kvm-connect.c

#define _GNU_SOURCE
#include <stdio.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/types.h>
/***********************************************************/
// The original, uncompressed Raritan jar file as char Array
// unsigned char raritan_uncompressed_jar[]
#include "raritan_uncompressed.h"
/***********************************************************/
#define CR "\n"
#define IP_START 0xC7120
#define PORT_ID_START 0xC71A1
#define HEADLINE_START 0x10342E
#define NUMBER_OF_KVMS 19
#define IP_LENGTH 13
#define PORT_ID_LENGTH 16
#define HEADLINE_LENGTH 24

int verbose = 0;
int kvmnumber = 0;

void printhelp()
{
    fprintf(stderr, "usage: ./Patcher -k kvmnumber [-v] [-h]" CR
                    "    -h        displays this help and exit"  CR
                    "    -k        takes the kvm-number as argument"  CR
                    "    -v        explain what is being done"  CR
                    CR
                    "For more details visit: http://twiki.molgen.mpg.de/foswiki/Medv/RaritanDominion" CR
                    CR
                    "(C) Niclas Hofmann"  CR
                    "Bugs to niclas@molgen.mpg.de"  CR
    );
}

//    The spaces are REQUIRED!!!
const char newIP[NUMBER_OF_KVMS][IP_LENGTH+1] = {
    "141.14.31.85 ", "141.14.31.86 ", "141.14.31.87 ", "141.14.31.88 ",
    "141.14.31.89 ", "141.14.31.90 ", "141.14.18.128", "141.14.18.129", 
    "141.14.18.130", "141.14.17.155", "141.14.17.157", "141.14.17.158", 
    "141.14.17.159", "141.14.17.160", "141.14.17.162", "141.14.17.163", 
    "141.14.17.152", "141.14.17.153", "141.14.17.154"
};
const char newPortID[NUMBER_OF_KVMS][PORT_ID_LENGTH+1] = { 
    "", "P_000d5d068313_0", "P_000d5d069245_0", "P_000d5d06830f_0", 
    "P_000d5d06830e_0", "P_000d5d069247_0", "P_000d5d0693a6_0", "P_000d5d067089_0", 
    "P_000d5d0693aa_0", "P_000d5d0af2f1_0", "P_000d5d0af2ea_0", "P_000d5d0af2ed_0", 
    "P_000d5d0af2eb_0", "P_000d5d0af2ef_0", "P_000d5d0af2ee_0", "P_000d5d0af2e9_0", 
    "P_000d5d0af2ec_0", "P_000d5d0af2e7_0", "P_000d5d0af2f0_0"
};

void get_options(int argc, char** argv)
{
    int option = 0;
    int kflag = 0; // To make sure just one kvm is chosen
    
    while((option = getopt(argc, argv, "vhk:")) != -1){
        switch(option){
            case 'h':
                printhelp();
                exit(EXIT_SUCCESS);
            case 'k':
                if (kflag == 1){
                    fprintf(stderr, "ERROR: -k is set multiple times\n");
                    printhelp();
                    exit(EXIT_FAILURE);
                }
                kflag = 1;
                kvmnumber = atoi(optarg)-1;
                if (kvmnumber < 0 || kvmnumber >= NUMBER_OF_KVMS){
                    fprintf(stderr, "ERROR: no possible kvm\n");
                    printhelp();
                    exit(EXIT_FAILURE);
                }
                break;
            case 'v':
                verbose = 1;
                break;
            default:
                printf("ERROR: no possible option\n");
                printhelp();
                exit(EXIT_FAILURE);
        }
    }
    
//    Checking if a KVM chosen?
    if (kflag == 0){
        fprintf(stderr, "ERROR: no kvm chosen\n");
        printhelp();
        exit(EXIT_FAILURE);
    }
    
    return;
}

void change_headline(int kvmnumber)
{
    char *newheadline = NULL;
    unsigned char *destinationInJar = NULL;
    
//    Chance the Headline
    if ((newheadline = calloc(HEADLINE_LENGTH+1, sizeof(char))) == NULL){
        fprintf(stderr, "ERROR: Could not allocate enough memory for"
                        "the new headline\n");
        exit(EXIT_FAILURE);
    }
    snprintf(newheadline, HEADLINE_LENGTH+1, "%s%2d%-19s", "KVM ", kvmnumber+1, " in use");
    destinationInJar = &raritan_uncompressed_jar[HEADLINE_START];
    memcpy(destinationInJar, newheadline, HEADLINE_LENGTH);
    
    if (verbose){
        printf("Headline changed.\n");
    }
    
    free(newheadline);
    
    return;
}

void change_ip(int kvmnumber)
{
    int i = 0;
    
//    Print old IP
    if (verbose){
        for(i = 0; i < IP_LENGTH; i++)
            printf("%c", raritan_uncompressed_jar[IP_START+i]);
        printf(" --> ");
    }
    
//    Change IP
    for(i = 0; i < IP_LENGTH; i++)
        raritan_uncompressed_jar[IP_START + i] = newIP[kvmnumber][i];
    
//    Print new IP
    if (verbose){
        for(i = 0; i < IP_LENGTH; i++)
            printf("%c", raritan_uncompressed_jar[IP_START+i]);
        printf(".\n");
    }
    
    return;
}

void change_portid(int kvmnumber)
{
    int i = 0;
    
    //    Print old PORT_ID
    if (verbose){
        for(i = 0; i < PORT_ID_LENGTH; i++)
            printf("%c", raritan_uncompressed_jar[PORT_ID_START+i]);
        printf(" --> ");
    }
    
//    Change PORT_ID
    for(i = 0; i < PORT_ID_LENGTH; i++)
        raritan_uncompressed_jar[PORT_ID_START + i] = newPortID[kvmnumber][i];
    
//    Print new PORT_ID
    if (verbose){
        for(i = 0; i < PORT_ID_LENGTH; i++)
            printf("%c", raritan_uncompressed_jar[PORT_ID_START+i]);
        printf(".\n");
    }
    
    return;
}

FILE* create_tmpfile(void)
{
    FILE* temp = NULL;
    
    if ((temp = tmpfile()) == NULL){
        perror("tmpfile()");
        exit(EXIT_FAILURE);
    }
    else{
        if (verbose){
            printf("Tempfile has been created.\n");
        }
    }
    
    return temp;
}

void write_to_file(FILE* file)
{
    int fd = fileno(file);
    
    if (write(fd, raritan_uncompressed_jar, sizeof(raritan_uncompressed_jar)) == -1){
        perror("write()");
        exit(EXIT_FAILURE);
    }
    else{
        if (verbose){
            printf("raritan_uncompressed_jar is written to the tempfile.\n");
        }
    }
    
    return;
}

void execute_raritan(FILE* file)
{
    char *exec = NULL;
    int fd = fileno(file);
    
//    Build the command
    if (asprintf(&exec, "java -jar /proc/self/fd/%d", fd) == -1){
        perror("asprintf()");
        exit(EXIT_FAILURE);
    }
    
//    Execute the temporary file
    if (system(exec) == -1){
        fprintf(stderr, "ERROR: Could not creat child process to execute: %s\n", exec);
        exit(EXIT_FAILURE);
    }
    
    free(exec);
    
    return;
}

int main(int argc, char **argv)
{
    FILE *temp_fp = NULL;
    
    get_options(argc, argv); // sets kvmnumber

    change_headline(kvmnumber);
   
    change_ip(kvmnumber);
    
    change_portid(kvmnumber);
    
    temp_fp = create_tmpfile();
    
    write_to_file(temp_fp);

    execute_raritan(temp_fp);

    fclose(temp_fp);
    
    return EXIT_SUCCESS;
}