/*
   mkstemps -- safely create a temporary filename from a template
   Copyright (C) 2004 Jaap Eldering (eldering@a-eskwadraat.nl).

   Uses the mkstemps function call from the GNU libiberty library.

   $Id: mkstemps.c 424 2004-08-26 21:06:34Z eldering $

   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, or (at your option)
   any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software Foundation,
   Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
   
 */

/* http://svn.a-eskwadraat.nl/wsvn/DOMjudge/branches/ipv6/bin/mkstemps.c?op=file&rev=0&sc=0 */

/* gcc -o mkstemps-test mkstemps-test.c -liberty */

#include <errno.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <stdarg.h>
#include <stdio.h>
#include <getopt.h>

/* Include some functions, which are not always available */
//#include "../lib/mkstemps.h"
//#include "../lib/basename.h"

#include <libiberty.h>

#define PROGRAM "mkstemps"
#define VERSION "0.1"
#define AUTHORS "Jaap Eldering"

extern int errno;

const int exit_failure = -1;

const char Xstring[] = "XXXXXX";

char *progname;

int show_help;
int show_version;

struct option const long_opts[] = {
        {"help",    no_argument,       &show_help,    1 },
        {"version", no_argument,       &show_version, 1 },
        { NULL,     0,                 NULL,          0 }
};

void error(int errnum, const char *format, ...)
{
        va_list ap;
        va_start(ap,format);
        
        fprintf(stderr,"%s",progname);
        
        if ( format!=NULL ) {
                fprintf(stderr,": ");
                vfprintf(stderr,format,ap);
        }
        if ( errnum!=0 ) {
                fprintf(stderr,": %s",strerror(errnum));
        }
        if ( format==NULL && errnum==0 ) {
                fprintf(stderr,": unknown error");
        }
        
        fprintf(stderr,"\nTry `%s --help' for more information.\n",progname);
        va_end(ap);
        
        exit(exit_failure);
}

void version()
{
        printf("%s -- version %s\n",PROGRAM,VERSION);
        printf("Written by %s\n\n",AUTHORS);
        printf("%s comes with ABSOLUTELY NO WARRANTY.  This is free software, and you\n",PROGRAM);
        printf("are welcome to redistribute it under certain conditions.  See the GNU\n");
        printf("General Public Licence for details.\n");
        exit(0);
}

void usage()
{
        printf("Usage: %s [OPTION]... TEMPLATE\n",progname);
        printf("Create a temporary file from TEMPLATE.\n\n");
        printf("      --help          display this help and exit\n");
        printf("      --version       output version information and exit\n");
        printf("\n");
        printf("TEMPLATE should be a filename containing at least 6 consecutive `X'\n");
        printf("characters in the base name. The last 6 of these are replaced by random\n");
        printf("letters and digits such that a unique file is created and returned.\n");
        exit(0);
}

int main(int argc, char **argv)
{
        char *template;
        char *filebase;
        char *ptr;
        char *next;
        char c;
        
        progname = argv[0];

        /* Parse command-line options */
        show_help = show_version = 0;
        opterr = 0;
        while ( (c = getopt_long(argc,argv,"",long_opts,(int *) 0))!=-1 ) {
                switch ( c ) {
                case 0:   /* long-only option */
                        break;
                case ':': /* getopt error */
                case '?':
                        error(0,"unknown option or missing argument `%c'",optopt);
                        break;
                default:
                        error(0,"getopt returned character code `%c' ??",c);
                }
        }

        if ( show_help ) usage();
        if ( show_version ) version();
        
        if ( argc<=optind ) error(0,"no template specified");

        template = argv[optind];

        /* Find the 6 X's in the template */
        filebase = basename(template);
        
        if ( strstr(filebase,Xstring)==NULL ) {
                error(0,"string %s not found in template",Xstring);
        }

        ptr = strstr(filebase,Xstring);
        while ( (next = strstr(&ptr[1],Xstring))!=NULL ) ptr = next;

        /* Call mkstemps to create the file from template */
        if ( mkstemps(template,strlen(ptr)-strlen(Xstring))<0 ) error(errno,NULL);

        printf("%s\n",template);
        
        return 0;
}