package charite.christo;
import java.io.File;
import java.io.IOException;
/**
   All Insecure operations such as file modification or running native
   code are chaneled through this class.
   This class contains all security checks.
   @author Christoph Gille
*/

public class Insecure {
    private final static boolean ALL_ALLOWED=true;
    public final static boolean
        CLASSLOADING_ALLOWED=ALL_ALLOWED,
        EXEC_ALLOWED=ALL_ALLOWED,
       	ARBITRARY_WORKING_DIRECTORY_ALLOWED=ALL_ALLOWED,
        UNCONTROLLED_FILE_MODIFICATION_ALLOWED=ALL_ALLOWED;
    public final static String
        TEXMF_DOT_CONF="/usr/share/texmf/web2c/texmf.cnf",
        DIR_DesktopUtils="/strap_utils/",
        DIR_STRAP_ALIGN="StrapAlign/",
        DIR_METANNOGEN="/metannogen/";
    /* --------------------------------------- */
    /* >>> Is file modification allowed ? >>> */
    private final static String
        ERROR="\u001B[45mError\u001B[0m in charite.christo.Insecure.java: ",
        ALLOWED_SUBSTRING[]={
        TEXMF_DOT_CONF,     TEXMF_DOT_CONF.replace('/','\\'),
        DIR_DesktopUtils, DIR_DesktopUtils.replace('/','\\'),
        DIR_STRAP_ALIGN,   DIR_STRAP_ALIGN.replace('/','\\'),
        DIR_METANNOGEN,     DIR_METANNOGEN.replace('/','\\'),
        "StrapAlign.ini",
        "/christo/java/"
    };
    private static String getPath(File f) {
        try {
            return f==null ? null : f.getCanonicalPath();
        } catch(IOException iox) { }
        return f.getAbsolutePath();
    }
    public static boolean canModify(File f) {
        if (f==null) return false;
        if (UNCONTROLLED_FILE_MODIFICATION_ALLOWED && !securityEnabled) return true;
        final String path=getPath(f);
        if (ARBITRARY_WORKING_DIRECTORY_ALLOWED && allowedPath!=null && path.startsWith(allowedPath)) return true;
        if (path.endsWith(".jnlp") && path.indexOf("strap")>=0) return true;
        for(String s : ALLOWED_SUBSTRING) if (path.indexOf(s)>=0) return true;
        /* Modification not allowed if beyond this point */
        System.out.println(ERROR+"canModify(File) failed for "+path);
        if (VIOLATIONS.get(path)==null) {
            final String stckTrc=stackTrceAsStrg(new IllegalAccessException(path));
            VIOLATIONS.put(path,stckTrc.intern());
            System.out.println(stckTrc);
        }
        return false;
    }
    private static String allowedPath;
    public static void securitySetAllowedPath(File dir) {
        if (ARBITRARY_WORKING_DIRECTORY_ALLOWED) {
            if (dir==null || (dir.exists() && !dir.isDirectory())) {
                System.out.println("dir="+dir);
                assert false;
            }
            allowedPath=getPath(dir);
        }
    }
    private static boolean securityEnabled;
    public static void setFileModificationControl(boolean b) {securityEnabled=b;}
    /* <<< Is file modification allowed ? <<< */
    /* ---------------------------------------- */
    /* >>> Report Violations >>> */
    public final static java.util.HashMap<String,String> VIOLATIONS=new java.util.HashMap();
    public static String stackTrceAsStrg(Throwable t) {
        java.io.ByteArrayOutputStream os=new  java.io.ByteArrayOutputStream();
        if (t==null) t=new Throwable();
        t.printStackTrace(new java.io.PrintStream(os));
        return os.toString();
    }
    public static void tellNoPermission(char what, String pfx) {
        final String
            w=what=='X'?"Execution of native code " : "",
            msg=
            " is disabled in STRAPlite.<br>\n"+
            "You can open STRAP with full functionality by pressing the Web-start button on the STRAP-home-page:<br>"+
            ChConstants.URL_STRAP+"<br><br>\n\n"+
            "You can exchange proteins between two STRAP views with the mouse using Drag-and-Drop.";
        ChUtils.error( w+pfx+msg);
    }
    /* >>> Report Violations >>> */
    /* ---------------------------------------- */
    /* >>> Native binaries  >>> */
    public static Process runtimeExec(String arg[], String[] env, File dir) throws IOException{
        return EXEC_ALLOWED ?  Runtime.getRuntime().exec(arg, env,dir) : null;
    }
    /* <<< Native binaries <<< */
    /* ---------------------------------------- */
    /* >>> File modification >>> */
    public static boolean renameToIgnoreSecurity(File fSrc, File fDest) {
        return fSrc!=null && fDest!=null && fSrc.renameTo(fDest);
    }
    static boolean renameFile(File src, File dest) {
        return canModify(src) && canModify(dest) ? src.renameTo(dest): false;
    }
    static boolean delFile(File f) {
        return canModify(f) ? f.delete() : false;
    }
    static java.io.OutputStream fileOutputStream(File f, boolean append) throws IOException {
        if (f==null) return null;
        if (canModify(f)) return new java.io.FileOutputStream(f,append);
        else {
            System.out.println(ERROR+"new FileOutputStream failed for "+f);
            throw new IOException("Insecure.java: "+f);
        }
    }
    static java.io.Writer fileWriter(File f) throws IOException {
        if (f==null) return null;
        if (canModify(f)) return new java.io.FileWriter(f);
        else {
            System.out.println(ERROR+"new FileWriter failed for "+f);
            throw new IOException("Insecure.java: "+f);
        }
    }
    public static java.io.RandomAccessFile randomAccessFile(File f, String mode) throws IOException {
        if (canModify(f)) return new java.io.RandomAccessFile(f, mode);
        else {
            System.out.println(ERROR+"new FileWriter failed for "+f);
            throw new IOException("Insecure.java: "+f);
        }
    }
    /* <<< File modification <<< */
    /* ---------------------------------------- */
    /* >>> Class loading >>> */
    public static Class findClassByName(final String cn) {
        if (cn==null) return null;
        if (CLASSLOADING_ALLOWED) return ChClassLoader.staticFindClass(cn);
        try {
            //System.out.println("findClassByName Class.forName "+cn);
            return Class.forName(cn);
        } catch(Throwable ex) {
            ChUtils.stckTrc(ex);
            tellNoPermission(' ', "Insecure.java: Class.forName("+cn+") failed\n\nMaybe that the requested operation ");
        }
        return null;
    }

}