndef __WVFORK_H
  10 #define __WVFORK_H
  11
  12 #ifndef _WIN32
  13 #include <unistd.h>
  14 #else
  15 typedef int pid_t;
  16 #endif
  17
  18 #include "wvscatterhash.h"
  19 #include "wvtr1.h"
  20
  21 DeclareWvScatterTable(int);
  22 typedef wv::function<void(pid_t)> WvForkCallback;
  23
  24 /**
  25  * Register a callback to be called during wvfork.
  26  * It will be called (in both parent and child process) after the fork has
  27  * happened but before wvfork returns.  It is passed the return value of the
  28  * fork.
  29  *
  30  * NOTE: There is no way to undo this operation!
  31  */
  32 extern void add_wvfork_callback(WvForkCallback cb);
  33
  34 /**
  35  * wvfork_start is just like fork, except that it will block the
  36  * parent until the child process closes the waitfd, to avoid race
  37  * conditions.
  38  *
  39  * For example, wvfork uses it, closing the waitfd only when it is
  40  * done closing the close-on-exec file descriptors.
  41  */
  42 extern pid_t wvfork_start(int *waitfd);
  43
  44 /**
  45  * wvfork() just runs fork(), but it closes all file descriptors that
  46  * are flagged close-on-exec, since we don't necessarily always run
  47  * exec() after we fork()...
  48  *
  49  * This fixes the year-old mystery bug where WvTapeBackup caused
  50  * watchdog reboots because the CHILD process wasn't touching it, and
  51  * it was already open before the fork()...
  52  */
  53 extern pid_t wvfork(int dontclose1 = -1, int dontclose2 = -1);
  54 extern pid_t wvfork(intTable &dontclose );
  55
  56 #endif