root/trunk/Update Checker Sources/main.m

//
//  main.m
//  Perian
//
//  Created by Augie Fackler on 1/7/07.
//  Copyright 2007 __MyCompanyName__. All rights reserved.
//

#import <Cocoa/Cocoa.h>
#include <sys/stat.h>
#include <unistd.h>

#define lockPath "/tmp/PerianUpdateLock"

static int fp = -1;

static void deleteLock()
{
        close(fp);
        unlink(lockPath);
}

int main(int argc, char *argv[])
{
        fp = open(lockPath, O_CREAT | O_EXCL);
        if(fp == -1)
        {
                struct stat lockfile;
                time_t current = time(NULL);
                if(stat(lockPath, &lockfile))
                {
                        if(lockfile.st_ctimespec.tv_sec + 60*60 > current)  //Only pay attention to lock file if it is no more than an hour old
                        {
                                unlink(lockPath);
                                fp = open(lockPath, O_CREAT | O_EXCL | O_EXLOCK);
                        }
                }               
        }
        if(fp == -1)
                return 0;
        
        atexit(deleteLock);

        int ret = NSApplicationMain(argc,  (const char **) argv);
        
        return ret;
}