+++ /dev/null
-/*****************************************************************************\
-* *
-* Name : rendezvous *
-* Author : Chris Koeritz *
-* *
-*******************************************************************************
-* Copyright (c) 2001-$now By Author. This program is free software; you can *
-* redistribute it and/or modify it under the terms of the GNU General Public *
-* License as published by the Free Software Foundation; either version 2 of *
-* the License or (at your option) any later version. This is online at: *
-* http://www.fsf.org/copyleft/gpl.html *
-* Please send any updates to: fred@gruntose.com *
-\*****************************************************************************/
-
-//note: after repeated investigation, it seems that if we unlink the rendezvous
-// file on destruction, then this hoses up any locks attempted ever after.
-// instead of waiting for a lock, new attempts think they can go ahead,
-// even though someone else might also have been given the lock. it seems
-// we cannot remove the files without destroying the semantics.
-
-#include "rendezvous.h"
-
-#include <application/windoze_helper.h>
-#include <basis/astring.h>
-#include <basis/functions.h>
-#include <basis/utf_conversion.h>
-#include <filesystem/filename.h>
-
-#ifdef __UNIX__
- #include <stdio.h>
- #include <sys/stat.h>
- #include <unistd.h>
-#endif
-
-using namespace basis;
-using namespace filesystem;
-
-namespace processes {
-
-//#define DEBUG_RENDEZVOUS
- // uncomment for a noisier file.
-
-#undef LOG
-#define LOG(tp) printf("%s%s\n", time_stamp::notarize(true).s(), astring(tp).s())
- // we can only use simple logging here since the rendezvous is relied on
- // at very low levels and use of a log_base object would cause infinite
- // loops.
-
-// used for the name of a mutex or part of the unix lock filename.
-astring general_lock_name(const astring &root_part)
-{ return root_part + "_app_lock"; }
-
-#ifdef __UNIX__
-// the name of the locking file used in unix.
-astring unix_rendez_file(const astring &lock_name)
-{
- astring clean_name = lock_name;
- // remove troublesome characters from the name.
- filename::detooth_filename(clean_name);
- // make sure our target directory exists.
-
- // this choice is only user specific.
-// astring tmp_dir = portable::env_string("TMP") + "/rendezvous";
-
- // this choice uses a system-wide location.
- astring tmp_dir = "/tmp/rendezvous";
-
- mkdir(tmp_dir.observe(), 0777);
- return tmp_dir + "/ren_" + clean_name;
-}
-#endif
-
-rendezvous::rendezvous(const astring &root_name)
-: _handle(NIL),
- _locked(false),
- _root_name(new astring(root_name))
-{
-#ifdef DEBUG_RENDEZVOUS
- FUNCDEF("constructor");
-#endif
- astring lock_name = general_lock_name(root_name);
-#ifdef __UNIX__
- astring real_name = unix_rendez_file(lock_name);
- FILE *locking_file = fopen(real_name.s(), "wb");
- if (!locking_file) {
-#ifdef DEBUG_RENDEZVOUS
- LOG(astring("failure to create locking file ") + real_name
- + ": " + critical_events::system_error_text(critical_events::system_error()) );
-#endif
- return;
- }
- // success now.
- _handle = locking_file;
-#endif
-#ifdef __WIN32__
- _handle = CreateMutex(NIL, false, to_unicode_temp(lock_name));
- if (!_handle) return;
-#endif
-}
-
-rendezvous::~rendezvous()
-{
-#ifdef DEBUG_RENDEZVOUS
- FUNCDEF("destructor");
- LOG("okay, into destructor for rendezvous.");
-#endif
-#ifdef __UNIX__
- if (_handle) {
- if (_locked) {
- int ret = lockf(fileno((FILE *)_handle), F_ULOCK, sizeof(int));
- if (ret) {
-#ifdef DEBUG_RENDEZVOUS
- LOG("failure to get lock on file.");
-#endif
- }
- _locked = false; // clear our locked status since we no longer have one.
-
-//note: after repeated investigation, it seems that if we unlink the rendezvous
-// file on destruction, then this hoses up any locks attempted ever after.
-// instead of waiting for a lock, new attempts think they can go ahead,
-// even though someone else might also have been given the lock. it seems
-// we cannot remove the files without destroying the semantics.
- }
-
- fclose((FILE *)_handle);
- _handle = NIL;
- }
-#endif
-#ifdef __WIN32__
- if (_handle) CloseHandle((HANDLE)_handle);
-#endif
- WHACK(_root_name);
-}
-
-void rendezvous::establish_lock() { lock(); }
-
-void rendezvous::repeal_lock() { unlock(); }
-
-bool rendezvous::healthy() const
-{
- return !!_handle;
-}
-
-bool rendezvous::lock(locking_methods how)
-{
-#ifdef DEBUG_RENDEZVOUS
- FUNCDEF("lock");
-#endif
- if (how == NO_LOCKING) return false;
- if (!healthy()) return false;
-#ifdef __UNIX__
- int command = F_TLOCK;
- if (how == ENDLESS_WAIT) command = F_LOCK;
- int ret = lockf(fileno((FILE *)_handle), command, sizeof(int));
- if (ret) {
-#ifdef DEBUG_RENDEZVOUS
- LOG("failure to get lock on file.");
-#endif
- return false;
- }
-#ifdef DEBUG_RENDEZVOUS
- LOG("okay, got lock on shared mem.");
-#endif
- _locked = true;
- return true;
-#endif
-#ifdef __WIN32__
- int timing = 0; // immediate return.
- if (how == ENDLESS_WAIT) timing = INFINITE;
- int ret = WaitForSingleObject((HANDLE)_handle, timing);
- if ( (ret == WAIT_ABANDONED) || (ret == WAIT_TIMEOUT) ) return false;
- else if (ret != WAIT_OBJECT_0) {
-#ifdef DEBUG_RENDEZVOUS
- LOG("got an unanticipated error from waiting for the mutex.");
-#endif
- return false;
- }
- _locked = true;
- return true;
-#endif
- return false;
-}
-
-void rendezvous::unlock()
-{
-#ifdef DEBUG_RENDEZVOUS
- FUNCDEF("unlock");
-#endif
- if (!healthy()) return;
- if (_locked) {
-#ifdef __UNIX__
- int ret = lockf(fileno((FILE *)_handle), F_ULOCK, sizeof(int));
- if (ret) {
-#ifdef DEBUG_RENDEZVOUS
- LOG("failure to get lock on file.");
-#endif
- }
-#endif
-#ifdef __WIN32__
- ReleaseMutex((HANDLE)_handle);
-#endif
- _locked = false;
- } else {
-#ifdef DEBUG_RENDEZVOUS
- LOG("okay, rendezvous wasn't locked.");
-#endif
- }
-}
-
-} //namespace.
-
projects / feisty_meow.git / blobdiff