// java.c
/*
 * The SelectVersion() routine ensures that an appropriate version of
 * the JRE is running.  The specification for the appropriate version
 * is obtained from either the manifest of a jar file (preferred) or
 * from command line options.
 * The routine also parses splash screen command line options and
 * passes on their values in private environment variables.
 */
static void
SelectVersion(int argc, char **argv, char **main_class)
{
    char    *arg;
    char    **new_argv;
    char    **new_argp;
    char    *operand;
    char    *version = NULL;
    char    *jre = NULL;
    int     jarflag = 0;
    int     headlessflag = 0;
    int     restrict_search = -1;               /* -1 implies not known */
    manifest_info info;
    char    env_entry[MAXNAMELEN + 24] = ENV_ENTRY "=";
    char    *splash_file_name = NULL;
    char    *splash_jar_name = NULL;
    char    *env_in;
    int     res;
    /*
     * If the version has already been selected, set *main_class
     * with the value passed through the environment (if any) and
     * simply return.
     */
    // _JAVA_VERSION_SET=
    if ((env_in = getenv(ENV_ENTRY)) != NULL) {
        if (*env_in != '\0')
            *main_class = JLI_StringDup(env_in);
        return;
    }
    /*
     * Scan through the arguments for options relevant to multiple JRE
     * support.  For reference, the command line syntax is defined as:
     *
     * SYNOPSIS
     *      java [options] class [argument...]
     *
     *      java [options] -jar file.jar [argument...]
     *
     * As the scan is performed, make a copy of the argument list with
     * the version specification options (new to 1.5) removed, so that
     * a version less than 1.5 can be exec'd.
     *
     * Note that due to the syntax of the native Windows interface
     * CreateProcess(), processing similar to the following exists in
     * the Windows platform specific routine ExecJRE (in java_md.c).
     * Changes here should be reproduced there.
     */
    new_argv = JLI_MemAlloc((argc + 1) * sizeof(char*));
    new_argv[0] = argv[0];
    new_argp = &new_argv[1];
    argc--;
    argv++;
    while ((arg = *argv) != 0 && *arg == '-') {
        if (JLI_StrCCmp(arg, "-version:") == 0) {
            version = arg + 9;
        } else if (JLI_StrCmp(arg, "-jre-restrict-search") == 0) {
            restrict_search = 1;
        } else if (JLI_StrCmp(arg, "-no-jre-restrict-search") == 0) {
            restrict_search = 0;
        } else {
            if (JLI_StrCmp(arg, "-jar") == 0)
                jarflag = 1;
            /* deal with "unfortunate" classpath syntax */
            if ((JLI_StrCmp(arg, "-classpath") == 0 || JLI_StrCmp(arg, "-cp") == 0) &&
              (argc >= 2)) {
                *new_argp++ = arg;
                argc--;
                argv++;
                arg = *argv;
            }
            /*
             * Checking for headless toolkit option in the some way as AWT does:
             * "true" means true and any other value means false
             */
            if (JLI_StrCmp(arg, "-Djava.awt.headless=true") == 0) {
                headlessflag = 1;
            } else if (JLI_StrCCmp(arg, "-Djava.awt.headless=") == 0) {
                headlessflag = 0;
            } else if (JLI_StrCCmp(arg, "-splash:") == 0) {
                splash_file_name = arg+8;
            }
            *new_argp++ = arg;
        }
        argc--;
        argv++;
    }
    if (argc <= 0) {    /* No operand? Possibly legit with -[full]version */
        operand = NULL;
    } else {
        argc--;
        *new_argp++ = operand = *argv++;
    }
    while (argc-- > 0)  /* Copy over [argument...] */
        *new_argp++ = *argv++;
    *new_argp = NULL;
    /*
     * If there is a jar file, read the manifest. If the jarfile can't be
     * read, the manifest can't be read from the jar file, or the manifest
     * is corrupt, issue the appropriate error messages and exit.
     *
     * Even if there isn't a jar file, construct a manifest_info structure
     * containing the command line information.  It's a convenient way to carry
     * this data around.
     */
    if (jarflag && operand) {
        if ((res = JLI_ParseManifest(operand, &info)) != 0) {
            if (res == -1)
                JLI_ReportErrorMessage(JAR_ERROR2, operand);
            else
                JLI_ReportErrorMessage(JAR_ERROR3, operand);
            exit(1);
        }
        /*
         * Command line splash screen option should have precedence
         * over the manifest, so the manifest data is used only if
         * splash_file_name has not been initialized above during command
         * line parsing
         */
        if (!headlessflag && !splash_file_name && info.splashscreen_image_file_name) {
            splash_file_name = info.splashscreen_image_file_name;
            splash_jar_name