// Copyright 2003 Data Helper, Inc.     
// This program is realeased under the 
// GNU GENERAL PUBLIC LICENSE Version 2.
// See COPYING.GPL for information.    
// Mark Willcox <pops@datahelper.com> 

// Run this after the POP connection is authenticated. 

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <limits.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

// The following are defined at compile time:
//   PASSWD     The file containing the required password, if any.
//   IP_DIR     The directory were the IP address files go.
//   DIR_DEPTH  Number of nodes to use as subdirectores.

int main( int argc, char **argv )
{
    int     fp;
    int     dot;
    char    ip[16];
    char    *lastDot;
    int     havePwd;
    char    fn[PATH_MAX];
    char    passwd[65];
    FILE    *pwf;

    // Are we expecting a password?
    havePwd = ( strlen( PASSWD ) > 0 );

    // Do we have enough arguments?  Optional password, next program.
    if (argc < (havePwd ? 3 : 2)) 
        _exit( 2 );

    // If we expect a password, check it.  If we don't get it, assume
    // someone is messing with us.
    if( havePwd )
    {
        pwf = fopen( PASSWD, "r" );
        if( ! pwf )
            _exit( 2 );
        fgets( passwd, 64, pwf );
        fclose( pwf );
 
        if( strncmp( argv[1], passwd, strlen( passwd ) - 1 ) != 0 )
        {
           puts( passwd);
           puts( "Security Violation: The postal police have been notified." );
           _exit( 2 );
        }
    }

    // Is the IP address there?  (If not, you need to run tcp-env first!) 
    if (! getenv( "TCPREMOTEIP"))
        _exit( 2 );

    // Sanity check on the IP address.   
    if (strlen( getenv( "TCPREMOTEIP")) > 15)
        _exit( 2 );

    // Grab the IP and make sure it's at LEAST the length of "0.0.0.0".
    strncpy( ip, getenv( "TCPREMOTEIP" ), 16 );
    if (strlen( ip ) < 7)
        _exit( 2 );

    // Base path. The place where the IP addres files go.
    strcpy( fn, IP_DIR );
    
    // If we're breaking the addresses out into subdirectories, take
    // the requested number of nodes and add them.
    for (dot = 0; dot < DIR_DEPTH; ++dot)
    {
        lastDot = strrchr( ip, '.' );
        if (! lastDot)
            _exit( 2 );

        *lastDot++ = '\0';
        strcat( fn, lastDot );

        // Make sure there's a directory at each level.
        mkdir( fn, 0755 );
        strcat( fn, "/" );
    }
    // Add the IP address at the end.
    strcat( fn, ip );
 
    // Touch the file.
    fp = creat( fn, S_IRWXU | S_IRGRP | S_IROTH ); 
    close( fp );

    // Run the next thing.
    if( havePwd )
        execvp(argv[2],argv + 2);
    else
        execvp(argv[1],argv + 1);
    _exit(111);
   
    return 0;
}